Adrian Hunter f281fb5fe5 block: prevent merges of discard and write requests ...

Add logic to prevent two I/O requests being merged if
only one of them is a discard.  Ditto secure discard.

Without this fix, it is possible for write requests
to transform into discard requests.  For example:

  Submit bio 1 to discard 8 sectors from sector n
  Submit bio 2 to write 8 sectors from sector n + 16
  Submit bio 3 to write 8 sectors from sector n + 8

Bio 1 becomes request 1.  Bio 2 becomes request 2.
Bio 3 is merged with request 2, and then subsequently
request 2 is merged with request 1 resulting in just
one I/O request which discards all 24 sectors.

Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>

(Moved the checks above the position checks /Jens)

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

2010-09-25 12:42:55 +02:00

..

blk-barrier.c

block: set up rq->rq_disk properly for flush requests

2010-08-07 18:52:41 +02:00

blk-cgroup.c

blkio: Fix return code for mkdir calls

2010-08-23 10:56:30 +02:00

blk-cgroup.h

blk-cgroup: config options re-arrangement

2010-04-26 19:27:56 +02:00

blk-core.c

BLOCK: fix bio.bi_rw handling

2010-08-23 12:33:10 +02:00

blk-exec.c

block: remove wrappers for request type/flags

2010-08-07 18:17:56 +02:00

blk-integrity.c

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

2010-03-30 22:02:32 +09:00

blk-ioc.c

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

2010-03-30 22:02:32 +09:00

blk-iopoll.c

tree-wide: fix assorted typos all over the place

2009-12-04 15:39:55 +01:00

blk-lib.c

block: add secure discard

2010-08-12 08:43:30 -07:00

blk-map.c

block: fix blk_rq_map_kern bio direction flag

2010-09-21 11:49:17 +02:00

blk-merge.c

block: prevent merges of discard and write requests

2010-09-25 12:42:55 +02:00

blk-settings.c

block: implement an unprep function corresponding directly to prep

2010-08-07 18:23:47 +02:00

blk-softirq.c

generic-ipi: remove CSD_FLAG_WAIT

2009-02-25 14:13:44 +01:00

blk-sysfs.c

block: put dev->kobj in blk_register_queue fail path

2010-08-23 12:30:29 +02:00

blk-tag.c

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

2010-03-30 22:02:32 +09:00

blk-timeout.c

block: ensure jiffies wrap is handled correctly in blk_rq_timed_out_timer

2010-04-21 17:42:08 +02:00

blk.h

block: Range check cpu in blk_cpu_to_group

2010-09-10 09:03:21 +02:00

bsg.c

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

2010-03-30 22:02:32 +09:00

cfq-iosched.c

cfq-iosched: fix a kernel OOPs when usb key is inserted

2010-09-21 11:49:17 +02:00

cfq.h

cfq: fix recursive call in cfq_blkiocg_update_completion_stats()

2010-06-21 09:10:55 +02:00

compat_ioctl.c

block: add secure discard

2010-08-12 08:43:30 -07:00

deadline-iosched.c

block: convert to pos and nr_sectors accessors

2009-05-11 09:50:54 +02:00

elevator.c

block: add function call to switch the IO scheduler from a driver

2010-08-23 13:52:19 +02:00

genhd.c

block: remove all rcu head initializations

2010-05-21 20:01:02 +02:00

ioctl.c

block: add secure discard

2010-08-12 08:43:30 -07:00

Kconfig

blk-cgroup: config options re-arrangement

2010-04-26 19:27:56 +02:00

Kconfig.iosched

blk-cgroup: config options re-arrangement

2010-04-26 19:27:56 +02:00

Makefile

blkdev: move blkdev_issue helper functions to separate file

2010-04-28 19:47:36 +02:00

noop-iosched.c

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

2010-03-30 22:02:32 +09:00

scsi_ioctl.c

block/scsi_ioctl.c: quiet sparse noise

2009-11-04 09:10:33 +01:00