Merge tag 'y2038-vfs' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground

Pull y2038 vfs updates from Arnd Bergmann:
"Add inode timestamp clamping.

This series from Deepa Dinamani adds a per-superblock minimum/maximum
timestamp limit for a file system, and clamps timestamps as they are
written, to avoid random behavior from integer overflow as well as
having different time stamps on disk vs in memory.

At mount time, a warning is now printed for any file system that can
represent current timestamps but not future timestamps more than 30
years into the future, similar to the arbitrary 30 year limit that was
added to settimeofday().

This was picked as a compromise to warn users to migrate to other file
systems (e.g. ext4 instead of ext3) when they need the file system to
survive beyond 2038 (or similar limits in other file systems), but not
get in the way of normal usage"

* tag 'y2038-vfs' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground:
ext4: Reduce ext4 timestamp warnings
isofs: Initialize filesystem timestamp ranges
pstore: fs superblock limits
fs: omfs: Initialize filesystem timestamp ranges
fs: hpfs: Initialize filesystem timestamp ranges
fs: ceph: Initialize filesystem timestamp ranges
fs: sysv: Initialize filesystem timestamp ranges
fs: affs: Initialize filesystem timestamp ranges
fs: fat: Initialize filesystem timestamp ranges
fs: cifs: Initialize filesystem timestamp ranges
fs: nfs: Initialize filesystem timestamp ranges
ext4: Initialize timestamps limits
9p: Fill min and max timestamps in sb
fs: Fill in max and min timestamps in superblock
utimes: Clamp the timestamps before update
mount: Add mount warning for impending timestamp expiry
timestamp_truncate: Replace users of timespec64_trunc
vfs: Add timestamp_truncate() api
vfs: Add file timestamp range support

fs/9p/vfs_super.c

···
 	if (v9fs_proto_dotl(v9ses)) {
 		sb->s_op = &v9fs_super_ops_dotl;
 		sb->s_xattr = v9fs_xattr_handlers;
-	} else
+	} else {
 		sb->s_op = &v9fs_super_ops;
+		sb->s_time_max = U32_MAX;
+	}
+
+	sb->s_time_min = 0;
 
 	ret = super_setup_bdi(sb);
 	if (ret)

fs/affs/amigaffs.c

···
 	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);

fs/affs/amigaffs.h

···
 
 #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;

fs/affs/inode.c

···
 	}
 
 	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);

fs/affs/super.c

···
 	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;

fs/attr.c

···
 		inode->i_uid = attr->ia_uid;
 	if (ia_valid & ATTR_GID)
 		inode->i_gid = attr->ia_gid;
-	if (ia_valid & ATTR_ATIME)
-		inode->i_atime = timespec64_trunc(attr->ia_atime,
-						  inode->i_sb->s_time_gran);
-	if (ia_valid & ATTR_MTIME)
-		inode->i_mtime = timespec64_trunc(attr->ia_mtime,
-						  inode->i_sb->s_time_gran);
-	if (ia_valid & ATTR_CTIME)
-		inode->i_ctime = timespec64_trunc(attr->ia_ctime,
-						  inode->i_sb->s_time_gran);
+	if (ia_valid & ATTR_ATIME) {
+		inode->i_atime = timestamp_truncate(attr->ia_atime,
+						  inode);
+	}
+	if (ia_valid & ATTR_MTIME) {
+		inode->i_mtime = timestamp_truncate(attr->ia_mtime,
+						  inode);
+	}
+	if (ia_valid & ATTR_CTIME) {
+		inode->i_ctime = timestamp_truncate(attr->ia_ctime,
+						  inode);
+	}
 	if (ia_valid & ATTR_MODE) {
 		umode_t mode = attr->ia_mode;
 

fs/befs/linuxvfs.c

···
 	sb_set_blocksize(sb, (ulong) befs_sb->block_size);
 	sb->s_op = &befs_sops;
 	sb->s_export_op = &befs_export_operations;
+	sb->s_time_min = 0;
+	sb->s_time_max = 0xffffffffffffll;
 	root = befs_iget(sb, iaddr2blockno(sb, &(befs_sb->root_dir)));
 	if (IS_ERR(root)) {
 		ret = PTR_ERR(root);

fs/bfs/inode.c

···
 		return -ENOMEM;
 	mutex_init(&info->bfs_lock);
 	s->s_fs_info = info;
+	s->s_time_min = 0;
+	s->s_time_max = U32_MAX;
 
 	sb_set_blocksize(s, BFS_BSIZE);
 

fs/ceph/super.c

···
 	s->s_export_op = &ceph_export_ops;
 
 	s->s_time_gran = 1;
+	s->s_time_min = 0;
+	s->s_time_max = U32_MAX;
 
 	ret = set_anon_super(s, NULL);  /* what is that second arg for? */
 	if (ret != 0)

fs/cifs/cifsfs.c

···
 #include "dfs_cache.h"
 #endif
 
+/*
+ * DOS dates from 1980/1/1 through 2107/12/31
+ * Protocol specifications indicate the range should be to 119, which
+ * limits maximum year to 2099. But this range has not been checked.
+ */
+#define SMB_DATE_MAX (127<<9 | 12<<5 | 31)
+#define SMB_DATE_MIN (0<<9 | 1<<5 | 1)
+#define SMB_TIME_MAX (23<<11 | 59<<5 | 29)
+
 int cifsFYI = 0;
 bool traceSMB;
 bool enable_oplocks = true;
···
 	struct inode *inode;
 	struct cifs_sb_info *cifs_sb;
 	struct cifs_tcon *tcon;
+	struct timespec64 ts;
 	int rc = 0;
 
 	cifs_sb = CIFS_SB(sb);
···
 
 	/* BB FIXME fix time_gran to be larger for LANMAN sessions */
 	sb->s_time_gran = 100;
+
+	if (tcon->unix_ext) {
+		ts = cifs_NTtimeToUnix(0);
+		sb->s_time_min = ts.tv_sec;
+		ts = cifs_NTtimeToUnix(cpu_to_le64(S64_MAX));
+		sb->s_time_max = ts.tv_sec;
+	} else {
+		ts = cnvrtDosUnixTm(cpu_to_le16(SMB_DATE_MIN), 0, 0);
+		sb->s_time_min = ts.tv_sec;
+		ts = cnvrtDosUnixTm(cpu_to_le16(SMB_DATE_MAX), cpu_to_le16(SMB_TIME_MAX), 0);
+		sb->s_time_max = ts.tv_sec;
+	}
 
 	sb->s_magic = CIFS_MAGIC_NUMBER;
 	sb->s_op = &cifs_super_ops;

fs/cifs/netmisc.c

···
 struct timespec64 cnvrtDosUnixTm(__le16 le_date, __le16 le_time, int offset)
 {
 	struct timespec64 ts;
-	time64_t sec;
-	int min, days, month, year;
+	time64_t sec, days;
+	int min, day, month, year;
 	u16 date = le16_to_cpu(le_date);
 	u16 time = le16_to_cpu(le_time);
 	SMB_TIME *st = (SMB_TIME *)&time;
···
 	sec += 60 * 60 * st->Hours;
 	if (st->Hours > 24)
 		cifs_dbg(VFS, "illegal hours %d\n", st->Hours);
-	days = sd->Day;
+	day = sd->Day;
 	month = sd->Month;
-	if (days < 1 || days > 31 || month < 1 || month > 12) {
-		cifs_dbg(VFS, "illegal date, month %d day: %d\n", month, days);
-		days = clamp(days, 1, 31);
+	if (day < 1 || day > 31 || month < 1 || month > 12) {
+		cifs_dbg(VFS, "illegal date, month %d day: %d\n", month, day);
+		day = clamp(day, 1, 31);
 		month = clamp(month, 1, 12);
 	}
 	month -= 1;
-	days += total_days_of_prev_months[month];
+	days = day + total_days_of_prev_months[month];
 	days += 3652; /* account for difference in days between 1980 and 1970 */
 	year = sd->Year;
 	days += year * 365;

fs/coda/inode.c

···
 	sb->s_magic = CODA_SUPER_MAGIC;
 	sb->s_op = &coda_super_operations;
 	sb->s_d_op = &coda_dentry_operations;
+	sb->s_time_gran = 1;
+	sb->s_time_min = S64_MIN;
+	sb->s_time_max = S64_MAX;
 
 	error = super_setup_bdi(sb);
 	if (error)

fs/configfs/inode.c

···
 	if (ia_valid & ATTR_GID)
 		sd_iattr->ia_gid = iattr->ia_gid;
 	if (ia_valid & ATTR_ATIME)
-		sd_iattr->ia_atime = timespec64_trunc(iattr->ia_atime,
-						      inode->i_sb->s_time_gran);
+		sd_iattr->ia_atime = timestamp_truncate(iattr->ia_atime,
+						      inode);
 	if (ia_valid & ATTR_MTIME)
-		sd_iattr->ia_mtime = timespec64_trunc(iattr->ia_mtime,
-						      inode->i_sb->s_time_gran);
+		sd_iattr->ia_mtime = timestamp_truncate(iattr->ia_mtime,
+						      inode);
 	if (ia_valid & ATTR_CTIME)
-		sd_iattr->ia_ctime = timespec64_trunc(iattr->ia_ctime,
-						      inode->i_sb->s_time_gran);
+		sd_iattr->ia_ctime = timestamp_truncate(iattr->ia_ctime,
+						      inode);
 	if (ia_valid & ATTR_MODE) {
 		umode_t mode = iattr->ia_mode;
 

fs/cramfs/inode.c

···
 
 	/* Set it all up.. */
 	sb->s_flags |= SB_RDONLY;
+	sb->s_time_min = 0;
+	sb->s_time_max = 0;
 	sb->s_op = &cramfs_ops;
 	root = get_cramfs_inode(sb, cramfs_root, 0);
 	if (IS_ERR(root))

fs/efs/super.c

···
 	if (!sb)
 		return -ENOMEM;
 	s->s_fs_info = sb;
+	s->s_time_min = 0;
+	s->s_time_max = U32_MAX;
  
 	s->s_magic		= EFS_SUPER_MAGIC;
 	if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {

fs/ext2/super.c

···
 
 	sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 	sb->s_max_links = EXT2_LINK_MAX;
+	sb->s_time_min = S32_MIN;
+	sb->s_time_max = S32_MAX;
 
 	if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 		sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;

fs/ext4/ext4.h

···
 
 #define EXT4_INODE_SET_XTIME(xtime, inode, raw_inode)				\
 do {										\
-	(raw_inode)->xtime = cpu_to_le32((inode)->xtime.tv_sec);		\
 	if (EXT4_FITS_IN_INODE(raw_inode, EXT4_I(inode), xtime ## _extra))     {\
+		(raw_inode)->xtime = cpu_to_le32((inode)->xtime.tv_sec);	\
 		(raw_inode)->xtime ## _extra =					\
 				ext4_encode_extra_time(&(inode)->xtime);	\
 		}								\
+	else	\
+		(raw_inode)->xtime = cpu_to_le32(clamp_t(int32_t, (inode)->xtime.tv_sec, S32_MIN, S32_MAX));	\
 } while (0)
 
 #define EXT4_EINODE_SET_XTIME(xtime, einode, raw_inode)			       \
···
 #define EXT4_MAX_SUPP_REV	EXT4_DYNAMIC_REV
 
 #define EXT4_GOOD_OLD_INODE_SIZE 128
+
+#define EXT4_EXTRA_TIMESTAMP_MAX	(((s64)1 << 34) - 1  + S32_MIN)
+#define EXT4_NON_EXTRA_TIMESTAMP_MAX	S32_MAX
+#define EXT4_TIMESTAMP_MIN		S32_MIN
 
 /*
  * Feature set definitions

fs/ext4/super.c

···
 			       sbi->s_inode_size);
 			goto failed_mount;
 		}
-		if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE)
-			sb->s_time_gran = 1 << (EXT4_EPOCH_BITS - 2);
+		/*
+		 * i_atime_extra is the last extra field available for [acm]times in
+		 * struct ext4_inode. Checking for that field should suffice to ensure
+		 * we have extra space for all three.
+		 */
+		if (sbi->s_inode_size >= offsetof(struct ext4_inode, i_atime_extra) +
+			sizeof(((struct ext4_inode *)0)->i_atime_extra)) {
+			sb->s_time_gran = 1;
+			sb->s_time_max = EXT4_EXTRA_TIMESTAMP_MAX;
+		} else {
+			sb->s_time_gran = NSEC_PER_SEC;
+			sb->s_time_max = EXT4_NON_EXTRA_TIMESTAMP_MAX;
+		}
+
+		sb->s_time_min = EXT4_TIMESTAMP_MIN;
 	}
 
 	sbi->s_desc_size = le16_to_cpu(es->s_desc_size);

fs/f2fs/file.c

···
 		inode->i_uid = attr->ia_uid;
 	if (ia_valid & ATTR_GID)
 		inode->i_gid = attr->ia_gid;
-	if (ia_valid & ATTR_ATIME)
-		inode->i_atime = timespec64_trunc(attr->ia_atime,
-						  inode->i_sb->s_time_gran);
-	if (ia_valid & ATTR_MTIME)
-		inode->i_mtime = timespec64_trunc(attr->ia_mtime,
-						  inode->i_sb->s_time_gran);
-	if (ia_valid & ATTR_CTIME)
-		inode->i_ctime = timespec64_trunc(attr->ia_ctime,
-						  inode->i_sb->s_time_gran);
+	if (ia_valid & ATTR_ATIME) {
+		inode->i_atime = timestamp_truncate(attr->ia_atime,
+						  inode);
+	}
+	if (ia_valid & ATTR_MTIME) {
+		inode->i_mtime = timestamp_truncate(attr->ia_mtime,
+						  inode);
+	}
+	if (ia_valid & ATTR_CTIME) {
+		inode->i_ctime = timestamp_truncate(attr->ia_ctime,
+						  inode);
+	}
 	if (ia_valid & ATTR_MODE) {
 		umode_t mode = attr->ia_mode;
 

fs/fat/inode.c

···
 
 #define KB_IN_SECTORS 2
 
+/* DOS dates from 1980/1/1 through 2107/12/31 */
+#define FAT_DATE_MIN (0<<9 | 1<<5 | 1)
+#define FAT_DATE_MAX (127<<9 | 12<<5 | 31)
+#define FAT_TIME_MAX (23<<11 | 59<<5 | 29)
+
 /*
  * A deserialized copy of the on-disk structure laid out in struct
  * fat_boot_sector.
···
 	int debug;
 	long error;
 	char buf[50];
+	struct timespec64 ts;
 
 	/*
 	 * GFP_KERNEL is ok here, because while we do hold the
···
 	sbi->free_clus_valid = 0;
 	sbi->prev_free = FAT_START_ENT;
 	sb->s_maxbytes = 0xffffffff;
+	fat_time_fat2unix(sbi, &ts, 0, cpu_to_le16(FAT_DATE_MIN), 0);
+	sb->s_time_min = ts.tv_sec;
+
+	fat_time_fat2unix(sbi, &ts, cpu_to_le16(FAT_TIME_MAX),
+			  cpu_to_le16(FAT_DATE_MAX), 0);
+	sb->s_time_max = ts.tv_sec;
 
 	if (!sbi->fat_length && bpb.fat32_length) {
 		struct fat_boot_fsinfo *fsinfo;

fs/freevxfs/vxfs_super.c

···
 
 	sbp->s_op = &vxfs_super_ops;
 	sbp->s_fs_info = infp;
+	sbp->s_time_min = 0;
+	sbp->s_time_max = U32_MAX;
 
 	if (!vxfs_try_sb_magic(sbp, silent, 1,
 			(__force __fs32)cpu_to_le32(VXFS_SUPER_MAGIC))) {

fs/hpfs/hpfs_fn.h

···
  * local time (HPFS) to GMT (Unix)
  */
 
-static inline time64_t local_to_gmt(struct super_block *s, time32_t t)
+static inline time64_t local_to_gmt(struct super_block *s, time64_t t)
 {
 	extern struct timezone sys_tz;
 	return t + sys_tz.tz_minuteswest * 60 + hpfs_sb(s)->sb_timeshift;
···
 static inline time32_t gmt_to_local(struct super_block *s, time64_t t)
 {
 	extern struct timezone sys_tz;
-	t = t - sys_tz.tz_minuteswest * 60 - hpfs_sb(s)->sb_timeshift;
-
-	return clamp_t(time64_t, t, 0, U32_MAX);
+	return t - sys_tz.tz_minuteswest * 60 - hpfs_sb(s)->sb_timeshift;
 }
 
 static inline time32_t local_get_seconds(struct super_block *s)

fs/hpfs/super.c

···
 	s->s_magic = HPFS_SUPER_MAGIC;
 	s->s_op = &hpfs_sops;
 	s->s_d_op = &hpfs_dentry_operations;
+	s->s_time_min =  local_to_gmt(s, 0);
+	s->s_time_max =  local_to_gmt(s, U32_MAX);
 
 	sbi->sb_root = le32_to_cpu(superblock->root);
 	sbi->sb_fs_size = le32_to_cpu(superblock->n_sectors);

fs/inode.c

···
 EXPORT_SYMBOL(timespec64_trunc);
 
 /**
+ * timestamp_truncate - Truncate timespec to a granularity
+ * @t: Timespec
+ * @inode: inode being updated
+ *
+ * Truncate a timespec to the granularity supported by the fs
+ * containing the inode. Always rounds down. gran must
+ * not be 0 nor greater than a second (NSEC_PER_SEC, or 10^9 ns).
+ */
+struct timespec64 timestamp_truncate(struct timespec64 t, struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	unsigned int gran = sb->s_time_gran;
+
+	t.tv_sec = clamp(t.tv_sec, sb->s_time_min, sb->s_time_max);
+	if (unlikely(t.tv_sec == sb->s_time_max || t.tv_sec == sb->s_time_min))
+		t.tv_nsec = 0;
+
+	/* Avoid division in the common cases 1 ns and 1 s. */
+	if (gran == 1)
+		; /* nothing */
+	else if (gran == NSEC_PER_SEC)
+		t.tv_nsec = 0;
+	else if (gran > 1 && gran < NSEC_PER_SEC)
+		t.tv_nsec -= t.tv_nsec % gran;
+	else
+		WARN(1, "invalid file time granularity: %u", gran);
+	return t;
+}
+EXPORT_SYMBOL(timestamp_truncate);
+
+/**
  * current_time - Return FS time
  * @inode: inode.
  *
···
 		return now;
 	}
 
-	return timespec64_trunc(now, inode->i_sb->s_time_gran);
+	return timestamp_truncate(now, inode);
 }
 EXPORT_SYMBOL(current_time);
 

fs/isofs/inode.c

···
 #include "isofs.h"
 #include "zisofs.h"
 
+/* max tz offset is 13 hours */
+#define MAX_TZ_OFFSET (52*15*60)
+
 #define BEQUIET
 
 static int isofs_hashi(const struct dentry *parent, struct qstr *qstr);
···
 	 * size of a file system, which is 8 TB.
 	 */
 	s->s_maxbytes = 0x80000000000LL;
+
+	/* ECMA-119 timestamp from 1900/1/1 with tz offset */
+	s->s_time_min = mktime64(1900, 1, 1, 0, 0, 0) - MAX_TZ_OFFSET;
+	s->s_time_max = mktime64(U8_MAX+1900, 12, 31, 23, 59, 59) + MAX_TZ_OFFSET;
 
 	/* Set this for reference. Its not currently used except on write
 	   which we don't have .. */

fs/jffs2/fs.c

···
 	sb->s_blocksize = PAGE_SIZE;
 	sb->s_blocksize_bits = PAGE_SHIFT;
 	sb->s_magic = JFFS2_SUPER_MAGIC;
+	sb->s_time_min = 0;
+	sb->s_time_max = U32_MAX;
+
 	if (!sb_rdonly(sb))
 		jffs2_start_garbage_collect_thread(c);
 	return 0;

fs/jfs/super.c

···
 
 	sb->s_fs_info = sbi;
 	sb->s_max_links = JFS_LINK_MAX;
+	sb->s_time_min = 0;
+	sb->s_time_max = U32_MAX;
 	sbi->sb = sb;
 	sbi->uid = INVALID_UID;
 	sbi->gid = INVALID_GID;

fs/kernfs/inode.c

···
 static inline void set_inode_attr(struct inode *inode,
 				  struct kernfs_iattrs *attrs)
 {
-	struct super_block *sb = inode->i_sb;
 	inode->i_uid = attrs->ia_uid;
 	inode->i_gid = attrs->ia_gid;
-	inode->i_atime = timespec64_trunc(attrs->ia_atime, sb->s_time_gran);
-	inode->i_mtime = timespec64_trunc(attrs->ia_mtime, sb->s_time_gran);
-	inode->i_ctime = timespec64_trunc(attrs->ia_ctime, sb->s_time_gran);
+	inode->i_atime = timestamp_truncate(attrs->ia_atime, inode);
+	inode->i_mtime = timestamp_truncate(attrs->ia_mtime, inode);
+	inode->i_ctime = timestamp_truncate(attrs->ia_ctime, inode);
 }
 
 static void kernfs_refresh_inode(struct kernfs_node *kn, struct inode *inode)

fs/minix/inode.c

···
 
 	/* set up enough so that it can read an inode */
 	s->s_op = &minix_sops;
+	s->s_time_min = 0;
+	s->s_time_max = U32_MAX;
 	root_inode = minix_iget(s, MINIX_ROOT_INO);
 	if (IS_ERR(root_inode)) {
 		ret = PTR_ERR(root_inode);

fs/namespace.c

···
 	unlock_mount_hash();
 }
 
+static void mnt_warn_timestamp_expiry(struct path *mountpoint, struct vfsmount *mnt)
+{
+	struct super_block *sb = mnt->mnt_sb;
+
+	if (!__mnt_is_readonly(mnt) &&
+	   (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);
+		struct tm tm;
+
+		time64_to_tm(sb->s_time_max, 0, &tm);
+
+		pr_warn("Mounted %s file system at %s supports timestamps until %04ld (0x%llx)\n",
+			sb->s_type->name, mntpath,
+			tm.tm_year+1900, (unsigned long long)sb->s_time_max);
+
+		free_page((unsigned long)buf);
+	}
+}
+
 /*
  * Handle reconfiguration of the mountpoint only without alteration of the
  * superblock it refers to.  This is triggered by specifying MS_REMOUNT|MS_BIND
···
 	if (ret == 0)
 		set_mount_attributes(mnt, mnt_flags);
 	up_write(&sb->s_umount);
+
+	mnt_warn_timestamp_expiry(path, &mnt->mnt);
+
 	return ret;
 }
 
···
 		}
 		up_write(&sb->s_umount);
 	}
+
+	mnt_warn_timestamp_expiry(path, &mnt->mnt);
+
 	put_fs_context(fc);
 	return err;
 }
···
 		return PTR_ERR(mnt);
 
 	error = do_add_mount(real_mount(mnt), mountpoint, mnt_flags);
-	if (error < 0)
+	if (error < 0) {
 		mntput(mnt);
+		return error;
+	}
+
+	mnt_warn_timestamp_expiry(mountpoint, mnt);
+
 	return error;
 }
 

fs/nfs/super.c

···
 		sb->s_flags |= SB_POSIXACL;
 		sb->s_time_gran = 1;
 		sb->s_export_op = &nfs_export_ops;
+	} else
+		sb->s_time_gran = 1000;
+
+	if (server->nfs_client->rpc_ops->version != 4) {
+		sb->s_time_min = 0;
+		sb->s_time_max = U32_MAX;
+	} else {
+		sb->s_time_min = S64_MIN;
+		sb->s_time_max = S64_MAX;
 	}
 
  	nfs_initialise_sb(sb);
···
 	sb->s_maxbytes = old_sb->s_maxbytes;
 	sb->s_xattr = old_sb->s_xattr;
 	sb->s_op = old_sb->s_op;
-	sb->s_time_gran = 1;
 	sb->s_export_op = old_sb->s_export_op;
 
 	if (server->nfs_client->rpc_ops->version != 2) {
···
 		 * so ourselves when necessary.
 		 */
 		sb->s_flags |= SB_POSIXACL;
+		sb->s_time_gran = 1;
+	} else
+		sb->s_time_gran = 1000;
+
+	if (server->nfs_client->rpc_ops->version != 4) {
+		sb->s_time_min = 0;
+		sb->s_time_max = U32_MAX;
+	} else {
+		sb->s_time_min = S64_MIN;
+		sb->s_time_max = S64_MAX;
 	}
 
  	nfs_initialise_sb(sb);

fs/ntfs/inode.c

···
 			ia_valid |= ATTR_MTIME | ATTR_CTIME;
 		}
 	}
-	if (ia_valid & ATTR_ATIME)
-		vi->i_atime = timespec64_trunc(attr->ia_atime,
-					       vi->i_sb->s_time_gran);
-	if (ia_valid & ATTR_MTIME)
-		vi->i_mtime = timespec64_trunc(attr->ia_mtime,
-					       vi->i_sb->s_time_gran);
-	if (ia_valid & ATTR_CTIME)
-		vi->i_ctime = timespec64_trunc(attr->ia_ctime,
-					       vi->i_sb->s_time_gran);
+	if (ia_valid & ATTR_ATIME) {
+		vi->i_atime = timestamp_truncate(attr->ia_atime,
+					       vi);
+	}
+	if (ia_valid & ATTR_MTIME) {
+		vi->i_mtime = timestamp_truncate(attr->ia_mtime,
+					       vi);
+	}
+	if (ia_valid & ATTR_CTIME) {
+		vi->i_ctime = timestamp_truncate(attr->ia_ctime,
+					       vi);
+	}
 	mark_inode_dirty(vi);
 out:
 	return err;

fs/omfs/inode.c

···
 
 	sb->s_maxbytes = 0xffffffff;
 
+	sb->s_time_gran = NSEC_PER_MSEC;
+	sb->s_time_min = 0;
+	sb->s_time_max = U64_MAX / MSEC_PER_SEC;
+
 	sb_set_blocksize(sb, 0x200);
 
 	bh = sb_bread(sb, 0);

fs/pstore/ram.c

···
 	if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu-%c\n%n",
 		   (time64_t *)&time->tv_sec, &time->tv_nsec, &data_type,
 		   &header_length) == 3) {
+		time->tv_nsec *= 1000;
 		if (data_type == 'C')
 			*compressed = true;
 		else
···
 	} else if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu\n%n",
 			  (time64_t *)&time->tv_sec, &time->tv_nsec,
 			  &header_length) == 2) {
+		time->tv_nsec *= 1000;
 		*compressed = false;
 	} else {
 		time->tv_sec = 0;

fs/qnx4/inode.c

···
 	s->s_op = &qnx4_sops;
 	s->s_magic = QNX4_SUPER_MAGIC;
 	s->s_flags |= SB_RDONLY;	/* Yup, read-only yet */
+	s->s_time_min = 0;
+	s->s_time_max = U32_MAX;
 
 	/* Check the superblock signature. Since the qnx4 code is
 	   dangerous, we should leave as quickly as possible

fs/qnx6/inode.c

···
 	s->s_op = &qnx6_sops;
 	s->s_magic = QNX6_SUPER_MAGIC;
 	s->s_flags |= SB_RDONLY;        /* Yup, read-only yet */
+	s->s_time_min = 0;
+	s->s_time_max = U32_MAX;
 
 	/* ease the later tree level calculations */
 	sbi = QNX6_SB(s);

fs/reiserfs/super.c

···
 		goto error_unlocked;
 	}
 
+	s->s_time_min = 0;
+	s->s_time_max = U32_MAX;
+
 	rs = SB_DISK_SUPER_BLOCK(s);
 	/*
 	 * Let's do basic sanity check to verify that underlying device is not

fs/romfs/super.c

···
 	sb->s_maxbytes = 0xFFFFFFFF;
 	sb->s_magic = ROMFS_MAGIC;
 	sb->s_flags |= SB_RDONLY | SB_NOATIME;
+	sb->s_time_min = 0;
+	sb->s_time_max = 0;
 	sb->s_op = &romfs_super_ops;
 
 #ifdef CONFIG_ROMFS_ON_MTD

fs/squashfs/super.c

···
 		(u64) le64_to_cpu(sblk->id_table_start));
 
 	sb->s_maxbytes = MAX_LFS_FILESIZE;
+	sb->s_time_min = 0;
+	sb->s_time_max = U32_MAX;
 	sb->s_flags |= SB_RDONLY;
 	sb->s_op = &squashfs_super_ops;
 

fs/super.c

···
 	s->s_maxbytes = MAX_NON_LFS;
 	s->s_op = &default_op;
 	s->s_time_gran = 1000000000;
+	s->s_time_min = TIME64_MIN;
+	s->s_time_max = TIME64_MAX;
 	s->cleancache_poolid = CLEANCACHE_NO_POOL;
 
 	s->s_shrink.seeks = DEFAULT_SEEKS;

fs/sysv/super.c

···
 	sbi->s_block_base = 0;
 	mutex_init(&sbi->s_lock);
 	sb->s_fs_info = sbi;
-
+	sb->s_time_min = 0;
+	sb->s_time_max = U32_MAX;
 	sb_set_blocksize(sb, BLOCK_SIZE);
 
 	for (i = 0; i < ARRAY_SIZE(flavours) && !size; i++) {
···
 	sbi->s_type = FSTYPE_V7;
 	mutex_init(&sbi->s_lock);
 	sb->s_fs_info = sbi;
+	sb->s_time_min = 0;
+	sb->s_time_max = U32_MAX;
 	
 	sb_set_blocksize(sb, 512);
 

fs/ubifs/file.c

···
 		inode->i_uid = attr->ia_uid;
 	if (attr->ia_valid & ATTR_GID)
 		inode->i_gid = attr->ia_gid;
-	if (attr->ia_valid & ATTR_ATIME)
-		inode->i_atime = timespec64_trunc(attr->ia_atime,
-						  inode->i_sb->s_time_gran);
-	if (attr->ia_valid & ATTR_MTIME)
-		inode->i_mtime = timespec64_trunc(attr->ia_mtime,
-						  inode->i_sb->s_time_gran);
-	if (attr->ia_valid & ATTR_CTIME)
-		inode->i_ctime = timespec64_trunc(attr->ia_ctime,
-						  inode->i_sb->s_time_gran);
+	if (attr->ia_valid & ATTR_ATIME) {
+		inode->i_atime = timestamp_truncate(attr->ia_atime,
+						  inode);
+	}
+	if (attr->ia_valid & ATTR_MTIME) {
+		inode->i_mtime = timestamp_truncate(attr->ia_mtime,
+						  inode);
+	}
+	if (attr->ia_valid & ATTR_CTIME) {
+		inode->i_ctime = timestamp_truncate(attr->ia_ctime,
+						  inode);
+	}
 	if (attr->ia_valid & ATTR_MODE) {
 		umode_t mode = attr->ia_mode;
 

fs/ufs/super.c

···
 
 	sb->s_maxbytes = MAX_LFS_FILESIZE;
 
+	sb->s_time_gran = NSEC_PER_SEC;
+	sb->s_time_min = S32_MIN;
+	sb->s_time_max = S32_MAX;
+
 	switch (sbi->s_mount_opt & UFS_MOUNT_UFSTYPE) {
 	case UFS_MOUNT_UFSTYPE_44BSD:
 		UFSD("ufstype=44bsd\n");
···
 		uspi->s_fshift = 9;
 		uspi->s_sbsize = super_block_size = 1536;
 		uspi->s_sbbase =  0;
+		sb->s_time_gran = 1;
+		sb->s_time_min = S64_MIN;
+		sb->s_time_max = S64_MAX;
 		flags |= UFS_TYPE_UFS2 | UFS_DE_44BSD | UFS_UID_44BSD | UFS_ST_44BSD | UFS_CG_44BSD;
 		break;
 		

fs/utimes.c

···
 		if (times[0].tv_nsec == UTIME_OMIT)
 			newattrs.ia_valid &= ~ATTR_ATIME;
 		else if (times[0].tv_nsec != UTIME_NOW) {
-			newattrs.ia_atime.tv_sec = times[0].tv_sec;
-			newattrs.ia_atime.tv_nsec = times[0].tv_nsec;
+			newattrs.ia_atime = timestamp_truncate(times[0], inode);
 			newattrs.ia_valid |= ATTR_ATIME_SET;
 		}
 
 		if (times[1].tv_nsec == UTIME_OMIT)
 			newattrs.ia_valid &= ~ATTR_MTIME;
 		else if (times[1].tv_nsec != UTIME_NOW) {
-			newattrs.ia_mtime.tv_sec = times[1].tv_sec;
-			newattrs.ia_mtime.tv_nsec = times[1].tv_nsec;
+			newattrs.ia_mtime = timestamp_truncate(times[1], inode);
 			newattrs.ia_valid |= ATTR_MTIME_SET;
 		}
 		/*

fs/xfs/xfs_super.c

···
 	sb->s_maxbytes = xfs_max_file_offset(sb->s_blocksize_bits);
 	sb->s_max_links = XFS_MAXLINK;
 	sb->s_time_gran = 1;
+	sb->s_time_min = S32_MIN;
+	sb->s_time_max = S32_MAX;
 	sb->s_iflags |= SB_I_CGROUPWB;
 
 	set_posix_acl_flag(sb);

include/linux/fs.h

···
 	void			*i_private; /* fs or device private pointer */
 } __randomize_layout;
 
+struct timespec64 timestamp_truncate(struct timespec64 t, struct inode *inode);
+
 static inline unsigned int i_blocksize(const struct inode *node)
 {
 	return (1 << node->i_blkbits);
···
 
 	/* Granularity of c/m/atime in ns (cannot be worse than a second) */
 	u32			s_time_gran;
+	/* Time limits for c/m/atime in seconds */
+	time64_t		   s_time_min;
+	time64_t		   s_time_max;
 #ifdef CONFIG_FSNOTIFY
 	__u32			s_fsnotify_mask;
 	struct fsnotify_mark_connector __rcu	*s_fsnotify_marks;

include/linux/time64.h

···
 
 /* Located here for timespec[64]_valid_strict */
 #define TIME64_MAX			((s64)~((u64)1 << 63))
+#define TIME64_MIN			(-TIME64_MAX - 1)
+
 #define KTIME_MAX			((s64)~((u64)1 << 63))
 #define KTIME_SEC_MAX			(KTIME_MAX / NSEC_PER_SEC)