tree 9c315d879a8b18f6245d357090b19bd433ef5f57
parent 38dbfb59d1175ef458d006556061adeaa8751b72
author Namjae Jeon <namjae.jeon@samsung.com> 1393199895 +1100
committer Dave Chinner <david@fromorbit.com> 1393199895 +1100

fs: Add new flag(FALLOC_FL_COLLAPSE_RANGE) for fallocate

This patch is in response of the following post:
http://lwn.net/Articles/556136/
"ext4: introduce two new ioctls"

Dave chinner suggested that truncate_block_range
(which was one of the ioctls name) should be a fallocate operation
and not any fs specific ioctl, hence we add this functionality to new flags of fallocate.

This new functionality of collapsing range could be used by media editing tools
which does non linear editing to quickly purge and edit parts of a media file.
This will immensely improve the performance of these operations.
The limitation of fs block size aligned offsets can be easily handled
by media codecs which are encapsulated in a conatiner as they have to
just change the offset to next keyframe value to match the proper alignment.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Ashish Sangwan <a.sangwan@samsung.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>