fs: don't use igrab() while holding i_lock
Fix the incorrect use of igrab() inside the i_lock in NFS and Ceph‥
If we are already holding the i_lock, we have a reference to the
inode so we can safely use ihold() to gain an extra reference. This
avoids hangs due to lock recursion on the i_lock now that the
inode_lock is gone and igrab() uses the i_lock itself.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: Ryan Mallon <ryan@bluewatersys.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index f40b913..0aee66b 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -463,8 +463,8 @@
dout("queue_cap_snap %p cap_snap %p queuing under %p\n", inode,
capsnap, snapc);
- igrab(inode);
-
+ ihold(inode);
+
atomic_set(&capsnap->nref, 1);
capsnap->ci = ci;
INIT_LIST_HEAD(&capsnap->ci_item);