Re: fsync, ext2 on Linux

Heikki Linnakangas wrote:
> The Linux fsync man page says:
> 
> "It does not necessarily ensure that the entry in the directory 
> containing the file has also reached disk. For that an explicit fsync on 
> the file descriptor of the directory is also needed."
> 
> AFAIK, we don't care about it at the moment. The actual behaviour 
> depends on the filesystem, reiserfs and other journaling filesystems 
> probably don't need the explicit fsync on the parent directory, but at 
> least ext2 does.
> 
> I've experimented with a user-mode-linux installation, crashing it at 
> specific points. It seems that on ext2, it's possible to get the 
> database in non-consistent state.

Have you experimented with mounting the filesystem with the dirsync 
option ('-o dirsync') or marking the log directory as synchronous with 
'chattr +D'?  (no, it's not a real fix, just another data point..)

-O