umount and data is lost?

[Diego]

On Saturday, November 05, 2011 11:22:04 PM shimi wrote:
> > man 2 sync says:
> BUGS
>        According  to  the standard specification (e.g., POSIX.1-2001),
> sync() schedules the writes,
>        but may return before the actual writing is done.  However, since
> version 1.3.20 Linux  does
>        actually  wait.   (This  still  does  not  guarantee data integrity:
> modern disks have large
>        caches.)
> 
> maybe that's your culprit?


I may have reading problems but... I understand:

 *  According  to  the standard specification (e.g., POSIX.1-2001), sync() 
schedules the writes,    but may return before the actual writing is done.  
===============
According to posix, "sync" means you ask to sync. It does not wait to the 
acutal data to be written to the disk.


*  However, since version 1.3.20 Linux  does actually  wait. 
=================
Hoever on linux it does. 


* (This  still  does  not  guarantee data integrity: modern disks have large       
caches.)
==============
Using nand, cache is meaninless here, writing time is ... millisecs?

And, again - I issued a umount, please remember that. (Amos - thanks, code 
will be fixed to use directly the system call).