From e6e6262f457cfe4e2fe20874e0456f7e8242502d Mon Sep 17 00:00:00 2001
From: Mark Pizzolato <mark@infocomm.com>
Date: Tue, 22 Jan 2013 20:59:49 -0800
Subject: [PATCH] Fix ordering of thread activities while detaching disks and
 tapes

---
 sim_disk.c | 15 ++++++++++++---
 sim_tape.c |  5 ++++-
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/sim_disk.c b/sim_disk.c
index cf576f77..3bb9aed5 100644
--- a/sim_disk.c
+++ b/sim_disk.c
@@ -447,6 +447,8 @@ return SCPE_NOFNC;
 struct disk_context *ctx = (struct disk_context *)uptr->disk_ctx;
 pthread_attr_t attr;
 
+sim_debug (ctx->dbit, ctx->dptr, "sim_disk_set_async(unit=%d)\n", (int)(uptr-ctx->dptr->units));
+
 ctx->asynch_io = sim_asynch_enabled;
 ctx->asynch_io_latency = latency;
 if (ctx->asynch_io) {
@@ -482,6 +484,8 @@ struct disk_context *ctx = (struct disk_context *)uptr->disk_ctx;
 /* make sure device exists */
 if (!ctx) return SCPE_UNATT;
 
+sim_debug (ctx->dbit, ctx->dptr, "sim_disk_clr_async(unit=%d)\n", (int)(uptr-ctx->dptr->units));
+
 if (ctx->asynch_io) {
     pthread_mutex_lock (&ctx->io_lock);
     ctx->asynch_io = 0;
@@ -971,6 +975,7 @@ ctx->capac_factor = ((dptr->dwidth / dptr->aincr) == 16) ? 2 : 1; /* save capaci
 ctx->xfer_element_size = (uint32)xfer_element_size;     /* save xfer_element_size */
 ctx->dptr = dptr;                                       /* save DEVICE pointer */
 ctx->dbit = dbit;                                       /* save debug bit */
+sim_debug (ctx->dbit, ctx->dptr, "sim_disk_attach(unit=%d,filename='%s')\n", (int)(uptr-ctx->dptr->units), uptr->filename);
 ctx->auto_format = auto_format;                         /* save that we auto selected format */
 ctx->storage_sector_size = (uint32)sector_size;         /* Default */
 if (sim_switches & SWMASK ('R')) {                      /* read only? */
@@ -1092,10 +1097,14 @@ int (*close_function)(FILE *f);
 FILE *fileref;
 t_bool auto_format;
 
-if (uptr == NULL)
+if ((uptr == NULL) || !(uptr->flags & UNIT_ATT))
     return SCPE_IERR;
+
 ctx = (struct disk_context *)uptr->disk_ctx;
 fileref = uptr->fileref;
+
+sim_debug (ctx->dbit, ctx->dptr, "sim_disk_detach(unit=%d,filename='%s')\n", (int)(uptr-ctx->dptr->units), uptr->filename);
+
 switch (DK_GET_FMT (uptr)) {                            /* case on format */
     case DKUF_F_STD:                                    /* Simh */
         close_function = fclose;
@@ -1117,11 +1126,11 @@ if (NULL == find_dev_from_unit (uptr))
     return SCPE_OK;
 auto_format = ctx->auto_format;
 
-sim_disk_clr_async (uptr);
-
 if (uptr->io_flush)
     uptr->io_flush (uptr);                              /* flush buffered data */
 
+sim_disk_clr_async (uptr);
+
 uptr->flags &= ~(UNIT_ATT | UNIT_RO);
 uptr->dynflags &= ~UNIT_NO_FIO;
 free (uptr->filename);
diff --git a/sim_tape.c b/sim_tape.c
index 8d44d535..9c7e42d7 100644
--- a/sim_tape.c
+++ b/sim_tape.c
@@ -488,11 +488,14 @@ t_stat sim_tape_detach (UNIT *uptr)
 uint32 f = MT_GET_FMT (uptr);
 t_stat r;
 
-sim_tape_clr_async (uptr);
+if ((uptr == NULL) || !(uptr->flags & UNIT_ATT))
+    return SCPE_IERR;
 
 if (uptr->io_flush)
     uptr->io_flush (uptr);                              /* flush buffered data */
 
+sim_tape_clr_async (uptr);
+
 r = detach_unit (uptr);                                 /* detach unit */
 if (r != SCPE_OK)
     return r;