lockd: dont return EAGAIN for a permanent error

Fix nlm_fopen() to return NLM_FAILED (or NLM_LCK_DENIED_NOLOCKS) instead
of NLM_LCK_DENIED.  The latter means the lock request failed because of a
conflicting lock (i.e.  a temporary error), which is wrong in this case.

Also fix the client to return ENOLCK instead of EAGAIN if a blocking lock
request returns with NLM_LOCK_DENIED.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: David Teigland <teigland@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 9 insertions, 1 deletions

diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
index 1f6dc518505c..31668b690e03 100644
--- a/fs/lockd/clntproc.c
+++ b/fs/lockd/clntproc.c
@@ -582,7 +582,15 @@ again:
         }
         if (status < 0)
                 goto out_unlock;
-        status = nlm_stat_to_errno(resp->status);
+        /*
+         * EAGAIN doesn't make sense for sleeping locks, and in some
+         * cases NLM_LCK_DENIED is returned for a permanent error.  So
+         * turn it into an ENOLCK.
+         */
+        if (resp->status == nlm_lck_denied && (fl_flags & FL_SLEEP))
+                status = -ENOLCK;
+        else
+                status = nlm_stat_to_errno(resp->status);
 out_unblock:
         nlmclnt_finish_block(block);
 out: