[RFC ONLY 3/8] btrfs: read raid-stripe-tree from disk

Johannes Thumshirn
2022-05-16T14:31:59Z

If we're discovering a raid-stripe-tree on mount, read it from disk.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
fs/btrfs/ctree.h | 1 +
fs/btrfs/disk-io.c | 12 ++++++++++++
include/uapi/linux/btrfs.h | 1 +
3 files changed, 14 insertions(+)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 20aa2ebac7cd..1db669662f61 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -667,6 +667,7 @@ struct btrfs_fs_info {
struct btrfs_root *uuid_root;
struct btrfs_root *data_reloc_root;
struct btrfs_root *block_group_root;
+ struct btrfs_root *stripe_root;

/* the log root tree is a directory of all the other log roots */
struct btrfs_root *log_root_tree;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index d456f426924c..c0f08917465a 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1706,6 +1706,9 @@ static struct btrfs_root *btrfs_get_global_root(struct btrfs_fs_info *fs_info,

return btrfs_grab_root(root) ? root : ERR_PTR(-ENOENT);
}
+ if (objectid == BTRFS_RAID_STRIPE_TREE_OBJECTID)
+ return btrfs_grab_root(fs_info->stripe_root) ?
+ fs_info->stripe_root : ERR_PTR(-ENOENT);
return NULL;
}

@@ -1784,6 +1787,7 @@ void btrfs_free_fs_info(struct btrfs_fs_info *fs_info)
btrfs_put_root(fs_info->fs_root);
btrfs_put_root(fs_info->data_reloc_root);
btrfs_put_root(fs_info->block_group_root);
+ btrfs_put_root(fs_info->stripe_root);
btrfs_check_leaked_roots(fs_info);
btrfs_extent_buffer_leak_debug_check(fs_info);
kfree(fs_info->super_copy);
@@ -2337,6 +2341,7 @@ static void free_root_pointers(struct btrfs_fs_info *info, bool free_chunk_root)
free_root_extent_buffers(info->fs_root);
free_root_extent_buffers(info->data_reloc_root);
free_root_extent_buffers(info->block_group_root);
+ free_root_extent_buffers(info->stripe_root);
if (free_chunk_root)
free_root_extent_buffers(info->chunk_root);
}
@@ -2773,6 +2778,13 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info)
fs_info->uuid_root = root;
}

+ location.objectid = BTRFS_RAID_STRIPE_TREE_OBJECTID;
+ root = btrfs_read_tree_root(tree_root, &location);
+ if (!IS_ERR(root)) {
+ set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
+ fs_info->stripe_root = root;
+ }
+
return 0;
out:
btrfs_warn(fs_info, "failed to read root (objectid=%llu): %d",
diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index d956b2993970..4e0429fc4e87 100644
--- a/include/uapi/linux/btrfs.h
+++ b/include/uapi/linux/btrfs.h
@@ -310,6 +310,7 @@ struct btrfs_ioctl_fs_info_args {
#define BTRFS_FEATURE_INCOMPAT_RAID1C34 (1ULL << 11)
#define BTRFS_FEATURE_INCOMPAT_ZONED (1ULL << 12)
#define BTRFS_FEATURE_INCOMPAT_EXTENT_TREE_V2 (1ULL << 13)
+#define BTRFS_FEATURE_INCOMPAT_STRIPE_TREE (1ULL << 14)

struct btrfs_ioctl_feature_flags {
__u64 compat_flags;
--
2.35.1