diff options
Diffstat (limited to 'nbd/server.c')
| -rw-r--r-- | nbd/server.c | 385 |
1 files changed, 332 insertions, 53 deletions
diff --git a/nbd/server.c b/nbd/server.c index 9e1f227178..274604609f 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); @@ -88,10 +98,11 @@ static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); * as selected by NBD_OPT_SET_META_CONTEXT. Also used for * NBD_OPT_LIST_META_CONTEXT. */ typedef struct NBDExportMetaContexts { - char export_name[NBD_MAX_NAME_SIZE + 1]; + NBDExport *exp; 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 { @@ -399,10 +410,9 @@ static int nbd_negotiate_handle_list(NBDClient *client, Error **errp) return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); } -static void nbd_check_meta_export_name(NBDClient *client) +static void nbd_check_meta_export(NBDClient *client) { - client->export_meta.valid &= !strcmp(client->exp->name, - client->export_meta.export_name); + client->export_meta.valid &= client->exp == client->export_meta.exp; } /* Send a reply to NBD_OPT_EXPORT_NAME. @@ -456,7 +466,7 @@ static int nbd_negotiate_handle_export_name(NBDClient *client, QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); nbd_export_get(client->exp); - nbd_check_meta_export_name(client); + nbd_check_meta_export(client); return 0; } @@ -650,7 +660,7 @@ static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags, client->exp = exp; QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); nbd_export_get(client->exp); - nbd_check_meta_export_name(client); + nbd_check_meta_export(client); rc = 1; } return rc; @@ -734,45 +744,135 @@ static int nbd_negotiate_send_meta_context(NBDClient *client, return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0; } +/* Read strlen(@pattern) bytes, and set @match to true if they match @pattern. + * @match is never set to false. + * + * Return -errno on I/O error, 0 if option was completely handled by + * sending a reply about inconsistent lengths, or 1 on success. + * + * Note: return code = 1 doesn't mean that we've read exactly @pattern. + * It only means that there are no errors. + */ +static int nbd_meta_pattern(NBDClient *client, const char *pattern, bool *match, + Error **errp) +{ + int ret; + char *query; + size_t len = strlen(pattern); + + assert(len); + + query = g_malloc(len); + ret = nbd_opt_read(client, query, len, errp); + if (ret <= 0) { + g_free(query); + return ret; + } + + if (strncmp(query, pattern, len) == 0) { + trace_nbd_negotiate_meta_query_parse(pattern); + *match = true; + } else { + trace_nbd_negotiate_meta_query_skip("pattern not matched"); + } + g_free(query); + + return 1; +} + +/* + * Read @len bytes, and set @match to true if they match @pattern, or if @len + * is 0 and the client is performing _LIST_. @match is never set to false. + * + * Return -errno on I/O error, 0 if option was completely handled by + * sending a reply about inconsistent lengths, or 1 on success. + * + * Note: return code = 1 doesn't mean that we've read exactly @pattern. + * It only means that there are no errors. + */ +static int nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern, + uint32_t len, bool *match, Error **errp) +{ + if (len == 0) { + if (client->opt == NBD_OPT_LIST_META_CONTEXT) { + *match = true; + } + trace_nbd_negotiate_meta_query_parse("empty"); + return 1; + } + + if (len != strlen(pattern)) { + trace_nbd_negotiate_meta_query_skip("different lengths"); + return nbd_opt_skip(client, len, errp); + } + + return nbd_meta_pattern(client, pattern, match, errp); +} + /* nbd_meta_base_query * - * Handle query to 'base' namespace. For now, only base:allocation context is - * available in it. 'len' is the amount of text remaining to be read from + * Handle queries to 'base' namespace. For now, only the base:allocation + * context is available. 'len' is the amount of text remaining to be read from * the current name, after the 'base:' 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. */ + * sending a reply about inconsistent lengths, or 1 on success. + */ static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta, uint32_t len, Error **errp) { + return nbd_meta_empty_or_pattern(client, "allocation", len, + &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; - char query[sizeof("allocation") - 1]; - size_t alen = strlen("allocation"); + + 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->base_allocation = true; + meta->bitmap = true; } - trace_nbd_negotiate_meta_query_parse("base:"); + trace_nbd_negotiate_meta_query_parse("empty"); return 1; } - if (len != alen) { - trace_nbd_negotiate_meta_query_skip("not base:allocation"); + if (len < dirty_bitmap_len) { + trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:"); return nbd_opt_skip(client, len, errp); } - ret = nbd_opt_read(client, query, len, errp); + len -= dirty_bitmap_len; + ret = nbd_meta_pattern(client, "dirty-bitmap:", &dirty_bitmap, errp); if (ret <= 0) { return ret; } - - if (strncmp(query, "allocation", alen) == 0) { - meta->base_allocation = true; + 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("base:allocation"); - return 1; + 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 @@ -790,9 +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); @@ -801,24 +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); } - 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 @@ -829,7 +937,7 @@ static int nbd_negotiate_meta_queries(NBDClient *client, NBDExportMetaContexts *meta, Error **errp) { int ret; - NBDExport *exp; + char export_name[NBD_MAX_NAME_SIZE + 1]; NBDExportMetaContexts local_meta; uint32_t nb_queries; int i; @@ -848,15 +956,15 @@ static int nbd_negotiate_meta_queries(NBDClient *client, memset(meta, 0, sizeof(*meta)); - ret = nbd_opt_read_name(client, meta->export_name, NULL, errp); + ret = nbd_opt_read_name(client, export_name, NULL, errp); if (ret <= 0) { return ret; } - exp = nbd_export_find(meta->export_name); - if (exp == NULL) { + meta->exp = nbd_export_find(export_name); + if (meta->exp == NULL) { return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp, - "export '%s' not present", meta->export_name); + "export '%s' not present", export_name); } ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), errp); @@ -865,7 +973,7 @@ static int nbd_negotiate_meta_queries(NBDClient *client, } cpu_to_be32s(&nb_queries); trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt), - meta->export_name, nb_queries); + export_name, nb_queries); if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) { /* enable all known contexts */ @@ -888,6 +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; @@ -1134,7 +1252,7 @@ static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) int ret; const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA | - NBD_FLAG_SEND_WRITE_ZEROES); + NBD_FLAG_SEND_WRITE_ZEROES | NBD_FLAG_SEND_CACHE); bool oldStyle; /* Old style negotiation header, no room for options @@ -1516,6 +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); } } @@ -1757,9 +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; @@ -1769,7 +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); @@ -1779,8 +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; @@ -1791,7 +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 @@ -1826,7 +2034,9 @@ static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, return -EIO; } - if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE) { + if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE || + request->type == NBD_CMD_CACHE) + { if (request->len > NBD_MAX_BUFFER_SIZE) { error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", request->len, NBD_MAX_BUFFER_SIZE); @@ -1911,7 +2121,7 @@ static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, int ret; NBDExport *exp = client->exp; - assert(request->type == NBD_CMD_READ); + assert(request->type == NBD_CMD_READ || request->type == NBD_CMD_CACHE); /* XXX: NBD Protocol only documents use of FUA with WRITE */ if (request->flags & NBD_CMD_FLAG_FUA) { @@ -1930,7 +2140,7 @@ static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, ret = blk_pread(exp->blk, request->from + exp->dev_offset, data, request->len); - if (ret < 0) { + if (ret < 0 || request->type == NBD_CMD_CACHE) { return nbd_send_generic_reply(client, request->handle, ret, "reading from file failed", errp); } @@ -1963,6 +2173,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client, switch (request->type) { case NBD_CMD_READ: + case NBD_CMD_CACHE: return nbd_do_cmd_read(client, request, data, errp); case NBD_CMD_WRITE: @@ -2007,11 +2218,38 @@ static coroutine_fn int nbd_handle_request(NBDClient *client, "discard failed", errp); case NBD_CMD_BLOCK_STATUS: - 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 (!request->len) { + return nbd_send_generic_reply(client, request->handle, -EINVAL, + "need non-zero length", 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", @@ -2163,3 +2401,44 @@ 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); +} |