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-rw-r--r--btrfs-map-logical.c363
1 files changed, 363 insertions, 0 deletions
diff --git a/btrfs-map-logical.c b/btrfs-map-logical.c
new file mode 100644
index 00000000..fd0286d5
--- /dev/null
+++ b/btrfs-map-logical.c
@@ -0,0 +1,363 @@
+/*
+ * 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 "ctree.h"
+#include "volumes.h"
+#include "disk-io.h"
+#include "print-tree.h"
+#include "transaction.h"
+#include "list.h"
+#include "utils.h"
+
+#define BUFFER_SIZE (64 * 1024)
+
+/* 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_foward)
+{
+ 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;
+
+ ret = btrfs_search_slot(NULL, fs_info->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_foward && key.objectid < logical) ||
+ (!search_foward && key.objectid > logical) ||
+ (key.type != BTRFS_EXTENT_ITEM_KEY &&
+ key.type != BTRFS_METADATA_ITEM_KEY)) {
+ if (!search_foward)
+ ret = btrfs_previous_extent_item(fs_info->extent_root,
+ path, 0);
+ else
+ ret = btrfs_next_item(fs_info->extent_root, path);
+ if (ret)
+ goto out;
+ goto again;
+ }
+ logical = key.objectid;
+ if (key.type == BTRFS_METADATA_ITEM_KEY)
+ len = fs_info->tree_root->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->mapping_tree, READ,
+ logical + cur_offset, &cur_len,
+ &multi, mirror_num, NULL);
+ if (ret) {
+ fprintf(info_file,
+ "Error: fails to map mirror%d logical %llu: %s\n",
+ mirror_num, logical, strerror(-ret));
+ return ret;
+ }
+ for (i = 0; i < multi->num_stripes; i++) {
+ device = multi->stripes[i].dev;
+ fprintf(info_file,
+ "mirror %d logical %Lu physical %Lu device %s\n",
+ mirror_num, logical + cur_offset,
+ multi->stripes[0].physical,
+ device->name);
+ }
+ kfree(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->mapping_tree, 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->tree_root, buffer,
+ logical + cur_offset, &cur_len, mirror);
+ if (ret < 0) {
+ fprintf(stderr,
+ "Failed to read extent at [%llu, %llu]: %s\n",
+ logical, logical + length, strerror(-ret));
+ return ret;
+ }
+ ret = write(out_fd, buffer, cur_len);
+ if (ret < 0 || ret != cur_len) {
+ if (ret > 0)
+ ret = -EINTR;
+ fprintf(stderr, "output file write failed: %s\n",
+ strerror(-ret));
+ return ret;
+ }
+ cur_offset += cur_len;
+ }
+ return ret;
+}
+
+static void print_usage(void) __attribute__((noreturn));
+static void print_usage(void)
+{
+ fprintf(stderr, "usage: btrfs-map-logical [options] device\n");
+ fprintf(stderr, "\t-l Logical extent to map\n");
+ fprintf(stderr, "\t-c Copy of the extent to read (usually 1 or 2)\n");
+ fprintf(stderr, "\t-o Output file to hold the extent\n");
+ fprintf(stderr, "\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))
+ print_usage();
+ 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->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) {
+ fprintf(stderr, "Failed to find extent at [%llu,%llu): %s\n",
+ cur_logical, cur_logical + cur_len, strerror(-ret));
+ 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) {
+ fprintf(stderr,
+ "Failed to find extent at [%llu,%llu): %s\n",
+ cur_logical, cur_logical + cur_len,
+ strerror(-ret));
+ 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;
+ 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;
+}
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