Btrfs: Change the super to point to a tree of trees to enable persistent snapshots
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index f853220..13ed631 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -2,7 +2,8 @@
CC=gcc
CFLAGS = -g -Wall
headers = radix-tree.h ctree.h disk-io.h kerncompat.h print-tree.h list.h
-objects = ctree.o disk-io.o radix-tree.o mkfs.o extent-tree.o print-tree.o
+objects = ctree.o disk-io.o radix-tree.o mkfs.o extent-tree.o print-tree.o \
+ root-tree.o
# if you don't have sparse installed, use ls instead
CHECKFLAGS=-D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ -Wbitwise \
diff --git a/fs/btrfs/TODO b/fs/btrfs/TODO
index ad29267..ff90e5e 100644
--- a/fs/btrfs/TODO
+++ b/fs/btrfs/TODO
@@ -5,6 +5,7 @@
* make a real mkfs and superblock
* Do checksumming
* Define FS objects in terms of different item types
+* add inode tree
* Add block mapping tree (simple dm layer)
* Add simple tree locking (semaphore per tree)
* Make allocator smarter
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 5dfcc90..0968899 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -4,8 +4,13 @@
#include "list.h"
#include "kerncompat.h"
+#define BTRFS_MAGIC "_BtRfS_M"
#define BTRFS_BLOCKSIZE 1024
+#define BTRFS_ROOT_TREE_OBJECTID 1
+#define BTRFS_EXTENT_TREE_OBJECTID 2
+#define BTRFS_FS_TREE_OBJECTID 3
+
/*
* the key defines the order in the tree, and so it also defines (optimal)
* block layout. objectid corresonds to the inode number. The flags
@@ -36,7 +41,7 @@
* every tree block (leaf or node) starts with this header.
*/
struct btrfs_header {
- __le64 fsid[2]; /* FS specific uuid */
+ u8 fsid[16]; /* FS specific uuid */
__le64 blocknr; /* which block this node is supposed to live in */
__le64 parentid; /* objectid of the tree root */
__le32 csum;
@@ -52,6 +57,14 @@
struct btrfs_buffer;
+struct btrfs_root_item {
+ __le64 blocknr;
+ __le32 flags;
+ __le64 block_limit;
+ __le64 blocks_used;
+ __le32 refs;
+};
+
/*
* in ram representation of the tree. extent_root is used for all allocations
* and for the extent tree extent_root root. current_insert is used
@@ -61,6 +74,7 @@
struct btrfs_buffer *node;
struct btrfs_buffer *commit_root;
struct btrfs_root *extent_root;
+ struct btrfs_root *tree_root;
struct btrfs_key current_insert;
struct btrfs_key last_insert;
int fp;
@@ -69,28 +83,25 @@
struct list_head trans;
struct list_head cache;
int cache_size;
+ int ref_cows;
+ struct btrfs_root_item root_item;
+ struct btrfs_key root_key;
};
/*
- * describes a tree on disk
- */
-struct btrfs_root_info {
- u64 fsid[2]; /* FS specific uuid */
- u64 blocknr; /* blocknr of this block */
- u64 objectid; /* inode number of this root */
- u64 tree_root; /* the tree root block */
- u32 csum;
- u32 ham;
- u64 snapuuid[2]; /* root specific uuid */
-} __attribute__ ((__packed__));
-
-/*
* the super block basically lists the main trees of the FS
* it currently lacks any block count etc etc
*/
struct btrfs_super_block {
- struct btrfs_root_info root_info;
- struct btrfs_root_info extent_info;
+ u8 fsid[16]; /* FS specific uuid */
+ __le64 blocknr; /* this block number */
+ __le32 csum;
+ __le64 magic;
+ __le16 blocksize;
+ __le64 generation;
+ __le64 root;
+ __le64 total_blocks;
+ __le64 blocks_used;
} __attribute__ ((__packed__));
/*
@@ -317,6 +328,79 @@
return (btrfs_header_level(&n->header) == 0);
}
+static inline u64 btrfs_root_blocknr(struct btrfs_root_item *item)
+{
+ return le64_to_cpu(item->blocknr);
+}
+
+static inline void btrfs_set_root_blocknr(struct btrfs_root_item *item, u64 val)
+{
+ item->blocknr = cpu_to_le64(val);
+}
+
+static inline u32 btrfs_root_refs(struct btrfs_root_item *item)
+{
+ return le32_to_cpu(item->refs);
+}
+
+static inline void btrfs_set_root_refs(struct btrfs_root_item *item, u32 val)
+{
+ item->refs = cpu_to_le32(val);
+}
+
+static inline u64 btrfs_super_blocknr(struct btrfs_super_block *s)
+{
+ return le64_to_cpu(s->blocknr);
+}
+
+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_root(struct btrfs_super_block *s)
+{
+ return le64_to_cpu(s->root);
+}
+
+static inline void btrfs_set_super_root(struct btrfs_super_block *s, u64 val)
+{
+ s->root = cpu_to_le64(val);
+}
+
+static inline u64 btrfs_super_total_blocks(struct btrfs_super_block *s)
+{
+ return le64_to_cpu(s->total_blocks);
+}
+
+static inline void btrfs_set_super_total_blocks(struct btrfs_super_block *s,
+ u64 val)
+{
+ s->total_blocks = cpu_to_le64(val);
+}
+
+static inline u64 btrfs_super_blocks_used(struct btrfs_super_block *s)
+{
+ return le64_to_cpu(s->blocks_used);
+}
+
+static inline void btrfs_set_super_blocks_used(struct btrfs_super_block *s,
+ u64 val)
+{
+ s->blocks_used = cpu_to_le64(val);
+}
+
+static inline u16 btrfs_super_blocksize(struct btrfs_super_block *s)
+{
+ return le16_to_cpu(s->blocksize);
+}
+
+static inline void btrfs_set_super_blocksize(struct btrfs_super_block *s,
+ u16 val)
+{
+ s->blocksize = cpu_to_le16(val);
+}
+
struct btrfs_buffer *btrfs_alloc_free_block(struct btrfs_root *root);
int btrfs_inc_ref(struct btrfs_root *root, struct btrfs_buffer *buf);
int btrfs_free_extent(struct btrfs_root *root, u64 blocknr, u64 num_blocks);
@@ -331,4 +415,11 @@
int btrfs_leaf_free_space(struct btrfs_leaf *leaf);
int btrfs_drop_snapshot(struct btrfs_root *root, struct btrfs_buffer *snap);
int btrfs_finish_extent_commit(struct btrfs_root *root);
+int btrfs_del_root(struct btrfs_root *root, struct btrfs_key *key);
+int btrfs_insert_root(struct btrfs_root *root, struct btrfs_key *key,
+ struct btrfs_root_item *item);
+int btrfs_update_root(struct btrfs_root *root, struct btrfs_key *key,
+ struct btrfs_root_item *item);
+int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
+ struct btrfs_root_item *item, struct btrfs_key *key);
#endif
diff --git a/fs/btrfs/debug-tree.c b/fs/btrfs/debug-tree.c
index 6da0a7a..de45fb4 100644
--- a/fs/btrfs/debug-tree.c
+++ b/fs/btrfs/debug-tree.c
@@ -11,9 +11,11 @@
struct btrfs_root *root;
radix_tree_init();
root = open_ctree("dbfile", &super);
- printf("root tree\n");
+ printf("fs tree\n");
btrfs_print_tree(root, root->node);
printf("map tree\n");
btrfs_print_tree(root->extent_root, root->extent_root->node);
+ printf("root tree\n");
+ btrfs_print_tree(root->tree_root, root->tree_root->node);
return 0;
}
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index c34c0c6..3d4bf68 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -154,41 +154,96 @@
return ret;
}
+static int commit_extent_and_tree_roots(struct btrfs_root *tree_root,
+ struct btrfs_root *extent_root)
+{
+ int ret;
+ u64 old_extent_block;
+
+ while(1) {
+ old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
+ if (old_extent_block == extent_root->node->blocknr)
+ break;
+ btrfs_set_root_blocknr(&extent_root->root_item,
+ extent_root->node->blocknr);
+ ret = btrfs_update_root(tree_root,
+ &extent_root->root_key,
+ &extent_root->root_item);
+ BUG_ON(ret);
+ }
+ __commit_transaction(extent_root);
+ __commit_transaction(tree_root);
+ return 0;
+}
+
int btrfs_commit_transaction(struct btrfs_root *root,
struct btrfs_super_block *s)
{
int ret = 0;
+ struct btrfs_buffer *snap = root->commit_root;
+ struct btrfs_key snap_key;
ret = __commit_transaction(root);
- if (!ret && root != root->extent_root)
- ret = __commit_transaction(root->extent_root);
BUG_ON(ret);
- if (root->commit_root != root->node) {
- struct btrfs_buffer *snap = root->commit_root;
- root->commit_root = root->node;
- root->node->count++;
- ret = btrfs_drop_snapshot(root, snap);
- BUG_ON(ret);
- // btrfs_block_release(root, snap);
- }
+
+ if (root->commit_root == root->node)
+ return 0;
+
+ memcpy(&snap_key, &root->root_key, sizeof(snap_key));
+ root->root_key.offset++;
+
+ btrfs_set_root_blocknr(&root->root_item, root->node->blocknr);
+ ret = btrfs_insert_root(root->tree_root, &root->root_key,
+ &root->root_item);
+ BUG_ON(ret);
+
+ ret = commit_extent_and_tree_roots(root->tree_root, root->extent_root);
+ BUG_ON(ret);
+
write_ctree_super(root, s);
- btrfs_finish_extent_commit(root);
+ btrfs_finish_extent_commit(root->extent_root);
+ btrfs_finish_extent_commit(root->tree_root);
+
+ root->commit_root = root->node;
+ root->node->count++;
+ ret = btrfs_drop_snapshot(root, snap);
+ BUG_ON(ret);
+
+ ret = btrfs_del_root(root->tree_root, &snap_key);
+ BUG_ON(ret);
+
return ret;
}
-static int __setup_root(struct btrfs_root *root, struct btrfs_root *extent_root,
- struct btrfs_root_info *info, int fp)
+static int __setup_root(struct btrfs_root *root, u64 objectid, int fp)
{
INIT_LIST_HEAD(&root->trans);
INIT_LIST_HEAD(&root->cache);
root->cache_size = 0;
root->fp = fp;
root->node = NULL;
- root->extent_root = extent_root;
root->commit_root = NULL;
- root->node = read_tree_block(root, info->tree_root);
memset(&root->current_insert, 0, sizeof(root->current_insert));
memset(&root->last_insert, 0, sizeof(root->last_insert));
+ memset(&root->root_key, 0, sizeof(root->root_key));
+ memset(&root->root_item, 0, sizeof(root->root_item));
+ return 0;
+}
+
+static int find_and_setup_root(struct btrfs_root *tree_root, u64 objectid,
+ struct btrfs_root *root, int fp)
+{
+ int ret;
+
+ __setup_root(root, objectid, fp);
+ ret = btrfs_find_last_root(tree_root, objectid,
+ &root->root_item, &root->root_key);
+ BUG_ON(ret);
+
+ root->node = read_tree_block(root,
+ btrfs_root_blocknr(&root->root_item));
+ root->ref_cows = 0;
+ BUG_ON(!root->node);
return 0;
}
@@ -196,9 +251,19 @@
{
struct btrfs_root *root = malloc(sizeof(struct btrfs_root));
struct btrfs_root *extent_root = malloc(sizeof(struct btrfs_root));
+ struct btrfs_root *tree_root = malloc(sizeof(struct btrfs_root));
int fp;
int ret;
+ root->extent_root = extent_root;
+ root->tree_root = tree_root;
+
+ extent_root->extent_root = extent_root;
+ extent_root->tree_root = tree_root;
+
+ tree_root->extent_root = extent_root;
+ tree_root->tree_root = tree_root;
+
fp = open(filename, O_CREAT | O_RDWR, 0600);
if (fp < 0) {
free(root);
@@ -208,11 +273,14 @@
INIT_RADIX_TREE(&root->pinned_radix, GFP_KERNEL);
INIT_RADIX_TREE(&extent_root->pinned_radix, GFP_KERNEL);
INIT_RADIX_TREE(&extent_root->cache_radix, GFP_KERNEL);
+ INIT_RADIX_TREE(&tree_root->pinned_radix, GFP_KERNEL);
+ INIT_RADIX_TREE(&tree_root->cache_radix, GFP_KERNEL);
+
ret = pread(fp, super, sizeof(struct btrfs_super_block),
BTRFS_SUPER_INFO_OFFSET(BTRFS_BLOCKSIZE));
- if (ret == 0 || super->root_info.tree_root == 0) {
+ if (ret == 0 || btrfs_super_root(super) == 0) {
printf("making new FS!\n");
- ret = mkfs(fp);
+ ret = mkfs(fp, 0, BTRFS_BLOCKSIZE);
if (ret)
return NULL;
ret = pread(fp, super, sizeof(struct btrfs_super_block),
@@ -221,24 +289,29 @@
return NULL;
}
BUG_ON(ret < 0);
- __setup_root(root, extent_root, &super->root_info, fp);
- __setup_root(extent_root, extent_root, &super->extent_info, fp);
+
+ __setup_root(tree_root, BTRFS_ROOT_TREE_OBJECTID, fp);
+ tree_root->node = read_tree_block(tree_root, btrfs_super_root(super));
+ BUG_ON(!tree_root->node);
+
+ ret = find_and_setup_root(tree_root, BTRFS_EXTENT_TREE_OBJECTID,
+ extent_root, fp);
+ BUG_ON(ret);
+
+ ret = find_and_setup_root(tree_root, BTRFS_FS_TREE_OBJECTID,
+ root, fp);
+ BUG_ON(ret);
+
root->commit_root = root->node;
root->node->count++;
+ root->ref_cows = 1;
return root;
}
-static int __update_root(struct btrfs_root *root, struct btrfs_root_info *info)
-{
- info->tree_root = root->node->blocknr;
- return 0;
-}
-
int write_ctree_super(struct btrfs_root *root, struct btrfs_super_block *s)
{
int ret;
- __update_root(root, &s->root_info);
- __update_root(root->extent_root, &s->extent_info);
+ btrfs_set_super_root(s, root->tree_root->node->blocknr);
ret = pwrite(root->fp, s, sizeof(*s),
BTRFS_SUPER_INFO_OFFSET(BTRFS_BLOCKSIZE));
if (ret != sizeof(*s)) {
@@ -260,19 +333,25 @@
}
int close_ctree(struct btrfs_root *root, struct btrfs_super_block *s)
{
+ int ret;
btrfs_commit_transaction(root, s);
- __commit_transaction(root->extent_root);
+ ret = commit_extent_and_tree_roots(root->tree_root, root->extent_root);
+ BUG_ON(ret);
write_ctree_super(root, s);
drop_cache(root->extent_root);
+ drop_cache(root->tree_root);
drop_cache(root);
BUG_ON(!list_empty(&root->trans));
BUG_ON(!list_empty(&root->extent_root->trans));
+ BUG_ON(!list_empty(&root->tree_root->trans));
close(root->fp);
if (root->node)
btrfs_block_release(root, root->node);
if (root->extent_root->node)
btrfs_block_release(root->extent_root, root->extent_root->node);
+ if (root->tree_root->node)
+ btrfs_block_release(root->tree_root, root->tree_root->node);
btrfs_block_release(root, root->commit_root);
free(root);
printf("on close %d blocks are allocated\n", allocated_blocks);
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index b391335..c22a61f 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -24,7 +24,8 @@
int close_ctree(struct btrfs_root *root, struct btrfs_super_block *s);
void btrfs_block_release(struct btrfs_root *root, struct btrfs_buffer *buf);
int write_ctree_super(struct btrfs_root *root, struct btrfs_super_block *s);
-int mkfs(int fd);
+int mkfs(int fd, u64 num_blocks, u16 blocksize);
+
#define BTRFS_SUPER_INFO_OFFSET(bs) (16 * (bs))
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index a696953..21f39b40 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -82,7 +82,7 @@
u64 blocknr;
int i;
- if (root == root->extent_root)
+ if (!root->ref_cows)
return 0;
if (btrfs_is_leaf(&buf->node))
return 0;
@@ -96,23 +96,22 @@
int btrfs_finish_extent_commit(struct btrfs_root *root)
{
- struct btrfs_root *extent_root = root->extent_root;
unsigned long gang[8];
int ret;
int i;
while(1) {
- ret = radix_tree_gang_lookup(&extent_root->pinned_radix,
+ ret = radix_tree_gang_lookup(&root->pinned_radix,
(void **)gang, 0,
ARRAY_SIZE(gang));
if (!ret)
break;
for (i = 0; i < ret; i++) {
- radix_tree_delete(&extent_root->pinned_radix, gang[i]);
+ radix_tree_delete(&root->pinned_radix, gang[i]);
}
}
- extent_root->last_insert.objectid = 0;
- extent_root->last_insert.offset = 0;
+ root->last_insert.objectid = 0;
+ root->last_insert.offset = 0;
return 0;
}
@@ -173,7 +172,7 @@
refs = btrfs_extent_refs(ei) - 1;
btrfs_set_extent_refs(ei, refs);
if (refs == 0) {
- if (root == extent_root) {
+ if (!root->ref_cows) {
int err;
radix_tree_preload(GFP_KERNEL);
err = radix_tree_insert(&extent_root->pinned_radix,
@@ -513,7 +512,7 @@
*/
int btrfs_drop_snapshot(struct btrfs_root *root, struct btrfs_buffer *snap)
{
- int ret = 0;;
+ int ret = 0;
int wret;
int level;
struct btrfs_path path;
diff --git a/fs/btrfs/mkfs.c b/fs/btrfs/mkfs.c
index fc19233..dd14ed4 100644
--- a/fs/btrfs/mkfs.c
+++ b/fs/btrfs/mkfs.c
@@ -10,6 +10,120 @@
#include "ctree.h"
#include "disk-io.h"
+int mkfs(int fd, u64 num_blocks, u16 blocksize)
+{
+ struct btrfs_super_block super;
+ struct btrfs_leaf empty_leaf;
+ struct btrfs_root_item root_item;
+ struct btrfs_item item;
+ struct btrfs_extent_item extent_item;
+ char *block;
+ int ret;
+ u16 itemoff;
+
+ btrfs_set_super_blocknr(&super, 16);
+ btrfs_set_super_root(&super, 17);
+ strcpy((char *)(&super.magic), BTRFS_MAGIC);
+ btrfs_set_super_blocksize(&super, blocksize);
+ btrfs_set_super_total_blocks(&super, num_blocks);
+ btrfs_set_super_blocks_used(&super, 0);
+
+ block = malloc(blocksize);
+ memset(block, 0, blocksize);
+ BUG_ON(sizeof(super) > blocksize);
+ memcpy(block, &super, sizeof(super));
+ ret = pwrite(fd, block, blocksize, BTRFS_SUPER_INFO_OFFSET(blocksize));
+ BUG_ON(ret != blocksize);
+
+ /* create the tree of root objects */
+ memset(&empty_leaf, 0, sizeof(empty_leaf));
+ btrfs_set_header_parentid(&empty_leaf.header, BTRFS_ROOT_TREE_OBJECTID);
+ btrfs_set_header_blocknr(&empty_leaf.header, 17);
+ btrfs_set_header_nritems(&empty_leaf.header, 2);
+
+ /* create the items for the root tree */
+ btrfs_set_root_blocknr(&root_item, 18);
+ btrfs_set_root_refs(&root_item, 1);
+ itemoff = LEAF_DATA_SIZE - sizeof(root_item);
+ btrfs_set_item_offset(&item, itemoff);
+ btrfs_set_item_size(&item, sizeof(root_item));
+ btrfs_set_key_objectid(&item.key, BTRFS_EXTENT_TREE_OBJECTID);
+ btrfs_set_key_offset(&item.key, 0);
+ btrfs_set_key_flags(&item.key, 0);
+ memcpy(empty_leaf.items, &item, sizeof(item));
+ memcpy(empty_leaf.data + itemoff, &root_item, sizeof(root_item));
+
+ btrfs_set_root_blocknr(&root_item, 19);
+ itemoff = itemoff - sizeof(root_item);
+ btrfs_set_item_offset(&item, itemoff);
+ btrfs_set_key_objectid(&item.key, BTRFS_FS_TREE_OBJECTID);
+ memcpy(empty_leaf.items + 1, &item, sizeof(item));
+ memcpy(empty_leaf.data + itemoff, &root_item, sizeof(root_item));
+ ret = pwrite(fd, &empty_leaf, blocksize, 17 * blocksize);
+
+ /* create the items for the extent tree */
+ btrfs_set_header_parentid(&empty_leaf.header,
+ BTRFS_EXTENT_TREE_OBJECTID);
+ btrfs_set_header_blocknr(&empty_leaf.header, 18);
+ btrfs_set_header_nritems(&empty_leaf.header, 4);
+
+ /* item1, reserve blocks 0-16 */
+ btrfs_set_key_objectid(&item.key, 0);
+ btrfs_set_key_offset(&item.key, 17);
+ btrfs_set_key_flags(&item.key, 0);
+ itemoff = LEAF_DATA_SIZE - sizeof(struct btrfs_extent_item);
+ btrfs_set_item_offset(&item, itemoff);
+ btrfs_set_item_size(&item, sizeof(struct btrfs_extent_item));
+ btrfs_set_extent_refs(&extent_item, 1);
+ btrfs_set_extent_owner(&extent_item, 0);
+ memcpy(empty_leaf.items, &item, sizeof(item));
+ memcpy(empty_leaf.data + btrfs_item_offset(&item), &extent_item,
+ btrfs_item_size(&item));
+
+ /* item2, give block 17 to the root */
+ btrfs_set_key_objectid(&item.key, 17);
+ btrfs_set_key_offset(&item.key, 1);
+ itemoff = itemoff - sizeof(struct btrfs_extent_item);
+ btrfs_set_item_offset(&item, itemoff);
+ btrfs_set_extent_owner(&extent_item, BTRFS_ROOT_TREE_OBJECTID);
+ memcpy(empty_leaf.items + 1, &item, sizeof(item));
+ memcpy(empty_leaf.data + btrfs_item_offset(&item), &extent_item,
+ btrfs_item_size(&item));
+
+ /* item3, give block 18 to the extent root */
+ btrfs_set_key_objectid(&item.key, 18);
+ btrfs_set_key_offset(&item.key, 1);
+ itemoff = itemoff - sizeof(struct btrfs_extent_item);
+ btrfs_set_item_offset(&item, itemoff);
+ btrfs_set_extent_owner(&extent_item, BTRFS_EXTENT_TREE_OBJECTID);
+ memcpy(empty_leaf.items + 2, &item, sizeof(item));
+ memcpy(empty_leaf.data + btrfs_item_offset(&item), &extent_item,
+ btrfs_item_size(&item));
+
+ /* item4, give block 19 to the FS root */
+ btrfs_set_key_objectid(&item.key, 19);
+ btrfs_set_key_offset(&item.key, 1);
+ itemoff = itemoff - sizeof(struct btrfs_extent_item);
+ btrfs_set_item_offset(&item, itemoff);
+ btrfs_set_extent_owner(&extent_item, BTRFS_FS_TREE_OBJECTID);
+ memcpy(empty_leaf.items + 3, &item, sizeof(item));
+ memcpy(empty_leaf.data + btrfs_item_offset(&item), &extent_item,
+ btrfs_item_size(&item));
+ ret = pwrite(fd, &empty_leaf, blocksize, 18 * blocksize);
+ if (ret != sizeof(empty_leaf))
+ return -1;
+
+ /* finally create the FS root */
+ btrfs_set_header_parentid(&empty_leaf.header, BTRFS_FS_TREE_OBJECTID);
+ btrfs_set_header_blocknr(&empty_leaf.header, 19);
+ btrfs_set_header_nritems(&empty_leaf.header, 0);
+ ret = pwrite(fd, &empty_leaf, blocksize, 19 * blocksize);
+ if (ret != sizeof(empty_leaf))
+ return -1;
+ return 0;
+}
+
+#if 0
int mkfs(int fd)
{
struct btrfs_root_info info[2];
@@ -20,13 +134,14 @@
/* setup the super block area */
memset(info, 0, sizeof(info));
- info[0].blocknr = 16;
- info[0].objectid = 1;
- info[0].tree_root = 17;
+ btrfs_set_root_blocknr(info, 16);
+ btrfs_set_root_objectid(info, 1);
+ btrfs_set_root_tree_root(info, 17);
- info[1].blocknr = 16;
- info[1].objectid = 2;
- info[1].tree_root = 18;
+ btrfs_set_root_blocknr(info + 1, 16);
+ btrfs_set_root_objectid(info + 1, 2);
+ btrfs_set_root_tree_root(info + 1, 18);
+
ret = pwrite(fd, info, sizeof(info),
BTRFS_SUPER_INFO_OFFSET(BTRFS_BLOCKSIZE));
if (ret != sizeof(info))
@@ -81,3 +196,4 @@
return -1;
return 0;
}
+#endif
diff --git a/fs/btrfs/print-tree.c b/fs/btrfs/print-tree.c
index c95c856..64829b6 100644
--- a/fs/btrfs/print-tree.c
+++ b/fs/btrfs/print-tree.c
@@ -11,6 +11,7 @@
u32 nr = btrfs_header_nritems(&l->header);
struct btrfs_item *item;
struct btrfs_extent_item *ei;
+ struct btrfs_root_item *ri;
printf("leaf %Lu total ptrs %d free space %d\n",
btrfs_header_blocknr(&l->header), nr, btrfs_leaf_free_space(l));
fflush(stdout);
@@ -23,13 +24,15 @@
btrfs_key_offset(&item->key),
btrfs_item_offset(item),
btrfs_item_size(item));
- fflush(stdout);
printf("\t\titem data %.*s\n", btrfs_item_size(item),
l->data + btrfs_item_offset(item));
ei = (struct btrfs_extent_item *)(l->data +
btrfs_item_offset(item));
- printf("\t\textent data refs %u owner %Lu\n", ei->refs,
- ei->owner);
+ printf("\t\textent data refs %u owner %Lu\n",
+ btrfs_extent_refs(ei), btrfs_extent_owner(ei));
+ ri = (struct btrfs_root_item *)ei;
+ printf("\t\troot data blocknr %Lu refs %u\n",
+ btrfs_root_blocknr(ri), btrfs_root_refs(ri));
fflush(stdout);
}
}
@@ -71,6 +74,5 @@
btrfs_print_tree(root, next_buf);
btrfs_block_release(root, next_buf);
}
-
}
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
new file mode 100644
index 0000000..0ab90cf
--- /dev/null
+++ b/fs/btrfs/root-tree.c
@@ -0,0 +1,88 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "kerncompat.h"
+#include "radix-tree.h"
+#include "ctree.h"
+#include "disk-io.h"
+#include "print-tree.h"
+
+int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
+ struct btrfs_root_item *item, struct btrfs_key *key)
+{
+ struct btrfs_path path;
+ struct btrfs_key search_key;
+ struct btrfs_leaf *l;
+ int ret;
+ int slot;
+
+ search_key.objectid = objectid;
+ search_key.flags = (u32)-1;
+ search_key.offset = (u32)-1;
+
+ btrfs_init_path(&path);
+ ret = btrfs_search_slot(root, &search_key, &path, 0, 0);
+ if (ret < 0)
+ goto out;
+ BUG_ON(ret == 0);
+ l = &path.nodes[0]->leaf;
+ BUG_ON(path.slots[0] == 0);
+ slot = path.slots[0] - 1;
+ if (btrfs_key_objectid(&l->items[slot].key) != objectid) {
+ ret = 1;
+ goto out;
+ }
+ memcpy(item, l->data + btrfs_item_offset(l->items + slot),
+ sizeof(*item));
+ btrfs_disk_key_to_cpu(key, &l->items[slot].key);
+ btrfs_release_path(root, &path);
+ ret = 0;
+out:
+ return ret;
+}
+
+int btrfs_update_root(struct btrfs_root *root, struct btrfs_key *key,
+ struct btrfs_root_item *item)
+{
+ struct btrfs_path path;
+ struct btrfs_leaf *l;
+ int ret;
+ int slot;
+
+ btrfs_init_path(&path);
+ ret = btrfs_search_slot(root, key, &path, 0, 1);
+ if (ret < 0)
+ goto out;
+ BUG_ON(ret != 0);
+ l = &path.nodes[0]->leaf;
+ slot = path.slots[0];
+ memcpy(l->data + btrfs_item_offset(l->items + slot), item,
+ sizeof(*item));
+out:
+ btrfs_release_path(root, &path);
+ return ret;
+}
+
+int btrfs_insert_root(struct btrfs_root *root, struct btrfs_key *key,
+ struct btrfs_root_item *item)
+{
+ int ret;
+ ret = btrfs_insert_item(root, key, item, sizeof(*item));
+ BUG_ON(ret);
+ return ret;
+}
+
+int btrfs_del_root(struct btrfs_root *root, struct btrfs_key *key)
+{
+ struct btrfs_path path;
+ int ret;
+
+ btrfs_init_path(&path);
+ ret = btrfs_search_slot(root, key, &path, -1, 1);
+ if (ret < 0)
+ goto out;
+ BUG_ON(ret != 0);
+ ret = btrfs_del_item(root, &path);
+out:
+ btrfs_release_path(root, &path);
+ return ret;
+}