Re: [PATCH 4/5] xfs: simplify the fallocate path

Dave Chinner
2013-10-14T05:05:31Z

On Sat, Oct 12, 2013 at 12:55:07AM -0700, Christoph Hellwig wrote:
> Call xfs_alloc_file_space or xfs_free_file_space directly from
> xfs_file_fallocate instead of going through xfs_change_file_space.
>
> This simplified the code by removing the unessecary marshalling of the
> arguments into an xfs_flock64_t structure and allows removing checks that
> are already done in the VFS code.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
>
> ---
> fs/xfs/xfs_bmap_util.c | 39 ++-----------------------
> fs/xfs/xfs_bmap_util.h | 4 ++
> fs/xfs/xfs_file.c | 76 ++++++++++++++++++++++++++++++-------------------
> 3 files changed, 56 insertions(+), 63 deletions(-)
>
> Index: xfs/fs/xfs/xfs_file.c
> ===================================================================
> --- xfs.orig/fs/xfs/xfs_file.c 2013-10-01 21:06:23.000000000 +0200
> +++ xfs/fs/xfs/xfs_file.c 2013-10-01 21:12:47.552218689 +0200
> @@ -805,44 +805,64 @@ out:
>
> STATIC long
> xfs_file_fallocate(
.....
> + tp = xfs_trans_alloc(ip->i_mount, XFS_TRANS_WRITEID);
> + error = xfs_trans_reserve(tp, &M_RES(ip->i_mount)->tr_writeid, 0, 0);
> + if (error) {
> + xfs_trans_cancel(tp, 0);
> + goto out_unlock;
> + }
> +
> + xfs_ilock(ip, XFS_ILOCK_EXCL);
> + xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
> + ip->i_d.di_mode &= ~S_ISUID;
> + if (ip->i_d.di_mode & S_IXGRP)
> + ip->i_d.di_mode &= ~S_ISGID;
> +
> + if (!(mode & FALLOC_FL_PUNCH_HOLE))
> + ip->i_d.di_flags |= XFS_DIFLAG_PREALLOC;
>
> - error = -xfs_change_file_space(ip, cmd, &bf, 0, attr_flags);
> + xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
> + xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
> +
> + if (file->f_flags & O_DSYNC)
> + xfs_trans_set_sync(tp);
> + error = xfs_trans_commit(tp, 0);
> if (error)
> goto out_unlock;

Seems a bit clunky to do all this work when we've got to repeat most
of it when when we call xfs_setattr_size() if the size has changed.
Any thoughts on how we might reduce to a single transaction?

Otherwise it looks ok.

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com