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2013-11-29COW: Extend checking allocated bits to beyond one sectorCharlie Shepherd
cow_co_is_allocated() only checks one sector's worth of allocated bits before returning. This is allowed but (slightly) inefficient, so extend it to check all of the file's metadata sectors. Signed-off-by: Charlie Shepherd <charlie@ctshepherd.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> [kwolf: silenced compiler warning (-Wmaybe-uninitialized for changed)] Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-29COW: Speed up writesCharlie Shepherd
Process a whole sector's worth of COW bits by reading a sector, setting the bits after skipping any already set bits, then writing it out again. Make sure we only flush once before writing metadata, and only if we need to write metadata. Signed-off-by: Charlie Shepherd <charlie@ctshepherd.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-29qapi: Change BlockDirtyInfo to listFam Zheng
We have multiple dirty bitmaps in BDS now, switch QAPI to allow query it (BlockInfo.dirty_bitmaps), and also drop old BlockInfo.dirty. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-29block: per caller dirty bitmapFam Zheng
Previously a BlockDriverState has only one dirty bitmap, so only one caller (e.g. a block job) can keep track of writing. This changes the dirty bitmap to a list and creates a BdrvDirtyBitmap for each caller, the lifecycle is managed with these new functions: bdrv_create_dirty_bitmap bdrv_release_dirty_bitmap Where BdrvDirtyBitmap is a linked list wrapper structure of HBitmap. In place of bdrv_set_dirty_tracking, a BdrvDirtyBitmap pointer argument is added to these functions, since each caller has its own dirty bitmap: bdrv_get_dirty bdrv_dirty_iter_init bdrv_get_dirty_count bdrv_set_dirty and bdrv_reset_dirty prototypes are unchanged but will internally walk the list of all dirty bitmaps and set them one by one. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-28block/stream: Don't stream unbacked devicesMax Reitz
If a block device is unbacked, a streaming blockjob should immediately finish instead of beginning to try to stream, then noticing the backing file does not contain even the first sector (since it does not exist) and then finishing normally. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-28sheepdog: implement .bdrv_get_allocated_file_sizeLiu Yuan
With this patch, qemu-img info sheepdog:image will show disk size for sheepdog images. Cc: Kevin Wolf <kwolf@redhat.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Cc: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp> Signed-off-by: Liu Yuan <namei.unix@gmail.com> Reviewed-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-28iscsi: add bdrv_co_write_zeroesPeter Lieven
Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28iscsi: simplify iscsi_co_discardPeter Lieven
now that bdrv_co_discard can handle limits we do not need the request split logic here anymore. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28iscsi: set limits in BlockDriverStatePeter Lieven
Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28block/raw: copy BlockLimits on raw_openPeter Lieven
Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28block/iscsi: add .bdrv_get_infoPeter Lieven
Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28block: introduce BDRV_REQ_MAY_UNMAP request flagPeter Lieven
Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28block: add flags to bdrv_*_write_zeroesPeter Lieven
Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-14qcow2: fix possible corruption when reading multiple clustersPeter Lieven
if multiple sectors spanning multiple clusters are read the function count_contiguous_clusters should ensure that the cluster type should not change between the clusters. Especially the for-loop should break when we have one or more normal clusters followed by a compressed cluster. Unfortunately the wrong macro was used in the mask to compare the flags. This was discovered while debugging a data corruption issue when converting a compressed qcow2 image to raw. qemu-img reads 2MB chunks which span multiple clusters. CC: qemu-stable@nongnu.org Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-14block: Print its file name if backing file opening failedFam Zheng
If backing file doesn't exist, the error message is confusing and misleading: $ qemu /tmp/a.qcow2 qemu: could not open disk image /tmp/a.qcow2: Could not open file: No such file or directory But... $ ls /tmp/a.qcow2 /tmp/a.qcow2 $ qemu-img info /tmp/a.qcow2 image: /tmp/a.qcow2 file format: qcow2 virtual size: 8.0G (8589934592 bytes) disk size: 196K cluster_size: 65536 backing file: /tmp/b.qcow2 Because... $ ls /tmp/b.qcow2 ls: cannot access /tmp/b.qcow2: No such file or directory This is not intuitive. It's better to have the missing file's name in the error message. With this patch: $ qemu-io -c 'read 0 512' /tmp/a.qcow2 qemu-io: can't open device /tmp/a.qcow2: Could not open backing file: Could not open '/stor/vm/arch.raw': No such file or directory no file open, try 'help open' Which is a little bit better. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-07block: vhdx - add .bdrv_create() supportJeff Cody
This adds support for VHDX image creation, for images of type "Fixed" and "Dynamic". "Differencing" types (i.e., VHDX images with backing files) are currently not supported. Options for image creation include: * log size: The size of the journaling log for VHDX. Minimum is 1MB, and it must be a multiple of 1MB. Invalid log sizes will be silently fixed by rounding up to the nearest MB. Default is 1MB. * block size: This is the size of a payload block. The range is 1MB to 256MB, inclusive, and must be a multiple of 1MB as well. Invalid sizes and multiples will be silently fixed. If '0' is passed, then a sane size is chosen (depending on virtual image size). Default is 0 (Auto-select). * subformat: - "dynamic" An image without data pre-allocated. - "fixed" An image with data pre-allocated. Default is "dynamic" When creating the image file, the lettered sections are created: -----------------------------------------------------------------. | (A) | (B) | (C) | (D) | (E) | File ID | Header1 | Header 2 | Region Tbl 1 | Region Tbl 2 | | | | | .-----------------------------------------------------------------. 0 64KB 128KB 192KB 256KB 320KB .---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------. | (F) | (G) | (H) | | Journal Log | BAT / Bitmap | Metadata | .... data ...... | | | | .---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------. 1MB (var.) (var.) (var.) Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-07block: vhdx - fix comment typos in header, fix incorrect struct fieldsJeff Cody
VHDXPage83Data and VHDXParentLocatorHeader both incorrectly had their MSGUID fields set as arrays of 16. This is incorrect (it stems from an early version where those fields were uint_8 arrays). Those fields were, up to this patch, unused. Also, there were a couple of typos and incorrect wording in comments, and those have been fixed up as well. Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-07block: vhdx - break out code operations to functionsJeff Cody
This is preperation for vhdx_create(). The ability to write headers, and calculate the number of BAT entries will be needed within the create() functions, so move this relevant code into helper functions. Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-07block: vhdx - move more endian translations to vhdx-endian.cJeff Cody
In preparation for vhdx_create(), move more endian translation functions out to vhdx-endian.c. Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-07block: vhdx - remove BAT file offset bit shiftingJeff Cody
Bit shifting can be fun, but in this case it was unnecessary. The upper 44 bits of the 64-bit BAT entry is specifies the File Offset, so we shifted the bits to get access to the value. However, per the spec the value is in MB. So we dutifully shifted back to the left by 20 bits, to convert to a true uint64_t file offset. This replaces those steps with just a bit mask, to get rid of the lower 20 bits instead. Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-07block: vhdx write supportJeff Cody
This adds support for writing to VHDX image files, using coroutines. Writes into the BAT table goes through the VHDX log. Currently, BAT table writes occur when expanding a dynamic VHDX file, and allocating a new BAT entry. Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-07block: vhdx - add log write supportJeff Cody
This adds support for writing to the VHDX log. For spec details, see VHDX Specification Format v1.00: https://www.microsoft.com/en-us/download/details.aspx?id=34750 There are a few limitations to this log support: 1.) There is no caching yet 2.) The log is flushed after each entry The primary write interface, vhdx_log_write_and_flush(), performs a log write followed by an immediate flush of the log. As each log entry sector is a minimum of 4KB, partial sector writes are filled in with data from the disk write destination. If the current file log GUID is 0, a new GUID is generated and updated in the header. Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-07block: vhdx - add region overlap detection for image filesJeff Cody
Regions in the image file cannot overlap - the log, region tables, and metdata must all be unique and non-overlapping. This adds region checking by means of a QLIST; there can be a variable number of regions and metadata (there may be metadata or region tables that we do not recognize / know about, but are not required). This adds the capability to register a region for later checking, and to check against registered regions for any overlap. Also, if neither the BAT or Metadata region tables are found, return error. Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-07block: vhdx - log parsing, replay, and flush supportJeff Cody
This adds support for VHDX v0 logs, as specified in Microsoft's VHDX Specification Format v1.00: https://www.microsoft.com/en-us/download/details.aspx?id=34750 The following support is added: * Log parsing, and validation - validate that an existing log is correct. * Log search - search through an existing log, to find any valid sequence of entries. * Log replay and flush - replay an existing log, and flush/clear the log when complete. The VHDX log is a circular buffer, with elements (sectors) of 4KB. A log entry is a variably-length number of sectors, that is comprised of a header and 'descriptors', that describe each sector. A log may contain multiple entries, know as a log sequence. In a log sequence, each log entry immediately follows the previous entry, with an incrementing sequence number. There can only ever be one active and valid sequence in the log. Each log entry must match the file log GUID in order to be valid (along with other criteria). Once we have flushed all valid log entries, we marked the file log GUID to be zero, which indicates a buffer with no valid entries. Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-07block: vhdx code movement - move vhdx_close() above vhdx_open()Jeff Cody
Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-07block: vhdx - update log guid in header, and first write trackerJeff Cody
Allow tracking of first file write in the VHDX image, as well as the ability to update the GUID in the header. This is in preparation for log support. Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-07block: vhdx - break endian translation functions outJeff Cody
This moves the endian translation functions out from the vhdx.c source, into a separate source file. In addition to the previously defined endian functions, new endian translation functions for log support are added as well. Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-07block: vhdx - log support struct and definesJeff Cody
This adds some magic number defines, and internal structure definitions for VHDX log replay support. The struct VHDXLogEntries does not reflect an on-disk data structure, and thus does not need to be packed. Some minor code style fixes are applied as well. Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-07block: vhdx code movement - VHDXMetadataEntries and BDRVVHDXState to header.Jeff Cody
In preparation for VHDX log support, move these structures to the header. Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-07block: vhdx - add header update capability.Jeff Cody
This adds the ability to update the headers in a VHDX image, including generating a new MS-compatible GUID. As VHDX depends on uuid.h, VHDX is now a configurable build option. If VHDX support is enabled, that will also enable uuid as well. The default is to have VHDX enabled. To enable/disable VHDX: --enable-vhdx, --disable-vhdx Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-07block: vhdx - minor comments and typo correction.Jeff Cody
Just a couple of minor comments to help note where allocated buffers are freed, and a typo fix. Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-07block/vpc: fix virtual size for images created with disk2vhdPeter Lieven
Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-07block/raw-posix: fix FreeBSD compilationAndreas Tobler
The below patch is needed to compile qemu trunk on FreeBSD with gcc48, clang will fail.... ;). Host x84_64-freebsd. Signed-off-by: Andreas Tobler <andreast@FreeBSD.org> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-05bswap.h: Remove cpu_to_be64wu()Peter Maydell
Replace the legacy cpu_to_be64wu() with stq_be_p(). Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <rth@twiddle.net> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Message-id: 1383669517-25598-9-git-send-email-peter.maydell@linaro.org Signed-off-by: Anthony Liguori <aliguori@amazon.com>
2013-10-31Merge remote-tracking branch 'kwolf/tags/for-anthony' into stagingAnthony Liguori
Block patches for 1.7.0-rc0 (v2) # gpg: Signature made Thu 31 Oct 2013 04:44:39 PM CET using RSA key ID C88F2FD6 # gpg: Can't check signature: public key not found * kwolf/tags/for-anthony: (30 commits) vmdk: Implment bdrv_get_specific_info qapi: Add optional field 'compressed' to ImageInfo qemu-iotests: prefill some data to test image sheepdog: check simultaneous create in resend_aioreq sheepdog: cancel aio requests if possible sheepdog: make add_aio_request and send_aioreq void functions sheepdog: try to reconnect to sheepdog after network error coroutine: add co_aio_sleep_ns() to allow sleep in block drivers sheepdog: reload inode outside of resend_aioreq sheepdog: handle vdi objects in resend_aio_req sheepdog: check return values of qemu_co_recv/send correctly qemu-iotests: Test case for backing file deletion qemu-iotests: drop duplicated "create_image" qemu-iotests: Fix 051 reference output block: Avoid unecessary drv->bdrv_getlength() calls block: Disable BDRV_O_COPY_ON_READ for the backing file ahci: fix win7 hang on boot sheepdog: pass copy_policy in the request sheepdog: explicitly set copies as type uint8_t block: Don't copy backing file name on error ... Message-id: 1383064269-27720-1-git-send-email-kwolf@redhat.com Signed-off-by: Anthony Liguori <anthony@codemonkey.ws>
2013-10-31vmdk: Implment bdrv_get_specific_infoFam Zheng
Implement .bdrv_get_specific_info to return the extent information. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-30sheepdog: check simultaneous create in resend_aioreqMORITA Kazutaka
After reconnection happens, all the inflight requests are moved to the failed request list. As a result, sd_co_rw_vector() can send another create request before resend_aioreq() resends a create request from the failed list. This patch adds a helper function check_simultaneous_create() and checks simultaneous create requests more strictly in resend_aioreq(). Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp> Tested-by: Liu Yuan <namei.unix@gmail.com> Reviewed-by: Liu Yuan <namei.unix@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-30sheepdog: cancel aio requests if possibleMORITA Kazutaka
This patch tries to cancel aio requests in pending queue and failed queue. When the sheepdog driver cannot cancel the requests, it waits for them to be completed. Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp> Tested-by: Liu Yuan <namei.unix@gmail.com> Reviewed-by: Liu Yuan <namei.unix@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-30sheepdog: make add_aio_request and send_aioreq void functionsMORITA Kazutaka
These functions no longer return errors. We can make them void functions and simplify the codes. Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp> Tested-by: Liu Yuan <namei.unix@gmail.com> Reviewed-by: Liu Yuan <namei.unix@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-30sheepdog: try to reconnect to sheepdog after network errorMORITA Kazutaka
This introduces a failed request queue and links all the inflight requests to the list after network error happens. After QEMU reconnects to the sheepdog server successfully, the sheepdog block driver will retry all the requests in the failed queue. Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp> Tested-by: Liu Yuan <namei.unix@gmail.com> Reviewed-by: Liu Yuan <namei.unix@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-30sheepdog: reload inode outside of resend_aioreqMORITA Kazutaka
This prepares for using resend_aioreq() after reconnecting to the sheepdog server. Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp> Tested-by: Liu Yuan <namei.unix@gmail.com> Reviewed-by: Liu Yuan <namei.unix@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-30sheepdog: handle vdi objects in resend_aio_reqMORITA Kazutaka
The current resend_aio_req() doesn't work when the request is against vdi objects. This fixes the problem. Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp> Tested-by: Liu Yuan <namei.unix@gmail.com> Reviewed-by: Liu Yuan <namei.unix@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-30sheepdog: check return values of qemu_co_recv/send correctlyMORITA Kazutaka
If qemu_co_recv/send doesn't return the specified length, it means that an error happened. Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp> Tested-by: Liu Yuan <namei.unix@gmail.com> Reviewed-by: Liu Yuan <namei.unix@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-29block: Avoid unecessary drv->bdrv_getlength() callsKevin Wolf
The block layer generally keeps the size of an image cached in bs->total_sectors so that it doesn't have to perform expensive operations to get the size whenever it needs it. This doesn't work however when using a backend that can change its size without qemu being aware of it, i.e. passthrough of removable media like CD-ROMs or floppy disks. For this reason, the caching is disabled when a removable device is used. It is obvious that checking whether the _guest_ device has removable media isn't the right thing to do when we want to know whether the size of the host backend can change. To make things worse, non-top-level BlockDriverStates never have any device attached, which makes qemu assume they are removable, so drv->bdrv_getlength() is always called on the protocol layer. In the case of raw-posix, this causes unnecessary lseek() system calls, which turned out to be rather expensive. This patch completely changes the logic and disables bs->total_sectors caching only for certain block driver types, for which a size change is expected: host_cdrom and host_floppy on POSIX, host_device on win32; also the raw format in case it sits on top of one of these protocols, but in the common case the nested bdrv_getlength() call on the protocol driver will use the cache again and avoid an expensive drv->bdrv_getlength() call. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
2013-10-28sheepdog: pass copy_policy in the requestLiu Yuan
Currently copy_policy isn't used. Recent sheepdog supports erasure coding, which make use of copy_policy internally, but require client explicitly passing copy_policy from base inode to newly creately inode for snapshot related operations. If connected sheep daemon doesn't utilize copy_policy, passing it to sheep daemon is just one extra null effect operation. So no compatibility problem. With this patch, sheepdog can provide erasure coded volume for QEMU VM. Cc: Kevin Wolf <kwolf@redhat.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Liu Yuan <namei.unix@gmail.com> Acked-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-28sheepdog: explicitly set copies as type uint8_tLiu Yuan
'copies' is actually uint8_t since day one, but request headers and some helper functions parameterize it as uint32_t for unknown reasons and effectively reserve 24 bytes for possible future use. This patch explicitly set the correct for copies and reserve the left bytes. This is a preparation patch that allow passing copy_policy in request header. Cc: Kevin Wolf <kwolf@redhat.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Liu Yuan <namei.unix@gmail.com> Acked-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-28qcow2: Flush image after creationMax Reitz
Opening the qcow2 image with BDRV_O_NO_FLUSH prevents any flushes during the image creation. This means that the image has not yet been flushed to disk when qemu-img create exits. This flush is delayed until the next operation on the image involving opening it without BDRV_O_NO_FLUSH and closing (or directly flushing) it. For large images and/or images with a small cluster size and preallocated metadata, this flush may take a significant amount of time and may occur unexpectedly. Reopening the image without BDRV_O_NO_FLUSH right before the end of qcow2_create2() results in hoisting the potentially costly flush into the image creation, which is expected to take some time (whereas successive image operations may be not). Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-26misc: New spelling fixes in commentsStefan Weil
compatiblity -> compatibility continously -> continuously existance -> existence usefull -> useful shoudl -> should Signed-off-by: Stefan Weil <sw@weilnetz.de> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2013-10-24block/vpc: check that the image has not been truncatedPeter Lieven
this adds a check that a dynamic VHD file has not been accidently truncated (e.g. during transfer or upload). Signed-off-by: Peter Lieven <pl@kamp.de> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-24qcow2: Unset zero_beyond_eof in save_vmstateMax Reitz
Saving the VM state is done using bdrv_pwrite. This function may perform a read-modify-write, which in this case results in data being read from beyond the end of the virtual disk. Since we are actually trying to access an area which is not a part of the virtual disk, zero_beyond_eof has to be set to false before performing the partial write, otherwise the VM state may become corrupted. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>