Commit Graph

507 Commits

Author SHA1 Message Date
Markus Armbruster 6b67395762 Eliminate qapi/qmp/types.h
qapi/qmp/types.h is a convenience header to include a number of
qapi/qmp/ headers.  Since we rarely need all of the headers
qapi/qmp/types.h includes, we bypass it most of the time.  Most of the
places that use it don't need all the headers, either.

Include the necessary headers directly, and drop qapi/qmp/types.h.

Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180201111846.21846-9-armbru@redhat.com>
2018-02-09 13:52:15 +01:00
Markus Armbruster e688df6bc4 Include qapi/error.h exactly where needed
This cleanup makes the number of objects depending on qapi/error.h
drop from 1910 (out of 4743) to 1612 in my "build everything" tree.

While there, separate #include from file comment with a blank line,
and drop a useless comment on why qemu/osdep.h is included first.

Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180201111846.21846-5-armbru@redhat.com>
[Semantic conflict with commit 34e304e975 resolved, OSX breakage fixed]
2018-02-09 13:50:17 +01:00
Max Reitz c9ceb3ec8a qcow2: No persistent dirty bitmaps for compat=0.10
Persistent dirty bitmaps require a properly functioning
autoclear_features field, or we cannot track when an unsupporting
program might overwrite them.  Therefore, we cannot support them for
compat=0.10 images.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20171123020832.8165-3-mreitz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-01-23 12:34:42 +01:00
Edgar Kaziakhmedov 546a7dc40e qcow2: get rid of qcow2_backing_read1 routine
Since bdrv_co_preadv does all neccessary checks including
reading after the end of the backing file, avoid duplication
of verification before bdrv_co_preadv call.

Signed-off-by: Edgar Kaziakhmedov <edgar.kaziakhmedov@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-12-22 15:03:41 +01:00
Max Reitz 791fff504c qcow2: check_errors are fatal
When trying to repair a dirty image, qcow2_check() may apparently
succeed (no really fatal error occurred that would prevent the check
from continuing), but if check_errors in the result object is non-zero,
we cannot trust the image to be usable.

Reported-by: R. Nageswara Sastry <nasastry@in.ibm.com>
Buglink: https://bugs.launchpad.net/qemu/+bug/1728639
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20171110203111.7666-2-mreitz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-11-17 18:21:30 +01:00
Anton Nefedov 3e3b838ffe qcow2: reject unaligned offsets in write compressed
Misaligned compressed write is not supported.

Signed-off-by: Anton Nefedov <anton.nefedov@virtuozzo.com>
Message-id: 1510654613-47868-2-git-send-email-anton.nefedov@virtuozzo.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-11-17 18:21:30 +01:00
Eric Blake 4096974e18 qcow2: fix image corruption on commit with persistent bitmap
If an image contains persistent bitmaps, we cannot use the
fast path of bdrv_make_empty() to clear the image during
qemu-img commit, because that will lose the clusters related
to the bitmaps.

Also leave a comment in qcow2_read_extensions to remind future
feature additions to think about fast-path removal, since we
just barely fixed the same bug for LUKS encryption.

It's a pain that qemu-img has not yet been taught to manipulate,
or even at a very minimum display, information about persistent
bitmaps; instead, we have to use QMP commands.  It's also a
pain that only qeury-block and x-debug-block-dirty-bitmap-sha256
will allow bitmap introspection; but the former requires the
node to be hooked to a block device, and the latter is experimental.

Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-11-17 18:21:01 +01:00
Daniel P. Berrange f06033295b qcow2: fix image corruption after committing qcow2 image into base
After committing the qcow2 image contents into the base image, qemu-img
will call bdrv_make_empty to drop the payload in the layered image.

When this is done for qcow2 images, it blows away the LUKS encryption
header, making the resulting image unusable. There are two codepaths
for emptying a qcow2 image, and the second (slower) codepath leaves
the LUKS header intact, so force use of that codepath.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-11-17 13:36:03 +01:00
Daniel P. Berrange f66afbe26f qcow2: don't permit changing encryption parameters
Currently if trying to change encryption parameters on a qcow2 image, qemu-img
will abort. We already explicitly check for attempt to change encrypt.format
but missed other parameters like encrypt.key-secret. Rather than list each
parameter, just blacklist changing of all parameters with a 'encrypt.' prefix.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-11-17 13:35:59 +01:00
Alberto Garcia c9b83e9c23 qcow2: Assert that the crypto header does not overlap other metadata
The crypto header is initialized only when QEMU is creating a new
image, so there's no chance of this happening on a corrupted image.

If QEMU is really trying to allocate the header overlapping other
existing metadata sections then this is a serious bug in QEMU itself
so let's add an assertion.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-id: ae3d77f312fc0c5e0ac2bbd71676c0112eebe2e5.1509718618.git.berto@igalia.com
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-11-14 18:06:25 +01:00
Alberto Garcia 951053a9ec qcow2: Don't open images with header.refcount_table_clusters == 0
qcow2_do_open() is checking that header.refcount_table_clusters is not
too large, but it doesn't check that it's greater than zero. Apart
from the fact that an image like that is obviously corrupted, trying
to use it crashes QEMU since we end up with a null s->refcount_table
after qcow2_refcount_init().

These images can however be repaired, so allow opening them if the
BDRV_O_CHECK flag is set.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: f9750f50c80359babba11062e88f5075a47e8e16.1509718618.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-11-14 18:06:25 +01:00
Max Reitz 572b07bea1 qcow2: Always execute preallocate() in a coroutine
Some qcow2 functions (at least perform_cow()) expect s->lock to be
taken.  Therefore, if we want to make use of them, we should execute
preallocate() (as "preallocate_co") in a coroutine so that we can use
the qemu_co_mutex_* functions.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20171009215533.12530-3-mreitz@redhat.com
Cc: qemu-stable@nongnu.org
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-10-26 15:01:14 +02:00
Max Reitz e400ad1e1f qcow2: Fix unaligned preallocated truncation
A qcow2 image file's length is not required to have a length that is a
multiple of the cluster size.  However, qcow2_refcount_area() expects an
aligned value for its @start_offset parameter, so we need to round
@old_file_size up to the next cluster boundary.

Reported-by: Ping Li <pingl@redhat.com>
Bug: https://bugzilla.redhat.com/show_bug.cgi?id=1414049
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20171009215533.12530-2-mreitz@redhat.com
Cc: qemu-stable@nongnu.org
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-10-26 15:01:14 +02:00
Max Reitz 233521b199 qcow2: Emit errp when truncating the image tail
bdrv_truncate() has an errp parameter which is always set when an error
occurs.  Let's use that instead of a plain strerror().

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20171009155431.14093-1-mreitz@redhat.com
Reviewed-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-10-26 15:01:14 +02:00
Alberto Garcia a35f87f50d qcow2: Use BDRV_SECTOR_BITS instead of its literal value
BDRV_SECTOR_BITS is defined to be 9 in block.h (and BDRV_SECTOR_SIZE
is calculated from that), but there are still a couple of places where
we are using the literal value instead of the macro.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-id: 20171009153856.20387-1-berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-10-26 15:01:13 +02:00
Eric Blake 8cbf74b23c qcow2: Reduce is_zero() rounding
Now that bdrv_is_allocated accepts non-aligned inputs, we can
remove the TODO added in earlier refactoring.

Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-10-26 14:45:57 +02:00
Eric Blake 3182664220 block: Convert bdrv_get_block_status_above() to bytes
We are gradually moving away from sector-based interfaces, towards
byte-based.  In the common case, allocation is unlikely to ever use
values that are not naturally sector-aligned, but it is possible
that byte-based values will let us be more precise about allocation
at the end of an unaligned file that can do byte-based access.

Changing the name of the function from bdrv_get_block_status_above()
to bdrv_block_status_above() ensures that the compiler enforces that
all callers are updated.  Likewise, since it a byte interface allows
an offset mapping that might not be sector aligned, split the mapping
out of the return value and into a pass-by-reference parameter.  For
now, the io.c layer still assert()s that all uses are sector-aligned,
but that can be relaxed when a later patch implements byte-based
block status in the drivers.

For the most part this patch is just the addition of scaling at the
callers followed by inverse scaling at bdrv_block_status(), plus
updates for the new split return interface.  But some code,
particularly bdrv_block_status(), gets a lot simpler because it no
longer has to mess with sectors.  Likewise, mirror code no longer
computes s->granularity >> BDRV_SECTOR_BITS, and can therefore drop
an assertion about alignment because the loop no longer depends on
alignment (never mind that we don't really have a driver that
reports sub-sector alignments, so it's not really possible to test
the effect of sub-sector mirroring).  Fix a neighboring assertion to
use is_power_of_2 while there.

For ease of review, bdrv_get_block_status() was tackled separately.

Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-10-26 14:45:57 +02:00
Eric Blake f06f6b66c7 qcow2: Switch is_zero_sectors() to byte-based
We are gradually converting to byte-based interfaces, as they are
easier to reason about than sector-based.  Convert another internal
function (no semantic change), and rename it to is_zero() in the
process.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-10-26 14:45:57 +02:00
Eric Blake 298a1665a2 block: Allow NULL file for bdrv_get_block_status()
Not all callers care about which BDS owns the mapping for a given
range of the file.  This patch merely simplifies the callers by
consolidating the logic in the common call point, while guaranteeing
a non-NULL file to all the driver callbacks, for no semantic change.
The only caller that does not care about pnum is bdrv_is_allocated,
as invoked by vvfat; we can likewise add assertions that the rest
of the stack does not have to worry about a NULL pnum.

Furthermore, this will also set the stage for a future cleanup: when
a caller does not care about which BDS owns an offset, it would be
nice to allow the driver to optimize things to not have to return
BDRV_BLOCK_OFFSET_VALID in the first place.  In the case of fragmented
allocation (for example, it's fairly easy to create a qcow2 image
where consecutive guest addresses are not at consecutive host
addresses), the current contract requires bdrv_get_block_status()
to clamp *pnum to the limit where host addresses are no longer
consecutive, but allowing a NULL file means that *pnum could be
set to the full length of known-allocated data.

Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-10-26 14:45:57 +02:00
Pavel Butsykin 163bc39d2c qcow2: truncate the tail of the image file after shrinking the image
Now after shrinking the image, at the end of the image file, there might be a
tail that probably will never be used. So we can find the last used cluster and
cut the tail.

Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 20170929121613.25997-3-pbutsykin@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-10-06 16:30:48 +02:00
Pavel Butsykin 76a2a30a99 qcow2: fix return error code in qcow2_truncate()
Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170929121613.25997-2-pbutsykin@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-10-06 16:30:48 +02:00
Daniel P. Berrange 4609742a49 block: convert qcrypto_block_encrypt|decrypt to take bytes offset
Instead of sector offset, take the bytes offset when encrypting
or decrypting data.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170927125340.12360-6-berrange@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-10-06 16:30:47 +02:00
Eric Blake b85ee45334 qcow2: Switch qcow2_measure() to byte-based iteration
This is new code, but it is easier to read if it makes passes over
the image using bytes rather than sectors (and will get easier in
the future when bdrv_get_block_status is converted to byte-based).

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-10-06 16:28:58 +02:00
Pavel Butsykin 46b732cdf3 qcow2: add shrink image support
This patch add shrinking of the image file for qcow2. As a result, this allows
us to reduce the virtual image size and free up space on the disk without
copying the image. Image can be fragmented and shrink is done by punching holes
in the image file.

Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 20170918124230.8152-4-pbutsykin@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-09-26 15:00:32 +02:00
Alistair Francis 55d527a94d Convert remaining error_report() to warn_report()
In a previous patch (3dc6f86936) we
converted uses of error_report("warning:"... to use warn_report()
instead. This was to help standardise on a single method of printing
warnings to the user.

There appears to have been some cases that slipped through in patch sets
applied around the same time, this patch catches the few remaining
cases.

All of the warnings were changed using this command:
  find ./* -type f -exec sed -i \
    's|error_report(".*warning[,:] |warn_report("|Ig' {} +

Indentation fixed up manually afterwards.

Two messages were manually fixed up as well.

Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Max Reitz <mreitz@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Cornelia Huck <cohuck@redhat.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <eec8cba0d5434bd828639e5e45f12182490ff47d.1505158760.git.alistair.francis@xilinx.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-09-19 14:09:34 +02:00
Pavel Butsykin 83a8c775a8 qcow2: move qcow2_store_persistent_dirty_bitmaps() before cache flushing
After calling qcow2_inactivate(), all qcow2 caches must be flushed, but this
may not happen, because the last call qcow2_store_persistent_dirty_bitmaps()
can lead to marking l2/refcont cache as dirty.

Let's move qcow2_store_persistent_dirty_bitmaps() before the caсhe flushing
to fix it.

Cc: qemu-stable@nongnu.org
Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-09-06 14:40:18 +02:00
Marc-André Lureau f7abe0ecd4 qapi: Change data type of the FOO_lookup generated for enum FOO
Currently, a FOO_lookup is an array of strings terminated by a NULL
sentinel.

A future patch will generate enums with "holes".  NULL-termination
will cease to work then.

To prepare for that, store the length in the FOO_lookup by wrapping it
in a struct and adding a member for the length.

The sentinel will be dropped next.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20170822132255.23945-13-marcandre.lureau@redhat.com>
[Basically redone]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1503564371-26090-16-git-send-email-armbru@redhat.com>
[Rebased]
2017-09-04 13:09:13 +02:00
Markus Armbruster 977c736f80 qapi: Mechanically convert FOO_lookup[...] to FOO_str(...)
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1503564371-26090-14-git-send-email-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
2017-09-04 13:09:13 +02:00
Markus Armbruster 5b5f825d44 qapi: Generate FOO_str() macro for QAPI enum FOO
The next commit will put it to use.  May look pointless now, but we're
going to change the FOO_lookup's type, and then it'll help.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1503564371-26090-13-git-send-email-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
2017-09-04 13:09:13 +02:00
Markus Armbruster 06c60b6c46 qapi: Drop superfluous qapi_enum_parse() parameter max
The lookup tables have a sentinel, no need to make callers pass their
size.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1503564371-26090-3-git-send-email-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[Rebased, commit message corrected]
2017-09-04 13:09:13 +02:00
Stefan Hajnoczi 3e4c705212 qcow2: allocate cluster_cache/cluster_data on demand
Most qcow2 files are uncompressed so it is wasteful to allocate (32 + 1)
* cluster_size + 512 bytes upfront.  Allocate s->cluster_cache and
s->cluster_data when the first read operation is performance on a
compressed cluster.

The buffers are freed in .bdrv_close().  .bdrv_open() no longer has any
code paths that can allocate these buffers, so remove the free functions
in the error code path.

This patch can result in significant memory savings when many qcow2
disks are attached or backing file chains are long:

Before 12.81% (1,023,193,088B)
After   5.36% (393,893,888B)

Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170821135530.32344-1-stefanha@redhat.com
Cc: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-08-30 18:02:10 +01:00
Alberto Garcia c3a8fe331e misc: Remove unused Error variables
There's a few cases which we're passing an Error pointer to a function
only to discard it immediately afterwards without checking it. In
these cases we can simply remove the variable and pass NULL instead.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20170829120836.16091-1-berto@igalia.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-08-30 11:58:26 +01:00
Eric Blake d0d5d0e31a qcow2: Check failure of bdrv_getlength()
qcow2_co_pwritev_compressed() should not call bdrv_truncate()
if determining the size failed.

Reported-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-08-11 13:23:47 +02:00
Eric Blake c40fe9c06c qcow2: Drop debugging dump_refcounts()
It's been #if 0'd since its introduction in 2006, commit 585f8587.
We can revive dead code if we need it, but in the meantime, it has
bit-rotted (for example, not checking for failure in bdrv_getlength()).

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-08-11 13:23:45 +02:00
Daniel P. Berrange 0696ae2c92 qcow: fix memory leaks related to encryption
Fix leak of the 'encryptopts' string, which was mistakenly
declared const.

Fix leak of QemuOpts entry which should not have been deleted
from the opts array.

Reported by: coverity
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170714103105.5781-1-berrange@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-25 16:33:31 +02:00
Eric Blake 24bae02b19 qcow2: Fix sector calculation in qcow2_measure()
We used MAX() instead of the intended MIN() when computing how many
sectors to view in the current loop iteration of qcow2_measure(),
and passed in a value of INT_MAX sectors instead of our more usual
limit of BDRV_REQUEST_MAX_SECTORS (the latter avoids 32-bit overflow
on conversion to bytes).  For small files, the bug is harmless:
bdrv_get_block_status_above() clamps its *pnum answer to the BDS
size, regardless of any insanely larger input request.  However, for
any file at least 2T in size, we can very easily end up going into an
infinite loop (the maximum of 0x100000000 sectors and INT_MAX is a
64-bit quantity, which becomes 0 when assigned to int; once nb_sectors
is 0, we never make progress).

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-07-24 15:06:04 +02:00
Paolo Bonzini a8c57408cd qcow2: call CoQueue APIs under CoMutex
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20170629132749.997-2-pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
2017-07-17 11:28:15 +08:00
Max Reitz 772d1f973f block/qcow2: falloc/full preallocating growth
Implement the preallocation modes falloc and full for growing qcow2
images.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170613202107.10125-15-mreitz@redhat.com
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:45:02 +02:00
Max Reitz 12cc30a8cb block/qcow2: Add qcow2_refcount_area()
This function creates a collection of self-describing refcount
structures (including a new refcount table) at the end of a qcow2 image
file. Optionally, these structures can also describe a number of
additional clusters beyond themselves; this will be important for
preallocated truncation, which will place the data clusters and L2
tables there.

For now, we can use this function to replace the part of
alloc_refcount_block() that grows the refcount table (from which it is
actually derived).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170613202107.10125-13-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:45:02 +02:00
Max Reitz 95b98f343b block/qcow2: Metadata preallocation for truncate
We can support PREALLOC_MODE_METADATA by invoking preallocate() in
qcow2_truncate().

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170613202107.10125-12-mreitz@redhat.com
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:45:02 +02:00
Max Reitz 652fecd005 block/qcow2: Lock s->lock in preallocate()
preallocate() is and will be called only from places that do not
otherwise need to lock s->lock: Currently that is qcow2_create2(), as of
a future patch it will be called from qcow2_truncate(), too.

It therefore makes sense to move locking that mutex into preallocate()
itself.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170613202107.10125-11-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:45:02 +02:00
Max Reitz 7bc45dc172 block/qcow2: Generalize preallocate()
This patch adds two new parameters to the preallocate() function so we
will be able to use it not just for preallocating a new image but also
for preallocated image growth.

The offset parameter allows the caller to specify a virtual offset from
which to start preallocating. For newly created images this is always 0,
but for preallocating growth this will be the old image length.

The new_length parameter specifies the supposed new length of the image
(basically the "end offset" for preallocation). During image truncation,
bdrv_getlength() will return the old image length so we cannot rely on
its return value then.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170613202107.10125-10-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:45:02 +02:00
Max Reitz 3a691c50f1 block: Add PreallocMode to blk_truncate()
blk_truncate() itself will pass that value to bdrv_truncate(), and all
callers of blk_truncate() just set the parameter to PREALLOC_MODE_OFF
for now.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170613202107.10125-4-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:45:01 +02:00
Max Reitz 7ea37c3066 block: Add PreallocMode to bdrv_truncate()
For block drivers that just pass a truncate request to the underlying
protocol, we can now pass the preallocation mode instead of aborting if
it is not PREALLOC_MODE_OFF.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170613202107.10125-3-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:45:01 +02:00
Max Reitz 8243ccb743 block: Add PreallocMode to BD.bdrv_truncate()
Add a PreallocMode parameter to the bdrv_truncate() function implemented
by each block driver. Currently, we always pass PREALLOC_MODE_OFF and no
driver accepts anything else.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170613202107.10125-2-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:45:01 +02:00
Stefan Hajnoczi c501c35220 qcow2: add bdrv_measure() support
Use qcow2_calc_prealloc_size() to get the required file size.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20170705125738.8777-7-stefanha@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:45:00 +02:00
Stefan Hajnoczi 0eb4a8c1df qcow2: extract image creation option parsing
The image creation options parsed by qcow2_create() are also needed to
implement .bdrv_measure().  Extract the parsing code, including input
validation.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20170705125738.8777-6-stefanha@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:45:00 +02:00
Stefan Hajnoczi 7c5bcc4212 qcow2: make refcount size calculation conservative
The refcount metadata size calculation is inaccurate and can produce
numbers that are too small.  This is bad because we should calculate a
conservative number - one that is guaranteed to be large enough.

This patch switches the approach to a fixed point calculation because
the existing equation is hard to solve when inaccuracies are taken care
of.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20170705125738.8777-5-stefanha@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:45:00 +02:00
Stefan Hajnoczi 95c67e3bd7 qcow2: extract preallocation calculation function
Calculating the preallocated image size will be needed to implement
.bdrv_measure().  Extract the code out into a separate function.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20170705125738.8777-4-stefanha@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:45:00 +02:00
Vladimir Sementsov-Ogievskiy 469c71edc7 qcow2: add .bdrv_remove_persistent_dirty_bitmap
Realize .bdrv_remove_persistent_dirty_bitmap interface.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 20170628120530.31251-29-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:44:59 +02:00
Vladimir Sementsov-Ogievskiy da0eb242ad qcow2: add .bdrv_can_store_new_dirty_bitmap
Realize .bdrv_can_store_new_dirty_bitmap interface.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170628120530.31251-23-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:44:59 +02:00
Vladimir Sementsov-Ogievskiy 169b879359 qcow2: store bitmaps on reopening image as read-only
Store bitmaps and mark them read-only on reopening image as read-only.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170628120530.31251-21-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:44:58 +02:00
Vladimir Sementsov-Ogievskiy 5f72826e7f qcow2: add persistent dirty bitmaps support
Store persistent dirty bitmaps in qcow2 image.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170628120530.31251-20-vsementsov@virtuozzo.com
[mreitz: Always assign ret in store_bitmap() in case of an error]
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:44:58 +02:00
Vladimir Sementsov-Ogievskiy 1b6b0562db qcow2: support .bdrv_reopen_bitmaps_rw
Realize bdrv_reopen_bitmaps_rw interface.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170628120530.31251-15-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:44:58 +02:00
Vladimir Sementsov-Ogievskiy d1258dd0c8 qcow2: autoloading dirty bitmaps
Auto loading bitmaps are bitmaps in Qcow2, with the AUTO flag set. They
are loaded when the image is opened and become BdrvDirtyBitmaps for the
corresponding drive.

Extra data in bitmaps is not supported for now.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 20170628120530.31251-12-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:44:58 +02:00
Vladimir Sementsov-Ogievskiy 88ddffae8f qcow2: add bitmaps extension
Add bitmap extension as specified in docs/specs/qcow2.txt.
For now, just mirror extension header into Qcow2 state and check
constraints. Also, calculate refcounts for qcow2 bitmaps, to not break
qemu-img check.

For now, disable image resize if it has bitmaps. It will be fixed later.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 20170628120530.31251-9-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:44:57 +02:00
Daniel P. Berrange 0a12f6f80e qcow2: report encryption specific image information
Currently 'qemu-img info' reports a simple "encrypted: yes"
field. This is not very useful now that qcow2 can support
multiple encryption formats. Users want to know which format
is in use and some data related to it.

Wire up usage of the qcrypto_block_get_info() method so that
'qemu-img info' can report about the encryption format
and parameters in use

  $ qemu-img create \
      --object secret,id=sec0,data=123456 \
      -o encrypt.format=luks,encrypt.key-secret=sec0 \
      -f qcow2 demo.qcow2 1G
  Formatting 'demo.qcow2', fmt=qcow2 size=1073741824 \
  encryption=off encrypt.format=luks encrypt.key-secret=sec0 \
  cluster_size=65536 lazy_refcounts=off refcount_bits=16

  $ qemu-img info demo.qcow2
  image: demo.qcow2
  file format: qcow2
  virtual size: 1.0G (1073741824 bytes)
  disk size: 480K
  encrypted: yes
  cluster_size: 65536
  Format specific information:
      compat: 1.1
      lazy refcounts: false
      refcount bits: 16
      encrypt:
          ivgen alg: plain64
          hash alg: sha256
          cipher alg: aes-256
          uuid: 3fa930c4-58c8-4ef7-b3c5-314bb5af21f3
          format: luks
          cipher mode: xts
          slots:
              [0]:
                  active: true
                  iters: 1839058
                  key offset: 4096
                  stripes: 4000
              [1]:
                  active: false
                  key offset: 262144
              [2]:
                  active: false
                  key offset: 520192
              [3]:
                  active: false
                  key offset: 778240
              [4]:
                  active: false
                  key offset: 1036288
              [5]:
                  active: false
                  key offset: 1294336
              [6]:
                  active: false
                  key offset: 1552384
              [7]:
                  active: false
                  key offset: 1810432
          payload offset: 2068480
          master key iters: 438487
      corrupt: false

With the legacy "AES" encryption we just report the format
name

  $ qemu-img create \
      --object secret,id=sec0,data=123456 \
      -o encrypt.format=aes,encrypt.key-secret=sec0 \
      -f qcow2 demo.qcow2 1G
  Formatting 'demo.qcow2', fmt=qcow2 size=1073741824 \
  encryption=off encrypt.format=aes encrypt.key-secret=sec0 \
  cluster_size=65536 lazy_refcounts=off refcount_bits=16

  $ ./qemu-img info demo.qcow2
  image: demo.qcow2
  file format: qcow2
  virtual size: 1.0G (1073741824 bytes)
  disk size: 196K
  encrypted: yes
  cluster_size: 65536
  Format specific information:
      compat: 1.1
      lazy refcounts: false
      refcount bits: 16
      encrypt:
          format: aes
      corrupt: false

Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-20-berrange@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:44:57 +02:00
Daniel P. Berrange 1cd9a787a2 block: pass option prefix down to crypto layer
While the crypto layer uses a fixed option name "key-secret",
the upper block layer may have a prefix on the options. e.g.
"encrypt.key-secret", in order to avoid clashes between crypto
option names & other block option names. To ensure the crypto
layer can report accurate error messages, we must tell it what
option name prefix was used.

Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-19-berrange@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:44:56 +02:00
Daniel P. Berrange c01c214b69 block: remove all encryption handling APIs
Now that all encryption keys must be provided upfront via
the QCryptoSecret API and associated block driver properties
there is no need for any explicit encryption handling APIs
in the block layer. Encryption can be handled transparently
within the block driver. We only retain an API for querying
whether an image is encrypted or not, since that is a
potentially useful piece of metadata to report to the user.

Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-18-berrange@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:44:56 +02:00
Daniel P. Berrange 4652b8f3e1 qcow2: add support for LUKS encryption format
This adds support for using LUKS as an encryption format
with the qcow2 file, using the new encrypt.format parameter
to request "luks" format. e.g.

  # qemu-img create --object secret,data=123456,id=sec0 \
       -f qcow2 -o encrypt.format=luks,encrypt.key-secret=sec0 \
       test.qcow2 10G

The legacy "encryption=on" parameter still results in
creation of the old qcow2 AES format (and is equivalent
to the new 'encryption-format=aes'). e.g. the following are
equivalent:

  # qemu-img create --object secret,data=123456,id=sec0 \
       -f qcow2 -o encryption=on,encrypt.key-secret=sec0 \
       test.qcow2 10G

 # qemu-img create --object secret,data=123456,id=sec0 \
       -f qcow2 -o encryption-format=aes,encrypt.key-secret=sec0 \
       test.qcow2 10G

With the LUKS format it is necessary to store the LUKS
partition header and key material in the QCow2 file. This
data can be many MB in size, so cannot go into the QCow2
header region directly. Thus the spec defines a FDE
(Full Disk Encryption) header extension that specifies
the offset of a set of clusters to hold the FDE headers,
as well as the length of that region. The LUKS header is
thus stored in these extra allocated clusters before the
main image payload.

Aside from all the cryptographic differences implied by
use of the LUKS format, there is one further key difference
between the use of legacy AES and LUKS encryption in qcow2.
For LUKS, the initialiazation vectors are generated using
the host physical sector as the input, rather than the
guest virtual sector. This guarantees unique initialization
vectors for all sectors when qcow2 internal snapshots are
used, thus giving stronger protection against watermarking
attacks.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-14-berrange@redhat.com
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:44:56 +02:00
Daniel P. Berrange b25b387fa5 qcow2: convert QCow2 to use QCryptoBlock for encryption
This converts the qcow2 driver to make use of the QCryptoBlock
APIs for encrypting image content, using the legacy QCow2 AES
scheme.

With this change it is now required to use the QCryptoSecret
object for providing passwords, instead of the current block
password APIs / interactive prompting.

  $QEMU \
    -object secret,id=sec0,file=/home/berrange/encrypted.pw \
    -drive file=/home/berrange/encrypted.qcow2,encrypt.key-secret=sec0

The test 087 could be simplified since there is no longer a
difference in behaviour when using blockdev_add with encrypted
images for the running vs stopped CPU state.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-12-berrange@redhat.com
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:44:56 +02:00
Daniel P. Berrange 446d306d23 qcow2: make qcow2_encrypt_sectors encrypt in place
Instead of requiring separate input/output buffers for
encrypting data, change qcow2_encrypt_sectors() to assume
use of a single buffer, encrypting in place. The current
callers all used the same buffer for input/output already.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-11-berrange@redhat.com
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:44:56 +02:00
Daniel P. Berrange 0cb8d47ba9 block: deprecate "encryption=on" in favor of "encrypt.format=aes"
Historically the qcow & qcow2 image formats supported a property
"encryption=on" to enable their built-in AES encryption. We'll
soon be supporting LUKS for qcow2, so need a more general purpose
way to enable encryption, with a choice of formats.

This introduces an "encrypt.format" option, which will later be
joined by a number of other "encrypt.XXX" options. The use of
a "encrypt." prefix instead of "encrypt-" is done to facilitate
mapping to a nested QAPI schema at later date.

e.g. the preferred syntax is now

  qemu-img create -f qcow2 -o encrypt.format=aes demo.qcow2

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-8-berrange@redhat.com
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:44:55 +02:00
Manos Pitsidianakis f5a5ca7969 block: change variable names in BlockDriverState
Change the 'int count' parameter in *pwrite_zeros, *pdiscard related
functions (and some others) to 'int bytes', as they both refer to bytes.
This helps with code legibility.

Signed-off-by: Manos Pitsidianakis <el13635@mail.ntua.gr>
Message-id: 20170609101808.13506-1-el13635@mail.ntua.gr
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-06-26 14:54:46 +02:00
Alberto Garcia 24990c5b95 qcow2: Use offset_into_cluster() and offset_to_l2_index()
We already have functions for doing these calculations, so let's use
them instead of doing everything by hand. This makes the code a bit
more readable.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-06-26 14:51:13 +02:00
Alberto Garcia ee22a9d869 qcow2: Merge the writing of the COW regions with the guest data
If the guest tries to write data that results on the allocation of a
new cluster, instead of writing the guest data first and then the data
from the COW regions, write everything together using one single I/O
operation.

This can improve the write performance by 25% or more, depending on
several factors such as the media type, the cluster size and the I/O
request size.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-06-26 14:51:13 +02:00
Alberto Garcia a7a6a2bffc qcow2: remove extra local_error variable
Commit d7086422b1 added a local_err
variable global to the qcow2_amend_options() function, so there's no
need to have this other one.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-id: 20170511150337.21470-1-berto@igalia.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-29 15:39:53 +02:00
Eric Blake d2cb36af2b qcow2: Discard/zero clusters by byte count
Passing a byte offset, but sector count, when we ultimately
want to operate on cluster granularity, is madness.  Clean up
the external interfaces to take both offset and count as bytes,
while still keeping the assertion added previously that the
caller must align the values to a cluster.  Then rename things
to make sure backports don't get confused by changed units:
instead of qcow2_discard_clusters() and qcow2_zero_clusters(),
we now have qcow2_cluster_discard() and qcow2_cluster_zeroize().

The internal functions still operate on clusters at a time, and
return an int for number of cleared clusters; but on an image
with 2M clusters, a single L2 table holds 256k entries that each
represent a 2M cluster, totalling well over INT_MAX bytes if we
ever had a request for that many bytes at once.  All our callers
currently limit themselves to 32-bit bytes (and therefore fewer
clusters), but by making this function 64-bit clean, we have one
less place to clean up if we later improve the block layer to
support 64-bit bytes through all operations (with the block layer
auto-fragmenting on behalf of more-limited drivers), rather than
the current state where some interfaces are artificially limited
to INT_MAX at a time.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170507000552.20847-13-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-11 14:28:07 +02:00
Eric Blake fbaa6bb3d3 qcow2: Optimize write zero of unaligned tail cluster
We've already improved discards to operate efficiently on the tail
of an unaligned qcow2 image; it's time to make a similar improvement
to write zeroes.  The special case is only valid at the tail
cluster of a file, where we must recognize that any sectors beyond
the image end would implicitly read as zero, and therefore should
not penalize our logic for widening a partial cluster into writing
the whole cluster as zero.

However, note that for now, the special case of end-of-file is only
recognized if there is no backing file, or if the backing file has
the same length; that's because when the backing file is shorter
than the active layer, we don't have code in place to recognize
that reads of a sector unallocated at the top and beyond the backing
end-of-file are implicitly zero.  It's not much of a real loss,
because most people don't use images that aren't cluster-aligned,
or where the active layer is a different size than the backing
layer (especially where the difference falls within a single cluster).

Update test 154 to cover the new scenarios, using two images of
intentionally differing length.

While at it, fix the test to gracefully skip when run as
./check -qcow2 -o compat=0.10 154
since the older format lacks zero clusters already required earlier
in the test.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170507000552.20847-11-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-11 14:28:07 +02:00
Eric Blake fdfab37dfe qcow2: Make distinction between zero cluster types obvious
Treat plain zero clusters differently from allocated ones, so that
we can simplify the logic of checking whether an offset is present.
Do this by splitting QCOW2_CLUSTER_ZERO into two new enums,
QCOW2_CLUSTER_ZERO_PLAIN and QCOW2_CLUSTER_ZERO_ALLOC.

I tried to arrange the enum so that we could use
'ret <= QCOW2_CLUSTER_ZERO_PLAIN' for all unallocated types, and
'ret >= QCOW2_CLUSTER_ZERO_ALLOC' for allocated types, although
I didn't actually end up taking advantage of the layout.

In many cases, this leads to simpler code, by properly combining
cases (sometimes, both zero types pair together, other times,
plain zero is more like unallocated while allocated zero is more
like normal).

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-id: 20170507000552.20847-7-eblake@redhat.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-11 14:28:07 +02:00
Max Reitz 92413c16be qcow2: Fix preallocation size formula
When calculating the number of reftable entries, we should actually use
the number of refblocks and not (wrongly[1]) re-calculate it.

[1] "Wrongly" means: Dividing the number of clusters by the number of
    entries per refblock and rounding down instead of up.

Reported-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-05-11 12:08:24 +02:00
Eric Blake 46f5ac205a qobject: Use simpler QDict/QList scalar insertion macros
We now have macros in place to make it less verbose to add a scalar
to QDict and QList, so use them.

Patch created mechanically via:
  spatch --sp-file scripts/coccinelle/qobject.cocci \
    --macro-file scripts/cocci-macro-file.h --dir . --in-place
then touched up manually to fix a couple of '?:' back to original
spacing, as well as avoiding a long line in monitor.c.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20170427215821.19397-7-eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2017-05-09 09:13:51 +02:00
Eric Blake 048c5fd1bf qcow2: Allow discard of final unaligned cluster
As mentioned in commit 0c1bd46, we ignored requests to
discard the trailing cluster of an unaligned image.  While
discard is an advisory operation from the guest standpoint,
(and we are therefore free to ignore any request), our
qcow2 implementation exploits the fact that a discarded
cluster reads back as 0.  As long as we discard on cluster
boundaries, we are fine; but that means we could observe
non-zero data leaked at the tail of an unaligned image.

Enhance iotest 66 to cover this case, and fix the implementation
to honor a discard request on the final partial cluster.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-id: 20170407013709.18440-1-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-28 16:02:03 +02:00
Max Reitz f59adb3256 block: Add .bdrv_truncate() error messages
Add missing error messages for the block driver implementations of
.bdrv_truncate(); drop the generic one from block.c's bdrv_truncate().

Since one of these changes touches a mis-indented block in
block/file-posix.c, this patch fixes that coding style issue along the
way.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170328205129.15138-5-mreitz@redhat.com
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-28 16:02:03 +02:00
Max Reitz 4bff28b81a block: Add errp to BD.bdrv_truncate()
Add an Error parameter to the block drivers' bdrv_truncate() interface.
If a block driver does not set this in case of an error, the generic
bdrv_truncate() implementation will do so.

Where it is obvious, this patch also makes some block drivers set this
value.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170328205129.15138-4-mreitz@redhat.com
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-28 16:02:03 +02:00
Max Reitz ed3d2ec98a block: Add errp to b{lk,drv}_truncate()
For one thing, this allows us to drop the error message generation from
qemu-img.c and blockdev.c and instead have it unified in
bdrv_truncate().

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170328205129.15138-3-mreitz@redhat.com
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-28 16:02:02 +02:00
Kevin Wolf 55880601d8 block: Add BDRV_O_RESIZE for blk_new_open()
blk_new_open() is a convenience function that processes flags rather
than QDict options as a simple way to just open an image file.

In order to keep it convenient in the future, it must automatically
request the necessary permissions. This can easily be inferred from the
flags for read and write, but we need another flag that tells us whether
to get the resize permission.

We can't just always request it because that means that no block jobs
can run on the resulting BlockBackend (which is something that e.g.
qemu-img commit wants to do), but we also can't request it never because
most of the .bdrv_create() implementations call blk_truncate().

The solution is to introduce another flag that is passed by all users
that want to resize the image.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2017-02-28 20:40:36 +01:00
Kevin Wolf d7086422b1 block: Add error parameter to blk_insert_bs()
Now that blk_insert_bs() requests the BlockBackend permissions for the
node it attaches to, it can fail. Instead of aborting, pass the errors
to the callers.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
2017-02-28 20:40:36 +01:00
Kevin Wolf 6d0eb64d5c block: Add permissions to blk_new()
We want every user to be specific about the permissions it needs, so
we'll pass the initial permissions as parameters to blk_new(). A user
only needs to call blk_set_perm() if it wants to change the permissions
after the fact.

The permissions are stored in the BlockBackend and applied whenever a
BlockDriverState should be attached in blk_insert_bs().

This does not include actually choosing the right set of permissions
everywhere yet. Instead, the usual FIXME comment is added to each place
and will be addressed in individual patches.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
2017-02-28 20:40:36 +01:00
Kevin Wolf 862f215fab block: Request child permissions in format drivers
This makes use of the .bdrv_child_perm() implementation for formats that
we just added. All format drivers expose the permissions they actually
need nows, so that they can be set accordingly and updated when parents
are attached or detached.

The only format not included here is raw, which was already converted
with the other filter drivers.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
2017-02-28 20:40:36 +01:00
Kevin Wolf 4e4bf5c42c block: Attach bs->file only during .bdrv_open()
The way that attaching bs->file worked was a bit unusual in that it was
the only child that would be attached to a node which is not opened yet.
Because of this, the block layer couldn't know yet which permissions the
driver would eventually need.

This patch moves the point where bs->file is attached to the beginning
of the individual .bdrv_open() implementations, so drivers already know
what they are going to do with the child. This is also more consistent
with how driver-specific children work.

For a moment, bdrv_open() gets its own BdrvChild to perform image
probing, but instead of directly assigning this BdrvChild to the BDS, it
becomes a temporary one and the node name is passed as an option to the
drivers, so that they can simply use bdrv_open_child() to create another
reference for their own use.

This duplicated child for (the not opened yet) bs is not the final
state, a follow-up patch will change the image probing code to use a
BlockBackend, which is completely independent of bs.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2017-02-24 16:09:23 +01:00
Kevin Wolf 52cdbc5869 block: Pass BdrvChild to bdrv_truncate()
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2017-02-24 16:09:23 +01:00
Kevin Wolf 70b27f3643 qcow2: Use BB for resizing in qcow2_amend_options()
In order to able to convert bdrv_truncate() to take a BdrvChild and
later to correctly check the resize permission here, we need to use a
BlockBackend for resizing the image.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2017-02-24 16:09:23 +01:00
Alberto Garcia 7061a07898 qcow2: Optimize the refcount-block overlap check
The metadata overlap checks introduced in a40f1c2add help detect
corruption in the qcow2 image by verifying that data writes don't
overlap with existing metadata sections.

The 'refcount-block' check in particular iterates over the refcount
table in order to get the addresses of all refcount blocks and check
that none of them overlap with the region where we want to write.

The problem with the refcount table is that since it always occupies
complete clusters its size is usually very big. With the default
values of cluster_size=64KB and refcount_bits=16 this table holds 8192
entries, each one of them enough to map 2GB worth of host clusters.

So unless we're using images with several TB of allocated data this
table is going to be mostly empty, and iterating over it is a waste of
CPU. If the storage backend is fast enough this can have an effect on
I/O performance.

This patch keeps the index of the last used (i.e. non-zero) entry in
the refcount table and updates it every time the table changes. The
refcount-block overlap check then uses that index instead of reading
the whole table.

In my tests with a 4GB qcow2 file stored in RAM this doubles the
amount of write IOPS.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-id: 20170201123828.4815-1-berto@igalia.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-02-12 00:47:43 +01:00
Eric Blake a3e1505dae qcow2: Don't strand clusters near 2G intervals during commit
The qcow2_make_empty() function is reached during 'qemu-img commit',
in order to clear out ALL clusters of an image.  However, if the
image cannot use the fast code path (true if the image is format
0.10, or if the image contains a snapshot), the cluster size is
larger than 512, and the image is larger than 2G in size, then our
choice of sector_step causes problems.  Since it is not cluster
aligned, but qcow2_discard_clusters() silently ignores an unaligned
head or tail, we are leaving clusters allocated.

Enhance the testsuite to expose the flaw, and patch the problem by
ensuring our step size is aligned.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-12-06 15:37:02 +01:00
Alberto Garcia 91203f08f0 qcow2: Allow 'cache-clean-interval' in Linux only
The cache-clean-interval option of qcow2 only works on Linux. However
we allow setting it in other systems regardless of whether it works or
not.

In those systems this option is not simply a no-op: it actually
invalidates perfectly valid cache tables for no good reason without
freeing their memory.

This patch forbids using that option in non-Linux systems.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-11-25 13:51:30 +01:00
Eric Blake 49228d1e95 block: Return -ENOTSUP rather than assert on unaligned discards
Right now, the block layer rounds discard requests, so that
individual drivers are able to assert that discard requests
will never be unaligned.  But there are some ISCSI devices
that track and coalesce multiple unaligned requests, turning it
into an actual discard if the requests eventually cover an
entire page, which implies that it is better to always pass
discard requests as low down the stack as possible.

In isolation, this patch has no semantic effect, since the
block layer currently never passes an unaligned request through.
But the block layer already has code that silently ignores
drivers that return -ENOTSUP for a discard request that cannot
be honored (as well as drivers that return 0 even when nothing
was done).  But the next patch will update the block layer to
fragment discard requests, so that clients are guaranteed that
they are either dealing with an unaligned head or tail, or an
aligned core, making it similar to the block layer semantics of
write zero fragmentation.

CC: qemu-stable@nongnu.org
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-11-22 15:59:22 +01:00
Eric Blake ecdbead659 qcow2: Inform block layer about discard boundaries
At the qcow2 layer, discard is only possible on a per-cluster
basis; at the moment, qcow2 silently rounds any unaligned
requests to this granularity.  However, an upcoming patch will
fix a regression in the block layer ignoring too much of an
unaligned discard request, by changing the block layer to
break up a discard request at alignment boundaries; for that
to work, the block layer must know about our limits.

However, we can't go one step further by changing
qcow2_discard_clusters() to assert that requests are always
aligned, since that helper function is reached on paths
outside of the block layer.

CC: qemu-stable@nongnu.org
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-11-22 15:59:22 +01:00
Fam Zheng 170f4b2e5c qcow2: Support BDRV_REQ_MAY_UNMAP
Handling this is similar to what is done to the L2 entry in the case of
compressed clusters.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-10-24 17:54:03 +02:00
Gonglei f844836ddc crypto: extend mode as a parameter in qcrypto_cipher_supports()
It can't guarantee all cipher modes are supported
if one cipher algorithm is supported by a backend.
Let's extend qcrypto_cipher_supports() to take both
the algorithm and mode as parameters.

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2016-10-19 10:09:24 +01:00
Stefan Hajnoczi 0647d47cc1 qcow2: avoid memcpy(dst, NULL, len)
Section "7.1.4 Use of library functions" in the C99 standard says:

  If an argument to a function has an invalid value (such as [...]
  a null pointer [...]) [...] the behavior is undefined.

Additionally the "searching and sorting" functions are specified as
requiring valid pointer values as described in 7.1.4.

This patch fixes the following sanitizer errors:

  block/qcow2.c:1807:41: runtime error: null pointer passed as argument 2, which is declared to never be null
  block/qcow2-cluster.c:86:26: runtime error: null pointer passed as argument 2, which is declared to never be null

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1473758138-19260-1-git-send-email-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-09-13 11:00:55 +01:00
Pavel Butsykin 8b2bd09338 qcow2: fix iovec size at qcow2_co_pwritev_compressed
Use bytes as the size would be more exact than s->cluster_size.  Although
qemu_iovec_to_buf() will not allow to go beyond the qiov.

Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-09-05 19:06:48 +02:00
Pavel Butsykin a2c0ca6f55 qcow2: cleanup qcow2_co_pwritev_compressed to avoid the recursion
Now that the function uses a vector instead of a buffer, there is no
need to use recursive code.

Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Jeff Cody <jcody@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
CC: Eric Blake <eblake@redhat.com>
CC: John Snow <jsnow@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-09-05 19:06:48 +02:00
Pavel Butsykin fcccefc57f qcow2: add qcow2_co_pwritev_compressed
Added implementation of the qcow2_co_pwritev_compressed function that
will allow us to safely use compressed writes for the qcow2 from running
VMs.

Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Jeff Cody <jcody@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
CC: Eric Blake <eblake@redhat.com>
CC: John Snow <jsnow@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-09-05 19:06:48 +02:00
Vladimir Sementsov-Ogievskiy ebf7bba090 qcow2: do not allocate extra memory
There are no needs to allocate more than one cluster, as we set
avail_out for deflate to one cluster.

Zlib docs (http://www.zlib.net/manual.html) says:
"deflate compresses as much data as possible, and stops when the input
buffer becomes empty or the output buffer becomes full."

So, deflate will not write more than avail_out to output buffer. If
there is not enough space in output buffer for compressed data (it may
be larger than input data) deflate just returns Z_OK. (if all data is
compressed and written to output buffer deflate returns Z_STREAM_END).

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 1468515565-81313-1-git-send-email-vsementsov@virtuozzo.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2016-07-26 17:46:37 +02:00
Eric Blake 82e8a7888b qcow2: Switch .bdrv_co_discard() to byte-based
Another step towards killing off sector-based block APIs.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1468624988-423-15-git-send-email-eblake@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-20 14:24:25 +01:00
Paolo Bonzini 0b8b8753e4 coroutine: move entry argument to qemu_coroutine_create
In practice the entry argument is always known at creation time, and
it is confusing that sometimes qemu_coroutine_enter is used with a
non-NULL argument to re-enter a coroutine (this happens in
block/sheepdog.c and tests/test-coroutine.c).  So pass the opaque value
at creation time, for consistency with e.g. aio_bh_new.

Mostly done with the following semantic patch:

@ entry1 @
expression entry, arg, co;
@@
- co = qemu_coroutine_create(entry);
+ co = qemu_coroutine_create(entry, arg);
  ...
- qemu_coroutine_enter(co, arg);
+ qemu_coroutine_enter(co);

@ entry2 @
expression entry, arg;
identifier co;
@@
- Coroutine *co = qemu_coroutine_create(entry);
+ Coroutine *co = qemu_coroutine_create(entry, arg);
  ...
- qemu_coroutine_enter(co, arg);
+ qemu_coroutine_enter(co);

@ entry3 @
expression entry, arg;
@@
- qemu_coroutine_enter(qemu_coroutine_create(entry), arg);
+ qemu_coroutine_enter(qemu_coroutine_create(entry, arg));

@ reentry @
expression co;
@@
- qemu_coroutine_enter(co, NULL);
+ qemu_coroutine_enter(co);

except for the aforementioned few places where the semantic patch
stumbled (as expected) and for test_co_queue, which would otherwise
produce an uninitialized variable warning.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-07-13 13:26:02 +02:00
Peter Maydell f1f7a1ddf3 block/qcow2: Don't use cpu_to_*w()
Don't use the cpu_to_*w() functions, which we are trying to deprecate.
Instead either just use cpu_to_*() to do the byteswap, or use
st*_be_p() if we need to do the store somewhere other than to a
variable that's already the correct type.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1466093177-17890-1-git-send-email-peter.maydell@linaro.org
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2016-07-05 16:54:04 +02:00
Kevin Wolf a03ef88f77 block: Convert bdrv_co_preadv/pwritev to BdrvChild
This is the final patch for converting the common I/O path to take
a BdrvChild parameter instead of BlockDriverState.

The completion of this conversion means that all users that perform I/O
on an image need to actually hold a reference (in the form of BdrvChild,
possible as part of a BlockBackend) to that image. This also protects
against inconsistent use of BlockBackend vs. BlockDriverState functions
because direct use of a BlockDriverState isn't possible any more and
blk->root is private for block-backends.c.

In addition, we can now distinguish different users in the I/O path,
and the future op blockers work is going to add assertions based on
permissions stored in BdrvChild.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-05 16:46:27 +02:00
Kevin Wolf 720ff280e7 block: Convert bdrv_pwrite_zeroes() to BdrvChild
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-05 16:46:27 +02:00