reiserfs: fix xattr root locking/refcount bug

The listxattr() and getxattr() operations are only protected by a read
lock.  As a result, if either of these operations run in parallel, a race
condition exists where the xattr_root will end up being cached twice, which
results in the leaking of a reference and a BUG() on umount.

This patch refactors get_xa_root(), __get_xa_root(), and create_xa_root(),
into one get_xa_root() function that takes the appropriate locking around
the entire critical section.

Reported, diagnosed and tested by Andrea Righi <[email protected]>

Signed-off-by: Jeff Mahoney <[email protected]>
Cc: Andrea Righi <[email protected]>
Cc: "Vladimir V. Saveliev" <[email protected]>
Cc: Edward Shishkin <[email protected]>
Cc: Alex Zarochentsev <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions