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Re: [RFC 2/4] qcow2: add configurations for zoned format extension


From: Sam Li
Subject: Re: [RFC 2/4] qcow2: add configurations for zoned format extension
Date: Mon, 19 Jun 2023 18:32:52 +0800

Stefan Hajnoczi <stefanha@redhat.com> 于2023年6月19日周一 18:10写道:
>
> On Mon, Jun 05, 2023 at 06:41:06PM +0800, Sam Li wrote:
> > To configure the zoned format feature on the qcow2 driver, it
> > requires following arguments: the device size, zoned profile,
> > zoned model, zone size, zone capacity, number of conventional
> > zones, limits on zone resources (max append sectors, max open
> > zones, and max_active_zones).
> >
> > To create a qcow2 file with zoned format, use command like this:
> > $ qemu-img create -f qcow2 test.qcow2 -o size=768M -o
> > zone_size=64M -o zone_capacity=64M -o zone_nr_conv=0 -o
> > max_append_sectors=512 -o max_open_zones=0 -o max_active_zones=0
> >  -o zoned_profile=zbc
> >
> > Signed-off-by: Sam Li <faithilikerun@gmail.com>
> > ---
> >  block/qcow2.c                    | 119 +++++++++++++++++++++++++++++++
> >  block/qcow2.h                    |  21 ++++++
> >  include/block/block-common.h     |   5 ++
> >  include/block/block_int-common.h |   8 +++
> >  qapi/block-core.json             |  46 ++++++++----
> >  5 files changed, 185 insertions(+), 14 deletions(-)
> >
> > diff --git a/block/qcow2.c b/block/qcow2.c
> > index 7f3948360d..b886dab42b 100644
> > --- a/block/qcow2.c
> > +++ b/block/qcow2.c
> > @@ -73,6 +73,7 @@ typedef struct {
> >  #define  QCOW2_EXT_MAGIC_CRYPTO_HEADER 0x0537be77
> >  #define  QCOW2_EXT_MAGIC_BITMAPS 0x23852875
> >  #define  QCOW2_EXT_MAGIC_DATA_FILE 0x44415441
> > +#define  QCOW2_EXT_MAGIC_ZONED_FORMAT 0x7a6264
> >
> >  static int coroutine_fn
> >  qcow2_co_preadv_compressed(BlockDriverState *bs,
> > @@ -210,6 +211,7 @@ qcow2_read_extensions(BlockDriverState *bs, uint64_t 
> > start_offset,
> >      uint64_t offset;
> >      int ret;
> >      Qcow2BitmapHeaderExt bitmaps_ext;
> > +    Qcow2ZonedHeaderExtension zoned_ext;
> >
> >      if (need_update_header != NULL) {
> >          *need_update_header = false;
> > @@ -431,6 +433,37 @@ qcow2_read_extensions(BlockDriverState *bs, uint64_t 
> > start_offset,
> >              break;
> >          }
> >
> > +        case QCOW2_EXT_MAGIC_ZONED_FORMAT:
> > +        {
> > +            if (ext.len != sizeof(zoned_ext)) {
> > +                error_setg_errno(errp, -ret, "zoned_ext: "
> > +                                             "Invalid extension length");
> > +                return -EINVAL;
> > +            }
> > +            ret = bdrv_pread(bs->file, offset, ext.len, &zoned_ext, 0);
> > +            if (ret < 0) {
> > +                error_setg_errno(errp, -ret, "zoned_ext: "
> > +                                             "Could not read ext header");
> > +                return ret;
> > +            }
> > +
> > +            zoned_ext.zone_size = be32_to_cpu(zoned_ext.zone_size);
> > +            zoned_ext.nr_zones = be32_to_cpu(zoned_ext.nr_zones);
> > +            zoned_ext.zone_nr_conv = be32_to_cpu(zoned_ext.zone_nr_conv);
> > +            zoned_ext.max_open_zones = 
> > be32_to_cpu(zoned_ext.max_open_zones);
> > +            zoned_ext.max_active_zones =
> > +                be32_to_cpu(zoned_ext.max_active_zones);
> > +            zoned_ext.max_append_sectors =
> > +                be32_to_cpu(zoned_ext.max_append_sectors);
> > +            s->zoned_header = zoned_ext;
>
> Please validate these values. The image file is not trusted and may be
> broken/corrupt. For example, zone_size=0 and nr_zones=0 must be rejected
> because the code can't do anything useful when these values are zero
> (similar for values that are not multiples of the block size).
>
> > +
> > +#ifdef DEBUG_EXT
> > +            printf("Qcow2: Got zoned format extension: "
> > +                   "offset=%" PRIu32 "\n", offset);
> > +#endif
> > +            break;
> > +        }
> > +
> >          default:
> >              /* unknown magic - save it in case we need to rewrite the 
> > header */
> >              /* If you add a new feature, make sure to also update the fast
> > @@ -3071,6 +3104,31 @@ int qcow2_update_header(BlockDriverState *bs)
> >          buflen -= ret;
> >      }
> >
> > +    /* Zoned devices header extension */
> > +    if (s->zoned_header.zoned == BLK_Z_HM) {
> > +        Qcow2ZonedHeaderExtension zoned_header = {
> > +            .zoned_profile      = s->zoned_header.zoned_profile,
> > +            .zoned              = s->zoned_header.zoned,
> > +            .nr_zones           = cpu_to_be32(s->zoned_header.nr_zones),
> > +            .zone_size          = cpu_to_be32(s->zoned_header.zone_size),
> > +            .zone_capacity      = 
> > cpu_to_be32(s->zoned_header.zone_capacity),
> > +            .zone_nr_conv       = 
> > cpu_to_be32(s->zoned_header.zone_nr_conv),
> > +            .max_open_zones     = 
> > cpu_to_be32(s->zoned_header.max_open_zones),
> > +            .max_active_zones   =
> > +                cpu_to_be32(s->zoned_header.max_active_zones),
> > +            .max_append_sectors =
> > +                cpu_to_be32(s->zoned_header.max_append_sectors)
> > +        };
> > +        ret = header_ext_add(buf, QCOW2_EXT_MAGIC_ZONED_FORMAT,
> > +                             &zoned_header, sizeof(zoned_header),
> > +                             buflen);
> > +        if (ret < 0) {
> > +            goto fail;
> > +        }
> > +        buf += ret;
> > +        buflen -= ret;
> > +    }
> > +
> >      /* Keep unknown header extensions */
> >      QLIST_FOREACH(uext, &s->unknown_header_ext, next) {
> >          ret = header_ext_add(buf, uext->magic, uext->data, uext->len, 
> > buflen);
> > @@ -3755,6 +3813,18 @@ qcow2_co_create(BlockdevCreateOptions 
> > *create_options, Error **errp)
> >          s->image_data_file = g_strdup(data_bs->filename);
> >      }
> >
> > +    if (!strcmp(qcow2_opts->zoned_profile, "zbc")) {
> > +        BDRVQcow2State *s = blk_bs(blk)->opaque;
> > +        s->zoned_header.zoned_profile = BLK_ZP_ZBC;
> > +        s->zoned_header.zoned = BLK_Z_HM;
> > +        s->zoned_header.zone_size = qcow2_opts->zone_size;
> > +        s->zoned_header.zone_capacity = qcow2_opts->zone_capacity;
> > +        s->zoned_header.zone_nr_conv = qcow2_opts->zone_nr_conv;
> > +        s->zoned_header.max_open_zones = qcow2_opts->max_open_zones;
> > +        s->zoned_header.max_active_zones = qcow2_opts->max_active_zones;
> > +        s->zoned_header.max_append_sectors = 
> > qcow2_opts->max_append_sectors;
>
> Where is the presence of these optional qcow2_opts checked? For example,
> if the user didn't specify zone_size, then they cannot create an image
> with a zoned profile.
>
> These options also need to be validated to ensure that they contain
> reasonable values (e.g. not 0).
>
> > +    }
> > +
> >      /* Create a full header (including things like feature table) */
> >      ret = qcow2_update_header(blk_bs(blk));
> >      bdrv_graph_co_rdunlock();
> > @@ -3873,6 +3943,13 @@ qcow2_co_create_opts(BlockDriver *drv, const char 
> > *filename, QemuOpts *opts,
> >          qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v3");
> >      }
> >
> > +    /* The available zoned-profile options are zbc, which stands for
> > +     * ZBC/ZAC standards, and zns following NVMe ZNS spec. */
> > +    val = qdict_get_try_str(qdict, BLOCK_OPT_Z_PROFILE);
> > +    if (val) {
> > +        qdict_put_str(qdict, BLOCK_OPT_Z_PROFILE, val);
> > +    }
>
> What is the purpose of this code, it fetches and replaces the same qdict
> element?

It creates a string configuration for zoned_profile and matches the
user input to that config.

>
> > +
> >      /* Change legacy command line options into QMP ones */
> >      static const QDictRenames opt_renames[] = {
> >          { BLOCK_OPT_BACKING_FILE,       "backing-file" },
> > @@ -3885,6 +3962,13 @@ qcow2_co_create_opts(BlockDriver *drv, const char 
> > *filename, QemuOpts *opts,
> >          { BLOCK_OPT_COMPAT_LEVEL,       "version" },
> >          { BLOCK_OPT_DATA_FILE_RAW,      "data-file-raw" },
> >          { BLOCK_OPT_COMPRESSION_TYPE,   "compression-type" },
> > +        { BLOCK_OPT_Z_PROFILE,          "zoned-profile"},
> > +        { BLOCK_OPT_Z_NR_COV,           "zone-nr-conv"},
> > +        { BLOCK_OPT_Z_MOZ,              "max-open-zones"},
> > +        { BLOCK_OPT_Z_MAZ,              "max-active-zones"},
> > +        { BLOCK_OPT_Z_MAS,              "max-append-sectors"},
> > +        { BLOCK_OPT_Z_SIZE,             "zone-size"},
> > +        { BLOCK_OPT_Z_CAP,              "zone-capacity"},
> >          { NULL, NULL },
> >      };
> >
> > @@ -6048,6 +6132,41 @@ static QemuOptsList qcow2_create_opts = {
> >              .help = "Compression method used for image cluster "        \
> >                      "compression",                                      \
> >              .def_value_str = "zlib"                                     \
> > +        },                                                              \
> > +            {
>
> The forward slash ('\') that wraps the line is missing and indentation
> is off.
>
> > +            .name = BLOCK_OPT_Z_PROFILE,                                \
> > +            .type = QEMU_OPT_STRING,                                    \
> > +            .help = "zoned format option for the disk img",             \
> > +        },                                                              \
> > +            {                                                           \
>
> Indentation is off.
>
> > +            .name = BLOCK_OPT_Z_SIZE,                                   \
> > +            .type = QEMU_OPT_SIZE,                                      \
> > +            .help = "zone size",                                        \
> > +        },                                                              \
> > +        {                                                           \
> > +            .name = BLOCK_OPT_Z_CAP,                                    \
> > +            .type = QEMU_OPT_SIZE,                                      \
> > +            .help = "zone capacity",                                    \
> > +        },                                                              \
> > +        {                                                               \
> > +                .name = BLOCK_OPT_Z_NR_COV,                             \
>
> Indentation is off.
>
> > +                .type = QEMU_OPT_NUMBER,                                \
> > +                .help = "numbers of conventional zones",                \
> > +        },                                                              \
> > +        {                                                               \
> > +                .name = BLOCK_OPT_Z_MAS,                                \
> > +                .type = QEMU_OPT_NUMBER,                                \
> > +                .help = "max append sectors",                           \
> > +        },                                                              \
> > +        {                                                               \
> > +                .name = BLOCK_OPT_Z_MAZ,                                \
> > +                .type = QEMU_OPT_NUMBER,                                \
> > +                .help = "max active zones",                             \
> > +        },                                                              \
> > +        {                                                               \
> > +                .name = BLOCK_OPT_Z_MOZ,                                \
> > +                .type = QEMU_OPT_NUMBER,                                \
> > +                .help = "max open zones",                               \
> >          },
> >          QCOW_COMMON_OPTIONS,
> >          { /* end of list */ }
> > diff --git a/block/qcow2.h b/block/qcow2.h
> > index 4f67eb912a..fe18dc4d97 100644
> > --- a/block/qcow2.h
> > +++ b/block/qcow2.h
> > @@ -235,6 +235,20 @@ typedef struct Qcow2CryptoHeaderExtension {
> >      uint64_t length;
> >  } QEMU_PACKED Qcow2CryptoHeaderExtension;
> >
> > +typedef struct Qcow2ZonedHeaderExtension {
> > +    /* Zoned device attributes */
> > +    BlockZonedProfile zoned_profile;
> > +    BlockZoneModel zoned;
> > +    uint32_t zone_size;
> > +    uint32_t zone_capacity;
> > +    uint32_t nr_zones;
> > +    uint32_t zone_nr_conv;
> > +    uint32_t max_active_zones;
> > +    uint32_t max_open_zones;
> > +    uint32_t max_append_sectors;
> > +    uint8_t padding[3];
>
> This looks strange. Why is there 3 bytes of padding at the end? Normally
> padding would align to an even power-of-two number of bytes like 2, 4,
> 8, etc.

It is calculated as 3 if sizeof(zoned+zoned_profile) = 8. Else if it's
16, the padding is 2.

>
> > +} QEMU_PACKED Qcow2ZonedHeaderExtension;
> > +
> >  typedef struct Qcow2UnknownHeaderExtension {
> >      uint32_t magic;
> >      uint32_t len;
> > @@ -419,6 +433,13 @@ typedef struct BDRVQcow2State {
> >       * is to convert the image with the desired compression type set.
> >       */
> >      Qcow2CompressionType compression_type;
> > +
> > +    /* States of zoned device */
> > +    Qcow2ZonedHeaderExtension zoned_header;
> > +    uint32_t nr_zones_exp_open;
> > +    uint32_t nr_zones_imp_open;
> > +    uint32_t nr_zones_closed;
> > +    BlockZoneWps *wps;
>
> Normally qcow2 code passes bs around, so it should be possible to access
> the wps pointer without duplicating it here. This new field is not used
> in this patch, so I can't tell yet how important it is. It's safer to
> avoid duplicating pointers when the original pointer can be accessed
> conveniently so that use-after-free, double-free, and similar memory
> management bugs can be eliminated.

I see. Thanks!

>
> >  } BDRVQcow2State;
> >
> >  typedef struct Qcow2COWRegion {
> > diff --git a/include/block/block-common.h b/include/block/block-common.h
> > index e15395f2cb..9f04a772f6 100644
> > --- a/include/block/block-common.h
> > +++ b/include/block/block-common.h
> > @@ -108,6 +108,11 @@ typedef enum BlockZoneType {
> >      BLK_ZT_SWP = 0x3, /* Sequential writes preferred */
> >  } BlockZoneType;
> >
> > +typedef enum BlockZonedProfile {
> > +    BLK_ZP_ZBC = 0x1,
> > +    BLK_ZP_ZNS = 0x2,
> > +} BlockZonedProfile;
> > +
> >  /*
> >   * Zone descriptor data structure.
> >   * Provides information on a zone with all position and size values in 
> > bytes.
> > diff --git a/include/block/block_int-common.h 
> > b/include/block/block_int-common.h
> > index 74195c3004..4be35feaf8 100644
> > --- a/include/block/block_int-common.h
> > +++ b/include/block/block_int-common.h
> > @@ -57,6 +57,14 @@
> >  #define BLOCK_OPT_DATA_FILE_RAW     "data_file_raw"
> >  #define BLOCK_OPT_COMPRESSION_TYPE  "compression_type"
> >  #define BLOCK_OPT_EXTL2             "extended_l2"
> > +#define BLOCK_OPT_Z_PROFILE         "zoned_profile"
> > +#define BLOCK_OPT_Z_MODEL           "zoned"
> > +#define BLOCK_OPT_Z_SIZE            "zone_size"
> > +#define BLOCK_OPT_Z_CAP             "zone_capacity"
> > +#define BLOCK_OPT_Z_NR_COV          "zone_nr_conv"
> > +#define BLOCK_OPT_Z_MAS             "max_append_sectors"
> > +#define BLOCK_OPT_Z_MAZ             "max_active_zones"
> > +#define BLOCK_OPT_Z_MOZ             "max_open_zones"
> >
> >  #define BLOCK_PROBE_BUF_SIZE        512
> >
> > diff --git a/qapi/block-core.json b/qapi/block-core.json
> > index 4bf89171c6..f9a584cbb3 100644
> > --- a/qapi/block-core.json
> > +++ b/qapi/block-core.json
> > @@ -5013,24 +5013,42 @@
> >  #
> >  # @compression-type: The image cluster compression method
> >  #     (default: zlib, since 5.1)
> > +# @zoned-profile: Two zoned device protocol options, zbc or zns
> > +#                 (default: off, since 8.0)
> > +# @zone-size: The size of a zone of the zoned device (since 8.0)
> > +# @zone-capacity: The capacity of a zone of the zoned device (since 8.0)
> > +# @zone-nr-conv: The number of conventional zones of the zoned device
> > +#                (since 8.0)
> > +# @max-open-zones: The maximal allowed open zones (since 8.0)
> > +# @max-active-zones: The limit of the zones that have the implicit open,
> > +#                    explicit open or closed state (since 8.0)
> > +# @max-append-sectors: The maximal sectors that is allowed to append write
> > +#                      (since 8.0)
>
> Since 8.1.
>
> >  #
> >  # Since: 2.12
> >  ##
> >  { 'struct': 'BlockdevCreateOptionsQcow2',
> > -  'data': { 'file':             'BlockdevRef',
> > -            '*data-file':       'BlockdevRef',
> > -            '*data-file-raw':   'bool',
> > -            '*extended-l2':     'bool',
> > -            'size':             'size',
> > -            '*version':         'BlockdevQcow2Version',
> > -            '*backing-file':    'str',
> > -            '*backing-fmt':     'BlockdevDriver',
> > -            '*encrypt':         'QCryptoBlockCreateOptions',
> > -            '*cluster-size':    'size',
> > -            '*preallocation':   'PreallocMode',
> > -            '*lazy-refcounts':  'bool',
> > -            '*refcount-bits':   'int',
> > -            '*compression-type':'Qcow2CompressionType' } }
> > +  'data': { 'file':                'BlockdevRef',
> > +            '*data-file':          'BlockdevRef',
> > +            '*data-file-raw':      'bool',
> > +            '*extended-l2':        'bool',
> > +            'size':                'size',
> > +            '*version':            'BlockdevQcow2Version',
> > +            '*backing-file':       'str',
> > +            '*backing-fmt':        'BlockdevDriver',
> > +            '*encrypt':            'QCryptoBlockCreateOptions',
> > +            '*cluster-size':       'size',
> > +            '*preallocation':      'PreallocMode',
> > +            '*lazy-refcounts':     'bool',
> > +            '*refcount-bits':      'int',
> > +            '*compression-type':   'Qcow2CompressionType',
> > +            '*zoned-profile':      'str',
> > +            '*zone-size':          'size',
> > +            '*zone-capacity':      'size',
> > +            '*zone-nr-conv':       'uint32',
> > +            '*max-open-zones':     'uint32',
> > +            '*max-active-zones':   'uint32',
> > +            '*max-append-sectors': 'uint32'}}
> >
> >  ##
> >  # @BlockdevCreateOptionsQed:
> > --
> > 2.40.1
> >



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