[PATCH 1/2] xfs: introduce xfs_bmap_split_da_extent

[yu kuai]

Add a new function xfs_bmap_split_da_extent to split a delalloc extent
into two delalloc extents.

Signed-off-by: yu kuai <yukuai3@xxxxxxxxxx>
---
 fs/xfs/libxfs/xfs_bmap.c | 26 ++++++++++++++++++++++++--
 fs/xfs/libxfs/xfs_bmap.h |  1 +
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 4c2e046fbfad..8247054c1e2b 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -6117,7 +6117,7 @@ xfs_bmap_split_extent_at(
 	/*
 	 * Convert to a btree if necessary.
 	 */
-	if (xfs_bmap_needs_btree(ip, whichfork)) {
+	if (tp && xfs_bmap_needs_btree(ip, whichfork)) {
 		int tmp_logflags; /* partial log flag return val */
 
 		ASSERT(cur == NULL);
@@ -6132,7 +6132,7 @@ xfs_bmap_split_extent_at(
 		xfs_btree_del_cursor(cur, error);
 	}
 
-	if (logflags)
+	if (tp && logflags)
 		xfs_trans_log_inode(tp, ip, logflags);
 	return error;
 }
@@ -6165,6 +6165,28 @@ xfs_bmap_split_extent(
 	return error;
 }
 
+/*
+ * Splits a delalloc extent into two delalloc extents at split_fsb block
+ * such that it is the first block of the current_ext. Caller has to make
+ * sure split_fsb belong to a delalloc extent.
+ * If split_fsb is not the first block of the extent, caller need to sub
+ * the @ip->i_d.di_nextents to prevent crash in log recovery.
+ */
+int
+xfs_bmap_split_da_extent(
+	struct xfs_inode        *ip,
+	xfs_fileoff_t           split_fsb)
+{
+	struct xfs_trans        *tp = NULL;
+	int error;
+
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
+	error = xfs_bmap_split_extent_at(tp, ip, split_fsb);
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
+	return error;
+}
+
 /* Deferred mapping is only for real extents in the data fork. */
 static bool
 xfs_bmap_is_update_needed(
diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h
index 14d25e0b7d9c..d8d969aa17ef 100644
--- a/fs/xfs/libxfs/xfs_bmap.h
+++ b/fs/xfs/libxfs/xfs_bmap.h
@@ -223,6 +223,7 @@ int	xfs_bmap_insert_extents(struct xfs_trans *tp, struct xfs_inode *ip,
 		xfs_fileoff_t *next_fsb, xfs_fileoff_t offset_shift_fsb,
 		bool *done, xfs_fileoff_t stop_fsb);
 int	xfs_bmap_split_extent(struct xfs_inode *ip, xfs_fileoff_t split_offset);
+int	xfs_bmap_split_da_extent(struct xfs_inode *ip, xfs_fileoff_t split_offset);
 int	xfs_bmapi_reserve_delalloc(struct xfs_inode *ip, int whichfork,
 		xfs_fileoff_t off, xfs_filblks_t len, xfs_filblks_t prealloc,
 		struct xfs_bmbt_irec *got, struct xfs_iext_cursor *cur,
-- 
2.17.2