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path: root/block/blklogwrites.c
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2018-07-05block/blklogwrites: Add an option for the update interval of the log superblockAri Sundholm
This is a way to ensure that the log superblock is periodically updated. Before, this was only done on flush requests, which may not be enough if the VM exits abnormally, omitting the final flush. The default interval is 4096 write requests. Signed-off-by: Ari Sundholm <ari@tuxera.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-07-05block/blklogwrites: Add an option for appending to an old logAri Sundholm
Suggested by Kevin Wolf. May be useful when testing multiple batches of writes or doing long-term testing involving restarts of the VM. Signed-off-by: Ari Sundholm <ari@tuxera.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-07-05block/blklogwrites: Change log_sector_size from int64_t to uint64_tAri Sundholm
This was a simple oversight when working on intermediate versions of the original patch which introduced blklogwrites. Signed-off-by: Ari Sundholm <ari@tuxera.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-07-05block: Add blklogwritesAapo Vienamo
Implements a block device write logging system, similar to Linux kernel device mapper dm-log-writes. The write operations that are performed on a block device are logged to a file or another block device. The write log format is identical to the dm-log-writes format. Currently, log markers are not supported. This functionality can be used for crash consistency and fs consistency testing. By implementing it in qemu, tests utilizing write logs can be be used to test non-Linux drivers and older kernels. The driver accepts an optional parameter to set the sector size used for logging. This makes the driver require all requests to be aligned to this sector size and also makes offsets and sizes of writes in the log metadata to be expressed in terms of this value (the log format has a granularity of one sector for offsets and sizes). This allows accurate logging of writes to guest block devices that have unusual sector sizes. The implementation is based on the blkverify and blkdebug block drivers. Signed-off-by: Aapo Vienamo <aapo@tuxera.com> Signed-off-by: Ari Sundholm <ari@tuxera.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>