From 09d56cc88c247036da5756fd552f2cb2af8d8c5e Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 16 Jul 2025 10:44:30 +1000 Subject: [PATCH] ovl: narrow locking in ovl_check_rename_whiteout() ovl_check_rename_whiteout() now only holds the directory lock when needed, and takes it again if necessary. This makes way for future changes where locks are taken on individual dentries rather than the whole directory. Reviewed-by: Amir Goldstein Signed-off-by: NeilBrown Link: https://lore.kernel.org/20250716004725.1206467-20-neil@brown.name Signed-off-by: Christian Brauner --- fs/overlayfs/super.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 4c3736bf2db4d..0d765aa66bd2a 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -556,7 +556,6 @@ out: static int ovl_check_rename_whiteout(struct ovl_fs *ofs) { struct dentry *workdir = ofs->workdir; - struct inode *dir = d_inode(workdir); struct dentry *temp; struct dentry *dest; struct dentry *whiteout; @@ -577,19 +576,22 @@ static int ovl_check_rename_whiteout(struct ovl_fs *ofs) err = PTR_ERR(dest); if (IS_ERR(dest)) { dput(temp); - goto out_unlock; + ovl_parent_unlock(workdir); + return err; } /* Name is inline and stable - using snapshot as a copy helper */ take_dentry_name_snapshot(&name, temp); err = ovl_do_rename(ofs, workdir, temp, workdir, dest, RENAME_WHITEOUT); + ovl_parent_unlock(workdir); if (err) { if (err == -EINVAL) err = 0; goto cleanup_temp; } - whiteout = ovl_lookup_upper(ofs, name.name.name, workdir, name.name.len); + whiteout = ovl_lookup_upper_unlocked(ofs, name.name.name, + workdir, name.name.len); err = PTR_ERR(whiteout); if (IS_ERR(whiteout)) goto cleanup_temp; @@ -598,18 +600,15 @@ static int ovl_check_rename_whiteout(struct ovl_fs *ofs) /* Best effort cleanup of whiteout and temp file */ if (err) - ovl_cleanup(ofs, dir, whiteout); + ovl_cleanup_unlocked(ofs, workdir, whiteout); dput(whiteout); cleanup_temp: - ovl_cleanup(ofs, dir, temp); + ovl_cleanup_unlocked(ofs, workdir, temp); release_dentry_name_snapshot(&name); dput(temp); dput(dest); -out_unlock: - ovl_parent_unlock(workdir); - return err; } -- 2.47.2