Re: [PATCH 1/6] fs: add hole punching to fallocate

Jan Kara
2010-11-18T23:42:00Z

On Wed 17-11-10 20:46:15, Josef Bacik wrote:
> Hole punching has already been implemented by XFS and OCFS2, and has the
> potential to be implemented on both BTRFS and EXT4 so we need a generic way to
> get to this feature. The simplest way in my mind is to add FALLOC_FL_PUNCH_HOLE
> to fallocate() since it already looks like the normal fallocate() operation.
> I've tested this patch with XFS and BTRFS to make sure XFS did what it's
> supposed to do and that BTRFS failed like it was supposed to. Thank you,
Looks nice now. Acked-by: Jan Kara <jack@suse.cz>

Honza
>
> Signed-off-by: Josef Bacik <josef@redhat.com>
> ---
> fs/open.c | 7 ++++++-
> include/linux/falloc.h | 1 +
> 2 files changed, 7 insertions(+), 1 deletions(-)
>
> diff --git a/fs/open.c b/fs/open.c
> index 4197b9e..5b6ef7e 100644
> --- a/fs/open.c
> +++ b/fs/open.c
> @@ -223,7 +223,12 @@ int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
> return -EINVAL;
>
> /* Return error if mode is not supported */
> - if (mode && !(mode & FALLOC_FL_KEEP_SIZE))
> + if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
> + return -EOPNOTSUPP;
> +
> + /* Punch hole must have keep size set */
> + if ((mode & FALLOC_FL_PUNCH_HOLE) &&
> + !(mode & FALLOC_FL_KEEP_SIZE))
> return -EOPNOTSUPP;
>
> if (!(file->f_mode & FMODE_WRITE))
> diff --git a/include/linux/falloc.h b/include/linux/falloc.h
> index 3c15510..73e0b62 100644
> --- a/include/linux/falloc.h
> +++ b/include/linux/falloc.h
> @@ -2,6 +2,7 @@
> #define _FALLOC_H_
>
> #define FALLOC_FL_KEEP_SIZE 0x01 /* default is extend size */
> +#define FALLOC_FL_PUNCH_HOLE 0x02 /* de-allocates range */
>
> #ifdef __KERNEL__
>
> --
> 1.6.6.1
>
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR