Re: [PATCH 4/7][TAKE5] support new modes in fallocate

Andreas Dilger
2007-06-25T21:52:44Z

On Jun 25, 2007 19:15 +0530, Amit K. Arora wrote:
> +#define FA_FL_DEALLOC 0x01 /* default is allocate */
> +#define FA_FL_KEEP_SIZE 0x02 /* default is extend/shrink size */
> +#define FA_FL_DEL_DATA 0x04 /* default is keep written data on DEALLOC */

In XFS one of the (many) ALLOC modes is to zero existing data on allocate.
For ext4 all this would mean is calling ext4_ext_mark_uninitialized() on
each extent. For some workloads this would be much faster than truncate
and reallocate of all the blocks in a file.

In that light, please change the comment to /* default is keep existing data */
so that it doesn't imply this is only for DEALLOC.

Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.