mirror of
https://github.com/torvalds/linux.git
synced 2024-09-27 02:13:14 +00:00
a1ed835e1a
Data COW means that whenever we write to a file, we replace any old extent pointers with new ones. There was a window where a readpage might find the old extent pointers on disk and cache them in the extent_map tree in ram in the middle of a given write replacing them. Even though both the readpage and the write had their respective bytes in the file locked, the extent readpage inserts may cover more bytes than it had locked down. This commit closes the race by keeping the new extent pinned in the extent map tree until after the on-disk btree is properly setup with the new extent pointers. Signed-off-by: Chris Mason <chris.mason@oracle.com>
64 lines
1.6 KiB
C
64 lines
1.6 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 */
|
|
|
|
struct extent_map {
|
|
struct rb_node rb_node;
|
|
|
|
/* all of these are in bytes */
|
|
u64 start;
|
|
u64 len;
|
|
u64 orig_start;
|
|
u64 block_start;
|
|
u64 block_len;
|
|
unsigned long flags;
|
|
struct block_device *bdev;
|
|
atomic_t refs;
|
|
int in_tree;
|
|
};
|
|
|
|
struct extent_map_tree {
|
|
struct rb_root map;
|
|
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, gfp_t mask);
|
|
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(gfp_t mask);
|
|
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);
|
|
#endif
|