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path: root/block/qcow2-refcount.c
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2013-03-15qcow2: drop unnecessary flush in qcow2_update_snapshot_refcount()Stefan Hajnoczi
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 Hajnoczi
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 Hajnoczi
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 Hajnoczi
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 Hajnoczi
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 Hajnoczi
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-02-22qcow2: record fragmentation statistics during checkStefan Hajnoczi
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 Hajnoczi
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 Simoncelli
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 Armbruster
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 Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-11-14qcow2: Fix refcount table size calculationKevin Wolf
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 Hajnoczi
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 Bonzini
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 Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-06-15qcow2: fix endianness conversionZhi Yong Wu
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 Wolf
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 Wolf
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 Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-20qcow2: Refactor qcow2_free_any_clustersKevin Wolf
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 Wolf
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 Wolf
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 Wolf
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 Wolf
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 Wolf
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 Ziglio
Signed-off-by: Frediano Ziglio <freddy77@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-08-25qcow2: use always stderr for debuggingFrediano Ziglio
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 Liguori
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 Wolf
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 Wolf
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 Weil
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 Swirl
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 Wolf
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 Wolf
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 Swirl
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 Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-09-21qcow2: Move sync out of update_refcountKevin Wolf
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 Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-07-06qcow2/vdi: Change check to distinguish error casesKevin Wolf
This distinguishes between harmless leaks and real corruption. Hopefully users better understand what qemu-img check wants to tell them. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-06-22qcow2: Don't try to check tables that couldn't be loadedKevin Wolf
Trying to check them leads to a second error message which is more confusing than helpful: Can't get refcount for cluster 0: Invalid argument ERROR cluster 0 refcount=-22 reference=1 Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-06-22qcow2: Fix qemu-img check segfault on corrupted imagesKevin Wolf
With corrupted images, we can easily get an cluster index that exceeds the array size of the temporary refcount table. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-06-22qcow2: Use bdrv_(p)write_sync for metadata writesKevin Wolf
Use bdrv_(p)write_sync to ensure metadata integrity in case of a crash. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-06-15qcow2: Return real error code in load_refcount_blockKevin Wolf
This fixes load_refcount_block which completely ignored the return value of write_refcount_block and always returned -EIO for bdrv_pwrite failure. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-06-15qcow2: Allow alloc_clusters_noref to return errorsKevin Wolf
Currently it would consider blocks for which get_refcount fails used. However, it's unlikely that get_refcount would succeed for the next cluster, so it's not really helpful. Return an error instead. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-06-15qcow2: Allow get_refcount to return errorsKevin Wolf
get_refcount might need to load a refcount block from disk, so errors may happen. Return the error code instead of assuming a refcount of 1 and change the callers to respect error return values. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-28qcow2: Fix corruption after error in update_refcountKevin Wolf
After it is done with updating refcounts in the cache, update_refcount writes all changed entries to disk. If a refcount block allocation fails, however, there was no change yet and therefore first_index = last_index = -1. Don't treat -1 as a normal sector index (resulting in a 512 byte write!) but return without updating anything in this case. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-28qcow2: Fix corruption after refblock allocationKevin Wolf
Refblock allocation code needs to take into consideration that update_refcount will load a different refcount block into the cache, so it must initialize the cache for a new refcount block only afterwards. Not doing this means that not only the refcount in the wrong block is updated, but also that the caller will work on the wrong block. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-28qcow2: Return right error code in write_refcount_block_entriesKevin Wolf
write_refcount_block_entries used to return -EIO for any errors. Change this to return the real error code. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-03qcow2: Remove abort on free_clusters failureKevin Wolf
While it's true that during regular operation free_clusters failure would be a bug, an I/O error can always happen. There's no need to kill the VM, the worst thing that can happen (and it will) is that we leak some clusters. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-03qcow2: Avoid shadowing variable in alloc_clusters_noref()Stefan Hajnoczi
The i loop iterator is shadowed by the next free cluster index. Both using the variable name 'i' makes the code harder to read. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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