[PATCH 25/64] xfs: create libxfs helper to link a new inode into a directory

["Darrick J. Wong" <djwong@kernel.org>]

From: Darrick J. Wong <djwong@kernel.org>

Source kernel commit: 1fa2e81957cf11620867729fb613b121692ee0d3

Create a new libxfs function to link a newly created inode into a
directory.  The upcoming metadata directory feature will need this to
create a metadata directory tree.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 libxfs/xfs_dir2.c |   53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 libxfs/xfs_dir2.h |   12 ++++++++++++
 2 files changed, 65 insertions(+)


diff --git a/libxfs/xfs_dir2.c b/libxfs/xfs_dir2.c
index 9cf05ec51..e98b28024 100644
--- a/libxfs/xfs_dir2.c
+++ b/libxfs/xfs_dir2.c
@@ -18,6 +18,9 @@
 #include "xfs_errortag.h"
 #include "xfs_trace.h"
 #include "xfs_health.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_trans_space.h"
+#include "xfs_parent.h"
 
 const struct xfs_name xfs_name_dotdot = {
 	.name	= (const unsigned char *)"..",
@@ -755,3 +758,53 @@ xfs_dir2_compname(
 		return xfs_ascii_ci_compname(args, name, len);
 	return xfs_da_compname(args, name, len);
 }
+
+/*
+ * Given a directory @dp, a newly allocated inode @ip, and a @name, link @ip
+ * into @dp under the given @name.  If @ip is a directory, it will be
+ * initialized.  Both inodes must have the ILOCK held and the transaction must
+ * have sufficient blocks reserved.
+ */
+int
+xfs_dir_create_child(
+	struct xfs_trans	*tp,
+	unsigned int		resblks,
+	struct xfs_dir_update	*du)
+{
+	struct xfs_inode	*dp = du->dp;
+	const struct xfs_name	*name = du->name;
+	struct xfs_inode	*ip = du->ip;
+	int			error;
+
+	xfs_assert_ilocked(ip, XFS_ILOCK_EXCL);
+	xfs_assert_ilocked(dp, XFS_ILOCK_EXCL);
+
+	error = xfs_dir_createname(tp, dp, name, ip->i_ino, resblks);
+	if (error) {
+		ASSERT(error != -ENOSPC);
+		return error;
+	}
+
+	xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
+	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
+
+	if (S_ISDIR(VFS_I(ip)->i_mode)) {
+		error = xfs_dir_init(tp, ip, dp);
+		if (error)
+			return error;
+
+		xfs_bumplink(tp, dp);
+	}
+
+	/*
+	 * If we have parent pointers, we need to add the attribute containing
+	 * the parent information now.
+	 */
+	if (du->ppargs) {
+		error = xfs_parent_addname(tp, du->ppargs, dp, name, ip);
+		if (error)
+			return error;
+	}
+
+	return 0;
+}
diff --git a/libxfs/xfs_dir2.h b/libxfs/xfs_dir2.h
index 6dbe6e9ec..a1ba6fd0a 100644
--- a/libxfs/xfs_dir2.h
+++ b/libxfs/xfs_dir2.h
@@ -309,4 +309,16 @@ static inline unsigned char xfs_ascii_ci_xfrm(unsigned char c)
 	return c;
 }
 
+struct xfs_parent_args;
+
+struct xfs_dir_update {
+	struct xfs_inode	*dp;
+	const struct xfs_name	*name;
+	struct xfs_inode	*ip;
+	struct xfs_parent_args	*ppargs;
+};
+
+int xfs_dir_create_child(struct xfs_trans *tp, unsigned int resblks,
+		struct xfs_dir_update *du);
+
 #endif	/* __XFS_DIR2_H__ */