Re: Wrong DIF guard tag on ext2 write

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Tue, 2010-06-01 at 09:50 -0400, Martin K. Petersen wrote:
> >>>>> "James" == James Bottomley <James.Bottomley@xxxxxxx> writes:
> 
> James> Would it be too much work in the fs to mark the page dirty before
> James> you begin altering it (and again after you finish, just in case
> James> some cleaner noticed and initiated a write)?  Or some other flag
> James> that indicates page under modification?  All the process
> James> controlling the writeout (which is pretty high up in the stack)
> James> needs to know is if we triggered the check error by altering the
> James> page while it was in flight.
> 
> James> I agree that a block based retry would close all the holes ... it
> James> just doesn't look elegant to me that the fs will already be
> James> repeating the I/O if it changed the page and so will block.
> 
> I experimented with this approach a while back.  However, I quickly got
> into a situation where frequently updated blocks never made it to disk
> because the page was constantly being updated.  And all writes failed
> with a guard tag error.

But that's unfixable with a retry based system as well if the page is
changing so fast that the guard is always wrong by the time we get to
the array.  The only way to fix this is either to copy or freeze the
page.

James



--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [Samba]     [Device Mapper]     [CEPH Development]
  Powered by Linux