qemu-e2k/block
Nir Soffer a2b333c018 block: nbd: Fix convert qcow2 compressed to nbd
When converting to qcow2 compressed format, the last step is a special
zero length compressed write, ending in a call to bdrv_co_truncate(). This
call always fails for the nbd driver since it does not implement
bdrv_co_truncate().

For block devices, which have the same limits, the call succeeds since
the file driver implements bdrv_co_truncate(). If the caller asked to
truncate to the same or smaller size with exact=false, the truncate
succeeds. Implement the same logic for nbd.

Example failing without this change:

In one shell start qemu-nbd:

$ truncate -s 1g test.tar
$ qemu-nbd --socket=/tmp/nbd.sock --persistent --format=raw --offset 1536 test.tar

In another shell convert an image to qcow2 compressed via NBD:

$ echo "disk data" > disk.raw
$ truncate -s 1g disk.raw
$ qemu-img convert -f raw -O qcow2 -c disk1.raw nbd+unix:///?socket=/tmp/nbd.sock; echo $?
1

qemu-img failed, but the conversion was successful:

$ qemu-img info nbd+unix:///?socket=/tmp/nbd.sock
image: nbd+unix://?socket=/tmp/nbd.sock
file format: qcow2
virtual size: 1 GiB (1073741824 bytes)
...

$ qemu-img check nbd+unix:///?socket=/tmp/nbd.sock
No errors were found on the image.
1/16384 = 0.01% allocated, 100.00% fragmented, 100.00% compressed clusters
Image end offset: 393216

$ qemu-img compare disk.raw nbd+unix:///?socket=/tmp/nbd.sock
Images are identical.

Fixes: https://bugzilla.redhat.com/1860627
Signed-off-by: Nir Soffer <nsoffer@redhat.com>
Message-Id: <20200727215846.395443-2-nsoffer@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
[eblake: typo fixes]
Signed-off-by: Eric Blake <eblake@redhat.com>
2020-07-28 09:54:19 -05:00
..
monitor blockdev: Split off basic bitmap operations for qemu-img 2020-05-19 10:32:14 -05:00
Makefile.objs Remove VXHS block device 2020-07-17 14:20:57 +02:00
accounting.c block: add empty account cookie type 2019-10-10 10:56:18 +02:00
aio_task.c block: introduce aio task pool 2019-10-10 10:56:17 +02:00
amend.c block/amend: Check whether the node exists 2020-07-27 12:37:25 +02:00
backup-top.c block: Drop @child_class from bdrv_child_perm() 2020-05-18 19:05:25 +02:00
backup-top.h block: introduce backup-top filter driver 2019-10-10 10:56:18 +02:00
backup.c backup: Make sure that source and target size match 2020-05-08 13:26:35 +02:00
blkdebug.c error: Eliminate error_propagate() with Coccinelle, part 2 2020-07-10 15:18:08 +02:00
blklogwrites.c error: Eliminate error_propagate() with Coccinelle, part 2 2020-07-10 15:18:08 +02:00
blkreplay.c block: Use bdrv_default_perms() 2020-05-18 19:05:25 +02:00
blkverify.c error: Eliminate error_propagate() with Coccinelle, part 2 2020-07-10 15:18:08 +02:00
block-backend.c block: fix bdrv_aio_cancel() for ENOMEDIUM requests 2020-07-21 12:00:38 +02:00
block-copy.c block/block-copy: block_copy_dirty_clusters: fix failure check 2020-07-06 08:33:06 +02:00
bochs.c block: Use bdrv_default_perms() 2020-05-18 19:05:25 +02:00
cloop.c block: Use bdrv_default_perms() 2020-05-18 19:05:25 +02:00
commit.c block: Drop @child_class from bdrv_child_perm() 2020-05-18 19:05:25 +02:00
copy-on-read.c block: Drop @child_class from bdrv_child_perm() 2020-05-18 19:05:25 +02:00
create.c block/create: Do not abort if a block driver is not available 2019-09-13 12:18:37 +02:00
crypto.c block/crypto: disallow write sharing by default 2020-07-21 10:49:02 +02:00
crypto.h block/crypto: implement the encryption key management 2020-07-06 08:49:28 +02:00
curl.c error: Eliminate error_propagate() with Coccinelle, part 1 2020-07-10 15:18:08 +02:00
dirty-bitmap.c block/dirty-bitmap: add bdrv_has_named_bitmaps helper 2020-05-28 13:15:22 -05:00
dmg-bz2.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
dmg-lzfse.c block: adding lzfse decompressing support as a module. 2018-12-14 11:52:40 +01:00
dmg.c block: Use bdrv_default_perms() 2020-05-18 19:05:25 +02:00
dmg.h Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
file-posix.c file-posix: Handle `EINVAL` fallocate return value 2020-07-21 16:28:57 +02:00
file-win32.c error: Eliminate error_propagate() with Coccinelle, part 2 2020-07-10 15:18:08 +02:00
filter-compress.c block: Use bdrv_default_perms() 2020-05-18 19:05:25 +02:00
gluster.c error: Reduce unnecessary error propagation 2020-07-10 15:18:08 +02:00
io.c block: drop unallocated_blocks_are_zero 2020-07-06 10:34:14 +02:00
io_uring.c io_uring: use io_uring_cq_ready() to check for ready cqes 2020-06-05 09:54:48 +01:00
iscsi-opts.c Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
iscsi.c iscsi: return -EIO when sense fields are meaningless 2020-07-10 18:02:23 -04:00
linux-aio.c misc: Replace zero-length arrays with flexible array member (automatic) 2020-03-16 22:07:42 +01:00
mirror.c block: Drop @child_class from bdrv_child_perm() 2020-05-18 19:05:25 +02:00
nbd.c block: nbd: Fix convert qcow2 compressed to nbd 2020-07-28 09:54:19 -05:00
nfs.c qapi: Smooth another visitor error checking pattern 2020-07-10 15:18:08 +02:00
null.c replay: add BH oneshot event for block layer 2019-10-14 17:12:48 +02:00
nvme.c block/nvme: support nested aio_poll() 2020-06-23 15:46:08 +01:00
parallels.c error: Avoid error_propagate() after migrate_add_blocker() 2020-07-10 15:18:08 +02:00
parallels.h Clean up includes 2018-02-09 05:05:11 +01:00
qapi-sysemu.c block: Move system emulator QMP commands to block/qapi-sysemu.c 2020-03-06 17:15:38 +01:00
qapi.c block: Fix VM size field width in snapshot dump 2020-02-20 16:43:42 +01:00
qcow.c qcow: Tolerate backing_fmt= 2020-07-14 15:18:59 +02:00
qcow2-bitmap.c qcow2: Tweak comments on qcow2_get_persistent_dirty_bitmap_size 2020-06-17 14:53:39 +02:00
qcow2-cache.c core: replace getpagesize() with qemu_real_host_page_size 2019-10-26 15:38:06 +02:00
qcow2-cluster.c qcow2: Implement v2 zero writes with discard if possible 2020-07-21 16:28:57 +02:00
qcow2-refcount.c block: Comment cleanups 2020-05-05 13:17:36 +02:00
qcow2-snapshot.c qcow2: Allow resize of images with internal snapshots 2020-05-05 13:17:36 +02:00
qcow2-threads.c qcow2: add zstd cluster compression 2020-05-13 14:20:31 +02:00
qcow2.c block: Add support to warn on backing file change without format 2020-07-14 15:18:59 +02:00
qcow2.h qcow2: Expose bitmaps' size during measure 2020-05-28 13:16:16 -05:00
qed-check.c block/qed: add missed coroutine_fn markers 2019-04-30 15:29:00 +02:00
qed-cluster.c qed: protect table cache with CoMutex 2017-07-17 11:34:11 +08:00
qed-l2-cache.c qed: protect table cache with CoMutex 2017-07-17 11:34:11 +08:00
qed-table.c block/qed: add missed coroutine_fn markers 2019-04-30 15:29:00 +02:00
qed.c qapi: Smooth another visitor error checking pattern 2020-07-10 15:18:08 +02:00
qed.h qed: Simplify backing reads 2020-07-06 10:34:14 +02:00
quorum.c error: Reduce unnecessary error propagation 2020-07-10 15:18:08 +02:00
raw-format.c error: Eliminate error_propagate() with Coccinelle, part 2 2020-07-10 15:18:08 +02:00
rbd.c qapi: Smooth another visitor error checking pattern 2020-07-10 15:18:08 +02:00
replication.c error: Reduce unnecessary error propagation 2020-07-10 15:18:08 +02:00
sheepdog.c sheepdog: Add trivial backing_fmt support 2020-07-14 15:18:59 +02:00
snapshot.c block/snapshot: rename Error ** parameter to more common errp 2019-12-18 08:43:19 +01:00
ssh.c qapi: Smooth another visitor error checking pattern 2020-07-10 15:18:08 +02:00
stream.c block: Add support to warn on backing file change without format 2020-07-14 15:18:59 +02:00
throttle-groups.c qom: Change object_get_canonical_path_component() not to malloc 2020-07-21 16:23:43 +02:00
throttle.c error: Eliminate error_propagate() with Coccinelle, part 2 2020-07-10 15:18:08 +02:00
trace-events Remove VXHS block device 2020-07-17 14:20:57 +02:00
vdi.c error: Avoid error_propagate() after migrate_add_blocker() 2020-07-10 15:18:08 +02:00
vhdx-endian.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
vhdx-log.c block: Add flags to bdrv(_co)_truncate() 2020-04-30 17:51:07 +02:00
vhdx.c error: Avoid error_propagate() after migrate_add_blocker() 2020-07-10 15:18:08 +02:00
vhdx.h block/vhdx: Use IEC binary prefixes for size constants 2019-04-30 15:29:00 +02:00
vmdk.c vmdk: Add trivial backing_fmt support 2020-07-14 15:18:59 +02:00
vpc.c error: Avoid error_propagate() after migrate_add_blocker() 2020-07-10 15:18:08 +02:00
vvfat.c error: Avoid error_propagate() after migrate_add_blocker() 2020-07-10 15:18:08 +02:00
win32-aio.c Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
write-threshold.c qapi: Drop qapi_event_send_FOO()'s Error ** argument 2018-08-28 18:21:38 +02:00