Re: fsync, ext2 on Linux - Mailing list pgsql-hackers

From Andrew Dunstan
Subject Re: fsync, ext2 on Linux
Date
Msg-id 4185054C.9050500@dunslane.net
Whole thread Raw
In response to Re: fsync, ext2 on Linux  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers

Tom Lane wrote:

>Heikki Linnakangas <hlinnaka@iki.fi> writes:
>  
>
>>The Linux [ext2] 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."
>>    
>>
>
>This seems so broken as to defy belief.  A process creating a file
>doesn't normally *have* a file descriptor for the parent directory,
>and I don't think the concept of an FD for a directory is even
>portable (opendir() certainly doesn't return an FD).  One might also
>ask if we are expected to fsync everything up to the root in order
>to be sure that the file remains accessible, and how exactly we should
>do that on directories we don't have write access for.
>  
>

The notes say this:
      When  an  ext2  file  system is mounted with the sync option, 
directory      entries are also implicitly synced by fsync.

cheers

andrew




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