* Mystery solved? files not written for days...
@ 2009-03-30 22:01 Eric Sandeen
2009-03-30 22:30 ` Felix Blyakher
0 siblings, 1 reply; 2+ messages in thread
From: Eric Sandeen @ 2009-03-30 22:01 UTC (permalink / raw)
To: xfs mailing list
On LKML:
[PATCH] writeback: guard against jiffies wraparound on
inode->dirtied_when checks
When a file is continually dirtied, the check in sync_sb_inodes:
/* Was this inode dirtied after sync_sb_inodes was called? */
if (time_after(inode->dirtied_when, start))
break;
may have large windows where this trips on the first
(continually-dirtied) inode on the list when the time_after check has
wrapped, causing the nothing to be written out for that superblock,
potentially for days.
Could this be the reason for those various "hey, my file disappeared
after a crash and I hadn't written to it for *days*" reports we got now
and then, leaving us all scratching our heads?
-Eric
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^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: Mystery solved? files not written for days...
2009-03-30 22:01 Mystery solved? files not written for days Eric Sandeen
@ 2009-03-30 22:30 ` Felix Blyakher
0 siblings, 0 replies; 2+ messages in thread
From: Felix Blyakher @ 2009-03-30 22:30 UTC (permalink / raw)
To: Eric Sandeen; +Cc: xfs mailing list
On Mar 30, 2009, at 5:01 PM, Eric Sandeen wrote:
> On LKML:
>
> [PATCH] writeback: guard against jiffies wraparound on
> inode->dirtied_when checks
The "jiffies wraparound" sounds very familiar, but I
thought it's been fixed ages ago.
> When a file is continually dirtied, the check in sync_sb_inodes:
>
> /* Was this inode dirtied after sync_sb_inodes was called? */
> if (time_after(inode->dirtied_when, start))
> break;
>
> may have large windows where this trips on the first
> (continually-dirtied) inode on the list when the time_after check has
> wrapped, causing the nothing to be written out for that superblock,
> potentially for days.
>
> Could this be the reason for those various "hey, my file disappeared
> after a crash and I hadn't written to it for *days*" reports we got
> now
> and then, leaving us all scratching our heads?
The "jiffies wraparound" could definitely cause this.
Felix
>
>
> -Eric
>
> _______________________________________________
> xfs mailing list
> xfs@oss.sgi.com
> http://oss.sgi.com/mailman/listinfo/xfs
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xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
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2009-03-30 22:01 Mystery solved? files not written for days Eric Sandeen
2009-03-30 22:30 ` Felix Blyakher
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