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alistair23-linux/drivers/block/drbd
Martin K. Petersen d93ba7a5a9 block: Add discard flag to blkdev_issue_zeroout() function
blkdev_issue_discard() will zero a given block range. This is done by
way of explicit writing, thus provisioning or allocating the blocks on
disk.

There are use cases where the desired behavior is to zero the blocks but
unprovision them if possible. The blocks must deterministically contain
zeroes when they are subsequently read back.

This patch adds a flag to blkdev_issue_zeroout() that provides this
variant. If the discard flag is set and a block device guarantees
discard_zeroes_data we will use REQ_DISCARD to clear the block range. If
the device does not support discard_zeroes_data or if the discard
request fails we will fall back to first REQ_WRITE_SAME and then a
regular REQ_WRITE.

Also update the callers of blkdev_issue_zero() to reflect the new flag
and make sb_issue_zeroout() prefer the discard approach.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-01-21 10:41:46 -07:00
..
Kconfig drbd: update Kconfig to match current dependencies 2012-12-06 13:08:29 +01:00
Makefile drbd: debugfs: add basic hierarchy 2014-07-10 18:35:16 +02:00
drbd_actlog.c drbd: Minor cleanups 2014-11-10 09:27:30 -07:00
drbd_bitmap.c drbd: Use consistent names for all the bi_end_io callbacks 2014-09-11 08:41:29 -06:00
drbd_debugfs.c kill f_dentry uses 2014-11-19 13:01:25 -05:00
drbd_debugfs.h drbd: debugfs: add basic hierarchy 2014-07-10 18:35:16 +02:00
drbd_int.h drbd: Remove an useless copy of kernel_setsockopt() 2014-11-10 09:27:43 -07:00
drbd_interval.c drbd: use RB_DECLARE_CALLBACKS() to define augment callbacks 2014-09-18 09:00:17 -06:00
drbd_interval.h drbd: application writes may set-in-sync in protocol != C 2014-07-10 18:35:02 +02:00
drbd_main.c drbd: Only use drbd_msg_put_info() in drbd_nl.c 2014-11-10 09:27:33 -07:00
drbd_nl.c drbd: fix race between role change and handshake 2014-11-10 09:27:35 -07:00
drbd_nla.c drbd: Remove drbd_wrappers.h 2014-04-30 13:46:54 -06:00
drbd_nla.h drbd: Split off netlink mandatory attribute handling into separate file 2012-11-08 16:57:45 +01:00
drbd_proc.c drbd: Add missing newline in resync progress display in /proc/drbd 2014-09-11 08:41:29 -06:00
drbd_protocol.h drbd: Enable QUEUE_FLAG_DISCARD only if the peer can recieve P_TRIM 2014-04-30 13:46:55 -06:00
drbd_receiver.c block: Add discard flag to blkdev_issue_zeroout() function 2015-01-21 10:41:46 -07:00
drbd_req.c drbd: use generic io stats accounting functions to simplify io stat accounting 2014-11-24 08:05:14 -07:00
drbd_req.h drbd: silence -Wmissing-prototypes warnings 2014-07-10 18:34:57 +02:00
drbd_state.c drbd: fix resync throttling initialization 2014-11-10 09:27:37 -07:00
drbd_state.h drbd: fix race between role change and handshake 2014-11-10 09:27:35 -07:00
drbd_strings.c drbd: Move string function prototypes from linux/drbd.h to drbd_string.h 2014-02-17 16:50:37 +01:00
drbd_strings.h drbd: Move string function prototypes from linux/drbd.h to drbd_string.h 2014-02-17 16:50:37 +01:00
drbd_vli.h Fix common misspellings 2011-03-31 11:26:23 -03:00
drbd_worker.c drbd: fix resync throttling initialization 2014-11-10 09:27:37 -07:00