linux/include
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
..
acpi ACPI: Add _PLD support 2012-05-11 17:03:12 -07:00
asm-generic Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-06-01 10:34:35 -07:00
crypto
drm introduce SIZE_MAX 2012-05-31 17:49:26 -07:00
keys
linux block: add partition resize function to blkpg ioctl 2012-08-01 12:24:18 +02:00
math-emu
media [media] patch for Asus My Cinema PS3-100 (1043:48cd) 2012-05-20 16:05:02 -03:00
memory
misc
mtd UBI: amend commentaries WRT dtype 2012-05-20 20:25:59 +03:00
net cipso: handle CIPSO options correctly when NetLabel is disabled 2012-06-01 14:18:29 -04:00
pcmcia
rdma Merge branches 'core', 'cxgb4', 'ipath', 'iser', 'lockdep', 'mlx4', 'nes', 'ocrdma', 'qib' and 'raw-qp' into for-linus 2012-05-21 09:00:47 -07:00
rxrpc
scsi [SCSI] fcoe, bnx2fc, libfcoe: SW FCoE and bnx2fc use FCoE Syfs 2012-05-23 09:43:13 +01:00
sound ASoC: Last minute updates 2012-05-22 02:58:55 +02:00
target target: Add MI_REPORT_TARGET_PGS ext. header + implict_trans_secs attribute 2012-05-17 00:45:58 -07:00
trace mm: vmscan: remove reclaim_mode_t 2012-05-29 16:22:19 -07:00
video fbdev updates for 3.5 2012-06-01 16:57:51 -07:00
xen xen: do not map the same GSI twice in PVHVM guests. 2012-05-21 14:11:36 -04:00
Kbuild