[Openmosix-devel] oMFS bug?

[Moreno B. <ba...@de...>]

Hi devel-oMers,

here's a simple demo which shows the effect of the oMFS bug(?) that mess
up coreutils-cp.

stat() and fstat() syscalls, on the same file, should set an identycal
'stat' structure (the former needs a filename, the latter a file
descriptor).
This is not true when these calls get the info for any mfs file: the
st_dev field looks different.

Try to run this code against any file (or dir) on local filesystem and
then try it against any mfs file.

For instance:
	./mfs_stat_bug	/
	./mfs_stat_bug	/net/mfs/here

Take a look at st_dev on the latter example. First 4 bytes seem ok,
should be 8 but look like st_dev, then... mmh, looks like the node
number...  %->

Two examples, st_dev printed as dev_t (uint64_t, unsigned long long):

	/mfs/2:  0x08050002000000ff
	/mfs/21: 0x08050015000000ff

I can suppose that:
- first 4 bytes (int32_t!) is st_dev: 0x000000ff
- 2 bytes as node number (int16_t?)
	node 2  = 0x0002
	node 21 = 0x0015
	(this weird theory works for other nodes-number too)
but what are the last 4 bytes: 0x0805? (0x0100, 0x0302 on other oM
clusters)

Anyway, suppositions aside, is it a problem of boundaries?

Moshe, Vincent, any mfs hacker all over the world, is there a bug?

Am I paranoid? :)

Ciao

Moreno