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

Block layer patches:

- block: Fix crash with qcow2 partial cluster COW with small cluster
sizes (misaligned write reque

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

Block layer patches:

- block: Fix crash with qcow2 partial cluster COW with small cluster
sizes (misaligned write requests with BDRV_REQ_NO_FALLBACK)
- qcow2: Fix integer overflow potentially causing corruption with huge
requests
- vhdx: Detect truncated image files
- tools: Support help options for --object
- Various block-related replay improvements
- iotests/028: Fix for long $TEST_DIRs

# gpg: Signature made Mon 14 Oct 2019 17:02:54 BST
# gpg: using RSA key 7F09B272C88F2FD6
# 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:
iotests: Test large write request to qcow2 file
qcow2: Limit total allocation range to INT_MAX
qemu-nbd: Support help options for --object
qemu-img: Support help options for --object
qemu-io: Support help options for --object
vl: Split off user_creatable_print_help()
iotests/028: Fix for long $TEST_DIRs
block: Reject misaligned write requests with BDRV_REQ_NO_FALLBACK
replay: add BH oneshot event for block layer
replay: finish record/replay before closing the disks
replay: don't drain/flush bdrv queue while RR is working
replay: update docs for record/replay with block devices
replay: disable default snapshot for record/replay
block: implement bdrv_snapshot_goto for blkreplay
block/vhdx: add check for truncated image files

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

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block: Reject misaligned write requests with BDRV_REQ_NO_FALLBACK

The BDRV_REQ_NO_FALLBACK flag means that an operation should only be
performed if it can be offloaded or otherwise performed efficie

block: Reject misaligned write requests with BDRV_REQ_NO_FALLBACK

The BDRV_REQ_NO_FALLBACK flag means that an operation should only be
performed if it can be offloaded or otherwise performed efficiently.

However a misaligned write request requires a RMW so we should return
an error and let the caller decide how to proceed.

This hits an assertion since commit c8bb23cbdb if the required
alignment is larger than the cluster size:

qemu-img create -f qcow2 -o cluster_size=2k img.qcow2 4G
qemu-io -c "open -o driver=qcow2,file.align=4k blkdebug::img.qcow2" \
-c 'write 0 512'
qemu-io: block/io.c:1127: bdrv_driver_pwritev: Assertion `!(flags & BDRV_REQ_NO_FALLBACK)' failed.
Aborted

The reason is that when writing to an unallocated cluster we try to
skip the copy-on-write part and zeroize it using BDRV_REQ_NO_FALLBACK
instead, resulting in a write request that is too small (2KB cluster
size vs 4KB required alignment).

Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

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