// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#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/uio.h>
#include <linux/list_lru.h>
/*
* Base types
*/
#define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))
#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 << 7) /* async writes have failed on this buffer */
/* 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 */
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_TRYLOCK, "TRYLOCK" }, /* should never be set */\
{ XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\
{ _XBF_PAGES, "PAGES" }, \
{ _XBF_KMEM, "KMEM" }, \
{ _XBF_DELWRI_Q, "DELWRI_Q" }
/*
* Internal state flags.
*/
#define XFS_BSTATE_DISPOSE (1 << 0) /* buffer being discarded */
#define XFS_BSTATE_IN_FLIGHT (1 << 1) /* I/O in flight */
/*
* 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 dax_device *bt_daxdev;
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;
union {
__be32 magic[2]; /* v4 and v5 on disk magic values */
__be16 magic16[2]; /* v4 and v5 on disk magic values */
};
void (*verify_read)(struct xfs_buf *);
void (*verify_write)(struct xfs_buf *);
xfs_failaddr_t (*verify_struct)(struct xfs_buf *bp);
};
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;
xfs_buf_iodone_t b_iodone; /* I/O completion function */
struct completion b_iowait; /* queue for I/O waiters */
void *b_log_item;
struct list_head b_li_list; /* Log items list head */
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;
} xfs_buf_t;
/* Finding and Reading Buffers */
struct xfs_buf *xfs_buf_incore(struct xfs_buftarg *target,
xfs_daddr_t blkno, size_t numblks,
xfs_buf_flags_t flags);
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)
{
DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
return xfs_buf_get_map(target, &map, 1, 0);
}
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);
}
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);
}
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(struct xfs_buf *bp, int error,
xfs_failaddr_t failaddr);
#define xfs_buf_ioerror(bp, err) __xfs_buf_ioerror((bp), (err), __this_address)
extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func);
extern int __xfs_buf_submit(struct xfs_buf *bp, bool);
static inline int xfs_buf_submit(struct xfs_buf *bp)
{
bool wait = bp->b_flags & XBF_ASYNC ? false : true;
return __xfs_buf_submit(bp, wait);
}
void xfs_buf_zero(struct xfs_buf *bp, size_t boff, size_t bsize);
/* 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 void xfs_buf_delwri_cancel(struct list_head *);
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 *);
extern int xfs_buf_delwri_pushbuf(struct xfs_buf *, 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))
void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref);
/*
* If the buffer is already on the LRU, do nothing. Otherwise set the buffer
* up with a reference count of 0 so it will be tossed from the cache when
* released.
*/
static inline void xfs_buf_oneshot(struct xfs_buf *bp)
{
if (!list_empty(&bp->b_lru) || atomic_read(&bp->b_lru_ref) > 1)
return;
atomic_set(&bp->b_lru_ref, 0);
}
static inline int xfs_buf_ispinned(struct xfs_buf *bp)
{
return atomic_read(&bp->b_pin_count);
}
static inline void xfs_buf_relse(xfs_buf_t *bp)
{
xfs_buf_unlock(bp);
xfs_buf_rele(bp);
}
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);
}
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);
}
/*
* Handling of buftargs.
*/
extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *,
struct block_device *, struct dax_device *);
extern void xfs_free_buftarg(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)
int xfs_buf_reverify(struct xfs_buf *bp, const struct xfs_buf_ops *ops);
bool xfs_verify_magic(struct xfs_buf *bp, __be32 dmagic);
bool xfs_verify_magic16(struct xfs_buf *bp, __be16 dmagic);
#endif /* __XFS_BUF_H__ */
