btrfs-progs: check: write corrected qgroup info to disk

Now that we can verify all qgroups, we can write the corrected qgroups out
to disk when '--repair' is specified. The qgroup status item is also updated
to clear any out-of-date state. The repair_ functions were modeled after the
inode repair code in cmds-check.c.

I also renamed the 'scan' member of qgroup_status_item to 'rescan' in order
to keep consistency with the kernel.

Testing this was easy, I just reproduced qgroup inconsistencies via the
usual routes and had btrfsck fix them.

Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>

cmds-check.c

@@ -9655,6 +9655,7 @@ int cmd_check(int argc, char **argv)
 	int init_csum_tree = 0;
 	int readonly = 0;
 	int qgroup_report = 0;
+	int qgroups_repaired = 0;
 	enum btrfs_open_ctree_flags ctree_flags = OPEN_CTREE_EXCLUSIVE;
 
 	while(1) {
@@ -9810,7 +9811,7 @@ int cmd_check(int argc, char **argv)
 		       uuidbuf);
 		ret = qgroup_verify_all(info);
 		if (ret == 0)
-			ret = report_qgroups(1);
+			report_qgroups(1);
 		goto close_out;
 	}
 	if (subvolid) {
@@ -9964,6 +9965,10 @@ int cmd_check(int argc, char **argv)
 		err = qgroup_verify_all(info);
 		if (err)
 			goto out;
+		report_qgroups(0);
+		err = repair_qgroups(info, &qgroups_repaired);
+		if (err)
+			goto out;
 	}
 
 	if (!list_empty(&root->fs_info->recow_ebs)) {
@@ -9972,10 +9977,9 @@ int cmd_check(int argc, char **argv)
 	}
 out:
 	/* Don't override original ret */
-	if (ret)
-		report_qgroups(0);
-	else
-		ret = report_qgroups(0);
+	if (!ret && qgroups_repaired)
+		ret = qgroups_repaired;
+
 	if (found_old_backref) { /*
 		 * there was a disk format change when mixed
 		 * backref was in testing tree. The old format

ctree.h

@@ -898,7 +898,7 @@ struct btrfs_qgroup_status_item {
 	__le64 version;
 	__le64 generation;
 	__le64 flags;
-	__le64 scan;		/* progress during scanning */
+	__le64 rescan;		/* progress during scanning */
 } __attribute__ ((__packed__));
 
 struct btrfs_block_group_item {
@@ -2125,8 +2125,8 @@ BTRFS_SETGET_FUNCS(qgroup_status_generation, struct btrfs_qgroup_status_item,
 		   generation, 64);
 BTRFS_SETGET_FUNCS(qgroup_status_flags, struct btrfs_qgroup_status_item,
 		   flags, 64);
-BTRFS_SETGET_FUNCS(qgroup_status_scan, struct btrfs_qgroup_status_item,
-		   scan, 64);
+BTRFS_SETGET_FUNCS(qgroup_status_rescan, struct btrfs_qgroup_status_item,
+		   rescan, 64);
 
 BTRFS_SETGET_STACK_FUNCS(stack_qgroup_status_version,
 			 struct btrfs_qgroup_status_item, version, 64);
@@ -2134,8 +2134,8 @@ BTRFS_SETGET_STACK_FUNCS(stack_qgroup_status_generation,
 			 struct btrfs_qgroup_status_item, generation, 64);
 BTRFS_SETGET_STACK_FUNCS(stack_qgroup_status_flags,
 			 struct btrfs_qgroup_status_item, flags, 64);
-BTRFS_SETGET_STACK_FUNCS(stack_qgroup_status_scan,
-			 struct btrfs_qgroup_status_item, scan, 64);
+BTRFS_SETGET_STACK_FUNCS(stack_qgroup_status_rescan,
+			 struct btrfs_qgroup_status_item, rescan, 64);
 
 /* btrfs_qgroup_info_item */
 BTRFS_SETGET_FUNCS(qgroup_info_generation, struct btrfs_qgroup_info_item,

print-tree.c

@@ -1037,7 +1037,7 @@ void btrfs_print_leaf(struct btrfs_root *root, struct extent_buffer *l)
 				btrfs_qgroup_status_generation(l, qg_status),
 				flags_str,
 				(unsigned long long)
-				btrfs_qgroup_status_scan(l, qg_status));
+				btrfs_qgroup_status_rescan(l, qg_status));
 			break;
 		case BTRFS_QGROUP_RELATION_KEY:
 			break;

qgroup-verify.c

@@ -29,6 +29,8 @@
 #include "utils.h"
 #include "ulist.h"
 #include "rbtree-utils.h"
+#include "transaction.h"
+#include "repair.h"
 
 #include "qgroup-verify.h"
 
@@ -66,6 +68,8 @@ struct qgroup_count {
 	struct list_head members;
 
 	u64 cur_refcnt;
+
+	struct list_head bad_list;
 };
 
 static struct counts_tree {
@@ -75,6 +79,8 @@ static struct counts_tree {
 	unsigned int		qgroup_inconsist:1;
 } counts = { .root = RB_ROOT };
 
+static LIST_HEAD(bad_qgroups);
+
 static struct rb_root by_bytenr = RB_ROOT;
 
 /*
@@ -819,6 +825,7 @@ static struct qgroup_count *alloc_count(struct btrfs_disk_key *key,
 			btrfs_qgroup_info_exclusive_compressed(leaf, disk);
 		INIT_LIST_HEAD(&c->groups);
 		INIT_LIST_HEAD(&c->members);
+		INIT_LIST_HEAD(&c->bad_list);
 
 		if (insert_count(c)) {
 			free(c);
@@ -1250,34 +1257,36 @@ static int report_qgroup_difference(struct qgroup_count *count, int verbose)
 			print_fields_signed(excl_diff, excl_diff,
 					    "diff:", "exclusive");
 	}
-	return (is_different && count->subvol_exists);
+
+	return is_different;
 }
 
-int report_qgroups(int all)
+void report_qgroups(int all)
 {
 	struct rb_node *node;
 	struct qgroup_count *c;
-	int ret = 0;
 
-	if (counts.rescan_running) {
+	if (!repair && counts.rescan_running) {
 		if (all) {
 			printf(
-	"Qgroup rescan is running, qgroup counts difference is expected\n");
+	"Qgroup rescan is running, a difference in qgroup counts is expected\n");
 		} else {
 			printf(
-	"Qgroup rescan is running, ignore qgroup check\n");
-			return ret;
+	"Qgroup rescan is running, qgroups will not be printed.\n");
+			return;
 		}
 	}
 	if (counts.qgroup_inconsist && !counts.rescan_running)
-		fprintf(stderr, "Qgroup is already inconsistent before checking\n");
+		fprintf(stderr, "Qgroup are marked as inconsistent.\n");
 	node = rb_first(&counts.root);
 	while (node) {
 		c = rb_entry(node, struct qgroup_count, rb_node);
-		ret |= report_qgroup_difference(c, all);
+
+		if (report_qgroup_difference(c, all))
+			list_add_tail(&c->bad_list, &bad_qgroups);
+
 		node = rb_next(node);
 	}
-	return ret;
 }
 
 void free_qgroup_counts(void)
@@ -1290,6 +1299,8 @@ void free_qgroup_counts(void)
 	while (node) {
 		c = rb_entry(node, struct qgroup_count, rb_node);
 
+		list_del(&c->bad_list);
+
 		list_for_each_entry_safe(glist, tmpglist, &c->groups,
 					 next_group) {
 			list_del(&glist->next_group);
@@ -1425,3 +1436,150 @@ out:
 	return ret;
 }
 
+static int repair_qgroup_info(struct btrfs_fs_info *info,
+			      struct qgroup_count *count)
+{
+	int ret;
+	struct btrfs_root *root = info->quota_root;
+	struct btrfs_trans_handle *trans;
+	struct btrfs_path *path;
+	struct btrfs_qgroup_info_item *info_item;
+	struct btrfs_key key;
+
+	printf("Repair qgroup %llu/%llu\n", btrfs_qgroup_level(count->qgroupid),
+	       btrfs_qgroup_subvid(count->qgroupid));
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	trans = btrfs_start_transaction(root, 1);
+	if (IS_ERR(trans)) {
+		btrfs_free_path(path);
+		return PTR_ERR(trans);
+	}
+
+	key.objectid = 0;
+	key.type = BTRFS_QGROUP_INFO_KEY;
+	key.offset = count->qgroupid;
+	ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
+	if (ret) {
+		error("Could not find disk item for qgroup %llu/%llu.\n",
+		      btrfs_qgroup_level(count->qgroupid),
+		      btrfs_qgroup_subvid(count->qgroupid));
+		if (ret > 0)
+			ret = -ENOENT;
+		goto out;
+	}
+
+	info_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
+				   struct btrfs_qgroup_info_item);
+
+	btrfs_set_qgroup_info_generation(path->nodes[0], info_item,
+					 trans->transid);
+
+	btrfs_set_qgroup_info_referenced(path->nodes[0], info_item,
+					 count->info.referenced);
+	btrfs_set_qgroup_info_referenced_compressed(path->nodes[0], info_item,
+					    count->info.referenced_compressed);
+
+	btrfs_set_qgroup_info_exclusive(path->nodes[0], info_item,
+					count->info.exclusive);
+	btrfs_set_qgroup_info_exclusive_compressed(path->nodes[0], info_item,
+					   count->info.exclusive_compressed);
+
+	btrfs_mark_buffer_dirty(path->nodes[0]);
+
+out:
+	btrfs_commit_transaction(trans, root);
+	btrfs_free_path(path);
+
+	return ret;
+}
+
+static int repair_qgroup_status(struct btrfs_fs_info *info)
+{
+	int ret;
+	struct btrfs_root *root = info->quota_root;
+	struct btrfs_trans_handle *trans;
+	struct btrfs_path *path;
+	struct btrfs_key key;
+	struct btrfs_qgroup_status_item *status_item;
+
+	printf("Repair qgroup status item\n");
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	trans = btrfs_start_transaction(root, 1);
+	if (IS_ERR(trans)) {
+		btrfs_free_path(path);
+		return PTR_ERR(trans);
+	}
+
+	key.objectid = 0;
+	key.type = BTRFS_QGROUP_STATUS_KEY;
+	key.offset = 0;
+	ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
+	if (ret) {
+		error("Could not find qgroup status item\n");
+		if (ret > 0)
+			ret = -ENOENT;
+		goto out;
+	}
+
+	status_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
+				     struct btrfs_qgroup_status_item);
+	btrfs_set_qgroup_status_flags(path->nodes[0], status_item,
+				      BTRFS_QGROUP_STATUS_FLAG_ON);
+	btrfs_set_qgroup_status_rescan(path->nodes[0], status_item, 0);
+	btrfs_set_qgroup_status_generation(path->nodes[0], status_item,
+					   trans->transid);
+
+	btrfs_mark_buffer_dirty(path->nodes[0]);
+
+out:
+	btrfs_commit_transaction(trans, root);
+	btrfs_free_path(path);
+
+	return ret;
+}
+
+int repair_qgroups(struct btrfs_fs_info *info, int *repaired)
+{
+	int ret;
+	struct qgroup_count *count, *tmpcount;
+
+	*repaired = 0;
+
+	if (!repair)
+		return 0;
+
+	list_for_each_entry_safe(count, tmpcount, &bad_qgroups, bad_list) {
+		ret = repair_qgroup_info(info, count);
+		if (ret) {
+			goto out;
+		}
+
+		(*repaired)++;
+
+		list_del_init(&count->bad_list);
+	}
+
+	/*
+	 * Do this step last as we want the latest transaction id on
+	 * our qgroup status to avoid a (useless) warning after
+	 * mount.
+	 */
+	if (*repaired || counts.qgroup_inconsist || counts.rescan_running) {
+		ret = repair_qgroup_status(info);
+		if (ret)
+			goto out;
+
+		(*repaired)++;
+	}
+
+out:
+	return ret;
+}

qgroup-verify.h

@@ -23,7 +23,8 @@
 #include "ctree.h"
 
 int qgroup_verify_all(struct btrfs_fs_info *info);
-int report_qgroups(int all);
+void report_qgroups(int all);
+int repair_qgroups(struct btrfs_fs_info *info, int *repaired);
 
 int print_extent_state(struct btrfs_fs_info *info, u64 subvol);