Format drivers such as qcow2 don't allow sharing the same image between
two QEMU instances in order to prevent image corruptions, because of
metadata cache. LUKS driver don't modify metadata except for when
creating image, so it is safe to relax the permission. This makes
share-rw=on property work on virtual devices.
Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Commit 6fccbb475b fixed a bug caused by
QEMU attempting to remove a throttle group member with no pending
requests but an active timer set. This was the result of a previous
bdrv_drained_begin() call processing the throttled requests but
leaving the timer untouched.
Although the commit does solve the problem, the situation shouldn't
happen in the first place. If we try to drain a throttle group member
which has a timer set, we should cancel the timer instead of ignoring
it.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
In the throttling code after an I/O request has been completed the
next one is selected from a different member using a round-robin
algorithm. This ensures that all members get a chance to finish their
pending I/O requests.
However, if a group member has its I/O limits disabled (because it's
being drained) then we should always give it priority in order to have
all its pending requests finished as soon as possible.
If we don't do this we could have a member in the process of being
drained waiting for the throttled requests of other members, for which
the I/O limits still apply.
This can have additional consequences: if we're running in qtest mode
(with QEMU_CLOCK_VIRTUAL) then timers can only fire if we advance the
clock manually, so attempting to drain a block device can hang QEMU in
the BDRV_POLL_WHILE() loop at the end of bdrv_do_drained_begin().
Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
For BlockBackends that are skipped in query-blockstats, we would leak
info since commit 567dcb31. Allocate info only later to avoid the memory
leak.
Fixes: CID 1394727
Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Consistent with query-block, query-blockstats should not only include
named BlockBackends, but also those that are anonymous, but belong to a
device model.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Like for query-block, the client needs to identify which BlockBackend
the returned data is for. Anonymous BlockBackends are identified by the
device model they are attached to. Add a 'qdev' field that contains the
qdev ID or QOM path of the attached device model.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
The BLKDISCARD ioctl doesn't guarantee that the discarded blocks read as
all-zero afterwards, so don't try to abuse it for zero writing. We try
to only use this if BLKDISCARDZEROES tells us that it is safe, but this
is unreliable on older kernels and a constant 0 in newer kernels. In
other words, this code path is never actually used with newer kernels,
so we don't even try to unmap while writing zeros.
This patch removes the abuse of discard for writing zeroes from
file-posix and instead adds a new function that uses interfaces that are
actually meant to deallocate and zero out at the same time. Only if
those fail, it falls back to zeroing out without unmap. We never fall
back to a discard operation any more that may or may not result in
zeros.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Since 42a3e1ab36 qemu asserts when using the
vvfat driver:
git clone git://qemu.org/qemu.git
cd qemu
./configure --target-list=ppc-softmmu --enable-debug
make -j8
mkdir foo
touch foo/hello
./ppc-softmmu/qemu-system-ppc -M prep --nographic --monitor null \
-hda fat:rw:./foo
"Ctrl-C"
qemu-system-ppc: block.c:3368: bdrv_close_all: Assertion \
`((&all_bdrv_states)->tqh_first == ((void *)0))' failed.
This is because we reference bs twice in qcow_co_create(..) one time in
bdrv_open_blockdev_ref(..) and in blk_insert_bs(..) but we unref it only once
in blk_unref which leads to the reference leak.
Note that I didn't tested much QCOW after this change as I don't use it much.
Signed-off-by: KONRAD Frederic <frederic.konrad@adacore.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
qstring_from_substr() takes the index of the substring's first and
last character. qstring_from_substr(s, 0, SIZE_MAX) denotes an empty
substring. Awkward.
Shift the end index one to the right. This simplifies both
qstring_from_substr() and its callers.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180727062204.10401-3-armbru@redhat.com>
In ed6e2161 ("linux-aio: properly bubble up errors from initialzation"),
I only added a bdrv_attach_aio_context callback for the bdrv_file
driver. There are several other drivers that use the shared
aio_plug callback, though, and they will trip the assertion added to
aio_get_linux_aio because they did not call aio_setup_linux_aio first.
Add the appropriate callback definition to the affected driver
definitions.
Fixes: ed6e2161 ("linux-aio: properly bubble up errors from initialization")
Reported-by: Farhan Ali <alifm@linux.ibm.com>
Signed-off-by: Nishanth Aravamudan <naravamudan@digitalocean.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 20180718211256.29774-1-naravamudan@digitalocean.com
Cc: Eric Blake <eblake@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: John Snow <jsnow@redhat.com>
Cc: Max Reitz <mreitz@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Fam Zheng <famz@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-block@nongnu.org
Cc: qemu-devel@nongnu.org
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
It's annoying to see this debug message every time you use vvfat.
Disable it with the DLOG() macro by default, as it is done with the
other debug messages in this file.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Throttle groups consist of members sharing one throttling state
(including bps/iops limits). Round-robin scheduling is used to ensure
fairness. If a group member already has a timer pending then other
groups members do not schedule their own timers. The next group member
will have its turn when the existing timer expires.
A hang may occur when a group member leaves while it had a timer
scheduled. Although the code carefully removes the group member from
the round-robin list, it does not schedule the next member. Therefore
remaining members continue to wait for the removed member's timer to
expire.
This patch schedules the next request if a timer is pending.
Unfortunately the actual bug is a race condition that I've been unable
to capture in a test case.
Sometimes drive2 hangs when drive1 is removed from the throttling group:
$ qemu ... -drive if=none,id=drive1,cache=none,format=qcow2,file=data1.qcow2,iops=100,group=foo \
-device virtio-blk-pci,id=virtio-blk-pci0,drive=drive1 \
-drive if=none,id=drive2,cache=none,format=qcow2,file=data2.qcow2,iops=10,group=foo \
-device virtio-blk-pci,id=virtio-blk-pci1,drive=drive2
(guest-console1)# fio -filename /dev/vda 4k-seq-read.job
(guest-console2)# fio -filename /dev/vdb 4k-seq-read.job
(qmp) {"execute": "block_set_io_throttle", "arguments": {"device": "drive1","bps": 0,"bps_rd": 0,"bps_wr": 0,"iops": 0,"iops_rd": 0,"iops_wr": 0}}
Reported-by: Nini Gu <ngu@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20180704145410.794-1-stefanha@redhat.com
RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=1535914
Cc: Alberto Garcia <berto@igalia.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Adjust each caller of raw_open_common to specify if they are expecting
host and character devices or not. Tighten expectations of file types upon
open in the common code and refuse types that are not expected.
This has two effects:
(1) Character and block devices are now considered deprecated for the
'file' driver, which expects only S_IFREG, and
(2) no file-posix driver (file, host_cdrom, or host_device) can open
directories now.
I don't think there's a legitimate reason to open directories as if
they were files. This prevents QEMU from opening and attempting to probe
a directory inode, which can break in exciting ways. One of those ways
is lseek on ext4/xfs, which will return 0x7fffffffffffffff as the file
size instead of EISDIR. This can coax QEMU into responding with a
confusing "file too big" instead of "Hey, that's not a file".
See: https://bugs.launchpad.net/qemu/+bug/1739304/
Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Truncation is the last to convert from open coded req handling to
reusing helpers. This time the permission check in prepare has to adapt
to the new caller: it checks a different permission bit, and doesn't
trigger the before write notifier.
Also, truncation should always trigger a bs->total_sectors update and in
turn call parent resize_cb. Update the condition in finish helper, too.
It's intended to do a duplicated bs->read_only check before calling
bdrv_co_write_req_prepare() so that we can be more informative with the
error message, as bdrv_co_write_req_prepare() doesn't have Error
parameter.
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
If we are growing the image and potentially using preallocation for the
new area, we need to make sure that no write requests are made to the
"preallocated" area which is [@old_size, @offset), not
[@offset, offset * 2 - @old_size).
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This brings the request handling logic inline with write and discard,
fixing write_gen, resize_cb, dirty bitmaps and image size refreshing.
The last of these issues broke iotest case 222, which is now fixed.
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reuse the new bdrv_co_write_req_prepare/finish helpers. The variation
here is that discard requests don't affect bs->wr_highest_offset, and it
cannot extend the image.
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Two problems exist when a write request that enlarges the image (i.e.
write beyond EOF) finishes:
1) parent is not notified about size change;
2) dirty bitmap is not resized although we try to set the dirty bits;
Fix them just like how bdrv_co_truncate works.
Reported-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
As a mechanical refactoring patch, this is the first step towards
unified and more correct write code paths. This is helpful because
multiple BlockDriverState fields need to be updated after modifying
image data, and it's hard to maintain in multiple places such as copy
offload, discard and truncate.
Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This matches the types used for bytes in the rest parts of block layer.
In the case of bdrv_co_truncate, new_bytes can be the image size which
probably doesn't fit in a 32 bit int.
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Other I/O functions are already using a BdrvChild pointer in the API, so
make discard do the same. It makes it possible to initiate the same
permission checks before doing I/O, and much easier to share the
helper functions for this, which will be added and used by write,
truncate and copy range paths.
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
A few trace points that can help reveal what is happening in a copy
offloading I/O path.
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
With in one module, trace points usually have a common prefix named
after the module name. paio_submit and paio_submit_co are the only two
trace points so far in the two file protocol drivers. As we are adding
more, having a common prefix here is better so that trace points can be
enabled with a glob. Rename them.
Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This reverts commit b008326744.
Hold off removing this for one more QEMU release (current libvirt
release still uses it.)
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The sector size needs to be large enough to accommodate the data
structures for the log super block and log write entries. This was
previously not properly checked, which made it possible to cause
QEMU to badly misbehave.
Signed-off-by: Ari Sundholm <ari@tuxera.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Fleecing scheme works as follows: we want a kind of temporary snapshot
of active drive A. We create temporary image B, with B->backing = A.
Then we start backup(sync=none) from A to B. From this point, B reads
as point-in-time snapshot of A (A continues to be active drive,
accepting guest IO).
This scheme needs some additional synchronization between reads from B
and backup COW operations, otherwise, the following situation is
theoretically possible:
(assume B is qcow2, client is NBD client, reading from B)
1. client starts reading and take qcow2 mutex in qcow2_co_preadv, and
goes up to l2 table loading (assume cache miss)
2) guest write => backup COW => qcow2 write =>
try to take qcow2 mutex => waiting
3. l2 table loaded, we see that cluster is UNALLOCATED, go to
"case QCOW2_CLUSTER_UNALLOCATED" and unlock mutex before
bdrv_co_preadv(bs->backing, ...)
4) aha, mutex unlocked, backup COW continues, and we finally finish
guest write and change cluster in our active disk A
5. actually, do bdrv_co_preadv(bs->backing, ...) and read
_new updated_ data.
To avoid this, let's make backup writes serializing, to not intersect
with reads from B.
Note: we expand range of handled cases from (sync=none and
B->backing = A) to just (A in backing chain of B), to finally allow
safe reading from B during backup for all cases when A in backing chain
of B, i.e. B formally looks like point-in-time snapshot of A.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Serialized writes should be used in copy-on-write of backup(sync=none)
for image fleecing scheme.
We need to change an assert in bdrv_aligned_pwritev, added in
28de2dcd88. The assert may fail now, because call to
wait_serialising_requests here may become first call to it for this
request with serializing flag set. It occurs if the request is aligned
(otherwise, we should already set serializing flag before calling
bdrv_aligned_pwritev and correspondingly waited for all intersecting
requests). However, for aligned requests, we should not care about
outdating of previously read data, as there no such data. Therefore,
let's just update an assert to not care about aligned requests.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Pass read flags and write flags separately. This is needed to handle
coming BDRV_REQ_NO_SERIALISING clearly in following patches.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Here two things are fixed:
1. Architecture
On each recursion step, we go to the child of src or dst, only for one
of them. So, it's wrong to create tracked requests for both on each
step. It leads to tracked requests duplication.
2. Wait for serializing requests on write path independently of
BDRV_REQ_NO_SERIALISING
Before commit 9ded4a0114 "backup: Use copy offloading",
BDRV_REQ_NO_SERIALISING was used for only one case: read in
copy-on-write operation during backup. Also, the flag was handled only
on read path (in bdrv_co_preadv and bdrv_aligned_preadv).
After 9ded4a0114, flag is used for not waiting serializing operations
on backup target (in same case of copy-on-write operation). This
behavior change is unsubstantiated and potentially dangerous, let's
drop it and add additional asserts and documentation.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
If the virtual disk size isn't aligned to full clusters,
bdrv_co_do_copy_on_readv() may get pnum == 0 before having the full
cluster completed, which will let it run into an assertion failure:
qemu-io: block/io.c:1203: bdrv_co_do_copy_on_readv: Assertion `skip_bytes < pnum' failed.
Check for EOF, assert that we read at least as much as the read request
originally wanted to have (which is true at EOF because otherwise
bdrv_check_byte_request() would already have returned an error) and
return success early even though we couldn't copy the full cluster.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Commit dcf94a23b1 ('block: Don't poll in parent drain callbacks')
removed polling in bdrv_child_cb_drained_begin() on the grounds that the
original bdrv_drain() already will poll and BdrvChildRole.drained_begin
calls must not cause graph changes (and therefore must not call
aio_poll() or the recursion through the graph will break.
This reasoning is correct for calls through bdrv_do_drained_begin().
However, BdrvChildRole.drained_begin is also called when a node that is
already in a drained section (i.e. bdrv_do_drained_begin() has already
returned and therefore can't poll any more) is attached to a new parent.
In this case, we must explicitly poll to have all requests completed
before the drained new child can be attached to the parent.
In bdrv_replace_child_noperm(), we know that we're not inside the
recursion of bdrv_do_drained_begin() because graph changes are not
allowed there, and bdrv_replace_child_noperm() is a graph change. The
call of BdrvChildRole.drained_begin() must therefore be followed by a
BDRV_POLL_WHILE() that waits for the completion of requests.
Reported-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
VMDK performs a probing check in vmdk_co_create_opts() to prevent the
user from assigning non-VMDK files as a backing file, because it only
supports VMDK backing files. However, with the @backing runtime option,
it is possible to assign arbitrary nodes as backing nodes, regardless of
what the image header says. Therefore, VMDK may not just access backing
nodes assuming they are VMDK nodes -- which it does, because it needs to
compare the backing file's CID with the overlay's parentCID value, and
naturally the backing file only has a CID when it's a VMDK file.
Instead, it should report the CID of non-VMDK backing files not to match
the overlay because clearly a non-present CID does not match.
Without this change, vmdk_read_cid() reads from the backing file's
bs->file, which may be NULL (in which case we get a segfault). Also, it
interprets bs->opaque as a BDRVVmdkState and then reads from the
.desc_offset field, which usually will just return some arbitrary value
which then results in either garbage to be read, or bdrv_pread() to
return an error, both of which result in a non-matching CID to be
reported.
(In a very unlikely case, we could read something that looks like a
VMDK descriptor, and then get a CID which might actually match. But
that is highly unlikely, and the only result would be that VMDK accepts
the backing file which is not too bad (albeit unintentional).)
((And in theory, the seek to .desc_offset might leak data from another
block driver's opaque object. But then again, the user should realize
very quickly that a non-VMDK backing file does not work (because the
read will very likely fail, due to the reasons given above), so this
should not be exploitable.))
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20180702210721.4847-2-mreitz@redhat.com
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
One of them is a typo. But update both to be more readable.
Reported-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Message-id: 20180702025836.20957-3-famz@redhat.com
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
- qcow2: Use worker threads for compression to improve performance of
'qemu-img convert -W' and compressed backup jobs
- blklogwrites: New filter driver to log write requests to an image in
the dm-log-writes format
- file-posix: Fix image locking during image creation
- crypto: Fix memory leak in error path
- Error out instead of silently truncating node names
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Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging
Block layer patches:
- qcow2: Use worker threads for compression to improve performance of
'qemu-img convert -W' and compressed backup jobs
- blklogwrites: New filter driver to log write requests to an image in
the dm-log-writes format
- file-posix: Fix image locking during image creation
- crypto: Fix memory leak in error path
- Error out instead of silently truncating node names
# gpg: Signature made Thu 05 Jul 2018 11:24:33 BST
# gpg: using RSA key 7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6
* remotes/kevin/tags/for-upstream:
file-posix: Unlock FD after creation
file-posix: Fix creation locking
block/blklogwrites: Add an option for the update interval of the log superblock
block/blklogwrites: Add an option for appending to an old log
block/blklogwrites: Change log_sector_size from int64_t to uint64_t
block/crypto: Fix memory leak in create error path
block: Don't silently truncate node names
block: Add blklogwrites
block: Move two block permission constants to the relevant enum
qcow2: add compress threads
qcow2: refactor data compression
qemu-img: allow compressed not-in-order writes
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Closing the FD does not necessarily mean that it is unlocked. Fix this
by relinquishing all permission locks before qemu_close().
Reported-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
raw_apply_lock_bytes() takes a bit mask of "permissions that are NOT
shared".
Also, make the "perm" and "shared" variables uint64_t, because I do not
particularly like using ~ on signed integers (and other permission masks
are usually uint64_t, too).
Reported-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This is a way to ensure that the log superblock is periodically
updated. Before, this was only done on flush requests, which may
not be enough if the VM exits abnormally, omitting the final flush.
The default interval is 4096 write requests.
Signed-off-by: Ari Sundholm <ari@tuxera.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Suggested by Kevin Wolf. May be useful when testing multiple batches
of writes or doing long-term testing involving restarts of the VM.
Signed-off-by: Ari Sundholm <ari@tuxera.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This was a simple oversight when working on intermediate versions
of the original patch which introduced blklogwrites.
Signed-off-by: Ari Sundholm <ari@tuxera.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Implements a block device write logging system, similar to Linux kernel
device mapper dm-log-writes. The write operations that are performed
on a block device are logged to a file or another block device. The
write log format is identical to the dm-log-writes format. Currently,
log markers are not supported.
This functionality can be used for crash consistency and fs consistency
testing. By implementing it in qemu, tests utilizing write logs can be
be used to test non-Linux drivers and older kernels.
The driver accepts an optional parameter to set the sector size used
for logging. This makes the driver require all requests to be aligned
to this sector size and also makes offsets and sizes of writes in the
log metadata to be expressed in terms of this value (the log format has
a granularity of one sector for offsets and sizes). This allows
accurate logging of writes to guest block devices that have unusual
sector sizes.
The implementation is based on the blkverify and blkdebug block
drivers.
Signed-off-by: Aapo Vienamo <aapo@tuxera.com>
Signed-off-by: Ari Sundholm <ari@tuxera.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Do data compression in separate threads. This significantly improve
performance for qemu-img convert with -W (allow async writes) and -c
(compressed) options.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Fam Zheng
Alberto Garcia
Kevin Wolf
Leonid Bloch
KONRAD Frederic
Markus Armbruster
Nishanth Aravamudan
Thomas Huth
Stefan Weil
Stefan Hajnoczi
John Snow
Peter Maydell
Cornelia Huck
Ari Sundholm
Vladimir Sementsov-Ogievskiy
Max Reitz
Aapo Vienamo