nilfs2: add bdev freeze/thaw support

Nilfs hasn't supported the freeze/thaw feature because it didn't work due to the peculiar design that multiple super block instances could be allocated for a device. This limitation was removed by the patch "nilfs2: do not allocate multiple super block instances for a device". So now this adds the freeze/thaw support to nilfs. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

nilfs2: add bdev freeze/thaw support
Nilfs hasn't supported the freeze/thaw feature because it didn't work due to the peculiar design that multiple super block instances could be allocated for a device. This limitation was removed by the patch "nilfs2: do not allocate multiple super block instances for a device". So now this adds the freeze/thaw support to nilfs. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Ryusuke Konishi
1 parent c05dbfc260
Showing 3 changed files with 58 additions and 4 deletions Side-by-side Diff
fs/nilfs2/ioctl.c
fs/nilfs2/segment.c
fs/nilfs2/super.c
@@ -580,6 +580,8 @@
 		goto out_free;
 	}
  
+	vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
+
 	ret = nilfs_ioctl_move_blocks(inode->i_sb, &argv[0], kbufs[0]);
 	if (ret < 0)
 		printk(KERN_ERR "NILFS: GC failed during preparation: "
@@ -191,6 +191,8 @@
 	if (ret > 0)
 		return 0;
  
+	vfs_check_frozen(sb, SB_FREEZE_WRITE);
+
 	sbi = NILFS_SB(sb);
 	nilfs = sbi->s_nilfs;
 	down_read(&nilfs->ns_segctor_sem);
@@ -73,6 +73,7 @@
 struct kmem_cache *nilfs_segbuf_cachep;
 struct kmem_cache *nilfs_btree_path_cache;
  
+static int nilfs_setup_super(struct nilfs_sb_info *sbi, int is_mount);
 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
  
 static void nilfs_set_error(struct nilfs_sb_info *sbi)
@@ -439,6 +440,36 @@
 	return err;
 }
  
+static int nilfs_freeze(struct super_block *sb)
+{
+	struct nilfs_sb_info *sbi = NILFS_SB(sb);
+	struct the_nilfs *nilfs = sbi->s_nilfs;
+	int err;
+
+	if (sb->s_flags & MS_RDONLY)
+		return 0;
+
+	/* Mark super block clean */
+	down_write(&nilfs->ns_sem);
+	err = nilfs_cleanup_super(sbi);
+	up_write(&nilfs->ns_sem);
+	return err;
+}
+
+static int nilfs_unfreeze(struct super_block *sb)
+{
+	struct nilfs_sb_info *sbi = NILFS_SB(sb);
+	struct the_nilfs *nilfs = sbi->s_nilfs;
+
+	if (sb->s_flags & MS_RDONLY)
+		return 0;
+
+	down_write(&nilfs->ns_sem);
+	nilfs_setup_super(sbi, false);
+	up_write(&nilfs->ns_sem);
+	return 0;
+}
+
 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
 	struct super_block *sb = dentry->d_sb;
@@ -523,6 +554,8 @@
 	.put_super      = nilfs_put_super,
 	/* .write_super    = nilfs_write_super, */
 	.sync_fs        = nilfs_sync_fs,
+	.freeze_fs	= nilfs_freeze,
+	.unfreeze_fs	= nilfs_unfreeze,
 	/* .write_super_lockfs */
 	/* .unlockfs */
 	.statfs         = nilfs_statfs,
@@ -626,7 +659,7 @@
 		NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
 }
  
-static int nilfs_setup_super(struct nilfs_sb_info *sbi)
+static int nilfs_setup_super(struct nilfs_sb_info *sbi, int is_mount)
 {
 	struct the_nilfs *nilfs = sbi->s_nilfs;
 	struct nilfs_super_block **sbp;
@@ -638,6 +671,9 @@
 	if (!sbp)
 		return -EIO;
  
+	if (!is_mount)
+		goto skip_mount_setup;
+
 	max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
 	mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
  
  
@@ -654,9 +690,11 @@
 		sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
  
 	sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
+	sbp[0]->s_mtime = cpu_to_le64(get_seconds());
+
+skip_mount_setup:
 	sbp[0]->s_state =
 		cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
-	sbp[0]->s_mtime = cpu_to_le64(get_seconds());
 	/* synchronize sbp[1] with sbp[0] */
 	memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 	return nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
@@ -938,7 +976,7 @@
  
 	if (!(sb->s_flags & MS_RDONLY)) {
 		down_write(&nilfs->ns_sem);
-		nilfs_setup_super(sbi);
+		nilfs_setup_super(sbi, true);
 		up_write(&nilfs->ns_sem);
 	}
  
@@ -1034,7 +1072,7 @@
 			goto restore_opts;
  
 		down_write(&nilfs->ns_sem);
-		nilfs_setup_super(sbi);
+		nilfs_setup_super(sbi, true);
 		up_write(&nilfs->ns_sem);
 	}
  out:
  
@@ -1132,7 +1170,19 @@
 		goto failed;
 	}
  
+	/*
+	 * once the super is inserted into the list by sget, s_umount
+	 * will protect the lockfs code from trying to start a snapshot
+	 * while we are mounting
+	 */
+	mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
+	if (sd.bdev->bd_fsfreeze_count > 0) {
+		mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
+		err = -EBUSY;
+		goto failed;
+	}
 	s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, sd.bdev);
+	mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
 	if (IS_ERR(s)) {
 		err = PTR_ERR(s);
 		goto failed;
...	...	@@ -580,6 +580,8 @@
580	580	goto out_free;
581	581	}
582	582
	583	+ vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
	584	+
583	585	ret = nilfs_ioctl_move_blocks(inode->i_sb, &argv[0], kbufs[0]);
584	586	if (ret < 0)
585	587	printk(KERN_ERR "NILFS: GC failed during preparation: "
...	...	@@ -191,6 +191,8 @@
191	191	if (ret > 0)
192	192	return 0;
193	193
	194	+ vfs_check_frozen(sb, SB_FREEZE_WRITE);
	195	+
194	196	sbi = NILFS_SB(sb);
195	197	nilfs = sbi->s_nilfs;
196	198	down_read(&nilfs->ns_segctor_sem);
...	...	@@ -73,6 +73,7 @@
73	73	struct kmem_cache *nilfs_segbuf_cachep;
74	74	struct kmem_cache *nilfs_btree_path_cache;
75	75
	76	+static int nilfs_setup_super(struct nilfs_sb_info *sbi, int is_mount);
76	77	static int nilfs_remount(struct super_block sb, int flags, char *data);
77	78
78	79	static void nilfs_set_error(struct nilfs_sb_info *sbi)
...	...	@@ -439,6 +440,36 @@
439	440	return err;
440	441	}
441	442
	443	+static int nilfs_freeze(struct super_block *sb)
	444	+{
	445	+ struct nilfs_sb_info *sbi = NILFS_SB(sb);
	446	+ struct the_nilfs *nilfs = sbi->s_nilfs;
	447	+ int err;
	448	+
	449	+ if (sb->s_flags & MS_RDONLY)
	450	+ return 0;
	451	+
	452	+ /* Mark super block clean */
	453	+ down_write(&nilfs->ns_sem);
	454	+ err = nilfs_cleanup_super(sbi);
	455	+ up_write(&nilfs->ns_sem);
	456	+ return err;
	457	+}
	458	+
	459	+static int nilfs_unfreeze(struct super_block *sb)
	460	+{
	461	+ struct nilfs_sb_info *sbi = NILFS_SB(sb);
	462	+ struct the_nilfs *nilfs = sbi->s_nilfs;
	463	+
	464	+ if (sb->s_flags & MS_RDONLY)
	465	+ return 0;
	466	+
	467	+ down_write(&nilfs->ns_sem);
	468	+ nilfs_setup_super(sbi, false);
	469	+ up_write(&nilfs->ns_sem);
	470	+ return 0;
	471	+}
	472	+
442	473	static int nilfs_statfs(struct dentry dentry, struct kstatfs buf)
443	474	{
444	475	struct super_block *sb = dentry->d_sb;
...	...	@@ -523,6 +554,8 @@
523	554	.put_super = nilfs_put_super,
524	555	/* .write_super = nilfs_write_super, */
525	556	.sync_fs = nilfs_sync_fs,
	557	+ .freeze_fs = nilfs_freeze,
	558	+ .unfreeze_fs = nilfs_unfreeze,
526	559	/* .write_super_lockfs */
527	560	/* .unlockfs */
528	561	.statfs = nilfs_statfs,
...	...	@@ -626,7 +659,7 @@
626	659	NILFS_MOUNT_ERRORS_RO \| NILFS_MOUNT_BARRIER;
627	660	}
628	661
629		-static int nilfs_setup_super(struct nilfs_sb_info *sbi)
	662	+static int nilfs_setup_super(struct nilfs_sb_info *sbi, int is_mount)
630	663	{
631	664	struct the_nilfs *nilfs = sbi->s_nilfs;
632	665	struct nilfs_super_block **sbp;
...	...	@@ -638,6 +671,9 @@
638	671	if (!sbp)
639	672	return -EIO;
640	673
	674	+ if (!is_mount)
	675	+ goto skip_mount_setup;
	676	+
641	677	max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
642	678	mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
643	679
644	680
...	...	@@ -654,9 +690,11 @@
654	690	sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
655	691
656	692	sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
	693	+ sbp[0]->s_mtime = cpu_to_le64(get_seconds());
	694	+
	695	+skip_mount_setup:
657	696	sbp[0]->s_state =
658	697	cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
659		- sbp[0]->s_mtime = cpu_to_le64(get_seconds());
660	698	/* synchronize sbp[1] with sbp[0] */
661	699	memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
662	700	return nilfs_commit_super(sbi, NILFS_SB_COMMIT_ALL);
...	...	@@ -938,7 +976,7 @@
938	976
939	977	if (!(sb->s_flags & MS_RDONLY)) {
940	978	down_write(&nilfs->ns_sem);
941		- nilfs_setup_super(sbi);
	979	+ nilfs_setup_super(sbi, true);
942	980	up_write(&nilfs->ns_sem);
943	981	}
944	982
...	...	@@ -1034,7 +1072,7 @@
1034	1072	goto restore_opts;
1035	1073
1036	1074	down_write(&nilfs->ns_sem);
1037		- nilfs_setup_super(sbi);
	1075	+ nilfs_setup_super(sbi, true);
1038	1076	up_write(&nilfs->ns_sem);
1039	1077	}
1040	1078	out:
1041	1079
...	...	@@ -1132,7 +1170,19 @@
1132	1170	goto failed;
1133	1171	}
1134	1172
	1173	+ /*
	1174	+ * once the super is inserted into the list by sget, s_umount
	1175	+ * will protect the lockfs code from trying to start a snapshot
	1176	+ * while we are mounting
	1177	+ */
	1178	+ mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
	1179	+ if (sd.bdev->bd_fsfreeze_count > 0) {
	1180	+ mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
	1181	+ err = -EBUSY;
	1182	+ goto failed;
	1183	+ }
1135	1184	s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, sd.bdev);
	1185	+ mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1136	1186	if (IS_ERR(s)) {
1137	1187	err = PTR_ERR(s);
1138	1188	goto failed;