Btrfs: reference counts on data extents

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

diff --git a/fs/btrfs/TODO b/fs/btrfs/TODO
index 2ca301b..7aec75e 100644 (file)
--- a/fs/btrfs/TODO
+++ b/fs/btrfs/TODO
@@ -8,7 +8,10 @@
 * Add block mapping tree (simple dm layer)
 * Add simple tree locking (semaphore per tree)
 * Make allocator smarter
+* make level a field in header
+* add a block group to struct inode
 * Make directory hashing work on 32 bit
+* Make sure nobh stuff is working properly for cows
 * Do actual block accounting
 * Check compat and incompat flags on the inode
 * Add virtual filesystems, mountable snapshots

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 7b7120d..1a98952 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -9,10 +9,11 @@ struct btrfs_transaction;
 
 #define BTRFS_MAGIC "_BtRfS_M"
 
-#define BTRFS_ROOT_TREE_OBJECTID 1
-#define BTRFS_EXTENT_TREE_OBJECTID 2
-#define BTRFS_INODE_MAP_OBJECTID 3
-#define BTRFS_FS_TREE_OBJECTID 4
+#define BTRFS_ROOT_TREE_OBJECTID 1ULL
+#define BTRFS_EXTENT_TREE_OBJECTID 2ULL
+#define BTRFS_INODE_MAP_OBJECTID 3ULL
+#define BTRFS_FS_TREE_OBJECTID 4ULL
+#define BTRFS_FIRST_FREE_OBJECTID 5ULL
 
 /*
  * we can actually store much bigger names, but lets not confuse the rest

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 82f6e9e..4d4fc48 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -13,7 +13,7 @@ static int del_pending_extents(struct btrfs_trans_handle *trans, struct
                               btrfs_root *extent_root);
 
 static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
-                        *root, u64 blocknr)
+                        *root, u64 blocknr, u64 num_blocks)
 {
        struct btrfs_path path;
        int ret;
@@ -29,7 +29,7 @@ static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
        key.objectid = blocknr;
        key.flags = 0;
        btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
-       key.offset = 1;
+       key.offset = num_blocks;
        ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, &path,
                                0, 1);
        if (ret != 0)
@@ -48,7 +48,7 @@ static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
 }
 
 static int lookup_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
-                           *root, u64 blocknr, u32 *refs)
+                           *root, u64 blocknr, u64 num_blocks, u32 *refs)
 {
        struct btrfs_path path;
        int ret;
@@ -57,7 +57,7 @@ static int lookup_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
        struct btrfs_extent_item *item;
        btrfs_init_path(&path);
        key.objectid = blocknr;
-       key.offset = 1;
+       key.offset = num_blocks;
        key.flags = 0;
        btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
        ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, &path,
@@ -76,17 +76,34 @@ int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 {
        u64 blocknr;
        struct btrfs_node *buf_node;
+       struct btrfs_leaf *buf_leaf;
+       struct btrfs_disk_key *key;
+       struct btrfs_file_extent_item *fi;
        int i;
+       int leaf;
+       int ret;
 
        if (!root->ref_cows)
                return 0;
        buf_node = btrfs_buffer_node(buf);
-       if (btrfs_is_leaf(buf_node))
-               return 0;
-
+       leaf = btrfs_is_leaf(buf_node);
+       buf_leaf = btrfs_buffer_leaf(buf);
        for (i = 0; i < btrfs_header_nritems(&buf_node->header); i++) {
-               blocknr = btrfs_node_blockptr(buf_node, i);
-               inc_block_ref(trans, root, blocknr);
+               if (leaf) {
+                       key = &buf_leaf->items[i].key;
+                       if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
+                               continue;
+                       fi = btrfs_item_ptr(buf_leaf, i,
+                                           struct btrfs_file_extent_item);
+                       ret = inc_block_ref(trans, root,
+                                   btrfs_file_extent_disk_blocknr(fi),
+                                   btrfs_file_extent_disk_num_blocks(fi));
+                       BUG_ON(ret);
+               } else {
+                       blocknr = btrfs_node_blockptr(buf_node, i);
+                       ret = inc_block_ref(trans, root, blocknr, 1);
+                       BUG_ON(ret);
+               }
        }
        return 0;
 }
@@ -469,6 +486,37 @@ struct buffer_head *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
        return buf;
 }
 
+static int drop_leaf_ref(struct btrfs_trans_handle *trans,
+                        struct btrfs_root *root, struct buffer_head *cur)
+{
+       struct btrfs_disk_key *key;
+       struct btrfs_leaf *leaf;
+       struct btrfs_file_extent_item *fi;
+       int i;
+       int nritems;
+       int ret;
+
+       BUG_ON(!btrfs_is_leaf(btrfs_buffer_node(cur)));
+       leaf = btrfs_buffer_leaf(cur);
+       nritems = btrfs_header_nritems(&leaf->header);
+       for (i = 0; i < nritems; i++) {
+               key = &leaf->items[i].key;
+               if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
+                       continue;
+               fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
+               /*
+                * FIXME make sure to insert a trans record that
+                * repeats the snapshot del on crash
+                */
+               ret = btrfs_free_extent(trans, root,
+                                       btrfs_file_extent_disk_blocknr(fi),
+                                       btrfs_file_extent_disk_num_blocks(fi),
+                                       0);
+               BUG_ON(ret);
+       }
+       return 0;
+}
+
 /*
  * helper function for drop_snapshot, this walks down the tree dropping ref
  * counts as it goes.
@@ -483,28 +531,33 @@ static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
        u32 refs;
 
        ret = lookup_block_ref(trans, root, path->nodes[*level]->b_blocknr,
-                              &refs);
+                              1, &refs);
        BUG_ON(ret);
        if (refs > 1)
                goto out;
        /*
         * walk down to the last node level and free all the leaves
         */
-       while(*level > 0) {
+       while(*level >= 0) {
                cur = path->nodes[*level];
                if (path->slots[*level] >=
                    btrfs_header_nritems(btrfs_buffer_header(cur)))
                        break;
+               if (*level == 0) {
+                       ret = drop_leaf_ref(trans, root, cur);
+                       BUG_ON(ret);
+                       break;
+               }
                blocknr = btrfs_node_blockptr(btrfs_buffer_node(cur),
                                              path->slots[*level]);
-               ret = lookup_block_ref(trans, root, blocknr, &refs);
-               if (refs != 1 || *level == 1) {
+               ret = lookup_block_ref(trans, root, blocknr, 1, &refs);
+               BUG_ON(ret);
+               if (refs != 1) {
                        path->slots[*level]++;
                        ret = btrfs_free_extent(trans, root, blocknr, 1, 1);
                        BUG_ON(ret);
                        continue;
                }
-               BUG_ON(ret);
                next = read_tree_block(root, blocknr);
                if (path->nodes[*level-1])
                        btrfs_block_release(root, path->nodes[*level-1]);
@@ -513,8 +566,8 @@ static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
                path->slots[*level] = 0;
        }
 out:
-       ret = btrfs_free_extent(trans, root, path->nodes[*level]->b_blocknr,
-                               1, 1);
+       ret = btrfs_free_extent(trans, root,
+                               path->nodes[*level]->b_blocknr, 1, 1);
        btrfs_block_release(root, path->nodes[*level]);
        path->nodes[*level] = NULL;
        *level += 1;
@@ -544,10 +597,10 @@ static int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root
                        ret = btrfs_free_extent(trans, root,
                                                path->nodes[*level]->b_blocknr,
                                                1, 1);
+                       BUG_ON(ret);
                        btrfs_block_release(root, path->nodes[*level]);
                        path->nodes[*level] = NULL;
                        *level = i + 1;
-                       BUG_ON(ret);
                }
        }
        return 1;

diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index ad2d375..1b2c5e0 100644 (file)
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -25,6 +25,7 @@ int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
        if (fs_root->fs_info->last_inode_alloc_dirid == dirid)
                search_start = fs_root->fs_info->last_inode_alloc;
 
+       search_start = max(search_start, BTRFS_FIRST_FREE_OBJECTID);
        search_key.objectid = search_start;
        search_key.flags = 0;
        btrfs_set_key_type(&search_key, BTRFS_INODE_MAP_ITEM_KEY);

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 2c2883f..487da5a 100644 (file)
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -700,7 +700,7 @@ out:
 static int btrfs_prepare_write(struct file *file, struct page *page,
                               unsigned from, unsigned to)
 {
-       return block_prepare_write(page, from, to, btrfs_get_block);
+       return nobh_prepare_write(page, from, to, btrfs_get_block);
 }
 
 static void btrfs_write_super(struct super_block *sb)
@@ -721,7 +721,7 @@ static int btrfs_readpages(struct file *file, struct address_space *mapping,
 
 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
 {
-       return block_write_full_page(page, btrfs_get_block, wbc);
+       return nobh_writepage(page, btrfs_get_block, wbc);
 }
 
 static int btrfs_get_sb(struct file_system_type *fs_type,
@@ -768,7 +768,7 @@ static struct address_space_operations btrfs_aops = {
        .writepage      = btrfs_writepage,
        .sync_page      = block_sync_page,
        .prepare_write  = btrfs_prepare_write,
-       .commit_write   = generic_commit_write,
+       .commit_write   = nobh_commit_write,
 };
 
 static struct inode_operations btrfs_file_inode_operations = {