fs/jfs/jfs_metapage.h

Source file repositories/reference/linux-study-clean/fs/jfs/jfs_metapage.h

File Facts

System
Linux kernel
Corpus path
fs/jfs/jfs_metapage.h
Extension
.h
Size
3630 bytes
Lines
143
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 metapage {
	/* Common logsyncblk prefix (see jfs_logmgr.h) */
	u16 xflag;
	u16 unused;
	lid_t lid;
	int lsn;
	struct list_head synclist;
	/* End of logsyncblk prefix */

	unsigned long flag;	/* See Below */
	unsigned long count;	/* Reference count */
	void *data;		/* Data pointer */
	sector_t index;		/* block address of page */
	wait_queue_head_t wait;

	/* implementation */
	struct folio *folio;
	struct super_block *sb;
	unsigned int logical_size;

	/* Journal management */
	int clsn;
	int nohomeok;
	struct jfs_log *log;
};

/* metapage flag */
#define META_locked	0
#define META_dirty	2
#define META_sync	3
#define META_discard	4
#define META_forcewrite	5
#define META_io		6

#define mark_metapage_dirty(mp) set_bit(META_dirty, &(mp)->flag)

/* function prototypes */
extern int metapage_init(void);
extern void metapage_exit(void);
extern struct metapage *__get_metapage(struct inode *inode,
				  unsigned long lblock, unsigned int size,
				  int absolute, unsigned long new);

#define read_metapage(inode, lblock, size, absolute)\
	 __get_metapage(inode, lblock, size, absolute, false)

#define get_metapage(inode, lblock, size, absolute)\
	 __get_metapage(inode, lblock, size, absolute, true)

extern void release_metapage(struct metapage *);
extern void grab_metapage(struct metapage *);
extern void force_metapage(struct metapage *);

/*
 * hold_metapage and put_metapage are used in conjunction.  The page lock
 * is not dropped between the two, so no other threads can get or release
 * the metapage
 */
extern void hold_metapage(struct metapage *);
extern void put_metapage(struct metapage *);

static inline void write_metapage(struct metapage *mp)
{
	set_bit(META_dirty, &mp->flag);
	release_metapage(mp);
}

static inline void flush_metapage(struct metapage *mp)
{
	set_bit(META_sync, &mp->flag);
	write_metapage(mp);
}

static inline void discard_metapage(struct metapage *mp)
{
	clear_bit(META_dirty, &mp->flag);
	set_bit(META_discard, &mp->flag);
	release_metapage(mp);
}

static inline void metapage_nohomeok(struct metapage *mp)
{
	struct folio *folio = mp->folio;
	folio_lock(folio);
	if (!mp->nohomeok++) {
		mark_metapage_dirty(mp);
		folio_get(folio);
		folio_wait_writeback(folio);
	}
	folio_unlock(folio);

Annotation

Implementation Notes