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2014-09-22block: delete cow block driverStefan Hajnoczi1-433/+0
This patch removes support for the cow file format. Normally we do not break backwards compatibility but in this case there is no impact and it is the most logical option. Extraordinary claims require extraordinary evidence so I will show why removing the cow block driver is the right thing to do. The cow file format is the disk image format for Usermode Linux, a way of running a Linux system in userspace. The performance of UML was never great and it was hacky, but it enjoyed some popularity before hardware virtualization support became mainstream. QEMU's block/cow.c is supposed to read this image file format. Unfortunately the file format was underspecified: 1. Earlier Linux versions used the MAXPATHLEN constant for the backing filename field. The value of MAXPATHLEN can change, so Linux switched to a 4096 literal but QEMU has a 1024 literal. 2. Padding was not used on the header struct (both in the Linux kernel and in QEMU) so the struct layout varied across architectures. In particular, i386 and x86_64 were different due to int64_t alignment differences. Linux now uses __attribute__((packed)), QEMU does not. Therefore: 1. QEMU cow images do not conform to the Linux cow image file format. 2. cow images cannot be shared between different host architectures. This means QEMU cow images are useless and QEMU has not had bug reports from users actually hitting these issues. Let's get rid of this thing, it serves no purpose and no one will be affected. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-id: 1410877464-20481-1-git-send-email-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-12block: round up file size to nearest sectorHu Tao1-1/+2
Currently the file size requested by user is rounded down to nearest sector, causing the actual file size could be a bit less than the size user requested. Since some formats (like qcow2) record virtual disk size in bytes, this can make the last few bytes cannot be accessed. This patch fixes it by rounding up file size to nearest sector so that the actual file size is no less than the requested file size. Signed-off-by: Hu Tao <hutao@cn.fujitsu.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-07-01block/cow: Avoid use of uninitialized cow_bs in error pathPeter Maydell1-3/+4
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>
2014-06-26block: Catch backing files assigned to non-COW driversKevin Wolf1-0/+1
Since we parse backing.* options to add a backing file from the command line when the driver didn't assign one, it has been possible to have a backing file for e.g. raw images (it just was never accessed). This is obvious nonsense and should be rejected. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2014-06-16cleanup QEMUOptionParameterChunyan Liu1-2/+2
Now that all backend drivers are using QemuOpts, remove all QEMUOptionParameter related codes. Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com> Signed-off-by: Chunyan Liu <cyliu@suse.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-16cow.c: replace QEMUOptionParameter with QemuOptsChunyan Liu1-28/+26
Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com> Signed-off-by: Chunyan Liu <cyliu@suse.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-16change block layer to support both QemuOpts and QEMUOptionParamterChunyan Liu1-1/+1
Change block layer to support both QemuOpts and QEMUOptionParameter. After this patch, it will change backend drivers one by one. At the end, QEMUOptionParameter will be removed and only QemuOpts is kept. Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com> Signed-off-by: Chunyan Liu <cyliu@suse.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-04-30block: Use correct width in format stringsMax Reitz1-1/+1
Instead of blindly relying on a normal integer having a width of 32 bits (which is a pretty good assumption, but we should not rely on it if there is no need), use the correct format string macros. This does not touch DEBUG output. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-02-21block: do not abuse EMEDIUMTYPEPaolo Bonzini1-1/+2
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>
2014-02-21cow: correctly propagate errorsPaolo Bonzini1-5/+3
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 Reitz1-2/+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>
2014-01-22block: Allow reference for bdrv_file_open()Max Reitz1-1/+2
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>
2013-11-29COW: Extend checking allocated bits to beyond one sectorCharlie Shepherd1-10/+26
cow_co_is_allocated() only checks one sector's worth of allocated bits before returning. This is allowed but (slightly) inefficient, so extend it to check all of the file's metadata sectors. Signed-off-by: Charlie Shepherd <charlie@ctshepherd.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> [kwolf: silenced compiler warning (-Wmaybe-uninitialized for changed)] Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-29COW: Speed up writesCharlie Shepherd1-38/+50
Process a whole sector's worth of COW bits by reading a sector, setting the bits after skipping any already set bits, then writing it out again. Make sure we only flush once before writing metadata, and only if we need to write metadata. Signed-off-by: Charlie Shepherd <charlie@ctshepherd.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-09-12block: Error parameter for create functionsMax Reitz1-1/+3
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 Reitz1-1/+4
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 Reitz1-1/+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>
2013-09-06block: return get_block_status data and flags for formatsPaolo Bonzini1-1/+7
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 Bonzini1-1/+7
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 Bonzini1-1/+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>
2013-09-06cow: do not call bdrv_co_is_allocatedPaolo Bonzini1-1/+1
As we change bdrv_is_allocated to gather more information from bs and bs->file, it will become a bit slower. It is still appropriate for online jobs, but not for reads/writes. Call the internal function instead. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-09-06cow: make writes go at a less indecent speedPaolo Bonzini1-3/+16
Only sync once per write, rather than once per sector. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-09-06cow: make reads go at a decent speedPaolo Bonzini1-22/+32
Do not do two reads for each sector; load each sector of the bitmap and use bitmap operations to process it. Writes are still dog slow! 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>
2013-06-28block: change default of .has_zero_init to 0Peter Lieven1-0/+1
.has_zero_init defaults to 1 for all formats and protocols. this is a dangerous default since this means that all new added drivers need to manually overwrite it to 0 if they do not ensure that a device is zero initialized after bdrv_create(). if a driver needs to explicitly set this value to 1 its easier to verify the correctness in the review process. during review of the existing drivers it turned out that ssh and gluster had a wrong default of 1. both protocols support host_devices as backend which are not by default zero initialized. this wrong assumption will lead to possible corruption if qemu-img convert is used to write to such a backend. vpc and vmdk also defaulted to 1 altough they support fixed respectively flat extends. this has to be addresses in separate patches. both formats as well as the mentioned ssh and gluster are turned to the default of 0 with this patch for safety. a similar problem with the wrong default existed for iscsi most likely because the driver developer did oversee the default value of 1. Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-03-22block: Add options QDict to bdrv_file_open() prototypesKevin Wolf1-1/+1
The new parameter is unused yet. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2013-03-15block: Add options QDict to .bdrv_open()Kevin Wolf1-1/+1
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-01-25block: Use error code EMEDIUMTYPE for wrong format in some block driversStefan Weil1-1/+1
This improves error reports for bochs, cow, qcow, qcow2, qed and vmdk when a file with the wrong format is selected. Signed-off-by: Stefan Weil <sw@weilnetz.de> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-12-19misc: move include files to include/qemu/Paolo Bonzini1-1/+1
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-12-19block: move include files to include/block/Paolo Bonzini1-1/+1
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-04-19block: Fix spelling in comment (ineffcient -> inefficient)Stefan Weil1-1/+1
Signed-off-by: Stefan Weil <sw@weilnetz.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-05block: push recursive flushing up from driversPaolo Bonzini1-6/+0
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-15block/cow: Return real error codeLi Zhi Hui1-15/+29
Signed-off-by: Li Zhi Hui <zhihuili@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05Merge remote-tracking branch 'kwolf/for-anthony' into stagingAnthony Liguori1-24/+22
2011-12-05cow: use bdrv_co_is_allocated()Stefan Hajnoczi1-3/+3
Now that bdrv_co_is_allocated() is available we can use it instead of the synchronous bdrv_is_allocated() interface. This is a follow-up that Kevin Wolf <kwolf@redhat.com> pointed out after applying the series that introduces bdrv_co_is_allocated(). It is safe to make cow_read() a coroutine_fn because its only caller is a coroutine_fn. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05cow: convert to .bdrv_co_is_allocated()Stefan Hajnoczi1-4/+4
The cow block driver does not keep internal state for cluster lookups. This means it is safe to perform cluster lookups in coroutine context without risk of race conditions that corrupt internal state. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05block: Use bdrv functions to replace file operation in cow.cLi Zhi Hui1-18/+16
Since common file operation functions lack of error detection, so change them to bdrv series functions. Signed-off-by: Li Zhi Hui <zhihuili@linux.vnet.ibm.com> Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-02fix spelling in block sub directoryDong Xu Wang1-1/+1
Cc: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2011-11-11block: Rename bdrv_co_flush to bdrv_co_flush_to_diskKevin Wolf1-10/+12
There are two different types of flush that you can do: Flushing one level up to the OS (i.e. writing data to the host page cache) or flushing it all the way down to the disk. The existing functions flush to the disk, reflect this in the function name. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-21block: change flush to co_flushPaolo Bonzini1-3/+3
Since coroutine operation is now mandatory, convert all bdrv_flush implementations to coroutines. For qcow2, this means taking the lock. Other implementations are simpler and just forward bdrv_flush to the underlying protocol, so they can avoid the lock. The bdrv_flush callback is then unused and can be eliminated. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-21block: take lock around bdrv_write implementationsPaolo Bonzini1-1/+12
This does the first part of the conversion to coroutines, by wrapping bdrv_write implementations to take the mutex. Drivers that implement bdrv_write rather than bdrv_co_writev can then benefit from asynchronous operation (at least if the underlying protocol supports it, which is not the case for raw-win32), even though they still operate with a bounce buffer. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-21block: take lock around bdrv_read implementationsPaolo Bonzini1-1/+12
This does the first part of the conversion to coroutines, by wrapping bdrv_read implementations to take the mutex. Drivers that implement bdrv_read rather than bdrv_co_readv can then benefit from asynchronous operation (at least if the underlying protocol supports it, which is not the case for raw-win32), even though they still operate with a bounce buffer. raw-win32 does not need the lock, because it cannot yield. nbd also doesn't probably, but better be safe. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-21block: add a CoMutex to synchronous read driversPaolo Bonzini1-0/+2
The big conversion of bdrv_read/write to coroutines caused the two homonymous callbacks in BlockDriver to become reentrant. It goes like this: 1) bdrv_read is now called in a coroutine, and calls bdrv_read or bdrv_pread. 2) the nested bdrv_read goes through the fast path in bdrv_rw_co_entry; 3) in the common case when the protocol is file, bdrv_co_do_readv calls bdrv_co_readv_em (and from here goes to bdrv_co_io_em), which yields until the AIO operation is complete; 4) if bdrv_read had been called from a bottom half, the main loop is free to iterate again: a device model or another bottom half can then come and call bdrv_read again. This applies to all four of read/write/flush/discard. It would also apply to is_allocated, but it is not used from within coroutines: besides qemu-img.c and qemu-io.c, which operate synchronously, the only user is the monitor. Copy-on-read will introduce a use in the block layer, and will require converting it. The solution is "simply" to convert all drivers to coroutines! We just need to add a CoMutex that is taken around affected operations. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-11-04block: Allow bdrv_flush to return errorsKevin Wolf1-2/+2
This changes bdrv_flush to return 0 on success and -errno in case of failure. It's a requirement for implementing proper error handle in users of bdrv_flush. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2010-06-22cow: Use bdrv_(p)write_sync for metadata writesKevin Wolf1-9/+11
Use bdrv_(p)write_sync to ensure metadata integrity in case of a crash. While at it, correct the wrong usage of errno. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-06-15cow: use qemu block APIChristoph Hellwig1-26/+13
Use bdrv_pwrite to access the backing device instead of pread, and convert the driver to implementing the bdrv_open method which gives it an already opened BlockDriverState for the underlying device. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-06-15cow: stop using mmapChristoph Hellwig1-37/+61
We don't have an equivalent to mmap in the qemu block API, so read and write the bitmap directly. At least in the dumb implementation added in this patch this is a lot less efficient, but it means cow can also work on windows, and over nbd or curl. And it fixes qemu-iotests testcase 012 which did not work properly due to issues with read-only mmap access. In addition we can also get rid of the now unused get_mmap_addr function. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-06-15cow: use pread/pwriteChristoph Hellwig1-5/+5
Use pread/pwrite instead of lseek + read/write in preparation of using the qemu block API. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-03block: Open the underlying image file in generic codeKevin Wolf1-1/+1
Format drivers shouldn't need to bother with things like file names, but rather just get an open BlockDriverState for the underlying protocol. This patch introduces this behaviour for bdrv_open implementation. For protocols which need to access the filename to open their file/device/connection/... a new callback bdrv_file_open is introduced which doesn't get an underlying file opened. For now, also some of the more obscure formats use bdrv_file_open because they open() the file themselves instead of using the block.c functions. They need to be fixed in later patches. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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