fs: new helper: simple_rename_timestamp

A rename potentially involves updating 4 different inode timestamps. Add
a function that handles the details sanely, and convert the libfs.c
callers to use it.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Message-Id: <20230705185812.579118-3-jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/libfs.c b/fs/libfs.c
index 5b85131..ea0a845 100644 (file)
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -444,6 +444,31 @@ int simple_rmdir(struct inode *dir, struct dentry *dentry)
 }
 EXPORT_SYMBOL(simple_rmdir);
 
+/**
+ * simple_rename_timestamp - update the various inode timestamps for rename
+ * @old_dir: old parent directory
+ * @old_dentry: dentry that is being renamed
+ * @new_dir: new parent directory
+ * @new_dentry: target for rename
+ *
+ * POSIX mandates that the old and new parent directories have their ctime and
+ * mtime updated, and that inodes of @old_dentry and @new_dentry (if any), have
+ * their ctime updated.
+ */
+void simple_rename_timestamp(struct inode *old_dir, struct dentry *old_dentry,
+                            struct inode *new_dir, struct dentry *new_dentry)
+{
+       struct inode *newino = d_inode(new_dentry);
+
+       old_dir->i_mtime = inode_set_ctime_current(old_dir);
+       if (new_dir != old_dir)
+               new_dir->i_mtime = inode_set_ctime_current(new_dir);
+       inode_set_ctime_current(d_inode(old_dentry));
+       if (newino)
+               inode_set_ctime_current(newino);
+}
+EXPORT_SYMBOL_GPL(simple_rename_timestamp);
+
 int simple_rename_exchange(struct inode *old_dir, struct dentry *old_dentry,
                           struct inode *new_dir, struct dentry *new_dentry)
 {
@@ -459,11 +484,7 @@ int simple_rename_exchange(struct inode *old_dir, struct dentry *old_dentry,
                        inc_nlink(old_dir);
                }
        }
-       old_dir->i_ctime = old_dir->i_mtime =
-       new_dir->i_ctime = new_dir->i_mtime =
-       d_inode(old_dentry)->i_ctime =
-       d_inode(new_dentry)->i_ctime = current_time(old_dir);
-
+       simple_rename_timestamp(old_dir, old_dentry, new_dir, new_dentry);
        return 0;
 }
 EXPORT_SYMBOL_GPL(simple_rename_exchange);
@@ -472,7 +493,6 @@ int simple_rename(struct mnt_idmap *idmap, struct inode *old_dir,
                  struct dentry *old_dentry, struct inode *new_dir,
                  struct dentry *new_dentry, unsigned int flags)
 {
-       struct inode *inode = d_inode(old_dentry);
        int they_are_dirs = d_is_dir(old_dentry);
 
        if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
@@ -495,9 +515,7 @@ int simple_rename(struct mnt_idmap *idmap, struct inode *old_dir,
                inc_nlink(new_dir);
        }
 
-       old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime =
-               new_dir->i_mtime = inode->i_ctime = current_time(old_dir);
-
+       simple_rename_timestamp(old_dir, old_dentry, new_dir, new_dentry);
        return 0;
 }
 EXPORT_SYMBOL(simple_rename);

diff --git a/include/linux/fs.h b/include/linux/fs.h
index d41bfcb..42755cb 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2977,6 +2977,8 @@ extern int simple_open(struct inode *inode, struct file *file);
 extern int simple_link(struct dentry *, struct inode *, struct dentry *);
 extern int simple_unlink(struct inode *, struct dentry *);
 extern int simple_rmdir(struct inode *, struct dentry *);
+void simple_rename_timestamp(struct inode *old_dir, struct dentry *old_dentry,
+                            struct inode *new_dir, struct dentry *new_dentry);
 extern int simple_rename_exchange(struct inode *old_dir, struct dentry *old_dentry,
                                  struct inode *new_dir, struct dentry *new_dentry);
 extern int simple_rename(struct mnt_idmap *, struct inode *,