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2019-03-08qcow2: Support external data file in qemu-img checkKevin Wolf1-11/+30
For external data files, data clusters must be excluded from the refcount calculations. Instead, an implicit refcount of 1 is assumed for the COPIED flag. Compressed clusters and internal snapshots are incompatible with external data files, so print an error if they are in use for images with an external data file. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2019-03-08qcow2: External file I/OKevin Wolf1-9/+30
This changes the qcow2 implementation to direct all guest data I/O to s->data_file rather than bs->file, while metadata I/O still uses bs->file. At the moment, this is still always the same, but soon we'll add options to set s->data_file to an external data file. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2019-03-08qcow2: Pass bs to qcow2_get_cluster_type()Kevin Wolf1-5/+5
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2019-02-01qcow2: Assert that refcount block offsets fit in the refcount tableAlberto Garcia1-0/+3
Refcount table entries have a field to store the offset of the refcount block. The rest of the bits of the entry are currently reserved. The offset is always taken from the entry using REFT_OFFSET_MASK to ensure that we only use the bits that belong to that field. While that mask is used every time we read from the refcount table, it is never used when we write to it. Due to the other constraints of the qcow2 format QEMU can never produce refcount block offsets that don't fit in that field so any such offset when allocating a refcount block would indicate a bug in QEMU. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-11-19qcow2: Don't allow overflow during cluster allocationEric Blake1-7/+13
Our code was already checking that we did not attempt to allocate more clusters than what would fit in an INT64 (the physical maximimum if we can access a full off_t's worth of data). But this does not catch smaller limits enforced by various spots in the qcow2 image description: L1 and normal clusters of L2 are documented as having bits 63-56 reserved for other purposes, capping our maximum offset at 64PB (bit 55 is the maximum bit set). And for compressed images with 2M clusters, the cap drops the maximum offset to bit 48, or a maximum offset of 512TB. If we overflow that offset, we would write compressed data into one place, but try to decompress from another, which won't work. It's actually possible to prove that overflow can cause image corruption without this patch; I'll add the iotests separately in the next commit. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-11-12qcow2: Read outside array bounds in qcow2_pre_write_overlap_check()Liam Merwick1-8/+10
The commit for 0e4e4318eaa5 increments QCOW2_OL_MAX_BITNR but does not add an array entry for QCOW2_OL_BITMAP_DIRECTORY_BITNR to metadata_ol_names[]. As a result, an array dereference of metadata_ol_names[8] in qcow2_pre_write_overlap_check() could result in a read outside of the array bounds. Fixes: 0e4e4318eaa5 ('qcow2: add overlap check for bitmap directory') Cc: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Liam Merwick <Liam.Merwick@oracle.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 1541453919-25973-6-git-send-email-Liam.Merwick@oracle.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-07-10Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into stagingPeter Maydell1-1/+1
Block layer patches: - Copy offloading fixes for when the copy increases the image size - Temporary revert of the removal of deprecated -drive options - Fix request serialisation in the image fleecing scenario - Fix copy-on-read crash with unaligned image size - Fix another drain crash # gpg: Signature made Tue 10 Jul 2018 16:37:52 BST # gpg: using RSA key 7F09B272C88F2FD6 # gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" # Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6 * remotes/kevin/tags/for-upstream: (24 commits) block: Use common write req handling in truncate block: Fix bdrv_co_truncate overlap check block: Use common req handling in copy offloading block: Use common req handling for discard block: Fix handling of image enlarging write block: Extract common write req handling block: Use uint64_t for BdrvTrackedRequest byte fields block: Use BdrvChild to discard block: Add copy offloading trace points block: Prefix file driver trace points with "file_" Revert "block: Remove deprecated -drive geometry options" Revert "block: Remove deprecated -drive option addr" Revert "block: Remove deprecated -drive option serial" Revert "block: Remove dead deprecation warning code" block/blklogwrites: Make sure the log sector size is not too small qapi/block-core.json: Add missing documentation for blklogwrites log-append option block/backup: fix fleecing scheme: use serialized writes block: add BDRV_REQ_SERIALISING flag block: split flags in copy_range block/io: fix copy_range ... Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-07-10block: Use BdrvChild to discardFam Zheng1-1/+1
Other I/O functions are already using a BdrvChild pointer in the API, so make discard do the same. It makes it possible to initiate the same permission checks before doing I/O, and much easier to share the helper functions for this, which will be added and used by write, truncate and copy range paths. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-07-09qcow2: add overlap check for bitmap directoryVladimir Sementsov-Ogievskiy1-0/+10
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20180705151515.779173-1-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-06-11qcow2: Repair OFLAG_COPIED when fixing leaksMax Reitz1-8/+17
Repairing OFLAG_COPIED is usually safe because it is done after the refcounts have been repaired. Therefore, it we did not find anyone else referencing a data or L2 cluster, it makes no sense to not set OFLAG_COPIED -- and the other direction (clearing OFLAG_COPIED) is always safe, anyway, it may just induce leaks. Furthermore, if OFLAG_COPIED is actually consistent with a wrong (leaky) refcount, we will decrement the refcount with -r leaks, but OFLAG_COPIED will then be wrong. qemu-img check should not produce images that are more corrupted afterwards then they were before. Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1527085 Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20180509200059.31125-2-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-31block: use local path for local headersMichael S. Tsirkin1-1/+1
When pulling in headers that are in the same directory as the C file (as opposed to one in include/), we should use its relative path, without a directory. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2018-05-15Fix error message about compressed clusters with OFLAG_COPIEDAlberto Garcia1-2/+2
Compressed clusters are not supposed to have the COPIED bit set. "qemu-img check" detects that and prints an error message reporting the number of the affected host cluster. This doesn't make much sense because compressed clusters are not aligned to host clusters, so it would be better to report the offset instead. Plus, the calculation is wrong and it uses the raw L2 entry as if it was simply an offset. This patch fixes the error message and reports the offset of the compressed cluster. Signed-off-by: Alberto Garcia <berto@igalia.com> Message-id: 0f687957feb72e80c740403191a47e607c2463fe.1523376013.git.berto@igalia.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-03-26qcow2: Reset free_cluster_index when allocating a new refcount blockAlberto Garcia1-0/+7
When we try to allocate new clusters we first look for available ones starting from s->free_cluster_index and once we find them we increase their reference counts. Before we get to call update_refcount() to do this last step s->free_cluster_index is already pointing to the next cluster after the ones we are trying to allocate. During update_refcount() it may happen however that we also need to allocate a new refcount block in order to store the refcounts of these new clusters (and to complicate things further that may also require us to grow the refcount table). After all this we don't know if the clusters that we originally tried to allocate are still available, so we return -EAGAIN to ask the caller to restart the search for free clusters. This is what can happen in a common scenario: 1) We want to allocate a new cluster and we see that cluster N is free. 2) We try to increase N's refcount but all refcount blocks are full, so we allocate a new one at N+1 (where s->free_cluster_index was pointing at). 3) Once we're done we return -EAGAIN to look again for a free cluster, but now s->free_cluster_index points at N+2, so that's the one we allocate. Cluster N remains unallocated and we have a hole in the qcow2 file. This can be reproduced easily: qemu-img create -f qcow2 -o cluster_size=512 hd.qcow2 1M qemu-io -c 'write 0 124k' hd.qcow2 After this the image has 132608 bytes (256 clusters), and the refcount block is full. If we write 512 more bytes it should allocate two new clusters: the data cluster itself and a new refcount block. qemu-io -c 'write 124k 512' hd.qcow2 However the image has now three new clusters (259 in total), and the first one of them is empty (and unallocated): dd if=hd.qcow2 bs=512c skip=256 count=1 | hexdump -C If we write larger amounts of data in the last step instead of the 512 bytes used in this example we can create larger holes in the qcow2 file. What this patch does is reset s->free_cluster_index to its previous value when alloc_refcount_block() returns -EAGAIN. This way the caller will try to allocate again the original clusters if they are still free. The output of iotest 026 also needs to be updated because now that images have no holes some tests fail at a different point and the number of leaked clusters is different. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-03-09qcow2: Make qemu-img check detect corrupted L1 tables in snapshotsAlberto Garcia1-0/+14
'qemu-img check' cannot detect if a snapshot's L1 table is corrupted. This patch checks the table's offset and size and reports corruption if the values are not valid. This patch doesn't add code to fix that corruption yet, only to detect and report it. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-03-09qcow2: Check snapshot L1 tables in qcow2_check_metadata_overlap()Alberto Garcia1-1/+9
The inactive-l2 overlap check iterates uses the L1 tables from all snapshots, but it does not validate them first. We now have a function to take care of this, so let's use it. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-03-09qcow2: introduce qcow2_write_caches and qcow2_flush_cachesPaolo Bonzini1-0/+28
They will be used to avoid recursively taking s->lock during bdrv_open or bdrv_check. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <1516279431-30424-7-git-send-email-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-03-02qcow2: Replace align_offset() with ROUND_UP()Alberto Garcia1-2/+2
The align_offset() function is equivalent to the ROUND_UP() macro so there's no need to use the former. The ROUND_UP() name is also a bit more explicit. This patch uses ROUND_UP() instead of the slower QEMU_ALIGN_UP() because align_offset() already requires that the second parameter is a power of two. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-id: 20180215131008.5153-1-berto@igalia.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-02-13qcow2: Update qcow2_update_snapshot_refcount() to support L2 slicesAlberto Garcia1-14/+18
qcow2_update_snapshot_refcount() increases the refcount of all clusters of a given snapshot. In order to do that it needs to load all its L2 tables and iterate over their entries. Since we'll be loading L2 slices instead of full tables we need to add an extra loop that iterates over all slices of each L2 table. This function doesn't need any additional changes so apart from that this patch simply updates the variable name from l2_table to l2_slice. Signed-off-by: Alberto Garcia <berto@igalia.com> Message-id: 5f4db199b9637f4833b58487135124d70add8cf0.1517840877.git.berto@igalia.com Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-02-13qcow2: Prepare qcow2_update_snapshot_refcount() for adding L2 slice supportAlberto Garcia1-69/+75
Adding support for L2 slices to qcow2_update_snapshot_refcount() needs (among other things) an extra loop that iterates over all slices of each L2 table. Putting all changes in one patch would make it hard to read because all semantic changes would be mixed with pure indentation changes. To make things easier this patch simply creates a new block and changes the indentation of all lines of code inside it. Thus, all modifications in this patch are cosmetic. There are no semantic changes and no variables are renamed yet. The next patch will take care of that. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 8ffaa5e55bd51121f80e498f4045b64902a94293.1517840877.git.berto@igalia.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-02-13qcow2: Remove BDS parameter from qcow2_cache_is_table_offset()Alberto Garcia1-3/+3
This function was only using the BlockDriverState parameter to pass it to qcow2_cache_get_table_addr(). This is no longer necessary so this parameter can be removed. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: eb0ed90affcf302e5a954bafb5931b5215483d3a.1517840877.git.berto@igalia.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-02-13qcow2: Remove BDS parameter from qcow2_cache_discard()Alberto Garcia1-3/+3
This function was only using the BlockDriverState parameter to pass it to qcow2_cache_get_table_idx() and qcow2_cache_table_release(). This is no longer necessary so this parameter can be removed. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 9724f7e38e763ad3be32627c6b7fe8df9edb1476.1517840877.git.berto@igalia.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-02-13qcow2: Remove BDS parameter from qcow2_cache_put()Alberto Garcia1-15/+15
This function was only using the BlockDriverState parameter to pass it to qcow2_cache_get_table_idx(). This is no longer necessary so this parameter can be removed. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 6f98155489054a457563da77cdad1a66ebb3e896.1517840876.git.berto@igalia.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-02-13qcow2: Remove BDS parameter from qcow2_cache_entry_mark_dirty()Alberto Garcia1-8/+6
This function was only using the BlockDriverState parameter to pass it to qcow2_cache_get_table_idx(). This is no longer necessary so this parameter can be removed. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 5c40516a91782b083c1428b7b6a41bb9e2679bfb.1517840876.git.berto@igalia.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-01-23qcow2: Repair unaligned preallocated zero clustersMax Reitz1-12/+58
We can easily repair unaligned preallocated zero clusters by discarding them, so why not do it? Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20171110203759.14018-2-mreitz@redhat.com Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-11-17qcow2: Add bounds check to get_refblock_offset()Max Reitz1-1/+25
Reported-by: R. Nageswara Sastry <nasastry@in.ibm.com> Buglink: https://bugs.launchpad.net/qemu/+bug/1728661 Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20171110203111.7666-5-mreitz@redhat.com Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-11-14qcow2: Prevent allocating compressed clusters at offset 0Alberto Garcia1-0/+7
If the refcount data is corrupted then we can end up trying to allocate a new compressed cluster at offset 0 in the image, triggering an assertion in qcow2_alloc_bytes() that would crash QEMU: qcow2_alloc_bytes: Assertion `offset' failed. This patch adds an explicit check for this scenario and a new test case. Signed-off-by: Alberto Garcia <berto@igalia.com> Message-id: fb53467cf48e95ff3330def1cf1003a5b862b7d9.1509718618.git.berto@igalia.com Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-11-14qcow2: Prevent allocating refcount blocks at offset 0Alberto Garcia1-0/+7
Each entry in the qcow2 cache contains an offset field indicating the location of the data in the qcow2 image. If the offset is 0 then it means that the entry contains no data and is available to be used when needed. Because of that it is not possible to store in the cache the first cluster of the qcow2 image (offset = 0). This is not a problem because that cluster always contains the qcow2 header and we're not using this cache for that. However, if the qcow2 image is corrupted it can happen that we try to allocate a new refcount block at offset 0, triggering this assertion and crashing QEMU: qcow2_cache_entry_mark_dirty: Assertion `c->entries[i].offset != 0' failed This patch adds an explicit check for this scenario and a new test case. This problem was originally reported here: https://bugs.launchpad.net/qemu/+bug/1728615 Reported-by: R.Nageswara Sastry <nasastry@in.ibm.com> Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 92a2fadd10d58b423f269c1d1a309af161cdc73f.1509718618.git.berto@igalia.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-10-06qcow2: truncate the tail of the image file after shrinking the imagePavel Butsykin1-0/+22
Now after shrinking the image, at the end of the image file, there might be a tail that probably will never be used. So we can find the last used cluster and cut the tail. Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 20170929121613.25997-3-pbutsykin@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-09-26qcow2: add shrink image supportPavel Butsykin1-0/+120
This patch add shrinking of the image file for qcow2. As a result, this allows us to reduce the virtual image size and free up space on the disk without copying the image. Image can be fragmented and shrink is done by punching holes in the image file. Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 20170918124230.8152-4-pbutsykin@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-09-26qcow2: add qcow2_cache_discardPavel Butsykin1-2/+18
Whenever l2/refcount table clusters are discarded from the file we can automatically drop unnecessary content of the cache tables. This reduces the chance of eviction useful cache data and eliminates inconsistent data in the cache with the data in the file. Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 20170918124230.8152-3-pbutsykin@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-31qcow2: fix null pointer dereferencePhilippe Mathieu-Daudé1-2/+2
It seems this assert() was somehow misplaced. block/qcow2-refcount.c:2193:42: warning: Array access (from variable 'on_disk_reftable') results in a null pointer dereference on_disk_reftable[refblock_index] = refblock_offset; ~~~~~~~~~~~~~~~~ ^ Reported-by: Clang Static Analyzer Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2017-07-11block/qcow2: falloc/full preallocating growthMax Reitz1-8/+4
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: Rename "fail_block" to just "fail"Max Reitz1-7/+7
Now alloc_refcount_block() only contains a single fail label, so it makes more sense to just name it "fail" instead of "fail_block". Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20170613202107.10125-14-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11block/qcow2: Add qcow2_refcount_area()Max Reitz1-84/+183
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: Add PreallocMode to bdrv_truncate()Max Reitz1-1/+1
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>
2017-07-11qcow2: add bitmaps extensionVladimir Sementsov-Ogievskiy1-0/+6
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-refcount: rename inc_refcounts() and make it publicVladimir Sementsov-Ogievskiy1-28/+31
This is needed for the following patch, which will introduce refcounts checking for qcow2 bitmaps. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 20170628120530.31251-8-vsementsov@virtuozzo.com [mreitz: s/inc_refcounts/qcow2_inc_refcounts_imrt/ in one more (new) place] Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11qcow2: add support for LUKS encryption formatDaniel P. Berrange1-0/+10
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>
2017-05-11qcow2: Make distinction between zero cluster types obviousEric Blake1-26/+18
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: Name typedef for cluster typeEric Blake1-1/+1
Although it doesn't add all that much type safety (this is C, after all), it does add a bit of legibility to use the name QCow2ClusterType instead of a plain int. In particular, qcow2_get_cluster_offset() has an overloaded return type; a QCow2ClusterType on success, and -errno on failure; keeping the cluster type in a separate variable makes it slightly easier for the next patch to make further computations based on the type. Suggested-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com> Message-id: 20170507000552.20847-6-eblake@redhat.com [mreitz: Use the new type in two more places (one of them pulled from the next patch)] Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-11qcow2: Use consistent switch indentationEric Blake1-42/+42
Fix a couple of inconsistent indentations, before an upcoming patch further tweaks the switch statements. (best viewed with 'git diff -b'). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170507000552.20847-3-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-11qcow2: Nicer variable names in qcow2_update_snapshot_refcount()Eric Blake1-20/+22
In order to keep checkpatch happy when the next patch changes indentation, we first have to shorten some long lines. The easiest approach is to use a new variable in place of 'offset & L2E_OFFSET_MASK', except that 'offset' is the best name for that variable. Change '[old_]offset' to '[old_]entry' to make room. While touching things, also fix checkpatch warnings about unusual 'for' statements. Suggested by Max Reitz <mreitz@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com> Message-id: 20170507000552.20847-2-eblake@redhat.com Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-28block: Add errp to b{lk,drv}_truncate()Max Reitz1-1/+4
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>
2017-02-24block: Pass BdrvChild to bdrv_truncate()Kevin Wolf1-1/+1
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2017-02-12qcow2: Optimize the refcount-block overlap checkAlberto Garcia1-1/+23
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>
2016-07-20block: Convert bdrv_discard() to byte-basedEric Blake1-3/+1
Another step towards byte-based interfaces everywhere. Replace the sector-based bdrv_discard() with a new byte-based bdrv_pdiscard(), which silently ignores any unaligned head or tail. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 1468624988-423-3-git-send-email-eblake@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-05block/qcow2: Don't use cpu_to_*w()Peter Maydell1-6/+5
Don't use the cpu_to_*w() functions, which we are trying to deprecate. Instead either just use cpu_to_*() to do the byteswap, or use st*_be_p() if we need to do the store somewhere other than to a variable that's already the correct type. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1466093177-17890-1-git-send-email-peter.maydell@linaro.org Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2016-07-05block: Convert bdrv_pwrite(v/_sync) to BdrvChildKevin Wolf1-11/+11
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-05block: Convert bdrv_pread(v) to BdrvChildKevin Wolf1-6/+6
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-05block: Convert bdrv_write() to BdrvChildKevin Wolf1-1/+1
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
generated by cgit v1.1 at 2024-12-28 02:44:59 +0000