[3.11.y.z extended stable] Patch "fuse: ignore entry-timeout on LOOKUP_REVAL" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    fuse: ignore entry-timeout on LOOKUP_REVAL

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 40d86ea4517a54ae4697bcca4e22615ff87271dc Mon Sep 17 00:00:00 2001
From: Anand Avati <avati at redhat.com>
Date: Thu, 26 Jun 2014 20:21:57 -0400
Subject: fuse: ignore entry-timeout on LOOKUP_REVAL

commit 154210ccb3a871e631bf39fdeb7a8731d98af87b upstream.

The following test case demonstrates the bug:

  sh# mount -t glusterfs localhost:meta-test /mnt/one

  sh# mount -t glusterfs localhost:meta-test /mnt/two

  sh# echo stuff > /mnt/one/file; rm -f /mnt/two/file; echo stuff > /mnt/one/file
  bash: /mnt/one/file: Stale file handle

  sh# echo stuff > /mnt/one/file; rm -f /mnt/two/file; sleep 1; echo stuff > /mnt/one/file

On the second open() on /mnt/one, FUSE would have used the old
nodeid (file handle) trying to re-open it. Gluster is returning
-ESTALE. The ESTALE propagates back to namei.c:filename_lookup()
where lookup is re-attempted with LOOKUP_REVAL. The right
behavior now, would be for FUSE to ignore the entry-timeout and
and do the up-call revalidation. Instead FUSE is ignoring
LOOKUP_REVAL, succeeding the revalidation (because entry-timeout
has not passed), and open() is again retried on the old file
handle and finally the ESTALE is going back to the application.

Fix: if revalidation is happening with LOOKUP_REVAL, then ignore
entry-timeout and always do the up-call.

Signed-off-by: Anand Avati <avati at redhat.com>
Reviewed-by: Niels de Vos <ndevos at redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi at suse.cz>
[ luis: backported to 3.11: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/fuse/dir.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index ac00468b93d5..495d446b1911 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -186,7 +186,8 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
 	inode = ACCESS_ONCE(entry->d_inode);
 	if (inode && is_bad_inode(inode))
 		return 0;
-	else if (time_before64(fuse_dentry_time(entry), get_jiffies_64())) {
+	else if (time_before64(fuse_dentry_time(entry), get_jiffies_64()) ||
+		 (flags & LOOKUP_REVAL)) {
 		int err;
 		struct fuse_entry_out outarg;
 		struct fuse_req *req;
--
1.9.1