summaryrefslogtreecommitdiff
path: root/block/qcow2-refcount.c
AgeCommit message (Collapse)AuthorFilesLines
2013-09-12qcow2-cluster: Expand zero clustersMax Reitz1-14/+15
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>
2013-09-02qcow2-refcount: Repair shared refcount blocksMax Reitz1-2/+146
If the refcount of a refcount block is greater than one, we can at least try to repair that problem by duplicating the affected block. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-08-30qcow2-refcount: Repair OFLAG_COPIED errorsMax Reitz1-6/+52
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-refcount: Move OFLAG_COPIED checksMax Reitz1-33/+82
Move the OFLAG_COPIED checks out of check_refcounts_l1 and check_refcounts_l2 and after the actual refcount checks/fixes (since the refcounts might actually change there). Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-08-30qcow2: Metadata overlap checksMax Reitz1-0/+172
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-refcount: Snapshot update for zero clustersMax Reitz1-17/+35
Account for all cluster types in qcow2_update_snapshot_refcounts; this prevents this function from updating the refcount of unallocated zero clusters which effectively led to wrong adjustments of the refcount of cluster 0 (the main qcow2 header). This in turn resulted in images with (unallocated) zero clusters having a cluster 0 refcount greater than one after creating a snapshot. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24qcow2: Batch discardsKevin Wolf1-3/+79
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 Wolf1-21/+34
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>
2013-04-05qcow2: Fix L1 write error handling in qcow2_update_snapshot_refcountKevin Wolf1-6/+8
It ignored the error code, and at least the 'goto fail' is obvious nonsense as it creates an endless loop (if the next attempt doesn't magically succeed) and leaves the in-memory L1 table in big-endian instead of converting it back. In error cases, there's no point in writing an updated L1 table, so skip this part for them. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-04-05qcow2: Return real error in qcow2_update_snapshot_refcountKevin Wolf1-6/+5
This fixes the error message triggered by the following script: cat > /tmp/blkdebug.cfg <<EOF [inject-error] event = "cluster_free" errno = "28" immediately = "off" EOF $qemu_img create -f qcow2 test.qcow2 10G $qemu_img snapshot -c snap test.qcow2 $qemu_img snapshot -d snap blkdebug:/tmp/blkdebug.cfg:test.qcow2 Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-03-28qcow2: Fix "total clusters" number in bdrv_checkKevin Wolf1-1/+3
This should be based on the virtual disk size, not on the size of the image. Interesting observation: With some VM state stored in the image file, percentages higher than 100% are possible, even though snapshots themselves are ignored. This is a qcow2 bug to be fixed another day: The VM state should be discarded in the active L2 tables after completing the snapshot creation. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-03-15qcow2: drop unnecessary flush in qcow2_update_snapshot_refcount()Stefan Hajnoczi1-4/+0
We already flush when the function completes. There is no need to flush after every compressed cluster. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-03-15qcow2: drop flush in update_cluster_refcount()Stefan Hajnoczi1-2/+0
The update_cluster_refcount() function increments/decrements a cluster's refcount and then returns the new refcount value. There is no need to flush since both update_cluster_refcount() callers already take care of this: 1. qcow2_alloc_bytes() calls update_cluster_refcount() when compressed sectors will be appended to an existing cluster with enough free space. qcow2_alloc_bytes() already flushes so there is no need to do so in update_cluster_refcount(). 2. qcow2_update_snapshot_refcount() sets a cache dependency on refcounts if it needs to update L2 entries. It also flushes before completing. Removing this flush significantly speeds up qcow2 snapshot creation: $ qemu-img create -f qcow2 test.qcow2 -o size=50G,preallocation=metadata $ time qemu-img snapshot -c new test.qcow2 Time drops from more than 3 minutes to under 1 second. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-03-15qcow2: flush in qcow2_update_snapshot_refcount()Stefan Hajnoczi1-1/+1
Users of qcow2_update_snapshot_refcount() do not flush consistently. qcow2_snapshot_create() flushes but qcow2_snapshot_goto() and qcow2_snapshot_delete() do not. Solve this by moving the bdrv_flush() into qcow2_update_snapshot_refcount(). Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-03-15qcow2: set L2 cache dependency in qcow2_alloc_bytes()Stefan Hajnoczi1-1/+5
Compressed writes use qcow2_alloc_bytes() to allocate space with byte granularity. The affected clusters' refcounts will be incremented but we do not need to flush yet. Set a L2 cache dependency on the refcount block cache, so that the refcounts get written out before the L2 updates. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-03-15qcow2: flush refcount cache correctly in alloc_refcount_block()Stefan Hajnoczi1-2/+8
update_refcount() affects the refcount cache, it does not write to disk. Therefore bdrv_flush(bs->file) does nothing. We need to flush the refcount cache in order to write out the refcount updates! While we're here also add error returns when qcow2_cache_flush() fails. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-02-22qcow2: support compressed clusters in BlockFragInfoStefan Hajnoczi1-0/+1
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-02-22qcow2: record fragmentation statistics during checkStefan Hajnoczi1-1/+24
The qemu-img check command can display fragmentation statistics: * Total number of clusters in virtual disk * Number of allocated clusters * Number of fragmented clusters This patch adds fragmentation statistics support to qcow2. Compressed and normal clusters count as allocated. Zero clusters are not counted as allocated unless their L2 entry has a non-zero offset (e.g. preallocation). Only the current L1 table counts towards the statistics - snapshots are ignored. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-02-22qcow2: introduce check_refcounts_l1/l2() flagsStefan Hajnoczi1-6/+12
The check_refcounts_l1/l2() functions have a check_copied argument to check that the QCOW_O_COPIED flag is consistent with refcount == 1. This should be a bool, not an int. However, the next patch introduces qcow2 fragmentation statistics and also needs to pass an option to check_refcounts_l1/l2(). This is a good opportunity to use an int flags field. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-02-22qemu-img: find the image end offset during checkFederico Simoncelli1-2/+8
This patch adds the support for reporting the image end offset (in bytes). This is particularly useful after a conversion (or a rebase) where the destination is a block device in order to find the first unused byte at the end of the image. Signed-off-by: Federico Simoncelli <fsimonce@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-01-30g_malloc(0) and g_malloc0(0) return NULL; simplifyMarkus Armbruster1-5/+1
Once upon a time, it was decided that qemu_malloc(0) should abort. Switching to glib retired that bright idea. Some code that was added to cope with it (e.g. in commits 702ef63, b76b6e9) is still around. Bury it. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2012-12-19block: move include files to include/block/Paolo Bonzini1-1/+1
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-11-14qcow2: Fix refcount table size calculationKevin Wolf1-1/+2
A missing factor for the refcount table entry size in the calculation could mean that too little memory was allocated for the in-memory representation of the table, resulting in a buffer overflow. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Michael Tokarev <mjt@tls.msk.ru> Tested-by: Michael Tokarev <mjt@tls.msk.ru>
2012-07-09qcow2: preserve free_byte_offset when qcow2_alloc_bytes() failsStefan Hajnoczi1-3/+4
When qcow2_alloc_clusters() error handling code was introduced in commit 5d757b563d59142ca81e1073a8e8396750a0ad1a, the value of free_byte_offset was clobbered in the error case. This patch keeps free_byte_offset at 0 so we will try to allocate clusters again next time this function is called. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-06-15qcow2: always operate caches in writeback modePaolo Bonzini1-12/+0
Writethrough does not need special-casing anymore in the qcow2 caches. The block layer adds flushes after every guest-initiated data write, and these will also flush the qcow2 caches to the OS. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-06-15qcow2: Support for fixing refcount inconsistenciesKevin Wolf1-9/+34
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-06-15qcow2: fix endianness conversionZhi Yong Wu1-1/+1
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com> Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-20qcow2: Support reading zero clustersKevin Wolf1-0/+7
This adds support for reading zero clusters in version 3 images. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-20qcow2: Ignore reserved bits in check_refcountsKevin Wolf1-44/+54
Also don't infer the cluster type directly from the L2 entries, but use qcow2_get_cluster_type() to keep everything in a single place. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-20qcow2: Ignore reserved bits in refcount table entriesKevin Wolf1-1/+1
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-20qcow2: Refactor qcow2_free_any_clustersKevin Wolf1-19/+22
Zero clusters will add another cluster type. Refactor the open-coded cluster type detection into a switch of QCOW2_CLUSTER_* options so that the detection is in a single place. This makes it easier to add new cluster types. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-20qcow2: Ignore reserved bits in L1/L2 entriesKevin Wolf1-6/+6
This changes the still existing places that assume that the only flags are QCOW_OFLAG_COPIED and QCOW_OFLAG_COMPRESSED to properly mask out reserved bits. It does not convert bdrv_check yet. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-20qcow2: Fix refcount block allocation during qcow2_alloc_cluster_at()Kevin Wolf1-0/+6
Refcount block allocation and refcount table growth rely on s->free_cluster_index pointing to somewhere after the current allocation. Change qcow2_alloc_cluster_at() to fulfill this assumption. Without this change it could happen that a newly allocated refcount block and the allocated data block point to the same area in the image file, causing data corruption in the long run. This fixes a bug that became first visible after commit 250196f1. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-19qcow2: Fix return value of alloc_refcount_blockKevin Wolf1-1/+1
Someone forgot something in commit 29c1a730... Documenting the right return value is not enough, you also need to actually return it in the code. This bug sometimes causes error return values even when everything has succeeded: The new offset of the refcount block is truncated to 32 bits and interpreted as signed. At least with small cluster sizes it's easy to get a negative return value this way. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
2012-03-12qcow2: Add qcow2_alloc_clusters_at()Kevin Wolf1-0/+28
This function allows to allocate clusters at a given offset in the image file. This is useful if you want to allocate the second part of an area that must be contiguous. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2011-12-05qcow2: Fix order of refcount updates in qcow2_snapshot_gotoKevin Wolf1-1/+6
The refcount updates must be moved so that in the worst case we can get cluster leaks, but refcounts may never be too low. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2011-08-25qcow2: remove unused qcow2_create_refcount_update functionFrediano Ziglio1-18/+0
Signed-off-by: Frediano Ziglio <freddy77@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-08-25qcow2: use always stderr for debuggingFrediano Ziglio1-2/+2
let all DEBUG_ALLOC2 printf goes to stderr Signed-off-by: Frediano Ziglio <freddy77@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-08-20Use glib memory allocation and free functionsAnthony Liguori1-17/+17
qemu_malloc/qemu_free no longer exist after this commit. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2011-07-19qcow2: Use Qcow2Cache in writeback mode during loadvm/savevmKevin Wolf1-11/+27
In snapshotting there is no guest involved, so we can safely use a writeback mode and do the flushes in the right place (i.e. at the very end). This improves the time that creating/restoring an internal snapshot takes with an image in writethrough mode. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-06-08qcow2: Fix memory leaks in error casesKevin Wolf1-3/+6
This fixes memory leaks that may be caused by I/O errors during L1 table growth (can happen during save_vm) and in qemu-img check. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-05-08Fix typos in comments and code (occured -> occurred and related)Stefan Weil1-1/+1
The code changed here is an unused data type name (evt_flush_occurred). Signed-off-by: Stefan Weil <weil@mail.berlios.de> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2011-01-31qcow2-refcount: remove write-only variablesBlue Swirl1-4/+1
Variables l2_modified and l2_size are not really used, remove them. Spotted by GCC 4.6.0: CC block/qcow2-refcount.o /src/qemu/block/qcow2-refcount.c: In function 'qcow2_update_snapshot_refcount': /src/qemu/block/qcow2-refcount.c:708:37: error: variable 'l2_modified' set but not used [-Werror=unused-but-set-variable] /src/qemu/block/qcow2-refcount.c:708:9: error: variable 'l2_size' set but not used [-Werror=unused-but-set-variable] CC: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Blue Swirl <blauwirbel@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-01-24qcow2: Use QcowCacheKevin Wolf1-153/+107
Use the new functions of qcow2-cache.c for everything that works on refcount block and L2 tables. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-11-04qcow2: Invalidate cache after failed readKevin Wolf1-0/+1
The cache content may be destroyed after a failed read, better not use it any more. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2010-10-13block: avoid a write only variableBlue Swirl1-0/+1
Compiling with GCC 4.6.0 20100925 produced a warning: /src/qemu/block/qcow2-refcount.c: In function 'update_refcount': /src/qemu/block/qcow2-refcount.c:552:13: error: variable 'dummy' set but not used [-Werror=unused-but-set-variable] Fix by adding a dummy cast so that the result is not unused. Acked-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2010-09-21qcow2: Move sync out of qcow2_alloc_clustersKevin Wolf1-2/+2
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-09-21qcow2: Move sync out of update_refcountKevin Wolf1-2/+11
Note that the flush is omitted intentionally in qcow2_free_clusters. If anything, we can leak clusters here if we lose the writes. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-09-21qcow2: Move sync out of write_refcount_block_entriesKevin Wolf1-1/+3
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
generated by cgit v1.2.1 (git 2.18.0) at 2024-06-26 12:02:22 +0000