Re: [PATCH v5 0/10] fs: Introduce new flag(FALLOC_FL_COLLAPSE_RANGE) for fallocate

Dave Chinner
2014-02-24T00:57:10Z

On Wed, Feb 19, 2014 at 01:37:16AM +0900, Namjae Jeon wrote:
> From: Namjae Jeon <namjae.jeon@samsung.com>
>
> This patch series 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 an fallocate operation
> and not any fs specific ioctl, hence we add this functionality to fallocate.
>
> This patch series introduces new flag FALLOC_FL_COLLAPSE_RANGE for fallocate
> and implements it for XFS and Ext4.
>
> The semantics of this flag are following:
> 1) It collapses the range lying between offset and length by removing any data
> blocks which are present in this range and than updates all the logical
> offsets of extents beyond "offset + len" to nullify the hole created by
> removing blocks. In short, it does not leave a hole.
> 2) It should be used exclusively. No other fallocate flag in combination.
> 3) Offset and length supplied to fallocate should be fs block size aligned
> in case of xfs and ext4.
> 4) Collaspe range does not work beyond i_size.
>
> 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.
>
> Namjae Jeon (10):
> fs: Add new flag(FALLOC_FL_COLLAPSE_RANGE) for fallocate
> xfs: Add support FALLOC_FL_COLLAPSE_RANGE for fallocate

I've pushed these to the following branch:

git://oss.sgi.com/xfs/xfs.git xfs-collapse-range

And so they'll be in tomorrow's linux-next tree.

> ext4: Add support FALLOC_FL_COLLAPSE_RANGE for fallocate

I've left this one alone for the ext4 guys to sort out.

> xfsprog: xfsio: Add support FALLOC_FL_COLLAPSE_RANGE for fallocate

That's already in a current xfstests tree.

> xfstest: shared/001: Standard collapse range tests
> xfstest: shared/002: Delayed allocation collapse range
> xfstest: shared/003: Multi collapse range tests
> xfstest: shared/004: Delayed allocation multi collapse
> xfstest: shared/005: Test multiple fallocate collapse

These are now in the xfstests git tree.

> manpage: update FALLOC_FL_COLLAPSE_RANGE flag in fallocate

And Michael will need to review and commit that to the kernel
manpages tree.

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com

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