linux-kernel - [PATCH] fs/namei: Don't update atime when some errors occur in get

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Message-Id: <20231205071733.334474-1-gehao@kylinos.cn>
Date:   Tue,  5 Dec 2023 15:17:33 +0800
From:   Hao Ge <gehao@...inos.cn>
To:     viro@...iv.linux.org.uk, brauner@...nel.org
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        gehao618@....com, Hao Ge <gehao@...inos.cn>
Subject: [PATCH] fs/namei: Don't update atime when some errors occur in get_link

Perhaps we have some errors occur(like security),then we don't update
atime,because we didn't actually access it

Signed-off-by: Hao Ge <gehao@...inos.cn>
---
 fs/namei.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 71c13b2990b4..033d36d5c1c5 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1779,15 +1779,6 @@ static const char *pick_link(struct nameidata *nd, struct path *link,
 			unlikely(link->mnt->mnt_flags & MNT_NOSYMFOLLOW))
 		return ERR_PTR(-ELOOP);
 
-	if (!(nd->flags & LOOKUP_RCU)) {
-		touch_atime(&last->link);
-		cond_resched();
-	} else if (atime_needs_update(&last->link, inode)) {
-		if (!try_to_unlazy(nd))
-			return ERR_PTR(-ECHILD);
-		touch_atime(&last->link);
-	}
-
 	error = security_inode_follow_link(link->dentry, inode,
 					   nd->flags & LOOKUP_RCU);
 	if (unlikely(error))
@@ -1810,6 +1801,16 @@ static const char *pick_link(struct nameidata *nd, struct path *link,
 		if (IS_ERR(res))
 			return res;
 	}
+
+	if (!(nd->flags & LOOKUP_RCU)) {
+		touch_atime(&last->link);
+		cond_resched();
+	} else if (atime_needs_update(&last->link, inode)) {
+		if (!try_to_unlazy(nd))
+			return ERR_PTR(-ECHILD);
+		touch_atime(&last->link);
+	}
+
 	if (*res == '/') {
 		error = nd_jump_root(nd);
 		if (unlikely(error))
-- 
2.25.1