path: root/block/elevator.c
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authorIlya Dryomov <>2017-10-16 15:59:10 +0200
committerJens Axboe <>2017-10-25 12:28:23 -0600
commitd5ce4c31d6df518dd8f63bbae20d7423c5018a6c (patch)
treea55c96e7b9952484083fdaa608a387d2929cdcb6 /block/elevator.c
parent425a4dba7953e35ffd096771973add6d2f40d2ed (diff)
block: cope with WRITE ZEROES failing in blkdev_issue_zeroout()
sd_config_write_same() ignores ->max_ws_blocks == 0 and resets it to permit trying WRITE SAME on older SCSI devices, unless ->no_write_same is set. Because REQ_OP_WRITE_ZEROES is implemented in terms of WRITE SAME, blkdev_issue_zeroout() may fail with -EREMOTEIO: $ fallocate -zn -l 1k /dev/sdg fallocate: fallocate failed: Remote I/O error $ fallocate -zn -l 1k /dev/sdg # OK $ fallocate -zn -l 1k /dev/sdg # OK The following calls succeed because sd_done() sets ->no_write_same in response to a sense that would become BLK_STS_TARGET/-EREMOTEIO, causing __blkdev_issue_zeroout() to fall back to generating ZERO_PAGE bios. This means blkdev_issue_zeroout() must cope with WRITE ZEROES failing and fall back to manually zeroing, unless BLKDEV_ZERO_NOFALLBACK is specified. For BLKDEV_ZERO_NOFALLBACK case, return -EOPNOTSUPP if sd_done() has just set ->no_write_same thus indicating lack of offload support. Fixes: c20cfc27a473 ("block: stop using blkdev_issue_write_same for zeroing") Cc: Hannes Reinecke <> Reviewed-by: Christoph Hellwig <> Reviewed-by: Martin K. Petersen <> Signed-off-by: Ilya Dryomov <> Signed-off-by: Jens Axboe <>
Diffstat (limited to 'block/elevator.c')
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