btrfs-progs: add quota group verify code

This patch adds functionality (in qgroup-verify.c) to compute bytecounts in
subvolume quota groups. The original groups are read in and stored in memory
so that after we compute our own bytecounts, we can compare them with those
on disk. A print function is provided to do this comparison and show the
results on the console.

A 'qgroup check' pass is added to btrfsck. If any subvolume quota groups
differ from what we compute, the differences for them are printed.  We also
provide an option '--qgroup-report' which will run only the quota check code
and print a report on all quota groups.  Other than making it possible to
verify that our qgroup changes work correctly, this mode can also be used in
xfstests for automated checking after qgroup tests.

This patch does not address the following:
- compressed counts are identical to non compressed, because kernel doesn't
  make the distinction yet.  Adding the code to verify compressed counts
  shouldn't be hard at all though once kernel can do this.
- It is only concerned with subvolume quota groups (like most of
  btrfs-progs).

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

1 files changed, 14 insertions, 2 deletions

diff --git a/disk-io.c b/disk-io.c
index 8db0335b..58f3f07c 100644
--- a/disk-io.c
+++ b/disk-io.c
@@ -569,7 +569,6 @@ static int find_and_setup_log_root(struct btrfs_root *tree_root,
 	return 0;
 }
 
-
 int btrfs_free_fs_root(struct btrfs_root *root)
 {
 	if (root->node)
@@ -695,6 +694,8 @@ struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
 		return fs_info->dev_root;
 	if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
 		return fs_info->csum_root;
+	if (location->objectid == BTRFS_QUOTA_TREE_OBJECTID)
+		return fs_info->csum_root;
 
 	BUG_ON(location->objectid == BTRFS_TREE_RELOC_OBJECTID ||
 	       location->offset != (u64)-1);
@@ -721,6 +722,7 @@ void btrfs_free_fs_info(struct btrfs_fs_info *fs_info)
 	free(fs_info->chunk_root);
 	free(fs_info->dev_root);
 	free(fs_info->csum_root);
+	free(fs_info->quota_root);
 	free(fs_info->super_copy);
 	free(fs_info->log_root_tree);
 	free(fs_info);
@@ -741,11 +743,13 @@ struct btrfs_fs_info *btrfs_new_fs_info(int writable, u64 sb_bytenr)
 	fs_info->chunk_root = malloc(sizeof(struct btrfs_root));
 	fs_info->dev_root = malloc(sizeof(struct btrfs_root));
 	fs_info->csum_root = malloc(sizeof(struct btrfs_root));
+	fs_info->quota_root = malloc(sizeof(struct btrfs_root));
 	fs_info->super_copy = malloc(BTRFS_SUPER_INFO_SIZE);
 
 	if (!fs_info->tree_root || !fs_info->extent_root ||
 	    !fs_info->chunk_root || !fs_info->dev_root ||
-	    !fs_info->csum_root || !fs_info->super_copy)
+	    !fs_info->csum_root || !fs_info->quota_root ||
+	    !fs_info->super_copy)
 		goto free_all;
 
 	memset(fs_info->super_copy, 0, BTRFS_SUPER_INFO_SIZE);
@@ -754,6 +758,7 @@ struct btrfs_fs_info *btrfs_new_fs_info(int writable, u64 sb_bytenr)
 	memset(fs_info->chunk_root, 0, sizeof(struct btrfs_root));
 	memset(fs_info->dev_root, 0, sizeof(struct btrfs_root));
 	memset(fs_info->csum_root, 0, sizeof(struct btrfs_root));
+	memset(fs_info->quota_root, 0, sizeof(struct btrfs_root));
 
 	extent_io_tree_init(&fs_info->extent_cache);
 	extent_io_tree_init(&fs_info->free_space_cache);
@@ -912,6 +917,11 @@ int btrfs_setup_all_roots(struct btrfs_fs_info *fs_info, u64 root_tree_bytenr,
 	}
 	fs_info->csum_root->track_dirty = 1;
 
+	ret = find_and_setup_root(root, fs_info, BTRFS_QUOTA_TREE_OBJECTID,
+				  fs_info->quota_root);
+	if (ret == 0)
+		fs_info->quota_enabled = 1;
+
 	ret = find_and_setup_log_root(root, fs_info, sb);
 	if (ret) {
 		printk("Couldn't setup log root tree\n");
@@ -936,6 +946,8 @@ int btrfs_setup_all_roots(struct btrfs_fs_info *fs_info, u64 root_tree_bytenr,
 
 void btrfs_release_all_roots(struct btrfs_fs_info *fs_info)
 {
+	if (fs_info->quota_root)
+		free_extent_buffer(fs_info->quota_root->node);
 	if (fs_info->csum_root)
 		free_extent_buffer(fs_info->csum_root->node);
 	if (fs_info->dev_root)