Some users (like block jobs) can tolerate an AioContext change for their
BlockBackend. Add a function that tells the BlockBackend that it can
allow changes.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
bdrv_try_set_aio_context() currently fails if a BlockBackend is attached
to a node because it doesn't implement the BdrvChildRole callbacks for
AioContext management.
We can allow changing the AioContext of monitor-owned BlockBackends as
long as no device is attached to them.
When setting the AioContext of the root node of a BlockBackend, we now
need to pass blk->root as an ignored child because we don't want the
root node to recursively call back into BlockBackend and execute
blk_do_set_aio_context() a second time.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
There are a few places in which we turn a number of bytes into sectors
in order to compare the result against BDRV_REQUEST_MAX_SECTORS
instead of using BDRV_REQUEST_MAX_BYTES directly.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
When an L2 table entry points to a compressed cluster the space used
by the data is specified in 512-byte sectors. This size is independent
from BDRV_SECTOR_SIZE and is specific to the qcow2 file format.
The QCOW2_COMPRESSED_SECTOR_SIZE constant defined in this patch makes
this explicit.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
XFS_IOC_ZERO_RANGE does not increase the file length:
$ touch foo
$ xfs_io -c 'zero 0 65536' foo
$ stat -c "size=%s, blocks=%b" foo
size=0, blocks=128
We do want writes beyond the EOF to automatically increase the file
length, however. This is evidenced by the fact that iotest 061 is
broken on XFS since qcow2's check implementation checks for blocks
beyond the EOF.
Reported-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Leading underscores are ill-advised because such identifiers are
reserved. Trailing underscores are merely ugly. Strip both.
Our header guards commonly end in _H. Normalize the exceptions.
Done with scripts/clean-header-guards.pl.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190315145123.28030-7-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
[Changes to slirp/ dropped, as we're about to spin it off]
The last user of this field disappeared when we replace the
sector-based bdrv_write() with the byte-based bdrv_pwrite().
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
No one is using these functions anymore, all callers have switched to
the byte-based bdrv_pread() and bdrv_pwrite()
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
There's only a couple of bdrv_read() and bdrv_write() calls left in
the vvfat code, and they can be trivially replaced with the byte-based
bdrv_pread() and bdrv_pwrite().
Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
There's only a couple of bdrv_read() and bdrv_write() calls left in
the vdi code, and they can be trivially replaced with the byte-based
bdrv_pread() and bdrv_pwrite().
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
There's only one bdrv_write() call left in the qcow2 code, and it can
be trivially replaced with the byte-based bdrv_pwrite().
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
On a file system used by the customer, fallocate() returns an error
if the block is not properly aligned. So, bdrv_co_pwrite_zeroes()
fails. We can handle that case the same way as it is done for the
unsupported cases, namely, call to bdrv_driver_pwritev() that writes
zeroes to an image for the unaligned chunk of the block.
Suggested-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 1554474244-553661-1-git-send-email-andrey.shinkevich@virtuozzo.com
Message-Id: <1554474244-553661-1-git-send-email-andrey.shinkevich@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This function combines bdrv_set_backing_hd() and bdrv_replace_node()
so we can use it to simplify the code a bit in commit_start().
Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-id: 20190403143748.9790-1-berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
ssh_bdrv_dirname() is basically the generic bdrv_dirname(), except it
takes care not to silently chop off any query string (i.e.,
host_key_check).
Signed-off-by: Max Reitz <mreitz@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Message-id: 20190225190828.17726-3-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This requires some changes to keep iotests 104 and 207 working.
qemu-img info in 104 will now return a filename including the user name
and the port, which need to be filtered by adjusting REMOTE_TEST_DIR in
common.rc. This additional information has to be marked optional,
however (which is simple as REMOTE_TEST_DIR is a regex), because
otherwise 197 and 215 would fail: They use it (indirectly) to filter
qemu-img create output which contains a backing filename they have
passed to it -- which probably does not contain a user name or port
number.
The problem in 207 is a nice one to have: qemu-img info used to return
json:{} filenames, but with this patch it returns nice plain ones. We
now need to adjust the filtering to hide the user name (and port number
while we are at it). The simplest way to do this is to include both in
iotests.remote_filename() so that bdrv_refresh_filename() will not
change it, and then iotests.img_info_log() will filter it correctly
automatically.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Message-id: 20190225190828.17726-2-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Bitmap data may take a lot of disk space, so it's better to discard it
always.
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Message-id: 1551346019-293202-1-git-send-email-andrey.shinkevich@virtuozzo.com
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
[mreitz: Use the commit message proposed by Vladimir]
Signed-off-by: Max Reitz <mreitz@redhat.com>
No reasons for not reporting found corruptions as corruptions in case
of some internal errors, especially in case of just failed to fix l2
entry (and in this case, missed corruptions may influence comparing
logic, when we calculate difference between corruptions fields of two
results)
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190227131433.197063-6-vsementsov@virtuozzo.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Do not count a cluster which is fixed to be ZERO as allocated.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190227131433.197063-5-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reduce number of structures ignored in overlap check: when checking
active table ignore active tables, when checking inactive table ignore
inactive ones.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190227131433.197063-4-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
qcow2_inc_refcounts_imrt() (through realloc_refcount_array()) can eat
an unpredictable amount of memory on corrupted table entries, which are
referencing regions far beyond the end of file.
Prevent this, by skipping such regions from further processing.
Interesting that iotest 138 checks exactly the behavior which we fix
here. So, change the test appropriately.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190227131433.197063-3-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Increase corruptions_fixed only after successful fix.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190227131433.197063-2-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
qed_read_table and qed_write_table use coroutine-only interfaces but
are not marked coroutine_fn. Happily, they are called only from
coroutine context, so we only need to add missed markers.
Reported-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
You can reproduce this by passing an invalid filter-node-name (like
"1234") to block-commit. In this case the base image is put in
read-write mode but is never reset back to read-only.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Move to _co_ versions of io functions qed_read_table() and
qed_write_table(), as we use qemu_co_mutex_unlock()
anyway.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch fixes a few things in the way error codes are handled in
the qcow2 compression code:
a) qcow2_co_pwritev_compressed() expects qcow2_co_compress() to only
return -1 or -2 on failure, but this is not correct. Since the
change from qcow2_compress() to qcow2_co_compress() in commit
ceb029cd6f the new code can also return -EINVAL (although
there does not seem to exist any code path that would cause that
error in the current implementation).
b) -1 and -2 are ad-hoc error codes defined in qcow2_compress().
This patch replaces them with standard constants from errno.h.
c) Both qcow2_compress() and qcow2_co_do_compress() return a negative
value on failure, but qcow2_co_pwritev_compressed() stores the
value in an unsigned data type.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
make_completely_empty() is an optimisated path for bdrv_make_empty()
where completely new metadata is created inside the image file instead
of going through all clusters and discarding them. For an external data
file, however, we actually need to do discard operations on the data
file; just overwriting the qcow2 file doesn't get rid of the data.
The necessary slow path with an explicit discard operation already
exists for other cases. Use it for external data files, too.
Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
preallocate_co() already gave the data file the full size without
forwarding the requested preallocation mode to the protocol. When
bdrv_co_truncate() was called later with the preallocation mode, the
file didn't actually grow any more, so the data file stayed unallocated
even if full preallocation was requested.
Pass the right preallocation mode to preallocate_co() and remove the
second bdrv_co_truncate() to fix this. As a side effect, the ugly
one-byte write in preallocate_co() is replaced with a truncate call,
now leaving the last block unallocated on the protocol level as it
should be.
Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
We'll add a bdrv_co_truncate() call in the next patch which can return
an Error that we don't want to discard. So add an errp parameter to
preallocate_co().
Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Limiting the allocation to INT_MAX bytes isn't particularly clever
because it means that the final cluster will be a partial cluster which
will be completed through a COW operation. This results in unnecessary
data read and write requests which lead to an unwanted non-sparse
filesystem block for metadata preallocation.
Align the maximum allocation size down to the cluster size to avoid this
situation.
Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Disk sizes close to INT64_MAX cause overflow, for some pretty
ridiculous output:
$ ./nbdkit -U - memory size=$((2**63 - 512)) --run 'qemu-img info $nbd'
image: nbd+unix://?socket=/tmp/nbdkitHSAzNz/socket
file format: raw
virtual size: -8388607T (9223372036854775296 bytes)
disk size: unavailable
But there's no reason to have two separate implementations of integer
to human-readable abbreviation, where one has overflow and stops at
'T', while the other avoids overflow and goes all the way to 'E'. With
this patch, the output now claims 8EiB instead of -8388607T, which
really is the correct rounding of largest file size supported by qemu
(we could go 511 bytes larger if we used byte-accurate sizing instead
of rounding up to the next sector boundary, but that wouldn't change
the human-readable result).
Quite a few iotests need updates to expected output to match.
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Tested-by: Max Reitz <mreitz@redhat.com>
Using IEC binary prefixes in order to make the code more readable,
with the exception of DEFAULT_LOG_SIZE because it's passed to
stringify().
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
IEC binary prefixes are already defined in "qemu/units.h",
so we can remove redundant definitions in "block/vhdx.h".
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Commit b69864e5a ("vmdk: Support version=3 in VMDK descriptor files")
fixed the probe function to correctly guess vmdk descriptors with
version=3.
This solves the issue where vmdk snapshot with parent vmdk descriptor
containing "version=3" would be treated as raw instead vmdk.
In the future case where a new vmdk version is introduced, we will again
experience this issue, even if the user will provide "-f vmdk" it will
only apply to the tip image and not to the underlying "misprobed" parent
image.
The code in vmdk.c already assumes that the backing file of vmdk must be
vmdk (see vmdk_is_cid_valid which returns 0 if backing file is not
vmdk).
So let's make it official by supplying the backing_format as vmdk.
Reviewed-by: Mark Kanda <mark.kanda@oracle.com>
Reviewed-By: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Arbel Moshe <arbel.moshe@oracle.com>
Signed-off-by: Shmuel Eiderman <shmuel.eiderman@oracle.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <fam@euphon.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Concurrent IO becomes serial IO because of the qemu Coroutine lock,
which reduce IO performance severely.
So unlock Coroutine lock before bdrv_co_pwritev and
bdrv_co_preadv to fix it.
Signed-off-by: Zhengui li <lizhengui@huawei.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
bdrv_snapshot_dump(), bdrv_image_info_specific_dump(),
bdrv_image_info_dump() and their helpers take an fprintf()-like
callback and a FILE * to pass to it.
hmp.c passes monitor_printf() cast to fprintf_function and the current
monitor cast to FILE *.
qemu-img.c and qemu-io-cmds.c pass fprintf and stdout.
The type-punning is technically undefined behaviour, but works in
practice. Clean up: drop the callback, and call qemu_printf()
instead.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20190417191805.28198-8-armbru@redhat.com>
Callbacks ssh_co_readv(), ssh_co_writev(), ssh_co_flush() report
errors to the user with error_printf(). They shouldn't, it's their
caller's job. Replace by a suitable trace point. While there, drop
the unreachable !s->sftp case.
Perhaps we should convert this part of the block driver interface to
Error, so block drivers can pass more detail to their callers. Not
today.
Cc: "Richard W.M. Jones" <rjones@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Max Reitz <mreitz@redhat.com>
Cc: qemu-block@nongnu.org
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190417190641.26814-3-armbru@redhat.com>
With an external data file, preallocate_co() must write the final byte
to the external data file, not to the qcow2 image file.
This is harmless for preallocation of newly created images (only the
qcow2 file size is increased to the virtual disk size while it should be
much smaller), but with preallocated resize, it could in theory cause
visible corruption if the metadata of the image is larger than the data
(e.g. lots of bitmaps).
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Commit 6585493369 added code to freeze
the backing chain from 'top' to 'base' for the duration of the
block-stream job.
The problem is that the freezing happens too late in stream_start():
during the bdrv_reopen_set_read_only() call earlier in that function
another job can jump in and remove the base image. If that happens we
have an invalid chain and QEMU crashes.
This patch puts the bdrv_freeze_backing_chain() call at the beginning
of the function.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
bdrv_replace_child() calls bdrv_check_perm() with error_abort on
loosening permissions. However file-locking operations may fail even
in this case, for example on NFS. And this leads to Qemu crash.
Let's avoid such errors. Note, that we ignore such things anyway on
permission update commit and abort.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Several versions of GlusterFS (3.12? -> 6.0.1) fail when the
transfer size is greater or equal to 1024 MiB, so we are
limiting the transfer size to 512 MiB to avoid this rare issue.
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1691320
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Just as we recently added a trace for a server sending block status
that doesn't match the server's advertised minimum block alignment,
let's do the same for read chunks. But since qemu 3.1 is such a
server (because it advertised 512-byte alignment, but when serving a
file that ends in data but is not sector-aligned, NBD_CMD_READ would
detect a mid-sector change between data and hole at EOF and the
resulting read chunks are unaligned), we don't want to change our
behavior of otherwise tolerating unaligned reads.
Note that even though we fixed the server for 4.0 to advertise an
actual block alignment (which gets rid of the unaligned reads at EOF
for posix files), we can still trigger it via other means:
$ qemu-nbd --image-opts driver=blkdebug,align=512,image.driver=file,image.filename=/path/to/non-aligned-file
Arguably, that is a bug in the blkdebug block status function, for
leaking a block status that is not aligned. It may also be possible to
observe issues with a backing layer with smaller alignment than the
active layer, although so far I have been unable to write a reliable
iotest for that scenario.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190330165349.32256-1-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
The next patch needs access to a device's minimum permitted
alignment, since NBD wants to advertise this to clients. Add
an accessor function, borrowing from blk_get_max_transfer()
for accessing a backend's block limits.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20190329042750.14704-6-eblake@redhat.com>
If an NBD server advertises a size that is not a multiple of a sector,
the block layer rounds up that size, even though we set info.size to
the exact byte value sent by the server. The block layer then proceeds
to let us read or query block status on the hole that it added past
EOF, which the NBD server is unlikely to be happy with. Fortunately,
qemu as a server never advertizes an unaligned size, so we generally
don't run into this problem; but the nbdkit server makes it easy to
test:
$ printf %1000d 1 > f1
$ ~/nbdkit/nbdkit -fv file f1 & pid=$!
$ qemu-img convert -f raw nbd://localhost:10809 f2
$ kill $pid
$ qemu-img compare f1 f2
Pre-patch, the server attempts a 1024-byte read, which nbdkit
rightfully rejects as going beyond its advertised 1000 byte size; the
conversion fails and the output files differ (not even the first
sector is copied, because qemu-img does not follow ddrescue's habit of
trying smaller reads to get as much information as possible in spite
of errors). Post-patch, the client's attempts to read (and query block
status, for new enough nbdkit) are properly truncated to the server's
length, with sane handling of the hole the block layer forced on
us. Although f2 ends up as a larger file (1024 bytes instead of 1000),
qemu-img compare shows the two images to have identical contents for
display to the guest.
I didn't add iotests coverage since I didn't want to add a dependency
on nbdkit in iotests. I also did NOT patch write, trim, or write
zeroes - these commands continue to fail (usually with ENOSPC, but
whatever the server chose), because we really can't write to the end
of the file, and because 'qemu-img convert' is the most common case
where we care about being tolerant (which is read-only). Perhaps we
could truncate the request if the client is writing zeros to the tail,
but that seems like more work, especially if the block layer is fixed
in 4.1 to track byte-accurate sizing (in which case this patch would
be reverted as unnecessary).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190329042750.14704-5-eblake@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
It is desirable for 'qemu-img map' to have the same output for a file
whether it is served over file or nbd protocols. However, ever since
we implemented block status for NBD (2.12), the NBD protocol forgot to
inform the block layer that as the final layer in the chain, the
offset is valid; without an offset, the human-readable form of
qemu-img map gives up with the unhelpful:
$ nbdkit -U - data data="1" size=512 --run 'qemu-img map $nbd'
Offset Length Mapped to File
qemu-img: File contains external, encrypted or compressed clusters.
The --output=json form always works, because it is reporting the
lower-level bdrv_block_status results directly rather than trying to
filter out sparse ranges for human consumption - but now it also
shows the offset member.
With this patch, the human output changes to:
Offset Length Mapped to File
0 0x200 0 nbd+unix://?socket=/tmp/nbdkitOxeoLa/socket
This change is observable to several iotests.
Fixes: 78a33ab5
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190329042750.14704-4-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
We have a latent bug in our NBD client code, tickled by the brand new
nbdkit 1.11.10 block status support:
$ nbdkit --filter=log --filter=truncate -U - \
data data="1" size=511 truncate=64K logfile=/dev/stdout \
--run 'qemu-img convert $nbd /var/tmp/out'
...
qemu-img: block/io.c:2122: bdrv_co_block_status: Assertion `*pnum && QEMU_IS_ALIGNED(*pnum, align) && align > offset - aligned_offset' failed.
The culprit? Our implementation of .bdrv_co_block_status can return
unaligned block status for any server that operates with a lower
actual alignment than what we tell the block layer in
request_alignment, in violation of the block layer's constraints. To
date, we've been unable to trip the bug, because qemu as NBD server
always advertises block sizing (at which point it is a server bug if
the server sends unaligned status - although qemu 3.1 is such a server
and I've sent separate patches for 4.0 both to get the server to obey
the spec, and to let the client to tolerate server oddities at EOF).
But nbdkit does not (yet) advertise block sizing, and therefore is not
in violation of the spec for returning block status at whatever
boundaries it wants, and those unaligned results can occur anywhere
rather than just at EOF. While we are still wise to avoid sending
sub-sector read/write requests to a server of unknown origin, we MUST
consider that a server telling us block status without an advertised
block size is correct. So, we either have to munge unaligned answers
from the server into aligned ones that we hand back to the block
layer, or we have to tell the block layer about a smaller alignment.
Similarly, if the server advertises an image size that is not
sector-aligned, we might as well assume that the server intends to let
us access those tail bytes, and therefore supports a minimum block
size of 1, regardless of whether the server supports block status
(although we still need more patches to fix the problem that with an
unaligned image, we can send read or block status requests that exceed
EOF to the server). Again, qemu as server cannot trip this problem
(because it rounds images to sector alignment), but nbdkit advertised
unaligned size even before it gained block status support.
Solve both alignment problems at once by using better heuristics on
what alignment to report to the block layer when the server did not
give us something to work with. Note that very few NBD servers
implement block status (to date, only qemu and nbdkit are known to do
so); and as the NBD spec mentioned block sizing constraints prior to
documenting block status, it can be assumed that any future
implementations of block status are aware that they must advertise
block size if they want a minimum size other than 1.
We've had a long history of struggles with picking the right alignment
to use in the block layer, as evidenced by the commit message of
fd8d372d (v2.12) that introduced the current choice of forced 512-byte
alignment.
There is no iotest coverage for this fix, because qemu can't provoke
it, and I didn't want to make test 241 dependent on nbdkit.
Fixes: fd8d372d
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190329042750.14704-3-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
The NBD spec is clear that a server that advertises a minimum block
size should reply to NBD_CMD_BLOCK_STATUS with extents aligned
accordingly. However, we know that the qemu NBD server implementation
has had a corner-case bug where it is not compliant with the spec,
present since the introduction of NBD_CMD_BLOCK_STATUS in qemu 2.12
(and unlikely to be patched in time for 4.0). Namely, when qemu is
serving a file that is not a multiple of 512 bytes, it rounds the size
advertised over NBD up to the next sector boundary (someday, I'd like
to fix that to be byte-accurate, but it's a much bigger audit not
appropriate for this release); yet if the final sector contains data
prior to EOF, lseek(SEEK_HOLE) will point to the implicit hole
mid-sector which qemu then reported over NBD.
We are well within our rights to hang up on a server that can't follow
the spec, but it is more useful to try and keep the connection alive
in spite of the problem. Do so by tracing a message about the problem,
and then either truncating the request back to an aligned boundary (if
it covered more than the final sector) or widening it out to the full
boundary with a forced status of data (since truncating would result
in 0 bytes, but we have to make progress, and valid since data is a
default-safe answer). And in practice, since the problem only happens
on a sector that starts with data and ends with a hole, we are going
to want to read that full sector anyway (where qemu as the server
fills in the tail beyond EOF with appropriate NUL bytes).
Easy reproduction:
$ printf %1000d 1 > file
$ qemu-nbd -f raw -t file & pid=$!
$ qemu-img map --output=json -f raw nbd://localhost:10809
qemu-img: Could not read file metadata: Invalid argument
$ kill $pid
where the patched version instead succeeds with:
[{ "start": 0, "length": 1024, "depth": 0, "zero": false, "data": true}]
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190326171317.4036-1-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
The NBD spec is clear that when structured replies are active, a
simple error reply is acceptable to any command except for
NBD_CMD_READ. However, we were mistakenly requiring structured errors
for NBD_CMD_BLOCK_STATUS, and hanging up on a server that gave a
simple error (since qemu does not behave as such a server, we didn't
notice the problem until now). Broken since its introduction in
commit 78a33ab5 (v2.12).
Noticed while debugging a separate failure reported by nbdkit while
working out its initial implementation of BLOCK_STATUS, although it
turns out that nbdkit also chose to send structured error replies for
BLOCK_STATUS, so I had to manually provoke the situation by hacking
qemu's server to send a simple error reply:
| diff --git i/nbd/server.c w/nbd/server.c
| index fd013a2817a..833288d7c45 100644
| 00--- i/nbd/server.c
| +++ w/nbd/server.c
| @@ -2269,6 +2269,8 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
| "discard failed", errp);
|
| case NBD_CMD_BLOCK_STATUS:
| + return nbd_co_send_simple_reply(client, request->handle, ENOMEM,
| + NULL, 0, errp);
| if (!request->len) {
| return nbd_send_generic_reply(client, request->handle, -EINVAL,
| "need non-zero length", errp);
|
Signed-off-by: Eric Blake <eblake@redhat.com>
Acked-by: Richard W.M. Jones <rjones@redhat.com>
Message-Id: <20190325190104.30213-3-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
When the server replies with a (structured [*]) error to
NBD_CMD_BLOCK_STATUS, without any extent information sent first, the
client code was blindly throwing away the server's error code and
instead telling the caller that EIO occurred. This has been broken
since its introduction in 78a33ab5 (v2.12, where we should have called:
error_setg(&local_err, "Server did not reply with any status extents");
nbd_iter_error(&iter, false, -EIO, &local_err);
to declare the situation as a non-fatal error if no earlier error had
already been flagged, rather than just blindly slamming iter.err and
iter.ret), although it is more noticeable since commit 7f86068d, which
actually tries hard to preserve the server's code thanks to a separate
iter.request_ret.
[*] The spec is clear that the server is also permitted to reply with
a simple error, but that's a separate fix.
I was able to provoke this scenario with a hack to the server, then
seeing whether ENOMEM makes it back to the caller:
| diff --git a/nbd/server.c b/nbd/server.c
| index fd013a2817a..29c7995de02 100644
| --- a/nbd/server.c
| +++ b/nbd/server.c
| @@ -2269,6 +2269,8 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
| "discard failed", errp);
|
| case NBD_CMD_BLOCK_STATUS:
| + return nbd_send_generic_reply(client, request->handle, -ENOMEM,
| + "no status for you today", errp);
| if (!request->len) {
| return nbd_send_generic_reply(client, request->handle, -EINVAL,
| "need non-zero length", errp);
| --
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190325190104.30213-2-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
The NBD spec states that NBD_CMD_FLAG_REQ_ONE (which we currently
always use) should not reply with an extent larger than our request,
and that the server's response should be exactly one extent. Right
now, that means that if a server sends more than one extent, we treat
the server as broken, fail the block status request, and disconnect,
which prevents all further use of the block device. But while good
software should be strict in what it sends, it should be tolerant in
what it receives.
While trying to implement NBD_CMD_BLOCK_STATUS in nbdkit, we
temporarily had a non-compliant server sending too many extents in
spite of REQ_ONE. Oddly enough, 'qemu-img convert' with qemu 3.1
failed with a somewhat useful message:
qemu-img: Protocol error: invalid payload for NBD_REPLY_TYPE_BLOCK_STATUS
which then disappeared with commit d8b4bad8, on the grounds that an
error message flagged only at the time of coroutine teardown is
pointless, and instead we should rely on the actual failed API to
report an error - in other words, the 3.1 behavior was masking the
fact that qemu-img was not reporting an error. That has since been
fixed in the previous patch, where qemu-img convert now fails with:
qemu-img: error while reading block status of sector 0: Invalid argument
But even that is harsh. Since we already partially relaxed things in
commit acfd8f7a to tolerate a server that exceeds the cap (although
that change was made prior to the NBD spec actually putting a cap on
the extent length during REQ_ONE - in fact, the NBD spec change was
BECAUSE of the qemu behavior prior to that commit), it's not that much
harder to argue that we should also tolerate a server that sends too
many extents. But at the same time, it's nice to trace when we are
being tolerant of server non-compliance, in order to help server
writers fix their implementations to be more portable (if they refer
to our traces, rather than just stderr).
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190323212639.579-3-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
We know that the kernel implements a slow fallback code path for
BLKZEROOUT, so if BDRV_REQ_NO_FALLBACK is given, we shouldn't call it.
The other operations we call in the context of .bdrv_co_pwrite_zeroes
should usually be quick, so no modification should be needed for them.
If we ever notice that there are additional problematic cases, we can
still make these conditional as well.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
Filter drivers that support .bdrv_co_pwrite_zeroes can safely advertise
BDRV_REQ_NO_FALLBACK because they just forward the request flags to
their child node.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
For qemu-img convert, we want an operation that zeroes out the whole
image if this can be done efficiently, but that returns an error
otherwise so we don't write explicit zeroes and immediately overwrite
them with the real data, potentially doubling the amount of data to be
written.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
There is only a single caller of bdrv_make_zero(), which is qemu-img
convert. If the function fails, we just fall back to a different method
of zeroing out blocks on the target image. There is no good reason to
print error messages on stderr when the higher level operation will
actually succeed.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
Tracked down with cleanup-trace-events.pl. Funnies requiring manual
post-processing:
* block.c and blockdev.c trace points are in block/trace-events.
* hw/block/nvme.c uses the preprocessor to hide its trace point use
from cleanup-trace-events.pl.
* include/hw/xen/xen_common.h trace points are in hw/xen/trace-events.
* net/colo-compare and net/filter-rewriter.c use pseudo trace points
colo_compare_udp_miscompare and colo_filter_rewriter_debug to guard
debug code.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-id: 20190314180929.27722-5-armbru@redhat.com
Message-Id: <20190314180929.27722-5-armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
We spell out sub/dir/ in sub/dir/trace-events' comments pointing to
source files. That's because when trace-events got split up, the
comments were moved verbatim.
Delete the sub/dir/ part from these comments. Gets rid of several
misspellings.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190314180929.27722-3-armbru@redhat.com
Message-Id: <20190314180929.27722-3-armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Commit 509d39aa22 added support for read
only VMDKs of version 3.
This commit fixes the probe function to correctly handle descriptors of
version 3.
This commit has two effects:
1. We no longer need to supply '-f vmdk' when pointing to descriptor
files of version 3 in qemu/qemu-img command line arguments.
2. This fixes the scenario where a VMDK points to a parent version 3
descriptor file which is being probed as "raw" instead of "vmdk".
Reviewed-by: Arbel Moshe <arbel.moshe@oracle.com>
Reviewed-by: Mark Kanda <mark.kanda@oracle.com>
Signed-off-by: Shmuel Eiderman <shmuel.eiderman@oracle.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We were trying to check whether bdrv_open_blockdev_ref() returned
success, but accidentally checked the wrong variable. Spotted by
Coverity (CID 1399703).
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
While child_job_drained_begin() calls to job_pause(), the job doesn't
actually transition between states until it runs again and reaches a
pause point. This means bdrv_drained_begin() may return with some jobs
using the node still having 'busy == true'.
As a consequence, block_job_detach_aio_context() may get into a
deadlock, waiting for the job to be actually paused, while the coroutine
servicing the job is yielding and doesn't get the opportunity to get
scheduled again. This situation can be reproduced by issuing a
'block-commit' immediately followed by a 'device_del'.
To ensure bdrv_drained_begin() only returns when the jobs have been
paused, we change mirror_drained_poll() to only confirm it's quiesced
when job->paused == true and there aren't any in-flight requests, except
if we reached that point by a drained section initiated by the
mirror/commit job itself.
The other block jobs shouldn't need any changes, as the default
drained_poll() behavior is to only confirm it's quiesced if the job is
not busy or completed.
Signed-off-by: Sergio Lopez <slp@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* Add 'drop-cache=on|off' option to file-posix.c. The default is on.
Disabling the option fixes a QEMU 3.0.0 performance regression when live
migrating on the same host with cache.direct=off.
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Merge remote-tracking branch 'remotes/stefanha/tags/block-pull-request' into staging
Pull request
* Add 'drop-cache=on|off' option to file-posix.c. The default is on.
Disabling the option fixes a QEMU 3.0.0 performance regression when live
migrating on the same host with cache.direct=off.
# gpg: Signature made Wed 13 Mar 2019 11:07:48 GMT
# gpg: using RSA key 9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" [full]
# gpg: aka "Stefan Hajnoczi <stefanha@gmail.com>" [full]
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35 775A 9CA4 ABB3 81AB 73C8
* remotes/stefanha/tags/block-pull-request:
file-posix: add drop-cache=on|off option
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Commit dd577a26ff ("block/file-posix:
implement bdrv_co_invalidate_cache() on Linux") introduced page cache
invalidation so that cache.direct=off live migration is safe on Linux.
The invalidation takes a significant amount of time when the file is
large and present in the page cache. Normally this is not the case for
cross-host live migration but it can happen when migrating between QEMU
processes on the same host.
On same-host migration we don't need to invalidate pages for correctness
anyway, so an option to skip page cache invalidation is useful. I
investigated optimizing invalidation and detecting same-host migration,
but both are hard to achieve so a user-visible option will suffice.
As a bonus this option means that the cache invalidation feature will
now be detectable by libvirt via QMP schema introspection.
Suggested-by: Neil Skrypuch <neil@tembosocial.com>
Tested-by: Neil Skrypuch <neil@tembosocial.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190307164941.3322-1-stefanha@redhat.com
Message-Id: <20190307164941.3322-1-stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
If we reopen a BlockDriverState and there is an option that is present
in bs->options but missing from the new set of options then we have to
return an error unless the driver is able to reset it to its default
value.
This patch adds a new 'mutable_opts' field to BlockDriver. This is
a list of runtime options that can be modified during reopen. If an
option in this list is unspecified on reopen then it must be reset (or
return an error).
Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The bdrv_reopen_queue() function is used to create a queue with
the BDSs that are going to be reopened and their new options. Once
the queue is ready bdrv_reopen_multiple() is called to perform the
operation.
The original options from each one of the BDSs are kept, with the new
options passed to bdrv_reopen_queue() applied on top of them.
For "x-blockdev-reopen" we want a function that behaves much like
"blockdev-add". We want to ignore the previous set of options so that
only the ones actually specified by the user are applied, with the
rest having their default values.
One of the things that we need is a way to tell bdrv_reopen_queue()
whether we want to keep the old set of options or not, and that's what
this patch does. All current callers are setting this new parameter to
true and x-blockdev-reopen will set it to false.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Until now, with auto-read-only=on we tried to open the file read-write
first and if that failed, read-only was tried. This is actually not good
enough for libvirt, which gives QEMU SELinux permissions for read-write
only as soon as it actually intends to write to the image. So we need to
be able to switch between read-only and read-write at runtime.
This patch makes auto-read-only dynamic, i.e. the file is opened
read-only as long as no user of the node has requested write
permissions, but it is automatically reopened read-write as soon as the
first writer is attached. Conversely, if the last writer goes away, the
file is reopened read-only again.
bs->read_only is no longer set for auto-read-only=on files even if the
file descriptor is opened read-only because it will be transparently
upgraded as soon as a writer is attached. This changes the output of
qemu-iotests 232.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
In order to be able to dynamically reopen the file read-only or
read-write, depending on the users that are attached, we need to be able
to switch to a different file descriptor during the permission change.
This interacts with reopen, which also creates a new file descriptor and
performs permission changes internally. In this case, the permission
change code must reuse the reopen file descriptor instead of creating a
third one.
In turn, reopen can drop its code to copy file locks to the new file
descriptor because that is now done when applying the new permissions.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
There is no reason why we can take locks on the new file descriptor only
in raw_reopen_commit() where error handling isn't possible any more.
Instead, we can already do this in raw_reopen_prepare().
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
We'll want to access the file descriptor in the reopen_state while
processing permission changes in the context of the repoen.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Drop x- and x_ prefixes for latency histograms and update version to
4.0
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Since we now load all bitmaps into memory anyway, we can just truncate
them in-memory and then flush them back to disk. Just in case, we will
still check and enforce that this shortcut is valid -- i.e. that any
bitmap described on-disk is indeed in-memory and can be modified.
If there are any inconsistent bitmaps, we refuse to allow the truncate
as we do not actually load these bitmaps into memory, and it isn't safe
or reasonable to attempt to truncate corrupted data.
Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190311185147.52309-4-vsementsov@virtuozzo.com
[vsementsov: drop bitmap flushing, fix block comments style]
Signed-off-by: John Snow <jsnow@redhat.com>
We are going to allow image resize when there are persistent bitmaps.
It may lead to appearing of inconsistent bitmaps (IN_USE=1) with
inconsistent size. But we still want to load them as inconsistent.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190311185147.52309-3-vsementsov@virtuozzo.com
Signed-off-by: John Snow <jsnow@redhat.com>
Commit a88b179f introduced the ability to set and query bitmap
persistence, but with an atypical spelling.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-id: 20190308205845.25734-1-eblake@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
Set the inconsistent bit on load instead of rejecting such bitmaps.
There is no way to un-set it; the only option is to delete the bitmap.
Obvervations:
- bitmap loading does not need to update the header for in_use bitmaps.
- inconsistent bitmaps don't need to have their data loaded; they're
glorified corruption sentinels.
- bitmap saving does not need to save inconsistent bitmaps back to disk.
- bitmap reopening DOES need to drop the readonly flag from inconsistent
bitmaps to allow reopening of qcow2 files with non-qemu-owned bitmaps
being eventually flushed back to disk.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20190301191545.8728-8-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
We didn't do any state checking on source bitmaps at all,
so this adds inconsistent and busy checks. readonly is
allowed, so you can still copy a readonly bitmap to a new
destination to use it for operations like drive-backup.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190301191545.8728-7-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
Instead of checking against busy, inconsistent, or read only directly,
use a check function with permissions bits that let us streamline the
checks without reproducing them in many places.
Included in this patch are permissions changes that simply add the
inconsistent check to existing permissions call spots, without
addressing existing bugs.
In general, this means that busy+readonly checks become BDRV_BITMAP_DEFAULT,
which checks against all three conditions. busy-only checks become
BDRV_BITMAP_ALLOW_RO.
Notably, remove allows inconsistent bitmaps, so it doesn't follow the pattern.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190301191545.8728-4-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
Even though the status field is deprecated, we still have to support
it for a few more releases. Since this is a very new kind of bitmap
state, it makes sense for it to have its own status field.
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190301191545.8728-3-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
Add an inconsistent bit to dirty-bitmaps that allows us to report a bitmap as
persistent but potentially inconsistent, i.e. if we find bitmaps on a qcow2
that have been marked as "in use".
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190301191545.8728-2-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
Simply move the big status enum comment block to above the status
function, and document it as being deprecated. The whole confusing
block can get deleted in three releases time.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190223000614.13894-9-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
These mean the same thing now. Unify them and rename the merged call
bdrv_dirty_bitmap_busy to indicate semantically what we are describing,
as well as help disambiguate from the various _locked and _unlocked
versions of bitmap helpers that refer to mutex locks.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190223000614.13894-8-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
Instead of implying a user_locked/busy status, make it explicit.
Now, bitmaps in use by migration, NBD or backup operations
are all treated the same way with the same code paths.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190223000614.13894-7-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
Currently, the enabled predicate means something like:
"the QAPI status of the bitmap is ACTIVE."
After this patch, it should mean exclusively:
"This bitmap is recording guest writes, and is allowed to do so."
In many places, this is how this predicate was already used.
Internal usages of the bitmap QPI can call user_locked to find out if
the bitmap is in use by an operation.
To accommodate this, modify the create_successor routine to now
explicitly disable the parent bitmap at creation time.
Justifications:
1. bdrv_dirty_bitmap_status suffers no change from the lack of
1:1 parity with the new predicates because of the order in which
the predicates are checked. This is now only for compatibility.
2. bdrv_set_dirty() is unchanged: pre-patch, it was skipping bitmaps that were
disabled or had a successor, while post-patch it is only skipping bitmaps
that are disabled. To accommodate this, create_successor now ensures that
any bitmap with a successor is explicitly disabled.
3. qcow2_store_persistent_dirty_bitmaps: No functional change. This function
cares only about the literal enabled bit, and makes no effort to check if
the bitmap is in-use or not. After this patch there are still no ways to
produce an enabled bitmap with a successor.
4. block_dirty_bitmap_enable_prepare
block_dirty_bitmap_disable_prepare
init_dirty_bitmap_migration
nbd_export_new
These functions care about the literal enabled bit,
and already check user_locked separately.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190223000614.13894-5-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
bdrv_set_dirty_bitmap and bdrv_reset_dirty_bitmap are only used as an
internal API by the mirror and migration areas of our code. These
calls modify the bitmap, but do so at the behest of QEMU and not the
guest.
Presently, these bitmaps are always "enabled" anyway, but there's no
reason they have to be.
Modify these internal APIs to drop this assertion.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190223000614.13894-4-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
"Frozen" was a good description a long time ago, but it isn't adequate now.
Rename the frozen predicate to has_successor to make the semantics of the
predicate more clear to outside callers.
In the process, remove some calls to frozen() that no longer semantically
make sense. For bdrv_enable_dirty_bitmap_locked and
bdrv_disable_dirty_bitmap_locked, it doesn't make sense to prohibit QEMU
internals from performing this action when we only wished to prohibit QMP
users from issuing these commands. All of the QMP API commands for bitmap
manipulation already check against user_locked() to prohibit these actions.
Several other assertions really want to check that the bitmap isn't in-use
by another operation -- use the bitmap_user_locked function for this instead,
which presently also checks for has_successor. This leaves some redundant
checks of has_successor through different helpers that are addressed in
forthcoming patches.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190223000614.13894-3-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
The current API allows us to report a single status, which we've defined as:
Frozen: has a successor, treated as qmp_locked, may or may not be enabled.
Locked: no successor, qmp_locked. may or may not be enabled.
Disabled: Not frozen or locked, disabled.
Active: Not frozen, locked, or disabled.
The problem is that both "Frozen" and "Locked" mean nearly the same thing,
and that both of them do not intuit whether they are recording guest writes
or not.
This patch deprecates that status field and introduces two orthogonal
properties instead to replace it.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190223000614.13894-2-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
The glfs_*_async() functions do a callback once finished. This callback
has changed its arguments, pre- and post-stat structures have been
added. This makes it possible to improve caching, which is useful for
Samba and NFS-Ganesha, but not so much for QEMU. Gluster 6 is the first
release that includes these new arguments.
With an additional detection in ./configure, the new arguments can
conditionally get included in the glfs_io_cbk handler.
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
New versions of Glusters libgfapi.so have an updated glfs_ftruncate()
function that returns additional 'struct stat' structures to enable
advanced caching of attributes. This is useful for file servers, not so
much for QEMU. Nevertheless, the API has changed and needs to be
adopted.
Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Some Linux specific code is missing guards, leading to
build failure on OSX:
$ sudo brew install libiscsi
$ ./configure && make
[...]
CC block/iscsi.o
qemu/block/iscsi.c:338:24: error: 'iscsi_aiocb_info' defined but not used [-Werror=unused-const-variable=]
static const AIOCBInfo iscsi_aiocb_info = {
^~~~~~~~~~~~~~~~
qemu/block/iscsi.c:168:1: error: 'iscsi_schedule_bh' defined but not used [-Werror=unused-function]
iscsi_schedule_bh(IscsiAIOCB *acb)
^~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
Add guards to restrict this code for Linux.
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20190220000553.28438-1-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Provide an option to force QEMU to always keep the external data file
consistent as a standalone read-only raw image.
At the moment, this means making sure that write_zeroes requests are
forwarded to the data file instead of just updating the metadata, and
checking that no backing file is used.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
