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2015-06-12qcow2: Add DEFAULT_L2_CACHE_CLUSTERSMax Reitz1-0/+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>
2015-06-12qcow2: Set MIN_L2_CACHE_SIZE to 2Max Reitz1-1/+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>
2015-05-22qcow2: make qcow2_cache_put() a void functionAlberto Garcia1-1/+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>
2015-05-22qcow2: use one single memory block for the L2/refcount cache tablesAlberto Garcia1-1/+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>
2015-04-08qcow2: Fix header update with overridden backing fileKevin Wolf1-0/+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>
2015-03-10qcow2: Helper function for refcount modificationMax Reitz1-0/+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>
2015-03-10qcow2: Use 64 bits for refcount valuesMax Reitz1-3/+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>
2015-03-10qcow2: Use unsigned addend for update_refcount()Max Reitz1-1/+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>
2015-03-10qcow2: Only return status from qcow2_get_refcountMax Reitz1-1/+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>
2015-03-10qcow2: Add two new fields to BDRVQcowStateMax Reitz1-0/+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>
2015-03-09qcow2: Remove unused struct QCowCreateStateKevin Wolf1-11/+0
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>
2014-11-03block/qcow2: Make get_refcount() globalMax Reitz1-0/+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>
2014-11-03block/qcow2: Implement status CB for amendMax Reitz1-1/+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>
2014-11-03qcow2: Allow "full" discardMax Reitz1-1/+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>
2014-10-23qcow2: Drop REFCOUNT_SHIFTMax Reitz1-2/+0
With BDRVQcowState.refcount_block_bits, we don't need REFCOUNT_SHIFT anymore. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-23qcow2: Calculate refcount block entry countMax Reitz1-0/+2
The size of a refblock entry is (in theory) variable; calculate therefore the number of entries per refblock and the according bit shift (1 << x == entry count) when opening an image. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-22qcow2: Add overlap-check.template optionMax Reitz1-0/+1
Being able to set the overlap-check option to a string and then refine it via the overlap-check.* options is a nice idea for the command line but does not work so well for non-flattened dicts. In that case, one can only specify either but not both, so add a field to overlap-check.* which does the same as directly specifying overlap-check but can be used in conjunction with the other fields in non-flattened dicts. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 1408557576-14574-4-git-send-email-mreitz@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-22qcow2: Add qcow2_signal_corruption()Max Reitz1-0/+5
Add a helper function for easily marking an image corrupt (on fatal corruptions) while outputting an informative message to stderr and via QAPI. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Benoît Canet <benoit.canet@nodalink.com> Message-id: 1409926039-29044-3-git-send-email-mreitz@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-20qcow2: Add runtime options for cache sizesMax Reitz1-0/+3
Add options for specifying the size of the metadata caches. This can either be done directly for each cache (if only one is given, the other will be derived according to a default ratio) or combined for both. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-20qcow2: Constant cache size in bytesMax Reitz1-2/+8
Specifying the metadata cache sizes in clusters results in less clusters (and much less bytes) covered for small cluster sizes and vice versa. Using a constant byte size reduces this difference, and makes it possible to manually specify the cache size in an easily comprehensible unit. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-04-01qcow2: Limit snapshot table sizeKevin Wolf1-0/+4
Even with a limit of 64k snapshots, each snapshot could have a filename and an ID with up to 64k, which would still lead to pretty large allocations, which could potentially lead to qemu aborting. Limit the total size of the snapshot table to an average of 1k per entry when the limit of 64k snapshots is fully used. This should be plenty for any reasonable user. This also fixes potential integer overflows of s->snapshot_size. Suggested-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-04-01qcow2: Check maximum L1 size in qcow2_snapshot_load_tmp() (CVE-2014-0143)Kevin Wolf1-0/+4
This avoids an unbounded allocation. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-04-01qcow2: Fix types in qcow2_alloc_clusters and alloc_clusters_norefKevin Wolf1-3/+3
In order to avoid integer overflows. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-04-01qcow2: Check new refcount table size on growthKevin Wolf1-0/+9
If the size becomes larger than what qcow2_open() would accept, fail the growing operation. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-04-01qcow2: Validate snapshot table offset/size (CVE-2014-0144)Kevin Wolf1-1/+28
This avoid unbounded memory allocation and fixes a potential buffer overflow on 32 bit hosts. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-02-09qcow2: remove n_start and n_end of qcow2_alloc_cluster_offset()Hu Tao1-1/+1
n_start can be actually calculated from offset. The number of sectors to be allocated(n_end - n_start) can be passed in in num. By removing n_start and n_end, we can save two parameters. The side effect is there is a bug in qcow2.c:preallocate() that passes incorrect n_start to qcow2_alloc_cluster_offset() is fixed. The bug can be triggerred by a larger cluster size than the default value(65536), for example: ./qemu-img create -f qcow2 \ -o 'cluster_size=131072,preallocation=metadata' file.img 4G Signed-off-by: Hu Tao <hutao@cn.fujitsu.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-01-24qcow2: fix wrong value of L1E_OFFSET_MASK, L2E_OFFSET_MASK and REFT_OFFSET_MASKHu Tao1-3/+3
Accoring to qcow spec, the offset fields in l1e, l2e and ref table entry start at bit 9. The offset is cluster offset, and the smallest possible cluster size is 512 bytes. Signed-off-by: Hu Tao <hutao@cn.fujitsu.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-12-04snapshot: distinguish id and name in load_tmpWenchao Xia1-1/+4
Since later this function will be used so improve it. The only caller of it now is qemu-img, and it is not impacted by introduce function bdrv_snapshot_load_tmp_by_id_or_name() that call bdrv_snapshot_load_tmp() twice to keep old search logic. bdrv_snapshot_load_tmp_by_id_or_name() return int to let caller know the errno, and errno will be used later. Also fix a typo in comments of bdrv_snapshot_delete(). Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-10-11qcow2: Add more overlap check bitmask macrosMax Reitz1-3/+11
Introduces the macros QCOW2_OL_CONSTANT and QCOW2_OL_ALL in addition to the already existing QCOW2_OL_CACHED, signifying all metadata overlap checks that can be performed in constant time (regardless of image size etc.) and truly all available overlap checks, respectively. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-11qcow2: Add overlap-check optionsMax Reitz1-0/+9
Add runtime options to tune the overlap checks to be performed before write accesses. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-11qcow2: Make overlap check mask variableMax Reitz1-3/+2
Replace the QCOW2_OL_DEFAULT macro by a variable overlap_check in BDRVQcowState. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-11qcow2: Use negated overflow check maskMax Reitz1-2/+2
In qcow2_check_metadata_overlap and qcow2_pre_write_overlap_check, change the parameter signifying the checks to perform from its current positive form to a negative one, i.e., it will no longer explicitly specify every check to perform but rather a mask of checks not to perform. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-25block: qcow2 - used QEMU_PACKED for on-disk structuresJeff Cody1-1/+1
QCowHeader and QCowExtension are structs that reside in the on-disk image format, and are read and written directly via bdrv_pread()/write(), and as such should be packed to avoid any unintentional struct padding. Signed-off-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-12snapshot: distinguish id and name in snapshot deleteWenchao Xia1-1/+4
Snapshot creation actually already distinguish id and name since it take a structured parameter *sn, but delete can't. Later an accurate delete is needed in qmp_transaction abort and blockdev-snapshot-delete-sync, so change its prototype. Also *errp is added to tip error, but return value is kepted to let caller check what kind of error happens. Existing caller for it are savevm, delvm and qemu-img, they are not impacted by introducing a new function bdrv_snapshot_delete_by_id_or_name(), which check the return value and do the operation again. Before this patch: For qcow2, it search id first then name to find the one to delete. For rbd, it search name. For sheepdog, it does nothing. After this patch: For qcow2, logic is the same by call it twice in caller. For rbd, it always fails in delete with id, but still search for name in second try, no change to user. Some code for *errp is based on Pavel's patch. Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> Signed-off-by: Pavel Hrdina <phrdina@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-12qcow2: Save refcount order in BDRVQcowStateMax Reitz1-0/+1
Save the image refcount order in BDRVQcowState. This will be relevant for future code supporting different refcount orders than four and also for code that needs to verify a certain refcount order for an opened image. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-12qcow2-cluster: Expand zero clustersMax Reitz1-0/+5
Add functionality for expanding zero clusters. This is necessary for downgrading the image version to one without zero cluster support. For non-backed images, this function may also just discard zero clusters instead of truly expanding them. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-12qcow2-cache: Empty cacheMax Reitz1-0/+2
Add a function for emptying a cache, i.e., flushing it and marking all elements invalid. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-12qcow2: Discard VM state in active L1 after creating snapshotKevin Wolf1-0/+5
During savevm, the VM state is written to the active L1 of the image and then a snapshot is taken. After that, the VM state isn't needed any more in the active L1 and should be discarded. This is implemented by this patch. The impact of not discarding the VM state is that a snapshot can never become smaller than any previous snapshot (because it would be padded with old VM state), and more importantly that future savevm operations cause unnecessary COWs (with associated flushes), which makes subsequent snapshots much slower. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2013-09-12qcow2: Pass discard type to qcow2_discard_clusters()Kevin Wolf1-1/+1
The function will be used internally instead of only being called for guest discard requests. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2013-08-30qcow2-refcount: Repair OFLAG_COPIED errorsMax Reitz1-0/+1
Since the OFLAG_COPIED checks are now executed after the refcounts have been repaired (if repairing), it is safe to assume that they are correct but the OFLAG_COPIED flag may be not. Therefore, if its value differs from what it should be (considering the according refcount), that discrepancy can be repaired by correctly setting (or clearing that flag. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-08-30qcow2: Metadata overlap checksMax Reitz1-0/+39
Two new functions are added; the first one checks a given range in the image file for overlaps with metadata (main header, L1 tables, L2 tables, refcount table and blocks). The second one should be used immediately before writing to the image file as it calls the first function and, upon collision, marks the image as corrupt and makes the BDS unusable, thereby preventing further access. Both functions take a bitmask argument specifying the structures which should be checked for overlaps, making it possible to also check metadata writes against colliding with other structures. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-08-30qcow2: Add corrupt bitMax Reitz1-1/+6
This adds an incompatible bit indicating corruption to qcow2. Any image with this bit set may not be written to unless for repairing (and subsequently clearing the bit if the repair has been successful). Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-08-30block/qcow2.h: Avoid "1LL << 63" (shifts into sign bit)Peter Maydell1-3/+3
The expression "1LL << 63" tries to shift the 1 into the sign bit of a 'long long', which provokes a clang sanitizer warning: runtime error: left shift of 1 by 63 places cannot be represented in type 'long long' Use "1ULL << 63" as the definition of QCOW_OFLAG_COPIED instead to avoid this. For consistency, we also update the other QCOW_OFLAG definitions to use the ULL suffix rather than LL, though only the shift by 63 is undefined behaviour. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-07-26qcow2: Use dashes instead of underscores in optionsKevin Wolf1-4/+4
This is what QMP wants to use. The options haven't been enabled in any release yet, so we're still free to change them. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2013-06-24qcow2: Batch discardsKevin Wolf1-0/+11
This optimises the discard operation for freed clusters by batching discard requests (both snapshot deletion and bdrv_discard end up updating the refcounts cluster by cluster). Note that we don't discard asynchronously, but keep s->lock held. This is to avoid that a freed cluster is reallocated and written to while the discard is still in flight. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-06-24qcow2: Options to enable discard for freed clustersKevin Wolf1-0/+5
Deleted snapshots are discarded in the image file by default, discard requests take their default from the -drive discard=... option and other places that free clusters must always be enabled explicitly. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-06-24qcow2: Add refcount update reason to all callersKevin Wolf1-3/+13
This adds a refcount update reason to all callers of update_refcounts(), so that a follow-up patch can use this information to decide whether clusters that reach a refcount of 0 should be discarded in the image file. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-05-14qcow2: Catch some L1 table index overflowsKevin Wolf1-2/+3
This catches the situation that is described in the bug report at https://bugs.launchpad.net/qemu/+bug/865518 and goes like this: $ qemu-img create -f qcow2 huge.qcow2 $((1024*1024))T Formatting 'huge.qcow2', fmt=qcow2 size=1152921504606846976 encryption=off cluster_size=65536 lazy_refcounts=off $ qemu-io /tmp/huge.qcow2 -c "write $((1024*1024*1024*1024*1024*1024 - 1024)) 512" Segmentation fault With this patch applied the segfault will be avoided, however the case will still fail, though gracefully: $ qemu-img create -f qcow2 /tmp/huge.qcow2 $((1024*1024))T Formatting 'huge.qcow2', fmt=qcow2 size=1152921504606846976 encryption=off cluster_size=65536 lazy_refcounts=off qemu-img: The image size is too large for file format 'qcow2' Note that even long before these overflow checks kick in, you get insanely high memory usage (up to INT_MAX * sizeof(uint64_t) = 16 GB for the L1 table), so with somewhat smaller image sizes you'll probably see qemu aborting for a failed g_malloc(). If you need huge image sizes, you should increase the cluster size to the maximum of 2 MB in order to get higher limits. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-04-13aes: move aes.h from include/block to include/qemuAurelien Jarno1-1/+1
Move aes.h from include/block to include/qemu to show it can be reused by other subsystems. Cc: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@gmail.com> Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
2013-03-28qcow2: Allow requests with multiple l2metasKevin Wolf1-0/+3
Instead of expecting a single l2meta, have a list of them. This allows to still have a single I/O request for the guest data, even though multiple l2meta may be needed in order to describe both a COW overwrite and a new cluster allocation (typical sequential write case). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
generated by cgit v1.1 at 2024-12-28 17:37:49 +0000