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mirror: abandon signals are now honoured outside of the remote end being readable / writable

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This commit is contained in:
nick
2013-08-12 15:30:21 +01:00
parent 41facd2ccf
commit c6764b0de1
3 changed files with 57 additions and 29 deletions
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63
src/mirror.c
View File

@@ -73,6 +73,7 @@ struct mirror_ctrl {
ev_io read_watcher;
ev_io write_watcher;
ev_timer timeout_watcher;
ev_io abandon_watcher;
/* Use this to keep track of what we're copying at any moment */
struct xfer xfer;
@@ -94,6 +95,12 @@ struct mirror * mirror_alloc(
mirror->action_at_finish = action_at_finish;
mirror->commit_signal = commit_signal;
mirror->commit_state = MS_UNKNOWN;
mirror->abandon_signal = self_pipe_create();
if ( mirror->abandon_signal == NULL ) {
warn( "Couldn't create mirror abandon signal" );
return NULL;
}
return mirror;
}
@@ -195,6 +202,7 @@ struct mirror * mirror_create(
void mirror_destroy( struct mirror *mirror )
{
NULLCHECK( mirror );
self_pipe_destroy( mirror->abandon_signal );
free(mirror->connect_to);
free(mirror->connect_from);
free(mirror->dirty_map);
@@ -428,13 +436,6 @@ static void mirror_write_cb( struct ev_loop *loop, ev_io *w, int revents )
return;
}
/* TODO: This needs to be its own event, not checked here */
if ( ctrl->mirror->signal_abandon ) {
debug("Abandon message received" );
ev_break( loop, EVBREAK_ONE );
return;
}
debug( "Mirror write callback invoked with events %d. fd: %i", revents, ctrl->mirror->client );
if ( xfer->written < hdr_size ) {
@@ -509,13 +510,6 @@ static void mirror_read_cb( struct ev_loop *loop, ev_io *w, int revents )
return;
}
/* TODO: This needs to be its own event, not checked here */
if ( m->signal_abandon ) {
debug("Abandon message received" );
ev_break( loop, EVBREAK_ONE );
return;
}
struct nbd_reply rsp;
ssize_t count;
uint64_t left = sizeof( struct nbd_reply_raw ) - xfer->read;
@@ -645,6 +639,22 @@ void mirror_timeout_cb( struct ev_loop *loop, ev_timer *w __attribute__((unused)
return;
}
void mirror_abandon_cb( struct ev_loop *loop, ev_io *w, int revents )
{
struct mirror_ctrl* ctrl = (struct mirror_ctrl*) w->data;
NULLCHECK( ctrl );
if ( !(revents & EV_READ ) ) {
warn( "Mirror abandon called but no abandon event signalled" );
return;
}
debug( "Abandon message received" );
self_pipe_signal_clear( ctrl->mirror->abandon_signal );
ev_break( loop, EVBREAK_ONE );
return;
}
void mirror_run( struct server *serve )
{
NULLCHECK( serve );
@@ -686,6 +696,11 @@ void mirror_run( struct server *serve )
ev_init( &ctrl.timeout_watcher, mirror_timeout_cb );
ctrl.timeout_watcher.repeat = MS_REQUEST_LIMIT_SECS_F ;
ev_init( &ctrl.abandon_watcher, mirror_abandon_cb );
ev_io_set( &ctrl.abandon_watcher, ctrl.mirror->abandon_signal->read_fd, EV_READ );
ctrl.write_watcher.data = (void*) &ctrl;
ev_io_start( ctrl.ev_loop, &ctrl.abandon_watcher );
ERROR_UNLESS(
mirror_setup_next_xfer( &ctrl ),
"Couldn't find first transfer for mirror!"
@@ -855,7 +870,7 @@ void * mirror_super_runner( void * serve_uncast )
int first_pass = 1;
int should_retry = 0;
int success = 0;
int success = 0, abandoned = 0;
struct mirror * mirror = serve->mirror;
struct mirror_super * super = serve->mirror_super;
@@ -895,18 +910,26 @@ void * mirror_super_runner( void * serve_uncast )
debug("Supervisor waiting for mirror thread" );
pthread_join( mirror->thread, NULL );
/* If we can't connect to the remote end, the watcher for the abandon
* signal never gets installed at the moment, which is why we also check
* it here. */
abandoned =
mirror_get_state( mirror ) == MS_ABANDONED ||
self_pipe_signal_clear( mirror->abandon_signal );
success = MS_DONE == mirror_get_state( mirror );
if( success ){
info( "Mirror supervisor success, exiting" ); }
else if ( mirror->signal_abandon ) {
info( "Mirror supervisor success, exiting" );
} else if ( abandoned ) {
info( "Mirror abandoned" );
should_retry = 0;
}
else if (should_retry){
} else if ( should_retry ) {
info( "Mirror failed, retrying" );
} else {
info( "Mirror failed before commit, giving up" );
}
else { info( "Mirror failed before commit, giving up" ); }
first_pass = 0;

8
src/mirror.h
View File

@@ -52,6 +52,7 @@ enum mirror_state {
MS_UNKNOWN,
MS_INIT,
MS_GO,
MS_ABANDONED,
MS_DONE,
MS_FAIL_CONNECT,
MS_FAIL_REJECTED,
@@ -61,8 +62,10 @@ enum mirror_state {
struct mirror {
pthread_t thread;
/* set to 1, then join thread to make mirror terminate early */
int signal_abandon;
/* Signal to this then join the thread if you want to abandon mirroring */
struct self_pipe * abandon_signal;
union mysockaddr * connect_to;
union mysockaddr * connect_from;
int client;
@@ -126,5 +129,6 @@ struct mirror_super * mirror_super_create(
struct mbox * state_mbox
);
void * mirror_super_runner( void * serve_uncast );
#endif

15
src/serve.c
View File

@@ -853,13 +853,14 @@ void server_abandon_mirror( struct server * serve )
NULLCHECK( serve );
if ( serve->mirror_super ) {
/* FIXME: AWOOGA! RACE!
* We can set signal_abandon after mirror_super has
* checked it, but before the reset. This would lead to
* a hang. However, mirror_reset doesn't change the
* signal_abandon flag, so it'll just terminate early on
* the next pass.
* */
serve->mirror->signal_abandon = 1;
* We can set abandon_signal after mirror_super has checked it, but
* before the reset. However, mirror_reset doesn't clear abandon_signal
* so it'll just terminate early on the next pass. */
ERROR_UNLESS(
self_pipe_signal( serve->mirror->abandon_signal ),
"Failed to signal abandon to mirror"
);
pthread_t tid = serve->mirror_super->thread;
pthread_join( tid, NULL );
debug( "Mirror thread %p pthread_join returned", tid );