nfs: opendir/closedir for every readdir

Revert "nfs3: Unref & unbind dir fd with inode lock on EOF"

This reverts commit 4e6fb304ce41acbaf7c9ba67c06bf443e65082e8.

The above commit (which unbinds fds at EOF) does not fix the original
bug (1619) because a readdir from a second app could have already
started before the readdir_cbk of the first app's readdir reaches
NFS code. Hence the race still exists.

Performing extra unrefs when EOF is received is not a reliable way
of detecting that a client has performed a closedir (and to close
the fd ourselves). Neither is interpreting a 0 cookies a new opendir.
Clients can always use telldir/seekdir and hit EOFs twice.

Due to the way NFS3 protocol is designed, it is just not possible
for the server to reliably detect opendirs/closedirs performed by
the client and map the corresponding readdirs to the same dir fd
on the server side.

The only reliable way of fixing this is to perform opendir/closedir
at the cost of performance. Any optimization towards keeping dir fds
open attempting to map them with application's opendir/closedir will
either result in fd leaks or extra fd unrefs.

Signed-off-by: Anand V. Avati <avati@blackhole.gluster.com>
Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 2061 (NFS server crashes in readdir_fstat_cbk due to extra fd unref)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=2061

1 files changed, 0 insertions, 23 deletions

diff --git a/libglusterfs/src/fd.c b/libglusterfs/src/fd.c
index e4e75d8040f..def15255728 100644
--- a/libglusterfs/src/fd.c
+++ b/libglusterfs/src/fd.c
@@ -500,29 +500,6 @@ fd_bind (fd_t *fd)
 }
 
 
-void
-fd_unref_unbind (fd_t *fd)
-{
-        GF_ASSERT (fd->refcount);
-
-        LOCK (&fd->inode->lock);
-        {
-	        --fd->refcount;
-                /* Better know what you're doing with this function
-                 * because it does not do what fd_destroy does when
-                 * refcount goes to 0.
-                 * Make sure you only call this when you know there are
-                 * pending refs on the fd.
-                 */
-                GF_ASSERT (fd->refcount);
-		list_del_init (&fd->inode_list);
-        }
-        UNLOCK (&fd->inode->lock);
-
-        return;
-}
-
-
 fd_t *
 fd_create (inode_t *inode, pid_t pid)
 {