file-posix: Update open_flags in raw_set_perm()

raw_check_perm() + raw_set_perm() can change the flags associated with
the current FD.  If so, we have to update BDRVRawState.open_flags
accordingly.  Otherwise, we may keep reopening the FD even though the
current one already has the correct flags.
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

block/file-posix.c

@@ -146,6 +146,7 @@ typedef struct BDRVRawState {
     uint64_t locked_shared_perm;
 
     int perm_change_fd;
+    int perm_change_flags;
     BDRVReopenState *reopen_state;
 
 #ifdef CONFIG_XFS
@@ -2788,6 +2789,7 @@ static int raw_check_perm(BlockDriverState *bs, uint64_t perm, uint64_t shared,
         assert(s->reopen_state->shared_perm == shared);
         rs = s->reopen_state->opaque;
         s->perm_change_fd = rs->fd;
+        s->perm_change_flags = rs->open_flags;
     } else {
         /* We may need a new fd if auto-read-only switches the mode */
         ret = raw_reconfigure_getfd(bs, bs->open_flags, &open_flags, perm,
@@ -2796,6 +2798,7 @@ static int raw_check_perm(BlockDriverState *bs, uint64_t perm, uint64_t shared,
             return ret;
         } else if (ret != s->fd) {
             s->perm_change_fd = ret;
+            s->perm_change_flags = open_flags;
         }
     }
 
@@ -2834,6 +2837,7 @@ static void raw_set_perm(BlockDriverState *bs, uint64_t perm, uint64_t shared)
     if (s->perm_change_fd && s->fd != s->perm_change_fd) {
         qemu_close(s->fd);
         s->fd = s->perm_change_fd;
+        s->open_flags = s->perm_change_flags;
     }
     s->perm_change_fd = 0;