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 <darrick.wong@oracle.com>

2 files changed, 46 insertions, 0 deletions

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 39dbc93374dc..5be389bfaf3f 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -6227,3 +6227,46 @@ 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,
+	int			whichfork,
+	xfs_fileoff_t		startoff,
+	xfs_filblks_t		unmap_len,
+	int			bunmapi_flags)
+{
+	int			error = 0;
+
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+
+	bunmapi_flags |= xfs_bmapi_aflag(whichfork);
+	while (unmap_len > 0) {
+		ASSERT((*tpp)->t_firstblock == NULLFSBLOCK);
+		error = __xfs_bunmapi(*tpp, ip, startoff, &unmap_len,
+				bunmapi_flags, XFS_ITRUNC_MAX_EXTENTS);
+		if (error)
+			goto out;
+
+		/*
+		 * Duplicate the transaction that has the permanent
+		 * reservation and commit the old transaction.
+		 */
+		error = xfs_defer_finish(tpp);
+		if (error)
+			goto out;
+	}
+out:
+	return error;
+}
diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h
index b857762fac55..cf460d3654b5 100644
--- a/fs/xfs/libxfs/xfs_bmap.h
+++ b/fs/xfs/libxfs/xfs_bmap.h
@@ -279,5 +279,8 @@ xfs_failaddr_t xfs_bmap_validate_extent(struct xfs_inode *ip, int whichfork,
 int	xfs_bmapi_remap(struct xfs_trans *tp, struct xfs_inode *ip,
 		xfs_fileoff_t bno, xfs_filblks_t len, xfs_fsblock_t startblock,
 		int flags);
+int	xfs_bunmapi_range(struct xfs_trans **tpp, struct xfs_inode *ip,
+		int whichfork, xfs_fileoff_t startoff, xfs_filblks_t unmap_len,
+		int bunmapi_flags);
 
 #endif	/* __XFS_BMAP_H__ */