[PATCH 14/20] ovl: change ovl_workdir_cleanup() to take dir lock as needed.

[NeilBrown <neil@xxxxxxxxxx>]

Rather than calling ovl_workdir_cleanup() with the dir already locked,
change it to take the dir lock only when needed.

Signed-off-by: NeilBrown <neil@xxxxxxxxxx>
---
 fs/overlayfs/overlayfs.h |  2 +-
 fs/overlayfs/readdir.c   | 30 +++++++++++++-----------------
 fs/overlayfs/super.c     |  4 +---
 3 files changed, 15 insertions(+), 21 deletions(-)

diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index ec804d6bb2ef..ca74be44dddd 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -738,7 +738,7 @@ void ovl_cleanup_whiteouts(struct ovl_fs *ofs, struct dentry *upper,
 void ovl_cache_free(struct list_head *list);
 void ovl_dir_cache_free(struct inode *inode);
 int ovl_check_d_type_supported(const struct path *realpath);
-int ovl_workdir_cleanup(struct ovl_fs *ofs, struct inode *dir,
+int ovl_workdir_cleanup(struct ovl_fs *ofs, struct dentry *parent,
 			struct vfsmount *mnt, struct dentry *dentry, int level);
 int ovl_indexdir_cleanup(struct ovl_fs *ofs);
 
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index b3d44bf56c78..6cc5f885e036 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -1096,7 +1096,6 @@ static int ovl_workdir_cleanup_recurse(struct ovl_fs *ofs, const struct path *pa
 				       int level)
 {
 	int err;
-	struct inode *dir = path->dentry->d_inode;
 	LIST_HEAD(list);
 	struct ovl_cache_entry *p;
 	struct ovl_readdir_data rdd = {
@@ -1139,11 +1138,9 @@ static int ovl_workdir_cleanup_recurse(struct ovl_fs *ofs, const struct path *pa
 		dentry = ovl_lookup_upper_unlocked(ofs, p->name, path->dentry, p->len);
 		if (IS_ERR(dentry))
 			continue;
-		if (dentry->d_inode) {
-			inode_lock_nested(dir, I_MUTEX_PARENT);
-			err = ovl_workdir_cleanup(ofs, dir, path->mnt, dentry, level);
-			inode_unlock(dir);
-		}
+		if (dentry->d_inode)
+			err = ovl_workdir_cleanup(ofs, path->dentry, path->mnt,
+						  dentry, level);
 		dput(dentry);
 		if (err)
 			break;
@@ -1153,24 +1150,25 @@ static int ovl_workdir_cleanup_recurse(struct ovl_fs *ofs, const struct path *pa
 	return err;
 }
 
-int ovl_workdir_cleanup(struct ovl_fs *ofs, struct inode *dir,
+int ovl_workdir_cleanup(struct ovl_fs *ofs, struct dentry *parent,
 			struct vfsmount *mnt, struct dentry *dentry, int level)
 {
 	int err;
 
-	if (!d_is_dir(dentry) || level > 1) {
-		return ovl_cleanup(ofs, dir, dentry);
-	}
+	if (!d_is_dir(dentry) || level > 1)
+		return ovl_cleanup_unlocked(ofs, parent, dentry);
 
-	err = ovl_do_rmdir(ofs, dir, dentry);
+	err = parent_lock(parent, dentry);
+	if (err)
+		return err;
+	err = ovl_do_rmdir(ofs, parent->d_inode, dentry);
+	parent_unlock(parent);
 	if (err) {
 		struct path path = { .mnt = mnt, .dentry = dentry };
 
-		inode_unlock(dir);
 		err = ovl_workdir_cleanup_recurse(ofs, &path, level + 1);
-		inode_lock_nested(dir, I_MUTEX_PARENT);
 		if (!err)
-			err = ovl_cleanup(ofs, dir, dentry);
+			err = ovl_cleanup_unlocked(ofs, parent, dentry);
 	}
 
 	return err;
@@ -1210,9 +1208,7 @@ int ovl_indexdir_cleanup(struct ovl_fs *ofs)
 		}
 		/* Cleanup leftover from index create/cleanup attempt */
 		if (index->d_name.name[0] == '#') {
-			inode_lock_nested(dir, I_MUTEX_PARENT);
-			err = ovl_workdir_cleanup(ofs, dir, path.mnt, index, 1);
-			inode_unlock(dir);
+			err = ovl_workdir_cleanup(ofs, indexdir, path.mnt, index, 1);
 			if (err)
 				break;
 			goto next;
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 239ae1946edf..23f43f8131dd 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -319,9 +319,7 @@ static struct dentry *ovl_workdir_create(struct ovl_fs *ofs,
 				goto out;
 
 			retried = true;
-			inode_lock_nested(dir, I_MUTEX_PARENT);
-			err = ovl_workdir_cleanup(ofs, dir, mnt, work, 0);
-			inode_unlock(dir);
+			err = ovl_workdir_cleanup(ofs, ofs->workbasedir, mnt, work, 0);
 			dput(work);
 			if (err == -EINVAL) {
 				work = ERR_PTR(err);
-- 
2.49.0