xfs: remove xfs_probe_cluster

xfs_map_blocks always calls xfs_bmapi with the XFS_BMAPI_ENTIRE
entire flag, which tells it to not cap the extent at the passed in
size, but just treat the size as an minimum to map.  This means
xfs_probe_cluster is entirely useless as we'll always get the whole
extent back anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Alex Elder <aelder@sgi.com>

fs/xfs/linux-2.6/xfs_aops.c

@@ -304,13 +304,13 @@ STATIC int
 xfs_map_blocks(
 	struct inode		*inode,
 	loff_t			offset,
-	ssize_t			count,
 	struct xfs_bmbt_irec	*imap,
 	int			type,
 	int			nonblocking)
 {
 	struct xfs_inode	*ip = XFS_I(inode);
 	struct xfs_mount	*mp = ip->i_mount;
+	ssize_t			count = 1 << inode->i_blkbits;
 	xfs_fileoff_t		offset_fsb, end_fsb;
 	int			error = 0;
 	int			bmapi_flags = XFS_BMAPI_ENTIRE;
@@ -634,108 +634,6 @@ xfs_map_at_offset(
 	clear_buffer_unwritten(bh);
 }
 
-/*
- * Look for a page at index that is suitable for clustering.
- */
-STATIC unsigned int
-xfs_probe_page(
-	struct page		*page,
-	unsigned int		pg_offset)
-{
-	struct buffer_head	*bh, *head;
-	int			ret = 0;
-
-	if (PageWriteback(page))
-		return 0;
-	if (!PageDirty(page))
-		return 0;
-	if (!page->mapping)
-		return 0;
-	if (!page_has_buffers(page))
-		return 0;
-
-	bh = head = page_buffers(page);
-	do {
-		if (!buffer_uptodate(bh))
-			break;
-		if (!buffer_mapped(bh))
-			break;
-		ret += bh->b_size;
-		if (ret >= pg_offset)
-			break;
-	} while ((bh = bh->b_this_page) != head);
-
-	return ret;
-}
-
-STATIC size_t
-xfs_probe_cluster(
-	struct inode		*inode,
-	struct page		*startpage,
-	struct buffer_head	*bh,
-	struct buffer_head	*head)
-{
-	struct pagevec		pvec;
-	pgoff_t			tindex, tlast, tloff;
-	size_t			total = 0;
-	int			done = 0, i;
-
-	/* First sum forwards in this page */
-	do {
-		if (!buffer_uptodate(bh) || !buffer_mapped(bh))
-			return total;
-		total += bh->b_size;
-	} while ((bh = bh->b_this_page) != head);
-
-	/* if we reached the end of the page, sum forwards in following pages */
-	tlast = i_size_read(inode) >> PAGE_CACHE_SHIFT;
-	tindex = startpage->index + 1;
-
-	/* Prune this back to avoid pathological behavior */
-	tloff = min(tlast, startpage->index + 64);
-
-	pagevec_init(&pvec, 0);
-	while (!done && tindex <= tloff) {
-		unsigned len = min_t(pgoff_t, PAGEVEC_SIZE, tlast - tindex + 1);
-
-		if (!pagevec_lookup(&pvec, inode->i_mapping, tindex, len))
-			break;
-
-		for (i = 0; i < pagevec_count(&pvec); i++) {
-			struct page *page = pvec.pages[i];
-			size_t pg_offset, pg_len = 0;
-
-			if (tindex == tlast) {
-				pg_offset =
-				    i_size_read(inode) & (PAGE_CACHE_SIZE - 1);
-				if (!pg_offset) {
-					done = 1;
-					break;
-				}
-			} else
-				pg_offset = PAGE_CACHE_SIZE;
-
-			if (page->index == tindex && trylock_page(page)) {
-				pg_len = xfs_probe_page(page, pg_offset);
-				unlock_page(page);
-			}
-
-			if (!pg_len) {
-				done = 1;
-				break;
-			}
-
-			total += pg_len;
-			tindex++;
-		}
-
-		pagevec_release(&pvec);
-		cond_resched();
-	}
-
-	return total;
-}
-
 /*
  * Test if a given page is suitable for writing as part of an unwritten
  * or delayed allocate extent.
@@ -1028,7 +926,7 @@ xfs_vm_writepage(
 	unsigned int		type;
 	__uint64_t              end_offset;
 	pgoff_t                 end_index, last_index;
-	ssize_t			size, len;
+	ssize_t			len;
 	int			err, imap_valid = 0, uptodate = 1;
 	int			count = 0;
 	int			all_bh = 0;
@@ -1133,7 +1031,7 @@ xfs_vm_writepage(
 				 * for unwritten extent conversion.
 				 */
 				new_ioend = 1;
-				err = xfs_map_blocks(inode, offset, len, &imap,
+				err = xfs_map_blocks(inode, offset, &imap,
 						     type, nonblocking);
 				if (err)
 					goto error;
@@ -1158,8 +1056,7 @@ xfs_vm_writepage(
 			}
 			if (!imap_valid) {
 				new_ioend = 1;
-				size = xfs_probe_cluster(inode, page, bh, head);
+				err = xfs_map_blocks(inode, offset,
-				err = xfs_map_blocks(inode, offset, size,
 						&imap, type, nonblocking);
 				if (err)
 					goto error;