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ext4: drop legacy pre-1970 encoding workaround

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Originally, support for expanded timestamps had a bug in that pre-1970
times were erroneously encoded as being in the the 24th century.  This
was fixed in commit a4dad1ae24 ("ext4: Fix handling of extended
tv_sec") which landed in 4.4.  Starting with 4.4, pre-1970 timestamps
were correctly encoded, but for backwards compatibility those
incorrectly encoded timestamps were mapped back to the pre-1970 dates.

Given that backwards compatibility workaround has been around for 4
years, and given that running e2fsck from e2fsprogs 1.43.2 and later
will offer to fix these timestamps (which has been released for 3
years), it's past time to drop the legacy workaround from the kernel.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2019-08-12 13:44:49 -04:00
parent bb5835edcd
commit cd2d99229d
1 changed files with 1 additions and 14 deletions
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15
fs/ext4/ext4.h
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@ -828,21 +828,8 @@ static inline __le32 ext4_encode_extra_time(struct timespec64 *time)
static inline void ext4_decode_extra_time(struct timespec64 *time,
__le32 extra)
{
if (unlikely(extra & cpu_to_le32(EXT4_EPOCH_MASK))) {
#if 1
/* Handle legacy encoding of pre-1970 dates with epoch
* bits 1,1. (This backwards compatibility may be removed
* at the discretion of the ext4 developers.)
*/
u64 extra_bits = le32_to_cpu(extra) & EXT4_EPOCH_MASK;
if (extra_bits == 3 && ((time->tv_sec) & 0x80000000) != 0)
extra_bits = 0;
time->tv_sec += extra_bits << 32;
#else
if (unlikely(extra & cpu_to_le32(EXT4_EPOCH_MASK)))
time->tv_sec += (u64)(le32_to_cpu(extra) & EXT4_EPOCH_MASK) << 32;
#endif
}
time->tv_nsec = (le32_to_cpu(extra) & EXT4_NSEC_MASK) >> EXT4_EPOCH_BITS;
}