[Samba] problem when writing to a deleted file
simon at gardencitygroup.com
Wed Mar 23 18:43:11 GMT 2005
I've got a weird situation. I have an RMI application that is creating
PDF's for a web server. A request comes in to the web server, the web
server deletes the PDF if it exists and then requests an RMI server to
create the PDF. The PDF is written directly to the web server's disk via
a Samba mount (both systems are Linux and are running Samba 3.0.10). The
problem occurs when the web server serves 2 almost simultaneous requests
for the same PDF. The first request deletes (if necessary) the existing
PDF and calls the RMI server to create a new PDF. The next request
deletes the PDF (that is now being created by the RMI server) and calls
the RMI server to create a new PDF. The first RMI process can no longer
write to the PDF and the second process can't write to it either. It's
very much a timing issue. If the requests are spread out just enough,
then no one's the wiser.
Samba generates the following error (from messages). I believe that
means that Samba is getting an EBADF error (bad file number).
kernel: smb_writepage_sync: failed write, wsize=4096, result=-9
What exactly is going on in the file system during this? I know what
happens in a normal UNIX file system (and the problem does not occur
there). I am going to write a test application that creates just plain
files without using the PDF library to see if perhaps they do something
funny or if it's just how Samba handles deleted files. I have a call
into the writers of the PDF library as well.
This seems like a silly problem and we'll probably have to code around
it anyway, but something is not working correctly (in my eye).
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