From 0444d76ae64fffc7851797fc1b6ebdbb44ac504a Mon Sep 17 00:00:00 2001
From: Dave Chinner <dchinner@redhat.com>
Date: Tue, 29 Mar 2011 18:08:50 +1100
Subject: [PATCH] fs: don't use igrab() while holding i_lock
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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>
---
fs/ceph/addr.c | 2 +-
fs/ceph/snap.c | 4 ++--
fs/nfs/nfs4state.c | 3 ++-
3 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 561438b6a50cd..37368ba2e67c1 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -92,7 +92,7 @@ static int ceph_set_page_dirty(struct page *page)
ci->i_head_snapc = ceph_get_snap_context(snapc);
++ci->i_wrbuffer_ref_head;
if (ci->i_wrbuffer_ref == 0)
- igrab(inode);
+ ihold(inode);
++ci->i_wrbuffer_ref;
dout("%p set_page_dirty %p idx %lu head %d/%d -> %d/%d "
"snapc %p seq %lld (%d snaps)\n",
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index f40b9139e4373..0aee66b92af31 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -463,8 +463,8 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci)
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);
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index ab1bf5bb021f5..a6804f704d9d8 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -590,7 +590,8 @@ nfs4_get_open_state(struct inode *inode, struct nfs4_state_owner *owner)
state->owner = owner;
atomic_inc(&owner->so_count);
list_add(&state->inode_states, &nfsi->open_states);
- state->inode = igrab(inode);
+ ihold(inode);
+ state->inode = inode;
spin_unlock(&inode->i_lock);
/* Note: The reclaim code dictates that we add stateless
* and read-only stateids to the end of the list */
--
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