libblock: Change bdbuf API

The functions
 o rtems_bdbuf_get(),
 o rtems_bdbuf_read(),
 o rtems_bdbuf_syncdev(), and
 o rtems_bdbuf_purge_dev(),
use now the disk device instead of the device identifier.  This makes
bdbuf independent of rtems_disk_obtain() and rtems_disk_release().  It
is the responsiblity of the file system to obtain the disk device.  This
also reduces the overhead to get a buffer.

The key for the AVL tree uses now the disk device instead of the device
identifier.  The pointer is interpreted as an unsigned integer.  This
reduces the memory overhead and makes the comparison operation a bit
faster.

Removed function rtems_bdbuf_purge_major().  This function was too
destructive and could have unpredictable side effects.

17 files changed, 275 insertions, 312 deletions

diff --git a/cpukit/libblock/include/rtems/bdbuf.h b/cpukit/libblock/include/rtems/bdbuf.h
index 37e06aa9e9..254c745c7a 100644
--- a/cpukit/libblock/include/rtems/bdbuf.h
+++ b/cpukit/libblock/include/rtems/bdbuf.h
@@ -301,7 +301,7 @@ typedef struct rtems_bdbuf_group rtems_bdbuf_group;
  * To manage buffers we using buffer descriptors (BD). A BD holds a buffer plus
  * a range of other information related to managing the buffer in the cache. To
  * speed-up buffer lookup descriptors are organized in AVL-Tree. The fields
- * 'dev' and 'block' are search keys.
+ * 'dd' and 'block' are search keys.
  */
 typedef struct rtems_bdbuf_buffer
 {
@@ -315,7 +315,7 @@ typedef struct rtems_bdbuf_buffer
     signed char                bal;    /**< The balance of the sub-tree */
   } avl;
 
-  dev_t             dev;        /**< device number */
+  const rtems_disk_device *dd;  /**< disk device */
 
   rtems_blkdev_bnum block;      /**< block number on the device */
 
@@ -470,8 +470,7 @@ rtems_bdbuf_init (void);
  * The block number is the linear block number. This is relative to the start
  * of the partition on the media.
  *
- * @param device [in] Device number (constructed of major and minor device
- * number).
+ * @param dd [in] The disk device.
  * @param block [in] Linear media block number.
  * @param bd [out] Reference to the buffer descriptor pointer.
  *
@@ -481,7 +480,11 @@ rtems_bdbuf_init (void);
  * @retval RTEMS_INVALID_NUMBER Invalid block size.
  */
 rtems_status_code
-rtems_bdbuf_get (dev_t device, rtems_blkdev_bnum block, rtems_bdbuf_buffer** bd);
+rtems_bdbuf_get (
+  const rtems_disk_device *dd,
+  rtems_blkdev_bnum block,
+  rtems_bdbuf_buffer** bd
+);
 
 /**
  * Get the block buffer and if not already in the cache read from the disk. If
@@ -498,8 +501,7 @@ rtems_bdbuf_get (dev_t device, rtems_blkdev_bnum block, rtems_bdbuf_buffer** bd)
  * buffer is returned. The highest priority waiter will obtain the buffer
  * first.
  *
- * @param device [in] Device number (constructed of major and minor device
- * number).
+ * @param dd [in] The disk device.
  * @param block [in] Linear media block number.
  * @param bd [out] Reference to the buffer descriptor pointer.
  *
@@ -510,7 +512,11 @@ rtems_bdbuf_get (dev_t device, rtems_blkdev_bnum block, rtems_bdbuf_buffer** bd)
  * @retval RTEMS_IO_ERROR IO error.
  */
 rtems_status_code
-rtems_bdbuf_read (dev_t device, rtems_blkdev_bnum block, rtems_bdbuf_buffer** bd);
+rtems_bdbuf_read (
+  const rtems_disk_device *dd,
+  rtems_blkdev_bnum block,
+  rtems_bdbuf_buffer** bd
+);
 
 /**
  * Release the buffer obtained by a read call back to the cache. If the buffer
@@ -575,31 +581,22 @@ rtems_bdbuf_sync (rtems_bdbuf_buffer* bd);
  * @note Nesting calls to sync multiple devices will be handled sequentially. A
  * nested call will be blocked until the first sync request has complete.
  *
- * @param dev [in] Device number (constructed of major and minor device
- * number).
+ * @param dd [in] The disk device.
  *
  * @retval RTEMS_SUCCESSFUL Successful operation. 
  * @retval RTEMS_NOT_CONFIGURED Not initialized.
  * @retval RTEMS_INVALID_ID No such device.
  */
 rtems_status_code
-rtems_bdbuf_syncdev (dev_t dev);
+rtems_bdbuf_syncdev (const rtems_disk_device *dd);
 
 /**
- * @brief Purges all buffers that matches the device identifier @a dev.
+ * @brief Purges all buffers corresponding to the disk device @a dd.
  *
  * This may result in loss of data.
  */
 void
-rtems_bdbuf_purge_dev (dev_t dev);
-
-/**
- * @brief Purges all buffers that matches the device major number @a major.
- *
- * This may result in loss of data.
- */
-void
-rtems_bdbuf_purge_major (rtems_device_major_number major);
+rtems_bdbuf_purge_dev (const rtems_disk_device *dd);
 
 /** @} */
 
diff --git a/cpukit/libblock/include/rtems/bdpart.h b/cpukit/libblock/include/rtems/bdpart.h
index 907866eb43..873b9d31f6 100644
--- a/cpukit/libblock/include/rtems/bdpart.h
+++ b/cpukit/libblock/include/rtems/bdpart.h
@@ -7,12 +7,13 @@
  */
 
 /*
- * Copyright (c) 2009, 2010
- * embedded brains GmbH
- * Obere Lagerstr. 30
- * D-82178 Puchheim
- * Germany
- * <rtems@embedded-brains.de>
+ * Copyright (c) 2009-2012 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Obere Lagerstr. 30
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
  *
  * The license and distribution terms for this file may be
  * found in the file LICENSE in this distribution or at
@@ -398,7 +399,8 @@ static inline uint8_t rtems_bdpart_mbr_partition_type(
 
 rtems_status_code rtems_bdpart_get_disk_data(
   const char *disk_name,
-  dev_t *disk,
+  int *fd_ptr,
+  const rtems_disk_device **dd_ptr,
   rtems_blkdev_bnum *disk_end
 );
 
diff --git a/cpukit/libblock/src/bdbuf.c b/cpukit/libblock/src/bdbuf.c
index 53782e80fc..a5eaa9560d 100644
--- a/cpukit/libblock/src/bdbuf.c
+++ b/cpukit/libblock/src/bdbuf.c
@@ -19,7 +19,7 @@
  *    Rewritten to remove score mutex access. Fixes many performance
  *    issues.
  *
- * Copyright (c) 2009 embedded brains GmbH.
+ * Copyright (c) 2009-2012 embedded brains GmbH.
  *
  * @(#) bdbuf.c,v 1.14 2004/04/17 08:15:17 ralf Exp
  */
@@ -44,7 +44,7 @@
 
 #include "rtems/bdbuf.h"
 
-#define BDBUF_INVALID_DEV ((dev_t) -1)
+#define BDBUF_INVALID_DEV NULL
 
 /*
  * Simpler label for this file.
@@ -58,7 +58,7 @@
 typedef struct rtems_bdbuf_swapout_transfer
 {
   rtems_chain_control   bds;         /**< The transfer list of BDs. */
-  dev_t                 dev;         /**< The device the transfer is for. */
+  const rtems_disk_device *dd;       /**< The device the transfer is for. */
   bool                  syncing;     /**< The data is a sync'ing. */
   rtems_blkdev_request* write_req;   /**< The write request array. */
   uint32_t              bufs_per_bd; /**< Number of buffers per bd. */
@@ -113,7 +113,7 @@ typedef struct rtems_bdbuf_cache
   rtems_id            sync_lock;         /**< Sync calls block writes. */
   bool                sync_active;       /**< True if a sync is active. */
   rtems_id            sync_requester;    /**< The sync requester. */
-  dev_t               sync_device;       /**< The device to sync and
+  const rtems_disk_device *sync_device;  /**< The device to sync and
                                           * BDBUF_INVALID_DEV not a device
                                           * sync. */
 
@@ -174,7 +174,6 @@ typedef struct rtems_bdbuf_cache
 #define RTEMS_BLKDEV_FATAL_BDBUF_STATE_0       RTEMS_BLKDEV_FATAL_ERROR(28)
 #define RTEMS_BLKDEV_FATAL_BDBUF_STATE_1       RTEMS_BLKDEV_FATAL_ERROR(29)
 #define RTEMS_BLKDEV_FATAL_BDBUF_STATE_2       RTEMS_BLKDEV_FATAL_ERROR(30)
-#define RTEMS_BLKDEV_FATAL_BDBUF_DISK_REL      RTEMS_BLKDEV_FATAL_ERROR(31)
 
 /**
  * The events used in this code. These should be system events rather than
@@ -322,24 +321,25 @@ rtems_bdbuf_fatal (rtems_bdbuf_buf_state state, uint32_t error)
 }
 
 /**
- * Searches for the node with specified dev/block.
+ * Searches for the node with specified dd/block.
  *
  * @param root pointer to the root node of the AVL-Tree
- * @param dev device search key
+ * @param dd disk device search key
  * @param block block search key
- * @retval NULL node with the specified dev/block is not found
- * @return pointer to the node with specified dev/block
+ * @retval NULL node with the specified dd/block is not found
+ * @return pointer to the node with specified dd/block
  */
 static rtems_bdbuf_buffer *
 rtems_bdbuf_avl_search (rtems_bdbuf_buffer** root,
-                        dev_t                dev,
+                        const rtems_disk_device *dd,
                         rtems_blkdev_bnum    block)
 {
   rtems_bdbuf_buffer* p = *root;
 
-  while ((p != NULL) && ((p->dev != dev) || (p->block != block)))
+  while ((p != NULL) && ((p->dd != dd) || (p->block != block)))
   {
-    if ((p->dev < dev) || ((p->dev == dev) && (p->block < block)))
+    if (((uintptr_t) p->dd < (uintptr_t) dd)
+        || ((p->dd == dd) && (p->block < block)))
     {
       p = p->avl.right;
     }
@@ -364,7 +364,7 @@ static int
 rtems_bdbuf_avl_insert(rtems_bdbuf_buffer** root,
                        rtems_bdbuf_buffer*  node)
 {
-  dev_t             dev = node->dev;
+  const rtems_disk_device *dd = node->dd;
   rtems_blkdev_bnum block = node->block;
 
   rtems_bdbuf_buffer*  p = *root;
@@ -389,7 +389,8 @@ rtems_bdbuf_avl_insert(rtems_bdbuf_buffer** root,
   {
     *buf_prev++ = p;
 
-    if ((p->dev < dev) || ((p->dev == dev) && (p->block < block)))
+    if (((uintptr_t) p->dd < (uintptr_t) dd)
+        || ((p->dd == dd) && (p->block < block)))
     {
       p->avl.cache = 1;
       q = p->avl.right;
@@ -400,7 +401,7 @@ rtems_bdbuf_avl_insert(rtems_bdbuf_buffer** root,
         break;
       }
     }
-    else if ((p->dev != dev) || (p->block != block))
+    else if ((p->dd != dd) || (p->block != block))
     {
       p->avl.cache = -1;
       q = p->avl.left;
@@ -545,7 +546,7 @@ static int
 rtems_bdbuf_avl_remove(rtems_bdbuf_buffer**      root,
                        const rtems_bdbuf_buffer* node)
 {
-  dev_t             dev = node->dev;
+  const rtems_disk_device *dd = node->dd;
   rtems_blkdev_bnum block = node->block;
 
   rtems_bdbuf_buffer*  p = *root;
@@ -565,12 +566,13 @@ rtems_bdbuf_avl_remove(rtems_bdbuf_buffer**      root,
   {
     *buf_prev++ = p;
 
-    if ((p->dev < dev) || ((p->dev == dev) && (p->block < block)))
+    if (((uintptr_t) p->dd < (uintptr_t) dd)
+        || ((p->dd == dd) && (p->block < block)))
     {
       p->avl.cache = 1;
       p = p->avl.right;
     }
-    else if ((p->dev != dev) || (p->block != block))
+    else if ((p->dd != dd) || (p->block != block))
     {
       p->avl.cache = -1;
       p = p->avl.left;
@@ -1092,7 +1094,7 @@ rtems_bdbuf_discard_buffer (rtems_bdbuf_buffer *bd)
 static void
 rtems_bdbuf_add_to_modified_list_after_access (rtems_bdbuf_buffer *bd)
 {
-  if (bdbuf_cache.sync_active && bdbuf_cache.sync_device == bd->dev)
+  if (bdbuf_cache.sync_active && bdbuf_cache.sync_device == bd->dd)
   {
     rtems_bdbuf_unlock_cache ();
 
@@ -1221,10 +1223,10 @@ rtems_bdbuf_group_realloc (rtems_bdbuf_group* group, size_t new_bds_per_group)
 
 static void
 rtems_bdbuf_setup_empty_buffer (rtems_bdbuf_buffer *bd,
-                                dev_t               dev,
+                                const rtems_disk_device *dd,
                                 rtems_blkdev_bnum   block)
 {
-  bd->dev       = dev;
+  bd->dd        = dd ;
   bd->block     = block;
   bd->avl.left  = NULL;
   bd->avl.right = NULL;
@@ -1237,7 +1239,7 @@ rtems_bdbuf_setup_empty_buffer (rtems_bdbuf_buffer *bd,
 }
 
 static rtems_bdbuf_buffer *
-rtems_bdbuf_get_buffer_from_lru_list (dev_t             dev,
+rtems_bdbuf_get_buffer_from_lru_list (const rtems_disk_device *dd,
                                       rtems_blkdev_bnum block,
                                       size_t            bds_per_group)
 {
@@ -1271,7 +1273,7 @@ rtems_bdbuf_get_buffer_from_lru_list (dev_t             dev,
 
     if (empty_bd != NULL)
     {
-      rtems_bdbuf_setup_empty_buffer (empty_bd, dev, block);
+      rtems_bdbuf_setup_empty_buffer (empty_bd, dd, block);
 
       return empty_bd;
     }
@@ -1422,7 +1424,7 @@ rtems_bdbuf_init (void)
        b < bdbuf_cache.buffer_min_count;
        b++, bd++, buffer += bdbuf_config.buffer_min)
   {
-    bd->dev    = BDBUF_INVALID_DEV;
+    bd->dd    = BDBUF_INVALID_DEV;
     bd->group  = group;
     bd->buffer = buffer;
 
@@ -1668,17 +1670,17 @@ rtems_bdbuf_sync_after_access (rtems_bdbuf_buffer *bd)
 }
 
 static rtems_bdbuf_buffer *
-rtems_bdbuf_get_buffer_for_read_ahead (dev_t             dev,
+rtems_bdbuf_get_buffer_for_read_ahead (const rtems_disk_device *dd,
                                        rtems_blkdev_bnum block,
                                        size_t            bds_per_group)
 {
   rtems_bdbuf_buffer *bd = NULL;
 
-  bd = rtems_bdbuf_avl_search (&bdbuf_cache.tree, dev, block);
+  bd = rtems_bdbuf_avl_search (&bdbuf_cache.tree, dd, block);
 
   if (bd == NULL)
   {
-    bd = rtems_bdbuf_get_buffer_from_lru_list (dev, block, bds_per_group);
+    bd = rtems_bdbuf_get_buffer_from_lru_list (dd, block, bds_per_group);
 
     if (bd != NULL)
       rtems_bdbuf_group_obtain (bd);
@@ -1694,7 +1696,7 @@ rtems_bdbuf_get_buffer_for_read_ahead (dev_t             dev,
 }
 
 static rtems_bdbuf_buffer *
-rtems_bdbuf_get_buffer_for_access (dev_t             dev,
+rtems_bdbuf_get_buffer_for_access (const rtems_disk_device *dd,
                                    rtems_blkdev_bnum block,
                                    size_t            bds_per_group)
 {
@@ -1702,7 +1704,7 @@ rtems_bdbuf_get_buffer_for_access (dev_t             dev,
 
   do
   {
-    bd = rtems_bdbuf_avl_search (&bdbuf_cache.tree, dev, block);
+    bd = rtems_bdbuf_avl_search (&bdbuf_cache.tree, dd, block);
 
     if (bd != NULL)
     {
@@ -1719,7 +1721,7 @@ rtems_bdbuf_get_buffer_for_access (dev_t             dev,
     }
     else
     {
-      bd = rtems_bdbuf_get_buffer_from_lru_list (dev, block, bds_per_group);
+      bd = rtems_bdbuf_get_buffer_from_lru_list (dd, block, bds_per_group);
 
       if (bd == NULL)
         rtems_bdbuf_wait_for_buffer ();
@@ -1734,26 +1736,14 @@ rtems_bdbuf_get_buffer_for_access (dev_t             dev,
 }
 
 static rtems_status_code
-rtems_bdbuf_obtain_disk (dev_t               dev,
+rtems_bdbuf_obtain_disk (const rtems_disk_device *dd,
                          rtems_blkdev_bnum   block,
-                         rtems_disk_device **dd_ptr,
                          rtems_blkdev_bnum  *media_block_ptr,
                          size_t             *bds_per_group_ptr)
 {
-  rtems_disk_device *dd = NULL;
-
   if (!bdbuf_cache.initialised)
     return RTEMS_NOT_CONFIGURED;
 
-  /*
-   * Do not hold the cache lock when obtaining the disk table.
-   */
-  dd = rtems_disk_obtain (dev);
-  if (dd == NULL)
-    return RTEMS_INVALID_ID;
-
-  *dd_ptr = dd;
-
   if (media_block_ptr != NULL)
   {
     /*
@@ -1766,7 +1756,6 @@ rtems_bdbuf_obtain_disk (dev_t               dev,
                                                     dd->media_block_size);
     if (mb >= dd->size)
     {
-      rtems_disk_release(dd);
       return RTEMS_INVALID_NUMBER;
     }
 
@@ -1779,7 +1768,6 @@ rtems_bdbuf_obtain_disk (dev_t               dev,
 
     if (bds_per_group == 0)
     {
-      rtems_disk_release (dd);
       return RTEMS_INVALID_NUMBER;
     }
 
@@ -1789,28 +1777,17 @@ rtems_bdbuf_obtain_disk (dev_t               dev,
   return RTEMS_SUCCESSFUL;
 }
 
-static void
-rtems_bdbuf_release_disk (rtems_disk_device *dd)
-{
-  rtems_status_code sc = RTEMS_SUCCESSFUL;
-
-  sc = rtems_disk_release (dd);
-  if (sc != RTEMS_SUCCESSFUL)
-    rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_DISK_REL);
-}
-
 rtems_status_code
-rtems_bdbuf_get (dev_t                dev,
+rtems_bdbuf_get (const rtems_disk_device *dd,
                  rtems_blkdev_bnum    block,
                  rtems_bdbuf_buffer **bd_ptr)
 {
   rtems_status_code   sc = RTEMS_SUCCESSFUL;
-  rtems_disk_device  *dd = NULL;
   rtems_bdbuf_buffer *bd = NULL;
   rtems_blkdev_bnum   media_block = 0;
   size_t              bds_per_group = 0;
 
-  sc = rtems_bdbuf_obtain_disk (dev, block, &dd, &media_block, &bds_per_group);
+  sc = rtems_bdbuf_obtain_disk (dd, block, &media_block, &bds_per_group);
   if (sc != RTEMS_SUCCESSFUL)
     return sc;
 
@@ -1821,9 +1798,9 @@ rtems_bdbuf_get (dev_t                dev,
    */
   if (rtems_bdbuf_tracer)
     printf ("bdbuf:get: %" PRIu32 " (%" PRIu32 ") (dev = %08x)\n",
-            media_block, block, (unsigned) dev);
+            media_block, block, (unsigned) dd->dev);
 
-  bd = rtems_bdbuf_get_buffer_for_access (dev, media_block, bds_per_group);
+  bd = rtems_bdbuf_get_buffer_for_access (dd, media_block, bds_per_group);
 
   switch (bd->state)
   {
@@ -1856,8 +1833,6 @@ rtems_bdbuf_get (dev_t                dev,
 
   rtems_bdbuf_unlock_cache ();
 
-  rtems_bdbuf_release_disk (dd);
-
   *bd_ptr = bd;
 
   return RTEMS_SUCCESSFUL;
@@ -1892,7 +1867,6 @@ rtems_bdbuf_create_read_request (const rtems_disk_device *dd,
   rtems_bdbuf_buffer *bd = NULL;
   rtems_blkdev_bnum   media_block_end = dd->start + dd->size;
   rtems_blkdev_bnum   media_block_count = dd->block_size / dd->media_block_size;
-  dev_t               dev = dd->dev;
   uint32_t            block_size = dd->block_size;
   uint32_t            transfer_index = 1;
   uint32_t            transfer_count = bdbuf_config.max_read_ahead_blocks + 1;
@@ -1907,7 +1881,7 @@ rtems_bdbuf_create_read_request (const rtems_disk_device *dd,
   req->status = RTEMS_RESOURCE_IN_USE;
   req->bufnum = 0;
 
-  bd = rtems_bdbuf_get_buffer_for_access (dev, media_block, bds_per_group);
+  bd = rtems_bdbuf_get_buffer_for_access (dd, media_block, bds_per_group);
 
   *bd_ptr = bd;
 
@@ -1936,7 +1910,7 @@ rtems_bdbuf_create_read_request (const rtems_disk_device *dd,
   {
     media_block += media_block_count;
 
-    bd = rtems_bdbuf_get_buffer_for_read_ahead (dev, media_block,
+    bd = rtems_bdbuf_get_buffer_for_read_ahead (dd, media_block,
                                                 bds_per_group);
 
     if (bd == NULL)
@@ -2021,18 +1995,17 @@ rtems_bdbuf_execute_transfer_request (const rtems_disk_device *dd,
 }
 
 rtems_status_code
-rtems_bdbuf_read (dev_t                dev,
+rtems_bdbuf_read (const rtems_disk_device *dd,
                   rtems_blkdev_bnum    block,
                   rtems_bdbuf_buffer **bd_ptr)
 {
   rtems_status_code     sc = RTEMS_SUCCESSFUL;
-  rtems_disk_device    *dd = NULL;
   rtems_blkdev_request *req = NULL;
   rtems_bdbuf_buffer   *bd = NULL;
   rtems_blkdev_bnum     media_block = 0;
   size_t                bds_per_group = 0;
 
-  sc = rtems_bdbuf_obtain_disk (dev, block, &dd, &media_block, &bds_per_group);
+  sc = rtems_bdbuf_obtain_disk (dd, block, &media_block, &bds_per_group);
   if (sc != RTEMS_SUCCESSFUL)
     return sc;
 
@@ -2047,7 +2020,7 @@ rtems_bdbuf_read (dev_t                dev,
 
   if (rtems_bdbuf_tracer)
     printf ("bdbuf:read: %" PRIu32 " (%" PRIu32 ") (dev = %08x)\n",
-            media_block + dd->start, block, (unsigned) dev);
+            media_block + dd->start, block, (unsigned) dd->dev);
 
   rtems_bdbuf_lock_cache ();
   rtems_bdbuf_create_read_request (dd, media_block, bds_per_group, req, &bd);
@@ -2089,7 +2062,6 @@ rtems_bdbuf_read (dev_t                dev,
     *bd_ptr = NULL;
 
   rtems_bdbuf_unlock_cache ();
-  rtems_bdbuf_release_disk (dd);
 
   return sc;
 }
@@ -2210,15 +2182,14 @@ rtems_bdbuf_sync (rtems_bdbuf_buffer *bd)
 }
 
 rtems_status_code
-rtems_bdbuf_syncdev (dev_t dev)
+rtems_bdbuf_syncdev (const rtems_disk_device *dd)
 {
   rtems_status_code  sc = RTEMS_SUCCESSFUL;
-  rtems_disk_device *dd = NULL;
 
   if (rtems_bdbuf_tracer)
-    printf ("bdbuf:syncdev: %08x\n", (unsigned) dev);
+    printf ("bdbuf:syncdev: %08x\n", (unsigned) dd->dev);
 
-  sc = rtems_bdbuf_obtain_disk (dev, 0, &dd, NULL, NULL);
+  sc = rtems_bdbuf_obtain_disk (dd, 0, NULL, NULL);
   if (sc != RTEMS_SUCCESSFUL)
     return sc;
 
@@ -2240,23 +2211,16 @@ rtems_bdbuf_syncdev (dev_t dev)
    */
   bdbuf_cache.sync_active    = true;
   bdbuf_cache.sync_requester = rtems_task_self ();
-  bdbuf_cache.sync_device    = dev;
+  bdbuf_cache.sync_device    = dd;
 
   rtems_bdbuf_wake_swapper ();
   rtems_bdbuf_unlock_cache ();
   rtems_bdbuf_wait_for_event (RTEMS_BDBUF_TRANSFER_SYNC);
   rtems_bdbuf_unlock_sync ();
-  rtems_bdbuf_release_disk (dd);
 
   return RTEMS_SUCCESSFUL;
 }
 
-static int
-rtems_bdbuf_null_disk_ioctl (rtems_disk_device *dd, uint32_t req, void *arg)
-{
-  return -1;
-}
-
 /**
  * Swapout transfer to the driver. The driver will break this I/O into groups
  * of consecutive write requests is multiple consecutive buffers are required
@@ -2268,14 +2232,9 @@ static void
 rtems_bdbuf_swapout_write (rtems_bdbuf_swapout_transfer* transfer)
 {
   rtems_chain_node *node;
-  static rtems_disk_device null_disk = {
-    .phys_dev = &null_disk,
-    .capabilities = 0,
-    .ioctl = rtems_bdbuf_null_disk_ioctl
-  };
 
   if (rtems_bdbuf_tracer)
-    printf ("bdbuf:swapout transfer: %08x\n", (unsigned) transfer->dev);
+    printf ("bdbuf:swapout transfer: %08x\n", (unsigned) transfer->dd->dev);
 
   /*
    * If there are buffers to transfer to the media transfer them.
@@ -2294,14 +2253,7 @@ rtems_bdbuf_swapout_write (rtems_bdbuf_swapout_transfer* transfer)
      */
     uint32_t bufs_per_bd = 0;
 
-    /*
-     * Obtain the disk device. The cache's mutex has been released to avoid a
-     * dead lock.
-     */
-    rtems_disk_device *dd = rtems_disk_obtain (transfer->dev);
-
-    if (dd == NULL)
-      dd = &null_disk;
+    const rtems_disk_device *dd = transfer->dd;
 
     bufs_per_bd = dd->block_size / bdbuf_config.buffer_min;
 
@@ -2372,20 +2324,15 @@ rtems_bdbuf_swapout_write (rtems_bdbuf_swapout_transfer* transfer)
       }
     }
 
-    if (dd != &null_disk)
+    /*
+     * If sync'ing and the deivce is capability of handling a sync IO control
+     * call perform the call.
+     */
+    if (transfer->syncing &&
+        (dd->phys_dev->capabilities & RTEMS_BLKDEV_CAP_SYNC))
     {
-      /*
-       * If sync'ing and the deivce is capability of handling a sync IO control
-       * call perform the call.
-       */
-      if (transfer->syncing &&
-          (dd->phys_dev->capabilities & RTEMS_BLKDEV_CAP_SYNC))
-      {
-        /* int result = */ dd->ioctl (dd->phys_dev, RTEMS_BLKDEV_REQ_SYNC, NULL);
-        /* How should the error be handled ? */
-      }
-      
-      rtems_disk_release (dd);
+      /* int result = */ dd->ioctl (dd->phys_dev, RTEMS_BLKDEV_REQ_SYNC, NULL);
+      /* How should the error be handled ? */
     }
   }
 }
@@ -2394,8 +2341,9 @@ rtems_bdbuf_swapout_write (rtems_bdbuf_swapout_transfer* transfer)
  * Process the modified list of buffers. There is a sync or modified list that
  * needs to be handled so we have a common function to do the work.
  *
- * @param dev The device to handle. If BDBUF_INVALID_DEV no device is selected
- * so select the device of the first buffer to be written to disk.
+ * @param dd_ptr Pointer to the device to handle. If BDBUF_INVALID_DEV no
+ * device is selected so select the device of the first buffer to be written to
+ * disk.
  * @param chain The modified chain to process.
  * @param transfer The chain to append buffers to be written too.
  * @param sync_active If true this is a sync operation so expire all timers.
@@ -2404,7 +2352,7 @@ rtems_bdbuf_swapout_write (rtems_bdbuf_swapout_transfer* transfer)
  *                    amount.
  */
 static void
-rtems_bdbuf_swapout_modified_processing (dev_t*               dev,
+rtems_bdbuf_swapout_modified_processing (const rtems_disk_device **dd_ptr,
                                          rtems_chain_control* chain,
                                          rtems_chain_control* transfer,
                                          bool                 sync_active,
@@ -2421,7 +2369,7 @@ rtems_bdbuf_swapout_modified_processing (dev_t*               dev,
     /*
      * A sync active with no valid dev means sync all.
      */
-    if (sync_active && (*dev == BDBUF_INVALID_DEV))
+    if (sync_active && (*dd_ptr == BDBUF_INVALID_DEV))
       sync_all = true;
     else
       sync_all = false;
@@ -2437,7 +2385,7 @@ rtems_bdbuf_swapout_modified_processing (dev_t*               dev,
        * @note Lots of sync requests will skew this timer. It should be based
        *       on TOD to be accurate. Does it matter ?
        */
-      if (sync_all || (sync_active && (*dev == bd->dev))
+      if (sync_all || (sync_active && (*dd_ptr == bd->dd))
           || rtems_bdbuf_has_buffer_waiters ())
         bd->hold_timer = 0;
 
@@ -2459,14 +2407,14 @@ rtems_bdbuf_swapout_modified_processing (dev_t*               dev,
       }
 
       /*
-       * This assumes we can set dev_t to BDBUF_INVALID_DEV which is just an
+       * This assumes we can set it to BDBUF_INVALID_DEV which is just an
        * assumption. Cannot use the transfer list being empty the sync dev
        * calls sets the dev to use.
        */
-      if (*dev == BDBUF_INVALID_DEV)
-        *dev = bd->dev;
+      if (*dd_ptr == BDBUF_INVALID_DEV)
+        *dd_ptr = bd->dd;
 
-      if (bd->dev == *dev)
+      if (bd->dd == *dd_ptr)
       {
         rtems_chain_node* next_node = node->next;
         rtems_chain_node* tnode = rtems_chain_tail (transfer);
@@ -2556,7 +2504,7 @@ rtems_bdbuf_swapout_processing (unsigned long                 timer_delta,
   }
 
   rtems_chain_initialize_empty (&transfer->bds);
-  transfer->dev = BDBUF_INVALID_DEV;
+  transfer->dd = BDBUF_INVALID_DEV;
   transfer->syncing = bdbuf_cache.sync_active;
   
   /*
@@ -2565,13 +2513,13 @@ rtems_bdbuf_swapout_processing (unsigned long                 timer_delta,
    * list. This means the dev is BDBUF_INVALID_DEV.
    */
   if (bdbuf_cache.sync_active)
-    transfer->dev = bdbuf_cache.sync_device;
+    transfer->dd = bdbuf_cache.sync_device;
     
   /*
    * If we have any buffers in the sync queue move them to the modified
    * list. The first sync buffer will select the device we use.
    */
-  rtems_bdbuf_swapout_modified_processing (&transfer->dev,
+  rtems_bdbuf_swapout_modified_processing (&transfer->dd,
                                            &bdbuf_cache.sync,
                                            &transfer->bds,
                                            true, false,
@@ -2580,7 +2528,7 @@ rtems_bdbuf_swapout_processing (unsigned long                 timer_delta,
   /*
    * Process the cache's modified list.
    */
-  rtems_bdbuf_swapout_modified_processing (&transfer->dev,
+  rtems_bdbuf_swapout_modified_processing (&transfer->dd,
                                            &bdbuf_cache.modified,
                                            &transfer->bds,
                                            bdbuf_cache.sync_active,
@@ -2678,7 +2626,7 @@ rtems_bdbuf_swapout_worker_task (rtems_task_argument arg)
     rtems_bdbuf_lock_cache ();
 
     rtems_chain_initialize_empty (&worker->transfer.bds);
-    worker->transfer.dev = BDBUF_INVALID_DEV;
+    worker->transfer.dd = BDBUF_INVALID_DEV;
 
     rtems_chain_append (&bdbuf_cache.swapout_workers, &worker->link);
 
@@ -2715,7 +2663,7 @@ rtems_bdbuf_swapout_workers_open (void)
     worker->transfer.write_req = rtems_bdbuf_swapout_writereq_alloc ();
 
     rtems_chain_initialize_empty (&worker->transfer.bds);
-    worker->transfer.dev = BDBUF_INVALID_DEV;
+    worker->transfer.dd = BDBUF_INVALID_DEV;
 
     sc = rtems_task_create (rtems_build_name('B', 'D', 'o', 'a' + w),
                             (bdbuf_config.swapout_priority ?
@@ -2777,7 +2725,7 @@ rtems_bdbuf_swapout_task (rtems_task_argument arg)
 
   transfer.write_req = rtems_bdbuf_swapout_writereq_alloc ();
   rtems_chain_initialize_empty (&transfer.bds);
-  transfer.dev = BDBUF_INVALID_DEV;
+  transfer.dd = BDBUF_INVALID_DEV;
   transfer.syncing = false;
 
   /*
@@ -2871,12 +2819,9 @@ rtems_bdbuf_purge_list (rtems_chain_control *purge_list)
     rtems_bdbuf_wake (&bdbuf_cache.buffer_waiters);
 }
 
-typedef bool (*rtems_bdbuf_purge_compare)(dev_t a, dev_t b);
-
 static void
 rtems_bdbuf_gather_for_purge (rtems_chain_control *purge_list,
-                              rtems_bdbuf_purge_compare compare,
-                              dev_t dev)
+                              const rtems_disk_device *dd)
 {
   rtems_bdbuf_buffer *stack [RTEMS_BDBUF_AVL_MAX_HEIGHT];
   rtems_bdbuf_buffer **prev = stack;
@@ -2886,7 +2831,7 @@ rtems_bdbuf_gather_for_purge (rtems_chain_control *purge_list,
 
   while (cur != NULL)
   {
-    if ((*compare) (cur->dev, dev))
+    if (cur->dd == dd)
     {
       switch (cur->state)
       {
@@ -2950,40 +2895,14 @@ rtems_bdbuf_gather_for_purge (rtems_chain_control *purge_list,
   }
 }
 
-static void
-rtems_bdbuf_purge (rtems_bdbuf_purge_compare compare, dev_t dev)
+void
+rtems_bdbuf_purge_dev (const rtems_disk_device *dd)
 {
   rtems_chain_control purge_list;
 
   rtems_chain_initialize_empty (&purge_list);
   rtems_bdbuf_lock_cache ();
-  rtems_bdbuf_gather_for_purge (&purge_list, compare, dev);
+  rtems_bdbuf_gather_for_purge (&purge_list, dd);
   rtems_bdbuf_purge_list (&purge_list);
   rtems_bdbuf_unlock_cache ();
 }
-
-static bool
-rtems_bdbuf_purge_compare_dev (dev_t a, dev_t b)
-{
-  return a == b;
-}
-
-void
-rtems_bdbuf_purge_dev (dev_t dev)
-{
-  rtems_bdbuf_purge (rtems_bdbuf_purge_compare_dev, dev);
-}
-
-static bool
-rtems_bdbuf_purge_compare_major (dev_t a, dev_t b)
-{
-  return rtems_filesystem_dev_major_t (a) == rtems_filesystem_dev_major_t (b);
-}
-
-void
-rtems_bdbuf_purge_major (rtems_device_major_number major)
-{
-  dev_t dev = rtems_filesystem_make_dev_t (major, 0);
-
-  rtems_bdbuf_purge (rtems_bdbuf_purge_compare_major, dev);
-}
diff --git a/cpukit/libblock/src/bdpart-create.c b/cpukit/libblock/src/bdpart-create.c
index dc93522c19..209f78ff31 100644
--- a/cpukit/libblock/src/bdpart-create.c
+++ b/cpukit/libblock/src/bdpart-create.c
@@ -45,7 +45,6 @@ rtems_status_code rtems_bdpart_create(
     dos_compatibility ? RTEMS_BDPART_MBR_CYLINDER_SIZE : 1;
   rtems_blkdev_bnum overhead = 0;
   rtems_blkdev_bnum free_space = 0;
-  dev_t disk = 0;
   size_t i = 0;
 
   /* Check if we have something to do */
@@ -60,7 +59,7 @@ rtems_status_code rtems_bdpart_create(
   }
 
   /* Get disk data */
-  sc = rtems_bdpart_get_disk_data( disk_name, &disk, &disk_end);
+  sc = rtems_bdpart_get_disk_data( disk_name, NULL, NULL, &disk_end);
   if (sc != RTEMS_SUCCESSFUL) {
     return sc;
   }
@@ -142,15 +141,15 @@ rtems_status_code rtems_bdpart_create(
     /* Align partition upwards */
     s += record_space - (s % record_space);
 
+    /* Reserve space for the EBR if necessary */
+    if (count > 4 && i > 2) {
+      pos += record_space;
+    }
+
     /* Partition begin and end */
     p->begin = pos;
     pos += s;
     p->end = pos;
-
-    /* Reserve space for the EBR if necessary */
-    if (count > 4 && i > 2) {
-      p->begin += record_space;
-    }
   }
 
   /* Expand the last partition to the disk end */
diff --git a/cpukit/libblock/src/bdpart-read.c b/cpukit/libblock/src/bdpart-read.c
index 3560dbd3a3..4604e1080b 100644
--- a/cpukit/libblock/src/bdpart-read.c
+++ b/cpukit/libblock/src/bdpart-read.c
@@ -23,6 +23,9 @@
 #include "config.h"
 #endif
 
+#include <sys/stat.h>
+#include <fcntl.h>
+
 #include <rtems.h>
 #include <rtems/bdbuf.h>
 #include <rtems/bdpart.h>
@@ -64,48 +67,59 @@ bool rtems_bdpart_to_mbr_partition_type(
  */
 rtems_status_code rtems_bdpart_get_disk_data(
   const char *disk_name,
-  dev_t *disk,
+  int *fd_ptr,
+  const rtems_disk_device **dd_ptr,
   rtems_blkdev_bnum *disk_end
 )
 {
   rtems_status_code sc = RTEMS_SUCCESSFUL;
   int rv = 0;
+  int fd = -1;
+  const rtems_disk_device *dd = NULL;
   rtems_blkdev_bnum disk_begin = 0;
   rtems_blkdev_bnum block_size = 0;
-  rtems_disk_device *dd = NULL;
-  struct stat st;
+
+  /* Open device file */
+  fd = open( disk_name, O_RDWR);
+  if (fd < 0) {
+    sc = RTEMS_INVALID_NAME;
+    goto error;
+  }
 
   /* Get disk handle */
-  rv = stat( disk_name, &st);
+  rv = rtems_disk_fd_get_disk_device( fd, &dd);
   if (rv != 0) {
-    return RTEMS_INVALID_NAME;
+    sc = RTEMS_INVALID_NAME;
+    goto error;
   }
-  *disk = st.st_rdev;
 
   /* Get disk begin, end and block size */
-  dd = rtems_disk_obtain( *disk);
-  if (dd == NULL) {
-    return RTEMS_INVALID_NAME;
-  }
   disk_begin = dd->start;
   *disk_end = dd->size;
   block_size = dd->block_size;
-  sc = rtems_disk_release( dd);
-  if (sc != RTEMS_SUCCESSFUL) {
-    return sc;
-  }
 
   /* Check block size */
   if (block_size < RTEMS_BDPART_BLOCK_SIZE) {
-    return RTEMS_IO_ERROR;
+    sc = RTEMS_IO_ERROR;
+    goto error;
   }
 
   /* Check that we have do not have a logical disk */
   if (disk_begin != 0) {
-    return RTEMS_IO_ERROR;
+    sc = RTEMS_IO_ERROR;
+    goto error;
   }
 
-  return RTEMS_SUCCESSFUL;
+error:
+
+  if (sc == RTEMS_SUCCESSFUL && fd_ptr != NULL && dd_ptr != NULL) {
+    *fd_ptr = fd;
+    *dd_ptr = dd;
+  } else {
+    close( fd);
+  }
+
+  return sc;
 }
 
 static bool rtems_bdpart_is_valid_record( const uint8_t *data)
@@ -171,7 +185,7 @@ static rtems_status_code rtems_bdpart_read_mbr_partition(
 }
 
 static rtems_status_code rtems_bdpart_read_record(
-  dev_t disk,
+  const rtems_disk_device *dd,
   rtems_blkdev_bnum index,
   rtems_bdbuf_buffer **block
 )
@@ -187,7 +201,7 @@ static rtems_status_code rtems_bdpart_read_record(
   }
 
   /* Read the record block */
-  sc = rtems_bdbuf_read( disk, index, block);
+  sc = rtems_bdbuf_read( dd, index, block);
   if (sc != RTEMS_SUCCESSFUL) {
     return sc;
   }
@@ -220,9 +234,10 @@ rtems_status_code rtems_bdpart_read(
   rtems_blkdev_bnum ep_begin = 0; /* Extended partition begin */
   rtems_blkdev_bnum ebr = 0; /* Extended boot record block index */
   rtems_blkdev_bnum disk_end = 0;
-  dev_t disk = 0;
   size_t i = 0;
   const uint8_t *data = NULL;
+  int fd = -1;
+  const rtems_disk_device *dd = NULL;
 
   /* Check parameter */
   if (format == NULL || pt == NULL || count == NULL) {
@@ -233,13 +248,13 @@ rtems_status_code rtems_bdpart_read(
   *count = 0;
 
   /* Get disk data */
-  sc = rtems_bdpart_get_disk_data( disk_name, &disk, &disk_end);
+  sc = rtems_bdpart_get_disk_data( disk_name, &fd, &dd, &disk_end);
   if (sc != RTEMS_SUCCESSFUL) {
     return sc;
   }
 
   /* Read MBR */
-  sc = rtems_bdpart_read_record( disk, 0, &block);
+  sc = rtems_bdpart_read_record( dd, 0, &block);
   if (sc != RTEMS_SUCCESSFUL) {
     esc = sc;
     goto cleanup;
@@ -283,7 +298,7 @@ rtems_status_code rtems_bdpart_read(
     rtems_blkdev_bnum tmp = 0;
 
     /* Read EBR */
-    sc = rtems_bdpart_read_record( disk, ebr, &block);
+    sc = rtems_bdpart_read_record( dd, ebr, &block);
     if (sc != RTEMS_SUCCESSFUL) {
       esc = sc;
       goto cleanup;
@@ -340,6 +355,10 @@ rtems_status_code rtems_bdpart_read(
 
 cleanup:
 
+  if (fd >= 0) {
+    close( fd);
+  }
+
   if (block != NULL) {
     rtems_bdbuf_release( block);
   }
diff --git a/cpukit/libblock/src/bdpart-register.c b/cpukit/libblock/src/bdpart-register.c
index 172c8b4964..d937e65e6c 100644
--- a/cpukit/libblock/src/bdpart-register.c
+++ b/cpukit/libblock/src/bdpart-register.c
@@ -47,12 +47,16 @@ rtems_status_code rtems_bdpart_register(
   char *logical_disk_marker = NULL;
   size_t disk_name_size = strlen( disk_name);
   size_t i = 0;
+  int fd = -1;
+  const rtems_disk_device *dd = NULL;
 
   /* Get disk data */
-  sc = rtems_bdpart_get_disk_data( disk_name, &disk, &disk_end);
+  sc = rtems_bdpart_get_disk_data( disk_name, &fd, &dd, &disk_end);
   if (sc != RTEMS_SUCCESSFUL) {
     return sc;
   }
+  disk = rtems_disk_get_device_identifier( dd);
+  close( fd);
 
   /* Get the disk device identifier */
   rtems_filesystem_split_dev_t( disk, major, minor);
@@ -134,12 +138,16 @@ rtems_status_code rtems_bdpart_unregister(
   dev_t disk = 0;
   dev_t logical_disk = 0;
   size_t i = 0;
+  int fd = -1;
+  const rtems_disk_device *dd = NULL;
 
   /* Get disk data */
-  sc = rtems_bdpart_get_disk_data( disk_name, &disk, &disk_end);
+  sc = rtems_bdpart_get_disk_data( disk_name, &fd, &dd, &disk_end);
   if (sc != RTEMS_SUCCESSFUL) {
     return sc;
   }
+  disk = rtems_disk_get_device_identifier( dd);
+  close( fd);
 
   /* Get the disk device identifier */
   rtems_filesystem_split_dev_t( disk, major, minor);
diff --git a/cpukit/libblock/src/bdpart-write.c b/cpukit/libblock/src/bdpart-write.c
index 92e80a24ec..9cccda5e5b 100644
--- a/cpukit/libblock/src/bdpart-write.c
+++ b/cpukit/libblock/src/bdpart-write.c
@@ -45,7 +45,7 @@ static void rtems_bdpart_write_mbr_partition(
 }
 
 static rtems_status_code rtems_bdpart_new_record(
-  dev_t disk,
+  const rtems_disk_device *dd,
   rtems_blkdev_bnum index,
   rtems_bdbuf_buffer **block
 )
@@ -61,7 +61,7 @@ static rtems_status_code rtems_bdpart_new_record(
   }
 
   /* Read the new record block (this accounts for disk block sizes > 512) */
-  sc = rtems_bdbuf_read( disk, index, block);
+  sc = rtems_bdbuf_read( dd, index, block);
   if (sc != RTEMS_SUCCESSFUL) {
     return sc;
   }
@@ -99,10 +99,11 @@ rtems_status_code rtems_bdpart_write(
   rtems_blkdev_bnum disk_end = 0;
   rtems_blkdev_bnum record_space =
     dos_compatibility ? RTEMS_BDPART_MBR_CYLINDER_SIZE : 1;
-  dev_t disk = 0;
   size_t ppc = 0; /* Primary partition count */
   size_t i = 0;
   uint8_t *data = NULL;
+  int fd = -1;
+  const rtems_disk_device *dd = NULL;
 
   /* Check if we have something to do */
   if (count == 0) {
@@ -116,7 +117,7 @@ rtems_status_code rtems_bdpart_write(
   }
 
   /* Get disk data */
-  sc = rtems_bdpart_get_disk_data( disk_name, &disk, &disk_end);
+  sc = rtems_bdpart_get_disk_data( disk_name, &fd, &dd, &disk_end);
   if (sc != RTEMS_SUCCESSFUL) {
     return sc;
   }
@@ -211,7 +212,7 @@ rtems_status_code rtems_bdpart_write(
   }
 
   /* New MBR */
-  sc = rtems_bdpart_new_record( disk, 0, &block);
+  sc = rtems_bdpart_new_record( dd, 0, &block);
   if (sc != RTEMS_SUCCESSFUL) {
     esc = sc;
     goto cleanup;
@@ -275,7 +276,7 @@ rtems_status_code rtems_bdpart_write(
 
       /* New EBR */
       ebr = p->begin - record_space;
-      sc = rtems_bdpart_new_record( disk, ebr, &block);
+      sc = rtems_bdpart_new_record( dd, ebr, &block);
       if (sc != RTEMS_SUCCESSFUL) {
         esc = sc;
         goto cleanup;
@@ -294,6 +295,10 @@ rtems_status_code rtems_bdpart_write(
 
 cleanup:
 
+  if (fd >= 0) {
+    close( fd);
+  }
+
   if (block != NULL) {
     rtems_bdbuf_sync( block);
   }
diff --git a/cpukit/libblock/src/blkdev.c b/cpukit/libblock/src/blkdev.c
index c986e69889..3e950d6a72 100644
--- a/cpukit/libblock/src/blkdev.c
+++ b/cpukit/libblock/src/blkdev.c
@@ -46,7 +46,6 @@ rtems_blkdev_generic_read(
     uint32_t count = args->count;
     rtems_blkdev_bnum block = (rtems_blkdev_bnum) (args->offset / block_size);
     uint32_t blkofs = (uint32_t) (args->offset % block_size);
-    dev_t dev = dd->dev;
 
     args->bytes_moved = 0;
 
@@ -55,7 +54,7 @@ rtems_blkdev_generic_read(
         rtems_bdbuf_buffer *diskbuf;
         uint32_t            copy;
 
-        rc = rtems_bdbuf_read(dev, block, &diskbuf);
+        rc = rtems_bdbuf_read(dd, block, &diskbuf);
         if (rc != RTEMS_SUCCESSFUL)
             break;
         copy = block_size - blkofs;
@@ -94,7 +93,6 @@ rtems_blkdev_generic_write(
     uint32_t count = args->count;
     rtems_blkdev_bnum block = (rtems_blkdev_bnum) (args->offset / block_size);
     uint32_t blkofs = (uint32_t) (args->offset % block_size);
-    dev_t dev = dd->dev;
 
     args->bytes_moved = 0;
 
@@ -104,9 +102,9 @@ rtems_blkdev_generic_write(
         uint32_t            copy;
 
         if ((blkofs == 0) && (count >= block_size))
-            rc = rtems_bdbuf_get(dev, block, &diskbuf);
+            rc = rtems_bdbuf_get(dd, block, &diskbuf);
         else
-            rc = rtems_bdbuf_read(dev, block, &diskbuf);
+            rc = rtems_bdbuf_read(dd, block, &diskbuf);
         if (rc != RTEMS_SUCCESSFUL)
             break;
 
@@ -207,7 +205,7 @@ rtems_blkdev_generic_ioctl(
             break;
 
         case RTEMS_BLKIO_SYNCDEV:
-            rc = rtems_bdbuf_syncdev(dd->dev);
+            rc = rtems_bdbuf_syncdev(dd);
             args->ioctl_return = (uint32_t) (rc == RTEMS_SUCCESSFUL ? 0 : -1);
             break;
 
diff --git a/cpukit/libblock/src/media.c b/cpukit/libblock/src/media.c
index b4ddd6ad7c..989f80ded2 100644
--- a/cpukit/libblock/src/media.c
+++ b/cpukit/libblock/src/media.c
@@ -812,15 +812,19 @@ static rtems_status_code disk_detach_worker(
 
   if (state == RTEMS_MEDIA_STATE_READY) {
     dev_t dev = 0;
+    rtems_disk_device *dd = NULL;
 
     sc = rtems_media_get_device_identifier(src, &dev);
     if (sc != RTEMS_SUCCESSFUL) {
       return RTEMS_IO_ERROR;
     }
 
-    sc = rtems_bdbuf_syncdev(dev);
-    if (sc != RTEMS_SUCCESSFUL) {
-      rsc = RTEMS_IO_ERROR;
+    dd = rtems_disk_obtain(dev);
+    if (dd != NULL) {
+      sc = rtems_bdbuf_syncdev(dd);
+      if (sc != RTEMS_SUCCESSFUL) {
+        rsc = RTEMS_IO_ERROR;
+      }
     }
 
     sc = rtems_disk_delete(dev);
@@ -828,7 +832,10 @@ static rtems_status_code disk_detach_worker(
       rsc = RTEMS_IO_ERROR;
     }
 
-    rtems_bdbuf_purge_dev(dev);
+    if (dd != NULL) {
+      rtems_bdbuf_purge_dev(dd);
+      rtems_disk_release(dd);
+    }
 
     if (rtems_filesystem_dev_minor_t(dev) == 0) {
       sc = rtems_io_unregister_driver(rtems_filesystem_dev_major_t(dev));
diff --git a/cpukit/libfs/src/dosfs/fat.c b/cpukit/libfs/src/dosfs/fat.c
index ba9ae23e86..39a7bacb24 100644
--- a/cpukit/libfs/src/dosfs/fat.c
+++ b/cpukit/libfs/src/dosfs/fat.c
@@ -37,9 +37,9 @@ fat_buf_access(fat_fs_info_t *fs_info, uint32_t   blk, int op_type,
     if (fs_info->c.state == FAT_CACHE_EMPTY)
     {
         if (op_type == FAT_OP_TYPE_READ)
-            sc = rtems_bdbuf_read(fs_info->vol.dev, blk, &fs_info->c.buf);
+            sc = rtems_bdbuf_read(fs_info->vol.dd, blk, &fs_info->c.buf);
         else
-            sc = rtems_bdbuf_get(fs_info->vol.dev, blk, &fs_info->c.buf);
+            sc = rtems_bdbuf_get(fs_info->vol.dd, blk, &fs_info->c.buf);
         if (sc != RTEMS_SUCCESSFUL)
             rtems_set_errno_and_return_minus_one(EIO);
         fs_info->c.blk_num = blk;
@@ -70,7 +70,7 @@ fat_buf_access(fat_fs_info_t *fs_info, uint32_t   blk, int op_type,
 
                 for (i = 1; i < fs_info->vol.fats; i++)
                 {
-                    sc = rtems_bdbuf_get(fs_info->vol.dev,
+                    sc = rtems_bdbuf_get(fs_info->vol.dd,
                                          fs_info->c.blk_num +
                                          fs_info->vol.fat_length * i,
                                          &b);
@@ -92,9 +92,9 @@ fat_buf_access(fat_fs_info_t *fs_info, uint32_t   blk, int op_type,
 
         }
         if (op_type == FAT_OP_TYPE_READ)
-            sc = rtems_bdbuf_read(fs_info->vol.dev, blk, &fs_info->c.buf);
+            sc = rtems_bdbuf_read(fs_info->vol.dd, blk, &fs_info->c.buf);
         else
-            sc = rtems_bdbuf_get(fs_info->vol.dev, blk, &fs_info->c.buf);
+            sc = rtems_bdbuf_get(fs_info->vol.dd, blk, &fs_info->c.buf);
         if (sc != RTEMS_SUCCESSFUL)
             rtems_set_errno_and_return_minus_one(EIO);
         fs_info->c.blk_num = blk;
@@ -133,7 +133,7 @@ fat_buf_release(fat_fs_info_t *fs_info)
 
             for (i = 1; i < fs_info->vol.fats; i++)
             {
-                sc = rtems_bdbuf_get(fs_info->vol.dev,
+                sc = rtems_bdbuf_get(fs_info->vol.dd,
                                      fs_info->c.blk_num +
                                      fs_info->vol.fat_length * i,
                                      &b);
@@ -362,27 +362,39 @@ fat_init_volume_info(rtems_filesystem_mount_table_entry_t *mt_entry)
     int                 i = 0;
     rtems_bdbuf_buffer *block = NULL;
 
-    rc = stat(mt_entry->dev, &stat_buf);
-    if (rc == -1)
-        return rc;
+    vol->fd = open(mt_entry->dev, O_RDWR);
+    if (vol->fd < 0)
+    {
+        rtems_set_errno_and_return_minus_one(ENXIO);
+    }
+
+    rc = fstat(vol->fd, &stat_buf);
+    if (rc != 0)
+    {
+        close(vol->fd);
+        rtems_set_errno_and_return_minus_one(ENXIO);
+    }
 
     /* Must be a block device. */
     if (!S_ISBLK(stat_buf.st_mode))
-        rtems_set_errno_and_return_minus_one(ENOTTY);
+    {
+        close(vol->fd);
+        rtems_set_errno_and_return_minus_one(ENXIO);
+    }
 
     /* check that device is registred as block device and lock it */
-    vol->dd = rtems_disk_obtain(stat_buf.st_rdev);
-    if (vol->dd == NULL)
-        rtems_set_errno_and_return_minus_one(EIO);
-
-    vol->dev = stat_buf.st_rdev;
+    rc = rtems_disk_fd_get_disk_device(vol->fd, &vol->dd);
+    if (rc != 0) {
+        close(vol->fd);
+        rtems_set_errno_and_return_minus_one(ENXIO);
+    }
 
     /* Read boot record */
     /* FIXME: Asserts FAT_MAX_BPB_SIZE < bdbuf block size */
-    sc = rtems_bdbuf_read( vol->dev, 0, &block);
+    sc = rtems_bdbuf_read( vol->dd, 0, &block);
     if (sc != RTEMS_SUCCESSFUL)
     {
-        rtems_disk_release(vol->dd);
+        close(vol->fd);
         rtems_set_errno_and_return_minus_one( EIO);
     }
 
@@ -391,7 +403,7 @@ fat_init_volume_info(rtems_filesystem_mount_table_entry_t *mt_entry)
     sc = rtems_bdbuf_release( block);
     if (sc != RTEMS_SUCCESSFUL)
     {
-        rtems_disk_release(vol->dd);
+        close(vol->fd);
         rtems_set_errno_and_return_minus_one( EIO );
     }
 
@@ -403,7 +415,7 @@ fat_init_volume_info(rtems_filesystem_mount_table_entry_t *mt_entry)
          (vol->bps != 2048) &&
          (vol->bps != 4096))
     {
-        rtems_disk_release(vol->dd);
+        close(vol->fd);
         rtems_set_errno_and_return_minus_one( EINVAL );
     }
 
@@ -419,7 +431,7 @@ fat_init_volume_info(rtems_filesystem_mount_table_entry_t *mt_entry)
      */
     if (vol->spc == 0)
     {
-        rtems_disk_release(vol->dd);
+        close(vol->fd);
         rtems_set_errno_and_return_minus_one(EINVAL);
     }
 
@@ -431,7 +443,7 @@ fat_init_volume_info(rtems_filesystem_mount_table_entry_t *mt_entry)
      */
     if ((vol->bpc = vol->bps << vol->spc_log2) > MS_BYTES_PER_CLUSTER_LIMIT)
     {
-        rtems_disk_release(vol->dd);
+        close(vol->fd);
         rtems_set_errno_and_return_minus_one(EINVAL);
     }
 
@@ -505,7 +517,7 @@ fat_init_volume_info(rtems_filesystem_mount_table_entry_t *mt_entry)
         vol->info_sec = FAT_GET_BR_FAT32_FS_INFO_SECTOR(boot_rec);
         if( vol->info_sec == 0 )
         {
-            rtems_disk_release(vol->dd);
+            close(vol->fd);
             rtems_set_errno_and_return_minus_one( EINVAL );
         }
         else
@@ -514,7 +526,7 @@ fat_init_volume_info(rtems_filesystem_mount_table_entry_t *mt_entry)
                                   FAT_FSI_LEADSIG_SIZE, fs_info_sector);
             if ( ret < 0 )
             {
-                rtems_disk_release(vol->dd);
+                close(vol->fd);
                 return -1;
             }
 
@@ -522,7 +534,7 @@ fat_init_volume_info(rtems_filesystem_mount_table_entry_t *mt_entry)
                 FAT_FSINFO_LEAD_SIGNATURE_VALUE)
             {
                 _fat_block_release(mt_entry);
-                rtems_disk_release(vol->dd);
+                close(vol->fd);
                 rtems_set_errno_and_return_minus_one( EINVAL );
             }
             else
@@ -532,7 +544,7 @@ fat_init_volume_info(rtems_filesystem_mount_table_entry_t *mt_entry)
                 if ( ret < 0 )
                 {
                     _fat_block_release(mt_entry);
-                    rtems_disk_release(vol->dd);
+                    close(vol->fd);
                     return -1;
                 }
 
@@ -543,7 +555,7 @@ fat_init_volume_info(rtems_filesystem_mount_table_entry_t *mt_entry)
                 if ( rc != RC_OK )
                 {
                     _fat_block_release(mt_entry);
-                    rtems_disk_release(vol->dd);
+                    close(vol->fd);
                     return rc;
                 }
             }
@@ -566,7 +578,7 @@ fat_init_volume_info(rtems_filesystem_mount_table_entry_t *mt_entry)
     fs_info->vhash = calloc(FAT_HASH_SIZE, sizeof(rtems_chain_control));
     if ( fs_info->vhash == NULL )
     {
-        rtems_disk_release(vol->dd);
+        close(vol->fd);
         rtems_set_errno_and_return_minus_one( ENOMEM );
     }
 
@@ -576,7 +588,7 @@ fat_init_volume_info(rtems_filesystem_mount_table_entry_t *mt_entry)
     fs_info->rhash = calloc(FAT_HASH_SIZE, sizeof(rtems_chain_control));
     if ( fs_info->rhash == NULL )
     {
-        rtems_disk_release(vol->dd);
+        close(vol->fd);
         free(fs_info->vhash);
         rtems_set_errno_and_return_minus_one( ENOMEM );
     }
@@ -589,7 +601,7 @@ fat_init_volume_info(rtems_filesystem_mount_table_entry_t *mt_entry)
     fs_info->uino = (char *)calloc(fs_info->uino_pool_size, sizeof(char));
     if ( fs_info->uino == NULL )
     {
-        rtems_disk_release(vol->dd);
+        close(vol->fd);
         free(fs_info->vhash);
         free(fs_info->rhash);
         rtems_set_errno_and_return_minus_one( ENOMEM );
@@ -597,7 +609,7 @@ fat_init_volume_info(rtems_filesystem_mount_table_entry_t *mt_entry)
     fs_info->sec_buf = (uint8_t *)calloc(vol->bps, sizeof(uint8_t));
     if (fs_info->sec_buf == NULL)
     {
-        rtems_disk_release(vol->dd);
+        close(vol->fd);
         free(fs_info->vhash);
         free(fs_info->rhash);
         free(fs_info->uino);
@@ -634,7 +646,7 @@ fat_shutdown_drive(rtems_filesystem_mount_table_entry_t *mt_entry)
 
     fat_buf_release(fs_info);
 
-    if (rtems_bdbuf_syncdev(fs_info->vol.dev) != RTEMS_SUCCESSFUL)
+    if (rtems_bdbuf_syncdev(fs_info->vol.dd) != RTEMS_SUCCESSFUL)
         rc = -1;
 
     for (i = 0; i < FAT_HASH_SIZE; i++)
@@ -660,7 +672,7 @@ fat_shutdown_drive(rtems_filesystem_mount_table_entry_t *mt_entry)
 
     free(fs_info->uino);
     free(fs_info->sec_buf);
-    rtems_disk_release(fs_info->vol.dd);
+    close(fs_info->vol.fd);
 
     if (rc)
         errno = EIO;
diff --git a/cpukit/libfs/src/dosfs/fat.h b/cpukit/libfs/src/dosfs/fat.h
index 8d62662c10..204095cae2 100644
--- a/cpukit/libfs/src/dosfs/fat.h
+++ b/cpukit/libfs/src/dosfs/fat.h
@@ -319,7 +319,7 @@ typedef struct fat_vol_s
     uint8_t            mirror;         /* mirroring enabla/disable */
     uint32_t           afat_loc;       /* active FAT location */
     uint8_t            afat;           /* the number of active FAT */
-    dev_t              dev;            /* device ID */
+    int                fd;             /* the disk device file descriptor */
     rtems_disk_device *dd;             /* disk device (see libblock) */
     void              *private_data;   /* reserved */
 } fat_vol_t;
diff --git a/cpukit/libfs/src/dosfs/fat_file.c b/cpukit/libfs/src/dosfs/fat_file.c
index 5375e90336..01dabc8f80 100644
--- a/cpukit/libfs/src/dosfs/fat_file.c
+++ b/cpukit/libfs/src/dosfs/fat_file.c
@@ -795,7 +795,7 @@ fat_file_datasync(
         for ( i = 0; i < fs_info->vol.spc; i++ )
         {
             /* ... sync it */
-            sc = rtems_bdbuf_read(fs_info->vol.dev, (sec + i), &block);
+            sc = rtems_bdbuf_read(fs_info->vol.dd, (sec + i), &block);
             if (sc != RTEMS_SUCCESSFUL)
                 rtems_set_errno_and_return_minus_one( EIO );
 
diff --git a/cpukit/libfs/src/dosfs/msdos_dir.c b/cpukit/libfs/src/dosfs/msdos_dir.c
index 725fd254d0..67a0bdaaa9 100644
--- a/cpukit/libfs/src/dosfs/msdos_dir.c
+++ b/cpukit/libfs/src/dosfs/msdos_dir.c
@@ -532,7 +532,7 @@ msdos_dir_stat(
     if (sc != RTEMS_SUCCESSFUL)
         rtems_set_errno_and_return_minus_one(EIO);
 
-    buf->st_dev = fs_info->fat.vol.dev;
+    buf->st_dev = rtems_disk_get_device_identifier(fs_info->fat.vol.dd);
     buf->st_ino = fat_fd->ino;
     buf->st_mode  = S_IFDIR | S_IRWXU | S_IRWXG | S_IRWXO;
     buf->st_rdev = 0ll;
diff --git a/cpukit/libfs/src/dosfs/msdos_file.c b/cpukit/libfs/src/dosfs/msdos_file.c
index b2f98b890d..7cd55b0494 100644
--- a/cpukit/libfs/src/dosfs/msdos_file.c
+++ b/cpukit/libfs/src/dosfs/msdos_file.c
@@ -281,7 +281,7 @@ msdos_file_stat(
     if (sc != RTEMS_SUCCESSFUL)
         rtems_set_errno_and_return_minus_one(EIO);
 
-    buf->st_dev = fs_info->fat.vol.dev;
+    buf->st_dev = rtems_disk_get_device_identifier(fs_info->fat.vol.dd);
     buf->st_ino = fat_fd->ino;
     buf->st_mode  = S_IFREG | S_IRWXU | S_IRWXG | S_IRWXO;
     buf->st_rdev = 0ll;
diff --git a/cpukit/libfs/src/dosfs/msdos_format.c b/cpukit/libfs/src/dosfs/msdos_format.c
index 1394f811c4..2a9d09048f 100644
--- a/cpukit/libfs/src/dosfs/msdos_format.c
+++ b/cpukit/libfs/src/dosfs/msdos_format.c
@@ -370,7 +370,7 @@ static int msdos_format_determine_fmt_params
 +---------------------------------------------------------------------------+
 | Input Parameters:                                                         |
 \*-------------------------------------------------------------------------*/
- const rtems_disk_device            *dd,       /* disk device structure          */
+ int fd,                                       /* disk file descriptor */
  const msdos_format_request_param_t *rqdata,   /* requested fmt parameters */
  msdos_format_param_t               *fmt_params/* computed fmt parameters        */
  )
@@ -386,18 +386,24 @@ static int msdos_format_determine_fmt_params
   uint64_t total_size = 0;
 
   memset(fmt_params,0,sizeof(*fmt_params));
+
   /*
    * this one is fixed in this implementation.
    * At least one thing we don't have to magically guess...
    */
   if (ret_val == 0) {
-    fmt_params->bytes_per_sector = dd->block_size;
-    fmt_params->totl_sector_cnt  = dd->size;
-    total_size = dd->block_size * dd->size;
+    ret_val = rtems_disk_fd_get_block_size(fd, &fmt_params->bytes_per_sector);
+  }
+  if (ret_val == 0) {
+    ret_val = rtems_disk_fd_get_block_count(fd, &fmt_params->totl_sector_cnt);
+  }
+  if (ret_val == 0) {
+    total_size = fmt_params->bytes_per_sector * fmt_params->totl_sector_cnt;
     msdos_format_printf (rqdata, MSDOS_FMT_INFO_LEVEL_DETAIL,
                          "bytes per sector: %d\ntotal sectors: %d\ntotal size: %lu\n",
-                         dd->block_size, dd->size, total_size);
+                         fmt_params->bytes_per_sector, fmt_params->totl_sector_cnt, total_size);
   }
+
   /*
    * determine number of FATs
    */
@@ -889,7 +895,6 @@ int msdos_format
 {
   char                 tmp_sec[FAT_TOTAL_MBR_SIZE];
   int                  rc;
-  rtems_disk_device   *dd        = NULL;
   struct stat          stat_buf;
   int                  ret_val   = 0;
   int                  fd        = -1;
@@ -923,20 +928,11 @@ int msdos_format
     ret_val = -1;
   }
 
-  /* check that  device is registered as block device and lock it */
-  if (ret_val == 0) {
-    dd = rtems_disk_obtain(stat_buf.st_rdev);
-    if (dd == NULL) {
-      errno = ENOTTY;
-      ret_val = -1;
-    }
-  }
-
   /*
    * compute formatting parameters
    */
   if (ret_val == 0) {
-    ret_val = msdos_format_determine_fmt_params(dd,rqdata,&fmt_params);
+    ret_val = msdos_format_determine_fmt_params(fd,rqdata,&fmt_params);
   }
   /*
    * if requested, write whole disk/partition with 0xe5
@@ -1120,8 +1116,6 @@ int msdos_format
   if (fd != -1) {
     close(fd);
   }
-  if (dd != NULL) {
-    rtems_disk_release(dd);
-  }
+
   return ret_val;
 }
diff --git a/cpukit/libfs/src/rfs/rtems-rfs-buffer.c b/cpukit/libfs/src/rfs/rtems-rfs-buffer.c
index ea5cbb3fb3..60f9deae32 100644
--- a/cpukit/libfs/src/rfs/rtems-rfs-buffer.c
+++ b/cpukit/libfs/src/rfs/rtems-rfs-buffer.c
@@ -20,8 +20,10 @@
 #include "config.h"
 #endif
 
+#include <sys/stat.h>
 #include <inttypes.h>
 #include <errno.h>
+#include <fcntl.h>
 
 #include <rtems/rfs/rtems-rfs-buffer.h>
 #include <rtems/rfs/rtems-rfs-file-system.h>
@@ -285,16 +287,27 @@ int
 rtems_rfs_buffer_open (const char* name, rtems_rfs_file_system* fs)
 {
   struct stat st;
+#if RTEMS_RFS_USE_LIBBLOCK
+  int rv;
+#endif
 
   if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_SYNC))
     printf ("rtems-rfs: buffer-open: opening: %s\n", name);
 
-  if (stat (name, &st) < 0)
+  fs->device = open (name, O_RDWR);
+  if (fs->device < 0)
+  {
+    if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_OPEN))
+      printf ("rtems-rfs: buffer-open: cannot open file\n");
+    return ENXIO;
+  }
+
+  if (fstat (fs->device, &st) < 0)
   {
     if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_OPEN))
       printf ("rtems-rfs: buffer-open: stat '%s' failed: %s\n",
               name, strerror (errno));
-    return ENOENT;
+    return ENXIO;
   }
 
 #if RTEMS_RFS_USE_LIBBLOCK
@@ -305,26 +318,20 @@ rtems_rfs_buffer_open (const char* name, rtems_rfs_file_system* fs)
   {
     if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_OPEN))
       printf ("rtems-rfs: buffer-open: '%s' is not a block device\n", name);
-    return EIO;
+    return ENXIO;
   }
 
   /*
    * Check that device is registred as a block device and lock it.
    */
-  fs->disk = rtems_disk_obtain (st.st_rdev);
-  if (!fs->disk)
+  rv = rtems_disk_fd_get_disk_device (fs->device, &fs->disk);
+  if (rv != 0)
   {
     if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_OPEN))
       printf ("rtems-rfs: buffer-open: cannot obtain the disk\n");
-    return EIO;
+    return ENXIO;
   }
 #else
-  fs->device = open (name, O_RDWR);
-  if (fs->device < 0)
-  {
-    if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_OPEN))
-      printf ("rtems-rfs: buffer-open: cannot open file\n");
-  }
   fs->media_size = st.st_size;
   strcat (fs->name, name);
 #endif
@@ -355,9 +362,6 @@ rtems_rfs_buffer_close (rtems_rfs_file_system* fs)
     printf ("rtems-rfs: buffer-close: set media block size failed: %d: %s\n",
             rc, strerror (rc));
 
-#if RTEMS_RFS_USE_LIBBLOCK
-  rtems_disk_release (fs->disk);
-#else
   if (close (fs->device) < 0)
   {
     rc = errno;
@@ -365,7 +369,6 @@ rtems_rfs_buffer_close (rtems_rfs_file_system* fs)
       printf ("rtems-rfs: buffer-close: file close failed: %d: %s\n",
               rc, strerror (rc));
   }
-#endif
 
   return rc;
 }
diff --git a/cpukit/libfs/src/rfs/rtems-rfs-file-system.h b/cpukit/libfs/src/rfs/rtems-rfs-file-system.h
index 0ceade228e..96fdf6c9ab 100644
--- a/cpukit/libfs/src/rfs/rtems-rfs-file-system.h
+++ b/cpukit/libfs/src/rfs/rtems-rfs-file-system.h
@@ -131,6 +131,11 @@ struct _rtems_rfs_file_system
    */
   size_t block_size;
 
+  /**
+   * The file descriptor for device I/O.
+   */
+  int device;
+
 #if RTEMS_RFS_USE_LIBBLOCK
   /**
    * The disk device. This is the data about the block device this file system
@@ -140,11 +145,6 @@ struct _rtems_rfs_file_system
   rtems_disk_device* disk;
 #else
   /**
-   * The device number which is a the file handle for device I/O.
-   */
-  dev_t device;
-
-  /**
    * The number of blocks in the file system.
    */
   size_t size;
@@ -284,7 +284,7 @@ struct _rtems_rfs_file_system
  * @param _fs Pointer to the file system.
  */
 #if RTEMS_RFS_USE_LIBBLOCK
-#define rtems_rfs_fs_device(_fs) ((_fs)->disk->dev)
+#define rtems_rfs_fs_device(_fs) ((_fs)->disk)
 #else
 #define rtems_rfs_fs_device(_fs) ((_fs)->device)
 #endif