zfs/module
Etienne Dechamps bbdc6ae495 Add interface for file hole punching.
This adds an interface to "punch holes" (deallocate space) in VFS
files. The interface is identical to the Solaris VOP_SPACE interface.
This interface is necessary for TRIM support on file vdevs.

This is implemented using Linux fallocate(FALLOC_FL_PUNCH_HOLE), which
was introduced in 2.6.38. For a brief time before 2.6.38 this was done
using the truncate_range inode operation, which was quickly deprecated.
This patch only supports FALLOC_FL_PUNCH_HOLE.

This adds support for the truncate_range() inode operation to
VOP_SPACE() for file hole punching. This API is deprecated and removed
in 3.5, so it's only useful for old kernels.

On tmpfs, the truncate_range() inode operation translates to
shmem_truncate_range(). Unfortunately, this function expects the end
offset to be inclusive and aligned to the end of a page. If it is not,
the kernel will stop with a BUG_ON().

This patch fixes the issue by adapting to the constraints set forth by
shmem_truncate_range().

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #168
2012-10-04 16:22:07 -07:00
..
spl Add interface for file hole punching. 2012-10-04 16:22:07 -07:00
splat Enhance SPLAT kmem:slab_overcommit test 2012-08-30 15:49:00 -07:00
.gitignore Remove Makefile from non-toplevel .gitignore files 2012-08-23 12:49:04 -07:00
Makefile.in Add script for builtin module building. 2012-07-26 15:13:09 -07:00