Btrfs: start of support for many FS volumes

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

9 files changed, 242 insertions, 79 deletions

diff --git a/fs/btrfs/TODO b/fs/btrfs/TODO
index ea4c38c790b4..73d4b842a316 100644
--- a/fs/btrfs/TODO
+++ b/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
diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index e159841650a4..3439ffb467b5 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/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;
 };
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 6d40758b893f..1ff5b99af682 100644
--- a/fs/btrfs/ctree.h
+++ b/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
diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
index 0ee9945fb1b0..7aed9f015b55 100644
--- a/fs/btrfs/dir-item.c
+++ b/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);
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 5230554380d1..b9301a5e4608 100644
--- a/fs/btrfs/disk-io.c
+++ b/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;
 }
diff --git a/fs/btrfs/inode-item.c b/fs/btrfs/inode-item.c
index 6bfa980790c2..b276a3b40a66 100644
--- a/fs/btrfs/inode-item.c
+++ b/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;
 }
diff --git a/fs/btrfs/print-tree.c b/fs/btrfs/print-tree.c
index c8ee938c1251..f0da65c4f96b 100644
--- a/fs/btrfs/print-tree.c
+++ b/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",
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 32224ffdcecd..66d9fb2288c3 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -16,9 +16,23 @@
 #include "transaction.h"
 #include "btrfs_inode.h"
 
+void btrfs_fsinfo_release(struct kobject *obj)
+{
+        struct btrfs_fs_info *fsinfo = container_of(obj,
+                                            struct btrfs_fs_info, kobj);
+        kfree(fsinfo);
+}
+
+struct kobj_type btrfs_fsinfo_ktype = {
+        .release = btrfs_fsinfo_release,
+};
+
+decl_subsys(btrfs, &btrfs_fsinfo_ktype, NULL);
+
 #define BTRFS_SUPER_MAGIC 0x9123682E
 
 static struct inode_operations btrfs_dir_inode_operations;
+static struct inode_operations btrfs_dir_ro_inode_operations;
 static struct super_operations btrfs_super_ops;
 static struct file_operations btrfs_dir_file_operations;
 static struct inode_operations btrfs_file_inode_operations;
@@ -37,7 +51,8 @@ static void btrfs_read_locked_inode(struct inode *inode)
 {
         struct btrfs_path *path;
         struct btrfs_inode_item *inode_item;
-        struct btrfs_root *root = btrfs_sb(inode->i_sb);
+        struct btrfs_root *root = BTRFS_I(inode)->root;
+        struct btrfs_key location;
         int ret;
 
         path = btrfs_alloc_path();
@@ -46,13 +61,12 @@ static void btrfs_read_locked_inode(struct inode *inode)
         mutex_lock(&root->fs_info->fs_mutex);
 
         check_inode(inode);
-        ret = btrfs_lookup_inode(NULL, root, path, inode->i_ino, 0);
+
+        memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
+        ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
         if (ret) {
-                btrfs_release_path(root, path);
                 btrfs_free_path(path);
-                mutex_unlock(&root->fs_info->fs_mutex);
-                make_bad_inode(inode);
-                return;
+                goto make_bad;
         }
         check_inode(inode);
         inode_item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
@@ -73,7 +87,6 @@ static void btrfs_read_locked_inode(struct inode *inode)
         inode->i_blocks = btrfs_inode_nblocks(inode_item);
         inode->i_generation = btrfs_inode_generation(inode_item);
 
-        btrfs_release_path(root, path);
         btrfs_free_path(path);
         inode_item = NULL;
 
@@ -92,8 +105,11 @@ static void btrfs_read_locked_inode(struct inode *inode)
                 inode->i_op = &btrfs_file_inode_operations;
                 break;
         case S_IFDIR:
-                inode->i_op = &btrfs_dir_inode_operations;
                 inode->i_fop = &btrfs_dir_file_operations;
+                if (root == root->fs_info->tree_root)
+                        inode->i_op = &btrfs_dir_ro_inode_operations;
+                else
+                        inode->i_op = &btrfs_dir_inode_operations;
                 break;
         case S_IFLNK:
                 // inode->i_op = &page_symlink_inode_operations;
@@ -101,6 +117,12 @@ static void btrfs_read_locked_inode(struct inode *inode)
         }
         check_inode(inode);
         return;
+
+make_bad:
+        btrfs_release_path(root, path);
+        btrfs_free_path(path);
+        mutex_unlock(&root->fs_info->fs_mutex);
+        make_bad_inode(inode);
 }
 
 static int btrfs_unlink_trans(struct btrfs_trans_handle *trans,
@@ -128,7 +150,7 @@ static int btrfs_unlink_trans(struct btrfs_trans_handle *trans,
         }
         di = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
                             struct btrfs_dir_item);
-        objectid = btrfs_dir_objectid(di);
+        objectid = btrfs_disk_key_objectid(&di->location);
 
         ret = btrfs_del_item(trans, root, path);
         BUG_ON(ret);
@@ -157,7 +179,7 @@ static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
         struct btrfs_trans_handle *trans;
         int ret;
 
-        root = btrfs_sb(dir->i_sb);
+        root = BTRFS_I(dir)->root;
         mutex_lock(&root->fs_info->fs_mutex);
         trans = btrfs_start_transaction(root, 1);
         ret = btrfs_unlink_trans(trans, root, dir, dentry);
@@ -171,7 +193,7 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
         struct inode *inode = dentry->d_inode;
         int err;
         int ret;
-        struct btrfs_root *root = btrfs_sb(dir->i_sb);
+        struct btrfs_root *root = BTRFS_I(dir)->root;
         struct btrfs_path *path;
         struct btrfs_key key;
         struct btrfs_trans_handle *trans;
@@ -268,7 +290,8 @@ static int btrfs_free_inode(struct btrfs_trans_handle *trans,
         BUG_ON(ret);
         btrfs_release_path(root, path);
 
-        ret = btrfs_lookup_inode(trans, root, path, objectid, -1);
+        ret = btrfs_lookup_inode(trans, root, path,
+                                 &BTRFS_I(inode)->location, -1);
         BUG_ON(ret);
         ret = btrfs_del_item(trans, root, path);
         BUG_ON(ret);
@@ -355,7 +378,7 @@ error:
 static void btrfs_delete_inode(struct inode *inode)
 {
         struct btrfs_trans_handle *trans;
-        struct btrfs_root *root = btrfs_sb(inode->i_sb);
+        struct btrfs_root *root = BTRFS_I(inode)->root;
         int ret;
 
         truncate_inode_pages(&inode->i_data, 0);
@@ -378,13 +401,13 @@ no_delete:
 }
 
 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
-                              ino_t *ino)
+                               struct btrfs_key *location)
 {
         const char *name = dentry->d_name.name;
         int namelen = dentry->d_name.len;
         struct btrfs_dir_item *di;
         struct btrfs_path *path;
-        struct btrfs_root *root = btrfs_sb(dir->i_sb);
+        struct btrfs_root *root = BTRFS_I(dir)->root;
         int ret;
 
         path = btrfs_alloc_path();
@@ -393,13 +416,13 @@ static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
         ret = btrfs_lookup_dir_item(NULL, root, path, dir->i_ino, name,
                                     namelen, 0);
         if (ret || !btrfs_match_dir_item_name(root, path, name, namelen)) {
-                *ino = 0;
+                location->objectid = 0;
                 ret = 0;
                 goto out;
         }
         di = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
                             struct btrfs_dir_item);
-        *ino = btrfs_dir_objectid(di);
+        btrfs_disk_key_to_cpu(location, &di->location);
 out:
         btrfs_release_path(root, path);
         btrfs_free_path(path);
@@ -407,26 +430,76 @@ out:
         return ret;
 }
 
+int fixup_tree_root_location(struct btrfs_root *root,
+                             struct btrfs_key *location,
+                             struct btrfs_root **sub_root)
+{
+        struct btrfs_path *path;
+        struct btrfs_root_item *ri;
+        int ret;
+
+        if (btrfs_key_type(location) != BTRFS_ROOT_ITEM_KEY)
+                return 0;
+        if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
+                return 0;
+
+        path = btrfs_alloc_path();
+        BUG_ON(!path);
+        mutex_lock(&root->fs_info->fs_mutex);
+
+        ret = btrfs_lookup_inode(NULL, root, path, location, 0);
+        if (ret)
+                goto out;
+        ri = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
+                          path->slots[0],
+                          struct btrfs_root_item);
+        location->objectid = btrfs_root_dirid(ri);
+        location->flags = 0;
+        btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
+        location->offset = 0;
+        /* FIXME properly select the root */
+        *sub_root = root->fs_info->fs_root;
+out:
+        btrfs_free_path(path);
+        mutex_unlock(&root->fs_info->fs_mutex);
+        return ret;
+}
+
+
 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
                                    struct nameidata *nd)
 {
         struct inode * inode;
-        struct btrfs_root *root = btrfs_sb(dir->i_sb);
-        ino_t ino;
+        struct btrfs_inode *bi = BTRFS_I(dir);
+        struct btrfs_root *root = bi->root;
+        struct btrfs_root *sub_root = root;
+        struct btrfs_key location;
         int ret;
 
         if (dentry->d_name.len > BTRFS_NAME_LEN)
                 return ERR_PTR(-ENAMETOOLONG);
         mutex_lock(&root->fs_info->fs_mutex);
-        ret = btrfs_inode_by_name(dir, dentry, &ino);
+        ret = btrfs_inode_by_name(dir, dentry, &location);
         mutex_unlock(&root->fs_info->fs_mutex);
         if (ret < 0)
                 return ERR_PTR(ret);
         inode = NULL;
-        if (ino) {
-                inode = iget(dir->i_sb, ino);
+        if (location.objectid) {
+                ret = fixup_tree_root_location(root, &location, &sub_root);
+                if (ret < 0)
+                        return ERR_PTR(ret);
+                if (ret > 0)
+                        return ERR_PTR(-ENOENT);
+                inode = iget_locked(dir->i_sb, location.objectid);
                 if (!inode)
                         return ERR_PTR(-EACCES);
+                if (inode->i_state & I_NEW) {
+                        BTRFS_I(inode)->root = sub_root;
+                        memcpy(&BTRFS_I(inode)->location, &location,
+                               sizeof(location));
+                        btrfs_read_locked_inode(inode);
+                        unlock_new_inode(inode);
+                }
                 check_inode(inode);
         }
         check_inode(dir);
@@ -436,7 +509,7 @@ static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
 static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
 {
         struct inode *inode = filp->f_path.dentry->d_inode;
-        struct btrfs_root *root = btrfs_sb(inode->i_sb);
+        struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_item *item;
         struct btrfs_dir_item *di;
         struct btrfs_key key;
@@ -448,11 +521,16 @@ static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
         int advance;
         unsigned char d_type = DT_UNKNOWN;
         int over = 0;
+        int key_type = BTRFS_DIR_INDEX_KEY;
+
+        /* FIXME, use a real flag for deciding about the key type */
+        if (root->fs_info->tree_root == root)
+                key_type = BTRFS_DIR_ITEM_KEY;
 
         mutex_lock(&root->fs_info->fs_mutex);
         key.objectid = inode->i_ino;
         key.flags = 0;
-        btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
+        btrfs_set_key_type(&key, key_type);
         key.offset = filp->f_pos;
         path = btrfs_alloc_path();
         btrfs_init_path(path);
@@ -482,10 +560,11 @@ static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
                 item = leaf->items + slot;
                 if (btrfs_disk_key_objectid(&item->key) != key.objectid)
                         break;
-                if (btrfs_disk_key_offset(&item->key) >
+                if (key_type == BTRFS_DIR_INDEX_KEY &&
+                    btrfs_disk_key_offset(&item->key) >
                     root->fs_info->highest_inode)
                         break;
-                if (btrfs_disk_key_type(&item->key) != BTRFS_DIR_INDEX_KEY)
+                if (btrfs_disk_key_type(&item->key) != key_type)
                         continue;
                 if (btrfs_disk_key_offset(&item->key) < filp->f_pos)
                         continue;
@@ -495,7 +574,7 @@ static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
                 over = filldir(dirent, (const char *)(di + 1),
                                btrfs_dir_name_len(di),
                                btrfs_disk_key_offset(&item->key),
-                               btrfs_dir_objectid(di), d_type);
+                               btrfs_disk_key_objectid(&di->location), d_type);
                 if (over)
                         goto nopos;
         }
@@ -527,6 +606,7 @@ static int btrfs_fill_super(struct super_block * sb, void * data, int silent)
         struct dentry * root_dentry;
         struct btrfs_super_block *disk_super;
         struct btrfs_root *root;
+        struct btrfs_inode *bi;
 
         sb->s_maxbytes = MAX_LFS_FILESIZE;
         sb->s_magic = BTRFS_SUPER_MAGIC;
@@ -546,6 +626,13 @@ static int btrfs_fill_super(struct super_block * sb, void * data, int silent)
                btrfs_super_root_dir(disk_super));
 
         inode = iget_locked(sb, btrfs_super_root_dir(disk_super));
+        bi = BTRFS_I(inode);
+        bi->location.objectid = inode->i_ino;
+        bi->location.offset = 0;
+        bi->location.flags = 0;
+        bi->root = root->fs_info->tree_root;
+        btrfs_set_key_type(&bi->location, BTRFS_INODE_ITEM_KEY);
+
         if (!inode)
                 return -ENOMEM;
         if (inode->i_state & I_NEW) {
@@ -594,7 +681,8 @@ static int btrfs_update_inode(struct btrfs_trans_handle *trans,
         BUG_ON(!path);
         btrfs_init_path(path);
 
-        ret = btrfs_lookup_inode(trans, root, path, inode->i_ino, 1);
+        ret = btrfs_lookup_inode(trans, root, path,
+                                 &BTRFS_I(inode)->location, 1);
         if (ret) {
                 if (ret > 0)
                         ret = -ENOENT;
@@ -616,7 +704,7 @@ failed:
 
 static int btrfs_write_inode(struct inode *inode, int wait)
 {
-        struct btrfs_root *root = btrfs_sb(inode->i_sb);
+        struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_trans_handle *trans;
         int ret;
 
@@ -637,8 +725,8 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
 {
         struct inode *inode;
         struct btrfs_inode_item inode_item;
-        struct btrfs_root *root = btrfs_sb(dir->i_sb);
-        struct btrfs_key key;
+        struct btrfs_root *root = BTRFS_I(dir)->root;
+        struct btrfs_key *key;
         int ret;
         u64 objectid;
 
@@ -646,6 +734,8 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
         if (!inode)
                 return ERR_PTR(-ENOMEM);
 
+        BTRFS_I(inode)->root = BTRFS_I(dir)->root;
+        key = &BTRFS_I(inode)->location;
         check_inode(inode);
         ret = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
         BUG_ON(ret);
@@ -658,11 +748,11 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
         fill_inode_item(&inode_item, inode);
 
-        key.objectid = objectid;
-        key.flags = 0;
-        key.offset = 0;
-        btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
-        ret = btrfs_insert_inode_map(trans, root, objectid, &key);
+        key->objectid = objectid;
+        key->flags = 0;
+        key->offset = 0;
+        btrfs_set_key_type(key, BTRFS_INODE_ITEM_KEY);
+        ret = btrfs_insert_inode_map(trans, root, objectid, key);
         BUG_ON(ret);
 
         ret = btrfs_insert_inode(trans, root, objectid, &inode_item);
@@ -678,13 +768,20 @@ static int btrfs_add_link(struct btrfs_trans_handle *trans,
                             struct dentry *dentry, struct inode *inode)
 {
         int ret;
-        ret = btrfs_insert_dir_item(trans, btrfs_sb(inode->i_sb),
+        struct btrfs_key key;
+        struct btrfs_root *root = BTRFS_I(dentry->d_parent->d_inode)->root;
+        key.objectid = inode->i_ino;
+        key.flags = 0;
+        btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
+        key.offset = 0;
+
+        ret = btrfs_insert_dir_item(trans, root,
                                     dentry->d_name.name, dentry->d_name.len,
                                     dentry->d_parent->d_inode->i_ino,
-                                    inode->i_ino, 0);
+                                    &key, 0);
         if (ret == 0) {
                 dentry->d_parent->d_inode->i_size += dentry->d_name.len * 2;
-                ret = btrfs_update_inode(trans, btrfs_sb(inode->i_sb),
+                ret = btrfs_update_inode(trans, root,
                                          dentry->d_parent->d_inode);
         }
         check_inode(inode);
@@ -710,7 +807,7 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry,
                         int mode, struct nameidata *nd)
 {
         struct btrfs_trans_handle *trans;
-        struct btrfs_root *root = btrfs_sb(dir->i_sb);
+        struct btrfs_root *root = BTRFS_I(dir)->root;
         struct inode *inode;
         int err;
         int drop_inode = 0;
@@ -747,18 +844,26 @@ out_unlock:
 static int btrfs_make_empty_dir(struct btrfs_trans_handle *trans,
                                 struct inode *inode, struct inode *dir)
 {
-        struct btrfs_root *root = btrfs_sb(inode->i_sb);
+        struct btrfs_root *root = BTRFS_I(dir)->root;
         int ret;
         char buf[2];
+        struct btrfs_key key;
+
         buf[0] = '.';
         buf[1] = '.';
 
+        key.objectid = inode->i_ino;
+        key.offset = 0;
+        key.flags = 0;
+        btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
+
         ret = btrfs_insert_dir_item(trans, root, buf, 1, inode->i_ino,
-                                    inode->i_ino, 1);
+                                    &key, 1);
         if (ret)
                 goto error;
+        key.objectid = dir->i_ino;
         ret = btrfs_insert_dir_item(trans, root, buf, 2, inode->i_ino,
-                                    dir->i_ino, 1);
+                                    &key, 1);
         if (ret)
                 goto error;
         inode->i_size = 6;
@@ -771,7 +876,7 @@ static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 {
         struct inode *inode;
         struct btrfs_trans_handle *trans;
-        struct btrfs_root *root = btrfs_sb(dir->i_sb);
+        struct btrfs_root *root = BTRFS_I(dir)->root;
         int err = 0;
         int drop_on_err = 0;
 
@@ -910,7 +1015,7 @@ static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,
         u64 extent_end = 0;
         u64 objectid = inode->i_ino;
         struct btrfs_path *path;
-        struct btrfs_root *root = btrfs_sb(inode->i_sb);
+        struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_trans_handle *trans = NULL;
         struct btrfs_file_extent_item *item;
         struct btrfs_leaf *leaf;
@@ -999,7 +1104,7 @@ static int btrfs_get_block(struct inode *inode, sector_t iblock,
                            struct buffer_head *result, int create)
 {
         int err;
-        struct btrfs_root *root = btrfs_sb(inode->i_sb);
+        struct btrfs_root *root = BTRFS_I(inode)->root;
         mutex_lock(&root->fs_info->fs_mutex);
         err = btrfs_get_block_lock(inode, iblock, result, create);
         // err = btrfs_get_block_inline(inode, iblock, result, create);
@@ -1041,7 +1146,7 @@ static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
 
 static void btrfs_truncate(struct inode *inode)
 {
-        struct btrfs_root *root = btrfs_sb(inode->i_sb);
+        struct btrfs_root *root = BTRFS_I(inode)->root;
         int ret;
         struct btrfs_trans_handle *trans;
 
@@ -1208,7 +1313,7 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
         int err = 0;
         int ret = 0;
         struct inode *inode = file->f_path.dentry->d_inode;
-        struct btrfs_root *root = btrfs_sb(inode->i_sb);
+        struct btrfs_root *root = BTRFS_I(inode)->root;
         struct page *pages[1];
 
         if (file->f_flags & O_DIRECT)
@@ -1365,7 +1470,7 @@ static ssize_t btrfs_file_inline_write(struct file *file,
         int err = 0;
         int ret = 0;
         struct inode *inode = file->f_path.dentry->d_inode;
-        struct btrfs_root *root = btrfs_sb(inode->i_sb);
+        struct btrfs_root *root = BTRFS_I(inode)->root;
         unsigned long page_index;
 
         if (file->f_flags & O_DIRECT)
@@ -1432,13 +1537,14 @@ static int btrfs_read_actor(read_descriptor_t *desc, struct page *page,
 {
         char *kaddr;
         unsigned long left, count = desc->count;
+        struct inode *inode = page->mapping->host;
 
         if (size > count)
                 size = count;
 
         if (!PageChecked(page)) {
                 /* FIXME, do it per block */
-                struct btrfs_root *root = btrfs_sb(page->mapping->host->i_sb);
+                struct btrfs_root *root = BTRFS_I(inode)->root;
                 int ret = btrfs_csum_verify_file_block(root,
                                           page->mapping->host->i_ino,
                                           page->index << PAGE_CACHE_SHIFT,
@@ -1662,6 +1768,10 @@ static struct inode_operations btrfs_dir_inode_operations = {
         .rmdir          = btrfs_rmdir,
 };
 
+static struct inode_operations btrfs_dir_ro_inode_operations = {
+        .lookup         = btrfs_lookup,
+};
+
 static struct file_operations btrfs_dir_file_operations = {
         .llseek         = generic_file_llseek,
         .read           = generic_read_dir,
@@ -1697,13 +1807,21 @@ static int __init init_btrfs_fs(void)
         err = init_inodecache();
         if (err)
                 return err;
+        kset_set_kset_s(&btrfs_subsys, fs_subsys);
+        err = subsystem_register(&btrfs_subsys);
+        if (err)
+                goto out;
         return register_filesystem(&btrfs_fs_type);
+out:
+        destroy_inodecache();
+        return err;
 }
 
 static void __exit exit_btrfs_fs(void)
 {
         destroy_inodecache();
         unregister_filesystem(&btrfs_fs_type);
+        subsystem_unregister(&btrfs_subsys);
         printk("btrfs unloaded\n");
 }
 
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 2b0f98c92123..20d84bd03223 100644
--- a/fs/btrfs/transaction.c
+++ b/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");