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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>
2013-09-06block: use bdrv_has_zero_init to return BDRV_BLOCK_ZEROPaolo Bonzini1-1/+10
Alternatively, this could use a "discard zeroes data" flag returned by bdrv_get_info. 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: define get_block_status return valuePaolo Bonzini1-2/+8
Define the return value of get_block_status. Bits 0, 1, 2 and 9-62 are valid; bit 63 (the sign bit) is reserved for errors. Bits 3-8 are left for future extensions. The return code is compatible with the old is_allocated API: if a driver only returns 0 or 1 (aka BDRV_BLOCK_DATA) like is_allocated used to, clients of is_allocated will not have any change in behavior. Still, we will return more precise information in the next patches and the new definition of bdrv_is_allocated is already prepared for this. 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 Bonzini1-20/+26
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: make bdrv_has_zero_init return false for copy-on-write-imagesPaolo Bonzini1-0/+5
This helps implementing is_allocated on top of get_block_status. 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 Bonzini1-2/+5
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: remove bdrv_is_allocated_above/bdrv_co_is_allocated_above distinctionPaolo Bonzini1-42/+4
Now that bdrv_is_allocated detects coroutine context, the two can use the same code. 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: do not use ->total_sectors in bdrv_co_is_allocatedPaolo Bonzini1-1/+7
This is more robust when the device has removable media. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-09-06block: make bdrv_co_is_allocated staticPaolo Bonzini1-9/+15
bdrv_is_allocated can detect coroutine context and go through a fast path, similar to other block layer functions. 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: keep bs->total_sectors up to date even for growable block devicesPaolo Bonzini1-1/+4
If a BlockDriverState is growable, after every write we need to check if bs->total_sectors might have changed. With this change, bdrv_getlength does not need anymore a system call. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-09-06block: make bdrv_delete() staticFam Zheng1-11/+12
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>
2013-09-06block: implement reference count for BlockDriverStateFam Zheng1-0/+21
Introduce bdrv_ref/bdrv_unref to manage the lifecycle of BlockDriverState. They are unused for now but will used to replace bdrv_delete() later. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-09-06block: Enable the new throttling code in the block layer.Benoît Canet1-243/+95
Signed-off-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-08-30block: Remove redundant assertionKevin Wolf1-1/+0
The failing condition is checked immediately before the assertion, so keeping the assertion is kind of redundant. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-08-22aio / timers: Switch entire codebase to the new timer APIAlex Bligh1-7/+7
This is an autogenerated patch using scripts/switch-timer-api. Switch the entire code base to using the new timer API. Note this patch may introduce some line length issues. Signed-off-by: Alex Bligh <alex@alex.org.uk> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-08-22block: Produce zeros when protocols reading beyond end of fileMORITA Kazutaka1-1/+29
While Asias is debugging an issue creating qcow2 images on top of non-file protocols. It boils down to this example using NBD: $ qemu-io -c 'open -g nbd+unix:///?socket=/tmp/nbd.sock' -c 'read -v 0 512' Notice the open -g option to set bs->growable. This means you can read/write beyond end of file. Reading beyond end of file is supposed to produce zeroes. We rely on this behavior in qcow2_create2() during qcow2 image creation. We create a new file and then write the qcow2 header structure using bdrv_pwrite(). Since QCowHeader is not a multiple of sector size, block.c first uses bdrv_read() on the empty file to fetch the first sector (should be all zeroes). Here is the output from the qemu-io NBD example above: $ qemu-io -c 'open -g nbd+unix:///?socket=/tmp/nbd.sock' -c 'read -v 0 512' 00000000: ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ................ 00000010: ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ................ 00000020: ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ................ ... We are not zeroing the buffer! As a result qcow2 image creation on top of protocols is not guaranteed to work even when file creation is supported by the protocol. [Adapted this patch to use bs->zero_beyond_eof. -- Stefan] Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp> Signed-off-by: Asias He <asias@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-08-22block: Introduce bs->zero_beyond_eofAsias He1-0/+2
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>
2013-08-19block: stop relying on io_flush() in bdrv_drain_all()Stefan Hajnoczi1-10/+35
If a block driver has no file descriptors to monitor but there are still active requests, it can return 1 from .io_flush(). This is used to spin during synchronous I/O. Stop relying on .io_flush() and instead check QLIST_EMPTY(&bs->tracked_requests) to decide whether there are active requests. This is the first step in removing .io_flush() so that event loops no longer need to have the concept of synchronous I/O. Eventually we may be able to kill synchronous I/O completely by running everything in a coroutine, but that is future work. Note this patch moves bs->throttled_reqs initialization to bdrv_new() so that bdrv_requests_pending(bs) can safely access it. In practice bs is g_malloc0() so the memory is already zeroed but it's safer to initialize the queue properly. We also need to fix up block/stream.c:close_unused_images() to prevent traversing a dangling pointer while it rearranges the backing file chain. This is necessary since the new bdrv_drain_all() traverses the backing file chain. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-08-19block: ensure bdrv_drain_all() works during bdrv_delete()Stefan Hajnoczi1-2/+2
In bdrv_delete() make sure to call bdrv_make_anon() *after* bdrv_close() so that the device is still seen by bdrv_drain_all() when iterating bdrv_states. Cc: qemu-stable@nongnu.org Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-07-29block: Repair the throttling code.Benoît Canet1-4/+3
The throttling code was segfaulting since commit 02ffb504485f0920cfc75a0982a602f824a9a4f4 because some qemu_co_queue_next caller does not run in a coroutine. qemu_co_queue_do_restart assume that the caller is a coroutinne. As suggested by Stefan fix this by entering the coroutine directly. Also make sure like suggested that qemu_co_queue_next() and qemu_co_queue_restart_all() can be called only in coroutines. Signed-off-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-07-26block: Allow "driver" option on the top levelKevin Wolf1-0/+7
This is traditionally -drive format=..., which is now translated into the new driver option. This gives us a more consistent way to select the driver of BlockDriverStates that can be used in QMP context, too. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2013-07-19block: fix bdrv_read_unthrottled()Peter Lieven1-1/+1
Signed-off-by: Peter Lieven <pl@kamp.de> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-07-19block: add bdrv_write_zeroes()Peter Lieven1-8/+19
Signed-off-by: Peter Lieven <pl@kamp.de> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-07-15block: Add return value for bdrv_flush_all()Kevin Wolf1-2/+8
bdrv_flush() can fail, and bdrv_flush_all() should return an error as well if this happens for a block device. It returns the first error return now, but still at least tries to flush the remaining devices even in error cases. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-07-15block: Don't parse protocol from file.filenameKevin Wolf1-5/+12
One of the major reasons for doing something new for -blockdev and blockdev-add was that the old block layer code parses filenames instead of just taking them literally. So we should really leave it untouched when it's passing using the new interfaces (like -drive file.filename=...). This allows opening relative file names that contain a colon. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2013-07-05block: fix bdrv_flush() ordering in bdrv_close()Stefan Hajnoczi1-2/+3
Since 80ccf93b we flush the block device during close. The bdrv_drain_all() call should come before bdrv_flush() to ensure guest write requests have completed. Otherwise we may miss pending writes when flushing. Call bdrv_drain_all() again for safety as the final step after bdrv_flush(). This should not be necessary but we can be paranoid here in case bdrv_flush() left I/O pending. Cc: qemu-stable@nongnu.org Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
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