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

[Kamal Mostafa]

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-3.13.y-queue branch of the 3.13.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-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.6.

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

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 2d169581f63c5765a08041ca8b239a4272fe9383 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>
Signed-off-by: Kamal Mostafa <kamal 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 ba60cfd..989dabd 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -188,7 +188,8 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
 	inode = ACCESS_ONCE(entry->d_inode);
 	if (inode && is_bad_inode(inode))
 		goto invalid;
-	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