linux-kernel - [PATCH] proc: update i_atime when reading files

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Message-Id: <20190221163714.22330-1-jcline@redhat.com>
Date:   Thu, 21 Feb 2019 11:37:14 -0500
From:   Jeremy Cline <jcline@...hat.com>
To:     Alexey Dobriyan <adobriyan@...il.com>
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jeremy Cline <jcline@...hat.com>,
        David Both <dboth@...lennium-technology.com>
Subject: [PATCH] proc: update i_atime when reading files

Prior to commit 1da4d377f943 ("proc: revalidate misc dentries"), the
access, modify, and change times of files in /proc were just the current
time. Now the mtime and ctime values change mostly as a user would
expect, but the atime isn't updated when the file read. This patch
updates the access time of /proc files when they are read.

Reported-by: David Both <dboth@...lennium-technology.com>
Signed-off-by: Jeremy Cline <jcline@...hat.com>
---
 fs/proc/inode.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index da649ccd6804..34d8603b9aa1 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -221,12 +221,17 @@ static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
 static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 {
 	ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);
-	struct proc_dir_entry *pde = PDE(file_inode(file));
+	struct inode *inode = file_inode(file);
+	struct proc_dir_entry *pde = PDE(inode);
 	ssize_t rv = -EIO;
 	if (use_pde(pde)) {
 		read = pde->proc_fops->read;
-		if (read)
+		if (read) {
 			rv = read(file, buf, count, ppos);
+			if (rv >= 0)
+				inode->i_atime = current_time(inode);
+		}
+
 		unuse_pde(pde);
 	}
 	return rv;
-- 
2.20.1