Avoid closing files in gc/monitor callbacks

Closing files in these callbacks could block scheduler progress
and cause major system instability. We now defer these operations
to a dedicated process instead.

This process may in turn block forever and prevent further orphaned
files from being closed, but it will keep the emulator itself from
misbehaving.

1 files changed, 5 insertions, 2 deletions

diff --git a/erts/emulator/nifs/unix/unix_prim_file.c b/erts/emulator/nifs/unix/unix_prim_file.c
index dea73db18a..169b193993 100644
--- a/erts/emulator/nifs/unix/unix_prim_file.c
+++ b/erts/emulator/nifs/unix/unix_prim_file.c
@@ -202,21 +202,24 @@ posix_errno_t efile_open(const efile_path_t *path, enum efile_modes_t modes,
     return errno;
 }
 
-int efile_close(efile_data_t *d) {
+int efile_close(efile_data_t *d, posix_errno_t *error) {
     efile_unix_t *u = (efile_unix_t*)d;
     int fd;
 
+    ASSERT(enif_thread_type() == ERL_NIF_THR_DIRTY_IO_SCHEDULER);
     ASSERT(erts_atomic32_read_nob(&d->state) == EFILE_STATE_CLOSED);
     ASSERT(u->fd != -1);
 
     fd = u->fd;
     u->fd = -1;
 
+    enif_release_resource(d);
+
     /* close(2) either always closes (*BSD, Linux) or leaves the fd in an
      * undefined state (POSIX 2008, Solaris), so we must not retry on EINTR. */
 
     if(close(fd) < 0) {
-        u->common.posix_errno = errno;
+        *error = errno;
         return 0;
     }