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path: root/drivers/md/dm-dust.c
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2019-05-07dm dust: Make dm_dust_init and dm_dust_exit staticYueHaibing1-2/+2
Fix sparse warnings: drivers/md/dm-dust.c:495:12: warning: symbol 'dm_dust_init' was not declared. Should it be static? drivers/md/dm-dust.c:505:13: warning: symbol 'dm_dust_exit' was not declared. Should it be static? Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-05-07dm dust: remove redundant unsigned comparison to less than zeroColin Ian King1-1/+1
Variable block is an unsigned long long hence the less than zero comparison is always false, hence it is redundant and can be removed. Addresses-Coverity: ("Unsigned compared against 0") Signed-off-by: Colin Ian King <colin.king@canonical.com> Reviewed-by: Bryan Gurney <bgurney@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-04-30dm: add dust targetBryan Gurney1-0/+515
Add the dm-dust target, which simulates the behavior of bad sectors at arbitrary locations, and the ability to enable the emulation of the read failures at an arbitrary time. This target behaves similarly to a linear target. At a given time, the user can send a message to the target to start failing read requests on specific blocks. When the failure behavior is enabled, reads of blocks configured "bad" will fail with EIO. Writes of blocks configured "bad" will result in the following: 1. Remove the block from the "bad block list". 2. Successfully complete the write. After this point, the block will successfully contain the written data, and will service reads and writes normally. This emulates the behavior of a "remapped sector" on a hard disk drive. dm-dust provides logging of which blocks have been added or removed to the "bad block list", as well as logging when a block has been removed from the bad block list. These messages can be used alongside the messages from the driver using a dm-dust device to analyze the driver's behavior when a read fails at a given time. (This logging can be reduced via a "quiet" mode, if desired.) NOTE: If the block size is larger than 512 bytes, only the first sector of each "dust block" is detected. Placing a limiting layer above a dust target, to limit the minimum I/O size to the dust block size, will ensure proper emulation of the given large block size. Signed-off-by: Bryan Gurney <bgurney@redhat.com> Co-developed-by: Joe Shimkus <jshimkus@redhat.com> Co-developed-by: John Dorminy <jdorminy@redhat.com> Co-developed-by: John Pittman <jpittman@redhat.com> Co-developed-by: Thomas Jaskiewicz <tjaskiew@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>