3 files changed, 52 insertions, 2 deletions

diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
index 41ebf52f1bbc..ebde05c9cf62 100644
--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -392,6 +392,7 @@ static struct dentry *ovl_lookup_real_one(struct dentry *connected,
 	 */
 	take_dentry_name_snapshot(&name, real);
 	this = lookup_one_len(name.name.name, connected, name.name.len);
+	release_dentry_name_snapshot(&name);
 	err = PTR_ERR(this);
 	if (IS_ERR(this)) {
 		goto fail;
@@ -406,7 +407,6 @@ static struct dentry *ovl_lookup_real_one(struct dentry *connected,
 	}
 
 out:
-	release_dentry_name_snapshot(&name);
 	dput(parent);
 	inode_unlock(dir);
 	return this;
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 4d53d3b7e5fe..d081faa55e83 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -392,6 +392,51 @@ out_unlock:
 	return ret;
 }
 
+/*
+ * Calling iter_file_splice_write() directly from overlay's f_op may deadlock
+ * due to lock order inversion between pipe->mutex in iter_file_splice_write()
+ * and file_start_write(real.file) in ovl_write_iter().
+ *
+ * So do everything ovl_write_iter() does and call iter_file_splice_write() on
+ * the real file.
+ */
+static ssize_t ovl_splice_write(struct pipe_inode_info *pipe, struct file *out,
+				loff_t *ppos, size_t len, unsigned int flags)
+{
+	struct fd real;
+	const struct cred *old_cred;
+	struct inode *inode = file_inode(out);
+	struct inode *realinode = ovl_inode_real(inode);
+	ssize_t ret;
+
+	inode_lock(inode);
+	/* Update mode */
+	ovl_copyattr(realinode, inode);
+	ret = file_remove_privs(out);
+	if (ret)
+		goto out_unlock;
+
+	ret = ovl_real_fdget(out, &real);
+	if (ret)
+		goto out_unlock;
+
+	old_cred = ovl_override_creds(inode->i_sb);
+	file_start_write(real.file);
+
+	ret = iter_file_splice_write(pipe, real.file, ppos, len, flags);
+
+	file_end_write(real.file);
+	/* Update size */
+	ovl_copyattr(realinode, inode);
+	revert_creds(old_cred);
+	fdput(real);
+
+out_unlock:
+	inode_unlock(inode);
+
+	return ret;
+}
+
 static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 {
 	struct fd real;
@@ -603,7 +648,7 @@ const struct file_operations ovl_file_operations = {
 	.fadvise	= ovl_fadvise,
 	.flush		= ovl_flush,
 	.splice_read    = generic_file_splice_read,
-	.splice_write   = iter_file_splice_write,
+	.splice_write   = ovl_splice_write,
 
 	.copy_file_range	= ovl_copy_file_range,
 	.remap_file_range	= ovl_remap_file_range,
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index e8ad2c2c77dd..150fdf3bc68d 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -481,6 +481,8 @@ static int ovl_cache_update_ino(struct path *path, struct ovl_cache_entry *p)
 	}
 	this = lookup_one_len(p->name, dir, p->len);
 	if (IS_ERR_OR_NULL(this) || !this->d_inode) {
+		/* Mark a stale entry */
+		p->is_whiteout = true;
 		if (IS_ERR(this)) {
 			err = PTR_ERR(this);
 			this = NULL;
@@ -776,6 +778,9 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx)
 				if (err)
 					goto out;
 			}
+		}
+		/* ovl_cache_update_ino() sets is_whiteout on stale entry */
+		if (!p->is_whiteout) {
 			if (!dir_emit(ctx, p->name, p->len, p->ino, p->type))
 				break;
 		}