lockd: fix regression in lockd's handling of blocked locks
If a client requests a blocking lock, is denied, then requests it again,
then here in nlmsvc_lock() we will call vfs_lock_file() without FL_SLEEP
set, because we've already queued a block and don't need the locks code
to do it again.
But that means vfs_lock_file() will return -EAGAIN instead of
FILE_LOCK_DENIED. So we still need to translate that -EAGAIN return
into a nlm_lck_blocked error in this case, and put ourselves back on
lockd's block list.
The bug was introduced by bde74e4bc64415b1 "locks: add special return
value for asynchronous locks".
Thanks to Frank van Maarseveen for the report; his original test
case was essentially
for i in `seq 30`; do flock /nfsmount/foo sleep 10 & done
Tested-by: Frank van Maarseveen <frankvm@frankvm.com>
Reported-by: Frank van Maarseveen <frankvm@frankvm.com>
Cc: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index 6063a8e..763b78a 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -427,7 +427,7 @@
goto out;
case -EAGAIN:
ret = nlm_lck_denied;
- goto out;
+ break;
case FILE_LOCK_DEFERRED:
if (wait)
break;
@@ -443,6 +443,10 @@
goto out;
}
+ ret = nlm_lck_denied;
+ if (!wait)
+ goto out;
+
ret = nlm_lck_blocked;
/* Append to list of blocked */