diff mbox series

[PULL,5/9] block/file-posix: do not fail on unlock bytes

Message ID 20190402124907.24421-6-kwolf@redhat.com (mailing list archive)
State New, archived
Headers show
Series [PULL,1/9] iotests: Fix test 200 on s390x without virtio-pci | expand

Commit Message

Kevin Wolf April 2, 2019, 12:49 p.m. UTC 
From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

bdrv_replace_child() calls bdrv_check_perm() with error_abort on
loosening permissions. However file-locking operations may fail even
in this case, for example on NFS. And this leads to Qemu crash.

Let's avoid such errors. Note, that we ignore such things anyway on
permission update commit and abort.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/file-posix.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)
diff mbox series

Patch

diff --git a/block/file-posix.c b/block/file-posix.c
index db4cccbe51..1cf4ee49eb 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -815,6 +815,18 @@  static int raw_handle_perm_lock(BlockDriverState *bs,
 
     switch (op) {
     case RAW_PL_PREPARE:
+        if ((s->perm | new_perm) == s->perm &&
+            (s->shared_perm & new_shared) == s->shared_perm)
+        {
+            /*
+             * We are going to unlock bytes, it should not fail. If it fail due
+             * to some fs-dependent permission-unrelated reasons (which occurs
+             * sometimes on NFS and leads to abort in bdrv_replace_child) we
+             * can't prevent such errors by any check here. And we ignore them
+             * anyway in ABORT and COMMIT.
+             */
+            return 0;
+        }
         ret = raw_apply_lock_bytes(s, s->fd, s->perm | new_perm,
                                    ~s->shared_perm | ~new_shared,
                                    false, errp);