[Gluster-users] strange "permission denied" problem

[Nikolai Grigoriev]

Hi,

I am new to gluster and would appreciate if someone could help me to
understand what may be wrong.

We have a small filesystem (currently - just one brick) and on the same
client node I have two processes. One is writing files to a specific
glusterfs share and another one is periodically scanning that directory and
loading all the files from there. Files are small, hundreds of bytes at
most. There are not too many files written, maybe one in a couple of
seconds.

Quite often (about 20% of the cases) the "consumer" process fails to open
the file written by the "producer". The producer does create a temporary
file first and then renames it to its final name. Both processes are Java
apps.

Producer writes the file as follows:

4957  18:15:37 open("/share/fileXYZ.settings", O_WRONLY|O_CREAT|
O_TRUNC, 0666) = 245 <0.001671>

The consumer does this:

2030  04:26:11 stat("/share/fileXYZ.settings.settings",
{st_mode=S_IFREG|0644, st_size=556, ...}) = 0 <0.000006>
2030  04:26:11 access("/share/fileXYZ.settings.settings", R_OK) = 0
<0.000006>
2030  04:26:11 open("/share/fileXYZ.settings.settings", O_RDONLY) = -1
EACCES (Permission denied) <0.000258>

Interestingly enough, if the consumer retries then the file most likely
will be readable. Very strange - especially considering that access()
returns 0 just before open().

It does look like the problem of this specific filesystem - if the same app
is used against a local directory than it works flawlessly.



-- 
Nikolai Grigoriev
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