diff mbox

[13/18] xfs: iterate backwards in xfs_reflink_cancel_cow_blocks

Message ID 20171031142230.11755-14-hch@lst.de (mailing list archive)
State Accepted
Headers show

Commit Message

Christoph Hellwig Oct. 31, 2017, 2:22 p.m. UTC
This follow the iteration oder for extent deletion in both the regular
reflink I/O completion path and normal block truncation, and makes
implementing the new incore extent list easier.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_reflink.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

Comments

Darrick J. Wong Oct. 31, 2017, 10:10 p.m. UTC | #1
On Tue, Oct 31, 2017 at 04:22:25PM +0200, Christoph Hellwig wrote:
> This follow the iteration oder for extent deletion in both the regular
                            ^^^^
Jeez man I didn't think the code smelled /that/ bad. :P

"order", I'm assuming. :)

> reflink I/O completion path and normal block truncation, and makes
> implementing the new incore extent list easier.

"Make consistent the extent iteration order for deleting extents in both
the regular reflink IO completion path and regular block truncation, so
that implementing the new incore extent map is easier." ?

(Eh, the language is still a bit tortured...)

--D

> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/xfs/xfs_reflink.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
> index cadf0ff68003..43bec0def51d 100644
> --- a/fs/xfs/xfs_reflink.c
> +++ b/fs/xfs/xfs_reflink.c
> @@ -569,12 +569,20 @@ xfs_reflink_cancel_cow_blocks(
>  
>  	if (!xfs_is_reflink_inode(ip))
>  		return 0;
> -	if (!xfs_iext_lookup_extent(ip, ifp, offset_fsb, &ext, &got))
> +	if (!xfs_iext_lookup_extent_before(ip, ifp, &end_fsb, &ext, &got))
>  		return 0;
>  
> -	while (got.br_startoff < end_fsb) {
> +	/* Walk backwards until we're out of the I/O range... */
> +	while (got.br_startoff + got.br_blockcount > offset_fsb) {
>  		del = got;
>  		xfs_trim_extent(&del, offset_fsb, end_fsb - offset_fsb);
> +
> +		/* Extent delete may have bumped ext forward */
> +		if (!del.br_blockcount) {
> +			xfs_iext_prev(ifp, &ext);
> +			goto next_extent;
> +		}
> +
>  		trace_xfs_reflink_cancel_cow(ip, &del);
>  
>  		if (isnullstartblock(del.br_startblock)) {
> @@ -612,8 +620,8 @@ xfs_reflink_cancel_cow_blocks(
>  			/* Remove the mapping from the CoW fork. */
>  			xfs_bmap_del_extent_cow(ip, &ext, &got, &del);
>  		}
> -
> -		if (!xfs_iext_next_extent(ifp, &ext, &got))
> +next_extent:
> +		if (!xfs_iext_get_extent(ifp, &ext, &got))
>  			break;
>  	}
>  
> -- 
> 2.14.2
> 
> --
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diff mbox

Patch

diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index cadf0ff68003..43bec0def51d 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -569,12 +569,20 @@  xfs_reflink_cancel_cow_blocks(
 
 	if (!xfs_is_reflink_inode(ip))
 		return 0;
-	if (!xfs_iext_lookup_extent(ip, ifp, offset_fsb, &ext, &got))
+	if (!xfs_iext_lookup_extent_before(ip, ifp, &end_fsb, &ext, &got))
 		return 0;
 
-	while (got.br_startoff < end_fsb) {
+	/* Walk backwards until we're out of the I/O range... */
+	while (got.br_startoff + got.br_blockcount > offset_fsb) {
 		del = got;
 		xfs_trim_extent(&del, offset_fsb, end_fsb - offset_fsb);
+
+		/* Extent delete may have bumped ext forward */
+		if (!del.br_blockcount) {
+			xfs_iext_prev(ifp, &ext);
+			goto next_extent;
+		}
+
 		trace_xfs_reflink_cancel_cow(ip, &del);
 
 		if (isnullstartblock(del.br_startblock)) {
@@ -612,8 +620,8 @@  xfs_reflink_cancel_cow_blocks(
 			/* Remove the mapping from the CoW fork. */
 			xfs_bmap_del_extent_cow(ip, &ext, &got, &del);
 		}
-
-		if (!xfs_iext_next_extent(ifp, &ext, &got))
+next_extent:
+		if (!xfs_iext_get_extent(ifp, &ext, &got))
 			break;
 	}