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| author | Jan Kara <jack@suse.cz> | 2012-02-10 14:03:00 +0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2012-02-14 05:45:38 +0400 |
| commit | 6b6dc836a195e077e76977b6c020a73de411b46d (patch) | |
| tree | 59920a3aab6db4997f6b7a95c753219bdc12bd64 /fs | |
| parent | 074b85175a43a23fdbde60f55feea636e0bf0f85 (diff) | |
| download | linux-6b6dc836a195e077e76977b6c020a73de411b46d.tar.xz | |
vfs: Provide function to get superblock and wait for it to thaw
In quota code we need to find a superblock corresponding to a device and wait
for superblock to be unfrozen. However this waiting has to happen without
s_umount semaphore because that is required for superblock to thaw. So provide
a function in VFS for this to keep dances with s_umount where they belong.
[AV: implementation switched to saner variant]
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/super.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/fs/super.c b/fs/super.c index 6015c02296b7..6277ec6cb60a 100644 --- a/fs/super.c +++ b/fs/super.c @@ -634,6 +634,28 @@ rescan: EXPORT_SYMBOL(get_super); /** + * get_super_thawed - get thawed superblock of a device + * @bdev: device to get the superblock for + * + * Scans the superblock list and finds the superblock of the file system + * mounted on the device. The superblock is returned once it is thawed + * (or immediately if it was not frozen). %NULL is returned if no match + * is found. + */ +struct super_block *get_super_thawed(struct block_device *bdev) +{ + while (1) { + struct super_block *s = get_super(bdev); + if (!s || s->s_frozen == SB_UNFROZEN) + return s; + up_read(&s->s_umount); + vfs_check_frozen(s, SB_FREEZE_WRITE); + put_super(s); + } +} +EXPORT_SYMBOL(get_super_thawed); + +/** * get_active_super - get an active reference to the superblock of a device * @bdev: device to get the superblock for * |