Patch "libfs: Add simple_offset_rename() API" has been added to the 6.8-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    libfs: Add simple_offset_rename() API

to the 6.8-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     libfs-add-simple_offset_rename-api.patch
and it can be found in the queue-6.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit effb4b859c783a81290bb81f3776659afda37745
Author: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date:   Mon Apr 15 11:20:55 2024 -0400

    libfs: Add simple_offset_rename() API
    
    [ Upstream commit 5a1a25be995e1014abd01600479915683e356f5c ]
    
    I'm about to fix a tmpfs rename bug that requires the use of
    internal simple_offset helpers that are not available in mm/shmem.c
    
    Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20240415152057.4605-3-cel@xxxxxxxxxx
    Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
    Stable-dep-of: ad191eb6d694 ("shmem: Fix shmem_rename2()")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/libfs.c b/fs/libfs.c
index c9516f3e14bb7..bb6731fa63059 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -356,6 +356,27 @@ int simple_offset_empty(struct dentry *dentry)
 	return ret;
 }
 
+/**
+ * simple_offset_rename - handle directory offsets for rename
+ * @old_dir: parent directory of source entry
+ * @old_dentry: dentry of source entry
+ * @new_dir: parent_directory of destination entry
+ * @new_dentry: dentry of destination
+ *
+ * Caller provides appropriate serialization.
+ *
+ * Returns zero on success, a negative errno value on failure.
+ */
+int simple_offset_rename(struct inode *old_dir, struct dentry *old_dentry,
+			 struct inode *new_dir, struct dentry *new_dentry)
+{
+	struct offset_ctx *old_ctx = old_dir->i_op->get_offset_ctx(old_dir);
+	struct offset_ctx *new_ctx = new_dir->i_op->get_offset_ctx(new_dir);
+
+	simple_offset_remove(old_ctx, old_dentry);
+	return simple_offset_add(new_ctx, old_dentry);
+}
+
 /**
  * simple_offset_rename_exchange - exchange rename with directory offsets
  * @old_dir: parent of dentry being moved
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3350f875ca91c..10e32c8ef1e9c 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3268,6 +3268,8 @@ void simple_offset_init(struct offset_ctx *octx);
 int simple_offset_add(struct offset_ctx *octx, struct dentry *dentry);
 void simple_offset_remove(struct offset_ctx *octx, struct dentry *dentry);
 int simple_offset_empty(struct dentry *dentry);
+int simple_offset_rename(struct inode *old_dir, struct dentry *old_dentry,
+			 struct inode *new_dir, struct dentry *new_dentry);
 int simple_offset_rename_exchange(struct inode *old_dir,
 				  struct dentry *old_dentry,
 				  struct inode *new_dir,
diff --git a/mm/shmem.c b/mm/shmem.c
index 0e951fe9f44cc..935f3647bb3a1 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -3434,8 +3434,7 @@ static int shmem_rename2(struct mnt_idmap *idmap,
 			return error;
 	}
 
-	simple_offset_remove(shmem_get_offset_ctx(old_dir), old_dentry);
-	error = simple_offset_add(shmem_get_offset_ctx(new_dir), old_dentry);
+	error = simple_offset_rename(old_dir, old_dentry, new_dir, new_dentry);
 	if (error)
 		return error;