VFAT: flush mount option

luca ellero lroluk at gmail.com
Thu Apr 21 05:41:33 EDT 2011

Hi all,
I've read somewhere that the suggested mount option for USB key with FAT 
filesystem is "-o flush" instead of "-o sync" (if you want to remove the 
key safely, without executing umount or sync). sync option is quite 
dangerous (and slow) for flash file-systems since it does an aggressive 
flushing on the FAT, which can damage the flash.
Anyway with flush option (kernel 2.6.32), I experienced the following:
- if I create or modify a file on the key, the fs is sync'ed immediately 
so I can pull out the key immediately with no side effects
- but if I only create a directory and anything else, the "flush" is not 
executed immediately, so if I pull out the key, the directory just 
created disappear (which is not what I would expect).
Can someone please tell me if this is the right behaviour or am I 
missing something.
Best regards
Luca Ellero

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