[PATCH RFC 2/8] xfs: introduce extents to local conversion helper

[Shan Hai <shan.hai@oracle.com>]

Delete the extents from xfs inode, copy the data into the data fork,
convert the inode from extents to local format and specify log the
core and data fork of the inode.

Signed-off-by: Shan Hai <shan.hai@oracle.com>
---
 fs/xfs/libxfs/xfs_bmap.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++-
 fs/xfs/libxfs/xfs_bmap.h |  4 ++++
 2 files changed, 63 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 7205268b30bc..bea6dc254a7d 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2000-2006 Silicon Graphics, Inc.
+ * Copyright (c) 2018 Oracle.
  * All Rights Reserved.
  */
 #include "xfs.h"
@@ -213,7 +214,7 @@ xfs_default_attroffset(
  * attribute fork from local to extent format - we reset it where
  * possible to make space available for inline data fork extents.
  */
-STATIC void
+void
 xfs_bmap_forkoff_reset(
 	xfs_inode_t	*ip,
 	int		whichfork)
@@ -5141,6 +5142,63 @@ xfs_bmap_del_extent_real(
 }
 
 /*
+ * Convert an inode from extents to the local format.
+ * Free all the extents of the inode and reset it to the local
+ * format. Copy the contents of the inode's blocks to the inode's
+ * literal area.
+ */
+int
+xfs_bmap_extents_to_local(
+	xfs_trans_t		*tp,
+	xfs_inode_t		*ip,
+	struct xfs_defer_ops	*dfops,
+	int			*logflagsp,
+	int			whichfork,
+	struct page		*page)
+{
+	xfs_ifork_t		*ifp = XFS_IFORK_PTR(ip, whichfork);
+	xfs_fileoff_t		isize = i_size_read(VFS_I(ip));
+	struct xfs_bmbt_irec	got, del;
+	struct xfs_iext_cursor	icur;
+	int			error = 0;
+	int			tmp_logflags;
+	char			*kaddr = NULL;
+
+	ASSERT(whichfork != XFS_COW_FORK);
+	ASSERT(XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_EXTENTS);
+
+	if (xfs_iext_count(ifp) == 0)
+		goto init_local_fork;
+
+	for_each_xfs_iext(ifp, &icur, &got) {
+		del = got;
+		if (isnullstartblock(got.br_startblock)) {
+			error = xfs_bmap_del_extent_delay(ip,
+					whichfork, &icur, &got, &del);
+			if (error)
+				goto out;
+		} else {
+			error = xfs_bmap_del_extent_real(ip, tp, &icur, dfops,
+					NULL, &del, &tmp_logflags, whichfork, 0);
+			if (error)
+				goto out;
+			*logflagsp |= tmp_logflags;
+		}
+	}
+init_local_fork:
+	kaddr = kmap_atomic(page);
+	xfs_init_local_fork(ip, whichfork, kaddr, isize);
+	kunmap_atomic(kaddr);
+	ip->i_d.di_format = XFS_DINODE_FMT_LOCAL;
+	XFS_IFORK_NEXT_SET(ip, whichfork, 0);
+	ip->i_d.di_size = isize;
+	*logflagsp |= (XFS_ILOG_DDATA | XFS_ILOG_CORE);
+out:
+	return error;
+}
+
+
+/*
  * Unmap (remove) blocks from a file.
  * If nexts is nonzero then the number of extents to remove is limited to
  * that value.  If not all extents in the block range can be removed then
diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h
index 9b49ddf99c41..22cd2642f1cd 100644
--- a/fs/xfs/libxfs/xfs_bmap.h
+++ b/fs/xfs/libxfs/xfs_bmap.h
@@ -271,6 +271,10 @@ int	xfs_bmap_map_extent(struct xfs_mount *mp, struct xfs_defer_ops *dfops,
 		struct xfs_inode *ip, struct xfs_bmbt_irec *imap);
 int	xfs_bmap_unmap_extent(struct xfs_mount *mp, struct xfs_defer_ops *dfops,
 		struct xfs_inode *ip, struct xfs_bmbt_irec *imap);
+int	xfs_bmap_extents_to_local(struct xfs_trans *tp, struct xfs_inode *ip,
+		struct xfs_defer_ops *dfops, int *flags, int whichfork,
+		struct page *page);
+void	xfs_bmap_forkoff_reset(struct xfs_inode *ip, int whichfork);
 
 static inline int xfs_bmap_fork_to_state(int whichfork)
 {
-- 
2.11.0