int
rtems_rfs_file_io_release (rtems_rfs_file_handle* handle)
{
int rc = 0;
if (rtems_rfs_buffer_handle_has_block (&handle->buffer))
rc = rtems_rfs_buffer_handle_release (rtems_rfs_file_fs (handle),
rtems_rfs_file_buffer (handle));
return rc;
}
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 (&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 (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 (&fs->release);
fs->release_count--;
modified = false;
}
else
{
buffer =
(rtems_rfs_buffer*) rtems_chain_get (&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 (&fs->release_modified,
rtems_rfs_buffer_link (handle));
fs->release_modified_count++;
}
else
{
rtems_chain_append (&fs->release, rtems_rfs_buffer_link (handle));
fs->release_count++;
}
}
}
handle->buffer = NULL;
}
return rc;
}
int
rtems_rfs_file_seek (rtems_rfs_file_handle* handle,
rtems_rfs_pos pos,
rtems_rfs_pos* new_pos)
{
if (rtems_rfs_trace (RTEMS_RFS_TRACE_FILE_IO))
printf ("rtems-rfs: file-seek: new=%" PRIu64 "\n", pos);
/*
* This call only sets the position if it is in a valid part of the file. The
* user can request past the end of the file then write to extend the
* file. The lseek entry states:
*
* "Although lseek() may position the file offset beyond the end of the
* file, this function does not itself extend the size of the file."
*
* This means the file needs to set the file size to the pos only when a
* write occurs.
*/
if (pos < rtems_rfs_file_shared_get_size (rtems_rfs_file_fs (handle),
handle->shared))
{
rtems_rfs_file_set_bpos (handle, pos);
/*
* If the file has a block check if it maps to the current position and it
* does not release it. That will force us to get the block at the new
* position when the I/O starts.
*/
if (rtems_rfs_buffer_handle_has_block (&handle->buffer))
{
rtems_rfs_buffer_block block;
int rc;
rc = rtems_rfs_block_map_find (rtems_rfs_file_fs (handle),
rtems_rfs_file_map (handle),
rtems_rfs_file_bpos (handle),
&block);
if (rc > 0)
return rc;
if (rtems_rfs_buffer_bnum (&handle->buffer) != block)
{
rc = rtems_rfs_buffer_handle_release (rtems_rfs_file_fs (handle),
rtems_rfs_file_buffer (handle));
if (rc > 0)
return rc;
}
}
}
else
{
/*
* The seek is outside the current file so release any buffer. A write will
* extend the file.
*/
int rc = rtems_rfs_file_io_release (handle);
if (rc > 0)
return rc;
}
*new_pos = pos;
return 0;
}
int
rtems_rfs_file_io_end (rtems_rfs_file_handle* handle,
size_t size,
bool read)
{
bool atime;
bool mtime;
bool length;
int rc = 0;
if (rtems_rfs_trace (RTEMS_RFS_TRACE_FILE_IO))
printf ("rtems-rfs: file-io: end: %s size=%zu\n",
read ? "read" : "write", size);
if (rtems_rfs_buffer_handle_has_block (&handle->buffer))
{
if (!read)
rtems_rfs_buffer_mark_dirty (rtems_rfs_file_buffer (handle));
rc = rtems_rfs_buffer_handle_release (rtems_rfs_file_fs (handle),
rtems_rfs_file_buffer (handle));
if (rc > 0)
{
printf (
"rtems-rfs: file-io: end: error on release: %s size=%zu: %d: %s\n",
read ? "read" : "write", size, rc, strerror (rc));
return rc;
}
}
/*
* Update the handle's position. Only a block size can be handled at a time
* so no special maths is needed. If the offset is bigger than the block size
* increase the block number and adjust the offset.
*
* If we are the last block and the position is past the current size update
* the size with the new length. The map holds the block count.
*/
handle->bpos.boff += size;
if (handle->bpos.boff >=
rtems_rfs_fs_block_size (rtems_rfs_file_fs (handle)))
{
handle->bpos.bno++;
handle->bpos.boff -= rtems_rfs_fs_block_size (rtems_rfs_file_fs (handle));
}
length = false;
mtime = false;
if (!read &&
rtems_rfs_block_map_past_end (rtems_rfs_file_map (handle),
rtems_rfs_file_bpos (handle)))
{
rtems_rfs_block_map_set_size_offset (rtems_rfs_file_map (handle),
handle->bpos.boff);
length = true;
mtime = true;
}
atime = rtems_rfs_file_update_atime (handle);
mtime = rtems_rfs_file_update_mtime (handle) && mtime;
length = rtems_rfs_file_update_length (handle) && length;
if (rtems_rfs_trace (RTEMS_RFS_TRACE_FILE_IO))
printf ("rtems-rfs: file-io: end: pos=%" PRIu32 ":%" PRIu32 " %c %c %c\n",
handle->bpos.bno, handle->bpos.boff,
atime ? 'A' : '-', mtime ? 'M' : '-', length ? 'L' : '-');
if (atime || mtime)
{
time_t now = time (NULL);
if (read && atime)
handle->shared->atime = now;
if (!read && mtime)
handle->shared->mtime = now;
}
if (length)
{
handle->shared->size.count =
rtems_rfs_block_map_count (rtems_rfs_file_map (handle));
handle->shared->size.offset =
rtems_rfs_block_map_size_offset (rtems_rfs_file_map (handle));
}
return rc;
}
int
rtems_rfs_file_io_start (rtems_rfs_file_handle* handle,
size_t* available,
bool read)
{
size_t size;
if (rtems_rfs_trace (RTEMS_RFS_TRACE_FILE_IO))
printf ("rtems-rfs: file-io: start: %s pos=%" PRIu32 ":%" PRIu32 "\n",
read ? "read" : "write", handle->bpos.bno, handle->bpos.boff);
if (!rtems_rfs_buffer_handle_has_block (&handle->buffer))
{
rtems_rfs_buffer_block block;
bool request_read;
int rc;
request_read = read;
rc = rtems_rfs_block_map_find (rtems_rfs_file_fs (handle),
rtems_rfs_file_map (handle),
rtems_rfs_file_bpos (handle),
&block);
if (rc > 0)
{
/*
* Has the read reached the EOF ?
*/
if (read && (rc == ENXIO))
{
*available = 0;
return 0;
}
if (rc != ENXIO)
return rc;
if (rtems_rfs_trace (RTEMS_RFS_TRACE_FILE_IO))
printf ("rtems-rfs: file-io: start: grow\n");
rc = rtems_rfs_block_map_grow (rtems_rfs_file_fs (handle),
rtems_rfs_file_map (handle),
1, &block);
if (rc > 0)
return rc;
request_read = false;
}
else
{
/*
* If this is a write check if the write starts within a block or the
* amount of data is less than a block size. If it is read the block
* rather than getting a block to fill.
*/
if (!read &&
(rtems_rfs_file_block_offset (handle) ||
(*available < rtems_rfs_fs_block_size (rtems_rfs_file_fs (handle)))))
request_read = true;
}
if (rtems_rfs_trace (RTEMS_RFS_TRACE_FILE_IO))
printf ("rtems-rfs: file-io: start: block=%" PRIu32 " request-read=%s\n",
block, request_read ? "yes" : "no");
rc = rtems_rfs_buffer_handle_request (rtems_rfs_file_fs (handle),
rtems_rfs_file_buffer (handle),
block, request_read);
if (rc > 0)
return rc;
}
if (read
&& rtems_rfs_block_map_last (rtems_rfs_file_map (handle))
&& rtems_rfs_block_map_size_offset (rtems_rfs_file_map (handle)))
size = rtems_rfs_block_map_size_offset (rtems_rfs_file_map (handle));
else
size = rtems_rfs_fs_block_size (rtems_rfs_file_fs (handle));
*available = size - rtems_rfs_file_block_offset (handle);
if (rtems_rfs_trace (RTEMS_RFS_TRACE_FILE_IO))
printf ("rtems-rfs: file-io: start: available=%zu (%zu)\n",
*available, size);
return 0;
}
