On Wed, Jun 29, 2011 at 10:01:18AM -0400, Christoph Hellwig wrote:

Split the guts of xfs_itruncate_finish that loop over the existing extents
and calls xfs_bunmapi on them into a new helper, xfs_itruncate_externs.
Make xfs_attr_inactive call it directly instead of xfs_itruncate_finish,
which allows to simplify the latter a lot, by only letting it deal with
the data fork.  As a result xfs_itruncate_finish is renamed to
xfs_itruncate_data to make its use case more obvious.

Also remove the sync parameter from xfs_itruncate_data, which has been
unessecary since the introduction of the busy extent list in 2002, and
completely dead code since 2003 when the XFS_BMAPI_ASYNC parameter was
made a no-op.

I can't actually see why the xfs_attr_inactive needs to set the transaction
sync, but let's keep this patch simple and without changes in behaviour.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Overall, looks good. A few minor comments in line, but consider it

Reviewed-by: Dave Chinner <redacted>

+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_trans	*ntp = *tpp;
+	xfs_bmap_free_t		free_list;
+	xfs_fsblock_t		first_block;
+	xfs_fileoff_t		first_unmap_block;
+	xfs_fileoff_t		last_block;
+	xfs_filblks_t		unmap_len;
+	int			committed;
+	int			error = 0;
+	int			done = 0;
 
 	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_IOLOCK_EXCL));
-	ASSERT((new_size == 0) || (new_size <= ip->i_size));
-	ASSERT(*tp != NULL);
-	ASSERT((*tp)->t_flags & XFS_TRANS_PERM_LOG_RES);
-	ASSERT(ip->i_transp == *tp);
+	ASSERT(new_size == 0 || new_size <= ip->i_size);

If new_size == 0, then it will always be <= ip->i_size, so that's
kind of a redundant check. I think this really should be two
different asserts, one that validates the data fork new_size range,
and one that validates the attr fork truncate to zero length only
condition:

	ASSERT(new_size <= ip->i_size);
	ASSERT(whichfork != XFS_ATTR_FORK || new_size == 0);

I've always found this a mess to follow which transaction is which
because of the rewriting of ntp. This is easier to follow:

		ntp = xfs_trans_dup(*tpp);
		error = xfs_trans_commit(*tpp, 0);
		*tpp = ntp;

Now it's clear that we are duplicating *tpp, then committing it, and
then setting it to the duplicated transaction. Now I don't have to
go look at all the surrounding code to remind myself what ntp
contains to validate that the fragment of code is doing the right
thing.....

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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