Greg Kroah-Hartman | b244131 | 2017-11-01 15:07:57 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | /* |
| 3 | * linux/fs/super.c |
| 4 | * |
| 5 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 6 | * |
| 7 | * super.c contains code to handle: - mount structures |
| 8 | * - super-block tables |
| 9 | * - filesystem drivers list |
| 10 | * - mount system call |
| 11 | * - umount system call |
| 12 | * - ustat system call |
| 13 | * |
| 14 | * GK 2/5/95 - Changed to support mounting the root fs via NFS |
| 15 | * |
| 16 | * Added kerneld support: Jacques Gelinas and Bjorn Ekwall |
| 17 | * Added change_root: Werner Almesberger & Hans Lermen, Feb '96 |
| 18 | * Added options to /proc/mounts: |
Jan Engelhardt | 96de0e2 | 2007-10-19 23:21:04 +0200 | [diff] [blame] | 19 | * Torbjörn Lindh (torbjorn.lindh@gopta.se), April 14, 1996. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | * Added devfs support: Richard Gooch <rgooch@atnf.csiro.au>, 13-JAN-1998 |
| 21 | * Heavily rewritten for 'one fs - one tree' dcache architecture. AV, Mar 2000 |
| 22 | */ |
| 23 | |
Paul Gortmaker | 630d9c4 | 2011-11-16 23:57:37 -0500 | [diff] [blame] | 24 | #include <linux/export.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | #include <linux/slab.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 26 | #include <linux/blkdev.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | #include <linux/mount.h> |
| 28 | #include <linux/security.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | #include <linux/writeback.h> /* for the emergency remount stuff */ |
| 30 | #include <linux/idr.h> |
Ingo Molnar | 353ab6e | 2006-03-26 01:37:12 -0800 | [diff] [blame] | 31 | #include <linux/mutex.h> |
Jens Axboe | 5477d0f | 2010-04-29 20:33:35 +0200 | [diff] [blame] | 32 | #include <linux/backing-dev.h> |
Nick Piggin | ceb5bdc | 2011-01-07 17:50:05 +1100 | [diff] [blame] | 33 | #include <linux/rculist_bl.h> |
Dan Magenheimer | c515e1f | 2011-05-26 10:01:43 -0600 | [diff] [blame] | 34 | #include <linux/cleancache.h> |
Al Viro | 4040153 | 2012-02-13 03:58:52 +0000 | [diff] [blame] | 35 | #include <linux/fsnotify.h> |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 36 | #include <linux/lockdep.h> |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 37 | #include <linux/user_namespace.h> |
David Howells | 9bc61ab | 2018-11-04 03:19:03 -0500 | [diff] [blame] | 38 | #include <linux/fs_context.h> |
David Howells | e262e32d | 2018-11-01 23:07:23 +0000 | [diff] [blame] | 39 | #include <uapi/linux/mount.h> |
Al Viro | 6d59e7f | 2008-03-22 15:48:17 -0400 | [diff] [blame] | 40 | #include "internal.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | |
Mateusz Guzik | 08fdc8a | 2017-10-03 18:17:41 +0200 | [diff] [blame] | 42 | static int thaw_super_locked(struct super_block *sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | |
Al Viro | 15d0f5e | 2015-02-02 10:07:59 -0700 | [diff] [blame] | 44 | static LIST_HEAD(super_blocks); |
| 45 | static DEFINE_SPINLOCK(sb_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 46 | |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 47 | static char *sb_writers_name[SB_FREEZE_LEVELS] = { |
| 48 | "sb_writers", |
| 49 | "sb_pagefaults", |
| 50 | "sb_internal", |
| 51 | }; |
| 52 | |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 53 | /* |
| 54 | * One thing we have to be careful of with a per-sb shrinker is that we don't |
| 55 | * drop the last active reference to the superblock from within the shrinker. |
| 56 | * If that happens we could trigger unregistering the shrinker from within the |
| 57 | * shrinker path and that leads to deadlock on the shrinker_rwsem. Hence we |
| 58 | * take a passive reference to the superblock to avoid this from occurring. |
| 59 | */ |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 60 | static unsigned long super_cache_scan(struct shrinker *shrink, |
| 61 | struct shrink_control *sc) |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 62 | { |
| 63 | struct super_block *sb; |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 64 | long fs_objects = 0; |
| 65 | long total_objects; |
| 66 | long freed = 0; |
| 67 | long dentries; |
| 68 | long inodes; |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 69 | |
| 70 | sb = container_of(shrink, struct super_block, s_shrink); |
| 71 | |
| 72 | /* |
| 73 | * Deadlock avoidance. We may hold various FS locks, and we don't want |
| 74 | * to recurse into the FS that called us in clear_inode() and friends.. |
| 75 | */ |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 76 | if (!(sc->gfp_mask & __GFP_FS)) |
| 77 | return SHRINK_STOP; |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 78 | |
Konstantin Khlebnikov | eb6ef3d | 2015-02-19 20:19:35 +0300 | [diff] [blame] | 79 | if (!trylock_super(sb)) |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 80 | return SHRINK_STOP; |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 81 | |
Al Viro | d040790 | 2013-07-19 21:12:31 +0400 | [diff] [blame] | 82 | if (sb->s_op->nr_cached_objects) |
Vladimir Davydov | 4101b62 | 2015-02-12 14:58:51 -0800 | [diff] [blame] | 83 | fs_objects = sb->s_op->nr_cached_objects(sb, sc); |
Dave Chinner | 0e1fdaf | 2011-07-08 14:14:44 +1000 | [diff] [blame] | 84 | |
Vladimir Davydov | 503c358 | 2015-02-12 14:58:47 -0800 | [diff] [blame] | 85 | inodes = list_lru_shrink_count(&sb->s_inode_lru, sc); |
| 86 | dentries = list_lru_shrink_count(&sb->s_dentry_lru, sc); |
Dave Chinner | f604156 | 2013-08-28 10:18:00 +1000 | [diff] [blame] | 87 | total_objects = dentries + inodes + fs_objects + 1; |
Tetsuo Handa | 475d0db | 2014-05-17 20:56:38 +0900 | [diff] [blame] | 88 | if (!total_objects) |
| 89 | total_objects = 1; |
Dave Chinner | 0e1fdaf | 2011-07-08 14:14:44 +1000 | [diff] [blame] | 90 | |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 91 | /* proportion the scan between the caches */ |
Dave Chinner | f604156 | 2013-08-28 10:18:00 +1000 | [diff] [blame] | 92 | dentries = mult_frac(sc->nr_to_scan, dentries, total_objects); |
Dave Chinner | bc3b14c | 2013-08-28 10:17:58 +1000 | [diff] [blame] | 93 | inodes = mult_frac(sc->nr_to_scan, inodes, total_objects); |
Vladimir Davydov | 503c358 | 2015-02-12 14:58:47 -0800 | [diff] [blame] | 94 | fs_objects = mult_frac(sc->nr_to_scan, fs_objects, total_objects); |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 95 | |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 96 | /* |
| 97 | * prune the dcache first as the icache is pinned by it, then |
| 98 | * prune the icache, followed by the filesystem specific caches |
Vladimir Davydov | 49e7e7f | 2015-02-12 14:59:17 -0800 | [diff] [blame] | 99 | * |
| 100 | * Ensure that we always scan at least one object - memcg kmem |
| 101 | * accounting uses this to fully empty the caches. |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 102 | */ |
Vladimir Davydov | 49e7e7f | 2015-02-12 14:59:17 -0800 | [diff] [blame] | 103 | sc->nr_to_scan = dentries + 1; |
Vladimir Davydov | 503c358 | 2015-02-12 14:58:47 -0800 | [diff] [blame] | 104 | freed = prune_dcache_sb(sb, sc); |
Vladimir Davydov | 49e7e7f | 2015-02-12 14:59:17 -0800 | [diff] [blame] | 105 | sc->nr_to_scan = inodes + 1; |
Vladimir Davydov | 503c358 | 2015-02-12 14:58:47 -0800 | [diff] [blame] | 106 | freed += prune_icache_sb(sb, sc); |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 107 | |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 108 | if (fs_objects) { |
Vladimir Davydov | 49e7e7f | 2015-02-12 14:59:17 -0800 | [diff] [blame] | 109 | sc->nr_to_scan = fs_objects + 1; |
Vladimir Davydov | 4101b62 | 2015-02-12 14:58:51 -0800 | [diff] [blame] | 110 | freed += sb->s_op->free_cached_objects(sb, sc); |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 111 | } |
| 112 | |
Konstantin Khlebnikov | eb6ef3d | 2015-02-19 20:19:35 +0300 | [diff] [blame] | 113 | up_read(&sb->s_umount); |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 114 | return freed; |
| 115 | } |
| 116 | |
| 117 | static unsigned long super_cache_count(struct shrinker *shrink, |
| 118 | struct shrink_control *sc) |
| 119 | { |
| 120 | struct super_block *sb; |
| 121 | long total_objects = 0; |
| 122 | |
| 123 | sb = container_of(shrink, struct super_block, s_shrink); |
| 124 | |
Tim Chen | d23da15 | 2014-06-04 16:10:47 -0700 | [diff] [blame] | 125 | /* |
Dave Chinner | 79f546a | 2018-05-11 11:20:57 +1000 | [diff] [blame] | 126 | * We don't call trylock_super() here as it is a scalability bottleneck, |
| 127 | * so we're exposed to partial setup state. The shrinker rwsem does not |
| 128 | * protect filesystem operations backing list_lru_shrink_count() or |
| 129 | * s_op->nr_cached_objects(). Counts can change between |
| 130 | * super_cache_count and super_cache_scan, so we really don't need locks |
| 131 | * here. |
| 132 | * |
| 133 | * However, if we are currently mounting the superblock, the underlying |
| 134 | * filesystem might be in a state of partial construction and hence it |
| 135 | * is dangerous to access it. trylock_super() uses a SB_BORN check to |
| 136 | * avoid this situation, so do the same here. The memory barrier is |
| 137 | * matched with the one in mount_fs() as we don't hold locks here. |
Tim Chen | d23da15 | 2014-06-04 16:10:47 -0700 | [diff] [blame] | 138 | */ |
Dave Chinner | 79f546a | 2018-05-11 11:20:57 +1000 | [diff] [blame] | 139 | if (!(sb->s_flags & SB_BORN)) |
| 140 | return 0; |
| 141 | smp_rmb(); |
| 142 | |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 143 | if (sb->s_op && sb->s_op->nr_cached_objects) |
Vladimir Davydov | 4101b62 | 2015-02-12 14:58:51 -0800 | [diff] [blame] | 144 | total_objects = sb->s_op->nr_cached_objects(sb, sc); |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 145 | |
Vladimir Davydov | 503c358 | 2015-02-12 14:58:47 -0800 | [diff] [blame] | 146 | total_objects += list_lru_shrink_count(&sb->s_dentry_lru, sc); |
| 147 | total_objects += list_lru_shrink_count(&sb->s_inode_lru, sc); |
Dave Chinner | 0a234c6 | 2013-08-28 10:17:57 +1000 | [diff] [blame] | 148 | |
Kirill Tkhai | 9b99646 | 2018-08-17 15:48:21 -0700 | [diff] [blame] | 149 | if (!total_objects) |
| 150 | return SHRINK_EMPTY; |
| 151 | |
Glauber Costa | 55f841c | 2013-08-28 10:17:53 +1000 | [diff] [blame] | 152 | total_objects = vfs_pressure_ratio(total_objects); |
Dave Chinner | 0e1fdaf | 2011-07-08 14:14:44 +1000 | [diff] [blame] | 153 | return total_objects; |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 154 | } |
| 155 | |
Oleg Nesterov | 853b39a | 2015-07-22 20:21:13 +0200 | [diff] [blame] | 156 | static void destroy_super_work(struct work_struct *work) |
| 157 | { |
| 158 | struct super_block *s = container_of(work, struct super_block, |
| 159 | destroy_work); |
| 160 | int i; |
| 161 | |
| 162 | for (i = 0; i < SB_FREEZE_LEVELS; i++) |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 163 | percpu_free_rwsem(&s->s_writers.rw_sem[i]); |
Oleg Nesterov | 853b39a | 2015-07-22 20:21:13 +0200 | [diff] [blame] | 164 | kfree(s); |
| 165 | } |
| 166 | |
| 167 | static void destroy_super_rcu(struct rcu_head *head) |
| 168 | { |
| 169 | struct super_block *s = container_of(head, struct super_block, rcu); |
| 170 | INIT_WORK(&s->destroy_work, destroy_super_work); |
| 171 | schedule_work(&s->destroy_work); |
| 172 | } |
| 173 | |
Al Viro | 0200894 | 2017-10-11 13:48:55 -0400 | [diff] [blame] | 174 | /* Free a superblock that has never been seen by anyone */ |
| 175 | static void destroy_unused_super(struct super_block *s) |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 176 | { |
Al Viro | 0200894 | 2017-10-11 13:48:55 -0400 | [diff] [blame] | 177 | if (!s) |
| 178 | return; |
| 179 | up_write(&s->s_umount); |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 180 | list_lru_destroy(&s->s_dentry_lru); |
| 181 | list_lru_destroy(&s->s_inode_lru); |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 182 | security_sb_free(s); |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 183 | put_user_ns(s->s_user_ns); |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 184 | kfree(s->s_subtype); |
Tetsuo Handa | 8e04944 | 2018-04-04 19:53:07 +0900 | [diff] [blame] | 185 | free_prealloced_shrinker(&s->s_shrink); |
Al Viro | 0200894 | 2017-10-11 13:48:55 -0400 | [diff] [blame] | 186 | /* no delays needed */ |
| 187 | destroy_super_work(&s->destroy_work); |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 188 | } |
| 189 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 190 | /** |
| 191 | * alloc_super - create new superblock |
Henrik Kretzschmar | fe2bbc4 | 2006-09-06 00:03:41 -0700 | [diff] [blame] | 192 | * @type: filesystem type superblock should belong to |
David Howells | 9249e17 | 2012-06-25 12:55:37 +0100 | [diff] [blame] | 193 | * @flags: the mount flags |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 194 | * @user_ns: User namespace for the super_block |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 195 | * |
| 196 | * Allocates and initializes a new &struct super_block. alloc_super() |
| 197 | * returns a pointer new superblock or %NULL if allocation had failed. |
| 198 | */ |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 199 | static struct super_block *alloc_super(struct file_system_type *type, int flags, |
| 200 | struct user_namespace *user_ns) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 201 | { |
Oliver Neukum | 11b0b5a | 2006-03-25 03:08:13 -0800 | [diff] [blame] | 202 | struct super_block *s = kzalloc(sizeof(struct super_block), GFP_USER); |
Alexey Dobriyan | b87221d | 2009-09-21 17:01:09 -0700 | [diff] [blame] | 203 | static const struct super_operations default_op; |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 204 | int i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 205 | |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 206 | if (!s) |
| 207 | return NULL; |
| 208 | |
Vladimir Davydov | b5bd856 | 2014-01-21 15:48:45 -0800 | [diff] [blame] | 209 | INIT_LIST_HEAD(&s->s_mounts); |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 210 | s->s_user_ns = get_user_ns(user_ns); |
Al Viro | ca0168e | 2017-12-05 09:32:25 -0500 | [diff] [blame] | 211 | init_rwsem(&s->s_umount); |
| 212 | lockdep_set_class(&s->s_umount, &type->s_umount_key); |
| 213 | /* |
| 214 | * sget() can have s_umount recursion. |
| 215 | * |
| 216 | * When it cannot find a suitable sb, it allocates a new |
| 217 | * one (this one), and tries again to find a suitable old |
| 218 | * one. |
| 219 | * |
| 220 | * In case that succeeds, it will acquire the s_umount |
| 221 | * lock of the old one. Since these are clearly distrinct |
| 222 | * locks, and this object isn't exposed yet, there's no |
| 223 | * risk of deadlocks. |
| 224 | * |
| 225 | * Annotate this by putting this lock in a different |
| 226 | * subclass. |
| 227 | */ |
| 228 | down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING); |
Vladimir Davydov | b5bd856 | 2014-01-21 15:48:45 -0800 | [diff] [blame] | 229 | |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 230 | if (security_sb_alloc(s)) |
| 231 | goto fail; |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 232 | |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 233 | for (i = 0; i < SB_FREEZE_LEVELS; i++) { |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 234 | if (__percpu_init_rwsem(&s->s_writers.rw_sem[i], |
| 235 | sb_writers_name[i], |
| 236 | &type->s_writers_key[i])) |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 237 | goto fail; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 238 | } |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 239 | init_waitqueue_head(&s->s_writers.wait_unfrozen); |
Christoph Hellwig | df0ce26 | 2015-01-14 10:42:41 +0100 | [diff] [blame] | 240 | s->s_bdi = &noop_backing_dev_info; |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 241 | s->s_flags = flags; |
Eric W. Biederman | cc50a07 | 2016-06-09 15:44:48 -0500 | [diff] [blame] | 242 | if (s->s_user_ns != &init_user_ns) |
Eric W. Biederman | 67690f9 | 2016-05-18 13:50:06 -0500 | [diff] [blame] | 243 | s->s_iflags |= SB_I_NODEV; |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 244 | INIT_HLIST_NODE(&s->s_instances); |
NeilBrown | f1ee616 | 2017-12-21 09:45:40 +1100 | [diff] [blame] | 245 | INIT_HLIST_BL_HEAD(&s->s_roots); |
Dave Chinner | e97fedb | 2015-03-04 13:40:00 -0500 | [diff] [blame] | 246 | mutex_init(&s->s_sync_lock); |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 247 | INIT_LIST_HEAD(&s->s_inodes); |
Dave Chinner | 74278da9 | 2015-03-04 12:37:22 -0500 | [diff] [blame] | 248 | spin_lock_init(&s->s_inode_list_lock); |
Dave Chinner | 6c60d2b | 2016-07-26 15:21:50 -0700 | [diff] [blame] | 249 | INIT_LIST_HEAD(&s->s_inodes_wb); |
| 250 | spin_lock_init(&s->s_inode_wblist_lock); |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 251 | |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 252 | s->s_count = 1; |
| 253 | atomic_set(&s->s_active, 1); |
| 254 | mutex_init(&s->s_vfs_rename_mutex); |
| 255 | 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] | 256 | init_rwsem(&s->s_dquot.dqio_sem); |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 257 | s->s_maxbytes = MAX_NON_LFS; |
| 258 | s->s_op = &default_op; |
| 259 | s->s_time_gran = 1000000000; |
Vladimir Davydov | 3cb29d1 | 2015-04-14 15:46:48 -0700 | [diff] [blame] | 260 | s->cleancache_poolid = CLEANCACHE_NO_POOL; |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 261 | |
| 262 | s->s_shrink.seeks = DEFAULT_SEEKS; |
| 263 | s->s_shrink.scan_objects = super_cache_scan; |
| 264 | s->s_shrink.count_objects = super_cache_count; |
| 265 | s->s_shrink.batch = 1024; |
Vladimir Davydov | 2acb60a | 2015-02-12 14:59:14 -0800 | [diff] [blame] | 266 | s->s_shrink.flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE; |
Tetsuo Handa | 8e04944 | 2018-04-04 19:53:07 +0900 | [diff] [blame] | 267 | if (prealloc_shrinker(&s->s_shrink)) |
| 268 | goto fail; |
Kirill Tkhai | c92e8e1 | 2018-08-17 15:47:50 -0700 | [diff] [blame] | 269 | if (list_lru_init_memcg(&s->s_dentry_lru, &s->s_shrink)) |
Kirill Tkhai | 2b3648a | 2018-08-17 15:47:45 -0700 | [diff] [blame] | 270 | goto fail; |
Kirill Tkhai | c92e8e1 | 2018-08-17 15:47:50 -0700 | [diff] [blame] | 271 | if (list_lru_init_memcg(&s->s_inode_lru, &s->s_shrink)) |
Kirill Tkhai | 2b3648a | 2018-08-17 15:47:45 -0700 | [diff] [blame] | 272 | goto fail; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 273 | return s; |
Glauber Costa | 5ca302c | 2013-08-28 10:18:18 +1000 | [diff] [blame] | 274 | |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 275 | fail: |
Al Viro | 0200894 | 2017-10-11 13:48:55 -0400 | [diff] [blame] | 276 | destroy_unused_super(s); |
Al Viro | 7eb5e88 | 2013-10-01 15:09:58 -0400 | [diff] [blame] | 277 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 278 | } |
| 279 | |
| 280 | /* Superblock refcounting */ |
| 281 | |
| 282 | /* |
Al Viro | 35cf7ba | 2010-03-22 21:13:53 -0400 | [diff] [blame] | 283 | * Drop a superblock's refcount. The caller must hold sb_lock. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 284 | */ |
Al Viro | c645b93 | 2017-10-11 13:48:55 -0400 | [diff] [blame] | 285 | static void __put_super(struct super_block *s) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 286 | { |
Al Viro | c645b93 | 2017-10-11 13:48:55 -0400 | [diff] [blame] | 287 | if (!--s->s_count) { |
| 288 | list_del_init(&s->s_list); |
| 289 | WARN_ON(s->s_dentry_lru.node); |
| 290 | WARN_ON(s->s_inode_lru.node); |
| 291 | WARN_ON(!list_empty(&s->s_mounts)); |
| 292 | security_sb_free(s); |
| 293 | put_user_ns(s->s_user_ns); |
| 294 | kfree(s->s_subtype); |
| 295 | call_rcu(&s->rcu, destroy_super_rcu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 296 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 297 | } |
| 298 | |
| 299 | /** |
| 300 | * put_super - drop a temporary reference to superblock |
| 301 | * @sb: superblock in question |
| 302 | * |
| 303 | * Drops a temporary reference, frees superblock if there's no |
| 304 | * references left. |
| 305 | */ |
Al Viro | f47ec3f2 | 2011-11-21 21:15:42 -0500 | [diff] [blame] | 306 | static void put_super(struct super_block *sb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 307 | { |
| 308 | spin_lock(&sb_lock); |
| 309 | __put_super(sb); |
| 310 | spin_unlock(&sb_lock); |
| 311 | } |
| 312 | |
| 313 | |
| 314 | /** |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 315 | * deactivate_locked_super - drop an active reference to superblock |
| 316 | * @s: superblock to deactivate |
| 317 | * |
Masanari Iida | bd7ced9 | 2016-02-02 22:31:06 +0900 | [diff] [blame] | 318 | * Drops an active reference to superblock, converting it into a temporary |
Al Viro | 1712ac8 | 2010-03-22 15:22:31 -0400 | [diff] [blame] | 319 | * one if there is no other active references left. In that case we |
| 320 | * tell fs driver to shut it down and drop the temporary reference we |
| 321 | * had just acquired. |
| 322 | * |
| 323 | * Caller holds exclusive lock on superblock; that lock is released. |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 324 | */ |
| 325 | void deactivate_locked_super(struct super_block *s) |
| 326 | { |
| 327 | struct file_system_type *fs = s->s_type; |
Al Viro | b20bd1a | 2010-03-22 08:53:19 -0400 | [diff] [blame] | 328 | if (atomic_dec_and_test(&s->s_active)) { |
Dan Magenheimer | 3167760 | 2011-09-21 11:56:28 -0400 | [diff] [blame] | 329 | cleancache_invalidate_fs(s); |
Dave Chinner | b0d40c9 | 2011-07-08 14:14:42 +1000 | [diff] [blame] | 330 | unregister_shrinker(&s->s_shrink); |
Dave Chinner | 28f2cd4f | 2014-06-04 16:10:46 -0700 | [diff] [blame] | 331 | fs->kill_sb(s); |
Glauber Costa | f5e1dd3 | 2013-08-28 10:18:18 +1000 | [diff] [blame] | 332 | |
Vladimir Davydov | c0a5b56 | 2015-02-12 14:59:07 -0800 | [diff] [blame] | 333 | /* |
| 334 | * Since list_lru_destroy() may sleep, we cannot call it from |
| 335 | * put_super(), where we hold the sb_lock. Therefore we destroy |
| 336 | * the lru lists right now. |
| 337 | */ |
| 338 | list_lru_destroy(&s->s_dentry_lru); |
| 339 | list_lru_destroy(&s->s_inode_lru); |
| 340 | |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 341 | put_filesystem(fs); |
| 342 | put_super(s); |
| 343 | } else { |
| 344 | up_write(&s->s_umount); |
| 345 | } |
| 346 | } |
| 347 | |
| 348 | EXPORT_SYMBOL(deactivate_locked_super); |
| 349 | |
| 350 | /** |
Al Viro | 1712ac8 | 2010-03-22 15:22:31 -0400 | [diff] [blame] | 351 | * deactivate_super - drop an active reference to superblock |
| 352 | * @s: superblock to deactivate |
| 353 | * |
| 354 | * Variant of deactivate_locked_super(), except that superblock is *not* |
| 355 | * locked by caller. If we are going to drop the final active reference, |
| 356 | * lock will be acquired prior to that. |
| 357 | */ |
| 358 | void deactivate_super(struct super_block *s) |
| 359 | { |
| 360 | if (!atomic_add_unless(&s->s_active, -1, 1)) { |
| 361 | down_write(&s->s_umount); |
| 362 | deactivate_locked_super(s); |
| 363 | } |
| 364 | } |
| 365 | |
| 366 | EXPORT_SYMBOL(deactivate_super); |
| 367 | |
| 368 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 369 | * grab_super - acquire an active reference |
| 370 | * @s: reference we are trying to make active |
| 371 | * |
| 372 | * Tries to acquire an active reference. grab_super() is used when we |
| 373 | * had just found a superblock in super_blocks or fs_type->fs_supers |
| 374 | * and want to turn it into a full-blown active reference. grab_super() |
| 375 | * is called with sb_lock held and drops it. Returns 1 in case of |
| 376 | * success, 0 if we had failed (superblock contents was already dead or |
Al Viro | acfec9a | 2013-07-20 03:13:55 +0400 | [diff] [blame] | 377 | * dying when grab_super() had been called). Note that this is only |
| 378 | * called for superblocks not in rundown mode (== ones still on ->fs_supers |
| 379 | * of their type), so increment of ->s_count is OK here. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 380 | */ |
Josh Triplett | 9c4dbee | 2006-09-29 01:59:29 -0700 | [diff] [blame] | 381 | static int grab_super(struct super_block *s) __releases(sb_lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 382 | { |
| 383 | s->s_count++; |
| 384 | spin_unlock(&sb_lock); |
| 385 | down_write(&s->s_umount); |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 386 | 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] | 387 | put_super(s); |
| 388 | return 1; |
| 389 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 390 | up_write(&s->s_umount); |
| 391 | put_super(s); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | return 0; |
| 393 | } |
| 394 | |
David Howells | cf9a2ae | 2006-08-29 19:05:54 +0100 | [diff] [blame] | 395 | /* |
Konstantin Khlebnikov | eb6ef3d | 2015-02-19 20:19:35 +0300 | [diff] [blame] | 396 | * trylock_super - try to grab ->s_umount shared |
Wanpeng Li | 331cbde | 2012-06-09 11:10:55 +0800 | [diff] [blame] | 397 | * @sb: reference we are trying to grab |
Dave Chinner | 12ad3ab | 2011-07-08 14:14:41 +1000 | [diff] [blame] | 398 | * |
Konstantin Khlebnikov | eb6ef3d | 2015-02-19 20:19:35 +0300 | [diff] [blame] | 399 | * Try to prevent fs shutdown. This is used in places where we |
Dave Chinner | 12ad3ab | 2011-07-08 14:14:41 +1000 | [diff] [blame] | 400 | * cannot take an active reference but we need to ensure that the |
Konstantin Khlebnikov | eb6ef3d | 2015-02-19 20:19:35 +0300 | [diff] [blame] | 401 | * filesystem is not shut down while we are working on it. It returns |
| 402 | * false if we cannot acquire s_umount or if we lose the race and |
| 403 | * filesystem already got into shutdown, and returns true with the s_umount |
| 404 | * lock held in read mode in case of success. On successful return, |
| 405 | * the caller must drop the s_umount lock when done. |
| 406 | * |
| 407 | * Note that unlike get_super() et.al. this one does *not* bump ->s_count. |
| 408 | * The reason why it's safe is that we are OK with doing trylock instead |
| 409 | * of down_read(). There's a couple of places that are OK with that, but |
| 410 | * it's very much not a general-purpose interface. |
Dave Chinner | 12ad3ab | 2011-07-08 14:14:41 +1000 | [diff] [blame] | 411 | */ |
Konstantin Khlebnikov | eb6ef3d | 2015-02-19 20:19:35 +0300 | [diff] [blame] | 412 | bool trylock_super(struct super_block *sb) |
Dave Chinner | 12ad3ab | 2011-07-08 14:14:41 +1000 | [diff] [blame] | 413 | { |
Dave Chinner | 12ad3ab | 2011-07-08 14:14:41 +1000 | [diff] [blame] | 414 | if (down_read_trylock(&sb->s_umount)) { |
Konstantin Khlebnikov | eb6ef3d | 2015-02-19 20:19:35 +0300 | [diff] [blame] | 415 | if (!hlist_unhashed(&sb->s_instances) && |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 416 | sb->s_root && (sb->s_flags & SB_BORN)) |
Dave Chinner | 12ad3ab | 2011-07-08 14:14:41 +1000 | [diff] [blame] | 417 | return true; |
| 418 | up_read(&sb->s_umount); |
| 419 | } |
| 420 | |
Dave Chinner | 12ad3ab | 2011-07-08 14:14:41 +1000 | [diff] [blame] | 421 | return false; |
| 422 | } |
| 423 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 424 | /** |
| 425 | * generic_shutdown_super - common helper for ->kill_sb() |
| 426 | * @sb: superblock to kill |
| 427 | * |
| 428 | * generic_shutdown_super() does all fs-independent work on superblock |
| 429 | * shutdown. Typical ->kill_sb() should pick all fs-specific objects |
| 430 | * that need destruction out of superblock, call generic_shutdown_super() |
| 431 | * and release aforementioned objects. Note: dentries and inodes _are_ |
| 432 | * taken care of and do not need specific handling. |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 433 | * |
| 434 | * Upon calling this function, the filesystem may no longer alter or |
| 435 | * rearrange the set of dentries belonging to this super_block, nor may it |
| 436 | * change the attachments of dentries to inodes. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 437 | */ |
| 438 | void generic_shutdown_super(struct super_block *sb) |
| 439 | { |
Josef 'Jeff' Sipek | ee9b6d6 | 2007-02-12 00:55:41 -0800 | [diff] [blame] | 440 | const struct super_operations *sop = sb->s_op; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 441 | |
David Howells | c636ebd | 2006-10-11 01:22:19 -0700 | [diff] [blame] | 442 | if (sb->s_root) { |
| 443 | shrink_dcache_for_umount(sb); |
Jan Kara | 60b0680 | 2009-04-27 16:43:53 +0200 | [diff] [blame] | 444 | sync_filesystem(sb); |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 445 | sb->s_flags &= ~SB_ACTIVE; |
Arjan van de Ven | efaee19 | 2009-01-06 07:20:54 -0800 | [diff] [blame] | 446 | |
Amir Goldstein | 1e6cb72 | 2018-09-01 10:41:11 +0300 | [diff] [blame] | 447 | fsnotify_sb_delete(sb); |
Tejun Heo | a1a0e23 | 2016-02-29 18:28:53 -0500 | [diff] [blame] | 448 | cgroup_writeback_umount(); |
Al Viro | 63997e9 | 2010-10-25 20:49:35 -0400 | [diff] [blame] | 449 | |
| 450 | evict_inodes(sb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 451 | |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 452 | if (sb->s_dio_done_wq) { |
| 453 | destroy_workqueue(sb->s_dio_done_wq); |
| 454 | sb->s_dio_done_wq = NULL; |
| 455 | } |
| 456 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 457 | if (sop->put_super) |
| 458 | sop->put_super(sb); |
| 459 | |
Al Viro | 63997e9 | 2010-10-25 20:49:35 -0400 | [diff] [blame] | 460 | if (!list_empty(&sb->s_inodes)) { |
Dave Jones | 7b4fe29 | 2006-02-07 12:58:48 -0800 | [diff] [blame] | 461 | printk("VFS: Busy inodes after unmount of %s. " |
| 462 | "Self-destruct in 5 seconds. Have a nice day...\n", |
| 463 | sb->s_id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 464 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 465 | } |
| 466 | spin_lock(&sb_lock); |
| 467 | /* should be initialized for __put_super_and_need_restart() */ |
Al Viro | a516616 | 2011-12-12 22:53:00 -0500 | [diff] [blame] | 468 | hlist_del_init(&sb->s_instances); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 469 | spin_unlock(&sb_lock); |
| 470 | up_write(&sb->s_umount); |
Jan Kara | c1844d5 | 2017-04-12 12:24:47 +0200 | [diff] [blame] | 471 | if (sb->s_bdi != &noop_backing_dev_info) { |
Jan Kara | fca3934 | 2017-04-12 12:24:28 +0200 | [diff] [blame] | 472 | bdi_put(sb->s_bdi); |
| 473 | sb->s_bdi = &noop_backing_dev_info; |
Jan Kara | fca3934 | 2017-04-12 12:24:28 +0200 | [diff] [blame] | 474 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 475 | } |
| 476 | |
| 477 | EXPORT_SYMBOL(generic_shutdown_super); |
| 478 | |
| 479 | /** |
Al Viro | cb50b34 | 2018-12-23 17:25:47 -0500 | [diff] [blame] | 480 | * sget_fc - Find or create a superblock |
| 481 | * @fc: Filesystem context. |
| 482 | * @test: Comparison callback |
| 483 | * @set: Setup callback |
| 484 | * |
| 485 | * Find or create a superblock using the parameters stored in the filesystem |
| 486 | * context and the two callback functions. |
| 487 | * |
| 488 | * If an extant superblock is matched, then that will be returned with an |
| 489 | * elevated reference count that the caller must transfer or discard. |
| 490 | * |
| 491 | * If no match is made, a new superblock will be allocated and basic |
| 492 | * initialisation will be performed (s_type, s_fs_info and s_id will be set and |
| 493 | * the set() callback will be invoked), the superblock will be published and it |
| 494 | * will be returned in a partially constructed state with SB_BORN and SB_ACTIVE |
| 495 | * as yet unset. |
| 496 | */ |
| 497 | struct super_block *sget_fc(struct fs_context *fc, |
| 498 | int (*test)(struct super_block *, struct fs_context *), |
| 499 | int (*set)(struct super_block *, struct fs_context *)) |
| 500 | { |
| 501 | struct super_block *s = NULL; |
| 502 | struct super_block *old; |
| 503 | struct user_namespace *user_ns = fc->global ? &init_user_ns : fc->user_ns; |
| 504 | int err; |
| 505 | |
| 506 | if (!(fc->sb_flags & SB_KERNMOUNT) && |
| 507 | fc->purpose != FS_CONTEXT_FOR_SUBMOUNT) { |
| 508 | /* Don't allow mounting unless the caller has CAP_SYS_ADMIN |
| 509 | * over the namespace. |
| 510 | */ |
| 511 | if (!(fc->fs_type->fs_flags & FS_USERNS_MOUNT)) { |
| 512 | if (!capable(CAP_SYS_ADMIN)) |
| 513 | return ERR_PTR(-EPERM); |
| 514 | } else { |
| 515 | if (!ns_capable(fc->user_ns, CAP_SYS_ADMIN)) |
| 516 | return ERR_PTR(-EPERM); |
| 517 | } |
| 518 | } |
| 519 | |
| 520 | retry: |
| 521 | spin_lock(&sb_lock); |
| 522 | if (test) { |
| 523 | hlist_for_each_entry(old, &fc->fs_type->fs_supers, s_instances) { |
| 524 | if (test(old, fc)) |
| 525 | goto share_extant_sb; |
| 526 | } |
| 527 | } |
| 528 | if (!s) { |
| 529 | spin_unlock(&sb_lock); |
| 530 | s = alloc_super(fc->fs_type, fc->sb_flags, user_ns); |
| 531 | if (!s) |
| 532 | return ERR_PTR(-ENOMEM); |
| 533 | goto retry; |
| 534 | } |
| 535 | |
| 536 | s->s_fs_info = fc->s_fs_info; |
| 537 | err = set(s, fc); |
| 538 | if (err) { |
| 539 | s->s_fs_info = NULL; |
| 540 | spin_unlock(&sb_lock); |
| 541 | destroy_unused_super(s); |
| 542 | return ERR_PTR(err); |
| 543 | } |
| 544 | fc->s_fs_info = NULL; |
| 545 | s->s_type = fc->fs_type; |
| 546 | strlcpy(s->s_id, s->s_type->name, sizeof(s->s_id)); |
| 547 | list_add_tail(&s->s_list, &super_blocks); |
| 548 | hlist_add_head(&s->s_instances, &s->s_type->fs_supers); |
| 549 | spin_unlock(&sb_lock); |
| 550 | get_filesystem(s->s_type); |
| 551 | register_shrinker_prepared(&s->s_shrink); |
| 552 | return s; |
| 553 | |
| 554 | share_extant_sb: |
| 555 | if (user_ns != old->s_user_ns) { |
| 556 | spin_unlock(&sb_lock); |
| 557 | destroy_unused_super(s); |
| 558 | return ERR_PTR(-EBUSY); |
| 559 | } |
| 560 | if (!grab_super(old)) |
| 561 | goto retry; |
| 562 | destroy_unused_super(s); |
| 563 | return old; |
| 564 | } |
| 565 | EXPORT_SYMBOL(sget_fc); |
| 566 | |
| 567 | /** |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 568 | * sget_userns - find or create a superblock |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 569 | * @type: filesystem type superblock should belong to |
| 570 | * @test: comparison callback |
| 571 | * @set: setup callback |
David Howells | 9249e17 | 2012-06-25 12:55:37 +0100 | [diff] [blame] | 572 | * @flags: mount flags |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 573 | * @user_ns: User namespace for the super_block |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 574 | * @data: argument to each of them |
| 575 | */ |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 576 | struct super_block *sget_userns(struct file_system_type *type, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 577 | int (*test)(struct super_block *,void *), |
| 578 | int (*set)(struct super_block *,void *), |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 579 | int flags, struct user_namespace *user_ns, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 580 | void *data) |
| 581 | { |
| 582 | struct super_block *s = NULL; |
Matthias Kaehlcke | d473012 | 2007-10-18 23:39:57 -0700 | [diff] [blame] | 583 | struct super_block *old; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 584 | int err; |
| 585 | |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 586 | if (!(flags & (SB_KERNMOUNT|SB_SUBMOUNT)) && |
Eric W. Biederman | a001e74 | 2016-06-06 15:48:04 -0500 | [diff] [blame] | 587 | !(type->fs_flags & FS_USERNS_MOUNT) && |
| 588 | !capable(CAP_SYS_ADMIN)) |
| 589 | return ERR_PTR(-EPERM); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 590 | retry: |
| 591 | spin_lock(&sb_lock); |
Matthias Kaehlcke | d473012 | 2007-10-18 23:39:57 -0700 | [diff] [blame] | 592 | if (test) { |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 593 | hlist_for_each_entry(old, &type->fs_supers, s_instances) { |
Matthias Kaehlcke | d473012 | 2007-10-18 23:39:57 -0700 | [diff] [blame] | 594 | if (!test(old, data)) |
| 595 | continue; |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 596 | if (user_ns != old->s_user_ns) { |
| 597 | spin_unlock(&sb_lock); |
Al Viro | 0200894 | 2017-10-11 13:48:55 -0400 | [diff] [blame] | 598 | destroy_unused_super(s); |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 599 | return ERR_PTR(-EBUSY); |
| 600 | } |
Matthias Kaehlcke | d473012 | 2007-10-18 23:39:57 -0700 | [diff] [blame] | 601 | if (!grab_super(old)) |
| 602 | goto retry; |
Al Viro | 0200894 | 2017-10-11 13:48:55 -0400 | [diff] [blame] | 603 | destroy_unused_super(s); |
Matthias Kaehlcke | d473012 | 2007-10-18 23:39:57 -0700 | [diff] [blame] | 604 | return old; |
| 605 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 606 | } |
| 607 | if (!s) { |
| 608 | spin_unlock(&sb_lock); |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 609 | s = alloc_super(type, (flags & ~SB_SUBMOUNT), user_ns); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 610 | if (!s) |
| 611 | return ERR_PTR(-ENOMEM); |
| 612 | goto retry; |
| 613 | } |
David Howells | dd111b3 | 2017-07-04 17:25:09 +0100 | [diff] [blame] | 614 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 615 | err = set(s, data); |
| 616 | if (err) { |
| 617 | spin_unlock(&sb_lock); |
Al Viro | 0200894 | 2017-10-11 13:48:55 -0400 | [diff] [blame] | 618 | destroy_unused_super(s); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 619 | return ERR_PTR(err); |
| 620 | } |
| 621 | s->s_type = type; |
| 622 | strlcpy(s->s_id, type->name, sizeof(s->s_id)); |
| 623 | list_add_tail(&s->s_list, &super_blocks); |
Al Viro | a516616 | 2011-12-12 22:53:00 -0500 | [diff] [blame] | 624 | hlist_add_head(&s->s_instances, &type->fs_supers); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 625 | spin_unlock(&sb_lock); |
| 626 | get_filesystem(type); |
Tetsuo Handa | 8e04944 | 2018-04-04 19:53:07 +0900 | [diff] [blame] | 627 | register_shrinker_prepared(&s->s_shrink); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 628 | return s; |
| 629 | } |
| 630 | |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 631 | EXPORT_SYMBOL(sget_userns); |
| 632 | |
| 633 | /** |
| 634 | * sget - find or create a superblock |
| 635 | * @type: filesystem type superblock should belong to |
| 636 | * @test: comparison callback |
| 637 | * @set: setup callback |
| 638 | * @flags: mount flags |
| 639 | * @data: argument to each of them |
| 640 | */ |
| 641 | struct super_block *sget(struct file_system_type *type, |
| 642 | int (*test)(struct super_block *,void *), |
| 643 | int (*set)(struct super_block *,void *), |
| 644 | int flags, |
| 645 | void *data) |
| 646 | { |
| 647 | struct user_namespace *user_ns = current_user_ns(); |
| 648 | |
Eric W. Biederman | 93faccbb | 2017-02-01 06:06:16 +1300 | [diff] [blame] | 649 | /* We don't yet pass the user namespace of the parent |
| 650 | * mount through to here so always use &init_user_ns |
| 651 | * until that changes. |
| 652 | */ |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 653 | if (flags & SB_SUBMOUNT) |
Eric W. Biederman | 93faccbb | 2017-02-01 06:06:16 +1300 | [diff] [blame] | 654 | user_ns = &init_user_ns; |
| 655 | |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 656 | /* Ensure the requestor has permissions over the target filesystem */ |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 657 | 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] | 658 | return ERR_PTR(-EPERM); |
| 659 | |
| 660 | return sget_userns(type, test, set, flags, user_ns, data); |
| 661 | } |
| 662 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 663 | EXPORT_SYMBOL(sget); |
| 664 | |
| 665 | void drop_super(struct super_block *sb) |
| 666 | { |
| 667 | up_read(&sb->s_umount); |
| 668 | put_super(sb); |
| 669 | } |
| 670 | |
| 671 | EXPORT_SYMBOL(drop_super); |
| 672 | |
Jan Kara | ba6379f | 2016-11-23 12:53:00 +0100 | [diff] [blame] | 673 | void drop_super_exclusive(struct super_block *sb) |
| 674 | { |
| 675 | up_write(&sb->s_umount); |
| 676 | put_super(sb); |
| 677 | } |
| 678 | EXPORT_SYMBOL(drop_super_exclusive); |
| 679 | |
Mateusz Guzik | fa7c1d5 | 2017-10-03 18:17:40 +0200 | [diff] [blame] | 680 | static void __iterate_supers(void (*f)(struct super_block *)) |
| 681 | { |
| 682 | struct super_block *sb, *p = NULL; |
| 683 | |
| 684 | spin_lock(&sb_lock); |
| 685 | list_for_each_entry(sb, &super_blocks, s_list) { |
| 686 | if (hlist_unhashed(&sb->s_instances)) |
| 687 | continue; |
| 688 | sb->s_count++; |
| 689 | spin_unlock(&sb_lock); |
| 690 | |
| 691 | f(sb); |
| 692 | |
| 693 | spin_lock(&sb_lock); |
| 694 | if (p) |
| 695 | __put_super(p); |
| 696 | p = sb; |
| 697 | } |
| 698 | if (p) |
| 699 | __put_super(p); |
| 700 | spin_unlock(&sb_lock); |
| 701 | } |
Christoph Hellwig | e500475 | 2009-05-05 16:08:56 +0200 | [diff] [blame] | 702 | /** |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 703 | * iterate_supers - call function for all active superblocks |
| 704 | * @f: function to call |
| 705 | * @arg: argument to pass to it |
| 706 | * |
| 707 | * Scans the superblock list and calls given function, passing it |
| 708 | * locked superblock and given argument. |
| 709 | */ |
| 710 | void iterate_supers(void (*f)(struct super_block *, void *), void *arg) |
| 711 | { |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 712 | struct super_block *sb, *p = NULL; |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 713 | |
| 714 | spin_lock(&sb_lock); |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 715 | list_for_each_entry(sb, &super_blocks, s_list) { |
Al Viro | a516616 | 2011-12-12 22:53:00 -0500 | [diff] [blame] | 716 | if (hlist_unhashed(&sb->s_instances)) |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 717 | continue; |
| 718 | sb->s_count++; |
| 719 | spin_unlock(&sb_lock); |
| 720 | |
| 721 | down_read(&sb->s_umount); |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 722 | if (sb->s_root && (sb->s_flags & SB_BORN)) |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 723 | f(sb, arg); |
| 724 | up_read(&sb->s_umount); |
| 725 | |
| 726 | spin_lock(&sb_lock); |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 727 | if (p) |
| 728 | __put_super(p); |
| 729 | p = sb; |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 730 | } |
Al Viro | dca3325 | 2010-07-25 02:31:46 +0400 | [diff] [blame] | 731 | if (p) |
| 732 | __put_super(p); |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 733 | spin_unlock(&sb_lock); |
| 734 | } |
| 735 | |
| 736 | /** |
Al Viro | 43e15cd | 2011-06-03 20:16:57 -0400 | [diff] [blame] | 737 | * iterate_supers_type - call function for superblocks of given type |
| 738 | * @type: fs type |
| 739 | * @f: function to call |
| 740 | * @arg: argument to pass to it |
| 741 | * |
| 742 | * Scans the superblock list and calls given function, passing it |
| 743 | * locked superblock and given argument. |
| 744 | */ |
| 745 | void iterate_supers_type(struct file_system_type *type, |
| 746 | void (*f)(struct super_block *, void *), void *arg) |
| 747 | { |
| 748 | struct super_block *sb, *p = NULL; |
| 749 | |
| 750 | spin_lock(&sb_lock); |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 751 | hlist_for_each_entry(sb, &type->fs_supers, s_instances) { |
Al Viro | 43e15cd | 2011-06-03 20:16:57 -0400 | [diff] [blame] | 752 | sb->s_count++; |
| 753 | spin_unlock(&sb_lock); |
| 754 | |
| 755 | down_read(&sb->s_umount); |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 756 | if (sb->s_root && (sb->s_flags & SB_BORN)) |
Al Viro | 43e15cd | 2011-06-03 20:16:57 -0400 | [diff] [blame] | 757 | f(sb, arg); |
| 758 | up_read(&sb->s_umount); |
| 759 | |
| 760 | spin_lock(&sb_lock); |
| 761 | if (p) |
| 762 | __put_super(p); |
| 763 | p = sb; |
| 764 | } |
| 765 | if (p) |
| 766 | __put_super(p); |
| 767 | spin_unlock(&sb_lock); |
| 768 | } |
| 769 | |
| 770 | EXPORT_SYMBOL(iterate_supers_type); |
| 771 | |
Jan Kara | ba6379f | 2016-11-23 12:53:00 +0100 | [diff] [blame] | 772 | static struct super_block *__get_super(struct block_device *bdev, bool excl) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 773 | { |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 774 | struct super_block *sb; |
| 775 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 776 | if (!bdev) |
| 777 | return NULL; |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 778 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 779 | spin_lock(&sb_lock); |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 780 | rescan: |
| 781 | list_for_each_entry(sb, &super_blocks, s_list) { |
Al Viro | a516616 | 2011-12-12 22:53:00 -0500 | [diff] [blame] | 782 | if (hlist_unhashed(&sb->s_instances)) |
Al Viro | 551de6f | 2010-03-22 19:36:35 -0400 | [diff] [blame] | 783 | continue; |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 784 | if (sb->s_bdev == bdev) { |
| 785 | sb->s_count++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 786 | spin_unlock(&sb_lock); |
Jan Kara | ba6379f | 2016-11-23 12:53:00 +0100 | [diff] [blame] | 787 | if (!excl) |
| 788 | down_read(&sb->s_umount); |
| 789 | else |
| 790 | down_write(&sb->s_umount); |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 791 | /* still alive? */ |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 792 | if (sb->s_root && (sb->s_flags & SB_BORN)) |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 793 | return sb; |
Jan Kara | ba6379f | 2016-11-23 12:53:00 +0100 | [diff] [blame] | 794 | if (!excl) |
| 795 | up_read(&sb->s_umount); |
| 796 | else |
| 797 | up_write(&sb->s_umount); |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 798 | /* nope, got unmounted */ |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 799 | spin_lock(&sb_lock); |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 800 | __put_super(sb); |
| 801 | goto rescan; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 802 | } |
| 803 | } |
| 804 | spin_unlock(&sb_lock); |
| 805 | return NULL; |
| 806 | } |
| 807 | |
Jan Kara | ba6379f | 2016-11-23 12:53:00 +0100 | [diff] [blame] | 808 | /** |
| 809 | * get_super - get the superblock of a device |
| 810 | * @bdev: device to get the superblock for |
| 811 | * |
| 812 | * Scans the superblock list and finds the superblock of the file system |
| 813 | * mounted on the device given. %NULL is returned if no match is found. |
| 814 | */ |
| 815 | struct super_block *get_super(struct block_device *bdev) |
| 816 | { |
| 817 | return __get_super(bdev, false); |
| 818 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 819 | EXPORT_SYMBOL(get_super); |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 820 | |
Jan Kara | ba6379f | 2016-11-23 12:53:00 +0100 | [diff] [blame] | 821 | static struct super_block *__get_super_thawed(struct block_device *bdev, |
| 822 | bool excl) |
| 823 | { |
| 824 | while (1) { |
| 825 | struct super_block *s = __get_super(bdev, excl); |
| 826 | if (!s || s->s_writers.frozen == SB_UNFROZEN) |
| 827 | return s; |
| 828 | if (!excl) |
| 829 | up_read(&s->s_umount); |
| 830 | else |
| 831 | up_write(&s->s_umount); |
| 832 | wait_event(s->s_writers.wait_unfrozen, |
| 833 | s->s_writers.frozen == SB_UNFROZEN); |
| 834 | put_super(s); |
| 835 | } |
| 836 | } |
| 837 | |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 838 | /** |
Jan Kara | 6b6dc83 | 2012-02-10 11:03:00 +0100 | [diff] [blame] | 839 | * get_super_thawed - get thawed superblock of a device |
| 840 | * @bdev: device to get the superblock for |
| 841 | * |
| 842 | * Scans the superblock list and finds the superblock of the file system |
| 843 | * mounted on the device. The superblock is returned once it is thawed |
| 844 | * (or immediately if it was not frozen). %NULL is returned if no match |
| 845 | * is found. |
| 846 | */ |
| 847 | struct super_block *get_super_thawed(struct block_device *bdev) |
| 848 | { |
Jan Kara | ba6379f | 2016-11-23 12:53:00 +0100 | [diff] [blame] | 849 | return __get_super_thawed(bdev, false); |
Jan Kara | 6b6dc83 | 2012-02-10 11:03:00 +0100 | [diff] [blame] | 850 | } |
| 851 | EXPORT_SYMBOL(get_super_thawed); |
| 852 | |
| 853 | /** |
Jan Kara | ba6379f | 2016-11-23 12:53:00 +0100 | [diff] [blame] | 854 | * get_super_exclusive_thawed - get thawed superblock of a device |
| 855 | * @bdev: device to get the superblock for |
| 856 | * |
| 857 | * Scans the superblock list and finds the superblock of the file system |
| 858 | * mounted on the device. The superblock is returned once it is thawed |
| 859 | * (or immediately if it was not frozen) and s_umount semaphore is held |
| 860 | * in exclusive mode. %NULL is returned if no match is found. |
| 861 | */ |
| 862 | struct super_block *get_super_exclusive_thawed(struct block_device *bdev) |
| 863 | { |
| 864 | return __get_super_thawed(bdev, true); |
| 865 | } |
| 866 | EXPORT_SYMBOL(get_super_exclusive_thawed); |
| 867 | |
| 868 | /** |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 869 | * get_active_super - get an active reference to the superblock of a device |
| 870 | * @bdev: device to get the superblock for |
| 871 | * |
| 872 | * Scans the superblock list and finds the superblock of the file system |
| 873 | * mounted on the device given. Returns the superblock with an active |
Al Viro | d3f2147 | 2010-03-23 11:11:05 -0400 | [diff] [blame] | 874 | * reference or %NULL if none was found. |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 875 | */ |
| 876 | struct super_block *get_active_super(struct block_device *bdev) |
| 877 | { |
| 878 | struct super_block *sb; |
| 879 | |
| 880 | if (!bdev) |
| 881 | return NULL; |
| 882 | |
Al Viro | 1494583 | 2010-03-22 20:15:33 -0400 | [diff] [blame] | 883 | restart: |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 884 | spin_lock(&sb_lock); |
| 885 | list_for_each_entry(sb, &super_blocks, s_list) { |
Al Viro | a516616 | 2011-12-12 22:53:00 -0500 | [diff] [blame] | 886 | if (hlist_unhashed(&sb->s_instances)) |
Al Viro | 551de6f | 2010-03-22 19:36:35 -0400 | [diff] [blame] | 887 | continue; |
Al Viro | 1494583 | 2010-03-22 20:15:33 -0400 | [diff] [blame] | 888 | if (sb->s_bdev == bdev) { |
Al Viro | acfec9a | 2013-07-20 03:13:55 +0400 | [diff] [blame] | 889 | if (!grab_super(sb)) |
Al Viro | 1494583 | 2010-03-22 20:15:33 -0400 | [diff] [blame] | 890 | goto restart; |
Al Viro | acfec9a | 2013-07-20 03:13:55 +0400 | [diff] [blame] | 891 | up_write(&sb->s_umount); |
| 892 | return sb; |
Al Viro | 1494583 | 2010-03-22 20:15:33 -0400 | [diff] [blame] | 893 | } |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 894 | } |
| 895 | spin_unlock(&sb_lock); |
| 896 | return NULL; |
| 897 | } |
David Howells | dd111b3 | 2017-07-04 17:25:09 +0100 | [diff] [blame] | 898 | |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 899 | struct super_block *user_get_super(dev_t dev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 900 | { |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 901 | struct super_block *sb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 902 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 903 | spin_lock(&sb_lock); |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 904 | rescan: |
| 905 | list_for_each_entry(sb, &super_blocks, s_list) { |
Al Viro | a516616 | 2011-12-12 22:53:00 -0500 | [diff] [blame] | 906 | if (hlist_unhashed(&sb->s_instances)) |
Al Viro | 551de6f | 2010-03-22 19:36:35 -0400 | [diff] [blame] | 907 | continue; |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 908 | if (sb->s_dev == dev) { |
| 909 | sb->s_count++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 910 | spin_unlock(&sb_lock); |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 911 | down_read(&sb->s_umount); |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 912 | /* still alive? */ |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 913 | if (sb->s_root && (sb->s_flags & SB_BORN)) |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 914 | return sb; |
| 915 | up_read(&sb->s_umount); |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 916 | /* nope, got unmounted */ |
Kirill Korotaev | 618f063 | 2005-06-23 00:09:54 -0700 | [diff] [blame] | 917 | spin_lock(&sb_lock); |
Al Viro | df40c01 | 2010-03-22 20:23:25 -0400 | [diff] [blame] | 918 | __put_super(sb); |
| 919 | goto rescan; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 920 | } |
| 921 | } |
| 922 | spin_unlock(&sb_lock); |
| 923 | return NULL; |
| 924 | } |
| 925 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 926 | /** |
David Howells | 8d0347f | 2018-11-04 09:28:36 -0500 | [diff] [blame] | 927 | * reconfigure_super - asks filesystem to change superblock parameters |
| 928 | * @fc: The superblock and configuration |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 929 | * |
David Howells | 8d0347f | 2018-11-04 09:28:36 -0500 | [diff] [blame] | 930 | * Alters the configuration parameters of a live superblock. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 931 | */ |
David Howells | 8d0347f | 2018-11-04 09:28:36 -0500 | [diff] [blame] | 932 | int reconfigure_super(struct fs_context *fc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 933 | { |
David Howells | 8d0347f | 2018-11-04 09:28:36 -0500 | [diff] [blame] | 934 | struct super_block *sb = fc->root->d_sb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 935 | int retval; |
David Howells | 8d0347f | 2018-11-04 09:28:36 -0500 | [diff] [blame] | 936 | bool remount_ro = false; |
| 937 | bool force = fc->sb_flags & SB_FORCE; |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 938 | |
David Howells | 8d0347f | 2018-11-04 09:28:36 -0500 | [diff] [blame] | 939 | if (fc->sb_flags_mask & ~MS_RMT_MASK) |
| 940 | return -EINVAL; |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 941 | if (sb->s_writers.frozen != SB_UNFROZEN) |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 942 | return -EBUSY; |
| 943 | |
David Howells | 8d0347f | 2018-11-04 09:28:36 -0500 | [diff] [blame] | 944 | retval = security_sb_remount(sb, fc->security); |
| 945 | if (retval) |
| 946 | return retval; |
| 947 | |
| 948 | if (fc->sb_flags_mask & SB_RDONLY) { |
David Howells | 9361401 | 2006-09-30 20:45:40 +0200 | [diff] [blame] | 949 | #ifdef CONFIG_BLOCK |
David Howells | 8d0347f | 2018-11-04 09:28:36 -0500 | [diff] [blame] | 950 | if (!(fc->sb_flags & SB_RDONLY) && bdev_read_only(sb->s_bdev)) |
| 951 | return -EACCES; |
David Howells | 9361401 | 2006-09-30 20:45:40 +0200 | [diff] [blame] | 952 | #endif |
Christoph Hellwig | 4504230 | 2009-08-03 23:28:35 +0200 | [diff] [blame] | 953 | |
David Howells | 8d0347f | 2018-11-04 09:28:36 -0500 | [diff] [blame] | 954 | remount_ro = (fc->sb_flags & SB_RDONLY) && !sb_rdonly(sb); |
| 955 | } |
Nick Piggin | d208bbd | 2009-12-21 16:28:53 -0800 | [diff] [blame] | 956 | |
Al Viro | 0aec09d | 2014-08-07 07:32:06 -0400 | [diff] [blame] | 957 | if (remount_ro) { |
Al Viro | fdab684 | 2015-01-11 10:57:27 -0500 | [diff] [blame] | 958 | if (!hlist_empty(&sb->s_pins)) { |
Al Viro | 0aec09d | 2014-08-07 07:32:06 -0400 | [diff] [blame] | 959 | up_write(&sb->s_umount); |
Al Viro | fdab684 | 2015-01-11 10:57:27 -0500 | [diff] [blame] | 960 | group_pin_kill(&sb->s_pins); |
Al Viro | 0aec09d | 2014-08-07 07:32:06 -0400 | [diff] [blame] | 961 | down_write(&sb->s_umount); |
| 962 | if (!sb->s_root) |
| 963 | return 0; |
| 964 | if (sb->s_writers.frozen != SB_UNFROZEN) |
| 965 | return -EBUSY; |
David Howells | 8d0347f | 2018-11-04 09:28:36 -0500 | [diff] [blame] | 966 | remount_ro = !sb_rdonly(sb); |
Al Viro | 0aec09d | 2014-08-07 07:32:06 -0400 | [diff] [blame] | 967 | } |
| 968 | } |
| 969 | shrink_dcache_sb(sb); |
| 970 | |
David Howells | 8d0347f | 2018-11-04 09:28:36 -0500 | [diff] [blame] | 971 | /* If we are reconfiguring to RDONLY and current sb is read/write, |
| 972 | * make sure there are no files open for writing. |
| 973 | */ |
Nick Piggin | d208bbd | 2009-12-21 16:28:53 -0800 | [diff] [blame] | 974 | if (remount_ro) { |
Miklos Szeredi | 4ed5e82f | 2011-11-21 12:11:31 +0100 | [diff] [blame] | 975 | if (force) { |
Al Viro | eee5cc2 | 2013-10-04 11:06:42 -0400 | [diff] [blame] | 976 | sb->s_readonly_remount = 1; |
| 977 | smp_wmb(); |
Miklos Szeredi | 4ed5e82f | 2011-11-21 12:11:31 +0100 | [diff] [blame] | 978 | } else { |
| 979 | retval = sb_prepare_remount_readonly(sb); |
| 980 | if (retval) |
| 981 | return retval; |
Miklos Szeredi | 4ed5e82f | 2011-11-21 12:11:31 +0100 | [diff] [blame] | 982 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 983 | } |
| 984 | |
Al Viro | f3a09c9 | 2018-12-23 18:55:56 -0500 | [diff] [blame] | 985 | if (fc->ops->reconfigure) { |
| 986 | retval = fc->ops->reconfigure(fc); |
| 987 | if (retval) { |
| 988 | if (!force) |
| 989 | goto cancel_readonly; |
| 990 | /* If forced remount, go ahead despite any errors */ |
| 991 | WARN(1, "forced remount of a %s fs returned %i\n", |
| 992 | sb->s_type->name, retval); |
| 993 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 994 | } |
David Howells | 8d0347f | 2018-11-04 09:28:36 -0500 | [diff] [blame] | 995 | |
| 996 | WRITE_ONCE(sb->s_flags, ((sb->s_flags & ~fc->sb_flags_mask) | |
| 997 | (fc->sb_flags & fc->sb_flags_mask))); |
Miklos Szeredi | 4ed5e82f | 2011-11-21 12:11:31 +0100 | [diff] [blame] | 998 | /* Needs to be ordered wrt mnt_is_readonly() */ |
| 999 | smp_wmb(); |
| 1000 | sb->s_readonly_remount = 0; |
Christoph Hellwig | c79d967 | 2010-05-19 07:16:40 -0400 | [diff] [blame] | 1001 | |
Nick Piggin | d208bbd | 2009-12-21 16:28:53 -0800 | [diff] [blame] | 1002 | /* |
| 1003 | * Some filesystems modify their metadata via some other path than the |
| 1004 | * bdev buffer cache (eg. use a private mapping, or directories in |
| 1005 | * pagecache, etc). Also file data modifications go via their own |
| 1006 | * mappings. So If we try to mount readonly then copy the filesystem |
| 1007 | * from bdev, we could get stale data, so invalidate it to give a best |
| 1008 | * effort at coherency. |
| 1009 | */ |
| 1010 | if (remount_ro && sb->s_bdev) |
| 1011 | invalidate_bdev(sb->s_bdev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1012 | return 0; |
Miklos Szeredi | 4ed5e82f | 2011-11-21 12:11:31 +0100 | [diff] [blame] | 1013 | |
| 1014 | cancel_readonly: |
| 1015 | sb->s_readonly_remount = 0; |
| 1016 | return retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1017 | } |
| 1018 | |
Mateusz Guzik | fa7c1d5 | 2017-10-03 18:17:40 +0200 | [diff] [blame] | 1019 | static void do_emergency_remount_callback(struct super_block *sb) |
| 1020 | { |
| 1021 | down_write(&sb->s_umount); |
| 1022 | if (sb->s_root && sb->s_bdev && (sb->s_flags & SB_BORN) && |
| 1023 | !sb_rdonly(sb)) { |
David Howells | 8d0347f | 2018-11-04 09:28:36 -0500 | [diff] [blame] | 1024 | struct fs_context *fc; |
| 1025 | |
| 1026 | fc = fs_context_for_reconfigure(sb->s_root, |
| 1027 | SB_RDONLY | SB_FORCE, SB_RDONLY); |
| 1028 | if (!IS_ERR(fc)) { |
| 1029 | if (parse_monolithic_mount_data(fc, NULL) == 0) |
| 1030 | (void)reconfigure_super(fc); |
| 1031 | put_fs_context(fc); |
| 1032 | } |
Mateusz Guzik | fa7c1d5 | 2017-10-03 18:17:40 +0200 | [diff] [blame] | 1033 | } |
| 1034 | up_write(&sb->s_umount); |
| 1035 | } |
| 1036 | |
Jens Axboe | a2a9537 | 2009-03-17 09:38:40 +0100 | [diff] [blame] | 1037 | static void do_emergency_remount(struct work_struct *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1038 | { |
Mateusz Guzik | fa7c1d5 | 2017-10-03 18:17:40 +0200 | [diff] [blame] | 1039 | __iterate_supers(do_emergency_remount_callback); |
Jens Axboe | a2a9537 | 2009-03-17 09:38:40 +0100 | [diff] [blame] | 1040 | kfree(work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1041 | printk("Emergency Remount complete\n"); |
| 1042 | } |
| 1043 | |
| 1044 | void emergency_remount(void) |
| 1045 | { |
Jens Axboe | a2a9537 | 2009-03-17 09:38:40 +0100 | [diff] [blame] | 1046 | struct work_struct *work; |
| 1047 | |
| 1048 | work = kmalloc(sizeof(*work), GFP_ATOMIC); |
| 1049 | if (work) { |
| 1050 | INIT_WORK(work, do_emergency_remount); |
| 1051 | schedule_work(work); |
| 1052 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1053 | } |
| 1054 | |
Mateusz Guzik | 08fdc8a | 2017-10-03 18:17:41 +0200 | [diff] [blame] | 1055 | static void do_thaw_all_callback(struct super_block *sb) |
| 1056 | { |
| 1057 | down_write(&sb->s_umount); |
Al Viro | 1c18d2a | 2018-05-10 15:09:41 -0400 | [diff] [blame] | 1058 | if (sb->s_root && sb->s_flags & SB_BORN) { |
Mateusz Guzik | 08fdc8a | 2017-10-03 18:17:41 +0200 | [diff] [blame] | 1059 | emergency_thaw_bdev(sb); |
| 1060 | thaw_super_locked(sb); |
| 1061 | } else { |
| 1062 | up_write(&sb->s_umount); |
| 1063 | } |
| 1064 | } |
| 1065 | |
| 1066 | static void do_thaw_all(struct work_struct *work) |
| 1067 | { |
| 1068 | __iterate_supers(do_thaw_all_callback); |
| 1069 | kfree(work); |
| 1070 | printk(KERN_WARNING "Emergency Thaw complete\n"); |
| 1071 | } |
| 1072 | |
| 1073 | /** |
| 1074 | * emergency_thaw_all -- forcibly thaw every frozen filesystem |
| 1075 | * |
| 1076 | * Used for emergency unfreeze of all filesystems via SysRq |
| 1077 | */ |
| 1078 | void emergency_thaw_all(void) |
| 1079 | { |
| 1080 | struct work_struct *work; |
| 1081 | |
| 1082 | work = kmalloc(sizeof(*work), GFP_ATOMIC); |
| 1083 | if (work) { |
| 1084 | INIT_WORK(work, do_thaw_all); |
| 1085 | schedule_work(work); |
| 1086 | } |
| 1087 | } |
| 1088 | |
Alexey Dobriyan | ad76cbc | 2008-08-28 06:26:23 +0400 | [diff] [blame] | 1089 | static DEFINE_IDA(unnamed_dev_ida); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1090 | |
Matthew Wilcox | 5a66847 | 2018-06-11 12:03:31 -0400 | [diff] [blame] | 1091 | /** |
| 1092 | * get_anon_bdev - Allocate a block device for filesystems which don't have one. |
| 1093 | * @p: Pointer to a dev_t. |
| 1094 | * |
| 1095 | * Filesystems which don't use real block devices can call this function |
| 1096 | * to allocate a virtual block device. |
| 1097 | * |
| 1098 | * Context: Any context. Frequently called while holding sb_lock. |
| 1099 | * Return: 0 on success, -EMFILE if there are no anonymous bdevs left |
| 1100 | * or -ENOMEM if memory allocation failed. |
| 1101 | */ |
Al Viro | 0ee5dc6 | 2011-07-07 15:44:25 -0400 | [diff] [blame] | 1102 | int get_anon_bdev(dev_t *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1103 | { |
| 1104 | int dev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1105 | |
Matthew Wilcox | 5a66847 | 2018-06-11 12:03:31 -0400 | [diff] [blame] | 1106 | /* |
| 1107 | * Many userspace utilities consider an FSID of 0 invalid. |
| 1108 | * Always return at least 1 from get_anon_bdev. |
| 1109 | */ |
| 1110 | dev = ida_alloc_range(&unnamed_dev_ida, 1, (1 << MINORBITS) - 1, |
| 1111 | GFP_ATOMIC); |
| 1112 | if (dev == -ENOSPC) |
| 1113 | dev = -EMFILE; |
| 1114 | if (dev < 0) |
| 1115 | return dev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1116 | |
Matthew Wilcox | 5a66847 | 2018-06-11 12:03:31 -0400 | [diff] [blame] | 1117 | *p = MKDEV(0, dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1118 | return 0; |
| 1119 | } |
Al Viro | 0ee5dc6 | 2011-07-07 15:44:25 -0400 | [diff] [blame] | 1120 | EXPORT_SYMBOL(get_anon_bdev); |
| 1121 | |
| 1122 | void free_anon_bdev(dev_t dev) |
| 1123 | { |
Matthew Wilcox | 5a66847 | 2018-06-11 12:03:31 -0400 | [diff] [blame] | 1124 | ida_free(&unnamed_dev_ida, MINOR(dev)); |
Al Viro | 0ee5dc6 | 2011-07-07 15:44:25 -0400 | [diff] [blame] | 1125 | } |
| 1126 | EXPORT_SYMBOL(free_anon_bdev); |
| 1127 | |
| 1128 | int set_anon_super(struct super_block *s, void *data) |
| 1129 | { |
Christoph Hellwig | df0ce26 | 2015-01-14 10:42:41 +0100 | [diff] [blame] | 1130 | return get_anon_bdev(&s->s_dev); |
Al Viro | 0ee5dc6 | 2011-07-07 15:44:25 -0400 | [diff] [blame] | 1131 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1132 | EXPORT_SYMBOL(set_anon_super); |
| 1133 | |
| 1134 | void kill_anon_super(struct super_block *sb) |
| 1135 | { |
Al Viro | 0ee5dc6 | 2011-07-07 15:44:25 -0400 | [diff] [blame] | 1136 | dev_t dev = sb->s_dev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1137 | generic_shutdown_super(sb); |
Al Viro | 0ee5dc6 | 2011-07-07 15:44:25 -0400 | [diff] [blame] | 1138 | free_anon_bdev(dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1139 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1140 | EXPORT_SYMBOL(kill_anon_super); |
| 1141 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1142 | void kill_litter_super(struct super_block *sb) |
| 1143 | { |
| 1144 | if (sb->s_root) |
| 1145 | d_genocide(sb->s_root); |
| 1146 | kill_anon_super(sb); |
| 1147 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1148 | EXPORT_SYMBOL(kill_litter_super); |
| 1149 | |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 1150 | static int ns_test_super(struct super_block *sb, void *data) |
| 1151 | { |
| 1152 | return sb->s_fs_info == data; |
| 1153 | } |
| 1154 | |
| 1155 | static int ns_set_super(struct super_block *sb, void *data) |
| 1156 | { |
| 1157 | sb->s_fs_info = data; |
| 1158 | return set_anon_super(sb, NULL); |
| 1159 | } |
| 1160 | |
Eric W. Biederman | d91ee87 | 2016-05-23 14:51:59 -0500 | [diff] [blame] | 1161 | struct dentry *mount_ns(struct file_system_type *fs_type, |
| 1162 | int flags, void *data, void *ns, struct user_namespace *user_ns, |
| 1163 | int (*fill_super)(struct super_block *, void *, int)) |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 1164 | { |
| 1165 | struct super_block *sb; |
| 1166 | |
Eric W. Biederman | d91ee87 | 2016-05-23 14:51:59 -0500 | [diff] [blame] | 1167 | /* Don't allow mounting unless the caller has CAP_SYS_ADMIN |
| 1168 | * over the namespace. |
| 1169 | */ |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1170 | if (!(flags & SB_KERNMOUNT) && !ns_capable(user_ns, CAP_SYS_ADMIN)) |
Eric W. Biederman | d91ee87 | 2016-05-23 14:51:59 -0500 | [diff] [blame] | 1171 | return ERR_PTR(-EPERM); |
| 1172 | |
Eric W. Biederman | 6e4eab5 | 2016-05-24 09:29:01 -0500 | [diff] [blame] | 1173 | sb = sget_userns(fs_type, ns_test_super, ns_set_super, flags, |
| 1174 | user_ns, ns); |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 1175 | if (IS_ERR(sb)) |
Al Viro | ceefda6 | 2010-07-26 13:16:50 +0400 | [diff] [blame] | 1176 | return ERR_CAST(sb); |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 1177 | |
| 1178 | if (!sb->s_root) { |
| 1179 | int err; |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1180 | err = fill_super(sb, data, flags & SB_SILENT ? 1 : 0); |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 1181 | if (err) { |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 1182 | deactivate_locked_super(sb); |
Al Viro | ceefda6 | 2010-07-26 13:16:50 +0400 | [diff] [blame] | 1183 | return ERR_PTR(err); |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 1184 | } |
| 1185 | |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1186 | sb->s_flags |= SB_ACTIVE; |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 1187 | } |
| 1188 | |
Al Viro | ceefda6 | 2010-07-26 13:16:50 +0400 | [diff] [blame] | 1189 | return dget(sb->s_root); |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 1190 | } |
| 1191 | |
Al Viro | ceefda6 | 2010-07-26 13:16:50 +0400 | [diff] [blame] | 1192 | EXPORT_SYMBOL(mount_ns); |
Serge E. Hallyn | 909e6d9 | 2009-04-06 19:01:07 -0700 | [diff] [blame] | 1193 | |
Al Viro | cb50b34 | 2018-12-23 17:25:47 -0500 | [diff] [blame] | 1194 | int set_anon_super_fc(struct super_block *sb, struct fs_context *fc) |
| 1195 | { |
| 1196 | return set_anon_super(sb, NULL); |
| 1197 | } |
| 1198 | EXPORT_SYMBOL(set_anon_super_fc); |
| 1199 | |
| 1200 | static int test_keyed_super(struct super_block *sb, struct fs_context *fc) |
| 1201 | { |
| 1202 | return sb->s_fs_info == fc->s_fs_info; |
| 1203 | } |
| 1204 | |
| 1205 | static int test_single_super(struct super_block *s, struct fs_context *fc) |
| 1206 | { |
| 1207 | return 1; |
| 1208 | } |
| 1209 | |
| 1210 | /** |
| 1211 | * vfs_get_super - Get a superblock with a search key set in s_fs_info. |
| 1212 | * @fc: The filesystem context holding the parameters |
| 1213 | * @keying: How to distinguish superblocks |
| 1214 | * @fill_super: Helper to initialise a new superblock |
| 1215 | * |
| 1216 | * Search for a superblock and create a new one if not found. The search |
| 1217 | * criterion is controlled by @keying. If the search fails, a new superblock |
| 1218 | * is created and @fill_super() is called to initialise it. |
| 1219 | * |
| 1220 | * @keying can take one of a number of values: |
| 1221 | * |
| 1222 | * (1) vfs_get_single_super - Only one superblock of this type may exist on the |
| 1223 | * system. This is typically used for special system filesystems. |
| 1224 | * |
| 1225 | * (2) vfs_get_keyed_super - Multiple superblocks may exist, but they must have |
| 1226 | * distinct keys (where the key is in s_fs_info). Searching for the same |
| 1227 | * key again will turn up the superblock for that key. |
| 1228 | * |
| 1229 | * (3) vfs_get_independent_super - Multiple superblocks may exist and are |
| 1230 | * unkeyed. Each call will get a new superblock. |
| 1231 | * |
| 1232 | * A permissions check is made by sget_fc() unless we're getting a superblock |
| 1233 | * for a kernel-internal mount or a submount. |
| 1234 | */ |
| 1235 | int vfs_get_super(struct fs_context *fc, |
| 1236 | enum vfs_get_super_keying keying, |
| 1237 | int (*fill_super)(struct super_block *sb, |
| 1238 | struct fs_context *fc)) |
| 1239 | { |
| 1240 | int (*test)(struct super_block *, struct fs_context *); |
| 1241 | struct super_block *sb; |
| 1242 | |
| 1243 | switch (keying) { |
| 1244 | case vfs_get_single_super: |
| 1245 | test = test_single_super; |
| 1246 | break; |
| 1247 | case vfs_get_keyed_super: |
| 1248 | test = test_keyed_super; |
| 1249 | break; |
| 1250 | case vfs_get_independent_super: |
| 1251 | test = NULL; |
| 1252 | break; |
| 1253 | default: |
| 1254 | BUG(); |
| 1255 | } |
| 1256 | |
| 1257 | sb = sget_fc(fc, test, set_anon_super_fc); |
| 1258 | if (IS_ERR(sb)) |
| 1259 | return PTR_ERR(sb); |
| 1260 | |
| 1261 | if (!sb->s_root) { |
| 1262 | int err = fill_super(sb, fc); |
| 1263 | if (err) { |
| 1264 | deactivate_locked_super(sb); |
| 1265 | return err; |
| 1266 | } |
| 1267 | |
| 1268 | sb->s_flags |= SB_ACTIVE; |
| 1269 | } |
| 1270 | |
| 1271 | BUG_ON(fc->root); |
| 1272 | fc->root = dget(sb->s_root); |
| 1273 | return 0; |
| 1274 | } |
| 1275 | EXPORT_SYMBOL(vfs_get_super); |
| 1276 | |
David Howells | 9361401 | 2006-09-30 20:45:40 +0200 | [diff] [blame] | 1277 | #ifdef CONFIG_BLOCK |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1278 | static int set_bdev_super(struct super_block *s, void *data) |
| 1279 | { |
| 1280 | s->s_bdev = data; |
| 1281 | s->s_dev = s->s_bdev->bd_dev; |
Jan Kara | 13eec23 | 2017-04-12 12:24:29 +0200 | [diff] [blame] | 1282 | s->s_bdi = bdi_get(s->s_bdev->bd_bdi); |
Jens Axboe | 32a88aa | 2009-09-16 15:02:33 +0200 | [diff] [blame] | 1283 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1284 | return 0; |
| 1285 | } |
| 1286 | |
| 1287 | static int test_bdev_super(struct super_block *s, void *data) |
| 1288 | { |
| 1289 | return (void *)s->s_bdev == data; |
| 1290 | } |
| 1291 | |
Al Viro | 152a083 | 2010-07-25 00:46:55 +0400 | [diff] [blame] | 1292 | struct dentry *mount_bdev(struct file_system_type *fs_type, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1293 | int flags, const char *dev_name, void *data, |
Al Viro | 152a083 | 2010-07-25 00:46:55 +0400 | [diff] [blame] | 1294 | int (*fill_super)(struct super_block *, void *, int)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1295 | { |
| 1296 | struct block_device *bdev; |
| 1297 | struct super_block *s; |
Tejun Heo | d4d7762 | 2010-11-13 11:55:18 +0100 | [diff] [blame] | 1298 | fmode_t mode = FMODE_READ | FMODE_EXCL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1299 | int error = 0; |
| 1300 | |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1301 | if (!(flags & SB_RDONLY)) |
Al Viro | 30c40d2 | 2008-02-22 19:50:45 -0500 | [diff] [blame] | 1302 | mode |= FMODE_WRITE; |
| 1303 | |
Tejun Heo | d4d7762 | 2010-11-13 11:55:18 +0100 | [diff] [blame] | 1304 | bdev = blkdev_get_by_path(dev_name, mode, fs_type); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1305 | if (IS_ERR(bdev)) |
Al Viro | 152a083 | 2010-07-25 00:46:55 +0400 | [diff] [blame] | 1306 | return ERR_CAST(bdev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1307 | |
| 1308 | /* |
| 1309 | * once the super is inserted into the list by sget, s_umount |
| 1310 | * will protect the lockfs code from trying to start a snapshot |
| 1311 | * while we are mounting |
| 1312 | */ |
Christoph Hellwig | 4fadd7b | 2009-08-03 23:28:06 +0200 | [diff] [blame] | 1313 | mutex_lock(&bdev->bd_fsfreeze_mutex); |
| 1314 | if (bdev->bd_fsfreeze_count > 0) { |
| 1315 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
| 1316 | error = -EBUSY; |
| 1317 | goto error_bdev; |
| 1318 | } |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1319 | 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] | 1320 | bdev); |
Christoph Hellwig | 4fadd7b | 2009-08-03 23:28:06 +0200 | [diff] [blame] | 1321 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1322 | if (IS_ERR(s)) |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1323 | goto error_s; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1324 | |
| 1325 | if (s->s_root) { |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1326 | if ((flags ^ s->s_flags) & SB_RDONLY) { |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 1327 | deactivate_locked_super(s); |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1328 | error = -EBUSY; |
| 1329 | goto error_bdev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1330 | } |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1331 | |
Tejun Heo | 4f331f0 | 2010-07-20 15:18:07 -0700 | [diff] [blame] | 1332 | /* |
| 1333 | * s_umount nests inside bd_mutex during |
Tejun Heo | e525fd8 | 2010-11-13 11:55:17 +0100 | [diff] [blame] | 1334 | * __invalidate_device(). blkdev_put() acquires |
| 1335 | * bd_mutex and can't be called under s_umount. Drop |
| 1336 | * s_umount temporarily. This is safe as we're |
| 1337 | * holding an active reference. |
Tejun Heo | 4f331f0 | 2010-07-20 15:18:07 -0700 | [diff] [blame] | 1338 | */ |
| 1339 | up_write(&s->s_umount); |
Tejun Heo | d4d7762 | 2010-11-13 11:55:18 +0100 | [diff] [blame] | 1340 | blkdev_put(bdev, mode); |
Tejun Heo | 4f331f0 | 2010-07-20 15:18:07 -0700 | [diff] [blame] | 1341 | down_write(&s->s_umount); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1342 | } else { |
Al Viro | 30c40d2 | 2008-02-22 19:50:45 -0500 | [diff] [blame] | 1343 | s->s_mode = mode; |
Dmitry Monakhov | a1c6f057 | 2015-04-13 16:31:37 +0400 | [diff] [blame] | 1344 | snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev); |
Pekka Enberg | e78c9a0 | 2006-01-08 01:03:39 -0800 | [diff] [blame] | 1345 | sb_set_blocksize(s, block_size(bdev)); |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1346 | error = fill_super(s, data, flags & SB_SILENT ? 1 : 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1347 | if (error) { |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 1348 | deactivate_locked_super(s); |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1349 | goto error; |
Greg Kroah-Hartman | fa67576 | 2006-02-22 09:39:02 -0800 | [diff] [blame] | 1350 | } |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1351 | |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1352 | s->s_flags |= SB_ACTIVE; |
Theodore Ts'o | 87d8fe1 | 2009-01-03 09:47:09 -0500 | [diff] [blame] | 1353 | bdev->bd_super = s; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1354 | } |
| 1355 | |
Al Viro | 152a083 | 2010-07-25 00:46:55 +0400 | [diff] [blame] | 1356 | return dget(s->s_root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1357 | |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1358 | error_s: |
| 1359 | error = PTR_ERR(s); |
| 1360 | error_bdev: |
Tejun Heo | d4d7762 | 2010-11-13 11:55:18 +0100 | [diff] [blame] | 1361 | blkdev_put(bdev, mode); |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1362 | error: |
Al Viro | 152a083 | 2010-07-25 00:46:55 +0400 | [diff] [blame] | 1363 | return ERR_PTR(error); |
| 1364 | } |
| 1365 | EXPORT_SYMBOL(mount_bdev); |
| 1366 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1367 | void kill_block_super(struct super_block *sb) |
| 1368 | { |
| 1369 | struct block_device *bdev = sb->s_bdev; |
Al Viro | 30c40d2 | 2008-02-22 19:50:45 -0500 | [diff] [blame] | 1370 | fmode_t mode = sb->s_mode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1371 | |
H Hartley Sweeten | ddbaaf3 | 2009-04-29 20:14:57 -0400 | [diff] [blame] | 1372 | bdev->bd_super = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1373 | generic_shutdown_super(sb); |
| 1374 | sync_blockdev(bdev); |
Tejun Heo | d4d7762 | 2010-11-13 11:55:18 +0100 | [diff] [blame] | 1375 | WARN_ON_ONCE(!(mode & FMODE_EXCL)); |
Tejun Heo | e525fd8 | 2010-11-13 11:55:17 +0100 | [diff] [blame] | 1376 | blkdev_put(bdev, mode | FMODE_EXCL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1377 | } |
| 1378 | |
| 1379 | EXPORT_SYMBOL(kill_block_super); |
David Howells | 9361401 | 2006-09-30 20:45:40 +0200 | [diff] [blame] | 1380 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1381 | |
Al Viro | 3c26ff6 | 2010-07-25 11:46:36 +0400 | [diff] [blame] | 1382 | struct dentry *mount_nodev(struct file_system_type *fs_type, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1383 | int flags, void *data, |
Al Viro | 3c26ff6 | 2010-07-25 11:46:36 +0400 | [diff] [blame] | 1384 | int (*fill_super)(struct super_block *, void *, int)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1385 | { |
| 1386 | int error; |
David Howells | 9249e17 | 2012-06-25 12:55:37 +0100 | [diff] [blame] | 1387 | 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] | 1388 | |
| 1389 | if (IS_ERR(s)) |
Al Viro | 3c26ff6 | 2010-07-25 11:46:36 +0400 | [diff] [blame] | 1390 | return ERR_CAST(s); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1391 | |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1392 | error = fill_super(s, data, flags & SB_SILENT ? 1 : 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1393 | if (error) { |
Al Viro | 74dbbdd | 2009-05-06 01:07:50 -0400 | [diff] [blame] | 1394 | deactivate_locked_super(s); |
Al Viro | 3c26ff6 | 2010-07-25 11:46:36 +0400 | [diff] [blame] | 1395 | return ERR_PTR(error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1396 | } |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1397 | s->s_flags |= SB_ACTIVE; |
Al Viro | 3c26ff6 | 2010-07-25 11:46:36 +0400 | [diff] [blame] | 1398 | return dget(s->s_root); |
| 1399 | } |
| 1400 | EXPORT_SYMBOL(mount_nodev); |
| 1401 | |
David Howells | 8d0347f | 2018-11-04 09:28:36 -0500 | [diff] [blame] | 1402 | static int reconfigure_single(struct super_block *s, |
| 1403 | int flags, void *data) |
| 1404 | { |
| 1405 | struct fs_context *fc; |
| 1406 | int ret; |
| 1407 | |
| 1408 | /* The caller really need to be passing fc down into mount_single(), |
| 1409 | * then a chunk of this can be removed. [Bollocks -- AV] |
| 1410 | * Better yet, reconfiguration shouldn't happen, but rather the second |
| 1411 | * mount should be rejected if the parameters are not compatible. |
| 1412 | */ |
| 1413 | fc = fs_context_for_reconfigure(s->s_root, flags, MS_RMT_MASK); |
| 1414 | if (IS_ERR(fc)) |
| 1415 | return PTR_ERR(fc); |
| 1416 | |
| 1417 | ret = parse_monolithic_mount_data(fc, data); |
| 1418 | if (ret < 0) |
| 1419 | goto out; |
| 1420 | |
| 1421 | ret = reconfigure_super(fc); |
| 1422 | out: |
| 1423 | put_fs_context(fc); |
| 1424 | return ret; |
| 1425 | } |
| 1426 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1427 | static int compare_single(struct super_block *s, void *p) |
| 1428 | { |
| 1429 | return 1; |
| 1430 | } |
| 1431 | |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 1432 | struct dentry *mount_single(struct file_system_type *fs_type, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1433 | int flags, void *data, |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 1434 | int (*fill_super)(struct super_block *, void *, int)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1435 | { |
| 1436 | struct super_block *s; |
| 1437 | int error; |
| 1438 | |
David Howells | 9249e17 | 2012-06-25 12:55:37 +0100 | [diff] [blame] | 1439 | s = sget(fs_type, compare_single, set_anon_super, flags, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1440 | if (IS_ERR(s)) |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 1441 | return ERR_CAST(s); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1442 | if (!s->s_root) { |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1443 | error = fill_super(s, data, flags & SB_SILENT ? 1 : 0); |
David Howells | 8d0347f | 2018-11-04 09:28:36 -0500 | [diff] [blame] | 1444 | if (!error) |
| 1445 | s->s_flags |= SB_ACTIVE; |
Kay Sievers | 9329d1be | 2009-12-18 21:18:15 +0100 | [diff] [blame] | 1446 | } else { |
David Howells | 8d0347f | 2018-11-04 09:28:36 -0500 | [diff] [blame] | 1447 | error = reconfigure_single(s, flags, data); |
| 1448 | } |
| 1449 | if (unlikely(error)) { |
| 1450 | deactivate_locked_super(s); |
| 1451 | return ERR_PTR(error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1452 | } |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 1453 | return dget(s->s_root); |
| 1454 | } |
| 1455 | EXPORT_SYMBOL(mount_single); |
| 1456 | |
David Howells | 9bc61ab | 2018-11-04 03:19:03 -0500 | [diff] [blame] | 1457 | /** |
| 1458 | * vfs_get_tree - Get the mountable root |
| 1459 | * @fc: The superblock configuration context. |
| 1460 | * |
| 1461 | * The filesystem is invoked to get or create a superblock which can then later |
| 1462 | * be used for mounting. The filesystem places a pointer to the root to be |
| 1463 | * used for mounting in @fc->root. |
| 1464 | */ |
| 1465 | int vfs_get_tree(struct fs_context *fc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1466 | { |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 1467 | struct super_block *sb; |
David Howells | 9bc61ab | 2018-11-04 03:19:03 -0500 | [diff] [blame] | 1468 | int error; |
Al Viro | 8089352 | 2010-02-05 09:30:46 -0500 | [diff] [blame] | 1469 | |
David Howells | 06a2ae5 | 2018-11-01 23:07:26 +0000 | [diff] [blame] | 1470 | if (fc->fs_type->fs_flags & FS_REQUIRES_DEV && !fc->source) { |
| 1471 | errorf(fc, "Filesystem requires source device"); |
Al Viro | f3a09c9 | 2018-12-23 18:55:56 -0500 | [diff] [blame] | 1472 | return -ENOENT; |
David Howells | 06a2ae5 | 2018-11-01 23:07:26 +0000 | [diff] [blame] | 1473 | } |
Al Viro | f3a09c9 | 2018-12-23 18:55:56 -0500 | [diff] [blame] | 1474 | |
| 1475 | if (fc->root) |
| 1476 | return -EBUSY; |
| 1477 | |
| 1478 | /* Get the mountable root in fc->root, with a ref on the root and a ref |
| 1479 | * on the superblock. |
| 1480 | */ |
| 1481 | error = fc->ops->get_tree(fc); |
David Howells | 9bc61ab | 2018-11-04 03:19:03 -0500 | [diff] [blame] | 1482 | if (error < 0) |
| 1483 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1484 | |
Al Viro | f3a09c9 | 2018-12-23 18:55:56 -0500 | [diff] [blame] | 1485 | if (!fc->root) { |
| 1486 | pr_err("Filesystem %s get_tree() didn't set fc->root\n", |
| 1487 | fc->fs_type->name); |
| 1488 | /* We don't know what the locking state of the superblock is - |
| 1489 | * if there is a superblock. |
| 1490 | */ |
| 1491 | BUG(); |
| 1492 | } |
| 1493 | |
David Howells | 9bc61ab | 2018-11-04 03:19:03 -0500 | [diff] [blame] | 1494 | sb = fc->root->d_sb; |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 1495 | WARN_ON(!sb->s_bdi); |
Dave Chinner | 79f546a | 2018-05-11 11:20:57 +1000 | [diff] [blame] | 1496 | |
Al Viro | a0c9a8b | 2018-11-04 07:18:51 -0500 | [diff] [blame] | 1497 | if (fc->subtype && !sb->s_subtype) { |
| 1498 | sb->s_subtype = fc->subtype; |
| 1499 | fc->subtype = NULL; |
| 1500 | } |
| 1501 | |
Dave Chinner | 79f546a | 2018-05-11 11:20:57 +1000 | [diff] [blame] | 1502 | /* |
| 1503 | * Write barrier is for super_cache_count(). We place it before setting |
| 1504 | * SB_BORN as the data dependency between the two functions is the |
| 1505 | * superblock structure contents that we just set up, not the SB_BORN |
| 1506 | * flag. |
| 1507 | */ |
| 1508 | smp_wmb(); |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1509 | sb->s_flags |= SB_BORN; |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 1510 | |
David Howells | 9bc61ab | 2018-11-04 03:19:03 -0500 | [diff] [blame] | 1511 | error = security_sb_set_mnt_opts(sb, fc->security, 0, NULL); |
Al Viro | c9ce29e | 2018-12-20 15:04:50 -0500 | [diff] [blame] | 1512 | if (unlikely(error)) { |
| 1513 | fc_drop_locked(fc); |
| 1514 | return error; |
Al Viro | a10d7c2 | 2018-12-05 11:58:35 -0500 | [diff] [blame] | 1515 | } |
| 1516 | |
Jeff Layton | 42cb56a | 2009-09-18 13:05:53 -0700 | [diff] [blame] | 1517 | /* |
| 1518 | * filesystems should never set s_maxbytes larger than MAX_LFS_FILESIZE |
| 1519 | * but s_maxbytes was an unsigned long long for many releases. Throw |
| 1520 | * this warning for a little while to try and catch filesystems that |
Jeff Layton | 4358b56 | 2011-03-29 09:33:31 -0400 | [diff] [blame] | 1521 | * violate this rule. |
Jeff Layton | 42cb56a | 2009-09-18 13:05:53 -0700 | [diff] [blame] | 1522 | */ |
Al Viro | 9d412a4 | 2011-03-17 22:08:28 -0400 | [diff] [blame] | 1523 | WARN((sb->s_maxbytes < 0), "%s set sb->s_maxbytes to " |
David Howells | 9bc61ab | 2018-11-04 03:19:03 -0500 | [diff] [blame] | 1524 | "negative value (%lld)\n", fc->fs_type->name, sb->s_maxbytes); |
Jeff Layton | 42cb56a | 2009-09-18 13:05:53 -0700 | [diff] [blame] | 1525 | |
David Howells | 9bc61ab | 2018-11-04 03:19:03 -0500 | [diff] [blame] | 1526 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1527 | } |
David Howells | 9bc61ab | 2018-11-04 03:19:03 -0500 | [diff] [blame] | 1528 | EXPORT_SYMBOL(vfs_get_tree); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1529 | |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1530 | /* |
Jan Kara | fca3934 | 2017-04-12 12:24:28 +0200 | [diff] [blame] | 1531 | * Setup private BDI for given superblock. It gets automatically cleaned up |
| 1532 | * in generic_shutdown_super(). |
| 1533 | */ |
| 1534 | int super_setup_bdi_name(struct super_block *sb, char *fmt, ...) |
| 1535 | { |
| 1536 | struct backing_dev_info *bdi; |
| 1537 | int err; |
| 1538 | va_list args; |
| 1539 | |
| 1540 | bdi = bdi_alloc(GFP_KERNEL); |
| 1541 | if (!bdi) |
| 1542 | return -ENOMEM; |
| 1543 | |
| 1544 | bdi->name = sb->s_type->name; |
| 1545 | |
| 1546 | va_start(args, fmt); |
Jan Kara | 7c4cc30 | 2017-04-12 12:24:49 +0200 | [diff] [blame] | 1547 | err = bdi_register_va(bdi, fmt, args); |
Jan Kara | fca3934 | 2017-04-12 12:24:28 +0200 | [diff] [blame] | 1548 | va_end(args); |
| 1549 | if (err) { |
| 1550 | bdi_put(bdi); |
| 1551 | return err; |
| 1552 | } |
| 1553 | WARN_ON(sb->s_bdi != &noop_backing_dev_info); |
| 1554 | sb->s_bdi = bdi; |
Jan Kara | fca3934 | 2017-04-12 12:24:28 +0200 | [diff] [blame] | 1555 | |
| 1556 | return 0; |
| 1557 | } |
| 1558 | EXPORT_SYMBOL(super_setup_bdi_name); |
| 1559 | |
| 1560 | /* |
| 1561 | * Setup private BDI for given superblock. I gets automatically cleaned up |
| 1562 | * in generic_shutdown_super(). |
| 1563 | */ |
| 1564 | int super_setup_bdi(struct super_block *sb) |
| 1565 | { |
| 1566 | static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0); |
| 1567 | |
| 1568 | return super_setup_bdi_name(sb, "%.28s-%ld", sb->s_type->name, |
| 1569 | atomic_long_inc_return(&bdi_seq)); |
| 1570 | } |
| 1571 | EXPORT_SYMBOL(super_setup_bdi); |
| 1572 | |
| 1573 | /* |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1574 | * This is an internal function, please use sb_end_{write,pagefault,intwrite} |
| 1575 | * instead. |
| 1576 | */ |
| 1577 | void __sb_end_write(struct super_block *sb, int level) |
| 1578 | { |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1579 | percpu_up_read(sb->s_writers.rw_sem + level-1); |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1580 | } |
| 1581 | EXPORT_SYMBOL(__sb_end_write); |
| 1582 | |
Oleg Nesterov | f4b554a | 2015-07-20 00:50:55 +0200 | [diff] [blame] | 1583 | /* |
| 1584 | * This is an internal function, please use sb_start_{write,pagefault,intwrite} |
| 1585 | * instead. |
| 1586 | */ |
| 1587 | int __sb_start_write(struct super_block *sb, int level, bool wait) |
| 1588 | { |
| 1589 | bool force_trylock = false; |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1590 | int ret = 1; |
Oleg Nesterov | f4b554a | 2015-07-20 00:50:55 +0200 | [diff] [blame] | 1591 | |
| 1592 | #ifdef CONFIG_LOCKDEP |
| 1593 | /* |
| 1594 | * We want lockdep to tell us about possible deadlocks with freezing |
| 1595 | * but it's it bit tricky to properly instrument it. Getting a freeze |
| 1596 | * protection works as getting a read lock but there are subtle |
| 1597 | * problems. XFS for example gets freeze protection on internal level |
| 1598 | * twice in some cases, which is OK only because we already hold a |
| 1599 | * freeze protection also on higher level. Due to these cases we have |
| 1600 | * to use wait == F (trylock mode) which must not fail. |
| 1601 | */ |
| 1602 | if (wait) { |
| 1603 | int i; |
| 1604 | |
| 1605 | for (i = 0; i < level - 1; i++) |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1606 | if (percpu_rwsem_is_held(sb->s_writers.rw_sem + i)) { |
Oleg Nesterov | f4b554a | 2015-07-20 00:50:55 +0200 | [diff] [blame] | 1607 | force_trylock = true; |
| 1608 | break; |
| 1609 | } |
| 1610 | } |
| 1611 | #endif |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1612 | if (wait && !force_trylock) |
| 1613 | percpu_down_read(sb->s_writers.rw_sem + level-1); |
| 1614 | else |
| 1615 | ret = percpu_down_read_trylock(sb->s_writers.rw_sem + level-1); |
| 1616 | |
Vincent Stehlé | 22224a1 | 2015-09-21 17:18:34 +0200 | [diff] [blame] | 1617 | WARN_ON(force_trylock && !ret); |
Oleg Nesterov | f4b554a | 2015-07-20 00:50:55 +0200 | [diff] [blame] | 1618 | return ret; |
| 1619 | } |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1620 | EXPORT_SYMBOL(__sb_start_write); |
| 1621 | |
| 1622 | /** |
| 1623 | * sb_wait_write - wait until all writers to given file system finish |
| 1624 | * @sb: the super for which we wait |
| 1625 | * @level: type of writers we wait for (normal vs page fault) |
| 1626 | * |
| 1627 | * 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] | 1628 | * system. |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1629 | */ |
| 1630 | static void sb_wait_write(struct super_block *sb, int level) |
| 1631 | { |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1632 | percpu_down_write(sb->s_writers.rw_sem + level-1); |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1633 | } |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1634 | |
Oleg Nesterov | f1a9622 | 2016-09-26 18:55:25 +0200 | [diff] [blame] | 1635 | /* |
| 1636 | * We are going to return to userspace and forget about these locks, the |
| 1637 | * ownership goes to the caller of thaw_super() which does unlock(). |
| 1638 | */ |
| 1639 | static void lockdep_sb_freeze_release(struct super_block *sb) |
| 1640 | { |
| 1641 | int level; |
| 1642 | |
| 1643 | for (level = SB_FREEZE_LEVELS - 1; level >= 0; level--) |
| 1644 | percpu_rwsem_release(sb->s_writers.rw_sem + level, 0, _THIS_IP_); |
| 1645 | } |
| 1646 | |
| 1647 | /* |
| 1648 | * Tell lockdep we are holding these locks before we call ->unfreeze_fs(sb). |
| 1649 | */ |
| 1650 | static void lockdep_sb_freeze_acquire(struct super_block *sb) |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1651 | { |
| 1652 | int level; |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1653 | |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1654 | for (level = 0; level < SB_FREEZE_LEVELS; ++level) |
| 1655 | percpu_rwsem_acquire(sb->s_writers.rw_sem + level, 0, _THIS_IP_); |
Oleg Nesterov | f1a9622 | 2016-09-26 18:55:25 +0200 | [diff] [blame] | 1656 | } |
| 1657 | |
| 1658 | static void sb_freeze_unlock(struct super_block *sb) |
| 1659 | { |
| 1660 | int level; |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1661 | |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1662 | for (level = SB_FREEZE_LEVELS - 1; level >= 0; level--) |
| 1663 | percpu_up_write(sb->s_writers.rw_sem + level); |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1664 | } |
| 1665 | |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1666 | /** |
Randy Dunlap | 7000d3c | 2010-05-24 22:22:34 -0700 | [diff] [blame] | 1667 | * freeze_super - lock the filesystem and force it into a consistent state |
| 1668 | * @sb: the super to lock |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1669 | * |
| 1670 | * Syncs the super to make sure the filesystem is consistent and calls the fs's |
| 1671 | * freeze_fs. Subsequent calls to this without first thawing the fs will return |
| 1672 | * -EBUSY. |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1673 | * |
| 1674 | * During this function, sb->s_writers.frozen goes through these values: |
| 1675 | * |
| 1676 | * SB_UNFROZEN: File system is normal, all writes progress as usual. |
| 1677 | * |
| 1678 | * SB_FREEZE_WRITE: The file system is in the process of being frozen. New |
| 1679 | * writes should be blocked, though page faults are still allowed. We wait for |
| 1680 | * all writes to complete and then proceed to the next stage. |
| 1681 | * |
| 1682 | * SB_FREEZE_PAGEFAULT: Freezing continues. Now also page faults are blocked |
| 1683 | * but internal fs threads can still modify the filesystem (although they |
| 1684 | * should not dirty new pages or inodes), writeback can run etc. After waiting |
| 1685 | * for all running page faults we sync the filesystem which will clean all |
| 1686 | * dirty pages and inodes (no new dirty pages or inodes can be created when |
| 1687 | * sync is running). |
| 1688 | * |
| 1689 | * SB_FREEZE_FS: The file system is frozen. Now all internal sources of fs |
| 1690 | * modification are blocked (e.g. XFS preallocation truncation on inode |
| 1691 | * reclaim). This is usually implemented by blocking new transactions for |
| 1692 | * filesystems that have them and need this additional guard. After all |
| 1693 | * internal writers are finished we call ->freeze_fs() to finish filesystem |
| 1694 | * freezing. Then we transition to SB_FREEZE_COMPLETE state. This state is |
| 1695 | * mostly auxiliary for filesystems to verify they do not modify frozen fs. |
| 1696 | * |
| 1697 | * sb->s_writers.frozen is protected by sb->s_umount. |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1698 | */ |
| 1699 | int freeze_super(struct super_block *sb) |
| 1700 | { |
| 1701 | int ret; |
| 1702 | |
| 1703 | atomic_inc(&sb->s_active); |
| 1704 | down_write(&sb->s_umount); |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1705 | if (sb->s_writers.frozen != SB_UNFROZEN) { |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1706 | deactivate_locked_super(sb); |
| 1707 | return -EBUSY; |
| 1708 | } |
| 1709 | |
David Howells | e462ec5 | 2017-07-17 08:45:35 +0100 | [diff] [blame] | 1710 | if (!(sb->s_flags & SB_BORN)) { |
Al Viro | dabe0dc | 2012-01-03 21:01:29 -0500 | [diff] [blame] | 1711 | up_write(&sb->s_umount); |
| 1712 | return 0; /* sic - it's "nothing to do" */ |
| 1713 | } |
| 1714 | |
David Howells | bc98a42 | 2017-07-17 08:45:34 +0100 | [diff] [blame] | 1715 | if (sb_rdonly(sb)) { |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1716 | /* Nothing to do really... */ |
| 1717 | sb->s_writers.frozen = SB_FREEZE_COMPLETE; |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1718 | up_write(&sb->s_umount); |
| 1719 | return 0; |
| 1720 | } |
| 1721 | |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1722 | sb->s_writers.frozen = SB_FREEZE_WRITE; |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1723 | /* Release s_umount to preserve sb_start_write -> s_umount ordering */ |
| 1724 | up_write(&sb->s_umount); |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1725 | sb_wait_write(sb, SB_FREEZE_WRITE); |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1726 | down_write(&sb->s_umount); |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1727 | |
| 1728 | /* Now we go and block page faults... */ |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1729 | sb->s_writers.frozen = SB_FREEZE_PAGEFAULT; |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1730 | sb_wait_write(sb, SB_FREEZE_PAGEFAULT); |
| 1731 | |
| 1732 | /* 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] | 1733 | sync_filesystem(sb); |
| 1734 | |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1735 | /* Now wait for internal filesystem counter */ |
| 1736 | sb->s_writers.frozen = SB_FREEZE_FS; |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1737 | sb_wait_write(sb, SB_FREEZE_FS); |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1738 | |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1739 | if (sb->s_op->freeze_fs) { |
| 1740 | ret = sb->s_op->freeze_fs(sb); |
| 1741 | if (ret) { |
| 1742 | printk(KERN_ERR |
| 1743 | "VFS:Filesystem freeze failed\n"); |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1744 | sb->s_writers.frozen = SB_UNFROZEN; |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1745 | sb_freeze_unlock(sb); |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1746 | wake_up(&sb->s_writers.wait_unfrozen); |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1747 | deactivate_locked_super(sb); |
| 1748 | return ret; |
| 1749 | } |
| 1750 | } |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1751 | /* |
Oleg Nesterov | 89f39af | 2016-09-26 18:07:48 +0200 | [diff] [blame] | 1752 | * For debugging purposes so that fs can warn if it sees write activity |
| 1753 | * when frozen is set to SB_FREEZE_COMPLETE, and for thaw_super(). |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1754 | */ |
| 1755 | sb->s_writers.frozen = SB_FREEZE_COMPLETE; |
Oleg Nesterov | f1a9622 | 2016-09-26 18:55:25 +0200 | [diff] [blame] | 1756 | lockdep_sb_freeze_release(sb); |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1757 | up_write(&sb->s_umount); |
| 1758 | return 0; |
| 1759 | } |
| 1760 | EXPORT_SYMBOL(freeze_super); |
| 1761 | |
| 1762 | /** |
| 1763 | * thaw_super -- unlock filesystem |
| 1764 | * @sb: the super to thaw |
| 1765 | * |
| 1766 | * Unlocks the filesystem and marks it writeable again after freeze_super(). |
| 1767 | */ |
Mateusz Guzik | 08fdc8a | 2017-10-03 18:17:41 +0200 | [diff] [blame] | 1768 | static int thaw_super_locked(struct super_block *sb) |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1769 | { |
| 1770 | int error; |
| 1771 | |
Oleg Nesterov | 89f39af | 2016-09-26 18:07:48 +0200 | [diff] [blame] | 1772 | if (sb->s_writers.frozen != SB_FREEZE_COMPLETE) { |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1773 | up_write(&sb->s_umount); |
| 1774 | return -EINVAL; |
| 1775 | } |
| 1776 | |
David Howells | bc98a42 | 2017-07-17 08:45:34 +0100 | [diff] [blame] | 1777 | if (sb_rdonly(sb)) { |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1778 | sb->s_writers.frozen = SB_UNFROZEN; |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1779 | goto out; |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1780 | } |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1781 | |
Oleg Nesterov | f1a9622 | 2016-09-26 18:55:25 +0200 | [diff] [blame] | 1782 | lockdep_sb_freeze_acquire(sb); |
| 1783 | |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1784 | if (sb->s_op->unfreeze_fs) { |
| 1785 | error = sb->s_op->unfreeze_fs(sb); |
| 1786 | if (error) { |
| 1787 | printk(KERN_ERR |
| 1788 | "VFS:Filesystem thaw failed\n"); |
Oleg Nesterov | f1a9622 | 2016-09-26 18:55:25 +0200 | [diff] [blame] | 1789 | lockdep_sb_freeze_release(sb); |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1790 | up_write(&sb->s_umount); |
| 1791 | return error; |
| 1792 | } |
| 1793 | } |
| 1794 | |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1795 | sb->s_writers.frozen = SB_UNFROZEN; |
Oleg Nesterov | 8129ed2 | 2015-08-11 17:05:04 +0200 | [diff] [blame] | 1796 | sb_freeze_unlock(sb); |
| 1797 | out: |
Jan Kara | 5accdf8 | 2012-06-12 16:20:34 +0200 | [diff] [blame] | 1798 | wake_up(&sb->s_writers.wait_unfrozen); |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1799 | deactivate_locked_super(sb); |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1800 | return 0; |
| 1801 | } |
Mateusz Guzik | 08fdc8a | 2017-10-03 18:17:41 +0200 | [diff] [blame] | 1802 | |
| 1803 | int thaw_super(struct super_block *sb) |
| 1804 | { |
| 1805 | down_write(&sb->s_umount); |
| 1806 | return thaw_super_locked(sb); |
| 1807 | } |
Josef Bacik | 18e9e51 | 2010-03-23 10:34:56 -0400 | [diff] [blame] | 1808 | EXPORT_SYMBOL(thaw_super); |