mirror_zfs/module
Brian Behlendorf e26ade5101 Fix zvol+btrfs hang
When using a zvol to back a btrfs filesystem the btrfs mount
would hang.  This was due to the bio completion callback used
in btrfs assuming that lower level drivers would never modify
the bio->bi_io_vecs after they were submitted via bio_submit().
If they are modified btrfs will miscalculate which pages need
to be unlocked resulting in a hang.

It's worth mentioning that other file systems such as ext[234]
and xfs work fine because they do not make the same assumption
in the bio completion callback.

The most straight forward way to fix the issue is to present
the semantics expected by btrfs.  This is done by cloning the
bios attached to each request and then using the clones bvecs
to perform the required accounting.  The clones are freed after
each read/write and the original unmodified bios are linked back
in to the request.

Signed-off-by: Chris Wedgwood <cw@f00f.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #469
2012-11-09 12:24:51 -08:00
..
avl Add script for builtin module building. 2012-07-26 13:45:09 -07:00
nvpair Add script for builtin module building. 2012-07-26 13:45:09 -07:00
unicode Add script for builtin module building. 2012-07-26 13:45:09 -07:00
zcommon Illumos #1948: zpool list should show more detailed pool info 2012-09-19 13:39:05 -07:00
zfs Fix zvol+btrfs hang 2012-11-09 12:24:51 -08:00
zpios Add script for builtin module building. 2012-07-26 13:45:09 -07:00
.gitignore Add .gitignore files to exclude build products 2010-01-08 11:35:17 -08:00
Makefile.in Add script for builtin module building. 2012-07-26 13:45:09 -07:00