From: Bob Peterson <rpeterso@redhat.com>
Date: Fri, 2 Oct 2009 15:50:09 -0400
Subject: [gfs2] mount option: -o errors=withdraw|panic
Message-id: 948278168.1019551254513009051.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com
O-Subject: [RHEL5.5 PATCH] [GFS2] bz518106 - [RFE] GFS2: New mount option: -o errors=withdraw|panic
Bugzilla: 518106
RH-Acked-by: Steven Whitehouse <swhiteho@redhat.com>

Hi,

This patch adds "-o errors=panic" and "-o errors=withdraw" to the
gfs2 mount options.  The "errors=withdraw" option is today's
current behaviour, meaning to withdraw from the file system if a
non-serious gfs2 error occurs.  The new "errors=panic" option
tells gfs2 to force a kernel panic if a non-serious gfs2 file
system error occurs.  This may be useful, for example, where
fabric-level fencing is used that has no way to reboot (such as
fence_scsi).

This patch is for rhbz#518106.  It was tested on system roth-01
and found to be correct.  A corresponding patch is already in
the upstream repo for gfs2.

Regards,

Bob Peterson
Red Hat GFS

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
--
 fs/gfs2/incore.h     |    7 +++++++
 fs/gfs2/lm.c         |   18 ++++++++++++------
 fs/gfs2/mount.c      |   20 ++++++++++++++++++++
 fs/gfs2/ops_fstype.c |    1 +
 fs/gfs2/ops_super.c  |   16 ++++++++++++++++
 fs/gfs2/util.c       |   17 ++++++++++++-----
 6 files changed, 68 insertions(+), 11 deletions(-)

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index ee47840..0083d92 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -377,6 +377,12 @@ struct gfs2_statfs_change_host {
 #define GFS2_DATA_WRITEBACK	1
 #define GFS2_DATA_ORDERED	2
 
+#define GFS2_ERRORS_DEFAULT     GFS2_ERRORS_WITHDRAW
+#define GFS2_ERRORS_WITHDRAW    0
+#define GFS2_ERRORS_CONTINUE    1 /* place holder for future feature */
+#define GFS2_ERRORS_RO          2 /* place holder for future feature */
+#define GFS2_ERRORS_PANIC       3
+
 struct gfs2_args {
 	char ar_lockproto[GFS2_LOCKNAME_LEN]; /* Name of the Lock Protocol */
 	char ar_locktable[GFS2_LOCKNAME_LEN]; /* Name of the Lock Table */
@@ -393,6 +399,7 @@ struct gfs2_args {
 	int ar_suiddir; /* suiddir support */
 	int ar_data; /* ordered/writeback */
 	int ar_meta; /* mount metafs */
+	int ar_errors; /* errors=panic|withdraw */
 };
 
 struct gfs2_tune {
diff --git a/fs/gfs2/lm.c b/fs/gfs2/lm.c
index cfcc39b..4152e7a 100644
--- a/fs/gfs2/lm.c
+++ b/fs/gfs2/lm.c
@@ -96,21 +96,27 @@ int gfs2_lm_withdraw(struct gfs2_sbd *sdp, char *fmt, ...)
 {
 	va_list args;
 
-	if (test_and_set_bit(SDF_SHUTDOWN, &sdp->sd_flags))
+	if (sdp->sd_args.ar_errors == GFS2_ERRORS_WITHDRAW &&
+	    test_and_set_bit(SDF_SHUTDOWN, &sdp->sd_flags))
 		return 0;
 
 	va_start(args, fmt);
 	vprintk(fmt, args);
 	va_end(args);
 
-	fs_err(sdp, "about to withdraw this file system\n");
-	BUG_ON(sdp->sd_args.ar_debug);
+	if (sdp->sd_args.ar_errors == GFS2_ERRORS_WITHDRAW) {
+		fs_err(sdp, "about to withdraw this file system\n");
+		BUG_ON(sdp->sd_args.ar_debug);
 
-	fs_err(sdp, "telling LM to withdraw\n");
-	gfs2_withdraw_lockproto(&sdp->sd_lockstruct);
-	fs_err(sdp, "withdrawn\n");
+		fs_err(sdp, "telling LM to withdraw\n");
+		gfs2_withdraw_lockproto(&sdp->sd_lockstruct);
+		fs_err(sdp, "withdrawn\n");
+	}
 	dump_stack();
 
+	if (sdp->sd_args.ar_errors == GFS2_ERRORS_PANIC)
+		panic("GFS2: fsid=%s: panic requested.\n", sdp->sd_fsname);
+
 	return -1;
 }
 
diff --git a/fs/gfs2/mount.c b/fs/gfs2/mount.c
index 5af3e97..88679ba 100644
--- a/fs/gfs2/mount.c
+++ b/fs/gfs2/mount.c
@@ -45,6 +45,8 @@ enum {
 	Opt_data_writeback,
 	Opt_data_ordered,
 	Opt_meta,
+	Opt_err_withdraw,
+	Opt_err_panic,
 	Opt_err,
 };
 
@@ -72,6 +74,8 @@ static match_table_t tokens = {
 	{Opt_data_writeback, "data=writeback"},
 	{Opt_data_ordered, "data=ordered"},
 	{Opt_meta, "meta"},
+	{Opt_err_withdraw, "errors=withdraw"},
+	{Opt_err_panic, "errors=panic"},
 	{Opt_err, NULL}
 };
 
@@ -126,6 +130,11 @@ int gfs2_mount_args(struct gfs2_sbd *sdp, struct gfs2_args *args, char *options)
 			args->ar_localcaching = 1;
 			break;
 		case Opt_debug:
+			if (args->ar_errors == GFS2_ERRORS_PANIC) {
+				printk(KERN_WARNING "GFS2: -o debug and -o errors=panic "
+				       "are mutually exclusive.\n");
+				return -EINVAL;
+			}
 			args->ar_debug = 1;
 			break;
 		case Opt_nodebug:
@@ -168,6 +177,17 @@ int gfs2_mount_args(struct gfs2_sbd *sdp, struct gfs2_args *args, char *options)
 		case Opt_meta:
 			args->ar_meta = 1;
 			break;
+		case Opt_err_withdraw:
+			args->ar_errors = GFS2_ERRORS_WITHDRAW;
+			break;
+		case Opt_err_panic:
+			if (args->ar_debug) {
+				printk(KERN_WARNING "GFS2: -o debug and -o errors=panic "
+					"are mutually exclusive.\n");
+				return -EINVAL;
+			}
+			args->ar_errors = GFS2_ERRORS_PANIC;
+			break;
 		case Opt_err:
 		default:
 			fs_info(sdp, "invalid mount option: %s\n", o);
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index b0e9fea..17a2914 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -985,6 +985,7 @@ static int fill_super(struct super_block *sb, void *data, int silent)
 
 	sdp->sd_args.ar_quota = GFS2_QUOTA_DEFAULT;
 	sdp->sd_args.ar_data = GFS2_DATA_DEFAULT;
+	sdp->sd_args.ar_errors = GFS2_ERRORS_DEFAULT;
 
 	error = gfs2_mount_args(sdp, &sdp->sd_args, data);
 	if (error) {
diff --git a/fs/gfs2/ops_super.c b/fs/gfs2/ops_super.c
index 15d62e4..7aec6d7 100644
--- a/fs/gfs2/ops_super.c
+++ b/fs/gfs2/ops_super.c
@@ -480,6 +480,22 @@ static int gfs2_show_options(struct seq_file *s, struct vfsmount *mnt)
 		}
 		seq_printf(s, ",data=%s", state);
 	}
+	if (args->ar_errors != GFS2_ERRORS_DEFAULT) {
+		const char *state;
+
+		switch (args->ar_errors) {
+		case GFS2_ERRORS_WITHDRAW:
+			state = "withdraw";
+			break;
+		case GFS2_ERRORS_PANIC:
+			state = "panic";
+			break;
+		default:
+			state = "unknown";
+			break;
+		}
+		seq_printf(s, ",errors=%s", state);
+	}
 
 	return 0;
 }
diff --git a/fs/gfs2/util.c b/fs/gfs2/util.c
index 42ee47a..cd13d84 100644
--- a/fs/gfs2/util.c
+++ b/fs/gfs2/util.c
@@ -67,17 +67,24 @@ int gfs2_assert_warn_i(struct gfs2_sbd *sdp, char *assertion,
 			gfs2_tune_get(sdp, gt_complain_secs) * HZ))
 		return -2;
 
-	printk(KERN_WARNING
-	       "GFS2: fsid=%s: warning: assertion \"%s\" failed\n"
-	       "GFS2: fsid=%s:   function = %s, file = %s, line = %u\n",
-	       sdp->sd_fsname, assertion,
-	       sdp->sd_fsname, function, file, line);
+	if (sdp->sd_args.ar_errors == GFS2_ERRORS_WITHDRAW)
+		printk(KERN_WARNING
+		       "GFS2: fsid=%s: warning: assertion \"%s\" failed\n"
+		       "GFS2: fsid=%s:   function = %s, file = %s, line = %u\n",
+		       sdp->sd_fsname, assertion,
+		       sdp->sd_fsname, function, file, line);
 
 	if (sdp->sd_args.ar_debug)
 		BUG();
 	else
 		dump_stack();
 
+	if (sdp->sd_args.ar_errors == GFS2_ERRORS_PANIC)
+		panic("GFS2: fsid=%s: warning: assertion \"%s\" failed\n"
+		      "GFS2: fsid=%s:   function = %s, file = %s, line = %u\n",
+		      sdp->sd_fsname, assertion,
+		      sdp->sd_fsname, function, file, line);
+
 	sdp->sd_last_warning = jiffies;
 
 	return -1;