xfs: create a new inode fork block unmap helper

Create a new helper to unmap blocks from an inode's fork.

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

1 files changed, 40 insertions, 1 deletions

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index a073ca877ced..523926fe50eb 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -5239,7 +5239,7 @@ xfs_bmap_del_extent_real(
  * that value.  If not all extents in the block range can be removed then
  * *done is set.
  */
-int						/* error */
+static int
 __xfs_bunmapi(
 	struct xfs_trans	*tp,		/* transaction pointer */
 	struct xfs_inode	*ip,		/* incore inode */
@@ -6220,3 +6220,42 @@ xfs_bmap_validate_extent(
 	return xfs_bmap_validate_extent_raw(ip->i_mount,
 			XFS_IS_REALTIME_INODE(ip), whichfork, irec);
 }
+
+/*
+ * Used in xfs_itruncate_extents().  This is the maximum number of extents
+ * freed from a file in a single transaction.
+ */
+#define	XFS_ITRUNC_MAX_EXTENTS	2
+
+/*
+ * Unmap every extent in part of an inode's fork.  We don't do any higher level
+ * invalidation work at all.
+ */
+int
+xfs_bunmapi_range(
+	struct xfs_trans	**tpp,
+	struct xfs_inode	*ip,
+	uint32_t		flags,
+	xfs_fileoff_t		startoff,
+	xfs_fileoff_t		endoff)
+{
+	xfs_filblks_t		unmap_len = endoff - startoff + 1;
+	int			error = 0;
+
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+
+	while (unmap_len > 0) {
+		ASSERT((*tpp)->t_highest_agno == NULLAGNUMBER);
+		error = __xfs_bunmapi(*tpp, ip, startoff, &unmap_len, flags,
+				XFS_ITRUNC_MAX_EXTENTS);
+		if (error)
+			goto out;
+
+		/* free the just unmapped extents */
+		error = xfs_defer_finish(tpp);
+		if (error)
+			goto out;
+	}
+out:
+	return error;
+}