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| author | Al Viro <viro@zeniv.linux.org.uk> | 2011-11-17 21:05:22 +0100 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2012-01-09 01:33:24 +0100 |
| commit | 10f6327b5d26660e06120ba17cff993cb616b1d2 (patch) | |
| tree | ee1bade28f62a896db62570589abcb9c8f6f2936 /fs | |
| parent | btrfs: fix mount/umount race (diff) | |
| download | linux-10f6327b5d26660e06120ba17cff993cb616b1d2.tar.xz linux-10f6327b5d26660e06120ba17cff993cb616b1d2.zip | |
btrfs: fix a deadlock in btrfs_scan_one_device()
pathname resolution under a global mutex, taken on some paths in ->mount()
is a Bad Idea(tm) - think what happens if said pathname resolution triggers
automount of some btrfs instance and walks into attempt to grab the same
mutex. Deadlock - we are waiting for daemon to finish walking the path,
daemon is waiting for us to release the mutex...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/volumes.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index f4b839fd3c9d..96bb3c0a79b0 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -706,8 +706,6 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder, u64 devid; u64 transid; - mutex_lock(&uuid_mutex); - flags |= FMODE_EXCL; bdev = blkdev_get_by_path(path, flags, holder); @@ -716,6 +714,7 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder, goto error; } + mutex_lock(&uuid_mutex); ret = set_blocksize(bdev, 4096); if (ret) goto error_close; @@ -737,9 +736,9 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder, brelse(bh); error_close: + mutex_unlock(&uuid_mutex); blkdev_put(bdev, flags); error: - mutex_unlock(&uuid_mutex); return ret; } |