[Ocfs2-devel] About Mark's advice on bug 48
Sonic Zhang
sonic.zhang at intel.com
Fri Mar 26 15:27:07 CST 2004
Hi Mark,
Finally, I found the second halt is caused by starvation when routine
ocfs_joutnal_set_unmounted() acquiring the lock osb->publish_lock. In
thread ocfs_volume_thread(), the delta jiffies to sleep between up() and
down() in schedule_timeout() is too short. Routine
ocfs_joutnal_set_unmounted() has no chance to check if lock
osb->publish_lock is released between it is releases and reacquired by
thread ocfs_volume_thread. So routine ocfs_journal_set_unmounted()
always waits in loop. After I change the delta jiffies from 50 to 500,
kernel 2.6 won't halt when it reboots after a OCFS volume is mounted.
I also add a line to release the lock in a branch to symbol "finally".
This may remove latent dead lock. In addition, I clear the reference
point OcfsIpcCtxt.task before thread ocfs_recv_thread() exits. This
prevents invalid access to the task structure in routine
ocfs_dismount_volume() when rebooting.
Here is my patch to file nm.c.
-------------------------------------------------------------------
--- ocfs2.old/src/nm.c.old 2004-03-26 15:21:32.000000000 +0800
+++ ocfs2/src/nm.c 2004-03-26 15:21:06.000000000 +0800
@@ -119,6 +119,8 @@
OcfsIpcCtxt.recv_sock = NULL;
}
+ OcfsIpcCtxt.task = NULL;
+
/* signal main thread of ipcdlm's exit */
complete (&(OcfsIpcCtxt.complete));
@@ -227,6 +229,12 @@
//#define OCFS_BH_SEM_PRUNE_LIMIT 60 // prune everything each 30
seconds
#define OCFS_BH_SEM_PRUNE_LIMIT 60000 // 8 hours :)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+#define OCFS_SCHEDULE_TIMEOUT_JIFFIES 500
+#else
+#define OCFS_SCHEDULE_TIMEOUT_JIFFIES 50
+#endif
+
/*
* ocfs_volume_thread()
*
@@ -409,6 +417,7 @@
OCFS_BH_PUT_DATA(bh);
status = ocfs_write_bh(osb, bh, 0, NULL);
if (status < 0) {
+ up(&(osb->publish_lock));
LOG_ERROR_STATUS (status);
goto finally;
}
@@ -425,7 +434,7 @@
goto finally;
}
}
- osb->hbt = 50 + jiffies;
+ osb->hbt = OCFS_SCHEDULE_TIMEOUT_JIFFIES + jiffies;
finally:
status = 0;
@@ -435,7 +444,7 @@
break;
j = jiffies;
if (time_after (j, (unsigned long) (osb->hbt))) {
- osb->hbt = 50 + j;
+ osb->hbt = OCFS_SCHEDULE_TIMEOUT_JIFFIES + j;
}
set_current_state (TASK_INTERRUPTIBLE);
schedule_timeout (osb->hbt - j);
More information about the Ocfs2-devel
mailing list