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| author | Markus Rechberger <Markus.Rechberger@amd.com> | 2007-05-08 00:23:39 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-08 11:14:58 -0700 |
| commit | 4d7bf11d649c72621ca31b8ea12b9c94af380e63 (patch) | |
| tree | c4a3c11cf6d13210ed344de0ae091d3f7523c689 /fs/ext2 | |
| parent | 8948e11f450e6189a79e47d6051c3d5a0b98e3f3 (diff) | |
| download | linux-4d7bf11d649c72621ca31b8ea12b9c94af380e63.tar.bz2 | |
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>
Diffstat (limited to 'fs/ext2')
| -rw-r--r-- | fs/ext2/inode.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index dd4e14c221e0..9fa1bd65a028 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c @@ -1079,9 +1079,9 @@ void ext2_read_inode (struct inode * inode) } inode->i_nlink = le16_to_cpu(raw_inode->i_links_count); inode->i_size = le32_to_cpu(raw_inode->i_size); - inode->i_atime.tv_sec = le32_to_cpu(raw_inode->i_atime); - inode->i_ctime.tv_sec = le32_to_cpu(raw_inode->i_ctime); - inode->i_mtime.tv_sec = le32_to_cpu(raw_inode->i_mtime); + inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime); + inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime); + inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime); inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0; ei->i_dtime = le32_to_cpu(raw_inode->i_dtime); /* We now have enough fields to check if the inode was active or not. |