334 lines
8.7 KiB
C
334 lines
8.7 KiB
C
#ifndef __BTRFS__
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#define __BTRFS__
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#include "list.h"
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#include "kerncompat.h"
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#define BTRFS_BLOCKSIZE 1024
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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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* tells us things about the object, and is a kind of stream selector.
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* so for a given inode, keys with flags of 1 might refer to the inode
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* data, flags of 2 may point to file data in the btree and flags == 3
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* may point to extents.
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*
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* offset is the starting byte offset for this key in the stream.
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*
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* btrfs_disk_key is in disk byte order. struct btrfs_key is always
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* in cpu native order. Otherwise they are identical and their sizes
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* should be the same (ie both packed)
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*/
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struct btrfs_disk_key {
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__le64 objectid;
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__le32 flags;
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__le64 offset;
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} __attribute__ ((__packed__));
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struct btrfs_key {
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u64 objectid;
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u32 flags;
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u64 offset;
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} __attribute__ ((__packed__));
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/*
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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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__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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__le32 ham;
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__le16 nritems;
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__le16 flags;
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/* generation flags to be added */
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} __attribute__ ((__packed__));
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#define BTRFS_MAX_LEVEL 8
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#define NODEPTRS_PER_BLOCK ((BTRFS_BLOCKSIZE - sizeof(struct btrfs_header)) / \
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(sizeof(struct btrfs_disk_key) + sizeof(u64)))
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struct btrfs_buffer;
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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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* only for the extent tree.
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*/
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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_key current_insert;
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struct btrfs_key last_insert;
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int fp;
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struct radix_tree_root cache_radix;
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struct radix_tree_root pinned_radix;
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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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};
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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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} __attribute__ ((__packed__));
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/*
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* A leaf is full of items. The exact type of item is defined by
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* the key flags parameter. offset and size tell us where to find
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* the item in the leaf (relative to the start of the data area)
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*/
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struct btrfs_item {
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struct btrfs_disk_key key;
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__le16 offset;
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__le16 size;
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} __attribute__ ((__packed__));
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/*
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* leaves have an item area and a data area:
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* [item0, item1....itemN] [free space] [dataN...data1, data0]
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*
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* The data is separate from the items to get the keys closer together
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* during searches.
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*/
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#define LEAF_DATA_SIZE (BTRFS_BLOCKSIZE - sizeof(struct btrfs_header))
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struct btrfs_leaf {
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struct btrfs_header header;
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union {
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struct btrfs_item items[LEAF_DATA_SIZE/
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sizeof(struct btrfs_item)];
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u8 data[BTRFS_BLOCKSIZE - sizeof(struct btrfs_header)];
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};
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} __attribute__ ((__packed__));
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/*
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* all non-leaf blocks are nodes, they hold only keys and pointers to
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* other blocks
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*/
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struct btrfs_node {
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struct btrfs_header header;
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struct btrfs_disk_key keys[NODEPTRS_PER_BLOCK];
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__le64 blockptrs[NODEPTRS_PER_BLOCK];
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} __attribute__ ((__packed__));
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/*
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* items in the extent btree are used to record the objectid of the
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* owner of the block and the number of references
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*/
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struct btrfs_extent_item {
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__le32 refs;
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__le64 owner;
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} __attribute__ ((__packed__));
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/*
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* btrfs_paths remember the path taken from the root down to the leaf.
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* level 0 is always the leaf, and nodes[1...BTRFS_MAX_LEVEL] will point
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* to any other levels that are present.
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*
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* The slots array records the index of the item or block pointer
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* used while walking the tree.
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*/
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struct btrfs_path {
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struct btrfs_buffer *nodes[BTRFS_MAX_LEVEL];
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int slots[BTRFS_MAX_LEVEL];
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};
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static inline u64 btrfs_extent_owner(struct btrfs_extent_item *ei)
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{
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return le64_to_cpu(ei->owner);
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}
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static inline void btrfs_set_extent_owner(struct btrfs_extent_item *ei, u64 val)
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{
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ei->owner = cpu_to_le64(val);
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}
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static inline u32 btrfs_extent_refs(struct btrfs_extent_item *ei)
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{
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return le32_to_cpu(ei->refs);
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}
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static inline void btrfs_set_extent_refs(struct btrfs_extent_item *ei, u32 val)
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{
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ei->refs = cpu_to_le32(val);
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}
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static inline u64 btrfs_node_blockptr(struct btrfs_node *n, int nr)
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{
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return le64_to_cpu(n->blockptrs[nr]);
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}
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static inline void btrfs_set_node_blockptr(struct btrfs_node *n, int nr,
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u64 val)
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{
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n->blockptrs[nr] = cpu_to_le64(val);
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}
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static inline u16 btrfs_item_offset(struct btrfs_item *item)
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{
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return le16_to_cpu(item->offset);
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}
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static inline void btrfs_set_item_offset(struct btrfs_item *item, u16 val)
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{
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item->offset = cpu_to_le16(val);
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}
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static inline u16 btrfs_item_end(struct btrfs_item *item)
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{
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return le16_to_cpu(item->offset) + le16_to_cpu(item->size);
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}
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static inline u16 btrfs_item_size(struct btrfs_item *item)
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{
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return le16_to_cpu(item->size);
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}
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static inline void btrfs_set_item_size(struct btrfs_item *item, u16 val)
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{
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item->size = cpu_to_le16(val);
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}
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static inline void btrfs_disk_key_to_cpu(struct btrfs_key *cpu,
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struct btrfs_disk_key *disk)
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{
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cpu->offset = le64_to_cpu(disk->offset);
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cpu->flags = le32_to_cpu(disk->flags);
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cpu->objectid = le64_to_cpu(disk->objectid);
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}
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static inline void btrfs_cpu_key_to_disk(struct btrfs_disk_key *disk,
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struct btrfs_key *cpu)
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{
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disk->offset = cpu_to_le64(cpu->offset);
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disk->flags = cpu_to_le32(cpu->flags);
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disk->objectid = cpu_to_le64(cpu->objectid);
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}
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static inline u64 btrfs_key_objectid(struct btrfs_disk_key *disk)
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{
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return le64_to_cpu(disk->objectid);
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}
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static inline void btrfs_set_key_objectid(struct btrfs_disk_key *disk,
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u64 val)
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{
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disk->objectid = cpu_to_le64(val);
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}
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static inline u64 btrfs_key_offset(struct btrfs_disk_key *disk)
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{
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return le64_to_cpu(disk->offset);
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}
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static inline void btrfs_set_key_offset(struct btrfs_disk_key *disk,
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u64 val)
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{
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disk->offset = cpu_to_le64(val);
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}
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static inline u32 btrfs_key_flags(struct btrfs_disk_key *disk)
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{
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return le32_to_cpu(disk->flags);
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}
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static inline void btrfs_set_key_flags(struct btrfs_disk_key *disk,
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u32 val)
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{
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disk->flags = cpu_to_le32(val);
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}
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static inline u64 btrfs_header_blocknr(struct btrfs_header *h)
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{
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return le64_to_cpu(h->blocknr);
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}
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static inline void btrfs_set_header_blocknr(struct btrfs_header *h, u64 blocknr)
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{
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h->blocknr = cpu_to_le64(blocknr);
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}
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static inline u64 btrfs_header_parentid(struct btrfs_header *h)
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{
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return le64_to_cpu(h->parentid);
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}
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static inline void btrfs_set_header_parentid(struct btrfs_header *h,
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u64 parentid)
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{
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h->parentid = cpu_to_le64(parentid);
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}
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static inline u16 btrfs_header_nritems(struct btrfs_header *h)
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{
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return le16_to_cpu(h->nritems);
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}
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static inline void btrfs_set_header_nritems(struct btrfs_header *h, u16 val)
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{
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h->nritems = cpu_to_le16(val);
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}
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static inline u16 btrfs_header_flags(struct btrfs_header *h)
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{
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return le16_to_cpu(h->flags);
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}
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static inline void btrfs_set_header_flags(struct btrfs_header *h, u16 val)
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{
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h->flags = cpu_to_le16(val);
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}
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static inline int btrfs_header_level(struct btrfs_header *h)
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{
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return btrfs_header_flags(h) & (BTRFS_MAX_LEVEL - 1);
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}
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static inline void btrfs_set_header_level(struct btrfs_header *h, int level)
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{
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u16 flags;
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BUG_ON(level > BTRFS_MAX_LEVEL);
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flags = btrfs_header_flags(h) & ~(BTRFS_MAX_LEVEL - 1);
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btrfs_set_header_flags(h, flags | level);
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}
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static inline int btrfs_is_leaf(struct btrfs_node *n)
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{
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return (btrfs_header_level(&n->header) == 0);
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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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int btrfs_search_slot(struct btrfs_root *root, struct btrfs_key *key,
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struct btrfs_path *p, int ins_len, int cow);
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void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p);
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void btrfs_init_path(struct btrfs_path *p);
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int btrfs_del_item(struct btrfs_root *root, struct btrfs_path *path);
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int btrfs_insert_item(struct btrfs_root *root, struct btrfs_key *key,
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void *data, int data_size);
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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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#endif
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