Patch "CIFS: Fix a deadlock when a file is reopened" has been added to the 3.10-stable tree

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This is a note to let you know that I've just added the patch titled

    CIFS: Fix a deadlock when a file is reopened

to the 3.10-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:
     cifs-fix-a-deadlock-when-a-file-is-reopened.patch
and it can be found in the queue-3.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From 689c3db4d57a73bee6c5ad7797fce7b54d32a87c Mon Sep 17 00:00:00 2001
From: Pavel Shilovsky <pshilovsky@xxxxxxxxx>
Date: Thu, 11 Jul 2013 11:17:45 +0400
Subject: CIFS: Fix a deadlock when a file is reopened

From: Pavel Shilovsky <pshilovsky@xxxxxxxxx>

commit 689c3db4d57a73bee6c5ad7797fce7b54d32a87c upstream.

If we request reading or writing on a file that needs to be
reopened, it causes the deadlock: we are already holding rw
semaphore for reading and then we try to acquire it for writing
in cifs_relock_file. Fix this by acquiring the semaphore for
reading in cifs_relock_file due to we don't make any changes in
locks and don't need a write access.

Signed-off-by: Pavel Shilovsky <pshilovsky@xxxxxxxxx>
Acked-by: Jeff Layton <jlayton@xxxxxxxxxx>
Signed-off-by: Steve French <smfrench@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/cifs/file.c |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -553,11 +553,10 @@ cifs_relock_file(struct cifsFileInfo *cf
 	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
 	int rc = 0;
 
-	/* we are going to update can_cache_brlcks here - need a write access */
-	down_write(&cinode->lock_sem);
+	down_read(&cinode->lock_sem);
 	if (cinode->can_cache_brlcks) {
-		/* can cache locks - no need to push them */
-		up_write(&cinode->lock_sem);
+		/* can cache locks - no need to relock */
+		up_read(&cinode->lock_sem);
 		return rc;
 	}
 
@@ -568,7 +567,7 @@ cifs_relock_file(struct cifsFileInfo *cf
 	else
 		rc = tcon->ses->server->ops->push_mand_locks(cfile);
 
-	up_write(&cinode->lock_sem);
+	up_read(&cinode->lock_sem);
 	return rc;
 }
 


Patches currently in stable-queue which might be from pshilovsky@xxxxxxxxx are

queue-3.10/cifs-fix-a-deadlock-when-a-file-is-reopened.patch
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