btrfs: add ref-verify mount option

This adds the infrastructure for turning ref verify on and off for a
mount, to be used by a later patch.

Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ enhnance btrfs_print_mod_info to print if ref-verify is compiled in ]
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ctree.h

@@ -1335,6 +1335,7 @@ static inline u32 BTRFS_MAX_XATTR_SIZE(const struct btrfs_fs_info *info)
 #define BTRFS_MOUNT_FRAGMENT_METADATA	(1 << 25)
 #define BTRFS_MOUNT_FREE_SPACE_TREE	(1 << 26)
 #define BTRFS_MOUNT_NOLOGREPLAY		(1 << 27)
+#define BTRFS_MOUNT_REF_VERIFY		(1 << 28)
 
 #define BTRFS_DEFAULT_COMMIT_INTERVAL	(30)
 #define BTRFS_DEFAULT_MAX_INLINE	(2048)

fs/btrfs/super.c

@@ -325,6 +325,9 @@ enum {
 	Opt_nologreplay, Opt_norecovery,
 #ifdef CONFIG_BTRFS_DEBUG
 	Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
+#endif
+#ifdef CONFIG_BTRFS_FS_REF_VERIFY
+	Opt_ref_verify,
 #endif
 	Opt_err,
 };
@@ -386,6 +389,9 @@ static const match_table_t tokens = {
 	{Opt_fragment_data, "fragment=data"},
 	{Opt_fragment_metadata, "fragment=metadata"},
 	{Opt_fragment_all, "fragment=all"},
+#endif
+#ifdef CONFIG_BTRFS_FS_REF_VERIFY
+	{Opt_ref_verify, "ref_verify"},
 #endif
 	{Opt_err, NULL},
 };
@@ -824,6 +830,12 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
 			btrfs_info(info, "fragmenting data");
 			btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 			break;
+#endif
+#ifdef CONFIG_BTRFS_FS_REF_VERIFY
+		case Opt_ref_verify:
+			btrfs_info(info, "doing ref verification");
+			btrfs_set_opt(info->mount_opt, REF_VERIFY);
+			break;
 #endif
 		case Opt_err:
 			btrfs_info(info, "unrecognized mount option '%s'", p);
@@ -1305,6 +1317,8 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
 	if (btrfs_test_opt(info, FRAGMENT_METADATA))
 		seq_puts(seq, ",fragment=metadata");
 #endif
+	if (btrfs_test_opt(info, REF_VERIFY))
+		seq_puts(seq, ",ref_verify");
 	seq_printf(seq, ",subvolid=%llu",
 		  BTRFS_I(d_inode(dentry))->root->root_key.objectid);
 	seq_puts(seq, ",subvol=");
@@ -2318,6 +2332,9 @@ static void btrfs_print_mod_info(void)
 #endif
 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 			", integrity-checker=on"
+#endif
+#ifdef CONFIG_BTRFS_FS_REF_VERIFY
+			", ref-verify=on"
 #endif
 			"\n",
 			btrfs_crc32c_impl());