From d8b9b6ece27fa479e61594c9b4b8277d315cfa77 Mon Sep 17 00:00:00 2001
From: Anthony Iliopoulos <ailiop@suse.com>
Date: Wed, 1 Dec 2021 11:23:46 +0100
Subject: [PATCH] mount: warn only once about timestamp range expiration
Patch-mainline: not yet, submitted 20220119202934.26495-1-ailiop@suse.com
References: bsc#1193000

Commit f8b92ba67c5d ("mount: Add mount warning for impending timestamp
expiry") introduced a mount warning regarding filesystem timestamp
limits, that is printed upon each writable mount or remount.

This can result in a lot of unnecessary messages in the kernel log in
setups where filesystems are being frequently remounted (or mounted
multiple times).

Avoid this by setting a superblock flag which indicates that the warning
has been emitted at least once for any particular mount, as suggested in
[1].

Signed-off-by: Anthony Iliopoulos <ailiop@suse.com>

[1] https://lore.kernel.org/CAHk-=wim6VGnxQmjfK_tDg6fbHYKL4EFkmnTjVr9QnRqjDBAeA@mail.gmail.com/

Acked-by: Anthony Iliopoulos <ailiop@suse.com>

---
 fs/namespace.c     |    2 ++
 include/linux/fs.h |    1 +
 2 files changed, 3 insertions(+)

--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2568,6 +2568,7 @@
 	struct super_block *sb = mnt->mnt_sb;
 
 	if (!__mnt_is_readonly(mnt) &&
+	   (!(sb->s_iflags & SB_I_TS_EXPIRY_WARNED)) &&
 	   (ktime_get_real_seconds() + TIME_UPTIME_SEC_MAX > sb->s_time_max)) {
 		char *buf = (char *)__get_free_page(GFP_KERNEL);
 		char *mntpath = buf ? d_path(mountpoint, buf, PAGE_SIZE) : ERR_PTR(-ENOMEM);
@@ -2582,6 +2583,7 @@
 			tm.tm_year+1900, (unsigned long long)sb->s_time_max);
 
 		free_page((unsigned long)buf);
+		sb->s_iflags |= SB_I_TS_EXPIRY_WARNED;
 	}
 }
 
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1435,6 +1435,7 @@
 #define SB_I_UNTRUSTED_MOUNTER		0x00000040
 
 #define SB_I_SKIP_SYNC	0x00000100	/* Skip superblock at global sync */
+#define SB_I_TS_EXPIRY_WARNED 0x00000400 /* warned about timestamp range expiry */
 
 /* Possible states of 'frozen' field */
 enum {