Change the super to point to a tree of trees to enable persistent snapshots
This commit is contained in:
Chris Mason
David Woodhouse
parent
6a332a71ba
commit
d9c9960f8d
10 changed files with 445 additions and 65 deletions
3
Makefile
3
Makefile
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@ -2,7 +2,8 @@
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CC=gcc
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CFLAGS = -g -Wall
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headers = radix-tree.h ctree.h disk-io.h kerncompat.h print-tree.h list.h
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objects = ctree.o disk-io.o radix-tree.o mkfs.o extent-tree.o print-tree.o
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objects = ctree.o disk-io.o radix-tree.o mkfs.o extent-tree.o print-tree.o \
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root-tree.o
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# if you don't have sparse installed, use ls instead
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CHECKFLAGS=-D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ -Wbitwise \
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1
TODO
1
TODO
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@ -5,6 +5,7 @@
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* make a real mkfs and superblock
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* Do checksumming
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* Define FS objects in terms of different item types
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* add inode tree
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* Add block mapping tree (simple dm layer)
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* Add simple tree locking (semaphore per tree)
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* Make allocator smarter
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123
ctree.h
123
ctree.h
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@ -4,8 +4,13 @@
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#include "list.h"
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#include "kerncompat.h"
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#define BTRFS_MAGIC "_BtRfS_M"
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#define BTRFS_BLOCKSIZE 1024
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#define BTRFS_ROOT_TREE_OBJECTID 1
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#define BTRFS_EXTENT_TREE_OBJECTID 2
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#define BTRFS_FS_TREE_OBJECTID 3
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/*
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* the key defines the order in the tree, and so it also defines (optimal)
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* block layout. objectid corresonds to the inode number. The flags
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@ -36,7 +41,7 @@ struct btrfs_key {
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* every tree block (leaf or node) starts with this header.
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*/
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struct btrfs_header {
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__le64 fsid[2]; /* FS specific uuid */
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u8 fsid[16]; /* FS specific uuid */
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__le64 blocknr; /* which block this node is supposed to live in */
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__le64 parentid; /* objectid of the tree root */
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__le32 csum;
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@ -52,6 +57,14 @@ struct btrfs_header {
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struct btrfs_buffer;
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struct btrfs_root_item {
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__le64 blocknr;
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__le32 flags;
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__le64 block_limit;
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__le64 blocks_used;
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__le32 refs;
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};
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/*
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* in ram representation of the tree. extent_root is used for all allocations
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* and for the extent tree extent_root root. current_insert is used
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@ -61,6 +74,7 @@ struct btrfs_root {
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struct btrfs_buffer *node;
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struct btrfs_buffer *commit_root;
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struct btrfs_root *extent_root;
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struct btrfs_root *tree_root;
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struct btrfs_key current_insert;
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struct btrfs_key last_insert;
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int fp;
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@ -69,28 +83,25 @@ struct btrfs_root {
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struct list_head trans;
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struct list_head cache;
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int cache_size;
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int ref_cows;
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struct btrfs_root_item root_item;
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struct btrfs_key root_key;
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};
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/*
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* describes a tree on disk
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*/
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struct btrfs_root_info {
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u64 fsid[2]; /* FS specific uuid */
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u64 blocknr; /* blocknr of this block */
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u64 objectid; /* inode number of this root */
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u64 tree_root; /* the tree root block */
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u32 csum;
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u32 ham;
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u64 snapuuid[2]; /* root specific uuid */
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} __attribute__ ((__packed__));
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/*
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* the super block basically lists the main trees of the FS
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* it currently lacks any block count etc etc
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*/
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struct btrfs_super_block {
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struct btrfs_root_info root_info;
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struct btrfs_root_info extent_info;
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u8 fsid[16]; /* FS specific uuid */
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__le64 blocknr; /* this block number */
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__le32 csum;
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__le64 magic;
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__le16 blocksize;
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__le64 generation;
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__le64 root;
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__le64 total_blocks;
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__le64 blocks_used;
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} __attribute__ ((__packed__));
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/*
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@ -317,6 +328,79 @@ static inline int btrfs_is_leaf(struct btrfs_node *n)
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return (btrfs_header_level(&n->header) == 0);
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}
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static inline u64 btrfs_root_blocknr(struct btrfs_root_item *item)
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{
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return le64_to_cpu(item->blocknr);
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}
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static inline void btrfs_set_root_blocknr(struct btrfs_root_item *item, u64 val)
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{
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item->blocknr = cpu_to_le64(val);
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}
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static inline u32 btrfs_root_refs(struct btrfs_root_item *item)
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{
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return le32_to_cpu(item->refs);
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}
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static inline void btrfs_set_root_refs(struct btrfs_root_item *item, u32 val)
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{
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item->refs = cpu_to_le32(val);
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}
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static inline u64 btrfs_super_blocknr(struct btrfs_super_block *s)
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{
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return le64_to_cpu(s->blocknr);
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}
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static inline void btrfs_set_super_blocknr(struct btrfs_super_block *s, u64 val)
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{
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s->blocknr = cpu_to_le64(val);
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}
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static inline u64 btrfs_super_root(struct btrfs_super_block *s)
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{
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return le64_to_cpu(s->root);
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}
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static inline void btrfs_set_super_root(struct btrfs_super_block *s, u64 val)
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{
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s->root = cpu_to_le64(val);
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}
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static inline u64 btrfs_super_total_blocks(struct btrfs_super_block *s)
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{
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return le64_to_cpu(s->total_blocks);
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}
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static inline void btrfs_set_super_total_blocks(struct btrfs_super_block *s,
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u64 val)
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{
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s->total_blocks = cpu_to_le64(val);
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}
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static inline u64 btrfs_super_blocks_used(struct btrfs_super_block *s)
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{
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return le64_to_cpu(s->blocks_used);
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}
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static inline void btrfs_set_super_blocks_used(struct btrfs_super_block *s,
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u64 val)
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{
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s->blocks_used = cpu_to_le64(val);
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}
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static inline u16 btrfs_super_blocksize(struct btrfs_super_block *s)
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{
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return le16_to_cpu(s->blocksize);
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}
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static inline void btrfs_set_super_blocksize(struct btrfs_super_block *s,
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u16 val)
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{
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s->blocksize = cpu_to_le16(val);
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}
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struct btrfs_buffer *btrfs_alloc_free_block(struct btrfs_root *root);
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int btrfs_inc_ref(struct btrfs_root *root, struct btrfs_buffer *buf);
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int btrfs_free_extent(struct btrfs_root *root, u64 blocknr, u64 num_blocks);
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@ -331,4 +415,11 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path);
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int btrfs_leaf_free_space(struct btrfs_leaf *leaf);
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int btrfs_drop_snapshot(struct btrfs_root *root, struct btrfs_buffer *snap);
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int btrfs_finish_extent_commit(struct btrfs_root *root);
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int btrfs_del_root(struct btrfs_root *root, struct btrfs_key *key);
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int btrfs_insert_root(struct btrfs_root *root, struct btrfs_key *key,
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struct btrfs_root_item *item);
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int btrfs_update_root(struct btrfs_root *root, struct btrfs_key *key,
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struct btrfs_root_item *item);
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int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
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struct btrfs_root_item *item, struct btrfs_key *key);
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#endif
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@ -11,9 +11,11 @@ int main(int ac, char **av) {
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struct btrfs_root *root;
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radix_tree_init();
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root = open_ctree("dbfile", &super);
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printf("root tree\n");
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printf("fs tree\n");
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btrfs_print_tree(root, root->node);
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printf("map tree\n");
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btrfs_print_tree(root->extent_root, root->extent_root->node);
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printf("root tree\n");
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btrfs_print_tree(root->tree_root, root->tree_root->node);
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return 0;
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}
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135
disk-io.c
135
disk-io.c
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@ -154,41 +154,96 @@ static int __commit_transaction(struct btrfs_root *root)
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return ret;
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}
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static int commit_extent_and_tree_roots(struct btrfs_root *tree_root,
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struct btrfs_root *extent_root)
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{
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int ret;
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u64 old_extent_block;
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while(1) {
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old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
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if (old_extent_block == extent_root->node->blocknr)
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break;
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btrfs_set_root_blocknr(&extent_root->root_item,
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extent_root->node->blocknr);
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ret = btrfs_update_root(tree_root,
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&extent_root->root_key,
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&extent_root->root_item);
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BUG_ON(ret);
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}
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__commit_transaction(extent_root);
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__commit_transaction(tree_root);
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return 0;
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}
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int btrfs_commit_transaction(struct btrfs_root *root,
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struct btrfs_super_block *s)
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{
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int ret = 0;
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struct btrfs_buffer *snap = root->commit_root;
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struct btrfs_key snap_key;
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ret = __commit_transaction(root);
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if (!ret && root != root->extent_root)
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ret = __commit_transaction(root->extent_root);
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BUG_ON(ret);
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if (root->commit_root != root->node) {
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struct btrfs_buffer *snap = root->commit_root;
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root->commit_root = root->node;
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root->node->count++;
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ret = btrfs_drop_snapshot(root, snap);
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BUG_ON(ret);
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// btrfs_block_release(root, snap);
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}
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if (root->commit_root == root->node)
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return 0;
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memcpy(&snap_key, &root->root_key, sizeof(snap_key));
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root->root_key.offset++;
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btrfs_set_root_blocknr(&root->root_item, root->node->blocknr);
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ret = btrfs_insert_root(root->tree_root, &root->root_key,
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&root->root_item);
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BUG_ON(ret);
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ret = commit_extent_and_tree_roots(root->tree_root, root->extent_root);
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BUG_ON(ret);
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write_ctree_super(root, s);
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btrfs_finish_extent_commit(root);
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btrfs_finish_extent_commit(root->extent_root);
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btrfs_finish_extent_commit(root->tree_root);
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root->commit_root = root->node;
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root->node->count++;
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ret = btrfs_drop_snapshot(root, snap);
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BUG_ON(ret);
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ret = btrfs_del_root(root->tree_root, &snap_key);
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BUG_ON(ret);
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return ret;
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}
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static int __setup_root(struct btrfs_root *root, struct btrfs_root *extent_root,
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struct btrfs_root_info *info, int fp)
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static int __setup_root(struct btrfs_root *root, u64 objectid, int fp)
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{
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INIT_LIST_HEAD(&root->trans);
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INIT_LIST_HEAD(&root->cache);
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root->cache_size = 0;
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root->fp = fp;
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root->node = NULL;
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root->extent_root = extent_root;
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root->commit_root = NULL;
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root->node = read_tree_block(root, info->tree_root);
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memset(&root->current_insert, 0, sizeof(root->current_insert));
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memset(&root->last_insert, 0, sizeof(root->last_insert));
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memset(&root->root_key, 0, sizeof(root->root_key));
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memset(&root->root_item, 0, sizeof(root->root_item));
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return 0;
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}
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static int find_and_setup_root(struct btrfs_root *tree_root, u64 objectid,
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struct btrfs_root *root, int fp)
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{
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int ret;
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__setup_root(root, objectid, fp);
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ret = btrfs_find_last_root(tree_root, objectid,
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&root->root_item, &root->root_key);
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BUG_ON(ret);
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root->node = read_tree_block(root,
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btrfs_root_blocknr(&root->root_item));
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root->ref_cows = 0;
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BUG_ON(!root->node);
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return 0;
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}
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@ -196,9 +251,19 @@ struct btrfs_root *open_ctree(char *filename, struct btrfs_super_block *super)
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{
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struct btrfs_root *root = malloc(sizeof(struct btrfs_root));
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struct btrfs_root *extent_root = malloc(sizeof(struct btrfs_root));
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struct btrfs_root *tree_root = malloc(sizeof(struct btrfs_root));
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int fp;
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int ret;
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root->extent_root = extent_root;
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root->tree_root = tree_root;
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extent_root->extent_root = extent_root;
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extent_root->tree_root = tree_root;
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tree_root->extent_root = extent_root;
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tree_root->tree_root = tree_root;
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fp = open(filename, O_CREAT | O_RDWR, 0600);
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if (fp < 0) {
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free(root);
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@ -208,11 +273,14 @@ struct btrfs_root *open_ctree(char *filename, struct btrfs_super_block *super)
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INIT_RADIX_TREE(&root->pinned_radix, GFP_KERNEL);
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INIT_RADIX_TREE(&extent_root->pinned_radix, GFP_KERNEL);
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INIT_RADIX_TREE(&extent_root->cache_radix, GFP_KERNEL);
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INIT_RADIX_TREE(&tree_root->pinned_radix, GFP_KERNEL);
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INIT_RADIX_TREE(&tree_root->cache_radix, GFP_KERNEL);
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ret = pread(fp, super, sizeof(struct btrfs_super_block),
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BTRFS_SUPER_INFO_OFFSET(BTRFS_BLOCKSIZE));
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if (ret == 0 || super->root_info.tree_root == 0) {
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if (ret == 0 || btrfs_super_root(super) == 0) {
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printf("making new FS!\n");
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ret = mkfs(fp);
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ret = mkfs(fp, 0, BTRFS_BLOCKSIZE);
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if (ret)
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return NULL;
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ret = pread(fp, super, sizeof(struct btrfs_super_block),
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@ -221,24 +289,29 @@ struct btrfs_root *open_ctree(char *filename, struct btrfs_super_block *super)
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return NULL;
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}
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BUG_ON(ret < 0);
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__setup_root(root, extent_root, &super->root_info, fp);
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__setup_root(extent_root, extent_root, &super->extent_info, fp);
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__setup_root(tree_root, BTRFS_ROOT_TREE_OBJECTID, fp);
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tree_root->node = read_tree_block(tree_root, btrfs_super_root(super));
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BUG_ON(!tree_root->node);
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ret = find_and_setup_root(tree_root, BTRFS_EXTENT_TREE_OBJECTID,
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extent_root, fp);
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BUG_ON(ret);
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ret = find_and_setup_root(tree_root, BTRFS_FS_TREE_OBJECTID,
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root, fp);
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BUG_ON(ret);
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root->commit_root = root->node;
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root->node->count++;
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root->ref_cows = 1;
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return root;
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}
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static int __update_root(struct btrfs_root *root, struct btrfs_root_info *info)
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{
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info->tree_root = root->node->blocknr;
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return 0;
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}
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int write_ctree_super(struct btrfs_root *root, struct btrfs_super_block *s)
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{
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int ret;
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__update_root(root, &s->root_info);
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__update_root(root->extent_root, &s->extent_info);
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btrfs_set_super_root(s, root->tree_root->node->blocknr);
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ret = pwrite(root->fp, s, sizeof(*s),
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BTRFS_SUPER_INFO_OFFSET(BTRFS_BLOCKSIZE));
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if (ret != sizeof(*s)) {
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@ -260,19 +333,25 @@ static int drop_cache(struct btrfs_root *root)
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}
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int close_ctree(struct btrfs_root *root, struct btrfs_super_block *s)
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{
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int ret;
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btrfs_commit_transaction(root, s);
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__commit_transaction(root->extent_root);
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ret = commit_extent_and_tree_roots(root->tree_root, root->extent_root);
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BUG_ON(ret);
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write_ctree_super(root, s);
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drop_cache(root->extent_root);
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drop_cache(root->tree_root);
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drop_cache(root);
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BUG_ON(!list_empty(&root->trans));
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BUG_ON(!list_empty(&root->extent_root->trans));
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BUG_ON(!list_empty(&root->tree_root->trans));
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close(root->fp);
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if (root->node)
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btrfs_block_release(root, root->node);
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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);
|
||||
|
|
|
|||
|
|
@ -24,7 +24,8 @@ struct btrfs_root *open_ctree(char *filename, struct btrfs_super_block *s);
|
|||
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))
|
||||
|
||||
|
|
|
|||
|
|
@ -82,7 +82,7 @@ int btrfs_inc_ref(struct btrfs_root *root, struct btrfs_buffer *buf)
|
|||
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_inc_ref(struct btrfs_root *root, struct btrfs_buffer *buf)
|
|||
|
||||
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 @@ static int __free_extent(struct btrfs_root *root, u64 blocknr, u64 num_blocks)
|
|||
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 @@ static int walk_up_tree(struct btrfs_root *root, struct btrfs_path *path,
|
|||
*/
|
||||
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;
|
||||
|
|
|
|||
128
mkfs.c
128
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 @@ int mkfs(int fd)
|
|||
|
||||
/* 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);
|
||||
|
||||
btrfs_set_root_blocknr(info + 1, 16);
|
||||
btrfs_set_root_objectid(info + 1, 2);
|
||||
btrfs_set_root_tree_root(info + 1, 18);
|
||||
|
||||
info[1].blocknr = 16;
|
||||
info[1].objectid = 2;
|
||||
info[1].tree_root = 18;
|
||||
ret = pwrite(fd, info, sizeof(info),
|
||||
BTRFS_SUPER_INFO_OFFSET(BTRFS_BLOCKSIZE));
|
||||
if (ret != sizeof(info))
|
||||
|
|
@ -81,3 +196,4 @@ int mkfs(int fd)
|
|||
return -1;
|
||||
return 0;
|
||||
}
|
||||
#endif
|
||||
|
|
|
|||
10
print-tree.c
10
print-tree.c
|
|
@ -11,6 +11,7 @@ void btrfs_print_leaf(struct btrfs_leaf *l)
|
|||
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 @@ void btrfs_print_leaf(struct btrfs_leaf *l)
|
|||
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 @@ void btrfs_print_tree(struct btrfs_root *root, struct btrfs_buffer *t)
|
|||
btrfs_print_tree(root, next_buf);
|
||||
btrfs_block_release(root, next_buf);
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
|
|
|
|||
88
root-tree.c
Normal file
88
root-tree.c
Normal file
|
|
@ -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;
|
||||
}
|
||||
Loading…
Reference in a new issue