fs/btrfs/volumes.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/bio.h>
  20 #include <linux/slab.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/random.h>
  24 #include <linux/iocontext.h>
  25 #include <linux/capability.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/kthread.h>
  28 #include "compat.h"
  29 #include "ctree.h"
  30 #include "extent_map.h"
  31 #include "disk-io.h"
  32 #include "transaction.h"
  33 #include "print-tree.h"
  34 #include "volumes.h"
  35 #include "async-thread.h"
  36 #include "check-integrity.h"
  37 #include "rcu-string.h"
  38 #include "math.h"
  39
  40 static int init_first_rw_device(struct btrfs_trans_handle *trans,
  41                                 struct btrfs_root *root,
  42                                 struct btrfs_device *device);
  43 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
  44 static void __btrfs_reset_dev_stats(struct btrfs_device *dev);
  45 static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);
  46
  47 static DEFINE_MUTEX(uuid_mutex);
  48 static LIST_HEAD(fs_uuids);
  49
  50 static void lock_chunks(struct btrfs_root *root)
  51 {
  52         mutex_lock(&root->fs_info->chunk_mutex);
  53 }
  54
  55 static void unlock_chunks(struct btrfs_root *root)
  56 {
  57         mutex_unlock(&root->fs_info->chunk_mutex);
  58 }
  59
  60 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
  61 {
  62         struct btrfs_device *device;
  63         WARN_ON(fs_devices->opened);
  64         while (!list_empty(&fs_devices->devices)) {
  65                 device = list_entry(fs_devices->devices.next,
  66                                     struct btrfs_device, dev_list);
  67                 list_del(&device->dev_list);
  68                 rcu_string_free(device->name);
  69                 kfree(device);
  70         }
  71         kfree(fs_devices);
  72 }
  73
  74 void btrfs_cleanup_fs_uuids(void)
  75 {
  76         struct btrfs_fs_devices *fs_devices;
  77
  78         while (!list_empty(&fs_uuids)) {
  79                 fs_devices = list_entry(fs_uuids.next,
  80                                         struct btrfs_fs_devices, list);
  81                 list_del(&fs_devices->list);
  82                 free_fs_devices(fs_devices);
  83         }
  84 }
  85
  86 static noinline struct btrfs_device *__find_device(struct list_head *head,
  87                                                    u64 devid, u8 *uuid)
  88 {
  89         struct btrfs_device *dev;
  90
  91         list_for_each_entry(dev, head, dev_list) {
  92                 if (dev->devid == devid &&
  93                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
  94                         return dev;
  95                 }
  96         }
  97         return NULL;
  98 }
  99
 100 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
 101 {
 102         struct btrfs_fs_devices *fs_devices;
 103
 104         list_for_each_entry(fs_devices, &fs_uuids, list) {
 105                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
 106                         return fs_devices;
 107         }
 108         return NULL;
 109 }
 110
 111 static void requeue_list(struct btrfs_pending_bios *pending_bios,
 112                         struct bio *head, struct bio *tail)
 113 {
 114
 115         struct bio *old_head;
 116
 117         old_head = pending_bios->head;
 118         pending_bios->head = head;
 119         if (pending_bios->tail)
 120                 tail->bi_next = old_head;
 121         else
 122                 pending_bios->tail = tail;
 123 }
 124
 125 /*
 126  * we try to collect pending bios for a device so we don't get a large
 127  * number of procs sending bios down to the same device.  This greatly
 128  * improves the schedulers ability to collect and merge the bios.
 129  *
 130  * But, it also turns into a long list of bios to process and that is sure
 131  * to eventually make the worker thread block.  The solution here is to
 132  * make some progress and then put this work struct back at the end of
 133  * the list if the block device is congested.  This way, multiple devices
 134  * can make progress from a single worker thread.
 135  */
 136 static noinline void run_scheduled_bios(struct btrfs_device *device)
 137 {
 138         struct bio *pending;
 139         struct backing_dev_info *bdi;
 140         struct btrfs_fs_info *fs_info;
 141         struct btrfs_pending_bios *pending_bios;
 142         struct bio *tail;
 143         struct bio *cur;
 144         int again = 0;
 145         unsigned long num_run;
 146         unsigned long batch_run = 0;
 147         unsigned long limit;
 148         unsigned long last_waited = 0;
 149         int force_reg = 0;
 150         int sync_pending = 0;
 151         struct blk_plug plug;
 152
 153         /*
 154          * this function runs all the bios we've collected for
 155          * a particular device.  We don't want to wander off to
 156          * another device without first sending all of these down.
 157          * So, setup a plug here and finish it off before we return
 158          */
 159         blk_start_plug(&plug);
 160
 161         bdi = blk_get_backing_dev_info(device->bdev);
 162         fs_info = device->dev_root->fs_info;
 163         limit = btrfs_async_submit_limit(fs_info);
 164         limit = limit * 2 / 3;
 165
 166 loop:
 167         spin_lock(&device->io_lock);
 168
 169 loop_lock:
 170         num_run = 0;
 171
 172         /* take all the bios off the list at once and process them
 173          * later on (without the lock held).  But, remember the
 174          * tail and other pointers so the bios can be properly reinserted
 175          * into the list if we hit congestion
 176          */
 177         if (!force_reg && device->pending_sync_bios.head) {
 178                 pending_bios = &device->pending_sync_bios;
 179                 force_reg = 1;
 180         } else {
 181                 pending_bios = &device->pending_bios;
 182                 force_reg = 0;
 183         }
 184
 185         pending = pending_bios->head;
 186         tail = pending_bios->tail;
 187         WARN_ON(pending && !tail);
 188
 189         /*
 190          * if pending was null this time around, no bios need processing
 191          * at all and we can stop.  Otherwise it'll loop back up again
 192          * and do an additional check so no bios are missed.
 193          *
 194          * device->running_pending is used to synchronize with the
 195          * schedule_bio code.
 196          */
 197         if (device->pending_sync_bios.head == NULL &&
 198             device->pending_bios.head == NULL) {
 199                 again = 0;
 200                 device->running_pending = 0;
 201         } else {
 202                 again = 1;
 203                 device->running_pending = 1;
 204         }
 205
 206         pending_bios->head = NULL;
 207         pending_bios->tail = NULL;
 208
 209         spin_unlock(&device->io_lock);
 210
 211         while (pending) {
 212
 213                 rmb();
 214                 /* we want to work on both lists, but do more bios on the
 215                  * sync list than the regular list
 216                  */
 217                 if ((num_run > 32 &&
 218                     pending_bios != &device->pending_sync_bios &&
 219                     device->pending_sync_bios.head) ||
 220                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
 221                     device->pending_bios.head)) {
 222                         spin_lock(&device->io_lock);
 223                         requeue_list(pending_bios, pending, tail);
 224                         goto loop_lock;
 225                 }
 226
 227                 cur = pending;
 228                 pending = pending->bi_next;
 229                 cur->bi_next = NULL;
 230
 231                 if (atomic_dec_return(&fs_info->nr_async_bios) < limit &&
 232                     waitqueue_active(&fs_info->async_submit_wait))
 233                         wake_up(&fs_info->async_submit_wait);
 234
 235                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
 236
 237                 /*
 238                  * if we're doing the sync list, record that our
 239                  * plug has some sync requests on it
 240                  *
 241                  * If we're doing the regular list and there are
 242                  * sync requests sitting around, unplug before
 243                  * we add more
 244                  */
 245                 if (pending_bios == &device->pending_sync_bios) {
 246                         sync_pending = 1;
 247                 } else if (sync_pending) {
 248                         blk_finish_plug(&plug);
 249                         blk_start_plug(&plug);
 250                         sync_pending = 0;
 251                 }
 252
 253                 btrfsic_submit_bio(cur->bi_rw, cur);
 254                 num_run++;
 255                 batch_run++;
 256                 if (need_resched())
 257                         cond_resched();
 258
 259                 /*
 260                  * we made progress, there is more work to do and the bdi
 261                  * is now congested.  Back off and let other work structs
 262                  * run instead
 263                  */
 264                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
 265                     fs_info->fs_devices->open_devices > 1) {
 266                         struct io_context *ioc;
 267
 268                         ioc = current->io_context;
 269
 270                         /*
 271                          * the main goal here is that we don't want to
 272                          * block if we're going to be able to submit
 273                          * more requests without blocking.
 274                          *
 275                          * This code does two great things, it pokes into
 276                          * the elevator code from a filesystem _and_
 277                          * it makes assumptions about how batching works.
 278                          */
 279                         if (ioc && ioc->nr_batch_requests > 0 &&
 280                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
 281                             (last_waited == 0 ||
 282                              ioc->last_waited == last_waited)) {
 283                                 /*
 284                                  * we want to go through our batch of
 285                                  * requests and stop.  So, we copy out
 286                                  * the ioc->last_waited time and test
 287                                  * against it before looping
 288                                  */
 289                                 last_waited = ioc->last_waited;
 290                                 if (need_resched())
 291                                         cond_resched();
 292                                 continue;
 293                         }
 294                         spin_lock(&device->io_lock);
 295                         requeue_list(pending_bios, pending, tail);
 296                         device->running_pending = 1;
 297
 298                         spin_unlock(&device->io_lock);
 299                         btrfs_requeue_work(&device->work);
 300                         goto done;
 301                 }
 302                 /* unplug every 64 requests just for good measure */
 303                 if (batch_run % 64 == 0) {
 304                         blk_finish_plug(&plug);
 305                         blk_start_plug(&plug);
 306                         sync_pending = 0;
 307                 }
 308         }
 309
 310         cond_resched();
 311         if (again)
 312                 goto loop;
 313
 314         spin_lock(&device->io_lock);
 315         if (device->pending_bios.head || device->pending_sync_bios.head)
 316                 goto loop_lock;
 317         spin_unlock(&device->io_lock);
 318
 319 done:
 320         blk_finish_plug(&plug);
 321 }
 322
 323 static void pending_bios_fn(struct btrfs_work *work)
 324 {
 325         struct btrfs_device *device;
 326
 327         device = container_of(work, struct btrfs_device, work);
 328         run_scheduled_bios(device);
 329 }
 330
 331 static noinline int device_list_add(const char *path,
 332                            struct btrfs_super_block *disk_super,
 333                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 334 {
 335         struct btrfs_device *device;
 336         struct btrfs_fs_devices *fs_devices;
 337         struct rcu_string *name;
 338         u64 found_transid = btrfs_super_generation(disk_super);
 339
 340         fs_devices = find_fsid(disk_super->fsid);
 341         if (!fs_devices) {
 342                 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 343                 if (!fs_devices)
 344                         return -ENOMEM;
 345                 INIT_LIST_HEAD(&fs_devices->devices);
 346                 INIT_LIST_HEAD(&fs_devices->alloc_list);
 347                 list_add(&fs_devices->list, &fs_uuids);
 348                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
 349                 fs_devices->latest_devid = devid;
 350                 fs_devices->latest_trans = found_transid;
 351                 mutex_init(&fs_devices->device_list_mutex);
 352                 device = NULL;
 353         } else {
 354                 device = __find_device(&fs_devices->devices, devid,
 355                                        disk_super->dev_item.uuid);
 356         }
 357         if (!device) {
 358                 if (fs_devices->opened)
 359                         return -EBUSY;
 360
 361                 device = kzalloc(sizeof(*device), GFP_NOFS);
 362                 if (!device) {
 363                         /* we can safely leave the fs_devices entry around */
 364                         return -ENOMEM;
 365                 }
 366                 device->devid = devid;
 367                 device->dev_stats_valid = 0;
 368                 device->work.func = pending_bios_fn;
 369                 memcpy(device->uuid, disk_super->dev_item.uuid,
 370                        BTRFS_UUID_SIZE);
 371                 spin_lock_init(&device->io_lock);
 372
 373                 name = rcu_string_strdup(path, GFP_NOFS);
 374                 if (!name) {
 375                         kfree(device);
 376                         return -ENOMEM;
 377                 }
 378                 rcu_assign_pointer(device->name, name);
 379                 INIT_LIST_HEAD(&device->dev_alloc_list);
 380
 381                 /* init readahead state */
 382                 spin_lock_init(&device->reada_lock);
 383                 device->reada_curr_zone = NULL;
 384                 atomic_set(&device->reada_in_flight, 0);
 385                 device->reada_next = 0;
 386                 INIT_RADIX_TREE(&device->reada_zones, GFP_NOFS & ~__GFP_WAIT);
 387                 INIT_RADIX_TREE(&device->reada_extents, GFP_NOFS & ~__GFP_WAIT);
 388
 389                 mutex_lock(&fs_devices->device_list_mutex);
 390                 list_add_rcu(&device->dev_list, &fs_devices->devices);
 391                 mutex_unlock(&fs_devices->device_list_mutex);
 392
 393                 device->fs_devices = fs_devices;
 394                 fs_devices->num_devices++;
 395         } else if (!device->name || strcmp(device->name->str, path)) {
 396                 name = rcu_string_strdup(path, GFP_NOFS);
 397                 if (!name)
 398                         return -ENOMEM;
 399                 rcu_string_free(device->name);
 400                 rcu_assign_pointer(device->name, name);
 401                 if (device->missing) {
 402                         fs_devices->missing_devices--;
 403                         device->missing = 0;
 404                 }
 405         }
 406
 407         if (found_transid > fs_devices->latest_trans) {
 408                 fs_devices->latest_devid = devid;
 409                 fs_devices->latest_trans = found_transid;
 410         }
 411         *fs_devices_ret = fs_devices;
 412         return 0;
 413 }
 414
 415 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
 416 {
 417         struct btrfs_fs_devices *fs_devices;
 418         struct btrfs_device *device;
 419         struct btrfs_device *orig_dev;
 420
 421         fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 422         if (!fs_devices)
 423                 return ERR_PTR(-ENOMEM);
 424
 425         INIT_LIST_HEAD(&fs_devices->devices);
 426         INIT_LIST_HEAD(&fs_devices->alloc_list);
 427         INIT_LIST_HEAD(&fs_devices->list);
 428         mutex_init(&fs_devices->device_list_mutex);
 429         fs_devices->latest_devid = orig->latest_devid;
 430         fs_devices->latest_trans = orig->latest_trans;
 431         fs_devices->total_devices = orig->total_devices;
 432         memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
 433
 434         /* We have held the volume lock, it is safe to get the devices. */
 435         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
 436                 struct rcu_string *name;
 437
 438                 device = kzalloc(sizeof(*device), GFP_NOFS);
 439                 if (!device)
 440                         goto error;
 441
 442                 /*
 443                  * This is ok to do without rcu read locked because we hold the
 444                  * uuid mutex so nothing we touch in here is going to disappear.
 445                  */
 446                 name = rcu_string_strdup(orig_dev->name->str, GFP_NOFS);
 447                 if (!name) {
 448                         kfree(device);
 449                         goto error;
 450                 }
 451                 rcu_assign_pointer(device->name, name);
 452
 453                 device->devid = orig_dev->devid;
 454                 device->work.func = pending_bios_fn;
 455                 memcpy(device->uuid, orig_dev->uuid, sizeof(device->uuid));
 456                 spin_lock_init(&device->io_lock);
 457                 INIT_LIST_HEAD(&device->dev_list);
 458                 INIT_LIST_HEAD(&device->dev_alloc_list);
 459
 460                 list_add(&device->dev_list, &fs_devices->devices);
 461                 device->fs_devices = fs_devices;
 462                 fs_devices->num_devices++;
 463         }
 464         return fs_devices;
 465 error:
 466         free_fs_devices(fs_devices);
 467         return ERR_PTR(-ENOMEM);
 468 }
 469
 470 void btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices)
 471 {
 472         struct btrfs_device *device, *next;
 473
 474         struct block_device *latest_bdev = NULL;
 475         u64 latest_devid = 0;
 476         u64 latest_transid = 0;
 477
 478         mutex_lock(&uuid_mutex);
 479 again:
 480         /* This is the initialized path, it is safe to release the devices. */
 481         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
 482                 if (device->in_fs_metadata) {
 483                         if (!latest_transid ||
 484                             device->generation > latest_transid) {
 485                                 latest_devid = device->devid;
 486                                 latest_transid = device->generation;
 487                                 latest_bdev = device->bdev;
 488                         }
 489                         continue;
 490                 }
 491
 492                 if (device->bdev) {
 493                         blkdev_put(device->bdev, device->mode);
 494                         device->bdev = NULL;
 495                         fs_devices->open_devices--;
 496                 }
 497                 if (device->writeable) {
 498                         list_del_init(&device->dev_alloc_list);
 499                         device->writeable = 0;
 500                         fs_devices->rw_devices--;
 501                 }
 502                 list_del_init(&device->dev_list);
 503                 fs_devices->num_devices--;
 504                 rcu_string_free(device->name);
 505                 kfree(device);
 506         }
 507
 508         if (fs_devices->seed) {
 509                 fs_devices = fs_devices->seed;
 510                 goto again;
 511         }
 512
 513         fs_devices->latest_bdev = latest_bdev;
 514         fs_devices->latest_devid = latest_devid;
 515         fs_devices->latest_trans = latest_transid;
 516
 517         mutex_unlock(&uuid_mutex);
 518 }
 519
 520 static void __free_device(struct work_struct *work)
 521 {
 522         struct btrfs_device *device;
 523
 524         device = container_of(work, struct btrfs_device, rcu_work);
 525
 526         if (device->bdev)
 527                 blkdev_put(device->bdev, device->mode);
 528
 529         rcu_string_free(device->name);
 530         kfree(device);
 531 }
 532
 533 static void free_device(struct rcu_head *head)
 534 {
 535         struct btrfs_device *device;
 536
 537         device = container_of(head, struct btrfs_device, rcu);
 538
 539         INIT_WORK(&device->rcu_work, __free_device);
 540         schedule_work(&device->rcu_work);
 541 }
 542
 543 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 544 {
 545         struct btrfs_device *device;
 546
 547         if (--fs_devices->opened > 0)
 548                 return 0;
 549
 550         mutex_lock(&fs_devices->device_list_mutex);
 551         list_for_each_entry(device, &fs_devices->devices, dev_list) {
 552                 struct btrfs_device *new_device;
 553                 struct rcu_string *name;
 554
 555                 if (device->bdev)
 556                         fs_devices->open_devices--;
 557
 558                 if (device->writeable) {
 559                         list_del_init(&device->dev_alloc_list);
 560                         fs_devices->rw_devices--;
 561                 }
 562
 563                 if (device->can_discard)
 564                         fs_devices->num_can_discard--;
 565
 566                 new_device = kmalloc(sizeof(*new_device), GFP_NOFS);
 567                 BUG_ON(!new_device); /* -ENOMEM */
 568                 memcpy(new_device, device, sizeof(*new_device));
 569
 570                 /* Safe because we are under uuid_mutex */
 571                 if (device->name) {
 572                         name = rcu_string_strdup(device->name->str, GFP_NOFS);
 573                         BUG_ON(device->name && !name); /* -ENOMEM */
 574                         rcu_assign_pointer(new_device->name, name);
 575                 }
 576                 new_device->bdev = NULL;
 577                 new_device->writeable = 0;
 578                 new_device->in_fs_metadata = 0;
 579                 new_device->can_discard = 0;
 580                 list_replace_rcu(&device->dev_list, &new_device->dev_list);
 581
 582                 call_rcu(&device->rcu, free_device);
 583         }
 584         mutex_unlock(&fs_devices->device_list_mutex);
 585
 586         WARN_ON(fs_devices->open_devices);
 587         WARN_ON(fs_devices->rw_devices);
 588         fs_devices->opened = 0;
 589         fs_devices->seeding = 0;
 590
 591         return 0;
 592 }
 593
 594 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 595 {
 596         struct btrfs_fs_devices *seed_devices = NULL;
 597         int ret;
 598
 599         mutex_lock(&uuid_mutex);
 600         ret = __btrfs_close_devices(fs_devices);
 601         if (!fs_devices->opened) {
 602                 seed_devices = fs_devices->seed;
 603                 fs_devices->seed = NULL;
 604         }
 605         mutex_unlock(&uuid_mutex);
 606
 607         while (seed_devices) {
 608                 fs_devices = seed_devices;
 609                 seed_devices = fs_devices->seed;
 610                 __btrfs_close_devices(fs_devices);
 611                 free_fs_devices(fs_devices);
 612         }
 613         return ret;
 614 }
 615
 616 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 617                                 fmode_t flags, void *holder)
 618 {
 619         struct request_queue *q;
 620         struct block_device *bdev;
 621         struct list_head *head = &fs_devices->devices;
 622         struct btrfs_device *device;
 623         struct block_device *latest_bdev = NULL;
 624         struct buffer_head *bh;
 625         struct btrfs_super_block *disk_super;
 626         u64 latest_devid = 0;
 627         u64 latest_transid = 0;
 628         u64 devid;
 629         int seeding = 1;
 630         int ret = 0;
 631
 632         flags |= FMODE_EXCL;
 633
 634         list_for_each_entry(device, head, dev_list) {
 635                 if (device->bdev)
 636                         continue;
 637                 if (!device->name)
 638                         continue;
 639
 640                 bdev = blkdev_get_by_path(device->name->str, flags, holder);
 641                 if (IS_ERR(bdev)) {
 642                         printk(KERN_INFO "btrfs: open %s failed\n", device->name->str);
 643                         goto error;
 644                 }
 645                 filemap_write_and_wait(bdev->bd_inode->i_mapping);
 646                 invalidate_bdev(bdev);
 647                 set_blocksize(bdev, 4096);
 648
 649                 bh = btrfs_read_dev_super(bdev);
 650                 if (!bh)
 651                         goto error_close;
 652
 653                 disk_super = (struct btrfs_super_block *)bh->b_data;
 654                 devid = btrfs_stack_device_id(&disk_super->dev_item);
 655                 if (devid != device->devid)
 656                         goto error_brelse;
 657
 658                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
 659                            BTRFS_UUID_SIZE))
 660                         goto error_brelse;
 661
 662                 device->generation = btrfs_super_generation(disk_super);
 663                 if (!latest_transid || device->generation > latest_transid) {
 664                         latest_devid = devid;
 665                         latest_transid = device->generation;
 666                         latest_bdev = bdev;
 667                 }
 668
 669                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
 670                         device->writeable = 0;
 671                 } else {
 672                         device->writeable = !bdev_read_only(bdev);
 673                         seeding = 0;
 674                 }
 675
 676                 q = bdev_get_queue(bdev);
 677                 if (blk_queue_discard(q)) {
 678                         device->can_discard = 1;
 679                         fs_devices->num_can_discard++;
 680                 }
 681
 682                 device->bdev = bdev;
 683                 device->in_fs_metadata = 0;
 684                 device->mode = flags;
 685
 686                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
 687                         fs_devices->rotating = 1;
 688
 689                 fs_devices->open_devices++;
 690                 if (device->writeable) {
 691                         fs_devices->rw_devices++;
 692                         list_add(&device->dev_alloc_list,
 693                                  &fs_devices->alloc_list);
 694                 }
 695                 brelse(bh);
 696                 continue;
 697
 698 error_brelse:
 699                 brelse(bh);
 700 error_close:
 701                 blkdev_put(bdev, flags);
 702 error:
 703                 continue;
 704         }
 705         if (fs_devices->open_devices == 0) {
 706                 ret = -EINVAL;
 707                 goto out;
 708         }
 709         fs_devices->seeding = seeding;
 710         fs_devices->opened = 1;
 711         fs_devices->latest_bdev = latest_bdev;
 712         fs_devices->latest_devid = latest_devid;
 713         fs_devices->latest_trans = latest_transid;
 714         fs_devices->total_rw_bytes = 0;
 715 out:
 716         return ret;
 717 }
 718
 719 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 720                        fmode_t flags, void *holder)
 721 {
 722         int ret;
 723
 724         mutex_lock(&uuid_mutex);
 725         if (fs_devices->opened) {
 726                 fs_devices->opened++;
 727                 ret = 0;
 728         } else {
 729                 ret = __btrfs_open_devices(fs_devices, flags, holder);
 730         }
 731         mutex_unlock(&uuid_mutex);
 732         return ret;
 733 }
 734
 735 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 736                           struct btrfs_fs_devices **fs_devices_ret)
 737 {
 738         struct btrfs_super_block *disk_super;
 739         struct block_device *bdev;
 740         struct buffer_head *bh;
 741         int ret;
 742         u64 devid;
 743         u64 transid;
 744         u64 total_devices;
 745
 746         flags |= FMODE_EXCL;
 747         bdev = blkdev_get_by_path(path, flags, holder);
 748
 749         if (IS_ERR(bdev)) {
 750                 ret = PTR_ERR(bdev);
 751                 goto error;
 752         }
 753
 754         mutex_lock(&uuid_mutex);
 755         ret = set_blocksize(bdev, 4096);
 756         if (ret)
 757                 goto error_close;
 758         bh = btrfs_read_dev_super(bdev);
 759         if (!bh) {
 760                 ret = -EINVAL;
 761                 goto error_close;
 762         }
 763         disk_super = (struct btrfs_super_block *)bh->b_data;
 764         devid = btrfs_stack_device_id(&disk_super->dev_item);
 765         transid = btrfs_super_generation(disk_super);
 766         total_devices = btrfs_super_num_devices(disk_super);
 767         if (disk_super->label[0])
 768                 printk(KERN_INFO "device label %s ", disk_super->label);
 769         else
 770                 printk(KERN_INFO "device fsid %pU ", disk_super->fsid);
 771         printk(KERN_CONT "devid %llu transid %llu %s\n",
 772                (unsigned long long)devid, (unsigned long long)transid, path);
 773         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
 774         if (!ret && fs_devices_ret)
 775                 (*fs_devices_ret)->total_devices = total_devices;
 776         brelse(bh);
 777 error_close:
 778         mutex_unlock(&uuid_mutex);
 779         blkdev_put(bdev, flags);
 780 error:
 781         return ret;
 782 }
 783
 784 /* helper to account the used device space in the range */
 785 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
 786                                    u64 end, u64 *length)
 787 {
 788         struct btrfs_key key;
 789         struct btrfs_root *root = device->dev_root;
 790         struct btrfs_dev_extent *dev_extent;
 791         struct btrfs_path *path;
 792         u64 extent_end;
 793         int ret;
 794         int slot;
 795         struct extent_buffer *l;
 796
 797         *length = 0;
 798
 799         if (start >= device->total_bytes)
 800                 return 0;
 801
 802         path = btrfs_alloc_path();
 803         if (!path)
 804                 return -ENOMEM;
 805         path->reada = 2;
 806
 807         key.objectid = device->devid;
 808         key.offset = start;
 809         key.type = BTRFS_DEV_EXTENT_KEY;
 810
 811         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 812         if (ret < 0)
 813                 goto out;
 814         if (ret > 0) {
 815                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
 816                 if (ret < 0)
 817                         goto out;
 818         }
 819
 820         while (1) {
 821                 l = path->nodes[0];
 822                 slot = path->slots[0];
 823                 if (slot >= btrfs_header_nritems(l)) {
 824                         ret = btrfs_next_leaf(root, path);
 825                         if (ret == 0)
 826                                 continue;
 827                         if (ret < 0)
 828                                 goto out;
 829
 830                         break;
 831                 }
 832                 btrfs_item_key_to_cpu(l, &key, slot);
 833
 834                 if (key.objectid < device->devid)
 835                         goto next;
 836
 837                 if (key.objectid > device->devid)
 838                         break;
 839
 840                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
 841                         goto next;
 842
 843                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
 844                 extent_end = key.offset + btrfs_dev_extent_length(l,
 845                                                                   dev_extent);
 846                 if (key.offset <= start && extent_end > end) {
 847                         *length = end - start + 1;
 848                         break;
 849                 } else if (key.offset <= start && extent_end > start)
 850                         *length += extent_end - start;
 851                 else if (key.offset > start && extent_end <= end)
 852                         *length += extent_end - key.offset;
 853                 else if (key.offset > start && key.offset <= end) {
 854                         *length += end - key.offset + 1;
 855                         break;
 856                 } else if (key.offset > end)
 857                         break;
 858
 859 next:
 860                 path->slots[0]++;
 861         }
 862         ret = 0;
 863 out:
 864         btrfs_free_path(path);
 865         return ret;
 866 }
 867
 868 /*
 869  * find_free_dev_extent - find free space in the specified device
 870  * @device:     the device which we search the free space in
 871  * @num_bytes:  the size of the free space that we need
 872  * @start:      store the start of the free space.
 873  * @len:        the size of the free space. that we find, or the size of the max
 874  *              free space if we don't find suitable free space
 875  *
 876  * this uses a pretty simple search, the expectation is that it is
 877  * called very infrequently and that a given device has a small number
 878  * of extents
 879  *
 880  * @start is used to store the start of the free space if we find. But if we
 881  * don't find suitable free space, it will be used to store the start position
 882  * of the max free space.
 883  *
 884  * @len is used to store the size of the free space that we find.
 885  * But if we don't find suitable free space, it is used to store the size of
 886  * the max free space.
 887  */
 888 int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
 889                          u64 *start, u64 *len)
 890 {
 891         struct btrfs_key key;
 892         struct btrfs_root *root = device->dev_root;
 893         struct btrfs_dev_extent *dev_extent;
 894         struct btrfs_path *path;
 895         u64 hole_size;
 896         u64 max_hole_start;
 897         u64 max_hole_size;
 898         u64 extent_end;
 899         u64 search_start;
 900         u64 search_end = device->total_bytes;
 901         int ret;
 902         int slot;
 903         struct extent_buffer *l;
 904
 905         /* FIXME use last free of some kind */
 906
 907         /* we don't want to overwrite the superblock on the drive,
 908          * so we make sure to start at an offset of at least 1MB
 909          */
 910         search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
 911
 912         max_hole_start = search_start;
 913         max_hole_size = 0;
 914         hole_size = 0;
 915
 916         if (search_start >= search_end) {
 917                 ret = -ENOSPC;
 918                 goto error;
 919         }
 920
 921         path = btrfs_alloc_path();
 922         if (!path) {
 923                 ret = -ENOMEM;
 924                 goto error;
 925         }
 926         path->reada = 2;
 927
 928         key.objectid = device->devid;
 929         key.offset = search_start;
 930         key.type = BTRFS_DEV_EXTENT_KEY;
 931
 932         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 933         if (ret < 0)
 934                 goto out;
 935         if (ret > 0) {
 936                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
 937                 if (ret < 0)
 938                         goto out;
 939         }
 940
 941         while (1) {
 942                 l = path->nodes[0];
 943                 slot = path->slots[0];
 944                 if (slot >= btrfs_header_nritems(l)) {
 945                         ret = btrfs_next_leaf(root, path);
 946                         if (ret == 0)
 947                                 continue;
 948                         if (ret < 0)
 949                                 goto out;
 950
 951                         break;
 952                 }
 953                 btrfs_item_key_to_cpu(l, &key, slot);
 954
 955                 if (key.objectid < device->devid)
 956                         goto next;
 957
 958                 if (key.objectid > device->devid)
 959                         break;
 960
 961                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
 962                         goto next;
 963
 964                 if (key.offset > search_start) {
 965                         hole_size = key.offset - search_start;
 966
 967                         if (hole_size > max_hole_size) {
 968                                 max_hole_start = search_start;
 969                                 max_hole_size = hole_size;
 970                         }
 971
 972                         /*
 973                          * If this free space is greater than which we need,
 974                          * it must be the max free space that we have found
 975                          * until now, so max_hole_start must point to the start
 976                          * of this free space and the length of this free space
 977                          * is stored in max_hole_size. Thus, we return
 978                          * max_hole_start and max_hole_size and go back to the
 979                          * caller.
 980                          */
 981                         if (hole_size >= num_bytes) {
 982                                 ret = 0;
 983                                 goto out;
 984                         }
 985                 }
 986
 987                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
 988                 extent_end = key.offset + btrfs_dev_extent_length(l,
 989                                                                   dev_extent);
 990                 if (extent_end > search_start)
 991                         search_start = extent_end;
 992 next:
 993                 path->slots[0]++;
 994                 cond_resched();
 995         }
 996
 997         /*
 998          * At this point, search_start should be the end of
 999          * allocated dev extents, and when shrinking the device,
1000          * search_end may be smaller than search_start.
1001          */
1002         if (search_end > search_start)
1003                 hole_size = search_end - search_start;
1004
1005         if (hole_size > max_hole_size) {
1006                 max_hole_start = search_start;
1007                 max_hole_size = hole_size;
1008         }
1009
1010         /* See above. */
1011         if (hole_size < num_bytes)
1012                 ret = -ENOSPC;
1013         else
1014                 ret = 0;
1015
1016 out:
1017         btrfs_free_path(path);
1018 error:
1019         *start = max_hole_start;
1020         if (len)
1021                 *len = max_hole_size;
1022         return ret;
1023 }
1024
1025 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
1026                           struct btrfs_device *device,
1027                           u64 start)
1028 {
1029         int ret;
1030         struct btrfs_path *path;
1031         struct btrfs_root *root = device->dev_root;
1032         struct btrfs_key key;
1033         struct btrfs_key found_key;
1034         struct extent_buffer *leaf = NULL;
1035         struct btrfs_dev_extent *extent = NULL;
1036
1037         path = btrfs_alloc_path();
1038         if (!path)
1039                 return -ENOMEM;
1040
1041         key.objectid = device->devid;
1042         key.offset = start;
1043         key.type = BTRFS_DEV_EXTENT_KEY;
1044 again:
1045         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1046         if (ret > 0) {
1047                 ret = btrfs_previous_item(root, path, key.objectid,
1048                                           BTRFS_DEV_EXTENT_KEY);
1049                 if (ret)
1050                         goto out;
1051                 leaf = path->nodes[0];
1052                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1053                 extent = btrfs_item_ptr(leaf, path->slots[0],
1054                                         struct btrfs_dev_extent);
1055                 BUG_ON(found_key.offset > start || found_key.offset +
1056                        btrfs_dev_extent_length(leaf, extent) < start);
1057                 key = found_key;
1058                 btrfs_release_path(path);
1059                 goto again;
1060         } else if (ret == 0) {
1061                 leaf = path->nodes[0];
1062                 extent = btrfs_item_ptr(leaf, path->slots[0],
1063                                         struct btrfs_dev_extent);
1064         } else {
1065                 btrfs_error(root->fs_info, ret, "Slot search failed");
1066                 goto out;
1067         }
1068
1069         if (device->bytes_used > 0) {
1070                 u64 len = btrfs_dev_extent_length(leaf, extent);
1071                 device->bytes_used -= len;
1072                 spin_lock(&root->fs_info->free_chunk_lock);
1073                 root->fs_info->free_chunk_space += len;
1074                 spin_unlock(&root->fs_info->free_chunk_lock);
1075         }
1076         ret = btrfs_del_item(trans, root, path);
1077         if (ret) {
1078                 btrfs_error(root->fs_info, ret,
1079                             "Failed to remove dev extent item");
1080         }
1081 out:
1082         btrfs_free_path(path);
1083         return ret;
1084 }
1085
1086 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
1087                            struct btrfs_device *device,
1088                            u64 chunk_tree, u64 chunk_objectid,
1089                            u64 chunk_offset, u64 start, u64 num_bytes)
1090 {
1091         int ret;
1092         struct btrfs_path *path;
1093         struct btrfs_root *root = device->dev_root;
1094         struct btrfs_dev_extent *extent;
1095         struct extent_buffer *leaf;
1096         struct btrfs_key key;
1097
1098         WARN_ON(!device->in_fs_metadata);
1099         path = btrfs_alloc_path();
1100         if (!path)
1101                 return -ENOMEM;
1102
1103         key.objectid = device->devid;
1104         key.offset = start;
1105         key.type = BTRFS_DEV_EXTENT_KEY;
1106         ret = btrfs_insert_empty_item(trans, root, path, &key,
1107                                       sizeof(*extent));
1108         if (ret)
1109                 goto out;
1110
1111         leaf = path->nodes[0];
1112         extent = btrfs_item_ptr(leaf, path->slots[0],
1113                                 struct btrfs_dev_extent);
1114         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
1115         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
1116         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1117
1118         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
1119                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
1120                     BTRFS_UUID_SIZE);
1121
1122         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1123         btrfs_mark_buffer_dirty(leaf);
1124 out:
1125         btrfs_free_path(path);
1126         return ret;
1127 }
1128
1129 static noinline int find_next_chunk(struct btrfs_root *root,
1130                                     u64 objectid, u64 *offset)
1131 {
1132         struct btrfs_path *path;
1133         int ret;
1134         struct btrfs_key key;
1135         struct btrfs_chunk *chunk;
1136         struct btrfs_key found_key;
1137
1138         path = btrfs_alloc_path();
1139         if (!path)
1140                 return -ENOMEM;
1141
1142         key.objectid = objectid;
1143         key.offset = (u64)-1;
1144         key.type = BTRFS_CHUNK_ITEM_KEY;
1145
1146         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1147         if (ret < 0)
1148                 goto error;
1149
1150         BUG_ON(ret == 0); /* Corruption */
1151
1152         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
1153         if (ret) {
1154                 *offset = 0;
1155         } else {
1156                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1157                                       path->slots[0]);
1158                 if (found_key.objectid != objectid)
1159                         *offset = 0;
1160                 else {
1161                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
1162                                                struct btrfs_chunk);
1163                         *offset = found_key.offset +
1164                                 btrfs_chunk_length(path->nodes[0], chunk);
1165                 }
1166         }
1167         ret = 0;
1168 error:
1169         btrfs_free_path(path);
1170         return ret;
1171 }
1172
1173 static noinline int find_next_devid(struct btrfs_root *root, u64 *objectid)
1174 {
1175         int ret;
1176         struct btrfs_key key;
1177         struct btrfs_key found_key;
1178         struct btrfs_path *path;
1179
1180         root = root->fs_info->chunk_root;
1181
1182         path = btrfs_alloc_path();
1183         if (!path)
1184                 return -ENOMEM;
1185
1186         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1187         key.type = BTRFS_DEV_ITEM_KEY;
1188         key.offset = (u64)-1;
1189
1190         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1191         if (ret < 0)
1192                 goto error;
1193
1194         BUG_ON(ret == 0); /* Corruption */
1195
1196         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
1197                                   BTRFS_DEV_ITEM_KEY);
1198         if (ret) {
1199                 *objectid = 1;
1200         } else {
1201                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1202                                       path->slots[0]);
1203                 *objectid = found_key.offset + 1;
1204         }
1205         ret = 0;
1206 error:
1207         btrfs_free_path(path);
1208         return ret;
1209 }
1210
1211 /*
1212  * the device information is stored in the chunk root
1213  * the btrfs_device struct should be fully filled in
1214  */
1215 int btrfs_add_device(struct btrfs_trans_handle *trans,
1216                      struct btrfs_root *root,
1217                      struct btrfs_device *device)
1218 {
1219         int ret;
1220         struct btrfs_path *path;
1221         struct btrfs_dev_item *dev_item;
1222         struct extent_buffer *leaf;
1223         struct btrfs_key key;
1224         unsigned long ptr;
1225
1226         root = root->fs_info->chunk_root;
1227
1228         path = btrfs_alloc_path();
1229         if (!path)
1230                 return -ENOMEM;
1231
1232         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1233         key.type = BTRFS_DEV_ITEM_KEY;
1234         key.offset = device->devid;
1235
1236         ret = btrfs_insert_empty_item(trans, root, path, &key,
1237                                       sizeof(*dev_item));
1238         if (ret)
1239                 goto out;
1240
1241         leaf = path->nodes[0];
1242         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1243
1244         btrfs_set_device_id(leaf, dev_item, device->devid);
1245         btrfs_set_device_generation(leaf, dev_item, 0);
1246         btrfs_set_device_type(leaf, dev_item, device->type);
1247         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1248         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1249         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1250         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1251         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1252         btrfs_set_device_group(leaf, dev_item, 0);
1253         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1254         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1255         btrfs_set_device_start_offset(leaf, dev_item, 0);
1256
1257         ptr = (unsigned long)btrfs_device_uuid(dev_item);
1258         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1259         ptr = (unsigned long)btrfs_device_fsid(dev_item);
1260         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1261         btrfs_mark_buffer_dirty(leaf);
1262
1263         ret = 0;
1264 out:
1265         btrfs_free_path(path);
1266         return ret;
1267 }
1268
1269 static int btrfs_rm_dev_item(struct btrfs_root *root,
1270                              struct btrfs_device *device)
1271 {
1272         int ret;
1273         struct btrfs_path *path;
1274         struct btrfs_key key;
1275         struct btrfs_trans_handle *trans;
1276
1277         root = root->fs_info->chunk_root;
1278
1279         path = btrfs_alloc_path();
1280         if (!path)
1281                 return -ENOMEM;
1282
1283         trans = btrfs_start_transaction(root, 0);
1284         if (IS_ERR(trans)) {
1285                 btrfs_free_path(path);
1286                 return PTR_ERR(trans);
1287         }
1288         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1289         key.type = BTRFS_DEV_ITEM_KEY;
1290         key.offset = device->devid;
1291         lock_chunks(root);
1292
1293         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1294         if (ret < 0)
1295                 goto out;
1296
1297         if (ret > 0) {
1298                 ret = -ENOENT;
1299                 goto out;
1300         }
1301
1302         ret = btrfs_del_item(trans, root, path);
1303         if (ret)
1304                 goto out;
1305 out:
1306         btrfs_free_path(path);
1307         unlock_chunks(root);
1308         btrfs_commit_transaction(trans, root);
1309         return ret;
1310 }
1311
1312 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1313 {
1314         struct btrfs_device *device;
1315         struct btrfs_device *next_device;
1316         struct block_device *bdev;
1317         struct buffer_head *bh = NULL;
1318         struct btrfs_super_block *disk_super;
1319         struct btrfs_fs_devices *cur_devices;
1320         u64 all_avail;
1321         u64 devid;
1322         u64 num_devices;
1323         u8 *dev_uuid;
1324         int ret = 0;
1325         bool clear_super = false;
1326
1327         mutex_lock(&uuid_mutex);
1328
1329         all_avail = root->fs_info->avail_data_alloc_bits |
1330                 root->fs_info->avail_system_alloc_bits |
1331                 root->fs_info->avail_metadata_alloc_bits;
1332
1333         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) &&
1334             root->fs_info->fs_devices->num_devices <= 4) {
1335                 printk(KERN_ERR "btrfs: unable to go below four devices "
1336                        "on raid10\n");
1337                 ret = -EINVAL;
1338                 goto out;
1339         }
1340
1341         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) &&
1342             root->fs_info->fs_devices->num_devices <= 2) {
1343                 printk(KERN_ERR "btrfs: unable to go below two "
1344                        "devices on raid1\n");
1345                 ret = -EINVAL;
1346                 goto out;
1347         }
1348
1349         if (strcmp(device_path, "missing") == 0) {
1350                 struct list_head *devices;
1351                 struct btrfs_device *tmp;
1352
1353                 device = NULL;
1354                 devices = &root->fs_info->fs_devices->devices;
1355                 /*
1356                  * It is safe to read the devices since the volume_mutex
1357                  * is held.
1358                  */
1359                 list_for_each_entry(tmp, devices, dev_list) {
1360                         if (tmp->in_fs_metadata && !tmp->bdev) {
1361                                 device = tmp;
1362                                 break;
1363                         }
1364                 }
1365                 bdev = NULL;
1366                 bh = NULL;
1367                 disk_super = NULL;
1368                 if (!device) {
1369                         printk(KERN_ERR "btrfs: no missing devices found to "
1370                                "remove\n");
1371                         goto out;
1372                 }
1373         } else {
1374                 bdev = blkdev_get_by_path(device_path, FMODE_READ | FMODE_EXCL,
1375                                           root->fs_info->bdev_holder);
1376                 if (IS_ERR(bdev)) {
1377                         ret = PTR_ERR(bdev);
1378                         goto out;
1379                 }
1380
1381                 set_blocksize(bdev, 4096);
1382                 invalidate_bdev(bdev);
1383                 bh = btrfs_read_dev_super(bdev);
1384                 if (!bh) {
1385                         ret = -EINVAL;
1386                         goto error_close;
1387                 }
1388                 disk_super = (struct btrfs_super_block *)bh->b_data;
1389                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1390                 dev_uuid = disk_super->dev_item.uuid;
1391                 device = btrfs_find_device(root, devid, dev_uuid,
1392                                            disk_super->fsid);
1393                 if (!device) {
1394                         ret = -ENOENT;
1395                         goto error_brelse;
1396                 }
1397         }
1398
1399         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1400                 printk(KERN_ERR "btrfs: unable to remove the only writeable "
1401                        "device\n");
1402                 ret = -EINVAL;
1403                 goto error_brelse;
1404         }
1405
1406         if (device->writeable) {
1407                 lock_chunks(root);
1408                 list_del_init(&device->dev_alloc_list);
1409                 unlock_chunks(root);
1410                 root->fs_info->fs_devices->rw_devices--;
1411                 clear_super = true;
1412         }
1413
1414         ret = btrfs_shrink_device(device, 0);
1415         if (ret)
1416                 goto error_undo;
1417
1418         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1419         if (ret)
1420                 goto error_undo;
1421
1422         spin_lock(&root->fs_info->free_chunk_lock);
1423         root->fs_info->free_chunk_space = device->total_bytes -
1424                 device->bytes_used;
1425         spin_unlock(&root->fs_info->free_chunk_lock);
1426
1427         device->in_fs_metadata = 0;
1428         btrfs_scrub_cancel_dev(root, device);
1429
1430         /*
1431          * the device list mutex makes sure that we don't change
1432          * the device list while someone else is writing out all
1433          * the device supers.
1434          */
1435
1436         cur_devices = device->fs_devices;
1437         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1438         list_del_rcu(&device->dev_list);
1439
1440         device->fs_devices->num_devices--;
1441         device->fs_devices->total_devices--;
1442
1443         if (device->missing)
1444                 root->fs_info->fs_devices->missing_devices--;
1445
1446         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1447                                  struct btrfs_device, dev_list);
1448         if (device->bdev == root->fs_info->sb->s_bdev)
1449                 root->fs_info->sb->s_bdev = next_device->bdev;
1450         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1451                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1452
1453         if (device->bdev)
1454                 device->fs_devices->open_devices--;
1455
1456         call_rcu(&device->rcu, free_device);
1457         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1458
1459         num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
1460         btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
1461
1462         if (cur_devices->open_devices == 0) {
1463                 struct btrfs_fs_devices *fs_devices;
1464                 fs_devices = root->fs_info->fs_devices;
1465                 while (fs_devices) {
1466                         if (fs_devices->seed == cur_devices)
1467                                 break;
1468                         fs_devices = fs_devices->seed;
1469                 }
1470                 fs_devices->seed = cur_devices->seed;
1471                 cur_devices->seed = NULL;
1472                 lock_chunks(root);
1473                 __btrfs_close_devices(cur_devices);
1474                 unlock_chunks(root);
1475                 free_fs_devices(cur_devices);
1476         }
1477
1478         root->fs_info->num_tolerated_disk_barrier_failures =
1479                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1480
1481         /*
1482          * at this point, the device is zero sized.  We want to
1483          * remove it from the devices list and zero out the old super
1484          */
1485         if (clear_super) {
1486                 /* make sure this device isn't detected as part of
1487                  * the FS anymore
1488                  */
1489                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1490                 set_buffer_dirty(bh);
1491                 sync_dirty_buffer(bh);
1492         }
1493
1494         ret = 0;
1495
1496 error_brelse:
1497         brelse(bh);
1498 error_close:
1499         if (bdev)
1500                 blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
1501 out:
1502         mutex_unlock(&uuid_mutex);
1503         return ret;
1504 error_undo:
1505         if (device->writeable) {
1506                 lock_chunks(root);
1507                 list_add(&device->dev_alloc_list,
1508                          &root->fs_info->fs_devices->alloc_list);
1509                 unlock_chunks(root);
1510                 root->fs_info->fs_devices->rw_devices++;
1511         }
1512         goto error_brelse;
1513 }
1514
1515 /*
1516  * does all the dirty work required for changing file system's UUID.
1517  */
1518 static int btrfs_prepare_sprout(struct btrfs_root *root)
1519 {
1520         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
1521         struct btrfs_fs_devices *old_devices;
1522         struct btrfs_fs_devices *seed_devices;
1523         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
1524         struct btrfs_device *device;
1525         u64 super_flags;
1526
1527         BUG_ON(!mutex_is_locked(&uuid_mutex));
1528         if (!fs_devices->seeding)
1529                 return -EINVAL;
1530
1531         seed_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1532         if (!seed_devices)
1533                 return -ENOMEM;
1534
1535         old_devices = clone_fs_devices(fs_devices);
1536         if (IS_ERR(old_devices)) {
1537                 kfree(seed_devices);
1538                 return PTR_ERR(old_devices);
1539         }
1540
1541         list_add(&old_devices->list, &fs_uuids);
1542
1543         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
1544         seed_devices->opened = 1;
1545         INIT_LIST_HEAD(&seed_devices->devices);
1546         INIT_LIST_HEAD(&seed_devices->alloc_list);
1547         mutex_init(&seed_devices->device_list_mutex);
1548
1549         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1550         list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
1551                               synchronize_rcu);
1552         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1553
1554         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
1555         list_for_each_entry(device, &seed_devices->devices, dev_list) {
1556                 device->fs_devices = seed_devices;
1557         }
1558
1559         fs_devices->seeding = 0;
1560         fs_devices->num_devices = 0;
1561         fs_devices->open_devices = 0;
1562         fs_devices->total_devices = 0;
1563         fs_devices->seed = seed_devices;
1564
1565         generate_random_uuid(fs_devices->fsid);
1566         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1567         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1568         super_flags = btrfs_super_flags(disk_super) &
1569                       ~BTRFS_SUPER_FLAG_SEEDING;
1570         btrfs_set_super_flags(disk_super, super_flags);
1571
1572         return 0;
1573 }
1574
1575 /*
1576  * strore the expected generation for seed devices in device items.
1577  */
1578 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
1579                                struct btrfs_root *root)
1580 {
1581         struct btrfs_path *path;
1582         struct extent_buffer *leaf;
1583         struct btrfs_dev_item *dev_item;
1584         struct btrfs_device *device;
1585         struct btrfs_key key;
1586         u8 fs_uuid[BTRFS_UUID_SIZE];
1587         u8 dev_uuid[BTRFS_UUID_SIZE];
1588         u64 devid;
1589         int ret;
1590
1591         path = btrfs_alloc_path();
1592         if (!path)
1593                 return -ENOMEM;
1594
1595         root = root->fs_info->chunk_root;
1596         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1597         key.offset = 0;
1598         key.type = BTRFS_DEV_ITEM_KEY;
1599
1600         while (1) {
1601                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1602                 if (ret < 0)
1603                         goto error;
1604
1605                 leaf = path->nodes[0];
1606 next_slot:
1607                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1608                         ret = btrfs_next_leaf(root, path);
1609                         if (ret > 0)
1610                                 break;
1611                         if (ret < 0)
1612                                 goto error;
1613                         leaf = path->nodes[0];
1614                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1615                         btrfs_release_path(path);
1616                         continue;
1617                 }
1618
1619                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1620                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
1621                     key.type != BTRFS_DEV_ITEM_KEY)
1622                         break;
1623
1624                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
1625                                           struct btrfs_dev_item);
1626                 devid = btrfs_device_id(leaf, dev_item);
1627                 read_extent_buffer(leaf, dev_uuid,
1628                                    (unsigned long)btrfs_device_uuid(dev_item),
1629                                    BTRFS_UUID_SIZE);
1630                 read_extent_buffer(leaf, fs_uuid,
1631                                    (unsigned long)btrfs_device_fsid(dev_item),
1632                                    BTRFS_UUID_SIZE);
1633                 device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
1634                 BUG_ON(!device); /* Logic error */
1635
1636                 if (device->fs_devices->seeding) {
1637                         btrfs_set_device_generation(leaf, dev_item,
1638                                                     device->generation);
1639                         btrfs_mark_buffer_dirty(leaf);
1640                 }
1641
1642                 path->slots[0]++;
1643                 goto next_slot;
1644         }
1645         ret = 0;
1646 error:
1647         btrfs_free_path(path);
1648         return ret;
1649 }
1650
1651 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
1652 {
1653         struct request_queue *q;
1654         struct btrfs_trans_handle *trans;
1655         struct btrfs_device *device;
1656         struct block_device *bdev;
1657         struct list_head *devices;
1658         struct super_block *sb = root->fs_info->sb;
1659         struct rcu_string *name;
1660         u64 total_bytes;
1661         int seeding_dev = 0;
1662         int ret = 0;
1663
1664         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
1665                 return -EROFS;
1666
1667         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
1668                                   root->fs_info->bdev_holder);
1669         if (IS_ERR(bdev))
1670                 return PTR_ERR(bdev);
1671
1672         if (root->fs_info->fs_devices->seeding) {
1673                 seeding_dev = 1;
1674                 down_write(&sb->s_umount);
1675                 mutex_lock(&uuid_mutex);
1676         }
1677
1678         filemap_write_and_wait(bdev->bd_inode->i_mapping);
1679
1680         devices = &root->fs_info->fs_devices->devices;
1681         /*
1682          * we have the volume lock, so we don't need the extra
1683          * device list mutex while reading the list here.
1684          */
1685         list_for_each_entry(device, devices, dev_list) {
1686                 if (device->bdev == bdev) {
1687                         ret = -EEXIST;
1688                         goto error;
1689                 }
1690         }
1691
1692         device = kzalloc(sizeof(*device), GFP_NOFS);
1693         if (!device) {
1694                 /* we can safely leave the fs_devices entry around */
1695                 ret = -ENOMEM;
1696                 goto error;
1697         }
1698
1699         name = rcu_string_strdup(device_path, GFP_NOFS);
1700         if (!name) {
1701                 kfree(device);
1702                 ret = -ENOMEM;
1703                 goto error;
1704         }
1705         rcu_assign_pointer(device->name, name);
1706
1707         ret = find_next_devid(root, &device->devid);
1708         if (ret) {
1709                 rcu_string_free(device->name);
1710                 kfree(device);
1711                 goto error;
1712         }
1713
1714         trans = btrfs_start_transaction(root, 0);
1715         if (IS_ERR(trans)) {
1716                 rcu_string_free(device->name);
1717                 kfree(device);
1718                 ret = PTR_ERR(trans);
1719                 goto error;
1720         }
1721
1722         lock_chunks(root);
1723
1724         q = bdev_get_queue(bdev);
1725         if (blk_queue_discard(q))
1726                 device->can_discard = 1;
1727         device->writeable = 1;
1728         device->work.func = pending_bios_fn;
1729         generate_random_uuid(device->uuid);
1730         spin_lock_init(&device->io_lock);
1731         device->generation = trans->transid;
1732         device->io_width = root->sectorsize;
1733         device->io_align = root->sectorsize;
1734         device->sector_size = root->sectorsize;
1735         device->total_bytes = i_size_read(bdev->bd_inode);
1736         device->disk_total_bytes = device->total_bytes;
1737         device->dev_root = root->fs_info->dev_root;
1738         device->bdev = bdev;
1739         device->in_fs_metadata = 1;
1740         device->mode = FMODE_EXCL;
1741         set_blocksize(device->bdev, 4096);
1742
1743         if (seeding_dev) {
1744                 sb->s_flags &= ~MS_RDONLY;
1745                 ret = btrfs_prepare_sprout(root);
1746                 BUG_ON(ret); /* -ENOMEM */
1747         }
1748
1749         device->fs_devices = root->fs_info->fs_devices;
1750
1751         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1752         list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
1753         list_add(&device->dev_alloc_list,
1754                  &root->fs_info->fs_devices->alloc_list);
1755         root->fs_info->fs_devices->num_devices++;
1756         root->fs_info->fs_devices->open_devices++;
1757         root->fs_info->fs_devices->rw_devices++;
1758         root->fs_info->fs_devices->total_devices++;
1759         if (device->can_discard)
1760                 root->fs_info->fs_devices->num_can_discard++;
1761         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
1762
1763         spin_lock(&root->fs_info->free_chunk_lock);
1764         root->fs_info->free_chunk_space += device->total_bytes;
1765         spin_unlock(&root->fs_info->free_chunk_lock);
1766
1767         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
1768                 root->fs_info->fs_devices->rotating = 1;
1769
1770         total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
1771         btrfs_set_super_total_bytes(root->fs_info->super_copy,
1772                                     total_bytes + device->total_bytes);
1773
1774         total_bytes = btrfs_super_num_devices(root->fs_info->super_copy);
1775         btrfs_set_super_num_devices(root->fs_info->super_copy,
1776                                     total_bytes + 1);
1777         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1778
1779         if (seeding_dev) {
1780                 ret = init_first_rw_device(trans, root, device);
1781                 if (ret) {
1782                         btrfs_abort_transaction(trans, root, ret);
1783                         goto error_trans;
1784                 }
1785                 ret = btrfs_finish_sprout(trans, root);
1786                 if (ret) {
1787                         btrfs_abort_transaction(trans, root, ret);
1788                         goto error_trans;
1789                 }
1790         } else {
1791                 ret = btrfs_add_device(trans, root, device);
1792                 if (ret) {
1793                         btrfs_abort_transaction(trans, root, ret);
1794                         goto error_trans;
1795                 }
1796         }
1797
1798         /*
1799          * we've got more storage, clear any full flags on the space
1800          * infos
1801          */
1802         btrfs_clear_space_info_full(root->fs_info);
1803
1804         unlock_chunks(root);
1805         root->fs_info->num_tolerated_disk_barrier_failures =
1806                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1807         ret = btrfs_commit_transaction(trans, root);
1808
1809         if (seeding_dev) {
1810                 mutex_unlock(&uuid_mutex);
1811                 up_write(&sb->s_umount);
1812
1813                 if (ret) /* transaction commit */
1814                         return ret;
1815
1816                 ret = btrfs_relocate_sys_chunks(root);
1817                 if (ret < 0)
1818                         btrfs_error(root->fs_info, ret,
1819                                     "Failed to relocate sys chunks after "
1820                                     "device initialization. This can be fixed "
1821                                     "using the \"btrfs balance\" command.");
1822                 trans = btrfs_attach_transaction(root);
1823                 if (IS_ERR(trans)) {
1824                         if (PTR_ERR(trans) == -ENOENT)
1825                                 return 0;
1826                         return PTR_ERR(trans);
1827                 }
1828                 ret = btrfs_commit_transaction(trans, root);
1829         }
1830
1831         return ret;
1832
1833 error_trans:
1834         unlock_chunks(root);
1835         btrfs_end_transaction(trans, root);
1836         rcu_string_free(device->name);
1837         kfree(device);
1838 error:
1839         blkdev_put(bdev, FMODE_EXCL);
1840         if (seeding_dev) {
1841                 mutex_unlock(&uuid_mutex);
1842                 up_write(&sb->s_umount);
1843         }
1844         return ret;
1845 }
1846
1847 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
1848                                         struct btrfs_device *device)
1849 {
1850         int ret;
1851         struct btrfs_path *path;
1852         struct btrfs_root *root;
1853         struct btrfs_dev_item *dev_item;
1854         struct extent_buffer *leaf;
1855         struct btrfs_key key;
1856
1857         root = device->dev_root->fs_info->chunk_root;
1858
1859         path = btrfs_alloc_path();
1860         if (!path)
1861                 return -ENOMEM;
1862
1863         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1864         key.type = BTRFS_DEV_ITEM_KEY;
1865         key.offset = device->devid;
1866
1867         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1868         if (ret < 0)
1869                 goto out;
1870
1871         if (ret > 0) {
1872                 ret = -ENOENT;
1873                 goto out;
1874         }
1875
1876         leaf = path->nodes[0];
1877         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1878
1879         btrfs_set_device_id(leaf, dev_item, device->devid);
1880         btrfs_set_device_type(leaf, dev_item, device->type);
1881         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1882         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1883         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1884         btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
1885         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1886         btrfs_mark_buffer_dirty(leaf);
1887
1888 out:
1889         btrfs_free_path(path);
1890         return ret;
1891 }
1892
1893 static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
1894                       struct btrfs_device *device, u64 new_size)
1895 {
1896         struct btrfs_super_block *super_copy =
1897                 device->dev_root->fs_info->super_copy;
1898         u64 old_total = btrfs_super_total_bytes(super_copy);
1899         u64 diff = new_size - device->total_bytes;
1900
1901         if (!device->writeable)
1902                 return -EACCES;
1903         if (new_size <= device->total_bytes)
1904                 return -EINVAL;
1905
1906         btrfs_set_super_total_bytes(super_copy, old_total + diff);
1907         device->fs_devices->total_rw_bytes += diff;
1908
1909         device->total_bytes = new_size;
1910         device->disk_total_bytes = new_size;
1911         btrfs_clear_space_info_full(device->dev_root->fs_info);
1912
1913         return btrfs_update_device(trans, device);
1914 }
1915
1916 int btrfs_grow_device(struct btrfs_trans_handle *trans,
1917                       struct btrfs_device *device, u64 new_size)
1918 {
1919         int ret;
1920         lock_chunks(device->dev_root);
1921         ret = __btrfs_grow_device(trans, device, new_size);
1922         unlock_chunks(device->dev_root);
1923         return ret;
1924 }
1925
1926 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
1927                             struct btrfs_root *root,
1928                             u64 chunk_tree, u64 chunk_objectid,
1929                             u64 chunk_offset)
1930 {
1931         int ret;
1932         struct btrfs_path *path;
1933         struct btrfs_key key;
1934
1935         root = root->fs_info->chunk_root;
1936         path = btrfs_alloc_path();
1937         if (!path)
1938                 return -ENOMEM;
1939
1940         key.objectid = chunk_objectid;
1941         key.offset = chunk_offset;
1942         key.type = BTRFS_CHUNK_ITEM_KEY;
1943
1944         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1945         if (ret < 0)
1946                 goto out;
1947         else if (ret > 0) { /* Logic error or corruption */
1948                 btrfs_error(root->fs_info, -ENOENT,
1949                             "Failed lookup while freeing chunk.");
1950                 ret = -ENOENT;
1951                 goto out;
1952         }
1953
1954         ret = btrfs_del_item(trans, root, path);
1955         if (ret < 0)
1956                 btrfs_error(root->fs_info, ret,
1957                             "Failed to delete chunk item.");
1958 out:
1959         btrfs_free_path(path);
1960         return ret;
1961 }
1962
1963 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
1964                         chunk_offset)
1965 {
1966         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
1967         struct btrfs_disk_key *disk_key;
1968         struct btrfs_chunk *chunk;
1969         u8 *ptr;
1970         int ret = 0;
1971         u32 num_stripes;
1972         u32 array_size;
1973         u32 len = 0;
1974         u32 cur;
1975         struct btrfs_key key;
1976
1977         array_size = btrfs_super_sys_array_size(super_copy);
1978
1979         ptr = super_copy->sys_chunk_array;
1980         cur = 0;
1981
1982         while (cur < array_size) {
1983                 disk_key = (struct btrfs_disk_key *)ptr;
1984                 btrfs_disk_key_to_cpu(&key, disk_key);
1985
1986                 len = sizeof(*disk_key);
1987
1988                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
1989                         chunk = (struct btrfs_chunk *)(ptr + len);
1990                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
1991                         len += btrfs_chunk_item_size(num_stripes);
1992                 } else {
1993                         ret = -EIO;
1994                         break;
1995                 }
1996                 if (key.objectid == chunk_objectid &&
1997                     key.offset == chunk_offset) {
1998                         memmove(ptr, ptr + len, array_size - (cur + len));
1999                         array_size -= len;
2000                         btrfs_set_super_sys_array_size(super_copy, array_size);
2001                 } else {
2002                         ptr += len;
2003                         cur += len;
2004                 }
2005         }
2006         return ret;
2007 }
2008
2009 static int btrfs_relocate_chunk(struct btrfs_root *root,
2010                          u64 chunk_tree, u64 chunk_objectid,
2011                          u64 chunk_offset)
2012 {
2013         struct extent_map_tree *em_tree;
2014         struct btrfs_root *extent_root;
2015         struct btrfs_trans_handle *trans;
2016         struct extent_map *em;
2017         struct map_lookup *map;
2018         int ret;
2019         int i;
2020
2021         root = root->fs_info->chunk_root;
2022         extent_root = root->fs_info->extent_root;
2023         em_tree = &root->fs_info->mapping_tree.map_tree;
2024
2025         ret = btrfs_can_relocate(extent_root, chunk_offset);
2026         if (ret)
2027                 return -ENOSPC;
2028
2029         /* step one, relocate all the extents inside this chunk */
2030         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
2031         if (ret)
2032                 return ret;
2033
2034         trans = btrfs_start_transaction(root, 0);
2035         BUG_ON(IS_ERR(trans));
2036
2037         lock_chunks(root);
2038
2039         /*
2040          * step two, delete the device extents and the
2041          * chunk tree entries
2042          */
2043         read_lock(&em_tree->lock);
2044         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
2045         read_unlock(&em_tree->lock);
2046
2047         BUG_ON(!em || em->start > chunk_offset ||
2048                em->start + em->len < chunk_offset);
2049         map = (struct map_lookup *)em->bdev;
2050
2051         for (i = 0; i < map->num_stripes; i++) {
2052                 ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
2053                                             map->stripes[i].physical);
2054                 BUG_ON(ret);
2055
2056                 if (map->stripes[i].dev) {
2057                         ret = btrfs_update_device(trans, map->stripes[i].dev);
2058                         BUG_ON(ret);
2059                 }
2060         }
2061         ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
2062                                chunk_offset);
2063
2064         BUG_ON(ret);
2065
2066         trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
2067
2068         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2069                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
2070                 BUG_ON(ret);
2071         }
2072
2073         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
2074         BUG_ON(ret);
2075
2076         write_lock(&em_tree->lock);
2077         remove_extent_mapping(em_tree, em);
2078         write_unlock(&em_tree->lock);
2079
2080         kfree(map);
2081         em->bdev = NULL;
2082
2083         /* once for the tree */
2084         free_extent_map(em);
2085         /* once for us */
2086         free_extent_map(em);
2087
2088         unlock_chunks(root);
2089         btrfs_end_transaction(trans, root);
2090         return 0;
2091 }
2092
2093 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
2094 {
2095         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
2096         struct btrfs_path *path;
2097         struct extent_buffer *leaf;
2098         struct btrfs_chunk *chunk;
2099         struct btrfs_key key;
2100         struct btrfs_key found_key;
2101         u64 chunk_tree = chunk_root->root_key.objectid;
2102         u64 chunk_type;
2103         bool retried = false;
2104         int failed = 0;
2105         int ret;
2106
2107         path = btrfs_alloc_path();
2108         if (!path)
2109                 return -ENOMEM;
2110
2111 again:
2112         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2113         key.offset = (u64)-1;
2114         key.type = BTRFS_CHUNK_ITEM_KEY;
2115
2116         while (1) {
2117                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2118                 if (ret < 0)
2119                         goto error;
2120                 BUG_ON(ret == 0); /* Corruption */
2121
2122                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
2123                                           key.type);
2124                 if (ret < 0)
2125                         goto error;
2126                 if (ret > 0)
2127                         break;
2128
2129                 leaf = path->nodes[0];
2130                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2131
2132                 chunk = btrfs_item_ptr(leaf, path->slots[0],
2133                                        struct btrfs_chunk);
2134                 chunk_type = btrfs_chunk_type(leaf, chunk);
2135                 btrfs_release_path(path);
2136
2137                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
2138                         ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
2139                                                    found_key.objectid,
2140                                                    found_key.offset);
2141                         if (ret == -ENOSPC)
2142                                 failed++;
2143                         else if (ret)
2144                                 BUG();
2145                 }
2146
2147                 if (found_key.offset == 0)
2148                         break;
2149                 key.offset = found_key.offset - 1;
2150         }
2151         ret = 0;
2152         if (failed && !retried) {
2153                 failed = 0;
2154                 retried = true;
2155                 goto again;
2156         } else if (failed && retried) {
2157                 WARN_ON(1);
2158                 ret = -ENOSPC;
2159         }
2160 error:
2161         btrfs_free_path(path);
2162         return ret;
2163 }
2164
2165 static int insert_balance_item(struct btrfs_root *root,
2166                                struct btrfs_balance_control *bctl)
2167 {
2168         struct btrfs_trans_handle *trans;
2169         struct btrfs_balance_item *item;
2170         struct btrfs_disk_balance_args disk_bargs;
2171         struct btrfs_path *path;
2172         struct extent_buffer *leaf;
2173         struct btrfs_key key;
2174         int ret, err;
2175
2176         path = btrfs_alloc_path();
2177         if (!path)
2178                 return -ENOMEM;
2179
2180         trans = btrfs_start_transaction(root, 0);
2181         if (IS_ERR(trans)) {
2182                 btrfs_free_path(path);
2183                 return PTR_ERR(trans);
2184         }
2185
2186         key.objectid = BTRFS_BALANCE_OBJECTID;
2187         key.type = BTRFS_BALANCE_ITEM_KEY;
2188         key.offset = 0;
2189
2190         ret = btrfs_insert_empty_item(trans, root, path, &key,
2191                                       sizeof(*item));
2192         if (ret)
2193                 goto out;
2194
2195         leaf = path->nodes[0];
2196         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
2197
2198         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
2199
2200         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);
2201         btrfs_set_balance_data(leaf, item, &disk_bargs);
2202         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->meta);
2203         btrfs_set_balance_meta(leaf, item, &disk_bargs);
2204         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);
2205         btrfs_set_balance_sys(leaf, item, &disk_bargs);
2206
2207         btrfs_set_balance_flags(leaf, item, bctl->flags);
2208
2209         btrfs_mark_buffer_dirty(leaf);
2210 out:
2211         btrfs_free_path(path);
2212         err = btrfs_commit_transaction(trans, root);
2213         if (err && !ret)
2214                 ret = err;
2215         return ret;
2216 }
2217
2218 static int del_balance_item(struct btrfs_root *root)
2219 {
2220         struct btrfs_trans_handle *trans;
2221         struct btrfs_path *path;
2222         struct btrfs_key key;
2223         int ret, err;
2224
2225         path = btrfs_alloc_path();
2226         if (!path)
2227                 return -ENOMEM;
2228
2229         trans = btrfs_start_transaction(root, 0);
2230         if (IS_ERR(trans)) {
2231                 btrfs_free_path(path);
2232                 return PTR_ERR(trans);
2233         }
2234
2235         key.objectid = BTRFS_BALANCE_OBJECTID;
2236         key.type = BTRFS_BALANCE_ITEM_KEY;
2237         key.offset = 0;
2238
2239         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2240         if (ret < 0)
2241                 goto out;
2242         if (ret > 0) {
2243                 ret = -ENOENT;
2244                 goto out;
2245         }
2246
2247         ret = btrfs_del_item(trans, root, path);
2248 out:
2249         btrfs_free_path(path);
2250         err = btrfs_commit_transaction(trans, root);
2251         if (err && !ret)
2252                 ret = err;
2253         return ret;
2254 }
2255
2256 /*
2257  * This is a heuristic used to reduce the number of chunks balanced on
2258  * resume after balance was interrupted.
2259  */
2260 static void update_balance_args(struct btrfs_balance_control *bctl)
2261 {
2262         /*
2263          * Turn on soft mode for chunk types that were being converted.
2264          */
2265         if (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)
2266                 bctl->data.flags |= BTRFS_BALANCE_ARGS_SOFT;
2267         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)
2268                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_SOFT;
2269         if (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)
2270                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_SOFT;
2271
2272         /*
2273          * Turn on usage filter if is not already used.  The idea is
2274          * that chunks that we have already balanced should be
2275          * reasonably full.  Don't do it for chunks that are being
2276          * converted - that will keep us from relocating unconverted
2277          * (albeit full) chunks.
2278          */
2279         if (!(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2280             !(bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2281                 bctl->data.flags |= BTRFS_BALANCE_ARGS_USAGE;
2282                 bctl->data.usage = 90;
2283         }
2284         if (!(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2285             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2286                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_USAGE;
2287                 bctl->sys.usage = 90;
2288         }
2289         if (!(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2290             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2291                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_USAGE;
2292                 bctl->meta.usage = 90;
2293         }
2294 }
2295
2296 /*
2297  * Should be called with both balance and volume mutexes held to
2298  * serialize other volume operations (add_dev/rm_dev/resize) with
2299  * restriper.  Same goes for unset_balance_control.
2300  */
2301 static void set_balance_control(struct btrfs_balance_control *bctl)
2302 {
2303         struct btrfs_fs_info *fs_info = bctl->fs_info;
2304
2305         BUG_ON(fs_info->balance_ctl);
2306
2307         spin_lock(&fs_info->balance_lock);
2308         fs_info->balance_ctl = bctl;
2309         spin_unlock(&fs_info->balance_lock);
2310 }
2311
2312 static void unset_balance_control(struct btrfs_fs_info *fs_info)
2313 {
2314         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2315
2316         BUG_ON(!fs_info->balance_ctl);
2317
2318         spin_lock(&fs_info->balance_lock);
2319         fs_info->balance_ctl = NULL;
2320         spin_unlock(&fs_info->balance_lock);
2321
2322         kfree(bctl);
2323 }
2324
2325 /*
2326  * Balance filters.  Return 1 if chunk should be filtered out
2327  * (should not be balanced).
2328  */
2329 static int chunk_profiles_filter(u64 chunk_type,
2330                                  struct btrfs_balance_args *bargs)
2331 {
2332         chunk_type = chunk_to_extended(chunk_type) &
2333                                 BTRFS_EXTENDED_PROFILE_MASK;
2334
2335         if (bargs->profiles & chunk_type)
2336                 return 0;
2337
2338         return 1;
2339 }
2340
2341 static int chunk_usage_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
2342                               struct btrfs_balance_args *bargs)
2343 {
2344         struct btrfs_block_group_cache *cache;
2345         u64 chunk_used, user_thresh;
2346         int ret = 1;
2347
2348         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
2349         chunk_used = btrfs_block_group_used(&cache->item);
2350
2351         user_thresh = div_factor_fine(cache->key.offset, bargs->usage);
2352         if (chunk_used < user_thresh)
2353                 ret = 0;
2354
2355         btrfs_put_block_group(cache);
2356         return ret;
2357 }
2358
2359 static int chunk_devid_filter(struct extent_buffer *leaf,
2360                               struct btrfs_chunk *chunk,
2361                               struct btrfs_balance_args *bargs)
2362 {
2363         struct btrfs_stripe *stripe;
2364         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2365         int i;
2366
2367         for (i = 0; i < num_stripes; i++) {
2368                 stripe = btrfs_stripe_nr(chunk, i);
2369                 if (btrfs_stripe_devid(leaf, stripe) == bargs->devid)
2370                         return 0;
2371         }
2372
2373         return 1;
2374 }
2375
2376 /* [pstart, pend) */
2377 static int chunk_drange_filter(struct extent_buffer *leaf,
2378                                struct btrfs_chunk *chunk,
2379                                u64 chunk_offset,
2380                                struct btrfs_balance_args *bargs)
2381 {
2382         struct btrfs_stripe *stripe;
2383         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2384         u64 stripe_offset;
2385         u64 stripe_length;
2386         int factor;
2387         int i;
2388
2389         if (!(bargs->flags & BTRFS_BALANCE_ARGS_DEVID))
2390                 return 0;
2391
2392         if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP |
2393              BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10))
2394                 factor = 2;
2395         else
2396                 factor = 1;
2397         factor = num_stripes / factor;
2398
2399         for (i = 0; i < num_stripes; i++) {
2400                 stripe = btrfs_stripe_nr(chunk, i);
2401                 if (btrfs_stripe_devid(leaf, stripe) != bargs->devid)
2402                         continue;
2403
2404                 stripe_offset = btrfs_stripe_offset(leaf, stripe);
2405                 stripe_length = btrfs_chunk_length(leaf, chunk);
2406                 do_div(stripe_length, factor);
2407
2408                 if (stripe_offset < bargs->pend &&
2409                     stripe_offset + stripe_length > bargs->pstart)
2410                         return 0;
2411         }
2412
2413         return 1;
2414 }
2415
2416 /* [vstart, vend) */
2417 static int chunk_vrange_filter(struct extent_buffer *leaf,
2418                                struct btrfs_chunk *chunk,
2419                                u64 chunk_offset,
2420                                struct btrfs_balance_args *bargs)
2421 {
2422         if (chunk_offset < bargs->vend &&
2423             chunk_offset + btrfs_chunk_length(leaf, chunk) > bargs->vstart)
2424                 /* at least part of the chunk is inside this vrange */
2425                 return 0;
2426
2427         return 1;
2428 }
2429
2430 static int chunk_soft_convert_filter(u64 chunk_type,
2431                                      struct btrfs_balance_args *bargs)
2432 {
2433         if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
2434                 return 0;
2435
2436         chunk_type = chunk_to_extended(chunk_type) &
2437                                 BTRFS_EXTENDED_PROFILE_MASK;
2438
2439         if (bargs->target == chunk_type)
2440                 return 1;
2441
2442         return 0;
2443 }
2444
2445 static int should_balance_chunk(struct btrfs_root *root,
2446                                 struct extent_buffer *leaf,
2447                                 struct btrfs_chunk *chunk, u64 chunk_offset)
2448 {
2449         struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
2450         struct btrfs_balance_args *bargs = NULL;
2451         u64 chunk_type = btrfs_chunk_type(leaf, chunk);
2452
2453         /* type filter */
2454         if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
2455               (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
2456                 return 0;
2457         }
2458
2459         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
2460                 bargs = &bctl->data;
2461         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
2462                 bargs = &bctl->sys;
2463         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
2464                 bargs = &bctl->meta;
2465
2466         /* profiles filter */
2467         if ((bargs->flags & BTRFS_BALANCE_ARGS_PROFILES) &&
2468             chunk_profiles_filter(chunk_type, bargs)) {
2469                 return 0;
2470         }
2471
2472         /* usage filter */
2473         if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
2474             chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
2475                 return 0;
2476         }
2477
2478         /* devid filter */
2479         if ((bargs->flags & BTRFS_BALANCE_ARGS_DEVID) &&
2480             chunk_devid_filter(leaf, chunk, bargs)) {
2481                 return 0;
2482         }
2483
2484         /* drange filter, makes sense only with devid filter */
2485         if ((bargs->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
2486             chunk_drange_filter(leaf, chunk, chunk_offset, bargs)) {
2487                 return 0;
2488         }
2489
2490         /* vrange filter */
2491         if ((bargs->flags & BTRFS_BALANCE_ARGS_VRANGE) &&
2492             chunk_vrange_filter(leaf, chunk, chunk_offset, bargs)) {
2493                 return 0;
2494         }
2495
2496         /* soft profile changing mode */
2497         if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
2498             chunk_soft_convert_filter(chunk_type, bargs)) {
2499                 return 0;
2500         }
2501
2502         return 1;
2503 }
2504
2505 static int __btrfs_balance(struct btrfs_fs_info *fs_info)
2506 {
2507         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2508         struct btrfs_root *chunk_root = fs_info->chunk_root;
2509         struct btrfs_root *dev_root = fs_info->dev_root;
2510         struct list_head *devices;
2511         struct btrfs_device *device;
2512         u64 old_size;
2513         u64 size_to_free;
2514         struct btrfs_chunk *chunk;
2515         struct btrfs_path *path;
2516         struct btrfs_key key;
2517         struct btrfs_key found_key;
2518         struct btrfs_trans_handle *trans;
2519         struct extent_buffer *leaf;
2520         int slot;
2521         int ret;
2522         int enospc_errors = 0;
2523         bool counting = true;
2524
2525         /* step one make some room on all the devices */
2526         devices = &fs_info->fs_devices->devices;
2527         list_for_each_entry(device, devices, dev_list) {
2528                 old_size = device->total_bytes;
2529                 size_to_free = div_factor(old_size, 1);
2530                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
2531                 if (!device->writeable ||
2532                     device->total_bytes - device->bytes_used > size_to_free)
2533                         continue;
2534
2535                 ret = btrfs_shrink_device(device, old_size - size_to_free);
2536                 if (ret == -ENOSPC)
2537                         break;
2538                 BUG_ON(ret);
2539
2540                 trans = btrfs_start_transaction(dev_root, 0);
2541                 BUG_ON(IS_ERR(trans));
2542
2543                 ret = btrfs_grow_device(trans, device, old_size);
2544                 BUG_ON(ret);
2545
2546                 btrfs_end_transaction(trans, dev_root);
2547         }
2548
2549         /* step two, relocate all the chunks */
2550         path = btrfs_alloc_path();
2551         if (!path) {
2552                 ret = -ENOMEM;
2553                 goto error;
2554         }
2555
2556         /* zero out stat counters */
2557         spin_lock(&fs_info->balance_lock);
2558         memset(&bctl->stat, 0, sizeof(bctl->stat));
2559         spin_unlock(&fs_info->balance_lock);
2560 again:
2561         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2562         key.offset = (u64)-1;
2563         key.type = BTRFS_CHUNK_ITEM_KEY;
2564
2565         while (1) {
2566                 if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
2567                     atomic_read(&fs_info->balance_cancel_req)) {
2568                         ret = -ECANCELED;
2569                         goto error;
2570                 }
2571
2572                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2573                 if (ret < 0)
2574                         goto error;
2575
2576                 /*
2577                  * this shouldn't happen, it means the last relocate
2578                  * failed
2579                  */
2580                 if (ret == 0)
2581                         BUG(); /* FIXME break ? */
2582
2583                 ret = btrfs_previous_item(chunk_root, path, 0,
2584                                           BTRFS_CHUNK_ITEM_KEY);
2585                 if (ret) {
2586                         ret = 0;
2587                         break;
2588                 }
2589
2590                 leaf = path->nodes[0];
2591                 slot = path->slots[0];
2592                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2593
2594                 if (found_key.objectid != key.objectid)
2595                         break;
2596
2597                 /* chunk zero is special */
2598                 if (found_key.offset == 0)
2599                         break;
2600
2601                 chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
2602
2603                 if (!counting) {
2604                         spin_lock(&fs_info->balance_lock);
2605                         bctl->stat.considered++;
2606                         spin_unlock(&fs_info->balance_lock);
2607                 }
2608
2609                 ret = should_balance_chunk(chunk_root, leaf, chunk,
2610                                            found_key.offset);
2611                 btrfs_release_path(path);
2612                 if (!ret)
2613                         goto loop;
2614
2615                 if (counting) {
2616                         spin_lock(&fs_info->balance_lock);
2617                         bctl->stat.expected++;
2618                         spin_unlock(&fs_info->balance_lock);
2619                         goto loop;
2620                 }
2621
2622                 ret = btrfs_relocate_chunk(chunk_root,
2623                                            chunk_root->root_key.objectid,
2624                                            found_key.objectid,
2625                                            found_key.offset);
2626                 if (ret && ret != -ENOSPC)
2627                         goto error;
2628                 if (ret == -ENOSPC) {
2629                         enospc_errors++;
2630                 } else {
2631                         spin_lock(&fs_info->balance_lock);
2632                         bctl->stat.completed++;
2633                         spin_unlock(&fs_info->balance_lock);
2634                 }
2635 loop:
2636                 key.offset = found_key.offset - 1;
2637         }
2638
2639         if (counting) {
2640                 btrfs_release_path(path);
2641                 counting = false;
2642                 goto again;
2643         }
2644 error:
2645         btrfs_free_path(path);
2646         if (enospc_errors) {
2647                 printk(KERN_INFO "btrfs: %d enospc errors during balance\n",
2648                        enospc_errors);
2649                 if (!ret)
2650                         ret = -ENOSPC;
2651         }
2652
2653         return ret;
2654 }
2655
2656 /**
2657  * alloc_profile_is_valid - see if a given profile is valid and reduced
2658  * @flags: profile to validate
2659  * @extended: if true @flags is treated as an extended profile
2660  */
2661 static int alloc_profile_is_valid(u64 flags, int extended)
2662 {
2663         u64 mask = (extended ? BTRFS_EXTENDED_PROFILE_MASK :
2664                                BTRFS_BLOCK_GROUP_PROFILE_MASK);
2665
2666         flags &= ~BTRFS_BLOCK_GROUP_TYPE_MASK;
2667
2668         /* 1) check that all other bits are zeroed */
2669         if (flags & ~mask)
2670                 return 0;
2671
2672         /* 2) see if profile is reduced */
2673         if (flags == 0)
2674                 return !extended; /* "0" is valid for usual profiles */
2675
2676         /* true if exactly one bit set */
2677         return (flags & (flags - 1)) == 0;
2678 }
2679
2680 static inline int balance_need_close(struct btrfs_fs_info *fs_info)
2681 {
2682         /* cancel requested || normal exit path */
2683         return atomic_read(&fs_info->balance_cancel_req) ||
2684                 (atomic_read(&fs_info->balance_pause_req) == 0 &&
2685                  atomic_read(&fs_info->balance_cancel_req) == 0);
2686 }
2687
2688 static void __cancel_balance(struct btrfs_fs_info *fs_info)
2689 {
2690         int ret;
2691
2692         unset_balance_control(fs_info);
2693         ret = del_balance_item(fs_info->tree_root);
2694         BUG_ON(ret);
2695 }
2696
2697 void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
2698                                struct btrfs_ioctl_balance_args *bargs);
2699
2700 /*
2701  * Should be called with both balance and volume mutexes held
2702  */
2703 int btrfs_balance(struct btrfs_balance_control *bctl,
2704                   struct btrfs_ioctl_balance_args *bargs)
2705 {
2706         struct btrfs_fs_info *fs_info = bctl->fs_info;
2707         u64 allowed;
2708         int mixed = 0;
2709         int ret;
2710
2711         if (btrfs_fs_closing(fs_info) ||
2712             atomic_read(&fs_info->balance_pause_req) ||
2713             atomic_read(&fs_info->balance_cancel_req)) {
2714                 ret = -EINVAL;
2715                 goto out;
2716         }
2717
2718         allowed = btrfs_super_incompat_flags(fs_info->super_copy);
2719         if (allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
2720                 mixed = 1;
2721
2722         /*
2723          * In case of mixed groups both data and meta should be picked,
2724          * and identical options should be given for both of them.
2725          */
2726         allowed = BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA;
2727         if (mixed && (bctl->flags & allowed)) {
2728                 if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
2729                     !(bctl->flags & BTRFS_BALANCE_METADATA) ||
2730                     memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
2731                         printk(KERN_ERR "btrfs: with mixed groups data and "
2732                                "metadata balance options must be the same\n");
2733                         ret = -EINVAL;
2734                         goto out;
2735                 }
2736         }
2737
2738         allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
2739         if (fs_info->fs_devices->num_devices == 1)
2740                 allowed |= BTRFS_BLOCK_GROUP_DUP;
2741         else if (fs_info->fs_devices->num_devices < 4)
2742                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
2743         else
2744                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
2745                                 BTRFS_BLOCK_GROUP_RAID10);
2746
2747         if ((bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
2748             (!alloc_profile_is_valid(bctl->data.target, 1) ||
2749              (bctl->data.target & ~allowed))) {
2750                 printk(KERN_ERR "btrfs: unable to start balance with target "
2751                        "data profile %llu\n",
2752                        (unsigned long long)bctl->data.target);
2753                 ret = -EINVAL;
2754                 goto out;
2755         }
2756         if ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
2757             (!alloc_profile_is_valid(bctl->meta.target, 1) ||
2758              (bctl->meta.target & ~allowed))) {
2759                 printk(KERN_ERR "btrfs: unable to start balance with target "
2760                        "metadata profile %llu\n",
2761                        (unsigned long long)bctl->meta.target);
2762                 ret = -EINVAL;
2763                 goto out;
2764         }
2765         if ((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
2766             (!alloc_profile_is_valid(bctl->sys.target, 1) ||
2767              (bctl->sys.target & ~allowed))) {
2768                 printk(KERN_ERR "btrfs: unable to start balance with target "
2769                        "system profile %llu\n",
2770                        (unsigned long long)bctl->sys.target);
2771                 ret = -EINVAL;
2772                 goto out;
2773         }
2774
2775         /* allow dup'ed data chunks only in mixed mode */
2776         if (!mixed && (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
2777             (bctl->data.target & BTRFS_BLOCK_GROUP_DUP)) {
2778                 printk(KERN_ERR "btrfs: dup for data is not allowed\n");
2779                 ret = -EINVAL;
2780                 goto out;
2781         }
2782
2783         /* allow to reduce meta or sys integrity only if force set */
2784         allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
2785                         BTRFS_BLOCK_GROUP_RAID10;
2786         if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
2787              (fs_info->avail_system_alloc_bits & allowed) &&
2788              !(bctl->sys.target & allowed)) ||
2789             ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
2790              (fs_info->avail_metadata_alloc_bits & allowed) &&
2791              !(bctl->meta.target & allowed))) {
2792                 if (bctl->flags & BTRFS_BALANCE_FORCE) {
2793                         printk(KERN_INFO "btrfs: force reducing metadata "
2794                                "integrity\n");
2795                 } else {
2796                         printk(KERN_ERR "btrfs: balance will reduce metadata "
2797                                "integrity, use force if you want this\n");
2798                         ret = -EINVAL;
2799                         goto out;
2800                 }
2801         }
2802
2803         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
2804                 int num_tolerated_disk_barrier_failures;
2805                 u64 target = bctl->sys.target;
2806
2807                 num_tolerated_disk_barrier_failures =
2808                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
2809                 if (num_tolerated_disk_barrier_failures > 0 &&
2810                     (target &
2811                      (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
2812                       BTRFS_AVAIL_ALLOC_BIT_SINGLE)))
2813                         num_tolerated_disk_barrier_failures = 0;
2814                 else if (num_tolerated_disk_barrier_failures > 1 &&
2815                          (target &
2816                           (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)))
2817                         num_tolerated_disk_barrier_failures = 1;
2818
2819                 fs_info->num_tolerated_disk_barrier_failures =
2820                         num_tolerated_disk_barrier_failures;
2821         }
2822
2823         ret = insert_balance_item(fs_info->tree_root, bctl);
2824         if (ret && ret != -EEXIST)
2825                 goto out;
2826
2827         if (!(bctl->flags & BTRFS_BALANCE_RESUME)) {
2828                 BUG_ON(ret == -EEXIST);
2829                 set_balance_control(bctl);
2830         } else {
2831                 BUG_ON(ret != -EEXIST);
2832                 spin_lock(&fs_info->balance_lock);
2833                 update_balance_args(bctl);
2834                 spin_unlock(&fs_info->balance_lock);
2835         }
2836
2837         atomic_inc(&fs_info->balance_running);
2838         mutex_unlock(&fs_info->balance_mutex);
2839
2840         ret = __btrfs_balance(fs_info);
2841
2842         mutex_lock(&fs_info->balance_mutex);
2843         atomic_dec(&fs_info->balance_running);
2844
2845         if (bargs) {
2846                 memset(bargs, 0, sizeof(*bargs));
2847                 update_ioctl_balance_args(fs_info, 0, bargs);
2848         }
2849
2850         if ((ret && ret != -ECANCELED && ret != -ENOSPC) ||
2851             balance_need_close(fs_info)) {
2852                 __cancel_balance(fs_info);
2853         }
2854
2855         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
2856                 fs_info->num_tolerated_disk_barrier_failures =
2857                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
2858         }
2859
2860         wake_up(&fs_info->balance_wait_q);
2861
2862         return ret;
2863 out:
2864         if (bctl->flags & BTRFS_BALANCE_RESUME)
2865                 __cancel_balance(fs_info);
2866         else
2867                 kfree(bctl);
2868         return ret;
2869 }
2870
2871 static int balance_kthread(void *data)
2872 {
2873         struct btrfs_fs_info *fs_info = data;
2874         int ret = 0;
2875
2876         mutex_lock(&fs_info->volume_mutex);
2877         mutex_lock(&fs_info->balance_mutex);
2878
2879         if (fs_info->balance_ctl) {
2880                 printk(KERN_INFO "btrfs: continuing balance\n");
2881                 ret = btrfs_balance(fs_info->balance_ctl, NULL);
2882         }
2883
2884         mutex_unlock(&fs_info->balance_mutex);
2885         mutex_unlock(&fs_info->volume_mutex);
2886
2887         return ret;
2888 }
2889
2890 int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
2891 {
2892         struct task_struct *tsk;
2893
2894         spin_lock(&fs_info->balance_lock);
2895         if (!fs_info->balance_ctl) {
2896                 spin_unlock(&fs_info->balance_lock);
2897                 return 0;
2898         }
2899         spin_unlock(&fs_info->balance_lock);
2900
2901         if (btrfs_test_opt(fs_info->tree_root, SKIP_BALANCE)) {
2902                 printk(KERN_INFO "btrfs: force skipping balance\n");
2903                 return 0;
2904         }
2905
2906         tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");
2907         if (IS_ERR(tsk))
2908                 return PTR_ERR(tsk);
2909
2910         return 0;
2911 }
2912
2913 int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
2914 {
2915         struct btrfs_balance_control *bctl;
2916         struct btrfs_balance_item *item;
2917         struct btrfs_disk_balance_args disk_bargs;
2918         struct btrfs_path *path;
2919         struct extent_buffer *leaf;
2920         struct btrfs_key key;
2921         int ret;
2922
2923         path = btrfs_alloc_path();
2924         if (!path)
2925                 return -ENOMEM;
2926
2927         key.objectid = BTRFS_BALANCE_OBJECTID;
2928         key.type = BTRFS_BALANCE_ITEM_KEY;
2929         key.offset = 0;
2930
2931         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
2932         if (ret < 0)
2933                 goto out;
2934         if (ret > 0) { /* ret = -ENOENT; */
2935                 ret = 0;
2936                 goto out;
2937         }
2938
2939         bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
2940         if (!bctl) {
2941                 ret = -ENOMEM;
2942                 goto out;
2943         }
2944
2945         leaf = path->nodes[0];
2946         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
2947
2948         bctl->fs_info = fs_info;
2949         bctl->flags = btrfs_balance_flags(leaf, item);
2950         bctl->flags |= BTRFS_BALANCE_RESUME;
2951
2952         btrfs_balance_data(leaf, item, &disk_bargs);
2953         btrfs_disk_balance_args_to_cpu(&bctl->data, &disk_bargs);
2954         btrfs_balance_meta(leaf, item, &disk_bargs);
2955         btrfs_disk_balance_args_to_cpu(&bctl->meta, &disk_bargs);
2956         btrfs_balance_sys(leaf, item, &disk_bargs);
2957         btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
2958
2959         mutex_lock(&fs_info->volume_mutex);
2960         mutex_lock(&fs_info->balance_mutex);
2961
2962         set_balance_control(bctl);
2963
2964         mutex_unlock(&fs_info->balance_mutex);
2965         mutex_unlock(&fs_info->volume_mutex);
2966 out:
2967         btrfs_free_path(path);
2968         return ret;
2969 }
2970
2971 int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
2972 {
2973         int ret = 0;
2974
2975         mutex_lock(&fs_info->balance_mutex);
2976         if (!fs_info->balance_ctl) {
2977                 mutex_unlock(&fs_info->balance_mutex);
2978                 return -ENOTCONN;
2979         }
2980
2981         if (atomic_read(&fs_info->balance_running)) {
2982                 atomic_inc(&fs_info->balance_pause_req);
2983                 mutex_unlock(&fs_info->balance_mutex);
2984
2985                 wait_event(fs_info->balance_wait_q,
2986                            atomic_read(&fs_info->balance_running) == 0);
2987
2988                 mutex_lock(&fs_info->balance_mutex);
2989                 /* we are good with balance_ctl ripped off from under us */
2990                 BUG_ON(atomic_read(&fs_info->balance_running));
2991                 atomic_dec(&fs_info->balance_pause_req);
2992         } else {
2993                 ret = -ENOTCONN;
2994         }
2995
2996         mutex_unlock(&fs_info->balance_mutex);
2997         return ret;
2998 }
2999
3000 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
3001 {
3002         mutex_lock(&fs_info->balance_mutex);
3003         if (!fs_info->balance_ctl) {
3004                 mutex_unlock(&fs_info->balance_mutex);
3005                 return -ENOTCONN;
3006         }
3007
3008         atomic_inc(&fs_info->balance_cancel_req);
3009         /*
3010          * if we are running just wait and return, balance item is
3011          * deleted in btrfs_balance in this case
3012          */
3013         if (atomic_read(&fs_info->balance_running)) {
3014                 mutex_unlock(&fs_info->balance_mutex);
3015                 wait_event(fs_info->balance_wait_q,
3016                            atomic_read(&fs_info->balance_running) == 0);
3017                 mutex_lock(&fs_info->balance_mutex);
3018         } else {
3019                 /* __cancel_balance needs volume_mutex */
3020                 mutex_unlock(&fs_info->balance_mutex);
3021                 mutex_lock(&fs_info->volume_mutex);
3022                 mutex_lock(&fs_info->balance_mutex);
3023
3024                 if (fs_info->balance_ctl)
3025                         __cancel_balance(fs_info);
3026
3027                 mutex_unlock(&fs_info->volume_mutex);
3028         }
3029
3030         BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
3031         atomic_dec(&fs_info->balance_cancel_req);
3032         mutex_unlock(&fs_info->balance_mutex);
3033         return 0;
3034 }
3035
3036 /*
3037  * shrinking a device means finding all of the device extents past
3038  * the new size, and then following the back refs to the chunks.
3039  * The chunk relocation code actually frees the device extent
3040  */
3041 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
3042 {
3043         struct btrfs_trans_handle *trans;
3044         struct btrfs_root *root = device->dev_root;
3045         struct btrfs_dev_extent *dev_extent = NULL;
3046         struct btrfs_path *path;
3047         u64 length;
3048         u64 chunk_tree;
3049         u64 chunk_objectid;
3050         u64 chunk_offset;
3051         int ret;
3052         int slot;
3053         int failed = 0;
3054         bool retried = false;
3055         struct extent_buffer *l;
3056         struct btrfs_key key;
3057         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3058         u64 old_total = btrfs_super_total_bytes(super_copy);
3059         u64 old_size = device->total_bytes;
3060         u64 diff = device->total_bytes - new_size;
3061
3062         if (new_size >= device->total_bytes)
3063                 return -EINVAL;
3064
3065         path = btrfs_alloc_path();
3066         if (!path)
3067                 return -ENOMEM;
3068
3069         path->reada = 2;
3070
3071         lock_chunks(root);
3072
3073         device->total_bytes = new_size;
3074         if (device->writeable) {
3075                 device->fs_devices->total_rw_bytes -= diff;
3076                 spin_lock(&root->fs_info->free_chunk_lock);
3077                 root->fs_info->free_chunk_space -= diff;
3078                 spin_unlock(&root->fs_info->free_chunk_lock);
3079         }
3080         unlock_chunks(root);
3081
3082 again:
3083         key.objectid = device->devid;
3084         key.offset = (u64)-1;
3085         key.type = BTRFS_DEV_EXTENT_KEY;
3086
3087         do {
3088                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3089                 if (ret < 0)
3090                         goto done;
3091
3092                 ret = btrfs_previous_item(root, path, 0, key.type);
3093                 if (ret < 0)
3094                         goto done;
3095                 if (ret) {
3096                         ret = 0;
3097                         btrfs_release_path(path);
3098                         break;
3099                 }
3100
3101                 l = path->nodes[0];
3102                 slot = path->slots[0];
3103                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
3104
3105                 if (key.objectid != device->devid) {
3106                         btrfs_release_path(path);
3107                         break;
3108                 }
3109
3110                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
3111                 length = btrfs_dev_extent_length(l, dev_extent);
3112
3113                 if (key.offset + length <= new_size) {
3114                         btrfs_release_path(path);
3115                         break;
3116                 }
3117
3118                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
3119                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
3120                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
3121                 btrfs_release_path(path);
3122
3123                 ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
3124                                            chunk_offset);
3125                 if (ret && ret != -ENOSPC)
3126                         goto done;
3127                 if (ret == -ENOSPC)
3128                         failed++;
3129         } while (key.offset-- > 0);
3130
3131         if (failed && !retried) {
3132                 failed = 0;
3133                 retried = true;
3134                 goto again;
3135         } else if (failed && retried) {
3136                 ret = -ENOSPC;
3137                 lock_chunks(root);
3138
3139                 device->total_bytes = old_size;
3140                 if (device->writeable)
3141                         device->fs_devices->total_rw_bytes += diff;
3142                 spin_lock(&root->fs_info->free_chunk_lock);
3143                 root->fs_info->free_chunk_space += diff;
3144                 spin_unlock(&root->fs_info->free_chunk_lock);
3145                 unlock_chunks(root);
3146                 goto done;
3147         }
3148
3149         /* Shrinking succeeded, else we would be at "done". */
3150         trans = btrfs_start_transaction(root, 0);
3151         if (IS_ERR(trans)) {
3152                 ret = PTR_ERR(trans);
3153                 goto done;
3154         }
3155
3156         lock_chunks(root);
3157
3158         device->disk_total_bytes = new_size;
3159         /* Now btrfs_update_device() will change the on-disk size. */
3160         ret = btrfs_update_device(trans, device);
3161         if (ret) {
3162                 unlock_chunks(root);
3163                 btrfs_end_transaction(trans, root);
3164                 goto done;
3165         }
3166         WARN_ON(diff > old_total);
3167         btrfs_set_super_total_bytes(super_copy, old_total - diff);
3168         unlock_chunks(root);
3169         btrfs_end_transaction(trans, root);
3170 done:
3171         btrfs_free_path(path);
3172         return ret;
3173 }
3174
3175 static int btrfs_add_system_chunk(struct btrfs_root *root,
3176                            struct btrfs_key *key,
3177                            struct btrfs_chunk *chunk, int item_size)
3178 {
3179         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3180         struct btrfs_disk_key disk_key;
3181         u32 array_size;
3182         u8 *ptr;
3183
3184         array_size = btrfs_super_sys_array_size(super_copy);
3185         if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
3186                 return -EFBIG;
3187
3188         ptr = super_copy->sys_chunk_array + array_size;
3189         btrfs_cpu_key_to_disk(&disk_key, key);
3190         memcpy(ptr, &disk_key, sizeof(disk_key));
3191         ptr += sizeof(disk_key);
3192         memcpy(ptr, chunk, item_size);
3193         item_size += sizeof(disk_key);
3194         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
3195         return 0;
3196 }
3197
3198 /*
3199  * sort the devices in descending order by max_avail, total_avail
3200  */
3201 static int btrfs_cmp_device_info(const void *a, const void *b)
3202 {
3203         const struct btrfs_device_info *di_a = a;
3204         const struct btrfs_device_info *di_b = b;
3205
3206         if (di_a->max_avail > di_b->max_avail)
3207                 return -1;
3208         if (di_a->max_avail < di_b->max_avail)
3209                 return 1;
3210         if (di_a->total_avail > di_b->total_avail)
3211                 return -1;
3212         if (di_a->total_avail < di_b->total_avail)
3213                 return 1;
3214         return 0;
3215 }
3216
3217 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
3218                                struct btrfs_root *extent_root,
3219                                struct map_lookup **map_ret,
3220                                u64 *num_bytes_out, u64 *stripe_size_out,
3221                                u64 start, u64 type)
3222 {
3223         struct btrfs_fs_info *info = extent_root->fs_info;
3224         struct btrfs_fs_devices *fs_devices = info->fs_devices;
3225         struct list_head *cur;
3226         struct map_lookup *map = NULL;
3227         struct extent_map_tree *em_tree;
3228         struct extent_map *em;
3229         struct btrfs_device_info *devices_info = NULL;
3230         u64 total_avail;
3231         int num_stripes;        /* total number of stripes to allocate */
3232         int sub_stripes;        /* sub_stripes info for map */
3233         int dev_stripes;        /* stripes per dev */
3234         int devs_max;           /* max devs to use */
3235         int devs_min;           /* min devs needed */
3236         int devs_increment;     /* ndevs has to be a multiple of this */
3237         int ncopies;            /* how many copies to data has */
3238         int ret;
3239         u64 max_stripe_size;
3240         u64 max_chunk_size;
3241         u64 stripe_size;
3242         u64 num_bytes;
3243         int ndevs;
3244         int i;
3245         int j;
3246
3247         BUG_ON(!alloc_profile_is_valid(type, 0));
3248
3249         if (list_empty(&fs_devices->alloc_list))
3250                 return -ENOSPC;
3251
3252         sub_stripes = 1;
3253         dev_stripes = 1;
3254         devs_increment = 1;
3255         ncopies = 1;
3256         devs_max = 0;   /* 0 == as many as possible */
3257         devs_min = 1;
3258
3259         /*
3260          * define the properties of each RAID type.
3261          * FIXME: move this to a global table and use it in all RAID
3262          * calculation code
3263          */
3264         if (type & (BTRFS_BLOCK_GROUP_DUP)) {
3265                 dev_stripes = 2;
3266                 ncopies = 2;
3267                 devs_max = 1;
3268         } else if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
3269                 devs_min = 2;
3270         } else if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
3271                 devs_increment = 2;
3272                 ncopies = 2;
3273                 devs_max = 2;
3274                 devs_min = 2;
3275         } else if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
3276                 sub_stripes = 2;
3277                 devs_increment = 2;
3278                 ncopies = 2;
3279                 devs_min = 4;
3280         } else {
3281                 devs_max = 1;
3282         }
3283
3284         if (type & BTRFS_BLOCK_GROUP_DATA) {
3285                 max_stripe_size = 1024 * 1024 * 1024;
3286                 max_chunk_size = 10 * max_stripe_size;
3287         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
3288                 /* for larger filesystems, use larger metadata chunks */
3289                 if (fs_devices->total_rw_bytes > 50ULL * 1024 * 1024 * 1024)
3290                         max_stripe_size = 1024 * 1024 * 1024;
3291                 else
3292                         max_stripe_size = 256 * 1024 * 1024;
3293                 max_chunk_size = max_stripe_size;
3294         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
3295                 max_stripe_size = 32 * 1024 * 1024;
3296                 max_chunk_size = 2 * max_stripe_size;
3297         } else {
3298                 printk(KERN_ERR "btrfs: invalid chunk type 0x%llx requested\n",
3299                        type);
3300                 BUG_ON(1);
3301         }
3302
3303         /* we don't want a chunk larger than 10% of writeable space */
3304         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
3305                              max_chunk_size);
3306
3307         devices_info = kzalloc(sizeof(*devices_info) * fs_devices->rw_devices,
3308                                GFP_NOFS);
3309         if (!devices_info)
3310                 return -ENOMEM;
3311
3312         cur = fs_devices->alloc_list.next;
3313
3314         /*
3315          * in the first pass through the devices list, we gather information
3316          * about the available holes on each device.
3317          */
3318         ndevs = 0;
3319         while (cur != &fs_devices->alloc_list) {
3320                 struct btrfs_device *device;
3321                 u64 max_avail;
3322                 u64 dev_offset;
3323
3324                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
3325
3326                 cur = cur->next;
3327
3328                 if (!device->writeable) {
3329                         printk(KERN_ERR
3330                                "btrfs: read-only device in alloc_list\n");
3331                         WARN_ON(1);
3332                         continue;
3333                 }
3334
3335                 if (!device->in_fs_metadata)
3336                         continue;
3337
3338                 if (device->total_bytes > device->bytes_used)
3339                         total_avail = device->total_bytes - device->bytes_used;
3340                 else
3341                         total_avail = 0;
3342
3343                 /* If there is no space on this device, skip it. */
3344                 if (total_avail == 0)
3345                         continue;
3346
3347                 ret = find_free_dev_extent(device,
3348                                            max_stripe_size * dev_stripes,
3349                                            &dev_offset, &max_avail);
3350                 if (ret && ret != -ENOSPC)
3351                         goto error;
3352
3353                 if (ret == 0)
3354                         max_avail = max_stripe_size * dev_stripes;
3355
3356                 if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
3357                         continue;
3358
3359                 devices_info[ndevs].dev_offset = dev_offset;
3360                 devices_info[ndevs].max_avail = max_avail;
3361                 devices_info[ndevs].total_avail = total_avail;
3362                 devices_info[ndevs].dev = device;
3363                 ++ndevs;
3364         }
3365
3366         /*
3367          * now sort the devices by hole size / available space
3368          */
3369         sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
3370              btrfs_cmp_device_info, NULL);
3371
3372         /* round down to number of usable stripes */
3373         ndevs -= ndevs % devs_increment;
3374
3375         if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
3376                 ret = -ENOSPC;
3377                 goto error;
3378         }
3379
3380         if (devs_max && ndevs > devs_max)
3381                 ndevs = devs_max;
3382         /*
3383          * the primary goal is to maximize the number of stripes, so use as many
3384          * devices as possible, even if the stripes are not maximum sized.
3385          */
3386         stripe_size = devices_info[ndevs-1].max_avail;
3387         num_stripes = ndevs * dev_stripes;
3388
3389         if (stripe_size * ndevs > max_chunk_size * ncopies) {
3390                 stripe_size = max_chunk_size * ncopies;
3391                 do_div(stripe_size, ndevs);
3392         }
3393
3394         do_div(stripe_size, dev_stripes);
3395
3396         /* align to BTRFS_STRIPE_LEN */
3397         do_div(stripe_size, BTRFS_STRIPE_LEN);
3398         stripe_size *= BTRFS_STRIPE_LEN;
3399
3400         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
3401         if (!map) {
3402                 ret = -ENOMEM;
3403                 goto error;
3404         }
3405         map->num_stripes = num_stripes;
3406
3407         for (i = 0; i < ndevs; ++i) {
3408                 for (j = 0; j < dev_stripes; ++j) {
3409                         int s = i * dev_stripes + j;
3410                         map->stripes[s].dev = devices_info[i].dev;
3411                         map->stripes[s].physical = devices_info[i].dev_offset +
3412                                                    j * stripe_size;
3413                 }
3414         }
3415         map->sector_size = extent_root->sectorsize;
3416         map->stripe_len = BTRFS_STRIPE_LEN;
3417         map->io_align = BTRFS_STRIPE_LEN;
3418         map->io_width = BTRFS_STRIPE_LEN;
3419         map->type = type;
3420         map->sub_stripes = sub_stripes;
3421
3422         *map_ret = map;
3423         num_bytes = stripe_size * (num_stripes / ncopies);
3424
3425         *stripe_size_out = stripe_size;
3426         *num_bytes_out = num_bytes;
3427
3428         trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
3429
3430         em = alloc_extent_map();
3431         if (!em) {
3432                 ret = -ENOMEM;
3433                 goto error;
3434         }
3435         em->bdev = (struct block_device *)map;
3436         em->start = start;
3437         em->len = num_bytes;
3438         em->block_start = 0;
3439         em->block_len = em->len;
3440
3441         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
3442         write_lock(&em_tree->lock);
3443         ret = add_extent_mapping(em_tree, em);
3444         write_unlock(&em_tree->lock);
3445         free_extent_map(em);
3446         if (ret)
3447                 goto error;
3448
3449         ret = btrfs_make_block_group(trans, extent_root, 0, type,
3450                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3451                                      start, num_bytes);
3452         if (ret)
3453                 goto error;
3454
3455         for (i = 0; i < map->num_stripes; ++i) {
3456                 struct btrfs_device *device;
3457                 u64 dev_offset;
3458
3459                 device = map->stripes[i].dev;
3460                 dev_offset = map->stripes[i].physical;
3461
3462                 ret = btrfs_alloc_dev_extent(trans, device,
3463                                 info->chunk_root->root_key.objectid,
3464                                 BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3465                                 start, dev_offset, stripe_size);
3466                 if (ret) {
3467                         btrfs_abort_transaction(trans, extent_root, ret);
3468                         goto error;
3469                 }
3470         }
3471
3472         kfree(devices_info);
3473         return 0;
3474
3475 error:
3476         kfree(map);
3477         kfree(devices_info);
3478         return ret;
3479 }
3480
3481 static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
3482                                 struct btrfs_root *extent_root,
3483                                 struct map_lookup *map, u64 chunk_offset,
3484                                 u64 chunk_size, u64 stripe_size)
3485 {
3486         u64 dev_offset;
3487         struct btrfs_key key;
3488         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
3489         struct btrfs_device *device;
3490         struct btrfs_chunk *chunk;
3491         struct btrfs_stripe *stripe;
3492         size_t item_size = btrfs_chunk_item_size(map->num_stripes);
3493         int index = 0;
3494         int ret;
3495
3496         chunk = kzalloc(item_size, GFP_NOFS);
3497         if (!chunk)
3498                 return -ENOMEM;
3499
3500         index = 0;
3501         while (index < map->num_stripes) {
3502                 device = map->stripes[index].dev;
3503                 device->bytes_used += stripe_size;
3504                 ret = btrfs_update_device(trans, device);
3505                 if (ret)
3506                         goto out_free;
3507                 index++;
3508         }
3509
3510         spin_lock(&extent_root->fs_info->free_chunk_lock);
3511         extent_root->fs_info->free_chunk_space -= (stripe_size *
3512                                                    map->num_stripes);
3513         spin_unlock(&extent_root->fs_info->free_chunk_lock);
3514
3515         index = 0;
3516         stripe = &chunk->stripe;
3517         while (index < map->num_stripes) {
3518                 device = map->stripes[index].dev;
3519                 dev_offset = map->stripes[index].physical;
3520
3521                 btrfs_set_stack_stripe_devid(stripe, device->devid);
3522                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
3523                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
3524                 stripe++;
3525                 index++;
3526         }
3527
3528         btrfs_set_stack_chunk_length(chunk, chunk_size);
3529         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
3530         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
3531         btrfs_set_stack_chunk_type(chunk, map->type);
3532         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
3533         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
3534         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
3535         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
3536         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
3537
3538         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
3539         key.type = BTRFS_CHUNK_ITEM_KEY;
3540         key.offset = chunk_offset;
3541
3542         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
3543
3544         if (ret == 0 && map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
3545                 /*
3546                  * TODO: Cleanup of inserted chunk root in case of
3547                  * failure.
3548                  */
3549                 ret = btrfs_add_system_chunk(chunk_root, &key, chunk,
3550                                              item_size);
3551         }
3552
3553 out_free:
3554         kfree(chunk);
3555         return ret;
3556 }
3557
3558 /*
3559  * Chunk allocation falls into two parts. The first part does works
3560  * that make the new allocated chunk useable, but not do any operation
3561  * that modifies the chunk tree. The second part does the works that
3562  * require modifying the chunk tree. This division is important for the
3563  * bootstrap process of adding storage to a seed btrfs.
3564  */
3565 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
3566                       struct btrfs_root *extent_root, u64 type)
3567 {
3568         u64 chunk_offset;
3569         u64 chunk_size;
3570         u64 stripe_size;
3571         struct map_lookup *map;
3572         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
3573         int ret;
3574
3575         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3576                               &chunk_offset);
3577         if (ret)
3578                 return ret;
3579
3580         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
3581                                   &stripe_size, chunk_offset, type);
3582         if (ret)
3583                 return ret;
3584
3585         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
3586                                    chunk_size, stripe_size);
3587         if (ret)
3588                 return ret;
3589         return 0;
3590 }
3591
3592 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
3593                                          struct btrfs_root *root,
3594                                          struct btrfs_device *device)
3595 {
3596         u64 chunk_offset;
3597         u64 sys_chunk_offset;
3598         u64 chunk_size;
3599         u64 sys_chunk_size;
3600         u64 stripe_size;
3601         u64 sys_stripe_size;
3602         u64 alloc_profile;
3603         struct map_lookup *map;
3604         struct map_lookup *sys_map;
3605         struct btrfs_fs_info *fs_info = root->fs_info;
3606         struct btrfs_root *extent_root = fs_info->extent_root;
3607         int ret;
3608
3609         ret = find_next_chunk(fs_info->chunk_root,
3610                               BTRFS_FIRST_CHUNK_TREE_OBJECTID, &chunk_offset);
3611         if (ret)
3612                 return ret;
3613
3614         alloc_profile = BTRFS_BLOCK_GROUP_METADATA |
3615                                 fs_info->avail_metadata_alloc_bits;
3616         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
3617
3618         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
3619                                   &stripe_size, chunk_offset, alloc_profile);
3620         if (ret)
3621                 return ret;
3622
3623         sys_chunk_offset = chunk_offset + chunk_size;
3624
3625         alloc_profile = BTRFS_BLOCK_GROUP_SYSTEM |
3626                                 fs_info->avail_system_alloc_bits;
3627         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
3628
3629         ret = __btrfs_alloc_chunk(trans, extent_root, &sys_map,
3630                                   &sys_chunk_size, &sys_stripe_size,
3631                                   sys_chunk_offset, alloc_profile);
3632         if (ret) {
3633                 btrfs_abort_transaction(trans, root, ret);
3634                 goto out;
3635         }
3636
3637         ret = btrfs_add_device(trans, fs_info->chunk_root, device);
3638         if (ret) {
3639                 btrfs_abort_transaction(trans, root, ret);
3640                 goto out;
3641         }
3642
3643         /*
3644          * Modifying chunk tree needs allocating new blocks from both
3645          * system block group and metadata block group. So we only can
3646          * do operations require modifying the chunk tree after both
3647          * block groups were created.
3648          */
3649         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
3650                                    chunk_size, stripe_size);
3651         if (ret) {
3652                 btrfs_abort_transaction(trans, root, ret);
3653                 goto out;
3654         }
3655
3656         ret = __finish_chunk_alloc(trans, extent_root, sys_map,
3657                                    sys_chunk_offset, sys_chunk_size,
3658                                    sys_stripe_size);
3659         if (ret)
3660                 btrfs_abort_transaction(trans, root, ret);
3661
3662 out:
3663
3664         return ret;
3665 }
3666
3667 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
3668 {
3669         struct extent_map *em;
3670         struct map_lookup *map;
3671         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
3672         int readonly = 0;
3673         int i;
3674
3675         read_lock(&map_tree->map_tree.lock);
3676         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
3677         read_unlock(&map_tree->map_tree.lock);
3678         if (!em)
3679                 return 1;
3680
3681         if (btrfs_test_opt(root, DEGRADED)) {
3682                 free_extent_map(em);
3683                 return 0;
3684         }
3685
3686         map = (struct map_lookup *)em->bdev;
3687         for (i = 0; i < map->num_stripes; i++) {
3688                 if (!map->stripes[i].dev->writeable) {
3689                         readonly = 1;
3690                         break;
3691                 }
3692         }
3693         free_extent_map(em);
3694         return readonly;
3695 }
3696
3697 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
3698 {
3699         extent_map_tree_init(&tree->map_tree);
3700 }
3701
3702 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
3703 {
3704         struct extent_map *em;
3705
3706         while (1) {
3707                 write_lock(&tree->map_tree.lock);
3708                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
3709                 if (em)
3710                         remove_extent_mapping(&tree->map_tree, em);
3711                 write_unlock(&tree->map_tree.lock);
3712                 if (!em)
3713                         break;
3714                 kfree(em->bdev);
3715                 /* once for us */
3716                 free_extent_map(em);
3717                 /* once for the tree */
3718                 free_extent_map(em);
3719         }
3720 }
3721
3722 int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
3723 {
3724         struct extent_map *em;
3725         struct map_lookup *map;
3726         struct extent_map_tree *em_tree = &map_tree->map_tree;
3727         int ret;
3728
3729         read_lock(&em_tree->lock);
3730         em = lookup_extent_mapping(em_tree, logical, len);
3731         read_unlock(&em_tree->lock);
3732         BUG_ON(!em);
3733
3734         BUG_ON(em->start > logical || em->start + em->len < logical);
3735         map = (struct map_lookup *)em->bdev;
3736         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
3737                 ret = map->num_stripes;
3738         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
3739                 ret = map->sub_stripes;
3740         else
3741                 ret = 1;
3742         free_extent_map(em);
3743         return ret;
3744 }
3745
3746 static int find_live_mirror(struct map_lookup *map, int first, int num,
3747                             int optimal)
3748 {
3749         int i;
3750         if (map->stripes[optimal].dev->bdev)
3751                 return optimal;
3752         for (i = first; i < first + num; i++) {
3753                 if (map->stripes[i].dev->bdev)
3754                         return i;
3755         }
3756         /* we couldn't find one that doesn't fail.  Just return something
3757          * and the io error handling code will clean up eventually
3758          */
3759         return optimal;
3760 }
3761
3762 static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
3763                              u64 logical, u64 *length,
3764                              struct btrfs_bio **bbio_ret,
3765                              int mirror_num)
3766 {
3767         struct extent_map *em;
3768         struct map_lookup *map;
3769         struct extent_map_tree *em_tree = &map_tree->map_tree;
3770         u64 offset;
3771         u64 stripe_offset;
3772         u64 stripe_end_offset;
3773         u64 stripe_nr;
3774         u64 stripe_nr_orig;
3775         u64 stripe_nr_end;
3776         int stripe_index;
3777         int i;
3778         int ret = 0;
3779         int num_stripes;
3780         int max_errors = 0;
3781         struct btrfs_bio *bbio = NULL;
3782
3783         read_lock(&em_tree->lock);
3784         em = lookup_extent_mapping(em_tree, logical, *length);
3785         read_unlock(&em_tree->lock);
3786
3787         if (!em) {
3788                 printk(KERN_CRIT "btrfs: unable to find logical %llu len %llu\n",
3789                        (unsigned long long)logical,
3790                        (unsigned long long)*length);
3791                 BUG();
3792         }
3793
3794         BUG_ON(em->start > logical || em->start + em->len < logical);
3795         map = (struct map_lookup *)em->bdev;
3796         offset = logical - em->start;
3797
3798         if (mirror_num > map->num_stripes)
3799                 mirror_num = 0;
3800
3801         stripe_nr = offset;
3802         /*
3803          * stripe_nr counts the total number of stripes we have to stride
3804          * to get to this block
3805          */
3806         do_div(stripe_nr, map->stripe_len);
3807
3808         stripe_offset = stripe_nr * map->stripe_len;
3809         BUG_ON(offset < stripe_offset);
3810
3811         /* stripe_offset is the offset of this block in its stripe*/
3812         stripe_offset = offset - stripe_offset;
3813
3814         if (rw & REQ_DISCARD)
3815                 *length = min_t(u64, em->len - offset, *length);
3816         else if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
3817                 /* we limit the length of each bio to what fits in a stripe */
3818                 *length = min_t(u64, em->len - offset,
3819                                 map->stripe_len - stripe_offset);
3820         } else {
3821                 *length = em->len - offset;
3822         }
3823
3824         if (!bbio_ret)
3825                 goto out;
3826
3827         num_stripes = 1;
3828         stripe_index = 0;
3829         stripe_nr_orig = stripe_nr;
3830         stripe_nr_end = (offset + *length + map->stripe_len - 1) &
3831                         (~(map->stripe_len - 1));
3832         do_div(stripe_nr_end, map->stripe_len);
3833         stripe_end_offset = stripe_nr_end * map->stripe_len -
3834                             (offset + *length);
3835         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
3836                 if (rw & REQ_DISCARD)
3837                         num_stripes = min_t(u64, map->num_stripes,
3838                                             stripe_nr_end - stripe_nr_orig);
3839                 stripe_index = do_div(stripe_nr, map->num_stripes);
3840         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
3841                 if (rw & (REQ_WRITE | REQ_DISCARD))
3842                         num_stripes = map->num_stripes;
3843                 else if (mirror_num)
3844                         stripe_index = mirror_num - 1;
3845                 else {
3846                         stripe_index = find_live_mirror(map, 0,
3847                                             map->num_stripes,
3848                                             current->pid % map->num_stripes);
3849                         mirror_num = stripe_index + 1;
3850                 }
3851
3852         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
3853                 if (rw & (REQ_WRITE | REQ_DISCARD)) {
3854                         num_stripes = map->num_stripes;
3855                 } else if (mirror_num) {
3856                         stripe_index = mirror_num - 1;
3857                 } else {
3858                         mirror_num = 1;
3859                 }
3860
3861         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
3862                 int factor = map->num_stripes / map->sub_stripes;
3863
3864                 stripe_index = do_div(stripe_nr, factor);
3865                 stripe_index *= map->sub_stripes;
3866
3867                 if (rw & REQ_WRITE)
3868                         num_stripes = map->sub_stripes;
3869                 else if (rw & REQ_DISCARD)
3870                         num_stripes = min_t(u64, map->sub_stripes *
3871                                             (stripe_nr_end - stripe_nr_orig),
3872                                             map->num_stripes);
3873                 else if (mirror_num)
3874                         stripe_index += mirror_num - 1;
3875                 else {
3876                         int old_stripe_index = stripe_index;
3877                         stripe_index = find_live_mirror(map, stripe_index,
3878                                               map->sub_stripes, stripe_index +
3879                                               current->pid % map->sub_stripes);
3880                         mirror_num = stripe_index - old_stripe_index + 1;
3881                 }
3882         } else {
3883                 /*
3884                  * after this do_div call, stripe_nr is the number of stripes
3885                  * on this device we have to walk to find the data, and
3886                  * stripe_index is the number of our device in the stripe array
3887                  */
3888                 stripe_index = do_div(stripe_nr, map->num_stripes);
3889                 mirror_num = stripe_index + 1;
3890         }
3891         BUG_ON(stripe_index >= map->num_stripes);
3892
3893         bbio = kzalloc(btrfs_bio_size(num_stripes), GFP_NOFS);
3894         if (!bbio) {
3895                 ret = -ENOMEM;
3896                 goto out;
3897         }
3898         atomic_set(&bbio->error, 0);
3899
3900         if (rw & REQ_DISCARD) {
3901                 int factor = 0;
3902                 int sub_stripes = 0;
3903                 u64 stripes_per_dev = 0;
3904                 u32 remaining_stripes = 0;
3905                 u32 last_stripe = 0;
3906
3907                 if (map->type &
3908                     (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
3909                         if (map->type & BTRFS_BLOCK_GROUP_RAID0)
3910                                 sub_stripes = 1;
3911                         else
3912                                 sub_stripes = map->sub_stripes;
3913
3914                         factor = map->num_stripes / sub_stripes;
3915                         stripes_per_dev = div_u64_rem(stripe_nr_end -
3916                                                       stripe_nr_orig,
3917                                                       factor,
3918                                                       &remaining_stripes);
3919                         div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
3920                         last_stripe *= sub_stripes;
3921                 }
3922
3923                 for (i = 0; i < num_stripes; i++) {
3924                         bbio->stripes[i].physical =
3925                                 map->stripes[stripe_index].physical +
3926                                 stripe_offset + stripe_nr * map->stripe_len;
3927                         bbio->stripes[i].dev = map->stripes[stripe_index].dev;
3928
3929                         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
3930                                          BTRFS_BLOCK_GROUP_RAID10)) {
3931                                 bbio->stripes[i].length = stripes_per_dev *
3932                                                           map->stripe_len;
3933
3934                                 if (i / sub_stripes < remaining_stripes)
3935                                         bbio->stripes[i].length +=
3936                                                 map->stripe_len;
3937
3938                                 /*
3939                                  * Special for the first stripe and
3940                                  * the last stripe:
3941                                  *
3942                                  * |-------|...|-------|
3943                                  *     |----------|
3944                                  *    off     end_off
3945                                  */
3946                                 if (i < sub_stripes)
3947                                         bbio->stripes[i].length -=
3948                                                 stripe_offset;
3949
3950                                 if (stripe_index >= last_stripe &&
3951                                     stripe_index <= (last_stripe +
3952                                                      sub_stripes - 1))
3953                                         bbio->stripes[i].length -=
3954                                                 stripe_end_offset;
3955
3956                                 if (i == sub_stripes - 1)
3957                                         stripe_offset = 0;
3958                         } else
3959                                 bbio->stripes[i].length = *length;
3960
3961                         stripe_index++;
3962                         if (stripe_index == map->num_stripes) {
3963                                 /* This could only happen for RAID0/10 */
3964                                 stripe_index = 0;
3965                                 stripe_nr++;
3966                         }
3967                 }
3968         } else {
3969                 for (i = 0; i < num_stripes; i++) {
3970                         bbio->stripes[i].physical =
3971                                 map->stripes[stripe_index].physical +
3972                                 stripe_offset +
3973                                 stripe_nr * map->stripe_len;
3974                         bbio->stripes[i].dev =
3975                                 map->stripes[stripe_index].dev;
3976                         stripe_index++;
3977                 }
3978         }
3979
3980         if (rw & REQ_WRITE) {
3981                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
3982                                  BTRFS_BLOCK_GROUP_RAID10 |
3983                                  BTRFS_BLOCK_GROUP_DUP)) {
3984                         max_errors = 1;
3985                 }
3986         }
3987
3988         *bbio_ret = bbio;
3989         bbio->num_stripes = num_stripes;
3990         bbio->max_errors = max_errors;
3991         bbio->mirror_num = mirror_num;
3992 out:
3993         free_extent_map(em);
3994         return ret;
3995 }
3996
3997 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
3998                       u64 logical, u64 *length,
3999                       struct btrfs_bio **bbio_ret, int mirror_num)
4000 {
4001         return __btrfs_map_block(map_tree, rw, logical, length, bbio_ret,
4002                                  mirror_num);
4003 }
4004
4005 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
4006                      u64 chunk_start, u64 physical, u64 devid,
4007                      u64 **logical, int *naddrs, int *stripe_len)
4008 {
4009         struct extent_map_tree *em_tree = &map_tree->map_tree;
4010         struct extent_map *em;
4011         struct map_lookup *map;
4012         u64 *buf;
4013         u64 bytenr;
4014         u64 length;
4015         u64 stripe_nr;
4016         int i, j, nr = 0;
4017
4018         read_lock(&em_tree->lock);
4019         em = lookup_extent_mapping(em_tree, chunk_start, 1);
4020         read_unlock(&em_tree->lock);
4021
4022         BUG_ON(!em || em->start != chunk_start);
4023         map = (struct map_lookup *)em->bdev;
4024
4025         length = em->len;
4026         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
4027                 do_div(length, map->num_stripes / map->sub_stripes);
4028         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
4029                 do_div(length, map->num_stripes);
4030
4031         buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
4032         BUG_ON(!buf); /* -ENOMEM */
4033
4034         for (i = 0; i < map->num_stripes; i++) {
4035                 if (devid && map->stripes[i].dev->devid != devid)
4036                         continue;
4037                 if (map->stripes[i].physical > physical ||
4038                     map->stripes[i].physical + length <= physical)
4039                         continue;
4040
4041                 stripe_nr = physical - map->stripes[i].physical;
4042                 do_div(stripe_nr, map->stripe_len);
4043
4044                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
4045                         stripe_nr = stripe_nr * map->num_stripes + i;
4046                         do_div(stripe_nr, map->sub_stripes);
4047                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
4048                         stripe_nr = stripe_nr * map->num_stripes + i;
4049                 }
4050                 bytenr = chunk_start + stripe_nr * map->stripe_len;
4051                 WARN_ON(nr >= map->num_stripes);
4052                 for (j = 0; j < nr; j++) {
4053                         if (buf[j] == bytenr)
4054                                 break;
4055                 }
4056                 if (j == nr) {
4057                         WARN_ON(nr >= map->num_stripes);
4058                         buf[nr++] = bytenr;
4059                 }
4060         }
4061
4062         *logical = buf;
4063         *naddrs = nr;
4064         *stripe_len = map->stripe_len;
4065
4066         free_extent_map(em);
4067         return 0;
4068 }
4069
4070 static void *merge_stripe_index_into_bio_private(void *bi_private,
4071                                                  unsigned int stripe_index)
4072 {
4073         /*
4074          * with single, dup, RAID0, RAID1 and RAID10, stripe_index is
4075          * at most 1.
4076          * The alternative solution (instead of stealing bits from the
4077          * pointer) would be to allocate an intermediate structure
4078          * that contains the old private pointer plus the stripe_index.
4079          */
4080         BUG_ON((((uintptr_t)bi_private) & 3) != 0);
4081         BUG_ON(stripe_index > 3);
4082         return (void *)(((uintptr_t)bi_private) | stripe_index);
4083 }
4084
4085 static struct btrfs_bio *extract_bbio_from_bio_private(void *bi_private)
4086 {
4087         return (struct btrfs_bio *)(((uintptr_t)bi_private) & ~((uintptr_t)3));
4088 }
4089
4090 static unsigned int extract_stripe_index_from_bio_private(void *bi_private)
4091 {
4092         return (unsigned int)((uintptr_t)bi_private) & 3;
4093 }
4094
4095 static void btrfs_end_bio(struct bio *bio, int err)
4096 {
4097         struct btrfs_bio *bbio = extract_bbio_from_bio_private(bio->bi_private);
4098         int is_orig_bio = 0;
4099
4100         if (err) {
4101                 atomic_inc(&bbio->error);
4102                 if (err == -EIO || err == -EREMOTEIO) {
4103                         unsigned int stripe_index =
4104                                 extract_stripe_index_from_bio_private(
4105                                         bio->bi_private);
4106                         struct btrfs_device *dev;
4107
4108                         BUG_ON(stripe_index >= bbio->num_stripes);
4109                         dev = bbio->stripes[stripe_index].dev;
4110                         if (dev->bdev) {
4111                                 if (bio->bi_rw & WRITE)
4112                                         btrfs_dev_stat_inc(dev,
4113                                                 BTRFS_DEV_STAT_WRITE_ERRS);
4114                                 else
4115                                         btrfs_dev_stat_inc(dev,
4116                                                 BTRFS_DEV_STAT_READ_ERRS);
4117                                 if ((bio->bi_rw & WRITE_FLUSH) == WRITE_FLUSH)
4118                                         btrfs_dev_stat_inc(dev,
4119                                                 BTRFS_DEV_STAT_FLUSH_ERRS);
4120                                 btrfs_dev_stat_print_on_error(dev);
4121                         }
4122                 }
4123         }
4124
4125         if (bio == bbio->orig_bio)
4126                 is_orig_bio = 1;
4127
4128         if (atomic_dec_and_test(&bbio->stripes_pending)) {
4129                 if (!is_orig_bio) {
4130                         bio_put(bio);
4131                         bio = bbio->orig_bio;
4132                 }
4133                 bio->bi_private = bbio->private;
4134                 bio->bi_end_io = bbio->end_io;
4135                 bio->bi_bdev = (struct block_device *)
4136                                         (unsigned long)bbio->mirror_num;
4137                 /* only send an error to the higher layers if it is
4138                  * beyond the tolerance of the multi-bio
4139                  */
4140                 if (atomic_read(&bbio->error) > bbio->max_errors) {
4141                         err = -EIO;
4142                 } else {
4143                         /*
4144                          * this bio is actually up to date, we didn't
4145                          * go over the max number of errors
4146                          */
4147                         set_bit(BIO_UPTODATE, &bio->bi_flags);
4148                         err = 0;
4149                 }
4150                 kfree(bbio);
4151
4152                 bio_endio(bio, err);
4153         } else if (!is_orig_bio) {
4154                 bio_put(bio);
4155         }
4156 }
4157
4158 struct async_sched {
4159         struct bio *bio;
4160         int rw;
4161         struct btrfs_fs_info *info;
4162         struct btrfs_work work;
4163 };
4164
4165 /*
4166  * see run_scheduled_bios for a description of why bios are collected for
4167  * async submit.
4168  *
4169  * This will add one bio to the pending list for a device and make sure
4170  * the work struct is scheduled.
4171  */
4172 static noinline void schedule_bio(struct btrfs_root *root,
4173                                  struct btrfs_device *device,
4174                                  int rw, struct bio *bio)
4175 {
4176         int should_queue = 1;
4177         struct btrfs_pending_bios *pending_bios;
4178
4179         /* don't bother with additional async steps for reads, right now */
4180         if (!(rw & REQ_WRITE)) {
4181                 bio_get(bio);
4182                 btrfsic_submit_bio(rw, bio);
4183                 bio_put(bio);
4184                 return;
4185         }
4186
4187         /*
4188          * nr_async_bios allows us to reliably return congestion to the
4189          * higher layers.  Otherwise, the async bio makes it appear we have
4190          * made progress against dirty pages when we've really just put it
4191          * on a queue for later
4192          */
4193         atomic_inc(&root->fs_info->nr_async_bios);
4194         WARN_ON(bio->bi_next);
4195         bio->bi_next = NULL;
4196         bio->bi_rw |= rw;
4197
4198         spin_lock(&device->io_lock);
4199         if (bio->bi_rw & REQ_SYNC)
4200                 pending_bios = &device->pending_sync_bios;
4201         else
4202                 pending_bios = &device->pending_bios;
4203
4204         if (pending_bios->tail)
4205                 pending_bios->tail->bi_next = bio;
4206
4207         pending_bios->tail = bio;
4208         if (!pending_bios->head)
4209                 pending_bios->head = bio;
4210         if (device->running_pending)
4211                 should_queue = 0;
4212
4213         spin_unlock(&device->io_lock);
4214
4215         if (should_queue)
4216                 btrfs_queue_worker(&root->fs_info->submit_workers,
4217                                    &device->work);
4218 }
4219
4220 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
4221                   int mirror_num, int async_submit)
4222 {
4223         struct btrfs_mapping_tree *map_tree;
4224         struct btrfs_device *dev;
4225         struct bio *first_bio = bio;
4226         u64 logical = (u64)bio->bi_sector << 9;
4227         u64 length = 0;
4228         u64 map_length;
4229         int ret;
4230         int dev_nr = 0;
4231         int total_devs = 1;
4232         struct btrfs_bio *bbio = NULL;
4233
4234         length = bio->bi_size;
4235         map_tree = &root->fs_info->mapping_tree;
4236         map_length = length;
4237
4238         ret = btrfs_map_block(map_tree, rw, logical, &map_length, &bbio,
4239                               mirror_num);
4240         if (ret) /* -ENOMEM */
4241                 return ret;
4242
4243         total_devs = bbio->num_stripes;
4244         if (map_length < length) {
4245                 printk(KERN_CRIT "btrfs: mapping failed logical %llu bio len %llu "
4246                        "len %llu\n", (unsigned long long)logical,
4247                        (unsigned long long)length,
4248                        (unsigned long long)map_length);
4249                 BUG();
4250         }
4251
4252         bbio->orig_bio = first_bio;
4253         bbio->private = first_bio->bi_private;
4254         bbio->end_io = first_bio->bi_end_io;
4255         atomic_set(&bbio->stripes_pending, bbio->num_stripes);
4256
4257         while (dev_nr < total_devs) {
4258                 if (dev_nr < total_devs - 1) {
4259                         bio = bio_clone(first_bio, GFP_NOFS);
4260                         BUG_ON(!bio); /* -ENOMEM */
4261                 } else {
4262                         bio = first_bio;
4263                 }
4264                 bio->bi_private = bbio;
4265                 bio->bi_private = merge_stripe_index_into_bio_private(
4266                                 bio->bi_private, (unsigned int)dev_nr);
4267                 bio->bi_end_io = btrfs_end_bio;
4268                 bio->bi_sector = bbio->stripes[dev_nr].physical >> 9;
4269                 dev = bbio->stripes[dev_nr].dev;
4270                 if (dev && dev->bdev && (rw != WRITE || dev->writeable)) {
4271 #ifdef DEBUG
4272                         struct rcu_string *name;
4273
4274                         rcu_read_lock();
4275                         name = rcu_dereference(dev->name);
4276                         pr_debug("btrfs_map_bio: rw %d, secor=%llu, dev=%lu "
4277                                  "(%s id %llu), size=%u\n", rw,
4278                                  (u64)bio->bi_sector, (u_long)dev->bdev->bd_dev,
4279                                  name->str, dev->devid, bio->bi_size);
4280                         rcu_read_unlock();
4281 #endif
4282                         bio->bi_bdev = dev->bdev;
4283                         if (async_submit)
4284                                 schedule_bio(root, dev, rw, bio);
4285                         else
4286                                 btrfsic_submit_bio(rw, bio);
4287                 } else {
4288                         bio->bi_bdev = root->fs_info->fs_devices->latest_bdev;
4289                         bio->bi_sector = logical >> 9;
4290                         bio_endio(bio, -EIO);
4291                 }
4292                 dev_nr++;
4293         }
4294         return 0;
4295 }
4296
4297 struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
4298                                        u8 *uuid, u8 *fsid)
4299 {
4300         struct btrfs_device *device;
4301         struct btrfs_fs_devices *cur_devices;
4302
4303         cur_devices = root->fs_info->fs_devices;
4304         while (cur_devices) {
4305                 if (!fsid ||
4306                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
4307                         device = __find_device(&cur_devices->devices,
4308                                                devid, uuid);
4309                         if (device)
4310                                 return device;
4311                 }
4312                 cur_devices = cur_devices->seed;
4313         }
4314         return NULL;
4315 }
4316
4317 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
4318                                             u64 devid, u8 *dev_uuid)
4319 {
4320         struct btrfs_device *device;
4321         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
4322
4323         device = kzalloc(sizeof(*device), GFP_NOFS);
4324         if (!device)
4325                 return NULL;
4326         list_add(&device->dev_list,
4327                  &fs_devices->devices);
4328         device->dev_root = root->fs_info->dev_root;
4329         device->devid = devid;
4330         device->work.func = pending_bios_fn;
4331         device->fs_devices = fs_devices;
4332         device->missing = 1;
4333         fs_devices->num_devices++;
4334         fs_devices->missing_devices++;
4335         spin_lock_init(&device->io_lock);
4336         INIT_LIST_HEAD(&device->dev_alloc_list);
4337         memcpy(device->uuid, dev_uuid, BTRFS_UUID_SIZE);
4338         return device;
4339 }
4340
4341 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
4342                           struct extent_buffer *leaf,
4343                           struct btrfs_chunk *chunk)
4344 {
4345         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
4346         struct map_lookup *map;
4347         struct extent_map *em;
4348         u64 logical;
4349         u64 length;
4350         u64 devid;
4351         u8 uuid[BTRFS_UUID_SIZE];
4352         int num_stripes;
4353         int ret;
4354         int i;
4355
4356         logical = key->offset;
4357         length = btrfs_chunk_length(leaf, chunk);
4358
4359         read_lock(&map_tree->map_tree.lock);
4360         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
4361         read_unlock(&map_tree->map_tree.lock);
4362
4363         /* already mapped? */
4364         if (em && em->start <= logical && em->start + em->len > logical) {
4365                 free_extent_map(em);
4366                 return 0;
4367         } else if (em) {
4368                 free_extent_map(em);
4369         }
4370
4371         em = alloc_extent_map();
4372         if (!em)
4373                 return -ENOMEM;
4374         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
4375         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
4376         if (!map) {
4377                 free_extent_map(em);
4378                 return -ENOMEM;
4379         }
4380
4381         em->bdev = (struct block_device *)map;
4382         em->start = logical;
4383         em->len = length;
4384         em->block_start = 0;
4385         em->block_len = em->len;
4386
4387         map->num_stripes = num_stripes;
4388         map->io_width = btrfs_chunk_io_width(leaf, chunk);
4389         map->io_align = btrfs_chunk_io_align(leaf, chunk);
4390         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
4391         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
4392         map->type = btrfs_chunk_type(leaf, chunk);
4393         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
4394         for (i = 0; i < num_stripes; i++) {
4395                 map->stripes[i].physical =
4396                         btrfs_stripe_offset_nr(leaf, chunk, i);
4397                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
4398                 read_extent_buffer(leaf, uuid, (unsigned long)
4399                                    btrfs_stripe_dev_uuid_nr(chunk, i),
4400                                    BTRFS_UUID_SIZE);
4401                 map->stripes[i].dev = btrfs_find_device(root, devid, uuid,
4402                                                         NULL);
4403                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
4404                         kfree(map);
4405                         free_extent_map(em);
4406                         return -EIO;
4407                 }
4408                 if (!map->stripes[i].dev) {
4409                         map->stripes[i].dev =
4410                                 add_missing_dev(root, devid, uuid);
4411                         if (!map->stripes[i].dev) {
4412                                 kfree(map);
4413                                 free_extent_map(em);
4414                                 return -EIO;
4415                         }
4416                 }
4417                 map->stripes[i].dev->in_fs_metadata = 1;
4418         }
4419
4420         write_lock(&map_tree->map_tree.lock);
4421         ret = add_extent_mapping(&map_tree->map_tree, em);
4422         write_unlock(&map_tree->map_tree.lock);
4423         BUG_ON(ret); /* Tree corruption */
4424         free_extent_map(em);
4425
4426         return 0;
4427 }
4428
4429 static void fill_device_from_item(struct extent_buffer *leaf,
4430                                  struct btrfs_dev_item *dev_item,
4431                                  struct btrfs_device *device)
4432 {
4433         unsigned long ptr;
4434
4435         device->devid = btrfs_device_id(leaf, dev_item);
4436         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
4437         device->total_bytes = device->disk_total_bytes;
4438         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
4439         device->type = btrfs_device_type(leaf, dev_item);
4440         device->io_align = btrfs_device_io_align(leaf, dev_item);
4441         device->io_width = btrfs_device_io_width(leaf, dev_item);
4442         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
4443
4444         ptr = (unsigned long)btrfs_device_uuid(dev_item);
4445         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
4446 }
4447
4448 static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
4449 {
4450         struct btrfs_fs_devices *fs_devices;
4451         int ret;
4452
4453         BUG_ON(!mutex_is_locked(&uuid_mutex));
4454
4455         fs_devices = root->fs_info->fs_devices->seed;
4456         while (fs_devices) {
4457                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
4458                         ret = 0;
4459                         goto out;
4460                 }
4461                 fs_devices = fs_devices->seed;
4462         }
4463
4464         fs_devices = find_fsid(fsid);
4465         if (!fs_devices) {
4466                 ret = -ENOENT;
4467                 goto out;
4468         }
4469
4470         fs_devices = clone_fs_devices(fs_devices);
4471         if (IS_ERR(fs_devices)) {
4472                 ret = PTR_ERR(fs_devices);
4473                 goto out;
4474         }
4475
4476         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
4477                                    root->fs_info->bdev_holder);
4478         if (ret) {
4479                 free_fs_devices(fs_devices);
4480                 goto out;
4481         }
4482
4483         if (!fs_devices->seeding) {
4484                 __btrfs_close_devices(fs_devices);
4485                 free_fs_devices(fs_devices);
4486                 ret = -EINVAL;
4487                 goto out;
4488         }
4489
4490         fs_devices->seed = root->fs_info->fs_devices->seed;
4491         root->fs_info->fs_devices->seed = fs_devices;
4492 out:
4493         return ret;
4494 }
4495
4496 static int read_one_dev(struct btrfs_root *root,
4497                         struct extent_buffer *leaf,
4498                         struct btrfs_dev_item *dev_item)
4499 {
4500         struct btrfs_device *device;
4501         u64 devid;
4502         int ret;
4503         u8 fs_uuid[BTRFS_UUID_SIZE];
4504         u8 dev_uuid[BTRFS_UUID_SIZE];
4505
4506         devid = btrfs_device_id(leaf, dev_item);
4507         read_extent_buffer(leaf, dev_uuid,
4508                            (unsigned long)btrfs_device_uuid(dev_item),
4509                            BTRFS_UUID_SIZE);
4510         read_extent_buffer(leaf, fs_uuid,
4511                            (unsigned long)btrfs_device_fsid(dev_item),
4512                            BTRFS_UUID_SIZE);
4513
4514         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
4515                 ret = open_seed_devices(root, fs_uuid);
4516                 if (ret && !btrfs_test_opt(root, DEGRADED))
4517                         return ret;
4518         }
4519
4520         device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
4521         if (!device || !device->bdev) {
4522                 if (!btrfs_test_opt(root, DEGRADED))
4523                         return -EIO;
4524
4525                 if (!device) {
4526                         printk(KERN_WARNING "warning devid %llu missing\n",
4527                                (unsigned long long)devid);
4528                         device = add_missing_dev(root, devid, dev_uuid);
4529                         if (!device)
4530                                 return -ENOMEM;
4531                 } else if (!device->missing) {
4532                         /*
4533                          * this happens when a device that was properly setup
4534                          * in the device info lists suddenly goes bad.
4535                          * device->bdev is NULL, and so we have to set
4536                          * device->missing to one here
4537                          */
4538                         root->fs_info->fs_devices->missing_devices++;
4539                         device->missing = 1;
4540                 }
4541         }
4542
4543         if (device->fs_devices != root->fs_info->fs_devices) {
4544                 BUG_ON(device->writeable);
4545                 if (device->generation !=
4546                     btrfs_device_generation(leaf, dev_item))
4547                         return -EINVAL;
4548         }
4549
4550         fill_device_from_item(leaf, dev_item, device);
4551         device->dev_root = root->fs_info->dev_root;
4552         device->in_fs_metadata = 1;
4553         if (device->writeable) {
4554                 device->fs_devices->total_rw_bytes += device->total_bytes;
4555                 spin_lock(&root->fs_info->free_chunk_lock);
4556                 root->fs_info->free_chunk_space += device->total_bytes -
4557                         device->bytes_used;
4558                 spin_unlock(&root->fs_info->free_chunk_lock);
4559         }
4560         ret = 0;
4561         return ret;
4562 }
4563
4564 int btrfs_read_sys_array(struct btrfs_root *root)
4565 {
4566         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
4567         struct extent_buffer *sb;
4568         struct btrfs_disk_key *disk_key;
4569         struct btrfs_chunk *chunk;
4570         u8 *ptr;
4571         unsigned long sb_ptr;
4572         int ret = 0;
4573         u32 num_stripes;
4574         u32 array_size;
4575         u32 len = 0;
4576         u32 cur;
4577         struct btrfs_key key;
4578
4579         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
4580                                           BTRFS_SUPER_INFO_SIZE);
4581         if (!sb)
4582                 return -ENOMEM;
4583         btrfs_set_buffer_uptodate(sb);
4584         btrfs_set_buffer_lockdep_class(root->root_key.objectid, sb, 0);
4585         /*
4586          * The sb extent buffer is artifical and just used to read the system array.
4587          * btrfs_set_buffer_uptodate() call does not properly mark all it's
4588          * pages up-to-date when the page is larger: extent does not cover the
4589          * whole page and consequently check_page_uptodate does not find all
4590          * the page's extents up-to-date (the hole beyond sb),
4591          * write_extent_buffer then triggers a WARN_ON.
4592          *
4593          * Regular short extents go through mark_extent_buffer_dirty/writeback cycle,
4594          * but sb spans only this function. Add an explicit SetPageUptodate call
4595          * to silence the warning eg. on PowerPC 64.
4596          */
4597         if (PAGE_CACHE_SIZE > BTRFS_SUPER_INFO_SIZE)
4598                 SetPageUptodate(sb->pages[0]);
4599
4600         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
4601         array_size = btrfs_super_sys_array_size(super_copy);
4602
4603         ptr = super_copy->sys_chunk_array;
4604         sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
4605         cur = 0;
4606
4607         while (cur < array_size) {
4608                 disk_key = (struct btrfs_disk_key *)ptr;
4609                 btrfs_disk_key_to_cpu(&key, disk_key);
4610
4611                 len = sizeof(*disk_key); ptr += len;
4612                 sb_ptr += len;
4613                 cur += len;
4614
4615                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
4616                         chunk = (struct btrfs_chunk *)sb_ptr;
4617                         ret = read_one_chunk(root, &key, sb, chunk);
4618                         if (ret)
4619                                 break;
4620                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
4621                         len = btrfs_chunk_item_size(num_stripes);
4622                 } else {
4623                         ret = -EIO;
4624                         break;
4625                 }
4626                 ptr += len;
4627                 sb_ptr += len;
4628                 cur += len;
4629         }
4630         free_extent_buffer(sb);
4631         return ret;
4632 }
4633
4634 int btrfs_read_chunk_tree(struct btrfs_root *root)
4635 {
4636         struct btrfs_path *path;
4637         struct extent_buffer *leaf;
4638         struct btrfs_key key;
4639         struct btrfs_key found_key;
4640         int ret;
4641         int slot;
4642
4643         root = root->fs_info->chunk_root;
4644
4645         path = btrfs_alloc_path();
4646         if (!path)
4647                 return -ENOMEM;
4648
4649         mutex_lock(&uuid_mutex);
4650         lock_chunks(root);
4651
4652         /* first we search for all of the device items, and then we
4653          * read in all of the chunk items.  This way we can create chunk
4654          * mappings that reference all of the devices that are afound
4655          */
4656         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
4657         key.offset = 0;
4658         key.type = 0;
4659 again:
4660         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4661         if (ret < 0)
4662                 goto error;
4663         while (1) {
4664                 leaf = path->nodes[0];
4665                 slot = path->slots[0];
4666                 if (slot >= btrfs_header_nritems(leaf)) {
4667                         ret = btrfs_next_leaf(root, path);
4668                         if (ret == 0)
4669                                 continue;
4670                         if (ret < 0)
4671                                 goto error;
4672                         break;
4673                 }
4674                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
4675                 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
4676                         if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
4677                                 break;
4678                         if (found_key.type == BTRFS_DEV_ITEM_KEY) {
4679                                 struct btrfs_dev_item *dev_item;
4680                                 dev_item = btrfs_item_ptr(leaf, slot,
4681                                                   struct btrfs_dev_item);
4682                                 ret = read_one_dev(root, leaf, dev_item);
4683                                 if (ret)
4684                                         goto error;
4685                         }
4686                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
4687                         struct btrfs_chunk *chunk;
4688                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
4689                         ret = read_one_chunk(root, &found_key, leaf, chunk);
4690                         if (ret)
4691                                 goto error;
4692                 }
4693                 path->slots[0]++;
4694         }
4695         if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
4696                 key.objectid = 0;
4697                 btrfs_release_path(path);
4698                 goto again;
4699         }
4700         ret = 0;
4701 error:
4702         unlock_chunks(root);
4703         mutex_unlock(&uuid_mutex);
4704
4705         btrfs_free_path(path);
4706         return ret;
4707 }
4708
4709 static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
4710 {
4711         int i;
4712
4713         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
4714                 btrfs_dev_stat_reset(dev, i);
4715 }
4716
4717 int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info)
4718 {
4719         struct btrfs_key key;
4720         struct btrfs_key found_key;
4721         struct btrfs_root *dev_root = fs_info->dev_root;
4722         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
4723         struct extent_buffer *eb;
4724         int slot;
4725         int ret = 0;
4726         struct btrfs_device *device;
4727         struct btrfs_path *path = NULL;
4728         int i;
4729
4730         path = btrfs_alloc_path();
4731         if (!path) {
4732                 ret = -ENOMEM;
4733                 goto out;
4734         }
4735
4736         mutex_lock(&fs_devices->device_list_mutex);
4737         list_for_each_entry(device, &fs_devices->devices, dev_list) {
4738                 int item_size;
4739                 struct btrfs_dev_stats_item *ptr;
4740
4741                 key.objectid = 0;
4742                 key.type = BTRFS_DEV_STATS_KEY;
4743                 key.offset = device->devid;
4744                 ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
4745                 if (ret) {
4746                         __btrfs_reset_dev_stats(device);
4747                         device->dev_stats_valid = 1;
4748                         btrfs_release_path(path);
4749                         continue;
4750                 }
4751                 slot = path->slots[0];
4752                 eb = path->nodes[0];
4753                 btrfs_item_key_to_cpu(eb, &found_key, slot);
4754                 item_size = btrfs_item_size_nr(eb, slot);
4755
4756                 ptr = btrfs_item_ptr(eb, slot,
4757                                      struct btrfs_dev_stats_item);
4758
4759                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
4760                         if (item_size >= (1 + i) * sizeof(__le64))
4761                                 btrfs_dev_stat_set(device, i,
4762                                         btrfs_dev_stats_value(eb, ptr, i));
4763                         else
4764                                 btrfs_dev_stat_reset(device, i);
4765                 }
4766
4767                 device->dev_stats_valid = 1;
4768                 btrfs_dev_stat_print_on_load(device);
4769                 btrfs_release_path(path);
4770         }
4771         mutex_unlock(&fs_devices->device_list_mutex);
4772
4773 out:
4774         btrfs_free_path(path);
4775         return ret < 0 ? ret : 0;
4776 }
4777
4778 static int update_dev_stat_item(struct btrfs_trans_handle *trans,
4779                                 struct btrfs_root *dev_root,
4780                                 struct btrfs_device *device)
4781 {
4782         struct btrfs_path *path;
4783         struct btrfs_key key;
4784         struct extent_buffer *eb;
4785         struct btrfs_dev_stats_item *ptr;
4786         int ret;
4787         int i;
4788
4789         key.objectid = 0;
4790         key.type = BTRFS_DEV_STATS_KEY;
4791         key.offset = device->devid;
4792
4793         path = btrfs_alloc_path();
4794         BUG_ON(!path);
4795         ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
4796         if (ret < 0) {
4797                 printk_in_rcu(KERN_WARNING "btrfs: error %d while searching for dev_stats item for device %s!\n",
4798                               ret, rcu_str_deref(device->name));
4799                 goto out;
4800         }
4801
4802         if (ret == 0 &&
4803             btrfs_item_size_nr(path->nodes[0], path->slots[0]) < sizeof(*ptr)) {
4804                 /* need to delete old one and insert a new one */
4805                 ret = btrfs_del_item(trans, dev_root, path);
4806                 if (ret != 0) {
4807                         printk_in_rcu(KERN_WARNING "btrfs: delete too small dev_stats item for device %s failed %d!\n",
4808                                       rcu_str_deref(device->name), ret);
4809                         goto out;
4810                 }
4811                 ret = 1;
4812         }
4813
4814         if (ret == 1) {
4815                 /* need to insert a new item */
4816                 btrfs_release_path(path);
4817                 ret = btrfs_insert_empty_item(trans, dev_root, path,
4818                                               &key, sizeof(*ptr));
4819                 if (ret < 0) {
4820                         printk_in_rcu(KERN_WARNING "btrfs: insert dev_stats item for device %s failed %d!\n",
4821                                       rcu_str_deref(device->name), ret);
4822                         goto out;
4823                 }
4824         }
4825
4826         eb = path->nodes[0];
4827         ptr = btrfs_item_ptr(eb, path->slots[0], struct btrfs_dev_stats_item);
4828         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
4829                 btrfs_set_dev_stats_value(eb, ptr, i,
4830                                           btrfs_dev_stat_read(device, i));
4831         btrfs_mark_buffer_dirty(eb);
4832
4833 out:
4834         btrfs_free_path(path);
4835         return ret;
4836 }
4837
4838 /*
4839  * called from commit_transaction. Writes all changed device stats to disk.
4840  */
4841 int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
4842                         struct btrfs_fs_info *fs_info)
4843 {
4844         struct btrfs_root *dev_root = fs_info->dev_root;
4845         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
4846         struct btrfs_device *device;
4847         int ret = 0;
4848
4849         mutex_lock(&fs_devices->device_list_mutex);
4850         list_for_each_entry(device, &fs_devices->devices, dev_list) {
4851                 if (!device->dev_stats_valid || !device->dev_stats_dirty)
4852                         continue;
4853
4854                 ret = update_dev_stat_item(trans, dev_root, device);
4855                 if (!ret)
4856                         device->dev_stats_dirty = 0;
4857         }
4858         mutex_unlock(&fs_devices->device_list_mutex);
4859
4860         return ret;
4861 }
4862
4863 void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index)
4864 {
4865         btrfs_dev_stat_inc(dev, index);
4866         btrfs_dev_stat_print_on_error(dev);
4867 }
4868
4869 void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
4870 {
4871         if (!dev->dev_stats_valid)
4872                 return;
4873         printk_ratelimited_in_rcu(KERN_ERR
4874                            "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
4875                            rcu_str_deref(dev->name),
4876                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
4877                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
4878                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
4879                            btrfs_dev_stat_read(dev,
4880                                                BTRFS_DEV_STAT_CORRUPTION_ERRS),
4881                            btrfs_dev_stat_read(dev,
4882                                                BTRFS_DEV_STAT_GENERATION_ERRS));
4883 }
4884
4885 static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
4886 {
4887         int i;
4888
4889         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
4890                 if (btrfs_dev_stat_read(dev, i) != 0)
4891                         break;
4892         if (i == BTRFS_DEV_STAT_VALUES_MAX)
4893                 return; /* all values == 0, suppress message */
4894
4895         printk_in_rcu(KERN_INFO "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
4896                rcu_str_deref(dev->name),
4897                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
4898                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
4899                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
4900                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
4901                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
4902 }
4903
4904 int btrfs_get_dev_stats(struct btrfs_root *root,
4905                         struct btrfs_ioctl_get_dev_stats *stats)
4906 {
4907         struct btrfs_device *dev;
4908         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
4909         int i;
4910
4911         mutex_lock(&fs_devices->device_list_mutex);
4912         dev = btrfs_find_device(root, stats->devid, NULL, NULL);
4913         mutex_unlock(&fs_devices->device_list_mutex);
4914
4915         if (!dev) {
4916                 printk(KERN_WARNING
4917                        "btrfs: get dev_stats failed, device not found\n");
4918                 return -ENODEV;
4919         } else if (!dev->dev_stats_valid) {
4920                 printk(KERN_WARNING
4921                        "btrfs: get dev_stats failed, not yet valid\n");
4922                 return -ENODEV;
4923         } else if (stats->flags & BTRFS_DEV_STATS_RESET) {
4924                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
4925                         if (stats->nr_items > i)
4926                                 stats->values[i] =
4927                                         btrfs_dev_stat_read_and_reset(dev, i);
4928                         else
4929                                 btrfs_dev_stat_reset(dev, i);
4930                 }
4931         } else {
4932                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
4933                         if (stats->nr_items > i)
4934                                 stats->values[i] = btrfs_dev_stat_read(dev, i);
4935         }
4936         if (stats->nr_items > BTRFS_DEV_STAT_VALUES_MAX)
4937                 stats->nr_items = BTRFS_DEV_STAT_VALUES_MAX;
4938         return 0;
4939 }