This is a note to let you know that I've just added the patch titled
vfs: dcache: use DCACHE_DENTRY_KILLED instead of DCACHE_DISCONNECTED in
d_kill()
to the 3.5-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-dcache-use-dcache_dentry_killed-instead-of-dcache_disconnected-in-d_kill.patch
and it can be found in the queue-3.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From b161dfa6937ae46d50adce8a7c6b12233e96e7bd Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <[email protected]>
Date: Mon, 17 Sep 2012 22:31:38 +0200
Subject: vfs: dcache: use DCACHE_DENTRY_KILLED instead of DCACHE_DISCONNECTED
in d_kill()
From: Miklos Szeredi <[email protected]>
commit b161dfa6937ae46d50adce8a7c6b12233e96e7bd upstream.
IBM reported a soft lockup after applying the fix for the rename_lock
deadlock. Commit c83ce989cb5f ("VFS: Fix the nfs sillyrename regression
in kernel 2.6.38") was found to be the culprit.
The nfs sillyrename fix used DCACHE_DISCONNECTED to indicate that the
dentry was killed. This flag can be set on non-killed dentries too,
which results in infinite retries when trying to traverse the dentry
tree.
This patch introduces a separate flag: DCACHE_DENTRY_KILLED, which is
only set in d_kill() and makes try_to_ascend() test only this flag.
IBM reported successful test results with this patch.
Signed-off-by: Miklos Szeredi <[email protected]>
Cc: Trond Myklebust <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/dcache.c | 4 ++--
include/linux/dcache.h | 2 ++
2 files changed, 4 insertions(+), 2 deletions(-)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -389,7 +389,7 @@ static struct dentry *d_kill(struct dent
* Inform try_to_ascend() that we are no longer attached to the
* dentry tree
*/
- dentry->d_flags |= DCACHE_DISCONNECTED;
+ dentry->d_flags |= DCACHE_DENTRY_KILLED;
if (parent)
spin_unlock(&parent->d_lock);
dentry_iput(dentry);
@@ -1046,7 +1046,7 @@ static struct dentry *try_to_ascend(stru
* or deletion
*/
if (new != old->d_parent ||
- (old->d_flags & DCACHE_DISCONNECTED) ||
+ (old->d_flags & DCACHE_DENTRY_KILLED) ||
(!locked && read_seqretry(&rename_lock, seq))) {
spin_unlock(&new->d_lock);
new = NULL;
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -206,6 +206,8 @@ struct dentry_operations {
#define DCACHE_MANAGED_DENTRY \
(DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT)
+#define DCACHE_DENTRY_KILLED 0x100000
+
extern seqlock_t rename_lock;
static inline int dname_external(struct dentry *dentry)
Patches currently in stable-queue which might be from [email protected] are
queue-3.5/vfs-dcache-use-dcache_dentry_killed-instead-of-dcache_disconnected-in-d_kill.patch
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