From: Darrick J. Wong <djwong@xxxxxxxxxx>
Create a new libxfs function to exchange two directory entries.
The upcoming metadata directory feature will need this to replace a
metadata inode directory entry.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
libxfs/xfs_dir2.c | 117 +++++++++++++++++++++++++++++++++++++++++++++++++++++
libxfs/xfs_dir2.h | 3 +
2 files changed, 120 insertions(+)
diff --git a/libxfs/xfs_dir2.c b/libxfs/xfs_dir2.c
index 43b7bc31166..d14e81403ad 100644
--- a/libxfs/xfs_dir2.c
+++ b/libxfs/xfs_dir2.c
@@ -963,3 +963,120 @@ xfs_dir_remove_child(
/* Remove parent pointer. */
return xfs_parent_remove(tp, du->ppargs, dp, name, ip);
}
+
+/*
+ * Exchange the entry (@name1, @ip1) in directory @dp1 with the entry (@name2,
+ * @ip2) in directory @dp2, and update '..' @ip1 and @ip2's entries as needed.
+ * @ip1 and @ip2 need not be of the same type.
+ *
+ * All inodes must have the ILOCK held, and both entries must already exist.
+ */
+int
+xfs_dir_exchange_children(
+ struct xfs_trans *tp,
+ struct xfs_dir_update *du1,
+ struct xfs_dir_update *du2,
+ unsigned int spaceres)
+{
+ struct xfs_inode *dp1 = du1->dp;
+ const struct xfs_name *name1 = du1->name;
+ struct xfs_inode *ip1 = du1->ip;
+ struct xfs_inode *dp2 = du2->dp;
+ const struct xfs_name *name2 = du2->name;
+ struct xfs_inode *ip2 = du2->ip;
+ int ip1_flags = 0;
+ int ip2_flags = 0;
+ int dp2_flags = 0;
+ int error;
+
+ /* Swap inode number for dirent in first parent */
+ error = xfs_dir_replace(tp, dp1, name1, ip2->i_ino, spaceres);
+ if (error)
+ return error;
+
+ /* Swap inode number for dirent in second parent */
+ error = xfs_dir_replace(tp, dp2, name2, ip1->i_ino, spaceres);
+ if (error)
+ return error;
+
+ /*
+ * If we're renaming one or more directories across different parents,
+ * update the respective ".." entries (and link counts) to match the new
+ * parents.
+ */
+ if (dp1 != dp2) {
+ dp2_flags = XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG;
+
+ if (S_ISDIR(VFS_I(ip2)->i_mode)) {
+ error = xfs_dir_replace(tp, ip2, &xfs_name_dotdot,
+ dp1->i_ino, spaceres);
+ if (error)
+ return error;
+
+ /* transfer ip2 ".." reference to dp1 */
+ if (!S_ISDIR(VFS_I(ip1)->i_mode)) {
+ error = xfs_droplink(tp, dp2);
+ if (error)
+ return error;
+ xfs_bumplink(tp, dp1);
+ }
+
+ /*
+ * Although ip1 isn't changed here, userspace needs
+ * to be warned about the change, so that applications
+ * relying on it (like backup ones), will properly
+ * notify the change
+ */
+ ip1_flags |= XFS_ICHGTIME_CHG;
+ ip2_flags |= XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG;
+ }
+
+ if (S_ISDIR(VFS_I(ip1)->i_mode)) {
+ error = xfs_dir_replace(tp, ip1, &xfs_name_dotdot,
+ dp2->i_ino, spaceres);
+ if (error)
+ return error;
+
+ /* transfer ip1 ".." reference to dp2 */
+ if (!S_ISDIR(VFS_I(ip2)->i_mode)) {
+ error = xfs_droplink(tp, dp1);
+ if (error)
+ return error;
+ xfs_bumplink(tp, dp2);
+ }
+
+ /*
+ * Although ip2 isn't changed here, userspace needs
+ * to be warned about the change, so that applications
+ * relying on it (like backup ones), will properly
+ * notify the change
+ */
+ ip1_flags |= XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG;
+ ip2_flags |= XFS_ICHGTIME_CHG;
+ }
+ }
+
+ if (ip1_flags) {
+ xfs_trans_ichgtime(tp, ip1, ip1_flags);
+ xfs_trans_log_inode(tp, ip1, XFS_ILOG_CORE);
+ }
+ if (ip2_flags) {
+ xfs_trans_ichgtime(tp, ip2, ip2_flags);
+ xfs_trans_log_inode(tp, ip2, XFS_ILOG_CORE);
+ }
+ if (dp2_flags) {
+ xfs_trans_ichgtime(tp, dp2, dp2_flags);
+ xfs_trans_log_inode(tp, dp2, XFS_ILOG_CORE);
+ }
+ xfs_trans_ichgtime(tp, dp1, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
+ xfs_trans_log_inode(tp, dp1, XFS_ILOG_CORE);
+
+ /* Schedule parent pointer replacements */
+ error = xfs_parent_replace(tp, du1->ppargs, dp1, name1, dp2, name2,
+ ip1);
+ if (error)
+ return error;
+
+ return xfs_parent_replace(tp, du2->ppargs, dp2, name2, dp1, name1,
+ ip2);
+}
diff --git a/libxfs/xfs_dir2.h b/libxfs/xfs_dir2.h
index 8c8b55b487d..dbca60ec934 100644
--- a/libxfs/xfs_dir2.h
+++ b/libxfs/xfs_dir2.h
@@ -309,4 +309,7 @@ int xfs_dir_add_child(struct xfs_trans *tp, unsigned int resblks,
int xfs_dir_remove_child(struct xfs_trans *tp, unsigned int resblks,
struct xfs_dir_update *du);
+int xfs_dir_exchange_children(struct xfs_trans *tp, struct xfs_dir_update *du1,
+ struct xfs_dir_update *du2, unsigned int spaceres);
+
#endif /* __XFS_DIR2_H__ */
