btrfs-progs/btrfs-map-logical.c
Josef Bacik db2ab47823 btrfs-progs: stop accessing ->extent_root directly
When we switch to multiple global trees we'll need to access the
appropriate extent root depending on the block group or possibly root.
To handle this, use a helper in most places and then the actual root in
places where it is required.  We will whittle down the direct accessors
with future patches, but this does the bulk of the preparatory work.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2021-11-30 18:56:54 +01:00

375 lines
8.8 KiB
C

/*
* Copyright (C) 2009 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <getopt.h>
#include "kerncompat.h"
#include "kernel-shared/ctree.h"
#include "kernel-shared/volumes.h"
#include "kernel-shared/disk-io.h"
#include "kernel-shared/print-tree.h"
#include "kernel-shared/transaction.h"
#include "kernel-lib/list.h"
#include "kernel-lib/radix-tree.h"
#include "common/utils.h"
#include "common/help.h"
#define BUFFER_SIZE SZ_64K
/* we write the mirror info to stdout unless they are dumping the data
* to stdout
* */
static FILE *info_file;
static int map_one_extent(struct btrfs_fs_info *fs_info,
u64 *logical_ret, u64 *len_ret, int search_forward)
{
struct btrfs_root *extent_root;
struct btrfs_path *path;
struct btrfs_key key;
u64 logical;
u64 len = 0;
int ret = 0;
BUG_ON(!logical_ret);
logical = *logical_ret;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
key.objectid = logical;
key.type = 0;
key.offset = 0;
extent_root = btrfs_extent_root(fs_info, logical);
ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
if (ret < 0)
goto out;
BUG_ON(ret == 0);
ret = 0;
again:
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
if ((search_forward && key.objectid < logical) ||
(!search_forward && key.objectid > logical) ||
(key.type != BTRFS_EXTENT_ITEM_KEY &&
key.type != BTRFS_METADATA_ITEM_KEY)) {
if (!search_forward)
ret = btrfs_previous_extent_item(extent_root,
path, 0);
else
ret = btrfs_next_extent_item(extent_root,
path, 0);
if (ret)
goto out;
goto again;
}
logical = key.objectid;
if (key.type == BTRFS_METADATA_ITEM_KEY)
len = fs_info->nodesize;
else
len = key.offset;
out:
btrfs_free_path(path);
if (!ret) {
*logical_ret = logical;
if (len_ret)
*len_ret = len;
}
return ret;
}
static int __print_mapping_info(struct btrfs_fs_info *fs_info, u64 logical,
u64 len, int mirror_num)
{
struct btrfs_multi_bio *multi = NULL;
u64 cur_offset = 0;
u64 cur_len;
int ret = 0;
while (cur_offset < len) {
struct btrfs_device *device;
int i;
cur_len = len - cur_offset;
ret = btrfs_map_block(fs_info, READ, logical + cur_offset,
&cur_len, &multi, mirror_num, NULL);
if (ret) {
errno = -ret;
fprintf(info_file,
"Error: fails to map mirror%d logical %llu: %m\n",
mirror_num, logical);
return ret;
}
for (i = 0; i < multi->num_stripes; i++) {
device = multi->stripes[i].dev;
fprintf(info_file,
"mirror %d logical %llu physical %llu device %s\n",
mirror_num, logical + cur_offset,
multi->stripes[0].physical,
device->name);
}
free(multi);
multi = NULL;
cur_offset += cur_len;
}
return ret;
}
/*
* Logical and len is the exact value of a extent.
* And offset is the offset inside the extent. It's only used for case
* where user only want to print part of the extent.
*
* Caller *MUST* ensure the range [logical,logical+len) are in one extent.
* Or we can encounter the following case, causing a -ENOENT error:
* |<-----given parameter------>|
* |<------ Extent A ----->|
*/
static int print_mapping_info(struct btrfs_fs_info *fs_info, u64 logical,
u64 len)
{
int num_copies;
int mirror_num;
int ret = 0;
num_copies = btrfs_num_copies(fs_info, logical, len);
for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
ret = __print_mapping_info(fs_info, logical, len, mirror_num);
if (ret < 0)
return ret;
}
return ret;
}
/* Same requisition as print_mapping_info function */
static int write_extent_content(struct btrfs_fs_info *fs_info, int out_fd,
u64 logical, u64 length, int mirror)
{
char buffer[BUFFER_SIZE];
u64 cur_offset = 0;
u64 cur_len;
int ret = 0;
while (cur_offset < length) {
cur_len = min_t(u64, length - cur_offset, BUFFER_SIZE);
ret = read_extent_data(fs_info, buffer,
logical + cur_offset, &cur_len, mirror);
if (ret < 0) {
errno = -ret;
fprintf(stderr,
"Failed to read extent at [%llu, %llu]: %m\n",
logical, logical + length);
return ret;
}
ret = write(out_fd, buffer, cur_len);
if (ret < 0 || ret != cur_len) {
if (ret > 0)
ret = -EINTR;
errno = -ret;
fprintf(stderr, "output file write failed: %m\n");
return ret;
}
cur_offset += cur_len;
}
return ret;
}
__attribute__((noreturn))
static void print_usage(void)
{
printf("usage: btrfs-map-logical [options] device\n");
printf("\t-l Logical extent to map\n");
printf("\t-c Copy of the extent to read (usually 1 or 2)\n");
printf("\t-o Output file to hold the extent\n");
printf("\t-b Number of bytes to read\n");
exit(1);
}
int main(int argc, char **argv)
{
struct cache_tree root_cache;
struct btrfs_root *root;
char *dev;
char *output_file = NULL;
u64 copy = 0;
u64 logical = 0;
u64 bytes = 0;
u64 cur_logical = 0;
u64 cur_len = 0;
int out_fd = -1;
int found = 0;
int ret = 0;
while(1) {
int c;
static const struct option long_options[] = {
/* { "byte-count", 1, NULL, 'b' }, */
{ "logical", required_argument, NULL, 'l' },
{ "copy", required_argument, NULL, 'c' },
{ "output", required_argument, NULL, 'o' },
{ "bytes", required_argument, NULL, 'b' },
{ NULL, 0, NULL, 0}
};
c = getopt_long(argc, argv, "l:c:o:b:", long_options, NULL);
if (c < 0)
break;
switch(c) {
case 'l':
logical = arg_strtou64(optarg);
break;
case 'c':
copy = arg_strtou64(optarg);
break;
case 'b':
bytes = arg_strtou64(optarg);
break;
case 'o':
output_file = strdup(optarg);
break;
default:
print_usage();
}
}
set_argv0(argv);
if (check_argc_min(argc - optind, 1))
return 1;
if (logical == 0)
print_usage();
dev = argv[optind];
radix_tree_init();
cache_tree_init(&root_cache);
root = open_ctree(dev, 0, 0);
if (!root) {
fprintf(stderr, "Open ctree failed\n");
free(output_file);
exit(1);
}
info_file = stdout;
if (output_file) {
if (strcmp(output_file, "-") == 0) {
out_fd = 1;
info_file = stderr;
} else {
out_fd = open(output_file, O_RDWR | O_CREAT, 0600);
if (out_fd < 0)
goto close;
ret = ftruncate(out_fd, 0);
if (ret) {
ret = 1;
close(out_fd);
goto close;
}
info_file = stdout;
}
}
if (bytes == 0)
bytes = root->fs_info->nodesize;
cur_logical = logical;
cur_len = bytes;
/* First find the nearest extent */
ret = map_one_extent(root->fs_info, &cur_logical, &cur_len, 0);
if (ret < 0) {
errno = -ret;
fprintf(stderr, "Failed to find extent at [%llu,%llu): %m\n",
cur_logical, cur_logical + cur_len);
goto out_close_fd;
}
/*
* Normally, search backward should be OK, but for special case like
* given logical is quite small where no extents are before it,
* we need to search forward.
*/
if (ret > 0) {
ret = map_one_extent(root->fs_info, &cur_logical, &cur_len, 1);
if (ret < 0) {
errno = -ret;
fprintf(stderr,
"Failed to find extent at [%llu,%llu): %m\n",
cur_logical, cur_logical + cur_len);
goto out_close_fd;
}
if (ret > 0) {
fprintf(stderr,
"Failed to find any extent at [%llu,%llu)\n",
cur_logical, cur_logical + cur_len);
goto out_close_fd;
}
}
while (cur_logical + cur_len >= logical && cur_logical < logical +
bytes) {
u64 real_logical;
u64 real_len;
found = 1;
ret = map_one_extent(root->fs_info, &cur_logical, &cur_len, 1);
if (ret < 0)
goto out_close_fd;
if (ret > 0)
break;
/* check again if there is overlap. */
if (cur_logical + cur_len < logical ||
cur_logical >= logical + bytes)
break;
real_logical = max(logical, cur_logical);
real_len = min(logical + bytes, cur_logical + cur_len) -
real_logical;
ret = print_mapping_info(root->fs_info, real_logical, real_len);
if (ret < 0)
goto out_close_fd;
if (output_file && out_fd != -1) {
ret = write_extent_content(root->fs_info, out_fd,
real_logical, real_len, copy);
if (ret < 0)
goto out_close_fd;
}
cur_logical += cur_len;
}
if (!found) {
fprintf(stderr, "No extent found at range [%llu,%llu)\n",
logical, logical + bytes);
}
out_close_fd:
if (output_file && out_fd != 1)
close(out_fd);
close:
free(output_file);
close_ctree(root);
if (ret < 0)
ret = 1;
btrfs_close_all_devices();
return ret;
}