[PATCH v8 13/20] fs: affs: Initialize filesystem timestamp ranges

From: Deepa Dinamani <deepa.kernel@gmail.com>
To: viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, y2038@lists.linaro.org,
	arnd@arndb.de, dsterba@suse.com
Subject: [PATCH v8 13/20] fs: affs: Initialize filesystem timestamp ranges
Date: Sun, 18 Aug 2019 09:58:10 -0700	[thread overview]
Message-ID: <20190818165817.32634-14-deepa.kernel@gmail.com> (raw)
In-Reply-To: <20190818165817.32634-1-deepa.kernel@gmail.com>

Fill in the appropriate limits to avoid inconsistencies
in the vfs cached inode times when timestamps are
outside the permitted range.

Also fix timestamp calculation to avoid overflow
while converting from days to seconds.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: David Sterba <dsterba@suse.com>
Cc: dsterba@suse.com
---
 fs/affs/amigaffs.c | 2 +-
 fs/affs/amigaffs.h | 3 +++
 fs/affs/inode.c    | 4 ++--
 fs/affs/super.c    | 4 ++++
 4 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/fs/affs/amigaffs.c b/fs/affs/amigaffs.c
index 14a6c1b90c9f..f708c45d5f66 100644
--- a/fs/affs/amigaffs.c
+++ b/fs/affs/amigaffs.c
@@ -375,7 +375,7 @@ affs_secs_to_datestamp(time64_t secs, struct affs_date *ds)
 	u32	 minute;
 	s32	 rem;
 
-	secs -= sys_tz.tz_minuteswest * 60 + ((8 * 365 + 2) * 24 * 60 * 60);
+	secs -= sys_tz.tz_minuteswest * 60 + AFFS_EPOCH_DELTA;
 	if (secs < 0)
 		secs = 0;
 	days    = div_s64_rem(secs, 86400, &rem);
diff --git a/fs/affs/amigaffs.h b/fs/affs/amigaffs.h
index f9bef9056659..81fb396d4dfa 100644
--- a/fs/affs/amigaffs.h
+++ b/fs/affs/amigaffs.h
@@ -32,6 +32,9 @@
 
 #define AFFS_ROOT_BMAPS		25
 
+/* Seconds since Amiga epoch of 1978/01/01 to UNIX */
+#define AFFS_EPOCH_DELTA ((8 * 365 + 2) * 86400LL)
+
 struct affs_date {
 	__be32 days;
 	__be32 mins;
diff --git a/fs/affs/inode.c b/fs/affs/inode.c
index 73598bff8506..a346cf7659f1 100644
--- a/fs/affs/inode.c
+++ b/fs/affs/inode.c
@@ -150,10 +150,10 @@ struct inode *affs_iget(struct super_block *sb, unsigned long ino)
 	}
 
 	inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec
-		       = (be32_to_cpu(tail->change.days) * (24 * 60 * 60) +
+		       = (be32_to_cpu(tail->change.days) * 86400LL +
 		         be32_to_cpu(tail->change.mins) * 60 +
 			 be32_to_cpu(tail->change.ticks) / 50 +
-			 ((8 * 365 + 2) * 24 * 60 * 60)) +
+			 AFFS_EPOCH_DELTA) +
 			 sys_tz.tz_minuteswest * 60;
 	inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = inode->i_atime.tv_nsec = 0;
 	affs_brelse(bh);
diff --git a/fs/affs/super.c b/fs/affs/super.c
index e7d036efbaa1..cc463ae47c12 100644
--- a/fs/affs/super.c
+++ b/fs/affs/super.c
@@ -355,6 +355,10 @@ static int affs_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_op                = &affs_sops;
 	sb->s_flags |= SB_NODIRATIME;
 
+	sb->s_time_gran = NSEC_PER_SEC;
+	sb->s_time_min = sys_tz.tz_minuteswest * 60 + AFFS_EPOCH_DELTA;
+	sb->s_time_max = 86400LL * U32_MAX + 86400 + sb->s_time_min;
+
 	sbi = kzalloc(sizeof(struct affs_sb_info), GFP_KERNEL);
 	if (!sbi)
 		return -ENOMEM;
-- 
2.17.1

