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-rw-r--r--fs/btrfs/ctree.h272
1 files changed, 216 insertions, 56 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 66179bc..83a871f 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -30,6 +30,7 @@
#include <linux/kobject.h>
#include <trace/events/btrfs.h>
#include <asm/kmap_types.h>
+#include <linux/pagemap.h>
#include "extent_io.h"
#include "extent_map.h"
#include "async-thread.h"
@@ -360,6 +361,47 @@ struct btrfs_header {
#define BTRFS_LABEL_SIZE 256
/*
+ * just in case we somehow lose the roots and are not able to mount,
+ * we store an array of the roots from previous transactions
+ * in the super.
+ */
+#define BTRFS_NUM_BACKUP_ROOTS 4
+struct btrfs_root_backup {
+ __le64 tree_root;
+ __le64 tree_root_gen;
+
+ __le64 chunk_root;
+ __le64 chunk_root_gen;
+
+ __le64 extent_root;
+ __le64 extent_root_gen;
+
+ __le64 fs_root;
+ __le64 fs_root_gen;
+
+ __le64 dev_root;
+ __le64 dev_root_gen;
+
+ __le64 csum_root;
+ __le64 csum_root_gen;
+
+ __le64 total_bytes;
+ __le64 bytes_used;
+ __le64 num_devices;
+ /* future */
+ __le64 unsed_64[4];
+
+ u8 tree_root_level;
+ u8 chunk_root_level;
+ u8 extent_root_level;
+ u8 fs_root_level;
+ u8 dev_root_level;
+ u8 csum_root_level;
+ /* future and to align */
+ u8 unused_8[10];
+} __attribute__ ((__packed__));
+
+/*
* the super block basically lists the main trees of the FS
* it currently lacks any block count etc etc
*/
@@ -405,6 +447,7 @@ struct btrfs_super_block {
/* future expansion */
__le64 reserved[31];
u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
+ struct btrfs_root_backup super_roots[BTRFS_NUM_BACKUP_ROOTS];
} __attribute__ ((__packed__));
/*
@@ -755,6 +798,8 @@ struct btrfs_space_info {
chunks for this space */
unsigned int chunk_alloc:1; /* set if we are allocating a chunk */
+ unsigned int flush:1; /* set if we are trying to make space */
+
unsigned int force_alloc; /* set if we need to force a chunk
alloc for this space */
@@ -764,20 +809,14 @@ struct btrfs_space_info {
struct list_head block_groups[BTRFS_NR_RAID_TYPES];
spinlock_t lock;
struct rw_semaphore groups_sem;
- atomic_t caching_threads;
+ wait_queue_head_t wait;
};
struct btrfs_block_rsv {
u64 size;
u64 reserved;
- u64 freed[2];
struct btrfs_space_info *space_info;
- struct list_head list;
spinlock_t lock;
- atomic_t usage;
- unsigned int priority:8;
- unsigned int durable:1;
- unsigned int refill_used:1;
unsigned int full:1;
};
@@ -809,7 +848,8 @@ struct btrfs_free_cluster {
enum btrfs_caching_type {
BTRFS_CACHE_NO = 0,
BTRFS_CACHE_STARTED = 1,
- BTRFS_CACHE_FINISHED = 2,
+ BTRFS_CACHE_FAST = 2,
+ BTRFS_CACHE_FINISHED = 3,
};
enum btrfs_disk_cache_state {
@@ -824,6 +864,7 @@ struct btrfs_caching_control {
struct list_head list;
struct mutex mutex;
wait_queue_head_t wait;
+ struct btrfs_work work;
struct btrfs_block_group_cache *block_group;
u64 progress;
atomic_t count;
@@ -837,10 +878,10 @@ struct btrfs_block_group_cache {
spinlock_t lock;
u64 pinned;
u64 reserved;
- u64 reserved_pinned;
u64 bytes_super;
u64 flags;
u64 sectorsize;
+ u64 cache_generation;
unsigned int ro:1;
unsigned int dirty:1;
unsigned int iref:1;
@@ -896,6 +937,10 @@ struct btrfs_fs_info {
spinlock_t block_group_cache_lock;
struct rb_root block_group_cache_tree;
+ /* keep track of unallocated space */
+ spinlock_t free_chunk_lock;
+ u64 free_chunk_space;
+
struct extent_io_tree freed_extents[2];
struct extent_io_tree *pinned_extents;
@@ -913,14 +958,11 @@ struct btrfs_fs_info {
struct btrfs_block_rsv trans_block_rsv;
/* block reservation for chunk tree */
struct btrfs_block_rsv chunk_block_rsv;
+ /* block reservation for delayed operations */
+ struct btrfs_block_rsv delayed_block_rsv;
struct btrfs_block_rsv empty_block_rsv;
- /* list of block reservations that cross multiple transactions */
- struct list_head durable_block_rsv_list;
-
- struct mutex durable_block_rsv_mutex;
-
u64 generation;
u64 last_trans_committed;
@@ -939,8 +981,8 @@ struct btrfs_fs_info {
wait_queue_head_t transaction_blocked_wait;
wait_queue_head_t async_submit_wait;
- struct btrfs_super_block super_copy;
- struct btrfs_super_block super_for_commit;
+ struct btrfs_super_block *super_copy;
+ struct btrfs_super_block *super_for_commit;
struct block_device *__bdev;
struct super_block *sb;
struct inode *btree_inode;
@@ -1032,6 +1074,9 @@ struct btrfs_fs_info {
struct btrfs_workers endio_write_workers;
struct btrfs_workers endio_freespace_worker;
struct btrfs_workers submit_workers;
+ struct btrfs_workers caching_workers;
+ struct btrfs_workers readahead_workers;
+
/*
* fixup workers take dirty pages that didn't properly go through
* the cow mechanism and make them safe to write. It happens
@@ -1114,6 +1159,13 @@ struct btrfs_fs_info {
u64 fs_state;
struct btrfs_delayed_root *delayed_root;
+
+ /* readahead tree */
+ spinlock_t reada_lock;
+ struct radix_tree_root reada_tree;
+
+ /* next backup root to be overwritten */
+ int backup_root_index;
};
/*
@@ -1219,7 +1271,9 @@ struct btrfs_root {
* right now this just gets used so that a root has its own devid
* for stat. It may be used for more later
*/
- struct super_block anon_super;
+ dev_t anon_dev;
+
+ int force_cow;
};
struct btrfs_ioctl_defrag_range_args {
@@ -1358,6 +1412,7 @@ struct btrfs_ioctl_defrag_range_args {
#define BTRFS_MOUNT_ENOSPC_DEBUG (1 << 15)
#define BTRFS_MOUNT_AUTO_DEFRAG (1 << 16)
#define BTRFS_MOUNT_INODE_MAP_CACHE (1 << 17)
+#define BTRFS_MOUNT_RECOVERY (1 << 18)
#define btrfs_clear_opt(o, opt) ((o) &= ~BTRFS_MOUNT_##opt)
#define btrfs_set_opt(o, opt) ((o) |= BTRFS_MOUNT_##opt)
@@ -1410,17 +1465,15 @@ void btrfs_set_##name(struct extent_buffer *eb, type *s, u##bits val);
#define BTRFS_SETGET_HEADER_FUNCS(name, type, member, bits) \
static inline u##bits btrfs_##name(struct extent_buffer *eb) \
{ \
- type *p = kmap_atomic(eb->first_page, KM_USER0); \
+ type *p = page_address(eb->first_page); \
u##bits res = le##bits##_to_cpu(p->member); \
- kunmap_atomic(p, KM_USER0); \
return res; \
} \
static inline void btrfs_set_##name(struct extent_buffer *eb, \
u##bits val) \
{ \
- type *p = kmap_atomic(eb->first_page, KM_USER0); \
+ type *p = page_address(eb->first_page); \
p->member = cpu_to_le##bits(val); \
- kunmap_atomic(p, KM_USER0); \
}
#define BTRFS_SETGET_STACK_FUNCS(name, type, member, bits) \
@@ -1975,6 +2028,55 @@ static inline bool btrfs_root_readonly(struct btrfs_root *root)
return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_RDONLY)) != 0;
}
+/* struct btrfs_root_backup */
+BTRFS_SETGET_STACK_FUNCS(backup_tree_root, struct btrfs_root_backup,
+ tree_root, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_tree_root_gen, struct btrfs_root_backup,
+ tree_root_gen, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_tree_root_level, struct btrfs_root_backup,
+ tree_root_level, 8);
+
+BTRFS_SETGET_STACK_FUNCS(backup_chunk_root, struct btrfs_root_backup,
+ chunk_root, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_chunk_root_gen, struct btrfs_root_backup,
+ chunk_root_gen, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_chunk_root_level, struct btrfs_root_backup,
+ chunk_root_level, 8);
+
+BTRFS_SETGET_STACK_FUNCS(backup_extent_root, struct btrfs_root_backup,
+ extent_root, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_extent_root_gen, struct btrfs_root_backup,
+ extent_root_gen, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_extent_root_level, struct btrfs_root_backup,
+ extent_root_level, 8);
+
+BTRFS_SETGET_STACK_FUNCS(backup_fs_root, struct btrfs_root_backup,
+ fs_root, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_fs_root_gen, struct btrfs_root_backup,
+ fs_root_gen, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_fs_root_level, struct btrfs_root_backup,
+ fs_root_level, 8);
+
+BTRFS_SETGET_STACK_FUNCS(backup_dev_root, struct btrfs_root_backup,
+ dev_root, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_dev_root_gen, struct btrfs_root_backup,
+ dev_root_gen, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_dev_root_level, struct btrfs_root_backup,
+ dev_root_level, 8);
+
+BTRFS_SETGET_STACK_FUNCS(backup_csum_root, struct btrfs_root_backup,
+ csum_root, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_csum_root_gen, struct btrfs_root_backup,
+ csum_root_gen, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_csum_root_level, struct btrfs_root_backup,
+ csum_root_level, 8);
+BTRFS_SETGET_STACK_FUNCS(backup_total_bytes, struct btrfs_root_backup,
+ total_bytes, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_bytes_used, struct btrfs_root_backup,
+ bytes_used, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_num_devices, struct btrfs_root_backup,
+ num_devices, 64);
+
/* struct btrfs_super_block */
BTRFS_SETGET_STACK_FUNCS(super_bytenr, struct btrfs_super_block, bytenr, 64);
@@ -2126,14 +2228,30 @@ static inline bool btrfs_mixed_space_info(struct btrfs_space_info *space_info)
(space_info->flags & BTRFS_BLOCK_GROUP_DATA));
}
+static inline gfp_t btrfs_alloc_write_mask(struct address_space *mapping)
+{
+ return mapping_gfp_mask(mapping) & ~__GFP_FS;
+}
+
/* extent-tree.c */
static inline u64 btrfs_calc_trans_metadata_size(struct btrfs_root *root,
- int num_items)
+ unsigned num_items)
{
return (root->leafsize + root->nodesize * (BTRFS_MAX_LEVEL - 1)) *
3 * num_items;
}
+/*
+ * Doing a truncate won't result in new nodes or leaves, just what we need for
+ * COW.
+ */
+static inline u64 btrfs_calc_trunc_metadata_size(struct btrfs_root *root,
+ unsigned num_items)
+{
+ return (root->leafsize + root->nodesize * (BTRFS_MAX_LEVEL - 1)) *
+ num_items;
+}
+
void btrfs_put_block_group(struct btrfs_block_group_cache *cache);
int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
struct btrfs_root *root, unsigned long count);
@@ -2143,6 +2261,9 @@ int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
u64 num_bytes, u64 *refs, u64 *flags);
int btrfs_pin_extent(struct btrfs_root *root,
u64 bytenr, u64 num, int reserved);
+int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ u64 bytenr, u64 num_bytes);
int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 objectid, u64 offset, u64 bytenr);
@@ -2193,8 +2314,8 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans,
u64 root_objectid, u64 owner, u64 offset);
int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len);
-int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
- u64 num_bytes, int reserve, int sinfo);
+int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
+ u64 start, u64 len);
int btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
struct btrfs_root *root);
int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
@@ -2222,9 +2343,6 @@ void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *ionde);
void btrfs_clear_space_info_full(struct btrfs_fs_info *info);
int btrfs_check_data_free_space(struct inode *inode, u64 bytes);
void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes);
-int btrfs_trans_reserve_metadata(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
- int num_items);
void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
struct btrfs_root *root);
int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
@@ -2240,25 +2358,26 @@ void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv);
struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root);
void btrfs_free_block_rsv(struct btrfs_root *root,
struct btrfs_block_rsv *rsv);
-void btrfs_add_durable_block_rsv(struct btrfs_fs_info *fs_info,
- struct btrfs_block_rsv *rsv);
-int btrfs_block_rsv_add(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
+int btrfs_block_rsv_add(struct btrfs_root *root,
struct btrfs_block_rsv *block_rsv,
u64 num_bytes);
-int btrfs_block_rsv_check(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
+int btrfs_block_rsv_add_noflush(struct btrfs_root *root,
+ struct btrfs_block_rsv *block_rsv,
+ u64 num_bytes);
+int btrfs_block_rsv_check(struct btrfs_root *root,
+ struct btrfs_block_rsv *block_rsv, int min_factor);
+int btrfs_block_rsv_refill(struct btrfs_root *root,
struct btrfs_block_rsv *block_rsv,
- u64 min_reserved, int min_factor);
+ u64 min_reserved);
+int btrfs_block_rsv_refill_noflush(struct btrfs_root *root,
+ struct btrfs_block_rsv *block_rsv,
+ u64 min_reserved);
int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
struct btrfs_block_rsv *dst_rsv,
u64 num_bytes);
void btrfs_block_rsv_release(struct btrfs_root *root,
struct btrfs_block_rsv *block_rsv,
u64 num_bytes);
-int btrfs_truncate_reserve_metadata(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
- struct btrfs_block_rsv *rsv);
int btrfs_set_block_group_ro(struct btrfs_root *root,
struct btrfs_block_group_cache *cache);
int btrfs_set_block_group_rw(struct btrfs_root *root,
@@ -2330,7 +2449,7 @@ struct btrfs_path *btrfs_alloc_path(void);
void btrfs_free_path(struct btrfs_path *p);
void btrfs_set_path_blocking(struct btrfs_path *p);
void btrfs_clear_path_blocking(struct btrfs_path *p,
- struct extent_buffer *held);
+ struct extent_buffer *held, int held_rw);
void btrfs_unlock_up_safe(struct btrfs_path *p, int level);
int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
@@ -2365,8 +2484,8 @@ static inline int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path);
int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path);
int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf);
-int btrfs_drop_snapshot(struct btrfs_root *root,
- struct btrfs_block_rsv *block_rsv, int update_ref);
+void btrfs_drop_snapshot(struct btrfs_root *root,
+ struct btrfs_block_rsv *block_rsv, int update_ref);
int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *node,
@@ -2379,6 +2498,18 @@ static inline int btrfs_fs_closing(struct btrfs_fs_info *fs_info)
smp_mb();
return fs_info->closing;
}
+static inline void free_fs_info(struct btrfs_fs_info *fs_info)
+{
+ kfree(fs_info->delayed_root);
+ kfree(fs_info->extent_root);
+ kfree(fs_info->tree_root);
+ kfree(fs_info->chunk_root);
+ kfree(fs_info->dev_root);
+ kfree(fs_info->csum_root);
+ kfree(fs_info->super_copy);
+ kfree(fs_info->super_for_commit);
+ kfree(fs_info);
+}
/* root-item.c */
int btrfs_find_root_ref(struct btrfs_root *tree_root,
@@ -2404,8 +2535,8 @@ int btrfs_find_last_root(struct btrfs_root *root, u64 objectid, struct
btrfs_root_item *item, struct btrfs_key *key);
int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid);
int btrfs_find_orphan_roots(struct btrfs_root *tree_root);
-int btrfs_set_root_node(struct btrfs_root_item *item,
- struct extent_buffer *node);
+void btrfs_set_root_node(struct btrfs_root_item *item,
+ struct extent_buffer *node);
void btrfs_check_and_init_root_item(struct btrfs_root_item *item);
/* dir-item.c */
@@ -2510,6 +2641,9 @@ int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
struct list_head *list, int search_commit);
/* inode.c */
+struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
+ size_t pg_offset, u64 start, u64 len,
+ int create);
/* RHEL and EL kernels have a patch that renames PG_checked to FsMisc */
#if defined(ClearPageFsMisc) && !defined(ClearPageChecked)
@@ -2518,6 +2652,14 @@ int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
#define PageChecked PageFsMisc
#endif
+/* This forces readahead on a given range of bytes in an inode */
+static inline void btrfs_force_ra(struct address_space *mapping,
+ struct file_ra_state *ra, struct file *file,
+ pgoff_t offset, unsigned long req_size)
+{
+ page_cache_sync_readahead(mapping, ra, file, offset, req_size);
+}
+
struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry);
int btrfs_set_inode_index(struct inode *dir, u64 *index);
int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
@@ -2546,14 +2688,12 @@ int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
size_t size, struct bio *bio, unsigned long bio_flags);
-unsigned long btrfs_force_ra(struct address_space *mapping,
- struct file_ra_state *ra, struct file *file,
- pgoff_t offset, pgoff_t last_index);
int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
int btrfs_readpage(struct file *file, struct page *page);
void btrfs_evict_inode(struct inode *inode);
int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc);
-void btrfs_dirty_inode(struct inode *inode, int flags);
+int btrfs_dirty_inode(struct inode *inode);
+int btrfs_update_time(struct file *file);
struct inode *btrfs_alloc_inode(struct super_block *sb);
void btrfs_destroy_inode(struct inode *inode);
int btrfs_drop_inode(struct inode *inode);
@@ -2571,11 +2711,6 @@ int btrfs_update_inode(struct btrfs_trans_handle *trans,
int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode);
int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode);
int btrfs_orphan_cleanup(struct btrfs_root *root);
-void btrfs_orphan_pre_snapshot(struct btrfs_trans_handle *trans,
- struct btrfs_pending_snapshot *pending,
- u64 *bytes_to_reserve);
-void btrfs_orphan_post_snapshot(struct btrfs_trans_handle *trans,
- struct btrfs_pending_snapshot *pending);
void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root);
int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size);
@@ -2602,7 +2737,7 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
struct inode *inode);
int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info);
-int btrfs_sync_file(struct file *file, int datasync);
+int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync);
int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
int skip_pinned);
extern const struct file_operations btrfs_file_operations;
@@ -2642,13 +2777,22 @@ do { \
/* acl.c */
#ifdef CONFIG_BTRFS_FS_POSIX_ACL
-int btrfs_check_acl(struct inode *inode, int mask, unsigned int flags);
-#else
-#define btrfs_check_acl NULL
-#endif
+struct posix_acl *btrfs_get_acl(struct inode *inode, int type);
int btrfs_init_acl(struct btrfs_trans_handle *trans,
struct inode *inode, struct inode *dir);
int btrfs_acl_chmod(struct inode *inode);
+#else
+#define btrfs_get_acl NULL
+static inline int btrfs_init_acl(struct btrfs_trans_handle *trans,
+ struct inode *inode, struct inode *dir)
+{
+ return 0;
+}
+static inline int btrfs_acl_chmod(struct inode *inode)
+{
+ return 0;
+}
+#endif
/* relocation.c */
int btrfs_relocate_block_group(struct btrfs_root *root, u64 group_start);
@@ -2680,4 +2824,20 @@ int btrfs_scrub_cancel_devid(struct btrfs_root *root, u64 devid);
int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
struct btrfs_scrub_progress *progress);
+/* reada.c */
+struct reada_control {
+ struct btrfs_root *root; /* tree to prefetch */
+ struct btrfs_key key_start;
+ struct btrfs_key key_end; /* exclusive */
+ atomic_t elems;
+ struct kref refcnt;
+ wait_queue_head_t wait;
+};
+struct reada_control *btrfs_reada_add(struct btrfs_root *root,
+ struct btrfs_key *start, struct btrfs_key *end);
+int btrfs_reada_wait(void *handle);
+void btrfs_reada_detach(void *handle);
+int btree_readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
+ u64 start, int err);
+
#endif