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https://github.com/ibm-s390-linux/s390-tools.git
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296079f70a
from disk.c to a dedicated source file fs-map.c, so that the new zipl-editenv tool will be also able to use it. Reviewed-by: Stefan Haberland <sth@linux.ibm.com> Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com> Signed-off-by: Eduard Shishkin <edward6@linux.ibm.com> Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
128 lines
2.9 KiB
C
128 lines
2.9 KiB
C
/*
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* zipl - zSeries Initial Program Loader tool
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*
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* Functions to map logical addresses to physical ones
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*
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* Copyright IBM Corp. 2001, 2017
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*
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* s390-tools is free software; you can redistribute it and/or modify
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* it under the terms of the MIT license. See LICENSE for details.
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*/
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/ioctl.h>
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#include <sys/stat.h>
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#include <sys/vfs.h>
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#include <unistd.h>
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#include <linux/fs.h>
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#include <linux/fiemap.h>
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#include "disk.h"
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#include "error.h"
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#include "misc.h"
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#ifndef REISERFS_SUPER_MAGIC
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#define REISERFS_SUPER_MAGIC 0x52654973
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#endif /* not REISERFS_SUPER_MAGIC */
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#ifndef REISERFS_IOC_UNPACK
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#define REISERFS_IOC_UNPACK _IOW(0xCD, 1, long)
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#endif /* not REISERFS_IOC_UNPACK */
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/**
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* Filesystem-specific hook.
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* Do whatever needed before mapping logical address to physical one
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*/
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static int fs_premap_hook(int fd)
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{
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struct statfs buf;
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/* Get file system type */
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if (fstatfs(fd, &buf)) {
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error_reason(strerror(errno));
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return -1;
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}
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switch (buf.f_type) {
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case REISERFS_SUPER_MAGIC:
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/* Files on ReiserFS need unpacking */
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if (ioctl(fd, REISERFS_IOC_UNPACK, 1)) {
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error_reason("Could not unpack ReiserFS file");
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return -1;
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}
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break;
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default:
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break;
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}
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return 0;
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}
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/**
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* Find a disk address for a file system block,
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* where a specified byte of the file body is located
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*
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* FD: file descriptor
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* OFFSET: offset of the byte in the file body
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* MAPPED: resulted disk address
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* FS_BLOCK_SIZE : file system block size in bytes
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*/
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int fs_map(int fd, uint64_t offset, blocknum_t *mapped,
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int fs_block_size)
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{
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struct fiemap *fiemap;
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int fiemap_size;
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int map_offset;
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int block;
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if (fs_premap_hook(fd))
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return -1;
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/*
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* First try FIEMAP, more complicated to set up
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*/
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fiemap_size = sizeof(struct fiemap) + sizeof(struct fiemap_extent);
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fiemap = misc_malloc(fiemap_size);
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if (!fiemap)
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return -1;
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memset(fiemap, 0, fiemap_size);
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fiemap->fm_extent_count = 1;
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fiemap->fm_flags = FIEMAP_FLAG_SYNC;
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fiemap->fm_start = offset;
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fiemap->fm_length = fs_block_size;
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if (ioctl(fd, FS_IOC_FIEMAP, (unsigned long)fiemap)) {
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/* FIEMAP failed, fall back to FIBMAP */
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block = offset / fs_block_size;
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if (ioctl(fd, FIBMAP, &block)) {
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error_reason("Could not get file mapping");
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free(fiemap);
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return -1;
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}
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*mapped = block;
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} else {
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if (fiemap->fm_mapped_extents) {
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if (fiemap->fm_extents[0].fe_flags &
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FIEMAP_EXTENT_ENCODED) {
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error_reason("File mapping is encoded");
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free(fiemap);
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return -1;
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}
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/*
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* returned extent may start prior to our request
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*/
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map_offset = fiemap->fm_start -
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fiemap->fm_extents[0].fe_logical;
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*mapped = fiemap->fm_extents[0].fe_physical +
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map_offset;
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/* set mapped to fs block units */
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*mapped = *mapped / fs_block_size;
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} else {
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*mapped = 0;
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}
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}
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free(fiemap);
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return 0;
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}
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