This is a note to let you know that I've just added the patch titled
VFS: Fix the nfs sillyrename regression in kernel 2.6.38
to the 2.6.38-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
vfs-fix-the-nfs-sillyrename-regression-in-kernel-2.6.38.patch
and it can be found in the queue-2.6.38 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From c83ce989cb5ff86575821992ea82c4df5c388ebc Mon Sep 17 00:00:00 2001
From: Trond Myklebust <[email protected]>
Date: Tue, 15 Mar 2011 13:36:43 -0400
Subject: VFS: Fix the nfs sillyrename regression in kernel 2.6.38
From: Trond Myklebust <[email protected]>
commit c83ce989cb5ff86575821992ea82c4df5c388ebc upstream.
The new vfs locking scheme introduced in 2.6.38 breaks NFS sillyrename
because the latter relies on being able to determine the parent
directory of the dentry in the ->iput() callback in order to send the
appropriate unlink rpc call.
Looking at the code that cares about races with dput(), there doesn't
seem to be anything that specifically uses d_parent as a test for
whether or not there is a race:
- __d_lookup_rcu(), __d_lookup() all test for d_hashed() after d_parent
- shrink_dcache_for_umount() is safe since nothing else can rearrange
the dentries in that super block.
- have_submount(), select_parent() and d_genocide() can test for a
deletion if we set the DCACHE_DISCONNECTED flag when the dentry
is removed from the parent's d_subdirs list.
Signed-off-by: Trond Myklebust <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/dcache.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -296,8 +296,12 @@ static struct dentry *d_kill(struct dent
__releases(parent->d_lock)
__releases(dentry->d_inode->i_lock)
{
- dentry->d_parent = NULL;
list_del(&dentry->d_u.d_child);
+ /*
+ * Inform try_to_ascend() that we are no longer attached to the
+ * dentry tree
+ */
+ dentry->d_flags |= DCACHE_DISCONNECTED;
if (parent)
spin_unlock(&parent->d_lock);
dentry_iput(dentry);
@@ -1030,6 +1034,7 @@ static struct dentry *try_to_ascend(stru
* or deletion
*/
if (new != old->d_parent ||
+ (old->d_flags & DCACHE_DISCONNECTED) ||
(!locked && read_seqretry(&rename_lock, seq))) {
spin_unlock(&new->d_lock);
new = NULL;
Patches currently in stable-queue which might be from
[email protected] are
queue-2.6.38/vfs-fix-the-nfs-sillyrename-regression-in-kernel-2.6.38.patch
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