linux/fs/nfs/blocklayout
Kinglong Mee 15ae2c7bdc nfs/blocklayout: Fix bad using of page offset in bl_read_pagelist
Blocklayout uses file offset for the read-back page's offset of first writing,
it's definitely wrong, it writes data to bad address of page that cause userspace
application segment fault. It must be the page base stored in header->args.pgbase.

Also, the pg_offset has no influence with isect and extent length.

Note: The offset of the non-first page is always zero.

Ps: A test program will segment fault at read() as,
#define _GNU_SOURCE

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>

int main(int argc, char **argv)
{
        char buf[2049];
        char *filename = NULL;
        int fd = -1;

        if (argc < 2) {
                printf("Usage: %s filename\n", argv[0]);
                return 0;
        }

        filename = argv[1];
        fd = open(filename, O_RDONLY | O_DIRECT);
        if (fd < 0) {
                printf("Open %s fail: %m\n", filename);
                return 1;
        }

        lseek(fd, 2048, SEEK_SET);
        if (read(fd, buf, sizeof(buf) - 1) != (sizeof(buf) - 1))
                printf("Read 4096 bityes data from %s fail: %m\n", filename);
out:
        close(fd);
        return 0;
}

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-10-21 15:55:47 -05:00
..
Makefile pnfs/blocklayout: in-kernel GETDEVICEINFO XDR parsing 2014-09-12 13:33:50 -04:00
blocklayout.c nfs/blocklayout: Fix bad using of page offset in bl_read_pagelist 2015-10-21 15:55:47 -05:00
blocklayout.h pnfs: move common blocklayout XDR defintions to nfs4.h 2015-08-17 13:22:49 -05:00
dev.c pnfs/blocklayout: pass proper file mode to blkdev_get/put 2015-08-17 13:22:49 -05:00
extent_tree.c pnfs: move common blocklayout XDR defintions to nfs4.h 2015-08-17 13:22:49 -05:00
rpc_pipefs.c Merge branch 'iov_iter' into for-next 2014-12-08 20:39:29 -05:00