/**
* @file
*
* @brief RTEMS File Systems Buffer Routines
* @ingroup rtems_rfs
*/
/*
* COPYRIGHT (c) 2010 Chris Johns <chrisj@rtems.org>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <sys/stat.h>
#include <inttypes.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <rtems/rfs/rtems-rfs-buffer.h>
#include <rtems/rfs/rtems-rfs-file-system.h>
/**
* Scan the chain for a buffer that matches the block number.
*
* @param chain The chain to scan.
* @param count The number of items on the chain.
* @param block The block number to find.
* @return rtems_rfs_buffer* The buffer if found else NULL.
*/
static rtems_rfs_buffer*
rtems_rfs_scan_chain (rtems_chain_control* chain,
uint32_t* count,
rtems_rfs_buffer_block block)
{
rtems_rfs_buffer* buffer;
rtems_chain_node* node;
node = rtems_chain_last (chain);
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_CHAINS))
printf ("rtems-rfs: buffer-scan: count=%" PRIu32 ", block=%" PRIu32 ": ", *count, block);
while (!rtems_chain_is_head (chain, node))
{
buffer = (rtems_rfs_buffer*) node;
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_CHAINS))
printf ("%" PRIuPTR " ", ((intptr_t) buffer->user));
if (((rtems_rfs_buffer_block) ((intptr_t)(buffer->user))) == block)
{
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_CHAINS))
printf (": found block=%" PRIuPTR "\n",
((intptr_t)(buffer->user)));
(*count)--;
rtems_chain_extract_unprotected (node);
rtems_chain_set_off_chain (node);
return buffer;
}
node = rtems_chain_previous (node);
}
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_CHAINS))
printf (": not found\n");
return NULL;
}
int
rtems_rfs_buffer_handle_request (rtems_rfs_file_system* fs,
rtems_rfs_buffer_handle* handle,
rtems_rfs_buffer_block block,
bool read)
{
int rc;
/*
* If the handle has a buffer release it. This allows a handle to be reused
* without needing to close then open it again.
*/
if (rtems_rfs_buffer_handle_has_block (handle))
{
/*
* Treat block 0 as special to handle the loading of the super block.
*/
if (block && (rtems_rfs_buffer_bnum (handle) == block))
return 0;
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_HANDLE_REQUEST))
printf ("rtems-rfs: buffer-request: handle has buffer: %" PRIu32 "\n",
rtems_rfs_buffer_bnum (handle));
rc = rtems_rfs_buffer_handle_release (fs, handle);
if (rc > 0)
return rc;
handle->dirty = false;
handle->bnum = 0;
}
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_HANDLE_REQUEST))
printf ("rtems-rfs: buffer-request: block=%" PRIu32 "\n", block);
/*
* First check to see if the buffer has already been requested and is
* currently attached to a handle. If it is share the access. A buffer could
* be shared where different parts of the block have separate functions. An
* example is an inode block and the file system needs to handle 2 inodes in
* the same block at the same time.
*/
if (fs->buffers_count)
{
/*
* Check the active buffer list for shared buffers.
*/
handle->buffer = rtems_rfs_scan_chain (&fs->buffers,
&fs->buffers_count,
block);
if (rtems_rfs_buffer_handle_has_block (handle) &&
rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_HANDLE_REQUEST))
printf ("rtems-rfs: buffer-request: buffer shared: refs: %d\n",
rtems_rfs_buffer_refs (handle) + 1);
}
/*
* If the buffer has not been found check the local cache of released
* buffers. There are release and released modified lists to preserve the
* state.
*/
if (!rtems_rfs_fs_no_local_cache (fs) &&
!rtems_rfs_buffer_handle_has_block (handle))
{
/*
* Check the local cache of released buffers.
*/
if (fs->release_count)
handle->buffer = rtems_rfs_scan_chain (&fs->release,
&fs->release_count,
block);
if (!rtems_rfs_buffer_handle_has_block (handle) &&
fs->release_modified_count)
{
handle->buffer = rtems_rfs_scan_chain (&fs->release_modified,
&fs->release_modified_count,
block);
/*
* If we found a buffer retain the dirty buffer state.
*/
if (rtems_rfs_buffer_handle_has_block (handle))
rtems_rfs_buffer_mark_dirty (handle);
}
}
/*
* If not located we request the buffer from the I/O layer.
*/
if (!rtems_rfs_buffer_handle_has_block (handle))
{
rc = rtems_rfs_buffer_io_request (fs, block, read, &handle->buffer);
if (rc > 0)
{
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_HANDLE_REQUEST))
printf ("rtems-rfs: buffer-request: block=%" PRIu32 ": bdbuf-%s: %d: %s\n",
block, read ? "read" : "get", rc, strerror (rc));
return rc;
}
rtems_chain_set_off_chain (rtems_rfs_buffer_link(handle));
}
/*
* Increase the reference count of the buffer.
*/
rtems_rfs_buffer_refs_up (handle);
rtems_chain_append_unprotected (&fs->buffers,
rtems_rfs_buffer_link (handle));
fs->buffers_count++;
handle->buffer->user = (void*) ((intptr_t) block);
handle->bnum = block;
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_HANDLE_REQUEST))
printf ("rtems-rfs: buffer-request: block=%" PRIu32 " bdbuf-%s=%" PRIu32 " refs=%d\n",
block, read ? "read" : "get", handle->buffer->block,
handle->buffer->references);
return 0;
}
int
rtems_rfs_buffer_handle_release (rtems_rfs_file_system* fs,
rtems_rfs_buffer_handle* handle)
{
int rc = 0;
if (rtems_rfs_buffer_handle_has_block (handle))
{
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_HANDLE_RELEASE))
printf ("rtems-rfs: buffer-release: block=%" PRIu32 " %s refs=%d %s\n",
rtems_rfs_buffer_bnum (handle),
rtems_rfs_buffer_dirty (handle) ? "(dirty)" : "",
rtems_rfs_buffer_refs (handle),
rtems_rfs_buffer_refs (handle) == 0 ? "BAD REF COUNT" : "");
if (rtems_rfs_buffer_refs (handle) > 0)
rtems_rfs_buffer_refs_down (handle);
if (rtems_rfs_buffer_refs (handle) == 0)
{
rtems_chain_extract_unprotected (rtems_rfs_buffer_link (handle));
fs->buffers_count--;
if (rtems_rfs_fs_no_local_cache (fs))
{
handle->buffer->user = (void*) 0;
rc = rtems_rfs_buffer_io_release (handle->buffer,
rtems_rfs_buffer_dirty (handle));
}
else
{
/*
* If the total number of held buffers is higher than the configured
* value remove a buffer from the queue with the most buffers and
* release. The buffers are held on the queues with the newest at the
* head.
*
* This code stops a large series of transactions causing all the
* buffers in the cache being held in queues of this file system.
*/
if ((fs->release_count +
fs->release_modified_count) >= fs->max_held_buffers)
{
rtems_rfs_buffer* buffer;
bool modified;
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_HANDLE_RELEASE))
printf ("rtems-rfs: buffer-release: local cache overflow:"
" %" PRIu32 "\n", fs->release_count + fs->release_modified_count);
if (fs->release_count > fs->release_modified_count)
{
buffer = (rtems_rfs_buffer*)
rtems_chain_get_unprotected (&fs->release);
fs->release_count--;
modified = false;
}
else
{
buffer = (rtems_rfs_buffer*)
rtems_chain_get_unprotected (&fs->release_modified);
fs->release_modified_count--;
modified = true;
}
buffer->user = (void*) 0;
rc = rtems_rfs_buffer_io_release (buffer, modified);
}
if (rtems_rfs_buffer_dirty (handle))
{
rtems_chain_append_unprotected (&fs->release_modified,
rtems_rfs_buffer_link (handle));
fs->release_modified_count++;
}
else
{
rtems_chain_append_unprotected (&fs->release,
rtems_rfs_buffer_link (handle));
fs->release_count++;
}
}
}
handle->buffer = NULL;
}
return rc;
}
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);
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 ENXIO;
}
#if RTEMS_RFS_USE_LIBBLOCK
/*
* Is the device a block device ?
*/
if (!S_ISBLK (st.st_mode))
{
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_OPEN))
printf ("rtems-rfs: buffer-open: '%s' is not a block device\n", name);
return ENXIO;
}
/*
* Check that device is registred as a block device and lock it.
*/
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 ENXIO;
}
#else
fs->media_size = st.st_size;
strcat (fs->name, name);
#endif
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_SYNC))
printf ("rtems-rfs: buffer-open: blks=%" PRId32 ", blk-size=%" PRId32 "\n",
rtems_rfs_fs_media_blocks (fs),
rtems_rfs_fs_media_block_size (fs));
return 0;
}
int
rtems_rfs_buffer_close (rtems_rfs_file_system* fs)
{
int rc = 0;
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_CLOSE))
printf ("rtems-rfs: buffer-close: closing\n");
/*
* Change the block size to the media device size. It will release and sync
* all buffers.
*/
rc = rtems_rfs_buffer_setblksize (fs, rtems_rfs_fs_media_block_size (fs));
if ((rc > 0) && rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_CLOSE))
printf ("rtems-rfs: buffer-close: set media block size failed: %d: %s\n",
rc, strerror (rc));
if (close (fs->device) < 0)
{
rc = errno;
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_CLOSE))
printf ("rtems-rfs: buffer-close: file close failed: %d: %s\n",
rc, strerror (rc));
}
return rc;
}
int
rtems_rfs_buffer_sync (rtems_rfs_file_system* fs)
{
int result = 0;
#if RTEMS_RFS_USE_LIBBLOCK
rtems_status_code sc;
#endif
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_SYNC))
printf ("rtems-rfs: buffer-sync: syncing\n");
/*
* @todo Split in the separate files for each type.
*/
#if RTEMS_RFS_USE_LIBBLOCK
sc = rtems_bdbuf_syncdev (rtems_rfs_fs_device (fs));
if (sc != RTEMS_SUCCESSFUL)
{
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_SYNC))
printf ("rtems-rfs: buffer-sync: device sync failed: %s\n",
rtems_status_text (sc));
result = EIO;
}
rtems_disk_release (fs->disk);
#else
if (fsync (fs->device) < 0)
{
result = errno;
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_CLOSE))
printf ("rtems-rfs: buffer-sync: file sync failed: %d: %s\n",
result, strerror (result));
}
#endif
return result;
}
int
rtems_rfs_buffer_setblksize (rtems_rfs_file_system* fs, size_t size)
{
int rc;
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_SETBLKSIZE))
printf ("rtems-rfs: buffer-setblksize: block size: %zu\n", size);
rc = rtems_rfs_buffers_release (fs);
if ((rc > 0) && rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_SETBLKSIZE))
printf ("rtems-rfs: buffer-setblksize: buffer release failed: %d: %s\n",
rc, strerror (rc));
rc = rtems_rfs_buffer_sync (fs);
if ((rc > 0) && rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_SETBLKSIZE))
printf ("rtems-rfs: buffer-setblksize: device sync failed: %d: %s\n",
rc, strerror (rc));
#if RTEMS_RFS_USE_LIBBLOCK
rc = fs->disk->ioctl (fs->disk, RTEMS_BLKIO_SETBLKSIZE, &size);
if (rc < 0)
rc = errno;
#endif
return rc;
}
static int
rtems_rfs_release_chain (rtems_chain_control* chain,
uint32_t* count,
bool modified)
{
rtems_rfs_buffer* buffer;
int rrc = 0;
int rc;
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_CHAINS))
printf ("rtems-rfs: release-chain: count=%" PRIu32 "\n", *count);
while (!rtems_chain_is_empty (chain))
{
buffer = (rtems_rfs_buffer*) rtems_chain_get_unprotected (chain);
(*count)--;
buffer->user = (void*) 0;
rc = rtems_rfs_buffer_io_release (buffer, modified);
if ((rc > 0) && (rrc == 0))
rrc = rc;
}
return rrc;
}
int
rtems_rfs_buffers_release (rtems_rfs_file_system* fs)
{
int rrc = 0;
int rc;
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_RELEASE))
printf ("rtems-rfs: buffers-release: active:%" PRIu32 " "
"release:%" PRIu32 " release-modified:%" PRIu32 "\n",
fs->buffers_count, fs->release_count, fs->release_modified_count);
rc = rtems_rfs_release_chain (&fs->release,
&fs->release_count,
false);
if ((rc > 0) && (rrc == 0))
rrc = rc;
rc = rtems_rfs_release_chain (&fs->release_modified,
&fs->release_modified_count,
true);
if ((rc > 0) && (rrc == 0))
rrc = rc;
return rrc;
}