nfsd: grant read delegations to clients holding writes
It's OK to grant a read delegation to a client that holds a write,
as long as it's the only client holding the write.
We originally tried to do this in commit 94415b06eb8a ("nfsd4: a
client's own opens needn't prevent delegations"), which had to be
reverted in commit 6ee65a773096 ("Revert "nfsd4: a client's own
opens needn't prevent delegations"").
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
diff --git a/fs/locks.c b/fs/locks.c
index 6125d2d..bcc71c4 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1808,6 +1808,9 @@ check_conflicting_open(struct file *filp, const long arg, int flags)
if (flags & FL_LAYOUT)
return 0;
+ if (flags & FL_DELEG)
+ /* We leave these checks to the caller */
+ return 0;
if (arg == F_RDLCK)
return inode_is_open_for_write(inode) ? -EAGAIN : 0;