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c83f6bf98d
linux/block
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Vivek Goyal c83f6bf98d block: add partition resize function to blkpg ioctl 
Add a new operation code (BLKPG_RESIZE_PARTITION) to the BLKPG ioctl that
allows altering the size of an existing partition, even if it is currently
in use.

This patch converts hd_struct->nr_sects into sequence counter because
One might extend a partition while IO is happening to it and update of
nr_sects can be non-atomic on 32bit machines with 64bit sector_t. This
can lead to issues like reading inconsistent size of a partition. Sequence
counter have been used so that readers don't have to take bdev mutex lock
as we call sector_in_part() very frequently.

Now all the access to hd_struct->nr_sects should happen using sequence
counter read/update helper functions part_nr_sects_read/part_nr_sects_write.
There is one exception though, set_capacity()/get_capacity(). I think
theoritically race should exist there too but this patch does not
modify set_capacity()/get_capacity() due to sheer number of call sites
and I am afraid that change might break something. I have left that as a
TODO item. We can handle it later if need be. This patch does not introduce
any new races as such w.r.t set_capacity()/get_capacity().

v2: Add CONFIG_LBDAF test to UP preempt case as suggested by Phillip.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Phillip Susi <psusi@ubuntu.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-08-01 12:24:18 +02:00
..
partitions s390/dasd: re-prioritize partition detection message 2012-05-16 14:42:51 +02:00
blk-cgroup.c blkcg: implement per-blkg request allocation 2012-06-26 18:42:49 -04:00
blk-cgroup.h blkcg: implement per-blkg request allocation 2012-06-26 18:42:49 -04:00
blk-core.c blkcg: implement per-blkg request allocation 2012-06-26 18:42:49 -04:00
blk-exec.c block: add missing blk_queue_dead() checks 2011-12-14 00:33:37 +01:00
blk-flush.c blk-flush: move the queue kick into 2011-10-24 16:24:31 +02:00
blk-integrity.c block: add export.h to files using EXPORT_SYMBOL/THIS_MODULE macros 2011-10-31 19:31:12 -04:00
blk-ioc.c block: uninitialized ioc->nr_tasks triggers WARN_ON 2012-08-01 12:17:27 +02:00
blk-iopoll.c tree-wide: fix assorted typos all over the place 2009-12-04 15:39:55 +01:00
blk-lib.c block: fix patch import error in max_discard_sectors check 2011-07-23 20:34:59 +02:00
blk-map.c block: re-use existing 'reading' variable instead of checking direction again 2011-12-21 15:27:24 +01:00
blk-merge.c block: separate out blk_rq_merge_ok() and blk_try_merge() from elevator functions 2012-02-08 09:19:38 +01:00
blk-settings.c block: do not artificially constrain max_sectors for stacking drivers 2012-08-01 10:44:28 +02:00
blk-softirq.c sched, block: Unify cache detection 2012-01-27 13:28:48 +01:00
blk-sysfs.c blkcg: implement per-blkg request allocation 2012-06-26 18:42:49 -04:00
blk-tag.c block: fix blk_queue_end_tag() 2011-12-29 09:16:28 +01:00
blk-throttle.c block: allocate io_context upfront 2012-06-25 11:53:50 +02:00
blk-timeout.c block: Drop dead function blk_abort_queue() 2012-06-15 08:46:23 +02:00
blk.h block: prepare for multiple request_lists 2012-06-25 11:53:52 +02:00
bsg-lib.c block: drop custom queue draining used by scsi_transport_{iscsi|fc} 2012-06-25 11:53:48 +02:00
bsg.c bsg: fix sysfs link remove warning 2012-02-08 20:02:03 +01:00
cfq-iosched.c block: blkcg_policy_cfq shouldn't be used if !CONFIG_CFQ_GROUP_IOSCHED 2012-06-04 10:02:29 +02:00
compat_ioctl.c block: Add BLKROTATIONAL ioctl 2012-01-11 16:29:31 +01:00
deadline-iosched.c elevator: make elevator_init_fn() return 0/-errno 2012-03-06 21:27:21 +01:00
elevator.c blkcg: implement per-queue policy activation 2012-04-20 10:06:06 +02:00
genhd.c block: add partition resize function to blkpg ioctl 2012-08-01 12:24:18 +02:00
ioctl.c block: add partition resize function to blkpg ioctl 2012-08-01 12:24:18 +02:00
Kconfig move fs/partitions to block/ 2012-01-03 22:54:06 -05:00
Kconfig.iosched blkcg: make CONFIG_BLK_CGROUP bool 2012-03-06 21:27:21 +01:00
Makefile separate partition format handling from generic code 2012-01-03 22:54:06 -05:00
noop-iosched.c elevator: make elevator_init_fn() return 0/-errno 2012-03-06 21:27:21 +01:00
partition-generic.c block: add partition resize function to blkpg ioctl 2012-08-01 12:24:18 +02:00
scsi_ioctl.c scsi: Silence unnecessary warnings about ioctl to partition 2012-06-15 12:52:46 +02:00