fs/xfs/libxfs/xfs_refcount.h

Source file repositories/reference/linux-study-clean/fs/xfs/libxfs/xfs_refcount.h

File Facts

System
Linux kernel
Corpus path
fs/xfs/libxfs/xfs_refcount.h
Extension
.h
Size
5142 bytes
Lines
147
Domain
Core OS
Bucket
VFS And Filesystem Core
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

struct xfs_refcount_intent {
	struct list_head			ri_list;
	struct xfs_group			*ri_group;
	enum xfs_refcount_intent_type		ri_type;
	xfs_extlen_t				ri_blockcount;
	xfs_fsblock_t				ri_startblock;
	bool					ri_realtime;
};

/* Check that the refcount is appropriate for the record domain. */
static inline bool
xfs_refcount_check_domain(
	const struct xfs_refcount_irec	*irec)
{
	if (irec->rc_domain == XFS_REFC_DOMAIN_COW && irec->rc_refcount != 1)
		return false;
	if (irec->rc_domain == XFS_REFC_DOMAIN_SHARED && irec->rc_refcount < 2)
		return false;
	return true;
}

void xfs_refcount_increase_extent(struct xfs_trans *tp, bool isrt,
		struct xfs_bmbt_irec *irec);
void xfs_refcount_decrease_extent(struct xfs_trans *tp, bool isrt,
		struct xfs_bmbt_irec *irec);

int xfs_refcount_finish_one(struct xfs_trans *tp,
		struct xfs_refcount_intent *ri, struct xfs_btree_cur **pcur);
int xfs_rtrefcount_finish_one(struct xfs_trans *tp,
		struct xfs_refcount_intent *ri, struct xfs_btree_cur **pcur);

extern int xfs_refcount_find_shared(struct xfs_btree_cur *cur,
		xfs_agblock_t agbno, xfs_extlen_t aglen, xfs_agblock_t *fbno,
		xfs_extlen_t *flen, bool find_end_of_shared);

void xfs_refcount_alloc_cow_extent(struct xfs_trans *tp, bool isrt,
		xfs_fsblock_t fsb, xfs_extlen_t len);
void xfs_refcount_free_cow_extent(struct xfs_trans *tp, bool isrt,
		xfs_fsblock_t fsb, xfs_extlen_t len);
int xfs_refcount_recover_cow_leftovers(struct xfs_group *xg);

/*
 * While we're adjusting the refcounts records of an extent, we have
 * to keep an eye on the number of extents we're dirtying -- run too
 * many in a single transaction and we'll exceed the transaction's
 * reservation and crash the fs.  Each record adds 12 bytes to the
 * log (plus any key updates) so we'll conservatively assume 32 bytes
 * per record.  We must also leave space for btree splits on both ends
 * of the range and space for the CUD and a new CUI.
 *
 * Each EFI that we attach to the transaction is assumed to consume ~32 bytes.
 * This is a low estimate for an EFI tracking a single extent (16 bytes for the
 * EFI header, 16 for the extent, and 12 for the xlog op header), but the
 * estimate is acceptable if there's more than one extent being freed.
 * In the worst case of freeing every other block during a refcount decrease
 * operation, we amortize the space used for one EFI log item across 16
 * extents.
 */
#define XFS_REFCOUNT_ITEM_OVERHEAD	32

extern int xfs_refcount_has_records(struct xfs_btree_cur *cur,
		enum xfs_refc_domain domain, xfs_agblock_t bno,
		xfs_extlen_t len, enum xbtree_recpacking *outcome);
union xfs_btree_rec;
extern void xfs_refcount_btrec_to_irec(const union xfs_btree_rec *rec,
		struct xfs_refcount_irec *irec);
xfs_failaddr_t xfs_refcount_check_irec(struct xfs_perag *pag,
		const struct xfs_refcount_irec *irec);
xfs_failaddr_t xfs_rtrefcount_check_irec(struct xfs_rtgroup *rtg,
		const struct xfs_refcount_irec *irec);
extern int xfs_refcount_insert(struct xfs_btree_cur *cur,
		struct xfs_refcount_irec *irec, int *stat);

extern struct kmem_cache	*xfs_refcount_intent_cache;

int __init xfs_refcount_intent_init_cache(void);
void xfs_refcount_intent_destroy_cache(void);

typedef int (*xfs_refcount_query_range_fn)(
	struct xfs_btree_cur		*cur,
	const struct xfs_refcount_irec	*rec,
	void				*priv);

int xfs_refcount_query_range(struct xfs_btree_cur *cur,
		const struct xfs_refcount_irec *low_rec,
		const struct xfs_refcount_irec *high_rec,
		xfs_refcount_query_range_fn fn, void *priv);

#endif	/* __XFS_REFCOUNT_H__ */

Annotation

Implementation Notes