Revert "ocfs2: mount shared volume without ha stack"

This reverts commit 912f655d.

This commit introduced a regression that can cause mount hung.  The
changes in __ocfs2_find_empty_slot causes that any node with none-zero
node number can grab the slot that was already taken by node 0, so node 1
will access the same journal with node 0, when it try to grab journal
cluster lock, it will hung because it was already acquired by node 0. 
It's very easy to reproduce this, in one cluster, mount node 0 first, then
node 1, you will see the following call trace from node 1.

[13148.735424] INFO: task mount.ocfs2:53045 blocked for more than 122 seconds.
[13148.739691]       Not tainted 5.15.0-2148.0.4.el8uek.mountracev2.x86_64 #2
[13148.742560] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[13148.745846] task:mount.ocfs2     state:D stack:    0 pid:53045 ppid: 53044 flags:0x00004000
[13148.749354] Call Trace:
[13148.750718]  <TASK>
[13148.752019]  ? usleep_range+0x90/0x89
[13148.753882]  __schedule+0x210/0x567
[13148.755684]  schedule+0x44/0xa8
[13148.757270]  schedule_timeout+0x106/0x13c
[13148.759273]  ? __prepare_to_swait+0x53/0x78
[13148.761218]  __wait_for_common+0xae/0x163
[13148.763144]  __ocfs2_cluster_lock.constprop.0+0x1d6/0x870 [ocfs2]
[13148.765780]  ? ocfs2_inode_lock_full_nested+0x18d/0x398 [ocfs2]
[13148.768312]  ocfs2_inode_lock_full_nested+0x18d/0x398 [ocfs2]
[13148.770968]  ocfs2_journal_init+0x91/0x340 [ocfs2]
[13148.773202]  ocfs2_check_volume+0x39/0x461 [ocfs2]
[13148.775401]  ? iput+0x69/0xba
[13148.777047]  ocfs2_mount_volume.isra.0.cold+0x40/0x1f5 [ocfs2]
[13148.779646]  ocfs2_fill_super+0x54b/0x853 [ocfs2]
[13148.781756]  mount_bdev+0x190/0x1b7
[13148.783443]  ? ocfs2_remount+0x440/0x440 [ocfs2]
[13148.785634]  legacy_get_tree+0x27/0x48
[13148.787466]  vfs_get_tree+0x25/0xd0
[13148.789270]  do_new_mount+0x18c/0x2d9
[13148.791046]  __x64_sys_mount+0x10e/0x142
[13148.792911]  do_syscall_64+0x3b/0x89
[13148.794667]  entry_SYSCALL_64_after_hwframe+0x170/0x0
[13148.797051] RIP: 0033:0x7f2309f6e26e
[13148.798784] RSP: 002b:00007ffdcee7d408 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
[13148.801974] RAX: ffffffffffffffda RBX: 00007ffdcee7d4a0 RCX: 00007f2309f6e26e
[13148.804815] RDX: 0000559aa762a8ae RSI: 0000559aa939d340 RDI: 0000559aa93a22b0
[13148.807719] RBP: 00007ffdcee7d5b0 R08: 0000559aa93a2290 R09: 00007f230a0b4820
[13148.810659] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffdcee7d420
[13148.813609] R13: 0000000000000000 R14: 0000559aa939f000 R15: 0000000000000000
[13148.816564]  </TASK>

To fix it, we can just fix __ocfs2_find_empty_slot.  But original commit
introduced the feature to mount ocfs2 locally even it is cluster based,
that is a very dangerous, it can easily cause serious data corruption,
there is no way to stop other nodes mounting the fs and corrupting it. 
Setup ha or other cluster-aware stack is just the cost that we have to
take for avoiding corruption, otherwise we have to do it in kernel.

Link: https://lkml.kernel.org/r/20220603222801.42488-1-junxiao.bi@oracle.com
Fixes: 912f655d("ocfs2: mount shared volume without ha stack")
Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Cc: <heming.zhao@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/ocfs2/ocfs2.h

@@ -277,7 +277,6 @@ enum ocfs2_mount_options
 	OCFS2_MOUNT_JOURNAL_ASYNC_COMMIT = 1 << 15,  /* Journal Async Commit */
 	OCFS2_MOUNT_ERRORS_CONT = 1 << 16, /* Return EIO to the calling process on error */
 	OCFS2_MOUNT_ERRORS_ROFS = 1 << 17, /* Change filesystem to read-only on error */
-	OCFS2_MOUNT_NOCLUSTER = 1 << 18, /* No cluster aware filesystem mount */
 };
 
 #define OCFS2_OSB_SOFT_RO	0x0001
@@ -673,8 +672,7 @@ static inline int ocfs2_cluster_o2cb_global_heartbeat(struct ocfs2_super *osb)
 
 static inline int ocfs2_mount_local(struct ocfs2_super *osb)
 {
-	return ((osb->s_feature_incompat & OCFS2_FEATURE_INCOMPAT_LOCAL_MOUNT)
-		|| (osb->s_mount_opt & OCFS2_MOUNT_NOCLUSTER));
+	return (osb->s_feature_incompat & OCFS2_FEATURE_INCOMPAT_LOCAL_MOUNT);
 }
 
 static inline int ocfs2_uses_extended_slot_map(struct ocfs2_super *osb)

fs/ocfs2/slot_map.c

@@ -252,16 +252,14 @@ static int __ocfs2_find_empty_slot(struct ocfs2_slot_info *si,
 	int i, ret = -ENOSPC;
 
 	if ((preferred >= 0) && (preferred < si->si_num_slots)) {
-		if (!si->si_slots[preferred].sl_valid ||
-		    !si->si_slots[preferred].sl_node_num) {
+		if (!si->si_slots[preferred].sl_valid) {
 			ret = preferred;
 			goto out;
 		}
 	}
 
 	for(i = 0; i < si->si_num_slots; i++) {
-		if (!si->si_slots[i].sl_valid ||
-		    !si->si_slots[i].sl_node_num) {
+		if (!si->si_slots[i].sl_valid) {
 			ret = i;
 			break;
 		}
@@ -456,10 +454,6 @@ int ocfs2_find_slot(struct ocfs2_super *osb)
 	spin_lock(&osb->osb_lock);
 	ocfs2_update_slot_info(si);
 
-	if (ocfs2_mount_local(osb))
-		/* use slot 0 directly in local mode */
-		slot = 0;
-	else {
 	/* search for ourselves first and take the slot if it already
 	 * exists. Perhaps we need to mark this in a variable for our
 	 * own journal recovery? Possibly not, though we certainly
@@ -476,10 +470,8 @@ int ocfs2_find_slot(struct ocfs2_super *osb)
 			goto bail;
 		}
 	} else
-			printk(KERN_INFO "ocfs2: Slot %d on device (%s) was "
-			       "already allocated to this node!\n",
-			       slot, osb->dev_str);
-	}
+		printk(KERN_INFO "ocfs2: Slot %d on device (%s) was already "
+		       "allocated to this node!\n", slot, osb->dev_str);
 
 	ocfs2_set_slot(si, slot, osb->node_num);
 	osb->slot_num = slot;

fs/ocfs2/super.c

@@ -172,7 +172,6 @@ enum {
 	Opt_dir_resv_level,
 	Opt_journal_async_commit,
 	Opt_err_cont,
-	Opt_nocluster,
 	Opt_err,
 };
 
@@ -206,7 +205,6 @@ static const match_table_t tokens = {
 	{Opt_dir_resv_level, "dir_resv_level=%u"},
 	{Opt_journal_async_commit, "journal_async_commit"},
 	{Opt_err_cont, "errors=continue"},
-	{Opt_nocluster, "nocluster"},
 	{Opt_err, NULL}
 };
 
@@ -618,13 +616,6 @@ static int ocfs2_remount(struct super_block *sb, int *flags, char *data)
 		goto out;
 	}
 
-	tmp = OCFS2_MOUNT_NOCLUSTER;
-	if ((osb->s_mount_opt & tmp) != (parsed_options.mount_opt & tmp)) {
-		ret = -EINVAL;
-		mlog(ML_ERROR, "Cannot change nocluster option on remount\n");
-		goto out;
-	}
-
 	tmp = OCFS2_MOUNT_HB_LOCAL | OCFS2_MOUNT_HB_GLOBAL |
 		OCFS2_MOUNT_HB_NONE;
 	if ((osb->s_mount_opt & tmp) != (parsed_options.mount_opt & tmp)) {
@@ -865,7 +856,6 @@ static int ocfs2_verify_userspace_stack(struct ocfs2_super *osb,
 	}
 
 	if (ocfs2_userspace_stack(osb) &&
-	    !(osb->s_mount_opt & OCFS2_MOUNT_NOCLUSTER) &&
 	    strncmp(osb->osb_cluster_stack, mopt->cluster_stack,
 		    OCFS2_STACK_LABEL_LEN)) {
 		mlog(ML_ERROR,
@@ -1137,11 +1127,6 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
 	       osb->s_mount_opt & OCFS2_MOUNT_DATA_WRITEBACK ? "writeback" :
 	       "ordered");
 
-	if ((osb->s_mount_opt & OCFS2_MOUNT_NOCLUSTER) &&
-	   !(osb->s_feature_incompat & OCFS2_FEATURE_INCOMPAT_LOCAL_MOUNT))
-		printk(KERN_NOTICE "ocfs2: The shared device (%s) is mounted "
-		       "without cluster aware mode.\n", osb->dev_str);
-
 	atomic_set(&osb->vol_state, VOLUME_MOUNTED);
 	wake_up(&osb->osb_mount_event);
 
@@ -1452,9 +1437,6 @@ static int ocfs2_parse_options(struct super_block *sb,
 		case Opt_journal_async_commit:
 			mopt->mount_opt |= OCFS2_MOUNT_JOURNAL_ASYNC_COMMIT;
 			break;
-		case Opt_nocluster:
-			mopt->mount_opt |= OCFS2_MOUNT_NOCLUSTER;
-			break;
 		default:
 			mlog(ML_ERROR,
 			     "Unrecognized mount option \"%s\" "
@@ -1566,9 +1548,6 @@ static int ocfs2_show_options(struct seq_file *s, struct dentry *root)
 	if (opts & OCFS2_MOUNT_JOURNAL_ASYNC_COMMIT)
 		seq_printf(s, ",journal_async_commit");
 
-	if (opts & OCFS2_MOUNT_NOCLUSTER)
-		seq_printf(s, ",nocluster");
-
 	return 0;
 }