[Gluster-devel] [PATCH] fuse: ignore entry-timeout on LOOKUP_REVAL

[Anand Avati]

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>
---
 fs/fuse/dir.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 4219835..4eaa30d 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -198,7 +198,7 @@ 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 (fuse_dentry_time(entry) < get_jiffies_64()) {
+	else if (fuse_dentry_time(entry) < get_jiffies_64() || (flags & LOOKUP_REVAL)) {
 		int err;
 		struct fuse_entry_out outarg;
 		struct fuse_req *req;
-- 
1.7.1