Filipe David Borba Manana
2014-Jan-11 21:31 UTC
[PATCH] Btrfs: unlock inodes in correct order in clone ioctl
In the clone ioctl, when the source and target inodes are different,
we can acquire their mutexes in 2 possible different orders. After
we're done cloning, we were releasing the mutexes always in the same
order - the most correct way of doing it is to release them by the
reverse order they were acquired.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
---
fs/btrfs/ioctl.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index cced205..98cb3e8 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3266,9 +3266,17 @@ static noinline long btrfs_ioctl_clone(struct file *file,
unsigned long srcfd,
unlock_extent(&BTRFS_I(src)->io_tree, off, off + len - 1);
out_unlock:
- mutex_unlock(&src->i_mutex);
- if (!same_inode)
- mutex_unlock(&inode->i_mutex);
+ if (!same_inode) {
+ if (inode < src) {
+ mutex_unlock(&src->i_mutex);
+ mutex_unlock(&inode->i_mutex);
+ } else {
+ mutex_unlock(&inode->i_mutex);
+ mutex_unlock(&src->i_mutex);
+ }
+ } else {
+ mutex_unlock(&src->i_mutex);
+ }
out_fput:
fdput(src_file);
out_drop_write:
--
1.7.9.5
--
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