O_DIRECT fails in some kernel and FS

Ricardo Galli (gallir@uib.es)
Fri, 1 Feb 2002 21:37:05 +0100

After some comments from Oliver Diedrich (editor of heise.de), which told me
he couldn't make O_DIRECT work on 2.4.17, I tried with different versions and
file systems:

This is the result:

2.4.14 - Ext[23] - redhat7.2 glibs: OK (at least the bytes are written)
2.4.17 - ReiserFS - Debian Sid : FAILS (0 bytes file, write returns -1)
2.4.17 - Ext2 - Debian Woody : OK (bytes written)
2.4.17 - Ext3 - Debian Woody : FAILS (0 bytes file, write returns -1)

Oliver Diedrich also told he could make work O_DIRECT with ext3 and 2.4.17.

Is this normal? Does it really work on 2.4.14? Or it doesn't but the kernel
doesn't avoid caching?

Funny behaviour...

Regards,

-- 
  ricardo
"I just stopped using Windows and now you tell me to use Mirrors?" 
    - said Aunt Tillie, just before downloading 2.5.3 kernel.
-
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