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2011-10-21block: take lock around bdrv_read implementationsPaolo Bonzini
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 Bonzini
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>
2011-08-20Use glib memory allocation and free functionsAnthony Liguori
qemu_malloc/qemu_free no longer exist after this commit. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-05-17bochs: use qemu block APIChristoph Hellwig
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>
2010-05-17bochs: use preadChristoph Hellwig
Use pread instead of lseek + read 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 Wolf
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>
2010-01-26Read-only device changed to opens it's file for read-only.Naphtali Sprei
Signed-off-by: Naphtali Sprei <nsprei@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-12-25block/bochs: improve format checkingBlue Swirl
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2009-12-25block/bochs.c: fix warning with _FORTIFY_SOURCEKirill A. Shutemov
CC block/bochs.o cc1: warnings being treated as errors block/bochs.c: In function 'seek_to_sector': block/bochs.c:202: error: ignoring return value of 'read', declared with attribute warn_unused_result make: *** [block/bochs.o] Error 1 Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2009-05-14Move block drivers into their own directoryAnthony Liguori
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>