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| author | Ian Kent <raven@themaw.net> | 2010-11-22 02:21:38 +0000 |
|---|---|---|
| committer | Chris Mason <chris.mason@oracle.com> | 2010-11-27 13:37:44 -0500 |
| commit | 619c8c763928841b1112e1d417f88bc1d44daecb (patch) | |
| tree | 23fc73cf043faac2cdb15a0b22e6e9e29a69797a /fs | |
| parent | bc1cbf1f86aa2501efa9ca637c736fce6bcc4b1d (diff) | |
| download | linux-stable-619c8c763928841b1112e1d417f88bc1d44daecb.tar.gz linux-stable-619c8c763928841b1112e1d417f88bc1d44daecb.tar.bz2 linux-stable-619c8c763928841b1112e1d417f88bc1d44daecb.zip | |
Btrfs - fix race between btrfs_get_sb() and umount
When mounting a btrfs file system btrfs_test_super() may attempt to
use sb->s_fs_info, the btrfs root, of a super block that is going away
and that has had the btrfs root set to NULL in its ->put_super(). But
if the super block is going away it cannot be an existing super block
so we can return false in this case.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/super.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 66e4612a7916..141fb317d3bc 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -566,6 +566,12 @@ static int btrfs_test_super(struct super_block *s, void *data) struct btrfs_fs_devices *test_fs_devices = data; struct btrfs_root *root = btrfs_sb(s); + /* + * If this super block is going away, return false as it + * can't match as an existing super block. + */ + if (!atomic_read(&s->s_active)) + return 0; return root->fs_info->fs_devices == test_fs_devices; } |