cregit-Linux how code gets into the kernel

Release 4.10 fs/xfs/xfs_buf.h

Directory: fs/xfs
/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#ifndef __XFS_BUF_H__

#define __XFS_BUF_H__

#include <linux/list.h>
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/dax.h>
#include <linux/buffer_head.h>
#include <linux/uio.h>
#include <linux/list_lru.h>

/*
 *      Base types
 */


#define XFS_BUF_DADDR_NULL	((xfs_daddr_t) (-1LL))

typedef enum {
	
XBRW_READ = 1,			/* transfer into target memory */
	
XBRW_WRITE = 2,			/* transfer from target memory */
	
XBRW_ZERO = 3,			/* Zero target memory */
} 
xfs_buf_rw_t;


#define XBF_READ	 (1 << 0) 
/* buffer intended for reading from device */

#define XBF_WRITE	 (1 << 1) 
/* buffer intended for writing to device */

#define XBF_READ_AHEAD	 (1 << 2) 
/* asynchronous read-ahead */

#define XBF_NO_IOACCT	 (1 << 3) 
/* bypass I/O accounting (non-LRU bufs) */

#define XBF_ASYNC	 (1 << 4) 
/* initiator will not wait for completion */

#define XBF_DONE	 (1 << 5) 
/* all pages in the buffer uptodate */

#define XBF_STALE	 (1 << 6) 
/* buffer has been staled, do not find it */

#define XBF_WRITE_FAIL	 (1 << 24)
/* async writes have failed on this buffer */

/* I/O hints for the BIO layer */

#define XBF_SYNCIO	 (1 << 10)
/* treat this buffer as synchronous I/O */

#define XBF_FUA		 (1 << 11)
/* force cache write through mode */

#define XBF_FLUSH	 (1 << 12)
/* flush the disk cache before a write */

/* flags used only as arguments to access routines */

#define XBF_TRYLOCK	 (1 << 16)
/* lock requested, but do not wait */

#define XBF_UNMAPPED	 (1 << 17)
/* do not map the buffer */

/* flags used only internally */

#define _XBF_PAGES	 (1 << 20)
/* backed by refcounted pages */

#define _XBF_KMEM	 (1 << 21)
/* backed by heap memory */

#define _XBF_DELWRI_Q	 (1 << 22)
/* buffer on a delwri queue */

#define _XBF_COMPOUND	 (1 << 23)
/* compound buffer */

#define _XBF_IN_FLIGHT	 (1 << 25) 
/* I/O in flight, for accounting purposes */


typedef unsigned int xfs_buf_flags_t;


#define XFS_BUF_FLAGS \
	{ XBF_READ,             "READ" }, \
        { XBF_WRITE,            "WRITE" }, \
        { XBF_READ_AHEAD,       "READ_AHEAD" }, \
        { XBF_NO_IOACCT,        "NO_IOACCT" }, \
        { XBF_ASYNC,            "ASYNC" }, \
        { XBF_DONE,             "DONE" }, \
        { XBF_STALE,            "STALE" }, \
        { XBF_WRITE_FAIL,       "WRITE_FAIL" }, \
        { XBF_SYNCIO,           "SYNCIO" }, \
        { XBF_FUA,              "FUA" }, \
        { XBF_FLUSH,            "FLUSH" }, \
        { XBF_TRYLOCK,          "TRYLOCK" },	/* should never be set */\
        { XBF_UNMAPPED,         "UNMAPPED" },	/* ditto */\
        { _XBF_PAGES,           "PAGES" }, \
        { _XBF_KMEM,            "KMEM" }, \
        { _XBF_DELWRI_Q,        "DELWRI_Q" }, \
        { _XBF_COMPOUND,        "COMPOUND" }, \
        { _XBF_IN_FLIGHT,       "IN_FLIGHT" }


/*
 * Internal state flags.
 */

#define XFS_BSTATE_DISPOSE	 (1 << 0)	
/* buffer being discarded */

/*
 * The xfs_buftarg contains 2 notions of "sector size" -
 *
 * 1) The metadata sector size, which is the minimum unit and
 *    alignment of IO which will be performed by metadata operations.
 * 2) The device logical sector size
 *
 * The first is specified at mkfs time, and is stored on-disk in the
 * superblock's sb_sectsize.
 *
 * The latter is derived from the underlying device, and controls direct IO
 * alignment constraints.
 */

typedef struct xfs_buftarg {
	
dev_t			bt_dev;
	
struct block_device	*bt_bdev;
	
struct backing_dev_info	*bt_bdi;
	
struct xfs_mount	*bt_mount;
	
unsigned int		bt_meta_sectorsize;
	
size_t			bt_meta_sectormask;
	
size_t			bt_logical_sectorsize;
	
size_t			bt_logical_sectormask;

	/* LRU control structures */
	
struct shrinker		bt_shrinker;
	
struct list_lru		bt_lru;

	
struct percpu_counter	bt_io_count;
} 
xfs_buftarg_t;

struct xfs_buf;

typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);



#define XB_PAGES	2


struct xfs_buf_map {
	
xfs_daddr_t		bm_bn;	/* block number for I/O */
	
int			bm_len;	/* size of I/O */
};


#define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
	struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };


struct xfs_buf_ops {
	
char *name;
	
void (*verify_read)(struct xfs_buf *);
	
void (*verify_write)(struct xfs_buf *);
};


typedef struct xfs_buf {
	/*
         * first cacheline holds all the fields needed for an uncontended cache
         * hit to be fully processed. The semaphore straddles the cacheline
         * boundary, but the counter and lock sits on the first cacheline,
         * which is the only bit that is touched if we hit the semaphore
         * fast-path on locking.
         */
	
struct rhash_head	b_rhash_head;	/* pag buffer hash node */
	
xfs_daddr_t		b_bn;		/* block number of buffer */
	
int			b_length;	/* size of buffer in BBs */
	
atomic_t		b_hold;		/* reference count */
	
atomic_t		b_lru_ref;	/* lru reclaim ref count */
	
xfs_buf_flags_t		b_flags;	/* status flags */
	
struct semaphore	b_sema;		/* semaphore for lockables */

	/*
         * concurrent access to b_lru and b_lru_flags are protected by
         * bt_lru_lock and not by b_sema
         */
	
struct list_head	b_lru;		/* lru list */
	
spinlock_t		b_lock;		/* internal state lock */
	
unsigned int		b_state;	/* internal state flags */
	
int			b_io_error;	/* internal IO error state */
	
wait_queue_head_t	b_waiters;	/* unpin waiters */
	
struct list_head	b_list;
	
struct xfs_perag	*b_pag;		/* contains rbtree root */
	
xfs_buftarg_t		*b_target;	/* buffer target (device) */
	
void			*b_addr;	/* virtual address of buffer */
	
struct work_struct	b_ioend_work;
	
struct workqueue_struct	*b_ioend_wq;	/* I/O completion wq */
	
xfs_buf_iodone_t	b_iodone;	/* I/O completion function */
	
struct completion	b_iowait;	/* queue for I/O waiters */
	
void			*b_fspriv;
	
struct xfs_trans	*b_transp;
	
struct page		**b_pages;	/* array of page pointers */
	
struct page		*b_page_array[XB_PAGES]; /* inline pages */
	
struct xfs_buf_map	*b_maps;	/* compound buffer map */
	
struct xfs_buf_map	__b_map;	/* inline compound buffer map */
	
int			b_map_count;
	
int			b_io_length;	/* IO size in BBs */
	
atomic_t		b_pin_count;	/* pin count */
	
atomic_t		b_io_remaining;	/* #outstanding I/O requests */
	
unsigned int		b_page_count;	/* size of page array */
	
unsigned int		b_offset;	/* page offset in first page */
	
int			b_error;	/* error code on I/O */

	/*
         * async write failure retry count. Initialised to zero on the first
         * failure, then when it exceeds the maximum configured without a
         * success the write is considered to be failed permanently and the
         * iodone handler will take appropriate action.
         *
         * For retry timeouts, we record the jiffie of the first failure. This
         * means that we can change the retry timeout for buffers already under
         * I/O and thus avoid getting stuck in a retry loop with a long timeout.
         *
         * last_error is used to ensure that we are getting repeated errors, not
         * different errors. e.g. a block device might change ENOSPC to EIO when
         * a failure timeout occurs, so we want to re-initialise the error
         * retry behaviour appropriately when that happens.
         */
	
int			b_retries;
	
unsigned long		b_first_retry_time; /* in jiffies */
	
int			b_last_error;

	
const struct xfs_buf_ops	*b_ops;

#ifdef XFS_BUF_LOCK_TRACKING
	
int			b_last_holder;
#endif
} 
xfs_buf_t;

/* Finding and Reading Buffers */
struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target,
			      struct xfs_buf_map *map, int nmaps,
			      xfs_buf_flags_t flags, struct xfs_buf *new_bp);


static inline struct xfs_buf * xfs_incore( struct xfs_buftarg *target, xfs_daddr_t blkno, size_t numblks, xfs_buf_flags_t flags) { DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); return _xfs_buf_find(target, &map, 1, flags, NULL); }

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struct xfs_buf *_xfs_buf_alloc(struct xfs_buftarg *target, struct xfs_buf_map *map, int nmaps, xfs_buf_flags_t flags);
static inline struct xfs_buf * xfs_buf_alloc( struct xfs_buftarg *target, xfs_daddr_t blkno, size_t numblks, xfs_buf_flags_t flags) { DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); return _xfs_buf_alloc(target, &map, 1, flags); }

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struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target, struct xfs_buf_map *map, int nmaps, xfs_buf_flags_t flags); struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target, struct xfs_buf_map *map, int nmaps, xfs_buf_flags_t flags, const struct xfs_buf_ops *ops); void xfs_buf_readahead_map(struct xfs_buftarg *target, struct xfs_buf_map *map, int nmaps, const struct xfs_buf_ops *ops);
static inline struct xfs_buf * xfs_buf_get( struct xfs_buftarg *target, xfs_daddr_t blkno, size_t numblks, xfs_buf_flags_t flags) { DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); return xfs_buf_get_map(target, &map, 1, flags); }

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static inline struct xfs_buf * xfs_buf_read( struct xfs_buftarg *target, xfs_daddr_t blkno, size_t numblks, xfs_buf_flags_t flags, const struct xfs_buf_ops *ops) { DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); return xfs_buf_read_map(target, &map, 1, flags, ops); }

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Total53100.00%7100.00%


static inline void xfs_buf_readahead( struct xfs_buftarg *target, xfs_daddr_t blkno, size_t numblks, const struct xfs_buf_ops *ops) { DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); return xfs_buf_readahead_map(target, &map, 1, ops); }

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struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks); void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks); int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length); struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks, int flags); int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr, size_t numblks, int flags, struct xfs_buf **bpp, const struct xfs_buf_ops *ops); void xfs_buf_hold(struct xfs_buf *bp); /* Releasing Buffers */ extern void xfs_buf_free(xfs_buf_t *); extern void xfs_buf_rele(xfs_buf_t *); /* Locking and Unlocking Buffers */ extern int xfs_buf_trylock(xfs_buf_t *); extern void xfs_buf_lock(xfs_buf_t *); extern void xfs_buf_unlock(xfs_buf_t *); #define xfs_buf_islocked(bp) \ ((bp)->b_sema.count <= 0) /* Buffer Read and Write Routines */ extern int xfs_bwrite(struct xfs_buf *bp); extern void xfs_buf_ioend(struct xfs_buf *bp); extern void xfs_buf_ioerror(xfs_buf_t *, int); extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func); extern void xfs_buf_submit(struct xfs_buf *bp); extern int xfs_buf_submit_wait(struct xfs_buf *bp); extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *, xfs_buf_rw_t); #define xfs_buf_zero(bp, off, len) \ xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO) /* Buffer Utility Routines */ extern void *xfs_buf_offset(struct xfs_buf *, size_t); extern void xfs_buf_stale(struct xfs_buf *bp); /* Delayed Write Buffer Routines */ extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *); extern int xfs_buf_delwri_submit(struct list_head *); extern int xfs_buf_delwri_submit_nowait(struct list_head *); /* Buffer Daemon Setup Routines */ extern int xfs_buf_init(void); extern void xfs_buf_terminate(void); /* * These macros use the IO block map rather than b_bn. b_bn is now really * just for the buffer cache index for cached buffers. As IO does not use b_bn * anymore, uncached buffers do not use b_bn at all and hence must modify the IO * map directly. Uncached buffers are not allowed to be discontiguous, so this * is safe to do. * * In future, uncached buffers will pass the block number directly to the io * request function and hence these macros will go away at that point. */ #define XFS_BUF_ADDR(bp) ((bp)->b_maps[0].bm_bn) #define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_maps[0].bm_bn = (xfs_daddr_t)(bno))
static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref) { atomic_set(&bp->b_lru_ref, lru_ref); }

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static inline int xfs_buf_ispinned(struct xfs_buf *bp) { return atomic_read(&bp->b_pin_count); }

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static inline void xfs_buf_relse(xfs_buf_t *bp) { xfs_buf_unlock(bp); xfs_buf_rele(bp); }

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static inline int xfs_buf_verify_cksum(struct xfs_buf *bp, unsigned long cksum_offset) { return xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length), cksum_offset); }

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static inline void xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset) { xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length), cksum_offset); }

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/* * Handling of buftargs. */ extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *, struct block_device *); extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *); extern void xfs_wait_buftarg(xfs_buftarg_t *); extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int); #define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev) #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev) #endif /* __XFS_BUF_H__ */

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dave chinnerdave chinner62245.24%3037.97%
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eric sandeeneric sandeen876.33%78.86%
nathan scottnathan scott715.16%810.13%
brian fosterbrian foster221.60%33.80%
chandra seetharamanchandra seetharaman181.31%11.27%
david chinnerdavid chinner141.02%45.06%
carlos maiolinocarlos maiolino141.02%33.80%
mark tinguelymark tinguely30.22%11.27%
lucas stachlucas stach30.22%11.27%
matthew wilcoxmatthew wilcox30.22%11.27%
Total1375100.00%79100.00%
Directory: fs/xfs
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