From: Jan Kara <jack@suse.cz>
Date: Thu, 12 Nov 2009 14:42:08 +0000 (+0100)
Subject: quota: Fix WARN_ON in lookup_one_len
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=c56818d7dc976a7392be82e8e04fe26347d591f3;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

quota: Fix WARN_ON in lookup_one_len

We should hold i_mutex when looking up quota files for journaled quotas,
otherwise a WARN_ON in lookup_one_len triggers. The fact that we didn't
hold i_mutex previously probably could not lead to a real bug since the
filesystem is just being mounted / remounted read-write and thus the
root directory cannot change anyway but it's definitely cleaner with
i_mutex.

Reported-by: Bastien ROUCARIES <roucaries.bastien@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
---

diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index eb5a755718f6..cd6bb9a33c13 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -2164,7 +2164,9 @@ int vfs_quota_on_mount(struct super_block *sb, char *qf_name,
 	struct dentry *dentry;
 	int error;
 
+	mutex_lock(&sb->s_root->d_inode->i_mutex);
 	dentry = lookup_one_len(qf_name, sb->s_root, strlen(qf_name));
+	mutex_unlock(&sb->s_root->d_inode->i_mutex);
 	if (IS_ERR(dentry))
 		return PTR_ERR(dentry);