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* qcow2: Fix QCOW2_COMPRESSED_SECTOR_MASKMax Reitz2019-11-071-1/+1
| | | | | | | | | | | | Masks for L2 table entries should have 64 bit. Fixes: b6c246942b14d3e0dec46a6c5868ed84e7dbea19 Buglink: https://bugs.launchpad.net/qemu/+bug/1850000 Cc: qemu-stable@nongnu.org Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20191028161841.1198-2-mreitz@redhat.com Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
* qcow2: Add qcow2_check_fix_snapshot_table()Max Reitz2019-10-281-0/+3
| | | | | | | | | | | | | | | | | | | qcow2_check_read_snapshot_table() can perform consistency checks, but it cannot fix everything. Specifically, it cannot allocate new clusters, because that should wait until the refcount structures are known to be consistent (i.e., after qcow2_check_refcounts()). Thus, it cannot call qcow2_write_snapshots(). Do that in qcow2_check_fix_snapshot_table(), which is called after qcow2_check_refcounts(). Currently, there is nothing that would set result->corruptions, so this is a no-op. A follow-up patch will change that. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20191011152814.14791-10-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
* qcow2: Separate qcow2_check_read_snapshot_table()Max Reitz2019-10-281-0/+4
| | | | | | | | | | | | | | | Reading the snapshot table can fail. That is a problem when we want to repair the image. Therefore, stop reading the snapshot table in qcow2_do_open() in check mode. Instead, add a new function qcow2_check_read_snapshot_table() that reads the snapshot table at a later point. In the future, we want to handle errors here and fix them. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20191011152814.14791-9-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
* qcow2: Make qcow2_write_snapshots() publicMax Reitz2019-10-281-0/+1
| | | | | | | | | | Updating the snapshot list will be useful when upgrading a v2 image to v3, so we will need to call this function in qcow2.c. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20191011152814.14791-6-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
* qcow2: Keep unknown extra snapshot dataMax Reitz2019-10-281-0/+7
| | | | | | | | | | | | | | | The qcow2 specification says to ignore unknown extra data fields in snapshot table entries. Currently, we discard it whenever we update the image, which is a bit different from "ignore". This patch makes the qcow2 driver keep all unknown extra data fields when updating an image's snapshot table. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20191011152814.14791-5-mreitz@redhat.com [mreitz: Adjusted comments as proposed by Eric] Signed-off-by: Max Reitz <mreitz@redhat.com>
* qcow2: Add Error ** to qcow2_read_snapshots()Max Reitz2019-10-281-1/+1
| | | | | | | Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20191011152814.14791-4-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
* block/qcow2-bitmap: do not remove bitmaps on reopen-roVladimir Sementsov-Ogievskiy2019-10-171-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | qcow2_reopen_bitmaps_ro wants to store bitmaps and then mark them all readonly. But the latter don't work, as qcow2_store_persistent_dirty_bitmaps removes bitmaps after storing. It's OK for inactivation but bad idea for reopen-ro. And this leads to the following bug: Assume we have persistent bitmap 'bitmap0'. Create external snapshot bitmap0 is stored and therefore removed Commit snapshot now we have no bitmaps Do some writes from guest (*) they are not marked in bitmap Shutdown Start bitmap0 is loaded as valid, but it is actually broken! It misses writes (*) Incremental backup it will be inconsistent So, let's stop removing bitmaps on reopen-ro. But don't rejoice: reopening bitmaps to rw is broken too, so the whole scenario will not work after this patch and we can't enable corresponding test cases in 260 iotests still. Reopening bitmaps rw will be fixed in the following patches. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 20190927122355.7344-7-vsementsov@virtuozzo.com Signed-off-by: John Snow <jsnow@redhat.com>
* block/qcow2-bitmap: drop qcow2_reopen_bitmaps_rw_hint()Vladimir Sementsov-Ogievskiy2019-10-171-2/+0Star
| | | | | | | | | The function is unused, drop it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 20190927122355.7344-6-vsementsov@virtuozzo.com Signed-off-by: John Snow <jsnow@redhat.com>
* block/qcow2: proper locking on bitmap add/remove pathsVladimir Sementsov-Ogievskiy2019-10-171-5/+6
| | | | | | | | | | | | | | | | | | qmp_block_dirty_bitmap_add and do_block_dirty_bitmap_remove do acquire aio context since 0a6c86d024c52b. But this is not enough: we also must lock qcow2 mutex when access in-image metadata. Especially it concerns freeing qcow2 clusters. To achieve this, move qcow2_can_store_new_dirty_bitmap and qcow2_remove_persistent_dirty_bitmap to coroutine context. Since we work in coroutines in correct aio context, we don't need context acquiring in blockdev.c anymore, drop it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 20190920082543.23444-4-vsementsov@virtuozzo.com Signed-off-by: John Snow <jsnow@redhat.com>
* block/dirty-bitmap: return int from bdrv_remove_persistent_dirty_bitmapVladimir Sementsov-Ogievskiy2019-10-171-3/+2Star
| | | | | | | | | It's more comfortable to not deal with local_err. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 20190920082543.23444-3-vsementsov@virtuozzo.com Signed-off-by: John Snow <jsnow@redhat.com>
* block/qcow2: introduce parallel subrequest handling in read and writeVladimir Sementsov-Ogievskiy2019-10-101-0/+3
| | | | | | | | It improves performance for fragmented qcow2 images. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20190916175324.18478-6-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
* block/qcow2: refactor encryption codeMaxim Levitsky2019-09-161-4/+4
| | | | | | | | | | | | | | | | | | | * Change the qcow2_co_{encrypt|decrypt} to just receive full host and guest offsets and use this function directly instead of calling do_perform_cow_encrypt (which is removed by that patch). * Adjust qcow2_co_encdec to take full host and guest offsets as well. * Document the qcow2_co_{encrypt|decrypt} arguments to prevent the bug fixed in former commit from hopefully happening again. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-id: 20190915203655.21638-3-mlevitsk@redhat.com Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> [mreitz: Let perform_cow() return the error value returned by qcow2_co_encrypt(), as proposed by Vladimir] Signed-off-by: Max Reitz <mreitz@redhat.com>
* block/qcow2: implement .bdrv_co_pwritev(_compressed)_partVladimir Sementsov-Ogievskiy2019-08-271-0/+1
| | | | | | | | | | Implement and use new interface to get rid of hd_qiov. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20190604161514.262241-13-vsementsov@virtuozzo.com Message-Id: <20190604161514.262241-13-vsementsov@virtuozzo.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* block: avoid recursive block_status call if possibleVladimir Sementsov-Ogievskiy2019-06-041-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | drv_co_block_status digs bs->file for additional, more accurate search for hole inside region, reported as DATA by bs since 5daa74a6ebc. This accuracy is not free: assume we have qcow2 disk. Actually, qcow2 knows, where are holes and where is data. But every block_status request calls lseek additionally. Assume a big disk, full of data, in any iterative copying block job (or img convert) we'll call lseek(HOLE) on every iteration, and each of these lseeks will have to iterate through all metadata up to the end of file. It's obviously ineffective behavior. And for many scenarios we don't need this lseek at all. However, lseek is needed when we have metadata-preallocated image. So, let's detect metadata-preallocation case and don't dig qcow2's protocol file in other cases. The idea is to compare allocation size in POV of filesystem with allocations size in POV of Qcow2 (by refcounts). If allocation in fs is significantly lower, consider it as metadata-preallocation case. 102 iotest changed, as our detector can't detect shrinked file as metadata-preallocation, which don't seem to be wrong, as with metadata preallocation we always have valid file length. Two other iotests have a slight change in their QMP output sequence: Active 'block-commit' returns earlier because the job coroutine yields earlier on a blocking operation. This operation is loading the refcount blocks in qcow2_detect_metadata_preallocation(). Suggested-by: Denis V. Lunev <den@openvz.org> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: skip writing zero buffers to empty COW areasAnton Nefedov2019-05-281-0/+6
| | | | | | | | | | | | | | | | | If COW areas of the newly allocated clusters are zeroes on the backing image, efficient bdrv_write_zeroes(flags=BDRV_REQ_NO_FALLBACK) can be used on the whole cluster instead of writing explicit zero buffers later in perform_cow(). iotest 060: write to the discarded cluster does not trigger COW anymore. Use a backing image instead. Signed-off-by: Anton Nefedov <anton.nefedov@virtuozzo.com> Message-id: 20190516142749.81019-2-anton.nefedov@virtuozzo.com Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
* qcow2: do encryption in threadsVladimir Sementsov-Ogievskiy2019-05-281-0/+8
| | | | | | | | | | | Do encryption/decryption in threads, like it is already done for compression. This improves asynchronous encrypted io. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20190506142741.41731-9-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
* qcow2-threads: split out generic pathVladimir Sementsov-Ogievskiy2019-05-281-2/+2
| | | | | | | | | | | Move generic part out of qcow2_co_do_compress, to reuse it for encryption and rename things that would be shared with encryption path. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20190506142741.41731-6-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
* qcow2: add separate file for threaded data processing functionsVladimir Sementsov-Ogievskiy2019-05-281-0/+7
| | | | | | | | | | | Move compression-on-threads to separate file. Encryption will be in it too. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20190506142741.41731-3-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
* qcow2.h: add missing includeVladimir Sementsov-Ogievskiy2019-05-281-0/+1
| | | | | | | | | | | | qcow2.h depends on block_int.h. Compilation isn't broken currently only due to block_int.h always included before qcow2.h. Though, it seems better to directly include block_int.h in qcow2.h. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20190506142741.41731-2-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
* qcow2: Define and use QCOW2_COMPRESSED_SECTOR_SIZEAlberto Garcia2019-05-201-0/+4
| | | | | | | | | | | | When an L2 table entry points to a compressed cluster the space used by the data is specified in 512-byte sectors. This size is independent from BDRV_SECTOR_SIZE and is specific to the qcow2 file format. The QCOW2_COMPRESSED_SECTOR_SIZE constant defined in this patch makes this explicit. Signed-off-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Remove BDRVQcow2State.cluster_sectorsAlberto Garcia2019-05-101-1/+0Star
| | | | | | | | | The last user of this field disappeared when we replace the sector-based bdrv_write() with the byte-based bdrv_pwrite(). Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* block/qcow2-bitmap: Allow resizes with persistent bitmapsJohn Snow2019-03-121-0/+1
| | | | | | | | | | | | | | | | | Since we now load all bitmaps into memory anyway, we can just truncate them in-memory and then flush them back to disk. Just in case, we will still check and enforce that this shortcut is valid -- i.e. that any bitmap described on-disk is indeed in-memory and can be modified. If there are any inconsistent bitmaps, we refuse to allow the truncate as we do not actually load these bitmaps into memory, and it isn't safe or reasonable to attempt to truncate corrupted data. Signed-off-by: John Snow <jsnow@redhat.com> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20190311185147.52309-4-vsementsov@virtuozzo.com [vsementsov: drop bitmap flushing, fix block comments style] Signed-off-by: John Snow <jsnow@redhat.com>
* qcow2: Implement data-file-raw create optionKevin Wolf2019-03-081-1/+8
| | | | | | | | | | | Provide an option to force QEMU to always keep the external data file consistent as a standalone read-only raw image. At the moment, this means making sure that write_zeroes requests are forwarded to the data file instead of just updating the metadata, and checking that no backing file is used. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Store data file name in the imageKevin Wolf2019-03-081-0/+1
| | | | | | | | | Rather than requiring that the external data file node is passed explicitly when creating the qcow2 node, store the filename in the designated header extension during .bdrv_create and read it from there as a default during .bdrv_open. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Add basic data-file infrastructureKevin Wolf2019-03-081-1/+3
| | | | | | This adds a .bdrv_open option to specify the external data file node. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: External file I/OKevin Wolf2019-03-081-1/+1
| | | | | | | | | This changes the qcow2 implementation to direct all guest data I/O to s->data_file rather than bs->file, while metadata I/O still uses bs->file. At the moment, this is still always the same, but soon we'll add options to set s->data_file to an external data file. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Return 0/-errno in qcow2_alloc_compressed_cluster_offset()Kevin Wolf2019-03-081-3/+4
| | | | | | | | | | | | | qcow2_alloc_compressed_cluster_offset() used to return the cluster offset for success and 0 for error. This doesn't only conflict with 0 as a valid host offset, but also loses the error code. Similar to the change made to qcow2_alloc_cluster_offset() for uncompressed clusters in commit 148da7ea9d6, make the function return 0/-errno and return the allocated cluster offset in a by-reference parameter. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Don't assume 0 is an invalid cluster offsetKevin Wolf2019-03-081-0/+2
| | | | | | | | | | | | | | | The cluster allocation code uses 0 as an invalid offset that is used in case of errors or as "offset not yet determined". With external data files, a host cluster offset of 0 becomes valid, though. Define a constant INV_OFFSET (which is not cluster aligned and will therefore never be a valid offset) that can be used for such purposes. This removes the additional host_offset == 0 check that commit ff52aab2df5 introduced; the confusion between an invalid offset and (erroneous) allocation at offset 0 is removed with this change. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Prepare qcow2_get_cluster_type() for external data fileKevin Wolf2019-03-081-1/+9
| | | | Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Pass bs to qcow2_get_cluster_type()Kevin Wolf2019-03-081-1/+2
| | | | Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Basic definitions for external data filesKevin Wolf2019-03-081-10/+22
| | | | | | | | | | | This adds basic constants, struct fields and helper function for external data file support to the implementation. QCOW2_INCOMPAT_MASK and QCOW2_AUTOCLEAR_MASK are not updated yet so that opening images with an external data file still fails (we don't handle them correctly yet). Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Add list of bitmaps to ImageInfoSpecificQCow2Andrey Shinkevich2019-02-111-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the 'Format specific information' section of the 'qemu-img info' command output, the supplemental information about existing QCOW2 bitmaps will be shown, such as a bitmap name, flags and granularity: image: /vz/vmprivate/VM1/harddisk.hdd file format: qcow2 virtual size: 64G (68719476736 bytes) disk size: 3.0M cluster_size: 1048576 Format specific information: compat: 1.1 lazy refcounts: true bitmaps: [0]: flags: [0]: in-use [1]: auto name: back-up1 granularity: 65536 [1]: flags: [0]: in-use [1]: auto name: back-up2 granularity: 65536 refcount bits: 16 corrupt: false Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <1549638368-530182-3-git-send-email-andrey.shinkevich@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>
* block: Eliminate the S_1KiB, S_2KiB, ... macrosMarkus Armbruster2019-02-011-5/+5
| | | | | | | | | | | | | | | | | | We define 54 macros for the powers of two >= 1024. We use six, in six macro definitions. Four of them could just as well use the common MiB macro, so do that. The remaining two can't, because they get passed to stringify. Replace the macro by the literal number there. Slightly harder to read in one instance (1048576 vs. S_1MiB), so add a comment there. The other instance is a wash: 65536 vs S_64KiB. 65536 has been good enough for more than seven years there. This effectively reverts commit 540b8492618 and 1240ac558d3. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qemu/queue.h: leave head structs anonymous unless necessaryPaolo Bonzini2019-01-111-1/+4
| | | | | | | | | | | | Most list head structs need not be given a name. In most cases the name is given just in case one is going to use QTAILQ_LAST, QTAILQ_PREV or reverse iteration, but this does not apply to lists of other kinds, and even for QTAILQ in practice this is only rarely needed. In addition, we will soon reimplement those macros completely so that they do not need a name for the head struct. So clean up everything, not giving a name except in the rare case where it is necessary. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* qcow2: aio support for compressed cluster readVladimir Sementsov-Ogievskiy2018-12-141-4/+0Star
| | | | | | | | | | | Allocate buffers locally and release qcow2 lock. Than, reads inside qcow2_co_preadv_compressed may be done in parallel, however all decompression is still done synchronously. Let's improve it in the following commit. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Don't allow overflow during cluster allocationEric Blake2018-11-191-0/+6
| | | | | | | | | | | | | | | | | | | | | | | Our code was already checking that we did not attempt to allocate more clusters than what would fit in an INT64 (the physical maximimum if we can access a full off_t's worth of data). But this does not catch smaller limits enforced by various spots in the qcow2 image description: L1 and normal clusters of L2 are documented as having bits 63-56 reserved for other purposes, capping our maximum offset at 64PB (bit 55 is the maximum bit set). And for compressed images with 2M clusters, the cap drops the maximum offset to bit 48, or a maximum offset of 512TB. If we overflow that offset, we would write compressed data into one place, but try to decompress from another, which won't work. It's actually possible to prove that overflow can cause image corruption without this patch; I'll add the iotests separately in the next commit. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* bloc/qcow2: drop dirty_bitmaps_loaded state variableVladimir Sementsov-Ogievskiy2018-10-291-1/+0Star
| | | | | | | | | | This variable doesn't work as it should, because it is actually cleared in qcow2_co_invalidate_cache() by memset(). Drop it, as the following patch will introduce new behavior. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: John Snow <jsnow@redhat.com> Signed-off-by: John Snow <jsnow@redhat.com>
* qcow2: Set the default cache-clean-interval to 10 minutesLeonid Bloch2018-10-011-1/+3
| | | | | | | | | | | | | | The default cache-clean-interval is set to 10 minutes, in order to lower the overhead of the qcow2 caches (before the default was 0, i.e. disabled). * For non-Linux platforms the default is kept at 0, because cache-clean-interval is not supported there yet. Signed-off-by: Leonid Bloch <lbloch@janustech.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Increase the default upper limit on the L2 cache sizeLeonid Bloch2018-10-011-1/+5
| | | | | | | | | | | | | | | | | | The upper limit on the L2 cache size is increased from 1 MB to 32 MB on Linux platforms, and to 8 MB on other platforms (this difference is caused by the ability to set intervals for cache cleaning on Linux platforms only). This is done in order to allow default full coverage with the L2 cache for images of up to 256 GB in size (was 8 GB). Note, that only the needed amount to cover the full image is allocated. The value which is changed here is just the upper limit on the L2 cache size, beyond which it will not grow, even if the size of the image will require it to. Signed-off-by: Leonid Bloch <lbloch@janustech.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Assign the L2 cache relatively to the image sizeLeonid Bloch2018-10-011-3/+1Star
| | | | | | | | | | | | | | | | | | | | | | | | Sufficient L2 cache can noticeably improve the performance when using large images with frequent I/O. Previously, unless 'cache-size' was specified and was large enough, the L2 cache was set to a certain size without taking the virtual image size into account. Now, the L2 cache assignment is aware of the virtual size of the image, and will cover the entire image, unless the cache size needed for that is larger than a certain maximum. This maximum is set to 1 MB by default (enough to cover an 8 GB image with the default cluster size) but can be increased or decreased using the 'l2-cache-size' option. This option was previously documented as the *maximum* L2 cache size, and this patch makes it behave as such, instead of as a constant size. Also, the existing option 'cache-size' can limit the sum of both L2 and refcount caches, as previously. Signed-off-by: Leonid Bloch <lbloch@janustech.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Make sizes more humanly readableLeonid Bloch2018-10-011-4/+5
| | | | | | | Signed-off-by: Leonid Bloch <lbloch@janustech.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: add overlap check for bitmap directoryVladimir Sementsov-Ogievskiy2018-07-091-21/+24
| | | | | | Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20180705151515.779173-1-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
* qcow2: add compress threadsVladimir Sementsov-Ogievskiy2018-07-051-0/+3
| | | | | | | | | Do data compression in separate threads. This significantly improve performance for qemu-img convert with -W (allow async writes) and -c (compressed) options. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: Free allocated clusters on write errorKevin Wolf2018-06-291-0/+1
| | | | | | | | | | | | | If we managed to allocate the clusters, but then failed to write the data, there's a good chance that we'll still be able to free the clusters again in order to avoid cluster leaks (the refcounts are cached, so even if we can't write them out right now, we may be able to do so when the VM is resumed after a werror=stop/enospc pause). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Tested-by: Eric Blake <eblake@redhat.com>
* qcow2: Give the refcount cache the minimum possible size by defaultAlberto Garcia2018-05-151-4/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The L2 and refcount caches have default sizes that can be overridden using the l2-cache-size and refcount-cache-size (an additional parameter named cache-size sets the combined size of both caches). Unless forced by one of the aforementioned parameters, QEMU will set the unspecified sizes so that the L2 cache is 4 times larger than the refcount cache. This is based on the premise that the refcount metadata needs to be only a fourth of the L2 metadata to cover the same amount of disk space. This is incorrect for two reasons: a) The amount of disk covered by an L2 table depends solely on the cluster size, but in the case of a refcount block it depends on the cluster size *and* the width of each refcount entry. The 4/1 ratio is only valid with 16-bit entries (the default). b) When we talk about disk space and L2 tables we are talking about guest space (L2 tables map guest clusters to host clusters), whereas refcount blocks are used for host clusters (including L1/L2 tables and the refcount blocks themselves). On a fully populated (and uncompressed) qcow2 file, image size > virtual size so there are more refcount entries than L2 entries. Problem (a) could be fixed by adjusting the algorithm to take into account the refcount entry width. Problem (b) could be fixed by increasing a bit the refcount cache size to account for the clusters used for qcow2 metadata. However this patch takes a completely different approach and instead of keeping a ratio between both cache sizes it assigns as much as possible to the L2 cache and the remainder to the refcount cache. The reason is that L2 tables are used for every single I/O request from the guest and the effect of increasing the cache is significant and clearly measurable. Refcount blocks are however only used for cluster allocation and internal snapshots and in practice are accessed sequentially in most cases, so the effect of increasing the cache is negligible (even when doing random writes from the guest). So, make the refcount cache as small as possible unless the user explicitly asks for a larger one. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 9695182c2eb11b77cb319689a1ebaa4e7c9d6591.1523968389.git.berto@igalia.com Signed-off-by: Max Reitz <mreitz@redhat.com>
* qcow2: try load bitmaps only onceVladimir Sementsov-Ogievskiy2018-04-161-0/+1
| | | | | | | | | | | | | Checking reopen by existence of some bitmaps is wrong, as it may be some other bitmaps, or on the other hand, user may remove bitmaps. This criteria is bad. To simplify things and make behavior more predictable let's just add a flag to remember, that we've already tried to load bitmaps on open and do not want do it again. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20180411122606.367301-2-vsementsov@virtuozzo.com [mreitz: Changed comment wording according to Eric Blake's suggestion] Signed-off-by: Max Reitz <mreitz@redhat.com>
* qcow2-bitmap: add qcow2_reopen_bitmaps_rw_hint()Vladimir Sementsov-Ogievskiy2018-03-261-0/+2
| | | | | | | | | | | | Add version of qcow2_reopen_bitmaps_rw, which do the same work but also return a hint about was header updated or not. This will be used in the following fix for bitmaps reloading after migration. 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: 20180320170521.32152-2-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
* qcow2: Generalize validate_table_offset() into qcow2_validate_table()Alberto Garcia2018-03-091-5/+5
| | | | | | | | | | | | | | | | | | | | | This function checks that the offset and size of a table are valid. While the offset checks are fine, the size check is too generic, since it only verifies that the total size in bytes fits in a 64-bit integer. In practice all tables used in qcow2 have much smaller size limits, so the size needs to be checked again for each table using its actual limit. This patch generalizes this function by allowing the caller to specify the maximum size for that table. In addition to that it allows passing an Error variable. The function is also renamed and made public since we're going to use it in other parts of the code. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qcow2: introduce qcow2_write_caches and qcow2_flush_cachesPaolo Bonzini2018-03-091-0/+2
| | | | | | | | | | 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>
* qcow2: Replace align_offset() with ROUND_UP()Alberto Garcia2018-03-021-6/+0Star
| | | | | | | | | | | | | | | | 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>
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