Unverified Commit ad191eb6 authored by Chuck Lever's avatar Chuck Lever Committed by Christian Brauner
Browse files

shmem: Fix shmem_rename2() 

When renaming onto an existing directory entry, user space expects
the replacement entry to have the same directory offset as the
original one.

Link: https://gitlab.alpinelinux.org/alpine/aports/-/issues/15966


Fixes: a2e45955 ("shmem: stable directory offsets")
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/20240415152057.4605-4-cel@kernel.org


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 5a1a25be

fs/libfs.c

+9 −0
Original line number Diff line number Diff line
@@ -366,6 +366,9 @@ int simple_offset_empty(struct dentry *dentry) 
 *

 * Caller provides appropriate serialization.

 *

 * User space expects the directory offset value of the replaced

 * (new) directory entry to be unchanged after a rename.

 *

 * Returns zero on success, a negative errno value on failure.

 */

int simple_offset_rename(struct inode *old_dir, struct dentry *old_dentry,
@@ -373,8 +376,14 @@ int simple_offset_rename(struct inode *old_dir, struct dentry *old_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);

	long new_offset = dentry2offset(new_dentry);



	simple_offset_remove(old_ctx, old_dentry);



	if (new_offset) {

		offset_set(new_dentry, 0);

		return simple_offset_replace(new_ctx, old_dentry, new_offset);

	}

	return simple_offset_add(new_ctx, old_dentry);

}