nilfs2: add norecovery mount option

This adds "norecovery" mount option which disables temporal write access to read-only mounts or snapshots during mount/recovery. Without this option, write access will be even performed for those types of mounts; the temporal write access is needed to mount root file system read-only after an unclean shutdown. This option will be helpful when user wants to prevent any write access to the device. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Cc: Eric Sandeen <sandeen@redhat.com>

nilfs2: add norecovery mount option
This adds "norecovery" mount option which disables temporal write access to read-only mounts or snapshots during mount/recovery. Without this option, write access will be even performed for those types of mounts; the temporal write access is needed to mount root file system read-only after an unclean shutdown. This option will be helpful when user wants to prevent any write access to the device. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Cc: Eric Sandeen <sandeen@redhat.com>
Ryusuke Konishi
1 parent a057d2c011
Showing 4 changed files with 39 additions and 3 deletions Side-by-side Diff
Documentation/filesystems/nilfs2.txt
fs/nilfs2/super.c
fs/nilfs2/the_nilfs.c
include/linux/nilfs2_fs.h
@@ -70,6 +70,10 @@
 			blocks.  That means, it is guaranteed that no
 			overtaking of events occurs in the recovered file
 			system after a crash.
+norecovery		Disable recovery of the filesystem on mount.
+			This disables every write access on the device for
+			read-only mounts or snapshots.  This option will fail
+			for r/w mounts on an unclean volume.
  
 NILFS2 usage
 ============
@@ -479,6 +479,8 @@
 		seq_printf(seq, ",errors=panic");
 	if (nilfs_test_opt(sbi, STRICT_ORDER))
 		seq_printf(seq, ",order=strict");
+	if (nilfs_test_opt(sbi, NORECOVERY))
+		seq_printf(seq, ",norecovery");
  
 	return 0;
 }
@@ -547,7 +549,7 @@
  
 enum {
 	Opt_err_cont, Opt_err_panic, Opt_err_ro,
-	Opt_nobarrier, Opt_snapshot, Opt_order,
+	Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
 	Opt_err,
 };
  
@@ -558,6 +560,7 @@
 	{Opt_nobarrier, "nobarrier"},
 	{Opt_snapshot, "cp=%u"},
 	{Opt_order, "order=%s"},
+	{Opt_norecovery, "norecovery"},
 	{Opt_err, NULL}
 };
  
@@ -608,6 +611,9 @@
 			sbi->s_snapshot_cno = option;
 			nilfs_set_opt(sbi, SNAPSHOT);
 			break;
+		case Opt_norecovery:
+			nilfs_set_opt(sbi, NORECOVERY);
+			break;
 		default:
 			printk(KERN_ERR
 			       "NILFS: Unrecognized mount option \"%s\"\n", p);
@@ -859,6 +865,14 @@
 		printk(KERN_WARNING "NILFS (device %s): couldn't "
 		       "remount to a different snapshot. \n",
 		       sb->s_id);
+		err = -EINVAL;
+		goto restore_opts;
+	}
+
+	if (!nilfs_valid_fs(nilfs)) {
+		printk(KERN_WARNING "NILFS (device %s): couldn't "
+		       "remount because the filesystem is in an "
+		       "incomplete recovery state.\n", sb->s_id);
 		err = -EINVAL;
 		goto restore_opts;
 	}
@@ -264,8 +264,14 @@
 	int valid_fs = nilfs_valid_fs(nilfs);
 	int err;
  
-	if (nilfs_loaded(nilfs))
-		return 0;
+	if (nilfs_loaded(nilfs)) {
+		if (valid_fs ||
+		    ((s_flags & MS_RDONLY) && nilfs_test_opt(sbi, NORECOVERY)))
+			return 0;
+		printk(KERN_ERR "NILFS: the filesystem is in an incomplete "
+		       "recovery state.\n");
+		return -EINVAL;
+	}
  
 	if (!valid_fs) {
 		printk(KERN_WARNING "NILFS warning: mounting unchecked fs\n");
@@ -295,6 +301,11 @@
 		goto skip_recovery;
  
 	if (s_flags & MS_RDONLY) {
+		if (nilfs_test_opt(sbi, NORECOVERY)) {
+			printk(KERN_INFO "NILFS: norecovery option specified. "
+			       "skipping roll-forward recovery\n");
+			goto skip_recovery;
+		}
 		if (really_read_only) {
 			printk(KERN_ERR "NILFS: write access "
 			       "unavailable, cannot proceed.\n");
@@ -302,6 +313,11 @@
 			goto failed_unload;
 		}
 		sbi->s_super->s_flags &= ~MS_RDONLY;
+	} else if (nilfs_test_opt(sbi, NORECOVERY)) {
+		printk(KERN_ERR "NILFS: recovery cancelled because norecovery "
+		       "option was specified for a read/write mount\n");
+		err = -EINVAL;
+		goto failed_unload;
 	}
  
 	err = nilfs_recover_logical_segments(nilfs, sbi, &ri);
@@ -151,6 +151,8 @@
 #define NILFS_MOUNT_BARRIER		0x1000  /* Use block barriers */
 #define NILFS_MOUNT_STRICT_ORDER	0x2000  /* Apply strict in-order
 						   semantics also for data */
+#define NILFS_MOUNT_NORECOVERY		0x4000  /* Disable write access during
+						   mount-time recovery */
  
  
 /**
...	...	@@ -70,6 +70,10 @@
70	70	blocks. That means, it is guaranteed that no
71	71	overtaking of events occurs in the recovered file
72	72	system after a crash.
	73	+norecovery Disable recovery of the filesystem on mount.
	74	+ This disables every write access on the device for
	75	+ read-only mounts or snapshots. This option will fail
	76	+ for r/w mounts on an unclean volume.
73	77
74	78	NILFS2 usage
75	79	============
...	...	@@ -479,6 +479,8 @@
479	479	seq_printf(seq, ",errors=panic");
480	480	if (nilfs_test_opt(sbi, STRICT_ORDER))
481	481	seq_printf(seq, ",order=strict");
	482	+ if (nilfs_test_opt(sbi, NORECOVERY))
	483	+ seq_printf(seq, ",norecovery");
482	484
483	485	return 0;
484	486	}
...	...	@@ -547,7 +549,7 @@
547	549
548	550	enum {
549	551	Opt_err_cont, Opt_err_panic, Opt_err_ro,
550		- Opt_nobarrier, Opt_snapshot, Opt_order,
	552	+ Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
551	553	Opt_err,
552	554	};
553	555
...	...	@@ -558,6 +560,7 @@
558	560	{Opt_nobarrier, "nobarrier"},
559	561	{Opt_snapshot, "cp=%u"},
560	562	{Opt_order, "order=%s"},
	563	+ {Opt_norecovery, "norecovery"},
561	564	{Opt_err, NULL}
562	565	};
563	566
...	...	@@ -608,6 +611,9 @@
608	611	sbi->s_snapshot_cno = option;
609	612	nilfs_set_opt(sbi, SNAPSHOT);
610	613	break;
	614	+ case Opt_norecovery:
	615	+ nilfs_set_opt(sbi, NORECOVERY);
	616	+ break;
611	617	default:
612	618	printk(KERN_ERR
613	619	"NILFS: Unrecognized mount option \"%s\"\n", p);
...	...	@@ -859,6 +865,14 @@
859	865	printk(KERN_WARNING "NILFS (device %s): couldn't "
860	866	"remount to a different snapshot. \n",
861	867	sb->s_id);
	868	+ err = -EINVAL;
	869	+ goto restore_opts;
	870	+ }
	871	+
	872	+ if (!nilfs_valid_fs(nilfs)) {
	873	+ printk(KERN_WARNING "NILFS (device %s): couldn't "
	874	+ "remount because the filesystem is in an "
	875	+ "incomplete recovery state.\n", sb->s_id);
862	876	err = -EINVAL;
863	877	goto restore_opts;
864	878	}
...	...	@@ -264,8 +264,14 @@
264	264	int valid_fs = nilfs_valid_fs(nilfs);
265	265	int err;
266	266
267		- if (nilfs_loaded(nilfs))
268		- return 0;
	267	+ if (nilfs_loaded(nilfs)) {
	268	+ if (valid_fs \|\|
	269	+ ((s_flags & MS_RDONLY) && nilfs_test_opt(sbi, NORECOVERY)))
	270	+ return 0;
	271	+ printk(KERN_ERR "NILFS: the filesystem is in an incomplete "
	272	+ "recovery state.\n");
	273	+ return -EINVAL;
	274	+ }
269	275
270	276	if (!valid_fs) {
271	277	printk(KERN_WARNING "NILFS warning: mounting unchecked fs\n");
...	...	@@ -295,6 +301,11 @@
295	301	goto skip_recovery;
296	302
297	303	if (s_flags & MS_RDONLY) {
	304	+ if (nilfs_test_opt(sbi, NORECOVERY)) {
	305	+ printk(KERN_INFO "NILFS: norecovery option specified. "
	306	+ "skipping roll-forward recovery\n");
	307	+ goto skip_recovery;
	308	+ }
298	309	if (really_read_only) {
299	310	printk(KERN_ERR "NILFS: write access "
300	311	"unavailable, cannot proceed.\n");
...	...	@@ -302,6 +313,11 @@
302	313	goto failed_unload;
303	314	}
304	315	sbi->s_super->s_flags &= ~MS_RDONLY;
	316	+ } else if (nilfs_test_opt(sbi, NORECOVERY)) {
	317	+ printk(KERN_ERR "NILFS: recovery cancelled because norecovery "
	318	+ "option was specified for a read/write mount\n");
	319	+ err = -EINVAL;
	320	+ goto failed_unload;
305	321	}
306	322
307	323	err = nilfs_recover_logical_segments(nilfs, sbi, &ri);
...	...	@@ -151,6 +151,8 @@
151	151	#define NILFS_MOUNT_BARRIER 0x1000 /* Use block barriers */
152	152	#define NILFS_MOUNT_STRICT_ORDER 0x2000 /* Apply strict in-order
153	153	semantics also for data */
	154	+#define NILFS_MOUNT_NORECOVERY 0x4000 /* Disable write access during
	155	+ mount-time recovery */
154	156
155	157
156	158	/**