ext4 has different overflow limits for max filesystem timestamps based on the extra bytes available.
The timestamp limits are calculated according to the encoding table in a4dad1ae24f85i(ext4: Fix handling of extended tv_sec):
* extra msb of adjust for signed * epoch 32-bit 32-bit tv_sec to * bits time decoded 64-bit tv_sec 64-bit tv_sec valid time range * 0 0 1 -0x80000000..-0x00000001 0x000000000 1901-12-13..1969-12-31 * 0 0 0 0x000000000..0x07fffffff 0x000000000 1970-01-01..2038-01-19 * 0 1 1 0x080000000..0x0ffffffff 0x100000000 2038-01-19..2106-02-07 * 0 1 0 0x100000000..0x17fffffff 0x100000000 2106-02-07..2174-02-25 * 1 0 1 0x180000000..0x1ffffffff 0x200000000 2174-02-25..2242-03-16 * 1 0 0 0x200000000..0x27fffffff 0x200000000 2242-03-16..2310-04-04 * 1 1 1 0x280000000..0x2ffffffff 0x300000000 2310-04-04..2378-04-22 * 1 1 0 0x300000000..0x37fffffff 0x300000000 2378-04-22..2446-05-10
Note that the time limits are not correct for deletion times.
Added a warn when an inode cannot be extended to incorporate an extended timestamp.
Signed-off-by: Deepa Dinamani deepa.kernel@gmail.com Reviewed-by: Andreas Dilger adilger@dilger.ca Cc: tytso@mit.edu Cc: adilger.kernel@dilger.ca Cc: linux-ext4@vger.kernel.org --- fs/ext4/ext4.h | 10 +++++++++- fs/ext4/super.c | 17 +++++++++++++++-- 2 files changed, 24 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 9c7f4036021b..ae5d0c86aba2 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -832,11 +832,15 @@ static inline void ext4_decode_extra_time(struct timespec64 *time,
#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)); \ + ext4_warning_inode(inode, "inode does not support timestamps beyond 2038"); \ + } \ } while (0)
#define EXT4_EINODE_SET_XTIME(xtime, einode, raw_inode) \ @@ -1643,6 +1647,10 @@ static inline bool ext4_verity_in_progress(struct inode *inode)
#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 */ diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 27cd622676e7..3db5f17228b7 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -4039,8 +4039,21 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) 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);