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vfs: fix races in fs_file_system with pthreads

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Change metadata before submitting a packet. If the submitting thread is a
pthread, the metadata may be immediately change by the signal handler running
in the context of the entrypoint thread.
This commit is contained in:
Alexander Boettcher 2017-02-15 15:36:27 +01:00 committed by Christian Helmuth
parent 69c48a3626
commit 328da2975f
1 changed files with 19 additions and 13 deletions
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32
repos/os/src/lib/vfs/fs_file_system.h
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@ -161,14 +161,16 @@ class Vfs::Fs_file_system : public File_system
clipped_count,
seek_offset);
/* wait until packet was acknowledged */
handle.queued_read_state = Handle_state::Queued_state::QUEUED;
/* pass packet to server side */
source.submit_packet(packet_in);
/* wait until packet was acknowledged */
handle.queued_read_state = Handle_state::Queued_state::QUEUED;
do {
while (handle.queued_read_state != Handle_state::Queued_state::ACK)
{
_env.ep().wait_and_dispatch_one_signal();
} while (handle.queued_read_state != Handle_state::Queued_state::ACK);
}
/* obtain result packet descriptor with updated status info */
Packet_descriptor const packet_out = handle.queued_read_packet;
@ -211,14 +213,16 @@ class Vfs::Fs_file_system : public File_system
memcpy(source.packet_content(packet_in), buf, count);
/* wait until packet was acknowledged */
handle.queued_write_state = Handle_state::Queued_state::QUEUED;
/* pass packet to server side */
source.submit_packet(packet_in);
/* wait until packet was acknowledged */
handle.queued_write_state = Handle_state::Queued_state::QUEUED;
do {
while (handle.queued_write_state != Handle_state::Queued_state::ACK)
{
_env.ep().wait_and_dispatch_one_signal();
} while (handle.queued_write_state != Handle_state::Queued_state::ACK);
}
/* obtain result packet descriptor with updated status info */
Packet_descriptor const packet_out = handle.queued_write_packet;
@ -746,14 +750,14 @@ class Vfs::Fs_file_system : public File_system
::File_system::Packet_descriptor::READ,
clipped_count, handle->seek());
/* pass packet to server side */
source.submit_packet(packet);
handle->read_ready_state = Handle_state::Read_ready_state::IDLE;
handle->queued_read_state = Handle_state::Queued_state::QUEUED;
out_result = READ_QUEUED;
/* pass packet to server side */
source.submit_packet(packet);
return true;
}
@ -777,12 +781,13 @@ class Vfs::Fs_file_system : public File_system
memcpy(dst, source.packet_content(packet), read_num_bytes);
source.release_packet(packet);
handle->queued_read_state = Handle_state::Queued_state::IDLE;
handle->queued_read_packet = ::File_system::Packet_descriptor();
out_count = read_num_bytes;
source.release_packet(packet);
return READ_OK;
}
@ -811,9 +816,10 @@ class Vfs::Fs_file_system : public File_system
Packet_descriptor::READ_READY,
0, 0);
source.submit_packet(packet);
handle->read_ready_state = Handle_state::Read_ready_state::PENDING;
source.submit_packet(packet);
/*
* When the packet is acknowledged the application is notified via
* Io_response_handler::handle_io_response().