Commit Graph

6 Commits

Author SHA1 Message Date
Fam Zheng 0b9fd3f467 block: Use BdrvChild to discard
Other I/O functions are already using a BdrvChild pointer in the API, so
make discard do the same. It makes it possible to initiate the same
permission checks before doing I/O, and much easier to share the
helper functions for this, which will be added and used by write,
truncate and copy range paths.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-07-10 16:01:52 +02:00
Ari Sundholm ba814c82bb block/blklogwrites: Make sure the log sector size is not too small
The sector size needs to be large enough to accommodate the data
structures for the log super block and log write entries. This was
previously not properly checked, which made it possible to cause
QEMU to badly misbehave.

Signed-off-by: Ari Sundholm <ari@tuxera.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-07-10 13:17:48 +02:00
Ari Sundholm 1dce698ea8 block/blklogwrites: Add an option for the update interval of the log superblock
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>
2018-07-05 10:50:21 +02:00
Ari Sundholm 0878b3c113 block/blklogwrites: Add an option for appending to an old log
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>
2018-07-05 10:50:20 +02:00
Ari Sundholm 2dacaf7c82 block/blklogwrites: Change log_sector_size from int64_t to uint64_t
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>
2018-07-05 10:50:20 +02:00
Aapo Vienamo bfcc224e3c block: Add blklogwrites
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>
2018-07-05 10:29:19 +02:00