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server/vfs: set seek offset before executing write

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The seek offset has to be updated on partial writes according to the
current write position. Otherwise writes will override the content
at the initial offset.

Fixes #3780.
This commit is contained in:
Martin Stein 2020-06-09 17:53:58 +02:00 committed by Norman Feske
parent 04d8c859d8
commit 1e96510815
1 changed files with 13 additions and 6 deletions
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19
repos/os/src/server/vfs/node.h
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@ -300,6 +300,11 @@ class Vfs_server::Io_node : public Vfs_server::Node,
*/
Packet_descriptor _packet { };
/**
* Initial seek offset from where to start writing
*/
seek_off_t _initial_write_seek_offset { 0 };
protected:
Submit_result _submit_read_at(file_offset seek_offset)
@ -324,7 +329,7 @@ class Vfs_server::Io_node : public Vfs_server::Node,
if (!(_mode & WRITE_ONLY))
return Submit_result::DENIED;
_handle.seek(seek_offset);
_initial_write_seek_offset = seek_offset;
_packet_in_progress = true;
return Submit_result::ACCEPTED;
@ -398,10 +403,13 @@ class Vfs_server::Io_node : public Vfs_server::Node,
*
* \return number of consumed bytes
*/
file_size _execute_write(char const *src_ptr, size_t length)
file_size _execute_write(char const *src_ptr, size_t length,
seek_off_t write_pos)
{
file_size out_count = 0;
try {
_handle.seek(_initial_write_seek_offset + write_pos);
switch (_handle.fs().write(&_handle, src_ptr, length, out_count)) {
case Write_result::WRITE_ERR_AGAIN:
case Write_result::WRITE_ERR_WOULD_BLOCK:
@ -677,7 +685,7 @@ struct Vfs_server::Symlink : Io_node
{
size_t const count = _write_buffer.length();
if (_execute_write(_write_buffer.string(), count) == count)
if (_execute_write(_write_buffer.string(), count, 0) == count)
_acknowledge_as_success(count);
else
_acknowledge_as_failure();
@ -808,7 +816,8 @@ class Vfs_server::File : public Io_node
{
size_t const count = _packet.length() - _write_pos;
char const * const src_ptr = _payload_ptr.ptr + _write_pos;
size_t const consumed = _execute_write(src_ptr, count);
size_t const consumed = _execute_write(src_ptr, count,
_write_pos);
if (consumed == count) {
_acknowledge_as_success(count);
@ -837,8 +846,6 @@ class Vfs_server::File : public Io_node
/*
* Keep executing the write operation for the remaining bytes.
* The seek offset used for subsequent VFS write operations
* is incremented automatically by the VFS handle.
*/
_write_pos += consumed;
break;