Reading from qcow2 images is now byte granularity.

Most of the affected code in qcow2 actually gets simpler with this
change. The only exception is encryption, which is fixed on 512 bytes
blocks; in order to keep this working, bs->request_alignment is set for
encrypted images.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

This patch changes the units that qcow2_get_cluster_offset() uses
internally, without touching the interface just yet. This will be done
in another patch.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Drivers that implement .bdrv_co_pwritev() get the flags passed as an
argument to said function, but we also unconditionally emulate the flags
anyway. We shouldn't do that.

Fix this by clearing all flags that the driver supports natively after
it returns from .bdrv_co_pwritev().

Fixes: 4df863f3 ('block: Make supported_write_flags a per-bds property')
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

The code to exit the loop after bdrv_snapshot_delete_by_id_or_name()
returned failure was duplicated. The first copy of it was too early so
that the AioContext lock would not be freed. This patch removes it so
that only the second, correct copy remains.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>

The problem with excessive flushing was found by a couple of performance
tests:
  - parallel directory tree creation (from 2 processes)
  - 32 cached writes + fsync at the end in a loop

For the first one results improved from 2.6 loops/sec to 3.5 loops/sec.
Each loop creates 10^3 directories with 10 files in each.

For the second one results improved from ~600 fsync/sec to ~1100
fsync/sec. Though, it was run on SSD so it probably won't show such
performance gain on rotational media.

qcow2_cache_flush() calls bdrv_flush() unconditionally after writing
cache entries of a particular cache. This can lead to as many as
2 additional fdatasyncs inside bdrv_flush.

We can simply skip all fdatasync calls inside qcow2_co_flush_to_os
as bdrv_flush for sure will do the job. These flushes are necessary to
keep the right order of writes to the different caches. Though this is
not necessary in the current code base as this ordering is ensured through
the flush in qcow2_cache_flush_dependency().
Signed-off-by: NDenis V. Lunev <den@openvz.org>
CC: Pavel Borzenkov <pborzenkov@virtuozzo.com>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Max Reitz <mreitz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This is sometimes a useful value we should count in.
Signed-off-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Now that all drivers have been converted to a byte interface,
we no longer need a sector interface.
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Another step on our continuing quest to switch to byte-based
interfaces.
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Another step on our continuing quest to switch to byte-based
interfaces.
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Another step on our continuing quest to switch to byte-based
interfaces.
Signed-off-by: NEric Blake <eblake@redhat.com>
[ kwolf: Fixed up trace_paio_submit_co() call for qiov == NULL ]
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Another step on our continuing quest to switch to byte-based
interfaces.

Kill an abuse of the comma operator while at it (fortunately,
the semantics were still right).  Also, the test for requests
not aligned to clusters should be applied always, not just
when a backing file is present.
Signed-off-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Another step on our continuing quest to switch to byte-based
interfaces.
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Another step on our continuing quest to switch to byte-based
interfaces.
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Another step on our continuing quest to switch to byte-based
interfaces.
Signed-off-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Another step on our continuing quest to switch to byte-based
interfaces.

As this is the first byte-based iscsi interface, convert
is_request_lun_aligned() into two versions, one for sectors
and one for bytes.  Also, change from outright -EINVAL failure
on an unaligned request, to instead failing with -ENOTSUP to
trigger a read-modify-write fallback, particularly since the
block layer should be honoring bs->request_alignment to avoid
-EINVAL on read/write requests.
Signed-off-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Rename to bdrv_pwrite_zeroes() to let the compiler ensure we
cater to the updated semantics.  Do the same for bdrv_co_write_zeroes().
Signed-off-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Update bdrv_co_do_write_zeroes() to be byte-based, and select
between the new byte-based bdrv_co_pwrite_zeroes() or the old
bdrv_co_write_zeroes().  The next patches will convert drivers,
then remove the old interface.
Signed-off-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Another step towards removing sector-based interfaces: convert
the maximum write and minimum alignment values from sectors to
bytes.  Rename the variables to let the compiler check that all
users are converted to the new semantics.

The maximum remains an int as long as BDRV_REQUEST_MAX_SECTORS
is constrained by INT_MAX (this means that we can't even
support a 2G write_zeroes, but just under it) - changing
operation lengths to unsigned or to 64-bits is a much bigger
audit, and debatable if we even want to do it (since at the
core, a 32-bit platform will still have ssize_t as its
underlying limit on write()).

Meanwhile, alignment is changed to 'uint32_t', since it makes no
sense to have an alignment larger than the maximum write, and
less painful to use an unsigned type with well-defined behavior
in bit operations than to have to worry about what happens if
a driver mistakenly supplies a negative alignment.

Add an assert that no one was trying to use sectors to get a
write zeroes larger than 2G, and therefore that a later conversion
to bytes won't be impacted by keeping the limit at 32 bits.
Signed-off-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

If hardware does not advertise a minimum zero/discard
alignment, we still want to guarantee that the block layer
will align requests to our blocks, rather than the arbitrary
512-byte BDRV sector size.
Signed-off-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

is_zero_cluster() and is_zero_cluster_top_locked() are used only
by qcow2_co_write_zeroes().  The former is too broad (we don't
care if the sectors we are about to overwrite are non-zero, only
that all other sectors in the cluster are zero), so it needs to
be called up to twice but with smaller limits - rename it along
with adding the neeeded parameter.  The latter can be inlined for
more compact code.

The testsuite change shows that we now have a sparser top file
when an unaligned write_zeroes overwrites the only portion of
the backing file with data.

Based on a patch proposal by Denis V. Lunev.

CC: Denis V. Lunev <den@openvz.org>
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NDenis V. Lunev <den@openvz.org>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This patch follows guidelines of all other tracepoints in qcow2, like ones
in qcow2_co_writev. I think that they should dump values in the same
quantities or be changed all together.
Signed-off-by: NDenis V. Lunev <den@openvz.org>
CC: Eric Blake <eblake@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
Message-Id: <1463476543-3087-4-git-send-email-den@openvz.org>
[eblake: typo fix in commit message]
Signed-off-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Unaligned requests will occupy only one cluster. This is true since the
previous commit. Simplify the code taking this consideration into
account.

In other words, the caller is now buggy if it ever passes us an unaligned
request that crosses cluster boundaries (the only requests that can cross
boundaries will be aligned).

There are no other changes so far.
Signed-off-by: NDenis V. Lunev <den@openvz.org>
Reviewed-by: NEric Blake <eblake@redhat.com>
CC: Eric Blake <eblake@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
Message-Id: <1463476543-3087-3-git-send-email-den@openvz.org>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

We should split requests even if they are less than write_zeroes_alignment.
For example we can have the following request:
  offset 62k
  size   4k
  write_zeroes_alignment 64k
The original code sent 1 request covering 2 qcow2 clusters, and resulted
in both clusters being allocated. But by splitting the request, we can
cater to the case where one of the two clusters can be zeroed as a
whole, for only 1 cluster allocated after the operation.
Signed-off-by: NDenis V. Lunev <den@openvz.org>
CC: Eric Blake <eblake@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
Message-Id: <1463476543-3087-2-git-send-email-den@openvz.org>

[eblake: Avoid exceeding nb_sectors, hoist alignment checks out of
loop, and update testsuite to show that patch works]
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Replace (((n) + (d) - 1) /(d)) by DIV_ROUND_UP(n,d).

This patch is the result of coccinelle script
scripts/coccinelle/round.cocci

CC: qemu-block@nongnu.org
Signed-off-by: NLaurent Vivier <lvivier@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

Replace (((n) + (d) - 1) /(d)) by DIV_ROUND_UP(n,d).

This patch is the result of coccinelle script
scripts/coccinelle/round.cocci

CC: qemu-block@nongnu.org
Signed-off-by: NLaurent Vivier <lvivier@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

Replace (((n) + (d) - 1) /(d)) by DIV_ROUND_UP(n,d).

This patch is the result of coccinelle script
scripts/coccinelle/round.cocci

CC: qemu-block@nongnu.org
Signed-off-by: NLaurent Vivier <lvivier@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

Replace (((n) + (d) - 1) /(d)) by DIV_ROUND_UP(n,d).

This patch is the result of coccinelle script
scripts/coccinelle/round.cocci

CC: qemu-block@nongnu.org
Signed-off-by: NLaurent Vivier <lvivier@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

Remove glib.h includes, as it is provided by osdep.h.

This commit was created with scripts/clean-includes.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NEric Blake <eblake@redhat.com>
Tested-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

Similar to the "!drv || !drv->bdrv_aio_ioctl" case above, here it is
okay to set co.ret and return. As pointed out by Paolo, a BH will be
created as necessary by the caller (bdrv_co_maybe_schedule_bh).
Besides, as pointed out by Kevin, "data" was leaked before.
Reported-by: NKevin Wolf <kwolf@redhat.com>
Reported-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-id: 20160601015223.19277-1-famz@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

I was thrown by the fact that the public type BlockRequest had
an anonymous union, but no obvious discriminator.  Turns out
that the only client of the second branch of the union was code
internal to io.c, now that commit 91c6e4b7 killed public
multiwrite, so move it into io.c and improve the comments.
Signed-off-by: NEric Blake <eblake@redhat.com>
Message-Id: <1463699150-19445-1-git-send-email-eblake@redhat.com>
Signed-off-by: NFam Zheng <famz@redhat.com>

in a read-modify-write cycle a small request might cause
head and tail to fall into the same aligned block. Currently
QEMU reads the same block twice in this case which is
not necessary.
Signed-off-by: NPeter Lieven <pl@kamp.de>
Message-id: 1464607873-28206-1-git-send-email-pl@kamp.de
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Message-id: 1464599852-15392-1-git-send-email-kwolf@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

at least in the path via virtio-blk the maximum size is not
restricted.

Cc: qemu-stable@nongnu.org
Signed-off-by: NPeter Lieven <pl@kamp.de>
Message-Id: <1464080368-29584-1-git-send-email-pl@kamp.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This changes the commit block job to use the job's BlockBackend for
performing its I/O. job->bs isn't used by the commit code any more
afterwards.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

This changes the backup block job to use the job's BlockBackend for
performing its I/O. job->bs isn't used by the backup code any more
afterwards.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

Now that we pass the job to the function, bs is implied by that.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NAlberto Garcia <berto@igalia.com>

Instead of relying on peeking at bs->job, we want to explicitly get
a reference to the job that was involved in this notifier callback.

Pack the Notifier inside of the BackupBlockJob so we can use
container_of to get a reference back to the BackupBlockJob object.

This cuts out one more case where we rely unnecessarily on bs->job.
Suggested-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJohn Snow <jsnow@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NAlberto Garcia <berto@igalia.com>

This changes the mirror block job to use the job's BlockBackend for
performing its I/O. job->bs isn't used by the mirroring code any more
afterwards.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>

We had to forbid mirroring to a target BDS that already had a BB
attached because the node swapping at job completion would add a second
BB and we didn't support multiple BBs on a single BDS at the time. Now
we do, so we can lift the restriction.

As we allow additional BlockBackends for the target, we must expect
other users to be sending requests. There may no requests be in flight
during the graph modification, so we have to drain those users now.

The core part of this patch is a revert of commit 40365552.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>