Btrfs: groundwork for subvolume and snapshot roots

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

1 files changed, 137 insertions, 41 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index b9301a5e4608..b557bdd1e26a 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -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;
 }