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* qcow2: fix null pointer dereferencePhilippe Mathieu-Daudé2017-07-311-2/+2
| | | | | | | | | | | | | It seems this assert() was somehow misplaced. block/qcow2-refcount.c:2193:42: warning: Array access (from variable 'on_disk_reftable') results in a null pointer dereference on_disk_reftable[refblock_index] = refblock_offset; ~~~~~~~~~~~~~~~~ ^ Reported-by: Clang Static Analyzer Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
* block/qcow2: falloc/full preallocating growthMax Reitz2017-07-111-8/+4Star
| | | | | | | | | | 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>
* block/qcow2: Rename "fail_block" to just "fail"Max Reitz2017-07-111-7/+7
| | | | | | | | | | 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>
* block/qcow2: Add qcow2_refcount_area()Max Reitz2017-07-111-84/+183
| | | | | | | | | | | | | | | | | | 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>
* block: Add PreallocMode to bdrv_truncate()Max Reitz2017-07-111-1/+1
| | | | | | | | | | | 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>
* qcow2: add bitmaps extensionVladimir Sementsov-Ogievskiy2017-07-111-0/+6
| | | | | | | | | | | | | | | 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>
* qcow2-refcount: rename inc_refcounts() and make it publicVladimir Sementsov-Ogievskiy2017-07-111-28/+31
| | | | | | | | | | | | | 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>
* qcow2: add support for LUKS encryption formatDaniel P. Berrange2017-07-111-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* qcow2: Make distinction between zero cluster types obviousEric Blake2017-05-111-26/+18Star
| | | | | | | | | | | | | | | | | | | | | | 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>
* qcow2: Name typedef for cluster typeEric Blake2017-05-111-1/+1
| | | | | | | | | | | | | | | | | | 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>
* qcow2: Use consistent switch indentationEric Blake2017-05-111-42/+42
| | | | | | | | | | | 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>
* qcow2: Nicer variable names in qcow2_update_snapshot_refcount()Eric Blake2017-05-111-20/+22
| | | | | | | | | | | | | | | | | | 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>
* block: Add errp to b{lk,drv}_truncate()Max Reitz2017-04-281-1/+4
| | | | | | | | | | | 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>
* block: Pass BdrvChild to bdrv_truncate()Kevin Wolf2017-02-241-1/+1
| | | | | Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
* qcow2: Optimize the refcount-block overlap checkAlberto Garcia2017-02-121-1/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* block: Convert bdrv_discard() to byte-basedEric Blake2016-07-201-3/+1Star
| | | | | | | | | | | | 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>
* block/qcow2: Don't use cpu_to_*w()Peter Maydell2016-07-051-6/+5Star
| | | | | | | | | | | | 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>
* block: Convert bdrv_pwrite(v/_sync) to BdrvChildKevin Wolf2016-07-051-11/+11
| | | | | | Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: Convert bdrv_pread(v) to BdrvChildKevin Wolf2016-07-051-6/+6
| | | | | | Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: Convert bdrv_write() to BdrvChildKevin Wolf2016-07-051-1/+1
| | | | | Signed-off-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
* coccinelle: Remove unnecessary variables for function return valueEduardo Habkost2016-06-201-5/+2Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* qcow/qcow2: Use DIV_ROUND_UPLaurent Vivier2016-06-071-4/+2Star
| | | | | | | | | | | | 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>
* qemu-common: stop including qemu/bswap.h from qemu-common.hPaolo Bonzini2016-05-191-0/+1
| | | | | | | 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>
* include/qemu/osdep.h: Don't include qapi/error.hMarkus Armbruster2016-03-221-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* block: Clean up includesPeter Maydell2016-01-201-0/+1
| | | | | | | | | | | 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>
* qcow2: Point to amend function in checkMax Reitz2015-12-181-0/+3
| | | | | | | | | | | | | | | | | | | | | | | 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>
* qcow2: Add function for refcount order amendmentMax Reitz2015-12-181-0/+447
| | | | | | | | | 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>
* qcow2: Fix potential qemu-img check crash on 32 bit hostsKevin Wolf2015-12-021-1/+1
| | | | | | | | | | | | | | | 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>
* qcow2: avoid misaligned 64bit bswapJohn Snow2015-11-111-4/+7
| | | | | | | | | | | | | 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>
* block: Convert bs->file to BdrvChildKevin Wolf2015-10-161-21/+24
| | | | | | | | | | | 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>
* qcow2: Make qcow2_alloc_bytes() more explicitMax Reitz2015-09-141-0/+6
| | | | | | | | | | | | | | | 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>
* qcow2: Make size_to_clusters() return uint64_tMax Reitz2015-09-141-4/+8
| | | | | | | | | | | | 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>
* qcow2: Rename BDRVQcowState to BDRVQcow2StateKevin Wolf2015-09-141-29/+29
| | | | | | | | | | BDRVQcowState is already used by qcow1, and gdb is always confused which one to use. Rename the qcow2 one so they can be distinguished. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com>
* maint: remove / fix many doubled wordsDaniel P. Berrange2015-09-111-1/+1
| | | | | | | | | | | | Many source files have doubled words (eg "the the", "to to", and so on). Most of these can simply be removed, but a couple were actual mis-spellings (eg "to to" instead of "to do"). There was even one triple word score "to to to" :-) Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
* qcow2: Handle EAGAIN returned from update_refcountJindřich Makovička2015-07-021-10/+12
| | | | | | | | | Fixes a crash during image compression Signed-off-by: Jindřich Makovička <makovick@gmail.com> Tested-by: Richard W.M. Jones <rjones@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* qcow2: make qcow2_cache_put() a void functionAlberto Garcia2015-05-221-24/+5Star
| | | | | | | | | | This function never receives an invalid table pointer, so we can make it void and remove all the error checking code. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: use one single memory block for the L2/refcount cache tablesAlberto Garcia2015-05-221-3/+5
| | | | | | | | | | | | | | | | | | The qcow2 L2/refcount cache contains one separate table for each cache entry. Doing one allocation per table adds unnecessary overhead and it also requires us to store the address of each table separately. Since the size of the cache is constant during its lifetime, it's better to have an array that contains all the tables using one single allocation. In my tests measuring freshly created caches with sizes 128MB (L2) and 32MB (refcount) this uses around 10MB of RAM less. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Flush pending discards before allocating clusterKevin Wolf2015-05-221-0/+5
| | | | | | | | | | | | | | | | | | | | Before a freed cluster can be reused, pending discards for this cluster must be processed. The original assumption was that this was not a problem because discards are only cached during discard/write zeroes operations, which are synchronous so that no concurrent write requests can cause cluster allocations. However, the discard/write zeroes operation itself can allocate a new L2 table (and it has to in order to put zero flags there), so make sure we can cope with the situation. This fixes https://bugs.launchpad.net/bugs/1349972. Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
* Convert (ffs(val) - 1) to ctz32(val)Stefan Hajnoczi2015-04-281-1/+1
| | | | | | | | | | | | | | | | | | | This commit was generated mechanically by coccinelle from the following semantic patch: @@ expression val; @@ - (ffs(val) - 1) + ctz32(val) The call sites have been audited to ensure the ffs(0) - 1 == -1 case never occurs (due to input validation, asserts, etc). Therefore we don't need to worry about the fact that ctz32(0) == 32. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 1427124571-28598-5-git-send-email-stefanha@redhat.com Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Respect new_block in alloc_refcount_block()Max Reitz2015-03-161-2/+14
| | | | | | | | | | | | | | | | | | | | | | When choosing a new place for the refcount table, alloc_refcount_block() tries to infer the number of clusters used so far from its argument cluster_index (which comes from the idea that if any cluster with an index greater than cluster_index was in use, the refcount table would have to be big enough already to describe cluster_index). However, there is a cluster that may be at or after cluster_index, and which is not covered by the refcount structures, and that is the new refcount block new_block. Therefore, it should be taken into account for the blocks_used calculation. Also, because new_block already describes (or is intended to describe) cluster_index, we may not put the new refcount structures there. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 1423598552-24301-2-git-send-email-mreitz@redhat.com Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
* qcow2: More helpers for refcount modificationMax Reitz2015-03-101-2/+119
| | | | | | | | | | | Add helper functions for getting and setting refcounts in a refcount array for any possible refcount order, and choose the correct one during refcount initialization. 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>
* qcow2: Helper function for refcount modificationMax Reitz2015-03-101-53/+73
| | | | | | | | | | | | | | | | | | | | | | | Since refcounts do not always have to be a uint16_t, all refcount blocks and arrays in memory should not have a specific type (thus they become pointers to void) and for accessing them, two helper functions are used (a getter and a setter). Those functions are called indirectly through function pointers in the BDRVQcowState so they may later be exchanged for different refcount orders. With the check and repair functions using this function, the refcount array they are creating will be in big endian byte order; additionally, using realloc_refcount_array() makes the size of this refcount array always cluster-aligned. Both combined allow rebuild_refcount_structure() to drop the bounce buffer which was used to convert parts of the refcount array to big endian byte order and store them on disk. Instead, those parts can now be written directly. [ kwolf: Fixed a build failure on 32 bit and another with old glib ] Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Helper for refcount array reallocationMax Reitz2015-03-101-49/+81
| | | | | | | | | | | | | | | Add a helper function for reallocating a refcount array, independent of the refcount order. The newly allocated space is zeroed and the function handles failed reallocations gracefully. The helper function will always align the buffer size to a cluster boundary; if storing the refcounts in such an array in big endian byte order, this makes it possible to write parts of the array directly as refcount blocks into the image file. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Use 64 bits for refcount valuesMax Reitz2015-03-101-21/+19Star
| | | | | | | | | Refcounts may have a width of up to 64 bits, so qemu should use the same width to represent refcount values internally. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Use unsigned addend for update_refcount()Max Reitz2015-03-101-22/+43
| | | | | | | | | | | | | | | | | update_refcount() and qcow2_update_cluster_refcount() currently take a signed addend. At least one caller passes a value directly derived from an absolute refcount that should be reached ("l2_refcount - 1" in expand_zero_clusters_in_l1()). Therefore, the addend should be unsigned as well; this will be especially important for 64 bit refcounts. Because update_refcount() then no longer knows whether the refcount should be increased or decreased, it now requires an additional flag which specified exactly that. The same applies to qcow2_update_cluster_refcount(). Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Only return status from qcow2_get_refcountMax Reitz2015-03-101-39/+47
| | | | | | | | | | | | | | | | | | | | | | | | Refcounts can theoretically be of type uint64_t; in order to be able to represent the full range, qcow2_get_refcount() cannot use a single variable to represent both all refcount values and also keep some values reserved for errors. One solution would be to add an Error pointer parameter to qcow2_get_refcount(); however, no caller could (currently) pass that error message, so it would have to be emitted immediately and be passed to the next caller by returning -EIO or something similar. Therefore, an Error parameter does not offer any advantages here. The solution applied by this patch is simpler to use. Because no caller would be able to pass the error message, they would have to print it and free it, whereas with this patch the caller only needs to pass the returned integer (which is often a no-op from the code perspective, because that integer will be stored in a variable "ret" which will be returned by the fail path of many callers). Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Do not return new value after refcount updateMax Reitz2015-03-101-10/+15
| | | | | | | | | | | | | | qcow2_update_cluster_refcount() does not have any quick access to the new refcount value, it has to call qcow2_get_refcount(). Some callers do not need that new value at all, others call qcow2_get_refcount() themselves anyway (albeit in a different code path, which can however be easily changed), therefore there is no advantage in making qcow2_update_cluster_refcount() return the new value. Drop it. 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>
* qcow2: Add two new fields to BDRVQcowStateMax Reitz2015-03-101-2/+2
| | | | | | | | | Add two new fields regarding refcount information (the bit width of every entry and the maximum refcount value) to the BDRVQcowState. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Rewrite qcow2_alloc_bytes()Max Reitz2015-02-061-39/+39
| | | | | | | | qcow2_alloc_bytes() is a function with insufficient error handling and an unnecessary goto. This patch rewrites it. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block/qcow2: Make get_refcount() globalMax Reitz2014-11-031-13/+13
| | | | | | | | | | | | | | | | | Reading the refcount of a cluster is an operation which can be useful in all of the qcow2 code, so make that function globally available. While touching this function, amend the comment describing the "addend" parameter: It is (no longer, if it ever was) necessary to have it set to -1 or 1; any value is fine. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Benoît Canet <benoit.canet@nodalink.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Message-id: 1414404776-4919-6-git-send-email-mreitz@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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