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2014-08-15blkdebug: report errors on flush tooPaolo Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: John Snow <jsnow@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15qcow2: Catch !*host_offset for data allocationMax Reitz
qcow2_alloc_cluster_offset() uses host_offset == 0 as "no preferred offset" for the (data) cluster range to be allocated. However, this offset is actually valid and may be allocated on images with a corrupted refcount table or first refcount block. In this case, the corruption prevention should normally catch that write anyway (because it would overwrite the image header). But since 0 is a special value here, the function assumes that nothing has been allocated at all which it asserts against. Because this condition is not qemu's fault but rather that of a broken image, it shouldn't throw an assertion but rather mark the image corrupt and show an appropriate message, which this patch does by calling the corruption check earlier than it would be called normally (before the assertion). Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-15qcow2: Return useful error code in refcount_init()Max Reitz
If bdrv_pread() returns an error, it is very unlikely that it was ENOMEM. In this case, the return value should be passed along; as bdrv_pread() will always either return the number of bytes read or a negative value (the error code), the condition for checking whether bdrv_pread() failed can be simplified (and clarified) as well. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-15mirror: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the mirror block job. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-15vpc: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the vpc block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-15vmdk: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the vmdk block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-15vhdx: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the vhdx block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-15vdi: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the vdi block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-15rbd: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the rbd block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15raw-win32: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the raw-win32 block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15raw-posix: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the raw-posix block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15qed: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the qed block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-15qcow2: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the qcow2 block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15qcow1: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the qcow1 block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15parallels: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the parallels block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-15nfs: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the nfs block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-15iscsi: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the iscsi block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Eric Blake <eblake@redhat.com>
2014-08-15dmg: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the dmg block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-15curl: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the curl block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-15cloop: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the cloop block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-15bochs: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the bochs block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-15block: vpc - use block layer ops in vpc_create, instead of posix callsJeff Cody
Use the block layer to create, and write to, the image file in the VPC .bdrv_create() operation. This has a couple of benefits: Images can now be created over protocols, and hacks such as NOCOW are not needed in the image format driver, and the underlying file protocol appropriate for the host OS can be relied upon. Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-15block: use the standard 'ret' instead of 'result'Jeff Cody
Most QEMU code uses 'ret' for function return values. The VDI driver uses a mix of 'result' and 'ret'. This cleans that up, switching over to the standard 'ret' usage. Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-15block: vdi - use block layer ops in vdi_create, instead of posix callsJeff Cody
Use the block layer to create, and write to, the image file in the VDI .bdrv_create() operation. This has a couple of benefits: Images can now be created over protocols, and hacks such as NOCOW are not needed in the image format driver, and the underlying file protocol appropriate for the host OS can be relied upon. Also some minor cleanup for error handling. Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-15block: VHDX endian fixesJeff Cody
This patch contains several changes for endian conversion fixes for VHDX, particularly for big-endian machines (multibyte values in VHDX are all on disk in LE format). Tests were done with existing qemu-iotests on an IBM POWER7 (8406-71Y). This includes sample images created by Hyper-V, both with dirty logs and without. In addition, VHDX image files created (and written to) on a BE machine were tested on a LE machine, and vice-versa. Reported-by: Markus Armburster <armbru@redhat.com> Reported-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-15block: vhdx - add error checkJeff Cody
This add an error check for an invalid descriptor entry signature, when flushing the log descriptor entries. Signed-off-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-15block/archipelago: Add support for creating imagesChrysostomos Nanakos
qemu-img archipelago:<volumename>[/mport=<mapperd_port>[:vport=<vlmcd_port>] [:segment=<segment_name>]] [size] Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15block/archipelago: Implement bdrv_parse_filename()Chrysostomos Nanakos
VM Image on Archipelago volume can also be specified like this: file=archipelago:<volumename>[/mport=<mapperd_port>[:vport=<vlmcd_port>][: segment=<segment_name>]] Examples: file=archipelago:my_vm_volume file=archipelago:my_vm_volume/mport=123 file=archipelago:my_vm_volume/mport=123:vport=1234 file=archipelago:my_vm_volume/mport=123:vport=1234:segment=my_segment Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15block: Support Archipelago as a QEMU block backendChrysostomos Nanakos
VM Image on Archipelago volume is specified like this: file.driver=archipelago,file.volume=<volumename>[,file.mport=<mapperd_port>[, file.vport=<vlmcd_port>][,file.segment=<segment_name>]] 'archipelago' is the protocol. 'mport' is the port number on which mapperd is listening. This is optional and if not specified, QEMU will make Archipelago to use the default port. 'vport' is the port number on which vlmcd is listening. This is optional and if not specified, QEMU will make Archipelago to use the default port. 'segment' is the name of the shared memory segment Archipelago stack is using. This is optional and if not specified, QEMU will make Archipelago to use the default value, 'archipelago'. Examples: file.driver=archipelago,file.volume=my_vm_volume file.driver=archipelago,file.volume=my_vm_volume,file.mport=123 file.driver=archipelago,file.volume=my_vm_volume,file.mport=123, file.vport=1234 file.driver=archipelago,file.volume=my_vm_volume,file.mport=123, file.vport=1234,file.segment=my_segment Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-15qemu-img info: show nocow infoChunyan Liu
Add nocow info in 'qemu-img info' output to show whether the file currently has NOCOW flag set or not. Signed-off-by: Chunyan Liu <cyliu@suse.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15vmdk: Optimize cluster allocationFam Zheng
This drops the unnecessary bdrv_truncate() from, and also improves, cluster allocation code path. Before, when we need a new cluster, get_cluster_offset truncates the image to bdrv_getlength() + cluster_size, and returns the offset of added area, i.e. the image length before truncating. This is not efficient, so it's now rewritten as: - Save the extent file length when opening. - When allocating cluster, use the saved length as cluster offset. - Don't truncate image, because we'll anyway write data there: just write any data at the EOF position, in descending priority: * New user data (cluster allocation happens in a write request). * Filling data in the beginning and/or ending of the new cluster, if not covered by user data: either backing file content (COW), or zero for standalone images. One major benifit of this change is, on host mounted NFS images, even over a fast network, ftruncate is slow (see the example below). This change significantly speeds up cluster allocation. Comparing by converting a cirros image (296M) to VMDK on an NFS mount point, over 1Gbe LAN: $ time qemu-img convert cirros-0.3.1.img /mnt/a.raw -O vmdk Before: real 0m21.796s user 0m0.130s sys 0m0.483s After: real 0m2.017s user 0m0.047s sys 0m0.190s We also get rid of unchecked bdrv_getlength() and bdrv_truncate(), and get a little more documentation in function comments. Tested that this passes qemu-iotests for all VMDK subformats. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15block: Avoid bdrv_get_geometry() where errors should be detectedMarkus Armbruster
bdrv_get_geometry() hides errors. Use bdrv_nb_sectors() or bdrv_getlength() instead where that's obviously inappropriate. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15block: Drop superfluous aligning of bdrv_getlength()'s valueMarkus Armbruster
It returns a multiple of the sector size. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15block: Use bdrv_nb_sectors() where sectors, not bytes are wantedMarkus Armbruster
Instead of bdrv_getlength(). Aside: a few of these callers don't handle errors. I didn't investigate whether they should. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-18raw-posix: Fail gracefully if no working alignment is foundKevin Wolf
If qemu couldn't find out what O_DIRECT alignment to use with a given file, it would run into assert(bdrv_opt_mem_align(bs) != 0); in block.c and confuse users. This adds a more descriptive error message for such cases. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-18block: Add Error argument to bdrv_refresh_limits()Kevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-18qcow2: Fix error path for unknown incompatible featuresKevin Wolf
qcow2's report_unsupported_feature() had two bugs: A 32 bit truncation would prevent feature table entries for bits 32-63 from being used, and it could assign errp multiple times if there was more than one unknown feature, resulting in an error_set() assertion failure. Fix the truncation, make sure to set the error exactly once and add a qemu-iotests case for it. This fixes https://bugs.launchpad.net/qemu/+bug/1342704/ Reported-by: Maria Kustova <maria.k@catit.be> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-15linux-aio: Fix laio resource leakGonglei
when hotplug virtio-scsi disks using laio, the aio_nr will increase in laio_init() by io_setup(), we can see the number by # cat /proc/sys/fs/aio-nr 128 if the aio_nr attach the maxnum, which found from # cat /proc/sys/fs/aio-max-nr 65536 the hotplug process will fail because of aio context leak. Fix it by io_destroy in laio_cleanup(). Reported-by: daifulai <daifulai@huawei.com> Signed-off-by: Gonglei <arei.gonglei@huawei.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-14block: Assert qiov length matches request lengthKevin Wolf
At least raw-posix relies on this because it can allocate bounce buffers based on the request length, but access it using all of the qiov entries later. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-07-14qed: Make qiov match request size until backing file EOFKevin Wolf
If a QED image has a shorter backing file and a read request to unallocated clusters goes across EOF of the backing file, the backing file sees a shortened request and the rest is filled with zeros. However, the original too long qiov was used with the shortened request. This patch makes the qiov size match the request size, avoiding a potential buffer overflow in raw-posix. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2014-07-14qcow2: Make qiov match request size until backing file EOFKevin Wolf
If a qcow2 image has a shorter backing file and a read request to unallocated clusters goes across EOF of the backing file, the backing file sees a shortened request and the rest is filled with zeros. However, the original too long qiov was used with the shortened request. This patch makes the qiov size match the request size, avoiding a potential buffer overflow in raw-posix. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-07-09block/backup: Fix hang for unaligned image sizeKevin Wolf
When doing a block backup of an image with an unaligned size (with respect to the BACKUP_CLUSTER_SIZE), qemu would check the allocation status of sectors after the end of the image. bdrv_is_allocated() returns a result that is valid for 0 sectors in this case, so the backup job ran into an endless loop. Stop looping when seeing a result valid for 0 sectors, we're at EOF then. The test case looks somewhat unrelated at first sight because I originally tried to reproduce a different suspected bug that turned out to not exist. Still a good test case and it accidentally found this one. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2014-07-07linux-aio: implement io plug, unplug and flush io queueMing Lei
This patch implements .bdrv_io_plug, .bdrv_io_unplug and .bdrv_flush_io_queue callbacks for linux-aio Block Drivers, so that submitting I/O as a batch can be supported on linux-aio. [Unprocessed requests are completed with -EIO instead of a bogus ret value. --Stefan] Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-07raw-posix: Fix raw_getlength() to always return -errno on errorMarkus Armbruster
We got a merry mix of -1 and -errno here. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-07mirror: Fix qiov size for short requestsKevin Wolf
When mirroring an image of a size that is not a multiple of the mirror job granularity, the last request would have the right nb_sectors argument, but a qiov that is rounded up to the next multiple of the granularity. Don't do this. This fixes a segfault that is caused by raw-posix being confused by this and allocating a buffer with request length, but operating on it with qiov length. [s/Driver/Drive/ in qemu-iotests 041 as suggested by Eric --Stefan] Reported-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Tested-by: Eric Blake <eblake@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-01block: add backing-file option to block-streamJeff Cody
On some image chains, QEMU may not always be able to resolve the filenames properly, when updating the backing file of an image after a block job. For instance, certain relative pathnames may fail, or drives may have been specified originally by file descriptor (e.g. /dev/fd/???), or a relative protocol pathname may have been used. In these instances, QEMU may lack the information to be able to make the correct choice, but the user or management layer most likely does have that knowledge. With this extension to the block-stream api, the user is able to change the backing file of the active layer as part of the block-stream operation. This allows the change to be 'safe', in the sense that if the attempt to write the active image metadata fails, then the block-stream operation returns failure, without disrupting the guest. If a backing file string is not specified in the command, the backing file string to use is determined in the same manner as it was previously. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-01block: extend block-commit to accept a string for the backing fileJeff Cody
On some image chains, QEMU may not always be able to resolve the filenames properly, when updating the backing file of an image after a block commit. For instance, certain relative pathnames may fail, or drives may have been specified originally by file descriptor (e.g. /dev/fd/???), or a relative protocol pathname may have been used. In these instances, QEMU may lack the information to be able to make the correct choice, but the user or management layer most likely does have that knowledge. With this extension to the block-commit api, the user is able to change the backing file of the overlay image as part of the block-commit operation. This allows the change to be 'safe', in the sense that if the attempt to write the overlay image metadata fails, then the block-commit operation returns failure, without disrupting the guest. If the commit top is the active layer, then specifying the backing file string will be treated as an error (there is no overlay image to modify in that case). If a backing file string is not specified in the command, the backing file string to use is determined in the same manner as it was previously. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-01block/cow: Avoid use of uninitialized cow_bs in error pathPeter Maydell
Commit 25814e8987 introduced an error-exit code path which does a "goto exit" before the cow_bs variable is initialized, meaning we would call bdrv_unref() on an uninitialized variable and likely segfault. Fix this by moving the NULL-initialization to the top of the function and making the exit code path handle the case where it is NULL. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-01qemu-img create: add 'nocow' optionChunyan Liu
Add 'nocow' option so that users could have a chance to set NOCOW flag to newly created files. It's useful on btrfs file system to enhance performance. Btrfs has low performance when hosting VM images, even more when the guest in those VM are also using btrfs as file system. One way to mitigate this bad performance is to turn off COW attributes on VM files. Generally, there are two ways to turn off NOCOW on btrfs: a) by mounting fs with nodatacow, then all newly created files will be NOCOW. b) per file. Add the NOCOW file attribute. It could only be done to empty or new files. This patch tries the second way, according to the option, it could add NOCOW per file. For most block drivers, since the create file step is in raw-posix.c, so we can do setting NOCOW flag ioctl in raw-posix.c only. But there are some exceptions, like block/vpc.c and block/vdi.c, they are creating file by calling qemu_open directly. For them, do the same setting NOCOW flag ioctl work in them separately. [Fixed up 082.out due to the new 'nocow' creation option --Stefan] Signed-off-by: Chunyan Liu <cyliu@suse.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-27block: Add replaces argument to drive-mirrorBenoƮt Canet
drive-mirror will bdrv_swap the new BDS named node-name with the one pointed by replaces when the mirroring is finished. Signed-off-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Kevin Wolf <kwolf@redhat.com>