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* block/qcow2: falloc/full preallocating growthMax Reitz2017-07-111-0/+5
| | | | | | | | | | 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: Add qcow2_refcount_area()Max Reitz2017-07-111-0/+4
| | | | | | | | | | | | | | | | | | 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>
* qcow2: add .bdrv_remove_persistent_dirty_bitmapVladimir Sementsov-Ogievskiy2017-07-111-0/+3
| | | | | | | | | | 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>
* qcow2: add .bdrv_can_store_new_dirty_bitmapVladimir Sementsov-Ogievskiy2017-07-111-0/+4
| | | | | | | | | | 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>
* qcow2: store bitmaps on reopening image as read-onlyVladimir Sementsov-Ogievskiy2017-07-111-0/+1
| | | | | | | | | 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>
* qcow2: add persistent dirty bitmaps supportVladimir Sementsov-Ogievskiy2017-07-111-0/+1
| | | | | | | | | | 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>
* qcow2: support .bdrv_reopen_bitmaps_rwVladimir Sementsov-Ogievskiy2017-07-111-0/+1
| | | | | | | | | | 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>
* qcow2: autoloading dirty bitmapsVladimir Sementsov-Ogievskiy2017-07-111-0/+2
| | | | | | | | | | | | | | 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>
* qcow2: add bitmaps extensionVladimir Sementsov-Ogievskiy2017-07-111-0/+27
| | | | | | | | | | | | | | | 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-Ogievskiy2017-07-111-0/+4
| | | | | | | | | | | | | 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/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: convert QCow2 to use QCryptoBlock for encryptionDaniel P. Berrange2017-07-111-2/+3
| | | | | | | | | | | | | | | | | | | | | | | 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>
* qcow2: make qcow2_encrypt_sectors encrypt in placeDaniel P. Berrange2017-07-111-2/+1Star
| | | | | | | | | | | | 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>
* qcow2: Merge the writing of the COW regions with the guest dataAlberto Garcia2017-06-261-0/+7
| | | | | | | | | | | | | | | 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>
* qcow2: Use unsigned int for both members of Qcow2COWRegionAlberto Garcia2017-06-261-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | Qcow2COWRegion has two attributes: - The offset of the COW region from the start of the first cluster touched by the I/O request. Since it's always going to be positive and the maximum request size is at most INT_MAX, we can use a regular unsigned int to store this offset. - The size of the COW region in bytes. This is guaranteed to be >= 0, so we should use an unsigned type instead. In x86_64 this reduces the size of Qcow2COWRegion from 16 to 8 bytes. It will also help keep some assertions simpler now that we know that there are no negative numbers. The prototype of do_perform_cow() is also updated to reflect these changes. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Discard/zero clusters by byte countEric Blake2017-05-111-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* qcow2: Make distinction between zero cluster types obviousEric Blake2017-05-111-2/+6
| | | | | | | | | | | | | | | | | | | | | | 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 Blake2017-05-111-3/+3
| | | | | | | | | | | | | | | | | | 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: Reuse preallocated zero clustersMax Reitz2017-05-111-0/+3
| | | | | | | | | | | | | | | | Instead of just freeing preallocated zero clusters and completely allocating them from scratch, reuse them. We cannot do this in handle_copied(), however, since this is a COW operation. Therefore, we have to add the new logic to handle_alloc() and simply return the existing offset if it exists. The only catch is that we have to convince qcow2_alloc_cluster_link_l2() not to free the old clusters (because we have reused them). 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>
* qcow2: Optimize the refcount-block overlap checkAlberto Garcia2017-02-121-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* qcow2: Remove stale FIXME commentAlberto Garcia2016-11-111-2/+0Star
| | | | | | | | It was from the time when none of the global functions had a qcow2_ prefix. Signed-off-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Support BDRV_REQ_MAY_UNMAPFam Zheng2016-10-241-1/+2
| | | | | | | | 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>
* Remove unused function declarationsLadi Prosek2016-09-151-1/+0Star
| | | | | | | | Unused function declarations were found using a simple gcc plugin and manually verified by grepping the sources. Signed-off-by: Ladi Prosek <lprosek@redhat.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
* qcow2: Implement .bdrv_co_pwritev()Kevin Wolf2016-06-161-1/+2
| | | | | | | | | | | | This changes qcow2 to implement the byte-based .bdrv_co_pwritev interface rather than the sector-based old one. As preallocation uses the same allocation function as normal writes, and the interface of that function needs to be changed, it is converted in the same patch. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
* qcow2: Use bytes instead of sectors for QCowL2MetaKevin Wolf2016-06-161-10/+3Star
| | | | | | | In preparation for implementing .bdrv_co_pwritev in qcow2. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
* qcow2: Implement .bdrv_co_preadv()Kevin Wolf2016-06-161-1/+1
| | | | | | | | | | | | Reading from qcow2 images is now byte granularity. Most of the affected code in qcow2 actually gets simpler with this change. The only exception is encryption, which is fixed on 512 bytes blocks; in order to keep this working, bs->request_alignment is set for encrypted images. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
* qcow2: avoid extra flushes in qcow2Denis V. Lunev2016-06-081-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The problem with excessive flushing was found by a couple of performance tests: - parallel directory tree creation (from 2 processes) - 32 cached writes + fsync at the end in a loop For the first one results improved from 2.6 loops/sec to 3.5 loops/sec. Each loop creates 10^3 directories with 10 files in each. For the second one results improved from ~600 fsync/sec to ~1100 fsync/sec. Though, it was run on SSD so it probably won't show such performance gain on rotational media. qcow2_cache_flush() calls bdrv_flush() unconditionally after writing cache entries of a particular cache. This can lead to as many as 2 additional fdatasyncs inside bdrv_flush. We can simply skip all fdatasync calls inside qcow2_co_flush_to_os as bdrv_flush for sure will do the job. These flushes are necessary to keep the right order of writes to the different caches. Though this is not necessary in the current code base as this ordering is ensured through the flush in qcow2_cache_flush_dependency(). Signed-off-by: Denis V. Lunev <den@openvz.org> CC: Pavel Borzenkov <pborzenkov@virtuozzo.com> CC: Kevin Wolf <kwolf@redhat.com> CC: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Add function for refcount order amendmentMax Reitz2015-12-181-0/+4
| | | | | | | | | 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>
* block: Add opaque value to the amend CBMax Reitz2015-12-181-1/+2
| | | | | | | | | | | Add an opaque value which is to be passed to the bdrv_amend_options() status callback. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* coroutine: move into libqemuutil.a libraryDaniel P. Berrange2015-10-201-1/+1
| | | | | | | | | | | | | | | | | The coroutine files are currently referenced by the block-obj-y variable. The coroutine functionality though is already used by more than just the block code. eg migration code uses coroutine yield. In the future the I/O channel code will also use the coroutine yield functionality. Since the coroutine code is nicely self-contained it can be easily built as part of the libqemuutil.a library, making it widely available. The headers are also moved into include/qemu, instead of the include/block directory, since they are now part of the util codebase, and the impl was never in the block/ directory either. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
* qcow2: Remove forward declaration of QCowAIOCBKevin Wolf2015-10-161-2/+0Star
| | | | | | | | This struct doesn't exist any more since commit 3fc48d09 in August 2011, it's about time to remove its forward declaration. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
* qcow2: Make size_to_clusters() return uint64_tMax Reitz2015-09-141-3/+3
| | | | | | | | | | | | 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 Wolf2015-09-141-11/+11
| | | | | | | | | | 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>
* qcow2: add option to clean unused cache entries after some timeAlberto Garcia2015-09-041-0/+4
| | | | | | | | | | | | | | | | | | This adds a new 'cache-clean-interval' option that cleans all qcow2 cache entries that haven't been used in a certain interval, given in seconds. This allows setting a large L2 cache size so it can handle scenarios with lots of I/O and at the same time use little memory during periods of inactivity. This feature currently relies on MADV_DONTNEED to free that memory, so it is not useful in systems that don't follow that behavior. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: a70d12da60433df9360ada648b3f34b8f6f354ce.1438690126.git.berto@igalia.com Signed-off-by: Max Reitz <mreitz@redhat.com>
* block: convert qcow/qcow2 to use generic cipher APIDaniel P. Berrange2015-07-081-8/+5Star
| | | | | | | | | | Switch the qcow/qcow2 block driver over to use the generic cipher API, this allows it to use the pluggable AES implementations, instead of being hardcoded to use QEMU's built-in impl. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-Id: <1435770638-25715-10-git-send-email-berrange@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* crypto: move built-in AES implementation into crypto/Daniel P. Berrange2015-07-071-1/+1
| | | | | | | | | To prepare for a generic internal cipher API, move the built-in AES implementation into the crypto/ directory Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-Id: <1435770638-25715-3-git-send-email-berrange@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* qcow2: Add DEFAULT_L2_CACHE_CLUSTERSMax Reitz2015-06-121-0/+2
| | | | | | | | | | | | | | | | If a relatively large cluster size is chosen, the default of 1 MB L2 cache is not really appropriate. In this case, unless overridden by the user, the default cache size should not be determined by its size in bytes but by the number of L2 tables (clusters) it is supposed to contain. Note that without this patch, MIN_L2_CACHE_SIZE will effectively take over the same role. However, providing space for just two L2 tables is not enough to be the default. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Set MIN_L2_CACHE_SIZE to 2Max Reitz2015-06-121-1/+2
| | | | | | | | | | | | The L2 cache must cover at least two L2 tables, because during COW two L2 tables are accessed simultaneously. Reported-by: Alexander Graf <agraf@suse.de> Cc: qemu-stable <qemu-stable@nongnu.org> Signed-off-by: Max Reitz <mreitz@redhat.com> Tested-by: Alexander Graf <agraf@suse.de> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: make qcow2_cache_put() a void functionAlberto Garcia2015-05-221-1/+1
| | | | | | | | | | 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 Garcia2015-05-221-1/+2
| | | | | | | | | | | | | | | | | | 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: Fix header update with overridden backing fileKevin Wolf2015-04-081-0/+6
| | | | | | | | | | | | | | | | | In recent qemu versions, it is possible to override the backing file name and format that is stored in the image file with values given at runtime. In such cases, the temporary override could end up in the image header if the qcow2 header was updated, while obviously correct behaviour would be to leave the on-disk backing file path/format unchanged. Fix this and add a test case for it. Reported-by: Michael Tokarev <mjt@tls.msk.ru> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 1428411796-2852-1-git-send-email-kwolf@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* qcow2: Helper function for refcount modificationMax Reitz2015-03-101-0/+8
| | | | | | | | | | | | | | | | | | | | | | | 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: Use 64 bits for refcount valuesMax Reitz2015-03-101-3/+3
| | | | | | | | | 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 Reitz2015-03-101-1/+7
| | | | | | | | | | | | | | | | | 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 Reitz2015-03-101-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | 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: Add two new fields to BDRVQcowStateMax Reitz2015-03-101-0/+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: Remove unused struct QCowCreateStateKevin Wolf2015-03-091-11/+0Star
| | | | | | | | | The only user went away five years ago with commit a9420734 ('qcow2: Simplify image creation'). It's about time to remove it. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
* block/qcow2: Make get_refcount() globalMax Reitz2014-11-031-0/+2
| | | | | | | | | | | | | | | | | 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>
* block/qcow2: Implement status CB for amendMax Reitz2014-11-031-1/+2
| | | | | | | | | | | | | | | | | | The only really time-consuming operation potentially performed by qcow2_amend_options() is zero cluster expansion when downgrading qcow2 images from compat=1.1 to compat=0.10, so report status of that operation and that operation only through the status CB. For this, approximate the progress as the number of L1 entries visited during the operation. 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: 1414404776-4919-5-git-send-email-mreitz@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* qcow2: Allow "full" discardMax Reitz2014-11-031-1/+1
| | | | | | | | | | | | | Normally, discarded sectors should read back as zero. However, there are cases in which a sector (or rather cluster) should be discarded as if they were never written in the first place, that is, reading them should fall through to the backing file again. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-id: 1414159063-25977-2-git-send-email-mreitz@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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