[Dovecot] Re: Bug? 1.0.0-test28 NFS locking problems

[Tim Southerwood]

On Thu, 22 Jul 2004 14:08:41 +0200
Matthias Andree <matthias.andree at gmx.de> wrote:

> Tim Southerwood <ts at doc.ic.ac.uk> writes:
> 
> > 1) fcntl with F_SETLKW will not work against a Solaris 2.8 server as
> > proved with a small test program. Other forms of fcntl (ie F_SETLK)
> > are OK.
> 
> Why not? Can you show the test program?

Don't  know why yet - I assume it's unimplemented in the Solaris NFS
dialect?

Here's the test program, fcntltest.c

//*********************************************************

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>

main(int argc, char* argv[])
{
	if (argc != 2)
	{
		fprintf (stderr, "Usage: %s filetolock\n", argv[0]);
		return(1);
	}
	
	int result;
	int fd;
	struct flock lock;
	char *filetolock;
	int locked=0;
	
	filetolock = argv[1];
	fd = open(filetolock, O_RDWR);
	if (fd == -1)
	{
		fprintf(stderr, filetolock);
		perror (" - error opening file");
		return(2);
	}

  	lock.l_type = F_RDLCK;     /* F_RDLCK, F_WRLCK, F_UNLCK */
  	lock.l_start = 0;  /* byte offset relative to l_whence */
  	lock.l_whence = SEEK_SET; /* SEEK_SET, SEEK_CUR, SEEK_END */
  	lock.l_len = 0;       /* #bytes (0 means to EOF) */

	result = fcntl(fd, F_SETLKW, &lock);
	if (result == -1)
	{
		perror("Error locking file with F_SETLKW");
	}
	else
	{
		printf("Locked with F_SETLKW\n");
		locked=1;
	}
	if (!locked)
	{
		result = fcntl(fd, F_SETLK, &lock);
		if (result == -1)
		{
			perror("Error locking file with F_SETLK");
		}
		else
		{
			printf ("Locked with F_SETLK\n");
		locked=1;
		}
	}
	if (locked)
	{
		printf("Sleeping - try to lock same file from second
process\n");		sleep(30);
	}
	close(fd);
	printf("File closed\n");
}

//*********************************************************


gcc -o fcntltest fcntltest.c

# The linux NFS server from linux client
#
ts at lenin > ./fcntltest /vol/csg/public/users/ts/wibble.blah 
Locked with F_SETLKW
Sleeping - try to lock same file from second process
File closed

# The local filesystem
#
ts at lenin > ./fcntltest /tmp/p.ps
Locked with F_SETLKW
Sleeping - try to lock same file from second process
File closed

# The Solaris 2.8 server
#
ts at lenin > ./fcntltest /homes/ts/liquid-1.0.0.tar.gz
Error locking file with F_SETLKW: No locks available
Locked with F_SETLK
Sleeping - try to lock same file from second process
File closed

That seems to verify it in my setup.

Cheers

Tim

-- 
Tim J Southerwood
Senior Programmer
CSG, Dept of Computing, Imperial College, London


-- 
Mr Tim J Southerwood
Senior Programmer
CSG, Dept of Computing, Imperial College, London
Email personal: ts at dionic.net work: ts at doc.ic.ac.uk
Tel home: +44 (0)1892 824850 mobile: +44 (0)7739-902439 work: +44 (0)20-759-48392
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