xfs: introduce the xfs_iext_cursor abstraction

Add a new xfs_iext_cursor structure to hide the direct extent map
index manipulations. In addition to the existing lookup/get/insert/
remove and update routines new primitives to get the first and last
extent cursor, as well as moving up and down by one extent are
provided.  Also new are convenience to increment/decrement the
cursor and retreive the new extent, as well as to peek into the
previous/next extent without updating the cursor and last but not
least a macro to iterate over all extents in a fork.

[darrick: rename for_each_iext to for_each_xfs_iext]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

2 files changed, 10 insertions, 10 deletions

diff --git a/fs/xfs/scrub/bmap.c b/fs/xfs/scrub/bmap.c
index 3c17b182616f..be0bc11b6594 100644
--- a/fs/xfs/scrub/bmap.c
+++ b/fs/xfs/scrub/bmap.c
@@ -237,7 +237,7 @@ xfs_scrub_bmap(
 	struct xfs_inode		*ip = sc->ip;
 	struct xfs_ifork		*ifp;
 	xfs_fileoff_t			endoff;
-	xfs_extnum_t			idx;
+	struct xfs_iext_cursor		icur;
 	bool				found;
 	int				error = 0;
 
@@ -317,9 +317,9 @@ xfs_scrub_bmap(
 	/* Scrub extent records. */
 	info.lastoff = 0;
 	ifp = XFS_IFORK_PTR(ip, whichfork);
-	for (found = xfs_iext_lookup_extent(ip, ifp, 0, &idx, &irec);
+	for (found = xfs_iext_lookup_extent(ip, ifp, 0, &icur, &irec);
 	     found != 0;
-	     found = xfs_iext_get_extent(ifp, ++idx, &irec)) {
+	     found = xfs_iext_next_extent(ifp, &icur, &irec)) {
 		if (xfs_scrub_should_terminate(sc, &error))
 			break;
 		if (isnullstartblock(irec.br_startblock))
diff --git a/fs/xfs/scrub/dir.c b/fs/xfs/scrub/dir.c
index c61362faed4a..73ac795aa6a5 100644
--- a/fs/xfs/scrub/dir.c
+++ b/fs/xfs/scrub/dir.c
@@ -614,7 +614,7 @@ xfs_scrub_directory_blocks(
 	xfs_fileoff_t			leaf_lblk;
 	xfs_fileoff_t			free_lblk;
 	xfs_fileoff_t			lblk;
-	xfs_extnum_t			idx;
+	struct xfs_iext_cursor		icur;
 	xfs_dablk_t			dabno;
 	bool				found;
 	int				is_block = 0;
@@ -639,7 +639,7 @@ xfs_scrub_directory_blocks(
 		goto out;
 
 	/* Iterate all the data extents in the directory... */
-	found = xfs_iext_lookup_extent(sc->ip, ifp, lblk, &idx, &got);
+	found = xfs_iext_lookup_extent(sc->ip, ifp, lblk, &icur, &got);
 	while (found) {
 		/* Block directories only have a single block at offset 0. */
 		if (is_block &&
@@ -676,17 +676,17 @@ xfs_scrub_directory_blocks(
 		}
 		dabno = got.br_startoff + got.br_blockcount;
 		lblk = roundup(dabno, args.geo->fsbcount);
-		found = xfs_iext_lookup_extent(sc->ip, ifp, lblk, &idx, &got);
+		found = xfs_iext_lookup_extent(sc->ip, ifp, lblk, &icur, &got);
 	}
 
 	if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
 		goto out;
 
 	/* Look for a leaf1 block, which has free info. */
-	if (xfs_iext_lookup_extent(sc->ip, ifp, leaf_lblk, &idx, &got) &&
+	if (xfs_iext_lookup_extent(sc->ip, ifp, leaf_lblk, &icur, &got) &&
 	    got.br_startoff == leaf_lblk &&
 	    got.br_blockcount == args.geo->fsbcount &&
-	    !xfs_iext_get_extent(ifp, ++idx, &got)) {
+	    !xfs_iext_next_extent(ifp, &icur, &got)) {
 		if (is_block) {
 			xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
 			goto out;
@@ -702,7 +702,7 @@ xfs_scrub_directory_blocks(
 
 	/* Scan for free blocks */
 	lblk = free_lblk;
-	found = xfs_iext_lookup_extent(sc->ip, ifp, lblk, &idx, &got);
+	found = xfs_iext_lookup_extent(sc->ip, ifp, lblk, &icur, &got);
 	while (found) {
 		/*
 		 * Dirs can't have blocks mapped above 2^32.
@@ -740,7 +740,7 @@ xfs_scrub_directory_blocks(
 		}
 		dabno = got.br_startoff + got.br_blockcount;
 		lblk = roundup(dabno, args.geo->fsbcount);
-		found = xfs_iext_lookup_extent(sc->ip, ifp, lblk, &idx, &got);
+		found = xfs_iext_lookup_extent(sc->ip, ifp, lblk, &icur, &got);
 	}
 out:
 	return error;