ref: b5d191e8cfa4fac05a02ea309df2541a2652ff23
dir: /extents.h/
/*
* an ordered linked list sorted by block number (->low, ->high).
* ->big or ->small sorted by size and then block number.
*/
typedef struct Extent Extent;
typedef struct Extents Extents;
/*
When allocating blocks from extents:
1. Of all the extents with the len we need, pick the extent with the lowest blkno.
2. If no extent of the len we need is available, then break up the smallest extent.
*/
struct Extent {
struct Extent *low, *high; /* sorted by start */
u64 start; /* where this extent starts from */
u64 len; /* how many units in this extent */
/* circular least recently used linked list limited to Nlru items */
struct Extent *prev, *next;
};
struct Extents {
Extent *head; /* find the first block in a jiffy */
QLock lck;
u32 n; /* number of extents */
Rendez isempty; /* fully used, nothing available */
u8 nlru; /* number of items in the lru linked list */
Extent *lru; /* least recently used extent in the circular lru linked list */
};
extern int chatty9p;
void *emalloc(u32 sz);
s8 *estrdup(s8 *s);
void panic(char *fmt, ...);
s8 find(Extents *es, u64 bno);
Extent *add(Extents *es, u64 blkno, u64 len);
void showblocknos(int fd, Extents *es);
void showextents(int fd, char *msg, Extents *es);
s32 sizeofextents(Extents *es);
s32 saveextents(Extents *es, s8 *buf, u32 nbuf);
s32 loadextents(Extents *es, s8 *buf, u32 nbuf);
u64 balloc(Extents *es, u64 len);
void bfree(Extents *es, u64 blkno, u64 len);
u64 nfrees(Extents *es);
Extent *lowest(Extents *es);
void initextents(Extents *es);