Unverified Commit c69566b1 authored by NeilBrown's avatar NeilBrown Committed by Christian Brauner
Browse files

ovl: narrow locking on ovl_remove_and_whiteout() 



This code:
  performs a lookup_upper
  creates a whiteout object
  renames the whiteout over the result of the lookup

The create and the rename must be locked separately for proposed
directory locking changes.  This patch takes a first step of moving the
lookup out of the locked region.  A subsequent patch will separate the
create from the rename.

Signed-off-by: default avatarNeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250716004725.1206467-17-neil@brown.name


Reviewed-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 241062ae

fs/overlayfs/dir.c

+10 −13
Original line number Diff line number Diff line
@@ -770,15 +770,11 @@ static int ovl_remove_and_whiteout(struct dentry *dentry, 
			goto out;

	}



	err = ovl_lock_rename_workdir(workdir, NULL, upperdir, NULL);

	if (err)

		goto out_dput;



	upper = ovl_lookup_upper(ofs, dentry->d_name.name, upperdir,

	upper = ovl_lookup_upper_unlocked(ofs, dentry->d_name.name, upperdir,

					  dentry->d_name.len);

	err = PTR_ERR(upper);

	if (IS_ERR(upper))

		goto out_unlock;

		goto out_dput;



	err = -ESTALE;

	if ((opaquedir && upper != opaquedir) ||
@@ -787,17 +783,18 @@ static int ovl_remove_and_whiteout(struct dentry *dentry, 
		goto out_dput_upper;

	}



	err = ovl_cleanup_and_whiteout(ofs, upperdir, upper);

	err = ovl_lock_rename_workdir(workdir, NULL, upperdir, upper);

	if (err)

		goto out_d_drop;

		goto out_dput_upper;



	err = ovl_cleanup_and_whiteout(ofs, upperdir, upper);

	if (!err)

		ovl_dir_modified(dentry->d_parent, true);

out_d_drop:



	d_drop(dentry);

	unlock_rename(workdir, upperdir);

out_dput_upper:

	dput(upper);

out_unlock:

	unlock_rename(workdir, upperdir);

out_dput:

	dput(opaquedir);

out: