Btrfs: groundwork for subvolume and snapshot roots
authorChris Mason <chris.mason@oracle.com>
Mon, 9 Apr 2007 14:42:37 +0000 (10:42 -0400)
committerDavid Woodhouse <dwmw2@hera.kernel.org>
Mon, 9 Apr 2007 14:42:37 +0000 (10:42 -0400)
Signed-off-by: Chris Mason <chris.mason@oracle.com>
fs/btrfs/bit-radix.c
fs/btrfs/ctree.h
fs/btrfs/disk-io.c
fs/btrfs/disk-io.h
fs/btrfs/super.c
fs/btrfs/transaction.c

index 783f54c2a16cf0abde87ce382cef4de994f138ce..9fc42e99c7dfd526d707bda1f0755471b6178ba2 100644 (file)
@@ -86,7 +86,7 @@ int find_first_radix_bit(struct radix_tree_root *radix, unsigned long *retbits,
        int i;
        int total_found = 0;
 
-       ret = radix_tree_gang_lookup(radix, (void *)&gang, 0, ARRAY_SIZE(gang));
+       ret = radix_tree_gang_lookup(radix, (void **)gang, 0, ARRAY_SIZE(gang));
        for (i = 0; i < ret && nr > 0; i++) {
                found = 0;
                bits = gang[i];
index 1ff5b99af682350856956a19fbd2a4c82792a84f..5460030c9e6afa743cfd00eff19b6ea41cf725cf 100644 (file)
@@ -232,12 +232,12 @@ struct btrfs_inode_map_item {
 
 struct crypto_hash;
 struct btrfs_fs_info {
-       struct btrfs_root *fs_root;
        struct btrfs_root *extent_root;
        struct btrfs_root *tree_root;
        struct btrfs_root *inode_root;
        struct btrfs_key current_insert;
        struct btrfs_key last_insert;
+       struct radix_tree_root fs_roots_radix;
        struct radix_tree_root pending_del_radix;
        struct radix_tree_root pinned_radix;
        u64 last_inode_alloc;
@@ -266,6 +266,9 @@ struct btrfs_root {
        struct btrfs_root_item root_item;
        struct btrfs_key root_key;
        struct btrfs_fs_info *fs_info;
+       struct inode *inode;
+       u64 objectid;
+       u64 last_trans;
        u32 blocksize;
        int ref_cows;
        u32 type;
@@ -595,7 +598,7 @@ static inline u32 btrfs_key_overflow(struct btrfs_key *key)
 
 static inline void btrfs_set_key_overflow(struct btrfs_key *key, u32 over)
 {
-       BUG_ON(over > BTRFS_KEY_OVERFLOW_MAX);
+       BUG_ON(over >= BTRFS_KEY_OVERFLOW_MAX);
        over = over << BTRFS_KEY_OVERFLOW_SHIFT;
        key->flags = (key->flags & ~((u64)BTRFS_KEY_OVERFLOW_MASK)) | over;
 }
@@ -634,7 +637,7 @@ static inline void btrfs_set_disK_key_overflow(struct btrfs_disk_key *key,
                                               u32 over)
 {
        u32 flags = btrfs_disk_key_flags(key);
-       BUG_ON(over > BTRFS_KEY_OVERFLOW_MAX);
+       BUG_ON(over >= BTRFS_KEY_OVERFLOW_MAX);
        over = over << BTRFS_KEY_OVERFLOW_SHIFT;
        flags = (flags & ~((u64)BTRFS_KEY_OVERFLOW_MASK)) | over;
        btrfs_set_disk_key_flags(key, flags);
@@ -748,6 +751,17 @@ static inline void btrfs_set_super_blocknr(struct btrfs_super_block *s, u64 val)
        s->blocknr = cpu_to_le64(val);
 }
 
+static inline u64 btrfs_super_generation(struct btrfs_super_block *s)
+{
+       return le64_to_cpu(s->generation);
+}
+
+static inline void btrfs_set_super_generation(struct btrfs_super_block *s,
+                                             u64 val)
+{
+       s->generation = cpu_to_le64(val);
+}
+
 static inline u64 btrfs_super_root(struct btrfs_super_block *s)
 {
        return le64_to_cpu(s->root);
index b9301a5e4608506b2f6701eabca7d847a67bffb1..b557bdd1e26a44eff04cec1034e0eeb384413e85 100644 (file)
@@ -4,9 +4,11 @@
 #include <linux/crypto.h>
 #include <linux/scatterlist.h>
 #include <linux/swap.h>
+#include <linux/radix-tree.h>
 #include "ctree.h"
 #include "disk-io.h"
 #include "transaction.h"
+#include "btrfs_inode.h"
 
 static int check_tree_block(struct btrfs_root *root, struct buffer_head *buf)
 {
@@ -180,7 +182,7 @@ static int csum_tree_block(struct btrfs_root *root, struct buffer_head *bh,
 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 {
        struct buffer_head *bh;
-       struct btrfs_root *root = btrfs_sb(page->mapping->host->i_sb);
+       struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
        struct buffer_head *head;
        if (!page_has_buffers(page)) {
                create_empty_buffers(page, root->fs_info->sb->s_blocksize,
@@ -259,10 +261,13 @@ static int __setup_root(int blocksize,
                        u64 objectid)
 {
        root->node = NULL;
+       root->inode = NULL;
        root->commit_root = NULL;
        root->blocksize = blocksize;
        root->ref_cows = 0;
        root->fs_info = fs_info;
+       root->objectid = objectid;
+       root->last_trans = 0;
        memset(&root->root_key, 0, sizeof(root->root_key));
        memset(&root->root_item, 0, sizeof(root->root_item));
        return 0;
@@ -287,10 +292,78 @@ static int find_and_setup_root(int blocksize,
        return 0;
 }
 
+struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
+                                     struct btrfs_key *location)
+{
+       struct btrfs_root *root;
+       struct btrfs_root *tree_root = fs_info->tree_root;
+       struct btrfs_path *path;
+       struct btrfs_leaf *l;
+       int ret = 0;
+
+printk("read_fs_root looking for %Lu %Lu %u\n", location->objectid, location->offset, location->flags);
+       root = kmalloc(sizeof(*root), GFP_NOFS);
+       if (!root) {
+printk("failed1\n");
+               return ERR_PTR(-ENOMEM);
+       }
+       if (location->offset == (u64)-1) {
+               ret = find_and_setup_root(fs_info->sb->s_blocksize,
+                                         fs_info->tree_root, fs_info,
+                                         location->objectid, root);
+               if (ret) {
+printk("failed2\n");
+                       kfree(root);
+                       return ERR_PTR(ret);
+               }
+               goto insert;
+       }
+
+       __setup_root(fs_info->sb->s_blocksize, root, fs_info,
+                    location->objectid);
+
+       path = btrfs_alloc_path();
+       BUG_ON(!path);
+       ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
+       if (ret != 0) {
+printk("internal search_slot gives us %d\n", ret);
+               if (ret > 0)
+                       ret = -ENOENT;
+               goto out;
+       }
+       l = btrfs_buffer_leaf(path->nodes[0]);
+       memcpy(&root->root_item,
+              btrfs_item_ptr(l, path->slots[0], struct btrfs_root_item),
+              sizeof(root->root_item));
+       memcpy(&root->root_key, location, sizeof(*location));
+       ret = 0;
+out:
+       btrfs_release_path(root, path);
+       btrfs_free_path(path);
+       if (ret) {
+               kfree(root);
+               return ERR_PTR(ret);
+       }
+       root->node = read_tree_block(root,
+                                    btrfs_root_blocknr(&root->root_item));
+       BUG_ON(!root->node);
+insert:
+printk("inserting %p\n", root);
+       root->ref_cows = 1;
+       ret = radix_tree_insert(&fs_info->fs_roots_radix, (unsigned long)root,
+                               root);
+       if (ret) {
+printk("radix_tree_insert gives us %d\n", ret);
+               brelse(root->node);
+               kfree(root);
+               return ERR_PTR(ret);
+       }
+printk("all worked\n");
+       return root;
+}
+
 struct btrfs_root *open_ctree(struct super_block *sb)
 {
-       struct btrfs_root *root = kmalloc(sizeof(struct btrfs_root),
-                                         GFP_NOFS);
        struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
                                                 GFP_NOFS);
        struct btrfs_root *tree_root = kmalloc(sizeof(struct btrfs_root),
@@ -304,9 +377,9 @@ struct btrfs_root *open_ctree(struct super_block *sb)
 
        init_bit_radix(&fs_info->pinned_radix);
        init_bit_radix(&fs_info->pending_del_radix);
+       INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
        sb_set_blocksize(sb, 4096);
        fs_info->running_transaction = NULL;
-       fs_info->fs_root = root;
        fs_info->tree_root = tree_root;
        fs_info->extent_root = extent_root;
        fs_info->inode_root = inode_root;
@@ -318,6 +391,9 @@ struct btrfs_root *open_ctree(struct super_block *sb)
        fs_info->btree_inode->i_nlink = 1;
        fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
        fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
+       BTRFS_I(fs_info->btree_inode)->root = tree_root;
+       memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
+              sizeof(struct btrfs_key));
        insert_inode_hash(fs_info->btree_inode);
        mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
        fs_info->hash_tfm = crypto_alloc_hash("sha256", 0, CRYPTO_ALG_ASYNC);
@@ -337,13 +413,12 @@ struct btrfs_root *open_ctree(struct super_block *sb)
                                             BTRFS_SUPER_INFO_OFFSET /
                                             sb->s_blocksize);
 
-       if (!fs_info->sb_buffer) {
+       if (!fs_info->sb_buffer)
                return NULL;
-       }
        disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data;
-       if (!btrfs_super_root(disk_super)) {
+       if (!btrfs_super_root(disk_super))
                return NULL;
-       }
+
        fs_info->disk_super = disk_super;
        tree_root->node = read_tree_block(tree_root,
                                          btrfs_super_root(disk_super));
@@ -358,14 +433,8 @@ struct btrfs_root *open_ctree(struct super_block *sb)
                                  BTRFS_INODE_MAP_OBJECTID, inode_root);
        BUG_ON(ret);
 
-       ret = find_and_setup_root(sb->s_blocksize, tree_root, fs_info,
-                                 BTRFS_FS_TREE_OBJECTID, root);
-       BUG_ON(ret);
-       root->commit_root = root->node;
-       get_bh(root->node);
-       root->ref_cows = 1;
-       root->fs_info->generation = root->root_key.offset + 1;
-       ret = btrfs_find_highest_inode(root, &root->fs_info->last_inode_alloc);
+       fs_info->generation = btrfs_super_generation(disk_super) + 1;
+       ret = btrfs_find_highest_inode(tree_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));
@@ -373,7 +442,7 @@ struct btrfs_root *open_ctree(struct super_block *sb)
        kobject_set_name(&fs_info->kobj, "%s", sb->s_id);
        kobject_register(&fs_info->kobj);
        mutex_unlock(&fs_info->fs_mutex);
-       return root;
+       return tree_root;
 }
 
 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
@@ -398,12 +467,42 @@ int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
        return 0;
 }
 
+int del_fs_roots(struct btrfs_fs_info *fs_info)
+{
+       int ret;
+       struct btrfs_root *gang[8];
+       int i;
+
+       while(1) {
+               ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
+                                            (void **)gang, 0,
+                                            ARRAY_SIZE(gang));
+               if (!ret)
+                       break;
+               for (i = 0; i < ret; i++) {
+                       radix_tree_delete(&fs_info->fs_roots_radix,
+                                         (unsigned long)gang[i]);
+                       if (gang[i]->inode)
+                               iput(gang[i]->inode);
+                       else
+                               printk("no inode for root %p\n", gang[i]);
+                       if (gang[i]->node)
+                               brelse(gang[i]->node);
+                       if (gang[i]->commit_root)
+                               brelse(gang[i]->commit_root);
+                       kfree(gang[i]);
+               }
+       }
+       return 0;
+}
+
 int close_ctree(struct btrfs_root *root)
 {
        int ret;
        struct btrfs_trans_handle *trans;
+       struct btrfs_fs_info *fs_info = root->fs_info;
 
-       mutex_lock(&root->fs_info->fs_mutex);
+       mutex_lock(&fs_info->fs_mutex);
        trans = btrfs_start_transaction(root, 1);
        btrfs_commit_transaction(trans, root);
        /* run commit again to  drop the original snapshot */
@@ -412,29 +511,26 @@ int close_ctree(struct btrfs_root *root)
        ret = btrfs_write_and_wait_transaction(NULL, root);
        BUG_ON(ret);
        write_ctree_super(NULL, root);
-       mutex_unlock(&root->fs_info->fs_mutex);
-
-       if (root->node)
-               btrfs_block_release(root, root->node);
-       if (root->fs_info->extent_root->node)
-               btrfs_block_release(root->fs_info->extent_root,
-                                   root->fs_info->extent_root->node);
-       if (root->fs_info->inode_root->node)
-               btrfs_block_release(root->fs_info->inode_root,
-                                   root->fs_info->inode_root->node);
-       if (root->fs_info->tree_root->node)
-               btrfs_block_release(root->fs_info->tree_root,
-                                   root->fs_info->tree_root->node);
-       btrfs_block_release(root, root->commit_root);
-       btrfs_block_release(root, root->fs_info->sb_buffer);
-       crypto_free_hash(root->fs_info->hash_tfm);
-       truncate_inode_pages(root->fs_info->btree_inode->i_mapping, 0);
-       iput(root->fs_info->btree_inode);
-       kfree(root->fs_info->extent_root);
-       kfree(root->fs_info->inode_root);
-       kfree(root->fs_info->tree_root);
-       kobject_unregister(&root->fs_info->kobj);
-       kfree(root);
+       mutex_unlock(&fs_info->fs_mutex);
+
+       if (fs_info->extent_root->node)
+               btrfs_block_release(fs_info->extent_root,
+                                   fs_info->extent_root->node);
+       if (fs_info->inode_root->node)
+               btrfs_block_release(fs_info->inode_root,
+                                   fs_info->inode_root->node);
+       if (fs_info->tree_root->node)
+               btrfs_block_release(fs_info->tree_root,
+                                   fs_info->tree_root->node);
+       btrfs_block_release(root, fs_info->sb_buffer);
+       crypto_free_hash(fs_info->hash_tfm);
+       truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
+       iput(fs_info->btree_inode);
+       del_fs_roots(fs_info);
+       kfree(fs_info->extent_root);
+       kfree(fs_info->inode_root);
+       kfree(fs_info->tree_root);
+       kobject_unregister(&fs_info->kobj);
        return 0;
 }
 
index ac6764ba8aa61ff2e747cc4a466c5e83a18bea06..0ef6e6f714af6a691f6f3a08c17df92500de2627 100644 (file)
@@ -39,4 +39,6 @@ int write_ctree_super(struct btrfs_trans_handle *trans,
 struct buffer_head *btrfs_find_tree_block(struct btrfs_root *root, u64 blocknr);
 int btrfs_csum_data(struct btrfs_root * root, char *data, size_t len,
                    char *result);
+struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
+                                     struct btrfs_key *location);
 #endif
index 66d9fb2288c302511fbbfdf6529611a2fd53ea09..3c9236ca889c0aca801dc0213696b78fd5aba2bf 100644 (file)
@@ -436,7 +436,6 @@ int fixup_tree_root_location(struct btrfs_root *root,
 {
        struct btrfs_path *path;
        struct btrfs_root_item *ri;
-       int ret;
 
        if (btrfs_key_type(location) != BTRFS_ROOT_ITEM_KEY)
                return 0;
@@ -447,22 +446,19 @@ int fixup_tree_root_location(struct btrfs_root *root,
        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);
+       *sub_root = btrfs_read_fs_root(root->fs_info, location);
+       if (IS_ERR(*sub_root))
+               return PTR_ERR(*sub_root);
+
+       ri = &(*sub_root)->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;
+       return 0;
 }
 
 
@@ -494,6 +490,15 @@ static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
                if (!inode)
                        return ERR_PTR(-EACCES);
                if (inode->i_state & I_NEW) {
+                       if (sub_root != root) {
+                               ret = radix_tree_insert(
+                                               &root->fs_info->fs_roots_radix,
+                                               (unsigned long)sub_root,
+                                               sub_root);
+printk("adding new root for inode %lu\n", inode->i_ino);
+                               igrab(inode);
+                               sub_root->inode = inode;
+                       }
                        BTRFS_I(inode)->root = sub_root;
                        memcpy(&BTRFS_I(inode)->location, &location,
                               sizeof(location));
@@ -605,7 +610,7 @@ static int btrfs_fill_super(struct super_block * sb, void * data, int silent)
        struct inode * inode;
        struct dentry * root_dentry;
        struct btrfs_super_block *disk_super;
-       struct btrfs_root *root;
+       struct btrfs_root *tree_root;
        struct btrfs_inode *bi;
 
        sb->s_maxbytes = MAX_LFS_FILESIZE;
@@ -613,14 +618,14 @@ static int btrfs_fill_super(struct super_block * sb, void * data, int silent)
        sb->s_op = &btrfs_super_ops;
        sb->s_time_gran = 1;
 
-       root = open_ctree(sb);
+       tree_root = open_ctree(sb);
 
-       if (!root) {
+       if (!tree_root) {
                printk("btrfs: open_ctree failed\n");
                return -EIO;
        }
-       sb->s_fs_info = root;
-       disk_super = root->fs_info->disk_super;
+       sb->s_fs_info = tree_root;
+       disk_super = tree_root->fs_info->disk_super;
        printk("read in super total blocks %Lu root %Lu\n",
               btrfs_super_total_blocks(disk_super),
               btrfs_super_root_dir(disk_super));
@@ -630,7 +635,7 @@ static int btrfs_fill_super(struct super_block * sb, void * data, int silent)
        bi->location.objectid = inode->i_ino;
        bi->location.offset = 0;
        bi->location.flags = 0;
-       bi->root = root->fs_info->tree_root;
+       bi->root = tree_root;
        btrfs_set_key_type(&bi->location, BTRFS_INODE_ITEM_KEY);
 
        if (!inode)
index 20d84bd0322387a3a99f007f7f04cc2331cd6aa1..83a0194ab16310e5e7b998bbf8454c8b8b41f481 100644 (file)
@@ -8,6 +8,8 @@ static int total_trans = 0;
 extern struct kmem_cache *btrfs_trans_handle_cachep;
 extern struct kmem_cache *btrfs_transaction_cachep;
 
+#define BTRFS_ROOT_TRANS_TAG 0
+
 #define TRANS_MAGIC 0xE1E10E
 static void put_transaction(struct btrfs_transaction *transaction)
 {
@@ -31,9 +33,10 @@ static int join_transaction(struct btrfs_root *root)
                                             GFP_NOFS);
                total_trans++;
                BUG_ON(!cur_trans);
+               root->fs_info->generation++;
                root->fs_info->running_transaction = cur_trans;
                cur_trans->num_writers = 0;
-               cur_trans->transid = root->root_key.offset + 1;
+               cur_trans->transid = root->fs_info->generation;
                init_waitqueue_head(&cur_trans->writer_wait);
                init_waitqueue_head(&cur_trans->commit_wait);
                cur_trans->magic = TRANS_MAGIC;
@@ -51,13 +54,22 @@ struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
        struct btrfs_trans_handle *h =
                kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
        int ret;
+       u64 running_trans_id;
 
-       /* 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);
-       h->transid = root->fs_info->running_transaction->transid;
+       running_trans_id = root->fs_info->running_transaction->transid;
+
+       if (root != root->fs_info->tree_root && root->last_trans <
+           running_trans_id) {
+               radix_tree_tag_set(&root->fs_info->fs_roots_radix,
+                                  (unsigned long)root, BTRFS_ROOT_TRANS_TAG);
+               root->commit_root = root->node;
+               get_bh(root->node);
+       }
+       root->last_trans = running_trans_id;
+       h->transid = running_trans_id;
        h->transaction = root->fs_info->running_transaction;
        h->blocks_reserved = num_blocks;
        h->blocks_used = 0;
@@ -72,9 +84,6 @@ int btrfs_end_transaction(struct btrfs_trans_handle *trans,
 {
        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);
@@ -145,17 +154,96 @@ static int wait_for_commit(struct btrfs_root *root,
        return 0;
 }
 
+struct dirty_root {
+       struct list_head list;
+       struct btrfs_key snap_key;
+       struct buffer_head *commit_root;
+       struct btrfs_root *root;
+};
+
+int add_dirty_roots(struct btrfs_trans_handle *trans,
+                   struct radix_tree_root *radix, struct list_head *list)
+{
+       struct dirty_root *dirty;
+       struct btrfs_root *gang[8];
+       struct btrfs_root *root;
+       int i;
+       int ret;
+       int err;
+printk("add dirty\n");
+       while(1) {
+               ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
+                                                ARRAY_SIZE(gang),
+                                                BTRFS_ROOT_TRANS_TAG);
+               if (ret == 0)
+                       break;
+               for (i = 0; i < ret; i++) {
+                       root = gang[i];
+                       radix_tree_tag_clear(radix, (unsigned long)root,
+                                            BTRFS_ROOT_TRANS_TAG);
+                       if (root->commit_root == root->node) {
+                               WARN_ON(root->node->b_blocknr !=
+                                       btrfs_root_blocknr(&root->root_item));
+                               brelse(root->commit_root);
+                               root->commit_root = NULL;
+                               continue;
+                       }
+                       dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
+                       BUG_ON(!dirty);
+                       memcpy(&dirty->snap_key, &root->root_key,
+                              sizeof(root->root_key));
+                       dirty->commit_root = root->commit_root;
+                       root->commit_root = NULL;
+                       dirty->root = root;
+printk("adding dirty root %Lu gen %Lu blocknr %Lu\n", root->root_key.objectid, root->root_key.offset, dirty->commit_root->b_blocknr);
+                       root->root_key.offset = root->fs_info->generation;
+                       btrfs_set_root_blocknr(&root->root_item,
+                                              root->node->b_blocknr);
+                       err = btrfs_insert_root(trans, root->fs_info->tree_root,
+                                               &root->root_key,
+                                               &root->root_item);
+                       BUG_ON(err);
+                       list_add(&dirty->list, list);
+               }
+       }
+printk("add dirty done\n");
+       return 0;
+}
+
+int drop_dirty_roots(struct btrfs_root *tree_root, struct list_head *list)
+{
+       struct dirty_root *dirty;
+       struct btrfs_trans_handle *trans;
+       int ret;
+
+       while(!list_empty(list)) {
+               dirty = list_entry(list->next, struct dirty_root, list);
+               list_del_init(&dirty->list);
+               trans = btrfs_start_transaction(tree_root, 1);
+printk("drop snapshot root %p, commit_root blocknr %Lu generation %Lu\n", dirty->root, dirty->commit_root->b_blocknr, dirty->snap_key.offset);
+               ret = btrfs_drop_snapshot(trans, dirty->root,
+                                         dirty->commit_root);
+               BUG_ON(ret);
+
+printk("del root objectid %Lu, offset %Lu\n", dirty->snap_key.objectid, dirty->snap_key.offset);
+               ret = btrfs_del_root(trans, tree_root, &dirty->snap_key);
+               BUG_ON(ret);
+               ret = btrfs_end_transaction(trans, tree_root);
+               BUG_ON(ret);
+               kfree(dirty);
+       }
+       return 0;
+}
+
 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                             struct btrfs_root *root)
 {
        int ret = 0;
-       struct buffer_head *snap;
-       struct btrfs_key snap_key;
        struct btrfs_transaction *cur_trans;
+       struct list_head dirty_fs_roots;
        DEFINE_WAIT(wait);
 
-       /* FIXME, use the right root */
-       root = root->fs_info->fs_root;
+       INIT_LIST_HEAD(&dirty_fs_roots);
 
        mutex_lock(&root->fs_info->trans_mutex);
        if (trans->transaction->in_commit) {
@@ -184,22 +272,13 @@ printk("already in commit!, waiting\n");
        }
        finish_wait(&trans->transaction->writer_wait, &wait);
        WARN_ON(cur_trans != trans->transaction);
-       if (root->node != root->commit_root) {
-               memcpy(&snap_key, &root->root_key, sizeof(snap_key));
-               root->root_key.offset++;
-       }
-
-       if (btrfs_root_blocknr(&root->root_item) != root->node->b_blocknr) {
-               btrfs_set_root_blocknr(&root->root_item, root->node->b_blocknr);
-               ret = btrfs_insert_root(trans, root->fs_info->tree_root,
-                                       &root->root_key, &root->root_item);
-               BUG_ON(ret);
-       }
-
+       add_dirty_roots(trans, &root->fs_info->fs_roots_radix, &dirty_fs_roots);
        ret = btrfs_commit_tree_roots(trans, root);
        BUG_ON(ret);
        cur_trans = root->fs_info->running_transaction;
        root->fs_info->running_transaction = NULL;
+       btrfs_set_super_generation(root->fs_info->disk_super,
+                                  root->fs_info->generation + 1);
        mutex_unlock(&root->fs_info->trans_mutex);
        ret = btrfs_write_and_wait_transaction(trans, root);
        BUG_ON(ret);
@@ -213,21 +292,8 @@ printk("already in commit!, waiting\n");
        put_transaction(cur_trans);
        mutex_unlock(&root->fs_info->trans_mutex);
        kmem_cache_free(btrfs_trans_handle_cachep, trans);
-       if (root->node != root->commit_root) {
-               trans = btrfs_start_transaction(root, 1);
-               snap = root->commit_root;
-               root->commit_root = root->node;
-               get_bh(root->node);
-               ret = btrfs_drop_snapshot(trans, root, snap);
-               BUG_ON(ret);
 
-               ret = btrfs_del_root(trans, root->fs_info->tree_root,
-                                    &snap_key);
-               BUG_ON(ret);
-               root->fs_info->generation = root->root_key.offset + 1;
-               ret = btrfs_end_transaction(trans, root);
-               BUG_ON(ret);
-       }
+       drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
        return ret;
 }