2 * Hypervisor filesystem for Linux on s390.
4 * Copyright IBM Corp. 2006, 2008
5 * Author(s): Michael Holzheu <holzheu@de.ibm.com>
8 #define KMSG_COMPONENT "hypfs"
9 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
11 #include <linux/types.h>
12 #include <linux/errno.h>
14 #include <linux/namei.h>
15 #include <linux/vfs.h>
16 #include <linux/slab.h>
17 #include <linux/pagemap.h>
18 #include <linux/time.h>
19 #include <linux/parser.h>
20 #include <linux/sysfs.h>
21 #include <linux/module.h>
22 #include <linux/seq_file.h>
23 #include <linux/mount.h>
24 #include <linux/aio.h>
25 #include <asm/ebcdic.h>
28 #define HYPFS_MAGIC 0x687970 /* ASCII 'hyp' */
29 #define TMP_SIZE 64 /* size of temporary buffers */
31 static struct dentry *hypfs_create_update_file(struct super_block *sb,
34 struct hypfs_sb_info {
35 kuid_t uid; /* uid used for files and dirs */
36 kgid_t gid; /* gid used for files and dirs */
37 struct dentry *update_file; /* file to trigger update */
38 time_t last_update; /* last update time in secs since 1970 */
39 struct mutex lock; /* lock to protect update process */
42 static const struct file_operations hypfs_file_ops;
43 static struct file_system_type hypfs_type;
44 static const struct super_operations hypfs_s_ops;
46 /* start of list of all dentries, which have to be deleted on update */
47 static struct dentry *hypfs_last_dentry;
49 static void hypfs_update_update(struct super_block *sb)
51 struct hypfs_sb_info *sb_info = sb->s_fs_info;
52 struct inode *inode = sb_info->update_file->d_inode;
54 sb_info->last_update = get_seconds();
55 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
58 /* directory tree removal functions */
60 static void hypfs_add_dentry(struct dentry *dentry)
62 dentry->d_fsdata = hypfs_last_dentry;
63 hypfs_last_dentry = dentry;
66 static inline int hypfs_positive(struct dentry *dentry)
68 return dentry->d_inode && !d_unhashed(dentry);
71 static void hypfs_remove(struct dentry *dentry)
73 struct dentry *parent;
75 parent = dentry->d_parent;
76 mutex_lock(&parent->d_inode->i_mutex);
77 if (hypfs_positive(dentry)) {
78 if (S_ISDIR(dentry->d_inode->i_mode))
79 simple_rmdir(parent->d_inode, dentry);
81 simple_unlink(parent->d_inode, dentry);
85 mutex_unlock(&parent->d_inode->i_mutex);
88 static void hypfs_delete_tree(struct dentry *root)
90 while (hypfs_last_dentry) {
91 struct dentry *next_dentry;
92 next_dentry = hypfs_last_dentry->d_fsdata;
93 hypfs_remove(hypfs_last_dentry);
94 hypfs_last_dentry = next_dentry;
98 static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode)
100 struct inode *ret = new_inode(sb);
103 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
104 ret->i_ino = get_next_ino();
106 ret->i_uid = hypfs_info->uid;
107 ret->i_gid = hypfs_info->gid;
108 ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
115 static void hypfs_evict_inode(struct inode *inode)
118 kfree(inode->i_private);
121 static int hypfs_open(struct inode *inode, struct file *filp)
123 char *data = file_inode(filp)->i_private;
124 struct hypfs_sb_info *fs_info;
126 if (filp->f_mode & FMODE_WRITE) {
127 if (!(inode->i_mode & S_IWUGO))
130 if (filp->f_mode & FMODE_READ) {
131 if (!(inode->i_mode & S_IRUGO))
135 fs_info = inode->i_sb->s_fs_info;
137 mutex_lock(&fs_info->lock);
138 filp->private_data = kstrdup(data, GFP_KERNEL);
139 if (!filp->private_data) {
140 mutex_unlock(&fs_info->lock);
143 mutex_unlock(&fs_info->lock);
145 return nonseekable_open(inode, filp);
148 static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov,
149 unsigned long nr_segs, loff_t offset)
153 struct file *filp = iocb->ki_filp;
155 char __user *buf = iov[0].iov_base;
156 size_t count = iov[0].iov_len;
161 data = filp->private_data;
162 ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data));
171 static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
172 unsigned long nr_segs, loff_t offset)
175 struct super_block *sb = file_inode(iocb->ki_filp)->i_sb;
176 struct hypfs_sb_info *fs_info = sb->s_fs_info;
177 size_t count = iov_length(iov, nr_segs);
180 * Currently we only allow one update per second for two reasons:
181 * 1. diag 204 is VERY expensive
182 * 2. If several processes do updates in parallel and then read the
183 * hypfs data, the likelihood of collisions is reduced, if we restrict
184 * the minimum update interval. A collision occurs, if during the
185 * data gathering of one process another process triggers an update
186 * If the first process wants to ensure consistent data, it has
187 * to restart data collection in this case.
189 mutex_lock(&fs_info->lock);
190 if (fs_info->last_update == get_seconds()) {
194 hypfs_delete_tree(sb->s_root);
196 rc = hypfs_vm_create_files(sb, sb->s_root);
198 rc = hypfs_diag_create_files(sb, sb->s_root);
200 pr_err("Updating the hypfs tree failed\n");
201 hypfs_delete_tree(sb->s_root);
204 hypfs_update_update(sb);
207 mutex_unlock(&fs_info->lock);
211 static int hypfs_release(struct inode *inode, struct file *filp)
213 kfree(filp->private_data);
217 enum { opt_uid, opt_gid, opt_err };
219 static const match_table_t hypfs_tokens = {
225 static int hypfs_parse_options(char *options, struct super_block *sb)
228 substring_t args[MAX_OPT_ARGS];
234 while ((str = strsep(&options, ",")) != NULL) {
236 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
240 token = match_token(str, hypfs_tokens, args);
243 if (match_int(&args[0], &option))
245 uid = make_kuid(current_user_ns(), option);
248 hypfs_info->uid = uid;
251 if (match_int(&args[0], &option))
253 gid = make_kgid(current_user_ns(), option);
256 hypfs_info->gid = gid;
260 pr_err("%s is not a valid mount option\n", str);
267 static int hypfs_show_options(struct seq_file *s, struct dentry *root)
269 struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info;
271 seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid));
272 seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid));
276 static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
278 struct inode *root_inode;
279 struct dentry *root_dentry;
281 struct hypfs_sb_info *sbi;
283 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
286 mutex_init(&sbi->lock);
287 sbi->uid = current_uid();
288 sbi->gid = current_gid();
290 sb->s_blocksize = PAGE_CACHE_SIZE;
291 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
292 sb->s_magic = HYPFS_MAGIC;
293 sb->s_op = &hypfs_s_ops;
294 if (hypfs_parse_options(data, sb))
296 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
299 root_inode->i_op = &simple_dir_inode_operations;
300 root_inode->i_fop = &simple_dir_operations;
301 sb->s_root = root_dentry = d_make_root(root_inode);
305 rc = hypfs_vm_create_files(sb, root_dentry);
307 rc = hypfs_diag_create_files(sb, root_dentry);
310 sbi->update_file = hypfs_create_update_file(sb, root_dentry);
311 if (IS_ERR(sbi->update_file))
312 return PTR_ERR(sbi->update_file);
313 hypfs_update_update(sb);
314 pr_info("Hypervisor filesystem mounted\n");
318 static struct dentry *hypfs_mount(struct file_system_type *fst, int flags,
319 const char *devname, void *data)
321 return mount_single(fst, flags, data, hypfs_fill_super);
324 static void hypfs_kill_super(struct super_block *sb)
326 struct hypfs_sb_info *sb_info = sb->s_fs_info;
329 hypfs_delete_tree(sb->s_root);
330 if (sb_info->update_file)
331 hypfs_remove(sb_info->update_file);
332 kfree(sb->s_fs_info);
333 sb->s_fs_info = NULL;
334 kill_litter_super(sb);
337 static struct dentry *hypfs_create_file(struct super_block *sb,
338 struct dentry *parent, const char *name,
339 char *data, umode_t mode)
341 struct dentry *dentry;
344 mutex_lock(&parent->d_inode->i_mutex);
345 dentry = lookup_one_len(name, parent, strlen(name));
346 if (IS_ERR(dentry)) {
347 dentry = ERR_PTR(-ENOMEM);
350 inode = hypfs_make_inode(sb, mode);
353 dentry = ERR_PTR(-ENOMEM);
357 inode->i_fop = &hypfs_file_ops;
359 inode->i_size = strlen(data);
362 } else if (S_ISDIR(mode)) {
363 inode->i_op = &simple_dir_inode_operations;
364 inode->i_fop = &simple_dir_operations;
365 inc_nlink(parent->d_inode);
368 inode->i_private = data;
369 d_instantiate(dentry, inode);
372 mutex_unlock(&parent->d_inode->i_mutex);
376 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent,
379 struct dentry *dentry;
381 dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE);
384 hypfs_add_dentry(dentry);
388 static struct dentry *hypfs_create_update_file(struct super_block *sb,
391 struct dentry *dentry;
393 dentry = hypfs_create_file(sb, dir, "update", NULL,
394 S_IFREG | UPDATE_FILE_MODE);
396 * We do not put the update file on the 'delete' list with
397 * hypfs_add_dentry(), since it should not be removed when the tree
403 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir,
404 const char *name, __u64 value)
408 struct dentry *dentry;
410 snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value);
411 buffer = kstrdup(tmp, GFP_KERNEL);
413 return ERR_PTR(-ENOMEM);
415 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
416 if (IS_ERR(dentry)) {
418 return ERR_PTR(-ENOMEM);
420 hypfs_add_dentry(dentry);
424 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir,
425 const char *name, char *string)
428 struct dentry *dentry;
430 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
432 return ERR_PTR(-ENOMEM);
433 sprintf(buffer, "%s\n", string);
435 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
436 if (IS_ERR(dentry)) {
438 return ERR_PTR(-ENOMEM);
440 hypfs_add_dentry(dentry);
444 static const struct file_operations hypfs_file_ops = {
446 .release = hypfs_release,
447 .read = do_sync_read,
448 .write = do_sync_write,
449 .aio_read = hypfs_aio_read,
450 .aio_write = hypfs_aio_write,
454 static struct file_system_type hypfs_type = {
455 .owner = THIS_MODULE,
456 .name = "s390_hypfs",
457 .mount = hypfs_mount,
458 .kill_sb = hypfs_kill_super
460 MODULE_ALIAS_FS("s390_hypfs");
462 static const struct super_operations hypfs_s_ops = {
463 .statfs = simple_statfs,
464 .evict_inode = hypfs_evict_inode,
465 .show_options = hypfs_show_options,
468 static struct kobject *s390_kobj;
470 static int __init hypfs_init(void)
474 rc = hypfs_dbfs_init();
477 if (hypfs_diag_init()) {
481 if (hypfs_vm_init()) {
483 goto fail_hypfs_diag_exit;
485 s390_kobj = kobject_create_and_add("s390", hypervisor_kobj);
488 goto fail_hypfs_vm_exit;
490 rc = register_filesystem(&hypfs_type);
492 goto fail_filesystem;
496 kobject_put(s390_kobj);
499 fail_hypfs_diag_exit:
503 pr_err("Initialization of hypfs failed with rc=%i\n", rc);
507 static void __exit hypfs_exit(void)
512 unregister_filesystem(&hypfs_type);
513 kobject_put(s390_kobj);
516 module_init(hypfs_init)
517 module_exit(hypfs_exit)
519 MODULE_LICENSE("GPL");
520 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
521 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");