diff options
Diffstat (limited to 'qemu-img.c')
| -rw-r--r-- | qemu-img.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/qemu-img.c b/qemu-img.c index b074fa7912..3e5e388d1c 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -1801,6 +1801,197 @@ static int img_info(int argc, char **argv) return 0; } + +typedef struct MapEntry { + int flags; + int depth; + int64_t start; + int64_t length; + int64_t offset; + BlockDriverState *bs; +} MapEntry; + +static void dump_map_entry(OutputFormat output_format, MapEntry *e, + MapEntry *next) +{ + switch (output_format) { + case OFORMAT_HUMAN: + if ((e->flags & BDRV_BLOCK_DATA) && + !(e->flags & BDRV_BLOCK_OFFSET_VALID)) { + error_report("File contains external, encrypted or compressed clusters."); + exit(1); + } + if ((e->flags & (BDRV_BLOCK_DATA|BDRV_BLOCK_ZERO)) == BDRV_BLOCK_DATA) { + printf("%#-16"PRIx64"%#-16"PRIx64"%#-16"PRIx64"%s\n", + e->start, e->length, e->offset, e->bs->filename); + } + /* This format ignores the distinction between 0, ZERO and ZERO|DATA. + * Modify the flags here to allow more coalescing. + */ + if (next && + (next->flags & (BDRV_BLOCK_DATA|BDRV_BLOCK_ZERO)) != BDRV_BLOCK_DATA) { + next->flags &= ~BDRV_BLOCK_DATA; + next->flags |= BDRV_BLOCK_ZERO; + } + break; + case OFORMAT_JSON: + printf("%s{ \"start\": %"PRId64", \"length\": %"PRId64", \"depth\": %d," + " \"zero\": %s, \"data\": %s", + (e->start == 0 ? "[" : ",\n"), + e->start, e->length, e->depth, + (e->flags & BDRV_BLOCK_ZERO) ? "true" : "false", + (e->flags & BDRV_BLOCK_DATA) ? "true" : "false"); + if (e->flags & BDRV_BLOCK_OFFSET_VALID) { + printf(", 'offset': %"PRId64"", e->offset); + } + putchar('}'); + + if (!next) { + printf("]\n"); + } + break; + } +} + +static int get_block_status(BlockDriverState *bs, int64_t sector_num, + int nb_sectors, MapEntry *e) +{ + int64_t ret; + int depth; + + /* As an optimization, we could cache the current range of unallocated + * clusters in each file of the chain, and avoid querying the same + * range repeatedly. + */ + + depth = 0; + for (;;) { + ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &nb_sectors); + if (ret < 0) { + return ret; + } + assert(nb_sectors); + if (ret & (BDRV_BLOCK_ZERO|BDRV_BLOCK_DATA)) { + break; + } + bs = bs->backing_hd; + if (bs == NULL) { + ret = 0; + break; + } + + depth++; + } + + e->start = sector_num * BDRV_SECTOR_SIZE; + e->length = nb_sectors * BDRV_SECTOR_SIZE; + e->flags = ret & ~BDRV_BLOCK_OFFSET_MASK; + e->offset = ret & BDRV_BLOCK_OFFSET_MASK; + e->depth = depth; + e->bs = bs; + return 0; +} + +static int img_map(int argc, char **argv) +{ + int c; + OutputFormat output_format = OFORMAT_HUMAN; + BlockDriverState *bs; + const char *filename, *fmt, *output; + int64_t length; + MapEntry curr = { .length = 0 }, next; + int ret = 0; + + fmt = NULL; + output = NULL; + for (;;) { + int option_index = 0; + static const struct option long_options[] = { + {"help", no_argument, 0, 'h'}, + {"format", required_argument, 0, 'f'}, + {"output", required_argument, 0, OPTION_OUTPUT}, + {0, 0, 0, 0} + }; + c = getopt_long(argc, argv, "f:h", + long_options, &option_index); + if (c == -1) { + break; + } + switch (c) { + case '?': + case 'h': + help(); + break; + case 'f': + fmt = optarg; + break; + case OPTION_OUTPUT: + output = optarg; + break; + } + } + if (optind >= argc) { + help(); + } + filename = argv[optind++]; + + if (output && !strcmp(output, "json")) { + output_format = OFORMAT_JSON; + } else if (output && !strcmp(output, "human")) { + output_format = OFORMAT_HUMAN; + } else if (output) { + error_report("--output must be used with human or json as argument."); + return 1; + } + + bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS, true, false); + if (!bs) { + return 1; + } + + if (output_format == OFORMAT_HUMAN) { + printf("%-16s%-16s%-16s%s\n", "Offset", "Length", "Mapped to", "File"); + } + + length = bdrv_getlength(bs); + while (curr.start + curr.length < length) { + int64_t nsectors_left; + int64_t sector_num; + int n; + + sector_num = (curr.start + curr.length) >> BDRV_SECTOR_BITS; + + /* Probe up to 1 GiB at a time. */ + nsectors_left = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE) - sector_num; + n = MIN(1 << (30 - BDRV_SECTOR_BITS), nsectors_left); + ret = get_block_status(bs, sector_num, n, &next); + + if (ret < 0) { + error_report("Could not read file metadata: %s", strerror(-ret)); + goto out; + } + + if (curr.length != 0 && curr.flags == next.flags && + curr.depth == next.depth && + ((curr.flags & BDRV_BLOCK_OFFSET_VALID) == 0 || + curr.offset + curr.length == next.offset)) { + curr.length += next.length; + continue; + } + + if (curr.length > 0) { + dump_map_entry(output_format, &curr, &next); + } + curr = next; + } + + dump_map_entry(output_format, &curr, NULL); + +out: + bdrv_unref(bs); + return ret < 0; +} + #define SNAPSHOT_LIST 1 #define SNAPSHOT_CREATE 2 #define SNAPSHOT_APPLY 3 |