xfs: use iomap for blocksize == PAGE_SIZE readpage and readpages

For file systems with a block size that equals the page size we never do
partial reads, so we can use the buffer_head-less iomap versions of
readpage and readpages without conflicting with the buffer_head structures
create later in write_begin.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 8eb3ba3d4d00..85e1a625d42a 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -1401,6 +1401,8 @@ xfs_vm_readpage(
 	struct page		*page)
 {
 	trace_xfs_vm_readpage(page->mapping->host, 1);
+	if (i_blocksize(page->mapping->host) == PAGE_SIZE)
+		return iomap_readpage(page, &xfs_iomap_ops);
 	return mpage_readpage(page, xfs_get_blocks);
 }
 
@@ -1412,6 +1414,8 @@ xfs_vm_readpages(
 	unsigned		nr_pages)
 {
 	trace_xfs_vm_readpages(mapping->host, nr_pages);
+	if (i_blocksize(mapping->host) == PAGE_SIZE)
+		return iomap_readpages(mapping, pages, nr_pages, &xfs_iomap_ops);
 	return mpage_readpages(mapping, pages, nr_pages, xfs_get_blocks);
 }