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fixed error handling in read_into_piece

This commit is contained in:
Arvid Norberg 2009-11-28 03:14:08 +00:00
parent af8234b035
commit ab4b7f99ad
1 changed files with 88 additions and 53 deletions
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139
src/disk_io_thread.cpp
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@ -798,105 +798,134 @@ namespace libtorrent
int disk_io_thread::read_into_piece(cached_piece_entry& p, int start_block
, int options, int num_blocks, mutex::scoped_lock& l)
{
TORRENT_ASSERT(num_blocks > 0);
int piece_size = p.storage->info()->piece_size(p.piece);
int blocks_in_piece = (piece_size + m_block_size - 1) / m_block_size;
int end_block = start_block;
int num_read = 0;
int iov_counter = 0;
file::iovec_t* iov = TORRENT_ALLOCA(file::iovec_t, (std::min)(blocks_in_piece - start_block, num_blocks));
int piece_offset = start_block * m_block_size;
int ret = 0;
boost::scoped_array<char> buf;
for (int i = start_block; i < blocks_in_piece
&& (in_use() < m_settings.cache_size
|| (options & ignore_cache_size)); ++i)
&& ((options & ignore_cache_size)
|| in_use() < m_settings.cache_size); ++i)
{
int block_size = (std::min)(piece_size - piece_offset, m_block_size);
TORRENT_ASSERT(piece_offset <= piece_size);
// this is a block that is already allocated
// stop allocating and don't read more than
// what we've allocated now
if (p.blocks[i].buf) break;
// free it an allocate a new one
if (p.blocks[i].buf)
{
free_buffer(p.blocks[i].buf);
--p.num_blocks;
--m_cache_stats.cache_size;
--m_cache_stats.read_cache_size;
}
p.blocks[i].buf = allocate_buffer("read cache");
// the allocation failed, break
if (p.blocks[i].buf == 0) break;
if (p.blocks[i].buf == 0)
{
free_piece(p, l);
return -1;
}
++p.num_blocks;
++m_cache_stats.cache_size;
++m_cache_stats.read_cache_size;
++end_block;
++num_read;
iov[iov_counter].iov_base = p.blocks[i].buf;
iov[iov_counter].iov_len = block_size;
++iov_counter;
piece_offset += m_block_size;
if (num_read >= num_blocks) break;
}
if (end_block == start_block) return -2;
if (end_block == start_block)
{
// something failed. Free all buffers
// we just allocated
free_piece(p, l);
return -2;
}
TORRENT_ASSERT(iov_counter <= (std::min)(blocks_in_piece - start_block, num_blocks));
// the buffer_size is the size of the buffer we need to read
// all these blocks.
const int buffer_size = (std::min)((end_block - start_block) * m_block_size
, piece_size - start_block * m_block_size);
TORRENT_ASSERT(buffer_size > 0);
TORRENT_ASSERT(buffer_size <= piece_size);
TORRENT_ASSERT(buffer_size + start_block * m_block_size <= piece_size);
boost::scoped_array<char> buf;
file::iovec_t* iov = 0;
int iov_counter = 0;
if (m_settings.coalesce_reads) buf.reset(new (std::nothrow) char[buffer_size]);
if (!buf) iov = TORRENT_ALLOCA(file::iovec_t, end_block - start_block);
int ret = 0;
if (m_settings.coalesce_reads)
buf.reset(new (std::nothrow) char[buffer_size]);
if (buf)
{
l.unlock();
file::iovec_t b = { buf.get(), buffer_size };
ret = p.storage->read_impl(&b, p.piece, start_block * m_block_size, 1);
l.lock();
if (p.storage->error()) return -1;
++m_cache_stats.reads;
if (p.storage->error())
{
free_piece(p, l);
return -1;
}
if (ret != buffer_size)
{
// this means the file wasn't big enough for this read
p.storage->get_storage_impl()->set_error(""
, error_code(errors::file_too_short, libtorrent_category));
free_piece(p, l);
return -1;
}
++m_cache_stats.reads;
}
int piece_offset = start_block * m_block_size;
int offset = 0;
for (int i = start_block; i < end_block; ++i)
for (int i = 0; i < iov_counter; ++i)
{
int block_size = (std::min)(piece_size - piece_offset, m_block_size);
if (p.blocks[i].buf == 0) break;
TORRENT_ASSERT(offset <= buffer_size);
TORRENT_ASSERT(piece_offset <= piece_size);
TORRENT_ASSERT(offset + block_size <= buffer_size);
if (buf)
{
std::memcpy(p.blocks[i].buf, buf.get() + offset, block_size);
TORRENT_ASSERT(iov[i].iov_base);
TORRENT_ASSERT(iov[i].iov_len > 0);
TORRENT_ASSERT(offset + iov[i].iov_len <= buffer_size);
std::memcpy(iov[i].iov_base, buf.get() + offset, iov[i].iov_len);
offset += iov[i].iov_len;
}
}
else
{
iov[iov_counter].iov_base = p.blocks[i].buf;
iov[iov_counter].iov_len = block_size;
++iov_counter;
}
offset += m_block_size;
piece_offset += m_block_size;
}
if (iov)
{
l.unlock();
ret = p.storage->read_impl(iov, p.piece, start_block * m_block_size, iov_counter);
l.lock();
if (p.storage->error()) return -1;
++m_cache_stats.reads;
if (p.storage->error())
{
free_piece(p, l);
return -1;
}
if (ret != buffer_size)
{
// this means the file wasn't big enough for this read
p.storage->get_storage_impl()->set_error(""
, error_code(errors::file_too_short, libtorrent_category));
free_piece(p, l);
return -1;
}
++m_cache_stats.reads;
}
TORRENT_ASSERT(ret <= buffer_size);
TORRENT_ASSERT(ret == buffer_size || p.storage->error());
return (ret != buffer_size) ? -1 : ret;
TORRENT_ASSERT(ret == buffer_size);
return ret;
}
// returns -1 on read error, -2 on out of memory error or the number of bytes read
@ -923,10 +952,7 @@ namespace libtorrent
if (!p.blocks) return -1;
int ret = read_into_piece(p, 0, ignore_cache_size, INT_MAX, l);
if (ret < 0)
free_piece(p, l);
else
m_read_pieces.push_back(p);
if (ret >= 0) m_read_pieces.push_back(p);
return ret;
}
@ -961,10 +987,7 @@ namespace libtorrent
if (!p.blocks) return -1;
int ret = read_into_piece(p, start_block, 0, blocks_to_read, l);
if (ret < 0)
free_piece(p, l);
else
m_read_pieces.push_back(p);
if (ret >= 0) m_read_pieces.push_back(p);
return ret;
}
@ -1049,6 +1072,20 @@ namespace libtorrent
bool hit = true;
int ret = 0;
int piece_size = j.storage->info()->piece_size(j.piece);
int blocks_in_piece = (piece_size + m_block_size - 1) / m_block_size;
if (p != m_read_pieces.end() && p->num_blocks != blocks_in_piece)
{
// we have the piece in the cache, but not all of the blocks
ret = read_into_piece(*p, 0, ignore_cache_size, blocks_in_piece, l);
hit = false;
if (ret < 0) return ret;
TORRENT_ASSERT(!m_read_pieces.empty());
TORRENT_ASSERT(p->piece == j.piece);
TORRENT_ASSERT(p->storage == j.storage);
}
// if the piece cannot be found in the cache,
// read the whole piece starting at the block
// we got a request for.
@ -1066,9 +1103,6 @@ namespace libtorrent
hasher ctx;
int piece_size = j.storage->info()->piece_size(j.piece);
int blocks_in_piece = (piece_size + m_block_size - 1) / m_block_size;
for (int i = 0; i < blocks_in_piece; ++i)
{
TORRENT_ASSERT(p->blocks[i].buf);
@ -1683,6 +1717,7 @@ namespace libtorrent
if (p->blocks[block].buf)
{
free_buffer(p->blocks[block].buf);
--m_cache_stats.cache_size;
--p->num_blocks;
}
p->blocks[block].buf = j.buffer;