Date: Tue, 20 May 1997 16:24:03 +0000 From: Kachun Lee <kachun@zippo.com> To: dfr@nlsystems.com (Doug Rabson) Cc: freebsd-stable@freebsd.org Subject: Re: can anyone confirm my NFS/VM problem? Message-ID: <3.0.1.32.19970520162403.007167ec@dopey.pathlink.com>
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> Well I think I have a fix. It was bloody painful too. There were some
> extremely ugly problems associated with NFS' use of b_validoff and
> b_validend. I attempted to fix them but it still feels pretty fragile
> although it does pass Ghristoph's test case.
I am wondering if you would look into another problem related to NFS/MMAP.
Accessing a mmap NFS file when the file is deleted from the server will
result with following error:
May 20 16:02:02 lacy /kernel: vnode_pager_getpages: I/O read error
May 20 16:02:02 lacy /kernel: vm_fault: pager input (probably hardware)
error, P
ID 522 failure
I applied the above patch to the lastest 22-releng and it did not fix this
problem. I wrote a simple C program to duplicate the problem. It will open
and mmap a file, read it, then wait for a key and read it again. So the
file can be deleted between keys. BTW, I normally need to wait for 5+
minutes after the file is deleted before I can see the error message.
Best regards
PS: The NFSV3 diroff memory leak is resolved... thanks again.
--------------------------------------------
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
main(int ac, char **av)
{
int c;
while(ac-- > 1)
{
++av;
int fdin = open(*av, O_RDONLY);
if(fdin < 0)
{
fprintf(stderr,"Cannot open %s\n", *av);
continue;
}
struct stat sb;
if(fstat(fdin, &sb) < 0)
{
fprintf(stderr,"Cannot stat %s\n", *av);
close(fdin);
continue;
}
char * pmap = mmap(0, sb.st_size, PROT_READ,
MAP_SHARED, fdin, 0);
if(((int)pmap) < 0)
{
perror("Cannot map file");
close(fdin);
continue;
}
for(c=0;c>=0;)
{
write(1, pmap, sb.st_size);
while((c=getchar()) >= 0) if(c == '\n') break;
extern int errno;
if(fstat(fdin, &sb) < 0)
fprintf(stderr, "fstat error: %s\n",
strerror(errno));
}
close(fdin);
munmap(pmap, sb.st_size);
}
}
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