qemu-e2k/block
Alberto Garcia 80f5c01183 qcow2: Forbid discard in qcow2 v2 images with backing files
A discard request deallocates the selected clusters so they read back
as zeroes. This is done by clearing the cluster offset field and
setting QCOW_OFLAG_ZERO in the L2 entry.

This flag is however only supported when qcow_version >= 3. In older
images the cluster is simply deallocated, exposing any possible stale
data from the backing file.

Since discard is an advisory operation it's safer to simply forbid it
in this scenario.

Note that we are adding this check to qcow2_co_pdiscard() and not to
qcow2_cluster_discard() or discard_in_l2_slice() because the last
two are also used by qcow2_snapshot_create() to discard the clusters
used by the VM state. In this case there's no risk of exposing stale
data to the guest and we really want that the clusters are always
discarded.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-Id: <20200331114345.29993-1-berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-04-07 13:51:09 +02:00
..
monitor Use &error_abort instead of separate assert() 2020-03-17 16:05:40 +01:00
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
backup-top.c block/block-copy: hide structure definitions 2020-03-11 12:42:30 +01:00
backup-top.h block: introduce backup-top filter driver 2019-10-10 10:56:18 +02:00
backup.c block/block-copy: hide structure definitions 2020-03-11 12:42:30 +01:00
blkdebug.c blkdebug: Allow taking/unsharing permissions 2020-01-06 13:43:06 +01:00
blklogwrites.c Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
blkreplay.c block: implement bdrv_snapshot_goto for blkreplay 2019-10-14 17:12:48 +02:00
blkverify.c block: Remove bdrv_recurse_is_first_non_filter() 2020-02-18 11:55:40 +01:00
block-backend.c block: Add @exact parameter to bdrv_co_truncate() 2019-10-28 12:00:07 +01:00
block-copy.c block/block-copy: hide structure definitions 2020-03-11 12:42:30 +01:00
bochs.c block: Use QEMU_IS_ALIGNED 2019-09-16 14:48:30 +02:00
cloop.c block: Use QEMU_IS_ALIGNED 2019-09-16 14:48:30 +02:00
commit.c commit: Fix is_read for block_job_error_action() 2020-02-18 10:53:56 +01:00
copy-on-read.c block: Remove bdrv_recurse_is_first_non_filter() 2020-02-18 11:55:40 +01:00
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: pass BlockDriver reference to the .bdrv_co_create 2020-03-26 14:44:33 +01:00
crypto.h Clean up ill-advised or unusual header guards 2019-05-13 08:58:55 +02:00
curl.c block/curl: HTTP header field names are case insensitive 2020-03-11 12:42:29 +01:00
dirty-bitmap.c block/dirty-bitmap: improve _next_dirty_area API 2020-03-18 14:03:46 -04:00
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 QEMU_IS_ALIGNED 2019-09-16 14:48:30 +02:00
dmg.h Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
file-posix.c block: trickle down the fallback image creation function use to the block drivers 2020-03-26 14:44:33 +01:00
file-win32.c block: pass BlockDriver reference to the .bdrv_co_create 2020-03-26 14:44:33 +01:00
filter-compress.c block: Remove bdrv_recurse_is_first_non_filter() 2020-02-18 11:55:40 +01:00
gluster.c block: pass BlockDriver reference to the .bdrv_co_create 2020-03-26 14:44:33 +01:00
io_uring.c block/io_uring: Remove superfluous semicolon 2020-02-18 10:54:02 +01:00
io.c block/io: fix bdrv_co_do_copy_on_readv 2020-03-16 11:46:11 +00:00
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 block/iscsi:use the flags in iscsi_open() prevent Clang warning 2020-03-27 14:47:23 +01:00
linux-aio.c misc: Replace zero-length arrays with flexible array member (automatic) 2020-03-16 22:07:42 +01:00
Makefile.objs monitor/hmp: rename device-hotplug.c to block/monitor/block-hmp-cmds.c 2020-03-09 18:05:31 +00:00
mirror.c mirror: Wait only for in-flight operations 2020-03-27 14:47:23 +01:00
nbd.c block: trickle down the fallback image creation function use to the block drivers 2020-03-26 14:44:33 +01:00
nfs.c block: pass BlockDriver reference to the .bdrv_co_create 2020-03-26 14:44:33 +01:00
null.c replay: add BH oneshot event for block layer 2019-10-14 17:12:48 +02:00
nvme.c block: trickle down the fallback image creation function use to the block drivers 2020-03-26 14:44:33 +01:00
parallels.c block: pass BlockDriver reference to the .bdrv_co_create 2020-03-26 14:44:33 +01:00
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
qcow2-bitmap.c block/qcow2-bitmap: use bdrv_dirty_bitmap_next_dirty 2020-03-18 14:03:46 -04:00
qcow2-cache.c core: replace getpagesize() with qemu_real_host_page_size 2019-10-26 15:38:06 +02:00
qcow2-cluster.c qcow2: Fix alloc_cluster_abort() for pre-existing clusters 2020-03-06 17:15:37 +01:00
qcow2-refcount.c qcow2: update_refcount(): Reset old_table_index after qcow2_cache_put() 2020-02-18 10:53:56 +01:00
qcow2-snapshot.c qcow2: Don't round the L1 table allocation up to the sector size 2020-02-06 13:47:45 +01:00
qcow2-threads.c block/qcow2-threads: fix qcow2_decompress 2020-03-11 12:42:30 +01:00
qcow2.c qcow2: Forbid discard in qcow2 v2 images with backing files 2020-04-07 13:51:09 +02:00
qcow2.h qcow2: Remove unused fields from BDRVQcow2State 2020-03-27 14:47:23 +01:00
qcow.c block: pass BlockDriver reference to the .bdrv_co_create 2020-03-26 14:44:33 +01:00
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 block: pass BlockDriver reference to the .bdrv_co_create 2020-03-26 14:44:33 +01:00
qed.h block/qed: add missed coroutine_fn markers 2019-04-30 15:29:00 +02:00
quorum.c quorum: Stop marking it as a filter 2020-02-18 11:55:40 +01:00
raw-format.c block: pass BlockDriver reference to the .bdrv_co_create 2020-03-26 14:44:33 +01:00
rbd.c block: pass BlockDriver reference to the .bdrv_co_create 2020-03-26 14:44:33 +01:00
replication.c block/replication.c: Ignore requests after failover 2020-03-03 18:04:47 +08:00
sheepdog.c sheepdog: Consistently set bdrv_has_zero_init_truncate 2020-03-26 14:44:33 +01:00
snapshot.c block/snapshot: rename Error ** parameter to more common errp 2019-12-18 08:43:19 +01:00
ssh.c block: pass BlockDriver reference to the .bdrv_co_create 2020-03-26 14:44:33 +01:00
stream.c block/stream: Remove redundant statement in stream_run() 2020-03-09 15:59:31 +01:00
throttle-groups.c throttle-groups: fix memory leak in throttle_group_set_limit: 2020-01-06 13:43:06 +01:00
throttle.c block: Remove bdrv_recurse_is_first_non_filter() 2020-02-18 11:55:40 +01:00
trace-events block/block-copy: use block_status 2020-03-11 12:42:30 +01:00
vdi.c block: pass BlockDriver reference to the .bdrv_co_create 2020-03-26 14:44:33 +01:00
vhdx-endian.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
vhdx-log.c block: Add @exact parameter to bdrv_co_truncate() 2019-10-28 12:00:07 +01:00
vhdx.c block: pass BlockDriver reference to the .bdrv_co_create 2020-03-26 14:44:33 +01:00
vhdx.h block/vhdx: Use IEC binary prefixes for size constants 2019-04-30 15:29:00 +02:00
vmdk.c block: pass BlockDriver reference to the .bdrv_co_create 2020-03-26 14:44:33 +01:00
vpc.c block: pass BlockDriver reference to the .bdrv_co_create 2020-03-26 14:44:33 +01:00
vvfat.c block/vvfat: Do not unref qcow on closing backing bdrv 2020-02-18 10:53:56 +01:00
vxhs.c replay: add BH oneshot event for block layer 2019-10-14 17:12:48 +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