linux/fs/btrfs/extent_map.h
Josef Bacik 201a903894 Btrfs: do not allow logged extents to be merged or removed
We drop the extent map tree lock while we're logging extents, so somebody
could come in and merge another extent into this one and screw up our
logging, or they could even remove us from the list which would keep us from
logging the extent or freeing our ref on it, so we need to make sure to not
clear LOGGING until after the extent is logged, and then we can merge it to
adjacent extents.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-01-24 12:49:48 -05:00

76 lines
2.1 KiB
C

#ifndef __EXTENTMAP__
#define __EXTENTMAP__
#include <linux/rbtree.h>
#define EXTENT_MAP_LAST_BYTE (u64)-4
#define EXTENT_MAP_HOLE (u64)-3
#define EXTENT_MAP_INLINE (u64)-2
#define EXTENT_MAP_DELALLOC (u64)-1
/* bits for the flags field */
#define EXTENT_FLAG_PINNED 0 /* this entry not yet on disk, don't free it */
#define EXTENT_FLAG_COMPRESSED 1
#define EXTENT_FLAG_VACANCY 2 /* no file extent item found */
#define EXTENT_FLAG_PREALLOC 3 /* pre-allocated extent */
#define EXTENT_FLAG_LOGGING 4 /* Logging this extent */
#define EXTENT_FLAG_FILLING 5 /* Filling in a preallocated extent */
struct extent_map {
struct rb_node rb_node;
/* all of these are in bytes */
u64 start;
u64 len;
u64 mod_start;
u64 mod_len;
u64 orig_start;
u64 orig_block_len;
u64 block_start;
u64 block_len;
u64 generation;
unsigned long flags;
struct block_device *bdev;
atomic_t refs;
unsigned int in_tree;
unsigned int compress_type;
struct list_head list;
};
struct extent_map_tree {
struct rb_root map;
struct list_head modified_extents;
rwlock_t lock;
};
static inline u64 extent_map_end(struct extent_map *em)
{
if (em->start + em->len < em->start)
return (u64)-1;
return em->start + em->len;
}
static inline u64 extent_map_block_end(struct extent_map *em)
{
if (em->block_start + em->block_len < em->block_start)
return (u64)-1;
return em->block_start + em->block_len;
}
void extent_map_tree_init(struct extent_map_tree *tree);
struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
u64 start, u64 len);
int add_extent_mapping(struct extent_map_tree *tree,
struct extent_map *em);
int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em);
struct extent_map *alloc_extent_map(void);
void free_extent_map(struct extent_map *em);
int __init extent_map_init(void);
void extent_map_exit(void);
int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len, u64 gen);
void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em);
struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
u64 start, u64 len);
#endif