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/*-
* Copyright (c) 1982, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)buf.h 8.9 (Berkeley) 3/30/95
* $FreeBSD: release/9.1.0/sys/sys/buf.h 236796 2012-06-09 08:13:57Z kib $
*/
#ifndef _SYS_BUF_H_
#define _SYS_BUF_H_
#include <sys/bufobj.h>
#include <sys/queue.h>
#include <sys/lock.h>
#include <sys/lockmgr.h>
struct bio;
struct buf;
struct bufobj;
struct mount;
struct vnode;
struct uio;
/*
* To avoid including <ufs/ffs/softdep.h>
*/
LIST_HEAD(workhead, worklist);
/*
* These are currently used only by the soft dependency code, hence
* are stored once in a global variable. If other subsystems wanted
* to use these hooks, a pointer to a set of bio_ops could be added
* to each buffer.
*/
extern struct bio_ops {
void (*io_start)(struct buf *);
void (*io_complete)(struct buf *);
void (*io_deallocate)(struct buf *);
int (*io_countdeps)(struct buf *, int);
} bioops;
struct vm_object;
typedef unsigned char b_xflags_t;
/*
* The buffer header describes an I/O operation in the kernel.
*
* NOTES:
* b_bufsize, b_bcount. b_bufsize is the allocation size of the
* buffer, either DEV_BSIZE or PAGE_SIZE aligned. b_bcount is the
* originally requested buffer size and can serve as a bounds check
* against EOF. For most, but not all uses, b_bcount == b_bufsize.
*
* b_dirtyoff, b_dirtyend. Buffers support piecemeal, unaligned
* ranges of dirty data that need to be written to backing store.
* The range is typically clipped at b_bcount ( not b_bufsize ).
*
* b_resid. Number of bytes remaining in I/O. After an I/O operation
* completes, b_resid is usually 0 indicating 100% success.
*
* All fields are protected by the buffer lock except those marked:
* V - Protected by owning bufobj lock
* Q - Protected by the buf queue lock
* D - Protected by an dependency implementation specific lock
*/
struct buf {
struct bufobj *b_bufobj;
long b_bcount;
void *b_caller1;
caddr_t b_data;
int b_error;
uint8_t b_iocmd;
uint8_t b_ioflags;
off_t b_iooffset;
long b_resid;
void (*b_iodone)(struct buf *);
daddr_t b_blkno; /* Underlying physical block number. */
off_t b_offset; /* Offset into file. */
TAILQ_ENTRY(buf) b_bobufs; /* (V) Buffer's associated vnode. */
struct buf *b_left; /* (V) splay tree link */
struct buf *b_right; /* (V) splay tree link */
uint32_t b_vflags; /* (V) BV_* flags */
TAILQ_ENTRY(buf) b_freelist; /* (Q) Free list position inactive. */
unsigned short b_qindex; /* (Q) buffer queue index */
uint32_t b_flags; /* B_* flags. */
b_xflags_t b_xflags; /* extra flags */
struct lock b_lock; /* Buffer lock */
long b_bufsize; /* Allocated buffer size. */
long b_runningbufspace; /* when I/O is running, pipelining */
caddr_t b_kvabase; /* base kva for buffer */
int b_kvasize; /* size of kva for buffer */
daddr_t b_lblkno; /* Logical block number. */
struct vnode *b_vp; /* Device vnode. */
int b_dirtyoff; /* Offset in buffer of dirty region. */
int b_dirtyend; /* Offset of end of dirty region. */
struct ucred *b_rcred; /* Read credentials reference. */
struct ucred *b_wcred; /* Write credentials reference. */
void *b_saveaddr; /* Original b_addr for physio. */
union pager_info {
int pg_reqpage;
} b_pager;
union cluster_info {
TAILQ_HEAD(cluster_list_head, buf) cluster_head;
TAILQ_ENTRY(buf) cluster_entry;
} b_cluster;
struct vm_page *b_pages[btoc(MAXPHYS)];
int b_npages;
struct workhead b_dep; /* (D) List of filesystem dependencies. */
void *b_fsprivate1;
void *b_fsprivate2;
void *b_fsprivate3;
int b_pin_count;
};
#define b_object b_bufobj->bo_object
/*
* These flags are kept in b_flags.
*
* Notes:
*
* B_ASYNC VOP calls on bp's are usually async whether or not
* B_ASYNC is set, but some subsystems, such as NFS, like
* to know what is best for the caller so they can
* optimize the I/O.
*
* B_PAGING Indicates that bp is being used by the paging system or
* some paging system and that the bp is not linked into
* the b_vp's clean/dirty linked lists or ref counts.
* Buffer vp reassignments are illegal in this case.
*
* B_CACHE This may only be set if the buffer is entirely valid.
* The situation where B_DELWRI is set and B_CACHE is
* clear MUST be committed to disk by getblk() so
* B_DELWRI can also be cleared. See the comments for
* getblk() in kern/vfs_bio.c. If B_CACHE is clear,
* the caller is expected to clear BIO_ERROR and B_INVAL,
* set BIO_READ, and initiate an I/O.
*
* The 'entire buffer' is defined to be the range from
* 0 through b_bcount.
*
* B_MALLOC Request that the buffer be allocated from the malloc
* pool, DEV_BSIZE aligned instead of PAGE_SIZE aligned.
*
* B_CLUSTEROK This flag is typically set for B_DELWRI buffers
* by filesystems that allow clustering when the buffer
* is fully dirty and indicates that it may be clustered
* with other adjacent dirty buffers. Note the clustering
* may not be used with the stage 1 data write under NFS
* but may be used for the commit rpc portion.
*
* B_VMIO Indicates that the buffer is tied into an VM object.
* The buffer's data is always PAGE_SIZE aligned even
* if b_bufsize and b_bcount are not. ( b_bufsize is
* always at least DEV_BSIZE aligned, though ).
*
* B_DIRECT Hint that we should attempt to completely free
* the pages underlying the buffer. B_DIRECT is
* sticky until the buffer is released and typically
* only has an effect when B_RELBUF is also set.
*
*/
#define B_AGE 0x00000001 /* Move to age queue when I/O done. */
#define B_NEEDCOMMIT 0x00000002 /* Append-write in progress. */
#define B_ASYNC 0x00000004 /* Start I/O, do not wait. */
#define B_DIRECT 0x00000008 /* direct I/O flag (pls free vmio) */
#define B_DEFERRED 0x00000010 /* Skipped over for cleaning */
#define B_CACHE 0x00000020 /* Bread found us in the cache. */
#define B_VALIDSUSPWRT 0x00000040 /* Valid write during suspension. */
#define B_DELWRI 0x00000080 /* Delay I/O until buffer reused. */
#define B_PERSISTENT 0x00000100 /* Perm. ref'ed while EXT2FS mounted. */
#define B_DONE 0x00000200 /* I/O completed. */
#define B_EINTR 0x00000400 /* I/O was interrupted */
#define B_00000800 0x00000800 /* Available flag. */
#define B_00001000 0x00001000 /* Available flag. */
#define B_INVAL 0x00002000 /* Does not contain valid info. */
#define B_00004000 0x00004000 /* Available flag. */
#define B_NOCACHE 0x00008000 /* Do not cache block after use. */
#define B_MALLOC 0x00010000 /* malloced b_data */
#define B_CLUSTEROK 0x00020000 /* Pagein op, so swap() can count it. */
#define B_000400000 0x00040000 /* Available flag. */
#define B_000800000 0x00080000 /* Available flag. */
#define B_00100000 0x00100000 /* Available flag. */
#define B_DIRTY 0x00200000 /* Needs writing later (in EXT2FS). */
#define B_RELBUF 0x00400000 /* Release VMIO buffer. */
#define B_00800000 0x00800000 /* Available flag. */
#define B_NOCOPY 0x01000000 /* Don't copy-on-write this buf. */
#define B_NEEDSGIANT 0x02000000 /* Buffer's vnode needs giant. */
#define B_PAGING 0x04000000 /* volatile paging I/O -- bypass VMIO */
#define B_MANAGED 0x08000000 /* Managed by FS. */
#define B_RAM 0x10000000 /* Read ahead mark (flag) */
#define B_VMIO 0x20000000 /* VMIO flag */
#define B_CLUSTER 0x40000000 /* pagein op, so swap() can count it */
#define B_REMFREE 0x80000000 /* Delayed bremfree */
#define PRINT_BUF_FLAGS "\20\40remfree\37cluster\36vmio\35ram\34managed" \
"\33paging\32needsgiant\31nocopy\30b23\27relbuf\26dirty\25b20" \
"\24b19\23b18\22clusterok\21malloc\20nocache\17b14\16inval" \
"\15b12\14b11\13eintr\12done\11persist\10delwri\7validsuspwrt" \
"\6cache\5deferred\4direct\3async\2needcommit\1age"
/*
* These flags are kept in b_xflags.
*/
#define BX_VNDIRTY 0x00000001 /* On vnode dirty list */
#define BX_VNCLEAN 0x00000002 /* On vnode clean list */
#define BX_BKGRDWRITE 0x00000010 /* Do writes in background */
#define BX_BKGRDMARKER 0x00000020 /* Mark buffer for splay tree */
#define BX_ALTDATA 0x00000040 /* Holds extended data */
#define PRINT_BUF_XFLAGS "\20\7altdata\6bkgrdmarker\5bkgrdwrite\2clean\1dirty"
#define NOOFFSET (-1LL) /* No buffer offset calculated yet */
/*
* These flags are kept in b_vflags.
*/
#define BV_SCANNED 0x00000001 /* VOP_FSYNC funcs mark written bufs */
#define BV_BKGRDINPROG 0x00000002 /* Background write in progress */
#define BV_BKGRDWAIT 0x00000004 /* Background write waiting */
#define BV_INFREECNT 0x80000000 /* buf is counted in numfreebufs */
#define PRINT_BUF_VFLAGS "\20\40infreecnt\3bkgrdwait\2bkgrdinprog\1scanned"
#ifdef _KERNEL
/*
* Buffer locking
*/
extern const char *buf_wmesg; /* Default buffer lock message */
#define BUF_WMESG "bufwait"
#include <sys/proc.h> /* XXX for curthread */
#include <sys/mutex.h>
/*
* Initialize a lock.
*/
#define BUF_LOCKINIT(bp) \
lockinit(&(bp)->b_lock, PRIBIO + 4, buf_wmesg, 0, 0)
/*
*
* Get a lock sleeping non-interruptably until it becomes available.
*/
#define BUF_LOCK(bp, locktype, interlock) \
_lockmgr_args(&(bp)->b_lock, (locktype), (interlock), \
LK_WMESG_DEFAULT, LK_PRIO_DEFAULT, LK_TIMO_DEFAULT, \
LOCK_FILE, LOCK_LINE)
/*
* Get a lock sleeping with specified interruptably and timeout.
*/
#define BUF_TIMELOCK(bp, locktype, interlock, wmesg, catch, timo) \
_lockmgr_args(&(bp)->b_lock, (locktype) | LK_TIMELOCK, \
(interlock), (wmesg), (PRIBIO + 4) | (catch), (timo), \
LOCK_FILE, LOCK_LINE)
/*
* Release a lock. Only the acquiring process may free the lock unless
* it has been handed off to biodone.
*/
#define BUF_UNLOCK(bp) do { \
KASSERT(((bp)->b_flags & B_REMFREE) == 0, \
("BUF_UNLOCK %p while B_REMFREE is still set.", (bp))); \
\
(void)_lockmgr_args(&(bp)->b_lock, LK_RELEASE, NULL, \
LK_WMESG_DEFAULT, LK_PRIO_DEFAULT, LK_TIMO_DEFAULT, \
LOCK_FILE, LOCK_LINE); \
} while (0)
/*
* Check if a buffer lock is recursed.
*/
#define BUF_LOCKRECURSED(bp) \
lockmgr_recursed(&(bp)->b_lock)
/*
* Check if a buffer lock is currently held.
*/
#define BUF_ISLOCKED(bp) \
lockstatus(&(bp)->b_lock)
/*
* Free a buffer lock.
*/
#define BUF_LOCKFREE(bp) \
lockdestroy(&(bp)->b_lock)
/*
* Print informations on a buffer lock.
*/
#define BUF_LOCKPRINTINFO(bp) \
lockmgr_printinfo(&(bp)->b_lock)
/*
* Buffer lock assertions.
*/
#if defined(INVARIANTS) && defined(INVARIANT_SUPPORT)
#define BUF_ASSERT_LOCKED(bp) \
_lockmgr_assert(&(bp)->b_lock, KA_LOCKED, LOCK_FILE, LOCK_LINE)
#define BUF_ASSERT_SLOCKED(bp) \
_lockmgr_assert(&(bp)->b_lock, KA_SLOCKED, LOCK_FILE, LOCK_LINE)
#define BUF_ASSERT_XLOCKED(bp) \
_lockmgr_assert(&(bp)->b_lock, KA_XLOCKED, LOCK_FILE, LOCK_LINE)
#define BUF_ASSERT_UNLOCKED(bp) \
_lockmgr_assert(&(bp)->b_lock, KA_UNLOCKED, LOCK_FILE, LOCK_LINE)
#define BUF_ASSERT_HELD(bp)
#define BUF_ASSERT_UNHELD(bp)
#else
#define BUF_ASSERT_LOCKED(bp)
#define BUF_ASSERT_SLOCKED(bp)
#define BUF_ASSERT_XLOCKED(bp)
#define BUF_ASSERT_UNLOCKED(bp)
#define BUF_ASSERT_HELD(bp)
#define BUF_ASSERT_UNHELD(bp)
#endif
#ifdef _SYS_PROC_H_ /* Avoid #include <sys/proc.h> pollution */
/*
* When initiating asynchronous I/O, change ownership of the lock to the
* kernel. Once done, the lock may legally released by biodone. The
* original owning process can no longer acquire it recursively, but must
* wait until the I/O is completed and the lock has been freed by biodone.
*/
#define BUF_KERNPROC(bp) \
_lockmgr_disown(&(bp)->b_lock, LOCK_FILE, LOCK_LINE)
#endif
/*
* Find out if the lock has waiters or not.
*/
#define BUF_LOCKWAITERS(bp) \
lockmgr_waiters(&(bp)->b_lock)
#endif /* _KERNEL */
struct buf_queue_head {
TAILQ_HEAD(buf_queue, buf) queue;
daddr_t last_pblkno;
struct buf *insert_point;
struct buf *switch_point;
};
/*
* This structure describes a clustered I/O. It is stored in the b_saveaddr
* field of the buffer on which I/O is done. At I/O completion, cluster
* callback uses the structure to parcel I/O's to individual buffers, and
* then free's this structure.
*/
struct cluster_save {
long bs_bcount; /* Saved b_bcount. */
long bs_bufsize; /* Saved b_bufsize. */
void *bs_saveaddr; /* Saved b_addr. */
int bs_nchildren; /* Number of associated buffers. */
struct buf **bs_children; /* List of associated buffers. */
};
#ifdef _KERNEL
static __inline int
bwrite(struct buf *bp)
{
KASSERT(bp->b_bufobj != NULL, ("bwrite: no bufobj bp=%p", bp));
KASSERT(bp->b_bufobj->bo_ops != NULL, ("bwrite: no bo_ops bp=%p", bp));
KASSERT(bp->b_bufobj->bo_ops->bop_write != NULL,
("bwrite: no bop_write bp=%p", bp));
return (BO_WRITE(bp->b_bufobj, bp));
}
static __inline void
bstrategy(struct buf *bp)
{
KASSERT(bp->b_bufobj != NULL, ("bstrategy: no bufobj bp=%p", bp));
KASSERT(bp->b_bufobj->bo_ops != NULL,
("bstrategy: no bo_ops bp=%p", bp));
KASSERT(bp->b_bufobj->bo_ops->bop_strategy != NULL,
("bstrategy: no bop_strategy bp=%p", bp));
BO_STRATEGY(bp->b_bufobj, bp);
}
static __inline void
buf_start(struct buf *bp)
{
if (bioops.io_start)
(*bioops.io_start)(bp);
}
static __inline void
buf_complete(struct buf *bp)
{
if (bioops.io_complete)
(*bioops.io_complete)(bp);
}
static __inline void
buf_deallocate(struct buf *bp)
{
if (bioops.io_deallocate)
(*bioops.io_deallocate)(bp);
BUF_LOCKFREE(bp);
}
static __inline int
buf_countdeps(struct buf *bp, int i)
{
if (bioops.io_countdeps)
return ((*bioops.io_countdeps)(bp, i));
else
return (0);
}
#endif /* _KERNEL */
/*
* Zero out the buffer's data area.
*/
#define clrbuf(bp) { \
bzero((bp)->b_data, (u_int)(bp)->b_bcount); \
(bp)->b_resid = 0; \
}
/*
* Flags for getblk's last parameter.
*/
#define GB_LOCK_NOWAIT 0x0001 /* Fail if we block on a buf lock. */
#define GB_NOCREAT 0x0002 /* Don't create a buf if not found. */
#define GB_NOWAIT_BD 0x0004 /* Do not wait for bufdaemon */
#ifdef _KERNEL
extern int nbuf; /* The number of buffer headers */
extern long maxswzone; /* Max KVA for swap structures */
extern long maxbcache; /* Max KVA for buffer cache */
extern long runningbufspace;
extern long hibufspace;
extern int dirtybufthresh;
extern int bdwriteskip;
extern int dirtybufferflushes;
extern int altbufferflushes;
extern int buf_maxio; /* nominal maximum I/O for buffer */
extern struct buf *buf; /* The buffer headers. */
extern char *buffers; /* The buffer contents. */
extern int bufpages; /* Number of memory pages in the buffer pool. */
extern struct buf *swbuf; /* Swap I/O buffer headers. */
extern int nswbuf; /* Number of swap I/O buffer headers. */
extern int cluster_pbuf_freecnt; /* Number of pbufs for clusters */
extern int vnode_pbuf_freecnt; /* Number of pbufs for vnode pager */
void runningbufwakeup(struct buf *);
void waitrunningbufspace(void);
caddr_t kern_vfs_bio_buffer_alloc(caddr_t v, long physmem_est);
void bufinit(void);
void bwillwrite(void);
int buf_dirty_count_severe(void);
void bremfree(struct buf *);
void bremfreef(struct buf *); /* XXX Force bremfree, only for nfs. */
int bread(struct vnode *, daddr_t, int, struct ucred *, struct buf **);
void breada(struct vnode *, daddr_t *, int *, int, struct ucred *);
int breadn(struct vnode *, daddr_t, int, daddr_t *, int *, int,
struct ucred *, struct buf **);
int breadn_flags(struct vnode *, daddr_t, int, daddr_t *, int *, int,
struct ucred *, int, struct buf **);
void bdwrite(struct buf *);
void bawrite(struct buf *);
void bdirty(struct buf *);
void bundirty(struct buf *);
void bufstrategy(struct bufobj *, struct buf *);
void brelse(struct buf *);
void bqrelse(struct buf *);
int vfs_bio_awrite(struct buf *);
struct buf * getpbuf(int *);
struct buf *incore(struct bufobj *, daddr_t);
struct buf *gbincore(struct bufobj *, daddr_t);
struct buf *getblk(struct vnode *, daddr_t, int, int, int, int);
struct buf *geteblk(int, int);
int bufwait(struct buf *);
int bufwrite(struct buf *);
void bufdone(struct buf *);
void bufdone_finish(struct buf *);
void bd_speedup(void);
int cluster_read(struct vnode *, u_quad_t, daddr_t, long,
struct ucred *, long, int, struct buf **);
int cluster_wbuild(struct vnode *, long, daddr_t, int);
void cluster_write(struct vnode *, struct buf *, u_quad_t, int);
void vfs_bio_set_valid(struct buf *, int base, int size);
void vfs_bio_clrbuf(struct buf *);
void vfs_busy_pages(struct buf *, int clear_modify);
void vfs_unbusy_pages(struct buf *);
int vmapbuf(struct buf *);
void vunmapbuf(struct buf *);
void relpbuf(struct buf *, int *);
void brelvp(struct buf *);
void bgetvp(struct vnode *, struct buf *);
void pbgetbo(struct bufobj *bo, struct buf *bp);
void pbgetvp(struct vnode *, struct buf *);
void pbrelbo(struct buf *);
void pbrelvp(struct buf *);
int allocbuf(struct buf *bp, int size);
void reassignbuf(struct buf *);
struct buf *trypbuf(int *);
void bwait(struct buf *, u_char, const char *);
void bdone(struct buf *);
void bpin(struct buf *);
void bunpin(struct buf *);
void bunpin_wait(struct buf *);
#endif /* _KERNEL */
#endif /* !_SYS_BUF_H_ */