Fix metadata area size calculation, print free space, wait for free space

FIXME: Now it crashes with -ENOSPC on linear overwrite

allocator.cpp

@@ -19,7 +19,7 @@ allocator::allocator(uint64_t blocks)
     total -= p2;
     total += (blocks+63) / 64;
     mask = new uint64_t[2 + total];
-    size = blocks;
+    size = free = blocks;
     last_one_mask = (blocks % 64) == 0
         ? UINT64_MAX
         : ~(UINT64_MAX << (64 - blocks % 64));
@@ -55,6 +55,10 @@ void allocator::set(uint64_t addr, bool value)
         uint64_t bit = cur_addr % 64;
         if (((mask[last] >> bit) & 1) != value64)
         {
+            if (is_last)
+            {
+                free += value ? -1 : 1;
+            }
             if (value)
             {
                 mask[last] = mask[last] | (1l << bit);
@@ -120,3 +124,8 @@ uint64_t allocator::find_free()
     }
     return addr;
 }
+
+uint64_t allocator::get_free_count()
+{
+    return free;
+}

allocator.h

@@ -6,6 +6,7 @@
 class allocator
 {
     uint64_t size;
+    uint64_t free;
     uint64_t last_one_mask;
     uint64_t *mask;
 public:
@@ -13,4 +14,5 @@ public:
     ~allocator();
     void set(uint64_t addr, bool value);
     uint64_t find_free();
+    uint64_t get_free_count();
 };

blockstore.cpp

@@ -260,6 +260,14 @@ void blockstore::check_wait(blockstore_operation *op)
         }
         op->wait_for = 0;
     }
+    else if (op->wait_for == WAIT_FREE)
+    {
+        if (!data_alloc->get_free_count() && !flusher->is_active())
+        {
+            return;
+        }
+        op->wait_for = 0;
+    }
     else
     {
         throw std::runtime_error("BUG: op->wait_for value is unexpected");

blockstore.h

@@ -198,6 +198,8 @@ public:
 #define WAIT_JOURNAL 3
 // Suspend operation until the next journal sector buffer is free
 #define WAIT_JOURNAL_BUFFER 4
+// Suspend operation until there is some free space on the data device
+#define WAIT_FREE 5
 
 struct blockstore_operation
 {

blockstore_init.cpp

@@ -72,7 +72,7 @@ int blockstore_init_meta::loop()
         }
     }
     // metadata read finished
-    printf("Metadata entries loaded: %d\n", entries_loaded);
+    printf("Metadata entries loaded: %lu, free blocks: %lu / %lu\n", entries_loaded, bs->data_alloc->get_free_count(), bs->block_count);
     free(metadata_buffer);
     metadata_buffer = NULL;
     return 0;
@@ -93,10 +93,9 @@ void blockstore_init_meta::handle_entries(struct clean_disk_entry* entries, int
                 if (clean_it != bs->clean_db.end())
                 {
                     // free the previous block
-                    bs->data_alloc->set(clean_it->second.version >> block_order, false);
+                    bs->data_alloc->set(clean_it->second.location >> block_order, false);
                 }
-                else
-                    entries_loaded++;
+                entries_loaded++;
                 bs->data_alloc->set(done_cnt+i, true);
                 bs->clean_db[entries[i].oid] = (struct clean_entry){
                     .version = entries[i].version,
@@ -287,7 +286,7 @@ resume_1:
             }
         }
     }
-    printf("Journal entries loaded: %d\n", entries_loaded);
+    printf("Journal entries loaded: %lu, free blocks: %lu / %lu\n", entries_loaded, bs->data_alloc->get_free_count(), bs->block_count);
     if (!bs->journal.inmemory)
     {
         free(journal_buffer);
@@ -397,6 +396,7 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t len)
                     .len = bs->block_size,
                     .journal_sector = proc_pos,
                 });
+                bs->data_alloc->set(je->big_write.location >> bs->block_order, true);
                 bs->journal.used_sectors[proc_pos]++;
                 auto & unstab = bs->unstable_writes[ov.oid];
                 unstab = unstab < ov.version ? ov.version : unstab;

blockstore_init.h

@@ -7,7 +7,7 @@ class blockstore_init_meta
     uint8_t *metadata_buffer = NULL;
     uint64_t metadata_read = 0;
     int prev = 0, prev_done = 0, done_len = 0, submitted = 0, done_cnt = 0;
-    int entries_loaded = 0;
+    uint64_t entries_loaded = 0;
     struct io_uring_sqe *sqe;
     struct ring_data_t *data;
     void handle_entries(struct clean_disk_entry* entries, int count, int block_order);
@@ -21,7 +21,7 @@ class blockstore_init_journal
 {
     blockstore *bs;
     int wait_state = 0, wait_count = 0;
-    int entries_loaded = 0;
+    uint64_t entries_loaded = 0;
     void *journal_buffer = NULL;
     uint32_t crc32_last = 0;
     bool started = false;

blockstore_open.cpp

@@ -37,7 +37,7 @@ void blockstore::calc_lengths(blockstore_config_t & config)
     }
     // required metadata size
     block_count = data_len / block_size;
-    meta_len = (block_count / (512 / sizeof(clean_disk_entry))) * 512;
+    meta_len = ((block_count - 1 + 512 / sizeof(clean_disk_entry)) / (512 / sizeof(clean_disk_entry))) * 512;
     if (meta_area < meta_len)
     {
         throw std::runtime_error("Metadata area is too small");

blockstore_write.cpp

@@ -49,7 +49,6 @@ void blockstore::enqueue_write(blockstore_operation *op)
 // First step of the write algorithm: dequeue operation and submit initial write(s)
 int blockstore::dequeue_write(blockstore_operation *op)
 {
-    auto cb = [this, op](ring_data_t *data) { handle_write_event(data, op); };
     auto dirty_it = dirty_db.find((obj_ver_id){
         .oid = op->oid,
         .version = op->version,
@@ -61,6 +60,12 @@ int blockstore::dequeue_write(blockstore_operation *op)
         if (loc == UINT64_MAX)
         {
             // no space
+            if (flusher->is_active())
+            {
+                // hope that some space will be available after flush
+                op->wait_for = WAIT_FREE;
+                return 0;
+            }
             op->retval = -ENOSPC;
             op->callback(op);
             return 1;
@@ -87,7 +92,7 @@ int blockstore::dequeue_write(blockstore_operation *op)
             op->iov_zerofill[0] = (struct iovec){ op->buf, op->len };
             data->iov.iov_len = op->len; // to check it in the callback
         }
-        data->callback = cb;
+        data->callback = [this, op](ring_data_t *data) { handle_write_event(data, op); };
         my_uring_prep_writev(
             sqe, data_fd, op->iov_zerofill, vcnt, data_offset + (loc << block_order)
         );
@@ -134,6 +139,7 @@ int blockstore::dequeue_write(blockstore_operation *op)
         je->crc32_data = crc32c(0, op->buf, op->len);
         je->crc32 = je_crc32((journal_entry*)je);
         journal.crc32_last = je->crc32;
+        auto cb = [this, op](ring_data_t *data) { handle_write_event(data, op); };
         prepare_journal_sector_write(journal, sqe1, cb);
         op->min_used_journal_sector = op->max_used_journal_sector = 1 + journal.cur_sector;
         // Prepare journal data write