/* $NetBSD: buf.h,v 1.136 2026/03/31 09:08:05 yamt Exp $ */ /*- * Copyright (c) 1999, 2000, 2007, 2008 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, * NASA Ames Research Center, and by Andrew Doran. * * 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. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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. */ /* * 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. * 3. 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 */ #ifndef _SYS_BUF_H_ #define _SYS_BUF_H_ #include <sys/pool.h> #include <sys/queue.h> #include <sys/mutex.h> #include <sys/condvar.h> #include <sys/rbtree.h> #if defined(_KERNEL) #include <sys/workqueue.h> #endif /* defined(_KERNEL) */ struct buf; struct mount; struct vnode; struct kauth_cred; #define NOLIST ((struct buf *)0x87654321) extern kmutex_t bufcache_lock; extern kmutex_t buffer_lock; #if defined(_KERNEL) extern void (*biodone_vfs)(buf_t *); #endif /* * The buffer header describes an I/O operation in the kernel. * * Field markings and the corresponding locks: * * b thread of execution that holds BC_BUSY, does not correspond * directly to any particular LWP * c bufcache_lock * o b_objlock * * For buffers associated with a vnode, b_objlock points to vp->v_interlock. * If not associated with a vnode, it points to the generic buffer_lock. */ /* required for the conditional union member below to be ~safe */ #if defined(_KERNEL) __CTASSERT(sizeof(struct work) <= sizeof(TAILQ_ENTRY(buf))); #endif struct buf { union { TAILQ_ENTRY(buf) u_actq; rb_node_t u_rbnode; #if defined(_KERNEL) /* u_work is smaller than u_actq */ struct work u_work; #endif } b_u; /* b: device driver queue */ #define b_actq b_u.u_actq #define b_work b_u.u_work void (*b_iodone)(struct buf *);/* b: call when done */ int b_error; /* b: errno value. */ int b_resid; /* b: remaining I/O. */ u_int b_flags; /* b: B_* flags */ int b_prio; /* b: priority for queue */ int b_bufsize; /* b: allocated size */ int b_bcount; /* b: valid bytes in buffer */ dev_t b_dev; /* b: associated device */ void *b_data; /* b: fs private data */ daddr_t b_blkno; /* b: physical block number (partition relative) */ daddr_t b_rawblkno; /* b: raw physical block number (volume relative) */ struct proc *b_proc; /* b: proc if BB_PHYS */ void *b_saveaddr; /* b: saved b_data for physio */ struct cpu_info *b_ci; /* b: originating CPU */ /* * b: private data for owner. * - buffer cache buffers are owned by corresponding filesystem. * - non-buffer cache buffers are owned by subsystem which * allocated them. (filesystem, disk driver, etc) */ void *b_private; off_t b_dcookie; /* NFS: Offset cookie if dir block */ kcondvar_t b_busy; /* c: threads waiting on buf */ void *b_private2; /* : private data for owner */ LIST_ENTRY(buf) b_hash; /* c: hash chain */ LIST_ENTRY(buf) b_vnbufs; /* c: associated vnode */ TAILQ_ENTRY(buf) b_freelist; /* c: position if not active */ TAILQ_ENTRY(buf) b_wapbllist; /* c: transaction buffer list */ daddr_t b_lblkno; /* c: logical block number */ int b_freelistindex;/* c: free list index (BQ_) */ u_int b_cflags; /* c: BC_* flags */ struct vnode *b_vp; /* c: file vnode */ kcondvar_t b_done; /* o: waiting on completion */ u_int b_oflags; /* o: BO_* flags */ kmutex_t *b_objlock; /* o: completion lock */ }; /* * For portability with historic industry practice, the cylinder number has * to be maintained in the `b_resid' field. */ #define b_cylinder b_resid /* Cylinder number for disksort(). */ /* * These flags are kept in b_cflags (owned by buffer cache). */ #define BC_AGE 0x00000001 /* Move to age queue when I/O done. */ #define BC_BUSY 0x00000010 /* I/O in progress. */ #define BC_INVAL 0x00002000 /* Does not contain valid info. */ #define BC_NOCACHE 0x00008000 /* Do not cache block after use. */ #define BC_WANTED 0x00800000 /* Process wants this buffer. */ #define BC_VFLUSH 0x04000000 /* Buffer is being synced. */ /* * These flags are kept in b_oflags (owned by associated object). */ #define BO_DELWRI 0x00000080 /* Delay I/O until buffer reused. */ #define BO_DONE 0x00000200 /* I/O completed. */ /* * These flags are kept in b_flags (owned by buffer holder). */ #define B_WRITE 0x00000000 /* Write buffer (pseudo flag). */ #define B_ASYNC 0x00000004 /* Start I/O, do not wait. */ #define B_COWDONE 0x00000400 /* Copy-on-write already done. */ #define B_GATHERED 0x00001000 /* LFS: already in a segment. */ #define B_LOCKED 0x00004000 /* Locked in core (not reusable). */ #define B_PHYS 0x00040000 /* I/O to user memory. */ #define B_RAW 0x00080000 /* Set by physio for raw transfers. */ #define B_READ 0x00100000 /* Read buffer. */ #define B_DEVPRIVATE 0x02000000 /* Device driver private flag. */ #define B_MEDIA_FUA 0x08000000 /* Set Force Unit Access for media. */ #define B_MEDIA_DPO 0x10000000 /* Set Disable Page Out for media. */ #define BUF_FLAGBITS \ "\20\1AGE\3ASYNC\4BAD\5BUSY\10DELWRI" \ "\12DONE\13COWDONE\15GATHERED\16INVAL\17LOCKED\20NOCACHE" \ "\23PHYS\24RAW\25READ\32DEVPRIVATE\33VFLUSH\34MEDIA_FUA\35MEDIA_DPO" /* Avoid weird code due to B_WRITE being a "pseudo flag" */ #define BUF_ISREAD(bp) (((bp)->b_flags & B_READ) == B_READ) #define BUF_ISWRITE(bp) (((bp)->b_flags & B_READ) == B_WRITE) /* Media flags, to be passed for nested I/O */ #define B_MEDIA_FLAGS (B_MEDIA_FUA|B_MEDIA_DPO) /* * 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. */ }; /* * Zero out the buffer's data area. */ #define clrbuf(bp) \ do { \ memset((bp)->b_data, 0, (u_int)(bp)->b_bcount); \ (bp)->b_resid = 0; \ } while (0) /* Flags to low-level allocation routines. */ #define B_CLRBUF 0x01 /* Request allocated buffer be cleared. */ #define B_SYNC 0x02 /* Do all allocations synchronously. */ #define B_METAONLY 0x04 /* Return indirect block buffer. */ #define B_CONTIG 0x08 /* Allocate file contiguously. */ /* Flags to bread() and breadn(). */ #define B_MODIFY 0x01 /* Hint: caller might modify buffer */ #ifdef _KERNEL #define BIO_GETPRIO(bp) ((bp)->b_prio) #define BIO_SETPRIO(bp, prio) (bp)->b_prio = (prio) #define BIO_COPYPRIO(bp1, bp2) BIO_SETPRIO(bp1, BIO_GETPRIO(bp2)) #define BPRIO_NPRIO 3 #define BPRIO_TIMECRITICAL 2 #define BPRIO_TIMELIMITED 1 #define BPRIO_TIMENONCRITICAL 0 #define BPRIO_DEFAULT BPRIO_TIMELIMITED __BEGIN_DECLS /* * bufferio(9) ops */ void biodone(buf_t *); int biowait(buf_t *); buf_t *getiobuf(struct vnode *, bool); void putiobuf(buf_t *); void nestiobuf_setup(buf_t *, buf_t *, int, size_t); void nestiobuf_done(buf_t *, int, int); void nestiobuf_iodone(buf_t *); int physio(void (*)(buf_t *), buf_t *, dev_t, int, void (*)(buf_t *), struct uio *); /* * buffercache(9) ops */ int bread(struct vnode *, daddr_t, int, int, buf_t **); int breadn(struct vnode *, daddr_t, int, daddr_t *, int *, int, int, buf_t **); int bwrite(buf_t *); void bawrite(buf_t *); void bdwrite(buf_t *); buf_t *getblk(struct vnode *, daddr_t, int, int, int); buf_t *geteblk(int); buf_t *incore(struct vnode *, daddr_t); int allocbuf(buf_t *, int, int); void brelsel(buf_t *, int); void brelse(buf_t *, int); void binvalbuf(struct vnode *, daddr_t); /* * So-far indeterminate ops that might belong to either * bufferio(9) or buffercache(9). */ void bremfree(buf_t *); void bufinit(void); void bufinit2(void); void minphys(buf_t *); void brelvp(buf_t *); void reassignbuf(buf_t *, struct vnode *); void bgetvp(struct vnode *, buf_t *); u_long buf_memcalc(void); int buf_drain(int); int buf_setvalimit(vsize_t); #if defined(DDB) || defined(DEBUGPRINT) void vfs_buf_print(buf_t *, int, void (*)(const char *, ...) __printflike(1, 2)); #endif void buf_init(buf_t *); void buf_destroy(buf_t *); int bbusy(buf_t *, bool, int, kmutex_t *); u_int buf_nbuf(void); void biohist_init(void); __END_DECLS #endif /* _KERNEL */ #endif /* !_SYS_BUF_H_ */
