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 <asm/div64.h>
  27 #include "compat.h"
  28 #include "ctree.h"
  29 #include "extent_map.h"
  30 #include "disk-io.h"
  31 #include "transaction.h"
  32 #include "print-tree.h"
  33 #include "volumes.h"
  34 #include "async-thread.h"
  35
  36 static int init_first_rw_device(struct btrfs_trans_handle *trans,
  37                                 struct btrfs_root *root,
  38                                 struct btrfs_device *device);
  39 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
  40
  41 static DEFINE_MUTEX(uuid_mutex);
  42 static LIST_HEAD(fs_uuids);
  43
  44 static void lock_chunks(struct btrfs_root *root)
  45 {
  46         mutex_lock(&root->fs_info->chunk_mutex);
  47 }
  48
  49 static void unlock_chunks(struct btrfs_root *root)
  50 {
  51         mutex_unlock(&root->fs_info->chunk_mutex);
  52 }
  53
  54 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
  55 {
  56         struct btrfs_device *device;
  57         WARN_ON(fs_devices->opened);
  58         while (!list_empty(&fs_devices->devices)) {
  59                 device = list_entry(fs_devices->devices.next,
  60                                     struct btrfs_device, dev_list);
  61                 list_del(&device->dev_list);
  62                 kfree(device->name);
  63                 kfree(device);
  64         }
  65         kfree(fs_devices);
  66 }
  67
  68 int btrfs_cleanup_fs_uuids(void)
  69 {
  70         struct btrfs_fs_devices *fs_devices;
  71
  72         while (!list_empty(&fs_uuids)) {
  73                 fs_devices = list_entry(fs_uuids.next,
  74                                         struct btrfs_fs_devices, list);
  75                 list_del(&fs_devices->list);
  76                 free_fs_devices(fs_devices);
  77         }
  78         return 0;
  79 }
  80
  81 static noinline struct btrfs_device *__find_device(struct list_head *head,
  82                                                    u64 devid, u8 *uuid)
  83 {
  84         struct btrfs_device *dev;
  85
  86         list_for_each_entry(dev, head, dev_list) {
  87                 if (dev->devid == devid &&
  88                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
  89                         return dev;
  90                 }
  91         }
  92         return NULL;
  93 }
  94
  95 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
  96 {
  97         struct btrfs_fs_devices *fs_devices;
  98
  99         list_for_each_entry(fs_devices, &fs_uuids, list) {
 100                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
 101                         return fs_devices;
 102         }
 103         return NULL;
 104 }
 105
 106 static void requeue_list(struct btrfs_pending_bios *pending_bios,
 107                         struct bio *head, struct bio *tail)
 108 {
 109
 110         struct bio *old_head;
 111
 112         old_head = pending_bios->head;
 113         pending_bios->head = head;
 114         if (pending_bios->tail)
 115                 tail->bi_next = old_head;
 116         else
 117                 pending_bios->tail = tail;
 118 }
 119
 120 /*
 121  * we try to collect pending bios for a device so we don't get a large
 122  * number of procs sending bios down to the same device.  This greatly
 123  * improves the schedulers ability to collect and merge the bios.
 124  *
 125  * But, it also turns into a long list of bios to process and that is sure
 126  * to eventually make the worker thread block.  The solution here is to
 127  * make some progress and then put this work struct back at the end of
 128  * the list if the block device is congested.  This way, multiple devices
 129  * can make progress from a single worker thread.
 130  */
 131 static noinline int run_scheduled_bios(struct btrfs_device *device)
 132 {
 133         struct bio *pending;
 134         struct backing_dev_info *bdi;
 135         struct btrfs_fs_info *fs_info;
 136         struct btrfs_pending_bios *pending_bios;
 137         struct bio *tail;
 138         struct bio *cur;
 139         int again = 0;
 140         unsigned long num_run;
 141         unsigned long batch_run = 0;
 142         unsigned long limit;
 143         unsigned long last_waited = 0;
 144         int force_reg = 0;
 145         int sync_pending = 0;
 146         struct blk_plug plug;
 147
 148         /*
 149          * this function runs all the bios we've collected for
 150          * a particular device.  We don't want to wander off to
 151          * another device without first sending all of these down.
 152          * So, setup a plug here and finish it off before we return
 153          */
 154         blk_start_plug(&plug);
 155
 156         bdi = blk_get_backing_dev_info(device->bdev);
 157         fs_info = device->dev_root->fs_info;
 158         limit = btrfs_async_submit_limit(fs_info);
 159         limit = limit * 2 / 3;
 160
 161 loop:
 162         spin_lock(&device->io_lock);
 163
 164 loop_lock:
 165         num_run = 0;
 166
 167         /* take all the bios off the list at once and process them
 168          * later on (without the lock held).  But, remember the
 169          * tail and other pointers so the bios can be properly reinserted
 170          * into the list if we hit congestion
 171          */
 172         if (!force_reg && device->pending_sync_bios.head) {
 173                 pending_bios = &device->pending_sync_bios;
 174                 force_reg = 1;
 175         } else {
 176                 pending_bios = &device->pending_bios;
 177                 force_reg = 0;
 178         }
 179
 180         pending = pending_bios->head;
 181         tail = pending_bios->tail;
 182         WARN_ON(pending && !tail);
 183
 184         /*
 185          * if pending was null this time around, no bios need processing
 186          * at all and we can stop.  Otherwise it'll loop back up again
 187          * and do an additional check so no bios are missed.
 188          *
 189          * device->running_pending is used to synchronize with the
 190          * schedule_bio code.
 191          */
 192         if (device->pending_sync_bios.head == NULL &&
 193             device->pending_bios.head == NULL) {
 194                 again = 0;
 195                 device->running_pending = 0;
 196         } else {
 197                 again = 1;
 198                 device->running_pending = 1;
 199         }
 200
 201         pending_bios->head = NULL;
 202         pending_bios->tail = NULL;
 203
 204         spin_unlock(&device->io_lock);
 205
 206         while (pending) {
 207
 208                 rmb();
 209                 /* we want to work on both lists, but do more bios on the
 210                  * sync list than the regular list
 211                  */
 212                 if ((num_run > 32 &&
 213                     pending_bios != &device->pending_sync_bios &&
 214                     device->pending_sync_bios.head) ||
 215                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
 216                     device->pending_bios.head)) {
 217                         spin_lock(&device->io_lock);
 218                         requeue_list(pending_bios, pending, tail);
 219                         goto loop_lock;
 220                 }
 221
 222                 cur = pending;
 223                 pending = pending->bi_next;
 224                 cur->bi_next = NULL;
 225                 atomic_dec(&fs_info->nr_async_bios);
 226
 227                 if (atomic_read(&fs_info->nr_async_bios) < limit &&
 228                     waitqueue_active(&fs_info->async_submit_wait))
 229                         wake_up(&fs_info->async_submit_wait);
 230
 231                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
 232
 233                 /*
 234                  * if we're doing the sync list, record that our
 235                  * plug has some sync requests on it
 236                  *
 237                  * If we're doing the regular list and there are
 238                  * sync requests sitting around, unplug before
 239                  * we add more
 240                  */
 241                 if (pending_bios == &device->pending_sync_bios) {
 242                         sync_pending = 1;
 243                 } else if (sync_pending) {
 244                         blk_finish_plug(&plug);
 245                         blk_start_plug(&plug);
 246                         sync_pending = 0;
 247                 }
 248
 249                 submit_bio(cur->bi_rw, cur);
 250                 num_run++;
 251                 batch_run++;
 252                 if (need_resched())
 253                         cond_resched();
 254
 255                 /*
 256                  * we made progress, there is more work to do and the bdi
 257                  * is now congested.  Back off and let other work structs
 258                  * run instead
 259                  */
 260                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
 261                     fs_info->fs_devices->open_devices > 1) {
 262                         struct io_context *ioc;
 263
 264                         ioc = current->io_context;
 265
 266                         /*
 267                          * the main goal here is that we don't want to
 268                          * block if we're going to be able to submit
 269                          * more requests without blocking.
 270                          *
 271                          * This code does two great things, it pokes into
 272                          * the elevator code from a filesystem _and_
 273                          * it makes assumptions about how batching works.
 274                          */
 275                         if (ioc && ioc->nr_batch_requests > 0 &&
 276                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
 277                             (last_waited == 0 ||
 278                              ioc->last_waited == last_waited)) {
 279                                 /*
 280                                  * we want to go through our batch of
 281                                  * requests and stop.  So, we copy out
 282                                  * the ioc->last_waited time and test
 283                                  * against it before looping
 284                                  */
 285                                 last_waited = ioc->last_waited;
 286                                 if (need_resched())
 287                                         cond_resched();
 288                                 continue;
 289                         }
 290                         spin_lock(&device->io_lock);
 291                         requeue_list(pending_bios, pending, tail);
 292                         device->running_pending = 1;
 293
 294                         spin_unlock(&device->io_lock);
 295                         btrfs_requeue_work(&device->work);
 296                         goto done;
 297                 }
 298                 /* unplug every 64 requests just for good measure */
 299                 if (batch_run % 64 == 0) {
 300                         blk_finish_plug(&plug);
 301                         blk_start_plug(&plug);
 302                         sync_pending = 0;
 303                 }
 304         }
 305
 306         cond_resched();
 307         if (again)
 308                 goto loop;
 309
 310         spin_lock(&device->io_lock);
 311         if (device->pending_bios.head || device->pending_sync_bios.head)
 312                 goto loop_lock;
 313         spin_unlock(&device->io_lock);
 314
 315 done:
 316         blk_finish_plug(&plug);
 317         return 0;
 318 }
 319
 320 static void pending_bios_fn(struct btrfs_work *work)
 321 {
 322         struct btrfs_device *device;
 323
 324         device = container_of(work, struct btrfs_device, work);
 325         run_scheduled_bios(device);
 326 }
 327
 328 static noinline int device_list_add(const char *path,
 329                            struct btrfs_super_block *disk_super,
 330                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 331 {
 332         struct btrfs_device *device;
 333         struct btrfs_fs_devices *fs_devices;
 334         u64 found_transid = btrfs_super_generation(disk_super);
 335         char *name;
 336
 337         fs_devices = find_fsid(disk_super->fsid);
 338         if (!fs_devices) {
 339                 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 340                 if (!fs_devices)
 341                         return -ENOMEM;
 342                 INIT_LIST_HEAD(&fs_devices->devices);
 343                 INIT_LIST_HEAD(&fs_devices->alloc_list);
 344                 list_add(&fs_devices->list, &fs_uuids);
 345                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
 346                 fs_devices->latest_devid = devid;
 347                 fs_devices->latest_trans = found_transid;
 348                 mutex_init(&fs_devices->device_list_mutex);
 349                 device = NULL;
 350         } else {
 351                 device = __find_device(&fs_devices->devices, devid,
 352                                        disk_super->dev_item.uuid);
 353         }
 354         if (!device) {
 355                 if (fs_devices->opened)
 356                         return -EBUSY;
 357
 358                 device = kzalloc(sizeof(*device), GFP_NOFS);
 359                 if (!device) {
 360                         /* we can safely leave the fs_devices entry around */
 361                         return -ENOMEM;
 362                 }
 363                 device->devid = devid;
 364                 device->work.func = pending_bios_fn;
 365                 memcpy(device->uuid, disk_super->dev_item.uuid,
 366                        BTRFS_UUID_SIZE);
 367                 spin_lock_init(&device->io_lock);
 368                 device->name = kstrdup(path, GFP_NOFS);
 369                 if (!device->name) {
 370                         kfree(device);
 371                         return -ENOMEM;
 372                 }
 373                 INIT_LIST_HEAD(&device->dev_alloc_list);
 374
 375                 /* init readahead state */
 376                 spin_lock_init(&device->reada_lock);
 377                 device->reada_curr_zone = NULL;
 378                 atomic_set(&device->reada_in_flight, 0);
 379                 device->reada_next = 0;
 380                 INIT_RADIX_TREE(&device->reada_zones, GFP_NOFS & ~__GFP_WAIT);
 381                 INIT_RADIX_TREE(&device->reada_extents, GFP_NOFS & ~__GFP_WAIT);
 382
 383                 mutex_lock(&fs_devices->device_list_mutex);
 384                 list_add_rcu(&device->dev_list, &fs_devices->devices);
 385                 mutex_unlock(&fs_devices->device_list_mutex);
 386
 387                 device->fs_devices = fs_devices;
 388                 fs_devices->num_devices++;
 389         } else if (!device->name || strcmp(device->name, path)) {
 390                 name = kstrdup(path, GFP_NOFS);
 391                 if (!name)
 392                         return -ENOMEM;
 393                 kfree(device->name);
 394                 device->name = name;
 395                 if (device->missing) {
 396                         fs_devices->missing_devices--;
 397                         device->missing = 0;
 398                 }
 399         }
 400
 401         if (found_transid > fs_devices->latest_trans) {
 402                 fs_devices->latest_devid = devid;
 403                 fs_devices->latest_trans = found_transid;
 404         }
 405         *fs_devices_ret = fs_devices;
 406         return 0;
 407 }
 408
 409 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
 410 {
 411         struct btrfs_fs_devices *fs_devices;
 412         struct btrfs_device *device;
 413         struct btrfs_device *orig_dev;
 414
 415         fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 416         if (!fs_devices)
 417                 return ERR_PTR(-ENOMEM);
 418
 419         INIT_LIST_HEAD(&fs_devices->devices);
 420         INIT_LIST_HEAD(&fs_devices->alloc_list);
 421         INIT_LIST_HEAD(&fs_devices->list);
 422         mutex_init(&fs_devices->device_list_mutex);
 423         fs_devices->latest_devid = orig->latest_devid;
 424         fs_devices->latest_trans = orig->latest_trans;
 425         memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
 426
 427         /* We have held the volume lock, it is safe to get the devices. */
 428         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
 429                 device = kzalloc(sizeof(*device), GFP_NOFS);
 430                 if (!device)
 431                         goto error;
 432
 433                 device->name = kstrdup(orig_dev->name, GFP_NOFS);
 434                 if (!device->name) {
 435                         kfree(device);
 436                         goto error;
 437                 }
 438
 439                 device->devid = orig_dev->devid;
 440                 device->work.func = pending_bios_fn;
 441                 memcpy(device->uuid, orig_dev->uuid, sizeof(device->uuid));
 442                 spin_lock_init(&device->io_lock);
 443                 INIT_LIST_HEAD(&device->dev_list);
 444                 INIT_LIST_HEAD(&device->dev_alloc_list);
 445
 446                 list_add(&device->dev_list, &fs_devices->devices);
 447                 device->fs_devices = fs_devices;
 448                 fs_devices->num_devices++;
 449         }
 450         return fs_devices;
 451 error:
 452         free_fs_devices(fs_devices);
 453         return ERR_PTR(-ENOMEM);
 454 }
 455
 456 int btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices)
 457 {
 458         struct btrfs_device *device, *next;
 459
 460         mutex_lock(&uuid_mutex);
 461 again:
 462         /* This is the initialized path, it is safe to release the devices. */
 463         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
 464                 if (device->in_fs_metadata)
 465                         continue;
 466
 467                 if (device->bdev) {
 468                         blkdev_put(device->bdev, device->mode);
 469                         device->bdev = NULL;
 470                         fs_devices->open_devices--;
 471                 }
 472                 if (device->writeable) {
 473                         list_del_init(&device->dev_alloc_list);
 474                         device->writeable = 0;
 475                         fs_devices->rw_devices--;
 476                 }
 477                 list_del_init(&device->dev_list);
 478                 fs_devices->num_devices--;
 479                 kfree(device->name);
 480                 kfree(device);
 481         }
 482
 483         if (fs_devices->seed) {
 484                 fs_devices = fs_devices->seed;
 485                 goto again;
 486         }
 487
 488         mutex_unlock(&uuid_mutex);
 489         return 0;
 490 }
 491
 492 static void __free_device(struct work_struct *work)
 493 {
 494         struct btrfs_device *device;
 495
 496         device = container_of(work, struct btrfs_device, rcu_work);
 497
 498         if (device->bdev)
 499                 blkdev_put(device->bdev, device->mode);
 500
 501         kfree(device->name);
 502         kfree(device);
 503 }
 504
 505 static void free_device(struct rcu_head *head)
 506 {
 507         struct btrfs_device *device;
 508
 509         device = container_of(head, struct btrfs_device, rcu);
 510
 511         INIT_WORK(&device->rcu_work, __free_device);
 512         schedule_work(&device->rcu_work);
 513 }
 514
 515 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 516 {
 517         struct btrfs_device *device;
 518
 519         if (--fs_devices->opened > 0)
 520                 return 0;
 521
 522         mutex_lock(&fs_devices->device_list_mutex);
 523         list_for_each_entry(device, &fs_devices->devices, dev_list) {
 524                 struct btrfs_device *new_device;
 525
 526                 if (device->bdev)
 527                         fs_devices->open_devices--;
 528
 529                 if (device->writeable) {
 530                         list_del_init(&device->dev_alloc_list);
 531                         fs_devices->rw_devices--;
 532                 }
 533
 534                 if (device->can_discard)
 535                         fs_devices->num_can_discard--;
 536
 537                 new_device = kmalloc(sizeof(*new_device), GFP_NOFS);
 538                 BUG_ON(!new_device);
 539                 memcpy(new_device, device, sizeof(*new_device));
 540                 new_device->name = kstrdup(device->name, GFP_NOFS);
 541                 BUG_ON(device->name && !new_device->name);
 542                 new_device->bdev = NULL;
 543                 new_device->writeable = 0;
 544                 new_device->in_fs_metadata = 0;
 545                 new_device->can_discard = 0;
 546                 list_replace_rcu(&device->dev_list, &new_device->dev_list);
 547
 548                 call_rcu(&device->rcu, free_device);
 549         }
 550         mutex_unlock(&fs_devices->device_list_mutex);
 551
 552         WARN_ON(fs_devices->open_devices);
 553         WARN_ON(fs_devices->rw_devices);
 554         fs_devices->opened = 0;
 555         fs_devices->seeding = 0;
 556
 557         return 0;
 558 }
 559
 560 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 561 {
 562         struct btrfs_fs_devices *seed_devices = NULL;
 563         int ret;
 564
 565         mutex_lock(&uuid_mutex);
 566         ret = __btrfs_close_devices(fs_devices);
 567         if (!fs_devices->opened) {
 568                 seed_devices = fs_devices->seed;
 569                 fs_devices->seed = NULL;
 570         }
 571         mutex_unlock(&uuid_mutex);
 572
 573         while (seed_devices) {
 574                 fs_devices = seed_devices;
 575                 seed_devices = fs_devices->seed;
 576                 __btrfs_close_devices(fs_devices);
 577                 free_fs_devices(fs_devices);
 578         }
 579         return ret;
 580 }
 581
 582 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 583                                 fmode_t flags, void *holder)
 584 {
 585         struct request_queue *q;
 586         struct block_device *bdev;
 587         struct list_head *head = &fs_devices->devices;
 588         struct btrfs_device *device;
 589         struct block_device *latest_bdev = NULL;
 590         struct buffer_head *bh;
 591         struct btrfs_super_block *disk_super;
 592         u64 latest_devid = 0;
 593         u64 latest_transid = 0;
 594         u64 devid;
 595         int seeding = 1;
 596         int ret = 0;
 597
 598         flags |= FMODE_EXCL;
 599
 600         list_for_each_entry(device, head, dev_list) {
 601                 if (device->bdev)
 602                         continue;
 603                 if (!device->name)
 604                         continue;
 605
 606                 bdev = blkdev_get_by_path(device->name, flags, holder);
 607                 if (IS_ERR(bdev)) {
 608                         printk(KERN_INFO "open %s failed\n", device->name);
 609                         goto error;
 610                 }
 611                 set_blocksize(bdev, 4096);
 612
 613                 bh = btrfs_read_dev_super(bdev);
 614                 if (!bh)
 615                         goto error_close;
 616
 617                 disk_super = (struct btrfs_super_block *)bh->b_data;
 618                 devid = btrfs_stack_device_id(&disk_super->dev_item);
 619                 if (devid != device->devid)
 620                         goto error_brelse;
 621
 622                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
 623                            BTRFS_UUID_SIZE))
 624                         goto error_brelse;
 625
 626                 device->generation = btrfs_super_generation(disk_super);
 627                 if (!latest_transid || device->generation > latest_transid) {
 628                         latest_devid = devid;
 629                         latest_transid = device->generation;
 630                         latest_bdev = bdev;
 631                 }
 632
 633                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
 634                         device->writeable = 0;
 635                 } else {
 636                         device->writeable = !bdev_read_only(bdev);
 637                         seeding = 0;
 638                 }
 639
 640                 q = bdev_get_queue(bdev);
 641                 if (blk_queue_discard(q)) {
 642                         device->can_discard = 1;
 643                         fs_devices->num_can_discard++;
 644                 }
 645
 646                 device->bdev = bdev;
 647                 device->in_fs_metadata = 0;
 648                 device->mode = flags;
 649
 650                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
 651                         fs_devices->rotating = 1;
 652
 653                 fs_devices->open_devices++;
 654                 if (device->writeable) {
 655                         fs_devices->rw_devices++;
 656                         list_add(&device->dev_alloc_list,
 657                                  &fs_devices->alloc_list);
 658                 }
 659                 brelse(bh);
 660                 continue;
 661
 662 error_brelse:
 663                 brelse(bh);
 664 error_close:
 665                 blkdev_put(bdev, flags);
 666 error:
 667                 continue;
 668         }
 669         if (fs_devices->open_devices == 0) {
 670                 ret = -EINVAL;
 671                 goto out;
 672         }
 673         fs_devices->seeding = seeding;
 674         fs_devices->opened = 1;
 675         fs_devices->latest_bdev = latest_bdev;
 676         fs_devices->latest_devid = latest_devid;
 677         fs_devices->latest_trans = latest_transid;
 678         fs_devices->total_rw_bytes = 0;
 679 out:
 680         return ret;
 681 }
 682
 683 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 684                        fmode_t flags, void *holder)
 685 {
 686         int ret;
 687
 688         mutex_lock(&uuid_mutex);
 689         if (fs_devices->opened) {
 690                 fs_devices->opened++;
 691                 ret = 0;
 692         } else {
 693                 ret = __btrfs_open_devices(fs_devices, flags, holder);
 694         }
 695         mutex_unlock(&uuid_mutex);
 696         return ret;
 697 }
 698
 699 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 700                           struct btrfs_fs_devices **fs_devices_ret)
 701 {
 702         struct btrfs_super_block *disk_super;
 703         struct block_device *bdev;
 704         struct buffer_head *bh;
 705         int ret;
 706         u64 devid;
 707         u64 transid;
 708
 709         mutex_lock(&uuid_mutex);
 710
 711         flags |= FMODE_EXCL;
 712         bdev = blkdev_get_by_path(path, flags, holder);
 713
 714         if (IS_ERR(bdev)) {
 715                 ret = PTR_ERR(bdev);
 716                 goto error;
 717         }
 718
 719         ret = set_blocksize(bdev, 4096);
 720         if (ret)
 721                 goto error_close;
 722         bh = btrfs_read_dev_super(bdev);
 723         if (!bh) {
 724                 ret = -EINVAL;
 725                 goto error_close;
 726         }
 727         disk_super = (struct btrfs_super_block *)bh->b_data;
 728         devid = btrfs_stack_device_id(&disk_super->dev_item);
 729         transid = btrfs_super_generation(disk_super);
 730         if (disk_super->label[0])
 731                 printk(KERN_INFO "device label %s ", disk_super->label);
 732         else
 733                 printk(KERN_INFO "device fsid %pU ", disk_super->fsid);
 734         printk(KERN_CONT "devid %llu transid %llu %s\n",
 735                (unsigned long long)devid, (unsigned long long)transid, path);
 736         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
 737
 738         brelse(bh);
 739 error_close:
 740         blkdev_put(bdev, flags);
 741 error:
 742         mutex_unlock(&uuid_mutex);
 743         return ret;
 744 }
 745
 746 /* helper to account the used device space in the range */
 747 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
 748                                    u64 end, u64 *length)
 749 {
 750         struct btrfs_key key;
 751         struct btrfs_root *root = device->dev_root;
 752         struct btrfs_dev_extent *dev_extent;
 753         struct btrfs_path *path;
 754         u64 extent_end;
 755         int ret;
 756         int slot;
 757         struct extent_buffer *l;
 758
 759         *length = 0;
 760
 761         if (start >= device->total_bytes)
 762                 return 0;
 763
 764         path = btrfs_alloc_path();
 765         if (!path)
 766                 return -ENOMEM;
 767         path->reada = 2;
 768
 769         key.objectid = device->devid;
 770         key.offset = start;
 771         key.type = BTRFS_DEV_EXTENT_KEY;
 772
 773         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 774         if (ret < 0)
 775                 goto out;
 776         if (ret > 0) {
 777                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
 778                 if (ret < 0)
 779                         goto out;
 780         }
 781
 782         while (1) {
 783                 l = path->nodes[0];
 784                 slot = path->slots[0];
 785                 if (slot >= btrfs_header_nritems(l)) {
 786                         ret = btrfs_next_leaf(root, path);
 787                         if (ret == 0)
 788                                 continue;
 789                         if (ret < 0)
 790                                 goto out;
 791
 792                         break;
 793                 }
 794                 btrfs_item_key_to_cpu(l, &key, slot);
 795
 796                 if (key.objectid < device->devid)
 797                         goto next;
 798
 799                 if (key.objectid > device->devid)
 800                         break;
 801
 802                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
 803                         goto next;
 804
 805                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
 806                 extent_end = key.offset + btrfs_dev_extent_length(l,
 807                                                                   dev_extent);
 808                 if (key.offset <= start && extent_end > end) {
 809                         *length = end - start + 1;
 810                         break;
 811                 } else if (key.offset <= start && extent_end > start)
 812                         *length += extent_end - start;
 813                 else if (key.offset > start && extent_end <= end)
 814                         *length += extent_end - key.offset;
 815                 else if (key.offset > start && key.offset <= end) {
 816                         *length += end - key.offset + 1;
 817                         break;
 818                 } else if (key.offset > end)
 819                         break;
 820
 821 next:
 822                 path->slots[0]++;
 823         }
 824         ret = 0;
 825 out:
 826         btrfs_free_path(path);
 827         return ret;
 828 }
 829
 830 /*
 831  * find_free_dev_extent - find free space in the specified device
 832  * @trans:      transaction handler
 833  * @device:     the device which we search the free space in
 834  * @num_bytes:  the size of the free space that we need
 835  * @start:      store the start of the free space.
 836  * @len:        the size of the free space. that we find, or the size of the max
 837  *              free space if we don't find suitable free space
 838  *
 839  * this uses a pretty simple search, the expectation is that it is
 840  * called very infrequently and that a given device has a small number
 841  * of extents
 842  *
 843  * @start is used to store the start of the free space if we find. But if we
 844  * don't find suitable free space, it will be used to store the start position
 845  * of the max free space.
 846  *
 847  * @len is used to store the size of the free space that we find.
 848  * But if we don't find suitable free space, it is used to store the size of
 849  * the max free space.
 850  */
 851 int find_free_dev_extent(struct btrfs_trans_handle *trans,
 852                          struct btrfs_device *device, u64 num_bytes,
 853                          u64 *start, u64 *len)
 854 {
 855         struct btrfs_key key;
 856         struct btrfs_root *root = device->dev_root;
 857         struct btrfs_dev_extent *dev_extent;
 858         struct btrfs_path *path;
 859         u64 hole_size;
 860         u64 max_hole_start;
 861         u64 max_hole_size;
 862         u64 extent_end;
 863         u64 search_start;
 864         u64 search_end = device->total_bytes;
 865         int ret;
 866         int slot;
 867         struct extent_buffer *l;
 868
 869         /* FIXME use last free of some kind */
 870
 871         /* we don't want to overwrite the superblock on the drive,
 872          * so we make sure to start at an offset of at least 1MB
 873          */
 874         search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
 875
 876         max_hole_start = search_start;
 877         max_hole_size = 0;
 878         hole_size = 0;
 879
 880         if (search_start >= search_end) {
 881                 ret = -ENOSPC;
 882                 goto error;
 883         }
 884
 885         path = btrfs_alloc_path();
 886         if (!path) {
 887                 ret = -ENOMEM;
 888                 goto error;
 889         }
 890         path->reada = 2;
 891
 892         key.objectid = device->devid;
 893         key.offset = search_start;
 894         key.type = BTRFS_DEV_EXTENT_KEY;
 895
 896         ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
 897         if (ret < 0)
 898                 goto out;
 899         if (ret > 0) {
 900                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
 901                 if (ret < 0)
 902                         goto out;
 903         }
 904
 905         while (1) {
 906                 l = path->nodes[0];
 907                 slot = path->slots[0];
 908                 if (slot >= btrfs_header_nritems(l)) {
 909                         ret = btrfs_next_leaf(root, path);
 910                         if (ret == 0)
 911                                 continue;
 912                         if (ret < 0)
 913                                 goto out;
 914
 915                         break;
 916                 }
 917                 btrfs_item_key_to_cpu(l, &key, slot);
 918
 919                 if (key.objectid < device->devid)
 920                         goto next;
 921
 922                 if (key.objectid > device->devid)
 923                         break;
 924
 925                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
 926                         goto next;
 927
 928                 if (key.offset > search_start) {
 929                         hole_size = key.offset - search_start;
 930
 931                         if (hole_size > max_hole_size) {
 932                                 max_hole_start = search_start;
 933                                 max_hole_size = hole_size;
 934                         }
 935
 936                         /*
 937                          * If this free space is greater than which we need,
 938                          * it must be the max free space that we have found
 939                          * until now, so max_hole_start must point to the start
 940                          * of this free space and the length of this free space
 941                          * is stored in max_hole_size. Thus, we return
 942                          * max_hole_start and max_hole_size and go back to the
 943                          * caller.
 944                          */
 945                         if (hole_size >= num_bytes) {
 946                                 ret = 0;
 947                                 goto out;
 948                         }
 949                 }
 950
 951                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
 952                 extent_end = key.offset + btrfs_dev_extent_length(l,
 953                                                                   dev_extent);
 954                 if (extent_end > search_start)
 955                         search_start = extent_end;
 956 next:
 957                 path->slots[0]++;
 958                 cond_resched();
 959         }
 960
 961         /*
 962          * At this point, search_start should be the end of
 963          * allocated dev extents, and when shrinking the device,
 964          * search_end may be smaller than search_start.
 965          */
 966         if (search_end > search_start)
 967                 hole_size = search_end - search_start;
 968
 969         if (hole_size > max_hole_size) {
 970                 max_hole_start = search_start;
 971                 max_hole_size = hole_size;
 972         }
 973
 974         /* See above. */
 975         if (hole_size < num_bytes)
 976                 ret = -ENOSPC;
 977         else
 978                 ret = 0;
 979
 980 out:
 981         btrfs_free_path(path);
 982 error:
 983         *start = max_hole_start;
 984         if (len)
 985                 *len = max_hole_size;
 986         return ret;
 987 }
 988
 989 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
 990                           struct btrfs_device *device,
 991                           u64 start)
 992 {
 993         int ret;
 994         struct btrfs_path *path;
 995         struct btrfs_root *root = device->dev_root;
 996         struct btrfs_key key;
 997         struct btrfs_key found_key;
 998         struct extent_buffer *leaf = NULL;
 999         struct btrfs_dev_extent *extent = NULL;
1000
1001         path = btrfs_alloc_path();
1002         if (!path)
1003                 return -ENOMEM;
1004
1005         key.objectid = device->devid;
1006         key.offset = start;
1007         key.type = BTRFS_DEV_EXTENT_KEY;
1008 again:
1009         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1010         if (ret > 0) {
1011                 ret = btrfs_previous_item(root, path, key.objectid,
1012                                           BTRFS_DEV_EXTENT_KEY);
1013                 if (ret)
1014                         goto out;
1015                 leaf = path->nodes[0];
1016                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1017                 extent = btrfs_item_ptr(leaf, path->slots[0],
1018                                         struct btrfs_dev_extent);
1019                 BUG_ON(found_key.offset > start || found_key.offset +
1020                        btrfs_dev_extent_length(leaf, extent) < start);
1021                 key = found_key;
1022                 btrfs_release_path(path);
1023                 goto again;
1024         } else if (ret == 0) {
1025                 leaf = path->nodes[0];
1026                 extent = btrfs_item_ptr(leaf, path->slots[0],
1027                                         struct btrfs_dev_extent);
1028         }
1029         BUG_ON(ret);
1030
1031         if (device->bytes_used > 0) {
1032                 u64 len = btrfs_dev_extent_length(leaf, extent);
1033                 device->bytes_used -= len;
1034                 spin_lock(&root->fs_info->free_chunk_lock);
1035                 root->fs_info->free_chunk_space += len;
1036                 spin_unlock(&root->fs_info->free_chunk_lock);
1037         }
1038         ret = btrfs_del_item(trans, root, path);
1039
1040 out:
1041         btrfs_free_path(path);
1042         return ret;
1043 }
1044
1045 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
1046                            struct btrfs_device *device,
1047                            u64 chunk_tree, u64 chunk_objectid,
1048                            u64 chunk_offset, u64 start, u64 num_bytes)
1049 {
1050         int ret;
1051         struct btrfs_path *path;
1052         struct btrfs_root *root = device->dev_root;
1053         struct btrfs_dev_extent *extent;
1054         struct extent_buffer *leaf;
1055         struct btrfs_key key;
1056
1057         WARN_ON(!device->in_fs_metadata);
1058         path = btrfs_alloc_path();
1059         if (!path)
1060                 return -ENOMEM;
1061
1062         key.objectid = device->devid;
1063         key.offset = start;
1064         key.type = BTRFS_DEV_EXTENT_KEY;
1065         ret = btrfs_insert_empty_item(trans, root, path, &key,
1066                                       sizeof(*extent));
1067         BUG_ON(ret);
1068
1069         leaf = path->nodes[0];
1070         extent = btrfs_item_ptr(leaf, path->slots[0],
1071                                 struct btrfs_dev_extent);
1072         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
1073         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
1074         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1075
1076         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
1077                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
1078                     BTRFS_UUID_SIZE);
1079
1080         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1081         btrfs_mark_buffer_dirty(leaf);
1082         btrfs_free_path(path);
1083         return ret;
1084 }
1085
1086 static noinline int find_next_chunk(struct btrfs_root *root,
1087                                     u64 objectid, u64 *offset)
1088 {
1089         struct btrfs_path *path;
1090         int ret;
1091         struct btrfs_key key;
1092         struct btrfs_chunk *chunk;
1093         struct btrfs_key found_key;
1094
1095         path = btrfs_alloc_path();
1096         if (!path)
1097                 return -ENOMEM;
1098
1099         key.objectid = objectid;
1100         key.offset = (u64)-1;
1101         key.type = BTRFS_CHUNK_ITEM_KEY;
1102
1103         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1104         if (ret < 0)
1105                 goto error;
1106
1107         BUG_ON(ret == 0);
1108
1109         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
1110         if (ret) {
1111                 *offset = 0;
1112         } else {
1113                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1114                                       path->slots[0]);
1115                 if (found_key.objectid != objectid)
1116                         *offset = 0;
1117                 else {
1118                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
1119                                                struct btrfs_chunk);
1120                         *offset = found_key.offset +
1121                                 btrfs_chunk_length(path->nodes[0], chunk);
1122                 }
1123         }
1124         ret = 0;
1125 error:
1126         btrfs_free_path(path);
1127         return ret;
1128 }
1129
1130 static noinline int find_next_devid(struct btrfs_root *root, u64 *objectid)
1131 {
1132         int ret;
1133         struct btrfs_key key;
1134         struct btrfs_key found_key;
1135         struct btrfs_path *path;
1136
1137         root = root->fs_info->chunk_root;
1138
1139         path = btrfs_alloc_path();
1140         if (!path)
1141                 return -ENOMEM;
1142
1143         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1144         key.type = BTRFS_DEV_ITEM_KEY;
1145         key.offset = (u64)-1;
1146
1147         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1148         if (ret < 0)
1149                 goto error;
1150
1151         BUG_ON(ret == 0);
1152
1153         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
1154                                   BTRFS_DEV_ITEM_KEY);
1155         if (ret) {
1156                 *objectid = 1;
1157         } else {
1158                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1159                                       path->slots[0]);
1160                 *objectid = found_key.offset + 1;
1161         }
1162         ret = 0;
1163 error:
1164         btrfs_free_path(path);
1165         return ret;
1166 }
1167
1168 /*
1169  * the device information is stored in the chunk root
1170  * the btrfs_device struct should be fully filled in
1171  */
1172 int btrfs_add_device(struct btrfs_trans_handle *trans,
1173                      struct btrfs_root *root,
1174                      struct btrfs_device *device)
1175 {
1176         int ret;
1177         struct btrfs_path *path;
1178         struct btrfs_dev_item *dev_item;
1179         struct extent_buffer *leaf;
1180         struct btrfs_key key;
1181         unsigned long ptr;
1182
1183         root = root->fs_info->chunk_root;
1184
1185         path = btrfs_alloc_path();
1186         if (!path)
1187                 return -ENOMEM;
1188
1189         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1190         key.type = BTRFS_DEV_ITEM_KEY;
1191         key.offset = device->devid;
1192
1193         ret = btrfs_insert_empty_item(trans, root, path, &key,
1194                                       sizeof(*dev_item));
1195         if (ret)
1196                 goto out;
1197
1198         leaf = path->nodes[0];
1199         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1200
1201         btrfs_set_device_id(leaf, dev_item, device->devid);
1202         btrfs_set_device_generation(leaf, dev_item, 0);
1203         btrfs_set_device_type(leaf, dev_item, device->type);
1204         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1205         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1206         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1207         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1208         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1209         btrfs_set_device_group(leaf, dev_item, 0);
1210         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1211         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1212         btrfs_set_device_start_offset(leaf, dev_item, 0);
1213
1214         ptr = (unsigned long)btrfs_device_uuid(dev_item);
1215         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1216         ptr = (unsigned long)btrfs_device_fsid(dev_item);
1217         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1218         btrfs_mark_buffer_dirty(leaf);
1219
1220         ret = 0;
1221 out:
1222         btrfs_free_path(path);
1223         return ret;
1224 }
1225
1226 static int btrfs_rm_dev_item(struct btrfs_root *root,
1227                              struct btrfs_device *device)
1228 {
1229         int ret;
1230         struct btrfs_path *path;
1231         struct btrfs_key key;
1232         struct btrfs_trans_handle *trans;
1233
1234         root = root->fs_info->chunk_root;
1235
1236         path = btrfs_alloc_path();
1237         if (!path)
1238                 return -ENOMEM;
1239
1240         trans = btrfs_start_transaction(root, 0);
1241         if (IS_ERR(trans)) {
1242                 btrfs_free_path(path);
1243                 return PTR_ERR(trans);
1244         }
1245         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1246         key.type = BTRFS_DEV_ITEM_KEY;
1247         key.offset = device->devid;
1248         lock_chunks(root);
1249
1250         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1251         if (ret < 0)
1252                 goto out;
1253
1254         if (ret > 0) {
1255                 ret = -ENOENT;
1256                 goto out;
1257         }
1258
1259         ret = btrfs_del_item(trans, root, path);
1260         if (ret)
1261                 goto out;
1262 out:
1263         btrfs_free_path(path);
1264         unlock_chunks(root);
1265         btrfs_commit_transaction(trans, root);
1266         return ret;
1267 }
1268
1269 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1270 {
1271         struct btrfs_device *device;
1272         struct btrfs_device *next_device;
1273         struct block_device *bdev;
1274         struct buffer_head *bh = NULL;
1275         struct btrfs_super_block *disk_super;
1276         struct btrfs_fs_devices *cur_devices;
1277         u64 all_avail;
1278         u64 devid;
1279         u64 num_devices;
1280         u8 *dev_uuid;
1281         int ret = 0;
1282         bool clear_super = false;
1283
1284         mutex_lock(&uuid_mutex);
1285
1286         all_avail = root->fs_info->avail_data_alloc_bits |
1287                 root->fs_info->avail_system_alloc_bits |
1288                 root->fs_info->avail_metadata_alloc_bits;
1289
1290         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) &&
1291             root->fs_info->fs_devices->num_devices <= 4) {
1292                 printk(KERN_ERR "btrfs: unable to go below four devices "
1293                        "on raid10\n");
1294                 ret = -EINVAL;
1295                 goto out;
1296         }
1297
1298         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) &&
1299             root->fs_info->fs_devices->num_devices <= 2) {
1300                 printk(KERN_ERR "btrfs: unable to go below two "
1301                        "devices on raid1\n");
1302                 ret = -EINVAL;
1303                 goto out;
1304         }
1305
1306         if (strcmp(device_path, "missing") == 0) {
1307                 struct list_head *devices;
1308                 struct btrfs_device *tmp;
1309
1310                 device = NULL;
1311                 devices = &root->fs_info->fs_devices->devices;
1312                 /*
1313                  * It is safe to read the devices since the volume_mutex
1314                  * is held.
1315                  */
1316                 list_for_each_entry(tmp, devices, dev_list) {
1317                         if (tmp->in_fs_metadata && !tmp->bdev) {
1318                                 device = tmp;
1319                                 break;
1320                         }
1321                 }
1322                 bdev = NULL;
1323                 bh = NULL;
1324                 disk_super = NULL;
1325                 if (!device) {
1326                         printk(KERN_ERR "btrfs: no missing devices found to "
1327                                "remove\n");
1328                         goto out;
1329                 }
1330         } else {
1331                 bdev = blkdev_get_by_path(device_path, FMODE_READ | FMODE_EXCL,
1332                                           root->fs_info->bdev_holder);
1333                 if (IS_ERR(bdev)) {
1334                         ret = PTR_ERR(bdev);
1335                         goto out;
1336                 }
1337
1338                 set_blocksize(bdev, 4096);
1339                 bh = btrfs_read_dev_super(bdev);
1340                 if (!bh) {
1341                         ret = -EINVAL;
1342                         goto error_close;
1343                 }
1344                 disk_super = (struct btrfs_super_block *)bh->b_data;
1345                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1346                 dev_uuid = disk_super->dev_item.uuid;
1347                 device = btrfs_find_device(root, devid, dev_uuid,
1348                                            disk_super->fsid);
1349                 if (!device) {
1350                         ret = -ENOENT;
1351                         goto error_brelse;
1352                 }
1353         }
1354
1355         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1356                 printk(KERN_ERR "btrfs: unable to remove the only writeable "
1357                        "device\n");
1358                 ret = -EINVAL;
1359                 goto error_brelse;
1360         }
1361
1362         if (device->writeable) {
1363                 lock_chunks(root);
1364                 list_del_init(&device->dev_alloc_list);
1365                 unlock_chunks(root);
1366                 root->fs_info->fs_devices->rw_devices--;
1367                 clear_super = true;
1368         }
1369
1370         ret = btrfs_shrink_device(device, 0);
1371         if (ret)
1372                 goto error_undo;
1373
1374         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1375         if (ret)
1376                 goto error_undo;
1377
1378         spin_lock(&root->fs_info->free_chunk_lock);
1379         root->fs_info->free_chunk_space = device->total_bytes -
1380                 device->bytes_used;
1381         spin_unlock(&root->fs_info->free_chunk_lock);
1382
1383         device->in_fs_metadata = 0;
1384         btrfs_scrub_cancel_dev(root, device);
1385
1386         /*
1387          * the device list mutex makes sure that we don't change
1388          * the device list while someone else is writing out all
1389          * the device supers.
1390          */
1391
1392         cur_devices = device->fs_devices;
1393         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1394         list_del_rcu(&device->dev_list);
1395
1396         device->fs_devices->num_devices--;
1397
1398         if (device->missing)
1399                 root->fs_info->fs_devices->missing_devices--;
1400
1401         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1402                                  struct btrfs_device, dev_list);
1403         if (device->bdev == root->fs_info->sb->s_bdev)
1404                 root->fs_info->sb->s_bdev = next_device->bdev;
1405         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1406                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1407
1408         if (device->bdev)
1409                 device->fs_devices->open_devices--;
1410
1411         call_rcu(&device->rcu, free_device);
1412         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1413
1414         num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
1415         btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
1416
1417         if (cur_devices->open_devices == 0) {
1418                 struct btrfs_fs_devices *fs_devices;
1419                 fs_devices = root->fs_info->fs_devices;
1420                 while (fs_devices) {
1421                         if (fs_devices->seed == cur_devices)
1422                                 break;
1423                         fs_devices = fs_devices->seed;
1424                 }
1425                 fs_devices->seed = cur_devices->seed;
1426                 cur_devices->seed = NULL;
1427                 lock_chunks(root);
1428                 __btrfs_close_devices(cur_devices);
1429                 unlock_chunks(root);
1430                 free_fs_devices(cur_devices);
1431         }
1432
1433         /*
1434          * at this point, the device is zero sized.  We want to
1435          * remove it from the devices list and zero out the old super
1436          */
1437         if (clear_super) {
1438                 /* make sure this device isn't detected as part of
1439                  * the FS anymore
1440                  */
1441                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1442                 set_buffer_dirty(bh);
1443                 sync_dirty_buffer(bh);
1444         }
1445
1446         ret = 0;
1447
1448 error_brelse:
1449         brelse(bh);
1450 error_close:
1451         if (bdev)
1452                 blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
1453 out:
1454         mutex_unlock(&uuid_mutex);
1455         return ret;
1456 error_undo:
1457         if (device->writeable) {
1458                 lock_chunks(root);
1459                 list_add(&device->dev_alloc_list,
1460                          &root->fs_info->fs_devices->alloc_list);
1461                 unlock_chunks(root);
1462                 root->fs_info->fs_devices->rw_devices++;
1463         }
1464         goto error_brelse;
1465 }
1466
1467 /*
1468  * does all the dirty work required for changing file system's UUID.
1469  */
1470 static int btrfs_prepare_sprout(struct btrfs_trans_handle *trans,
1471                                 struct btrfs_root *root)
1472 {
1473         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
1474         struct btrfs_fs_devices *old_devices;
1475         struct btrfs_fs_devices *seed_devices;
1476         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
1477         struct btrfs_device *device;
1478         u64 super_flags;
1479
1480         BUG_ON(!mutex_is_locked(&uuid_mutex));
1481         if (!fs_devices->seeding)
1482                 return -EINVAL;
1483
1484         seed_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1485         if (!seed_devices)
1486                 return -ENOMEM;
1487
1488         old_devices = clone_fs_devices(fs_devices);
1489         if (IS_ERR(old_devices)) {
1490                 kfree(seed_devices);
1491                 return PTR_ERR(old_devices);
1492         }
1493
1494         list_add(&old_devices->list, &fs_uuids);
1495
1496         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
1497         seed_devices->opened = 1;
1498         INIT_LIST_HEAD(&seed_devices->devices);
1499         INIT_LIST_HEAD(&seed_devices->alloc_list);
1500         mutex_init(&seed_devices->device_list_mutex);
1501
1502         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1503         list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
1504                               synchronize_rcu);
1505         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1506
1507         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
1508         list_for_each_entry(device, &seed_devices->devices, dev_list) {
1509                 device->fs_devices = seed_devices;
1510         }
1511
1512         fs_devices->seeding = 0;
1513         fs_devices->num_devices = 0;
1514         fs_devices->open_devices = 0;
1515         fs_devices->seed = seed_devices;
1516
1517         generate_random_uuid(fs_devices->fsid);
1518         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1519         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1520         super_flags = btrfs_super_flags(disk_super) &
1521                       ~BTRFS_SUPER_FLAG_SEEDING;
1522         btrfs_set_super_flags(disk_super, super_flags);
1523
1524         return 0;
1525 }
1526
1527 /*
1528  * strore the expected generation for seed devices in device items.
1529  */
1530 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
1531                                struct btrfs_root *root)
1532 {
1533         struct btrfs_path *path;
1534         struct extent_buffer *leaf;
1535         struct btrfs_dev_item *dev_item;
1536         struct btrfs_device *device;
1537         struct btrfs_key key;
1538         u8 fs_uuid[BTRFS_UUID_SIZE];
1539         u8 dev_uuid[BTRFS_UUID_SIZE];
1540         u64 devid;
1541         int ret;
1542
1543         path = btrfs_alloc_path();
1544         if (!path)
1545                 return -ENOMEM;
1546
1547         root = root->fs_info->chunk_root;
1548         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1549         key.offset = 0;
1550         key.type = BTRFS_DEV_ITEM_KEY;
1551
1552         while (1) {
1553                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1554                 if (ret < 0)
1555                         goto error;
1556
1557                 leaf = path->nodes[0];
1558 next_slot:
1559                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1560                         ret = btrfs_next_leaf(root, path);
1561                         if (ret > 0)
1562                                 break;
1563                         if (ret < 0)
1564                                 goto error;
1565                         leaf = path->nodes[0];
1566                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1567                         btrfs_release_path(path);
1568                         continue;
1569                 }
1570
1571                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1572                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
1573                     key.type != BTRFS_DEV_ITEM_KEY)
1574                         break;
1575
1576                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
1577                                           struct btrfs_dev_item);
1578                 devid = btrfs_device_id(leaf, dev_item);
1579                 read_extent_buffer(leaf, dev_uuid,
1580                                    (unsigned long)btrfs_device_uuid(dev_item),
1581                                    BTRFS_UUID_SIZE);
1582                 read_extent_buffer(leaf, fs_uuid,
1583                                    (unsigned long)btrfs_device_fsid(dev_item),
1584                                    BTRFS_UUID_SIZE);
1585                 device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
1586                 BUG_ON(!device);
1587
1588                 if (device->fs_devices->seeding) {
1589                         btrfs_set_device_generation(leaf, dev_item,
1590                                                     device->generation);
1591                         btrfs_mark_buffer_dirty(leaf);
1592                 }
1593
1594                 path->slots[0]++;
1595                 goto next_slot;
1596         }
1597         ret = 0;
1598 error:
1599         btrfs_free_path(path);
1600         return ret;
1601 }
1602
1603 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
1604 {
1605         struct request_queue *q;
1606         struct btrfs_trans_handle *trans;
1607         struct btrfs_device *device;
1608         struct block_device *bdev;
1609         struct list_head *devices;
1610         struct super_block *sb = root->fs_info->sb;
1611         u64 total_bytes;
1612         int seeding_dev = 0;
1613         int ret = 0;
1614
1615         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
1616                 return -EINVAL;
1617
1618         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
1619                                   root->fs_info->bdev_holder);
1620         if (IS_ERR(bdev))
1621                 return PTR_ERR(bdev);
1622
1623         if (root->fs_info->fs_devices->seeding) {
1624                 seeding_dev = 1;
1625                 down_write(&sb->s_umount);
1626                 mutex_lock(&uuid_mutex);
1627         }
1628
1629         filemap_write_and_wait(bdev->bd_inode->i_mapping);
1630
1631         devices = &root->fs_info->fs_devices->devices;
1632         /*
1633          * we have the volume lock, so we don't need the extra
1634          * device list mutex while reading the list here.
1635          */
1636         list_for_each_entry(device, devices, dev_list) {
1637                 if (device->bdev == bdev) {
1638                         ret = -EEXIST;
1639                         goto error;
1640                 }
1641         }
1642
1643         device = kzalloc(sizeof(*device), GFP_NOFS);
1644         if (!device) {
1645                 /* we can safely leave the fs_devices entry around */
1646                 ret = -ENOMEM;
1647                 goto error;
1648         }
1649
1650         device->name = kstrdup(device_path, GFP_NOFS);
1651         if (!device->name) {
1652                 kfree(device);
1653                 ret = -ENOMEM;
1654                 goto error;
1655         }
1656
1657         ret = find_next_devid(root, &device->devid);
1658         if (ret) {
1659                 kfree(device->name);
1660                 kfree(device);
1661                 goto error;
1662         }
1663
1664         trans = btrfs_start_transaction(root, 0);
1665         if (IS_ERR(trans)) {
1666                 kfree(device->name);
1667                 kfree(device);
1668                 ret = PTR_ERR(trans);
1669                 goto error;
1670         }
1671
1672         lock_chunks(root);
1673
1674         q = bdev_get_queue(bdev);
1675         if (blk_queue_discard(q))
1676                 device->can_discard = 1;
1677         device->writeable = 1;
1678         device->work.func = pending_bios_fn;
1679         generate_random_uuid(device->uuid);
1680         spin_lock_init(&device->io_lock);
1681         device->generation = trans->transid;
1682         device->io_width = root->sectorsize;
1683         device->io_align = root->sectorsize;
1684         device->sector_size = root->sectorsize;
1685         device->total_bytes = i_size_read(bdev->bd_inode);
1686         device->disk_total_bytes = device->total_bytes;
1687         device->dev_root = root->fs_info->dev_root;
1688         device->bdev = bdev;
1689         device->in_fs_metadata = 1;
1690         device->mode = FMODE_EXCL;
1691         set_blocksize(device->bdev, 4096);
1692
1693         if (seeding_dev) {
1694                 sb->s_flags &= ~MS_RDONLY;
1695                 ret = btrfs_prepare_sprout(trans, root);
1696                 BUG_ON(ret);
1697         }
1698
1699         device->fs_devices = root->fs_info->fs_devices;
1700
1701         /*
1702          * we don't want write_supers to jump in here with our device
1703          * half setup
1704          */
1705         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1706         list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
1707         list_add(&device->dev_alloc_list,
1708                  &root->fs_info->fs_devices->alloc_list);
1709         root->fs_info->fs_devices->num_devices++;
1710         root->fs_info->fs_devices->open_devices++;
1711         root->fs_info->fs_devices->rw_devices++;
1712         if (device->can_discard)
1713                 root->fs_info->fs_devices->num_can_discard++;
1714         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
1715
1716         spin_lock(&root->fs_info->free_chunk_lock);
1717         root->fs_info->free_chunk_space += device->total_bytes;
1718         spin_unlock(&root->fs_info->free_chunk_lock);
1719
1720         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
1721                 root->fs_info->fs_devices->rotating = 1;
1722
1723         total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
1724         btrfs_set_super_total_bytes(root->fs_info->super_copy,
1725                                     total_bytes + device->total_bytes);
1726
1727         total_bytes = btrfs_super_num_devices(root->fs_info->super_copy);
1728         btrfs_set_super_num_devices(root->fs_info->super_copy,
1729                                     total_bytes + 1);
1730         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1731
1732         if (seeding_dev) {
1733                 ret = init_first_rw_device(trans, root, device);
1734                 BUG_ON(ret);
1735                 ret = btrfs_finish_sprout(trans, root);
1736                 BUG_ON(ret);
1737         } else {
1738                 ret = btrfs_add_device(trans, root, device);
1739         }
1740
1741         /*
1742          * we've got more storage, clear any full flags on the space
1743          * infos
1744          */
1745         btrfs_clear_space_info_full(root->fs_info);
1746
1747         unlock_chunks(root);
1748         btrfs_commit_transaction(trans, root);
1749
1750         if (seeding_dev) {
1751                 mutex_unlock(&uuid_mutex);
1752                 up_write(&sb->s_umount);
1753
1754                 ret = btrfs_relocate_sys_chunks(root);
1755                 BUG_ON(ret);
1756         }
1757
1758         return ret;
1759 error:
1760         blkdev_put(bdev, FMODE_EXCL);
1761         if (seeding_dev) {
1762                 mutex_unlock(&uuid_mutex);
1763                 up_write(&sb->s_umount);
1764         }
1765         return ret;
1766 }
1767
1768 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
1769                                         struct btrfs_device *device)
1770 {
1771         int ret;
1772         struct btrfs_path *path;
1773         struct btrfs_root *root;
1774         struct btrfs_dev_item *dev_item;
1775         struct extent_buffer *leaf;
1776         struct btrfs_key key;
1777
1778         root = device->dev_root->fs_info->chunk_root;
1779
1780         path = btrfs_alloc_path();
1781         if (!path)
1782                 return -ENOMEM;
1783
1784         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1785         key.type = BTRFS_DEV_ITEM_KEY;
1786         key.offset = device->devid;
1787
1788         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1789         if (ret < 0)
1790                 goto out;
1791
1792         if (ret > 0) {
1793                 ret = -ENOENT;
1794                 goto out;
1795         }
1796
1797         leaf = path->nodes[0];
1798         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1799
1800         btrfs_set_device_id(leaf, dev_item, device->devid);
1801         btrfs_set_device_type(leaf, dev_item, device->type);
1802         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1803         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1804         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1805         btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
1806         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1807         btrfs_mark_buffer_dirty(leaf);
1808
1809 out:
1810         btrfs_free_path(path);
1811         return ret;
1812 }
1813
1814 static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
1815                       struct btrfs_device *device, u64 new_size)
1816 {
1817         struct btrfs_super_block *super_copy =
1818                 device->dev_root->fs_info->super_copy;
1819         u64 old_total = btrfs_super_total_bytes(super_copy);
1820         u64 diff = new_size - device->total_bytes;
1821
1822         if (!device->writeable)
1823                 return -EACCES;
1824         if (new_size <= device->total_bytes)
1825                 return -EINVAL;
1826
1827         btrfs_set_super_total_bytes(super_copy, old_total + diff);
1828         device->fs_devices->total_rw_bytes += diff;
1829
1830         device->total_bytes = new_size;
1831         device->disk_total_bytes = new_size;
1832         btrfs_clear_space_info_full(device->dev_root->fs_info);
1833
1834         return btrfs_update_device(trans, device);
1835 }
1836
1837 int btrfs_grow_device(struct btrfs_trans_handle *trans,
1838                       struct btrfs_device *device, u64 new_size)
1839 {
1840         int ret;
1841         lock_chunks(device->dev_root);
1842         ret = __btrfs_grow_device(trans, device, new_size);
1843         unlock_chunks(device->dev_root);
1844         return ret;
1845 }
1846
1847 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
1848                             struct btrfs_root *root,
1849                             u64 chunk_tree, u64 chunk_objectid,
1850                             u64 chunk_offset)
1851 {
1852         int ret;
1853         struct btrfs_path *path;
1854         struct btrfs_key key;
1855
1856         root = root->fs_info->chunk_root;
1857         path = btrfs_alloc_path();
1858         if (!path)
1859                 return -ENOMEM;
1860
1861         key.objectid = chunk_objectid;
1862         key.offset = chunk_offset;
1863         key.type = BTRFS_CHUNK_ITEM_KEY;
1864
1865         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1866         BUG_ON(ret);
1867
1868         ret = btrfs_del_item(trans, root, path);
1869
1870         btrfs_free_path(path);
1871         return ret;
1872 }
1873
1874 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
1875                         chunk_offset)
1876 {
1877         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
1878         struct btrfs_disk_key *disk_key;
1879         struct btrfs_chunk *chunk;
1880         u8 *ptr;
1881         int ret = 0;
1882         u32 num_stripes;
1883         u32 array_size;
1884         u32 len = 0;
1885         u32 cur;
1886         struct btrfs_key key;
1887
1888         array_size = btrfs_super_sys_array_size(super_copy);
1889
1890         ptr = super_copy->sys_chunk_array;
1891         cur = 0;
1892
1893         while (cur < array_size) {
1894                 disk_key = (struct btrfs_disk_key *)ptr;
1895                 btrfs_disk_key_to_cpu(&key, disk_key);
1896
1897                 len = sizeof(*disk_key);
1898
1899                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
1900                         chunk = (struct btrfs_chunk *)(ptr + len);
1901                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
1902                         len += btrfs_chunk_item_size(num_stripes);
1903                 } else {
1904                         ret = -EIO;
1905                         break;
1906                 }
1907                 if (key.objectid == chunk_objectid &&
1908                     key.offset == chunk_offset) {
1909                         memmove(ptr, ptr + len, array_size - (cur + len));
1910                         array_size -= len;
1911                         btrfs_set_super_sys_array_size(super_copy, array_size);
1912                 } else {
1913                         ptr += len;
1914                         cur += len;
1915                 }
1916         }
1917         return ret;
1918 }
1919
1920 static int btrfs_relocate_chunk(struct btrfs_root *root,
1921                          u64 chunk_tree, u64 chunk_objectid,
1922                          u64 chunk_offset)
1923 {
1924         struct extent_map_tree *em_tree;
1925         struct btrfs_root *extent_root;
1926         struct btrfs_trans_handle *trans;
1927         struct extent_map *em;
1928         struct map_lookup *map;
1929         int ret;
1930         int i;
1931
1932         root = root->fs_info->chunk_root;
1933         extent_root = root->fs_info->extent_root;
1934         em_tree = &root->fs_info->mapping_tree.map_tree;
1935
1936         ret = btrfs_can_relocate(extent_root, chunk_offset);
1937         if (ret)
1938                 return -ENOSPC;
1939
1940         /* step one, relocate all the extents inside this chunk */
1941         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
1942         if (ret)
1943                 return ret;
1944
1945         trans = btrfs_start_transaction(root, 0);
1946         BUG_ON(IS_ERR(trans));
1947
1948         lock_chunks(root);
1949
1950         /*
1951          * step two, delete the device extents and the
1952          * chunk tree entries
1953          */
1954         read_lock(&em_tree->lock);
1955         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
1956         read_unlock(&em_tree->lock);
1957
1958         BUG_ON(em->start > chunk_offset ||
1959                em->start + em->len < chunk_offset);
1960         map = (struct map_lookup *)em->bdev;
1961
1962         for (i = 0; i < map->num_stripes; i++) {
1963                 ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
1964                                             map->stripes[i].physical);
1965                 BUG_ON(ret);
1966
1967                 if (map->stripes[i].dev) {
1968                         ret = btrfs_update_device(trans, map->stripes[i].dev);
1969                         BUG_ON(ret);
1970                 }
1971         }
1972         ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
1973                                chunk_offset);
1974
1975         BUG_ON(ret);
1976
1977         trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
1978
1979         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
1980                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
1981                 BUG_ON(ret);
1982         }
1983
1984         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
1985         BUG_ON(ret);
1986
1987         write_lock(&em_tree->lock);
1988         remove_extent_mapping(em_tree, em);
1989         write_unlock(&em_tree->lock);
1990
1991         kfree(map);
1992         em->bdev = NULL;
1993
1994         /* once for the tree */
1995         free_extent_map(em);
1996         /* once for us */
1997         free_extent_map(em);
1998
1999         unlock_chunks(root);
2000         btrfs_end_transaction(trans, root);
2001         return 0;
2002 }
2003
2004 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
2005 {
2006         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
2007         struct btrfs_path *path;
2008         struct extent_buffer *leaf;
2009         struct btrfs_chunk *chunk;
2010         struct btrfs_key key;
2011         struct btrfs_key found_key;
2012         u64 chunk_tree = chunk_root->root_key.objectid;
2013         u64 chunk_type;
2014         bool retried = false;
2015         int failed = 0;
2016         int ret;
2017
2018         path = btrfs_alloc_path();
2019         if (!path)
2020                 return -ENOMEM;
2021
2022 again:
2023         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2024         key.offset = (u64)-1;
2025         key.type = BTRFS_CHUNK_ITEM_KEY;
2026
2027         while (1) {
2028                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2029                 if (ret < 0)
2030                         goto error;
2031                 BUG_ON(ret == 0);
2032
2033                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
2034                                           key.type);
2035                 if (ret < 0)
2036                         goto error;
2037                 if (ret > 0)
2038                         break;
2039
2040                 leaf = path->nodes[0];
2041                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2042
2043                 chunk = btrfs_item_ptr(leaf, path->slots[0],
2044                                        struct btrfs_chunk);
2045                 chunk_type = btrfs_chunk_type(leaf, chunk);
2046                 btrfs_release_path(path);
2047
2048                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
2049                         ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
2050                                                    found_key.objectid,
2051                                                    found_key.offset);
2052                         if (ret == -ENOSPC)
2053                                 failed++;
2054                         else if (ret)
2055                                 BUG();
2056                 }
2057
2058                 if (found_key.offset == 0)
2059                         break;
2060                 key.offset = found_key.offset - 1;
2061         }
2062         ret = 0;
2063         if (failed && !retried) {
2064                 failed = 0;
2065                 retried = true;
2066                 goto again;
2067         } else if (failed && retried) {
2068                 WARN_ON(1);
2069                 ret = -ENOSPC;
2070         }
2071 error:
2072         btrfs_free_path(path);
2073         return ret;
2074 }
2075
2076 /*
2077  * Should be called with both balance and volume mutexes held to
2078  * serialize other volume operations (add_dev/rm_dev/resize) with
2079  * restriper.  Same goes for unset_balance_control.
2080  */
2081 static void set_balance_control(struct btrfs_balance_control *bctl)
2082 {
2083         struct btrfs_fs_info *fs_info = bctl->fs_info;
2084
2085         BUG_ON(fs_info->balance_ctl);
2086
2087         spin_lock(&fs_info->balance_lock);
2088         fs_info->balance_ctl = bctl;
2089         spin_unlock(&fs_info->balance_lock);
2090 }
2091
2092 static void unset_balance_control(struct btrfs_fs_info *fs_info)
2093 {
2094         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2095
2096         BUG_ON(!fs_info->balance_ctl);
2097
2098         spin_lock(&fs_info->balance_lock);
2099         fs_info->balance_ctl = NULL;
2100         spin_unlock(&fs_info->balance_lock);
2101
2102         kfree(bctl);
2103 }
2104
2105 /*
2106  * Balance filters.  Return 1 if chunk should be filtered out
2107  * (should not be balanced).
2108  */
2109 static int chunk_profiles_filter(u64 chunk_profile,
2110                                  struct btrfs_balance_args *bargs)
2111 {
2112         chunk_profile &= BTRFS_BLOCK_GROUP_PROFILE_MASK;
2113
2114         if (chunk_profile == 0)
2115                 chunk_profile = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
2116
2117         if (bargs->profiles & chunk_profile)
2118                 return 0;
2119
2120         return 1;
2121 }
2122
2123 static u64 div_factor_fine(u64 num, int factor)
2124 {
2125         if (factor <= 0)
2126                 return 0;
2127         if (factor >= 100)
2128                 return num;
2129
2130         num *= factor;
2131         do_div(num, 100);
2132         return num;
2133 }
2134
2135 static int chunk_usage_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
2136                               struct btrfs_balance_args *bargs)
2137 {
2138         struct btrfs_block_group_cache *cache;
2139         u64 chunk_used, user_thresh;
2140         int ret = 1;
2141
2142         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
2143         chunk_used = btrfs_block_group_used(&cache->item);
2144
2145         user_thresh = div_factor_fine(cache->key.offset, bargs->usage);
2146         if (chunk_used < user_thresh)
2147                 ret = 0;
2148
2149         btrfs_put_block_group(cache);
2150         return ret;
2151 }
2152
2153 static int should_balance_chunk(struct btrfs_root *root,
2154                                 struct extent_buffer *leaf,
2155                                 struct btrfs_chunk *chunk, u64 chunk_offset)
2156 {
2157         struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
2158         struct btrfs_balance_args *bargs = NULL;
2159         u64 chunk_type = btrfs_chunk_type(leaf, chunk);
2160
2161         /* type filter */
2162         if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
2163               (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
2164                 return 0;
2165         }
2166
2167         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
2168                 bargs = &bctl->data;
2169         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
2170                 bargs = &bctl->sys;
2171         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
2172                 bargs = &bctl->meta;
2173
2174         /* profiles filter */
2175         if ((bargs->flags & BTRFS_BALANCE_ARGS_PROFILES) &&
2176             chunk_profiles_filter(chunk_type, bargs)) {
2177                 return 0;
2178         }
2179
2180         /* usage filter */
2181         if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
2182             chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
2183                 return 0;
2184         }
2185
2186         return 1;
2187 }
2188
2189 static u64 div_factor(u64 num, int factor)
2190 {
2191         if (factor == 10)
2192                 return num;
2193         num *= factor;
2194         do_div(num, 10);
2195         return num;
2196 }
2197
2198 static int __btrfs_balance(struct btrfs_fs_info *fs_info)
2199 {
2200         struct btrfs_root *chunk_root = fs_info->chunk_root;
2201         struct btrfs_root *dev_root = fs_info->dev_root;
2202         struct list_head *devices;
2203         struct btrfs_device *device;
2204         u64 old_size;
2205         u64 size_to_free;
2206         struct btrfs_chunk *chunk;
2207         struct btrfs_path *path;
2208         struct btrfs_key key;
2209         struct btrfs_key found_key;
2210         struct btrfs_trans_handle *trans;
2211         struct extent_buffer *leaf;
2212         int slot;
2213         int ret;
2214         int enospc_errors = 0;
2215
2216         /* step one make some room on all the devices */
2217         devices = &fs_info->fs_devices->devices;
2218         list_for_each_entry(device, devices, dev_list) {
2219                 old_size = device->total_bytes;
2220                 size_to_free = div_factor(old_size, 1);
2221                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
2222                 if (!device->writeable ||
2223                     device->total_bytes - device->bytes_used > size_to_free)
2224                         continue;
2225
2226                 ret = btrfs_shrink_device(device, old_size - size_to_free);
2227                 if (ret == -ENOSPC)
2228                         break;
2229                 BUG_ON(ret);
2230
2231                 trans = btrfs_start_transaction(dev_root, 0);
2232                 BUG_ON(IS_ERR(trans));
2233
2234                 ret = btrfs_grow_device(trans, device, old_size);
2235                 BUG_ON(ret);
2236
2237                 btrfs_end_transaction(trans, dev_root);
2238         }
2239
2240         /* step two, relocate all the chunks */
2241         path = btrfs_alloc_path();
2242         if (!path) {
2243                 ret = -ENOMEM;
2244                 goto error;
2245         }
2246         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2247         key.offset = (u64)-1;
2248         key.type = BTRFS_CHUNK_ITEM_KEY;
2249
2250         while (1) {
2251                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2252                 if (ret < 0)
2253                         goto error;
2254
2255                 /*
2256                  * this shouldn't happen, it means the last relocate
2257                  * failed
2258                  */
2259                 if (ret == 0)
2260                         BUG(); /* FIXME break ? */
2261
2262                 ret = btrfs_previous_item(chunk_root, path, 0,
2263                                           BTRFS_CHUNK_ITEM_KEY);
2264                 if (ret) {
2265                         ret = 0;
2266                         break;
2267                 }
2268
2269                 leaf = path->nodes[0];
2270                 slot = path->slots[0];
2271                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2272
2273                 if (found_key.objectid != key.objectid)
2274                         break;
2275
2276                 /* chunk zero is special */
2277                 if (found_key.offset == 0)
2278                         break;
2279
2280                 chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
2281
2282                 ret = should_balance_chunk(chunk_root, leaf, chunk,
2283                                            found_key.offset);
2284                 btrfs_release_path(path);
2285                 if (!ret)
2286                         goto loop;
2287
2288                 ret = btrfs_relocate_chunk(chunk_root,
2289                                            chunk_root->root_key.objectid,
2290                                            found_key.objectid,
2291                                            found_key.offset);
2292                 if (ret && ret != -ENOSPC)
2293                         goto error;
2294                 if (ret == -ENOSPC)
2295                         enospc_errors++;
2296 loop:
2297                 key.offset = found_key.offset - 1;
2298         }
2299
2300 error:
2301         btrfs_free_path(path);
2302         if (enospc_errors) {
2303                 printk(KERN_INFO "btrfs: %d enospc errors during balance\n",
2304                        enospc_errors);
2305                 if (!ret)
2306                         ret = -ENOSPC;
2307         }
2308
2309         return ret;
2310 }
2311
2312 static void __cancel_balance(struct btrfs_fs_info *fs_info)
2313 {
2314         unset_balance_control(fs_info);
2315 }
2316
2317 void update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
2318                                struct btrfs_ioctl_balance_args *bargs);
2319
2320 /*
2321  * Should be called with both balance and volume mutexes held
2322  */
2323 int btrfs_balance(struct btrfs_balance_control *bctl,
2324                   struct btrfs_ioctl_balance_args *bargs)
2325 {
2326         struct btrfs_fs_info *fs_info = bctl->fs_info;
2327         u64 allowed;
2328         int ret;
2329
2330         if (btrfs_fs_closing(fs_info)) {
2331                 ret = -EINVAL;
2332                 goto out;
2333         }
2334
2335         /*
2336          * In case of mixed groups both data and meta should be picked,
2337          * and identical options should be given for both of them.
2338          */
2339         allowed = btrfs_super_incompat_flags(fs_info->super_copy);
2340         if ((allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS) &&
2341             (bctl->flags & (BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA))) {
2342                 if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
2343                     !(bctl->flags & BTRFS_BALANCE_METADATA) ||
2344                     memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
2345                         printk(KERN_ERR "btrfs: with mixed groups data and "
2346                                "metadata balance options must be the same\n");
2347                         ret = -EINVAL;
2348                         goto out;
2349                 }
2350         }
2351
2352         set_balance_control(bctl);
2353
2354         mutex_unlock(&fs_info->balance_mutex);
2355
2356         ret = __btrfs_balance(fs_info);
2357
2358         mutex_lock(&fs_info->balance_mutex);
2359
2360         if (bargs) {
2361                 memset(bargs, 0, sizeof(*bargs));
2362                 update_ioctl_balance_args(fs_info, bargs);
2363         }
2364
2365         __cancel_balance(fs_info);
2366
2367         return ret;
2368 out:
2369         kfree(bctl);
2370         return ret;
2371 }
2372
2373 /*
2374  * shrinking a device means finding all of the device extents past
2375  * the new size, and then following the back refs to the chunks.
2376  * The chunk relocation code actually frees the device extent
2377  */
2378 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
2379 {
2380         struct btrfs_trans_handle *trans;
2381         struct btrfs_root *root = device->dev_root;
2382         struct btrfs_dev_extent *dev_extent = NULL;
2383         struct btrfs_path *path;
2384         u64 length;
2385         u64 chunk_tree;
2386         u64 chunk_objectid;
2387         u64 chunk_offset;
2388         int ret;
2389         int slot;
2390         int failed = 0;
2391         bool retried = false;
2392         struct extent_buffer *l;
2393         struct btrfs_key key;
2394         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
2395         u64 old_total = btrfs_super_total_bytes(super_copy);
2396         u64 old_size = device->total_bytes;
2397         u64 diff = device->total_bytes - new_size;
2398
2399         if (new_size >= device->total_bytes)
2400                 return -EINVAL;
2401
2402         path = btrfs_alloc_path();
2403         if (!path)
2404                 return -ENOMEM;
2405
2406         path->reada = 2;
2407
2408         lock_chunks(root);
2409
2410         device->total_bytes = new_size;
2411         if (device->writeable) {
2412                 device->fs_devices->total_rw_bytes -= diff;
2413                 spin_lock(&root->fs_info->free_chunk_lock);
2414                 root->fs_info->free_chunk_space -= diff;
2415                 spin_unlock(&root->fs_info->free_chunk_lock);
2416         }
2417         unlock_chunks(root);
2418
2419 again:
2420         key.objectid = device->devid;
2421         key.offset = (u64)-1;
2422         key.type = BTRFS_DEV_EXTENT_KEY;
2423
2424         while (1) {
2425                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2426                 if (ret < 0)
2427                         goto done;
2428
2429                 ret = btrfs_previous_item(root, path, 0, key.type);
2430                 if (ret < 0)
2431                         goto done;
2432                 if (ret) {
2433                         ret = 0;
2434                         btrfs_release_path(path);
2435                         break;
2436                 }
2437
2438                 l = path->nodes[0];
2439                 slot = path->slots[0];
2440                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
2441
2442                 if (key.objectid != device->devid) {
2443                         btrfs_release_path(path);
2444                         break;
2445                 }
2446
2447                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
2448                 length = btrfs_dev_extent_length(l, dev_extent);
2449
2450                 if (key.offset + length <= new_size) {
2451                         btrfs_release_path(path);
2452                         break;
2453                 }
2454
2455                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
2456                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
2457                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
2458                 btrfs_release_path(path);
2459
2460                 ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
2461                                            chunk_offset);
2462                 if (ret && ret != -ENOSPC)
2463                         goto done;
2464                 if (ret == -ENOSPC)
2465                         failed++;
2466                 key.offset -= 1;
2467         }
2468
2469         if (failed && !retried) {
2470                 failed = 0;
2471                 retried = true;
2472                 goto again;
2473         } else if (failed && retried) {
2474                 ret = -ENOSPC;
2475                 lock_chunks(root);
2476
2477                 device->total_bytes = old_size;
2478                 if (device->writeable)
2479                         device->fs_devices->total_rw_bytes += diff;
2480                 spin_lock(&root->fs_info->free_chunk_lock);
2481                 root->fs_info->free_chunk_space += diff;
2482                 spin_unlock(&root->fs_info->free_chunk_lock);
2483                 unlock_chunks(root);
2484                 goto done;
2485         }
2486
2487         /* Shrinking succeeded, else we would be at "done". */
2488         trans = btrfs_start_transaction(root, 0);
2489         if (IS_ERR(trans)) {
2490                 ret = PTR_ERR(trans);
2491                 goto done;
2492         }
2493
2494         lock_chunks(root);
2495
2496         device->disk_total_bytes = new_size;
2497         /* Now btrfs_update_device() will change the on-disk size. */
2498         ret = btrfs_update_device(trans, device);
2499         if (ret) {
2500                 unlock_chunks(root);
2501                 btrfs_end_transaction(trans, root);
2502                 goto done;
2503         }
2504         WARN_ON(diff > old_total);
2505         btrfs_set_super_total_bytes(super_copy, old_total - diff);
2506         unlock_chunks(root);
2507         btrfs_end_transaction(trans, root);
2508 done:
2509         btrfs_free_path(path);
2510         return ret;
2511 }
2512
2513 static int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
2514                            struct btrfs_root *root,
2515                            struct btrfs_key *key,
2516                            struct btrfs_chunk *chunk, int item_size)
2517 {
2518         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
2519         struct btrfs_disk_key disk_key;
2520         u32 array_size;
2521         u8 *ptr;
2522
2523         array_size = btrfs_super_sys_array_size(super_copy);
2524         if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
2525                 return -EFBIG;
2526
2527         ptr = super_copy->sys_chunk_array + array_size;
2528         btrfs_cpu_key_to_disk(&disk_key, key);
2529         memcpy(ptr, &disk_key, sizeof(disk_key));
2530         ptr += sizeof(disk_key);
2531         memcpy(ptr, chunk, item_size);
2532         item_size += sizeof(disk_key);
2533         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
2534         return 0;
2535 }
2536
2537 /*
2538  * sort the devices in descending order by max_avail, total_avail
2539  */
2540 static int btrfs_cmp_device_info(const void *a, const void *b)
2541 {
2542         const struct btrfs_device_info *di_a = a;
2543         const struct btrfs_device_info *di_b = b;
2544
2545         if (di_a->max_avail > di_b->max_avail)
2546                 return -1;
2547         if (di_a->max_avail < di_b->max_avail)
2548                 return 1;
2549         if (di_a->total_avail > di_b->total_avail)
2550                 return -1;
2551         if (di_a->total_avail < di_b->total_avail)
2552                 return 1;
2553         return 0;
2554 }
2555
2556 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
2557                                struct btrfs_root *extent_root,
2558                                struct map_lookup **map_ret,
2559                                u64 *num_bytes_out, u64 *stripe_size_out,
2560                                u64 start, u64 type)
2561 {
2562         struct btrfs_fs_info *info = extent_root->fs_info;
2563         struct btrfs_fs_devices *fs_devices = info->fs_devices;
2564         struct list_head *cur;
2565         struct map_lookup *map = NULL;
2566         struct extent_map_tree *em_tree;
2567         struct extent_map *em;
2568         struct btrfs_device_info *devices_info = NULL;
2569         u64 total_avail;
2570         int num_stripes;        /* total number of stripes to allocate */
2571         int sub_stripes;        /* sub_stripes info for map */
2572         int dev_stripes;        /* stripes per dev */
2573         int devs_max;           /* max devs to use */
2574         int devs_min;           /* min devs needed */
2575         int devs_increment;     /* ndevs has to be a multiple of this */
2576         int ncopies;            /* how many copies to data has */
2577         int ret;
2578         u64 max_stripe_size;
2579         u64 max_chunk_size;
2580         u64 stripe_size;
2581         u64 num_bytes;
2582         int ndevs;
2583         int i;
2584         int j;
2585
2586         if ((type & BTRFS_BLOCK_GROUP_RAID1) &&
2587             (type & BTRFS_BLOCK_GROUP_DUP)) {
2588                 WARN_ON(1);
2589                 type &= ~BTRFS_BLOCK_GROUP_DUP;
2590         }
2591
2592         if (list_empty(&fs_devices->alloc_list))
2593                 return -ENOSPC;
2594
2595         sub_stripes = 1;
2596         dev_stripes = 1;
2597         devs_increment = 1;
2598         ncopies = 1;
2599         devs_max = 0;   /* 0 == as many as possible */
2600         devs_min = 1;
2601
2602         /*
2603          * define the properties of each RAID type.
2604          * FIXME: move this to a global table and use it in all RAID
2605          * calculation code
2606          */
2607         if (type & (BTRFS_BLOCK_GROUP_DUP)) {
2608                 dev_stripes = 2;
2609                 ncopies = 2;
2610                 devs_max = 1;
2611         } else if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
2612                 devs_min = 2;
2613         } else if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
2614                 devs_increment = 2;
2615                 ncopies = 2;
2616                 devs_max = 2;
2617                 devs_min = 2;
2618         } else if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
2619                 sub_stripes = 2;
2620                 devs_increment = 2;
2621                 ncopies = 2;
2622                 devs_min = 4;
2623         } else {
2624                 devs_max = 1;
2625         }
2626
2627         if (type & BTRFS_BLOCK_GROUP_DATA) {
2628                 max_stripe_size = 1024 * 1024 * 1024;
2629                 max_chunk_size = 10 * max_stripe_size;
2630         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
2631                 max_stripe_size = 256 * 1024 * 1024;
2632                 max_chunk_size = max_stripe_size;
2633         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
2634                 max_stripe_size = 8 * 1024 * 1024;
2635                 max_chunk_size = 2 * max_stripe_size;
2636         } else {
2637                 printk(KERN_ERR "btrfs: invalid chunk type 0x%llx requested\n",
2638                        type);
2639                 BUG_ON(1);
2640         }
2641
2642         /* we don't want a chunk larger than 10% of writeable space */
2643         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
2644                              max_chunk_size);
2645
2646         devices_info = kzalloc(sizeof(*devices_info) * fs_devices->rw_devices,
2647                                GFP_NOFS);
2648         if (!devices_info)
2649                 return -ENOMEM;
2650
2651         cur = fs_devices->alloc_list.next;
2652
2653         /*
2654          * in the first pass through the devices list, we gather information
2655          * about the available holes on each device.
2656          */
2657         ndevs = 0;
2658         while (cur != &fs_devices->alloc_list) {
2659                 struct btrfs_device *device;
2660                 u64 max_avail;
2661                 u64 dev_offset;
2662
2663                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
2664
2665                 cur = cur->next;
2666
2667                 if (!device->writeable) {
2668                         printk(KERN_ERR
2669                                "btrfs: read-only device in alloc_list\n");
2670                         WARN_ON(1);
2671                         continue;
2672                 }
2673
2674                 if (!device->in_fs_metadata)
2675                         continue;
2676
2677                 if (device->total_bytes > device->bytes_used)
2678                         total_avail = device->total_bytes - device->bytes_used;
2679                 else
2680                         total_avail = 0;
2681
2682                 /* If there is no space on this device, skip it. */
2683                 if (total_avail == 0)
2684                         continue;
2685
2686                 ret = find_free_dev_extent(trans, device,
2687                                            max_stripe_size * dev_stripes,
2688                                            &dev_offset, &max_avail);
2689                 if (ret && ret != -ENOSPC)
2690                         goto error;
2691
2692                 if (ret == 0)
2693                         max_avail = max_stripe_size * dev_stripes;
2694
2695                 if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
2696                         continue;
2697
2698                 devices_info[ndevs].dev_offset = dev_offset;
2699                 devices_info[ndevs].max_avail = max_avail;
2700                 devices_info[ndevs].total_avail = total_avail;
2701                 devices_info[ndevs].dev = device;
2702                 ++ndevs;
2703         }
2704
2705         /*
2706          * now sort the devices by hole size / available space
2707          */
2708         sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
2709              btrfs_cmp_device_info, NULL);
2710
2711         /* round down to number of usable stripes */
2712         ndevs -= ndevs % devs_increment;
2713
2714         if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
2715                 ret = -ENOSPC;
2716                 goto error;
2717         }
2718
2719         if (devs_max && ndevs > devs_max)
2720                 ndevs = devs_max;
2721         /*
2722          * the primary goal is to maximize the number of stripes, so use as many
2723          * devices as possible, even if the stripes are not maximum sized.
2724          */
2725         stripe_size = devices_info[ndevs-1].max_avail;
2726         num_stripes = ndevs * dev_stripes;
2727
2728         if (stripe_size * num_stripes > max_chunk_size * ncopies) {
2729                 stripe_size = max_chunk_size * ncopies;
2730                 do_div(stripe_size, num_stripes);
2731         }
2732
2733         do_div(stripe_size, dev_stripes);
2734         do_div(stripe_size, BTRFS_STRIPE_LEN);
2735         stripe_size *= BTRFS_STRIPE_LEN;
2736
2737         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
2738         if (!map) {
2739                 ret = -ENOMEM;
2740                 goto error;
2741         }
2742         map->num_stripes = num_stripes;
2743
2744         for (i = 0; i < ndevs; ++i) {
2745                 for (j = 0; j < dev_stripes; ++j) {
2746                         int s = i * dev_stripes + j;
2747                         map->stripes[s].dev = devices_info[i].dev;
2748                         map->stripes[s].physical = devices_info[i].dev_offset +
2749                                                    j * stripe_size;
2750                 }
2751         }
2752         map->sector_size = extent_root->sectorsize;
2753         map->stripe_len = BTRFS_STRIPE_LEN;
2754         map->io_align = BTRFS_STRIPE_LEN;
2755         map->io_width = BTRFS_STRIPE_LEN;
2756         map->type = type;
2757         map->sub_stripes = sub_stripes;
2758
2759         *map_ret = map;
2760         num_bytes = stripe_size * (num_stripes / ncopies);
2761
2762         *stripe_size_out = stripe_size;
2763         *num_bytes_out = num_bytes;
2764
2765         trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
2766
2767         em = alloc_extent_map();
2768         if (!em) {
2769                 ret = -ENOMEM;
2770                 goto error;
2771         }
2772         em->bdev = (struct block_device *)map;
2773         em->start = start;
2774         em->len = num_bytes;
2775         em->block_start = 0;
2776         em->block_len = em->len;
2777
2778         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
2779         write_lock(&em_tree->lock);
2780         ret = add_extent_mapping(em_tree, em);
2781         write_unlock(&em_tree->lock);
2782         BUG_ON(ret);
2783         free_extent_map(em);
2784
2785         ret = btrfs_make_block_group(trans, extent_root, 0, type,
2786                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2787                                      start, num_bytes);
2788         BUG_ON(ret);
2789
2790         for (i = 0; i < map->num_stripes; ++i) {
2791                 struct btrfs_device *device;
2792                 u64 dev_offset;
2793
2794                 device = map->stripes[i].dev;
2795                 dev_offset = map->stripes[i].physical;
2796
2797                 ret = btrfs_alloc_dev_extent(trans, device,
2798                                 info->chunk_root->root_key.objectid,
2799                                 BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2800                                 start, dev_offset, stripe_size);
2801                 BUG_ON(ret);
2802         }
2803
2804         kfree(devices_info);
2805         return 0;
2806
2807 error:
2808         kfree(map);
2809         kfree(devices_info);
2810         return ret;
2811 }
2812
2813 static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
2814                                 struct btrfs_root *extent_root,
2815                                 struct map_lookup *map, u64 chunk_offset,
2816                                 u64 chunk_size, u64 stripe_size)
2817 {
2818         u64 dev_offset;
2819         struct btrfs_key key;
2820         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
2821         struct btrfs_device *device;
2822         struct btrfs_chunk *chunk;
2823         struct btrfs_stripe *stripe;
2824         size_t item_size = btrfs_chunk_item_size(map->num_stripes);
2825         int index = 0;
2826         int ret;
2827
2828         chunk = kzalloc(item_size, GFP_NOFS);
2829         if (!chunk)
2830                 return -ENOMEM;
2831
2832         index = 0;
2833         while (index < map->num_stripes) {
2834                 device = map->stripes[index].dev;
2835                 device->bytes_used += stripe_size;
2836                 ret = btrfs_update_device(trans, device);
2837                 BUG_ON(ret);
2838                 index++;
2839         }
2840
2841         spin_lock(&extent_root->fs_info->free_chunk_lock);
2842         extent_root->fs_info->free_chunk_space -= (stripe_size *
2843                                                    map->num_stripes);
2844         spin_unlock(&extent_root->fs_info->free_chunk_lock);
2845
2846         index = 0;
2847         stripe = &chunk->stripe;
2848         while (index < map->num_stripes) {
2849                 device = map->stripes[index].dev;
2850                 dev_offset = map->stripes[index].physical;
2851
2852                 btrfs_set_stack_stripe_devid(stripe, device->devid);
2853                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
2854                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
2855                 stripe++;
2856                 index++;
2857         }
2858
2859         btrfs_set_stack_chunk_length(chunk, chunk_size);
2860         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
2861         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
2862         btrfs_set_stack_chunk_type(chunk, map->type);
2863         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
2864         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
2865         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
2866         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
2867         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
2868
2869         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2870         key.type = BTRFS_CHUNK_ITEM_KEY;
2871         key.offset = chunk_offset;
2872
2873         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
2874         BUG_ON(ret);
2875
2876         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2877                 ret = btrfs_add_system_chunk(trans, chunk_root, &key, chunk,
2878                                              item_size);
2879                 BUG_ON(ret);
2880         }
2881
2882         kfree(chunk);
2883         return 0;
2884 }
2885
2886 /*
2887  * Chunk allocation falls into two parts. The first part does works
2888  * that make the new allocated chunk useable, but not do any operation
2889  * that modifies the chunk tree. The second part does the works that
2890  * require modifying the chunk tree. This division is important for the
2891  * bootstrap process of adding storage to a seed btrfs.
2892  */
2893 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
2894                       struct btrfs_root *extent_root, u64 type)
2895 {
2896         u64 chunk_offset;
2897         u64 chunk_size;
2898         u64 stripe_size;
2899         struct map_lookup *map;
2900         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
2901         int ret;
2902
2903         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2904                               &chunk_offset);
2905         if (ret)
2906                 return ret;
2907
2908         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
2909                                   &stripe_size, chunk_offset, type);
2910         if (ret)
2911                 return ret;
2912
2913         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
2914                                    chunk_size, stripe_size);
2915         BUG_ON(ret);
2916         return 0;
2917 }
2918
2919 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
2920                                          struct btrfs_root *root,
2921                                          struct btrfs_device *device)
2922 {
2923         u64 chunk_offset;
2924         u64 sys_chunk_offset;
2925         u64 chunk_size;
2926         u64 sys_chunk_size;
2927         u64 stripe_size;
2928         u64 sys_stripe_size;
2929         u64 alloc_profile;
2930         struct map_lookup *map;
2931         struct map_lookup *sys_map;
2932         struct btrfs_fs_info *fs_info = root->fs_info;
2933         struct btrfs_root *extent_root = fs_info->extent_root;
2934         int ret;
2935
2936         ret = find_next_chunk(fs_info->chunk_root,
2937                               BTRFS_FIRST_CHUNK_TREE_OBJECTID, &chunk_offset);
2938         if (ret)
2939                 return ret;
2940
2941         alloc_profile = BTRFS_BLOCK_GROUP_METADATA |
2942                                 fs_info->avail_metadata_alloc_bits;
2943         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
2944
2945         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
2946                                   &stripe_size, chunk_offset, alloc_profile);
2947         BUG_ON(ret);
2948
2949         sys_chunk_offset = chunk_offset + chunk_size;
2950
2951         alloc_profile = BTRFS_BLOCK_GROUP_SYSTEM |
2952                                 fs_info->avail_system_alloc_bits;
2953         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
2954
2955         ret = __btrfs_alloc_chunk(trans, extent_root, &sys_map,
2956                                   &sys_chunk_size, &sys_stripe_size,
2957                                   sys_chunk_offset, alloc_profile);
2958         BUG_ON(ret);
2959
2960         ret = btrfs_add_device(trans, fs_info->chunk_root, device);
2961         BUG_ON(ret);
2962
2963         /*
2964          * Modifying chunk tree needs allocating new blocks from both
2965          * system block group and metadata block group. So we only can
2966          * do operations require modifying the chunk tree after both
2967          * block groups were created.
2968          */
2969         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
2970                                    chunk_size, stripe_size);
2971         BUG_ON(ret);
2972
2973         ret = __finish_chunk_alloc(trans, extent_root, sys_map,
2974                                    sys_chunk_offset, sys_chunk_size,
2975                                    sys_stripe_size);
2976         BUG_ON(ret);
2977         return 0;
2978 }
2979
2980 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
2981 {
2982         struct extent_map *em;
2983         struct map_lookup *map;
2984         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
2985         int readonly = 0;
2986         int i;
2987
2988         read_lock(&map_tree->map_tree.lock);
2989         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
2990         read_unlock(&map_tree->map_tree.lock);
2991         if (!em)
2992                 return 1;
2993
2994         if (btrfs_test_opt(root, DEGRADED)) {
2995                 free_extent_map(em);
2996                 return 0;
2997         }
2998
2999         map = (struct map_lookup *)em->bdev;
3000         for (i = 0; i < map->num_stripes; i++) {
3001                 if (!map->stripes[i].dev->writeable) {
3002                         readonly = 1;
3003                         break;
3004                 }
3005         }
3006         free_extent_map(em);
3007         return readonly;
3008 }
3009
3010 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
3011 {
3012         extent_map_tree_init(&tree->map_tree);
3013 }
3014
3015 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
3016 {
3017         struct extent_map *em;
3018
3019         while (1) {
3020                 write_lock(&tree->map_tree.lock);
3021                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
3022                 if (em)
3023                         remove_extent_mapping(&tree->map_tree, em);
3024                 write_unlock(&tree->map_tree.lock);
3025                 if (!em)
3026                         break;
3027                 kfree(em->bdev);
3028                 /* once for us */
3029                 free_extent_map(em);
3030                 /* once for the tree */
3031                 free_extent_map(em);
3032         }
3033 }
3034
3035 int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
3036 {
3037         struct extent_map *em;
3038         struct map_lookup *map;
3039         struct extent_map_tree *em_tree = &map_tree->map_tree;
3040         int ret;
3041
3042         read_lock(&em_tree->lock);
3043         em = lookup_extent_mapping(em_tree, logical, len);
3044         read_unlock(&em_tree->lock);
3045         BUG_ON(!em);
3046
3047         BUG_ON(em->start > logical || em->start + em->len < logical);
3048         map = (struct map_lookup *)em->bdev;
3049         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
3050                 ret = map->num_stripes;
3051         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
3052                 ret = map->sub_stripes;
3053         else
3054                 ret = 1;
3055         free_extent_map(em);
3056         return ret;
3057 }
3058
3059 static int find_live_mirror(struct map_lookup *map, int first, int num,
3060                             int optimal)
3061 {
3062         int i;
3063         if (map->stripes[optimal].dev->bdev)
3064                 return optimal;
3065         for (i = first; i < first + num; i++) {
3066                 if (map->stripes[i].dev->bdev)
3067                         return i;
3068         }
3069         /* we couldn't find one that doesn't fail.  Just return something
3070          * and the io error handling code will clean up eventually
3071          */
3072         return optimal;
3073 }
3074
3075 static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
3076                              u64 logical, u64 *length,
3077                              struct btrfs_bio **bbio_ret,
3078                              int mirror_num)
3079 {
3080         struct extent_map *em;
3081         struct map_lookup *map;
3082         struct extent_map_tree *em_tree = &map_tree->map_tree;
3083         u64 offset;
3084         u64 stripe_offset;
3085         u64 stripe_end_offset;
3086         u64 stripe_nr;
3087         u64 stripe_nr_orig;
3088         u64 stripe_nr_end;
3089         int stripes_allocated = 8;
3090         int stripes_required = 1;
3091         int stripe_index;
3092         int i;
3093         int num_stripes;
3094         int max_errors = 0;
3095         struct btrfs_bio *bbio = NULL;
3096
3097         if (bbio_ret && !(rw & (REQ_WRITE | REQ_DISCARD)))
3098                 stripes_allocated = 1;
3099 again:
3100         if (bbio_ret) {
3101                 bbio = kzalloc(btrfs_bio_size(stripes_allocated),
3102                                 GFP_NOFS);
3103                 if (!bbio)
3104                         return -ENOMEM;
3105
3106                 atomic_set(&bbio->error, 0);
3107         }
3108
3109         read_lock(&em_tree->lock);
3110         em = lookup_extent_mapping(em_tree, logical, *length);
3111         read_unlock(&em_tree->lock);
3112
3113         if (!em) {
3114                 printk(KERN_CRIT "unable to find logical %llu len %llu\n",
3115                        (unsigned long long)logical,
3116                        (unsigned long long)*length);
3117                 BUG();
3118         }
3119
3120         BUG_ON(em->start > logical || em->start + em->len < logical);
3121         map = (struct map_lookup *)em->bdev;
3122         offset = logical - em->start;
3123
3124         if (mirror_num > map->num_stripes)
3125                 mirror_num = 0;
3126
3127         /* if our btrfs_bio struct is too small, back off and try again */
3128         if (rw & REQ_WRITE) {
3129                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
3130                                  BTRFS_BLOCK_GROUP_DUP)) {
3131                         stripes_required = map->num_stripes;
3132                         max_errors = 1;
3133                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
3134                         stripes_required = map->sub_stripes;
3135                         max_errors = 1;
3136                 }
3137         }
3138         if (rw & REQ_DISCARD) {
3139                 if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK)
3140                         stripes_required = map->num_stripes;
3141         }
3142         if (bbio_ret && (rw & (REQ_WRITE | REQ_DISCARD)) &&
3143             stripes_allocated < stripes_required) {
3144                 stripes_allocated = map->num_stripes;
3145                 free_extent_map(em);
3146                 kfree(bbio);
3147                 goto again;
3148         }
3149         stripe_nr = offset;
3150         /*
3151          * stripe_nr counts the total number of stripes we have to stride
3152          * to get to this block
3153          */
3154         do_div(stripe_nr, map->stripe_len);
3155
3156         stripe_offset = stripe_nr * map->stripe_len;
3157         BUG_ON(offset < stripe_offset);
3158
3159         /* stripe_offset is the offset of this block in its stripe*/
3160         stripe_offset = offset - stripe_offset;
3161
3162         if (rw & REQ_DISCARD)
3163                 *length = min_t(u64, em->len - offset, *length);
3164         else if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
3165                 /* we limit the length of each bio to what fits in a stripe */
3166                 *length = min_t(u64, em->len - offset,
3167                                 map->stripe_len - stripe_offset);
3168         } else {
3169                 *length = em->len - offset;
3170         }
3171
3172         if (!bbio_ret)
3173                 goto out;
3174
3175         num_stripes = 1;
3176         stripe_index = 0;
3177         stripe_nr_orig = stripe_nr;
3178         stripe_nr_end = (offset + *length + map->stripe_len - 1) &
3179                         (~(map->stripe_len - 1));
3180         do_div(stripe_nr_end, map->stripe_len);
3181         stripe_end_offset = stripe_nr_end * map->stripe_len -
3182                             (offset + *length);
3183         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
3184                 if (rw & REQ_DISCARD)
3185                         num_stripes = min_t(u64, map->num_stripes,
3186                                             stripe_nr_end - stripe_nr_orig);
3187                 stripe_index = do_div(stripe_nr, map->num_stripes);
3188         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
3189                 if (rw & (REQ_WRITE | REQ_DISCARD))
3190                         num_stripes = map->num_stripes;
3191                 else if (mirror_num)
3192                         stripe_index = mirror_num - 1;
3193                 else {
3194                         stripe_index = find_live_mirror(map, 0,
3195                                             map->num_stripes,
3196                                             current->pid % map->num_stripes);
3197                         mirror_num = stripe_index + 1;
3198                 }
3199
3200         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
3201                 if (rw & (REQ_WRITE | REQ_DISCARD)) {
3202                         num_stripes = map->num_stripes;
3203                 } else if (mirror_num) {
3204                         stripe_index = mirror_num - 1;
3205                 } else {
3206                         mirror_num = 1;
3207                 }
3208
3209         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
3210                 int factor = map->num_stripes / map->sub_stripes;
3211
3212                 stripe_index = do_div(stripe_nr, factor);
3213                 stripe_index *= map->sub_stripes;
3214
3215                 if (rw & REQ_WRITE)
3216                         num_stripes = map->sub_stripes;
3217                 else if (rw & REQ_DISCARD)
3218                         num_stripes = min_t(u64, map->sub_stripes *
3219                                             (stripe_nr_end - stripe_nr_orig),
3220                                             map->num_stripes);
3221                 else if (mirror_num)
3222                         stripe_index += mirror_num - 1;
3223                 else {
3224                         stripe_index = find_live_mirror(map, stripe_index,
3225                                               map->sub_stripes, stripe_index +
3226                                               current->pid % map->sub_stripes);
3227                         mirror_num = stripe_index + 1;
3228                 }
3229         } else {
3230                 /*
3231                  * after this do_div call, stripe_nr is the number of stripes
3232                  * on this device we have to walk to find the data, and
3233                  * stripe_index is the number of our device in the stripe array
3234                  */
3235                 stripe_index = do_div(stripe_nr, map->num_stripes);
3236                 mirror_num = stripe_index + 1;
3237         }
3238         BUG_ON(stripe_index >= map->num_stripes);
3239
3240         if (rw & REQ_DISCARD) {
3241                 for (i = 0; i < num_stripes; i++) {
3242                         bbio->stripes[i].physical =
3243                                 map->stripes[stripe_index].physical +
3244                                 stripe_offset + stripe_nr * map->stripe_len;
3245                         bbio->stripes[i].dev = map->stripes[stripe_index].dev;
3246
3247                         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
3248                                 u64 stripes;
3249                                 u32 last_stripe = 0;
3250                                 int j;
3251
3252                                 div_u64_rem(stripe_nr_end - 1,
3253                                             map->num_stripes,
3254                                             &last_stripe);
3255
3256                                 for (j = 0; j < map->num_stripes; j++) {
3257                                         u32 test;
3258
3259                                         div_u64_rem(stripe_nr_end - 1 - j,
3260                                                     map->num_stripes, &test);
3261                                         if (test == stripe_index)
3262                                                 break;
3263                                 }
3264                                 stripes = stripe_nr_end - 1 - j;
3265                                 do_div(stripes, map->num_stripes);
3266                                 bbio->stripes[i].length = map->stripe_len *
3267                                         (stripes - stripe_nr + 1);
3268
3269                                 if (i == 0) {
3270                                         bbio->stripes[i].length -=
3271                                                 stripe_offset;
3272                                         stripe_offset = 0;
3273                                 }
3274                                 if (stripe_index == last_stripe)
3275                                         bbio->stripes[i].length -=
3276                                                 stripe_end_offset;
3277                         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
3278                                 u64 stripes;
3279                                 int j;
3280                                 int factor = map->num_stripes /
3281                                              map->sub_stripes;
3282                                 u32 last_stripe = 0;
3283
3284                                 div_u64_rem(stripe_nr_end - 1,
3285                                             factor, &last_stripe);
3286                                 last_stripe *= map->sub_stripes;
3287
3288                                 for (j = 0; j < factor; j++) {
3289                                         u32 test;
3290
3291                                         div_u64_rem(stripe_nr_end - 1 - j,
3292                                                     factor, &test);
3293
3294                                         if (test ==
3295                                             stripe_index / map->sub_stripes)
3296                                                 break;
3297                                 }
3298                                 stripes = stripe_nr_end - 1 - j;
3299                                 do_div(stripes, factor);
3300                                 bbio->stripes[i].length = map->stripe_len *
3301                                         (stripes - stripe_nr + 1);
3302
3303                                 if (i < map->sub_stripes) {
3304                                         bbio->stripes[i].length -=
3305                                                 stripe_offset;
3306                                         if (i == map->sub_stripes - 1)
3307                                                 stripe_offset = 0;
3308                                 }
3309                                 if (stripe_index >= last_stripe &&
3310                                     stripe_index <= (last_stripe +
3311                                                      map->sub_stripes - 1)) {
3312                                         bbio->stripes[i].length -=
3313                                                 stripe_end_offset;
3314                                 }
3315                         } else
3316                                 bbio->stripes[i].length = *length;
3317
3318                         stripe_index++;
3319                         if (stripe_index == map->num_stripes) {
3320                                 /* This could only happen for RAID0/10 */
3321                                 stripe_index = 0;
3322                                 stripe_nr++;
3323                         }
3324                 }
3325         } else {
3326                 for (i = 0; i < num_stripes; i++) {
3327                         bbio->stripes[i].physical =
3328                                 map->stripes[stripe_index].physical +
3329                                 stripe_offset +
3330                                 stripe_nr * map->stripe_len;
3331                         bbio->stripes[i].dev =
3332                                 map->stripes[stripe_index].dev;
3333                         stripe_index++;
3334                 }
3335         }
3336         if (bbio_ret) {
3337                 *bbio_ret = bbio;
3338                 bbio->num_stripes = num_stripes;
3339                 bbio->max_errors = max_errors;
3340                 bbio->mirror_num = mirror_num;
3341         }
3342 out:
3343         free_extent_map(em);
3344         return 0;
3345 }
3346
3347 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
3348                       u64 logical, u64 *length,
3349                       struct btrfs_bio **bbio_ret, int mirror_num)
3350 {
3351         return __btrfs_map_block(map_tree, rw, logical, length, bbio_ret,
3352                                  mirror_num);
3353 }
3354
3355 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
3356                      u64 chunk_start, u64 physical, u64 devid,
3357                      u64 **logical, int *naddrs, int *stripe_len)
3358 {
3359         struct extent_map_tree *em_tree = &map_tree->map_tree;
3360         struct extent_map *em;
3361         struct map_lookup *map;
3362         u64 *buf;
3363         u64 bytenr;
3364         u64 length;
3365         u64 stripe_nr;
3366         int i, j, nr = 0;
3367
3368         read_lock(&em_tree->lock);
3369         em = lookup_extent_mapping(em_tree, chunk_start, 1);
3370         read_unlock(&em_tree->lock);
3371
3372         BUG_ON(!em || em->start != chunk_start);
3373         map = (struct map_lookup *)em->bdev;
3374
3375         length = em->len;
3376         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
3377                 do_div(length, map->num_stripes / map->sub_stripes);
3378         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
3379                 do_div(length, map->num_stripes);
3380
3381         buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
3382         BUG_ON(!buf);
3383
3384         for (i = 0; i < map->num_stripes; i++) {
3385                 if (devid && map->stripes[i].dev->devid != devid)
3386                         continue;
3387                 if (map->stripes[i].physical > physical ||
3388                     map->stripes[i].physical + length <= physical)
3389                         continue;
3390
3391                 stripe_nr = physical - map->stripes[i].physical;
3392                 do_div(stripe_nr, map->stripe_len);
3393
3394                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
3395                         stripe_nr = stripe_nr * map->num_stripes + i;
3396                         do_div(stripe_nr, map->sub_stripes);
3397                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
3398                         stripe_nr = stripe_nr * map->num_stripes + i;
3399                 }
3400                 bytenr = chunk_start + stripe_nr * map->stripe_len;
3401                 WARN_ON(nr >= map->num_stripes);
3402                 for (j = 0; j < nr; j++) {
3403                         if (buf[j] == bytenr)
3404                                 break;
3405                 }
3406                 if (j == nr) {
3407                         WARN_ON(nr >= map->num_stripes);
3408                         buf[nr++] = bytenr;
3409                 }
3410         }
3411
3412         *logical = buf;
3413         *naddrs = nr;
3414         *stripe_len = map->stripe_len;
3415
3416         free_extent_map(em);
3417         return 0;
3418 }
3419
3420 static void btrfs_end_bio(struct bio *bio, int err)
3421 {
3422         struct btrfs_bio *bbio = bio->bi_private;
3423         int is_orig_bio = 0;
3424
3425         if (err)
3426                 atomic_inc(&bbio->error);
3427
3428         if (bio == bbio->orig_bio)
3429                 is_orig_bio = 1;
3430
3431         if (atomic_dec_and_test(&bbio->stripes_pending)) {
3432                 if (!is_orig_bio) {
3433                         bio_put(bio);
3434                         bio = bbio->orig_bio;
3435                 }
3436                 bio->bi_private = bbio->private;
3437                 bio->bi_end_io = bbio->end_io;
3438                 bio->bi_bdev = (struct block_device *)
3439                                         (unsigned long)bbio->mirror_num;
3440                 /* only send an error to the higher layers if it is
3441                  * beyond the tolerance of the multi-bio
3442                  */
3443                 if (atomic_read(&bbio->error) > bbio->max_errors) {
3444                         err = -EIO;
3445                 } else {
3446                         /*
3447                          * this bio is actually up to date, we didn't
3448                          * go over the max number of errors
3449                          */
3450                         set_bit(BIO_UPTODATE, &bio->bi_flags);
3451                         err = 0;
3452                 }
3453                 kfree(bbio);
3454
3455                 bio_endio(bio, err);
3456         } else if (!is_orig_bio) {
3457                 bio_put(bio);
3458         }
3459 }
3460
3461 struct async_sched {
3462         struct bio *bio;
3463         int rw;
3464         struct btrfs_fs_info *info;
3465         struct btrfs_work work;
3466 };
3467
3468 /*
3469  * see run_scheduled_bios for a description of why bios are collected for
3470  * async submit.
3471  *
3472  * This will add one bio to the pending list for a device and make sure
3473  * the work struct is scheduled.
3474  */
3475 static noinline int schedule_bio(struct btrfs_root *root,
3476                                  struct btrfs_device *device,
3477                                  int rw, struct bio *bio)
3478 {
3479         int should_queue = 1;
3480         struct btrfs_pending_bios *pending_bios;
3481
3482         /* don't bother with additional async steps for reads, right now */
3483         if (!(rw & REQ_WRITE)) {
3484                 bio_get(bio);
3485                 submit_bio(rw, bio);
3486                 bio_put(bio);
3487                 return 0;
3488         }
3489
3490         /*
3491          * nr_async_bios allows us to reliably return congestion to the
3492          * higher layers.  Otherwise, the async bio makes it appear we have
3493          * made progress against dirty pages when we've really just put it
3494          * on a queue for later
3495          */
3496         atomic_inc(&root->fs_info->nr_async_bios);
3497         WARN_ON(bio->bi_next);
3498         bio->bi_next = NULL;
3499         bio->bi_rw |= rw;
3500
3501         spin_lock(&device->io_lock);
3502         if (bio->bi_rw & REQ_SYNC)
3503                 pending_bios = &device->pending_sync_bios;
3504         else
3505                 pending_bios = &device->pending_bios;
3506
3507         if (pending_bios->tail)
3508                 pending_bios->tail->bi_next = bio;
3509
3510         pending_bios->tail = bio;
3511         if (!pending_bios->head)
3512                 pending_bios->head = bio;
3513         if (device->running_pending)
3514                 should_queue = 0;
3515
3516         spin_unlock(&device->io_lock);
3517
3518         if (should_queue)
3519                 btrfs_queue_worker(&root->fs_info->submit_workers,
3520                                    &device->work);
3521         return 0;
3522 }
3523
3524 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
3525                   int mirror_num, int async_submit)
3526 {
3527         struct btrfs_mapping_tree *map_tree;
3528         struct btrfs_device *dev;
3529         struct bio *first_bio = bio;
3530         u64 logical = (u64)bio->bi_sector << 9;
3531         u64 length = 0;
3532         u64 map_length;
3533         int ret;
3534         int dev_nr = 0;
3535         int total_devs = 1;
3536         struct btrfs_bio *bbio = NULL;
3537
3538         length = bio->bi_size;
3539         map_tree = &root->fs_info->mapping_tree;
3540         map_length = length;
3541
3542         ret = btrfs_map_block(map_tree, rw, logical, &map_length, &bbio,
3543                               mirror_num);
3544         BUG_ON(ret);
3545
3546         total_devs = bbio->num_stripes;
3547         if (map_length < length) {
3548                 printk(KERN_CRIT "mapping failed logical %llu bio len %llu "
3549                        "len %llu\n", (unsigned long long)logical,
3550                        (unsigned long long)length,
3551                        (unsigned long long)map_length);
3552                 BUG();
3553         }
3554
3555         bbio->orig_bio = first_bio;
3556         bbio->private = first_bio->bi_private;
3557         bbio->end_io = first_bio->bi_end_io;
3558         atomic_set(&bbio->stripes_pending, bbio->num_stripes);
3559
3560         while (dev_nr < total_devs) {
3561                 if (dev_nr < total_devs - 1) {
3562                         bio = bio_clone(first_bio, GFP_NOFS);
3563                         BUG_ON(!bio);
3564                 } else {
3565                         bio = first_bio;
3566                 }
3567                 bio->bi_private = bbio;
3568                 bio->bi_end_io = btrfs_end_bio;
3569                 bio->bi_sector = bbio->stripes[dev_nr].physical >> 9;
3570                 dev = bbio->stripes[dev_nr].dev;
3571                 if (dev && dev->bdev && (rw != WRITE || dev->writeable)) {
3572                         pr_debug("btrfs_map_bio: rw %d, secor=%llu, dev=%lu "
3573                                  "(%s id %llu), size=%u\n", rw,
3574                                  (u64)bio->bi_sector, (u_long)dev->bdev->bd_dev,
3575                                  dev->name, dev->devid, bio->bi_size);
3576                         bio->bi_bdev = dev->bdev;
3577                         if (async_submit)
3578                                 schedule_bio(root, dev, rw, bio);
3579                         else
3580                                 submit_bio(rw, bio);
3581                 } else {
3582                         bio->bi_bdev = root->fs_info->fs_devices->latest_bdev;
3583                         bio->bi_sector = logical >> 9;
3584                         bio_endio(bio, -EIO);
3585                 }
3586                 dev_nr++;
3587         }
3588         return 0;
3589 }
3590
3591 struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
3592                                        u8 *uuid, u8 *fsid)
3593 {
3594         struct btrfs_device *device;
3595         struct btrfs_fs_devices *cur_devices;
3596
3597         cur_devices = root->fs_info->fs_devices;
3598         while (cur_devices) {
3599                 if (!fsid ||
3600                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
3601                         device = __find_device(&cur_devices->devices,
3602                                                devid, uuid);
3603                         if (device)
3604                                 return device;
3605                 }
3606                 cur_devices = cur_devices->seed;
3607         }
3608         return NULL;
3609 }
3610
3611 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
3612                                             u64 devid, u8 *dev_uuid)
3613 {
3614         struct btrfs_device *device;
3615         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
3616
3617         device = kzalloc(sizeof(*device), GFP_NOFS);
3618         if (!device)
3619                 return NULL;
3620         list_add(&device->dev_list,
3621                  &fs_devices->devices);
3622         device->dev_root = root->fs_info->dev_root;
3623         device->devid = devid;
3624         device->work.func = pending_bios_fn;
3625         device->fs_devices = fs_devices;
3626         device->missing = 1;
3627         fs_devices->num_devices++;
3628         fs_devices->missing_devices++;
3629         spin_lock_init(&device->io_lock);
3630         INIT_LIST_HEAD(&device->dev_alloc_list);
3631         memcpy(device->uuid, dev_uuid, BTRFS_UUID_SIZE);
3632         return device;
3633 }
3634
3635 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
3636                           struct extent_buffer *leaf,
3637                           struct btrfs_chunk *chunk)
3638 {
3639         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
3640         struct map_lookup *map;
3641         struct extent_map *em;
3642         u64 logical;
3643         u64 length;
3644         u64 devid;
3645         u8 uuid[BTRFS_UUID_SIZE];
3646         int num_stripes;
3647         int ret;
3648         int i;
3649
3650         logical = key->offset;
3651         length = btrfs_chunk_length(leaf, chunk);
3652
3653         read_lock(&map_tree->map_tree.lock);
3654         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
3655         read_unlock(&map_tree->map_tree.lock);
3656
3657         /* already mapped? */
3658         if (em && em->start <= logical && em->start + em->len > logical) {
3659                 free_extent_map(em);
3660                 return 0;
3661         } else if (em) {
3662                 free_extent_map(em);
3663         }
3664
3665         em = alloc_extent_map();
3666         if (!em)
3667                 return -ENOMEM;
3668         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3669         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
3670         if (!map) {
3671                 free_extent_map(em);
3672                 return -ENOMEM;
3673         }
3674
3675         em->bdev = (struct block_device *)map;
3676         em->start = logical;
3677         em->len = length;
3678         em->block_start = 0;
3679         em->block_len = em->len;
3680
3681         map->num_stripes = num_stripes;
3682         map->io_width = btrfs_chunk_io_width(leaf, chunk);
3683         map->io_align = btrfs_chunk_io_align(leaf, chunk);
3684         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
3685         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
3686         map->type = btrfs_chunk_type(leaf, chunk);
3687         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
3688         for (i = 0; i < num_stripes; i++) {
3689                 map->stripes[i].physical =
3690                         btrfs_stripe_offset_nr(leaf, chunk, i);
3691                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
3692                 read_extent_buffer(leaf, uuid, (unsigned long)
3693                                    btrfs_stripe_dev_uuid_nr(chunk, i),
3694                                    BTRFS_UUID_SIZE);
3695                 map->stripes[i].dev = btrfs_find_device(root, devid, uuid,
3696                                                         NULL);
3697                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
3698                         kfree(map);
3699                         free_extent_map(em);
3700                         return -EIO;
3701                 }
3702                 if (!map->stripes[i].dev) {
3703                         map->stripes[i].dev =
3704                                 add_missing_dev(root, devid, uuid);
3705                         if (!map->stripes[i].dev) {
3706                                 kfree(map);
3707                                 free_extent_map(em);
3708                                 return -EIO;
3709                         }
3710                 }
3711                 map->stripes[i].dev->in_fs_metadata = 1;
3712         }
3713
3714         write_lock(&map_tree->map_tree.lock);
3715         ret = add_extent_mapping(&map_tree->map_tree, em);
3716         write_unlock(&map_tree->map_tree.lock);
3717         BUG_ON(ret);
3718         free_extent_map(em);
3719
3720         return 0;
3721 }
3722
3723 static int fill_device_from_item(struct extent_buffer *leaf,
3724                                  struct btrfs_dev_item *dev_item,
3725                                  struct btrfs_device *device)
3726 {
3727         unsigned long ptr;
3728
3729         device->devid = btrfs_device_id(leaf, dev_item);
3730         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
3731         device->total_bytes = device->disk_total_bytes;
3732         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
3733         device->type = btrfs_device_type(leaf, dev_item);
3734         device->io_align = btrfs_device_io_align(leaf, dev_item);
3735         device->io_width = btrfs_device_io_width(leaf, dev_item);
3736         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
3737
3738         ptr = (unsigned long)btrfs_device_uuid(dev_item);
3739         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
3740
3741         return 0;
3742 }
3743
3744 static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
3745 {
3746         struct btrfs_fs_devices *fs_devices;
3747         int ret;
3748
3749         mutex_lock(&uuid_mutex);
3750
3751         fs_devices = root->fs_info->fs_devices->seed;
3752         while (fs_devices) {
3753                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
3754                         ret = 0;
3755                         goto out;
3756                 }
3757                 fs_devices = fs_devices->seed;
3758         }
3759
3760         fs_devices = find_fsid(fsid);
3761         if (!fs_devices) {
3762                 ret = -ENOENT;
3763                 goto out;
3764         }
3765
3766         fs_devices = clone_fs_devices(fs_devices);
3767         if (IS_ERR(fs_devices)) {
3768                 ret = PTR_ERR(fs_devices);
3769                 goto out;
3770         }
3771
3772         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
3773                                    root->fs_info->bdev_holder);
3774         if (ret)
3775                 goto out;
3776
3777         if (!fs_devices->seeding) {
3778                 __btrfs_close_devices(fs_devices);
3779                 free_fs_devices(fs_devices);
3780                 ret = -EINVAL;
3781                 goto out;
3782         }
3783
3784         fs_devices->seed = root->fs_info->fs_devices->seed;
3785         root->fs_info->fs_devices->seed = fs_devices;
3786 out:
3787         mutex_unlock(&uuid_mutex);
3788         return ret;
3789 }
3790
3791 static int read_one_dev(struct btrfs_root *root,
3792                         struct extent_buffer *leaf,
3793                         struct btrfs_dev_item *dev_item)
3794 {
3795         struct btrfs_device *device;
3796         u64 devid;
3797         int ret;
3798         u8 fs_uuid[BTRFS_UUID_SIZE];
3799         u8 dev_uuid[BTRFS_UUID_SIZE];
3800
3801         devid = btrfs_device_id(leaf, dev_item);
3802         read_extent_buffer(leaf, dev_uuid,
3803                            (unsigned long)btrfs_device_uuid(dev_item),
3804                            BTRFS_UUID_SIZE);
3805         read_extent_buffer(leaf, fs_uuid,
3806                            (unsigned long)btrfs_device_fsid(dev_item),
3807                            BTRFS_UUID_SIZE);
3808
3809         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
3810                 ret = open_seed_devices(root, fs_uuid);
3811                 if (ret && !btrfs_test_opt(root, DEGRADED))
3812                         return ret;
3813         }
3814
3815         device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
3816         if (!device || !device->bdev) {
3817                 if (!btrfs_test_opt(root, DEGRADED))
3818                         return -EIO;
3819
3820                 if (!device) {
3821                         printk(KERN_WARNING "warning devid %llu missing\n",
3822                                (unsigned long long)devid);
3823                         device = add_missing_dev(root, devid, dev_uuid);
3824                         if (!device)
3825                                 return -ENOMEM;
3826                 } else if (!device->missing) {
3827                         /*
3828                          * this happens when a device that was properly setup
3829                          * in the device info lists suddenly goes bad.
3830                          * device->bdev is NULL, and so we have to set
3831                          * device->missing to one here
3832                          */
3833                         root->fs_info->fs_devices->missing_devices++;
3834                         device->missing = 1;
3835                 }
3836         }
3837
3838         if (device->fs_devices != root->fs_info->fs_devices) {
3839                 BUG_ON(device->writeable);
3840                 if (device->generation !=
3841                     btrfs_device_generation(leaf, dev_item))
3842                         return -EINVAL;
3843         }
3844
3845         fill_device_from_item(leaf, dev_item, device);
3846         device->dev_root = root->fs_info->dev_root;
3847         device->in_fs_metadata = 1;
3848         if (device->writeable) {
3849                 device->fs_devices->total_rw_bytes += device->total_bytes;
3850                 spin_lock(&root->fs_info->free_chunk_lock);
3851                 root->fs_info->free_chunk_space += device->total_bytes -
3852                         device->bytes_used;
3853                 spin_unlock(&root->fs_info->free_chunk_lock);
3854         }
3855         ret = 0;
3856         return ret;
3857 }
3858
3859 int btrfs_read_sys_array(struct btrfs_root *root)
3860 {
3861         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3862         struct extent_buffer *sb;
3863         struct btrfs_disk_key *disk_key;
3864         struct btrfs_chunk *chunk;
3865         u8 *ptr;
3866         unsigned long sb_ptr;
3867         int ret = 0;
3868         u32 num_stripes;
3869         u32 array_size;
3870         u32 len = 0;
3871         u32 cur;
3872         struct btrfs_key key;
3873
3874         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
3875                                           BTRFS_SUPER_INFO_SIZE);
3876         if (!sb)
3877                 return -ENOMEM;
3878         btrfs_set_buffer_uptodate(sb);
3879         btrfs_set_buffer_lockdep_class(root->root_key.objectid, sb, 0);
3880
3881         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
3882         array_size = btrfs_super_sys_array_size(super_copy);
3883
3884         ptr = super_copy->sys_chunk_array;
3885         sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
3886         cur = 0;
3887
3888         while (cur < array_size) {
3889                 disk_key = (struct btrfs_disk_key *)ptr;
3890                 btrfs_disk_key_to_cpu(&key, disk_key);
3891
3892                 len = sizeof(*disk_key); ptr += len;
3893                 sb_ptr += len;
3894                 cur += len;
3895
3896                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
3897                         chunk = (struct btrfs_chunk *)sb_ptr;
3898                         ret = read_one_chunk(root, &key, sb, chunk);
3899                         if (ret)
3900                                 break;
3901                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
3902                         len = btrfs_chunk_item_size(num_stripes);
3903                 } else {
3904                         ret = -EIO;
3905                         break;
3906                 }
3907                 ptr += len;
3908                 sb_ptr += len;
3909                 cur += len;
3910         }
3911         free_extent_buffer(sb);
3912         return ret;
3913 }
3914
3915 int btrfs_read_chunk_tree(struct btrfs_root *root)
3916 {
3917         struct btrfs_path *path;
3918         struct extent_buffer *leaf;
3919         struct btrfs_key key;
3920         struct btrfs_key found_key;
3921         int ret;
3922         int slot;
3923
3924         root = root->fs_info->chunk_root;
3925
3926         path = btrfs_alloc_path();
3927         if (!path)
3928                 return -ENOMEM;
3929
3930         /* first we search for all of the device items, and then we
3931          * read in all of the chunk items.  This way we can create chunk
3932          * mappings that reference all of the devices that are afound
3933          */
3934         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
3935         key.offset = 0;
3936         key.type = 0;
3937 again:
3938         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3939         if (ret < 0)
3940                 goto error;
3941         while (1) {
3942                 leaf = path->nodes[0];
3943                 slot = path->slots[0];
3944                 if (slot >= btrfs_header_nritems(leaf)) {
3945                         ret = btrfs_next_leaf(root, path);
3946                         if (ret == 0)
3947                                 continue;
3948                         if (ret < 0)
3949                                 goto error;
3950                         break;
3951                 }
3952                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3953                 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
3954                         if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
3955                                 break;
3956                         if (found_key.type == BTRFS_DEV_ITEM_KEY) {
3957                                 struct btrfs_dev_item *dev_item;
3958                                 dev_item = btrfs_item_ptr(leaf, slot,
3959                                                   struct btrfs_dev_item);
3960                                 ret = read_one_dev(root, leaf, dev_item);
3961                                 if (ret)
3962                                         goto error;
3963                         }
3964                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
3965                         struct btrfs_chunk *chunk;
3966                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
3967                         ret = read_one_chunk(root, &found_key, leaf, chunk);
3968                         if (ret)
3969                                 goto error;
3970                 }
3971                 path->slots[0]++;
3972         }
3973         if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
3974                 key.objectid = 0;
3975                 btrfs_release_path(path);
3976                 goto again;
3977         }
3978         ret = 0;
3979 error:
3980         btrfs_free_path(path);
3981         return ret;
3982 }