Mostly finish primary-OSD-read

osd.h

@@ -30,13 +30,63 @@
 #define CL_WRITE_REPLY 2
 #define CL_WRITE_DATA 3
 #define MAX_EPOLL_EVENTS 16
+#define OSD_OP_INLINE_BUF_COUNT 4
 
 #define PEER_CONNECTING 1
 #define PEER_CONNECTED 2
 
 //#define OSD_STUB
 
-// FIXME: add types for pg_num and osd_num?
+struct osd_op_buf_t
+{
+    void *buf;
+    int len;
+};
+
+struct osd_op_buf_list_t
+{
+    int count = 0, alloc = 0, sent = 0;
+    osd_op_buf_t *buf = NULL;
+    osd_op_buf_t inline_buf[OSD_OP_INLINE_BUF_COUNT];
+
+    ~osd_op_buf_list_t()
+    {
+        if (buf && buf != inline_buf)
+        {
+            free(buf);
+        }
+    }
+
+    inline void push_back(void *nbuf, int len)
+    {
+        if (count >= alloc)
+        {
+            if (!alloc)
+            {
+                alloc = OSD_OP_INLINE_BUF_COUNT;
+                buf = inline_buf;
+            }
+            else if (buf == inline_buf)
+            {
+                int old = alloc;
+                alloc = ((alloc/16)*16 + 1);
+                buf = (osd_op_buf_t*)malloc(sizeof(osd_op_buf_t) * alloc);
+                memcpy(buf, inline_buf, sizeof(osd_op_buf_t)*old);
+            }
+            else
+            {
+                alloc = ((alloc/16)*16 + 1);
+                buf = (osd_op_buf_t*)realloc(buf, sizeof(osd_op_buf_t) * alloc);
+            }
+        }
+        buf[count++] = { .buf = nbuf, .len = len };
+    }
+
+    inline osd_op_buf_t & operator [] (int i)
+    {
+        return buf[i];
+    }
+};
 
 struct osd_op_t
 {
@@ -54,14 +104,17 @@ struct osd_op_t
     };
     blockstore_op_t bs_op;
     void *buf = NULL;
+    void *op_data = NULL;
     std::function<void(osd_op_t*)> callback;
 
+    osd_op_buf_list_t send_list;
+
     ~osd_op_t();
 };
 
 struct osd_peer_def_t
 {
-    uint64_t osd_num = 0;
+    osd_num_t osd_num = 0;
     std::string addr;
     int port = 0;
     time_t last_connect_attempt = 0;
@@ -74,8 +127,7 @@ struct osd_client_t
     int peer_fd;
     int peer_state;
     std::function<void(int)> connect_callback;
-    // osd numbers begin with 1
-    uint64_t osd_num = 0;
+    osd_num_t osd_num = 0;
 
     // Read state
     bool read_ready = false;
@@ -103,11 +155,14 @@ struct osd_client_t
     int write_state = 0;
 };
 
+struct osd_primary_read_t;
+struct osd_read_stripe_t;
+
 class osd_t
 {
     // config
 
-    uint64_t osd_num = 1; // OSD numbers start with 1
+    osd_num_t osd_num = 1; // OSD numbers start with 1
     bool run_primary = false;
     std::vector<osd_peer_def_t> peers;
     blockstore_config_t config;
@@ -156,7 +211,7 @@ class osd_t
     void outbox_push(osd_client_t & cl, osd_op_t *op);
 
     // peer handling (primary OSD logic)
-    void connect_peer(unsigned osd_num, const char *peer_host, int peer_port, std::function<void(int)> callback);
+    void connect_peer(osd_num_t osd_num, const char *peer_host, int peer_port, std::function<void(int)> callback);
     void handle_connect_result(int peer_fd);
     void stop_client(int peer_fd);
     osd_peer_def_t parse_peer(std::string peer);
@@ -178,6 +233,10 @@ class osd_t
     void exec_primary_write(osd_op_t *cur_op);
     void exec_primary_sync(osd_op_t *cur_op);
     void make_primary_reply(osd_op_t *op);
+    void finish_primary_op(osd_op_t *cur_op, int retval);
+    void handle_primary_read_subop(osd_op_t *cur_op, int ok);
+    int extend_missing_stripes(osd_read_stripe_t *stripes, osd_num_t *target_set, int minsize, int size);
+    void submit_read_subops(int read_pg_size, const uint64_t* target_set, osd_op_t *cur_op);
 public:
     osd_t(blockstore_config_t & config, blockstore_t *bs, ring_loop_t *ringloop);
     ~osd_t();

osd_exec_secondary.cpp

@@ -139,6 +139,7 @@ void osd_t::make_reply(osd_op_t *op)
     {
         std::string *str = (std::string*)op->buf;
         op->reply.hdr.retval = str->size()+1;
+        op->send_list.push_back((void*)str->c_str(), op->reply.hdr.retval);
     }
     else
     {
@@ -150,4 +151,14 @@ void osd_t::make_reply(osd_op_t *op)
         else if (op->op.hdr.opcode == OSD_OP_SECONDARY_DELETE)
             op->reply.sec_del.version = op->bs_op.version;
     }
+    if (op->op.hdr.opcode == OSD_OP_SECONDARY_READ &&
+        op->reply.hdr.retval > 0)
+    {
+        op->send_list.push_back(op->buf, op->reply.hdr.retval);
+    }
+    else if (op->op.hdr.opcode == OSD_OP_SECONDARY_LIST &&
+        op->reply.hdr.retval > 0)
+    {
+        op->send_list.push_back(op->buf, op->reply.hdr.retval * sizeof(obj_ver_id));
+    }
 }

osd_ops.h

@@ -26,6 +26,9 @@
 #define OSD_RW_ALIGN                512
 #define OSD_RW_MAX                  64*1024*1024
 
+typedef uint64_t osd_num_t;
+typedef uint32_t pg_num_t;
+
 // common request and reply headers
 struct __attribute__((__packed__)) osd_op_header_t
 {
@@ -128,7 +131,7 @@ struct __attribute__((__packed__)) osd_op_secondary_list_t
 {
     osd_op_header_t header;
     // placement group total number and total count
-    uint32_t pgnum, pgtotal;
+    pg_num_t pgnum, pgtotal;
 };
 
 struct __attribute__((__packed__)) osd_reply_secondary_list_t

osd_peering.cpp

@@ -43,7 +43,7 @@ osd_peer_def_t osd_t::parse_peer(std::string peer)
     return r;
 }
 
-void osd_t::connect_peer(unsigned osd_num, const char *peer_host, int peer_port, std::function<void(int)> callback)
+void osd_t::connect_peer(osd_num_t osd_num, const char *peer_host, int peer_port, std::function<void(int)> callback)
 {
     struct sockaddr_in addr;
     int r;
@@ -184,7 +184,7 @@ void osd_t::start_pg_peering(int pg_idx)
     auto & pg = pgs[pg_idx];
     auto ps = pg.peering_state = new pg_peering_state_t();
     {
-        uint64_t osd_num = this->osd_num;
+        osd_num_t osd_num = this->osd_num;
         osd_op_t *op = new osd_op_t();
         op->op_type = 0;
         op->peer_fd = 0;
@@ -211,7 +211,7 @@ void osd_t::start_pg_peering(int pg_idx)
     }
     for (int i = 0; i < peers.size(); i++)
     {
-        uint64_t osd_num = peers[i].osd_num;
+        osd_num_t osd_num = peers[i].osd_num;
         auto & cl = clients[osd_peer_fds[peers[i].osd_num]];
         osd_op_t *op = new osd_op_t();
         op->op_type = OSD_OP_OUT;

osd_peering_pg.h

@@ -3,6 +3,7 @@
 #include <algorithm>
 
 #include "object_id.h"
+#include "osd_ops.h"
 
 #include "sparsepp/sparsepp/spp.h"
 
@@ -31,7 +32,7 @@
 struct pg_obj_loc_t
 {
     uint64_t role;
-    uint64_t osd_num;
+    osd_num_t osd_num;
     bool stable;
 };
 
@@ -39,7 +40,7 @@ typedef std::vector<pg_obj_loc_t> pg_osd_set_t;
 
 struct pg_osd_set_state_t
 {
-    std::vector<uint64_t> read_target;
+    std::vector<osd_num_t> read_target;
     pg_osd_set_t osd_set;
     uint64_t state = 0;
     uint64_t object_count = 0;
@@ -55,7 +56,7 @@ struct pg_list_result_t
 struct pg_peering_state_t
 {
     // osd_num -> list result
-    spp::sparse_hash_map<uint64_t, pg_list_result_t> list_results;
+    spp::sparse_hash_map<osd_num_t, pg_list_result_t> list_results;
     int list_done = 0;
 };
 
@@ -100,10 +101,10 @@ struct pg_t
 {
     int state;
     uint64_t pg_cursize = 3, pg_size = 3, pg_minsize = 2;
-    uint64_t pg_num;
+    pg_num_t pg_num;
     uint64_t clean_count = 0;
     // target_set = (role => osd_num or UINT64_MAX if missing). role numbers start with zero
-    std::vector<uint64_t> target_set;
+    std::vector<osd_num_t> target_set;
     // moved object map. by default, each object is considered to reside on the target_set.
     // this map stores all objects that differ.
     // it may consume up to ~ (raw storage / object size) * 24 bytes in the worst case scenario

osd_primary.cpp

@@ -1,192 +1,272 @@
 #include "osd.h"
 #include "xor.h"
 
+// read: read directly or read paired stripe(s), reconstruct, return
+// write: read paired stripe(s), modify, write
+// nuance: take care to read the same version from paired stripes!
+// if there are no write requests in progress we're good (stripes must be in sync)
+// and... remember the last readable version during a write request
+// and... postpone other write requests to the same stripe until the completion of previous ones
+//
+// sync: sync peers, get unstable versions from somewhere, stabilize them
+
+struct off_len_t
+{
+    uint64_t offset, len;
+};
+
+struct osd_read_stripe_t
+{
+    uint64_t pos;
+    uint32_t start, end;
+    uint32_t real_start, real_end;
+};
+
+struct osd_primary_read_t
+{
+    pg_num_t pg_num;
+    object_id oid;
+    uint64_t target_ver;
+    int n_subops = 0, done = 0, errors = 0;
+    int degraded = 0, pg_size, pg_minsize;
+    osd_read_stripe_t *stripes;
+    osd_op_t *subops = NULL;
+};
+
+void osd_t::finish_primary_op(osd_op_t *cur_op, int retval)
+{
+    // FIXME add separate magics
+    cur_op->reply.hdr.magic = SECONDARY_OSD_REPLY_MAGIC;
+    cur_op->reply.hdr.id = cur_op->op.hdr.id;
+    cur_op->reply.hdr.opcode = cur_op->op.hdr.opcode;
+    cur_op->reply.hdr.retval = retval;
+    outbox_push(this->clients[cur_op->peer_fd], cur_op);
+}
+
 void osd_t::exec_primary_read(osd_op_t *cur_op)
 {
-    // read: read directly or read paired stripe(s), reconstruct, return
-    // write: read paired stripe(s), modify, write
-    // nuance: take care to read the same version from paired stripes!
-    // if there are no write requests in progress we're good (stripes must be in sync)
-    // and... remember the last readable version during a write request
-    // and... postpone other write requests to the same stripe until the completion of previous ones
-    //
-    // sync: sync peers, get unstable versions from somewhere, stabilize them
     object_id oid = {
         .inode = cur_op->op.rw.inode,
         .stripe = (cur_op->op.rw.offset / (bs_block_size*2)) << STRIPE_SHIFT,
     };
-    uint64_t start = cur_op->op.rw.offset, end = cur_op->op.rw.offset + cur_op->op.rw.len;
-    unsigned pg_num = (oid % pg_count); // FIXME +1
+    uint64_t start = cur_op->op.rw.offset;
+    uint64_t end = cur_op->op.rw.offset + cur_op->op.rw.len;
+    pg_num_t pg_num = (oid % pg_count); // FIXME +1
     if (((end - 1) / (bs_block_size*2)) != oid.stripe ||
         (start % bs_disk_alignment) || (end % bs_disk_alignment) ||
         pg_num > pgs.size())
     {
-        // FIXME add separate magics
-        cur_op->reply.hdr.magic = SECONDARY_OSD_REPLY_MAGIC;
-        cur_op->reply.hdr.id = cur_op->op.hdr.id;
-        cur_op->reply.hdr.opcode = cur_op->op.hdr.opcode;
-        cur_op->reply.hdr.retval = -EINVAL;
-        outbox_push(clients[cur_op->peer_fd], cur_op);
+        finish_primary_op(cur_op, -EINVAL);
         return;
     }
-    // role -> start, end
-    uint64_t reads[pgs[pg_num].pg_minsize*2] = { 0 };
+    osd_primary_read_t *op_data = (osd_primary_read_t*)calloc(
+        sizeof(osd_primary_read_t) + sizeof(osd_read_stripe_t) * pgs[pg_num].pg_size, 1
+    );
+    osd_read_stripe_t *stripes = (op_data->stripes = ((osd_read_stripe_t*)(op_data+1)));
+    cur_op->op_data = op_data;
     for (int role = 0; role < pgs[pg_num].pg_minsize; role++)
     {
         if (start < (1+role)*bs_block_size && end > role*bs_block_size)
         {
-            reads[role*2] = start < role*bs_block_size ? 0 : start-role*bs_block_size;
-            reads[role*2+1] = end > (role+1)*bs_block_size ? bs_block_size : end-role*bs_block_size;
+            stripes[role].real_start = stripes[role].start
+                = start < role*bs_block_size ? 0 : start-role*bs_block_size;
+            stripes[role].end = stripes[role].real_end
+                = end > (role+1)*bs_block_size ? bs_block_size : end-role*bs_block_size;
         }
     }
-    auto vo_it = pgs[pg_num].ver_override.find(oid);
-    uint64_t target_ver = vo_it != pgs[pg_num].ver_override.end() ? vo_it->second : UINT64_MAX;
+    {
+        auto vo_it = pgs[pg_num].ver_override.find(oid);
+        op_data->target_ver = vo_it != pgs[pg_num].ver_override.end() ? vo_it->second : UINT64_MAX;
+    }
     if (pgs[pg_num].pg_cursize == 3)
     {
         // Fast happy-path
-        void *buf = memalign(MEM_ALIGNMENT, cur_op->op.rw.len);
-        
+        submit_read_subops(pgs[pg_num].pg_minsize, pgs[pg_num].target_set.data(), cur_op);
+        cur_op->send_list.push_back(cur_op->buf, cur_op->op.rw.len);
     }
     else
     {
         // PG is degraded
-        auto it = pgs[pg_num].obj_states.find(oid);
-        std::vector<uint64_t> & target_set = (it != pgs[pg_num].obj_states.end()
-            ? it->second->read_target
-            : pgs[pg_num].target_set);
-        uint64_t real_reads[pgs[pg_num].pg_size*2] = { 0 };
-        memcpy(real_reads, reads, sizeof(uint64_t)*pgs[pg_num].pg_minsize*2);
-        for (int role = 0; role < pgs[pg_num].pg_minsize; role++)
+        uint64_t* target_set;
+        {
+            auto it = pgs[pg_num].obj_states.find(oid);
+            target_set = (it != pgs[pg_num].obj_states.end()
+                ? it->second->read_target.data()
+                : pgs[pg_num].target_set.data());
+        }
+        if (extend_missing_stripes(stripes, target_set, pgs[pg_num].pg_minsize, pgs[pg_num].pg_size) < 0)
+        {
+            free(op_data);
+            finish_primary_op(cur_op, -EIO);
+            return;
+        }
+        // Submit reads
+        submit_read_subops(pgs[pg_num].pg_size, target_set, cur_op);
+        op_data->pg_minsize = pgs[pg_num].pg_minsize;
+        op_data->pg_size = pgs[pg_num].pg_size;
+        op_data->degraded = 1;
+    }
+}
+
+void osd_t::handle_primary_read_subop(osd_op_t *cur_op, int ok)
+{
+    osd_primary_read_t *op_data = (osd_primary_read_t*)cur_op->op_data;
+    if (!ok)
+        op_data->errors++;
+    else
+        op_data->done++;
+    if ((op_data->errors + op_data->done) >= op_data->n_subops)
+    {
+        delete[] op_data->subops;
+        op_data->subops = NULL;
+        if (op_data->errors > 0)
         {
-            if (reads[role*2+1] != 0 && target_set[role] == 0)
+            free(op_data);
+            cur_op->op_data = NULL;
+            finish_primary_op(cur_op, -EIO);
+            return;
+        }
+        if (op_data->degraded)
+        {
+            // Reconstruct missing stripes
+            osd_read_stripe_t *stripes = op_data->stripes;
+            for (int role = 0; role < op_data->pg_minsize; role++)
             {
-                // Stripe is missing. Extend read to other stripes.
-                // We need at least pg_minsize stripes to recover the lost part.
-                int exist = 0;
-                for (int j = 0; j < pgs[pg_num].pg_size; j++)
+                if (stripes[role].end != 0 && stripes[role].real_end == 0)
                 {
-                    if (target_set[j] != 0)
-                    {
-                        if (real_reads[j*2+1] == 0 || j >= pgs[pg_num].pg_minsize)
-                        {
-                            real_reads[j*2] = reads[role*2];
-                            real_reads[j*2+1] = reads[role*2+1];
-                        }
-                        else
-                        {
-                            real_reads[j*2] = reads[j*2] < reads[role*2] ? reads[j*2] : reads[role*2];
-                            real_reads[j*2+1] = reads[j*2+1] > reads[role*2+1] ? reads[j*2+1] : reads[role*2+1];
-                        }
-                        exist++;
-                        if (exist >= pgs[pg_num].pg_minsize)
-                        {
-                            break;
-                        }
-                    }
+                    int other = role == 0 ? 1 : 0;
+                    int parity = op_data->pg_size-1;
+                    memxor(
+                        cur_op->buf + stripes[other].pos + (stripes[other].real_start - stripes[role].start),
+                        cur_op->buf + stripes[parity].pos + (stripes[parity].real_start - stripes[role].start),
+                        cur_op->buf + stripes[role].pos, stripes[role].end - stripes[role].start
+                    );
                 }
-                if (exist < pgs[pg_num].pg_minsize)
+                if (stripes[role].end != 0)
                 {
-                    // Object is unreadable
-                    cur_op->reply.hdr.magic = SECONDARY_OSD_REPLY_MAGIC;
-                    cur_op->reply.hdr.id = cur_op->op.hdr.id;
-                    cur_op->reply.hdr.opcode = cur_op->op.hdr.opcode;
-                    cur_op->reply.hdr.retval = -EIO;
-                    outbox_push(clients[cur_op->peer_fd], cur_op);
-                    return;
+                    // Send buffer in parts to avoid copying
+                    cur_op->send_list.push_back(
+                        cur_op->buf + stripes[role].pos + (stripes[role].real_start - stripes[role].start), stripes[role].end
+                    );
                 }
             }
         }
-        uint64_t pos[pgs[pg_num].pg_size];
-        uint64_t buf_size = 0;
-        int n_subops = 0;
-        for (int role = 0; role < pgs[pg_num].pg_size; role++)
-        {
-            if (real_reads[role*2+1] != 0)
-            {
-                n_subops++;
-                pos[role] = buf_size;
-                buf_size += real_reads[role*2+1];
-            }
-        }
-        void *buf = memalign(MEM_ALIGNMENT, buf_size);
-        // Submit reads
-        osd_op_t read_ops[n_subops];
-        int subop = 0;
-        int errors = 0, done = 0;
-        for (int role = 0; role < pgs[pg_num].pg_size; role++)
+        free(op_data);
+        cur_op->op_data = NULL;
+        finish_primary_op(cur_op, cur_op->op.rw.len);
+    }
+}
+
+int osd_t::extend_missing_stripes(osd_read_stripe_t *stripes, osd_num_t *target_set, int minsize, int size)
+{
+    for (int role = 0; role < minsize; role++)
+    {
+        if (stripes[role*2+1].end != 0 && target_set[role] == 0)
         {
-            uint64_t role_osd_num = target_set[role];
-            if (role_osd_num != 0)
+            // Stripe is missing. Extend read to other stripes.
+            // We need at least pg_minsize stripes to recover the lost part.
+            int exist = 0;
+            for (int j = 0; j < size; j++)
             {
-                if (role_osd_num == this->osd_num)
+                if (target_set[j] != 0)
                 {
-                    read_ops[subop].bs_op = {
-                        .opcode = BS_OP_READ,
-                        .callback = [&](blockstore_op_t *op)
-                        {
-                            if (op->retval < op->len)
-                                errors++;
-                            else
-                                done++;
-                            // continue op
-                        },
-                        .oid = {
-                            .inode = oid.inode,
-                            .stripe = oid.stripe | role,
-                        },
-                        .version = target_ver,
-                        .offset = real_reads[role*2],
-                        .len = real_reads[role*2+1] - real_reads[role*2],
-                        .buf = buf + pos[role],
-                    };
-                    bs->enqueue_op(&read_ops[subop].bs_op);
-                }
-                else
-                {
-                    read_ops[subop].op_type = OSD_OP_OUT;
-                    read_ops[subop].peer_fd = osd_peer_fds.at(role_osd_num);
-                    read_ops[subop].op.sec_rw = {
-                        .header = {
-                            .magic = SECONDARY_OSD_OP_MAGIC,
-                            .id = next_subop_id++,
-                            .opcode = OSD_OP_SECONDARY_READ,
-                        },
-                        .oid = {
-                            .inode = oid.inode,
-                            .stripe = oid.stripe | role,
-                        },
-                        .version = target_ver,
-                        .offset = real_reads[role*2],
-                        .len = real_reads[role*2+1] - real_reads[role*2],
-                    };
-                    read_ops[subop].buf = buf + pos[role];
-                    read_ops[subop].callback = [&](osd_op_t *osd_subop)
+                    if (stripes[j].real_end == 0 || j >= minsize)
+                    {
+                        stripes[j].real_start = stripes[role].start;
+                        stripes[j].real_end = stripes[role].end;
+                    }
+                    else
                     {
-                        if (osd_subop->reply.hdr.retval < osd_subop->op.sec_rw.len)
-                            errors++;
-                        else
-                            done++;
-                        // continue op
-                    };
+                        stripes[j].real_start = stripes[j].start < stripes[role].start ? stripes[j].start : stripes[role].start;
+                        stripes[j].real_end = stripes[j].end > stripes[role].end ? stripes[j].end : stripes[role].end;
+                    }
+                    exist++;
+                    if (exist >= minsize)
+                    {
+                        break;
+                    }
                 }
-                subop++;
             }
+            if (exist < minsize)
+            {
+                // Less than minsize stripes are available for this object
+                return -1;
+            }
+        }
+    }
+    return 0;
+}
+
+void osd_t::submit_read_subops(int read_pg_size, const uint64_t* target_set, osd_op_t *cur_op)
+{
+    osd_primary_read_t *op_data = (osd_primary_read_t*)cur_op->op_data;
+    osd_read_stripe_t *stripes = op_data->stripes;
+    uint64_t buf_size = 0;
+    int n_subops = 0;
+    for (int role = 0; role < read_pg_size; role++)
+    {
+        if (stripes[role].real_end != 0)
+        {
+            n_subops++;
+            stripes[role].pos = buf_size;
+            buf_size += stripes[role].real_end - stripes[role].real_start;
         }
-        // Reconstruct missing stripes
-        for (int role = 0; role < pgs[pg_num].pg_minsize; role++)
+    }
+    osd_op_t *subops = new osd_op_t[n_subops];
+    cur_op->buf = memalign(MEM_ALIGNMENT, buf_size);
+    op_data->n_subops = n_subops;
+    op_data->subops = subops;
+    int subop = 0;
+    for (int role = 0; role < read_pg_size; role++)
+    {
+        auto role_osd_num = target_set[role];
+        if (role_osd_num != 0)
         {
-            if (reads[role*2+1] != 0 && target_set[role] == 0)
+            if (role_osd_num == this->osd_num)
             {
-                int other = role == 0 ? 1 : 0;
-                int parity = pgs[pg_num].pg_size-1;
-                memxor(
-                    buf + pos[other] + (real_reads[other*2]-reads[role*2]),
-                    buf + pos[parity] + (real_reads[parity*2]-reads[role*2]),
-                    buf + pos[role], reads[role*2+1]-reads[role*2]
-                );
+                subops[subop].bs_op = {
+                    .opcode = BS_OP_READ,
+                    .callback = [this, cur_op](blockstore_op_t *subop)
+                    {
+                        handle_primary_read_subop(cur_op, subop->retval == subop->len);
+                    },
+                    .oid = {
+                        .inode = op_data->oid.inode,
+                        .stripe = op_data->oid.stripe | role,
+                    },
+                    .version = op_data->target_ver,
+                    .offset = stripes[role].real_start,
+                    .len = stripes[role].real_end - stripes[role].real_start,
+                    .buf = cur_op->buf + stripes[role].pos,
+                };
+                bs->enqueue_op(&subops[subop].bs_op);
+            }
+            else
+            {
+                subops[subop].op_type = OSD_OP_OUT;
+                subops[subop].peer_fd = this->osd_peer_fds.at(role_osd_num);
+                subops[subop].op.sec_rw = {
+                    .header = {
+                        .magic = SECONDARY_OSD_OP_MAGIC,
+                        .id = this->next_subop_id++,
+                        .opcode = OSD_OP_SECONDARY_READ,
+                    },
+                    .oid = {
+                        .inode = op_data->oid.inode,
+                        .stripe = op_data->oid.stripe | role,
+                    },
+                    .version = op_data->target_ver,
+                    .offset = stripes[role].real_start,
+                    .len = stripes[role].real_end - stripes[role].real_start,
+                };
+                subops[subop].buf = cur_op->buf + stripes[role].pos;
+                subops[subop].callback = [this, cur_op](osd_op_t *subop)
+                {
+                    handle_primary_read_subop(cur_op, subop->reply.hdr.retval == subop->op.sec_rw.len);
+                };
             }
+            subop++;
         }
-        // Send buffer in parts to avoid copying
     }
 }
 

osd_send.cpp

@@ -46,7 +46,7 @@ void osd_t::send_replies()
         cl.write_iov.iov_len = cl.write_remaining;
         cl.write_msg.msg_iov = &cl.write_iov;
         cl.write_msg.msg_iovlen = 1;
-        // FIXME: This is basically a busy-loop. It's probably better to add epoll here
+        // FIXME: This is basically a busy-loop. It may be better to add epoll here(?)
         data->callback = [this, peer_fd](ring_data_t *data) { handle_send(data, peer_fd); };
         my_uring_prep_sendmsg(sqe, peer_fd, &cl.write_msg, 0);
         cl.write_state = cl.write_state | SQE_SENT;
@@ -76,67 +76,16 @@ void osd_t::handle_send(ring_data_t *data, int peer_fd)
             {
                 cl.write_buf = NULL;
                 osd_op_t *cur_op = cl.write_op;
-                if (cl.write_state == CL_WRITE_REPLY)
+                if (cur_op->send_list.sent < cur_op->send_list.count)
                 {
                     // Send data
-                    if (cur_op->op_type == OSD_OP_IN)
-                    {
-                        if (cur_op->op.hdr.opcode == OSD_OP_SECONDARY_READ &&
-                            cur_op->reply.hdr.retval > 0)
-                        {
-                            cl.write_buf = cur_op->buf;
-                            cl.write_remaining = cur_op->reply.hdr.retval;
-                            cl.write_state = CL_WRITE_DATA;
-                        }
-                        else if (cur_op->op.hdr.opcode == OSD_OP_SECONDARY_LIST &&
-                            cur_op->reply.hdr.retval > 0)
-                        {
-                            cl.write_buf = cur_op->buf;
-                            cl.write_remaining = cur_op->reply.hdr.retval * sizeof(obj_ver_id);
-                            cl.write_state = CL_WRITE_DATA;
-                        }
-                        else if (cur_op->op.hdr.opcode == OSD_OP_SHOW_CONFIG &&
-                            cur_op->reply.hdr.retval > 0)
-                        {
-                            cl.write_buf = (void*)((std::string*)cur_op->buf)->c_str();
-                            cl.write_remaining = cur_op->reply.hdr.retval;
-                            cl.write_state = CL_WRITE_DATA;
-                        }
-                        else
-                        {
-                            goto op_done;
-                        }
-                    }
-                    else
-                    {
-                        if (cur_op->op.hdr.opcode == OSD_OP_SECONDARY_WRITE)
-                        {
-                            cl.write_buf = cur_op->buf;
-                            cl.write_remaining = cur_op->op.sec_rw.len;
-                            cl.write_state = CL_WRITE_DATA;
-                        }
-                        else if (cur_op->op.hdr.opcode == OSD_OP_SECONDARY_STABILIZE ||
-                            cur_op->op.hdr.opcode == OSD_OP_SECONDARY_ROLLBACK)
-                        {
-                            cl.write_buf = cur_op->buf;
-                            cl.write_remaining = cur_op->op.sec_stab.len;
-                            cl.write_state = CL_WRITE_DATA;
-                        }
-                        else if (cur_op->op.hdr.opcode == OSD_OP_WRITE)
-                        {
-                            cl.write_buf = cur_op->buf;
-                            cl.write_remaining = cur_op->op.rw.len;
-                            cl.write_state = CL_WRITE_DATA;
-                        }
-                        else
-                        {
-                            goto op_done;
-                        }
-                    }
+                    cl.write_buf = cur_op->send_list[cur_op->send_list.sent].buf;
+                    cl.write_remaining = cur_op->send_list[cur_op->send_list.sent].len;
+                    cur_op->send_list.sent++;
+                    cl.write_state = CL_WRITE_DATA;
                 }
-                else if (cl.write_state == CL_WRITE_DATA)
+                else
                 {
-                op_done:
                     // Done
                     if (cur_op->op_type == OSD_OP_IN)
                     {