Implement offline TRIM support

src/disk_tool/disk_tool_discard.cpp

@@ -0,0 +1,89 @@
+// Copyright (c) Vitaliy Filippov, 2019+
+// License: VNPL-1.1 (see README.md for details)
+
+#include "disk_tool.h"
+#include "str_util.h"
+#include "json_util.h"
+
+int disk_tool_t::trim_data(std::string device)
+{
+    int r;
+    // Parse parameters
+    if (stoull_full(device))
+        device = "/dev/vitastor/osd"+device+"-data";
+    json11::Json sb = read_osd_superblock(device, true, false);
+    if (sb.is_null())
+        return 1;
+    auto sb_params = json_to_string_map(sb["params"].object_items());
+    if (options["discard_granularity"] != "")
+        sb_params["discard_granularity"] = options["discard_granularity"];
+    if (options["min_discard_size"] != "")
+        sb_params["min_discard_size"] = options["min_discard_size"];
+    try
+    {
+        dsk.parse_config(sb_params);
+    }
+    catch (std::exception & e)
+    {
+        fprintf(stderr, "Error: %s\n", e.what());
+        return 1;
+    }
+    if (!dsk.discard_granularity && sb["real_data_device"].string_value().substr(0, 5) == "/dev/")
+    {
+        auto dg = read_file("/sys/block/"+sb["real_data_device"].string_value().substr(5)+"/queue/discard_granularity", true);
+        if (dg != "")
+            dsk.discard_granularity = parse_size(trim(dg));
+    }
+    // Open devices
+    try
+    {
+        if (options["io"] != "")
+            dsk.data_io = dsk.meta_io = dsk.journal_io = options["io"];
+        dsk.open_data();
+        dsk.open_meta();
+        dsk.open_journal();
+        dsk.calc_lengths();
+    }
+    catch (std::exception & e)
+    {
+        dsk.close_all();
+        fprintf(stderr, "Error: %s\n", e.what());
+        return 1;
+    }
+    // Fill allocator
+    fprintf(stderr, "Reading metadata\n");
+    data_alloc = new allocator_t(dsk.block_count);
+    r = process_meta(
+        [this](blockstore_meta_header_v2_t *hdr) {},
+        [this](uint64_t block_num, clean_disk_entry *entry, uint8_t *bitmap)
+        {
+            data_alloc->set(block_num, true);
+        },
+        false
+    );
+    if (r != 0)
+    {
+        dsk.close_all();
+        return r;
+    }
+    fprintf(stderr, "Reading journal\n");
+    r = process_journal([this](void *buf)
+    {
+        return process_journal_block(buf, [this](int num, journal_entry *je)
+        {
+            if (je->type == JE_BIG_WRITE || je->type == JE_BIG_WRITE_INSTANT)
+            {
+                data_alloc->set(je->big_write.location / dsk.data_block_size, true);
+            }
+        });
+    }, false);
+    if (r != 0)
+    {
+        dsk.close_all();
+        return r;
+    }
+    // Trim
+    r = dsk.trim_data(data_alloc);
+    dsk.close_all();
+    return r == 0;
+}