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2021-06-02block: consistently use bdrv_is_read_only()Vladimir Sementsov-Ogievskiy1-3/+2
It's better to use accessor function instead of bs->read_only directly. In some places use bdrv_is_writable() instead of checking both BDRV_O_RDWR set and BDRV_O_INACTIVE not set. In bdrv_open_common() it's a bit strange to add one more variable, but we are going to drop bs->read_only in the next patch, so new ro local variable substitutes it here. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210527154056.70294-2-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2021-05-18qcow2: set bdi->is_dirtyVladimir Sementsov-Ogievskiy1-0/+1
Set bdi->is_dirty, so that qemu-img info could show dirty flag. After this commit the following check will show '"dirty-flag": true': ./build/qemu-img create -f qcow2 -o lazy_refcounts=on x 1M ./build/qemu-io x qemu-io> write 0 1M After "write" command success, kill the qemu-io process: kill -9 <qemu-io pid> ./build/qemu-img info --output=json x This will show '"dirty-flag": true' among other things. (before this commit it shows '"dirty-flag": false') Note, that qcow2's dirty-bit is not a "dirty bit for the image". It only protects qcow2 lazy refcounts feature. So, there are a lot of conditions when qcow2 session may be not closed correctly, but bit is 0. Still, when bit is set, the last session is definitely not finished correctly and it's better to report it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210504160656.462836-1-vsementsov@virtuozzo.com> Tested-by: Kirill Tkhai <ktkhai@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2021-03-30qcow2: Force preallocation with data-file-rawMax Reitz1-0/+34
Setting the qcow2 data-file-raw bit means that you can ignore the qcow2 metadata when reading from the external data file. It does not mean that you have to ignore it, though. Therefore, the data read must be the same regardless of whether you interpret the metadata or whether you ignore it, and thus the L1/L2 tables must all be present and give a 1:1 mapping. This patch changes 244's output: First, the qcow2 file is larger right after creation, because of metadata preallocation. Second, the qemu-img map output changes: Everything that was not explicitly discarded or zeroed is now a data area. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20210326145509.163455-2-mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2021-03-29qcow2: use external virtual timersPavel Dovgalyuk1-3/+4
Regular virtual timers are used to emulate timings related to vCPU and peripheral states. QCOW2 uses timers to clean the cache. These timers should have external flag. In the opposite case they affect the execution and it can't be recorded and replayed. This patch adds external flag to the timer for qcow2 cache clean. Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <161700516327.1141158.8366564693714562536.stgit@pasha-ThinkPad-X280> Signed-off-by: Max Reitz <mreitz@redhat.com>
2021-03-08block/qcow2: refactor qcow2_update_options_prepare error pathsVladimir Sementsov-Ogievskiy1-3/+8
Keep setting ret close to setting errp and don't merge different error paths into one. This way it's more obvious that we don't return error without setting errp. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-Id: <20210202124956.63146-15-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-03-08block/qcow2: simplify qcow2_co_invalidate_cache()Vladimir Sementsov-Ogievskiy1-9/+4
qcow2_do_open correctly sets errp on each failure path. So, we can simplify code in qcow2_co_invalidate_cache() and drop explicit error propagation. Add ERRP_GUARD() as mandated by the documentation in include/qapi/error.h so that error_prepend() is actually called even if errp is &error_fatal. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <20210202124956.63146-13-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-03-08block/qcow2: read_cache_sizes: return status valueVladimir Sementsov-Ogievskiy1-10/+9
It's better to return status together with setting errp. It allows to reduce error propagation. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Greg Kurz <groug@kaod.org> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-Id: <20210202124956.63146-12-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-03-08block/qcow2-bitmap: improve qcow2_load_dirty_bitmaps() interfaceVladimir Sementsov-Ogievskiy1-4/+2
It's recommended for bool functions with errp to return true on success and false on failure. Non-standard interfaces don't help to understand the code. The change is also needed to reduce error propagation. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <20210202124956.63146-10-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-03-08block/qcow2: qcow2_get_specific_info(): drop error propagationVladimir Sementsov-Ogievskiy1-7/+3
Don't use error propagation in qcow2_get_specific_info(). For this refactor qcow2_get_bitmap_info_list, its current interface is rather weird. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210202124956.63146-9-vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> [eblake: separate local 'tail' variable from 'info_list' parameter] Signed-off-by: Eric Blake <eblake@redhat.com>
2021-03-08block: check return value of bdrv_open_child and drop error propagationVladimir Sementsov-Ogievskiy1-3/+3
This patch is generated by cocci script: @@ symbol bdrv_open_child, errp, local_err; expression file; @@ file = bdrv_open_child(..., - &local_err + errp ); - if (local_err) + if (!file) { ... - error_propagate(errp, local_err); ... } with command spatch --sp-file x.cocci --macro-file scripts/cocci-macro-file.h \ --in-place --no-show-diff --max-width 80 --use-gitgrep block Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Greg Kurz <groug@kaod.org> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-Id: <20210202124956.63146-4-vsementsov@virtuozzo.com> [eblake: fix qcow2_do_open() to use ERRP_GUARD, necessary as the only caller to pass allow_none=true] Signed-off-by: Eric Blake <eblake@redhat.com>
2021-02-15block: qcow2: remove the created file on initialization errorMaxim Levitsky1-3/+5
If the qcow initialization fails, we should remove the file if it was already created, to avoid leaving stale files around. We already do this for luks raw images. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-Id: <20201217170904.946013-4-mlevitsk@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2021-01-08Remove superfluous timer_del() callsPeter Maydell1-1/+0
This commit is the result of running the timer-del-timer-free.cocci script on the whole source tree. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Acked-by: Corey Minyard <cminyard@mvista.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20201215154107.3255-4-peter.maydell@linaro.org
2020-11-09block: Fix some code style problems, "foo* bar" should be "foo *bar"shiliyang1-2/+2
There have some code style problems be found when read the block driver code. So I fixes some problems of this error, ERROR: "foo* bar" should be "foo *bar". Signed-off-by: Liyang Shi <shiliyang@huawei.com> Reported-by: Euler Robot <euler.robot@huawei.com> Message-Id: <3211f389-6d22-46c1-4a16-e6a2ba66f070@huawei.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-11-09qcow2: Document and enforce the QCowL2Meta invariantsAlberto Garcia1-4/+15
The QCowL2Meta structure is used to store information about a part of a write request that touches clusters that need changes in their L2 entries. This happens with newly-allocated clusters or subclusters. This structure has changed a bit since it was first created and its current documentation is not quite up-to-date. A write request can span a region consisting of a combination of clusters of different types, and qcow2_alloc_host_offset() can repeatedly call handle_copied() and handle_alloc() to add more clusters to the mix as long as they all are contiguous on the image file. Because of this a write request has a list of QCowL2Meta structures, one for each part of the request that needs changes in the L2 metadata. Each one of them spans nb_clusters and has two copy-on-write regions located immediately before and after the middle region touched by that part of the write request. Even when those regions themselves are empty their offsets must be correct because they are used to know the location of the middle region. This was not always the case but it is not a problem anymore because the only two places where QCowL2Meta structures are created (calculate_l2_meta() and qcow2_co_truncate()) ensure that the copy-on-write regions are correctly defined, and so do assertions like the ones in perform_cow(). The conditional initialization of the 'written_to' variable is therefore unnecessary and is removed by this patch. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20201007161323.4667-1-berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-10-27qcow2: Skip copy-on-write when allocating a zero clusterAlberto Garcia1-16/+19
Since commit c8bb23cbdbe32f5c326365e0a82e1b0e68cdcd8a when a write request results in a new allocation QEMU first tries to see if the rest of the cluster outside the written area contains only zeroes. In that case, instead of doing a normal copy-on-write operation and writing explicit zero buffers to disk, the code zeroes the whole cluster efficiently using pwrite_zeroes() with BDRV_REQ_NO_FALLBACK. This improves performance very significantly but it only happens when we are writing to an area that was completely unallocated before. Zero clusters (QCOW2_CLUSTER_ZERO_*) are treated like normal clusters and are therefore slower to allocate. This happens because the code uses bdrv_is_allocated_above() rather bdrv_block_status_above(). The former is not as accurate for this purpose but it is faster. However in the case of qcow2 the underlying call does already report zero clusters just fine so there is no reason why we cannot use that information. After testing 4KB writes on an image that only contains zero clusters this patch results in almost five times more IOPS. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <6d77cab968c501c44d6e1089b9bc91b04170b49e.1603731354.git.berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-23block/io: fix bdrv_co_block_status_aboveVladimir Sementsov-Ogievskiy1-2/+14
bdrv_co_block_status_above has several design problems with handling short backing files: 1. With want_zeros=true, it may return ret with BDRV_BLOCK_ZERO but without BDRV_BLOCK_ALLOCATED flag, when actually short backing file which produces these after-EOF zeros is inside requested backing sequence. 2. With want_zero=false, it may return pnum=0 prior to actual EOF, because of EOF of short backing file. Fix these things, making logic about short backing files clearer. With fixed bdrv_block_status_above we also have to improve is_zero in qcow2 code, otherwise iotest 154 will fail, because with this patch we stop to merge zeros of different types (produced by fully unallocated in the whole backing chain regions vs produced by short backing files). Note also, that this patch leaves for another day the general problem around block-status: misuse of BDRV_BLOCK_ALLOCATED as is-fs-allocated vs go-to-backing. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20200924194003.22080-2-vsementsov@virtuozzo.com [Fix s/comes/come/ as suggested by Eric Blake --Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-09-15qcow2: Convert qcow2_alloc_cluster_offset() into qcow2_alloc_host_offset()Alberto Garcia1-23/+13
qcow2_alloc_cluster_offset() takes an (unaligned) guest offset and returns the (aligned) offset of the corresponding cluster in the qcow2 image. In practice none of the callers need to know where the cluster starts so this patch makes the function calculate and return the final host offset directly. The function is also renamed accordingly. See 388e581615 for a similar change to qcow2_get_cluster_offset(). Signed-off-by: Alberto Garcia <berto@igalia.com> Message-Id: <9bfef50ec9200d752413be4fc2aeb22a28378817.1599833007.git.berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-09-15qcow2: Make preallocate_co() resize the image to the correct sizeAlberto Garcia1-0/+1
This function preallocates metadata structures and then extends the image to its new size, but that new size calculation is wrong because it doesn't take into account that the host_offset variable is always cluster-aligned. This problem can be reproduced with preallocation=metadata when the original size is not cluster-aligned but the new size is. In this case the final image size will be shorter than expected. qemu-img create -f qcow2 img.qcow2 31k qemu-img resize --preallocation=metadata img.qcow2 128k Signed-off-by: Alberto Garcia <berto@igalia.com> Message-Id: <adeb8b059917b141d5f5b3bd2a016262d3052c79.1599833007.git.berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> [mreitz: Mark compat=0.10 unsupported for iotest 125] Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-09-15qcow2: Return the original error code in qcow2_co_pwrite_zeroes()Alberto Garcia1-1/+1
This function checks the current status of a (sub)cluster in order to see if an unaligned 'write zeroes' request can be done efficiently by simply updating the L2 metadata and without having to write actual zeroes to disk. If the situation does not allow using the fast path then the function returns -ENOTSUP and the caller falls back to writing zeroes. If can happen however that the aforementioned check returns an actual error code so in this case we should pass it to the caller. Signed-off-by: Alberto Garcia <berto@igalia.com> Message-Id: <20200909123739.719-1-berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-09-15qcow2: Handle QCowL2Meta on error in preallocate_co()Alberto Garcia1-23/+17
If qcow2_alloc_cluster_offset() or qcow2_alloc_cluster_link_l2() fail then this function simply returns the error code, potentially leaking the QCowL2Meta structure and leaving stale items in s->cluster_allocs. A second problem is that this function calls qcow2_free_any_clusters() on failure but passing a host cluster offset instead of an L2 entry. Luckily for normal uncompressed clusters a raw offset also works like a valid L2 entry so it works just the same, but we should be using qcow2_free_clusters() instead. This patch fixes both problems by using qcow2_handle_l2meta(). Signed-off-by: Alberto Garcia <berto@igalia.com> Message-Id: <cd3a6b9abd43f9c0b60be413d760f0cacc67eb66.1599573989.git.berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-09-15qcow2: Don't check nb_clusters when removing l2meta from the listAlberto Garcia1-3/+1
In the past, when a new cluster was allocated the l2meta structure was a variable in the stack so it was necessary to have a way to tell whether it had been initialized and contained valid data or not. The nb_clusters field was used for this purpose. Since commit f50f88b9fe this is no longer the case, l2meta (nowadays a pointer to a list) is only allocated when needed and nb_clusters is guaranteed to be > 0 so this check is unnecessary. Signed-off-by: Alberto Garcia <berto@igalia.com> Message-Id: <ab0b67c29c7ba26e598db35f12aa5ab5982539c1.1599150873.git.berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-09-15qcow2: Use macros for the L1, refcount and bitmap table entry sizesAlberto Garcia1-14/+13
This patch replaces instances of sizeof(uint64_t) in the qcow2 driver with macros that indicate what those sizes are actually referring to. Signed-off-by: Alberto Garcia <berto@igalia.com> Message-Id: <20200828110828.13833-1-berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-08-25qcow2: Allow preallocation and backing files if extended_l2 is setAlberto Garcia1-3/+4
Traditional qcow2 images don't allow preallocation if a backing file is set. This is because once a cluster is allocated there is no way to tell that its data should be read from the backing file. Extended L2 entries have individual allocation bits for each subcluster, and therefore it is perfectly possible to have an allocated cluster with all its subclusters unallocated. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <6d5b0f38e7dc5f2f31d8cab1cb92044e9909aece.1594396418.git.berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-08-25qcow2: Add the 'extended_l2' option and the QCOW2_INCOMPAT_EXTL2 bitAlberto Garcia1-6/+60
Now that the implementation of subclusters is complete we can finally add the necessary options to create and read images with this feature, which we call "extended L2 entries". Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <6476caaa73216bd05b7bb2d504a20415e1665176.1594396418.git.berto@igalia.com> [mreitz: %s/5\.1/5.2/; fixed 302's and 303's reference output] Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-08-25qcow2: Add prealloc field to QCowL2MetaAlberto Garcia1-0/+6
This field allows us to indicate that the L2 metadata update does not come from a write request with actual data but from a preallocation request. For traditional images this does not make any difference, but for images with extended L2 entries this means that the clusters are allocated normally in the L2 table but individual subclusters are marked as unallocated. This will allow preallocating images that have a backing file. There is one special case: when we resize an existing image we can also request that the new clusters are preallocated. If the image already had a backing file then we have to hide any possible stale data and zero out the new clusters (see commit 955c7d6687 for more details). In this case the subclusters cannot be left as unallocated so the L2 bitmap must be updated. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <960d4c444a4f5a870e2b47e5da322a73cd9a2f5a.1594396418.git.berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-08-25qcow2: Add subcluster support to qcow2_measure()Alberto Garcia1-7/+13
Extended L2 entries are bigger than normal L2 entries so this has an impact on the amount of metadata needed for a qcow2 file. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <7efae2efd5e36b42d2570743a12576d68ce53685.1594396418.git.berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-08-25qcow2: Add subcluster support to qcow2_co_pwrite_zeroes()Alberto Garcia1-16/+17
This works now at the subcluster level and pwrite_zeroes_alignment is updated accordingly. qcow2_cluster_zeroize() is turned into qcow2_subcluster_zeroize() with the following changes: - The request can now be subcluster-aligned. - The cluster-aligned body of the request is still zeroized using zero_in_l2_slice() as before. - The subcluster-aligned head and tail of the request are zeroized with the new zero_l2_subclusters() function. There is just one thing to take into account for a possible future improvement: compressed clusters cannot be partially zeroized so zero_l2_subclusters() on the head or the tail can return -ENOTSUP. This makes the caller repeat the *complete* request and write actual zeroes to disk. This is sub-optimal because 1) if the head area was compressed we would still be able to use the fast path for the body and possibly the tail. 2) if the tail area was compressed we are writing zeroes to the head and the body areas, which are already zeroized. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <17e05e2ee7e12f10dcf012da81e83ebe27eb3bef.1594396418.git.berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-08-25qcow2: Add subcluster support to handle_alloc_space()Alberto Garcia1-4/+5
The bdrv_co_pwrite_zeroes() call here fills complete clusters with zeroes, but it can happen that some subclusters are not part of the write request or the copy-on-write. This patch makes sure that only the affected subclusters are overwritten. A potential improvement would be to also fill with zeroes the other subclusters if we can guarantee that we are not overwriting existing data. However this would waste more disk space, so we should first evaluate if it's really worth doing. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <b3dc97e8e2240ddb5191a4f930e8fc9653f94621.1594396418.git.berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-08-25qcow2: Handle QCOW2_SUBCLUSTER_UNALLOCATED_ALLOCAlberto Garcia1-3/+9
When dealing with subcluster types there is a new value called QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC that has no equivalent in QCow2ClusterType. This patch handles that value in all places where subcluster types are processed. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <bf09e2e2439a468a901bb96ace411eed9ee50295.1594396418.git.berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-08-25qcow2: Replace QCOW2_CLUSTER_* with QCOW2_SUBCLUSTER_*Alberto Garcia1-34/+36
In order to support extended L2 entries some functions of the qcow2 driver need to start dealing with subclusters instead of clusters. qcow2_get_host_offset() is modified to return the subcluster type instead of the cluster type, and all callers are updated to replace all values of QCow2ClusterType with their QCow2SubclusterType equivalents. This patch only changes the data types, there are no semantic changes. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <f6c29737c295f32cbee74c903c30b01820363b34.1594396418.git.berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-08-25qcow2: Add cluster type parameter to qcow2_get_host_offset()Alberto Garcia1-15/+22
This function returns an integer that can be either an error code or a cluster type (a value from the QCow2ClusterType enum). We are going to start using subcluster types instead of cluster types in some functions so it's better to use the exact data types instead of integers for clarity and in order to detect errors more easily. This patch makes qcow2_get_host_offset() return 0 on success and puts the returned cluster type in a separate parameter. There are no semantic changes. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <396b6eab1859a271551dcd7dcba77f8934aa3c3f.1594396418.git.berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-08-25qcow2: Add l2_entry_size()Alberto Garcia1-4/+4
qcow2 images with subclusters have 128-bit L2 entries. The first 64 bits contain the same information as traditional images and the last 64 bits form a bitmap with the status of each individual subcluster. Because of that we cannot assume that L2 entries are sizeof(uint64_t) anymore. This function returns the proper value for the image. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <d34d578bd0380e739e2dde3e8dd6187d3d249fa9.1594396418.git.berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-08-25qcow2: Add subcluster-related fields to BDRVQcow2StateAlberto Garcia1-0/+5
This patch adds the following new fields to BDRVQcow2State: - subclusters_per_cluster: Number of subclusters in a cluster - subcluster_size: The size of each subcluster, in bytes - subcluster_bits: No. of bits so 1 << subcluster_bits = subcluster_size Images without subclusters are treated as if they had exactly one subcluster per cluster (i.e. subcluster_size = cluster_size). Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <55bfeac86b092fa2c9d182a95cbeb479ff7eca4f.1594396418.git.berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-08-25qcow2: Convert qcow2_get_cluster_offset() into qcow2_get_host_offset()Alberto Garcia1-17/+7
qcow2_get_cluster_offset() takes an (unaligned) guest offset and returns the (aligned) offset of the corresponding cluster in the qcow2 image. In practice none of the callers need to know where the cluster starts so this patch makes the function calculate and return the final host offset directly. The function is also renamed accordingly. There is a pre-existing exception with compressed clusters: in this case the function returns the complete cluster descriptor (containing the offset and size of the compressed data). This does not change with this patch but it is now documented. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <ffae6cdc5ca8950e8280ac0f696dcc376cb07095.1594396418.git.berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-08-25qcow2: Make Qcow2AioTask store the full host offsetAlberto Garcia1-36/+33
The file_cluster_offset field of Qcow2AioTask stores a cluster-aligned host offset. In practice this is not very useful because all users(*) of this structure need the final host offset into the cluster, which they calculate using host_offset = file_cluster_offset + offset_into_cluster(s, offset) There is no reason why Qcow2AioTask cannot store host_offset directly and that is what this patch does. (*) compressed clusters are the exception: in this case what file_cluster_offset was storing was the full compressed cluster descriptor (offset + size). This does not change with this patch but it is documented now. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <07c4b15c644dcf06c9459f98846ac1c4ea96e26f.1594396418.git.berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-07-27qcow2: Fix capitalization of header extension constant.Andrey Shinkevich1-1/+1
Make the capitalization of the hexadecimal numbers consistent for the QCOW2 header extension constants in docs/interop/qcow2.txt. Suggested-by: Eric Blake <eblake@redhat.com> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <1594973699-781898-2-git-send-email-andrey.shinkevich@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2020-07-14block: Add support to warn on backing file change without formatEric Blake1-1/+1
For now, this is a mechanical addition; all callers pass false. But the next patch will use it to improve 'qemu-img rebase -u' when selecting a backing file with no format. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Peter Krempa <pkrempa@redhat.com> Reviewed-by: Ján Tomko <jtomko@redhat.com> Message-Id: <20200706203954.341758-10-eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-14qcow2: Deprecate use of qemu-img amend to change backing fileEric Blake1-0/+5
The use of 'qemu-img amend' to change qcow2 backing files is not tested very well. In particular, our implementation has a bug where if a new backing file is provided without a format, then the prior format is blindly reused, even if this results in data corruption, but this is not caught by iotests. There are also situations where amending other options needs access to the original backing file (for example, on a downgrade to a v2 image, knowing whether a v3 zero cluster must be allocated or may be left unallocated depends on knowing whether the backing file already reads as zero), but the command line does not have a nice way to tell us both the backing file to use for opening the image as well as the backing file to install after the operation is complete. Even if we do allow changing the backing file, it is redundant with the existing ability to change backing files via 'qemu-img rebase -u'. It is time to deprecate this support (leaving the existing behavior intact, even if it is buggy), and at a point in the future, require the use of only 'qemu-img rebase' for adjusting backing chain relations, saving 'qemu-img amend' for changes unrelated to the backing chain. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20200706203954.341758-8-eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-10qapi: Smooth another visitor error checking patternMarkus Armbruster1-5/+2
Convert visit_type_FOO(v, ..., &ptr, &err); ... if (err) { ... } to visit_type_FOO(v, ..., &ptr, errp); ... if (!ptr) { ... } for functions that set @ptr to non-null / null on success / error. Eliminate error_propagate() that are now unnecessary. Delete @err that are now unused. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200707160613.848843-40-armbru@redhat.com>
2020-07-10error: Eliminate error_propagate() with Coccinelle, part 2Markus Armbruster1-9/+4
When all we do with an Error we receive into a local variable is propagating to somewhere else, we can just as well receive it there right away. The previous commit did that with a Coccinelle script I consider fairly trustworthy. This commit uses the same script with the matching of return taken out, i.e. we convert if (!foo(..., &err)) { ... error_propagate(errp, err); ... } to if (!foo(..., errp)) { ... ... } This is unsound: @err could still be read between afterwards. I don't know how to express "no read of @err without an intervening write" in Coccinelle. Instead, I manually double-checked for uses of @err. Suboptimal line breaks tweaked manually. qdev_realize() simplified further to placate scripts/checkpatch.pl. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200707160613.848843-36-armbru@redhat.com>
2020-07-10qemu-option: Use returned bool to check for failureMarkus Armbruster1-2/+1
The previous commit enables conversion of foo(..., &err); if (err) { ... } to if (!foo(..., &err)) { ... } for QemuOpts functions that now return true / false on success / error. Coccinelle script: @@ identifier fun = { opts_do_parse, parse_option_bool, parse_option_number, parse_option_size, qemu_opt_parse, qemu_opt_rename, qemu_opt_set, qemu_opt_set_bool, qemu_opt_set_number, qemu_opts_absorb_qdict, qemu_opts_do_parse, qemu_opts_from_qdict_entry, qemu_opts_set, qemu_opts_validate }; expression list args, args2; typedef Error; Error *err; @@ - fun(args, &err, args2); - if (err) + if (!fun(args, &err, args2)) { ... } A few line breaks tidied up manually. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20200707160613.848843-15-armbru@redhat.com> [Conflict with commit 0b6786a9c1 "block/amend: refactor qcow2 amend options" resolved by rerunning Coccinelle on master's version]
2020-07-06block: drop unallocated_blocks_are_zeroVladimir Sementsov-Ogievskiy1-1/+0
Currently this field only set by qed and qcow2. But in fact, all backing-supporting formats (parallels, qcow, qcow2, qed, vmdk) share these semantics: on unallocated blocks, if there is no backing file they just memset the buffer with zeroes. So, document this behavior for .supports_backing and drop .unallocated_blocks_are_zero Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200528094405.145708-10-vsementsov@virtuozzo.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-07-06block/qcow2: implement blockdev-amendMaxim Levitsky1-0/+39
Currently the implementation only supports amending the encryption options, unlike the qemu-img version Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200608094030.670121-14-mlevitsk@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-07-06block/qcow2: extend qemu-img amend interface with crypto optionsMaxim Levitsky1-9/+62
Now that we have all the infrastructure in place, wire it in the qcow2 driver and expose this to the user. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200608094030.670121-9-mlevitsk@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-07-06block/amend: refactor qcow2 amend optionsMaxim Levitsky1-100/+38
Some qcow2 create options can't be used for amend. Remove them from the qcow2 create options and add generic logic to detect such options in qemu-img Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> [mreitz: Dropped some iotests reference output hunks that became unnecessary thanks to "iotests: Make _filter_img_create more active"] Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200625125548.870061-12-mreitz@redhat.com>
2020-07-06block/amend: separate amend and create options for qemu-imgMaxim Levitsky1-79/+94
Some options are only useful for creation (or hard to be amended, like cluster size for qcow2), while some other options are only useful for amend, like upcoming keyslot management options for luks Since currently only qcow2 supports amend, move all its options to a common macro and then include it in each action option list. In future it might be useful to remove some options which are not supported anyway from amend list, which currently cause an error message if amended. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200608094030.670121-5-mlevitsk@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-07-06block/amend: add 'force' optionMaxim Levitsky1-0/+1
'force' option will be used for some unsafe amend operations. This includes things like erasing last keyslot in luks based formats (which destroys the data, unless the master key is backed up by external means), but that _might_ be desired result. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200608094030.670121-4-mlevitsk@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-07-06qcow2: Fix preallocation on images with unaligned sizesAlberto Garcia1-3/+14
When resizing an image with qcow2_co_truncate() using the falloc or full preallocation modes the code assumes that both the old and new sizes are cluster-aligned. There are two problems with this: 1) The calculation of how many clusters are involved does not always get the right result. Example: creating a 60KB image and resizing it (with preallocation=full) to 80KB won't allocate the second cluster. 2) No copy-on-write is performed, so in the previous example if there is a backing file then the first 60KB of the first cluster won't be filled with data from the backing file. This patch fixes both issues. Signed-off-by: Alberto Garcia <berto@igalia.com> Message-Id: <20200617140036.20311-1-berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-05-28qcow2: Expose bitmaps' size during measureEric Blake1-3/+11
It's useful to know how much space can be occupied by qcow2 persistent bitmaps, even though such metadata is unrelated to the guest-visible data. Report this value as an additional QMP field, present when measuring an existing image and output format that both support bitmaps. Update iotest 178 and 190 to updated output, as well as new coverage in 190 demonstrating non-zero values made possible with the recently-added qemu-img bitmap command (see 3b51ab4b). The new 'bitmaps size:' field is displayed automatically as part of 'qemu-img measure' any time it is present in QMP (that is, any time both the source image being measured and destination format support bitmaps, even if the measurement is 0 because there are no bitmaps present). If the field is absent, it means that no bitmaps can be copied (source, destination, or both lack bitmaps, including when measuring based on size rather than on a source image). This behavior is compatible with an upcoming patch adding 'qemu-img convert --bitmaps': that command will fail in the same situations where this patch omits the field. The addition of a new field demonstrates why we should always zero-initialize qapi C structs; while the qcow2 driver still fully populates all fields, the raw and crypto drivers had to be tweaked to avoid uninitialized data. Consideration was also given towards having a 'qemu-img measure --bitmaps' which errors out when bitmaps are not possible, and otherwise sums the bitmaps into the existing allocation totals rather than displaying as a separate field, as a potential convenience factor. But this was ultimately decided to be more complexity than necessary when the QMP interface was sufficient enough with bitmaps remaining a separate field. See also: https://bugzilla.redhat.com/1779904 Reported-by: Nir Soffer <nsoffer@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20200521192137.1120211-3-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2020-05-19block: Make it easier to learn which BDS support bitmapsEric Blake1-0/+2
Upcoming patches will enhance bitmap support in qemu-img, but in doing so, it turns out to be nice to suppress output when persistent bitmaps make no sense (such as on a qcow2 v2 image). Add a hook to make this easier to query. This patch adds a new callback .bdrv_supports_persistent_dirty_bitmap, rather than trying to shoehorn the answer in via existing callbacks. In particular, while it might have been possible to overload .bdrv_co_can_store_new_dirty_bitmap to special-case a NULL input to answer whether any persistent bitmaps are supported, that is at odds with whether a particular bitmap can be stored (for example, even on an image that supports persistent bitmaps but has currently filled up the maximum number of bitmaps, attempts to store another one should fail); and the new functionality doesn't require coroutine safety. Similarly, we could have added one more piece of information to .bdrv_get_info, but then again, most callers to that function tend to already discard extraneous information, and making it a catch-all rather than a series of dedicated scalar queries hasn't really simplified life. In the future, when we improve the ability to look up bitmaps through a filter, we will probably also want to teach the block layer to automatically let filters pass this request on through. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20200513011648.166876-4-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
generated by cgit v1.1 at 2024-07-11 11:35:23 +0000