int
rtems_rfs_file_set_size (rtems_rfs_file_handle* handle,
rtems_rfs_pos new_size)
{
rtems_rfs_block_map* map = rtems_rfs_file_map (handle);
rtems_rfs_pos size;
int rc;
if (rtems_rfs_trace (RTEMS_RFS_TRACE_FILE_IO))
printf ("rtems-rfs: file-set-size: size=%" PRIu64 "\n", new_size);
size = rtems_rfs_file_size (handle);
/*
* If the file is same size do nothing else grow or shrink it ?
*
* If the file does not change size do not update the times.
*/
if (size != new_size)
{
/*
* Short cut for the common truncate on open call.
*/
if (new_size == 0)
{
rc = rtems_rfs_block_map_free_all (rtems_rfs_file_fs (handle), map);
if (rc > 0)
return rc;
}
else
{
if (size < new_size)
{
/*
* Grow. Fill with 0's.
*/
rtems_rfs_pos count;
uint32_t length;
bool read_block;
count = new_size - size;
length = rtems_rfs_fs_block_size (rtems_rfs_file_fs (handle));
read_block = false;
while (count)
{
rtems_rfs_buffer_block block;
rtems_rfs_block_pos bpos;
uint8_t* dst;
/*
* Get the block position for the current end of the file as seen by
* the map. If not found and the EOF grow the map then fill the block
* with 0.
*/
rtems_rfs_block_size_get_bpos (rtems_rfs_block_map_size (map), &bpos);
rc = rtems_rfs_block_map_find (rtems_rfs_file_fs (handle),
map, &bpos, &block);
if (rc > 0)
{
/*
* Have we reached the EOF ?
*/
if (rc != ENXIO)
return rc;
rc = rtems_rfs_block_map_grow (rtems_rfs_file_fs (handle),
map, 1, &block);
if (rc > 0)
return rc;
}
if (count < (length - bpos.boff))
{
length = count + bpos.boff;
read_block = true;
rtems_rfs_block_map_set_size_offset (map, length);
}
else
{
rtems_rfs_block_map_set_size_offset (map, 0);
}
/*
* Only read the block if the length is not the block size.
*/
rc = rtems_rfs_buffer_handle_request (rtems_rfs_file_fs (handle),
rtems_rfs_file_buffer (handle),
block, read_block);
if (rc > 0)
return rc;
dst = rtems_rfs_buffer_data (&handle->buffer);
memset (dst + bpos.boff, 0, length - bpos.boff);
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)
return rc;
count -= length - bpos.boff;
}
}
else
{
/*
* Shrink
*/
rtems_rfs_block_no blocks;
uint32_t offset;
blocks =
rtems_rfs_block_map_count (map) -
(((new_size - 1) /
rtems_rfs_fs_block_size (rtems_rfs_file_fs (handle))) + 1);
offset =
new_size % rtems_rfs_fs_block_size (rtems_rfs_file_fs (handle));
if (blocks)
{
int rc;
rc = rtems_rfs_block_map_shrink (rtems_rfs_file_fs (handle),
rtems_rfs_file_map (handle),
blocks);
if (rc > 0)
return rc;
}
rtems_rfs_block_map_set_size_offset (map, offset);
if (rtems_rfs_block_pos_past_end (rtems_rfs_file_bpos (handle),
rtems_rfs_block_map_size (map)))
rtems_rfs_block_size_get_bpos (rtems_rfs_block_map_size (map),
rtems_rfs_file_bpos (handle));
}
}
handle->shared->size.count = rtems_rfs_block_map_count (map);
handle->shared->size.offset = rtems_rfs_block_map_size_offset (map);
if (rtems_rfs_file_update_mtime (handle))
handle->shared->mtime = time (NULL);
}
return 0;
}
int
rtems_rfs_block_map_shrink (rtems_rfs_file_system* fs,
rtems_rfs_block_map* map,
size_t blocks)
{
if (rtems_rfs_trace (RTEMS_RFS_TRACE_BLOCK_MAP_SHRINK))
printf ("rtems-rfs: block-map-shrink: entry: blocks=%zd count=%" PRIu32 "\n",
blocks, map->size.count);
if (map->size.count == 0)
return 0;
if (blocks > map->size.count)
blocks = map->size.count;
while (blocks)
{
rtems_rfs_block_no block;
rtems_rfs_block_no block_to_free;
int rc;
block = map->size.count - 1;
if (block < RTEMS_RFS_INODE_BLOCKS)
{
/*
* We have less than RTEMS_RFS_INODE_BLOCKS so they are held in the
* inode.
*/
block_to_free = map->blocks[block];
map->blocks[block] = 0;
}
else
{
/*
* Single indirect access is occuring. It could still be doubly indirect.
*
* The 'direct' variable is the offset in to the indirect table of
* blocks, and 'singly' is the inode block index of the singly indirect
* table of block numbers.
*/
rtems_rfs_block_no direct;
rtems_rfs_block_no singly;
direct = block % fs->blocks_per_block;
singly = block / fs->blocks_per_block;
if (block < fs->block_map_singly_blocks)
{
/*
* Request the indirect block and then obtain the block number from the
* indirect block.
*/
rc = rtems_rfs_buffer_handle_request (fs, &map->singly_buffer,
map->blocks[singly], true);
if (rc > 0)
return rc;
block_to_free = rtems_rfs_block_get_number (&map->singly_buffer,
direct);
rc = rtems_rfs_block_map_indirect_shrink (fs, map, &map->singly_buffer,
singly, direct);
if (rc)
return rc;
}
else if (block < fs->block_map_doubly_blocks)
{
/*
* Doubly indirect tables are being used. The 'doubly' variable is the
* index in to the inode's block table and points to a singly indirect
* table of block numbers. The 'doubly_singly' variable is the index
* into the doubly indirect table pointing to the singly indirect table
* of block numbers that form the map. This is used later to determine
* if the current doubly indirect table needs to be freed. The 'direct'
* value is still valid for doubly indirect tables.
*/
rtems_rfs_block_no doubly;
rtems_rfs_block_no doubly_singly;
doubly = singly / fs->blocks_per_block;
doubly_singly = singly % fs->blocks_per_block;
rc = rtems_rfs_buffer_handle_request (fs, &map->doubly_buffer,
map->blocks[doubly], true);
if (rc > 0)
return rc;
singly = rtems_rfs_block_get_number (&map->doubly_buffer,
doubly_singly);
/*
* Read the singly indirect table and get the block number.
*/
rc = rtems_rfs_buffer_handle_request (fs, &map->singly_buffer,
singly, true);
if (rc > 0)
return rc;
block_to_free = rtems_rfs_block_get_number (&map->singly_buffer,
direct);
if (direct == 0)
{
rc = rtems_rfs_group_bitmap_free (fs, false, singly);
if (rc > 0)
return rc;
map->last_map_block = singly;
rc = rtems_rfs_block_map_indirect_shrink (fs, map, &map->doubly_buffer,
doubly, doubly_singly);
if (rc)
return rc;
}
}
else
{
rc = EIO;
break;
}
}
rc = rtems_rfs_group_bitmap_free (fs, false, block_to_free);
if (rc > 0)
return rc;
map->size.count--;
map->size.offset = 0;
map->last_data_block = block_to_free;
map->dirty = true;
blocks--;
}
if (map->size.count == 0)
{
map->last_map_block = 0;
map->last_data_block = 0;
}
/*
* Keep the position inside the map.
*/
if (rtems_rfs_block_pos_past_end (&map->bpos, &map->size))
rtems_rfs_block_size_get_bpos (&map->size, &map->bpos);
return 0;
}
