Btrfs: start of support for many FS volumes

Signed-off-by: Chris Mason <chris.mason@oracle.com>

fs/btrfs/TODO

@@ -19,3 +19,10 @@
 * fsck
 * Scrub & defrag
 
+---
+metata FS ideas:
+mount metadata FS on /sys/fs/btrfs/dev/
+subvolumes in /sys/fs/btrfs/dev/fs/
+snapshots in /sys/fs/btrfs/dev/fs/snapshots
+mount -o bind
+ioctl to create a snapshot

fs/btrfs/btrfs_inode.h

@@ -3,6 +3,8 @@
 
 struct btrfs_inode {
 	u32 magic;
+	struct btrfs_root *root;
+	struct btrfs_key location;
 	struct inode vfs_inode;
 	u32 magic2;
 };

fs/btrfs/ctree.h

@@ -3,6 +3,7 @@
 
 #include <linux/fs.h>
 #include <linux/buffer_head.h>
+#include <linux/kobject.h>
 #include "bit-radix.h"
 
 struct btrfs_trans_handle;
@@ -183,13 +184,15 @@ struct btrfs_inline_data_item {
 } __attribute__ ((__packed__));
 
 struct btrfs_dir_item {
-	__le64 objectid;
+	struct btrfs_disk_key location;
 	__le16 flags;
 	__le16 name_len;
 	u8 type;
 } __attribute__ ((__packed__));
 
 struct btrfs_root_item {
+	struct btrfs_inode_item inode;
+	__le64 root_dirid;
 	__le64 blocknr;
 	__le32 flags;
 	__le64 block_limit;
@@ -249,6 +252,7 @@ struct btrfs_fs_info {
 	struct mutex fs_mutex;
 	struct crypto_hash *hash_tfm;
 	spinlock_t hash_lock;
+	struct kobject kobj;
 };
 
 /*
@@ -504,16 +508,6 @@ static inline void btrfs_set_item_size(struct btrfs_item *item, u16 val)
 	item->size = cpu_to_le16(val);
 }
 
-static inline u64 btrfs_dir_objectid(struct btrfs_dir_item *d)
-{
-	return le64_to_cpu(d->objectid);
-}
-
-static inline void btrfs_set_dir_objectid(struct btrfs_dir_item *d, u64 val)
-{
-	d->objectid = cpu_to_le64(val);
-}
-
 static inline u16 btrfs_dir_flags(struct btrfs_dir_item *d)
 {
 	return le16_to_cpu(d->flags);
@@ -724,6 +718,16 @@ static inline void btrfs_set_root_blocknr(struct btrfs_root_item *item, u64 val)
 	item->blocknr = cpu_to_le64(val);
 }
 
+static inline u64 btrfs_root_dirid(struct btrfs_root_item *item)
+{
+	return le64_to_cpu(item->root_dirid);
+}
+
+static inline void btrfs_set_root_dirid(struct btrfs_root_item *item, u64 val)
+{
+	item->root_dirid = cpu_to_le64(val);
+}
+
 static inline u32 btrfs_root_refs(struct btrfs_root_item *item)
 {
 	return le32_to_cpu(item->refs);
@@ -950,8 +954,8 @@ int btrfs_find_last_root(struct btrfs_root *root, u64 objectid, struct
 			 btrfs_root_item *item, struct btrfs_key *key);
 /* dir-item.c */
 int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
-			  *root, const char *name, int name_len, u64 dir, u64
-			  objectid, u8 type);
+			  *root, const char *name, int name_len, u64 dir,
+			  struct btrfs_key *location, u8 type);
 int btrfs_lookup_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
 			  *root, struct btrfs_path *path, u64 dir,
 			  const char *name, int name_len, int mod);
@@ -978,7 +982,8 @@ int btrfs_insert_inode(struct btrfs_trans_handle *trans, struct btrfs_root
 		       *root, u64 objectid, struct btrfs_inode_item
 		       *inode_item);
 int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
-		       *root, struct btrfs_path *path, u64 objectid, int mod);
+		       *root, struct btrfs_path *path,
+		       struct btrfs_key *location, int mod);
 
 /* file-item.c */
 int btrfs_alloc_file_extent(struct btrfs_trans_handle *trans,
@@ -997,4 +1002,7 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
 int btrfs_csum_verify_file_block(struct btrfs_root *root,
 				 u64 objectid, u64 offset,
 				 char *data, size_t len);
+/* super.c */
+extern struct subsystem btrfs_subsys;
+
 #endif

fs/btrfs/dir-item.c

@@ -25,8 +25,8 @@ int insert_with_overflow(struct btrfs_trans_handle *trans, struct btrfs_root
 }
 
 int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
-			  *root, const char *name, int name_len, u64 dir, u64
-			  objectid, u8 type)
+			  *root, const char *name, int name_len, u64 dir,
+			  struct btrfs_key *location, u8 type)
 {
 	int ret = 0;
 	struct btrfs_path *path;
@@ -50,17 +50,21 @@ int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
 	dir_item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
 				  path->slots[0],
 				  struct btrfs_dir_item);
-	btrfs_set_dir_objectid(dir_item, objectid);
+	btrfs_cpu_key_to_disk(&dir_item->location, location);
 	btrfs_set_dir_type(dir_item, type);
 	btrfs_set_dir_flags(dir_item, 0);
 	btrfs_set_dir_name_len(dir_item, name_len);
 	name_ptr = (char *)(dir_item + 1);
+	/* FIXME, use some real flag for selecting the extra index */
+	if (root == root->fs_info->tree_root)
+		goto out;
+
 	btrfs_memcpy(root, path->nodes[0]->b_data, name_ptr, name, name_len);
 	btrfs_mark_buffer_dirty(path->nodes[0]);
 	btrfs_release_path(root, path);
 
 	btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
-	key.offset = objectid;
+	key.offset = location->objectid;
 	ret = insert_with_overflow(trans, root, path, &key, data_size);
 	// FIXME clear the dirindex bit
 	if (ret)
@@ -69,7 +73,7 @@ int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
 	dir_item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
 				  path->slots[0],
 				  struct btrfs_dir_item);
-	btrfs_set_dir_objectid(dir_item, objectid);
+	btrfs_cpu_key_to_disk(&dir_item->location, location);
 	btrfs_set_dir_type(dir_item, type);
 	btrfs_set_dir_flags(dir_item, 0);
 	btrfs_set_dir_name_len(dir_item, name_len);

fs/btrfs/disk-io.c

@@ -338,7 +338,6 @@ struct btrfs_root *open_ctree(struct super_block *sb)
 					     sb->s_blocksize);
 
 	if (!fs_info->sb_buffer) {
-printk("failed2\n");
 		return NULL;
 	}
 	disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data;
@@ -369,6 +368,10 @@ printk("failed2\n");
 	ret = btrfs_find_highest_inode(root, &root->fs_info->last_inode_alloc);
 	if (ret == 0)
 		fs_info->highest_inode = fs_info->last_inode_alloc;
+	memset(&fs_info->kobj, 0, sizeof(fs_info->kobj));
+	kobj_set_kset_s(fs_info, btrfs_subsys);
+	kobject_set_name(&fs_info->kobj, "%s", sb->s_id);
+	kobject_register(&fs_info->kobj);
 	mutex_unlock(&fs_info->fs_mutex);
 	return root;
 }
@@ -430,7 +433,7 @@ int close_ctree(struct btrfs_root *root)
 	kfree(root->fs_info->extent_root);
 	kfree(root->fs_info->inode_root);
 	kfree(root->fs_info->tree_root);
-	kfree(root->fs_info);
+	kobject_unregister(&root->fs_info->kobj);
 	kfree(root);
 	return 0;
 }

fs/btrfs/inode-item.c

@@ -26,15 +26,27 @@ int btrfs_insert_inode(struct btrfs_trans_handle *trans, struct btrfs_root
 }
 
 int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
-		       *root, struct btrfs_path *path, u64 objectid, int mod)
+		       *root, struct btrfs_path *path,
+		       struct btrfs_key *location, int mod)
 {
-	struct btrfs_key key;
 	int ins_len = mod < 0 ? -1 : 0;
 	int cow = mod != 0;
+	int ret;
+	int slot;
+	struct btrfs_leaf *leaf;
+	struct btrfs_key found_key;
 
-	key.objectid = objectid;
-	key.flags = 0;
-	btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
-	key.offset = 0;
-	return btrfs_search_slot(trans, root, &key, path, ins_len, cow);
+	ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
+	if (ret > 0 && btrfs_key_type(location) == BTRFS_ROOT_ITEM_KEY &&
+	    location->offset == (u64)-1 && path->slots[0] != 0) {
+		slot = path->slots[0] - 1;
+		leaf = btrfs_buffer_leaf(path->nodes[0]);
+		btrfs_disk_key_to_cpu(&found_key, &leaf->items[slot].key);
+		if (found_key.objectid == location->objectid &&
+		    btrfs_key_type(&found_key) == btrfs_key_type(location)) {
+			path->slots[0]--;
+			return 0;
+		}
+	}
+	return ret;
 }

fs/btrfs/print-tree.c

@@ -38,7 +38,7 @@ void btrfs_print_leaf(struct btrfs_root *root, struct btrfs_leaf *l)
 		case BTRFS_DIR_ITEM_KEY:
 			di = btrfs_item_ptr(l, i, struct btrfs_dir_item);
 			printk("\t\tdir oid %Lu flags %u type %u\n",
-				btrfs_dir_objectid(di),
+				btrfs_disk_key_objectid(&di->location),
 				btrfs_dir_flags(di),
 				btrfs_dir_type(di));
 			printk("\t\tname %.*s\n",

fs/btrfs/transaction.c

@@ -52,6 +52,8 @@ struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
 		kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
 	int ret;
 
+	/* FIXME, use the right root */
+	root = root->fs_info->fs_root;
 	mutex_lock(&root->fs_info->trans_mutex);
 	ret = join_transaction(root);
 	BUG_ON(ret);
@@ -69,6 +71,10 @@ int btrfs_end_transaction(struct btrfs_trans_handle *trans,
 			  struct btrfs_root *root)
 {
 	struct btrfs_transaction *cur_trans;
+
+	/* FIXME, use the right root */
+	root = root->fs_info->fs_root;
+
 	WARN_ON(trans->magic != TRANS_MAGIC);
 	WARN_ON(trans->magic2 != TRANS_MAGIC);
 	mutex_lock(&root->fs_info->trans_mutex);
@@ -148,6 +154,9 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 	struct btrfs_transaction *cur_trans;
 	DEFINE_WAIT(wait);
 
+	/* FIXME, use the right root */
+	root = root->fs_info->fs_root;
+
 	mutex_lock(&root->fs_info->trans_mutex);
 	if (trans->transaction->in_commit) {
 printk("already in commit!, waiting\n");