When we try to allocate new clusters we first look for available ones
starting from s->free_cluster_index and once we find them we increase
their reference counts. Before we get to call update_refcount() to do
this last step s->free_cluster_index is already pointing to the next
cluster after the ones we are trying to allocate.
During update_refcount() it may happen however that we also need to
allocate a new refcount block in order to store the refcounts of these
new clusters (and to complicate things further that may also require
us to grow the refcount table). After all this we don't know if the
clusters that we originally tried to allocate are still available, so
we return -EAGAIN to ask the caller to restart the search for free
clusters.
This is what can happen in a common scenario:
1) We want to allocate a new cluster and we see that cluster N is
free.
2) We try to increase N's refcount but all refcount blocks are full,
so we allocate a new one at N+1 (where s->free_cluster_index was
pointing at).
3) Once we're done we return -EAGAIN to look again for a free
cluster, but now s->free_cluster_index points at N+2, so that's
the one we allocate. Cluster N remains unallocated and we have a
hole in the qcow2 file.
This can be reproduced easily:
qemu-img create -f qcow2 -o cluster_size=512 hd.qcow2 1M
qemu-io -c 'write 0 124k' hd.qcow2
After this the image has 132608 bytes (256 clusters), and the refcount
block is full. If we write 512 more bytes it should allocate two new
clusters: the data cluster itself and a new refcount block.
qemu-io -c 'write 124k 512' hd.qcow2
However the image has now three new clusters (259 in total), and the
first one of them is empty (and unallocated):
dd if=hd.qcow2 bs=512c skip=256 count=1 | hexdump -C
If we write larger amounts of data in the last step instead of the 512
bytes used in this example we can create larger holes in the qcow2
file.
What this patch does is reset s->free_cluster_index to its previous
value when alloc_refcount_block() returns -EAGAIN. This way the caller
will try to allocate again the original clusters if they are still
free.
The output of iotest 026 also needs to be updated because now that
images have no holes some tests fail at a different point and the
number of leaked clusters is different.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
'qemu-img check' cannot detect if a snapshot's L1 table is corrupted.
This patch checks the table's offset and size and reports corruption
if the values are not valid.
This patch doesn't add code to fix that corruption yet, only to detect
and report it.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The inactive-l2 overlap check iterates uses the L1 tables from all
snapshots, but it does not validate them first.
We now have a function to take care of this, so let's use it.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
They will be used to avoid recursively taking s->lock during
bdrv_open or bdrv_check.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1516279431-30424-7-git-send-email-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The align_offset() function is equivalent to the ROUND_UP() macro so
there's no need to use the former. The ROUND_UP() name is also a bit
more explicit.
This patch uses ROUND_UP() instead of the slower QEMU_ALIGN_UP()
because align_offset() already requires that the second parameter is a
power of two.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20180215131008.5153-1-berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
qcow2_update_snapshot_refcount() increases the refcount of all
clusters of a given snapshot. In order to do that it needs to load all
its L2 tables and iterate over their entries. Since we'll be loading
L2 slices instead of full tables we need to add an extra loop that
iterates over all slices of each L2 table.
This function doesn't need any additional changes so apart from that
this patch simply updates the variable name from l2_table to l2_slice.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-id: 5f4db199b9637f4833b58487135124d70add8cf0.1517840877.git.berto@igalia.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Adding support for L2 slices to qcow2_update_snapshot_refcount() needs
(among other things) an extra loop that iterates over all slices of
each L2 table.
Putting all changes in one patch would make it hard to read because
all semantic changes would be mixed with pure indentation changes.
To make things easier this patch simply creates a new block and
changes the indentation of all lines of code inside it. Thus, all
modifications in this patch are cosmetic. There are no semantic
changes and no variables are renamed yet. The next patch will take
care of that.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 8ffaa5e55bd51121f80e498f4045b64902a94293.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This function was only using the BlockDriverState parameter to pass it
to qcow2_cache_get_table_addr(). This is no longer necessary so this
parameter can be removed.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: eb0ed90affcf302e5a954bafb5931b5215483d3a.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This function was only using the BlockDriverState parameter to pass it
to qcow2_cache_get_table_idx() and qcow2_cache_table_release(). This
is no longer necessary so this parameter can be removed.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 9724f7e38e763ad3be32627c6b7fe8df9edb1476.1517840877.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This function was only using the BlockDriverState parameter to pass it
to qcow2_cache_get_table_idx(). This is no longer necessary so this
parameter can be removed.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 6f98155489054a457563da77cdad1a66ebb3e896.1517840876.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This function was only using the BlockDriverState parameter to pass it
to qcow2_cache_get_table_idx(). This is no longer necessary so this
parameter can be removed.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 5c40516a91782b083c1428b7b6a41bb9e2679bfb.1517840876.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
We can easily repair unaligned preallocated zero clusters by discarding
them, so why not do it?
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20171110203759.14018-2-mreitz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reported-by: R. Nageswara Sastry <nasastry@in.ibm.com>
Buglink: https://bugs.launchpad.net/qemu/+bug/1728661
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20171110203111.7666-5-mreitz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
If the refcount data is corrupted then we can end up trying to
allocate a new compressed cluster at offset 0 in the image, triggering
an assertion in qcow2_alloc_bytes() that would crash QEMU:
qcow2_alloc_bytes: Assertion `offset' failed.
This patch adds an explicit check for this scenario and a new test
case.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-id: fb53467cf48e95ff3330def1cf1003a5b862b7d9.1509718618.git.berto@igalia.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Each entry in the qcow2 cache contains an offset field indicating the
location of the data in the qcow2 image. If the offset is 0 then it
means that the entry contains no data and is available to be used when
needed.
Because of that it is not possible to store in the cache the first
cluster of the qcow2 image (offset = 0). This is not a problem because
that cluster always contains the qcow2 header and we're not using this
cache for that.
However, if the qcow2 image is corrupted it can happen that we try to
allocate a new refcount block at offset 0, triggering this assertion
and crashing QEMU:
qcow2_cache_entry_mark_dirty: Assertion `c->entries[i].offset != 0' failed
This patch adds an explicit check for this scenario and a new test
case.
This problem was originally reported here:
https://bugs.launchpad.net/qemu/+bug/1728615
Reported-by: R.Nageswara Sastry <nasastry@in.ibm.com>
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 92a2fadd10d58b423f269c1d1a309af161cdc73f.1509718618.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
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>
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>
Whenever l2/refcount table clusters are discarded from the file we can
automatically drop unnecessary content of the cache tables. This reduces
the chance of eviction useful cache data and eliminates inconsistent data
in the cache with the data in the 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: 20170918124230.8152-3-pbutsykin@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
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>
Now alloc_refcount_block() only contains a single fail label, so it
makes more sense to just name it "fail" instead of "fail_block".
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170613202107.10125-14-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
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>
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>
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>
This is needed for the following patch, which will introduce refcounts
checking for qcow2 bitmaps.
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: 20170628120530.31251-8-vsementsov@virtuozzo.com
[mreitz: s/inc_refcounts/qcow2_inc_refcounts_imrt/ in one more (new)
place]
Signed-off-by: Max Reitz <mreitz@redhat.com>
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>
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>
Although it doesn't add all that much type safety (this is C, after
all), it does add a bit of legibility to use the name QCow2ClusterType
instead of a plain int.
In particular, qcow2_get_cluster_offset() has an overloaded return
type; a QCow2ClusterType on success, and -errno on failure; keeping
the cluster type in a separate variable makes it slightly easier for
the next patch to make further computations based on the type.
Suggested-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-id: 20170507000552.20847-6-eblake@redhat.com
[mreitz: Use the new type in two more places (one of them pulled from
the next patch)]
Signed-off-by: Max Reitz <mreitz@redhat.com>
Fix a couple of inconsistent indentations, before an upcoming
patch further tweaks the switch statements.
(best viewed with 'git diff -b').
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170507000552.20847-3-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
In order to keep checkpatch happy when the next patch changes
indentation, we first have to shorten some long lines. The easiest
approach is to use a new variable in place of
'offset & L2E_OFFSET_MASK', except that 'offset' is the best name
for that variable. Change '[old_]offset' to '[old_]entry' to
make room.
While touching things, also fix checkpatch warnings about unusual
'for' statements.
Suggested by Max Reitz <mreitz@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-id: 20170507000552.20847-2-eblake@redhat.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
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>
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>
Another step towards byte-based interfaces everywhere. Replace
the sector-based bdrv_discard() with a new byte-based
bdrv_pdiscard(), which silently ignores any unaligned head
or tail.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1468624988-423-3-git-send-email-eblake@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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>
Use Coccinelle script to replace 'ret = E; return ret' with
'return E'. The script will do the substitution only when the
function return type and variable type are the same.
Manual fixups:
* audio/audio.c: coding style of "read (...)" and "write (...)"
* block/qcow2-cluster.c: wrap line to make it shorter
* block/qcow2-refcount.c: change indentation of wrapped line
* target-tricore/op_helper.c: fix coding style of
"remainder|quotient"
* target-mips/dsp_helper.c: reverted changes because I don't
want to argue about checkpatch.pl
* ui/qemu-pixman.c: fix line indentation
* block/rbd.c: restore blank line between declarations and
statements
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <1465855078-19435-4-git-send-email-ehabkost@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Unused Coccinelle rule name dropped along with a redundant comment;
whitespace touched up in block/qcow2-cluster.c; stale commit message
paragraph deleted]
Signed-off-by: Markus Armbruster <armbru@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: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Move it to the actual users. There are still a few includes of
qemu/bswap.h in headers; removing them is left for future work.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Commit 57cb38b included qapi/error.h into qemu/osdep.h to get the
Error typedef. Since then, we've moved to include qemu/osdep.h
everywhere. Its file comment explains: "To avoid getting into
possible circular include dependencies, this file should not include
any other QEMU headers, with the exceptions of config-host.h,
compiler.h, os-posix.h and os-win32.h, all of which are doing a
similar job to this file and are under similar constraints."
qapi/error.h doesn't do a similar job, and it doesn't adhere to
similar constraints: it includes qapi-types.h. That's in excess of
100KiB of crap most .c files don't actually need.
Add the typedef to qemu/typedefs.h, and include that instead of
qapi/error.h. Include qapi/error.h in .c files that need it and don't
get it now. Include qapi-types.h in qom/object.h for uint16List.
Update scripts/clean-includes accordingly. Update it further to match
reality: replace config.h by config-target.h, add sysemu/os-posix.h,
sysemu/os-win32.h. Update the list of includes in the qemu/osdep.h
comment quoted above similarly.
This reduces the number of objects depending on qapi/error.h from "all
of them" to less than a third. Unfortunately, the number depending on
qapi-types.h shrinks only a little. More work is needed for that one.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
[Fix compilation without the spice devel packages. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.
This commit was created with scripts/clean-includes.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
If a reference count is not representable with the current refcount
order, the image check should point to qemu-img amend for increasing the
refcount order. However, qemu-img amend needs write access to the image
which cannot be provided if the image is marked corrupt; and the image
check will not mark the image consistent unless everything actually is
consistent.
Therefore, if an image is marked corrupt and the image check encounters
a reference count overflow, it cannot be fixed by using qemu-img amend
to increase the refcount order. Instead, one has to use qemu-img convert
to create a completely new copy of the image in this case.
Alternatively, we may want to give the user a way of manually removing
the corrupt flag, maybe through qemu-img amend, but this is not part of
this patch.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Add a function qcow2_change_refcount_order() which allows changing the
refcount order of a qcow2 image.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This crash was caught with qemu-iotests test case 138.
Commit b6d36de already fixed a few 32 bit truncation bugs that could
cause qemu-img check to allocate too little memory and consequently
it would segfault. On 32 bit hosts, there is one more place that needs
to be fixed because size_t was involved in the calculation and is a
32 bit type there.
Cc: qemu-stable@nongnu.org
Reported-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Tested-by: Michael S. Tsirkin <mst@redhat.com>
If we create a buffer directly on the stack by using 12 bytes, there's
no guarantee the 64bit value we want to swap will be aligned, which
could cause errors with undefined behavior.
Spotted with clang -fsanitize=undefined and observed in iotests 15, 26,
44, 115 and 121.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch removes the temporary duplication between bs->file and
bs->file_child by converting everything to BdrvChild.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
In case of -EAGAIN returned by update_refcount(), we should discard the
cluster offset we were trying to allocate and request a new one, because
in theory that old offset might now be taken by a refcount block.
In practice, this was not the case due to update_refcount() generally
returning strictly monotonic increasing cluster offsets. However, this
behavior is not set in stone, and it is also not obvious when looking at
qcow2_alloc_bytes() alone, so we should not rely on it.
Reported-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Sadly, some images may have more clusters than what can be represented
using a plain int. We should be prepared for that case (in
qcow2_check_refcounts() we actually were trying to catch that case, but
since size_to_clusters() truncated the returned value, that check never
did anything useful).
Cc: qemu-stable <qemu-stable@nongnu.org>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
