diff options
Diffstat (limited to 'fs/super.c')
| -rw-r--r-- | fs/super.c | 33 |
1 files changed, 31 insertions, 2 deletions
diff --git a/fs/super.c b/fs/super.c index 4fca6657f442..734ed584a946 100644 --- a/fs/super.c +++ b/fs/super.c @@ -423,6 +423,35 @@ bool trylock_super(struct super_block *sb) } /** + * retire_super - prevents superblock from being reused + * @sb: superblock to retire + * + * The function marks superblock to be ignored in superblock test, which + * prevents it from being reused for any new mounts. If the superblock has + * a private bdi, it also unregisters it, but doesn't reduce the refcount + * of the superblock to prevent potential races. The refcount is reduced + * by generic_shutdown_super(). The function can not be called + * concurrently with generic_shutdown_super(). It is safe to call the + * function multiple times, subsequent calls have no effect. + * + * The marker will affect the re-use only for block-device-based + * superblocks. Other superblocks will still get marked if this function + * is used, but that will not affect their reusability. + */ +void retire_super(struct super_block *sb) +{ + WARN_ON(!sb->s_bdev); + down_write(&sb->s_umount); + if (sb->s_iflags & SB_I_PERSB_BDI) { + bdi_unregister(sb->s_bdi); + sb->s_iflags &= ~SB_I_PERSB_BDI; + } + sb->s_iflags |= SB_I_RETIRED; + up_write(&sb->s_umount); +} +EXPORT_SYMBOL(retire_super); + +/** * generic_shutdown_super - common helper for ->kill_sb() * @sb: superblock to kill * @@ -1216,7 +1245,7 @@ static int set_bdev_super_fc(struct super_block *s, struct fs_context *fc) static int test_bdev_super_fc(struct super_block *s, struct fs_context *fc) { - return s->s_bdev == fc->sget_key; + return !(s->s_iflags & SB_I_RETIRED) && s->s_bdev == fc->sget_key; } /** @@ -1309,7 +1338,7 @@ EXPORT_SYMBOL(get_tree_bdev); static int test_bdev_super(struct super_block *s, void *data) { - return (void *)s->s_bdev == data; + return !(s->s_iflags & SB_I_RETIRED) && (void *)s->s_bdev == data; } struct dentry *mount_bdev(struct file_system_type *fs_type, |