[PATCH 05/15] xfs: Support large pages

[Matthew Wilcox]

From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>

Mostly this is just checking the page size of each page instead of
assuming PAGE_SIZE.  Clean up the logic in writepage a little.

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
 fs/xfs/xfs_aops.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 102cfd8a97d6..1a26e9ca626b 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -765,7 +765,7 @@ xfs_add_to_ioend(
 	struct xfs_mount	*mp = ip->i_mount;
 	struct block_device	*bdev = xfs_find_bdev_for_inode(inode);
 	unsigned		len = i_blocksize(inode);
-	unsigned		poff = offset & (PAGE_SIZE - 1);
+	unsigned		poff = offset & (page_size(page) - 1);
 	bool			merged, same_page = false;
 	sector_t		sector;
 
@@ -843,7 +843,7 @@ xfs_aops_discard_page(
 	if (error && !XFS_FORCED_SHUTDOWN(mp))
 		xfs_alert(mp, "page discard unable to remove delalloc mapping.");
 out_invalidate:
-	xfs_vm_invalidatepage(page, 0, PAGE_SIZE);
+	xfs_vm_invalidatepage(page, 0, page_size(page));
 }
 
 /*
@@ -984,8 +984,7 @@ xfs_do_writepage(
 	struct xfs_writepage_ctx *wpc = data;
 	struct inode		*inode = page->mapping->host;
 	loff_t			offset;
-	uint64_t              end_offset;
-	pgoff_t                 end_index;
+	uint64_t		end_offset;
 
 	trace_xfs_writepage(inode, page, 0, 0);
 
@@ -1024,10 +1023,9 @@ xfs_do_writepage(
 	 * ---------------------------------^------------------|
 	 */
 	offset = i_size_read(inode);
-	end_index = offset >> PAGE_SHIFT;
-	if (page->index < end_index)
-		end_offset = (xfs_off_t)(page->index + 1) << PAGE_SHIFT;
-	else {
+	end_offset = file_offset_of_next_page(page);
+
+	if (end_offset > offset) {
 		/*
 		 * Check whether the page to write out is beyond or straddles
 		 * i_size or not.
@@ -1039,7 +1037,8 @@ xfs_do_writepage(
 		 * |				    |      Straddles     |
 		 * ---------------------------------^-----------|--------|
 		 */
-		unsigned offset_into_page = offset & (PAGE_SIZE - 1);
+		unsigned offset_into_page = offset_in_this_page(page, offset);
+		pgoff_t end_index = offset >> PAGE_SHIFT;
 
 		/*
 		 * Skip the page if it is fully outside i_size, e.g. due to a
@@ -1070,7 +1069,7 @@ xfs_do_writepage(
 		 * memory is zeroed when mapped, and writes to that region are
 		 * not written out to the file."
 		 */
-		zero_user_segment(page, offset_into_page, PAGE_SIZE);
+		zero_user_segment(page, offset_into_page, page_size(page));
 
 		/* Adjust the end_offset to the end of file */
 		end_offset = offset;
-- 
2.23.0