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Add write completion loop to VFS server and libc

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Loop at the VFS server and libc VFS plugin on partial writes. This
implies that the VFS server will not process successive packets for an
open node until a write packet has been processed completely. The libc
will now supspend and reissue write requests to the VFS until the write
has been submitted completely.

Ref #2303
Fix #2971
This commit is contained in:
Ehmry - 2019-06-04 18:22:48 +02:00
parent f6d22088f2
commit efe39ab077
2 changed files with 19 additions and 7 deletions
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12
repos/libports/src/lib/libc/vfs_plugin.cc
View File

@ -445,7 +445,7 @@ ssize_t Libc::Vfs_plugin::write(Libc::File_descriptor *fd, const void *buf,
Vfs::Vfs_handle *handle;
void const *buf;
::size_t count;
::size_t const count;
Vfs::file_size &out_count;
Result &out_result;
@ -458,14 +458,16 @@ ssize_t Libc::Vfs_plugin::write(Libc::File_descriptor *fd, const void *buf,
bool suspend() override
{
Vfs::file_size out = 0;
try {
out_result = VFS_THREAD_SAFE(handle->fs().write(handle, (char const *)buf,
count, out_count));
retry = false;
out_result = VFS_THREAD_SAFE(handle->fs().write(handle, (char const *)buf+out_count,
count - out_count, out));
} catch (Vfs::File_io_service::Insufficient_buffer) {
retry = true;
out_result = Result::WRITE_OK;
}
out_count += out;
retry = (out_result == Result::WRITE_OK) && (out_count < count);
return retry;
}
} check(handle, buf, count, out_count, out_result);

14
repos/os/src/server/vfs/node.h
View File

@ -251,6 +251,8 @@ class Vfs_server::Io_node : public Vfs_server::Node,
if (result == Write_result::WRITE_OK) {
mark_as_updated();
_packet.succeeded(true);
} else {
_packet.succeeded(false);
}
}
catch (Vfs::File_io_service::Insufficient_buffer)
@ -609,6 +611,8 @@ class Vfs_server::File : public Io_node
char const *_leaf_path = nullptr; /* offset pointer to Node::_path */
file_size _write_offset { 0 };
inline
seek_off_t seek_tail(file_size count)
{
@ -648,9 +652,15 @@ class Vfs_server::File : public Io_node
if (seek_offset == (seek_off_t)SEEK_TAIL)
seek_offset = seek_tail(count);
bool result = _vfs_write(_stream.packet_content(_packet),
count, seek_offset, out_count);
bool result = _vfs_write(_stream.packet_content(_packet)+_write_offset,
count-_write_offset, seek_offset, out_count);
if (result) {
/* loop until the write completes or produces an error */
if (_packet.succeeded() && ((out_count+_write_offset) < count)) {
_write_offset += out_count;
return false;
}
_write_offset = 0;
_ack_packet(out_count);
if (out_count > 0) {
mark_as_updated();