* Garbage returned in nanosecond component of timestamps
@ 2010-11-20 6:22 Jordan Russell
2010-11-20 7:53 ` Eric Sandeen
2010-11-22 17:45 ` [PATCH] ext4: zero out nanosecond timestamps for small inodes Eric Sandeen
0 siblings, 2 replies; 4+ messages in thread
From: Jordan Russell @ 2010-11-20 6:22 UTC (permalink / raw)
To: linux-ext4
[Fedora 14 with vendor kernel 2.6.35.6-48.fc14.i686.PAE]
When nanosecond timestamp resolution isn't supported on an ext4
partition (inode size = 128), stat() appears to be returning
uninitialized garbage in the nanosecond component of timestamps.
See the following tests.
Expected: All timestamps should end with '.0000000000'.
Actual: '.0026721629' popping up on a different file each time.
> # tune2fs -l /dev/md0 | fgrep 'Inode size'
> Inode size: 128
> # echo 3 >/proc/sys/vm/drop_caches
> # find / -xdev -type f -printf '%t - %p\n' | fgrep -v '.0000000000'
> Wed Nov 4 16:53:20.0026721629 2009 - /boot/oldconfigs/config-2.6.27.38-170.2.113.fc10.i686.PAE
> # echo 3 >/proc/sys/vm/drop_caches
> # find / -xdev -type f -printf '%t - %p\n' | fgrep -v '.0000000000'
> Thu Nov 8 20:38:30.0026721629 2007 - /boot/oldconfigs/config-2.6.23.1-49.fc8PAE
> # echo 3 >/proc/sys/vm/drop_caches
> # find / -xdev -type f -printf '%t - %p\n' | fgrep -v '.0000000000'
> Thu Aug 12 17:44:51.0026721629 2010 - /lib/firmware/emi26/bitstream.fw
> # echo 3 >/proc/sys/vm/drop_caches
> # find / -xdev -type f -printf '%t - %p\n' | fgrep -v '.0000000000'
> Thu Aug 12 17:44:51.0026721629 2010 - /lib/firmware/slicoss/gbdownload.sys
> # echo 3 >/proc/sys/vm/drop_caches
> # find / -xdev -type f -printf '%t - %p\n' | fgrep -v '.0000000000'
> Fri Nov 5 01:16:32.0026721629 2010 - /boot/grub/e2fs_stage1_5
Shouldn't EXT4_INODE_GET_XTIME zero out tv_nsec when EXT4_FITS_IN_INODE
evaluates to false...?
> #define EXT4_INODE_GET_XTIME(xtime, inode, raw_inode) \
> do { \
> (inode)->xtime.tv_sec = (signed)le32_to_cpu((raw_inode)->xtime); \
> if (EXT4_FITS_IN_INODE(raw_inode, EXT4_I(inode), xtime ## _extra)) \
> ext4_decode_extra_time(&(inode)->xtime, \
> raw_inode->xtime ## _extra); \
> } while (0)
--
Jordan Russell
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Garbage returned in nanosecond component of timestamps
2010-11-20 6:22 Garbage returned in nanosecond component of timestamps Jordan Russell
@ 2010-11-20 7:53 ` Eric Sandeen
2010-11-22 17:45 ` [PATCH] ext4: zero out nanosecond timestamps for small inodes Eric Sandeen
1 sibling, 0 replies; 4+ messages in thread
From: Eric Sandeen @ 2010-11-20 7:53 UTC (permalink / raw)
To: Jordan Russell; +Cc: linux-ext4
On 11/20/10 12:22 AM, Jordan Russell wrote:
> [Fedora 14 with vendor kernel 2.6.35.6-48.fc14.i686.PAE]
>
> When nanosecond timestamp resolution isn't supported on an ext4
> partition (inode size = 128), stat() appears to be returning
> uninitialized garbage in the nanosecond component of timestamps.
>
> See the following tests.
> Expected: All timestamps should end with '.0000000000'.
> Actual: '.0026721629' popping up on a different file each time.
>
>> # tune2fs -l /dev/md0 | fgrep 'Inode size'
>> Inode size: 128
>> # echo 3 >/proc/sys/vm/drop_caches
>> # find / -xdev -type f -printf '%t - %p\n' | fgrep -v '.0000000000'
>> Wed Nov 4 16:53:20.0026721629 2009 - /boot/oldconfigs/config-2.6.27.38-170.2.113.fc10.i686.PAE
>> # echo 3 >/proc/sys/vm/drop_caches
>> # find / -xdev -type f -printf '%t - %p\n' | fgrep -v '.0000000000'
>> Thu Nov 8 20:38:30.0026721629 2007 - /boot/oldconfigs/config-2.6.23.1-49.fc8PAE
>> # echo 3 >/proc/sys/vm/drop_caches
>> # find / -xdev -type f -printf '%t - %p\n' | fgrep -v '.0000000000'
>> Thu Aug 12 17:44:51.0026721629 2010 - /lib/firmware/emi26/bitstream.fw
>> # echo 3 >/proc/sys/vm/drop_caches
>> # find / -xdev -type f -printf '%t - %p\n' | fgrep -v '.0000000000'
>> Thu Aug 12 17:44:51.0026721629 2010 - /lib/firmware/slicoss/gbdownload.sys
>> # echo 3 >/proc/sys/vm/drop_caches
>> # find / -xdev -type f -printf '%t - %p\n' | fgrep -v '.0000000000'
>> Fri Nov 5 01:16:32.0026721629 2010 - /boot/grub/e2fs_stage1_5
>
>
> Shouldn't EXT4_INODE_GET_XTIME zero out tv_nsec when EXT4_FITS_IN_INODE
> evaluates to false...?
Yep I think so, good catch...
-Eric
>> #define EXT4_INODE_GET_XTIME(xtime, inode, raw_inode) \
>> do { \
>> (inode)->xtime.tv_sec = (signed)le32_to_cpu((raw_inode)->xtime); \
>> if (EXT4_FITS_IN_INODE(raw_inode, EXT4_I(inode), xtime ## _extra)) \
>> ext4_decode_extra_time(&(inode)->xtime, \
>> raw_inode->xtime ## _extra); \
>> } while (0)
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] ext4: zero out nanosecond timestamps for small inodes
2010-11-20 6:22 Garbage returned in nanosecond component of timestamps Jordan Russell
2010-11-20 7:53 ` Eric Sandeen
@ 2010-11-22 17:45 ` Eric Sandeen
2010-12-20 3:11 ` Ted Ts'o
1 sibling, 1 reply; 4+ messages in thread
From: Eric Sandeen @ 2010-11-22 17:45 UTC (permalink / raw)
To: Jordan Russell; +Cc: linux-ext4
As reported by Jordan Russell:
When nanosecond timestamp resolution isn't supported on an ext4
partition (inode size = 128), stat() appears to be returning
uninitialized garbage in the nanosecond component of timestamps.
EXT4_INODE_GET_XTIME should zero out tv_nsec when EXT4_FITS_IN_INODE
evaluates to false.
Reported-by: Jordan Russell <jr-list-2010@quo.to>
Signed-of-by: Eric Sandeen <sandeen@redhat.com>
---
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 6a5edea..1541e3e 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -709,6 +709,8 @@ do { \
if (EXT4_FITS_IN_INODE(raw_inode, EXT4_I(inode), xtime ## _extra)) \
ext4_decode_extra_time(&(inode)->xtime, \
raw_inode->xtime ## _extra); \
+ else \
+ (inode)->xtime.tv_nsec = 0; \
} while (0)
#define EXT4_EINODE_GET_XTIME(xtime, einode, raw_inode) \
@@ -719,6 +721,8 @@ do { \
if (EXT4_FITS_IN_INODE(raw_inode, einode, xtime ## _extra)) \
ext4_decode_extra_time(&(einode)->xtime, \
raw_inode->xtime ## _extra); \
+ else \
+ (einode)->xtime.tv_nsec = 0; \
} while (0)
#define i_disk_version osd1.linux1.l_i_version
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] ext4: zero out nanosecond timestamps for small inodes
2010-11-22 17:45 ` [PATCH] ext4: zero out nanosecond timestamps for small inodes Eric Sandeen
@ 2010-12-20 3:11 ` Ted Ts'o
0 siblings, 0 replies; 4+ messages in thread
From: Ted Ts'o @ 2010-12-20 3:11 UTC (permalink / raw)
To: Eric Sandeen; +Cc: Jordan Russell, linux-ext4
On Mon, Nov 22, 2010 at 11:45:48AM -0600, Eric Sandeen wrote:
> As reported by Jordan Russell:
>
> When nanosecond timestamp resolution isn't supported on an ext4
> partition (inode size = 128), stat() appears to be returning
> uninitialized garbage in the nanosecond component of timestamps.
>
> EXT4_INODE_GET_XTIME should zero out tv_nsec when EXT4_FITS_IN_INODE
> evaluates to false.
>
> Reported-by: Jordan Russell <jr-list-2010@quo.to>
> Signed-of-by: Eric Sandeen <sandeen@redhat.com>
Thanks, added to the ext4 patch queue.
- Ted
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2010-12-20 3:11 UTC | newest]
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2010-11-20 6:22 Garbage returned in nanosecond component of timestamps Jordan Russell
2010-11-20 7:53 ` Eric Sandeen
2010-11-22 17:45 ` [PATCH] ext4: zero out nanosecond timestamps for small inodes Eric Sandeen
2010-12-20 3:11 ` Ted Ts'o
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