From: Li Feng <fengli@smartx.com>
Date: Mon, 7 Dec 2020 11:44:06 +0000 (+0800)
Subject: file-posix: check the use_lock before setting the file lock
X-Git-Tag: qemu-xen-4.16.0-rc4~435^2~9
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=eb43ea16dcb7e6ab01db321b5edac3e593556e7d;p=qemu-xen.git

file-posix: check the use_lock before setting the file lock

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>
---

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) {