[lkml]   [2001]   [Apr]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] SMP race in ext2 - metadata corruption.
On Thu, Apr 26, 2001 at 11:45:47AM -0400, Alexander Viro wrote:
> Ext2 does getblk+wait_on_buffer for new metadata blocks before
> filling them with zeroes. While that is enough for single-processor,
> on SMP we have the following race:
> getblk gives us unlocked, non-uptodate bh
> wait_on_buffer() does nothing
> read from device locks it and starts IO
> we zero it out.
> on-disk data overwrites our zeroes.
> we mark it dirty
> bdflush writes the old data (_not_ zeroes) back to disk.
> Result: crap in metadata block. Proposed fix: lock_buffer()/unlock_buffer()
> around memset()/mark_buffer_uptodate() instead of wait_on_buffer() before
> them.
> Patch against 2.4.4-pre7 follows. Please, apply.

correct. I bet other fs are affected as well btw.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 12:52    [W:0.116 / U:2.004 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site