GFS2: Add "-o errors=panic|withdraw" mount options

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).

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

4 files changed, 71 insertions, 14 deletions

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 61801ada36f0..1d11e6e0373e 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -406,6 +406,12 @@ 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 */
@@ -422,6 +428,7 @@ struct gfs2_args {
         unsigned int ar_data:2;                 /* ordered/writeback */
         unsigned int ar_meta:1;                 /* mount metafs */
         unsigned int ar_discard:1;              /* discard requests */
+        unsigned int ar_errors:2;               /* errors=withdraw | panic */
         int ar_commit;                          /* Commit interval */
 };
 
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 39021c020176..165518a1041e 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1168,6 +1168,7 @@ 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_commit = 60;
+        sdp->sd_args.ar_errors = GFS2_ERRORS_DEFAULT;
 
         error = gfs2_mount_args(sdp, &sdp->sd_args, data);
         if (error) {
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index 85bd2bc8c1de..7a5c128e8776 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -68,6 +68,8 @@ enum {
         Opt_discard,
         Opt_nodiscard,
         Opt_commit,
+        Opt_err_withdraw,
+        Opt_err_panic,
         Opt_error,
 };
 
@@ -97,6 +99,8 @@ static const match_table_t tokens = {
         {Opt_discard, "discard"},
         {Opt_nodiscard, "nodiscard"},
         {Opt_commit, "commit=%d"},
+        {Opt_err_withdraw, "errors=withdraw"},
+        {Opt_err_panic, "errors=panic"},
         {Opt_error, NULL}
 };
 
@@ -152,6 +156,11 @@ 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) {
+                                fs_info(sdp, "-o debug and -o errors=panic "
+                                       "are mutually exclusive.\n");
+                                return -EINVAL;
+                        }
                         args->ar_debug = 1;
                         break;
                 case Opt_nodebug:
@@ -205,6 +214,17 @@ int gfs2_mount_args(struct gfs2_sbd *sdp, struct gfs2_args *args, char *options)
                                 return rv ? rv : -EINVAL;
                         }
                         break;
+                case Opt_err_withdraw:
+                        args->ar_errors = GFS2_ERRORS_WITHDRAW;
+                        break;
+                case Opt_err_panic:
+                        if (args->ar_debug) {
+                                fs_info(sdp, "-o debug and -o errors=panic "
+                                        "are mutually exclusive.\n");
+                                return -EINVAL;
+                        }
+                        args->ar_errors = GFS2_ERRORS_PANIC;
+                        break;
                 case Opt_error:
                 default:
                         fs_info(sdp, "invalid mount option: %s\n", o);
@@ -1226,6 +1246,22 @@ static int gfs2_show_options(struct seq_file *s, struct vfsmount *mnt)
         lfsecs = sdp->sd_tune.gt_log_flush_secs;
         if (lfsecs != 60)
                 seq_printf(s, ",commit=%d", lfsecs);
+        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 9d12b1118ba0..f6a7efa34eb9 100644
--- a/fs/gfs2/util.c
+++ b/fs/gfs2/util.c
@@ -38,24 +38,30 @@ int gfs2_lm_withdraw(struct gfs2_sbd *sdp, char *fmt, ...)
         const struct lm_lockops *lm = ls->ls_ops;
         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);
 
-        kobject_uevent(&sdp->sd_kobj, KOBJ_OFFLINE);
+                kobject_uevent(&sdp->sd_kobj, KOBJ_OFFLINE);
 
-        if (lm->lm_unmount) {
-                fs_err(sdp, "telling LM to unmount\n");
-                lm->lm_unmount(sdp);
+                if (lm->lm_unmount) {
+                        fs_err(sdp, "telling LM to unmount\n");
+                        lm->lm_unmount(sdp);
+                }
+                fs_err(sdp, "withdrawn\n");
+                dump_stack();
         }
-        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;
 }
@@ -93,17 +99,24 @@ 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;