Experimental: Handle degraded deletions by comparing object versions with epochs

mon/PGUtil.js

@@ -10,18 +10,25 @@ function add_pg_history(new_pg_history, new_pg, prev_pgs, prev_pg_history, old_p
     if (!new_pg_history[new_pg])
     {
         new_pg_history[new_pg] = {
-            osd_sets: {},
+            osd_set_epochs: {},
             all_peers: {},
             epoch: 0,
         };
     }
     const nh = new_pg_history[new_pg], oh = prev_pg_history[old_pg];
-    nh.osd_sets[prev_pgs[old_pg].join(' ')] = prev_pgs[old_pg];
+    nh.osd_set_epochs[prev_pgs[old_pg].join(' ')] = { osd_set: prev_pgs[old_pg] };
     if (oh && oh.osd_sets && oh.osd_sets.length)
     {
         for (const pg of oh.osd_sets)
         {
-            nh.osd_sets[pg.join(' ')] = pg;
+            nh.osd_set_epochs[pg.join(' ')] = { osd_set: pg };
+        }
+    }
+    if (oh && oh.osd_set_epochs && oh.osd_set_epochs.length)
+    {
+        for (const pg of oh.osd_set_epochs)
+        {
+            nh.osd_set_epochs[pg.osd_set.join(' ')] = { osd_set: pg.osd_set };
         }
     }
     if (oh && oh.all_peers && oh.all_peers.length)
@@ -39,7 +46,7 @@ function add_pg_history(new_pg_history, new_pg, prev_pgs, prev_pg_history, old_p
 
 function finish_pg_history(merged_history)
 {
-    merged_history.osd_sets = Object.values(merged_history.osd_sets);
+    merged_history.osd_set_epochs = Object.values(merged_history.osd_set_epochs);
     merged_history.all_peers = Object.values(merged_history.all_peers);
 }
 

mon/mon.js

@@ -276,7 +276,12 @@ const etcd_tree = {
         history: {
             /* <pool_id>: {
                 <pg_id>: {
-                    osd_sets: osd_num_t[][],
+                    osd_set_epochs: {
+                        osd_set: osd_num_t[],
+                        min_epoch: uint64_t,
+                        max_epoch: uint64_t,
+                    }[],
+                    osd_sets: osd_num_t[][], // outdated
                     all_peers: osd_num_t[],
                     epoch: uint64_t,
                 },
@@ -947,18 +952,6 @@ class Mon
                 osd_set,
                 primary: this.pick_primary(pool_id, osd_set, up_osds, aff_osds),
             };
-            if (prev_pgs[i] && prev_pgs[i].join(' ') != osd_set.join(' ') &&
-                prev_pgs[i].filter(osd_num => osd_num).length > 0)
-            {
-                pg_history[i] = pg_history[i] || {};
-                pg_history[i].osd_sets = pg_history[i].osd_sets || [];
-                pg_history[i].osd_sets.push(prev_pgs[i]);
-            }
-            if (pg_history[i] && pg_history[i].osd_sets)
-            {
-                pg_history[i].osd_sets = Object.values(pg_history[i].osd_sets
-                    .reduce((a, c) => { a[c.join(' ')] = c; return a; }, {}));
-            }
         });
         for (let i = 0; i < new_pgs.length || i < prev_pgs.length; i++)
         {

src/cluster_client_list.cpp

@@ -95,7 +95,7 @@ inode_list_t* cluster_client_t::list_inode_start(inode_t inode,
             }
             for (auto & hist_item: pg.target_history)
             {
-                for (auto pg_osd: hist_item)
+                for (auto pg_osd: hist_item.osd_set)
                 {
                     if (pg_osd != 0)
                     {
@@ -105,11 +105,14 @@ inode_list_t* cluster_client_t::list_inode_start(inode_t inode,
             }
             for (osd_num_t peer_osd: all_peers)
             {
-                r->list_osds.push_back((inode_list_osd_t){
-                    .pg = r,
-                    .osd_num = peer_osd,
-                    .sent = false,
-                });
+                if (st_cli.peer_states.find(peer_osd) != st_cli.peer_states.end())
+                {
+                    r->list_osds.push_back((inode_list_osd_t){
+                        .pg = r,
+                        .osd_num = peer_osd,
+                        .sent = false,
+                    });
+                }
             }
         }
         else

src/etcd_state_client.cpp

@@ -845,7 +845,27 @@ void etcd_state_client_t::parse_state(const etcd_kv_t & kv)
                 {
                     history_set.push_back(pg_osd.uint64_value());
                 }
-                pg_cfg.target_history.push_back(history_set);
+                pg_cfg.target_history.push_back((pg_history_set_t){ .osd_set = history_set });
+            }
+            // Newer format with epochs
+            for (auto hist_item: value["osd_set_epochs"].array_items())
+            {
+                pg_history_set_t history_set;
+                history_set.min_epoch = hist_item["min_epoch"].uint64_value();
+                history_set.max_epoch = hist_item["max_epoch"].uint64_value();
+                if (history_set.max_epoch < history_set.min_epoch)
+                {
+                    history_set.max_epoch = 0;
+                    history_set.min_epoch = 0;
+                }
+                for (auto pg_osd: hist_item["osd_set"].array_items())
+                {
+                    history_set.osd_set.push_back(pg_osd.uint64_value());
+                }
+                if (history_set.max_epoch || history_set.osd_set.size())
+                {
+                    pg_cfg.target_history.push_back(history_set);
+                }
             }
             // Include these additional OSDs when peering the PG
             for (auto pg_osd: value["all_peers"].array_items())

src/etcd_state_client.h

@@ -26,7 +26,7 @@ struct pg_config_t
     bool exists;
     osd_num_t primary;
     std::vector<osd_num_t> target_set;
-    std::vector<std::vector<osd_num_t>> target_history;
+    std::vector<pg_history_set_t> target_history;
     std::vector<osd_num_t> all_peers;
     bool pause;
     osd_num_t cur_primary;

src/osd_cluster.cpp

@@ -333,7 +333,10 @@ void osd_t::on_change_pg_history_hook(pool_id_t pool_id, pg_num_t pg_num)
             {
                 oid = op.first;
                 first = false;
-                continue_primary_write(op.second);
+                if (op.second->req.hdr.opcode == OSD_OP_DELETE)
+                    continue_primary_del(op.second);
+                else
+                    continue_primary_write(op.second);
             }
         }
     }
@@ -608,7 +611,7 @@ void osd_t::apply_pg_config()
                 }
                 for (auto & hist_item: pg_cfg.target_history)
                 {
-                    for (auto pg_osd: hist_item)
+                    for (auto pg_osd: hist_item.osd_set)
                     {
                         if (pg_osd != 0)
                         {
@@ -799,11 +802,40 @@ void osd_t::report_pg_states()
                 // Prevent race conditions (for the case when the monitor is updating this key at the same time)
                 pg.history_changed = false;
                 std::string history_key = base64_encode(st_cli.etcd_prefix+"/pg/history/"+std::to_string(pg.pool_id)+"/"+std::to_string(pg.pg_num));
+                json11::Json::array target_history;
+                for (auto & pgh: pg.target_history)
+                {
+                    target_history.push_back(json11::Json::object {
+                        { "osd_set", pgh.osd_set },
+                        { "min_epoch", pgh.min_epoch },
+                        { "max_epoch", pgh.max_epoch },
+                    });
+                }
+                std::vector<osd_num_t> all_peers;
+                for (auto peer_osd: pg.all_peers)
+                {
+                    bool found = false;
+                    for (auto target_peer: pg.target_set)
+                    {
+                        if (target_peer == peer_osd)
+                        {
+                            found = true;
+                            break;
+                        }
+                    }
+                    if (!found)
+                    {
+                        all_peers.push_back(peer_osd);
+                    }
+                }
                 json11::Json::object history_value = {
                     { "epoch", pg.epoch },
-                    { "all_peers", pg.all_peers },
-                    { "osd_sets", pg.target_history },
+                    { "osd_set_epochs", target_history },
                 };
+                if (all_peers.size())
+                {
+                    history_value["all_peers"] = all_peers;
+                }
                 checks.push_back(json11::Json::object {
                     { "target", "MOD" },
                     { "key", history_key },

src/osd_flush.cpp

@@ -268,6 +268,25 @@ bool osd_t::pick_next_recovery(osd_recovery_op_t &op)
 
 void osd_t::submit_recovery_op(osd_recovery_op_t *op)
 {
+    // Check if the object is deleted
+    bool is_deleted = false;
+    pool_id_t pool_id = INODE_POOL(op->oid.inode);
+    auto pool_cfg_it = st_cli.pool_config.find(pool_id);
+    if (pool_cfg_it != st_cli.pool_config.end())
+    {
+        pg_num_t pg_num = (op->oid.stripe/pool_cfg_it->second.pg_stripe_size) % pg_counts[pool_id] + 1; // like map_to_pg()
+        auto pg_it = pgs.find({ .pool_id = pool_id, .pg_num = pg_num });
+        if (pg_it != pgs.end())
+        {
+            pg_osd_set_state_t *object_state;
+            get_object_osd_set(pg_it->second, op->oid, pg_it->second.cur_set.data(), &object_state);
+            if (object_state && (object_state->state & OBJ_DELETED))
+            {
+                // Object is deleted, but not from all OSDs - delete remaining copies
+                is_deleted = true;
+            }
+        }
+    }
     op->osd_op = new osd_op_t();
     op->osd_op->op_type = OSD_OP_OUT;
     op->osd_op->req = (osd_any_op_t){
@@ -275,7 +294,7 @@ void osd_t::submit_recovery_op(osd_recovery_op_t *op)
             .header = {
                 .magic = SECONDARY_OSD_OP_MAGIC,
                 .id = 1,
-                .opcode = OSD_OP_WRITE,
+                .opcode = (uint64_t)(is_deleted ? OSD_OP_DELETE : OSD_OP_WRITE),
             },
             .inode = op->oid.inode,
             .offset = op->oid.stripe,

src/osd_id.h

@@ -3,6 +3,8 @@
 
 #pragma once
 
+#include <vector>
+
 #define POOL_SCHEME_REPLICATED 1
 #define POOL_SCHEME_XOR 2
 #define POOL_SCHEME_JERASURE 3
@@ -28,3 +30,9 @@ inline bool operator < (const pool_pg_num_t & a, const pool_pg_num_t & b)
 {
     return a.pool_id < b.pool_id || a.pool_id == b.pool_id && a.pg_num < b.pg_num;
 }
+
+struct pg_history_set_t
+{
+    std::vector<osd_num_t> osd_set;
+    uint64_t min_epoch, max_epoch;
+};

src/osd_peering.cpp

@@ -228,7 +228,7 @@ void osd_t::start_pg_peering(pg_t & pg)
         for (auto & history_set: pg.target_history)
         {
             bool found = true;
-            for (auto history_osd: history_set)
+            for (auto history_osd: history_set.osd_set)
             {
                 if (history_osd != 0)
                 {
@@ -539,47 +539,114 @@ void osd_t::finish_stop_pg(pg_t & pg)
     report_pg_state(pg);
 }
 
+static int count_nonzero_osds(const std::vector<osd_num_t> & v)
+{
+    int n = 0;
+    for (auto & osd_num: v)
+    {
+        if (osd_num != 0)
+        {
+            n++;
+        }
+    }
+    return n;
+}
+
 void osd_t::report_pg_state(pg_t & pg)
 {
     pg.print_state();
     this->pg_state_dirty.insert({ .pool_id = pg.pool_id, .pg_num = pg.pg_num });
-    if (pg.state == PG_ACTIVE && (pg.target_history.size() > 0 || pg.all_peers.size() > pg.target_set.size()))
+    if ((pg.state == PG_ACTIVE || pg.state == (PG_ACTIVE|PG_LEFT_ON_DEAD)) &&
+        (pg.target_history.size() != 1 ||
+        pg.target_history[0].osd_set != pg.target_set ||
+        pg.target_history[0].min_epoch != 0 ||
+        pg.target_history[0].max_epoch != pg.epoch ||
+        pg.all_peers.size() > count_nonzero_osds(pg.target_set)))
     {
         // Clear history of active+clean PGs
         pg.history_changed = true;
         pg.target_history.clear();
-        pg.all_peers = pg.target_set;
-        pg.cur_peers = pg.target_set;
-    }
-    else if (pg.state == (PG_ACTIVE|PG_LEFT_ON_DEAD))
-    {
-        // Clear history of active+left_on_dead PGs, but leave dead OSDs in all_peers
-        pg.history_changed = true;
-        pg.target_history.clear();
-        std::set<osd_num_t> dead_peers;
-        for (auto pg_osd: pg.all_peers)
+        pg.target_history.push_back((pg_history_set_t){
+            .osd_set = pg.cur_set,
+            .min_epoch = 0,
+            .max_epoch = pg.epoch,
+        });
+        if (pg.state == PG_ACTIVE)
         {
-            dead_peers.insert(pg_osd);
-        }
-        for (auto pg_osd: pg.cur_peers)
-        {
-            dead_peers.erase(pg_osd);
-        }
-        for (auto pg_osd: pg.target_set)
-        {
-            if (pg_osd)
+            pg.all_peers.clear();
+            for (auto pg_osd: pg.target_set)
             {
-                dead_peers.insert(pg_osd);
+                if (pg_osd)
+                    pg.all_peers.push_back(pg_osd);
             }
         }
-        pg.all_peers.clear();
-        pg.all_peers.insert(pg.all_peers.begin(), dead_peers.begin(), dead_peers.end());
+        else
+        {
+            // Clear history of active+left_on_dead PGs, but leave dead OSDs in all_peers
+            std::set<osd_num_t> dead_peers(pg.all_peers.begin(), pg.all_peers.end());
+            for (auto pg_osd: pg.cur_peers)
+            {
+                dead_peers.erase(pg_osd);
+            }
+            for (auto pg_osd: pg.target_set)
+            {
+                if (pg_osd)
+                    dead_peers.insert(pg_osd);
+            }
+            pg.all_peers.clear();
+            pg.all_peers.insert(pg.all_peers.begin(), dead_peers.begin(), dead_peers.end());
+        }
         pg.cur_peers.clear();
         for (auto pg_osd: pg.target_set)
         {
             if (pg_osd)
-            {
                 pg.cur_peers.push_back(pg_osd);
+        }
+    }
+    if (pg.history_changed)
+    {
+        bool epoch_already_reported = false;
+        int max_epoch_pos = -1;
+        for (int i = pg.target_history.size()-1; i >= 0; i--)
+        {
+            if (pg.target_history[i].min_epoch > pg.epoch)
+            {
+                printf("[PG %u/%u] Invalid PG history: there is an entry with min_epoch (%lu) > current epoch (%lu)\n",
+                    pg.pool_id, pg.pg_num, pg.target_history[i].min_epoch, pg.epoch);
+                force_stop(1);
+                return;
+            }
+            if (max_epoch_pos < 0 || pg.target_history[i].max_epoch > pg.target_history[max_epoch_pos].max_epoch)
+            {
+                max_epoch_pos = i;
+            }
+            if (pg.target_history[i].min_epoch <= pg.epoch &&
+                pg.target_history[i].max_epoch >= pg.epoch)
+            {
+                if (pg.target_history[i].osd_set != pg.cur_set)
+                {
+                    printf("[PG %u/%u] Invalid target_history: epoch %lu has another OSD set already registered\n", pg.pool_id, pg.pg_num, pg.epoch);
+                    force_stop(1);
+                    return;
+                }
+                // Already reported
+                epoch_already_reported = true;
+                break;
+            }
+        }
+        if (!epoch_already_reported)
+        {
+            if (max_epoch_pos >= 0 && pg.target_history[max_epoch_pos].osd_set == pg.cur_set)
+            {
+                pg.target_history[max_epoch_pos].max_epoch = pg.epoch;
+            }
+            else
+            {
+                pg.target_history.push_back((pg_history_set_t){
+                    .osd_set = pg.cur_set,
+                    .min_epoch = pg.epoch,
+                    .max_epoch = pg.epoch,
+                });
             }
         }
     }

src/osd_peering_pg.cpp

@@ -52,6 +52,7 @@ struct pg_obj_state_check_t
 
     void walk();
     void start_object();
+    void recheck_version_osd_set();
     void handle_version();
     void finish_object();
 };
@@ -84,27 +85,19 @@ void pg_obj_state_check_t::walk()
         pg->state = PG_INCOMPLETE | PG_HAS_INVALID;
         return;
     }
+    // Activate PG
     if (pg->pg_cursize < pg->pg_size)
     {
-        // Report PG history and activate
+        // History will be reported on first write
         pg->state |= PG_DEGRADED | PG_PEERED;
-        std::vector<osd_num_t> history_set;
-        for (auto peer_osd: pg->cur_set)
-        {
-            if (peer_osd != 0)
-            {
-                history_set.push_back(peer_osd);
-            }
-        }
-        pg->target_history.push_back(history_set);
-        pg->history_changed = true;
     }
     else
     {
-        // Just activate
         pg->state |= PG_ACTIVE;
+        // Clear history
+        pg->history_changed = true;
     }
-    if (pg->state == PG_ACTIVE && pg->cur_peers.size() < pg->all_peers.size())
+    if (pg->cur_peers.size() < pg->all_peers.size())
     {
         pg->state |= PG_LEFT_ON_DEAD;
     }
@@ -121,13 +114,82 @@ void pg_obj_state_check_t::start_object()
     n_unstable = n_invalid = 0;
 }
 
+void pg_obj_state_check_t::recheck_version_osd_set()
+{
+    uint64_t epoch = (last_ver >> (64-PG_EPOCH_BITS));
+    if (!pg->epoch_sizes_differ && n_copies >= pg->pg_size)
+    {
+        // Enough copies
+        return;
+    }
+    auto epoch_it = pg->target_by_epoch.lower_bound(epoch);
+    if (epoch_it == pg->target_by_epoch.end() || epoch_it->second.min_epoch > epoch)
+    {
+        // Epoch info not found
+        return;
+    }
+    if (pg->epoch_sizes_differ && n_copies >= epoch_it->second.osd_set.size())
+    {
+        // For the (unlikely) case of PG size change - enough copies
+        return;
+    }
+    // Recheck version against the OSD set corresponding to epoch if it's known
+    if (epoch_it != pg->target_by_epoch.end() && epoch_it->second.min_epoch <= epoch)
+    {
+        for (int j = 0; j < epoch_it->second.osd_set.size(); j++)
+        {
+            osd_num_t cur_osd = epoch_it->second.osd_set[j];
+            bool found = false;
+            for (int i = ver_start; i < ver_end; i++)
+            {
+                if (cur_osd == list[i].osd_num)
+                {
+                    found = true;
+                    break;
+                }
+            }
+            if (!found)
+            {
+                // Check if a newer version is present on the same OSD and masks the older one
+                // It happens for overwritten replicas in the following case:
+                // Version 1 is present on OSD 1,2,3
+                // Client tries to write Version 2
+                // OSD 3 succeeds to write Version 2, others don't. OSD 3 crashes, then starts again
+                // OSD 1 sees: version 1 on OSD 1,2 and version 2 on OSD 3
+                //   (version 1 on OSD 3 is already masked/removed)
+                // Version 1 is not present on a full set, but it must not be removed
+                if (replicated)
+                {
+                    for (int i = obj_start; i < ver_start; i++)
+                    {
+                        if (cur_osd == list[i].osd_num)
+                        {
+                            found = true;
+                            break;
+                        }
+                    }
+                }
+                if (!found)
+                {
+                    // Object is missing from one of the OSDs of that set.
+                    // This means it's deleted or moved and we can safely drop this version.
+                    target_ver = 0;
+                    break;
+                }
+            }
+        }
+    }
+}
+
 void pg_obj_state_check_t::handle_version()
 {
     if (!target_ver && last_ver != list[list_pos].version && (n_stable > 0 || n_roles >= pg->pg_data_size))
     {
         // Version is either stable or recoverable
-        target_ver = last_ver;
         ver_end = list_pos;
+        target_ver = last_ver;
+        // Skip versions that are not present on any of OSDs for the corresponding PG epoch
+        recheck_version_osd_set();
     }
     if (!target_ver)
     {
@@ -191,6 +253,8 @@ void pg_obj_state_check_t::finish_object()
         // Version is either stable or recoverable
         target_ver = last_ver;
         ver_end = list_pos;
+        // Skip versions that are not present on any of OSDs for the corresponding PG epoch
+        recheck_version_osd_set();
     }
     obj_end = list_pos;
     // Remember the decision
@@ -244,11 +308,23 @@ void pg_obj_state_check_t::finish_object()
             }
         }
     }
-    if (!target_ver)
+    if (!target_ver && (n_unstable >= obj_end-obj_start))
     {
         return;
     }
-    if (!replicated && n_roles < pg->pg_data_size)
+    if (!target_ver)
+    {
+        // Object is present, but should not be :) i.e. it's a deleted object that reappeared
+        if (log_level > 1)
+        {
+            printf("Object is deleted: %lx:%lx version=%lu/%lu\n", oid.inode, oid.stripe, target_ver, max_ver);
+        }
+        state = OBJ_DELETED;
+        pg->state = pg->state | PG_HAS_MISPLACED;
+        // To record all versions as outdated:
+        ver_end = obj_start;
+    }
+    else if (!replicated && n_roles < pg->pg_data_size)
     {
         if (log_level > 1)
         {
@@ -276,7 +352,7 @@ void pg_obj_state_check_t::finish_object()
         pg->state = pg->state | PG_HAS_MISPLACED;
     }
     if (log_level > 1 && (state & (OBJ_INCOMPLETE | OBJ_DEGRADED)) ||
-        log_level > 2 && (state & OBJ_MISPLACED))
+        log_level > 2 && (state & (OBJ_MISPLACED | OBJ_DELETED)))
     {
         for (int i = obj_start; i < obj_end; i++)
         {
@@ -285,9 +361,9 @@ void pg_obj_state_check_t::finish_object()
         }
     }
     pg->total_count++;
-    if (state != 0 || ver_end < obj_end)
+    osd_set.clear();
+    if (target_ver != 0 && (state != 0 || ver_end < obj_end))
     {
-        osd_set.clear();
         for (int i = ver_start; i < ver_end; i++)
         {
             osd_set.push_back((pg_obj_loc_t){
@@ -310,7 +386,8 @@ void pg_obj_state_check_t::finish_object()
                     break;
                 }
             }
-            if (j >= osd_set.size() && pg->cur_set[list[i].oid.stripe & STRIPE_MASK] != list[i].osd_num)
+            if (j >= osd_set.size() && ((state & OBJ_DELETED) ||
+                pg->cur_set[list[i].oid.stripe & STRIPE_MASK] != list[i].osd_num))
             {
                 osd_set.push_back((pg_obj_loc_t){
                     .role = (list[i].oid.stripe & STRIPE_MASK),
@@ -325,7 +402,11 @@ void pg_obj_state_check_t::finish_object()
             }
         }
     }
-    if (target_ver < max_ver)
+    if (state & OBJ_DELETED)
+    {
+        pg->ver_override[oid] = max_ver;
+    }
+    else if (target_ver < max_ver)
     {
         pg->ver_override[oid] = target_ver;
     }
@@ -379,6 +460,7 @@ void pg_obj_state_check_t::finish_object()
         }
         else
         {
+            assert(it->second.state == state);
             it->second.object_count++;
         }
         if (state & OBJ_INCOMPLETE)
@@ -399,6 +481,34 @@ void pg_obj_state_check_t::finish_object()
 // FIXME: Write at least some tests for this function
 void pg_t::calc_object_states(int log_level)
 {
+    // Calculate intersections of target_history with cur_peers
+    for (auto & history_item: target_history)
+    {
+        if (history_item.max_epoch)
+        {
+            pg_history_set_t & set_copy = target_by_epoch[history_item.max_epoch];
+            set_copy.min_epoch = history_item.min_epoch;
+            set_copy.max_epoch = history_item.max_epoch;
+            for (int i = 0; i < history_item.osd_set.size(); i++)
+            {
+                if (history_item.osd_set[i] != 0)
+                {
+                    for (int j = 0; j < cur_set.size(); j++)
+                    {
+                        if (cur_set[j] == history_item.osd_set[i])
+                        {
+                            set_copy.osd_set.push_back(history_item.osd_set[i]);
+                            break;
+                        }
+                    }
+                }
+            }
+            if (set_copy.osd_set.size() != pg_size)
+            {
+                epoch_sizes_differ = true;
+            }
+        }
+    }
     // Copy all object lists into one array
     pg_obj_state_check_t st;
     st.log_level = log_level;
@@ -435,10 +545,18 @@ void pg_t::calc_object_states(int log_level)
     std::sort(st.list.begin(), st.list.end());
     // Walk over it and check object states
     st.walk();
-    if (this->state & (PG_DEGRADED|PG_LEFT_ON_DEAD))
+    target_by_epoch.clear();
+    if (this->state != PG_ACTIVE)
     {
         assert(epoch != (((uint64_t)1 << PG_EPOCH_BITS)-1));
         epoch++;
+        for (auto & pgh: target_history)
+        {
+            if (epoch <= pgh.max_epoch)
+            {
+                epoch = pgh.max_epoch+1;
+            }
+        }
     }
 }
 

src/osd_peering_pg.h

@@ -89,7 +89,9 @@ struct pg_t
     // epoch number - should increase with each non-clean activation of the PG
     uint64_t epoch = 0, reported_epoch = 0;
     // target history and all potential peers
-    std::vector<std::vector<osd_num_t>> target_history;
+    std::vector<pg_history_set_t> target_history;
+    std::map<uint64_t, pg_history_set_t> target_by_epoch;
+    bool epoch_sizes_differ = false;
     std::vector<osd_num_t> all_peers;
     bool history_changed = false;
     // peer list from the last peering event

src/osd_primary.cpp

@@ -199,6 +199,21 @@ void osd_t::continue_primary_read(osd_op_t *cur_op)
         {
             // PG may be degraded or have misplaced objects
             op_data->prev_set = get_object_osd_set(pg, op_data->oid, pg.cur_set.data(), &op_data->object_state);
+            if (op_data->object_state && (op_data->object_state->state & OBJ_DELETED))
+            {
+                // Object is deleted, just return zeroes
+                cur_op->reply.rw.version = 0;
+                cur_op->reply.rw.bitmap_len = op_data->pg_data_size * clean_entry_bitmap_size;
+                uint64_t zero_len = cur_op->reply.rw.bitmap_len + cur_op->req.rw.len;
+                while (zero_len >= 0)
+                {
+                    uint64_t cur_zero_len = zero_buffer_size > zero_len ? zero_len : zero_buffer_size;
+                    cur_op->iov.push_back(zero_buffer, cur_zero_len);
+                    zero_len -= cur_zero_len;
+                }
+                finish_op(cur_op, cur_op->req.rw.len);
+                return;
+            }
         }
         if (pg.state == PG_ACTIVE || op_data->scheme == POOL_SCHEME_REPLICATED)
         {
@@ -290,7 +305,7 @@ void osd_t::remove_object_from_state(object_id & oid, pg_osd_set_state_t *object
             report_pg_state(pg);
         }
     }
-    else if (object_state->state & OBJ_MISPLACED)
+    else if (object_state->state & (OBJ_MISPLACED | OBJ_DELETED))
     {
         this->misplaced_objects--;
         pg.misplaced_objects.erase(oid);
@@ -329,12 +344,6 @@ void osd_t::continue_primary_del(osd_op_t *cur_op)
     else if (op_data->st == 4) goto resume_4;
     else if (op_data->st == 5) goto resume_5;
     assert(op_data->st == 0);
-    // Delete is forbidden even in active PGs if they're also degraded or have previous dead OSDs
-    if (pg.state & (PG_DEGRADED | PG_LEFT_ON_DEAD))
-    {
-        finish_op(cur_op, -EBUSY);
-        return;
-    }
     if (!check_write_queue(cur_op, pg))
     {
         return;
@@ -342,11 +351,18 @@ void osd_t::continue_primary_del(osd_op_t *cur_op)
 resume_1:
     // Determine which OSDs contain this object and delete it
     op_data->prev_set = get_object_osd_set(pg, op_data->oid, pg.cur_set.data(), &op_data->object_state);
-    // Submit 1 read to determine the actual version number
-    submit_primary_subops(SUBMIT_RMW_READ, UINT64_MAX, op_data->prev_set, cur_op);
+    if (op_data->object_state && (op_data->object_state->state & OBJ_DELETED))
+    {
+        op_data->fact_ver = pg.ver_override[op_data->oid];
+    }
+    else
+    {
+        // Submit 1 read to determine the actual version number
+        submit_primary_subops(SUBMIT_RMW_READ, UINT64_MAX, op_data->prev_set, cur_op);
 resume_2:
-    op_data->st = 2;
-    return;
+        op_data->st = 2;
+        return;
+    }
 resume_3:
     if (op_data->errors > 0)
     {

src/osd_primary_chain.cpp

@@ -133,6 +133,12 @@ int osd_t::collect_bitmap_requests(osd_op_t *cur_op, pg_t & pg, std::vector<bitm
         uint64_t target_version = vo_it != pg.ver_override.end() ? vo_it->second : UINT64_MAX;
         pg_osd_set_state_t *object_state;
         uint64_t* cur_set = get_object_osd_set(pg, cur_oid, pg.cur_set.data(), &object_state);
+        if (object_state && (object_state->state & OBJ_DELETED))
+        {
+            // Object is deleted, zero out the bitmap
+            memset((uint8_t*)op_data->snapshot_bitmaps + chain_num*clean_entry_bitmap_size, 0, clean_entry_bitmap_size);
+            continue;
+        }
         if (pg.scheme == POOL_SCHEME_REPLICATED)
         {
             osd_num_t read_target = 0;

src/osd_primary_subops.cpp

@@ -116,17 +116,19 @@ void osd_t::submit_primary_subops(int submit_type, uint64_t op_version, const ui
         if (osd_set[role] != 0 && (wr || !rep && stripes[role].read_end != 0))
             n_subops++;
     }
-    if (!n_subops && (submit_type == SUBMIT_RMW_READ || rep))
+    if (!n_subops && (submit_type == SUBMIT_RMW_READ || rep) && zero_read >= 0)
         n_subops = 1;
     else
         zero_read = -1;
-    osd_op_t *subops = new osd_op_t[n_subops];
     op_data->fact_ver = 0;
     op_data->done = op_data->errors = 0;
     op_data->n_subops = n_subops;
-    op_data->subops = subops;
-    int sent = submit_primary_subop_batch(submit_type, op_data->oid.inode, op_version, op_data->stripes, osd_set, cur_op, 0, zero_read);
-    assert(sent == n_subops);
+    if (n_subops > 0)
+    {
+        op_data->subops = new osd_op_t[n_subops];
+        int sent = submit_primary_subop_batch(submit_type, op_data->oid.inode, op_version, op_data->stripes, osd_set, cur_op, 0, zero_read);
+        assert(sent == n_subops);
+    }
 }
 
 int osd_t::submit_primary_subop_batch(int submit_type, inode_t inode, uint64_t op_version,

src/osd_primary_write.cpp

@@ -154,10 +154,9 @@ resume_3:
     if (pg.epoch > pg.reported_epoch)
     {
         // Report newer epoch before writing
-        // FIXME: We may report only one PG state here...
-        this->pg_state_dirty.insert({ .pool_id = pg.pool_id, .pg_num = pg.pg_num });
+        // FIXME: We don't have to report all changed PG states here
         pg.history_changed = true;
-        report_pg_states();
+        report_pg_state(pg);
 resume_10:
         if (pg.epoch > pg.reported_epoch)
         {

src/pg_states.h

@@ -34,6 +34,7 @@
 #define OBJ_DEGRADED 0x02
 #define OBJ_INCOMPLETE 0x04
 #define OBJ_MISPLACED 0x08
+#define OBJ_DELETED 0x10
 #define OBJ_NEEDS_STABLE 0x10000
 #define OBJ_NEEDS_ROLLBACK 0x20000
 

tests/run_3osds.sh

@@ -18,7 +18,7 @@ done
 cd mon
 npm install
 cd ..
-node mon/mon-main.js --etcd_url $ETCD_URL --etcd_prefix "/vitastor" &>./testdata/mon.log &
+node mon/mon-main.js --etcd_url $ETCD_URL --etcd_prefix "/vitastor" --verbose 1 &>./testdata/mon.log &
 MON_PID=$!
 
 if [ -n "$GLOBAL_CONF" ]; then
@@ -31,15 +31,31 @@ else
     $ETCDCTL put /vitastor/config/pools '{"1":{"name":"testpool","scheme":"xor","pg_size":'$PG_SIZE',"pg_minsize":'$PG_MINSIZE',"parity_chunks":1,"pg_count":'$PG_COUNT',"failure_domain":"osd"}}'
 fi
 
-sleep 3
+wait_up()
+{
+    local sec=$1
+    local i=0
+    local configured=0
+    while [[ $i -lt $sec ]]; do
+        if $ETCDCTL get /vitastor/config/pgs --print-value-only | jq -s -e '(. | length) != 0 and ([ .[0].items["1"][] |
+            select(((.osd_set | select(. != 0) | sort | unique) | length) == '$PG_SIZE') ] | length) == '$PG_COUNT; then
+            configured=1
+            if $ETCDCTL get /vitastor/pg/state/1/ --prefix --print-value-only | jq -s -e '[ .[] | select(.state == ["active"]) ] | length == '$PG_COUNT; then
+                break
+            fi
+        fi
+        sleep 1
+        i=$((i+1))
+        if [ $i -eq $sec ]; then
+            if [[ $configured -ne 0 ]]; then
+                format_error "FAILED: $PG_COUNT PG(s) NOT CONFIGURED"
+            fi
+            format_error "FAILED: $PG_COUNT PG(s) NOT UP"
+        fi
+    done
+}
 
-if ! ($ETCDCTL get /vitastor/config/pgs --print-value-only | jq -s -e '(. | length) != 0 and ([ .[0].items["1"][] | select(((.osd_set | select(. != 0) | sort | unique) | length) == '$PG_SIZE') ] | length) == '$PG_COUNT); then
-    format_error "FAILED: $PG_COUNT PG(s) NOT CONFIGURED"
-fi
-
-if ! ($ETCDCTL get /vitastor/pg/state/1/ --prefix --print-value-only | jq -s -e '[ .[] | select(.state == ["active"]) ] | length == '$PG_COUNT); then
-    format_error "FAILED: $PG_COUNT PG(s) NOT UP"
-fi
+wait_up 60
 
 if ! cmp build/src/block-vitastor.so /usr/lib/x86_64-linux-gnu/qemu/block-vitastor.so; then
     sudo rm -f /usr/lib/x86_64-linux-gnu/qemu/block-vitastor.so

tests/run_7osds.sh

@@ -65,10 +65,10 @@ wait_finish_rebalance()
     while [[ $i -lt $sec ]]; do
         ($ETCDCTL get --prefix /vitastor/pg/state/ --print-value-only | jq -s -e '([ .[] | select(.state == ["active"]) ] | length) == 32') && \
             break
-        if [ $i -eq 60 ]; then
-            format_error "Rebalance couldn't finish in $sec seconds"
-        fi
         sleep 1
         i=$((i+1))
+        if [ $i -eq $sec ]; then
+            format_error "Rebalance couldn't finish in $sec seconds"
+        fi
     done
 }

tests/run_tests.sh

@@ -12,6 +12,8 @@ EC=1 ./test_change_pg_count.sh
 
 ./test_change_pg_size.sh
 
+./test_degraded_delete.sh
+
 ./test_etcd_fail.sh
 
 ./test_failure_domain.sh

tests/test_degraded_delete.sh

@@ -0,0 +1,131 @@
+#!/bin/bash -ex
+
+# Run 3 OSDs
+
+. `dirname $0`/run_3osds.sh
+
+# Write inodes 1 and 2
+
+LD_PRELOAD="build/src/libfio_vitastor.so" \
+    fio -thread -name=test -ioengine=build/src/libfio_vitastor.so -bs=1M -direct=1 -iodepth=4 \
+        -rw=write -etcd=$ETCD_URL -pool=1 -inode=1 -size=128M -runtime=10
+
+LD_PRELOAD="build/src/libfio_vitastor.so" \
+    fio -thread -name=test -ioengine=build/src/libfio_vitastor.so -bs=1M -direct=1 -iodepth=4 \
+        -rw=write -etcd=$ETCD_URL -pool=1 -inode=2 -size=128M -runtime=10
+
+LD_PRELOAD="build/src/libfio_vitastor.so" \
+    fio -thread -name=test -ioengine=build/src/libfio_vitastor.so -bs=4k -direct=1 -iodepth=16 \
+        -rw=randwrite -etcd=$ETCD_URL -pool=1 -inode=1 -size=128M -runtime=10 &>/dev/null &
+
+sleep 5
+
+# Stop OSD 1
+
+kill -INT $OSD1_PID
+sleep 2
+
+# Remove inode 2
+
+build/src/vitastor-cli rm-data --etcd_address $ETCD_URL --pool 1 --inode 2
+
+# Run 3 more OSDs and move PG to 4,5,6
+
+for i in $(seq 4 6); do
+    dd if=/dev/zero of=./testdata/test_osd$i.bin bs=1024 count=1 seek=$((OSD_SIZE*1024-1))
+    build/src/vitastor-osd --osd_num $i --bind_address 127.0.0.1 $OSD_ARGS --etcd_address $ETCD_URL $(build/src/vitastor-cli simple-offsets --format options ./testdata/test_osd$i.bin 2>/dev/null) &>./testdata/osd$i.log &
+    eval OSD${i}_PID=$!
+done
+
+$ETCDCTL put /vitastor/config/osd/1 '{"reweight":0}'
+$ETCDCTL put /vitastor/config/osd/2 '{"reweight":0}'
+$ETCDCTL put /vitastor/config/osd/3 '{"reweight":0}'
+
+# Wait for rebalance to finish
+
+wait_finish_rebalance()
+{
+    local sec=$1
+    local st=$2
+    local i=0
+    while [[ $i -lt $sec ]]; do
+        if $ETCDCTL get --prefix /vitastor/pg/state/ --print-value-only | jq -s -e \
+            '([ .[] | select(.state == ['$st'] and (.peers | contains([1]) | not) and (.peers | contains([2,3]) | not)) ] | length) == '$PG_COUNT; then
+            break
+        fi
+        sleep 1
+        i=$((i+1))
+        if [ $i -eq $sec ]; then
+            format_error "Rebalance couldn't finish in $sec seconds"
+        fi
+    done
+}
+
+wait_finish_rebalance 60 '"active","left_on_dead"'
+
+# Stop OSD 2,3
+
+kill -INT $OSD2_PID
+kill -INT $OSD3_PID
+sleep 2
+
+# Verify that PGs are still active
+
+if ! ($ETCDCTL get /vitastor/pg/state/1/ --prefix --print-value-only | jq -s -e '[ .[] | select(.state == ["active","left_on_dead"]) ] | length == '$PG_COUNT); then
+    format_error "FAILED: $PG_COUNT PG(s) NOT UP"
+fi
+
+# Start OSD 1
+
+build/src/vitastor-osd --osd_num 1 --bind_address 127.0.0.1 $OSD_ARGS --etcd_address $ETCD_URL $(build/src/vitastor-cli simple-offsets --format options ./testdata/test_osd1.bin 2>/dev/null) &>./testdata/osd1.log &
+OSD1_PID=$!
+
+# Verify that inode 2 is removed and inode 1 is in place
+
+wait_repeer_1()
+{
+    local sec=$1
+    local i=0
+    while [[ $i -lt $sec ]]; do
+        if grep -q 'Repeer because of OSD 1' testdata/osd4.log testdata/osd5.log testdata/osd6.log; then
+            break
+        fi
+        sleep 1
+        i=$((i+1))
+        if [ $i -eq $sec ]; then
+            format_error "OSD 4/5/6 do not peer with older OSD 1"
+        fi
+    done
+}
+
+wait_repeer_1 15
+
+wait_finish_rebalance 15 '"active"'
+
+if [ "$SCHEME" = "replicated" ]; then
+    NOBJ=1024
+else
+    NOBJ=$((1024/(PG_SIZE-1)))
+fi
+
+if ! ($ETCDCTL get /vitastor/pg/stats/1/1 --print-value-only | jq -s -e '.[0].object_count == '$NOBJ); then
+    format_error "FAILED: PG SHOULD CONTAIN EXACTLY 128 MB OF DATA, BUT IT DOESN'T"
+fi
+
+qemu-img convert -S 4096 -p \
+    -f raw "vitastor:etcd_host=127.0.0.1\:$ETCD_PORT/v3:pool=1:inode=1:size=4096" \
+    -O raw ./testdata/inode1.bin
+
+qemu-img convert -S 4096 -p \
+    -f raw "vitastor:etcd_host=127.0.0.1\:$ETCD_PORT/v3:pool=1:inode=2:size="$((128*1024*1024)) \
+    -O raw ./testdata/inode2.bin
+
+if (dd if=/dev/zero bs=4096 count=1 | diff - ./testdata/inode1.bin); then
+    format_error "FAILED: INODE 1 SEEMS LOST"
+fi
+
+if ! (dd if=/dev/zero bs=1M count=128 | diff - ./testdata/inode2.bin); then
+    format_error "FAILED: INODE 2 SEEMS RESTORED"
+fi
+
+format_green OK