Messages in this thread |  | | Date | Wed, 9 May 2001 12:55:51 +0200 | From | Kurt Garloff <> | Subject | Re: nfs MAP_SHARED corruption fix |
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Hi Andrea, Trond,
the demo for the NFS SHARED_MAP corruption:
garloff@daubechies:~/C $ uname -sr Linux 2.4.4 garloff@daubechies:~/C $ ./test_nfs_shared_map ; head -1 ./testfile; sleep 10; head -1 ./testfile Linux NFS rocks. Linux NFS sucks.
Sources attached. I still have to test your fix, Trond.
Regards, -- Kurt Garloff <garloff@suse.de> Eindhoven, NL GPG key: See mail header, key servers Linux kernel development SuSE GmbH, Nuernberg, FRG SCSI, Security /** test_nfs_shared_map.c * * Creates a file, expands it by ftruncate, mmaps it, writes * to the mapped memory, unmaps it and closes the file again. * * This triggers a bug in 2.4.4 NFS client code: The file won't * contain the data written to the mapped memory. * * (c) Kurt Garloff <garloff@suse.de>, 2001-05-09, GNU GPL */
#include <stdio.h> #include <string.h> #include <unistd.h> #include <fcntl.h> #include <sys/mman.h> #include <errno.h>
const char * const bad = "Linux NFS sucks.\n"; const char * const good = "Linux NFS rocks.\n"; const char * const name = "testfile";
#define LEN 4096
int die (const char* const txt) { perror (txt); exit (errno); }
int main () { char* adr; int err; int fd = open (name, O_RDWR | O_CREAT | O_TRUNC, 0644); if (fd <= 0) die ("create testfile"); err = write (fd, bad, strlen (bad)); close (fd); truncate (name, LEN); sync (); fd = open (name, O_RDWR); if (fd <= 0) die ("open testfile"); adr = (char*) mmap (0, LEN, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); if (!adr) die ("mmap failed"); strcpy (adr, good); strcpy (adr+32, good); #ifdef NEED_MSYNC msync (adr, LEN, MS_SYNC); #endif munmap (adr, LEN); close (fd); } [unhandled content-type:application/pgp-signature] |  |