From 43c680e82e94061bf1b522466054730d8f3d8c22 Mon Sep 17 00:00:00 2001

From: Paolo Bonzini <pbonzini@redhat.com>

Date: Fri, 18 Oct 2013 08:14:42 +0200

Subject: [PATCH 17/81] qemu-img: add a "map" subcommand

RH-Author: Paolo Bonzini <pbonzini@redhat.com>

Message-id: <1382084091-16636-18-git-send-email-pbonzini@redhat.com>

Patchwork-id: 55000

O-Subject: [RHEL 7.0 qemu-kvm PATCH 17/26] qemu-img: add a "map" subcommand

Bugzilla: 989646

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

RH-Acked-by: Max Reitz <mreitz@redhat.com>

RH-Acked-by: Kevin Wolf <kwolf@redhat.com>

This command dumps the metadata of an entire chain, in either tabular or JSON

format.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

(cherry picked from commit 4c93a13b5daf9bd5fca1a547661b0fb9a2f0ca52)

---

 qemu-img-cmds.hx |   6 ++

 qemu-img.c       | 192 +++++++++++++++++++++++++++++++++++++++++++++++++++++++

 2 files changed, 198 insertions(+)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 qemu-img-cmds.hx |    6 ++

 qemu-img.c       |  192 ++++++++++++++++++++++++++++++++++++++++++++++++++++++

 2 files changed, 198 insertions(+), 0 deletions(-)

diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx

index 4ca7e95..c97a1f4 100644

--- a/qemu-img-cmds.hx

+++ b/qemu-img-cmds.hx

@@ -45,6 +45,12 @@ STEXI

 @item info [-f @var{fmt}] [--output=@var{ofmt}] [--backing-chain] @var{filename}

 ETEXI

+DEF("map", img_map,

+    "map [-f fmt] [--output=ofmt] filename")

+STEXI

+@item map [-f @var{fmt}] [--output=@var{ofmt}] @var{filename}

+ETEXI

+

 DEF("snapshot", img_snapshot,

     "snapshot [-q] [-l | -a snapshot | -c snapshot | -d snapshot] filename")

 STEXI

diff --git a/qemu-img.c b/qemu-img.c

index a9aabd5..e58c052 100644

--- a/qemu-img.c

+++ b/qemu-img.c

@@ -1919,6 +1919,198 @@ 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_close(bs);

+    bdrv_delete(bs);

+    return ret < 0;

+}

+

 #define SNAPSHOT_LIST   1

 #define SNAPSHOT_CREATE 2

 #define SNAPSHOT_APPLY  3

-- 

1.7.1