[Drbd-dev] [PATCHSET] block: clean up bdev claim/release handling
neilb at suse.de
Mon Nov 1 20:49:18 CET 2010
On Mon, 1 Nov 2010 17:15:24 +0100
Tejun Heo <tj at kernel.org> wrote:
> bdev exclusive access handling is somewhat clumsy. The primary
> interface is bd_claim() and bd_release() but there also are
> open_bdev_exclusive(), close_bdev_exclusive() and bd_claim_by_disk()
> and bd_release_from_disk().
> Gaining exclusive access as a separate step from open itself also has
> the inherent problem that the block layer doesn't know whether the
> current open attempt is for an exclusive access or not. The action of
> open itself may affect the existing exclusive access but there's no
> way to prevent it.
> This patchset simplifies the claim/release handling by folding it into
> blkdev_get/put() and making others simple wrappers around them. This
> simplifies code and removes strange corner cases like the
> non-atomicity of exclusive open described above.
This looks like a really nice clean-up! Thanks.
Acked-by: NeilBrown <neilb at suse.de>
for the md parts.
> There are five patches in this series.
> 0001-0002 are fixes regarding exclusive bdev opens. 0003 simplifies
> holder/slave symlink handling. 0004 folds bdev claim/release into
> blkdev_get/put(). 0005 reorganizes implementation a bit.
> Cleaning up claim/release handling enables implementation of in-kernel
> disk event polling which be posted soon. Although this patchset
> touches various files including drivers and filesystems, the changes
> there are mostly trivial and I think it would be best to route these
> through the block tree.
> This patchset is on top of 2.6.37-rc1 and available in the following
> git tree.
> This patchset reduces about 400 lines of code.
> block/ioctl.c | 5
> drivers/block/drbd/drbd_int.h | 2
> drivers/block/drbd/drbd_main.c | 7
> drivers/block/drbd/drbd_nl.c | 103 ++-----
> drivers/block/pktcdvd.c | 22 -
> drivers/char/raw.c | 14
> drivers/md/dm-table.c | 20 -
> drivers/md/md.c | 16 -
> drivers/mtd/devices/block2mtd.c | 10
> drivers/s390/block/dasd_genhd.c | 2
> fs/block_dev.c | 576
> fs/btrfs/volumes.c | 14
> fs/ext3/super.c | 12
> fs/ext4/super.c | 12
> fs/gfs2/ops_fstype.c | 4
> fs/jfs/jfs_logmgr.c | 17 -
> fs/logfs/dev_bdev.c | 4
> fs/nilfs2/super.c | 4
> fs/ocfs2/cluster/heartbeat.c | 2
> fs/partitions/check.c | 2
> fs/reiserfs/journal.c | 17 -
> fs/super.c | 14
> fs/xfs/linux-2.6/xfs_super.c | 2
> include/linux/fs.h | 22 -
> kernel/power/swap.c | 5
> mm/swapfile.c | 7 26 files changed, 260
> insertions(+), 655 deletions(-)
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