From 8b3bcc5a126dfbc4f7152345e7c6ebcadbaa9eb6 Mon Sep 17 00:00:00 2001 From: Patrik Nyblom Date: Tue, 15 Jan 2013 12:03:20 +0100 Subject: Alternative solution to the efile_drv crash on exit --- erts/emulator/drivers/common/efile_drv.c | 93 +++++++++++++++++++++++--------- 1 file changed, 68 insertions(+), 25 deletions(-) (limited to 'erts/emulator') diff --git a/erts/emulator/drivers/common/efile_drv.c b/erts/emulator/drivers/common/efile_drv.c index 25b02db2c9..186af03eff 100644 --- a/erts/emulator/drivers/common/efile_drv.c +++ b/erts/emulator/drivers/common/efile_drv.c @@ -57,7 +57,7 @@ #define FILE_FADVISE 31 #define FILE_SENDFILE 32 #define FILE_FALLOCATE 33 - +#define FILE_CLOSE_ON_PORT_EXIT 34 /* Return codes */ #define FILE_RESP_OK 0 @@ -178,6 +178,7 @@ dt_private *get_dt_private(int); #define MUTEX_LOCK(m) do { IF_THRDS { TRACE_DRIVER; driver_pdl_lock(m); } } while (0) #define MUTEX_UNLOCK(m) do { IF_THRDS { TRACE_DRIVER; driver_pdl_unlock(m); } } while (0) #else +#define IF_THRDS if (0) #define MUTEX_INIT(m, p) #define MUTEX_LOCK(m) #define MUTEX_UNLOCK(m) @@ -429,6 +430,7 @@ struct t_data int level; void (*invoke)(void *); void (*free)(void *); + void *data_to_free; /* used by FILE_CLOSE_ON_PORT_EXIT only */ int again; int reply; #ifdef USE_VM_PROBES @@ -808,34 +810,25 @@ static void free_data(void *data) { struct t_data *d = (struct t_data *) data; - if (d->command == FILE_OPEN && d->is_fd_unused && d->fd != FILE_FD_INVALID) { - do_close(d->flags, d->fd); + switch (d->command) { + case FILE_OPEN: + if (d->is_fd_unused && d->fd != FILE_FD_INVALID) { + /* This is OK to do in scheduler thread because there can be no async op + ongoing for this fd here, as we exited during async open. + Ideally, this close should happen in an async thread too, but that would + require a substantial rewrite, as we are here because of a dead port and + cannot schedule async jobs for that port any more... */ + do_close(d->flags, d->fd); + } + break; + case FILE_CLOSE_ON_PORT_EXIT: + EF_FREE(d->data_to_free); + break; } EF_FREE(data); } -/********************************************************************* - * Driver entry point -> stop - */ -static void -file_stop(ErlDrvData e) -{ - file_descriptor* desc = (file_descriptor*)e; - - TRACE_C('p'); - - if (desc->fd != FILE_FD_INVALID) { - do_close(desc->flags, desc->fd); - desc->fd = FILE_FD_INVALID; - desc->flags = 0; - } - if (desc->read_binp) { - driver_free_binary(desc->read_binp); - } - EF_FREE(desc); -} - /* * Sends back an error reply to Erlang. @@ -2242,6 +2235,47 @@ static int lseek_flush_read(file_descriptor *desc, int *errp } +/********************************************************************* + * Driver entry point -> stop + * The close has to be scheduled on async thread, so that currently active + * async operation does not suddenly have the ground disappearing under their feet... + */ +static void +file_stop(ErlDrvData e) +{ + file_descriptor* desc = (file_descriptor*)e; + + TRACE_C('p'); + + IF_THRDS { + flush_read(desc); + if (desc->fd != FILE_FD_INVALID) { + struct t_data *d = EF_SAFE_ALLOC(sizeof(struct t_data)); + d->command = FILE_CLOSE_ON_PORT_EXIT; + d->reply = !0; + d->fd = desc->fd; + d->flags = desc->flags; + d->invoke = invoke_close; + d->free = free_data; + d->level = 2; + d->data_to_free = (void *) desc; + cq_enq(desc, d); + desc->fd = FILE_FD_INVALID; + desc->flags = 0; + cq_execute(desc); + } + } else { + if (desc->fd != FILE_FD_INVALID) { + do_close(desc->flags, desc->fd); + desc->fd = FILE_FD_INVALID; + desc->flags = 0; + } + if (desc->read_binp) { + driver_free_binary(desc->read_binp); + } + EF_FREE(desc); + } +} /********************************************************************* * Driver entry point -> ready_async @@ -2465,7 +2499,6 @@ file_async_ready(ErlDrvData e, ErlDrvThreadData data) } free_readdir(data); break; - /* See file_stop */ case FILE_CLOSE: if (d->reply) { TRACE_C('K'); @@ -2525,6 +2558,15 @@ file_async_ready(ErlDrvData e, ErlDrvThreadData data) } break; #endif + case FILE_CLOSE_ON_PORT_EXIT: + /* See file_stop. However this is never invoked after the port is killed. */ + free_data(data); + EF_FREE(desc); + desc = NULL; + /* This is it for this port, so just send dtrace and return, avoid doing anything to the freed data */ + DTRACE6(efile_drv_return, sched_i1, sched_i2, sched_utag, + command, result_ok, posix_errno); + return; default: abort(); } @@ -2535,6 +2577,7 @@ file_async_ready(ErlDrvData e, ErlDrvThreadData data) driver_set_timer(desc->port, desc->write_delay); } cq_execute(desc); + } -- cgit v1.2.3