libblockdriver: clear IPC only on stateful restart

This removes a race condition when the block driver performs a
complete restart after a crash (the new default). If any user of
the driver finds out its new endpoint and sends a request to the
new driver instance before this instance has had the chance to
initialize, then its initialization would clear all IPC state and
thereby erroneously cancel the incoming request. Clearing IPC
state is only desired upon a stateful restart (where the driver's
endpoint is retained). This information is now passed to and used
by libblockdriver accordingly.

diff --git a/common/include/minix/blockdriver.h b/common/include/minix/blockdriver.h
index ef0f00809e8260c9ce15f0336319e679e5491e62..588e7e5760788b59da5c1b0c98ecc0122f53aab7 100644 (file)
--- a/common/include/minix/blockdriver.h
+++ b/common/include/minix/blockdriver.h
@@ -32,7 +32,7 @@ struct blockdriver {
 /* Functions defined by libblockdriver. These can be used for both
  * singlethreaded and multithreaded drivers.
  */
-_PROTOTYPE( void blockdriver_announce, (void) );
+_PROTOTYPE( void blockdriver_announce, (int type) );
 
 #ifndef _BLOCKDRIVER_MT_API
 /* Additional functions for the singlethreaded version. These allow the driver

diff --git a/drivers/ahci/ahci.c b/drivers/ahci/ahci.c
index 75912841a996b691c203109de64fc4d5b849a2f1..1f21aa3414845e2afae805bf5135ab493f4a2b2b 100644 (file)
--- a/drivers/ahci/ahci.c
+++ b/drivers/ahci/ahci.c
@@ -2071,7 +2071,7 @@ PRIVATE void ahci_set_mapping(void)
 /*===========================================================================*
  *                             sef_cb_init_fresh                            *
  *===========================================================================*/
-PRIVATE int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *UNUSED(info))
+PRIVATE int sef_cb_init_fresh(int type, sef_init_info_t *UNUSED(info))
 {
        /* Initialize the driver.
         */
@@ -2093,7 +2093,7 @@ PRIVATE int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *UNUSED(info))
        ahci_set_mapping();
 
        /* Announce that we are up. */
-       blockdriver_announce();
+       blockdriver_announce(type);
 
        return OK;
 }

diff --git a/drivers/at_wini/at_wini.c b/drivers/at_wini/at_wini.c
index bc732207fa3be924b452d3fbbe132b5a01ee1c66..d03cafcbef259f998483dd1b29270fa557867743 100644 (file)
--- a/drivers/at_wini/at_wini.c
+++ b/drivers/at_wini/at_wini.c
@@ -257,7 +257,7 @@ PRIVATE void sef_local_startup(void)
 /*===========================================================================*
  *                         sef_cb_init_fresh                                *
  *===========================================================================*/
-PRIVATE int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *UNUSED(info))
+PRIVATE int sef_cb_init_fresh(int type, sef_init_info_t *UNUSED(info))
 {
 /* Initialize the at_wini driver. */
   system_hz = sys_hz();
@@ -272,7 +272,7 @@ PRIVATE int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *UNUSED(info))
   init_params();
 
   /* Announce we are up! */
-  blockdriver_announce();
+  blockdriver_announce(type);
 
   return(OK);
 }

diff --git a/drivers/bios_wini/bios_wini.c b/drivers/bios_wini/bios_wini.c
index 733fbe600cdf1d825ba738c520226752c3977ca8..674e1728deb572f309f46e8b50ecf1daf393ddf2 100644 (file)
--- a/drivers/bios_wini/bios_wini.c
+++ b/drivers/bios_wini/bios_wini.c
@@ -122,7 +122,7 @@ PRIVATE void sef_local_startup(void)
 /*===========================================================================*
  *                         sef_cb_init_fresh                                *
  *===========================================================================*/
-PRIVATE int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *UNUSED(info))
+PRIVATE int sef_cb_init_fresh(int type, sef_init_info_t *UNUSED(info))
 {
 /* Initialize the bios_wini driver. */
   long v;
@@ -132,7 +132,7 @@ PRIVATE int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *UNUSED(info))
   remap_first = v;
 
   /* Announce we are up! */
-  blockdriver_announce();
+  blockdriver_announce(type);
 
   return(OK);
 }

diff --git a/drivers/filter/main.c b/drivers/filter/main.c
index a2a6a404d97981b04e937ddbd4d25c9aa5e69cba..602870a3b436099407c93a20e53203f3ee2f631d 100644 (file)
--- a/drivers/filter/main.c
+++ b/drivers/filter/main.c
@@ -443,9 +443,9 @@ PRIVATE void sef_local_startup(void)
 /*===========================================================================*
  *                         sef_cb_init_fresh                                *
  *===========================================================================*/
-PRIVATE int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *UNUSED(info))
+PRIVATE int sef_cb_init_fresh(int type, sef_init_info_t *UNUSED(info))
 {
-/* Initialize the filter driver. */
+       /* Initialize the filter driver. */
        int r;
 
        r = parse_arguments(env_argc, env_argv);
@@ -468,7 +468,7 @@ PRIVATE int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *UNUSED(info))
        }
 
        /* Announce we are up! */
-       blockdriver_announce();
+       blockdriver_announce(type);
 
        return(OK);
 }

diff --git a/drivers/floppy/floppy.c b/drivers/floppy/floppy.c
index 4a026741ff16bd3fa0c50bef01e5b8ffdefc394c..01c2bdacd224aaf2f1ef56eaaba040fbc4f4dcbf 100644 (file)
--- a/drivers/floppy/floppy.c
+++ b/drivers/floppy/floppy.c
@@ -331,7 +331,7 @@ PRIVATE void sef_local_startup(void)
 /*===========================================================================*
  *                         sef_cb_init_fresh                                *
  *===========================================================================*/
-PRIVATE int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *UNUSED(info))
+PRIVATE int sef_cb_init_fresh(int type, sef_init_info_t *UNUSED(info))
 {
 /* Initialize the floppy driver. */
   struct floppy *fp;
@@ -363,7 +363,7 @@ PRIVATE int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *UNUSED(info))
        panic("Couldn't enable IRQs: %d", s);
 
   /* Announce we are up! */
-  blockdriver_announce();
+  blockdriver_announce(type);
 
   return(OK);
 }

diff --git a/lib/libblockdriver/driver.c b/lib/libblockdriver/driver.c
index d97b58542d88dc50f1a52e464e1afae46ba662cc..b72223b27677695a976bfe1c676edab2c7c1f959 100644 (file)
--- a/lib/libblockdriver/driver.c
+++ b/lib/libblockdriver/driver.c
@@ -92,7 +92,7 @@ PRIVATE void set_open_dev(int device)
 /*===========================================================================*
  *                             blockdriver_announce                         *
  *===========================================================================*/
-PUBLIC void blockdriver_announce(void)
+PUBLIC void blockdriver_announce(int type)
 {
 /* Announce we are up after a fresh start or a restart. */
   int r;
@@ -102,12 +102,15 @@ PUBLIC void blockdriver_announce(void)
 
   /* Callers are allowed to use sendrec to communicate with drivers.
    * For this reason, there may blocked callers when a driver restarts.
-   * Ask the kernel to unblock them (if any).
+   * Ask the kernel to unblock them (if any). Note that most block drivers
+   * will not restart statefully, and thus will skip this code.
    */
+  if (type == SEF_INIT_RESTART) {
 #if USE_STATECTL
-  if ((r = sys_statectl(SYS_STATE_CLEAR_IPC_REFS)) != OK)
-       panic("blockdriver_init: sys_statectl failed: %d", r);
+       if ((r = sys_statectl(SYS_STATE_CLEAR_IPC_REFS)) != OK)
+               panic("blockdriver_init: sys_statectl failed: %d", r);
 #endif
+  }
 
   /* Publish a driver up event. */
   if ((r = ds_retrieve_label_name(label, getprocnr())) != OK)