android_kernel_xiaomi_sm8350/fs/ext3
Markus Rechberger 4d7bf11d64 ext2/3/4: fix file date underflow on ext2 3 filesystems on 64 bit systems
Taken from http://bugzilla.kernel.org/show_bug.cgi?id=5079

signed long ranges from -2.147.483.648 to 2.147.483.647 on x86 32bit

10000011110110100100111110111101 .. -2,082,844,739
10000011110110100100111110111101 ..  2,212,122,557 <- this currently gets
stored on the disk but when converting it to a 64bit signed long value it loses
its sign and becomes positive.

Cc: Andreas Dilger <adilger@dilger.ca>
Cc: <linux-ext4@vger.kernel.org>

Andreas says:

This patch is now treating timestamps with the high bit set as negative
times (before Jan 1, 1970).  This means we lose 1/2 of the possible range
of timestamps (lopping off 68 years before unix timestamp overflow -
now only 30 years away :-) to handle the extremely rare case of setting
timestamps into the distant past.

If we are only interested in fixing the underflow case, we could just
limit the values to 0 instead of storing negative values.  At worst this
will skew the timestamp by a few hours for timezones in the far east
(files would still show Jan 1, 1970 in "ls -l" output).

That said, it seems 32-bit systems (mine at least) allow files to be set
into the past (01/01/1907 works fine) so it seems this patch is bringing
the x86_64 behaviour into sync with other kernels.

On the plus side, we have a patch that is ready to add nanosecond timestamps
to ext3 and as an added bonus adds 2 high bits to the on-disk timestamp so
this extends the maximum date to 2242.

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:14:58 -07:00
..
acl.c
acl.h
balloc.c [PATCH] ext[234]: update documentation 2007-02-20 17:10:14 -08:00
bitmap.c
dir.c [PATCH] ext3: change uses of f_{dentry, vfsmnt} to use f_path 2006-12-08 08:28:41 -08:00
ext3_jbd.c [PATCH] ext3: uninline large functions 2006-12-07 08:39:35 -08:00
file.c [PATCH] mark struct inode_operations const 1 2007-02-12 09:48:46 -08:00
fsync.c
hash.c [PATCH] remove many unneeded #includes of sched.h 2007-02-14 08:09:54 -08:00
ialloc.c
inode.c ext2/3/4: fix file date underflow on ext2 3 filesystems on 64 bit systems 2007-05-08 11:14:58 -07:00
ioctl.c [PATCH] ext3: change uses of f_{dentry, vfsmnt} to use f_path 2006-12-08 08:28:41 -08:00
Makefile [PATCH] ext3: uninline large functions 2006-12-07 08:39:35 -08:00
namei.c [PATCH] mark struct inode_operations const 1 2007-02-12 09:48:46 -08:00
namei.h
resize.c [PATCH] remove many unneeded #includes of sched.h 2007-02-14 08:09:54 -08:00
super.c slab allocators: Remove SLAB_DEBUG_INITIAL flag 2007-05-07 12:12:57 -07:00
symlink.c [PATCH] mark struct inode_operations const 1 2007-02-12 09:48:46 -08:00
xattr_security.c
xattr_trusted.c
xattr_user.c
xattr.c [PATCH] "ext[34]: EA block reference count racing fix" performance fix 2007-03-23 11:01:22 -07:00
xattr.h