Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches

- NBD server: Fix crashes related to switching between AioContexts
- file-posix: Workaround for discard/write_zeroes on buggy filesystems
- Follow-up fixes for the reopen vs. permission changes
- quorum: Fix error handling for flush
- block-copy: Refactor copy_range handling
- docs: Describe how to use 'null-co' block driver

# gpg: Signature made Wed 02 Jun 2021 14:44:15 BST
# gpg:                using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg:                issuer "kwolf@redhat.com"
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream:
  docs/secure-coding-practices: Describe how to use 'null-co' block driver
  block-copy: refactor copy_range handling
  block-copy: fix block_copy_task_entry() progress update
  nbd/server: Use drained block ops to quiesce the server
  block-backend: add drained_poll
  block: improve permission conflict error message
  block: simplify bdrv_child_user_desc()
  block/vvfat: inherit child_vvfat_qcow from child_of_bds
  block: improve bdrv_child_get_parent_desc()
  block-backend: improve blk_root_get_parent_desc()
  block: document child argument of bdrv_attach_child_common()
  block/file-posix: Try other fallbacks after invalid FALLOC_FL_ZERO_RANGE
  block/file-posix: Fix problem with fallocate(PUNCH_HOLE) on GPFS
  block: drop BlockBackendRootState::read_only
  block: drop BlockDriverState::read_only
  block: consistently use bdrv_is_read_only()
  block/vvfat: fix vvfat_child_perm crash
  block/vvfat: child_vvfat_qcow: add .get_parent_aio_context, fix crash
  qemu-io-cmds: assert that we don't have .perm requested in no-blk case
  block/quorum: Provide .bdrv_co_flush instead of .bdrv_co_flush_to_disk

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 12 insertions, 2 deletions

diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
index 998b67186d..e8d862a426 100644
--- a/qemu-io-cmds.c
+++ b/qemu-io-cmds.c
@@ -92,9 +92,19 @@ static int command(BlockBackend *blk, const cmdinfo_t *ct, int argc,
         return -EINVAL;
     }
 
-    /* Request additional permissions if necessary for this command. The caller
+    /*
+     * Request additional permissions if necessary for this command. The caller
      * is responsible for restoring the original permissions afterwards if this
-     * is what it wants. */
+     * is what it wants.
+     *
+     * Coverity thinks that blk may be NULL in the following if condition. It's
+     * not so: in init_check_command() we fail if blk is NULL for command with
+     * both CMD_FLAG_GLOBAL and CMD_NOFILE_OK flags unset. And in
+     * qemuio_add_command() we assert that command with non-zero .perm field
+     * doesn't set this flags. So, the following assertion is to silence
+     * Coverity:
+     */
+    assert(blk || !ct->perm);
     if (ct->perm && blk_is_available(blk)) {
         uint64_t orig_perm, orig_shared_perm;
         blk_get_perm(blk, &orig_perm, &orig_shared_perm);