File 0191-block-file-posix-do-not-fail-on-unl.patch of Package qemu-linux-user.20749

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File 0191-block-file-posix-do-not-fail-on-unl.patch of Package qemu-linux-user.20749

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Date: Fri, 29 Mar 2019 14:04:54 +0300
Subject: block/file-posix: do not fail on unlock bytes

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>
(cherry picked from commit 696aaaed579ac5bf5fa336216909b46d3d8f07a8)
[LY: BSC#1119115]
Signed-off-by: Liang Yan <lyan@suse.com>
---
 block/file-posix.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/block/file-posix.c b/block/file-posix.c
index 2bcf1e4344f74ff989671a2bd20d..982d09aeb2b805fa71f9077692bf 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -770,6 +770,18 @@ 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->lock_fd, s->perm | new_perm,
                                    ~s->shared_perm | ~new_shared,
                                    false, errp);

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File 0191-block-file-posix-do-not-fail-on-unl.patch of Package qemu-linux-user.20749

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