user/sven/linux.git/block/blk-lib.c, branch v3.9

block: account iowait time when waiting for completion of IO request

2013-02-15T15:45:07Z

Using wait_for_completion() for waiting for a IO request to be executed results in wrong iowait time accounting. For example, a system having the only task doing write() and fdatasync() on a block device can be reported being idle instead of iowaiting as it should because blkdev_issue_flush() calls wait_for_completion() which in turn calls schedule() that does not increment the iowait proc counter and thus does not turn on iowait time accounting. The patch makes block layer use wait_for_completion_io() instead of wait_for_completion() where appropriate to account iowait time correctly. Signed-off-by: Vladimir Davydov Signed-off-by: Jens Axboe

block: add plug for blkdev_issue_discard

2012-12-14T19:46:04Z

Last post of this patch appears lost, so I resend this. Now discard merge works, add plug for blkdev_issue_discard. This will help discard request merge especially for raid0 case. In raid0, a big discard request is split to small requests, and if correct plug is added, such small requests can be merged in low layer. Signed-off-by: Shaohua Li Signed-off-by: Jens Axboe

block: discard granularity might not be power of 2

2012-12-14T19:46:04Z

In MD raid case, discard granularity might not be power of 2, for example, a 4-disk raid5 has 3*chunk_size discard granularity. Correct the calculation for such cases. Reported-by: Neil Brown Signed-off-by: Shaohua Li Signed-off-by: Jens Axboe

block: Make blkdev_issue_zeroout use WRITE SAME

2012-09-20T12:31:49Z

If the device supports WRITE SAME, use that to optimize zeroing of blocks. If the device does not support WRITE SAME or if the operation fails, fall back to writing zeroes the old-fashioned way. Signed-off-by: Martin K. Petersen Acked-by: Mike Snitzer Signed-off-by: Jens Axboe

block: Implement support for WRITE SAME

2012-09-20T12:31:45Z

The WRITE SAME command supported on some SCSI devices allows the same block to be efficiently replicated throughout a block range. Only a single logical block is transferred from the host and the storage device writes the same data to all blocks described by the I/O. This patch implements support for WRITE SAME in the block layer. The blkdev_issue_write_same() function can be used by filesystems and block drivers to replicate a buffer across a block range. This can be used to efficiently initialize software RAID devices, etc. Signed-off-by: Martin K. Petersen Acked-by: Mike Snitzer Signed-off-by: Jens Axboe

block: split discard into aligned requests

2012-08-02T07:48:50Z

When a disk has large discard_granularity and small max_discard_sectors, discards are not split with optimal alignment. In the limit case of discard_granularity == max_discard_sectors, no request could be aligned correctly, so in fact you might end up with no discarded logical blocks at all. Another example that helps showing the condition in the patch is with discard_granularity == 64, max_discard_sectors == 128. A request that is submitted for 256 sectors 2..257 will be split in two: 2..129, 130..257. However, only 2 aligned blocks out of 3 are included in the request; 128..191 may be left intact and not discarded. With this patch, the first request will be truncated to ensure good alignment of what's left, and the split will be 2..127, 128..255, 256..257. The patch will also take into account the discard_alignment. At most one extra request will be introduced, because the first request will be reduced by at most granularity-1 sectors, and granularity must be less than max_discard_sectors. Subsequent requests will run on round_down(max_discard_sectors, granularity) sectors, as in the current code. Signed-off-by: Paolo Bonzini Acked-by: Vivek Goyal Tested-by: Mike Snitzer Signed-off-by: Jens Axboe

block: reorganize rounding of max_discard_sectors

2012-08-02T07:48:49Z

Mostly a preparation for the next patch. In principle this fixes an infinite loop if max_discard_sectors < granularity, but that really shouldn't happen. Signed-off-by: Paolo Bonzini Acked-by: Vivek Goyal Tested-by: Mike Snitzer Signed-off-by: Jens Axboe

block: fix patch import error in max_discard_sectors check

2011-07-23T18:34:59Z

A '!' snuck in before the unlikely, rendering it useless. Reported-by: Mike Snitzer Signed-off-by: Jens Axboe

block: eliminate potential for infinite loop in blkdev_issue_discard

2011-07-06T19:32:02Z

Due to the recently identified overflow in read_capacity_16() it was possible for max_discard_sectors to be zero but still have discards enabled on the associated device's queue. Eliminate the possibility for blkdev_issue_discard to infinitely loop. Interestingly this issue wasn't identified until a device, whose discard_granularity was 0 due to read_capacity_16 overflow, was consumed by blk_stack_limits() to construct limits for a higher-level DM multipath device. The multipath device's resulting limits never had the discard limits stacked because blk_stack_limits() will only do so if the bottom device's discard_granularity != 0. This resulted in the multipath device's limits.max_discard_sectors being 0. Signed-off-by: Mike Snitzer Signed-off-by: Jens Axboe

blkdev: Do not return -EOPNOTSUPP if discard is supported

2011-05-07T01:30:01Z

Currently we return -EOPNOTSUPP in blkdev_issue_discard() if any of the bio fails due to underlying device not supporting discard request. However, if the device is for example dm device composed of devices which some of them support discard and some of them does not, it is ok for some bios to fail with EOPNOTSUPP, but it does not mean that discard is not supported at all. This commit removes the check for bios failed with EOPNOTSUPP and change blkdev_issue_discard() to return operation not supported if and only if the device does not actually supports it, not just part of the device as some bios might indicate. This change also fixes problem with BLKDISCARD ioctl() which now works correctly on such dm devices. Signed-off-by: Lukas Czerner CC: Jens Axboe CC: Jeff Moyer Signed-off-by: Jens Axboe