Testing btrfs physical offset
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549
docs/btrfs-offset/btrfs_map_physical.c
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549
docs/btrfs-offset/btrfs_map_physical.c
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// SPDX-FileCopyrightText: Omar Sandoval <osandov@osandov.com>
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// SPDX-License-Identifier: MIT
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#include <fcntl.h>
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#include <getopt.h>
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#include <inttypes.h>
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/ioctl.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <linux/btrfs.h>
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#include <linux/btrfs_tree.h>
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#include <asm/byteorder.h>
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#define le16_to_cpu __le16_to_cpu
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#define le32_to_cpu __le32_to_cpu
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#define le64_to_cpu __le64_to_cpu
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static const char *progname = "btrfs_map_physical";
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static void usage(bool error)
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{
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fprintf(error ? stderr : stdout,
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"usage: %s [OPTION]... PATH\n"
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"\n"
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"Map the logical and physical extents of a file on Btrfs\n\n"
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"Pipe this to `column -ts $'\\t'` for prettier output.\n"
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"\n"
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"Btrfs represents a range of data in a file with a \"file extent\". Each\n"
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"file extent refers to a subset of an \"extent\". Each extent has a\n"
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"location in the logical address space of the filesystem belonging to a\n"
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"\"chunk\". Each chunk maps has a profile (i.e., RAID level) and maps to\n"
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"one or more physical locations, or \"stripes\", on disk. The extent may be\n"
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"\"encoded\" on disk (currently this means compressed, but in the future it\n"
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"may also be encrypted).\n"
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"\n"
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"An explanation of each printed field and its corresponding on-disk data\n"
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"structure is provided below:\n"
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"\n"
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"FILE OFFSET Offset in the file where the file extent starts\n"
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" [(struct btrfs_key).offset]\n"
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"FILE SIZE Size of the file extent\n"
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" [(struct btrfs_file_extent_item).num_bytes for most\n"
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" extents, (struct btrfs_file_extent_item).ram_bytes\n"
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" for inline extents]\n"
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"EXTENT OFFSET Offset from the beginning of the unencoded extent\n"
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" where the file extent starts\n"
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" [(struct btrfs_file_extent_item).offset]\n"
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"EXTENT TYPE Type of the extent (inline, preallocated, etc.)\n"
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" [(struct btrfs_file_extent_item).type];\n"
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" how it is encoded\n"
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" [(struct btrfs_file_extent_item){compression,\n"
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" encryption,other_encoding}];\n"
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" and its data profile\n"
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" [(struct btrfs_chunk).type]\n"
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"LOGICAL SIZE Size of the unencoded extent\n"
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" [(struct btrfs_file_extent_item).ram_bytes]\n"
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"LOGICAL OFFSET Location of the extent in the filesystem's logical\n"
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" address space\n"
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" [(struct btrfs_file_extent_offset).disk_bytenr]\n"
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"PHYSICAL SIZE Size of the encoded extent on disk\n"
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" [(struct btrfs_file_extent_offset).disk_num_bytes]\n"
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"DEVID ID of the device containing the extent\n"
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" [(struct btrfs_stripe).devid]\n"
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"PHYSICAL OFFSET Location of the extent on the device\n"
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" [calculated from (struct btrfs_stripe).offset]\n"
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"\n"
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"FILE SIZE is rounded up to the sector size of the filesystem.\n"
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"\n"
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"Inline extents are stored with the metadata of the filesystem; this tool\n"
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"does not have the ability to determine their location.\n"
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"\n"
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"Gaps in a file are represented with a hole file extent unless the\n"
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"filesystem was formatted with the \"no-holes\" option.\n"
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"\n"
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"If the file extent was truncated, hole punched, cloned, or deduped,\n"
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"EXTENT OFFSET may be non-zero and LOGICAL SIZE may be different from\n"
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"FILE SIZE.\n"
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"\n"
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"Options:\n"
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" -h, --help display this help message and exit\n",
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progname);
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exit(error ? EXIT_FAILURE : EXIT_SUCCESS);
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}
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struct stripe {
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uint64_t devid;
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uint64_t offset;
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};
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struct chunk {
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uint64_t offset;
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uint64_t length;
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uint64_t stripe_len;
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uint64_t type;
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struct stripe *stripes;
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size_t num_stripes;
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size_t sub_stripes;
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};
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struct chunk_tree {
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struct chunk *chunks;
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size_t num_chunks;
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};
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static int read_chunk_tree(int fd, struct chunk **chunks, size_t *num_chunks)
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{
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struct btrfs_ioctl_search_args search = {
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.key = {
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.tree_id = BTRFS_CHUNK_TREE_OBJECTID,
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.min_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID,
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.min_type = BTRFS_CHUNK_ITEM_KEY,
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.min_offset = 0,
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.max_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID,
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.max_type = BTRFS_CHUNK_ITEM_KEY,
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.max_offset = UINT64_MAX,
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.min_transid = 0,
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.max_transid = UINT64_MAX,
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.nr_items = 0,
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},
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};
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size_t items_pos = 0, buf_off = 0;
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size_t capacity = 0;
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int ret;
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*chunks = NULL;
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*num_chunks = 0;
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for (;;) {
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const struct btrfs_ioctl_search_header *header;
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const struct btrfs_chunk *item;
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struct chunk *chunk;
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size_t i;
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if (items_pos >= search.key.nr_items) {
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search.key.nr_items = 4096;
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ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &search);
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if (ret == -1) {
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perror("BTRFS_IOC_TREE_SEARCH");
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return -1;
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}
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items_pos = 0;
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buf_off = 0;
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if (search.key.nr_items == 0)
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break;
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}
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header = (struct btrfs_ioctl_search_header *)(search.buf + buf_off);
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if (header->type != BTRFS_CHUNK_ITEM_KEY)
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goto next;
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item = (void *)(header + 1);
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if (*num_chunks >= capacity) {
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struct chunk *tmp;
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if (capacity == 0)
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capacity = 1;
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else
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capacity *= 2;
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tmp = realloc(*chunks, capacity * sizeof(**chunks));
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if (!tmp) {
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perror("realloc");
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return -1;
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}
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*chunks = tmp;
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}
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chunk = &(*chunks)[*num_chunks];
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chunk->offset = header->offset;
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chunk->length = le64_to_cpu(item->length);
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chunk->stripe_len = le64_to_cpu(item->stripe_len);
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chunk->type = le64_to_cpu(item->type);
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chunk->num_stripes = le16_to_cpu(item->num_stripes);
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chunk->sub_stripes = le16_to_cpu(item->sub_stripes);
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chunk->stripes = calloc(chunk->num_stripes,
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sizeof(*chunk->stripes));
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if (!chunk->stripes) {
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perror("calloc");
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return -1;
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}
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(*num_chunks)++;
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for (i = 0; i < chunk->num_stripes; i++) {
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const struct btrfs_stripe *stripe;
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stripe = &item->stripe + i;
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chunk->stripes[i].devid = le64_to_cpu(stripe->devid);
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chunk->stripes[i].offset = le64_to_cpu(stripe->offset);
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}
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next:
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items_pos++;
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buf_off += sizeof(*header) + header->len;
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if (header->offset == UINT64_MAX)
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break;
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else
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search.key.min_offset = header->offset + 1;
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}
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return 0;
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}
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static struct chunk *find_chunk(struct chunk *chunks, size_t num_chunks,
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uint64_t logical)
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{
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size_t lo, hi;
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if (!num_chunks)
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return NULL;
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lo = 0;
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hi = num_chunks - 1;
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while (lo <= hi) {
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size_t mid = lo + (hi - lo) / 2;
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if (logical < chunks[mid].offset)
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hi = mid - 1;
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else if (logical >= chunks[mid].offset + chunks[mid].length)
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lo = mid + 1;
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else
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return &chunks[mid];
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}
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return NULL;
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}
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static int print_extents(int fd, struct chunk *chunks, size_t num_chunks)
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{
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struct btrfs_ioctl_search_args search = {
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.key = {
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.min_type = BTRFS_EXTENT_DATA_KEY,
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.max_type = BTRFS_EXTENT_DATA_KEY,
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.min_offset = 0,
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.max_offset = UINT64_MAX,
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.min_transid = 0,
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.max_transid = UINT64_MAX,
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.nr_items = 0,
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},
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};
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struct btrfs_ioctl_ino_lookup_args args = {
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.treeid = 0,
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.objectid = BTRFS_FIRST_FREE_OBJECTID,
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};
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size_t items_pos = 0, buf_off = 0;
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struct stat st;
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int ret;
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puts("FILE OFFSET\tFILE SIZE\tEXTENT OFFSET\tEXTENT TYPE\tLOGICAL SIZE\tLOGICAL OFFSET\tPHYSICAL SIZE\tDEVID\tPHYSICAL OFFSET");
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ret = fstat(fd, &st);
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if (ret == -1) {
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perror("fstat");
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return -1;
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}
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ret = ioctl(fd, BTRFS_IOC_INO_LOOKUP, &args);
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if (ret == -1) {
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perror("BTRFS_IOC_INO_LOOKUP");
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return -1;
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}
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search.key.tree_id = args.treeid;
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search.key.min_objectid = search.key.max_objectid = st.st_ino;
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for (;;) {
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const struct btrfs_ioctl_search_header *header;
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const struct btrfs_file_extent_item *item;
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uint8_t type;
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/* Initialize to silence GCC. */
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uint64_t file_offset = 0;
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uint64_t file_size = 0;
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uint64_t extent_offset = 0;
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uint64_t logical_size = 0;
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uint64_t logical_offset = 0;
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uint64_t physical_size = 0;
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struct chunk *chunk = NULL;
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if (items_pos >= search.key.nr_items) {
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search.key.nr_items = 4096;
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ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &search);
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if (ret == -1) {
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perror("BTRFS_IOC_TREE_SEARCH");
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return -1;
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}
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items_pos = 0;
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buf_off = 0;
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if (search.key.nr_items == 0)
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break;
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}
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header = (struct btrfs_ioctl_search_header *)(search.buf + buf_off);
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if (header->type != BTRFS_EXTENT_DATA_KEY)
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goto next;
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item = (void *)(header + 1);
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type = item->type;
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file_offset = header->offset;
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if (type == BTRFS_FILE_EXTENT_INLINE) {
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file_size = logical_size = le64_to_cpu(item->ram_bytes);
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extent_offset = 0;
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physical_size = (header->len -
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offsetof(struct btrfs_file_extent_item,
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disk_bytenr));
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} else if (type == BTRFS_FILE_EXTENT_REG ||
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type == BTRFS_FILE_EXTENT_PREALLOC) {
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file_size = le64_to_cpu(item->num_bytes);
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extent_offset = le64_to_cpu(item->offset);
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logical_size = le64_to_cpu(item->ram_bytes);
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logical_offset = le64_to_cpu(item->disk_bytenr);
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physical_size = le64_to_cpu(item->disk_num_bytes);
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if (logical_offset) {
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chunk = find_chunk(chunks, num_chunks,
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logical_offset);
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if (!chunk) {
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printf("\n");
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fprintf(stderr,
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"could not find chunk containing %" PRIu64 "\n",
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logical_offset);
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return -1;
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}
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}
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}
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printf("%" PRIu64 "\t", file_offset);
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if (type == BTRFS_FILE_EXTENT_INLINE ||
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type == BTRFS_FILE_EXTENT_REG ||
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type == BTRFS_FILE_EXTENT_PREALLOC) {
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printf("%" PRIu64 "\t%" PRIu64 "\t", file_size,
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extent_offset);
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} else {
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printf("\t\t");
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}
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switch (type) {
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case BTRFS_FILE_EXTENT_INLINE:
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printf("inline");
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break;
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case BTRFS_FILE_EXTENT_REG:
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if (logical_offset)
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printf("regular");
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else
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printf("hole");
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break;
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case BTRFS_FILE_EXTENT_PREALLOC:
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printf("prealloc");
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break;
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default:
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printf("type%u", type);
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break;
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}
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switch (item->compression) {
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case 0:
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break;
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case 1:
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printf(",compression=zlib");
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break;
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case 2:
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printf(",compression=lzo");
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break;
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case 3:
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printf(",compression=zstd");
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break;
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default:
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printf(",compression=%u", item->compression);
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break;
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}
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if (item->encryption)
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printf(",encryption=%u", item->encryption);
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if (item->other_encoding) {
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printf(",other_encoding=%u",
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le16_to_cpu(item->other_encoding));
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}
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if (chunk) {
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switch (chunk->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
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case 0:
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break;
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case BTRFS_BLOCK_GROUP_RAID0:
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printf(",raid0");
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break;
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case BTRFS_BLOCK_GROUP_RAID1:
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printf(",raid1");
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break;
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case BTRFS_BLOCK_GROUP_DUP:
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printf(",dup");
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break;
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case BTRFS_BLOCK_GROUP_RAID10:
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printf(",raid10");
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break;
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case BTRFS_BLOCK_GROUP_RAID5:
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printf(",raid5");
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break;
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case BTRFS_BLOCK_GROUP_RAID6:
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printf(",raid6");
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break;
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default:
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printf(",profile%" PRIu64,
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(uint64_t)(chunk->type &
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BTRFS_BLOCK_GROUP_PROFILE_MASK));
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break;
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}
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}
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printf("\t");
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if (type == BTRFS_FILE_EXTENT_INLINE ||
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type == BTRFS_FILE_EXTENT_REG ||
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type == BTRFS_FILE_EXTENT_PREALLOC)
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printf("%" PRIu64 "\t", logical_size);
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else
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printf("\t");
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if (type == BTRFS_FILE_EXTENT_REG ||
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type == BTRFS_FILE_EXTENT_PREALLOC)
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printf("%" PRIu64 "\t", logical_offset);
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else
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printf("\t");
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if (type == BTRFS_FILE_EXTENT_INLINE ||
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type == BTRFS_FILE_EXTENT_REG ||
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type == BTRFS_FILE_EXTENT_PREALLOC)
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printf("%" PRIu64 "\t", physical_size);
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else
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printf("\t");
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if (chunk) {
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uint64_t offset, stripe_nr, stripe_offset;
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size_t stripe_index, num_stripes;
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size_t i;
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offset = logical_offset - chunk->offset;
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stripe_nr = offset / chunk->stripe_len;
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stripe_offset = offset - stripe_nr * chunk->stripe_len;
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switch (chunk->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
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case 0:
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case BTRFS_BLOCK_GROUP_RAID0:
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stripe_index = stripe_nr % chunk->num_stripes;
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stripe_nr /= chunk->num_stripes;
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num_stripes = 1;
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break;
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case BTRFS_BLOCK_GROUP_RAID1:
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case BTRFS_BLOCK_GROUP_DUP:
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stripe_index = 0;
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num_stripes = chunk->num_stripes;
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break;
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case BTRFS_BLOCK_GROUP_RAID10: {
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size_t factor;
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factor = chunk->num_stripes / chunk->sub_stripes;
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stripe_index = (stripe_nr % factor *
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chunk->sub_stripes);
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stripe_nr /= factor;
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num_stripes = chunk->sub_stripes;
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break;
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}
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case BTRFS_BLOCK_GROUP_RAID5:
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case BTRFS_BLOCK_GROUP_RAID6: {
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size_t nr_parity_stripes, nr_data_stripes;
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if (chunk->type & BTRFS_BLOCK_GROUP_RAID6)
|
||||
nr_parity_stripes = 2;
|
||||
else
|
||||
nr_parity_stripes = 1;
|
||||
nr_data_stripes = (chunk->num_stripes -
|
||||
nr_parity_stripes);
|
||||
stripe_index = stripe_nr % nr_data_stripes;
|
||||
stripe_nr /= nr_data_stripes;
|
||||
stripe_index = ((stripe_nr + stripe_index) %
|
||||
chunk->num_stripes);
|
||||
num_stripes = 1;
|
||||
break;
|
||||
}
|
||||
default:
|
||||
num_stripes = 0;
|
||||
break;
|
||||
}
|
||||
|
||||
for (i = 0; i < num_stripes; i++) {
|
||||
if (i != 0)
|
||||
printf("\n\t\t\t\t\t\t\t");
|
||||
printf("%" PRIu64 "\t%" PRIu64,
|
||||
chunk->stripes[stripe_index].devid,
|
||||
chunk->stripes[stripe_index].offset +
|
||||
stripe_nr * chunk->stripe_len +
|
||||
stripe_offset);
|
||||
stripe_index++;
|
||||
}
|
||||
}
|
||||
printf("\n");
|
||||
|
||||
next:
|
||||
items_pos++;
|
||||
buf_off += sizeof(*header) + header->len;
|
||||
if (header->offset == UINT64_MAX)
|
||||
break;
|
||||
else
|
||||
search.key.min_offset = header->offset + 1;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
int main(int argc, char **argv)
|
||||
{
|
||||
struct option long_options[] = {
|
||||
{"help", no_argument, NULL, 'h'},
|
||||
};
|
||||
int fd, ret;
|
||||
struct chunk *chunks;
|
||||
size_t num_chunks, i;
|
||||
|
||||
if (argv[0])
|
||||
progname = argv[0];
|
||||
|
||||
for (;;) {
|
||||
int c;
|
||||
|
||||
c = getopt_long(argc, argv, "h", long_options, NULL);
|
||||
if (c == -1)
|
||||
break;
|
||||
|
||||
switch (c) {
|
||||
case 'h':
|
||||
usage(false);
|
||||
default:
|
||||
usage(true);
|
||||
}
|
||||
}
|
||||
if (optind != argc - 1)
|
||||
usage(true);
|
||||
|
||||
fd = open(argv[optind], O_RDONLY);
|
||||
if (fd == -1) {
|
||||
perror("open");
|
||||
return EXIT_FAILURE;
|
||||
}
|
||||
|
||||
ret = read_chunk_tree(fd, &chunks, &num_chunks);
|
||||
if (ret == -1)
|
||||
goto out;
|
||||
|
||||
ret = print_extents(fd, chunks, num_chunks);
|
||||
out:
|
||||
for (i = 0; i < num_chunks; i++)
|
||||
free(chunks[i].stripes);
|
||||
free(chunks);
|
||||
close(fd);
|
||||
return ret ? EXIT_FAILURE : EXIT_SUCCESS;
|
||||
}
|
||||
|
|
@ -7,7 +7,7 @@
|
|||
services.btrfs.autoScrub.interval = "weekly";
|
||||
|
||||
boot.resumeDevice = "/dev/mapper/ROOT";
|
||||
# boot.kernelParams = [ "resume_offset=[offset]" ];
|
||||
boot.kernelParams = [ "resume_offset=533760" ];
|
||||
# https://sawyershepherd.org/post/hibernating-to-an-encrypted-swapfile-on-btrfs-with-nixos/
|
||||
|
||||
disko.devices.disk.nvme0 = {
|
||||
|
|
|
|||
Loading…
Reference in a new issue