xfs: remove xfs_page_mkwrite_iomap_ops

Shared the regular buffered write iomap_ops with the page fault path
and just check for the IOMAP_FAULT flag to skip delalloc punching.

This keeps the delalloc punching checks in one place, and will make it
easier to convert iomap to an iter model where the begin and end
handlers are merged into a single callback.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

Author: Christoph Hellwig

fs/xfs/xfs_file.c

@@ -1474,7 +1474,7 @@ xfs_write_fault(
 	if (IS_DAX(inode))
 		ret = xfs_dax_fault_locked(vmf, order, true);
 	else
-		ret = iomap_page_mkwrite(vmf, &xfs_page_mkwrite_iomap_ops);
+		ret = iomap_page_mkwrite(vmf, &xfs_buffered_write_iomap_ops);
 	xfs_iunlock(ip, lock_mode);
 
 	sb_end_pagefault(inode->i_sb);

fs/xfs/xfs_iomap.c

@@ -1234,6 +1234,14 @@ xfs_buffered_write_iomap_end(
 	if (iomap->type != IOMAP_DELALLOC || !(iomap->flags & IOMAP_F_NEW))
 		return 0;
 
+	/*
+	 * iomap_page_mkwrite() will never fail in a way that requires delalloc
+	 * extents that it allocated to be revoked.  Hence never try to release
+	 * them here.
+	 */
+	if (flags & IOMAP_FAULT)
+		return 0;
+
 	/* Nothing to do if we've written the entire delalloc extent */
 	start_byte = iomap_last_written_block(inode, offset, written);
 	end_byte = round_up(offset + length, i_blocksize(inode));
@@ -1260,15 +1268,6 @@ const struct iomap_ops xfs_buffered_write_iomap_ops = {
 	.iomap_end		= xfs_buffered_write_iomap_end,
 };
 
-/*
- * iomap_page_mkwrite() will never fail in a way that requires delalloc extents
- * that it allocated to be revoked. Hence we do not need an .iomap_end method
- * for this operation.
- */
-const struct iomap_ops xfs_page_mkwrite_iomap_ops = {
-	.iomap_begin		= xfs_buffered_write_iomap_begin,
-};
-
 static int
 xfs_read_iomap_begin(
 	struct inode		*inode,

fs/xfs/xfs_iomap.h

@@ -48,7 +48,6 @@ xfs_aligned_fsb_count(
 }
 
 extern const struct iomap_ops xfs_buffered_write_iomap_ops;
-extern const struct iomap_ops xfs_page_mkwrite_iomap_ops;
 extern const struct iomap_ops xfs_direct_write_iomap_ops;
 extern const struct iomap_ops xfs_read_iomap_ops;
 extern const struct iomap_ops xfs_seek_iomap_ops;