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Date:      Thu, 8 Sep 2011 12:56:26 +0000 (UTC)
From:      Attilio Rao <attilio@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r225448 - in head/sys: conf kern sys
Message-ID:  <201109081256.p88CuQHi091681@svn.freebsd.org>
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Author: attilio
Date: Thu Sep  8 12:56:26 2011
New Revision: 225448
URL: http://svn.freebsd.org/changeset/base/225448

Log:
  Improve the informations reported in case of busy buffers during the shutdown:
  - Axe out the SHOW_BUSYBUFS option and uses a tunable for selectively
  enable/disable it, which is defaulted for not printing anything (0
  value) but can be changed for printing (1 value) and be verbose (2
  value)
  - Improves the informations outputed: right now, there is no track of
  the actual struct buf object or vnode which are referenced by the
  shutdown process, but it is printed the related struct bufobj object
  which is not really helpful
  - Add more verbosity about the state of the struct buf lock and the
  vnode informations, with the latter to be activated separately by the
  sysctl
  
  Sponsored by:	Sandvine Incorporated
  Reviewed by:	emaste, kib
  Approved by:	re (ksmith)
  MFC after:	10 days

Modified:
  head/sys/conf/NOTES
  head/sys/conf/options
  head/sys/kern/kern_shutdown.c
  head/sys/kern/vfs_bio.c
  head/sys/sys/buf.h

Modified: head/sys/conf/NOTES
==============================================================================
--- head/sys/conf/NOTES	Thu Sep  8 12:19:58 2011	(r225447)
+++ head/sys/conf/NOTES	Thu Sep  8 12:56:26 2011	(r225448)
@@ -2929,7 +2929,6 @@ options 	SCSI_NCR_MYADDR=7
 options 	SC_DEBUG_LEVEL=5	# Syscons debug level
 options 	SC_RENDER_DEBUG	# syscons rendering debugging
 
-options 	SHOW_BUSYBUFS	# List buffers that prevent root unmount
 options 	VFS_BIO_DEBUG	# VFS buffer I/O debugging
 
 options 	KSTACK_MAX_PAGES=32 # Maximum pages to give the kernel stack

Modified: head/sys/conf/options
==============================================================================
--- head/sys/conf/options	Thu Sep  8 12:19:58 2011	(r225447)
+++ head/sys/conf/options	Thu Sep  8 12:56:26 2011	(r225448)
@@ -156,7 +156,6 @@ QUOTA
 SCHED_4BSD	opt_sched.h
 SCHED_STATS	opt_sched.h
 SCHED_ULE	opt_sched.h
-SHOW_BUSYBUFS
 SLEEPQUEUE_PROFILING
 SLHCI_DEBUG	opt_slhci.h
 SPX_HACK

Modified: head/sys/kern/kern_shutdown.c
==============================================================================
--- head/sys/kern/kern_shutdown.c	Thu Sep  8 12:19:58 2011	(r225447)
+++ head/sys/kern/kern_shutdown.c	Thu Sep  8 12:56:26 2011	(r225448)
@@ -40,7 +40,6 @@ __FBSDID("$FreeBSD$");
 #include "opt_ddb.h"
 #include "opt_kdb.h"
 #include "opt_panic.h"
-#include "opt_show_busybufs.h"
 #include "opt_sched.h"
 #include "opt_watchdog.h"
 
@@ -66,6 +65,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/smp.h>
 #include <sys/sysctl.h>
 #include <sys/sysproto.h>
+#include <sys/vnode.h>
 #ifdef SW_WATCHDOG
 #include <sys/watchdog.h>
 #endif
@@ -123,6 +123,14 @@ TUNABLE_INT("kern.sync_on_panic", &sync_
 
 SYSCTL_NODE(_kern, OID_AUTO, shutdown, CTLFLAG_RW, 0, "Shutdown environment");
 
+#ifndef DIAGNOSTIC
+static int show_busybufs;
+#else
+static int show_busybufs = 1;
+#endif
+SYSCTL_INT(_kern_shutdown, OID_AUTO, show_busybufs, CTLFLAG_RW,
+	&show_busybufs, 0, "");
+
 /*
  * Variable panicstr contains argument to first call to panic; used as flag
  * to indicate that the kernel has already called panic.
@@ -389,13 +397,17 @@ kern_reboot(int howto)
 				}
 #endif
 				nbusy++;
-#if defined(SHOW_BUSYBUFS) || defined(DIAGNOSTIC)
-				printf(
-			    "%d: bufobj:%p, flags:%0x, blkno:%ld, lblkno:%ld\n",
-				    nbusy, bp->b_bufobj,
-				    bp->b_flags, (long)bp->b_blkno,
-				    (long)bp->b_lblkno);
-#endif
+				if (show_busybufs > 0) {
+					printf(
+	    "%d: buf:%p, vnode:%p, flags:%0x, blkno:%jd, lblkno:%jd, buflock:",
+					    nbusy, bp, bp->b_vp, bp->b_flags,
+					    (intmax_t)bp->b_blkno,
+					    (intmax_t)bp->b_lblkno);
+					BUF_LOCKPRINTINFO(bp);
+					if (show_busybufs > 1)
+						vn_printf(bp->b_vp,
+						    "vnode content: ");
+				}
 			}
 		}
 		if (nbusy) {

Modified: head/sys/kern/vfs_bio.c
==============================================================================
--- head/sys/kern/vfs_bio.c	Thu Sep  8 12:19:58 2011	(r225447)
+++ head/sys/kern/vfs_bio.c	Thu Sep  8 12:56:26 2011	(r225448)
@@ -4020,7 +4020,7 @@ DB_SHOW_COMMAND(buffer, db_show_buffer)
 		db_printf("\n");
 	}
 	db_printf(" ");
-	lockmgr_printinfo(&bp->b_lock);
+	BUF_LOCKPRINTINFO(bp);
 }
 
 DB_SHOW_COMMAND(lockedbufs, lockedbufs)

Modified: head/sys/sys/buf.h
==============================================================================
--- head/sys/sys/buf.h	Thu Sep  8 12:19:58 2011	(r225447)
+++ head/sys/sys/buf.h	Thu Sep  8 12:56:26 2011	(r225448)
@@ -311,6 +311,12 @@ extern const char *buf_wmesg;		/* Defaul
 	lockdestroy(&(bp)->b_lock)
 
 /*
+ * Print informations on a buffer lock.
+ */
+#define BUF_LOCKPRINTINFO(bp) 						\
+	lockmgr_printinfo(&(bp)->b_lock)
+
+/*
  * Buffer lock assertions.
  */
 #if defined(INVARIANTS) && defined(INVARIANT_SUPPORT)

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