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path: root/block/qcow2.c
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2014-03-13qcow2: Don't write with BDRV_O_INCOMINGKevin Wolf1-5/+7
qcow2_open() causes writes when repairing an image with the dirty flag set and when clearing autoclear flags. It shouldn't do this when another qemu instance is still actively working on this image file. One effect of the bug is that images may have a cleared dirty flag while the migration source host still has it in use with lazy refcounts enabled, so refcounts are not accurate and the dirty flag must remain set. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-03-13qcow2: Keep option in qcow2_invalidate_cache()Kevin Wolf1-4/+1
Instead of manually building a list of all options from BDRVQcowState values just reuse the options that were used to open the image. qcow2_open() won't fully use all of the options in the QDict, but that's okay. This fixes all of the driver-specific options in qcow2, except for lazy-refcounts, which was special cased before. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-03-13block: Update image size in bdrv_invalidate_cache()Kevin Wolf1-0/+2
After migration has completed, we call bdrv_invalidate_cache() so that drivers which cache some data drop their stale copy of the data and reread it from the image file to get a new version of data that the source modified while the migration was running. Reloading metadata from the image file is useless, though, if the size of the image file stays stale (this is a value that is cached for all image formats in block.c). Reads from (meta)data after the old EOF return only zeroes, causing image corruption. We need to update bs->total_sectors in all layers that could potentially have changed their size (i.e. backing files are not a concern - if they are changed, we're in bigger trouble) Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-02-21block: do not abuse EMEDIUMTYPEPaolo Bonzini1-1/+1
Returning "Wrong medium type" for an image that does not have a valid header is a bit weird. Improve the error by mentioning what format was trying to open it. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21block: Make bdrv_file_open() staticMax Reitz1-1/+3
Add the bdrv_open() option BDRV_O_PROTOCOL which results in passing the call to bdrv_file_open(). Additionally, make bdrv_file_open() static and therefore bdrv_open() the only way to call it. Consequently, all existing calls to bdrv_file_open() have to be adjusted to use bdrv_open() with the BDRV_O_PROTOCOL flag instead. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21block: Add reference parameter to bdrv_open()Max Reitz1-2/+2
Allow bdrv_open() to handle references to existing block devices just as bdrv_file_open() is already capable of. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21block: Change BDS parameter of bdrv_open() to **Max Reitz1-5/+9
Make bdrv_open() take a pointer to a BDS pointer, similarly to bdrv_file_open(). If a pointer to a NULL pointer is given, bdrv_open() will create a new BDS with an empty name; if the BDS pointer is not NULL, that existing BDS will be reused (in the same way as bdrv_open() already did). Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-17Use error_is_set() only when necessaryMarkus Armbruster1-3/+3
error_is_set(&var) is the same as var != NULL, but it takes whole-program analysis to figure that out. Unnecessarily hard for optimizers, static checkers, and human readers. Dumb it down to obvious. Gets rid of several dozen Coverity false positives. Note that the obvious form is already used in many places. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Andreas Färber <afaerber@suse.de> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-02-09qcow2: check for NULL l2metaHu Tao1-15/+16
In the case of a metadata preallocation with a large cluster size, qcow2_alloc_cluster_offset() can allocate nothing and returns a NULL l2meta. This patch checks for it and link2 l2 with only valid l2meta. Replace 9 and 512 with BDRV_SECTOR_BITS, BDRV_SECTOR_SIZE respectively while at the function. Signed-off-by: Hu Tao <hutao@cn.fujitsu.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-09qcow2: remove n_start and n_end of qcow2_alloc_cluster_offset()Hu Tao1-6/+7
n_start can be actually calculated from offset. The number of sectors to be allocated(n_end - n_start) can be passed in in num. By removing n_start and n_end, we can save two parameters. The side effect is there is a bug in qcow2.c:preallocate() that passes incorrect n_start to qcow2_alloc_cluster_offset() is fixed. The bug can be triggerred by a larger cluster size than the default value(65536), for example: ./qemu-img create -f qcow2 \ -o 'cluster_size=131072,preallocation=metadata' file.img 4G Signed-off-by: Hu Tao <hutao@cn.fujitsu.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-01-31block: remove qcow2 .bdrv_make_empty implementationJeff Cody1-21/+0
The QCOW2 .bdrv_make_empty implementation always returns 0 for success, but does not actually do anything. The proper way to not support an optional driver function stub is to just not implement it, so let's remove the stub. Signed-off-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-01-24block: Move initialisation of BlockLimits to bdrv_refresh_limits()Kevin Wolf1-1/+10
This function separates filling the BlockLimits from bdrv_open(), which allows it to call it from other operations which may change the limits (e.g. modifications to the backing file chain or bdrv_reopen) Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-01-22block: Allow reference for bdrv_file_open()Max Reitz1-1/+1
Allow specifying a reference to an existing block device (by name) for bdrv_file_open() instead of a filename and/or options. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-01-06qemu-option: Remove qemu_opts_create_nofailPeter Crosthwaite1-1/+1
This is a boiler-plate _nofail variant of qemu_opts_create. Remove and use error_abort in call sites. null/0 arguments needs to be added for the id and fail_if_exists fields in affected callsites due to argument inconsistency between the normal and no_fail variants. Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2013-12-04qcow2: Zero-initialise first cluster for new imagesKevin Wolf1-16/+20
Strictly speaking, this is only required for has_zero_init() == false, but it's easy enough to just do a cluster-aligned write that is padded with zeros after the header. This fixes that after 'qemu-img create' header extensions are attempted to be parsed that are really just random leftover data. Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03block drivers: expose requirement for write same alignment from formatsPaolo Bonzini1-0/+1
This will let misaligned but large requests use zero clusters. This is important because the cluster size is not guest visible. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03block drivers: add discard/write_zeroes properties to bdrv_get_info ↵Paolo Bonzini1-0/+2
implementation Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-29block: Use BDRV_O_NO_BACKING where appropriateKevin Wolf1-1/+2
If you open an image temporarily just because you want to check its size or get it flushed, there's no real reason to open the whole backing file chain. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2013-11-28block: add flags to bdrv_*_write_zeroesPeter Lieven1-1/+1
Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-10-28qcow2: Flush image after creationMax Reitz1-0/+10
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>
2013-10-24qcow2: Unset zero_beyond_eof in save_vmstateMax Reitz1-0/+3
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>
2013-10-24qcow2: Restore total_sectors value in save_vmstateMax Reitz1-0/+6
Since df2a6f29a5, bdrv_co_do_writev increases the total_sectors value of a growable block devices on writes after the current end. This leads to the virtual disk apparently growing in qcow2_save_vmstate, which in turn affects the disk size captured by the internal snapshot taken directly afterwards through e.g. the HMP savevm command. Such a "grown" snapshot cannot be loaded after reopening the qcow2 image, since its disk size differs from the actual virtual disk size (writing a VM state does not actually increase the virtual disk size). Fix this by restoring total_sectors at the end of qcow2_save_vmstate. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-11qcow2: Evaluate overlap check optionsMax Reitz1-1/+28
Evaluate the runtime overlap check options and set BDRVQcowState.overlap_check appropriately. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-11qcow2: Array assigning options to OL check bitsMax Reitz1-0/+11
Add an array which assigns the option string to its corresponding overlap check bit. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-11qcow2: Add overlap-check optionsMax Reitz1-0/+46
Add runtime options to tune the overlap checks to be performed before write accesses. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-11qcow2: Make overlap check mask variableMax Reitz1-0/+2
Replace the QCOW2_OL_DEFAULT macro by a variable overlap_check in BDRVQcowState. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-11qcow2: Use negated overflow check maskMax Reitz1-3/+2
In qcow2_check_metadata_overlap and qcow2_pre_write_overlap_check, change the parameter signifying the checks to perform from its current positive form to a negative one, i.e., it will no longer explicitly specify every check to perform but rather a mask of checks not to perform. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-11qcow2: Remove wrong metadata overlap checkMax Reitz1-8/+0
In qcow2_write_compressed, if the compression fails, a normal cluster is written to disk. This is done through bdrv_write on the qcow2 BDS itself (using the guest offset), thus it is wrong to do a metadata overlap check before. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-11qcow2: Add missing space in error messageMax Reitz1-1/+1
The error message in qcow2_downgrade about an unsupported refcount order is missing a space. This patch adds it. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-11qcow2: Add support for ImageInfoSpecificMax Reitz1-0/+28
Add a new ImageInfoSpecificQCow2 type as a subtype of ImageInfoSpecific. This contains the compatibility level as a string and an optional lazy_refcounts boolean (optional means mandatory for compat >= 1.1 and not available for compat == 0.10). Also, add qcow2_get_specific_info, which returns this information. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-25block: qcow2 - used QEMU_PACKED for on-disk structuresJeff Cody1-1/+1
QCowHeader and QCowExtension are structs that reside in the on-disk image format, and are read and written directly via bdrv_pread()/write(), and as such should be packed to avoid any unintentional struct padding. Signed-off-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-12qcow2: Use Error parameterMax Reitz1-46/+88
Employ usage of the new Error ** parameter in qcow2_open, qcow2_create and associated functions. Signed-off-by: Max Reitz <mreitz@redhat.com>
2013-09-12block: Error parameter for create functionsMax Reitz1-1/+1
Add an Error ** parameter to bdrv_create and its associated functions to allow more specific error messages. Signed-off-by: Max Reitz <mreitz@redhat.com>
2013-09-12block: Error parameter for open functionsMax Reitz1-2/+2
Add an Error ** parameter to bdrv_open, bdrv_file_open and associated functions to allow more specific error messages. Signed-off-by: Max Reitz <mreitz@redhat.com>
2013-09-12bdrv: Use "Error" for creating imagesMax Reitz1-1/+2
Add an Error ** parameter to BlockDriver.bdrv_create to allow more specific error messages. Signed-off-by: Max Reitz <mreitz@redhat.com>
2013-09-12bdrv: Use "Error" for opening imagesMax Reitz1-2/+3
Add an Error ** parameter to BlockDriver.bdrv_open and BlockDriver.bdrv_file_open to allow more specific error messages. Signed-off-by: Max Reitz <mreitz@redhat.com>
2013-09-12qcow2: Implement bdrv_amend_optionsMax Reitz1-0/+194
Implement bdrv_amend_options for compat, size, backing_file, backing_fmt and lazy_refcounts. Downgrading images from compat=1.1 to compat=0.10 is achieved through handling all incompatible flags accordingly, clearing all compatible and autoclear flags and expanding all zero clusters. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-12qcow2: Save refcount order in BDRVQcowStateMax Reitz1-1/+2
Save the image refcount order in BDRVQcowState. This will be relevant for future code supporting different refcount orders than four and also for code that needs to verify a certain refcount order for an opened image. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-12qcow2: Discard VM state in active L1 after creating snapshotKevin Wolf1-5/+0
During savevm, the VM state is written to the active L1 of the image and then a snapshot is taken. After that, the VM state isn't needed any more in the active L1 and should be discarded. This is implemented by this patch. The impact of not discarding the VM state is that a snapshot can never become smaller than any previous snapshot (because it would be padded with old VM state), and more importantly that future savevm operations cause unnecessary COWs (with associated flushes), which makes subsequent snapshots much slower. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2013-09-12qcow2: Pass discard type to qcow2_discard_clusters()Kevin Wolf1-1/+1
The function will be used internally instead of only being called for guest discard requests. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2013-09-06block: return get_block_status data and flags for formatsPaolo Bonzini1-2/+14
Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-09-06block: introduce bdrv_get_block_status APIPaolo Bonzini1-2/+2
For now, bdrv_get_block_status is just another name for bdrv_is_allocated. The next patches will add more flags. This also touches all block drivers with a mostly mechanical rename. The sole exception is cow; because it calls cow_co_is_allocated from the read code, we keep that function and make cow_co_get_block_status a wrapper. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-09-06block: expect errors from bdrv_co_is_allocatedPaolo Bonzini1-3/+1
Some bdrv_is_allocated callers do not expect errors, but the fallback in qcow2.c might make other callers trip on assertion failures or infinite loops. Fix the callers to always look for errors. Cc: qemu-stable@nongnu.org Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-09-06block: make bdrv_delete() staticFam Zheng1-1/+1
Manage BlockDriverState lifecycle with refcnt, so bdrv_delete() is no longer public and should be called by bdrv_unref() if refcnt is decreased to 0. This is an identical change because effectively, there's no multiple reference of BDS now: no caller of bdrv_ref() yet, only bdrv_new() sets bs->refcnt to 1, so all bdrv_unref() now actually delete the BDS. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-09-02qcow2_check: Mark image consistentMax Reitz1-1/+5
If no corruptions remain after an image repair (and no errors have been encountered), clear the corrupt flag in qcow2_check. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-08-30qcow2: Employ metadata overlap checksMax Reitz1-0/+26
The pre-write overlap check function is now called before most of the qcow2 writes (aborting it on collision or other error). Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-08-30qcow2: Add corrupt bitMax Reitz1-0/+47
This adds an incompatible bit indicating corruption to qcow2. Any image with this bit set may not be written to unless for repairing (and subsequently clearing the bit if the repair has been successful). Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-08-30qcow2: Change default for new images to compat=1.1Kevin Wolf1-1/+3
By the time that qemu 1.7 will be released, enough time will have passed since qemu 1.1, which is the first version to understand version 3 images, that changing the default shouldn't hurt many people any more and the benefits of using the new format outweigh the pain. qemu-iotests already runs with compat=1.1 by default. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2013-08-22block: Introduce bs->zero_beyond_eofAsias He1-0/+3
In 4146b46c42e0989cb5842e04d88ab6ccb1713a48 (block: Produce zeros when protocols reading beyond end of file), we break qemu-iotests ./check -qcow2 022. This happens because qcow2 temporarily sets ->growable = 1 for vmstate accesses (which are stored beyond the end of regular image data). We introduce the bs->zero_beyond_eof to allow qcow2_load_vmstate() to disable ->zero_beyond_eof temporarily in addition to enable ->growable. [Since the broken patch "block: Produce zeros when protocols reading beyond end of file" has not been merged yet, I have applied this fix *first* and will then apply the next patch to keep the tree bisectable. -- Stefan] Suggested-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Asias He <asias@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-08-21qcow2: Change default for new images to compat=1.1Kevin Wolf1-1/+1
By the time that qemu 1.7 will be released, enough time will have passed since qemu 1.1, which is the first version to understand version 3 images, that changing the default shouldn't hurt many people any more and the benefits of using the new format outweigh the pain. qemu-iotests already runs with compat=1.1 by default. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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