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2013-12-06block: clean up bdrv_drain_all() throttling commentsStefan Hajnoczi1-6/+1
Since cc0681c45430a1f1a4c2d06e9499b7775afc9a18 ("block: Enable the new throttling code in the block layer.") bdrv_drain_all() no longer spins. The code used to look as follows: do { busy = qemu_aio_wait(); /* FIXME: We do not have timer support here, so this is effectively * a busy wait. */ QTAILQ_FOREACH(bs, &bdrv_states, list) { while (qemu_co_enter_next(&bs->throttled_reqs)) { busy = true; } } } while (busy); Note that throttle requests are kicked but I/O throttling limits are still in effect. The loop spins until the vm_clock time allows the request to make progress and complete. The new throttling code introduced bdrv_start_throttled_reqs(). This function not only kicks throttled requests but also temporarily disables throttling so requests can run. The outdated FIXME comment can be removed. Also drop the busy = true assignment since we overwrite it immediately afterwards. Reviewed-by: Alex Bligh <alex@alex.org.uk> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-04block: Close backing file early in bdrv_img_createMax Reitz1-4/+4
Leaving the backing file open although it is not needed anymore can cause problems if it is opened through a block driver which allows exclusive access only and if the create function of the block driver used for the top image (the one being created) tries to close and reopen the image file (which will include opening the backing file a second time). In particular, this will happen with a backing file opened through qemu-nbd and using qcow2 as the top image file format (which reopens the image to flush it to disk). In addition, the BlockDriverState in bdrv_img_create() is used for the backing file only; it should therefore be made local to the respective block. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03block: make bdrv_co_do_write_zeroes stricter in producing aligned requestsPaolo Bonzini1-12/+23
Right now, bdrv_co_do_write_zeroes will only try to align the beginning of the request. However, it is simpler for many formats to expect the block layer to separate both the head *and* the tail. This makes sure that the format's bdrv_co_write_zeroes function will be called with aligned sector_num and nb_sectors for the bulk of the request. 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: handle ENOTSUP from discard in generic codePaolo Bonzini1-1/+1
Similar to write_zeroes, let the generic code receive a ENOTSUP for discard operations. Since bdrv_discard has advisory semantics, we can just swallow the error. 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: add bdrv_aio_write_zeroesPaolo Bonzini1-0/+11
This will be used by the SCSI layer. 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: add flags argument to bdrv_co_write_zeroes tracepointPaolo Bonzini1-1/+1
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: add flags to BlockRequestPaolo Bonzini1-6/+11
This lets bdrv_co_do_rw receive flags, so that it can be used for zero writes. 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: generalize BlockLimits handling to cover bdrv_aio_discard tooPaolo Bonzini1-39/+41
bdrv_co_discard is only covering drivers which have a .bdrv_co_discard() implementation, but not those with .bdrv_aio_discard(). Not very nice, and easy to avoid. Suggested-by: Kevin Wolf <kwolf@redhat.com> 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>
2013-11-29block: Enable BDRV_O_SNAPSHOT with driver-specific optionsKevin Wolf1-26/+21
In the case of snapshot=on, don't rely on the backing file path in the temporary image any more, but override the backing file with the given set of options. This way, block drivers that don't use a file name can be accessed with snapshot=on, for example: -drive file.driver=nbd,file.host=localhost,snapshot=on Which becomes internally something like: file.filename=/tmp/vl.AWQZCu,backing.file.driver=nbd,backing.file.host=localhost Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-29blkdebug: add "remove_break" commandFam Zheng1-0/+13
This adds "remove_break" command which is the reverse of blkdebug command "break": it removes all breakpoints with given tag and resumes all the requests. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-29qapi: Change BlockDirtyInfo to listFam Zheng1-0/+20
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 Zheng1-34/+49
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/get_block_status: fix BDRV_BLOCK_ZERO for unallocated blocksPeter Lieven1-2/+2
this patch does 2 things: a) only do additional call outs if BDRV_BLOCK_ZERO is not already set. b) use the newly introduced bdrv_unallocated_blocks_are_zero() to return the zero state of an unallocated block. the used callout to bdrv_has_zero_init() is only valid right after bdrv_create. 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: introduce bdrv_make_zeroPeter Lieven1-0/+37
this patch adds a call to completely zero out a block device. the operation is sped up by checking the block status and only writing zeroes to the device if they currently do not return zeroes. optionally the zero writing can be sped up by setting the flag BDRV_REQ_MAY_UNMAP to emulate the zero write by unmapping if the driver supports it. Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28block: honour BlockLimits in bdrv_co_discardPeter Lieven1-1/+36
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: honour BlockLimits in bdrv_co_do_write_zeroesPeter Lieven1-16/+49
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 wrappers for logical block provisioning informationPeter Lieven1-0/+30
This adds 2 wrappers to read the unallocated_blocks_are_zero and can_write_zeroes_with_unmap info from the BDI. The wrappers are required to check for the existence of a backing_hd and if the devices are opened with the correct flags. 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: introduce BDRV_REQ_MAY_UNMAP request flagPeter Lieven1-0/+4
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 Lieven1-9/+11
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: make BdrvRequestFlags publicPeter Lieven1-5/+0
Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-15block: Fail if requested driver is not availableKevin Wolf1-0/+5
If an explicit driver option is present, but doesn't specify a valid driver, then bdrv_open() should fail instead of probing the format. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-14block: Print its file name if backing file opening failedFam Zheng1-1/+3
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>
2013-11-08block: Round up total_sectorsFam Zheng1-1/+1
Since b94a2610, bdrv_getlength() is omitted when probing image. VMDK monolithicFlat is broken by that because a file < 512 bytes can't be read with its total_sectors truncated to 0. This patch round up the size to BDRV_SECTOR_SIZE, when a image size is not sector aligned. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-07block: Save errno before error_setg_errnoMax Reitz1-1/+1
error_setg_errno() may overwrite errno; therefore, its value should be read before calling that function and not afterwards. 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: Stefan Hajnoczi <stefanha@redhat.com>
2013-10-29block: Avoid unecessary drv->bdrv_getlength() callsKevin Wolf1-3/+4
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>
2013-10-29block: Disable BDRV_O_COPY_ON_READ for the backing fileThibaut LAURENT1-1/+2
Since commit 0ebd24e0a203cf2852c310b59fbe050190dc6c8c, bdrv_open_common will throw an error when trying to open a file read-only with the BDRV_O_COPY_ON_READ flag set. Although BDRV_O_RDWR is unset for the backing files, BDRV_O_COPY_ON_READ is still passed on if copy-on-read was requested for the drive. Let's unset this flag too before opening the backing file, or bdrv_open_common will fail. Signed-off-by: Thibaut LAURENT <thibaut.laurent@gmail.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-28block: Don't copy backing file name on errorMax Reitz1-2/+2
bdrv_open_backing_file() tries to copy the backing file name using pstrcpy directly after calling bdrv_open() to open the backing file without checking whether that was actually successful. If it was not, ps->backing_hd->file will probably be NULL and qemu will crash. Fix this by moving pstrcpy after checking whether bdrv_open() succeeded. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Amos Kong <kongjianjun@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-11blockdev: Don't disable COR automatically with blockdev-addKevin Wolf1-2/+7
If a read-only device is configured with copy-on-read=on, the old code only prints a warning and automatically disables copy on read. Make it a real error for blockdev-add. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2013-10-11block: Improve driver whitelist checksKevin Wolf1-3/+7
The main intent of this patch is to consolidate the whitelist checks to a single point in the code instead of spreading it everywhere. This adds a nicer error message for read-only whitelisting, too, in places where it was still missing. The patch also contains a bonus bug fix: By finding the format first in bdrv_open() and then independently checking against the whitelist only later, we avoid the case that use of a non-whitelisted format results in probing rather than an error message. Previously, this could happen when using the driver=... option. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com>
2013-10-11block: Add BlockDriver.bdrv_check_ext_snapshot.Benoît Canet1-0/+19
This field is used by blkverify to disable external snapshots creation. It will also be used by block filters like quorum to disable external snapshot creation. Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-11block/get_block_status: avoid redundant callouts on raw devicesPeter Lieven1-0/+6
if a raw device like an iscsi target or host device is used the current implementation makes a second call out to get the block status of bs->file. Signed-off-by: Peter Lieven <pl@kamp.de> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-11block: Add bdrv_get_specific_infoMax Reitz1-0/+9
Add a function for retrieving an ImageInfoSpecific object from a block driver. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-10-07block: use correct filenameDunrong Huang1-2/+2
The content filename point to may be erased by qemu_opts_absorb_qdict() in raw_open_common() in drv->bdrv_file_open() So it's better to use bs->filename. Signed-off-by: Dunrong Huang <riegamaths@gmail.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-10-02block: use correct filename for error reportDunrong Huang1-2/+2
The content filename point to will be erased by qemu_opts_absorb_qdict() in raw_open_common() in drv->bdrv_file_open() So it's better to use bs->filename. Signed-off-by: Dunrong Huang <riegamaths@gmail.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-09-26block: use DIV_ROUND_UP in bdrv_co_do_readvFam Zheng1-1/+1
Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-25qdict: Extract qdict_extract_subqdictBenoît Canet1-21/+2
Signed-off-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-25block: introduce BlockDriver.bdrv_needs_filename to enable some drivers.Benoît Canet1-2/+2
Some drivers will have driver specifics options but no filename. This new bool allow the block layer to treat them correctly. The .bdrv_needs_filename is set in drivers not having .bdrv_parse_filename and not having .bdrv_open. The first exception to this rule will be the quorum driver. Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-25block/get_block_status: avoid segfault if there is no backing_hdPeter Lieven1-1/+1
Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-25block/get_block_status: set *pnum = 0 on errorPeter Lieven1-0/+1
if the call is invoked through bdrv_is_allocated the caller might expect *pnum = 0 on error. however, a new implementation of bdrv_get_block_status might only return a negative exit value on error while keeping *pnum untouched. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-25block: fix backing file overridingFam Zheng1-2/+5
Providing backing.file.filename doesn't override backing file as expected: $ x86_64-softmmu/qemu-system-x86_64 -drive \ file=/tmp/child.qcow2,backing.file.filename=/tmp/fake.qcow2 qemu-system-x86_64: -drive \ file=/tmp/child.qcow2,backing.file.filename=/tmp/fake.qcow2: could not open disk image /tmp/child.qcow2: Can't specify 'file' and 'filename' options at the same time With $ qemu-img info /tmp/child.qcow2 image: /tmp/child.qcow2 file format: qcow2 virtual size: 1.0G (1073741824 bytes) disk size: 196K cluster_size: 65536 backing file: /tmp/fake.qcow2 This fixes it by calling bdrv_get_full_backing_filename only if backing.file.filename is not provided. Also save the backing file name to bs->backing_file so the information is correct with HMP "info block". Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-20block: don't lose data from last incomplete sectorFam Zheng1-1/+1
To read the last sector that is not aligned to sector boundary, current code for growable backends, since commit 893a8f6 "block: Produce zeros when protocols reading beyond end of file", drops the data and directly returns zeroes. That is incorrect. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-09-12block: Error parameter for create functionsMax Reitz1-24/+56
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 Reitz1-36/+64
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/+1
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/+2
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>
2013-09-12block: Image file option amendmentMax Reitz1-0/+8
This patch adds the "amend" option to qemu-img which allows changing image options on existing image files. It also adds the generic bdrv implementation which is basically just a wrapper for the image format specific function. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-06block: look for zero blocks in bs->filePaolo Bonzini1-1/+15
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: add default get_block_status implementation for protocolsPaolo Bonzini1-1/+5
Protocols return raw data, so you can assume the offsets to pass through unchanged. 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: return BDRV_BLOCK_ZERO past end of backing filePaolo Bonzini1-2/+10
If the sectors are unallocated and we are past the end of the backing file, they will read as zero. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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