diff options
Diffstat (limited to 'nbd')
| -rw-r--r-- | nbd/server.c | 278 | ||||
| -rw-r--r-- | nbd/trace-events | 1 |
2 files changed, 256 insertions, 23 deletions
diff --git a/nbd/server.c b/nbd/server.c index 9171cd4168..2c2d62c636 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -23,6 +23,13 @@ #include "nbd-internal.h" #define NBD_META_ID_BASE_ALLOCATION 0 +#define NBD_META_ID_DIRTY_BITMAP 1 + +/* NBD_MAX_BITMAP_EXTENTS: 1 mb of extents data. An empirical + * constant. If an increase is needed, note that the NBD protocol + * recommends no larger than 32 mb, so that the client won't consider + * the reply as a denial of service attack. */ +#define NBD_MAX_BITMAP_EXTENTS (0x100000 / 8) static int system_errno_to_nbd_errno(int err) { @@ -80,6 +87,9 @@ struct NBDExport { BlockBackend *eject_notifier_blk; Notifier eject_notifier; + + BdrvDirtyBitmap *export_bitmap; + char *export_bitmap_context; }; static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); @@ -92,6 +102,7 @@ typedef struct NBDExportMetaContexts { bool valid; /* means that negotiation of the option finished without errors */ bool base_allocation; /* export base:allocation context (block status) */ + bool bitmap; /* export qemu:dirty-bitmap:<export bitmap name> */ } NBDExportMetaContexts; struct NBDClient { @@ -814,6 +825,56 @@ static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta, &meta->base_allocation, errp); } +/* nbd_meta_bitmap_query + * + * Handle query to 'qemu:' namespace. + * @len is the amount of text remaining to be read from the current name, after + * the 'qemu:' portion has been stripped. + * + * Return -errno on I/O error, 0 if option was completely handled by + * sending a reply about inconsistent lengths, or 1 on success. */ +static int nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta, + uint32_t len, Error **errp) +{ + bool dirty_bitmap = false; + size_t dirty_bitmap_len = strlen("dirty-bitmap:"); + int ret; + + if (!meta->exp->export_bitmap) { + trace_nbd_negotiate_meta_query_skip("no dirty-bitmap exported"); + return nbd_opt_skip(client, len, errp); + } + + if (len == 0) { + if (client->opt == NBD_OPT_LIST_META_CONTEXT) { + meta->bitmap = true; + } + trace_nbd_negotiate_meta_query_parse("empty"); + return 1; + } + + if (len < dirty_bitmap_len) { + trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:"); + return nbd_opt_skip(client, len, errp); + } + + len -= dirty_bitmap_len; + ret = nbd_meta_pattern(client, "dirty-bitmap:", &dirty_bitmap, errp); + if (ret <= 0) { + return ret; + } + if (!dirty_bitmap) { + trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:"); + return nbd_opt_skip(client, len, errp); + } + + trace_nbd_negotiate_meta_query_parse("dirty-bitmap:"); + + return nbd_meta_empty_or_pattern( + client, meta->exp->export_bitmap_context + + strlen("qemu:dirty_bitmap:"), len, &meta->bitmap, errp); +} + /* nbd_negotiate_meta_query * * Parse namespace name and call corresponding function to parse body of the @@ -829,9 +890,14 @@ static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta, static int nbd_negotiate_meta_query(NBDClient *client, NBDExportMetaContexts *meta, Error **errp) { + /* + * Both 'qemu' and 'base' namespaces have length = 5 including a + * colon. If another length namespace is later introduced, this + * should certainly be refactored. + */ int ret; - char query[sizeof("base:") - 1]; - size_t baselen = strlen("base:"); + size_t ns_len = 5; + char ns[5]; uint32_t len; ret = nbd_opt_read(client, &len, sizeof(len), errp); @@ -840,25 +906,27 @@ static int nbd_negotiate_meta_query(NBDClient *client, } cpu_to_be32s(&len); - /* The only supported namespace for now is 'base'. So query should start - * with 'base:'. Otherwise, we can ignore it and skip the remainder. */ - if (len < baselen) { + if (len < ns_len) { trace_nbd_negotiate_meta_query_skip("length too short"); return nbd_opt_skip(client, len, errp); } - len -= baselen; - ret = nbd_opt_read(client, query, baselen, errp); + len -= ns_len; + ret = nbd_opt_read(client, ns, ns_len, errp); if (ret <= 0) { return ret; } - if (strncmp(query, "base:", baselen) != 0) { - trace_nbd_negotiate_meta_query_skip("not for base: namespace"); - return nbd_opt_skip(client, len, errp); + + if (!strncmp(ns, "base:", ns_len)) { + trace_nbd_negotiate_meta_query_parse("base:"); + return nbd_meta_base_query(client, meta, len, errp); + } else if (!strncmp(ns, "qemu:", ns_len)) { + trace_nbd_negotiate_meta_query_parse("qemu:"); + return nbd_meta_qemu_query(client, meta, len, errp); } - trace_nbd_negotiate_meta_query_parse("base:"); - return nbd_meta_base_query(client, meta, len, errp); + trace_nbd_negotiate_meta_query_skip("unknown namespace"); + return nbd_opt_skip(client, len, errp); } /* nbd_negotiate_meta_queries @@ -928,6 +996,16 @@ static int nbd_negotiate_meta_queries(NBDClient *client, } } + if (meta->bitmap) { + ret = nbd_negotiate_send_meta_context(client, + meta->exp->export_bitmap_context, + NBD_META_ID_DIRTY_BITMAP, + errp); + if (ret < 0) { + return ret; + } + } + ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); if (ret == 0) { meta->valid = true; @@ -1556,6 +1634,11 @@ void nbd_export_put(NBDExport *exp) exp->blk = NULL; } + if (exp->export_bitmap) { + bdrv_dirty_bitmap_set_qmp_locked(exp->export_bitmap, false); + g_free(exp->export_bitmap_context); + } + g_free(exp); } } @@ -1797,9 +1880,15 @@ static int blockstatus_to_extent_be(BlockDriverState *bs, uint64_t offset, } /* nbd_co_send_extents - * @extents should be in big-endian */ + * + * @length is only for tracing purposes (and may be smaller or larger + * than the client's original request). @last controls whether + * NBD_REPLY_FLAG_DONE is sent. @extents should already be in + * big-endian format. + */ static int nbd_co_send_extents(NBDClient *client, uint64_t handle, - NBDExtent *extents, unsigned nb_extents, + NBDExtent *extents, unsigned int nb_extents, + uint64_t length, bool last, uint32_t context_id, Error **errp) { NBDStructuredMeta chunk; @@ -1809,7 +1898,9 @@ static int nbd_co_send_extents(NBDClient *client, uint64_t handle, {.iov_base = extents, .iov_len = nb_extents * sizeof(extents[0])} }; - set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_BLOCK_STATUS, + trace_nbd_co_send_extents(handle, nb_extents, context_id, length, last); + set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0, + NBD_REPLY_TYPE_BLOCK_STATUS, handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); stl_be_p(&chunk.context_id, context_id); @@ -1819,8 +1910,8 @@ static int nbd_co_send_extents(NBDClient *client, uint64_t handle, /* Get block status from the exported device and send it to the client */ static int nbd_co_send_block_status(NBDClient *client, uint64_t handle, BlockDriverState *bs, uint64_t offset, - uint64_t length, uint32_t context_id, - Error **errp) + uint64_t length, bool last, + uint32_t context_id, Error **errp) { int ret; NBDExtent extent; @@ -1831,7 +1922,84 @@ static int nbd_co_send_block_status(NBDClient *client, uint64_t handle, client, handle, -ret, "can't get block status", errp); } - return nbd_co_send_extents(client, handle, &extent, 1, context_id, errp); + return nbd_co_send_extents(client, handle, &extent, 1, length, last, + context_id, errp); +} + +/* + * Populate @extents from a dirty bitmap. Unless @dont_fragment, the + * final extent may exceed the original @length. Store in @length the + * byte length encoded (which may be smaller or larger than the + * original), and return the number of extents used. + */ +static unsigned int bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset, + uint64_t *length, NBDExtent *extents, + unsigned int nb_extents, + bool dont_fragment) +{ + uint64_t begin = offset, end; + uint64_t overall_end = offset + *length; + unsigned int i = 0; + BdrvDirtyBitmapIter *it; + bool dirty; + + bdrv_dirty_bitmap_lock(bitmap); + + it = bdrv_dirty_iter_new(bitmap); + dirty = bdrv_get_dirty_locked(NULL, bitmap, offset); + + assert(begin < overall_end && nb_extents); + while (begin < overall_end && i < nb_extents) { + if (dirty) { + end = bdrv_dirty_bitmap_next_zero(bitmap, begin); + } else { + bdrv_set_dirty_iter(it, begin); + end = bdrv_dirty_iter_next(it); + } + if (end == -1 || end - begin > UINT32_MAX) { + /* Cap to an aligned value < 4G beyond begin. */ + end = MIN(bdrv_dirty_bitmap_size(bitmap), + begin + UINT32_MAX + 1 - + bdrv_dirty_bitmap_granularity(bitmap)); + } + if (dont_fragment && end > overall_end) { + end = overall_end; + } + + extents[i].length = cpu_to_be32(end - begin); + extents[i].flags = cpu_to_be32(dirty ? NBD_STATE_DIRTY : 0); + i++; + begin = end; + dirty = !dirty; + } + + bdrv_dirty_iter_free(it); + + bdrv_dirty_bitmap_unlock(bitmap); + + *length = end - offset; + return i; +} + +static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle, + BdrvDirtyBitmap *bitmap, uint64_t offset, + uint32_t length, bool dont_fragment, bool last, + uint32_t context_id, Error **errp) +{ + int ret; + unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS; + NBDExtent *extents = g_new(NBDExtent, nb_extents); + uint64_t final_length = length; + + nb_extents = bitmap_to_extents(bitmap, offset, &final_length, extents, + nb_extents, dont_fragment); + + ret = nbd_co_send_extents(client, handle, extents, nb_extents, + final_length, last, context_id, errp); + + g_free(extents); + + return ret; } /* nbd_co_receive_request @@ -2051,11 +2219,34 @@ static coroutine_fn int nbd_handle_request(NBDClient *client, return nbd_send_generic_reply(client, request->handle, -EINVAL, "need non-zero length", errp); } - if (client->export_meta.valid && client->export_meta.base_allocation) { - return nbd_co_send_block_status(client, request->handle, - blk_bs(exp->blk), request->from, - request->len, - NBD_META_ID_BASE_ALLOCATION, errp); + if (client->export_meta.valid && + (client->export_meta.base_allocation || + client->export_meta.bitmap)) + { + if (client->export_meta.base_allocation) { + ret = nbd_co_send_block_status(client, request->handle, + blk_bs(exp->blk), request->from, + request->len, + !client->export_meta.bitmap, + NBD_META_ID_BASE_ALLOCATION, + errp); + if (ret < 0) { + return ret; + } + } + + if (client->export_meta.bitmap) { + ret = nbd_co_send_bitmap(client, request->handle, + client->exp->export_bitmap, + request->from, request->len, + request->flags & NBD_CMD_FLAG_REQ_ONE, + true, NBD_META_ID_DIRTY_BITMAP, errp); + if (ret < 0) { + return ret; + } + } + + return ret; } else { return nbd_send_generic_reply(client, request->handle, -EINVAL, "CMD_BLOCK_STATUS not negotiated", @@ -2207,3 +2398,44 @@ void nbd_client_new(NBDExport *exp, co = qemu_coroutine_create(nbd_co_client_start, client); qemu_coroutine_enter(co); } + +void nbd_export_bitmap(NBDExport *exp, const char *bitmap, + const char *bitmap_export_name, Error **errp) +{ + BdrvDirtyBitmap *bm = NULL; + BlockDriverState *bs = blk_bs(exp->blk); + + if (exp->export_bitmap) { + error_setg(errp, "Export bitmap is already set"); + return; + } + + while (true) { + bm = bdrv_find_dirty_bitmap(bs, bitmap); + if (bm != NULL || bs->backing == NULL) { + break; + } + + bs = bs->backing->bs; + } + + if (bm == NULL) { + error_setg(errp, "Bitmap '%s' is not found", bitmap); + return; + } + + if (bdrv_dirty_bitmap_enabled(bm)) { + error_setg(errp, "Bitmap '%s' is enabled", bitmap); + return; + } + + if (bdrv_dirty_bitmap_qmp_locked(bm)) { + error_setg(errp, "Bitmap '%s' is locked", bitmap); + return; + } + + bdrv_dirty_bitmap_set_qmp_locked(bm, true); + exp->export_bitmap = bm; + exp->export_bitmap_context = + g_strdup_printf("qemu:dirty-bitmap:%s", bitmap_export_name); +} diff --git a/nbd/trace-events b/nbd/trace-events index dee081e775..5e1d4afe8e 100644 --- a/nbd/trace-events +++ b/nbd/trace-events @@ -64,6 +64,7 @@ nbd_co_send_simple_reply(uint64_t handle, uint32_t error, const char *errname, i nbd_co_send_structured_done(uint64_t handle) "Send structured reply done: handle = %" PRIu64 nbd_co_send_structured_read(uint64_t handle, uint64_t offset, void *data, size_t size) "Send structured read data reply: handle = %" PRIu64 ", offset = %" PRIu64 ", data = %p, len = %zu" nbd_co_send_structured_read_hole(uint64_t handle, uint64_t offset, size_t size) "Send structured read hole reply: handle = %" PRIu64 ", offset = %" PRIu64 ", len = %zu" +nbd_co_send_extents(uint64_t handle, unsigned int extents, uint32_t id, uint64_t length, int last) "Send block status reply: handle = %" PRIu64 ", extents = %u, context = %d (extents cover %" PRIu64 " bytes, last chunk = %d)" nbd_co_send_structured_error(uint64_t handle, int err, const char *errname, const char *msg) "Send structured error reply: handle = %" PRIu64 ", error = %d (%s), msg = '%s'" nbd_co_receive_request_decode_type(uint64_t handle, uint16_t type, const char *name) "Decoding type: handle = %" PRIu64 ", type = %" PRIu16 " (%s)" nbd_co_receive_request_payload_received(uint64_t handle, uint32_t len) "Payload received: handle = %" PRIu64 ", len = %" PRIu32 |