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 | |
Paul Gortmaker | 630d9c4 | 2011-11-16 23:57:37 -0500 | [diff] [blame] | 23 | #include <linux/export.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | #include <linux/slab.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | #include <linux/blkdev.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 26 | #include <linux/mount.h> |
| 27 | #include <linux/security.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | #include <linux/writeback.h> /* for the emergency remount stuff */ |
| 29 | #include <linux/idr.h> |
Ingo Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 30 | #include <linux/mutex.h> |
Jens Axboe | 5477d0f | 2010-04-29 20:33:35 +0200 | [diff] [blame] | 31 | #include <linux/backing-dev.h> |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 32 | #include <linux/rculist_bl.h> |
Dan Magenheimer | c515e1f | 2011-05-26 10:01:43 -0600 | [diff] [blame] | 33 | #include <linux/cleancache.h> |
Al Viro | 4040153 | 2012-02-13 03:58:52 +0000 | [diff] [blame] | 34 | #include <linux/fsnotify.h> |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 35 | #include <linux/lockdep.h> |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 36 | #include <linux/user_namespace.h> |
Al Viro | 6d59e7f | 2008-03-22 15:48:17 -0400 | [diff] [blame] | 37 | #include "internal.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | |
| 39 | |
Al Viro | 15d0f5e | 2015-02-02 10:07:59 -0700 | [diff] [blame] | 40 | static LIST_HEAD(super_blocks); |
| 41 | static DEFINE_SPINLOCK(sb_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 43 | static char *sb_writers_name[SB_FREEZE_LEVELS] = { |
| 44 | "sb_writers", |
| 45 | "sb_pagefaults", |
| 46 | "sb_internal", |
| 47 | }; |
| 48 | |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 49 | /* |
| 50 | * One thing we have to be careful of with a per-sb shrinker is that we don't |
| 51 | * drop the last active reference to the superblock from within the shrinker. |
| 52 | * If that happens we could trigger unregistering the shrinker from within the |
| 53 | * shrinker path and that leads to deadlock on the shrinker_rwsem. Hence we |
| 54 | * take a passive reference to the superblock to avoid this from occurring. |
| 55 | */ |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 56 | static unsigned long super_cache_scan(struct shrinker *shrink, |
| 57 | struct shrink_control *sc) |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 58 | { |
| 59 | struct super_block *sb; |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 60 | long fs_objects = 0; |
| 61 | long total_objects; |
| 62 | long freed = 0; |
| 63 | long dentries; |
| 64 | long inodes; |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 65 | |
| 66 | sb = container_of(shrink, struct super_block, s_shrink); |
| 67 | |
| 68 | /* |
| 69 | * Deadlock avoidance. We may hold various FS locks, and we don't want |
| 70 | * to recurse into the FS that called us in clear_inode() and friends.. |
| 71 | */ |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 72 | if (!(sc->gfp_mask & __GFP_FS)) |
| 73 | return SHRINK_STOP; |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 74 | |
Konstantin Khlebnikov | eb6ef3d | 2015-02-19 20:19:35 +0300 | [diff] [blame] | 75 | if (!trylock_super(sb)) |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 76 | return SHRINK_STOP; |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 77 | |
Al Viro | d040790 | 2013-07-19 21:12:31 +0400 | [diff] [blame] | 78 | if (sb->s_op->nr_cached_objects) |
Vladimir Davydov | 4101b62 | 2015-02-12 14:58:51 -0800 | [diff] [blame] | 79 | fs_objects = sb->s_op->nr_cached_objects(sb, sc); |
Dave Chinner | 0e1fdaf | 2011-07-08 14:14:44 +1000 | [diff] [blame] | 80 | |
Vladimir Davydov | 503c358 | 2015-02-12 14:58:47 -0800 | [diff] [blame] | 81 | inodes = list_lru_shrink_count(&sb->s_inode_lru, sc); |
| 82 | dentries = list_lru_shrink_count(&sb->s_dentry_lru, sc); |
Dave Chinner | f604156 | 2013-08-28 10:18:00 +1000 | [diff] [blame] | 83 | total_objects = dentries + inodes + fs_objects + 1; |
Tetsuo Handa | 475d0db | 2014-05-17 20:56:38 +0900 | [diff] [blame] | 84 | if (!total_objects) |
| 85 | total_objects = 1; |
Dave Chinner | 0e1fdaf | 2011-07-08 14:14:44 +1000 | [diff] [blame] | 86 | |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 87 | /* proportion the scan between the caches */ |
Dave Chinner | f604156 | 2013-08-28 10:18:00 +1000 | [diff] [blame] | 88 | dentries = mult_frac(sc->nr_to_scan, dentries, total_objects); |
Dave Chinner | bc3b14c | 2013-08-28 10:17:58 +1000 | [diff] [blame] | 89 | inodes = mult_frac(sc->nr_to_scan, inodes, total_objects); |
Vladimir Davydov | 503c358 | 2015-02-12 14:58:47 -0800 | [diff] [blame] | 90 | fs_objects = mult_frac(sc->nr_to_scan, fs_objects, total_objects); |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 91 | |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 92 | /* |
| 93 | * prune the dcache first as the icache is pinned by it, then |
| 94 | * prune the icache, followed by the filesystem specific caches |
Vladimir Davydov | 49e7e7f | 2015-02-12 14:59:17 -0800 | [diff] [blame] | 95 | * |
| 96 | * Ensure that we always scan at least one object - memcg kmem |
| 97 | * accounting uses this to fully empty the caches. |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 98 | */ |
Vladimir Davydov | 49e7e7f | 2015-02-12 14:59:17 -0800 | [diff] [blame] | 99 | sc->nr_to_scan = dentries + 1; |
Vladimir Davydov | 503c358 | 2015-02-12 14:58:47 -0800 | [diff] [blame] | 100 | freed = prune_dcache_sb(sb, sc); |
Vladimir Davydov | 49e7e7f | 2015-02-12 14:59:17 -0800 | [diff] [blame] | 101 | sc->nr_to_scan = inodes + 1; |
Vladimir Davydov | 503c358 | 2015-02-12 14:58:47 -0800 | [diff] [blame] | 102 | freed += prune_icache_sb(sb, sc); |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 103 | |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 104 | if (fs_objects) { |
Vladimir Davydov | 49e7e7f | 2015-02-12 14:59:17 -0800 | [diff] [blame] | 105 | sc->nr_to_scan = fs_objects + 1; |
Vladimir Davydov | 4101b62 | 2015-02-12 14:58:51 -0800 | [diff] [blame] | 106 | freed += sb->s_op->free_cached_objects(sb, sc); |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 107 | } |
| 108 | |
Konstantin Khlebnikov | eb6ef3d | 2015-02-19 20:19:35 +0300 | [diff] [blame] | 109 | up_read(&sb->s_umount); |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 110 | return freed; |
| 111 | } |
| 112 | |
| 113 | static unsigned long super_cache_count(struct shrinker *shrink, |
| 114 | struct shrink_control *sc) |
| 115 | { |
| 116 | struct super_block *sb; |
| 117 | long total_objects = 0; |
| 118 | |
| 119 | sb = container_of(shrink, struct super_block, s_shrink); |
| 120 | |
Tim Chen | d23da15 | 2014-06-04 16:10:47 -0700 | [diff] [blame] | 121 | /* |
Konstantin Khlebnikov | eb6ef3d | 2015-02-19 20:19:35 +0300 | [diff] [blame] | 122 | * Don't call trylock_super as it is a potential |
Tim Chen | d23da15 | 2014-06-04 16:10:47 -0700 | [diff] [blame] | 123 | * scalability bottleneck. The counts could get updated |
| 124 | * between super_cache_count and super_cache_scan anyway. |
| 125 | * Call to super_cache_count with shrinker_rwsem held |
Vladimir Davydov | 503c358 | 2015-02-12 14:58:47 -0800 | [diff] [blame] | 126 | * ensures the safety of call to list_lru_shrink_count() and |
Tim Chen | d23da15 | 2014-06-04 16:10:47 -0700 | [diff] [blame] | 127 | * s_op->nr_cached_objects(). |
| 128 | */ |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 129 | if (sb->s_op && sb->s_op->nr_cached_objects) |
Vladimir Davydov | 4101b62 | 2015-02-12 14:58:51 -0800 | [diff] [blame] | 130 | total_objects = sb->s_op->nr_cached_objects(sb, sc); |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 131 | |
Vladimir Davydov | 503c358 | 2015-02-12 14:58:47 -0800 | [diff] [blame] | 132 | total_objects += list_lru_shrink_count(&sb->s_dentry_lru, sc); |
| 133 | total_objects += list_lru_shrink_count(&sb->s_inode_lru, sc); |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 134 | |
Glauber Costa | 55f841c | 2013-08-28 10:17:53 +1000 | [diff] [blame] | 135 | total_objects = vfs_pressure_ratio(total_objects); |
Dave Chinner | 0e1fdaf | 2011-07-08 14:14:44 +1000 | [diff] [blame] | 136 | return total_objects; |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 137 | } |
| 138 | |
Oleg Nesterov | 853b39a | 2015-07-22 20:21:13 +0200 | [diff] [blame] | 139 | static void destroy_super_work(struct work_struct *work) |
| 140 | { |
| 141 | struct super_block *s = container_of(work, struct super_block, |
| 142 | destroy_work); |
| 143 | int i; |
| 144 | |
| 145 | for (i = 0; i < SB_FREEZE_LEVELS; i++) |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 146 | percpu_free_rwsem(&s->s_writers.rw_sem[i]); |
Oleg Nesterov | 853b39a | 2015-07-22 20:21:13 +0200 | [diff] [blame] | 147 | kfree(s); |
| 148 | } |
| 149 | |
| 150 | static void destroy_super_rcu(struct rcu_head *head) |
| 151 | { |
| 152 | struct super_block *s = container_of(head, struct super_block, rcu); |
| 153 | INIT_WORK(&s->destroy_work, destroy_super_work); |
| 154 | schedule_work(&s->destroy_work); |
| 155 | } |
| 156 | |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 157 | /** |
| 158 | * destroy_super - frees a superblock |
| 159 | * @s: superblock to free |
| 160 | * |
| 161 | * Frees a superblock. |
| 162 | */ |
| 163 | static void destroy_super(struct super_block *s) |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 164 | { |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 165 | list_lru_destroy(&s->s_dentry_lru); |
| 166 | list_lru_destroy(&s->s_inode_lru); |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 167 | security_sb_free(s); |
| 168 | WARN_ON(!list_empty(&s->s_mounts)); |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 169 | put_user_ns(s->s_user_ns); |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 170 | kfree(s->s_subtype); |
Oleg Nesterov | 853b39a | 2015-07-22 20:21:13 +0200 | [diff] [blame] | 171 | call_rcu(&s->rcu, destroy_super_rcu); |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 172 | } |
| 173 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 174 | /** |
| 175 | * alloc_super - create new superblock |
Henrik Kretzschmar | fe2bbc4 | 2006-09-06 00:03:41 -0700 | [diff] [blame] | 176 | * @type: filesystem type superblock should belong to |
David Howells | 9249e17 | 2012-06-25 12:55:37 +0100 | [diff] [blame] | 177 | * @flags: the mount flags |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 178 | * @user_ns: User namespace for the super_block |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 | * |
| 180 | * Allocates and initializes a new &struct super_block. alloc_super() |
| 181 | * returns a pointer new superblock or %NULL if allocation had failed. |
| 182 | */ |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 183 | static struct super_block *alloc_super(struct file_system_type *type, int flags, |
| 184 | struct user_namespace *user_ns) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 185 | { |
Oliver Neukum | 11b0b5a | 2006-03-25 03:08:13 -0800 | [diff] [blame] | 186 | struct super_block *s = kzalloc(sizeof(struct super_block), GFP_USER); |
Alexey Dobriyan | b87221d | 2009-09-21 17:01:09 -0700 | [diff] [blame] | 187 | static const struct super_operations default_op; |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 188 | int i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 189 | |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 190 | if (!s) |
| 191 | return NULL; |
| 192 | |
Vladimir Davydov | b5bd856 | 2014-01-21 15:48:45 -0800 | [diff] [blame] | 193 | INIT_LIST_HEAD(&s->s_mounts); |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 194 | s->s_user_ns = get_user_ns(user_ns); |
Vladimir Davydov | b5bd856 | 2014-01-21 15:48:45 -0800 | [diff] [blame] | 195 | |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 196 | if (security_sb_alloc(s)) |
| 197 | goto fail; |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 198 | |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 199 | for (i = 0; i < SB_FREEZE_LEVELS; i++) { |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 200 | if (__percpu_init_rwsem(&s->s_writers.rw_sem[i], |
| 201 | sb_writers_name[i], |
| 202 | &type->s_writers_key[i])) |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 203 | goto fail; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | } |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 205 | init_waitqueue_head(&s->s_writers.wait_unfrozen); |
Christoph Hellwig | df0ce26 | 2015-01-14 10:42:41 +0100 | [diff] [blame] | 206 | s->s_bdi = &noop_backing_dev_info; |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 207 | s->s_flags = flags; |
Eric W. Biederman | cc50a07 | 2016-06-09 15:44:48 -0500 | [diff] [blame] | 208 | if (s->s_user_ns != &init_user_ns) |
Eric W. Biederman | 67690f9 | 2016-05-18 13:50:06 -0500 | [diff] [blame] | 209 | s->s_iflags |= SB_I_NODEV; |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 210 | INIT_HLIST_NODE(&s->s_instances); |
| 211 | INIT_HLIST_BL_HEAD(&s->s_anon); |
Dave Chinner | e97fedb | 2015-03-04 13:40:00 -0500 | [diff] [blame] | 212 | mutex_init(&s->s_sync_lock); |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 213 | INIT_LIST_HEAD(&s->s_inodes); |
Dave Chinner | 74278da9 | 2015-03-04 12:37:22 -0500 | [diff] [blame] | 214 | spin_lock_init(&s->s_inode_list_lock); |
Dave Chinner | 6c60d2b | 2016-07-26 15:21:50 -0700 | [diff] [blame] | 215 | INIT_LIST_HEAD(&s->s_inodes_wb); |
| 216 | spin_lock_init(&s->s_inode_wblist_lock); |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 217 | |
Vladimir Davydov | 2acb60a | 2015-02-12 14:59:14 -0800 | [diff] [blame] | 218 | if (list_lru_init_memcg(&s->s_dentry_lru)) |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 219 | goto fail; |
Vladimir Davydov | 2acb60a | 2015-02-12 14:59:14 -0800 | [diff] [blame] | 220 | if (list_lru_init_memcg(&s->s_inode_lru)) |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 221 | goto fail; |
| 222 | |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 223 | init_rwsem(&s->s_umount); |
| 224 | lockdep_set_class(&s->s_umount, &type->s_umount_key); |
| 225 | /* |
| 226 | * sget() can have s_umount recursion. |
| 227 | * |
| 228 | * When it cannot find a suitable sb, it allocates a new |
| 229 | * one (this one), and tries again to find a suitable old |
| 230 | * one. |
| 231 | * |
| 232 | * In case that succeeds, it will acquire the s_umount |
| 233 | * lock of the old one. Since these are clearly distrinct |
| 234 | * locks, and this object isn't exposed yet, there's no |
| 235 | * risk of deadlocks. |
| 236 | * |
| 237 | * Annotate this by putting this lock in a different |
| 238 | * subclass. |
| 239 | */ |
| 240 | down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING); |
| 241 | s->s_count = 1; |
| 242 | atomic_set(&s->s_active, 1); |
| 243 | mutex_init(&s->s_vfs_rename_mutex); |
| 244 | lockdep_set_class(&s->s_vfs_rename_mutex, &type->s_vfs_rename_key); |
Jan Kara | bc8230e | 2017-06-08 14:39:48 +0200 | [diff] [blame] | 245 | init_rwsem(&s->s_dquot.dqio_sem); |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 246 | s->s_maxbytes = MAX_NON_LFS; |
| 247 | s->s_op = &default_op; |
| 248 | s->s_time_gran = 1000000000; |
Vladimir Davydov | 3cb29d1 | 2015-04-14 15:46:48 -0700 | [diff] [blame] | 249 | s->cleancache_poolid = CLEANCACHE_NO_POOL; |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 250 | |
| 251 | s->s_shrink.seeks = DEFAULT_SEEKS; |
| 252 | s->s_shrink.scan_objects = super_cache_scan; |
| 253 | s->s_shrink.count_objects = super_cache_count; |
| 254 | s->s_shrink.batch = 1024; |
Vladimir Davydov | 2acb60a | 2015-02-12 14:59:14 -0800 | [diff] [blame] | 255 | s->s_shrink.flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 256 | return s; |
Glauber Costa | 5ca302c | 2013-08-28 10:18:18 +1000 | [diff] [blame] | 257 | |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 258 | fail: |
| 259 | destroy_super(s); |
| 260 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 261 | } |
| 262 | |
| 263 | /* Superblock refcounting */ |
| 264 | |
| 265 | /* |
Al Viro | 35cf7ba | 2010-03-22 21:13:53 -0400 | [diff] [blame] | 266 | * Drop a superblock's refcount. The caller must hold sb_lock. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 267 | */ |
Al Viro | f47ec3f2 | 2011-11-21 21:15:42 -0500 | [diff] [blame] | 268 | static void __put_super(struct super_block *sb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 269 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 270 | if (!--sb->s_count) { |
Al Viro | 551de6f | 2010-03-22 19:36:35 -0400 | [diff] [blame] | 271 | list_del_init(&sb->s_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 272 | destroy_super(sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 273 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 274 | } |
| 275 | |
| 276 | /** |
| 277 | * put_super - drop a temporary reference to superblock |
| 278 | * @sb: superblock in question |
| 279 | * |
| 280 | * Drops a temporary reference, frees superblock if there's no |
| 281 | * references left. |
| 282 | */ |
Al Viro | f47ec3f2 | 2011-11-21 21:15:42 -0500 | [diff] [blame] | 283 | static void put_super(struct super_block *sb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 284 | { |
| 285 | spin_lock(&sb_lock); |
| 286 | __put_super(sb); |
| 287 | spin_unlock(&sb_lock); |
| 288 | } |
| 289 | |
| 290 | |
| 291 | /** |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 292 | * deactivate_locked_super - drop an active reference to superblock |
| 293 | * @s: superblock to deactivate |
| 294 | * |
Masanari Iida | bd7ced9 | 2016-02-02 22:31:06 +0900 | [diff] [blame] | 295 | * Drops an active reference to superblock, converting it into a temporary |
Al Viro | 1712ac8 | 2010-03-22 15:22:31 -0400 | [diff] [blame] | 296 | * one if there is no other active references left. In that case we |
| 297 | * tell fs driver to shut it down and drop the temporary reference we |
| 298 | * had just acquired. |
| 299 | * |
| 300 | * Caller holds exclusive lock on superblock; that lock is released. |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 301 | */ |
| 302 | void deactivate_locked_super(struct super_block *s) |
| 303 | { |
| 304 | struct file_system_type *fs = s->s_type; |
Al Viro | b20bd1a | 2010-03-22 08:53:19 -0400 | [diff] [blame] | 305 | if (atomic_dec_and_test(&s->s_active)) { |
Dan Magenheimer | 3167760 | 2011-09-21 11:56:28 -0400 | [diff] [blame] | 306 | cleancache_invalidate_fs(s); |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 307 | unregister_shrinker(&s->s_shrink); |
Dave Chinner | 28f2cd4f | 2014-06-04 16:10:46 -0700 | [diff] [blame] | 308 | fs->kill_sb(s); |
Glauber Costa | f5e1dd3 | 2013-08-28 10:18:18 +1000 | [diff] [blame] | 309 | |
Vladimir Davydov | c0a5b56 | 2015-02-12 14:59:07 -0800 | [diff] [blame] | 310 | /* |
| 311 | * Since list_lru_destroy() may sleep, we cannot call it from |
| 312 | * put_super(), where we hold the sb_lock. Therefore we destroy |
| 313 | * the lru lists right now. |
| 314 | */ |
| 315 | list_lru_destroy(&s->s_dentry_lru); |
| 316 | list_lru_destroy(&s->s_inode_lru); |
| 317 | |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 318 | put_filesystem(fs); |
| 319 | put_super(s); |
| 320 | } else { |
| 321 | up_write(&s->s_umount); |
| 322 | } |
| 323 | } |
| 324 | |
| 325 | EXPORT_SYMBOL(deactivate_locked_super); |
| 326 | |
| 327 | /** |
Al Viro | 1712ac8 | 2010-03-22 15:22:31 -0400 | [diff] [blame] | 328 | * deactivate_super - drop an active reference to superblock |
| 329 | * @s: superblock to deactivate |
| 330 | * |
| 331 | * Variant of deactivate_locked_super(), except that superblock is *not* |
| 332 | * locked by caller. If we are going to drop the final active reference, |
| 333 | * lock will be acquired prior to that. |
| 334 | */ |
| 335 | void deactivate_super(struct super_block *s) |
| 336 | { |
| 337 | if (!atomic_add_unless(&s->s_active, -1, 1)) { |
| 338 | down_write(&s->s_umount); |
| 339 | deactivate_locked_super(s); |
| 340 | } |
| 341 | } |
| 342 | |
| 343 | EXPORT_SYMBOL(deactivate_super); |
| 344 | |
| 345 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 346 | * grab_super - acquire an active reference |
| 347 | * @s: reference we are trying to make active |
| 348 | * |
| 349 | * Tries to acquire an active reference. grab_super() is used when we |
| 350 | * had just found a superblock in super_blocks or fs_type->fs_supers |
| 351 | * and want to turn it into a full-blown active reference. grab_super() |
| 352 | * is called with sb_lock held and drops it. Returns 1 in case of |
| 353 | * success, 0 if we had failed (superblock contents was already dead or |
Al Viro | acfec9a | 2013-07-20 03:13:55 +0400 | [diff] [blame] | 354 | * dying when grab_super() had been called). Note that this is only |
| 355 | * called for superblocks not in rundown mode (== ones still on ->fs_supers |
| 356 | * of their type), so increment of ->s_count is OK here. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 357 | */ |
Josh Triplett | 9c4dbee | 2006-09-29 01:59:29 -0700 | [diff] [blame] | 358 | static int grab_super(struct super_block *s) __releases(sb_lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 359 | { |
| 360 | s->s_count++; |
| 361 | spin_unlock(&sb_lock); |
| 362 | down_write(&s->s_umount); |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 363 | if ((s->s_flags & SB_BORN) && atomic_inc_not_zero(&s->s_active)) { |
Al Viro | acfec9a | 2013-07-20 03:13:55 +0400 | [diff] [blame] | 364 | put_super(s); |
| 365 | return 1; |
| 366 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 367 | up_write(&s->s_umount); |
| 368 | put_super(s); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 369 | return 0; |
| 370 | } |
| 371 | |
David Howells | cf9a2ae | 2006-08-29 19:05:54 +0100 | [diff] [blame] | 372 | /* |
Konstantin Khlebnikov | eb6ef3d | 2015-02-19 20:19:35 +0300 | [diff] [blame] | 373 | * trylock_super - try to grab ->s_umount shared |
Wanpeng Li | 331cbde | 2012-06-09 11:10:55 +0800 | [diff] [blame] | 374 | * @sb: reference we are trying to grab |
Dave Chinner | 12ad3ab | 2011-07-08 14:14:41 +1000 | [diff] [blame] | 375 | * |
Konstantin Khlebnikov | eb6ef3d | 2015-02-19 20:19:35 +0300 | [diff] [blame] | 376 | * Try to prevent fs shutdown. This is used in places where we |
Dave Chinner | 12ad3ab | 2011-07-08 14:14:41 +1000 | [diff] [blame] | 377 | * cannot take an active reference but we need to ensure that the |
Konstantin Khlebnikov | eb6ef3d | 2015-02-19 20:19:35 +0300 | [diff] [blame] | 378 | * filesystem is not shut down while we are working on it. It returns |
| 379 | * false if we cannot acquire s_umount or if we lose the race and |
| 380 | * filesystem already got into shutdown, and returns true with the s_umount |
| 381 | * lock held in read mode in case of success. On successful return, |
| 382 | * the caller must drop the s_umount lock when done. |
| 383 | * |
| 384 | * Note that unlike get_super() et.al. this one does *not* bump ->s_count. |
| 385 | * The reason why it's safe is that we are OK with doing trylock instead |
| 386 | * of down_read(). There's a couple of places that are OK with that, but |
| 387 | * it's very much not a general-purpose interface. |
Dave Chinner | 12ad3ab | 2011-07-08 14:14:41 +1000 | [diff] [blame] | 388 | */ |
Konstantin Khlebnikov | eb6ef3d | 2015-02-19 20:19:35 +0300 | [diff] [blame] | 389 | bool trylock_super(struct super_block *sb) |
Dave Chinner | 12ad3ab | 2011-07-08 14:14:41 +1000 | [diff] [blame] | 390 | { |
Dave Chinner | 12ad3ab | 2011-07-08 14:14:41 +1000 | [diff] [blame] | 391 | if (down_read_trylock(&sb->s_umount)) { |
Konstantin Khlebnikov | eb6ef3d | 2015-02-19 20:19:35 +0300 | [diff] [blame] | 392 | if (!hlist_unhashed(&sb->s_instances) && |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 393 | sb->s_root && (sb->s_flags & SB_BORN)) |
Dave Chinner | 12ad3ab | 2011-07-08 14:14:41 +1000 | [diff] [blame] | 394 | return true; |
| 395 | up_read(&sb->s_umount); |
| 396 | } |
| 397 | |
Dave Chinner | 12ad3ab | 2011-07-08 14:14:41 +1000 | [diff] [blame] | 398 | return false; |
| 399 | } |
| 400 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 401 | /** |
| 402 | * generic_shutdown_super - common helper for ->kill_sb() |
| 403 | * @sb: superblock to kill |
| 404 | * |
| 405 | * generic_shutdown_super() does all fs-independent work on superblock |
| 406 | * shutdown. Typical ->kill_sb() should pick all fs-specific objects |
| 407 | * that need destruction out of superblock, call generic_shutdown_super() |
| 408 | * and release aforementioned objects. Note: dentries and inodes _are_ |
| 409 | * taken care of and do not need specific handling. |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 410 | * |
| 411 | * Upon calling this function, the filesystem may no longer alter or |
| 412 | * rearrange the set of dentries belonging to this super_block, nor may it |
| 413 | * change the attachments of dentries to inodes. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 414 | */ |
| 415 | void generic_shutdown_super(struct super_block *sb) |
| 416 | { |
Josef 'Jeff' Sipek | ee9b6d6 | 2007-02-12 00:55:41 -0800 | [diff] [blame] | 417 | const struct super_operations *sop = sb->s_op; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 418 | |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 419 | if (sb->s_root) { |
| 420 | shrink_dcache_for_umount(sb); |
Jan Kara | 60b0680 | 2009-04-27 16:43:53 +0200 | [diff] [blame] | 421 | sync_filesystem(sb); |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 422 | sb->s_flags &= ~SB_ACTIVE; |
Arjan van de Ven | efaee19 | 2009-01-06 07:20:54 -0800 | [diff] [blame] | 423 | |
Dave Chinner | 74278da9 | 2015-03-04 12:37:22 -0500 | [diff] [blame] | 424 | fsnotify_unmount_inodes(sb); |
Tejun Heo | a1a0e23 | 2016-02-29 18:28:53 -0500 | [diff] [blame] | 425 | cgroup_writeback_umount(); |
Al Viro | 63997e9 | 2010-10-25 20:49:35 -0400 | [diff] [blame] | 426 | |
| 427 | evict_inodes(sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 428 | |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 429 | if (sb->s_dio_done_wq) { |
| 430 | destroy_workqueue(sb->s_dio_done_wq); |
| 431 | sb->s_dio_done_wq = NULL; |
| 432 | } |
| 433 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 434 | if (sop->put_super) |
| 435 | sop->put_super(sb); |
| 436 | |
Al Viro | 63997e9 | 2010-10-25 20:49:35 -0400 | [diff] [blame] | 437 | if (!list_empty(&sb->s_inodes)) { |
Dave Jones | 7b4fe29 | 2006-02-07 12:58:48 -0800 | [diff] [blame] | 438 | printk("VFS: Busy inodes after unmount of %s. " |
| 439 | "Self-destruct in 5 seconds. Have a nice day...\n", |
| 440 | sb->s_id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 441 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 442 | } |
| 443 | spin_lock(&sb_lock); |
| 444 | /* should be initialized for __put_super_and_need_restart() */ |
Al Viro | a516616 | 2011-12-12 22:53:00 -0500 | [diff] [blame] | 445 | hlist_del_init(&sb->s_instances); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 446 | spin_unlock(&sb_lock); |
| 447 | up_write(&sb->s_umount); |
Jan Kara | c1844d5 | 2017-04-12 12:24:47 +0200 | [diff] [blame] | 448 | if (sb->s_bdi != &noop_backing_dev_info) { |
Jan Kara | fca3934 | 2017-04-12 12:24:28 +0200 | [diff] [blame] | 449 | bdi_put(sb->s_bdi); |
| 450 | sb->s_bdi = &noop_backing_dev_info; |
Jan Kara | fca3934 | 2017-04-12 12:24:28 +0200 | [diff] [blame] | 451 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 452 | } |
| 453 | |
| 454 | EXPORT_SYMBOL(generic_shutdown_super); |
| 455 | |
| 456 | /** |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 457 | * sget_userns - find or create a superblock |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 458 | * @type: filesystem type superblock should belong to |
| 459 | * @test: comparison callback |
| 460 | * @set: setup callback |
David Howells | 9249e17 | 2012-06-25 12:55:37 +0100 | [diff] [blame] | 461 | * @flags: mount flags |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 462 | * @user_ns: User namespace for the super_block |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 463 | * @data: argument to each of them |
| 464 | */ |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 465 | struct super_block *sget_userns(struct file_system_type *type, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 466 | int (*test)(struct super_block *,void *), |
| 467 | int (*set)(struct super_block *,void *), |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 468 | int flags, struct user_namespace *user_ns, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 469 | void *data) |
| 470 | { |
| 471 | struct super_block *s = NULL; |
Matthias Kaehlcke | d473012 | 2007-10-18 23:39:57 -0700 | [diff] [blame] | 472 | struct super_block *old; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 473 | int err; |
| 474 | |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 475 | if (!(flags & (SB_KERNMOUNT|SB_SUBMOUNT)) && |
Eric W. Biederman | a001e74 | 2016-06-06 15:48:04 -0500 | [diff] [blame] | 476 | !(type->fs_flags & FS_USERNS_MOUNT) && |
| 477 | !capable(CAP_SYS_ADMIN)) |
| 478 | return ERR_PTR(-EPERM); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 479 | retry: |
| 480 | spin_lock(&sb_lock); |
Matthias Kaehlcke | d473012 | 2007-10-18 23:39:57 -0700 | [diff] [blame] | 481 | if (test) { |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 482 | hlist_for_each_entry(old, &type->fs_supers, s_instances) { |
Matthias Kaehlcke | d473012 | 2007-10-18 23:39:57 -0700 | [diff] [blame] | 483 | if (!test(old, data)) |
| 484 | continue; |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 485 | if (user_ns != old->s_user_ns) { |
| 486 | spin_unlock(&sb_lock); |
| 487 | if (s) { |
| 488 | up_write(&s->s_umount); |
| 489 | destroy_super(s); |
| 490 | } |
| 491 | return ERR_PTR(-EBUSY); |
| 492 | } |
Matthias Kaehlcke | d473012 | 2007-10-18 23:39:57 -0700 | [diff] [blame] | 493 | if (!grab_super(old)) |
| 494 | goto retry; |
Li Zefan | a3cfbb5 | 2009-03-12 14:31:29 -0700 | [diff] [blame] | 495 | if (s) { |
| 496 | up_write(&s->s_umount); |
Matthias Kaehlcke | d473012 | 2007-10-18 23:39:57 -0700 | [diff] [blame] | 497 | destroy_super(s); |
Al Viro | 7a4dec5 | 2010-08-09 12:05:43 -0400 | [diff] [blame] | 498 | s = NULL; |
Li Zefan | a3cfbb5 | 2009-03-12 14:31:29 -0700 | [diff] [blame] | 499 | } |
Matthias Kaehlcke | d473012 | 2007-10-18 23:39:57 -0700 | [diff] [blame] | 500 | return old; |
| 501 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 502 | } |
| 503 | if (!s) { |
| 504 | spin_unlock(&sb_lock); |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 505 | s = alloc_super(type, (flags & ~SB_SUBMOUNT), user_ns); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 506 | if (!s) |
| 507 | return ERR_PTR(-ENOMEM); |
| 508 | goto retry; |
| 509 | } |
David Howells | dd111b3 | 2017-07-04 17:25:09 +0100 | [diff] [blame] | 510 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 511 | err = set(s, data); |
| 512 | if (err) { |
| 513 | spin_unlock(&sb_lock); |
Li Zefan | a3cfbb5 | 2009-03-12 14:31:29 -0700 | [diff] [blame] | 514 | up_write(&s->s_umount); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 515 | destroy_super(s); |
| 516 | return ERR_PTR(err); |
| 517 | } |
| 518 | s->s_type = type; |
| 519 | strlcpy(s->s_id, type->name, sizeof(s->s_id)); |
| 520 | list_add_tail(&s->s_list, &super_blocks); |
Al Viro | a516616 | 2011-12-12 22:53:00 -0500 | [diff] [blame] | 521 | hlist_add_head(&s->s_instances, &type->fs_supers); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 522 | spin_unlock(&sb_lock); |
| 523 | get_filesystem(type); |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 524 | register_shrinker(&s->s_shrink); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 525 | return s; |
| 526 | } |
| 527 | |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 528 | EXPORT_SYMBOL(sget_userns); |
| 529 | |
| 530 | /** |
| 531 | * sget - find or create a superblock |
| 532 | * @type: filesystem type superblock should belong to |
| 533 | * @test: comparison callback |
| 534 | * @set: setup callback |
| 535 | * @flags: mount flags |
| 536 | * @data: argument to each of them |
| 537 | */ |
| 538 | struct super_block *sget(struct file_system_type *type, |
| 539 | int (*test)(struct super_block *,void *), |
| 540 | int (*set)(struct super_block *,void *), |
| 541 | int flags, |
| 542 | void *data) |
| 543 | { |
| 544 | struct user_namespace *user_ns = current_user_ns(); |
| 545 | |
Eric W. Biederman | 93faccbb | 2017-02-01 06:06:16 +1300 | [diff] [blame] | 546 | /* We don't yet pass the user namespace of the parent |
| 547 | * mount through to here so always use &init_user_ns |
| 548 | * until that changes. |
| 549 | */ |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 550 | if (flags & SB_SUBMOUNT) |
Eric W. Biederman | 93faccbb | 2017-02-01 06:06:16 +1300 | [diff] [blame] | 551 | user_ns = &init_user_ns; |
| 552 | |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 553 | /* Ensure the requestor has permissions over the target filesystem */ |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 554 | if (!(flags & (SB_KERNMOUNT|SB_SUBMOUNT)) && !ns_capable(user_ns, CAP_SYS_ADMIN)) |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 555 | return ERR_PTR(-EPERM); |
| 556 | |
| 557 | return sget_userns(type, test, set, flags, user_ns, data); |
| 558 | } |
| 559 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 560 | EXPORT_SYMBOL(sget); |
| 561 | |
| 562 | void drop_super(struct super_block *sb) |
| 563 | { |
| 564 | up_read(&sb->s_umount); |
| 565 | put_super(sb); |
| 566 | } |
| 567 | |
| 568 | EXPORT_SYMBOL(drop_super); |
| 569 | |
Jan Kara | ba6379f | 2016-11-23 12:53:00 +0100 | [diff] [blame] | 570 | void drop_super_exclusive(struct super_block *sb) |
| 571 | { |
| 572 | up_write(&sb->s_umount); |
| 573 | put_super(sb); |
| 574 | } |
| 575 | EXPORT_SYMBOL(drop_super_exclusive); |
| 576 | |
Christoph Hellwig | e500475 | 2009-05-05 16:08:56 +0200 | [diff] [blame] | 577 | /** |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 578 | * iterate_supers - call function for all active superblocks |
| 579 | * @f: function to call |
| 580 | * @arg: argument to pass to it |
| 581 | * |
| 582 | * Scans the superblock list and calls given function, passing it |
| 583 | * locked superblock and given argument. |
| 584 | */ |
| 585 | void iterate_supers(void (*f)(struct super_block *, void *), void *arg) |
| 586 | { |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 587 | struct super_block *sb, *p = NULL; |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 588 | |
| 589 | spin_lock(&sb_lock); |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 590 | list_for_each_entry(sb, &super_blocks, s_list) { |
Al Viro | a516616 | 2011-12-12 22:53:00 -0500 | [diff] [blame] | 591 | if (hlist_unhashed(&sb->s_instances)) |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 592 | continue; |
| 593 | sb->s_count++; |
| 594 | spin_unlock(&sb_lock); |
| 595 | |
| 596 | down_read(&sb->s_umount); |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 597 | if (sb->s_root && (sb->s_flags & SB_BORN)) |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 598 | f(sb, arg); |
| 599 | up_read(&sb->s_umount); |
| 600 | |
| 601 | spin_lock(&sb_lock); |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 602 | if (p) |
| 603 | __put_super(p); |
| 604 | p = sb; |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 605 | } |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 606 | if (p) |
| 607 | __put_super(p); |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 608 | spin_unlock(&sb_lock); |
| 609 | } |
| 610 | |
| 611 | /** |
Al Viro | 43e15cd | 2011-06-03 20:16:57 -0400 | [diff] [blame] | 612 | * iterate_supers_type - call function for superblocks of given type |
| 613 | * @type: fs type |
| 614 | * @f: function to call |
| 615 | * @arg: argument to pass to it |
| 616 | * |
| 617 | * Scans the superblock list and calls given function, passing it |
| 618 | * locked superblock and given argument. |
| 619 | */ |
| 620 | void iterate_supers_type(struct file_system_type *type, |
| 621 | void (*f)(struct super_block *, void *), void *arg) |
| 622 | { |
| 623 | struct super_block *sb, *p = NULL; |
| 624 | |
| 625 | spin_lock(&sb_lock); |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 626 | hlist_for_each_entry(sb, &type->fs_supers, s_instances) { |
Al Viro | 43e15cd | 2011-06-03 20:16:57 -0400 | [diff] [blame] | 627 | sb->s_count++; |
| 628 | spin_unlock(&sb_lock); |
| 629 | |
| 630 | down_read(&sb->s_umount); |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 631 | if (sb->s_root && (sb->s_flags & SB_BORN)) |
Al Viro | 43e15cd | 2011-06-03 20:16:57 -0400 | [diff] [blame] | 632 | f(sb, arg); |
| 633 | up_read(&sb->s_umount); |
| 634 | |
| 635 | spin_lock(&sb_lock); |
| 636 | if (p) |
| 637 | __put_super(p); |
| 638 | p = sb; |
| 639 | } |
| 640 | if (p) |
| 641 | __put_super(p); |
| 642 | spin_unlock(&sb_lock); |
| 643 | } |
| 644 | |
| 645 | EXPORT_SYMBOL(iterate_supers_type); |
| 646 | |
Jan Kara | ba6379f | 2016-11-23 12:53:00 +0100 | [diff] [blame] | 647 | static struct super_block *__get_super(struct block_device *bdev, bool excl) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 648 | { |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 649 | struct super_block *sb; |
| 650 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 651 | if (!bdev) |
| 652 | return NULL; |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 653 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 654 | spin_lock(&sb_lock); |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 655 | rescan: |
| 656 | list_for_each_entry(sb, &super_blocks, s_list) { |
Al Viro | a516616 | 2011-12-12 22:53:00 -0500 | [diff] [blame] | 657 | if (hlist_unhashed(&sb->s_instances)) |
Al Viro | 551de6f | 2010-03-22 19:36:35 -0400 | [diff] [blame] | 658 | continue; |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 659 | if (sb->s_bdev == bdev) { |
| 660 | sb->s_count++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 661 | spin_unlock(&sb_lock); |
Jan Kara | ba6379f | 2016-11-23 12:53:00 +0100 | [diff] [blame] | 662 | if (!excl) |
| 663 | down_read(&sb->s_umount); |
| 664 | else |
| 665 | down_write(&sb->s_umount); |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 666 | /* still alive? */ |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 667 | if (sb->s_root && (sb->s_flags & SB_BORN)) |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 668 | return sb; |
Jan Kara | ba6379f | 2016-11-23 12:53:00 +0100 | [diff] [blame] | 669 | if (!excl) |
| 670 | up_read(&sb->s_umount); |
| 671 | else |
| 672 | up_write(&sb->s_umount); |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 673 | /* nope, got unmounted */ |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 674 | spin_lock(&sb_lock); |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 675 | __put_super(sb); |
| 676 | goto rescan; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 677 | } |
| 678 | } |
| 679 | spin_unlock(&sb_lock); |
| 680 | return NULL; |
| 681 | } |
| 682 | |
Jan Kara | ba6379f | 2016-11-23 12:53:00 +0100 | [diff] [blame] | 683 | /** |
| 684 | * get_super - get the superblock of a device |
| 685 | * @bdev: device to get the superblock for |
| 686 | * |
| 687 | * Scans the superblock list and finds the superblock of the file system |
| 688 | * mounted on the device given. %NULL is returned if no match is found. |
| 689 | */ |
| 690 | struct super_block *get_super(struct block_device *bdev) |
| 691 | { |
| 692 | return __get_super(bdev, false); |
| 693 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 694 | EXPORT_SYMBOL(get_super); |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 695 | |
Jan Kara | ba6379f | 2016-11-23 12:53:00 +0100 | [diff] [blame] | 696 | static struct super_block *__get_super_thawed(struct block_device *bdev, |
| 697 | bool excl) |
| 698 | { |
| 699 | while (1) { |
| 700 | struct super_block *s = __get_super(bdev, excl); |
| 701 | if (!s || s->s_writers.frozen == SB_UNFROZEN) |
| 702 | return s; |
| 703 | if (!excl) |
| 704 | up_read(&s->s_umount); |
| 705 | else |
| 706 | up_write(&s->s_umount); |
| 707 | wait_event(s->s_writers.wait_unfrozen, |
| 708 | s->s_writers.frozen == SB_UNFROZEN); |
| 709 | put_super(s); |
| 710 | } |
| 711 | } |
| 712 | |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 713 | /** |
Jan Kara | 6b6dc83 | 2012-02-10 11:03:00 +0100 | [diff] [blame] | 714 | * get_super_thawed - get thawed superblock of a device |
| 715 | * @bdev: device to get the superblock for |
| 716 | * |
| 717 | * Scans the superblock list and finds the superblock of the file system |
| 718 | * mounted on the device. The superblock is returned once it is thawed |
| 719 | * (or immediately if it was not frozen). %NULL is returned if no match |
| 720 | * is found. |
| 721 | */ |
| 722 | struct super_block *get_super_thawed(struct block_device *bdev) |
| 723 | { |
Jan Kara | ba6379f | 2016-11-23 12:53:00 +0100 | [diff] [blame] | 724 | return __get_super_thawed(bdev, false); |
Jan Kara | 6b6dc83 | 2012-02-10 11:03:00 +0100 | [diff] [blame] | 725 | } |
| 726 | EXPORT_SYMBOL(get_super_thawed); |
| 727 | |
| 728 | /** |
Jan Kara | ba6379f | 2016-11-23 12:53:00 +0100 | [diff] [blame] | 729 | * get_super_exclusive_thawed - get thawed superblock of a device |
| 730 | * @bdev: device to get the superblock for |
| 731 | * |
| 732 | * Scans the superblock list and finds the superblock of the file system |
| 733 | * mounted on the device. The superblock is returned once it is thawed |
| 734 | * (or immediately if it was not frozen) and s_umount semaphore is held |
| 735 | * in exclusive mode. %NULL is returned if no match is found. |
| 736 | */ |
| 737 | struct super_block *get_super_exclusive_thawed(struct block_device *bdev) |
| 738 | { |
| 739 | return __get_super_thawed(bdev, true); |
| 740 | } |
| 741 | EXPORT_SYMBOL(get_super_exclusive_thawed); |
| 742 | |
| 743 | /** |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 744 | * get_active_super - get an active reference to the superblock of a device |
| 745 | * @bdev: device to get the superblock for |
| 746 | * |
| 747 | * Scans the superblock list and finds the superblock of the file system |
| 748 | * mounted on the device given. Returns the superblock with an active |
Al Viro | d3f2147 | 2010-03-23 11:11:05 -0400 | [diff] [blame] | 749 | * reference or %NULL if none was found. |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 750 | */ |
| 751 | struct super_block *get_active_super(struct block_device *bdev) |
| 752 | { |
| 753 | struct super_block *sb; |
| 754 | |
| 755 | if (!bdev) |
| 756 | return NULL; |
| 757 | |
Al Viro | 1494583 | 2010-03-22 20:15:33 -0400 | [diff] [blame] | 758 | restart: |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 759 | spin_lock(&sb_lock); |
| 760 | list_for_each_entry(sb, &super_blocks, s_list) { |
Al Viro | a516616 | 2011-12-12 22:53:00 -0500 | [diff] [blame] | 761 | if (hlist_unhashed(&sb->s_instances)) |
Al Viro | 551de6f | 2010-03-22 19:36:35 -0400 | [diff] [blame] | 762 | continue; |
Al Viro | 1494583 | 2010-03-22 20:15:33 -0400 | [diff] [blame] | 763 | if (sb->s_bdev == bdev) { |
Al Viro | acfec9a | 2013-07-20 03:13:55 +0400 | [diff] [blame] | 764 | if (!grab_super(sb)) |
Al Viro | 1494583 | 2010-03-22 20:15:33 -0400 | [diff] [blame] | 765 | goto restart; |
Al Viro | acfec9a | 2013-07-20 03:13:55 +0400 | [diff] [blame] | 766 | up_write(&sb->s_umount); |
| 767 | return sb; |
Al Viro | 1494583 | 2010-03-22 20:15:33 -0400 | [diff] [blame] | 768 | } |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 769 | } |
| 770 | spin_unlock(&sb_lock); |
| 771 | return NULL; |
| 772 | } |
David Howells | dd111b3 | 2017-07-04 17:25:09 +0100 | [diff] [blame] | 773 | |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 774 | struct super_block *user_get_super(dev_t dev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 775 | { |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 776 | struct super_block *sb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 777 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 778 | spin_lock(&sb_lock); |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 779 | rescan: |
| 780 | list_for_each_entry(sb, &super_blocks, s_list) { |
Al Viro | a516616 | 2011-12-12 22:53:00 -0500 | [diff] [blame] | 781 | if (hlist_unhashed(&sb->s_instances)) |
Al Viro | 551de6f | 2010-03-22 19:36:35 -0400 | [diff] [blame] | 782 | continue; |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 783 | if (sb->s_dev == dev) { |
| 784 | sb->s_count++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 785 | spin_unlock(&sb_lock); |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 786 | down_read(&sb->s_umount); |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 787 | /* still alive? */ |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 788 | if (sb->s_root && (sb->s_flags & SB_BORN)) |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 789 | return sb; |
| 790 | up_read(&sb->s_umount); |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 791 | /* nope, got unmounted */ |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 792 | spin_lock(&sb_lock); |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 793 | __put_super(sb); |
| 794 | goto rescan; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 795 | } |
| 796 | } |
| 797 | spin_unlock(&sb_lock); |
| 798 | return NULL; |
| 799 | } |
| 800 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 801 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 802 | * do_remount_sb - asks filesystem to change mount options. |
| 803 | * @sb: superblock in question |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 804 | * @sb_flags: revised superblock flags |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 805 | * @data: the rest of options |
| 806 | * @force: whether or not to force the change |
| 807 | * |
| 808 | * Alters the mount options of a mounted file system. |
| 809 | */ |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 810 | int do_remount_sb(struct super_block *sb, int sb_flags, void *data, int force) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 811 | { |
| 812 | int retval; |
Christoph Hellwig | c79d967 | 2010-05-19 07:16:40 -0400 | [diff] [blame] | 813 | int remount_ro; |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 814 | |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 815 | if (sb->s_writers.frozen != SB_UNFROZEN) |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 816 | return -EBUSY; |
| 817 | |
David Howells | 9361401 | 2006-09-30 20:45:40 +0200 | [diff] [blame] | 818 | #ifdef CONFIG_BLOCK |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 819 | if (!(sb_flags & SB_RDONLY) && bdev_read_only(sb->s_bdev)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 820 | return -EACCES; |
David Howells | 9361401 | 2006-09-30 20:45:40 +0200 | [diff] [blame] | 821 | #endif |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 822 | |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 823 | remount_ro = (sb_flags & SB_RDONLY) && !sb_rdonly(sb); |
Nick Piggin | d208bbd | 2009-12-21 16:28:53 -0800 | [diff] [blame] | 824 | |
Al Viro | 0aec09d | 2014-08-07 07:32:06 -0400 | [diff] [blame] | 825 | if (remount_ro) { |
Al Viro | fdab684 | 2015-01-11 10:57:27 -0500 | [diff] [blame] | 826 | if (!hlist_empty(&sb->s_pins)) { |
Al Viro | 0aec09d | 2014-08-07 07:32:06 -0400 | [diff] [blame] | 827 | up_write(&sb->s_umount); |
Al Viro | fdab684 | 2015-01-11 10:57:27 -0500 | [diff] [blame] | 828 | group_pin_kill(&sb->s_pins); |
Al Viro | 0aec09d | 2014-08-07 07:32:06 -0400 | [diff] [blame] | 829 | down_write(&sb->s_umount); |
| 830 | if (!sb->s_root) |
| 831 | return 0; |
| 832 | if (sb->s_writers.frozen != SB_UNFROZEN) |
| 833 | return -EBUSY; |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 834 | remount_ro = (sb_flags & SB_RDONLY) && !sb_rdonly(sb); |
Al Viro | 0aec09d | 2014-08-07 07:32:06 -0400 | [diff] [blame] | 835 | } |
| 836 | } |
| 837 | shrink_dcache_sb(sb); |
| 838 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 839 | /* If we are remounting RDONLY and current sb is read/write, |
| 840 | make sure there are no rw files opened */ |
Nick Piggin | d208bbd | 2009-12-21 16:28:53 -0800 | [diff] [blame] | 841 | if (remount_ro) { |
Miklos Szeredi | 4ed5e82f | 2011-11-21 12:11:31 +0100 | [diff] [blame] | 842 | if (force) { |
Al Viro | eee5cc2 | 2013-10-04 11:06:42 -0400 | [diff] [blame] | 843 | sb->s_readonly_remount = 1; |
| 844 | smp_wmb(); |
Miklos Szeredi | 4ed5e82f | 2011-11-21 12:11:31 +0100 | [diff] [blame] | 845 | } else { |
| 846 | retval = sb_prepare_remount_readonly(sb); |
| 847 | if (retval) |
| 848 | return retval; |
Miklos Szeredi | 4ed5e82f | 2011-11-21 12:11:31 +0100 | [diff] [blame] | 849 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 850 | } |
| 851 | |
| 852 | if (sb->s_op->remount_fs) { |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 853 | retval = sb->s_op->remount_fs(sb, &sb_flags, data); |
Miklos Szeredi | 2833eb2 | 2011-10-28 14:13:20 +0200 | [diff] [blame] | 854 | if (retval) { |
| 855 | if (!force) |
Miklos Szeredi | 4ed5e82f | 2011-11-21 12:11:31 +0100 | [diff] [blame] | 856 | goto cancel_readonly; |
Miklos Szeredi | 2833eb2 | 2011-10-28 14:13:20 +0200 | [diff] [blame] | 857 | /* If forced remount, go ahead despite any errors */ |
| 858 | WARN(1, "forced remount of a %s fs returned %i\n", |
| 859 | sb->s_type->name, retval); |
| 860 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 861 | } |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 862 | sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (sb_flags & MS_RMT_MASK); |
Miklos Szeredi | 4ed5e82f | 2011-11-21 12:11:31 +0100 | [diff] [blame] | 863 | /* Needs to be ordered wrt mnt_is_readonly() */ |
| 864 | smp_wmb(); |
| 865 | sb->s_readonly_remount = 0; |
Christoph Hellwig | c79d967 | 2010-05-19 07:16:40 -0400 | [diff] [blame] | 866 | |
Nick Piggin | d208bbd | 2009-12-21 16:28:53 -0800 | [diff] [blame] | 867 | /* |
| 868 | * Some filesystems modify their metadata via some other path than the |
| 869 | * bdev buffer cache (eg. use a private mapping, or directories in |
| 870 | * pagecache, etc). Also file data modifications go via their own |
| 871 | * mappings. So If we try to mount readonly then copy the filesystem |
| 872 | * from bdev, we could get stale data, so invalidate it to give a best |
| 873 | * effort at coherency. |
| 874 | */ |
| 875 | if (remount_ro && sb->s_bdev) |
| 876 | invalidate_bdev(sb->s_bdev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 877 | return 0; |
Miklos Szeredi | 4ed5e82f | 2011-11-21 12:11:31 +0100 | [diff] [blame] | 878 | |
| 879 | cancel_readonly: |
| 880 | sb->s_readonly_remount = 0; |
| 881 | return retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 882 | } |
| 883 | |
Jens Axboe | a2a9537 | 2009-03-17 09:38:40 +0100 | [diff] [blame] | 884 | static void do_emergency_remount(struct work_struct *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 885 | { |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 886 | struct super_block *sb, *p = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 887 | |
| 888 | spin_lock(&sb_lock); |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 889 | list_for_each_entry(sb, &super_blocks, s_list) { |
Al Viro | a516616 | 2011-12-12 22:53:00 -0500 | [diff] [blame] | 890 | if (hlist_unhashed(&sb->s_instances)) |
Al Viro | 551de6f | 2010-03-22 19:36:35 -0400 | [diff] [blame] | 891 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 892 | sb->s_count++; |
| 893 | spin_unlock(&sb_lock); |
Al Viro | 443b94b | 2009-05-05 23:48:50 -0400 | [diff] [blame] | 894 | down_write(&sb->s_umount); |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 895 | if (sb->s_root && sb->s_bdev && (sb->s_flags & SB_BORN) && |
David Howells | bc98a42 | 2017-07-17 08:45:34 +0100 | [diff] [blame] | 896 | !sb_rdonly(sb)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 897 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 898 | * What lock protects sb->s_flags?? |
| 899 | */ |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 900 | do_remount_sb(sb, SB_RDONLY, NULL, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 901 | } |
Al Viro | 443b94b | 2009-05-05 23:48:50 -0400 | [diff] [blame] | 902 | up_write(&sb->s_umount); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 903 | spin_lock(&sb_lock); |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 904 | if (p) |
| 905 | __put_super(p); |
| 906 | p = sb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 907 | } |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 908 | if (p) |
| 909 | __put_super(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 910 | spin_unlock(&sb_lock); |
Jens Axboe | a2a9537 | 2009-03-17 09:38:40 +0100 | [diff] [blame] | 911 | kfree(work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 912 | printk("Emergency Remount complete\n"); |
| 913 | } |
| 914 | |
| 915 | void emergency_remount(void) |
| 916 | { |
Jens Axboe | a2a9537 | 2009-03-17 09:38:40 +0100 | [diff] [blame] | 917 | struct work_struct *work; |
| 918 | |
| 919 | work = kmalloc(sizeof(*work), GFP_ATOMIC); |
| 920 | if (work) { |
| 921 | INIT_WORK(work, do_emergency_remount); |
| 922 | schedule_work(work); |
| 923 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 924 | } |
| 925 | |
| 926 | /* |
| 927 | * Unnamed block devices are dummy devices used by virtual |
| 928 | * filesystems which don't use real block-devices. -- jrs |
| 929 | */ |
| 930 | |
Alexey Dobriyan | ad76cbc | 2008-08-28 06:26:23 +0400 | [diff] [blame] | 931 | static DEFINE_IDA(unnamed_dev_ida); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 932 | static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */ |
Thomas Bächler | a2a4dc4 | 2014-04-03 21:55:37 +0200 | [diff] [blame] | 933 | /* Many userspace utilities consider an FSID of 0 invalid. |
| 934 | * Always return at least 1 from get_anon_bdev. |
| 935 | */ |
| 936 | static int unnamed_dev_start = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 937 | |
Al Viro | 0ee5dc6 | 2011-07-07 15:44:25 -0400 | [diff] [blame] | 938 | int get_anon_bdev(dev_t *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 939 | { |
| 940 | int dev; |
| 941 | int error; |
| 942 | |
| 943 | retry: |
Alexey Dobriyan | ad76cbc | 2008-08-28 06:26:23 +0400 | [diff] [blame] | 944 | if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 945 | return -ENOMEM; |
| 946 | spin_lock(&unnamed_dev_lock); |
Al Viro | c63e09e | 2009-06-24 02:05:18 -0400 | [diff] [blame] | 947 | error = ida_get_new_above(&unnamed_dev_ida, unnamed_dev_start, &dev); |
Al Viro | f21f622 | 2009-06-24 03:12:00 -0400 | [diff] [blame] | 948 | if (!error) |
| 949 | unnamed_dev_start = dev + 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 950 | spin_unlock(&unnamed_dev_lock); |
| 951 | if (error == -EAGAIN) |
| 952 | /* We raced and lost with another CPU. */ |
| 953 | goto retry; |
| 954 | else if (error) |
| 955 | return -EAGAIN; |
| 956 | |
Wang YanQing | 1af95de | 2015-06-23 18:54:45 +0800 | [diff] [blame] | 957 | if (dev >= (1 << MINORBITS)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 958 | spin_lock(&unnamed_dev_lock); |
Alexey Dobriyan | ad76cbc | 2008-08-28 06:26:23 +0400 | [diff] [blame] | 959 | ida_remove(&unnamed_dev_ida, dev); |
Al Viro | f21f622 | 2009-06-24 03:12:00 -0400 | [diff] [blame] | 960 | if (unnamed_dev_start > dev) |
| 961 | unnamed_dev_start = dev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 962 | spin_unlock(&unnamed_dev_lock); |
| 963 | return -EMFILE; |
| 964 | } |
Al Viro | 0ee5dc6 | 2011-07-07 15:44:25 -0400 | [diff] [blame] | 965 | *p = MKDEV(0, dev & MINORMASK); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 966 | return 0; |
| 967 | } |
Al Viro | 0ee5dc6 | 2011-07-07 15:44:25 -0400 | [diff] [blame] | 968 | EXPORT_SYMBOL(get_anon_bdev); |
| 969 | |
| 970 | void free_anon_bdev(dev_t dev) |
| 971 | { |
| 972 | int slot = MINOR(dev); |
| 973 | spin_lock(&unnamed_dev_lock); |
| 974 | ida_remove(&unnamed_dev_ida, slot); |
| 975 | if (slot < unnamed_dev_start) |
| 976 | unnamed_dev_start = slot; |
| 977 | spin_unlock(&unnamed_dev_lock); |
| 978 | } |
| 979 | EXPORT_SYMBOL(free_anon_bdev); |
| 980 | |
| 981 | int set_anon_super(struct super_block *s, void *data) |
| 982 | { |
Christoph Hellwig | df0ce26 | 2015-01-14 10:42:41 +0100 | [diff] [blame] | 983 | return get_anon_bdev(&s->s_dev); |
Al Viro | 0ee5dc6 | 2011-07-07 15:44:25 -0400 | [diff] [blame] | 984 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 985 | |
| 986 | EXPORT_SYMBOL(set_anon_super); |
| 987 | |
| 988 | void kill_anon_super(struct super_block *sb) |
| 989 | { |
Al Viro | 0ee5dc6 | 2011-07-07 15:44:25 -0400 | [diff] [blame] | 990 | dev_t dev = sb->s_dev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 991 | generic_shutdown_super(sb); |
Al Viro | 0ee5dc6 | 2011-07-07 15:44:25 -0400 | [diff] [blame] | 992 | free_anon_bdev(dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 993 | } |
| 994 | |
| 995 | EXPORT_SYMBOL(kill_anon_super); |
| 996 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 997 | void kill_litter_super(struct super_block *sb) |
| 998 | { |
| 999 | if (sb->s_root) |
| 1000 | d_genocide(sb->s_root); |
| 1001 | kill_anon_super(sb); |
| 1002 | } |
| 1003 | |
| 1004 | EXPORT_SYMBOL(kill_litter_super); |
| 1005 | |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 1006 | static int ns_test_super(struct super_block *sb, void *data) |
| 1007 | { |
| 1008 | return sb->s_fs_info == data; |
| 1009 | } |
| 1010 | |
| 1011 | static int ns_set_super(struct super_block *sb, void *data) |
| 1012 | { |
| 1013 | sb->s_fs_info = data; |
| 1014 | return set_anon_super(sb, NULL); |
| 1015 | } |
| 1016 | |
Eric W. Biederman | d91ee87 | 2016-05-23 14:51:59 -0500 | [diff] [blame] | 1017 | struct dentry *mount_ns(struct file_system_type *fs_type, |
| 1018 | int flags, void *data, void *ns, struct user_namespace *user_ns, |
| 1019 | int (*fill_super)(struct super_block *, void *, int)) |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 1020 | { |
| 1021 | struct super_block *sb; |
| 1022 | |
Eric W. Biederman | d91ee87 | 2016-05-23 14:51:59 -0500 | [diff] [blame] | 1023 | /* Don't allow mounting unless the caller has CAP_SYS_ADMIN |
| 1024 | * over the namespace. |
| 1025 | */ |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1026 | if (!(flags & SB_KERNMOUNT) && !ns_capable(user_ns, CAP_SYS_ADMIN)) |
Eric W. Biederman | d91ee87 | 2016-05-23 14:51:59 -0500 | [diff] [blame] | 1027 | return ERR_PTR(-EPERM); |
| 1028 | |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 1029 | sb = sget_userns(fs_type, ns_test_super, ns_set_super, flags, |
| 1030 | user_ns, ns); |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 1031 | if (IS_ERR(sb)) |
Al Viro | ceefda6 | 2010-07-26 13:16:50 +0400 | [diff] [blame] | 1032 | return ERR_CAST(sb); |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 1033 | |
| 1034 | if (!sb->s_root) { |
| 1035 | int err; |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1036 | err = fill_super(sb, data, flags & SB_SILENT ? 1 : 0); |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 1037 | if (err) { |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 1038 | deactivate_locked_super(sb); |
Al Viro | ceefda6 | 2010-07-26 13:16:50 +0400 | [diff] [blame] | 1039 | return ERR_PTR(err); |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 1040 | } |
| 1041 | |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1042 | sb->s_flags |= SB_ACTIVE; |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 1043 | } |
| 1044 | |
Al Viro | ceefda6 | 2010-07-26 13:16:50 +0400 | [diff] [blame] | 1045 | return dget(sb->s_root); |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 1046 | } |
| 1047 | |
Al Viro | ceefda6 | 2010-07-26 13:16:50 +0400 | [diff] [blame] | 1048 | EXPORT_SYMBOL(mount_ns); |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 1049 | |
David Howells | 9361401 | 2006-09-30 20:45:40 +0200 | [diff] [blame] | 1050 | #ifdef CONFIG_BLOCK |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1051 | static int set_bdev_super(struct super_block *s, void *data) |
| 1052 | { |
| 1053 | s->s_bdev = data; |
| 1054 | s->s_dev = s->s_bdev->bd_dev; |
Jan Kara | 13eec23 | 2017-04-12 12:24:29 +0200 | [diff] [blame] | 1055 | s->s_bdi = bdi_get(s->s_bdev->bd_bdi); |
Jens Axboe | 32a88aa | 2009-09-16 15:02:33 +0200 | [diff] [blame] | 1056 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1057 | return 0; |
| 1058 | } |
| 1059 | |
| 1060 | static int test_bdev_super(struct super_block *s, void *data) |
| 1061 | { |
| 1062 | return (void *)s->s_bdev == data; |
| 1063 | } |
| 1064 | |
Al Viro | 152a083 | 2010-07-25 00:46:55 +0400 | [diff] [blame] | 1065 | struct dentry *mount_bdev(struct file_system_type *fs_type, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1066 | int flags, const char *dev_name, void *data, |
Al Viro | 152a083 | 2010-07-25 00:46:55 +0400 | [diff] [blame] | 1067 | int (*fill_super)(struct super_block *, void *, int)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1068 | { |
| 1069 | struct block_device *bdev; |
| 1070 | struct super_block *s; |
Tejun Heo | d4d7762 | 2010-11-13 11:55:18 +0100 | [diff] [blame] | 1071 | fmode_t mode = FMODE_READ | FMODE_EXCL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1072 | int error = 0; |
| 1073 | |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1074 | if (!(flags & SB_RDONLY)) |
Al Viro | 30c40d2 | 2008-02-22 19:50:45 -0500 | [diff] [blame] | 1075 | mode |= FMODE_WRITE; |
| 1076 | |
Tejun Heo | d4d7762 | 2010-11-13 11:55:18 +0100 | [diff] [blame] | 1077 | bdev = blkdev_get_by_path(dev_name, mode, fs_type); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1078 | if (IS_ERR(bdev)) |
Al Viro | 152a083 | 2010-07-25 00:46:55 +0400 | [diff] [blame] | 1079 | return ERR_CAST(bdev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1080 | |
| 1081 | /* |
| 1082 | * once the super is inserted into the list by sget, s_umount |
| 1083 | * will protect the lockfs code from trying to start a snapshot |
| 1084 | * while we are mounting |
| 1085 | */ |
Christoph Hellwig | 4fadd7b | 2009-08-03 23:28:06 +0200 | [diff] [blame] | 1086 | mutex_lock(&bdev->bd_fsfreeze_mutex); |
| 1087 | if (bdev->bd_fsfreeze_count > 0) { |
| 1088 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
| 1089 | error = -EBUSY; |
| 1090 | goto error_bdev; |
| 1091 | } |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1092 | s = sget(fs_type, test_bdev_super, set_bdev_super, flags | SB_NOSEC, |
David Howells | 9249e17 | 2012-06-25 12:55:37 +0100 | [diff] [blame] | 1093 | bdev); |
Christoph Hellwig | 4fadd7b | 2009-08-03 23:28:06 +0200 | [diff] [blame] | 1094 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1095 | if (IS_ERR(s)) |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1096 | goto error_s; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1097 | |
| 1098 | if (s->s_root) { |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1099 | if ((flags ^ s->s_flags) & SB_RDONLY) { |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 1100 | deactivate_locked_super(s); |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1101 | error = -EBUSY; |
| 1102 | goto error_bdev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1103 | } |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1104 | |
Tejun Heo | 4f331f0 | 2010-07-20 15:18:07 -0700 | [diff] [blame] | 1105 | /* |
| 1106 | * s_umount nests inside bd_mutex during |
Tejun Heo | e525fd8 | 2010-11-13 11:55:17 +0100 | [diff] [blame] | 1107 | * __invalidate_device(). blkdev_put() acquires |
| 1108 | * bd_mutex and can't be called under s_umount. Drop |
| 1109 | * s_umount temporarily. This is safe as we're |
| 1110 | * holding an active reference. |
Tejun Heo | 4f331f0 | 2010-07-20 15:18:07 -0700 | [diff] [blame] | 1111 | */ |
| 1112 | up_write(&s->s_umount); |
Tejun Heo | d4d7762 | 2010-11-13 11:55:18 +0100 | [diff] [blame] | 1113 | blkdev_put(bdev, mode); |
Tejun Heo | 4f331f0 | 2010-07-20 15:18:07 -0700 | [diff] [blame] | 1114 | down_write(&s->s_umount); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1115 | } else { |
Al Viro | 30c40d2 | 2008-02-22 19:50:45 -0500 | [diff] [blame] | 1116 | s->s_mode = mode; |
Dmitry Monakhov | a1c6f057 | 2015-04-13 16:31:37 +0400 | [diff] [blame] | 1117 | snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev); |
Pekka Enberg | e78c9a0 | 2006-01-08 01:03:39 -0800 | [diff] [blame] | 1118 | sb_set_blocksize(s, block_size(bdev)); |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1119 | error = fill_super(s, data, flags & SB_SILENT ? 1 : 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1120 | if (error) { |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 1121 | deactivate_locked_super(s); |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1122 | goto error; |
Greg Kroah-Hartman | fa67576 | 2006-02-22 09:39:02 -0800 | [diff] [blame] | 1123 | } |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1124 | |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1125 | s->s_flags |= SB_ACTIVE; |
Theodore Ts'o | 87d8fe1 | 2009-01-03 09:47:09 -0500 | [diff] [blame] | 1126 | bdev->bd_super = s; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1127 | } |
| 1128 | |
Al Viro | 152a083 | 2010-07-25 00:46:55 +0400 | [diff] [blame] | 1129 | return dget(s->s_root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1130 | |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1131 | error_s: |
| 1132 | error = PTR_ERR(s); |
| 1133 | error_bdev: |
Tejun Heo | d4d7762 | 2010-11-13 11:55:18 +0100 | [diff] [blame] | 1134 | blkdev_put(bdev, mode); |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1135 | error: |
Al Viro | 152a083 | 2010-07-25 00:46:55 +0400 | [diff] [blame] | 1136 | return ERR_PTR(error); |
| 1137 | } |
| 1138 | EXPORT_SYMBOL(mount_bdev); |
| 1139 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1140 | void kill_block_super(struct super_block *sb) |
| 1141 | { |
| 1142 | struct block_device *bdev = sb->s_bdev; |
Al Viro | 30c40d2 | 2008-02-22 19:50:45 -0500 | [diff] [blame] | 1143 | fmode_t mode = sb->s_mode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1144 | |
H Hartley Sweeten | ddbaaf3 | 2009-04-29 20:14:57 -0400 | [diff] [blame] | 1145 | bdev->bd_super = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1146 | generic_shutdown_super(sb); |
| 1147 | sync_blockdev(bdev); |
Tejun Heo | d4d7762 | 2010-11-13 11:55:18 +0100 | [diff] [blame] | 1148 | WARN_ON_ONCE(!(mode & FMODE_EXCL)); |
Tejun Heo | e525fd8 | 2010-11-13 11:55:17 +0100 | [diff] [blame] | 1149 | blkdev_put(bdev, mode | FMODE_EXCL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1150 | } |
| 1151 | |
| 1152 | EXPORT_SYMBOL(kill_block_super); |
David Howells | 9361401 | 2006-09-30 20:45:40 +0200 | [diff] [blame] | 1153 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1154 | |
Al Viro | 3c26ff6 | 2010-07-25 11:46:36 +0400 | [diff] [blame] | 1155 | struct dentry *mount_nodev(struct file_system_type *fs_type, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1156 | int flags, void *data, |
Al Viro | 3c26ff6 | 2010-07-25 11:46:36 +0400 | [diff] [blame] | 1157 | int (*fill_super)(struct super_block *, void *, int)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1158 | { |
| 1159 | int error; |
David Howells | 9249e17 | 2012-06-25 12:55:37 +0100 | [diff] [blame] | 1160 | struct super_block *s = sget(fs_type, NULL, set_anon_super, flags, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1161 | |
| 1162 | if (IS_ERR(s)) |
Al Viro | 3c26ff6 | 2010-07-25 11:46:36 +0400 | [diff] [blame] | 1163 | return ERR_CAST(s); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1164 | |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1165 | error = fill_super(s, data, flags & SB_SILENT ? 1 : 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1166 | if (error) { |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 1167 | deactivate_locked_super(s); |
Al Viro | 3c26ff6 | 2010-07-25 11:46:36 +0400 | [diff] [blame] | 1168 | return ERR_PTR(error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1169 | } |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1170 | s->s_flags |= SB_ACTIVE; |
Al Viro | 3c26ff6 | 2010-07-25 11:46:36 +0400 | [diff] [blame] | 1171 | return dget(s->s_root); |
| 1172 | } |
| 1173 | EXPORT_SYMBOL(mount_nodev); |
| 1174 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1175 | static int compare_single(struct super_block *s, void *p) |
| 1176 | { |
| 1177 | return 1; |
| 1178 | } |
| 1179 | |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 1180 | struct dentry *mount_single(struct file_system_type *fs_type, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1181 | int flags, void *data, |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 1182 | int (*fill_super)(struct super_block *, void *, int)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1183 | { |
| 1184 | struct super_block *s; |
| 1185 | int error; |
| 1186 | |
David Howells | 9249e17 | 2012-06-25 12:55:37 +0100 | [diff] [blame] | 1187 | s = sget(fs_type, compare_single, set_anon_super, flags, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1188 | if (IS_ERR(s)) |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 1189 | return ERR_CAST(s); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1190 | if (!s->s_root) { |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1191 | error = fill_super(s, data, flags & SB_SILENT ? 1 : 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1192 | if (error) { |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 1193 | deactivate_locked_super(s); |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 1194 | return ERR_PTR(error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1195 | } |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1196 | s->s_flags |= SB_ACTIVE; |
Kay Sievers | 9329d1be | 2009-12-18 21:18:15 +0100 | [diff] [blame] | 1197 | } else { |
| 1198 | do_remount_sb(s, flags, data, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1199 | } |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 1200 | return dget(s->s_root); |
| 1201 | } |
| 1202 | EXPORT_SYMBOL(mount_single); |
| 1203 | |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 1204 | struct dentry * |
| 1205 | mount_fs(struct file_system_type *type, int flags, const char *name, void *data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1206 | { |
Al Viro | c96e41e | 2010-07-25 00:17:56 +0400 | [diff] [blame] | 1207 | struct dentry *root; |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 1208 | struct super_block *sb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1209 | char *secdata = NULL; |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 1210 | int error = -ENOMEM; |
Al Viro | 8089352 | 2010-02-05 09:30:46 -0500 | [diff] [blame] | 1211 | |
Eric Paris | e000752 | 2008-03-05 10:31:54 -0500 | [diff] [blame] | 1212 | if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1213 | secdata = alloc_secdata(); |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1214 | if (!secdata) |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 1215 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1216 | |
Eric Paris | e000752 | 2008-03-05 10:31:54 -0500 | [diff] [blame] | 1217 | error = security_sb_copy_data(data, secdata); |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1218 | if (error) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1219 | goto out_free_secdata; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1220 | } |
| 1221 | |
Al Viro | 1a102ff | 2011-03-16 09:07:58 -0400 | [diff] [blame] | 1222 | root = type->mount(type, flags, name, data); |
| 1223 | if (IS_ERR(root)) { |
| 1224 | error = PTR_ERR(root); |
| 1225 | goto out_free_secdata; |
Al Viro | c96e41e | 2010-07-25 00:17:56 +0400 | [diff] [blame] | 1226 | } |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 1227 | sb = root->d_sb; |
| 1228 | BUG_ON(!sb); |
| 1229 | WARN_ON(!sb->s_bdi); |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1230 | sb->s_flags |= SB_BORN; |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1231 | |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 1232 | error = security_sb_kern_mount(sb, flags, secdata); |
Jörn Engel | 5129a46 | 2010-04-25 08:54:42 +0200 | [diff] [blame] | 1233 | if (error) |
| 1234 | goto out_sb; |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1235 | |
Jeff Layton | 42cb56a | 2009-09-18 13:05:53 -0700 | [diff] [blame] | 1236 | /* |
| 1237 | * filesystems should never set s_maxbytes larger than MAX_LFS_FILESIZE |
| 1238 | * but s_maxbytes was an unsigned long long for many releases. Throw |
| 1239 | * this warning for a little while to try and catch filesystems that |
Jeff Layton | 4358b56 | 2011-03-29 09:33:31 -0400 | [diff] [blame] | 1240 | * violate this rule. |
Jeff Layton | 42cb56a | 2009-09-18 13:05:53 -0700 | [diff] [blame] | 1241 | */ |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 1242 | WARN((sb->s_maxbytes < 0), "%s set sb->s_maxbytes to " |
| 1243 | "negative value (%lld)\n", type->name, sb->s_maxbytes); |
Jeff Layton | 42cb56a | 2009-09-18 13:05:53 -0700 | [diff] [blame] | 1244 | |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 1245 | up_write(&sb->s_umount); |
Gerald Schaefer | 8680e22 | 2005-06-21 17:15:16 -0700 | [diff] [blame] | 1246 | free_secdata(secdata); |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 1247 | return root; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1248 | out_sb: |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 1249 | dput(root); |
| 1250 | deactivate_locked_super(sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1251 | out_free_secdata: |
| 1252 | free_secdata(secdata); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1253 | out: |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1254 | return ERR_PTR(error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1255 | } |
| 1256 | |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1257 | /* |
Jan Kara | fca3934 | 2017-04-12 12:24:28 +0200 | [diff] [blame] | 1258 | * Setup private BDI for given superblock. It gets automatically cleaned up |
| 1259 | * in generic_shutdown_super(). |
| 1260 | */ |
| 1261 | int super_setup_bdi_name(struct super_block *sb, char *fmt, ...) |
| 1262 | { |
| 1263 | struct backing_dev_info *bdi; |
| 1264 | int err; |
| 1265 | va_list args; |
| 1266 | |
| 1267 | bdi = bdi_alloc(GFP_KERNEL); |
| 1268 | if (!bdi) |
| 1269 | return -ENOMEM; |
| 1270 | |
| 1271 | bdi->name = sb->s_type->name; |
| 1272 | |
| 1273 | va_start(args, fmt); |
Jan Kara | 7c4cc30 | 2017-04-12 12:24:49 +0200 | [diff] [blame] | 1274 | err = bdi_register_va(bdi, fmt, args); |
Jan Kara | fca3934 | 2017-04-12 12:24:28 +0200 | [diff] [blame] | 1275 | va_end(args); |
| 1276 | if (err) { |
| 1277 | bdi_put(bdi); |
| 1278 | return err; |
| 1279 | } |
| 1280 | WARN_ON(sb->s_bdi != &noop_backing_dev_info); |
| 1281 | sb->s_bdi = bdi; |
Jan Kara | fca3934 | 2017-04-12 12:24:28 +0200 | [diff] [blame] | 1282 | |
| 1283 | return 0; |
| 1284 | } |
| 1285 | EXPORT_SYMBOL(super_setup_bdi_name); |
| 1286 | |
| 1287 | /* |
| 1288 | * Setup private BDI for given superblock. I gets automatically cleaned up |
| 1289 | * in generic_shutdown_super(). |
| 1290 | */ |
| 1291 | int super_setup_bdi(struct super_block *sb) |
| 1292 | { |
| 1293 | static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0); |
| 1294 | |
| 1295 | return super_setup_bdi_name(sb, "%.28s-%ld", sb->s_type->name, |
| 1296 | atomic_long_inc_return(&bdi_seq)); |
| 1297 | } |
| 1298 | EXPORT_SYMBOL(super_setup_bdi); |
| 1299 | |
| 1300 | /* |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1301 | * This is an internal function, please use sb_end_{write,pagefault,intwrite} |
| 1302 | * instead. |
| 1303 | */ |
| 1304 | void __sb_end_write(struct super_block *sb, int level) |
| 1305 | { |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1306 | percpu_up_read(sb->s_writers.rw_sem + level-1); |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1307 | } |
| 1308 | EXPORT_SYMBOL(__sb_end_write); |
| 1309 | |
Oleg Nesterov | f4b554a | 2015-07-20 00:50:55 +0200 | [diff] [blame] | 1310 | /* |
| 1311 | * This is an internal function, please use sb_start_{write,pagefault,intwrite} |
| 1312 | * instead. |
| 1313 | */ |
| 1314 | int __sb_start_write(struct super_block *sb, int level, bool wait) |
| 1315 | { |
| 1316 | bool force_trylock = false; |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1317 | int ret = 1; |
Oleg Nesterov | f4b554a | 2015-07-20 00:50:55 +0200 | [diff] [blame] | 1318 | |
| 1319 | #ifdef CONFIG_LOCKDEP |
| 1320 | /* |
| 1321 | * We want lockdep to tell us about possible deadlocks with freezing |
| 1322 | * but it's it bit tricky to properly instrument it. Getting a freeze |
| 1323 | * protection works as getting a read lock but there are subtle |
| 1324 | * problems. XFS for example gets freeze protection on internal level |
| 1325 | * twice in some cases, which is OK only because we already hold a |
| 1326 | * freeze protection also on higher level. Due to these cases we have |
| 1327 | * to use wait == F (trylock mode) which must not fail. |
| 1328 | */ |
| 1329 | if (wait) { |
| 1330 | int i; |
| 1331 | |
| 1332 | for (i = 0; i < level - 1; i++) |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1333 | if (percpu_rwsem_is_held(sb->s_writers.rw_sem + i)) { |
Oleg Nesterov | f4b554a | 2015-07-20 00:50:55 +0200 | [diff] [blame] | 1334 | force_trylock = true; |
| 1335 | break; |
| 1336 | } |
| 1337 | } |
| 1338 | #endif |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1339 | if (wait && !force_trylock) |
| 1340 | percpu_down_read(sb->s_writers.rw_sem + level-1); |
| 1341 | else |
| 1342 | ret = percpu_down_read_trylock(sb->s_writers.rw_sem + level-1); |
| 1343 | |
Vincent Stehlé | 22224a1 | 2015-09-21 17:18:34 +0200 | [diff] [blame] | 1344 | WARN_ON(force_trylock && !ret); |
Oleg Nesterov | f4b554a | 2015-07-20 00:50:55 +0200 | [diff] [blame] | 1345 | return ret; |
| 1346 | } |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1347 | EXPORT_SYMBOL(__sb_start_write); |
| 1348 | |
| 1349 | /** |
| 1350 | * sb_wait_write - wait until all writers to given file system finish |
| 1351 | * @sb: the super for which we wait |
| 1352 | * @level: type of writers we wait for (normal vs page fault) |
| 1353 | * |
| 1354 | * This function waits until there are no writers of given type to given file |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1355 | * system. |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1356 | */ |
| 1357 | static void sb_wait_write(struct super_block *sb, int level) |
| 1358 | { |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1359 | percpu_down_write(sb->s_writers.rw_sem + level-1); |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1360 | } |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1361 | |
Oleg Nesterov | f1a9622 | 2016-09-26 18:55:25 +0200 | [diff] [blame] | 1362 | /* |
| 1363 | * We are going to return to userspace and forget about these locks, the |
| 1364 | * ownership goes to the caller of thaw_super() which does unlock(). |
| 1365 | */ |
| 1366 | static void lockdep_sb_freeze_release(struct super_block *sb) |
| 1367 | { |
| 1368 | int level; |
| 1369 | |
| 1370 | for (level = SB_FREEZE_LEVELS - 1; level >= 0; level--) |
| 1371 | percpu_rwsem_release(sb->s_writers.rw_sem + level, 0, _THIS_IP_); |
| 1372 | } |
| 1373 | |
| 1374 | /* |
| 1375 | * Tell lockdep we are holding these locks before we call ->unfreeze_fs(sb). |
| 1376 | */ |
| 1377 | static void lockdep_sb_freeze_acquire(struct super_block *sb) |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1378 | { |
| 1379 | int level; |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1380 | |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1381 | for (level = 0; level < SB_FREEZE_LEVELS; ++level) |
| 1382 | percpu_rwsem_acquire(sb->s_writers.rw_sem + level, 0, _THIS_IP_); |
Oleg Nesterov | f1a9622 | 2016-09-26 18:55:25 +0200 | [diff] [blame] | 1383 | } |
| 1384 | |
| 1385 | static void sb_freeze_unlock(struct super_block *sb) |
| 1386 | { |
| 1387 | int level; |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1388 | |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1389 | for (level = SB_FREEZE_LEVELS - 1; level >= 0; level--) |
| 1390 | percpu_up_write(sb->s_writers.rw_sem + level); |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1391 | } |
| 1392 | |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1393 | /** |
Randy Dunlap | 7000d3c | 2010-05-24 22:22:34 -0700 | [diff] [blame] | 1394 | * freeze_super - lock the filesystem and force it into a consistent state |
| 1395 | * @sb: the super to lock |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1396 | * |
| 1397 | * Syncs the super to make sure the filesystem is consistent and calls the fs's |
| 1398 | * freeze_fs. Subsequent calls to this without first thawing the fs will return |
| 1399 | * -EBUSY. |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1400 | * |
| 1401 | * During this function, sb->s_writers.frozen goes through these values: |
| 1402 | * |
| 1403 | * SB_UNFROZEN: File system is normal, all writes progress as usual. |
| 1404 | * |
| 1405 | * SB_FREEZE_WRITE: The file system is in the process of being frozen. New |
| 1406 | * writes should be blocked, though page faults are still allowed. We wait for |
| 1407 | * all writes to complete and then proceed to the next stage. |
| 1408 | * |
| 1409 | * SB_FREEZE_PAGEFAULT: Freezing continues. Now also page faults are blocked |
| 1410 | * but internal fs threads can still modify the filesystem (although they |
| 1411 | * should not dirty new pages or inodes), writeback can run etc. After waiting |
| 1412 | * for all running page faults we sync the filesystem which will clean all |
| 1413 | * dirty pages and inodes (no new dirty pages or inodes can be created when |
| 1414 | * sync is running). |
| 1415 | * |
| 1416 | * SB_FREEZE_FS: The file system is frozen. Now all internal sources of fs |
| 1417 | * modification are blocked (e.g. XFS preallocation truncation on inode |
| 1418 | * reclaim). This is usually implemented by blocking new transactions for |
| 1419 | * filesystems that have them and need this additional guard. After all |
| 1420 | * internal writers are finished we call ->freeze_fs() to finish filesystem |
| 1421 | * freezing. Then we transition to SB_FREEZE_COMPLETE state. This state is |
| 1422 | * mostly auxiliary for filesystems to verify they do not modify frozen fs. |
| 1423 | * |
| 1424 | * sb->s_writers.frozen is protected by sb->s_umount. |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1425 | */ |
| 1426 | int freeze_super(struct super_block *sb) |
| 1427 | { |
| 1428 | int ret; |
| 1429 | |
| 1430 | atomic_inc(&sb->s_active); |
| 1431 | down_write(&sb->s_umount); |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1432 | if (sb->s_writers.frozen != SB_UNFROZEN) { |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1433 | deactivate_locked_super(sb); |
| 1434 | return -EBUSY; |
| 1435 | } |
| 1436 | |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1437 | if (!(sb->s_flags & SB_BORN)) { |
Al Viro | dabe0dc | 2012-01-03 21:01:29 -0500 | [diff] [blame] | 1438 | up_write(&sb->s_umount); |
| 1439 | return 0; /* sic - it's "nothing to do" */ |
| 1440 | } |
| 1441 | |
David Howells | bc98a42 | 2017-07-17 08:45:34 +0100 | [diff] [blame] | 1442 | if (sb_rdonly(sb)) { |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1443 | /* Nothing to do really... */ |
| 1444 | sb->s_writers.frozen = SB_FREEZE_COMPLETE; |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1445 | up_write(&sb->s_umount); |
| 1446 | return 0; |
| 1447 | } |
| 1448 | |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1449 | sb->s_writers.frozen = SB_FREEZE_WRITE; |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1450 | /* Release s_umount to preserve sb_start_write -> s_umount ordering */ |
| 1451 | up_write(&sb->s_umount); |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1452 | sb_wait_write(sb, SB_FREEZE_WRITE); |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1453 | down_write(&sb->s_umount); |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1454 | |
| 1455 | /* Now we go and block page faults... */ |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1456 | sb->s_writers.frozen = SB_FREEZE_PAGEFAULT; |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1457 | sb_wait_write(sb, SB_FREEZE_PAGEFAULT); |
| 1458 | |
| 1459 | /* All writers are done so after syncing there won't be dirty data */ |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1460 | sync_filesystem(sb); |
| 1461 | |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1462 | /* Now wait for internal filesystem counter */ |
| 1463 | sb->s_writers.frozen = SB_FREEZE_FS; |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1464 | sb_wait_write(sb, SB_FREEZE_FS); |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1465 | |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1466 | if (sb->s_op->freeze_fs) { |
| 1467 | ret = sb->s_op->freeze_fs(sb); |
| 1468 | if (ret) { |
| 1469 | printk(KERN_ERR |
| 1470 | "VFS:Filesystem freeze failed\n"); |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1471 | sb->s_writers.frozen = SB_UNFROZEN; |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1472 | sb_freeze_unlock(sb); |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1473 | wake_up(&sb->s_writers.wait_unfrozen); |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1474 | deactivate_locked_super(sb); |
| 1475 | return ret; |
| 1476 | } |
| 1477 | } |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1478 | /* |
Oleg Nesterov | 89f39af | 2016-09-26 18:07:48 +0200 | [diff] [blame] | 1479 | * For debugging purposes so that fs can warn if it sees write activity |
| 1480 | * when frozen is set to SB_FREEZE_COMPLETE, and for thaw_super(). |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1481 | */ |
| 1482 | sb->s_writers.frozen = SB_FREEZE_COMPLETE; |
Oleg Nesterov | f1a9622 | 2016-09-26 18:55:25 +0200 | [diff] [blame] | 1483 | lockdep_sb_freeze_release(sb); |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1484 | up_write(&sb->s_umount); |
| 1485 | return 0; |
| 1486 | } |
| 1487 | EXPORT_SYMBOL(freeze_super); |
| 1488 | |
| 1489 | /** |
| 1490 | * thaw_super -- unlock filesystem |
| 1491 | * @sb: the super to thaw |
| 1492 | * |
| 1493 | * Unlocks the filesystem and marks it writeable again after freeze_super(). |
| 1494 | */ |
| 1495 | int thaw_super(struct super_block *sb) |
| 1496 | { |
| 1497 | int error; |
| 1498 | |
| 1499 | down_write(&sb->s_umount); |
Oleg Nesterov | 89f39af | 2016-09-26 18:07:48 +0200 | [diff] [blame] | 1500 | if (sb->s_writers.frozen != SB_FREEZE_COMPLETE) { |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1501 | up_write(&sb->s_umount); |
| 1502 | return -EINVAL; |
| 1503 | } |
| 1504 | |
David Howells | bc98a42 | 2017-07-17 08:45:34 +0100 | [diff] [blame] | 1505 | if (sb_rdonly(sb)) { |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1506 | sb->s_writers.frozen = SB_UNFROZEN; |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1507 | goto out; |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1508 | } |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1509 | |
Oleg Nesterov | f1a9622 | 2016-09-26 18:55:25 +0200 | [diff] [blame] | 1510 | lockdep_sb_freeze_acquire(sb); |
| 1511 | |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1512 | if (sb->s_op->unfreeze_fs) { |
| 1513 | error = sb->s_op->unfreeze_fs(sb); |
| 1514 | if (error) { |
| 1515 | printk(KERN_ERR |
| 1516 | "VFS:Filesystem thaw failed\n"); |
Oleg Nesterov | f1a9622 | 2016-09-26 18:55:25 +0200 | [diff] [blame] | 1517 | lockdep_sb_freeze_release(sb); |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1518 | up_write(&sb->s_umount); |
| 1519 | return error; |
| 1520 | } |
| 1521 | } |
| 1522 | |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1523 | sb->s_writers.frozen = SB_UNFROZEN; |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1524 | sb_freeze_unlock(sb); |
| 1525 | out: |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1526 | wake_up(&sb->s_writers.wait_unfrozen); |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1527 | deactivate_locked_super(sb); |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1528 | return 0; |
| 1529 | } |
| 1530 | EXPORT_SYMBOL(thaw_super); |