[PULL 25/34] file-posix: check the use_lock before setting the file lock

[Kevin Wolf]

From: Li Feng <fengli@smartx.com>

The scenario is that when accessing a volume on an NFS filesystem
without supporting the file lock,  Qemu will complain "Failed to lock
byte 100", even when setting the file.locking = off.

We should do file lock related operations only when the file.locking is
enabled, otherwise, the syscall of 'fcntl' will return non-zero.

Signed-off-by: Li Feng <fengli@smartx.com>
Message-Id: <1607341446-85506-1-git-send-email-fengli@smartx.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/file-posix.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/file-posix.c b/block/file-posix.c
index d5fd1dbcd2..806764f7e3 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -3104,7 +3104,7 @@ static int raw_check_perm(BlockDriverState *bs, uint64_t 
perm, uint64_t shared,
     }
 
     /* Copy locks to the new fd */
-    if (s->perm_change_fd) {
+    if (s->perm_change_fd && s->use_lock) {
         ret = raw_apply_lock_bytes(NULL, s->perm_change_fd, perm, ~shared,
                                    false, errp);
         if (ret < 0) {
-- 
2.29.2