diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 579ea7f8..0e225922 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -64,7 +64,7 @@ include_directories(
 
 # libvitastor_blk.so
 add_library(vitastor_blk SHARED
-	allocator.cpp blockstore.cpp blockstore_impl.cpp blockstore_init.cpp blockstore_open.cpp blockstore_journal.cpp blockstore_read.cpp
+	allocator.cpp blockstore.cpp blockstore_impl.cpp blockstore_disk.cpp blockstore_init.cpp blockstore_open.cpp blockstore_journal.cpp blockstore_read.cpp
 	blockstore_write.cpp blockstore_sync.cpp blockstore_stable.cpp blockstore_rollback.cpp blockstore_flush.cpp crc32c.c ringloop.cpp
 )
 target_link_libraries(vitastor_blk
diff --git a/src/blockstore_disk.cpp b/src/blockstore_disk.cpp
new file mode 100644
index 00000000..422f2626
--- /dev/null
+++ b/src/blockstore_disk.cpp
@@ -0,0 +1,322 @@
+// Copyright (c) Vitaliy Filippov, 2019+
+// License: VNPL-1.1 (see README.md for details)
+
+#include <sys/file.h>
+
+#include <stdexcept>
+
+#include "blockstore_impl.h"
+#include "blockstore_disk.h"
+
+static uint32_t is_power_of_two(uint64_t value)
+{
+    uint32_t l = 0;
+    while (value > 1)
+    {
+        if (value & 1)
+        {
+            return 64;
+        }
+        value = value >> 1;
+        l++;
+    }
+    return l;
+}
+
+void blockstore_disk_t::parse_config(std::map<std::string, std::string> & config)
+{
+    // Parse
+    if (config["disable_device_lock"] == "true" || config["disable_device_lock"] == "1" || config["disable_device_lock"] == "yes")
+    {
+        disable_flock = true;
+    }
+    cfg_journal_size = strtoull(config["journal_size"].c_str(), NULL, 10);
+    data_device = config["data_device"];
+    data_offset = strtoull(config["data_offset"].c_str(), NULL, 10);
+    cfg_data_size = strtoull(config["data_size"].c_str(), NULL, 10);
+    meta_device = config["meta_device"];
+    meta_offset = strtoull(config["meta_offset"].c_str(), NULL, 10);
+    data_block_size = strtoull(config["block_size"].c_str(), NULL, 10);
+    journal_device = config["journal_device"];
+    journal_offset = strtoull(config["journal_offset"].c_str(), NULL, 10);
+    disk_alignment = strtoull(config["disk_alignment"].c_str(), NULL, 10);
+    journal_block_size = strtoull(config["journal_block_size"].c_str(), NULL, 10);
+    meta_block_size = strtoull(config["meta_block_size"].c_str(), NULL, 10);
+    bitmap_granularity = strtoull(config["bitmap_granularity"].c_str(), NULL, 10);
+    // Validate
+    if (!data_block_size)
+    {
+        data_block_size = (1 << DEFAULT_DATA_BLOCK_ORDER);
+    }
+    if ((block_order = is_power_of_two(data_block_size)) >= 64 || data_block_size < MIN_DATA_BLOCK_SIZE || data_block_size >= MAX_DATA_BLOCK_SIZE)
+    {
+        throw std::runtime_error("Bad block size");
+    }
+    if (!disk_alignment)
+    {
+        disk_alignment = 4096;
+    }
+    else if (disk_alignment % DIRECT_IO_ALIGNMENT)
+    {
+        throw std::runtime_error("disk_alignment must be a multiple of "+std::to_string(DIRECT_IO_ALIGNMENT));
+    }
+    if (!journal_block_size)
+    {
+        journal_block_size = 4096;
+    }
+    else if (journal_block_size % DIRECT_IO_ALIGNMENT)
+    {
+        throw std::runtime_error("journal_block_size must be a multiple of "+std::to_string(DIRECT_IO_ALIGNMENT));
+    }
+    if (!meta_block_size)
+    {
+        meta_block_size = 4096;
+    }
+    else if (meta_block_size % DIRECT_IO_ALIGNMENT)
+    {
+        throw std::runtime_error("meta_block_size must be a multiple of "+std::to_string(DIRECT_IO_ALIGNMENT));
+    }
+    if (data_offset % disk_alignment)
+    {
+        throw std::runtime_error("data_offset must be a multiple of disk_alignment = "+std::to_string(disk_alignment));
+    }
+    if (!bitmap_granularity)
+    {
+        bitmap_granularity = DEFAULT_BITMAP_GRANULARITY;
+    }
+    else if (bitmap_granularity % disk_alignment)
+    {
+        throw std::runtime_error("Sparse write tracking granularity must be a multiple of disk_alignment = "+std::to_string(disk_alignment));
+    }
+    if (data_block_size % bitmap_granularity)
+    {
+        throw std::runtime_error("Block size must be a multiple of sparse write tracking granularity");
+    }
+    if (journal_device == meta_device || meta_device == "" && journal_device == data_device)
+    {
+        journal_device = "";
+    }
+    if (meta_device == data_device)
+    {
+        meta_device = "";
+    }
+    if (meta_offset % meta_block_size)
+    {
+        throw std::runtime_error("meta_offset must be a multiple of meta_block_size = "+std::to_string(meta_block_size));
+    }
+    if (journal_offset % journal_block_size)
+    {
+        throw std::runtime_error("journal_offset must be a multiple of journal_block_size = "+std::to_string(journal_block_size));
+    }
+    clean_entry_bitmap_size = data_block_size / bitmap_granularity / 8;
+    clean_entry_size = sizeof(clean_disk_entry) + 2*clean_entry_bitmap_size;
+}
+
+void blockstore_disk_t::calc_lengths()
+{
+    // data
+    data_len = data_device_size - data_offset;
+    if (data_fd == meta_fd && data_offset < meta_offset)
+    {
+        data_len = meta_offset - data_offset;
+    }
+    if (data_fd == journal_fd && data_offset < journal_offset)
+    {
+        data_len = data_len < journal_offset-data_offset
+            ? data_len : journal_offset-data_offset;
+    }
+    if (cfg_data_size != 0)
+    {
+        if (data_len < cfg_data_size)
+        {
+            throw std::runtime_error("Data area ("+std::to_string(data_len)+
+                " bytes) is smaller than configured size ("+std::to_string(cfg_data_size)+" bytes)");
+        }
+        data_len = cfg_data_size;
+    }
+    // meta
+    uint64_t meta_area_size = (meta_fd == data_fd ? data_device_size : meta_device_size) - meta_offset;
+    if (meta_fd == data_fd && meta_offset <= data_offset)
+    {
+        meta_area_size = data_offset - meta_offset;
+    }
+    if (meta_fd == journal_fd && meta_offset <= journal_offset)
+    {
+        meta_area_size = meta_area_size < journal_offset-meta_offset
+            ? meta_area_size : journal_offset-meta_offset;
+    }
+    // journal
+    journal_len = (journal_fd == data_fd ? data_device_size : (journal_fd == meta_fd ? meta_device_size : journal_device_size)) - journal_offset;
+    if (journal_fd == data_fd && journal_offset <= data_offset)
+    {
+        journal_len = data_offset - journal_offset;
+    }
+    if (journal_fd == meta_fd && journal_offset <= meta_offset)
+    {
+        journal_len = journal_len < meta_offset-journal_offset
+            ? journal_len : meta_offset-journal_offset;
+    }
+    // required metadata size
+    block_count = data_len / data_block_size;
+    meta_len = (1 + (block_count - 1 + meta_block_size / clean_entry_size) / (meta_block_size / clean_entry_size)) * meta_block_size;
+    if (meta_area_size < meta_len)
+    {
+        throw std::runtime_error("Metadata area is too small, need at least "+std::to_string(meta_len)+" bytes");
+    }
+    // requested journal size
+    if (cfg_journal_size > journal_len)
+    {
+        throw std::runtime_error("Requested journal_size is too large");
+    }
+    else if (cfg_journal_size > 0)
+    {
+        journal_len = cfg_journal_size;
+    }
+    if (journal_len < MIN_JOURNAL_SIZE)
+    {
+        throw std::runtime_error("Journal is too small, need at least "+std::to_string(MIN_JOURNAL_SIZE)+" bytes");
+    }
+}
+
+static void check_size(int fd, uint64_t *size, uint64_t *sectsize, std::string name)
+{
+    int sect;
+    struct stat st;
+    if (fstat(fd, &st) < 0)
+    {
+        throw std::runtime_error("Failed to stat "+name);
+    }
+    if (S_ISREG(st.st_mode))
+    {
+        *size = st.st_size;
+        if (sectsize)
+        {
+            *sectsize = st.st_blksize;
+        }
+    }
+    else if (S_ISBLK(st.st_mode))
+    {
+        if (ioctl(fd, BLKGETSIZE64, size) < 0 ||
+            ioctl(fd, BLKSSZGET, &sect) < 0)
+        {
+            throw std::runtime_error("Failed to get "+name+" size or block size: "+strerror(errno));
+        }
+        if (sectsize)
+        {
+            *sectsize = sect;
+        }
+    }
+    else
+    {
+        throw std::runtime_error(name+" is neither a file nor a block device");
+    }
+}
+
+void blockstore_disk_t::open_data()
+{
+    data_fd = open(data_device.c_str(), O_DIRECT|O_RDWR);
+    if (data_fd == -1)
+    {
+        throw std::runtime_error("Failed to open data device");
+    }
+    check_size(data_fd, &data_device_size, &data_device_sect, "data device");
+    if (disk_alignment % data_device_sect)
+    {
+        throw std::runtime_error(
+            "disk_alignment ("+std::to_string(disk_alignment)+
+            ") is not a multiple of data device sector size ("+std::to_string(data_device_sect)+")"
+        );
+    }
+    if (data_offset >= data_device_size)
+    {
+        throw std::runtime_error("data_offset exceeds device size = "+std::to_string(data_device_size));
+    }
+    if (!disable_flock && flock(data_fd, LOCK_EX|LOCK_NB) != 0)
+    {
+        throw std::runtime_error(std::string("Failed to lock data device: ") + strerror(errno));
+    }
+}
+
+void blockstore_disk_t::open_meta()
+{
+    if (meta_device != "")
+    {
+        meta_offset = 0;
+        meta_fd = open(meta_device.c_str(), O_DIRECT|O_RDWR);
+        if (meta_fd == -1)
+        {
+            throw std::runtime_error("Failed to open metadata device");
+        }
+        check_size(meta_fd, &meta_device_size, &meta_device_sect, "metadata device");
+        if (meta_offset >= meta_device_size)
+        {
+            throw std::runtime_error("meta_offset exceeds device size = "+std::to_string(meta_device_size));
+        }
+        if (!disable_flock && flock(meta_fd, LOCK_EX|LOCK_NB) != 0)
+        {
+            throw std::runtime_error(std::string("Failed to lock metadata device: ") + strerror(errno));
+        }
+    }
+    else
+    {
+        meta_fd = data_fd;
+        meta_device_sect = data_device_sect;
+        meta_device_size = 0;
+        if (meta_offset >= data_device_size)
+        {
+            throw std::runtime_error("meta_offset exceeds device size = "+std::to_string(data_device_size));
+        }
+    }
+    if (meta_block_size % meta_device_sect)
+    {
+        throw std::runtime_error(
+            "meta_block_size ("+std::to_string(meta_block_size)+
+            ") is not a multiple of data device sector size ("+std::to_string(meta_device_sect)+")"
+        );
+    }
+}
+
+void blockstore_disk_t::open_journal()
+{
+    if (journal_device != "")
+    {
+        journal_fd = open(journal_device.c_str(), O_DIRECT|O_RDWR);
+        if (journal_fd == -1)
+        {
+            throw std::runtime_error("Failed to open journal device");
+        }
+        check_size(journal_fd, &journal_device_size, &journal_device_sect, "journal device");
+        if (!disable_flock && flock(journal_fd, LOCK_EX|LOCK_NB) != 0)
+        {
+            throw std::runtime_error(std::string("Failed to lock journal device: ") + strerror(errno));
+        }
+    }
+    else
+    {
+        journal_fd = meta_fd;
+        journal_device_sect = meta_device_sect;
+        journal_device_size = 0;
+        if (journal_offset >= data_device_size)
+        {
+            throw std::runtime_error("journal_offset exceeds device size");
+        }
+    }
+    if (journal_block_size % journal_device_sect)
+    {
+        throw std::runtime_error(
+            "journal_block_size ("+std::to_string(journal_block_size)+
+            ") is not a multiple of journal device sector size ("+std::to_string(journal_device_sect)+")"
+        );
+    }
+}
+
+void blockstore_disk_t::close_all()
+{
+    if (data_fd >= 0)
+        close(data_fd);
+    if (meta_fd >= 0 && meta_fd != data_fd)
+        close(meta_fd);
+    if (journal_fd >= 0 && journal_fd != meta_fd)
+        close(journal_fd);
+    data_fd = meta_fd = journal_fd = -1;
+}
diff --git a/src/blockstore_disk.h b/src/blockstore_disk.h
new file mode 100644
index 00000000..eb356a41
--- /dev/null
+++ b/src/blockstore_disk.h
@@ -0,0 +1,42 @@
+// Copyright (c) Vitaliy Filippov, 2019+
+// License: VNPL-1.1 (see README.md for details)
+
+#pragma once
+
+#include <stdint.h>
+
+#include <string>
+#include <map>
+
+struct blockstore_disk_t
+{
+    std::string data_device, meta_device, journal_device;
+    uint32_t data_block_size;
+    uint64_t cfg_journal_size, cfg_data_size;
+    // Required write alignment and journal/metadata/data areas' location alignment
+    uint32_t disk_alignment = 4096;
+    // Journal block size - minimum_io_size of the journal device is the best choice
+    uint64_t journal_block_size = 4096;
+    // Metadata block size - minimum_io_size of the metadata device is the best choice
+    uint64_t meta_block_size = 4096;
+    // Sparse write tracking granularity. 4 KB is a good choice. Must be a multiple of disk_alignment
+    uint64_t bitmap_granularity = 4096;
+    // By default, Blockstore locks all opened devices exclusively. This option can be used to disable locking
+    bool disable_flock = false;
+
+    int meta_fd = -1, data_fd = -1, journal_fd = -1;
+    uint64_t meta_offset, meta_device_sect, meta_device_size, meta_len;
+    uint64_t data_offset, data_device_sect, data_device_size, data_len;
+    uint64_t journal_offset, journal_device_sect, journal_device_size, journal_len;
+
+    uint32_t block_order;
+    uint64_t block_count;
+    uint32_t clean_entry_bitmap_size = 0, clean_entry_size = 0;
+
+    void parse_config(std::map<std::string, std::string> & config);
+    void open_data();
+    void open_meta();
+    void open_journal();
+    void calc_lengths();
+    void close_all();
+};
diff --git a/src/blockstore_flush.cpp b/src/blockstore_flush.cpp
index 7fcbc745..36aff9ab 100644
--- a/src/blockstore_flush.cpp
+++ b/src/blockstore_flush.cpp
@@ -15,11 +15,11 @@ journal_flusher_t::journal_flusher_t(blockstore_impl_t *bs)
     active_flushers = 0;
     syncing_flushers = 0;
     // FIXME: allow to configure flusher_start_threshold and journal_trim_interval
-    flusher_start_threshold = bs->journal_block_size / sizeof(journal_entry_stable);
+    flusher_start_threshold = bs->dsk.journal_block_size / sizeof(journal_entry_stable);
     journal_trim_interval = 512;
     journal_trim_counter = bs->journal.flush_journal ? 1 : 0;
     trim_wanted = bs->journal.flush_journal ? 1 : 0;
-    journal_superblock = bs->journal.inmemory ? bs->journal.buffer : memalign_or_die(MEM_ALIGNMENT, bs->journal_block_size);
+    journal_superblock = bs->journal.inmemory ? bs->journal.buffer : memalign_or_die(MEM_ALIGNMENT, bs->dsk.journal_block_size);
     co = new journal_flusher_co[max_flusher_count];
     for (int i = 0; i < max_flusher_count; i++)
     {
@@ -486,28 +486,28 @@ resume_1:
             bs->ringloop->wakeup();
         }
         // Reads completed, submit writes and set bitmap bits
-        if (bs->clean_entry_bitmap_size)
+        if (bs->dsk.clean_entry_bitmap_size)
         {
             new_clean_bitmap = (bs->inmemory_meta
-                ? (uint8_t*)meta_new.buf + meta_new.pos*bs->clean_entry_size + sizeof(clean_disk_entry)
-                : (uint8_t*)bs->clean_bitmap + (clean_loc >> bs->block_order)*(2*bs->clean_entry_bitmap_size));
+                ? (uint8_t*)meta_new.buf + meta_new.pos*bs->dsk.clean_entry_size + sizeof(clean_disk_entry)
+                : (uint8_t*)bs->clean_bitmap + (clean_loc >> bs->dsk.block_order)*(2*bs->dsk.clean_entry_bitmap_size));
             if (clean_init_bitmap)
             {
-                memset(new_clean_bitmap, 0, bs->clean_entry_bitmap_size);
-                bitmap_set(new_clean_bitmap, clean_bitmap_offset, clean_bitmap_len, bs->bitmap_granularity);
+                memset(new_clean_bitmap, 0, bs->dsk.clean_entry_bitmap_size);
+                bitmap_set(new_clean_bitmap, clean_bitmap_offset, clean_bitmap_len, bs->dsk.bitmap_granularity);
             }
         }
         for (it = v.begin(); it != v.end(); it++)
         {
             if (new_clean_bitmap)
             {
-                bitmap_set(new_clean_bitmap, it->offset, it->len, bs->bitmap_granularity);
+                bitmap_set(new_clean_bitmap, it->offset, it->len, bs->dsk.bitmap_granularity);
             }
             await_sqe(4);
             data->iov = (struct iovec){ it->buf, (size_t)it->len };
             data->callback = simple_callback_w;
             my_uring_prep_writev(
-                sqe, bs->data_fd, &data->iov, 1, bs->data_offset + clean_loc + it->offset
+                sqe, bs->dsk.data_fd, &data->iov, 1, bs->dsk.data_offset + clean_loc + it->offset
             );
             wait_count++;
         }
@@ -536,35 +536,35 @@ resume_1:
                 return false;
             }
             // zero out old metadata entry
-            memset((uint8_t*)meta_old.buf + meta_old.pos*bs->clean_entry_size, 0, bs->clean_entry_size);
+            memset((uint8_t*)meta_old.buf + meta_old.pos*bs->dsk.clean_entry_size, 0, bs->dsk.clean_entry_size);
             await_sqe(15);
-            data->iov = (struct iovec){ meta_old.buf, bs->meta_block_size };
+            data->iov = (struct iovec){ meta_old.buf, bs->dsk.meta_block_size };
             data->callback = simple_callback_w;
             my_uring_prep_writev(
-                sqe, bs->meta_fd, &data->iov, 1, bs->meta_offset + meta_old.sector
+                sqe, bs->dsk.meta_fd, &data->iov, 1, bs->dsk.meta_offset + meta_old.sector
             );
             wait_count++;
         }
         if (has_delete)
         {
-            clean_disk_entry *new_entry = (clean_disk_entry*)((uint8_t*)meta_new.buf + meta_new.pos*bs->clean_entry_size);
+            clean_disk_entry *new_entry = (clean_disk_entry*)((uint8_t*)meta_new.buf + meta_new.pos*bs->dsk.clean_entry_size);
             if (new_entry->oid.inode != 0 && new_entry->oid != cur.oid)
             {
                 printf("Fatal error (metadata corruption or bug): tried to delete metadata entry %lu (%lx:%lx v%lu) while deleting %lx:%lx\n",
-                    clean_loc >> bs->block_order, new_entry->oid.inode, new_entry->oid.stripe,
+                    clean_loc >> bs->dsk.block_order, new_entry->oid.inode, new_entry->oid.stripe,
                     new_entry->version, cur.oid.inode, cur.oid.stripe);
                 exit(1);
             }
             // zero out new metadata entry
-            memset((uint8_t*)meta_new.buf + meta_new.pos*bs->clean_entry_size, 0, bs->clean_entry_size);
+            memset((uint8_t*)meta_new.buf + meta_new.pos*bs->dsk.clean_entry_size, 0, bs->dsk.clean_entry_size);
         }
         else
         {
-            clean_disk_entry *new_entry = (clean_disk_entry*)((uint8_t*)meta_new.buf + meta_new.pos*bs->clean_entry_size);
+            clean_disk_entry *new_entry = (clean_disk_entry*)((uint8_t*)meta_new.buf + meta_new.pos*bs->dsk.clean_entry_size);
             if (new_entry->oid.inode != 0 && new_entry->oid != cur.oid)
             {
                 printf("Fatal error (metadata corruption or bug): tried to overwrite non-zero metadata entry %lu (%lx:%lx v%lu) with %lx:%lx v%lu\n",
-                    clean_loc >> bs->block_order, new_entry->oid.inode, new_entry->oid.stripe, new_entry->version,
+                    clean_loc >> bs->dsk.block_order, new_entry->oid.inode, new_entry->oid.stripe, new_entry->version,
                     cur.oid.inode, cur.oid.stripe, cur.version);
                 exit(1);
             }
@@ -572,20 +572,20 @@ resume_1:
             new_entry->version = cur.version;
             if (!bs->inmemory_meta)
             {
-                memcpy(&new_entry->bitmap, new_clean_bitmap, bs->clean_entry_bitmap_size);
+                memcpy(&new_entry->bitmap, new_clean_bitmap, bs->dsk.clean_entry_bitmap_size);
             }
             // copy latest external bitmap/attributes
-            if (bs->clean_entry_bitmap_size)
+            if (bs->dsk.clean_entry_bitmap_size)
             {
-                void *bmp_ptr = bs->clean_entry_bitmap_size > sizeof(void*) ? dirty_end->second.bitmap : &dirty_end->second.bitmap;
-                memcpy((uint8_t*)(new_entry+1) + bs->clean_entry_bitmap_size, bmp_ptr, bs->clean_entry_bitmap_size);
+                void *bmp_ptr = bs->dsk.clean_entry_bitmap_size > sizeof(void*) ? dirty_end->second.bitmap : &dirty_end->second.bitmap;
+                memcpy((uint8_t*)(new_entry+1) + bs->dsk.clean_entry_bitmap_size, bmp_ptr, bs->dsk.clean_entry_bitmap_size);
             }
         }
         await_sqe(6);
-        data->iov = (struct iovec){ meta_new.buf, bs->meta_block_size };
+        data->iov = (struct iovec){ meta_new.buf, bs->dsk.meta_block_size };
         data->callback = simple_callback_w;
         my_uring_prep_writev(
-            sqe, bs->meta_fd, &data->iov, 1, bs->meta_offset + meta_new.sector
+            sqe, bs->dsk.meta_fd, &data->iov, 1, bs->dsk.meta_offset + meta_new.sector
         );
         wait_count++;
     resume_7:
@@ -669,9 +669,9 @@ resume_1:
                     .version = JOURNAL_VERSION,
                 };
                 ((journal_entry_start*)flusher->journal_superblock)->crc32 = je_crc32((journal_entry*)flusher->journal_superblock);
-                data->iov = (struct iovec){ flusher->journal_superblock, bs->journal_block_size };
+                data->iov = (struct iovec){ flusher->journal_superblock, bs->dsk.journal_block_size };
                 data->callback = simple_callback_w;
-                my_uring_prep_writev(sqe, bs->journal.fd, &data->iov, 1, bs->journal.offset);
+                my_uring_prep_writev(sqe, bs->dsk.journal_fd, &data->iov, 1, bs->journal.offset);
                 wait_count++;
             resume_13:
                 if (wait_count > 0)
@@ -682,7 +682,7 @@ resume_1:
                 if (!bs->disable_journal_fsync)
                 {
                     await_sqe(20);
-                    my_uring_prep_fsync(sqe, bs->journal.fd, IORING_FSYNC_DATASYNC);
+                    my_uring_prep_fsync(sqe, bs->dsk.journal_fd, IORING_FSYNC_DATASYNC);
                     data->iov = { 0 };
                     data->callback = simple_callback_w;
                 resume_21:
@@ -774,7 +774,7 @@ bool journal_flusher_co::scan_dirty(int wait_base)
                             data->iov = (struct iovec){ it->buf, (size_t)submit_len };
                             data->callback = simple_callback_r;
                             my_uring_prep_readv(
-                                sqe, bs->journal.fd, &data->iov, 1, bs->journal.offset + submit_offset
+                                sqe, bs->dsk.journal_fd, &data->iov, 1, bs->journal.offset + submit_offset
                             );
                             wait_count++;
                         }
@@ -825,8 +825,8 @@ bool journal_flusher_co::modify_meta_read(uint64_t meta_loc, flusher_meta_write_
     // And yet another option is to use LSM trees for metadata, but it sophisticates everything a lot,
     // so I'll avoid it as long as I can.
     wr.submitted = false;
-    wr.sector = ((meta_loc >> bs->block_order) / (bs->meta_block_size / bs->clean_entry_size)) * bs->meta_block_size;
-    wr.pos = ((meta_loc >> bs->block_order) % (bs->meta_block_size / bs->clean_entry_size));
+    wr.sector = ((meta_loc >> bs->dsk.block_order) / (bs->dsk.meta_block_size / bs->dsk.clean_entry_size)) * bs->dsk.meta_block_size;
+    wr.pos = ((meta_loc >> bs->dsk.block_order) % (bs->dsk.meta_block_size / bs->dsk.clean_entry_size));
     if (bs->inmemory_meta)
     {
         wr.buf = (uint8_t*)bs->metadata_buffer + wr.sector;
@@ -836,20 +836,20 @@ bool journal_flusher_co::modify_meta_read(uint64_t meta_loc, flusher_meta_write_
     if (wr.it == flusher->meta_sectors.end())
     {
         // Not in memory yet, read it
-        wr.buf = memalign_or_die(MEM_ALIGNMENT, bs->meta_block_size);
+        wr.buf = memalign_or_die(MEM_ALIGNMENT, bs->dsk.meta_block_size);
         wr.it = flusher->meta_sectors.emplace(wr.sector, (meta_sector_t){
             .offset = wr.sector,
-            .len = bs->meta_block_size,
+            .len = bs->dsk.meta_block_size,
             .state = 0, // 0 = not read yet
             .buf = wr.buf,
             .usage_count = 1,
         }).first;
         await_sqe(0);
-        data->iov = (struct iovec){ wr.it->second.buf, bs->meta_block_size };
+        data->iov = (struct iovec){ wr.it->second.buf, bs->dsk.meta_block_size };
         data->callback = simple_callback_r;
         wr.submitted = true;
         my_uring_prep_readv(
-            sqe, bs->meta_fd, &data->iov, 1, bs->meta_offset + wr.sector
+            sqe, bs->dsk.meta_fd, &data->iov, 1, bs->dsk.meta_offset + wr.sector
         );
         wait_count++;
     }
@@ -867,11 +867,11 @@ void journal_flusher_co::update_clean_db()
     {
 #ifdef BLOCKSTORE_DEBUG
         printf("Free block %lu from %lx:%lx v%lu (new location is %lu)\n",
-            old_clean_loc >> bs->block_order,
+            old_clean_loc >> bs->dsk.block_order,
             cur.oid.inode, cur.oid.stripe, cur.version,
-            clean_loc >> bs->block_order);
+            clean_loc >> bs->dsk.block_order);
 #endif
-        bs->data_alloc->set(old_clean_loc >> bs->block_order, false);
+        bs->data_alloc->set(old_clean_loc >> bs->dsk.block_order, false);
     }
     auto & clean_db = bs->clean_db_shard(cur.oid);
     if (has_delete)
@@ -880,10 +880,10 @@ void journal_flusher_co::update_clean_db()
         clean_db.erase(clean_it);
 #ifdef BLOCKSTORE_DEBUG
         printf("Free block %lu from %lx:%lx v%lu (delete)\n",
-            clean_loc >> bs->block_order,
+            clean_loc >> bs->dsk.block_order,
             cur.oid.inode, cur.oid.stripe, cur.version);
 #endif
-        bs->data_alloc->set(clean_loc >> bs->block_order, false);
+        bs->data_alloc->set(clean_loc >> bs->dsk.block_order, false);
         clean_loc = UINT64_MAX;
     }
     else
@@ -932,7 +932,7 @@ bool journal_flusher_co::fsync_batch(bool fsync_meta, int wait_base)
                 await_sqe(0);
                 data->iov = { 0 };
                 data->callback = simple_callback_w;
-                my_uring_prep_fsync(sqe, fsync_meta ? bs->meta_fd : bs->data_fd, IORING_FSYNC_DATASYNC);
+                my_uring_prep_fsync(sqe, fsync_meta ? bs->dsk.meta_fd : bs->dsk.data_fd, IORING_FSYNC_DATASYNC);
                 cur_sync->state = 1;
                 wait_count++;
             resume_2:
diff --git a/src/blockstore_impl.cpp b/src/blockstore_impl.cpp
index f10a5e86..dfb0835b 100644
--- a/src/blockstore_impl.cpp
+++ b/src/blockstore_impl.cpp
@@ -11,25 +11,19 @@ blockstore_impl_t::blockstore_impl_t(blockstore_config_t & config, ring_loop_t *
     ring_consumer.loop = [this]() { loop(); };
     ringloop->register_consumer(&ring_consumer);
     initialized = 0;
-    data_fd = meta_fd = journal.fd = -1;
     parse_config(config);
-    zero_object = (uint8_t*)memalign_or_die(MEM_ALIGNMENT, data_block_size);
+    zero_object = (uint8_t*)memalign_or_die(MEM_ALIGNMENT, dsk.data_block_size);
     try
     {
-        open_data();
-        open_meta();
-        open_journal();
+        dsk.open_data();
+        dsk.open_meta();
+        dsk.open_journal();
         calc_lengths();
-        data_alloc = new allocator(block_count);
+        data_alloc = new allocator(dsk.block_count);
     }
     catch (std::exception & e)
     {
-        if (data_fd >= 0)
-            close(data_fd);
-        if (meta_fd >= 0 && meta_fd != data_fd)
-            close(meta_fd);
-        if (journal.fd >= 0 && journal.fd != meta_fd)
-            close(journal.fd);
+        dsk.close_all();
         throw;
     }
     flusher = new journal_flusher_t(this);
@@ -41,12 +35,7 @@ blockstore_impl_t::~blockstore_impl_t()
     delete flusher;
     free(zero_object);
     ringloop->unregister_consumer(&ring_consumer);
-    if (data_fd >= 0)
-        close(data_fd);
-    if (meta_fd >= 0 && meta_fd != data_fd)
-        close(meta_fd);
-    if (journal.fd >= 0 && journal.fd != meta_fd)
-        close(journal.fd);
+    dsk.close_all();
     if (metadata_buffer)
         free(metadata_buffer);
     if (clean_bitmap)
@@ -343,9 +332,9 @@ void blockstore_impl_t::enqueue_op(blockstore_op_t *op)
 {
     if (op->opcode < BS_OP_MIN || op->opcode > BS_OP_MAX ||
         ((op->opcode == BS_OP_READ || op->opcode == BS_OP_WRITE || op->opcode == BS_OP_WRITE_STABLE) && (
-            op->offset >= data_block_size ||
-            op->len > data_block_size-op->offset ||
-            (op->len % disk_alignment)
+            op->offset >= dsk.data_block_size ||
+            op->len > dsk.data_block_size-op->offset ||
+            (op->len % dsk.disk_alignment)
         )) ||
         readonly && op->opcode != BS_OP_READ && op->opcode != BS_OP_LIST)
     {
diff --git a/src/blockstore_impl.h b/src/blockstore_impl.h
index 51f61be4..fab3665a 100644
--- a/src/blockstore_impl.h
+++ b/src/blockstore_impl.h
@@ -4,6 +4,7 @@
 #pragma once
 
 #include "blockstore.h"
+#include "blockstore_disk.h"
 
 #include <sys/types.h>
 #include <sys/ioctl.h>
@@ -218,23 +219,10 @@ struct pool_shard_settings_t
 
 class blockstore_impl_t
 {
+    blockstore_disk_t dsk;
+
     /******* OPTIONS *******/
-    std::string data_device, meta_device, journal_device;
-    uint32_t data_block_size;
-    uint64_t meta_offset;
-    uint64_t data_offset;
-    uint64_t cfg_journal_size, cfg_data_size;
-    // Required write alignment and journal/metadata/data areas' location alignment
-    uint32_t disk_alignment = 4096;
-    // Journal block size - minimum_io_size of the journal device is the best choice
-    uint64_t journal_block_size = 4096;
-    // Metadata block size - minimum_io_size of the metadata device is the best choice
-    uint64_t meta_block_size = 4096;
-    // Sparse write tracking granularity. 4 KB is a good choice. Must be a multiple of disk_alignment
-    uint64_t bitmap_granularity = 4096;
     bool readonly = false;
-    // By default, Blockstore locks all opened devices exclusively. This option can be used to disable locking
-    bool disable_flock = false;
     // It is safe to disable fsync() if drive write cache is writethrough
     bool disable_data_fsync = false, disable_meta_fsync = false, disable_journal_fsync = false;
     // Enable if you want every operation to be executed with an "implicit fsync"
@@ -269,16 +257,6 @@ class blockstore_impl_t
     allocator *data_alloc = NULL;
     uint8_t *zero_object;
 
-    uint32_t block_order;
-    uint64_t block_count;
-    uint32_t clean_entry_bitmap_size = 0, clean_entry_size = 0;
-
-    int meta_fd;
-    int data_fd;
-    uint64_t meta_device_size, meta_len;
-    uint64_t data_device_size, data_len;
-    uint64_t data_device_sect, meta_device_sect, journal_device_sect;
-
     void *metadata_buffer = NULL;
 
     struct journal_t journal;
@@ -395,9 +373,9 @@ public:
     // Print diagnostics to stdout
     void dump_diagnostics();
 
-    inline uint32_t get_block_size() { return data_block_size; }
-    inline uint64_t get_block_count() { return block_count; }
+    inline uint32_t get_block_size() { return dsk.data_block_size; }
+    inline uint64_t get_block_count() { return dsk.block_count; }
     inline uint64_t get_free_block_count() { return data_alloc->get_free_count(); }
-    inline uint32_t get_bitmap_granularity() { return disk_alignment; }
-    inline uint64_t get_journal_size() { return journal.len; }
+    inline uint32_t get_bitmap_granularity() { return dsk.disk_alignment; }
+    inline uint64_t get_journal_size() { return dsk.journal_len; }
 };
diff --git a/src/blockstore_init.cpp b/src/blockstore_init.cpp
index f9c88681..2dad747a 100644
--- a/src/blockstore_init.cpp
+++ b/src/blockstore_init.cpp
@@ -57,9 +57,9 @@ int blockstore_init_meta::loop()
         throw std::runtime_error("Failed to allocate metadata read buffer");
     // Read superblock
     GET_SQE();
-    data->iov = { metadata_buffer, bs->meta_block_size };
+    data->iov = { metadata_buffer, bs->dsk.meta_block_size };
     data->callback = [this](ring_data_t *data) { handle_event(data); };
-    my_uring_prep_readv(sqe, bs->meta_fd, &data->iov, 1, bs->meta_offset);
+    my_uring_prep_readv(sqe, bs->dsk.meta_fd, &data->iov, 1, bs->dsk.meta_offset);
     bs->ringloop->submit();
     submitted = 1;
 resume_1:
@@ -68,16 +68,16 @@ resume_1:
         wait_state = 1;
         return 1;
     }
-    if (iszero((uint64_t*)metadata_buffer, bs->meta_block_size / sizeof(uint64_t)))
+    if (iszero((uint64_t*)metadata_buffer, bs->dsk.meta_block_size / sizeof(uint64_t)))
     {
         {
             blockstore_meta_header_v1_t *hdr = (blockstore_meta_header_v1_t *)metadata_buffer;
             hdr->zero = 0;
             hdr->magic = BLOCKSTORE_META_MAGIC_V1;
             hdr->version = BLOCKSTORE_META_VERSION_V1;
-            hdr->meta_block_size = bs->meta_block_size;
-            hdr->data_block_size = bs->data_block_size;
-            hdr->bitmap_granularity = bs->bitmap_granularity;
+            hdr->meta_block_size = bs->dsk.meta_block_size;
+            hdr->data_block_size = bs->dsk.data_block_size;
+            hdr->bitmap_granularity = bs->dsk.bitmap_granularity;
         }
         if (bs->readonly)
         {
@@ -87,9 +87,9 @@ resume_1:
         {
             printf("Initializing metadata area\n");
             GET_SQE();
-            data->iov = (struct iovec){ metadata_buffer, bs->meta_block_size };
+            data->iov = (struct iovec){ metadata_buffer, bs->dsk.meta_block_size };
             data->callback = [this](ring_data_t *data) { handle_event(data); };
-            my_uring_prep_writev(sqe, bs->meta_fd, &data->iov, 1, bs->meta_offset);
+            my_uring_prep_writev(sqe, bs->dsk.meta_fd, &data->iov, 1, bs->dsk.meta_offset);
             bs->ringloop->submit();
             submitted = 1;
         resume_3:
@@ -115,23 +115,23 @@ resume_1:
             );
             exit(1);
         }
-        if (hdr->meta_block_size != bs->meta_block_size ||
-            hdr->data_block_size != bs->data_block_size ||
-            hdr->bitmap_granularity != bs->bitmap_granularity)
+        if (hdr->meta_block_size != bs->dsk.meta_block_size ||
+            hdr->data_block_size != bs->dsk.data_block_size ||
+            hdr->bitmap_granularity != bs->dsk.bitmap_granularity)
         {
             printf(
                 "Configuration stored in metadata superblock"
                 " (meta_block_size=%u, data_block_size=%u, bitmap_granularity=%u)"
                 " differs from OSD configuration (%lu/%u/%lu).\n",
                 hdr->meta_block_size, hdr->data_block_size, hdr->bitmap_granularity,
-                bs->meta_block_size, bs->data_block_size, bs->bitmap_granularity
+                bs->dsk.meta_block_size, bs->dsk.data_block_size, bs->dsk.bitmap_granularity
             );
             exit(1);
         }
     }
     // Skip superblock
-    bs->meta_offset += bs->meta_block_size;
-    bs->meta_len -= bs->meta_block_size;
+    bs->dsk.meta_offset += bs->dsk.meta_block_size;
+    bs->dsk.meta_len -= bs->dsk.meta_block_size;
     prev_done = 0;
     done_len = 0;
     done_pos = 0;
@@ -145,23 +145,23 @@ resume_1:
             wait_state = 2;
             return 1;
         }
-        if (metadata_read < bs->meta_len)
+        if (metadata_read < bs->dsk.meta_len)
         {
             GET_SQE();
             data->iov = {
                 (uint8_t*)metadata_buffer + (bs->inmemory_meta
                     ? metadata_read
                     : (prev == 1 ? bs->metadata_buf_size : 0)),
-                bs->meta_len - metadata_read > bs->metadata_buf_size ? bs->metadata_buf_size : bs->meta_len - metadata_read,
+                bs->dsk.meta_len - metadata_read > bs->metadata_buf_size ? bs->metadata_buf_size : bs->dsk.meta_len - metadata_read,
             };
             data->callback = [this](ring_data_t *data) { handle_event(data); };
             if (!zero_on_init)
-                my_uring_prep_readv(sqe, bs->meta_fd, &data->iov, 1, bs->meta_offset + metadata_read);
+                my_uring_prep_readv(sqe, bs->dsk.meta_fd, &data->iov, 1, bs->dsk.meta_offset + metadata_read);
             else
             {
                 // Fill metadata with zeroes
                 memset(data->iov.iov_base, 0, data->iov.iov_len);
-                my_uring_prep_writev(sqe, bs->meta_fd, &data->iov, 1, bs->meta_offset + metadata_read);
+                my_uring_prep_writev(sqe, bs->dsk.meta_fd, &data->iov, 1, bs->dsk.meta_offset + metadata_read);
             }
             bs->ringloop->submit();
             submitted = (prev == 1 ? 2 : 1);
@@ -172,11 +172,11 @@ resume_1:
             void *done_buf = bs->inmemory_meta
                 ? ((uint8_t*)metadata_buffer + done_pos)
                 : ((uint8_t*)metadata_buffer + (prev_done == 2 ? bs->metadata_buf_size : 0));
-            unsigned count = bs->meta_block_size / bs->clean_entry_size;
-            for (int sector = 0; sector < done_len; sector += bs->meta_block_size)
+            unsigned count = bs->dsk.meta_block_size / bs->dsk.clean_entry_size;
+            for (int sector = 0; sector < done_len; sector += bs->dsk.meta_block_size)
             {
                 // handle <count> entries
-                handle_entries((uint8_t*)done_buf + sector, count, bs->block_order);
+                handle_entries((uint8_t*)done_buf + sector, count, bs->dsk.block_order);
                 done_cnt += count;
             }
             prev_done = 0;
@@ -188,7 +188,7 @@ resume_1:
         }
     }
     // metadata read finished
-    printf("Metadata entries loaded: %lu, free blocks: %lu / %lu\n", entries_loaded, bs->data_alloc->get_free_count(), bs->block_count);
+    printf("Metadata entries loaded: %lu, free blocks: %lu / %lu\n", entries_loaded, bs->data_alloc->get_free_count(), bs->dsk.block_count);
     if (!bs->inmemory_meta)
     {
         free(metadata_buffer);
@@ -197,7 +197,7 @@ resume_1:
     if (zero_on_init && !bs->disable_meta_fsync)
     {
         GET_SQE();
-        my_uring_prep_fsync(sqe, bs->meta_fd, IORING_FSYNC_DATASYNC);
+        my_uring_prep_fsync(sqe, bs->dsk.meta_fd, IORING_FSYNC_DATASYNC);
         data->iov = { 0 };
         data->callback = [this](ring_data_t *data) { handle_event(data); };
         submitted = 1;
@@ -216,10 +216,10 @@ void blockstore_init_meta::handle_entries(void* entries, unsigned count, int blo
 {
     for (unsigned i = 0; i < count; i++)
     {
-        clean_disk_entry *entry = (clean_disk_entry*)((uint8_t*)entries + i*bs->clean_entry_size);
-        if (!bs->inmemory_meta && bs->clean_entry_bitmap_size)
+        clean_disk_entry *entry = (clean_disk_entry*)((uint8_t*)entries + i*bs->dsk.clean_entry_size);
+        if (!bs->inmemory_meta && bs->dsk.clean_entry_bitmap_size)
         {
-            memcpy(bs->clean_bitmap + (done_cnt+i)*2*bs->clean_entry_bitmap_size, &entry->bitmap, 2*bs->clean_entry_bitmap_size);
+            memcpy(bs->clean_bitmap + (done_cnt+i)*2*bs->dsk.clean_entry_bitmap_size, &entry->bitmap, 2*bs->dsk.clean_entry_bitmap_size);
         }
         if (entry->oid.inode > 0)
         {
@@ -240,7 +240,7 @@ void blockstore_init_meta::handle_entries(void* entries, unsigned count, int blo
                 }
                 else
                 {
-                    bs->inode_space_stats[entry->oid.inode] += bs->data_block_size;
+                    bs->inode_space_stats[entry->oid.inode] += bs->dsk.data_block_size;
                 }
                 entries_loaded++;
 #ifdef BLOCKSTORE_DEBUG
@@ -328,7 +328,7 @@ int blockstore_init_journal::loop()
     data = ((ring_data_t*)sqe->user_data);
     data->iov = { submitted_buf, bs->journal.block_size };
     data->callback = simple_callback;
-    my_uring_prep_readv(sqe, bs->journal.fd, &data->iov, 1, bs->journal.offset);
+    my_uring_prep_readv(sqe, bs->dsk.journal_fd, &data->iov, 1, bs->journal.offset);
     bs->ringloop->submit();
     wait_count = 1;
 resume_1:
@@ -367,7 +367,7 @@ resume_1:
             GET_SQE();
             data->iov = (struct iovec){ submitted_buf, 2*bs->journal.block_size };
             data->callback = simple_callback;
-            my_uring_prep_writev(sqe, bs->journal.fd, &data->iov, 1, bs->journal.offset);
+            my_uring_prep_writev(sqe, bs->dsk.journal_fd, &data->iov, 1, bs->journal.offset);
             wait_count++;
             bs->ringloop->submit();
         resume_6:
@@ -379,7 +379,7 @@ resume_1:
             if (!bs->disable_journal_fsync)
             {
                 GET_SQE();
-                my_uring_prep_fsync(sqe, bs->journal.fd, IORING_FSYNC_DATASYNC);
+                my_uring_prep_fsync(sqe, bs->dsk.journal_fd, IORING_FSYNC_DATASYNC);
                 data->iov = { 0 };
                 data->callback = simple_callback;
                 wait_count++;
@@ -448,7 +448,7 @@ resume_1:
                     end - journal_pos < JOURNAL_BUFFER_SIZE ? end - journal_pos : JOURNAL_BUFFER_SIZE,
                 };
                 data->callback = [this](ring_data_t *data1) { handle_event(data1); };
-                my_uring_prep_readv(sqe, bs->journal.fd, &data->iov, 1, bs->journal.offset + journal_pos);
+                my_uring_prep_readv(sqe, bs->dsk.journal_fd, &data->iov, 1, bs->journal.offset + journal_pos);
                 bs->ringloop->submit();
             }
             while (done.size() > 0)
@@ -463,7 +463,7 @@ resume_1:
                         GET_SQE();
                         data->iov = { init_write_buf, bs->journal.block_size };
                         data->callback = simple_callback;
-                        my_uring_prep_writev(sqe, bs->journal.fd, &data->iov, 1, bs->journal.offset + init_write_sector);
+                        my_uring_prep_writev(sqe, bs->dsk.journal_fd, &data->iov, 1, bs->journal.offset + init_write_sector);
                         wait_count++;
                         bs->ringloop->submit();
                     resume_7:
@@ -477,7 +477,7 @@ resume_1:
                             GET_SQE();
                             data->iov = { 0 };
                             data->callback = simple_callback;
-                            my_uring_prep_fsync(sqe, bs->journal.fd, IORING_FSYNC_DATASYNC);
+                            my_uring_prep_fsync(sqe, bs->dsk.journal_fd, IORING_FSYNC_DATASYNC);
                             wait_count++;
                             bs->ringloop->submit();
                         }
@@ -544,7 +544,7 @@ resume_1:
             ? bs->journal.len-bs->journal.block_size - (bs->journal.next_free-bs->journal.used_start)
             : bs->journal.used_start - bs->journal.next_free),
         bs->journal.used_start, bs->journal.next_free,
-        bs->data_alloc->get_free_count(), bs->block_count
+        bs->data_alloc->get_free_count(), bs->dsk.block_count
     );
     bs->journal.crc32_last = crc32_last;
     return 0;
@@ -669,9 +669,9 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
                     };
                     void *bmp = NULL;
                     void *bmp_from = (uint8_t*)je + sizeof(journal_entry_small_write);
-                    if (bs->clean_entry_bitmap_size <= sizeof(void*))
+                    if (bs->dsk.clean_entry_bitmap_size <= sizeof(void*))
                     {
-                        memcpy(&bmp, bmp_from, bs->clean_entry_bitmap_size);
+                        memcpy(&bmp, bmp_from, bs->dsk.clean_entry_bitmap_size);
                     }
                     else
                     {
@@ -679,8 +679,8 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
                         // allocations for entry bitmaps. This can only be fixed by using
                         // a patched map with dynamic entry size, but not the btree_map,
                         // because it doesn't keep iterators valid all the time.
-                        bmp = malloc_or_die(bs->clean_entry_bitmap_size);
-                        memcpy(bmp, bmp_from, bs->clean_entry_bitmap_size);
+                        bmp = malloc_or_die(bs->dsk.clean_entry_bitmap_size);
+                        memcpy(bmp, bmp_from, bs->dsk.clean_entry_bitmap_size);
                     }
                     bs->dirty_db.emplace(ov, (dirty_entry){
                         .state = (BS_ST_SMALL_WRITE | BS_ST_SYNCED),
@@ -712,7 +712,7 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
                 printf(
                     "je_big_write%s oid=%lx:%lx ver=%lu loc=%lu\n",
                     je->type == JE_BIG_WRITE_INSTANT ? "_instant" : "",
-                    je->big_write.oid.inode, je->big_write.oid.stripe, je->big_write.version, je->big_write.location >> bs->block_order
+                    je->big_write.oid.inode, je->big_write.oid.stripe, je->big_write.version, je->big_write.location >> bs->dsk.block_order
                 );
 #endif
                 auto dirty_it = bs->dirty_db.upper_bound((obj_ver_id){
@@ -750,9 +750,9 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
                     };
                     void *bmp = NULL;
                     void *bmp_from = (uint8_t*)je + sizeof(journal_entry_big_write);
-                    if (bs->clean_entry_bitmap_size <= sizeof(void*))
+                    if (bs->dsk.clean_entry_bitmap_size <= sizeof(void*))
                     {
-                        memcpy(&bmp, bmp_from, bs->clean_entry_bitmap_size);
+                        memcpy(&bmp, bmp_from, bs->dsk.clean_entry_bitmap_size);
                     }
                     else
                     {
@@ -760,8 +760,8 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
                         // allocations for entry bitmaps. This can only be fixed by using
                         // a patched map with dynamic entry size, but not the btree_map,
                         // because it doesn't keep iterators valid all the time.
-                        bmp = malloc_or_die(bs->clean_entry_bitmap_size);
-                        memcpy(bmp, bmp_from, bs->clean_entry_bitmap_size);
+                        bmp = malloc_or_die(bs->dsk.clean_entry_bitmap_size);
+                        memcpy(bmp, bmp_from, bs->dsk.clean_entry_bitmap_size);
                     }
                     auto dirty_it = bs->dirty_db.emplace(ov, (dirty_entry){
                         .state = (BS_ST_BIG_WRITE | BS_ST_SYNCED),
@@ -772,7 +772,7 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
                         .journal_sector = proc_pos,
                         .bitmap = bmp,
                     }).first;
-                    if (bs->data_alloc->get(je->big_write.location >> bs->block_order))
+                    if (bs->data_alloc->get(je->big_write.location >> bs->dsk.block_order))
                     {
                         // This is probably a big_write that's already flushed and freed, but it may
                         // also indicate a bug. So we remember such entries and recheck them afterwards.
@@ -785,11 +785,11 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
 #ifdef BLOCKSTORE_DEBUG
                         printf(
                             "Allocate block (journal) %lu: %lx:%lx v%lu\n",
-                            je->big_write.location >> bs->block_order,
+                            je->big_write.location >> bs->dsk.block_order,
                             ov.oid.inode, ov.oid.stripe, ov.version
                         );
 #endif
-                        bs->data_alloc->set(je->big_write.location >> bs->block_order, true);
+                        bs->data_alloc->set(je->big_write.location >> bs->dsk.block_order, true);
                     }
                     bs->journal.used_sectors[proc_pos]++;
 #ifdef BLOCKSTORE_DEBUG
@@ -913,8 +913,8 @@ void blockstore_init_journal::erase_dirty_object(blockstore_dirty_db_t::iterator
     if (exists && clean_loc == UINT64_MAX)
     {
         auto & sp = bs->inode_space_stats[oid.inode];
-        if (sp > bs->data_block_size)
-            sp -= bs->data_block_size;
+        if (sp > bs->dsk.data_block_size)
+            sp -= bs->dsk.data_block_size;
         else
             bs->inode_space_stats.erase(oid.inode);
     }
diff --git a/src/blockstore_journal.cpp b/src/blockstore_journal.cpp
index 59977201..3c8699d9 100644
--- a/src/blockstore_journal.cpp
+++ b/src/blockstore_journal.cpp
@@ -175,7 +175,7 @@ void blockstore_impl_t::prepare_journal_sector_write(int cur_sector, blockstore_
         };
         data->callback = [this, flush_id = journal.submit_id](ring_data_t *data) { handle_journal_write(data, flush_id); };
         my_uring_prep_writev(
-            sqe, journal.fd, &data->iov, 1, journal.offset + journal.sector_info[cur_sector].offset
+            sqe, dsk.journal_fd, &data->iov, 1, journal.offset + journal.sector_info[cur_sector].offset
         );
     }
     journal.sector_info[cur_sector].dirty = false;
diff --git a/src/blockstore_journal.h b/src/blockstore_journal.h
index 0f401ff1..1023fd8b 100644
--- a/src/blockstore_journal.h
+++ b/src/blockstore_journal.h
@@ -164,7 +164,6 @@ inline bool operator < (const pending_journaling_t & a, const pending_journaling
 struct journal_t
 {
     int fd;
-    uint64_t device_size;
     bool inmemory = false;
     bool flush_journal = false;
     void *buffer = NULL;
diff --git a/src/blockstore_open.cpp b/src/blockstore_open.cpp
index 05f0902d..adcfea7c 100644
--- a/src/blockstore_open.cpp
+++ b/src/blockstore_open.cpp
@@ -4,23 +4,10 @@
 #include <sys/file.h>
 #include "blockstore_impl.h"
 
-static uint32_t is_power_of_two(uint64_t value)
-{
-    uint32_t l = 0;
-    while (value > 1)
-    {
-        if (value & 1)
-        {
-            return 64;
-        }
-        value = value >> 1;
-        l++;
-    }
-    return l;
-}
-
 void blockstore_impl_t::parse_config(blockstore_config_t & config)
 {
+    // Common disk options
+    dsk.parse_config(config);
     // Parse
     if (config["readonly"] == "true" || config["readonly"] == "1" || config["readonly"] == "yes")
     {
@@ -38,10 +25,6 @@ void blockstore_impl_t::parse_config(blockstore_config_t & config)
     {
         disable_journal_fsync = true;
     }
-    if (config["disable_device_lock"] == "true" || config["disable_device_lock"] == "1" || config["disable_device_lock"] == "yes")
-    {
-        disable_flock = true;
-    }
     if (config["flush_journal"] == "true" || config["flush_journal"] == "1" || config["flush_journal"] == "yes")
     {
         // Only flush journal and exit
@@ -56,24 +39,11 @@ void blockstore_impl_t::parse_config(blockstore_config_t & config)
         immediate_commit = IMMEDIATE_SMALL;
     }
     metadata_buf_size = strtoull(config["meta_buf_size"].c_str(), NULL, 10);
-    cfg_journal_size = strtoull(config["journal_size"].c_str(), NULL, 10);
-    data_device = config["data_device"];
-    data_offset = strtoull(config["data_offset"].c_str(), NULL, 10);
-    cfg_data_size = strtoull(config["data_size"].c_str(), NULL, 10);
-    meta_device = config["meta_device"];
-    meta_offset = strtoull(config["meta_offset"].c_str(), NULL, 10);
-    data_block_size = strtoull(config["block_size"].c_str(), NULL, 10);
     inmemory_meta = config["inmemory_metadata"] != "false";
-    journal_device = config["journal_device"];
-    journal.offset = strtoull(config["journal_offset"].c_str(), NULL, 10);
     journal.sector_count = strtoull(config["journal_sector_buffer_count"].c_str(), NULL, 10);
     journal.no_same_sector_overwrites = config["journal_no_same_sector_overwrites"] == "true" ||
         config["journal_no_same_sector_overwrites"] == "1" || config["journal_no_same_sector_overwrites"] == "yes";
     journal.inmemory = config["inmemory_journal"] != "false";
-    disk_alignment = strtoull(config["disk_alignment"].c_str(), NULL, 10);
-    journal_block_size = strtoull(config["journal_block_size"].c_str(), NULL, 10);
-    meta_block_size = strtoull(config["meta_block_size"].c_str(), NULL, 10);
-    bitmap_granularity = strtoull(config["bitmap_granularity"].c_str(), NULL, 10);
     max_flusher_count = strtoull(config["max_flusher_count"].c_str(), NULL, 10);
     if (!max_flusher_count)
         max_flusher_count = strtoull(config["flusher_count"].c_str(), NULL, 10);
@@ -85,14 +55,6 @@ void blockstore_impl_t::parse_config(blockstore_config_t & config)
     throttle_target_parallelism = strtoull(config["throttle_target_parallelism"].c_str(), NULL, 10);
     throttle_threshold_us = strtoull(config["throttle_threshold_us"].c_str(), NULL, 10);
     // Validate
-    if (!data_block_size)
-    {
-        data_block_size = (1 << DEFAULT_DATA_BLOCK_ORDER);
-    }
-    if ((block_order = is_power_of_two(data_block_size)) >= 64 || data_block_size < MIN_DATA_BLOCK_SIZE || data_block_size >= MAX_DATA_BLOCK_SIZE)
-    {
-        throw std::runtime_error("Bad block size");
-    }
     if (!max_flusher_count)
     {
         max_flusher_count = 256;
@@ -105,62 +67,6 @@ void blockstore_impl_t::parse_config(blockstore_config_t & config)
     {
         max_write_iodepth = 128;
     }
-    if (!disk_alignment)
-    {
-        disk_alignment = 4096;
-    }
-    else if (disk_alignment % DIRECT_IO_ALIGNMENT)
-    {
-        throw std::runtime_error("disk_alignment must be a multiple of "+std::to_string(DIRECT_IO_ALIGNMENT));
-    }
-    if (!journal_block_size)
-    {
-        journal_block_size = 4096;
-    }
-    else if (journal_block_size % DIRECT_IO_ALIGNMENT)
-    {
-        throw std::runtime_error("journal_block_size must be a multiple of "+std::to_string(DIRECT_IO_ALIGNMENT));
-    }
-    if (!meta_block_size)
-    {
-        meta_block_size = 4096;
-    }
-    else if (meta_block_size % DIRECT_IO_ALIGNMENT)
-    {
-        throw std::runtime_error("meta_block_size must be a multiple of "+std::to_string(DIRECT_IO_ALIGNMENT));
-    }
-    if (data_offset % disk_alignment)
-    {
-        throw std::runtime_error("data_offset must be a multiple of disk_alignment = "+std::to_string(disk_alignment));
-    }
-    if (!bitmap_granularity)
-    {
-        bitmap_granularity = DEFAULT_BITMAP_GRANULARITY;
-    }
-    else if (bitmap_granularity % disk_alignment)
-    {
-        throw std::runtime_error("Sparse write tracking granularity must be a multiple of disk_alignment = "+std::to_string(disk_alignment));
-    }
-    if (data_block_size % bitmap_granularity)
-    {
-        throw std::runtime_error("Block size must be a multiple of sparse write tracking granularity");
-    }
-    if (journal_device == meta_device || meta_device == "" && journal_device == data_device)
-    {
-        journal_device = "";
-    }
-    if (meta_device == data_device)
-    {
-        meta_device = "";
-    }
-    if (meta_offset % meta_block_size)
-    {
-        throw std::runtime_error("meta_offset must be a multiple of meta_block_size = "+std::to_string(meta_block_size));
-    }
-    if (journal.offset % journal_block_size)
-    {
-        throw std::runtime_error("journal_offset must be a multiple of journal_block_size = "+std::to_string(journal_block_size));
-    }
     if (journal.sector_count < 2)
     {
         journal.sector_count = 32;
@@ -169,11 +75,11 @@ void blockstore_impl_t::parse_config(blockstore_config_t & config)
     {
         metadata_buf_size = 4*1024*1024;
     }
-    if (meta_device == "")
+    if (dsk.meta_device == "")
     {
         disable_meta_fsync = disable_data_fsync;
     }
-    if (journal_device == "")
+    if (dsk.journal_device == "")
     {
         disable_journal_fsync = disable_meta_fsync;
     }
@@ -202,238 +108,46 @@ void blockstore_impl_t::parse_config(blockstore_config_t & config)
         throttle_threshold_us = 50;
     }
     // init some fields
-    clean_entry_bitmap_size = data_block_size / bitmap_granularity / 8;
-    clean_entry_size = sizeof(clean_disk_entry) + 2*clean_entry_bitmap_size;
-    journal.block_size = journal_block_size;
-    journal.next_free = journal_block_size;
-    journal.used_start = journal_block_size;
+    journal.block_size = dsk.journal_block_size;
+    journal.next_free = dsk.journal_block_size;
+    journal.used_start = dsk.journal_block_size;
     // no free space because sector is initially unmapped
-    journal.in_sector_pos = journal_block_size;
+    journal.in_sector_pos = dsk.journal_block_size;
 }
 
 void blockstore_impl_t::calc_lengths()
 {
-    // data
-    data_len = data_device_size - data_offset;
-    if (data_fd == meta_fd && data_offset < meta_offset)
-    {
-        data_len = meta_offset - data_offset;
-    }
-    if (data_fd == journal.fd && data_offset < journal.offset)
-    {
-        data_len = data_len < journal.offset-data_offset
-            ? data_len : journal.offset-data_offset;
-    }
-    if (cfg_data_size != 0)
-    {
-        if (data_len < cfg_data_size)
-        {
-            throw std::runtime_error("Data area ("+std::to_string(data_len)+
-                " bytes) is less than configured size ("+std::to_string(cfg_data_size)+" bytes)");
-        }
-        data_len = cfg_data_size;
-    }
-    // meta
-    uint64_t meta_area_size = (meta_fd == data_fd ? data_device_size : meta_device_size) - meta_offset;
-    if (meta_fd == data_fd && meta_offset <= data_offset)
-    {
-        meta_area_size = data_offset - meta_offset;
-    }
-    if (meta_fd == journal.fd && meta_offset <= journal.offset)
-    {
-        meta_area_size = meta_area_size < journal.offset-meta_offset
-            ? meta_area_size : journal.offset-meta_offset;
-    }
-    // journal
-    journal.len = (journal.fd == data_fd ? data_device_size : (journal.fd == meta_fd ? meta_device_size : journal.device_size)) - journal.offset;
-    if (journal.fd == data_fd && journal.offset <= data_offset)
-    {
-        journal.len = data_offset - journal.offset;
-    }
-    if (journal.fd == meta_fd && journal.offset <= meta_offset)
-    {
-        journal.len = journal.len < meta_offset-journal.offset
-            ? journal.len : meta_offset-journal.offset;
-    }
-    // required metadata size
-    block_count = data_len / data_block_size;
-    meta_len = (1 + (block_count - 1 + meta_block_size / clean_entry_size) / (meta_block_size / clean_entry_size)) * meta_block_size;
-    if (meta_area_size < meta_len)
-    {
-        throw std::runtime_error("Metadata area is too small, need at least "+std::to_string(meta_len)+" bytes");
-    }
+    dsk.calc_lengths();
+    journal.len = dsk.journal_len;
+    journal.block_size = dsk.journal_block_size;
+    journal.offset = dsk.journal_offset;
     if (inmemory_meta)
     {
-        metadata_buffer = memalign(MEM_ALIGNMENT, meta_len);
+        metadata_buffer = memalign(MEM_ALIGNMENT, dsk.meta_len);
         if (!metadata_buffer)
             throw std::runtime_error("Failed to allocate memory for the metadata");
     }
-    else if (clean_entry_bitmap_size)
+    else if (dsk.clean_entry_bitmap_size)
     {
-        clean_bitmap = (uint8_t*)malloc(block_count * 2*clean_entry_bitmap_size);
+        clean_bitmap = (uint8_t*)malloc(dsk.block_count * 2*dsk.clean_entry_bitmap_size);
         if (!clean_bitmap)
             throw std::runtime_error("Failed to allocate memory for the metadata sparse write bitmap");
     }
-    // requested journal size
-    if (cfg_journal_size > journal.len)
-    {
-        throw std::runtime_error("Requested journal_size is too large");
-    }
-    else if (cfg_journal_size > 0)
-    {
-        journal.len = cfg_journal_size;
-    }
-    if (journal.len < MIN_JOURNAL_SIZE)
-    {
-        throw std::runtime_error("Journal is too small, need at least "+std::to_string(MIN_JOURNAL_SIZE)+" bytes");
-    }
     if (journal.inmemory)
     {
         journal.buffer = memalign(MEM_ALIGNMENT, journal.len);
         if (!journal.buffer)
             throw std::runtime_error("Failed to allocate memory for journal");
     }
-}
-
-static void check_size(int fd, uint64_t *size, uint64_t *sectsize, std::string name)
-{
-    int sect;
-    struct stat st;
-    if (fstat(fd, &st) < 0)
-    {
-        throw std::runtime_error("Failed to stat "+name);
-    }
-    if (S_ISREG(st.st_mode))
-    {
-        *size = st.st_size;
-        if (sectsize)
-        {
-            *sectsize = st.st_blksize;
-        }
-    }
-    else if (S_ISBLK(st.st_mode))
-    {
-        if (ioctl(fd, BLKGETSIZE64, size) < 0 ||
-            ioctl(fd, BLKSSZGET, &sect) < 0)
-        {
-            throw std::runtime_error("Failed to get "+name+" size or block size: "+strerror(errno));
-        }
-        if (sectsize)
-        {
-            *sectsize = sect;
-        }
-    }
     else
     {
-        throw std::runtime_error(name+" is neither a file nor a block device");
-    }
-}
-
-void blockstore_impl_t::open_data()
-{
-    data_fd = open(data_device.c_str(), O_DIRECT|O_RDWR);
-    if (data_fd == -1)
-    {
-        throw std::runtime_error("Failed to open data device");
-    }
-    check_size(data_fd, &data_device_size, &data_device_sect, "data device");
-    if (disk_alignment % data_device_sect)
-    {
-        throw std::runtime_error(
-            "disk_alignment ("+std::to_string(disk_alignment)+
-            ") is not a multiple of data device sector size ("+std::to_string(data_device_sect)+")"
-        );
-    }
-    if (data_offset >= data_device_size)
-    {
-        throw std::runtime_error("data_offset exceeds device size = "+std::to_string(data_device_size));
-    }
-    if (!disable_flock && flock(data_fd, LOCK_EX|LOCK_NB) != 0)
-    {
-        throw std::runtime_error(std::string("Failed to lock data device: ") + strerror(errno));
-    }
-}
-
-void blockstore_impl_t::open_meta()
-{
-    if (meta_device != "")
-    {
-        meta_offset = 0;
-        meta_fd = open(meta_device.c_str(), O_DIRECT|O_RDWR);
-        if (meta_fd == -1)
-        {
-            throw std::runtime_error("Failed to open metadata device");
-        }
-        check_size(meta_fd, &meta_device_size, &meta_device_sect, "metadata device");
-        if (meta_offset >= meta_device_size)
-        {
-            throw std::runtime_error("meta_offset exceeds device size = "+std::to_string(meta_device_size));
-        }
-        if (!disable_flock && flock(meta_fd, LOCK_EX|LOCK_NB) != 0)
-        {
-            throw std::runtime_error(std::string("Failed to lock metadata device: ") + strerror(errno));
-        }
-    }
-    else
-    {
-        meta_fd = data_fd;
-        meta_device_sect = data_device_sect;
-        meta_device_size = 0;
-        if (meta_offset >= data_device_size)
-        {
-            throw std::runtime_error("meta_offset exceeds device size = "+std::to_string(data_device_size));
-        }
-    }
-    if (meta_block_size % meta_device_sect)
-    {
-        throw std::runtime_error(
-            "meta_block_size ("+std::to_string(meta_block_size)+
-            ") is not a multiple of data device sector size ("+std::to_string(meta_device_sect)+")"
-        );
-    }
-}
-
-void blockstore_impl_t::open_journal()
-{
-    if (journal_device != "")
-    {
-        journal.fd = open(journal_device.c_str(), O_DIRECT|O_RDWR);
-        if (journal.fd == -1)
-        {
-            throw std::runtime_error("Failed to open journal device");
-        }
-        check_size(journal.fd, &journal.device_size, &journal_device_sect, "journal device");
-        if (!disable_flock && flock(journal.fd, LOCK_EX|LOCK_NB) != 0)
-        {
-            throw std::runtime_error(std::string("Failed to lock journal device: ") + strerror(errno));
-        }
-    }
-    else
-    {
-        journal.fd = meta_fd;
-        journal_device_sect = meta_device_sect;
-        journal.device_size = 0;
-        if (journal.offset >= data_device_size)
-        {
-            throw std::runtime_error("journal_offset exceeds device size");
-        }
+        journal.sector_buf = (uint8_t*)memalign(MEM_ALIGNMENT, journal.sector_count * dsk.journal_block_size);
+        if (!journal.sector_buf)
+            throw std::bad_alloc();
     }
     journal.sector_info = (journal_sector_info_t*)calloc(journal.sector_count, sizeof(journal_sector_info_t));
     if (!journal.sector_info)
     {
         throw std::bad_alloc();
     }
-    if (!journal.inmemory)
-    {
-        journal.sector_buf = (uint8_t*)memalign(MEM_ALIGNMENT, journal.sector_count * journal_block_size);
-        if (!journal.sector_buf)
-            throw std::bad_alloc();
-    }
-    if (journal_block_size % journal_device_sect)
-    {
-        throw std::runtime_error(
-            "journal_block_size ("+std::to_string(journal_block_size)+
-            ") is not a multiple of journal device sector size ("+std::to_string(journal_device_sect)+")"
-        );
-    }
 }
diff --git a/src/blockstore_read.cpp b/src/blockstore_read.cpp
index eb53cf5a..b50f4b54 100644
--- a/src/blockstore_read.cpp
+++ b/src/blockstore_read.cpp
@@ -32,9 +32,9 @@ int blockstore_impl_t::fulfill_read_push(blockstore_op_t *op, void *buf, uint64_
     PRIV(op)->pending_ops++;
     my_uring_prep_readv(
         sqe,
-        IS_JOURNAL(item_state) ? journal.fd : data_fd,
+        IS_JOURNAL(item_state) ? dsk.journal_fd : dsk.data_fd,
         &data->iov, 1,
-        (IS_JOURNAL(item_state) ? journal.offset : data_offset) + offset
+        (IS_JOURNAL(item_state) ? dsk.journal_offset : dsk.data_offset) + offset
     );
     data->callback = [this, op](ring_data_t *data) { handle_read_event(data, op); };
     return 1;
@@ -97,15 +97,15 @@ endwhile:
 uint8_t* blockstore_impl_t::get_clean_entry_bitmap(uint64_t block_loc, int offset)
 {
     uint8_t *clean_entry_bitmap;
-    uint64_t meta_loc = block_loc >> block_order;
+    uint64_t meta_loc = block_loc >> dsk.block_order;
     if (inmemory_meta)
     {
-        uint64_t sector = (meta_loc / (meta_block_size / clean_entry_size)) * meta_block_size;
-        uint64_t pos = (meta_loc % (meta_block_size / clean_entry_size));
-        clean_entry_bitmap = ((uint8_t*)metadata_buffer + sector + pos*clean_entry_size + sizeof(clean_disk_entry) + offset);
+        uint64_t sector = (meta_loc / (dsk.meta_block_size / dsk.clean_entry_size)) * dsk.meta_block_size;
+        uint64_t pos = (meta_loc % (dsk.meta_block_size / dsk.clean_entry_size));
+        clean_entry_bitmap = ((uint8_t*)metadata_buffer + sector + pos*dsk.clean_entry_size + sizeof(clean_disk_entry) + offset);
     }
     else
-        clean_entry_bitmap = (uint8_t*)(clean_bitmap + meta_loc*2*clean_entry_bitmap_size + offset);
+        clean_entry_bitmap = (uint8_t*)(clean_bitmap + meta_loc*2*dsk.clean_entry_bitmap_size + offset);
     return clean_entry_bitmap;
 }
 
@@ -152,8 +152,8 @@ int blockstore_impl_t::dequeue_read(blockstore_op_t *read_op)
                     result_version = dirty_it->first.version;
                     if (read_op->bitmap)
                     {
-                        void *bmp_ptr = (clean_entry_bitmap_size > sizeof(void*) ? dirty_it->second.bitmap : &dirty_it->second.bitmap);
-                        memcpy(read_op->bitmap, bmp_ptr, clean_entry_bitmap_size);
+                        void *bmp_ptr = (dsk.clean_entry_bitmap_size > sizeof(void*) ? dirty_it->second.bitmap : &dirty_it->second.bitmap);
+                        memcpy(read_op->bitmap, bmp_ptr, dsk.clean_entry_bitmap_size);
                     }
                 }
                 if (!fulfill_read(read_op, fulfilled, dirty.offset, dirty.offset + dirty.len,
@@ -178,15 +178,15 @@ int blockstore_impl_t::dequeue_read(blockstore_op_t *read_op)
             result_version = clean_it->second.version;
             if (read_op->bitmap)
             {
-                void *bmp_ptr = get_clean_entry_bitmap(clean_it->second.location, clean_entry_bitmap_size);
-                memcpy(read_op->bitmap, bmp_ptr, clean_entry_bitmap_size);
+                void *bmp_ptr = get_clean_entry_bitmap(clean_it->second.location, dsk.clean_entry_bitmap_size);
+                memcpy(read_op->bitmap, bmp_ptr, dsk.clean_entry_bitmap_size);
             }
         }
         if (fulfilled < read_op->len)
         {
-            if (!clean_entry_bitmap_size)
+            if (!dsk.clean_entry_bitmap_size)
             {
-                if (!fulfill_read(read_op, fulfilled, 0, data_block_size, (BS_ST_BIG_WRITE | BS_ST_STABLE), 0, clean_it->second.location))
+                if (!fulfill_read(read_op, fulfilled, 0, dsk.data_block_size, (BS_ST_BIG_WRITE | BS_ST_STABLE), 0, clean_it->second.location))
                 {
                     // need to wait. undo added requests, don't dequeue op
                     PRIV(read_op)->read_vec.clear();
@@ -196,7 +196,7 @@ int blockstore_impl_t::dequeue_read(blockstore_op_t *read_op)
             else
             {
                 uint8_t *clean_entry_bitmap = get_clean_entry_bitmap(clean_it->second.location, 0);
-                uint64_t bmp_start = 0, bmp_end = 0, bmp_size = data_block_size/bitmap_granularity;
+                uint64_t bmp_start = 0, bmp_end = 0, bmp_size = dsk.data_block_size/dsk.bitmap_granularity;
                 while (bmp_start < bmp_size)
                 {
                     while (!(clean_entry_bitmap[bmp_end >> 3] & (1 << (bmp_end & 0x7))) && bmp_end < bmp_size)
@@ -206,8 +206,8 @@ int blockstore_impl_t::dequeue_read(blockstore_op_t *read_op)
                     if (bmp_end > bmp_start)
                     {
                         // fill with zeroes
-                        assert(fulfill_read(read_op, fulfilled, bmp_start * bitmap_granularity,
-                            bmp_end * bitmap_granularity, (BS_ST_DELETE | BS_ST_STABLE), 0, 0));
+                        assert(fulfill_read(read_op, fulfilled, bmp_start * dsk.bitmap_granularity,
+                            bmp_end * dsk.bitmap_granularity, (BS_ST_DELETE | BS_ST_STABLE), 0, 0));
                     }
                     bmp_start = bmp_end;
                     while (clean_entry_bitmap[bmp_end >> 3] & (1 << (bmp_end & 0x7)) && bmp_end < bmp_size)
@@ -216,9 +216,9 @@ int blockstore_impl_t::dequeue_read(blockstore_op_t *read_op)
                     }
                     if (bmp_end > bmp_start)
                     {
-                        if (!fulfill_read(read_op, fulfilled, bmp_start * bitmap_granularity,
-                            bmp_end * bitmap_granularity, (BS_ST_BIG_WRITE | BS_ST_STABLE), 0,
-                            clean_it->second.location + bmp_start * bitmap_granularity))
+                        if (!fulfill_read(read_op, fulfilled, bmp_start * dsk.bitmap_granularity,
+                            bmp_end * dsk.bitmap_granularity, (BS_ST_BIG_WRITE | BS_ST_STABLE), 0,
+                            clean_it->second.location + bmp_start * dsk.bitmap_granularity))
                         {
                             // need to wait. undo added requests, don't dequeue op
                             PRIV(read_op)->read_vec.clear();
@@ -233,7 +233,7 @@ int blockstore_impl_t::dequeue_read(blockstore_op_t *read_op)
     else if (fulfilled < read_op->len)
     {
         // fill remaining parts with zeroes
-        assert(fulfill_read(read_op, fulfilled, 0, data_block_size, (BS_ST_DELETE | BS_ST_STABLE), 0, 0));
+        assert(fulfill_read(read_op, fulfilled, 0, dsk.data_block_size, (BS_ST_DELETE | BS_ST_STABLE), 0, 0));
     }
     assert(fulfilled == read_op->len);
     read_op->version = result_version;
@@ -288,8 +288,8 @@ int blockstore_impl_t::read_bitmap(object_id oid, uint64_t target_version, void
                     *result_version = dirty_it->first.version;
                 if (bitmap)
                 {
-                    void *bmp_ptr = (clean_entry_bitmap_size > sizeof(void*) ? dirty_it->second.bitmap : &dirty_it->second.bitmap);
-                    memcpy(bitmap, bmp_ptr, clean_entry_bitmap_size);
+                    void *bmp_ptr = (dsk.clean_entry_bitmap_size > sizeof(void*) ? dirty_it->second.bitmap : &dirty_it->second.bitmap);
+                    memcpy(bitmap, bmp_ptr, dsk.clean_entry_bitmap_size);
                 }
                 return 0;
             }
@@ -306,14 +306,14 @@ int blockstore_impl_t::read_bitmap(object_id oid, uint64_t target_version, void
             *result_version = clean_it->second.version;
         if (bitmap)
         {
-            void *bmp_ptr = get_clean_entry_bitmap(clean_it->second.location, clean_entry_bitmap_size);
-            memcpy(bitmap, bmp_ptr, clean_entry_bitmap_size);
+            void *bmp_ptr = get_clean_entry_bitmap(clean_it->second.location, dsk.clean_entry_bitmap_size);
+            memcpy(bitmap, bmp_ptr, dsk.clean_entry_bitmap_size);
         }
         return 0;
     }
     if (result_version)
         *result_version = 0;
     if (bitmap)
-        memset(bitmap, 0, clean_entry_bitmap_size);
+        memset(bitmap, 0, dsk.clean_entry_bitmap_size);
     return -ENOENT;
 }
diff --git a/src/blockstore_rollback.cpp b/src/blockstore_rollback.cpp
index 3349c761..f07655da 100644
--- a/src/blockstore_rollback.cpp
+++ b/src/blockstore_rollback.cpp
@@ -112,7 +112,7 @@ resume_2:
     if (!disable_journal_fsync)
     {
         BS_SUBMIT_GET_SQE(sqe, data);
-        my_uring_prep_fsync(sqe, journal.fd, IORING_FSYNC_DATASYNC);
+        my_uring_prep_fsync(sqe, dsk.journal_fd, IORING_FSYNC_DATASYNC);
         data->iov = { 0 };
         data->callback = [this, op](ring_data_t *data) { handle_write_event(data, op); };
         PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 0;
@@ -217,10 +217,10 @@ void blockstore_impl_t::erase_dirty(blockstore_dirty_db_t::iterator dirty_start,
             dirty_it->second.location != UINT64_MAX)
         {
 #ifdef BLOCKSTORE_DEBUG
-            printf("Free block %lu from %lx:%lx v%lu\n", dirty_it->second.location >> block_order,
+            printf("Free block %lu from %lx:%lx v%lu\n", dirty_it->second.location >> dsk.block_order,
                 dirty_it->first.oid.inode, dirty_it->first.oid.stripe, dirty_it->first.version);
 #endif
-            data_alloc->set(dirty_it->second.location >> block_order, false);
+            data_alloc->set(dirty_it->second.location >> dsk.block_order, false);
         }
         int used = --journal.used_sectors[dirty_it->second.journal_sector];
 #ifdef BLOCKSTORE_DEBUG
@@ -233,7 +233,7 @@ void blockstore_impl_t::erase_dirty(blockstore_dirty_db_t::iterator dirty_start,
         {
             journal.used_sectors.erase(dirty_it->second.journal_sector);
         }
-        if (clean_entry_bitmap_size > sizeof(void*))
+        if (dsk.clean_entry_bitmap_size > sizeof(void*))
         {
             free(dirty_it->second.bitmap);
             dirty_it->second.bitmap = NULL;
diff --git a/src/blockstore_stable.cpp b/src/blockstore_stable.cpp
index 3a91b8d2..34be29ec 100644
--- a/src/blockstore_stable.cpp
+++ b/src/blockstore_stable.cpp
@@ -137,7 +137,7 @@ resume_2:
     if (!disable_journal_fsync)
     {
         BS_SUBMIT_GET_SQE(sqe, data);
-        my_uring_prep_fsync(sqe, journal.fd, IORING_FSYNC_DATASYNC);
+        my_uring_prep_fsync(sqe, dsk.journal_fd, IORING_FSYNC_DATASYNC);
         data->iov = { 0 };
         data->callback = [this, op](ring_data_t *data) { handle_write_event(data, op); };
         PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 0;
@@ -195,14 +195,14 @@ void blockstore_impl_t::mark_stable(const obj_ver_id & v, bool forget_dirty)
                     }
                     if (!exists)
                     {
-                        inode_space_stats[dirty_it->first.oid.inode] += data_block_size;
+                        inode_space_stats[dirty_it->first.oid.inode] += dsk.data_block_size;
                     }
                 }
                 else if (IS_DELETE(dirty_it->second.state))
                 {
                     auto & sp = inode_space_stats[dirty_it->first.oid.inode];
-                    if (sp > data_block_size)
-                        sp -= data_block_size;
+                    if (sp > dsk.data_block_size)
+                        sp -= dsk.data_block_size;
                     else
                         inode_space_stats.erase(dirty_it->first.oid.inode);
                 }
diff --git a/src/blockstore_sync.cpp b/src/blockstore_sync.cpp
index ce238780..ddacff16 100644
--- a/src/blockstore_sync.cpp
+++ b/src/blockstore_sync.cpp
@@ -60,7 +60,7 @@ int blockstore_impl_t::continue_sync(blockstore_op_t *op, bool queue_has_in_prog
         if (!disable_data_fsync)
         {
             BS_SUBMIT_GET_SQE(sqe, data);
-            my_uring_prep_fsync(sqe, data_fd, IORING_FSYNC_DATASYNC);
+            my_uring_prep_fsync(sqe, dsk.data_fd, IORING_FSYNC_DATASYNC);
             data->iov = { 0 };
             data->callback = [this, op](ring_data_t *data) { handle_write_event(data, op); };
             PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 0;
@@ -79,7 +79,7 @@ int blockstore_impl_t::continue_sync(blockstore_op_t *op, bool queue_has_in_prog
         // Check space in the journal and journal memory buffers
         blockstore_journal_check_t space_check(this);
         if (!space_check.check_available(op, PRIV(op)->sync_big_writes.size(),
-            sizeof(journal_entry_big_write) + clean_entry_bitmap_size, JOURNAL_STABILIZE_RESERVATION))
+            sizeof(journal_entry_big_write) + dsk.clean_entry_bitmap_size, JOURNAL_STABILIZE_RESERVATION))
         {
             return 0;
         }
@@ -90,7 +90,7 @@ int blockstore_impl_t::continue_sync(blockstore_op_t *op, bool queue_has_in_prog
         int s = 0;
         while (it != PRIV(op)->sync_big_writes.end())
         {
-            if (!journal.entry_fits(sizeof(journal_entry_big_write) + clean_entry_bitmap_size) &&
+            if (!journal.entry_fits(sizeof(journal_entry_big_write) + dsk.clean_entry_bitmap_size) &&
                 journal.sector_info[journal.cur_sector].dirty)
             {
                 prepare_journal_sector_write(journal.cur_sector, op);
@@ -99,7 +99,7 @@ int blockstore_impl_t::continue_sync(blockstore_op_t *op, bool queue_has_in_prog
             auto & dirty_entry = dirty_db.at(*it);
             journal_entry_big_write *je = (journal_entry_big_write*)prefill_single_journal_entry(
                 journal, (dirty_entry.state & BS_ST_INSTANT) ? JE_BIG_WRITE_INSTANT : JE_BIG_WRITE,
-                sizeof(journal_entry_big_write) + clean_entry_bitmap_size
+                sizeof(journal_entry_big_write) + dsk.clean_entry_bitmap_size
             );
             dirty_entry.journal_sector = journal.sector_info[journal.cur_sector].offset;
             journal.used_sectors[journal.sector_info[journal.cur_sector].offset]++;
@@ -115,8 +115,8 @@ int blockstore_impl_t::continue_sync(blockstore_op_t *op, bool queue_has_in_prog
             je->offset = dirty_entry.offset;
             je->len = dirty_entry.len;
             je->location = dirty_entry.location;
-            memcpy((void*)(je+1), (clean_entry_bitmap_size > sizeof(void*)
-                ? dirty_entry.bitmap : &dirty_entry.bitmap), clean_entry_bitmap_size);
+            memcpy((void*)(je+1), (dsk.clean_entry_bitmap_size > sizeof(void*)
+                ? dirty_entry.bitmap : &dirty_entry.bitmap), dsk.clean_entry_bitmap_size);
             je->crc32 = je_crc32((journal_entry*)je);
             journal.crc32_last = je->crc32;
             it++;
@@ -132,7 +132,7 @@ int blockstore_impl_t::continue_sync(blockstore_op_t *op, bool queue_has_in_prog
         if (!disable_journal_fsync)
         {
             BS_SUBMIT_GET_SQE(sqe, data);
-            my_uring_prep_fsync(sqe, journal.fd, IORING_FSYNC_DATASYNC);
+            my_uring_prep_fsync(sqe, dsk.journal_fd, IORING_FSYNC_DATASYNC);
             data->iov = { 0 };
             data->callback = [this, op](ring_data_t *data) { handle_write_event(data, op); };
             PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 0;
diff --git a/src/blockstore_write.cpp b/src/blockstore_write.cpp
index e1a633af..233d7733 100644
--- a/src/blockstore_write.cpp
+++ b/src/blockstore_write.cpp
@@ -10,9 +10,9 @@ bool blockstore_impl_t::enqueue_write(blockstore_op_t *op)
     bool wait_big = false, wait_del = false;
     void *bmp = NULL;
     uint64_t version = 1;
-    if (!is_del && clean_entry_bitmap_size > sizeof(void*))
+    if (!is_del && dsk.clean_entry_bitmap_size > sizeof(void*))
     {
-        bmp = calloc_or_die(1, clean_entry_bitmap_size);
+        bmp = calloc_or_die(1, dsk.clean_entry_bitmap_size);
     }
     if (dirty_db.size() > 0)
     {
@@ -32,8 +32,8 @@ bool blockstore_impl_t::enqueue_write(blockstore_op_t *op)
                 : ((dirty_it->second.state & BS_ST_WORKFLOW_MASK) == BS_ST_WAIT_BIG);
             if (!is_del && !deleted)
             {
-                if (clean_entry_bitmap_size > sizeof(void*))
-                    memcpy(bmp, dirty_it->second.bitmap, clean_entry_bitmap_size);
+                if (dsk.clean_entry_bitmap_size > sizeof(void*))
+                    memcpy(bmp, dirty_it->second.bitmap, dsk.clean_entry_bitmap_size);
                 else
                     bmp = dirty_it->second.bitmap;
             }
@@ -48,8 +48,8 @@ bool blockstore_impl_t::enqueue_write(blockstore_op_t *op)
             version = clean_it->second.version + 1;
             if (!is_del)
             {
-                void *bmp_ptr = get_clean_entry_bitmap(clean_it->second.location, clean_entry_bitmap_size);
-                memcpy((clean_entry_bitmap_size > sizeof(void*) ? bmp : &bmp), bmp_ptr, clean_entry_bitmap_size);
+                void *bmp_ptr = get_clean_entry_bitmap(clean_it->second.location, dsk.clean_entry_bitmap_size);
+                memcpy((dsk.clean_entry_bitmap_size > sizeof(void*) ? bmp : &bmp), bmp_ptr, dsk.clean_entry_bitmap_size);
             }
         }
         else
@@ -90,14 +90,14 @@ bool blockstore_impl_t::enqueue_write(blockstore_op_t *op)
         {
             // Invalid version requested
             op->retval = -EEXIST;
-            if (!is_del && clean_entry_bitmap_size > sizeof(void*))
+            if (!is_del && dsk.clean_entry_bitmap_size > sizeof(void*))
             {
                 free(bmp);
             }
             return false;
         }
     }
-    if (wait_big && !is_del && !deleted && op->len < data_block_size &&
+    if (wait_big && !is_del && !deleted && op->len < dsk.data_block_size &&
         immediate_commit != IMMEDIATE_ALL)
     {
         // Issue an additional sync so that the previous big write can reach the journal
@@ -122,7 +122,7 @@ bool blockstore_impl_t::enqueue_write(blockstore_op_t *op)
         state = BS_ST_DELETE | BS_ST_IN_FLIGHT;
     else
     {
-        state = (op->len == data_block_size || deleted ? BS_ST_BIG_WRITE : BS_ST_SMALL_WRITE);
+        state = (op->len == dsk.data_block_size || deleted ? BS_ST_BIG_WRITE : BS_ST_SMALL_WRITE);
         if (state == BS_ST_SMALL_WRITE && throttle_small_writes)
             clock_gettime(CLOCK_REALTIME, &PRIV(op)->tv_begin);
         if (wait_del)
@@ -136,9 +136,9 @@ bool blockstore_impl_t::enqueue_write(blockstore_op_t *op)
         if (op->bitmap)
         {
             // Only allow to overwrite part of the object bitmap respective to the write's offset/len
-            uint8_t *bmp_ptr = (uint8_t*)(clean_entry_bitmap_size > sizeof(void*) ? bmp : &bmp);
-            uint32_t bit = op->offset/bitmap_granularity;
-            uint32_t bits_left = op->len/bitmap_granularity;
+            uint8_t *bmp_ptr = (uint8_t*)(dsk.clean_entry_bitmap_size > sizeof(void*) ? bmp : &bmp);
+            uint32_t bit = op->offset/dsk.bitmap_granularity;
+            uint32_t bits_left = op->len/dsk.bitmap_granularity;
             while (!(bit % 8) && bits_left > 8)
             {
                 // Copy bytes
@@ -175,7 +175,7 @@ void blockstore_impl_t::cancel_all_writes(blockstore_op_t *op, blockstore_dirty_
 {
     while (dirty_it != dirty_db.end() && dirty_it->first.oid == op->oid)
     {
-        if (clean_entry_bitmap_size > sizeof(void*))
+        if (dsk.clean_entry_bitmap_size > sizeof(void*))
             free(dirty_it->second.bitmap);
         dirty_db.erase(dirty_it++);
     }
@@ -251,7 +251,7 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
     {
         blockstore_journal_check_t space_check(this);
         if (!space_check.check_available(op, unsynced_big_write_count + 1,
-            sizeof(journal_entry_big_write) + clean_entry_bitmap_size, JOURNAL_STABILIZE_RESERVATION))
+            sizeof(journal_entry_big_write) + dsk.clean_entry_bitmap_size, JOURNAL_STABILIZE_RESERVATION))
         {
             return 0;
         }
@@ -271,7 +271,7 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
         }
         BS_SUBMIT_GET_SQE(sqe, data);
         write_iodepth++;
-        dirty_it->second.location = loc << block_order;
+        dirty_it->second.location = loc << dsk.block_order;
         dirty_it->second.state = (dirty_it->second.state & ~BS_ST_WORKFLOW_MASK) | BS_ST_SUBMITTED;
 #ifdef BLOCKSTORE_DEBUG
         printf(
@@ -280,9 +280,9 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
         );
 #endif
         data_alloc->set(loc, true);
-        uint64_t stripe_offset = (op->offset % bitmap_granularity);
-        uint64_t stripe_end = (op->offset + op->len) % bitmap_granularity;
-        // Zero fill up to bitmap_granularity
+        uint64_t stripe_offset = (op->offset % dsk.bitmap_granularity);
+        uint64_t stripe_end = (op->offset + op->len) % dsk.bitmap_granularity;
+        // Zero fill up to dsk.bitmap_granularity
         int vcnt = 0;
         if (stripe_offset)
         {
@@ -291,13 +291,13 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
         PRIV(op)->iov_zerofill[vcnt++] = (struct iovec){ op->buf, op->len };
         if (stripe_end)
         {
-            stripe_end = bitmap_granularity - stripe_end;
+            stripe_end = dsk.bitmap_granularity - stripe_end;
             PRIV(op)->iov_zerofill[vcnt++] = (struct iovec){ zero_object, stripe_end };
         }
         data->iov.iov_len = op->len + stripe_offset + stripe_end; // to check it in the callback
         data->callback = [this, op](ring_data_t *data) { handle_write_event(data, op); };
         my_uring_prep_writev(
-            sqe, data_fd, PRIV(op)->iov_zerofill, vcnt, data_offset + (loc << block_order) + op->offset - stripe_offset
+            sqe, dsk.data_fd, PRIV(op)->iov_zerofill, vcnt, dsk.data_offset + (loc << dsk.block_order) + op->offset - stripe_offset
         );
         PRIV(op)->pending_ops = 1;
         PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 0;
@@ -319,9 +319,9 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
         blockstore_journal_check_t space_check(this);
         if (unsynced_big_write_count &&
             !space_check.check_available(op, unsynced_big_write_count,
-                sizeof(journal_entry_big_write) + clean_entry_bitmap_size, 0)
+                sizeof(journal_entry_big_write) + dsk.clean_entry_bitmap_size, 0)
             || !space_check.check_available(op, 1,
-                sizeof(journal_entry_small_write) + clean_entry_bitmap_size, op->len + JOURNAL_STABILIZE_RESERVATION))
+                sizeof(journal_entry_small_write) + dsk.clean_entry_bitmap_size, op->len + JOURNAL_STABILIZE_RESERVATION))
         {
             return 0;
         }
@@ -329,7 +329,7 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
         BS_SUBMIT_CHECK_SQES(
             // Write current journal sector only if it's dirty and full, or in the immediate_commit mode
             (immediate_commit != IMMEDIATE_NONE ||
-                !journal.entry_fits(sizeof(journal_entry_small_write) + clean_entry_bitmap_size) ? 1 : 0) +
+                !journal.entry_fits(sizeof(journal_entry_small_write) + dsk.clean_entry_bitmap_size) ? 1 : 0) +
             (op->len > 0 ? 1 : 0)
         );
         write_iodepth++;
@@ -337,7 +337,7 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
         auto cb = [this, op](ring_data_t *data) { handle_write_event(data, op); };
         if (immediate_commit == IMMEDIATE_NONE)
         {
-            if (!journal.entry_fits(sizeof(journal_entry_small_write) + clean_entry_bitmap_size))
+            if (!journal.entry_fits(sizeof(journal_entry_small_write) + dsk.clean_entry_bitmap_size))
             {
                 prepare_journal_sector_write(journal.cur_sector, op);
             }
@@ -349,7 +349,7 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
         // Then pre-fill journal entry
         journal_entry_small_write *je = (journal_entry_small_write*)prefill_single_journal_entry(
             journal, op->opcode == BS_OP_WRITE_STABLE ? JE_SMALL_WRITE_INSTANT : JE_SMALL_WRITE,
-            sizeof(journal_entry_small_write) + clean_entry_bitmap_size
+            sizeof(journal_entry_small_write) + dsk.clean_entry_bitmap_size
         );
         dirty_it->second.journal_sector = journal.sector_info[journal.cur_sector].offset;
         journal.used_sectors[journal.sector_info[journal.cur_sector].offset]++;
@@ -361,14 +361,14 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
         );
 #endif
         // Figure out where data will be
-        journal.next_free = (journal.next_free + op->len) <= journal.len ? journal.next_free : journal_block_size;
+        journal.next_free = (journal.next_free + op->len) <= journal.len ? journal.next_free : dsk.journal_block_size;
         je->oid = op->oid;
         je->version = op->version;
         je->offset = op->offset;
         je->len = op->len;
         je->data_offset = journal.next_free;
         je->crc32_data = crc32c(0, op->buf, op->len);
-        memcpy((void*)(je+1), (clean_entry_bitmap_size > sizeof(void*) ? dirty_it->second.bitmap : &dirty_it->second.bitmap), clean_entry_bitmap_size);
+        memcpy((void*)(je+1), (dsk.clean_entry_bitmap_size > sizeof(void*) ? dirty_it->second.bitmap : &dirty_it->second.bitmap), dsk.clean_entry_bitmap_size);
         je->crc32 = je_crc32((journal_entry*)je);
         journal.crc32_last = je->crc32;
         if (immediate_commit != IMMEDIATE_NONE)
@@ -387,7 +387,7 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
             data2->iov = (struct iovec){ op->buf, op->len };
             data2->callback = cb;
             my_uring_prep_writev(
-                sqe2, journal.fd, &data2->iov, 1, journal.offset + journal.next_free
+                sqe2, dsk.journal_fd, &data2->iov, 1, journal.offset + journal.next_free
             );
             PRIV(op)->pending_ops++;
         }
@@ -400,7 +400,7 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
         journal.next_free += op->len;
         if (journal.next_free >= journal.len)
         {
-            journal.next_free = journal_block_size;
+            journal.next_free = dsk.journal_block_size;
         }
         if (!PRIV(op)->pending_ops)
         {
@@ -440,7 +440,7 @@ resume_2:
         assert(dirty_it != dirty_db.end());
         journal_entry_big_write *je = (journal_entry_big_write*)prefill_single_journal_entry(
             journal, op->opcode == BS_OP_WRITE_STABLE ? JE_BIG_WRITE_INSTANT : JE_BIG_WRITE,
-            sizeof(journal_entry_big_write) + clean_entry_bitmap_size
+            sizeof(journal_entry_big_write) + dsk.clean_entry_bitmap_size
         );
         dirty_it->second.journal_sector = journal.sector_info[journal.cur_sector].offset;
         journal.used_sectors[journal.sector_info[journal.cur_sector].offset]++;
@@ -456,7 +456,7 @@ resume_2:
         je->offset = op->offset;
         je->len = op->len;
         je->location = dirty_it->second.location;
-        memcpy((void*)(je+1), (clean_entry_bitmap_size > sizeof(void*) ? dirty_it->second.bitmap : &dirty_it->second.bitmap), clean_entry_bitmap_size);
+        memcpy((void*)(je+1), (dsk.clean_entry_bitmap_size > sizeof(void*) ? dirty_it->second.bitmap : &dirty_it->second.bitmap), dsk.clean_entry_bitmap_size);
         je->crc32 = je_crc32((journal_entry*)je);
         journal.crc32_last = je->crc32;
         prepare_journal_sector_write(journal.cur_sector, op);
@@ -634,7 +634,7 @@ int blockstore_impl_t::dequeue_del(blockstore_op_t *op)
     // Write current journal sector only if it's dirty and full, or in the immediate_commit mode
     BS_SUBMIT_CHECK_SQES(
         (immediate_commit != IMMEDIATE_NONE ||
-            (journal_block_size - journal.in_sector_pos) < sizeof(journal_entry_del) &&
+            (dsk.journal_block_size - journal.in_sector_pos) < sizeof(journal_entry_del) &&
             journal.sector_info[journal.cur_sector].dirty) ? 1 : 0
     );
     if (write_iodepth >= max_write_iodepth)
@@ -645,7 +645,7 @@ int blockstore_impl_t::dequeue_del(blockstore_op_t *op)
     // Prepare journal sector write
     if (immediate_commit == IMMEDIATE_NONE)
     {
-        if ((journal_block_size - journal.in_sector_pos) < sizeof(journal_entry_del) &&
+        if ((dsk.journal_block_size - journal.in_sector_pos) < sizeof(journal_entry_del) &&
             journal.sector_info[journal.cur_sector].dirty)
         {
             prepare_journal_sector_write(journal.cur_sector, op);