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path: root/block/qcow2.c
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2017-07-25qcow: fix memory leaks related to encryptionDaniel P. Berrange
Fix leak of the 'encryptopts' string, which was mistakenly declared const. Fix leak of QemuOpts entry which should not have been deleted from the opts array. Reported by: coverity Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-id: 20170714103105.5781-1-berrange@redhat.com Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-24qcow2: Fix sector calculation in qcow2_measure()Eric Blake
We used MAX() instead of the intended MIN() when computing how many sectors to view in the current loop iteration of qcow2_measure(), and passed in a value of INT_MAX sectors instead of our more usual limit of BDRV_REQUEST_MAX_SECTORS (the latter avoids 32-bit overflow on conversion to bytes). For small files, the bug is harmless: bdrv_get_block_status_above() clamps its *pnum answer to the BDS size, regardless of any insanely larger input request. However, for any file at least 2T in size, we can very easily end up going into an infinite loop (the maximum of 0x100000000 sectors and INT_MAX is a 64-bit quantity, which becomes 0 when assigned to int; once nb_sectors is 0, we never make progress). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-07-17qcow2: call CoQueue APIs under CoMutexPaolo Bonzini
Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20170629132749.997-2-pbonzini@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
2017-07-11block/qcow2: falloc/full preallocating growthMax Reitz
Implement the preallocation modes falloc and full for growing qcow2 images. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20170613202107.10125-15-mreitz@redhat.com Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11block/qcow2: Add qcow2_refcount_area()Max Reitz
This function creates a collection of self-describing refcount structures (including a new refcount table) at the end of a qcow2 image file. Optionally, these structures can also describe a number of additional clusters beyond themselves; this will be important for preallocated truncation, which will place the data clusters and L2 tables there. For now, we can use this function to replace the part of alloc_refcount_block() that grows the refcount table (from which it is actually derived). Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20170613202107.10125-13-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11block/qcow2: Metadata preallocation for truncateMax Reitz
We can support PREALLOC_MODE_METADATA by invoking preallocate() in qcow2_truncate(). Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20170613202107.10125-12-mreitz@redhat.com Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11block/qcow2: Lock s->lock in preallocate()Max Reitz
preallocate() is and will be called only from places that do not otherwise need to lock s->lock: Currently that is qcow2_create2(), as of a future patch it will be called from qcow2_truncate(), too. It therefore makes sense to move locking that mutex into preallocate() itself. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20170613202107.10125-11-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11block/qcow2: Generalize preallocate()Max Reitz
This patch adds two new parameters to the preallocate() function so we will be able to use it not just for preallocating a new image but also for preallocated image growth. The offset parameter allows the caller to specify a virtual offset from which to start preallocating. For newly created images this is always 0, but for preallocating growth this will be the old image length. The new_length parameter specifies the supposed new length of the image (basically the "end offset" for preallocation). During image truncation, bdrv_getlength() will return the old image length so we cannot rely on its return value then. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20170613202107.10125-10-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11block: Add PreallocMode to blk_truncate()Max Reitz
blk_truncate() itself will pass that value to bdrv_truncate(), and all callers of blk_truncate() just set the parameter to PREALLOC_MODE_OFF for now. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20170613202107.10125-4-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11block: Add PreallocMode to bdrv_truncate()Max Reitz
For block drivers that just pass a truncate request to the underlying protocol, we can now pass the preallocation mode instead of aborting if it is not PREALLOC_MODE_OFF. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20170613202107.10125-3-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11block: Add PreallocMode to BD.bdrv_truncate()Max Reitz
Add a PreallocMode parameter to the bdrv_truncate() function implemented by each block driver. Currently, we always pass PREALLOC_MODE_OFF and no driver accepts anything else. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20170613202107.10125-2-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11qcow2: add bdrv_measure() supportStefan Hajnoczi
Use qcow2_calc_prealloc_size() to get the required file size. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 20170705125738.8777-7-stefanha@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11qcow2: extract image creation option parsingStefan Hajnoczi
The image creation options parsed by qcow2_create() are also needed to implement .bdrv_measure(). Extract the parsing code, including input validation. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 20170705125738.8777-6-stefanha@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11qcow2: make refcount size calculation conservativeStefan Hajnoczi
The refcount metadata size calculation is inaccurate and can produce numbers that are too small. This is bad because we should calculate a conservative number - one that is guaranteed to be large enough. This patch switches the approach to a fixed point calculation because the existing equation is hard to solve when inaccuracies are taken care of. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 20170705125738.8777-5-stefanha@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11qcow2: extract preallocation calculation functionStefan Hajnoczi
Calculating the preallocated image size will be needed to implement .bdrv_measure(). Extract the code out into a separate function. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 20170705125738.8777-4-stefanha@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11qcow2: add .bdrv_remove_persistent_dirty_bitmapVladimir Sementsov-Ogievskiy
Realize .bdrv_remove_persistent_dirty_bitmap interface. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 20170628120530.31251-29-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11qcow2: add .bdrv_can_store_new_dirty_bitmapVladimir Sementsov-Ogievskiy
Realize .bdrv_can_store_new_dirty_bitmap interface. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: John Snow <jsnow@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170628120530.31251-23-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11qcow2: store bitmaps on reopening image as read-onlyVladimir Sementsov-Ogievskiy
Store bitmaps and mark them read-only on reopening image as read-only. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170628120530.31251-21-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11qcow2: add persistent dirty bitmaps supportVladimir Sementsov-Ogievskiy
Store persistent dirty bitmaps in qcow2 image. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170628120530.31251-20-vsementsov@virtuozzo.com [mreitz: Always assign ret in store_bitmap() in case of an error] Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11qcow2: support .bdrv_reopen_bitmaps_rwVladimir Sementsov-Ogievskiy
Realize bdrv_reopen_bitmaps_rw interface. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: John Snow <jsnow@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170628120530.31251-15-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11qcow2: autoloading dirty bitmapsVladimir Sementsov-Ogievskiy
Auto loading bitmaps are bitmaps in Qcow2, with the AUTO flag set. They are loaded when the image is opened and become BdrvDirtyBitmaps for the corresponding drive. Extra data in bitmaps is not supported for now. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 20170628120530.31251-12-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11qcow2: add bitmaps extensionVladimir Sementsov-Ogievskiy
Add bitmap extension as specified in docs/specs/qcow2.txt. For now, just mirror extension header into Qcow2 state and check constraints. Also, calculate refcounts for qcow2 bitmaps, to not break qemu-img check. For now, disable image resize if it has bitmaps. It will be fixed later. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 20170628120530.31251-9-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11qcow2: report encryption specific image informationDaniel P. Berrange
Currently 'qemu-img info' reports a simple "encrypted: yes" field. This is not very useful now that qcow2 can support multiple encryption formats. Users want to know which format is in use and some data related to it. Wire up usage of the qcrypto_block_get_info() method so that 'qemu-img info' can report about the encryption format and parameters in use $ qemu-img create \ --object secret,id=sec0,data=123456 \ -o encrypt.format=luks,encrypt.key-secret=sec0 \ -f qcow2 demo.qcow2 1G Formatting 'demo.qcow2', fmt=qcow2 size=1073741824 \ encryption=off encrypt.format=luks encrypt.key-secret=sec0 \ cluster_size=65536 lazy_refcounts=off refcount_bits=16 $ qemu-img info demo.qcow2 image: demo.qcow2 file format: qcow2 virtual size: 1.0G (1073741824 bytes) disk size: 480K encrypted: yes cluster_size: 65536 Format specific information: compat: 1.1 lazy refcounts: false refcount bits: 16 encrypt: ivgen alg: plain64 hash alg: sha256 cipher alg: aes-256 uuid: 3fa930c4-58c8-4ef7-b3c5-314bb5af21f3 format: luks cipher mode: xts slots: [0]: active: true iters: 1839058 key offset: 4096 stripes: 4000 [1]: active: false key offset: 262144 [2]: active: false key offset: 520192 [3]: active: false key offset: 778240 [4]: active: false key offset: 1036288 [5]: active: false key offset: 1294336 [6]: active: false key offset: 1552384 [7]: active: false key offset: 1810432 payload offset: 2068480 master key iters: 438487 corrupt: false With the legacy "AES" encryption we just report the format name $ qemu-img create \ --object secret,id=sec0,data=123456 \ -o encrypt.format=aes,encrypt.key-secret=sec0 \ -f qcow2 demo.qcow2 1G Formatting 'demo.qcow2', fmt=qcow2 size=1073741824 \ encryption=off encrypt.format=aes encrypt.key-secret=sec0 \ cluster_size=65536 lazy_refcounts=off refcount_bits=16 $ ./qemu-img info demo.qcow2 image: demo.qcow2 file format: qcow2 virtual size: 1.0G (1073741824 bytes) disk size: 196K encrypted: yes cluster_size: 65536 Format specific information: compat: 1.1 lazy refcounts: false refcount bits: 16 encrypt: format: aes corrupt: false Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-id: 20170623162419.26068-20-berrange@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11block: pass option prefix down to crypto layerDaniel P. Berrange
While the crypto layer uses a fixed option name "key-secret", the upper block layer may have a prefix on the options. e.g. "encrypt.key-secret", in order to avoid clashes between crypto option names & other block option names. To ensure the crypto layer can report accurate error messages, we must tell it what option name prefix was used. Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-id: 20170623162419.26068-19-berrange@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11block: remove all encryption handling APIsDaniel P. Berrange
Now that all encryption keys must be provided upfront via the QCryptoSecret API and associated block driver properties there is no need for any explicit encryption handling APIs in the block layer. Encryption can be handled transparently within the block driver. We only retain an API for querying whether an image is encrypted or not, since that is a potentially useful piece of metadata to report to the user. Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-id: 20170623162419.26068-18-berrange@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11qcow2: add support for LUKS encryption formatDaniel P. Berrange
This adds support for using LUKS as an encryption format with the qcow2 file, using the new encrypt.format parameter to request "luks" format. e.g. # qemu-img create --object secret,data=123456,id=sec0 \ -f qcow2 -o encrypt.format=luks,encrypt.key-secret=sec0 \ test.qcow2 10G The legacy "encryption=on" parameter still results in creation of the old qcow2 AES format (and is equivalent to the new 'encryption-format=aes'). e.g. the following are equivalent: # qemu-img create --object secret,data=123456,id=sec0 \ -f qcow2 -o encryption=on,encrypt.key-secret=sec0 \ test.qcow2 10G # qemu-img create --object secret,data=123456,id=sec0 \ -f qcow2 -o encryption-format=aes,encrypt.key-secret=sec0 \ test.qcow2 10G With the LUKS format it is necessary to store the LUKS partition header and key material in the QCow2 file. This data can be many MB in size, so cannot go into the QCow2 header region directly. Thus the spec defines a FDE (Full Disk Encryption) header extension that specifies the offset of a set of clusters to hold the FDE headers, as well as the length of that region. The LUKS header is thus stored in these extra allocated clusters before the main image payload. Aside from all the cryptographic differences implied by use of the LUKS format, there is one further key difference between the use of legacy AES and LUKS encryption in qcow2. For LUKS, the initialiazation vectors are generated using the host physical sector as the input, rather than the guest virtual sector. This guarantees unique initialization vectors for all sectors when qcow2 internal snapshots are used, thus giving stronger protection against watermarking attacks. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-id: 20170623162419.26068-14-berrange@redhat.com Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11qcow2: convert QCow2 to use QCryptoBlock for encryptionDaniel P. Berrange
This converts the qcow2 driver to make use of the QCryptoBlock APIs for encrypting image content, using the legacy QCow2 AES scheme. With this change it is now required to use the QCryptoSecret object for providing passwords, instead of the current block password APIs / interactive prompting. $QEMU \ -object secret,id=sec0,file=/home/berrange/encrypted.pw \ -drive file=/home/berrange/encrypted.qcow2,encrypt.key-secret=sec0 The test 087 could be simplified since there is no longer a difference in behaviour when using blockdev_add with encrypted images for the running vs stopped CPU state. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-id: 20170623162419.26068-12-berrange@redhat.com Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11qcow2: make qcow2_encrypt_sectors encrypt in placeDaniel P. Berrange
Instead of requiring separate input/output buffers for encrypting data, change qcow2_encrypt_sectors() to assume use of a single buffer, encrypting in place. The current callers all used the same buffer for input/output already. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-id: 20170623162419.26068-11-berrange@redhat.com Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11block: deprecate "encryption=on" in favor of "encrypt.format=aes"Daniel P. Berrange
Historically the qcow & qcow2 image formats supported a property "encryption=on" to enable their built-in AES encryption. We'll soon be supporting LUKS for qcow2, so need a more general purpose way to enable encryption, with a choice of formats. This introduces an "encrypt.format" option, which will later be joined by a number of other "encrypt.XXX" options. The use of a "encrypt." prefix instead of "encrypt-" is done to facilitate mapping to a nested QAPI schema at later date. e.g. the preferred syntax is now qemu-img create -f qcow2 -o encrypt.format=aes demo.qcow2 Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-id: 20170623162419.26068-8-berrange@redhat.com Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-06-26block: change variable names in BlockDriverStateManos Pitsidianakis
Change the 'int count' parameter in *pwrite_zeros, *pdiscard related functions (and some others) to 'int bytes', as they both refer to bytes. This helps with code legibility. Signed-off-by: Manos Pitsidianakis <el13635@mail.ntua.gr> Message-id: 20170609101808.13506-1-el13635@mail.ntua.gr Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-06-26qcow2: Use offset_into_cluster() and offset_to_l2_index()Alberto Garcia
We already have functions for doing these calculations, so let's use them instead of doing everything by hand. This makes the code a bit more readable. Signed-off-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-06-26qcow2: Merge the writing of the COW regions with the guest dataAlberto Garcia
If the guest tries to write data that results on the allocation of a new cluster, instead of writing the guest data first and then the data from the COW regions, write everything together using one single I/O operation. This can improve the write performance by 25% or more, depending on several factors such as the media type, the cluster size and the I/O request size. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-05-29qcow2: remove extra local_error variableAlberto Garcia
Commit d7086422b1c1e75e320519cfe26176db6ec97a37 added a local_err variable global to the qcow2_amend_options() function, so there's no need to have this other one. Signed-off-by: Alberto Garcia <berto@igalia.com> Message-id: 20170511150337.21470-1-berto@igalia.com Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-11qcow2: Discard/zero clusters by byte countEric Blake
Passing a byte offset, but sector count, when we ultimately want to operate on cluster granularity, is madness. Clean up the external interfaces to take both offset and count as bytes, while still keeping the assertion added previously that the caller must align the values to a cluster. Then rename things to make sure backports don't get confused by changed units: instead of qcow2_discard_clusters() and qcow2_zero_clusters(), we now have qcow2_cluster_discard() and qcow2_cluster_zeroize(). The internal functions still operate on clusters at a time, and return an int for number of cleared clusters; but on an image with 2M clusters, a single L2 table holds 256k entries that each represent a 2M cluster, totalling well over INT_MAX bytes if we ever had a request for that many bytes at once. All our callers currently limit themselves to 32-bit bytes (and therefore fewer clusters), but by making this function 64-bit clean, we have one less place to clean up if we later improve the block layer to support 64-bit bytes through all operations (with the block layer auto-fragmenting on behalf of more-limited drivers), rather than the current state where some interfaces are artificially limited to INT_MAX at a time. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170507000552.20847-13-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-11qcow2: Optimize write zero of unaligned tail clusterEric Blake
We've already improved discards to operate efficiently on the tail of an unaligned qcow2 image; it's time to make a similar improvement to write zeroes. The special case is only valid at the tail cluster of a file, where we must recognize that any sectors beyond the image end would implicitly read as zero, and therefore should not penalize our logic for widening a partial cluster into writing the whole cluster as zero. However, note that for now, the special case of end-of-file is only recognized if there is no backing file, or if the backing file has the same length; that's because when the backing file is shorter than the active layer, we don't have code in place to recognize that reads of a sector unallocated at the top and beyond the backing end-of-file are implicitly zero. It's not much of a real loss, because most people don't use images that aren't cluster-aligned, or where the active layer is a different size than the backing layer (especially where the difference falls within a single cluster). Update test 154 to cover the new scenarios, using two images of intentionally differing length. While at it, fix the test to gracefully skip when run as ./check -qcow2 -o compat=0.10 154 since the older format lacks zero clusters already required earlier in the test. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170507000552.20847-11-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-11qcow2: Make distinction between zero cluster types obviousEric Blake
Treat plain zero clusters differently from allocated ones, so that we can simplify the logic of checking whether an offset is present. Do this by splitting QCOW2_CLUSTER_ZERO into two new enums, QCOW2_CLUSTER_ZERO_PLAIN and QCOW2_CLUSTER_ZERO_ALLOC. I tried to arrange the enum so that we could use 'ret <= QCOW2_CLUSTER_ZERO_PLAIN' for all unallocated types, and 'ret >= QCOW2_CLUSTER_ZERO_ALLOC' for allocated types, although I didn't actually end up taking advantage of the layout. In many cases, this leads to simpler code, by properly combining cases (sometimes, both zero types pair together, other times, plain zero is more like unallocated while allocated zero is more like normal). Signed-off-by: Eric Blake <eblake@redhat.com> Message-id: 20170507000552.20847-7-eblake@redhat.com Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-11qcow2: Fix preallocation size formulaMax Reitz
When calculating the number of reftable entries, we should actually use the number of refblocks and not (wrongly[1]) re-calculate it. [1] "Wrongly" means: Dividing the number of clusters by the number of entries per refblock and rounding down instead of up. Reported-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-05-09qobject: Use simpler QDict/QList scalar insertion macrosEric Blake
We now have macros in place to make it less verbose to add a scalar to QDict and QList, so use them. Patch created mechanically via: spatch --sp-file scripts/coccinelle/qobject.cocci \ --macro-file scripts/cocci-macro-file.h --dir . --in-place then touched up manually to fix a couple of '?:' back to original spacing, as well as avoiding a long line in monitor.c. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20170427215821.19397-7-eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2017-04-28qcow2: Allow discard of final unaligned clusterEric Blake
As mentioned in commit 0c1bd46, we ignored requests to discard the trailing cluster of an unaligned image. While discard is an advisory operation from the guest standpoint, (and we are therefore free to ignore any request), our qcow2 implementation exploits the fact that a discarded cluster reads back as 0. As long as we discard on cluster boundaries, we are fine; but that means we could observe non-zero data leaked at the tail of an unaligned image. Enhance iotest 66 to cover this case, and fix the implementation to honor a discard request on the final partial cluster. Signed-off-by: Eric Blake <eblake@redhat.com> Message-id: 20170407013709.18440-1-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-28block: Add .bdrv_truncate() error messagesMax Reitz
Add missing error messages for the block driver implementations of .bdrv_truncate(); drop the generic one from block.c's bdrv_truncate(). Since one of these changes touches a mis-indented block in block/file-posix.c, this patch fixes that coding style issue along the way. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20170328205129.15138-5-mreitz@redhat.com Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-28block: Add errp to BD.bdrv_truncate()Max Reitz
Add an Error parameter to the block drivers' bdrv_truncate() interface. If a block driver does not set this in case of an error, the generic bdrv_truncate() implementation will do so. Where it is obvious, this patch also makes some block drivers set this value. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20170328205129.15138-4-mreitz@redhat.com Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-28block: Add errp to b{lk,drv}_truncate()Max Reitz
For one thing, this allows us to drop the error message generation from qemu-img.c and blockdev.c and instead have it unified in bdrv_truncate(). Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20170328205129.15138-3-mreitz@redhat.com Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-02-28block: Add BDRV_O_RESIZE for blk_new_open()Kevin Wolf
blk_new_open() is a convenience function that processes flags rather than QDict options as a simple way to just open an image file. In order to keep it convenient in the future, it must automatically request the necessary permissions. This can easily be inferred from the flags for read and write, but we need another flag that tells us whether to get the resize permission. We can't just always request it because that means that no block jobs can run on the resulting BlockBackend (which is something that e.g. qemu-img commit wants to do), but we also can't request it never because most of the .bdrv_create() implementations call blk_truncate(). The solution is to introduce another flag that is passed by all users that want to resize the image. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Fam Zheng <famz@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2017-02-28block: Add error parameter to blk_insert_bs()Kevin Wolf
Now that blk_insert_bs() requests the BlockBackend permissions for the node it attaches to, it can fail. Instead of aborting, pass the errors to the callers. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Fam Zheng <famz@redhat.com>
2017-02-28block: Add permissions to blk_new()Kevin Wolf
We want every user to be specific about the permissions it needs, so we'll pass the initial permissions as parameters to blk_new(). A user only needs to call blk_set_perm() if it wants to change the permissions after the fact. The permissions are stored in the BlockBackend and applied whenever a BlockDriverState should be attached in blk_insert_bs(). This does not include actually choosing the right set of permissions everywhere yet. Instead, the usual FIXME comment is added to each place and will be addressed in individual patches. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Fam Zheng <famz@redhat.com>
2017-02-28block: Request child permissions in format driversKevin Wolf
This makes use of the .bdrv_child_perm() implementation for formats that we just added. All format drivers expose the permissions they actually need nows, so that they can be set accordingly and updated when parents are attached or detached. The only format not included here is raw, which was already converted with the other filter drivers. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Fam Zheng <famz@redhat.com>
2017-02-24block: Attach bs->file only during .bdrv_open()Kevin Wolf
The way that attaching bs->file worked was a bit unusual in that it was the only child that would be attached to a node which is not opened yet. Because of this, the block layer couldn't know yet which permissions the driver would eventually need. This patch moves the point where bs->file is attached to the beginning of the individual .bdrv_open() implementations, so drivers already know what they are going to do with the child. This is also more consistent with how driver-specific children work. For a moment, bdrv_open() gets its own BdrvChild to perform image probing, but instead of directly assigning this BdrvChild to the BDS, it becomes a temporary one and the node name is passed as an option to the drivers, so that they can simply use bdrv_open_child() to create another reference for their own use. This duplicated child for (the not opened yet) bs is not the final state, a follow-up patch will change the image probing code to use a BlockBackend, which is completely independent of bs. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2017-02-24block: Pass BdrvChild to bdrv_truncate()Kevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2017-02-24qcow2: Use BB for resizing in qcow2_amend_options()Kevin Wolf
In order to able to convert bdrv_truncate() to take a BdrvChild and later to correctly check the resize permission here, we need to use a BlockBackend for resizing the image. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2017-02-12qcow2: Optimize the refcount-block overlap checkAlberto Garcia
The metadata overlap checks introduced in a40f1c2add help detect corruption in the qcow2 image by verifying that data writes don't overlap with existing metadata sections. The 'refcount-block' check in particular iterates over the refcount table in order to get the addresses of all refcount blocks and check that none of them overlap with the region where we want to write. The problem with the refcount table is that since it always occupies complete clusters its size is usually very big. With the default values of cluster_size=64KB and refcount_bits=16 this table holds 8192 entries, each one of them enough to map 2GB worth of host clusters. So unless we're using images with several TB of allocated data this table is going to be mostly empty, and iterating over it is a waste of CPU. If the storage backend is fast enough this can have an effect on I/O performance. This patch keeps the index of the last used (i.e. non-zero) entry in the refcount table and updates it every time the table changes. The refcount-block overlap check then uses that index instead of reading the whole table. In my tests with a 4GB qcow2 file stored in RAM this doubles the amount of write IOPS. Signed-off-by: Alberto Garcia <berto@igalia.com> Message-id: 20170201123828.4815-1-berto@igalia.com Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
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