Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/super.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 5 | * |
| 6 | * super.c contains code to handle: - mount structures |
| 7 | * - super-block tables |
| 8 | * - filesystem drivers list |
| 9 | * - mount system call |
| 10 | * - umount system call |
| 11 | * - ustat system call |
| 12 | * |
| 13 | * GK 2/5/95 - Changed to support mounting the root fs via NFS |
| 14 | * |
| 15 | * Added kerneld support: Jacques Gelinas and Bjorn Ekwall |
| 16 | * Added change_root: Werner Almesberger & Hans Lermen, Feb '96 |
| 17 | * Added options to /proc/mounts: |
Jan Engelhardt | 96de0e2 | 2007-10-19 23:21:04 +0200 | [diff] [blame] | 18 | * Torbjörn Lindh (torbjorn.lindh@gopta.se), April 14, 1996. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | * Added devfs support: Richard Gooch <rgooch@atnf.csiro.au>, 13-JAN-1998 |
| 20 | * Heavily rewritten for 'one fs - one tree' dcache architecture. AV, Mar 2000 |
| 21 | */ |
| 22 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | #include <linux/module.h> |
| 24 | #include <linux/slab.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | #include <linux/acct.h> |
| 26 | #include <linux/blkdev.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | #include <linux/mount.h> |
| 28 | #include <linux/security.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | #include <linux/writeback.h> /* for the emergency remount stuff */ |
| 30 | #include <linux/idr.h> |
Ingo Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 31 | #include <linux/mutex.h> |
Jens Axboe | 5477d0f | 2010-04-29 20:33:35 +0200 | [diff] [blame] | 32 | #include <linux/backing-dev.h> |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 33 | #include <linux/rculist_bl.h> |
Al Viro | 6d59e7f | 2008-03-22 15:48:17 -0400 | [diff] [blame] | 34 | #include "internal.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | |
| 36 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | LIST_HEAD(super_blocks); |
| 38 | DEFINE_SPINLOCK(sb_lock); |
| 39 | |
| 40 | /** |
| 41 | * alloc_super - create new superblock |
Henrik Kretzschmar | fe2bbc4 | 2006-09-06 00:03:41 -0700 | [diff] [blame] | 42 | * @type: filesystem type superblock should belong to |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | * |
| 44 | * Allocates and initializes a new &struct super_block. alloc_super() |
| 45 | * returns a pointer new superblock or %NULL if allocation had failed. |
| 46 | */ |
Ingo Molnar | cf51624 | 2006-07-03 00:25:27 -0700 | [diff] [blame] | 47 | static struct super_block *alloc_super(struct file_system_type *type) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | { |
Oliver Neukum | 11b0b5a | 2006-03-25 03:08:13 -0800 | [diff] [blame] | 49 | struct super_block *s = kzalloc(sizeof(struct super_block), GFP_USER); |
Alexey Dobriyan | b87221d | 2009-09-21 17:01:09 -0700 | [diff] [blame] | 50 | static const struct super_operations default_op; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 51 | |
| 52 | if (s) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 53 | if (security_sb_alloc(s)) { |
| 54 | kfree(s); |
| 55 | s = NULL; |
| 56 | goto out; |
| 57 | } |
Nick Piggin | 6416ccb | 2010-08-18 04:37:38 +1000 | [diff] [blame] | 58 | #ifdef CONFIG_SMP |
| 59 | s->s_files = alloc_percpu(struct list_head); |
| 60 | if (!s->s_files) { |
| 61 | security_sb_free(s); |
| 62 | kfree(s); |
| 63 | s = NULL; |
| 64 | goto out; |
| 65 | } else { |
| 66 | int i; |
| 67 | |
| 68 | for_each_possible_cpu(i) |
| 69 | INIT_LIST_HEAD(per_cpu_ptr(s->s_files, i)); |
| 70 | } |
| 71 | #else |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 72 | INIT_LIST_HEAD(&s->s_files); |
Nick Piggin | 6416ccb | 2010-08-18 04:37:38 +1000 | [diff] [blame] | 73 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | INIT_LIST_HEAD(&s->s_instances); |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 75 | INIT_HLIST_BL_HEAD(&s->s_anon); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 76 | INIT_LIST_HEAD(&s->s_inodes); |
Kentaro Makita | da3bbdd | 2008-07-23 21:27:13 -0700 | [diff] [blame] | 77 | INIT_LIST_HEAD(&s->s_dentry_lru); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | init_rwsem(&s->s_umount); |
Ingo Molnar | 7892f2f | 2006-01-09 15:59:25 -0800 | [diff] [blame] | 79 | mutex_init(&s->s_lock); |
Arjan van de Ven | 897c6ff | 2006-07-03 00:25:28 -0700 | [diff] [blame] | 80 | lockdep_set_class(&s->s_umount, &type->s_umount_key); |
Ingo Molnar | cf51624 | 2006-07-03 00:25:27 -0700 | [diff] [blame] | 81 | /* |
| 82 | * The locking rules for s_lock are up to the |
| 83 | * filesystem. For example ext3fs has different |
| 84 | * lock ordering than usbfs: |
| 85 | */ |
| 86 | lockdep_set_class(&s->s_lock, &type->s_lock_key); |
Peter Zijlstra | ada723d | 2009-02-18 14:48:30 -0800 | [diff] [blame] | 87 | /* |
| 88 | * sget() can have s_umount recursion. |
| 89 | * |
| 90 | * When it cannot find a suitable sb, it allocates a new |
| 91 | * one (this one), and tries again to find a suitable old |
| 92 | * one. |
| 93 | * |
| 94 | * In case that succeeds, it will acquire the s_umount |
| 95 | * lock of the old one. Since these are clearly distrinct |
| 96 | * locks, and this object isn't exposed yet, there's no |
| 97 | * risk of deadlocks. |
| 98 | * |
| 99 | * Annotate this by putting this lock in a different |
| 100 | * subclass. |
| 101 | */ |
| 102 | down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING); |
Al Viro | b20bd1a | 2010-03-22 08:53:19 -0400 | [diff] [blame] | 103 | s->s_count = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | atomic_set(&s->s_active, 1); |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 105 | mutex_init(&s->s_vfs_rename_mutex); |
Roland Dreier | 51ee049 | 2010-04-27 14:23:57 -0700 | [diff] [blame] | 106 | lockdep_set_class(&s->s_vfs_rename_mutex, &type->s_vfs_rename_key); |
Ingo Molnar | d3be915 | 2006-03-23 03:00:29 -0800 | [diff] [blame] | 107 | mutex_init(&s->s_dquot.dqio_mutex); |
| 108 | mutex_init(&s->s_dquot.dqonoff_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 109 | init_rwsem(&s->s_dquot.dqptr_sem); |
| 110 | init_waitqueue_head(&s->s_wait_unfrozen); |
| 111 | s->s_maxbytes = MAX_NON_LFS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 112 | s->s_op = &default_op; |
| 113 | s->s_time_gran = 1000000000; |
| 114 | } |
| 115 | out: |
| 116 | return s; |
| 117 | } |
| 118 | |
| 119 | /** |
| 120 | * destroy_super - frees a superblock |
| 121 | * @s: superblock to free |
| 122 | * |
| 123 | * Frees a superblock. |
| 124 | */ |
| 125 | static inline void destroy_super(struct super_block *s) |
| 126 | { |
Nick Piggin | 6416ccb | 2010-08-18 04:37:38 +1000 | [diff] [blame] | 127 | #ifdef CONFIG_SMP |
| 128 | free_percpu(s->s_files); |
| 129 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | security_sb_free(s); |
Miklos Szeredi | 79c0b2d | 2007-05-08 00:25:43 -0700 | [diff] [blame] | 131 | kfree(s->s_subtype); |
Miklos Szeredi | b3b304a | 2008-02-08 04:21:35 -0800 | [diff] [blame] | 132 | kfree(s->s_options); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 133 | kfree(s); |
| 134 | } |
| 135 | |
| 136 | /* Superblock refcounting */ |
| 137 | |
| 138 | /* |
Al Viro | 35cf7ba | 2010-03-22 21:13:53 -0400 | [diff] [blame] | 139 | * Drop a superblock's refcount. The caller must hold sb_lock. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 140 | */ |
Al Viro | 35cf7ba | 2010-03-22 21:13:53 -0400 | [diff] [blame] | 141 | void __put_super(struct super_block *sb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 142 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 143 | if (!--sb->s_count) { |
Al Viro | 551de6f | 2010-03-22 19:36:35 -0400 | [diff] [blame] | 144 | list_del_init(&sb->s_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 145 | destroy_super(sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 147 | } |
| 148 | |
| 149 | /** |
| 150 | * put_super - drop a temporary reference to superblock |
| 151 | * @sb: superblock in question |
| 152 | * |
| 153 | * Drops a temporary reference, frees superblock if there's no |
| 154 | * references left. |
| 155 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 156 | void put_super(struct super_block *sb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 157 | { |
| 158 | spin_lock(&sb_lock); |
| 159 | __put_super(sb); |
| 160 | spin_unlock(&sb_lock); |
| 161 | } |
| 162 | |
| 163 | |
| 164 | /** |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 165 | * deactivate_locked_super - drop an active reference to superblock |
| 166 | * @s: superblock to deactivate |
| 167 | * |
Al Viro | 1712ac8 | 2010-03-22 15:22:31 -0400 | [diff] [blame] | 168 | * Drops an active reference to superblock, converting it into a temprory |
| 169 | * one if there is no other active references left. In that case we |
| 170 | * tell fs driver to shut it down and drop the temporary reference we |
| 171 | * had just acquired. |
| 172 | * |
| 173 | * Caller holds exclusive lock on superblock; that lock is released. |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 174 | */ |
| 175 | void deactivate_locked_super(struct super_block *s) |
| 176 | { |
| 177 | struct file_system_type *fs = s->s_type; |
Al Viro | b20bd1a | 2010-03-22 08:53:19 -0400 | [diff] [blame] | 178 | if (atomic_dec_and_test(&s->s_active)) { |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 179 | fs->kill_sb(s); |
| 180 | put_filesystem(fs); |
| 181 | put_super(s); |
| 182 | } else { |
| 183 | up_write(&s->s_umount); |
| 184 | } |
| 185 | } |
| 186 | |
| 187 | EXPORT_SYMBOL(deactivate_locked_super); |
| 188 | |
| 189 | /** |
Al Viro | 1712ac8 | 2010-03-22 15:22:31 -0400 | [diff] [blame] | 190 | * deactivate_super - drop an active reference to superblock |
| 191 | * @s: superblock to deactivate |
| 192 | * |
| 193 | * Variant of deactivate_locked_super(), except that superblock is *not* |
| 194 | * locked by caller. If we are going to drop the final active reference, |
| 195 | * lock will be acquired prior to that. |
| 196 | */ |
| 197 | void deactivate_super(struct super_block *s) |
| 198 | { |
| 199 | if (!atomic_add_unless(&s->s_active, -1, 1)) { |
| 200 | down_write(&s->s_umount); |
| 201 | deactivate_locked_super(s); |
| 202 | } |
| 203 | } |
| 204 | |
| 205 | EXPORT_SYMBOL(deactivate_super); |
| 206 | |
| 207 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 208 | * grab_super - acquire an active reference |
| 209 | * @s: reference we are trying to make active |
| 210 | * |
| 211 | * Tries to acquire an active reference. grab_super() is used when we |
| 212 | * had just found a superblock in super_blocks or fs_type->fs_supers |
| 213 | * and want to turn it into a full-blown active reference. grab_super() |
| 214 | * is called with sb_lock held and drops it. Returns 1 in case of |
| 215 | * success, 0 if we had failed (superblock contents was already dead or |
| 216 | * dying when grab_super() had been called). |
| 217 | */ |
Josh Triplett | 9c4dbee | 2006-09-29 01:59:29 -0700 | [diff] [blame] | 218 | static int grab_super(struct super_block *s) __releases(sb_lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 219 | { |
Al Viro | b20bd1a | 2010-03-22 08:53:19 -0400 | [diff] [blame] | 220 | if (atomic_inc_not_zero(&s->s_active)) { |
| 221 | spin_unlock(&sb_lock); |
Al Viro | b20bd1a | 2010-03-22 08:53:19 -0400 | [diff] [blame] | 222 | return 1; |
| 223 | } |
| 224 | /* it's going away */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 225 | s->s_count++; |
| 226 | spin_unlock(&sb_lock); |
Al Viro | 1712ac8 | 2010-03-22 15:22:31 -0400 | [diff] [blame] | 227 | /* wait for it to die */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 228 | down_write(&s->s_umount); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 229 | up_write(&s->s_umount); |
| 230 | put_super(s); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 231 | return 0; |
| 232 | } |
| 233 | |
David Howells | cf9a2ae | 2006-08-29 19:05:54 +0100 | [diff] [blame] | 234 | /* |
Al Viro | 914e263 | 2006-10-18 13:55:46 -0400 | [diff] [blame] | 235 | * Superblock locking. We really ought to get rid of these two. |
| 236 | */ |
| 237 | void lock_super(struct super_block * sb) |
| 238 | { |
| 239 | get_fs_excl(); |
| 240 | mutex_lock(&sb->s_lock); |
| 241 | } |
| 242 | |
| 243 | void unlock_super(struct super_block * sb) |
| 244 | { |
| 245 | put_fs_excl(); |
| 246 | mutex_unlock(&sb->s_lock); |
| 247 | } |
| 248 | |
| 249 | EXPORT_SYMBOL(lock_super); |
| 250 | EXPORT_SYMBOL(unlock_super); |
| 251 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 252 | /** |
| 253 | * generic_shutdown_super - common helper for ->kill_sb() |
| 254 | * @sb: superblock to kill |
| 255 | * |
| 256 | * generic_shutdown_super() does all fs-independent work on superblock |
| 257 | * shutdown. Typical ->kill_sb() should pick all fs-specific objects |
| 258 | * that need destruction out of superblock, call generic_shutdown_super() |
| 259 | * and release aforementioned objects. Note: dentries and inodes _are_ |
| 260 | * taken care of and do not need specific handling. |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 261 | * |
| 262 | * Upon calling this function, the filesystem may no longer alter or |
| 263 | * rearrange the set of dentries belonging to this super_block, nor may it |
| 264 | * change the attachments of dentries to inodes. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 265 | */ |
| 266 | void generic_shutdown_super(struct super_block *sb) |
| 267 | { |
Josef 'Jeff' Sipek | ee9b6d6 | 2007-02-12 00:55:41 -0800 | [diff] [blame] | 268 | const struct super_operations *sop = sb->s_op; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 269 | |
Arjan van de Ven | efaee19 | 2009-01-06 07:20:54 -0800 | [diff] [blame] | 270 | |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 271 | if (sb->s_root) { |
| 272 | shrink_dcache_for_umount(sb); |
Jan Kara | 60b0680 | 2009-04-27 16:43:53 +0200 | [diff] [blame] | 273 | sync_filesystem(sb); |
Al Viro | a9e220f | 2009-05-05 22:10:44 -0400 | [diff] [blame] | 274 | get_fs_excl(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 275 | sb->s_flags &= ~MS_ACTIVE; |
Arjan van de Ven | efaee19 | 2009-01-06 07:20:54 -0800 | [diff] [blame] | 276 | |
Al Viro | 63997e9 | 2010-10-25 20:49:35 -0400 | [diff] [blame] | 277 | fsnotify_unmount_inodes(&sb->s_inodes); |
| 278 | |
| 279 | evict_inodes(sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 280 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 281 | if (sop->put_super) |
| 282 | sop->put_super(sb); |
| 283 | |
Al Viro | 63997e9 | 2010-10-25 20:49:35 -0400 | [diff] [blame] | 284 | if (!list_empty(&sb->s_inodes)) { |
Dave Jones | 7b4fe29 | 2006-02-07 12:58:48 -0800 | [diff] [blame] | 285 | printk("VFS: Busy inodes after unmount of %s. " |
| 286 | "Self-destruct in 5 seconds. Have a nice day...\n", |
| 287 | sb->s_id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 288 | } |
Al Viro | a9e220f | 2009-05-05 22:10:44 -0400 | [diff] [blame] | 289 | put_fs_excl(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 290 | } |
| 291 | spin_lock(&sb_lock); |
| 292 | /* should be initialized for __put_super_and_need_restart() */ |
Al Viro | 551de6f | 2010-03-22 19:36:35 -0400 | [diff] [blame] | 293 | list_del_init(&sb->s_instances); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 294 | spin_unlock(&sb_lock); |
| 295 | up_write(&sb->s_umount); |
| 296 | } |
| 297 | |
| 298 | EXPORT_SYMBOL(generic_shutdown_super); |
| 299 | |
| 300 | /** |
| 301 | * sget - find or create a superblock |
| 302 | * @type: filesystem type superblock should belong to |
| 303 | * @test: comparison callback |
| 304 | * @set: setup callback |
| 305 | * @data: argument to each of them |
| 306 | */ |
| 307 | struct super_block *sget(struct file_system_type *type, |
| 308 | int (*test)(struct super_block *,void *), |
| 309 | int (*set)(struct super_block *,void *), |
| 310 | void *data) |
| 311 | { |
| 312 | struct super_block *s = NULL; |
Matthias Kaehlcke | d473012 | 2007-10-18 23:39:57 -0700 | [diff] [blame] | 313 | struct super_block *old; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 314 | int err; |
| 315 | |
| 316 | retry: |
| 317 | spin_lock(&sb_lock); |
Matthias Kaehlcke | d473012 | 2007-10-18 23:39:57 -0700 | [diff] [blame] | 318 | if (test) { |
| 319 | list_for_each_entry(old, &type->fs_supers, s_instances) { |
| 320 | if (!test(old, data)) |
| 321 | continue; |
| 322 | if (!grab_super(old)) |
| 323 | goto retry; |
Li Zefan | a3cfbb5 | 2009-03-12 14:31:29 -0700 | [diff] [blame] | 324 | if (s) { |
| 325 | up_write(&s->s_umount); |
Matthias Kaehlcke | d473012 | 2007-10-18 23:39:57 -0700 | [diff] [blame] | 326 | destroy_super(s); |
Al Viro | 7a4dec5 | 2010-08-09 12:05:43 -0400 | [diff] [blame] | 327 | s = NULL; |
Li Zefan | a3cfbb5 | 2009-03-12 14:31:29 -0700 | [diff] [blame] | 328 | } |
Al Viro | d3f2147 | 2010-03-23 11:11:05 -0400 | [diff] [blame] | 329 | down_write(&old->s_umount); |
Al Viro | 7a4dec5 | 2010-08-09 12:05:43 -0400 | [diff] [blame] | 330 | if (unlikely(!(old->s_flags & MS_BORN))) { |
| 331 | deactivate_locked_super(old); |
| 332 | goto retry; |
| 333 | } |
Matthias Kaehlcke | d473012 | 2007-10-18 23:39:57 -0700 | [diff] [blame] | 334 | return old; |
| 335 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | } |
| 337 | if (!s) { |
| 338 | spin_unlock(&sb_lock); |
Ingo Molnar | cf51624 | 2006-07-03 00:25:27 -0700 | [diff] [blame] | 339 | s = alloc_super(type); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 340 | if (!s) |
| 341 | return ERR_PTR(-ENOMEM); |
| 342 | goto retry; |
| 343 | } |
| 344 | |
| 345 | err = set(s, data); |
| 346 | if (err) { |
| 347 | spin_unlock(&sb_lock); |
Li Zefan | a3cfbb5 | 2009-03-12 14:31:29 -0700 | [diff] [blame] | 348 | up_write(&s->s_umount); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 349 | destroy_super(s); |
| 350 | return ERR_PTR(err); |
| 351 | } |
| 352 | s->s_type = type; |
| 353 | strlcpy(s->s_id, type->name, sizeof(s->s_id)); |
| 354 | list_add_tail(&s->s_list, &super_blocks); |
| 355 | list_add(&s->s_instances, &type->fs_supers); |
| 356 | spin_unlock(&sb_lock); |
| 357 | get_filesystem(type); |
| 358 | return s; |
| 359 | } |
| 360 | |
| 361 | EXPORT_SYMBOL(sget); |
| 362 | |
| 363 | void drop_super(struct super_block *sb) |
| 364 | { |
| 365 | up_read(&sb->s_umount); |
| 366 | put_super(sb); |
| 367 | } |
| 368 | |
| 369 | EXPORT_SYMBOL(drop_super); |
| 370 | |
Christoph Hellwig | e500475 | 2009-05-05 16:08:56 +0200 | [diff] [blame] | 371 | /** |
| 372 | * sync_supers - helper for periodic superblock writeback |
| 373 | * |
| 374 | * Call the write_super method if present on all dirty superblocks in |
| 375 | * the system. This is for the periodic writeback used by most older |
| 376 | * filesystems. For data integrity superblock writeback use |
| 377 | * sync_filesystems() instead. |
| 378 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 379 | * Note: check the dirty flag before waiting, so we don't |
| 380 | * hold up the sync while mounting a device. (The newly |
| 381 | * mounted device won't need syncing.) |
| 382 | */ |
| 383 | void sync_supers(void) |
| 384 | { |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 385 | struct super_block *sb, *p = NULL; |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 386 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 387 | spin_lock(&sb_lock); |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 388 | list_for_each_entry(sb, &super_blocks, s_list) { |
Al Viro | 551de6f | 2010-03-22 19:36:35 -0400 | [diff] [blame] | 389 | if (list_empty(&sb->s_instances)) |
| 390 | continue; |
Christoph Hellwig | e500475 | 2009-05-05 16:08:56 +0200 | [diff] [blame] | 391 | if (sb->s_op->write_super && sb->s_dirt) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | sb->s_count++; |
| 393 | spin_unlock(&sb_lock); |
Christoph Hellwig | e500475 | 2009-05-05 16:08:56 +0200 | [diff] [blame] | 394 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 395 | down_read(&sb->s_umount); |
Christoph Hellwig | e500475 | 2009-05-05 16:08:56 +0200 | [diff] [blame] | 396 | if (sb->s_root && sb->s_dirt) |
| 397 | sb->s_op->write_super(sb); |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 398 | up_read(&sb->s_umount); |
Christoph Hellwig | e500475 | 2009-05-05 16:08:56 +0200 | [diff] [blame] | 399 | |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 400 | spin_lock(&sb_lock); |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 401 | if (p) |
| 402 | __put_super(p); |
| 403 | p = sb; |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 404 | } |
| 405 | } |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 406 | if (p) |
| 407 | __put_super(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 408 | spin_unlock(&sb_lock); |
| 409 | } |
| 410 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 411 | /** |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 412 | * iterate_supers - call function for all active superblocks |
| 413 | * @f: function to call |
| 414 | * @arg: argument to pass to it |
| 415 | * |
| 416 | * Scans the superblock list and calls given function, passing it |
| 417 | * locked superblock and given argument. |
| 418 | */ |
| 419 | void iterate_supers(void (*f)(struct super_block *, void *), void *arg) |
| 420 | { |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 421 | struct super_block *sb, *p = NULL; |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 422 | |
| 423 | spin_lock(&sb_lock); |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 424 | list_for_each_entry(sb, &super_blocks, s_list) { |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 425 | if (list_empty(&sb->s_instances)) |
| 426 | continue; |
| 427 | sb->s_count++; |
| 428 | spin_unlock(&sb_lock); |
| 429 | |
| 430 | down_read(&sb->s_umount); |
| 431 | if (sb->s_root) |
| 432 | f(sb, arg); |
| 433 | up_read(&sb->s_umount); |
| 434 | |
| 435 | spin_lock(&sb_lock); |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 436 | if (p) |
| 437 | __put_super(p); |
| 438 | p = sb; |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 439 | } |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 440 | if (p) |
| 441 | __put_super(p); |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 442 | spin_unlock(&sb_lock); |
| 443 | } |
| 444 | |
| 445 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 446 | * get_super - get the superblock of a device |
| 447 | * @bdev: device to get the superblock for |
| 448 | * |
| 449 | * Scans the superblock list and finds the superblock of the file system |
| 450 | * mounted on the device given. %NULL is returned if no match is found. |
| 451 | */ |
| 452 | |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 453 | struct super_block *get_super(struct block_device *bdev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 454 | { |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 455 | struct super_block *sb; |
| 456 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 457 | if (!bdev) |
| 458 | return NULL; |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 459 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 460 | spin_lock(&sb_lock); |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 461 | rescan: |
| 462 | list_for_each_entry(sb, &super_blocks, s_list) { |
Al Viro | 551de6f | 2010-03-22 19:36:35 -0400 | [diff] [blame] | 463 | if (list_empty(&sb->s_instances)) |
| 464 | continue; |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 465 | if (sb->s_bdev == bdev) { |
| 466 | sb->s_count++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 467 | spin_unlock(&sb_lock); |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 468 | down_read(&sb->s_umount); |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 469 | /* still alive? */ |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 470 | if (sb->s_root) |
| 471 | return sb; |
| 472 | up_read(&sb->s_umount); |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 473 | /* nope, got unmounted */ |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 474 | spin_lock(&sb_lock); |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 475 | __put_super(sb); |
| 476 | goto rescan; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 477 | } |
| 478 | } |
| 479 | spin_unlock(&sb_lock); |
| 480 | return NULL; |
| 481 | } |
| 482 | |
| 483 | EXPORT_SYMBOL(get_super); |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 484 | |
| 485 | /** |
| 486 | * get_active_super - get an active reference to the superblock of a device |
| 487 | * @bdev: device to get the superblock for |
| 488 | * |
| 489 | * Scans the superblock list and finds the superblock of the file system |
| 490 | * mounted on the device given. Returns the superblock with an active |
Al Viro | d3f2147 | 2010-03-23 11:11:05 -0400 | [diff] [blame] | 491 | * reference or %NULL if none was found. |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 492 | */ |
| 493 | struct super_block *get_active_super(struct block_device *bdev) |
| 494 | { |
| 495 | struct super_block *sb; |
| 496 | |
| 497 | if (!bdev) |
| 498 | return NULL; |
| 499 | |
Al Viro | 1494583 | 2010-03-22 20:15:33 -0400 | [diff] [blame] | 500 | restart: |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 501 | spin_lock(&sb_lock); |
| 502 | list_for_each_entry(sb, &super_blocks, s_list) { |
Al Viro | 551de6f | 2010-03-22 19:36:35 -0400 | [diff] [blame] | 503 | if (list_empty(&sb->s_instances)) |
| 504 | continue; |
Al Viro | 1494583 | 2010-03-22 20:15:33 -0400 | [diff] [blame] | 505 | if (sb->s_bdev == bdev) { |
| 506 | if (grab_super(sb)) /* drops sb_lock */ |
| 507 | return sb; |
| 508 | else |
| 509 | goto restart; |
| 510 | } |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 511 | } |
| 512 | spin_unlock(&sb_lock); |
| 513 | return NULL; |
| 514 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 515 | |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 516 | struct super_block *user_get_super(dev_t dev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 517 | { |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 518 | struct super_block *sb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 519 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 520 | spin_lock(&sb_lock); |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 521 | rescan: |
| 522 | list_for_each_entry(sb, &super_blocks, s_list) { |
Al Viro | 551de6f | 2010-03-22 19:36:35 -0400 | [diff] [blame] | 523 | if (list_empty(&sb->s_instances)) |
| 524 | continue; |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 525 | if (sb->s_dev == dev) { |
| 526 | sb->s_count++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 527 | spin_unlock(&sb_lock); |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 528 | down_read(&sb->s_umount); |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 529 | /* still alive? */ |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 530 | if (sb->s_root) |
| 531 | return sb; |
| 532 | up_read(&sb->s_umount); |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 533 | /* nope, got unmounted */ |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 534 | spin_lock(&sb_lock); |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 535 | __put_super(sb); |
| 536 | goto rescan; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 537 | } |
| 538 | } |
| 539 | spin_unlock(&sb_lock); |
| 540 | return NULL; |
| 541 | } |
| 542 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 543 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 544 | * do_remount_sb - asks filesystem to change mount options. |
| 545 | * @sb: superblock in question |
| 546 | * @flags: numeric part of options |
| 547 | * @data: the rest of options |
| 548 | * @force: whether or not to force the change |
| 549 | * |
| 550 | * Alters the mount options of a mounted file system. |
| 551 | */ |
| 552 | int do_remount_sb(struct super_block *sb, int flags, void *data, int force) |
| 553 | { |
| 554 | int retval; |
Christoph Hellwig | c79d967 | 2010-05-19 07:16:40 -0400 | [diff] [blame] | 555 | int remount_ro; |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 556 | |
| 557 | if (sb->s_frozen != SB_UNFROZEN) |
| 558 | return -EBUSY; |
| 559 | |
David Howells | 9361401 | 2006-09-30 20:45:40 +0200 | [diff] [blame] | 560 | #ifdef CONFIG_BLOCK |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 561 | if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev)) |
| 562 | return -EACCES; |
David Howells | 9361401 | 2006-09-30 20:45:40 +0200 | [diff] [blame] | 563 | #endif |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 564 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 565 | if (flags & MS_RDONLY) |
| 566 | acct_auto_close(sb); |
| 567 | shrink_dcache_sb(sb); |
Jan Kara | 60b0680 | 2009-04-27 16:43:53 +0200 | [diff] [blame] | 568 | sync_filesystem(sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 569 | |
Nick Piggin | d208bbd | 2009-12-21 16:28:53 -0800 | [diff] [blame] | 570 | remount_ro = (flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY); |
Nick Piggin | d208bbd | 2009-12-21 16:28:53 -0800 | [diff] [blame] | 571 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 572 | /* If we are remounting RDONLY and current sb is read/write, |
| 573 | make sure there are no rw files opened */ |
Nick Piggin | d208bbd | 2009-12-21 16:28:53 -0800 | [diff] [blame] | 574 | if (remount_ro) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 575 | if (force) |
| 576 | mark_files_ro(sb); |
J. R. Okajima | b089551 | 2009-06-17 01:16:50 +0900 | [diff] [blame] | 577 | else if (!fs_may_remount_ro(sb)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 578 | return -EBUSY; |
| 579 | } |
| 580 | |
| 581 | if (sb->s_op->remount_fs) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 582 | retval = sb->s_op->remount_fs(sb, &flags, data); |
J. R. Okajima | b089551 | 2009-06-17 01:16:50 +0900 | [diff] [blame] | 583 | if (retval) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 584 | return retval; |
| 585 | } |
| 586 | sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK); |
Christoph Hellwig | c79d967 | 2010-05-19 07:16:40 -0400 | [diff] [blame] | 587 | |
Nick Piggin | d208bbd | 2009-12-21 16:28:53 -0800 | [diff] [blame] | 588 | /* |
| 589 | * Some filesystems modify their metadata via some other path than the |
| 590 | * bdev buffer cache (eg. use a private mapping, or directories in |
| 591 | * pagecache, etc). Also file data modifications go via their own |
| 592 | * mappings. So If we try to mount readonly then copy the filesystem |
| 593 | * from bdev, we could get stale data, so invalidate it to give a best |
| 594 | * effort at coherency. |
| 595 | */ |
| 596 | if (remount_ro && sb->s_bdev) |
| 597 | invalidate_bdev(sb->s_bdev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 598 | return 0; |
| 599 | } |
| 600 | |
Jens Axboe | a2a9537 | 2009-03-17 09:38:40 +0100 | [diff] [blame] | 601 | static void do_emergency_remount(struct work_struct *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 602 | { |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 603 | struct super_block *sb, *p = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 604 | |
| 605 | spin_lock(&sb_lock); |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 606 | list_for_each_entry(sb, &super_blocks, s_list) { |
Al Viro | 551de6f | 2010-03-22 19:36:35 -0400 | [diff] [blame] | 607 | if (list_empty(&sb->s_instances)) |
| 608 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 609 | sb->s_count++; |
| 610 | spin_unlock(&sb_lock); |
Al Viro | 443b94b | 2009-05-05 23:48:50 -0400 | [diff] [blame] | 611 | down_write(&sb->s_umount); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 612 | if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) { |
| 613 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 614 | * What lock protects sb->s_flags?? |
| 615 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 616 | do_remount_sb(sb, MS_RDONLY, NULL, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 617 | } |
Al Viro | 443b94b | 2009-05-05 23:48:50 -0400 | [diff] [blame] | 618 | up_write(&sb->s_umount); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 619 | spin_lock(&sb_lock); |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 620 | if (p) |
| 621 | __put_super(p); |
| 622 | p = sb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 623 | } |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 624 | if (p) |
| 625 | __put_super(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 626 | spin_unlock(&sb_lock); |
Jens Axboe | a2a9537 | 2009-03-17 09:38:40 +0100 | [diff] [blame] | 627 | kfree(work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 628 | printk("Emergency Remount complete\n"); |
| 629 | } |
| 630 | |
| 631 | void emergency_remount(void) |
| 632 | { |
Jens Axboe | a2a9537 | 2009-03-17 09:38:40 +0100 | [diff] [blame] | 633 | struct work_struct *work; |
| 634 | |
| 635 | work = kmalloc(sizeof(*work), GFP_ATOMIC); |
| 636 | if (work) { |
| 637 | INIT_WORK(work, do_emergency_remount); |
| 638 | schedule_work(work); |
| 639 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 640 | } |
| 641 | |
| 642 | /* |
| 643 | * Unnamed block devices are dummy devices used by virtual |
| 644 | * filesystems which don't use real block-devices. -- jrs |
| 645 | */ |
| 646 | |
Alexey Dobriyan | ad76cbc | 2008-08-28 06:26:23 +0400 | [diff] [blame] | 647 | static DEFINE_IDA(unnamed_dev_ida); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 648 | static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */ |
Al Viro | c63e09e | 2009-06-24 02:05:18 -0400 | [diff] [blame] | 649 | static int unnamed_dev_start = 0; /* don't bother trying below it */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 650 | |
| 651 | int set_anon_super(struct super_block *s, void *data) |
| 652 | { |
| 653 | int dev; |
| 654 | int error; |
| 655 | |
| 656 | retry: |
Alexey Dobriyan | ad76cbc | 2008-08-28 06:26:23 +0400 | [diff] [blame] | 657 | if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 658 | return -ENOMEM; |
| 659 | spin_lock(&unnamed_dev_lock); |
Al Viro | c63e09e | 2009-06-24 02:05:18 -0400 | [diff] [blame] | 660 | error = ida_get_new_above(&unnamed_dev_ida, unnamed_dev_start, &dev); |
Al Viro | f21f622 | 2009-06-24 03:12:00 -0400 | [diff] [blame] | 661 | if (!error) |
| 662 | unnamed_dev_start = dev + 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 663 | spin_unlock(&unnamed_dev_lock); |
| 664 | if (error == -EAGAIN) |
| 665 | /* We raced and lost with another CPU. */ |
| 666 | goto retry; |
| 667 | else if (error) |
| 668 | return -EAGAIN; |
| 669 | |
| 670 | if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) { |
| 671 | spin_lock(&unnamed_dev_lock); |
Alexey Dobriyan | ad76cbc | 2008-08-28 06:26:23 +0400 | [diff] [blame] | 672 | ida_remove(&unnamed_dev_ida, dev); |
Al Viro | f21f622 | 2009-06-24 03:12:00 -0400 | [diff] [blame] | 673 | if (unnamed_dev_start > dev) |
| 674 | unnamed_dev_start = dev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 675 | spin_unlock(&unnamed_dev_lock); |
| 676 | return -EMFILE; |
| 677 | } |
| 678 | s->s_dev = MKDEV(0, dev & MINORMASK); |
Jörn Engel | 5129a46 | 2010-04-25 08:54:42 +0200 | [diff] [blame] | 679 | s->s_bdi = &noop_backing_dev_info; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 680 | return 0; |
| 681 | } |
| 682 | |
| 683 | EXPORT_SYMBOL(set_anon_super); |
| 684 | |
| 685 | void kill_anon_super(struct super_block *sb) |
| 686 | { |
| 687 | int slot = MINOR(sb->s_dev); |
| 688 | |
| 689 | generic_shutdown_super(sb); |
| 690 | spin_lock(&unnamed_dev_lock); |
Alexey Dobriyan | ad76cbc | 2008-08-28 06:26:23 +0400 | [diff] [blame] | 691 | ida_remove(&unnamed_dev_ida, slot); |
Al Viro | c63e09e | 2009-06-24 02:05:18 -0400 | [diff] [blame] | 692 | if (slot < unnamed_dev_start) |
| 693 | unnamed_dev_start = slot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 694 | spin_unlock(&unnamed_dev_lock); |
| 695 | } |
| 696 | |
| 697 | EXPORT_SYMBOL(kill_anon_super); |
| 698 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 699 | void kill_litter_super(struct super_block *sb) |
| 700 | { |
| 701 | if (sb->s_root) |
| 702 | d_genocide(sb->s_root); |
| 703 | kill_anon_super(sb); |
| 704 | } |
| 705 | |
| 706 | EXPORT_SYMBOL(kill_litter_super); |
| 707 | |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 708 | static int ns_test_super(struct super_block *sb, void *data) |
| 709 | { |
| 710 | return sb->s_fs_info == data; |
| 711 | } |
| 712 | |
| 713 | static int ns_set_super(struct super_block *sb, void *data) |
| 714 | { |
| 715 | sb->s_fs_info = data; |
| 716 | return set_anon_super(sb, NULL); |
| 717 | } |
| 718 | |
Al Viro | ceefda6 | 2010-07-26 13:16:50 +0400 | [diff] [blame] | 719 | struct dentry *mount_ns(struct file_system_type *fs_type, int flags, |
| 720 | void *data, int (*fill_super)(struct super_block *, void *, int)) |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 721 | { |
| 722 | struct super_block *sb; |
| 723 | |
| 724 | sb = sget(fs_type, ns_test_super, ns_set_super, data); |
| 725 | if (IS_ERR(sb)) |
Al Viro | ceefda6 | 2010-07-26 13:16:50 +0400 | [diff] [blame] | 726 | return ERR_CAST(sb); |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 727 | |
| 728 | if (!sb->s_root) { |
| 729 | int err; |
| 730 | sb->s_flags = flags; |
| 731 | err = fill_super(sb, data, flags & MS_SILENT ? 1 : 0); |
| 732 | if (err) { |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 733 | deactivate_locked_super(sb); |
Al Viro | ceefda6 | 2010-07-26 13:16:50 +0400 | [diff] [blame] | 734 | return ERR_PTR(err); |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 735 | } |
| 736 | |
| 737 | sb->s_flags |= MS_ACTIVE; |
| 738 | } |
| 739 | |
Al Viro | ceefda6 | 2010-07-26 13:16:50 +0400 | [diff] [blame] | 740 | return dget(sb->s_root); |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 741 | } |
| 742 | |
Al Viro | ceefda6 | 2010-07-26 13:16:50 +0400 | [diff] [blame] | 743 | EXPORT_SYMBOL(mount_ns); |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 744 | |
David Howells | 9361401 | 2006-09-30 20:45:40 +0200 | [diff] [blame] | 745 | #ifdef CONFIG_BLOCK |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 746 | static int set_bdev_super(struct super_block *s, void *data) |
| 747 | { |
| 748 | s->s_bdev = data; |
| 749 | s->s_dev = s->s_bdev->bd_dev; |
Jens Axboe | 32a88aa | 2009-09-16 15:02:33 +0200 | [diff] [blame] | 750 | |
| 751 | /* |
| 752 | * We set the bdi here to the queue backing, file systems can |
| 753 | * overwrite this in ->fill_super() |
| 754 | */ |
| 755 | s->s_bdi = &bdev_get_queue(s->s_bdev)->backing_dev_info; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 756 | return 0; |
| 757 | } |
| 758 | |
| 759 | static int test_bdev_super(struct super_block *s, void *data) |
| 760 | { |
| 761 | return (void *)s->s_bdev == data; |
| 762 | } |
| 763 | |
Al Viro | 152a083 | 2010-07-25 00:46:55 +0400 | [diff] [blame] | 764 | struct dentry *mount_bdev(struct file_system_type *fs_type, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 765 | int flags, const char *dev_name, void *data, |
Al Viro | 152a083 | 2010-07-25 00:46:55 +0400 | [diff] [blame] | 766 | int (*fill_super)(struct super_block *, void *, int)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 767 | { |
| 768 | struct block_device *bdev; |
| 769 | struct super_block *s; |
Al Viro | 30c40d2 | 2008-02-22 19:50:45 -0500 | [diff] [blame] | 770 | fmode_t mode = FMODE_READ; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 771 | int error = 0; |
| 772 | |
Al Viro | 30c40d2 | 2008-02-22 19:50:45 -0500 | [diff] [blame] | 773 | if (!(flags & MS_RDONLY)) |
| 774 | mode |= FMODE_WRITE; |
| 775 | |
| 776 | bdev = open_bdev_exclusive(dev_name, mode, fs_type); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 777 | if (IS_ERR(bdev)) |
Al Viro | 152a083 | 2010-07-25 00:46:55 +0400 | [diff] [blame] | 778 | return ERR_CAST(bdev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 779 | |
| 780 | /* |
| 781 | * once the super is inserted into the list by sget, s_umount |
| 782 | * will protect the lockfs code from trying to start a snapshot |
| 783 | * while we are mounting |
| 784 | */ |
Christoph Hellwig | 4fadd7b | 2009-08-03 23:28:06 +0200 | [diff] [blame] | 785 | mutex_lock(&bdev->bd_fsfreeze_mutex); |
| 786 | if (bdev->bd_fsfreeze_count > 0) { |
| 787 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
| 788 | error = -EBUSY; |
| 789 | goto error_bdev; |
| 790 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 791 | s = sget(fs_type, test_bdev_super, set_bdev_super, bdev); |
Christoph Hellwig | 4fadd7b | 2009-08-03 23:28:06 +0200 | [diff] [blame] | 792 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 793 | if (IS_ERR(s)) |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 794 | goto error_s; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 795 | |
| 796 | if (s->s_root) { |
| 797 | if ((flags ^ s->s_flags) & MS_RDONLY) { |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 798 | deactivate_locked_super(s); |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 799 | error = -EBUSY; |
| 800 | goto error_bdev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 801 | } |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 802 | |
Tejun Heo | 4f331f0 | 2010-07-20 15:18:07 -0700 | [diff] [blame] | 803 | /* |
| 804 | * s_umount nests inside bd_mutex during |
| 805 | * __invalidate_device(). close_bdev_exclusive() |
| 806 | * acquires bd_mutex and can't be called under |
| 807 | * s_umount. Drop s_umount temporarily. This is safe |
| 808 | * as we're holding an active reference. |
| 809 | */ |
| 810 | up_write(&s->s_umount); |
Al Viro | 30c40d2 | 2008-02-22 19:50:45 -0500 | [diff] [blame] | 811 | close_bdev_exclusive(bdev, mode); |
Tejun Heo | 4f331f0 | 2010-07-20 15:18:07 -0700 | [diff] [blame] | 812 | down_write(&s->s_umount); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 813 | } else { |
| 814 | char b[BDEVNAME_SIZE]; |
| 815 | |
| 816 | s->s_flags = flags; |
Al Viro | 30c40d2 | 2008-02-22 19:50:45 -0500 | [diff] [blame] | 817 | s->s_mode = mode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 818 | strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id)); |
Pekka Enberg | e78c9a0 | 2006-01-08 01:03:39 -0800 | [diff] [blame] | 819 | sb_set_blocksize(s, block_size(bdev)); |
Theodore Ts'o | 9b04c99 | 2006-03-24 03:15:10 -0800 | [diff] [blame] | 820 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 821 | if (error) { |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 822 | deactivate_locked_super(s); |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 823 | goto error; |
Greg Kroah-Hartman | fa67576 | 2006-02-22 09:39:02 -0800 | [diff] [blame] | 824 | } |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 825 | |
| 826 | s->s_flags |= MS_ACTIVE; |
Theodore Ts'o | 87d8fe1 | 2009-01-03 09:47:09 -0500 | [diff] [blame] | 827 | bdev->bd_super = s; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 828 | } |
| 829 | |
Al Viro | 152a083 | 2010-07-25 00:46:55 +0400 | [diff] [blame] | 830 | return dget(s->s_root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 831 | |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 832 | error_s: |
| 833 | error = PTR_ERR(s); |
| 834 | error_bdev: |
Al Viro | 30c40d2 | 2008-02-22 19:50:45 -0500 | [diff] [blame] | 835 | close_bdev_exclusive(bdev, mode); |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 836 | error: |
Al Viro | 152a083 | 2010-07-25 00:46:55 +0400 | [diff] [blame] | 837 | return ERR_PTR(error); |
| 838 | } |
| 839 | EXPORT_SYMBOL(mount_bdev); |
| 840 | |
| 841 | int get_sb_bdev(struct file_system_type *fs_type, |
| 842 | int flags, const char *dev_name, void *data, |
| 843 | int (*fill_super)(struct super_block *, void *, int), |
| 844 | struct vfsmount *mnt) |
| 845 | { |
| 846 | struct dentry *root; |
| 847 | |
| 848 | root = mount_bdev(fs_type, flags, dev_name, data, fill_super); |
| 849 | if (IS_ERR(root)) |
| 850 | return PTR_ERR(root); |
| 851 | mnt->mnt_root = root; |
| 852 | mnt->mnt_sb = root->d_sb; |
| 853 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 854 | } |
| 855 | |
| 856 | EXPORT_SYMBOL(get_sb_bdev); |
| 857 | |
| 858 | void kill_block_super(struct super_block *sb) |
| 859 | { |
| 860 | struct block_device *bdev = sb->s_bdev; |
Al Viro | 30c40d2 | 2008-02-22 19:50:45 -0500 | [diff] [blame] | 861 | fmode_t mode = sb->s_mode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 862 | |
H Hartley Sweeten | ddbaaf3 | 2009-04-29 20:14:57 -0400 | [diff] [blame] | 863 | bdev->bd_super = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 864 | generic_shutdown_super(sb); |
| 865 | sync_blockdev(bdev); |
Al Viro | 30c40d2 | 2008-02-22 19:50:45 -0500 | [diff] [blame] | 866 | close_bdev_exclusive(bdev, mode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 867 | } |
| 868 | |
| 869 | EXPORT_SYMBOL(kill_block_super); |
David Howells | 9361401 | 2006-09-30 20:45:40 +0200 | [diff] [blame] | 870 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 871 | |
Al Viro | 3c26ff6 | 2010-07-25 11:46:36 +0400 | [diff] [blame] | 872 | struct dentry *mount_nodev(struct file_system_type *fs_type, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 873 | int flags, void *data, |
Al Viro | 3c26ff6 | 2010-07-25 11:46:36 +0400 | [diff] [blame] | 874 | int (*fill_super)(struct super_block *, void *, int)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 875 | { |
| 876 | int error; |
| 877 | struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); |
| 878 | |
| 879 | if (IS_ERR(s)) |
Al Viro | 3c26ff6 | 2010-07-25 11:46:36 +0400 | [diff] [blame] | 880 | return ERR_CAST(s); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 881 | |
| 882 | s->s_flags = flags; |
| 883 | |
Theodore Ts'o | 9b04c99 | 2006-03-24 03:15:10 -0800 | [diff] [blame] | 884 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 885 | if (error) { |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 886 | deactivate_locked_super(s); |
Al Viro | 3c26ff6 | 2010-07-25 11:46:36 +0400 | [diff] [blame] | 887 | return ERR_PTR(error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 888 | } |
| 889 | s->s_flags |= MS_ACTIVE; |
Al Viro | 3c26ff6 | 2010-07-25 11:46:36 +0400 | [diff] [blame] | 890 | return dget(s->s_root); |
| 891 | } |
| 892 | EXPORT_SYMBOL(mount_nodev); |
| 893 | |
| 894 | int get_sb_nodev(struct file_system_type *fs_type, |
| 895 | int flags, void *data, |
| 896 | int (*fill_super)(struct super_block *, void *, int), |
| 897 | struct vfsmount *mnt) |
| 898 | { |
| 899 | struct dentry *root; |
| 900 | |
| 901 | root = mount_nodev(fs_type, flags, data, fill_super); |
| 902 | if (IS_ERR(root)) |
| 903 | return PTR_ERR(root); |
| 904 | mnt->mnt_root = root; |
| 905 | mnt->mnt_sb = root->d_sb; |
Sukadev Bhattiprolu | a3ec947 | 2009-03-04 12:06:34 -0800 | [diff] [blame] | 906 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 907 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 908 | EXPORT_SYMBOL(get_sb_nodev); |
| 909 | |
| 910 | static int compare_single(struct super_block *s, void *p) |
| 911 | { |
| 912 | return 1; |
| 913 | } |
| 914 | |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 915 | struct dentry *mount_single(struct file_system_type *fs_type, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 916 | int flags, void *data, |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 917 | int (*fill_super)(struct super_block *, void *, int)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 918 | { |
| 919 | struct super_block *s; |
| 920 | int error; |
| 921 | |
| 922 | s = sget(fs_type, compare_single, set_anon_super, NULL); |
| 923 | if (IS_ERR(s)) |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 924 | return ERR_CAST(s); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 925 | if (!s->s_root) { |
| 926 | s->s_flags = flags; |
Theodore Ts'o | 9b04c99 | 2006-03-24 03:15:10 -0800 | [diff] [blame] | 927 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 928 | if (error) { |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 929 | deactivate_locked_super(s); |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 930 | return ERR_PTR(error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 931 | } |
| 932 | s->s_flags |= MS_ACTIVE; |
Kay Sievers | 9329d1b | 2009-12-18 21:18:15 +0100 | [diff] [blame] | 933 | } else { |
| 934 | do_remount_sb(s, flags, data, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 935 | } |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 936 | return dget(s->s_root); |
| 937 | } |
| 938 | EXPORT_SYMBOL(mount_single); |
| 939 | |
| 940 | int get_sb_single(struct file_system_type *fs_type, |
| 941 | int flags, void *data, |
| 942 | int (*fill_super)(struct super_block *, void *, int), |
| 943 | struct vfsmount *mnt) |
| 944 | { |
| 945 | struct dentry *root; |
| 946 | root = mount_single(fs_type, flags, data, fill_super); |
| 947 | if (IS_ERR(root)) |
| 948 | return PTR_ERR(root); |
| 949 | mnt->mnt_root = root; |
| 950 | mnt->mnt_sb = root->d_sb; |
Sukadev Bhattiprolu | a3ec947 | 2009-03-04 12:06:34 -0800 | [diff] [blame] | 951 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 952 | } |
| 953 | |
| 954 | EXPORT_SYMBOL(get_sb_single); |
| 955 | |
| 956 | struct vfsmount * |
Trond Myklebust | bb4a58b | 2006-06-09 09:34:15 -0400 | [diff] [blame] | 957 | vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 958 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 959 | struct vfsmount *mnt; |
Al Viro | c96e41e | 2010-07-25 00:17:56 +0400 | [diff] [blame] | 960 | struct dentry *root; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 961 | char *secdata = NULL; |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 962 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 963 | |
| 964 | if (!type) |
| 965 | return ERR_PTR(-ENODEV); |
| 966 | |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 967 | error = -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 968 | mnt = alloc_vfsmnt(name); |
| 969 | if (!mnt) |
| 970 | goto out; |
| 971 | |
Al Viro | 8089352 | 2010-02-05 09:30:46 -0500 | [diff] [blame] | 972 | if (flags & MS_KERNMOUNT) |
| 973 | mnt->mnt_flags = MNT_INTERNAL; |
| 974 | |
Eric Paris | e000752 | 2008-03-05 10:31:54 -0500 | [diff] [blame] | 975 | if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 976 | secdata = alloc_secdata(); |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 977 | if (!secdata) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 978 | goto out_mnt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 979 | |
Eric Paris | e000752 | 2008-03-05 10:31:54 -0500 | [diff] [blame] | 980 | error = security_sb_copy_data(data, secdata); |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 981 | if (error) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 982 | goto out_free_secdata; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 983 | } |
| 984 | |
Al Viro | c96e41e | 2010-07-25 00:17:56 +0400 | [diff] [blame] | 985 | if (type->mount) { |
| 986 | root = type->mount(type, flags, name, data); |
| 987 | if (IS_ERR(root)) { |
| 988 | error = PTR_ERR(root); |
| 989 | goto out_free_secdata; |
| 990 | } |
| 991 | mnt->mnt_root = root; |
| 992 | mnt->mnt_sb = root->d_sb; |
| 993 | } else { |
| 994 | error = type->get_sb(type, flags, name, data, mnt); |
| 995 | if (error < 0) |
| 996 | goto out_free_secdata; |
| 997 | } |
Lee Schermerhorn | b4c07bc | 2007-07-15 23:40:54 -0700 | [diff] [blame] | 998 | BUG_ON(!mnt->mnt_sb); |
Jörn Engel | 5129a46 | 2010-04-25 08:54:42 +0200 | [diff] [blame] | 999 | WARN_ON(!mnt->mnt_sb->s_bdi); |
Al Viro | 7a4dec5 | 2010-08-09 12:05:43 -0400 | [diff] [blame] | 1000 | mnt->mnt_sb->s_flags |= MS_BORN; |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1001 | |
Jörn Engel | 5129a46 | 2010-04-25 08:54:42 +0200 | [diff] [blame] | 1002 | error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata); |
| 1003 | if (error) |
| 1004 | goto out_sb; |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1005 | |
Jeff Layton | 42cb56a | 2009-09-18 13:05:53 -0700 | [diff] [blame] | 1006 | /* |
| 1007 | * filesystems should never set s_maxbytes larger than MAX_LFS_FILESIZE |
| 1008 | * but s_maxbytes was an unsigned long long for many releases. Throw |
| 1009 | * this warning for a little while to try and catch filesystems that |
| 1010 | * violate this rule. This warning should be either removed or |
| 1011 | * converted to a BUG() in 2.6.34. |
| 1012 | */ |
| 1013 | WARN((mnt->mnt_sb->s_maxbytes < 0), "%s set sb->s_maxbytes to " |
| 1014 | "negative value (%lld)\n", type->name, mnt->mnt_sb->s_maxbytes); |
| 1015 | |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1016 | mnt->mnt_mountpoint = mnt->mnt_root; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1017 | mnt->mnt_parent = mnt; |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1018 | up_write(&mnt->mnt_sb->s_umount); |
Gerald Schaefer | 8680e22 | 2005-06-21 17:15:16 -0700 | [diff] [blame] | 1019 | free_secdata(secdata); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1020 | return mnt; |
| 1021 | out_sb: |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1022 | dput(mnt->mnt_root); |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 1023 | deactivate_locked_super(mnt->mnt_sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1024 | out_free_secdata: |
| 1025 | free_secdata(secdata); |
| 1026 | out_mnt: |
| 1027 | free_vfsmnt(mnt); |
| 1028 | out: |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1029 | return ERR_PTR(error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1030 | } |
| 1031 | |
Trond Myklebust | bb4a58b | 2006-06-09 09:34:15 -0400 | [diff] [blame] | 1032 | EXPORT_SYMBOL_GPL(vfs_kern_mount); |
| 1033 | |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1034 | /** |
Randy Dunlap | 7000d3c | 2010-05-24 22:22:34 -0700 | [diff] [blame] | 1035 | * freeze_super - lock the filesystem and force it into a consistent state |
| 1036 | * @sb: the super to lock |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1037 | * |
| 1038 | * Syncs the super to make sure the filesystem is consistent and calls the fs's |
| 1039 | * freeze_fs. Subsequent calls to this without first thawing the fs will return |
| 1040 | * -EBUSY. |
| 1041 | */ |
| 1042 | int freeze_super(struct super_block *sb) |
| 1043 | { |
| 1044 | int ret; |
| 1045 | |
| 1046 | atomic_inc(&sb->s_active); |
| 1047 | down_write(&sb->s_umount); |
| 1048 | if (sb->s_frozen) { |
| 1049 | deactivate_locked_super(sb); |
| 1050 | return -EBUSY; |
| 1051 | } |
| 1052 | |
| 1053 | if (sb->s_flags & MS_RDONLY) { |
| 1054 | sb->s_frozen = SB_FREEZE_TRANS; |
| 1055 | smp_wmb(); |
| 1056 | up_write(&sb->s_umount); |
| 1057 | return 0; |
| 1058 | } |
| 1059 | |
| 1060 | sb->s_frozen = SB_FREEZE_WRITE; |
| 1061 | smp_wmb(); |
| 1062 | |
| 1063 | sync_filesystem(sb); |
| 1064 | |
| 1065 | sb->s_frozen = SB_FREEZE_TRANS; |
| 1066 | smp_wmb(); |
| 1067 | |
| 1068 | sync_blockdev(sb->s_bdev); |
| 1069 | if (sb->s_op->freeze_fs) { |
| 1070 | ret = sb->s_op->freeze_fs(sb); |
| 1071 | if (ret) { |
| 1072 | printk(KERN_ERR |
| 1073 | "VFS:Filesystem freeze failed\n"); |
| 1074 | sb->s_frozen = SB_UNFROZEN; |
| 1075 | deactivate_locked_super(sb); |
| 1076 | return ret; |
| 1077 | } |
| 1078 | } |
| 1079 | up_write(&sb->s_umount); |
| 1080 | return 0; |
| 1081 | } |
| 1082 | EXPORT_SYMBOL(freeze_super); |
| 1083 | |
| 1084 | /** |
| 1085 | * thaw_super -- unlock filesystem |
| 1086 | * @sb: the super to thaw |
| 1087 | * |
| 1088 | * Unlocks the filesystem and marks it writeable again after freeze_super(). |
| 1089 | */ |
| 1090 | int thaw_super(struct super_block *sb) |
| 1091 | { |
| 1092 | int error; |
| 1093 | |
| 1094 | down_write(&sb->s_umount); |
| 1095 | if (sb->s_frozen == SB_UNFROZEN) { |
| 1096 | up_write(&sb->s_umount); |
| 1097 | return -EINVAL; |
| 1098 | } |
| 1099 | |
| 1100 | if (sb->s_flags & MS_RDONLY) |
| 1101 | goto out; |
| 1102 | |
| 1103 | if (sb->s_op->unfreeze_fs) { |
| 1104 | error = sb->s_op->unfreeze_fs(sb); |
| 1105 | if (error) { |
| 1106 | printk(KERN_ERR |
| 1107 | "VFS:Filesystem thaw failed\n"); |
| 1108 | sb->s_frozen = SB_FREEZE_TRANS; |
| 1109 | up_write(&sb->s_umount); |
| 1110 | return error; |
| 1111 | } |
| 1112 | } |
| 1113 | |
| 1114 | out: |
| 1115 | sb->s_frozen = SB_UNFROZEN; |
| 1116 | smp_wmb(); |
| 1117 | wake_up(&sb->s_wait_unfrozen); |
| 1118 | deactivate_locked_super(sb); |
| 1119 | |
| 1120 | return 0; |
| 1121 | } |
| 1122 | EXPORT_SYMBOL(thaw_super); |
| 1123 | |
Miklos Szeredi | 79c0b2d | 2007-05-08 00:25:43 -0700 | [diff] [blame] | 1124 | static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype) |
| 1125 | { |
| 1126 | int err; |
| 1127 | const char *subtype = strchr(fstype, '.'); |
| 1128 | if (subtype) { |
| 1129 | subtype++; |
| 1130 | err = -EINVAL; |
| 1131 | if (!subtype[0]) |
| 1132 | goto err; |
| 1133 | } else |
| 1134 | subtype = ""; |
| 1135 | |
| 1136 | mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL); |
| 1137 | err = -ENOMEM; |
| 1138 | if (!mnt->mnt_sb->s_subtype) |
| 1139 | goto err; |
| 1140 | return mnt; |
| 1141 | |
| 1142 | err: |
Nick Piggin | b3e19d9 | 2011-01-07 17:50:11 +1100 | [diff] [blame] | 1143 | mntput_long(mnt); |
Miklos Szeredi | 79c0b2d | 2007-05-08 00:25:43 -0700 | [diff] [blame] | 1144 | return ERR_PTR(err); |
| 1145 | } |
| 1146 | |
Trond Myklebust | bb4a58b | 2006-06-09 09:34:15 -0400 | [diff] [blame] | 1147 | struct vfsmount * |
| 1148 | do_kern_mount(const char *fstype, int flags, const char *name, void *data) |
| 1149 | { |
| 1150 | struct file_system_type *type = get_fs_type(fstype); |
| 1151 | struct vfsmount *mnt; |
| 1152 | if (!type) |
| 1153 | return ERR_PTR(-ENODEV); |
| 1154 | mnt = vfs_kern_mount(type, flags, name, data); |
Miklos Szeredi | 79c0b2d | 2007-05-08 00:25:43 -0700 | [diff] [blame] | 1155 | if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) && |
| 1156 | !mnt->mnt_sb->s_subtype) |
| 1157 | mnt = fs_set_subtype(mnt, fstype); |
Trond Myklebust | bb4a58b | 2006-06-09 09:34:15 -0400 | [diff] [blame] | 1158 | put_filesystem(type); |
| 1159 | return mnt; |
| 1160 | } |
Al Viro | 8a4e98d | 2008-02-24 01:43:03 -0500 | [diff] [blame] | 1161 | EXPORT_SYMBOL_GPL(do_kern_mount); |
Trond Myklebust | bb4a58b | 2006-06-09 09:34:15 -0400 | [diff] [blame] | 1162 | |
Pavel Emelyanov | 8bf9725 | 2007-10-18 23:40:02 -0700 | [diff] [blame] | 1163 | struct vfsmount *kern_mount_data(struct file_system_type *type, void *data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1164 | { |
Pavel Emelyanov | 8bf9725 | 2007-10-18 23:40:02 -0700 | [diff] [blame] | 1165 | return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1166 | } |
| 1167 | |
Pavel Emelyanov | 8bf9725 | 2007-10-18 23:40:02 -0700 | [diff] [blame] | 1168 | EXPORT_SYMBOL_GPL(kern_mount_data); |