1 /* $NetBSD: buf.h,v 1.119 2012/02/17 08:45:11 yamt Exp $ */ 2 3 /*- 4 * Copyright (c) 1999, 2000, 2007, 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 9 * NASA Ames Research Center, and by Andrew Doran. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 /* 34 * Copyright (c) 1982, 1986, 1989, 1993 35 * The Regents of the University of California. All rights reserved. 36 * (c) UNIX System Laboratories, Inc. 37 * All or some portions of this file are derived from material licensed 38 * to the University of California by American Telephone and Telegraph 39 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 40 * the permission of UNIX System Laboratories, Inc. 41 * 42 * Redistribution and use in source and binary forms, with or without 43 * modification, are permitted provided that the following conditions 44 * are met: 45 * 1. Redistributions of source code must retain the above copyright 46 * notice, this list of conditions and the following disclaimer. 47 * 2. Redistributions in binary form must reproduce the above copyright 48 * notice, this list of conditions and the following disclaimer in the 49 * documentation and/or other materials provided with the distribution. 50 * 3. Neither the name of the University nor the names of its contributors 51 * may be used to endorse or promote products derived from this software 52 * without specific prior written permission. 53 * 54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 64 * SUCH DAMAGE. 65 * 66 * @(#)buf.h 8.9 (Berkeley) 3/30/95 67 */ 68 69 #ifndef _SYS_BUF_H_ 70 #define _SYS_BUF_H_ 71 72 #include <sys/pool.h> 73 #include <sys/queue.h> 74 #include <sys/mutex.h> 75 #include <sys/condvar.h> 76 #include <sys/rbtree.h> 77 #if defined(_KERNEL) 78 #include <sys/workqueue.h> 79 #endif /* defined(_KERNEL) */ 80 81 struct buf; 82 struct mount; 83 struct vnode; 84 struct kauth_cred; 85 86 #define NOLIST ((struct buf *)0x87654321) 87 88 extern kmutex_t bufcache_lock; 89 extern kmutex_t buffer_lock; 90 91 /* 92 * The buffer header describes an I/O operation in the kernel. 93 * 94 * Field markings and the corresponding locks: 95 * 96 * b thread of execution that holds BC_BUSY, does not correspond 97 * directly to any particular LWP 98 * c bufcache_lock 99 * o b_objlock 100 * 101 * For buffers associated with a vnode, b_objlock points to vp->v_interlock. 102 * If not associated with a vnode, it points to the generic buffer_lock. 103 */ 104 struct buf { 105 union { 106 TAILQ_ENTRY(buf) u_actq; 107 rb_node_t u_rbnode; 108 #if defined(_KERNEL) /* u_work is smaller than u_actq. XXX */ 109 struct work u_work; 110 #endif /* defined(_KERNEL) */ 111 } b_u; /* b: device driver queue */ 112 #define b_actq b_u.u_actq 113 #define b_work b_u.u_work 114 void (*b_iodone)(struct buf *);/* b: call when done */ 115 int b_error; /* b: errno value. */ 116 int b_resid; /* b: remaining I/O. */ 117 u_int b_flags; /* b: B_* flags */ 118 int b_prio; /* b: priority for queue */ 119 int b_bufsize; /* b: allocated size */ 120 int b_bcount; /* b: valid bytes in buffer */ 121 dev_t b_dev; /* b: associated device */ 122 void *b_data; /* b: fs private data */ 123 daddr_t b_blkno; /* b: physical block number 124 (partition relative) */ 125 daddr_t b_rawblkno; /* b: raw physical block number 126 (volume relative) */ 127 struct proc *b_proc; /* b: proc if BB_PHYS */ 128 void *b_saveaddr; /* b: saved b_data for physio */ 129 130 /* 131 * b: private data for owner. 132 * - buffer cache buffers are owned by corresponding filesystem. 133 * - non-buffer cache buffers are owned by subsystem which 134 * allocated them. (filesystem, disk driver, etc) 135 */ 136 void *b_private; 137 off_t b_dcookie; /* NFS: Offset cookie if dir block */ 138 139 kcondvar_t b_busy; /* c: threads waiting on buf */ 140 u_int b_refcnt; /* c: refcount for b_busy */ 141 void *b_unused; /* : unused */ 142 LIST_ENTRY(buf) b_hash; /* c: hash chain */ 143 LIST_ENTRY(buf) b_vnbufs; /* c: associated vnode */ 144 TAILQ_ENTRY(buf) b_freelist; /* c: position if not active */ 145 LIST_ENTRY(buf) b_wapbllist; /* c: transaction buffer list */ 146 daddr_t b_lblkno; /* c: logical block number */ 147 int b_freelistindex;/* c: free list index (BQ_) */ 148 u_int b_cflags; /* c: BC_* flags */ 149 struct vnode *b_vp; /* c: file vnode */ 150 151 kcondvar_t b_done; /* o: waiting on completion */ 152 u_int b_oflags; /* o: BO_* flags */ 153 kmutex_t *b_objlock; /* o: completion lock */ 154 }; 155 156 /* 157 * For portability with historic industry practice, the cylinder number has 158 * to be maintained in the `b_resid' field. 159 */ 160 #define b_cylinder b_resid /* Cylinder number for disksort(). */ 161 162 /* 163 * These flags are kept in b_cflags (owned by buffer cache). 164 */ 165 #define BC_AGE 0x00000001 /* Move to age queue when I/O done. */ 166 #define BC_BUSY 0x00000010 /* I/O in progress. */ 167 #define BC_INVAL 0x00002000 /* Does not contain valid info. */ 168 #define BC_NOCACHE 0x00008000 /* Do not cache block after use. */ 169 #define BC_WANTED 0x00800000 /* Process wants this buffer. */ 170 #define BC_VFLUSH 0x04000000 /* Buffer is being synced. */ 171 172 /* 173 * These flags are kept in b_oflags (owned by associated object). 174 */ 175 #define BO_DELWRI 0x00000080 /* Delay I/O until buffer reused. */ 176 #define BO_DONE 0x00000200 /* I/O completed. */ 177 178 /* 179 * These flags are kept in b_flags (owned by buffer holder). 180 */ 181 #define B_WRITE 0x00000000 /* Write buffer (pseudo flag). */ 182 #define B_ASYNC 0x00000004 /* Start I/O, do not wait. */ 183 #define B_COWDONE 0x00000400 /* Copy-on-write already done. */ 184 #define B_GATHERED 0x00001000 /* LFS: already in a segment. */ 185 #define B_LOCKED 0x00004000 /* Locked in core (not reusable). */ 186 #define B_PHYS 0x00040000 /* I/O to user memory. */ 187 #define B_RAW 0x00080000 /* Set by physio for raw transfers. */ 188 #define B_READ 0x00100000 /* Read buffer. */ 189 #define B_DEVPRIVATE 0x02000000 /* Device driver private flag. */ 190 191 #define BUF_FLAGBITS \ 192 "\20\1AGE\3ASYNC\4BAD\5BUSY\10DELWRI" \ 193 "\12DONE\13COWDONE\15GATHERED\16INVAL\17LOCKED\20NOCACHE" \ 194 "\23PHYS\24RAW\25READ\32DEVPRIVATE\33VFLUSH" 195 196 /* Avoid weird code due to B_WRITE being a "pseudo flag" */ 197 #define BUF_ISREAD(bp) (((bp)->b_flags & B_READ) == B_READ) 198 #define BUF_ISWRITE(bp) (((bp)->b_flags & B_READ) == B_WRITE) 199 200 /* 201 * This structure describes a clustered I/O. It is stored in the b_saveaddr 202 * field of the buffer on which I/O is done. At I/O completion, cluster 203 * callback uses the structure to parcel I/O's to individual buffers, and 204 * then free's this structure. 205 */ 206 struct cluster_save { 207 long bs_bcount; /* Saved b_bcount. */ 208 long bs_bufsize; /* Saved b_bufsize. */ 209 void *bs_saveaddr; /* Saved b_addr. */ 210 int bs_nchildren; /* Number of associated buffers. */ 211 struct buf *bs_children; /* List of associated buffers. */ 212 }; 213 214 /* 215 * Zero out the buffer's data area. 216 */ 217 #define clrbuf(bp) \ 218 do { \ 219 memset((bp)->b_data, 0, (u_int)(bp)->b_bcount); \ 220 (bp)->b_resid = 0; \ 221 } while (/* CONSTCOND */ 0) 222 223 /* Flags to low-level allocation routines. */ 224 #define B_CLRBUF 0x01 /* Request allocated buffer be cleared. */ 225 #define B_SYNC 0x02 /* Do all allocations synchronously. */ 226 #define B_METAONLY 0x04 /* Return indirect block buffer. */ 227 #define B_CONTIG 0x08 /* Allocate file contiguously. */ 228 229 /* Flags to bread() and breadn(). */ 230 #define B_MODIFY 0x01 /* Hint: caller might modify buffer */ 231 232 #ifdef _KERNEL 233 234 #define BIO_GETPRIO(bp) ((bp)->b_prio) 235 #define BIO_SETPRIO(bp, prio) (bp)->b_prio = (prio) 236 #define BIO_COPYPRIO(bp1, bp2) BIO_SETPRIO(bp1, BIO_GETPRIO(bp2)) 237 238 #define BPRIO_NPRIO 3 239 #define BPRIO_TIMECRITICAL 2 240 #define BPRIO_TIMELIMITED 1 241 #define BPRIO_TIMENONCRITICAL 0 242 #define BPRIO_DEFAULT BPRIO_TIMELIMITED 243 244 extern u_int nbuf; /* The number of buffer headers */ 245 246 /* 247 * Definitions for the buffer free lists. 248 */ 249 #define BQUEUES 4 /* number of free buffer queues */ 250 251 #define BQ_LOCKED 0 /* super-blocks &c */ 252 #define BQ_LRU 1 /* lru, useful buffers */ 253 #define BQ_AGE 2 /* rubbish */ 254 #define BQ_EMPTY 3 /* buffer headers with no memory */ 255 256 struct bqueue { 257 TAILQ_HEAD(, buf) bq_queue; 258 uint64_t bq_bytes; 259 buf_t *bq_marker; 260 }; 261 262 extern struct bqueue bufqueues[BQUEUES]; 263 264 __BEGIN_DECLS 265 int allocbuf(buf_t *, int, int); 266 void bawrite(buf_t *); 267 void bdwrite(buf_t *); 268 void biodone(buf_t *); 269 int biowait(buf_t *); 270 int bread(struct vnode *, daddr_t, int, struct kauth_cred *, int, buf_t **); 271 int breadn(struct vnode *, daddr_t, int, daddr_t *, int *, int, 272 struct kauth_cred *, int, buf_t **); 273 void brelsel(buf_t *, int); 274 void brelse(buf_t *, int); 275 void bremfree(buf_t *); 276 void bufinit(void); 277 void bufinit2(void); 278 int bwrite(buf_t *); 279 buf_t *getblk(struct vnode *, daddr_t, int, int, int); 280 buf_t *geteblk(int); 281 buf_t *incore(struct vnode *, daddr_t); 282 283 void minphys(buf_t *); 284 int physio(void (*)(buf_t *), buf_t *, dev_t, int, 285 void (*)(buf_t *), struct uio *); 286 287 void brelvp(buf_t *); 288 void reassignbuf(buf_t *, struct vnode *); 289 void bgetvp(struct vnode *, buf_t *); 290 int buf_syncwait(void); 291 u_long buf_memcalc(void); 292 int buf_drain(int); 293 int buf_setvalimit(vsize_t); 294 #if defined(DDB) || defined(DEBUGPRINT) 295 void vfs_buf_print(buf_t *, int, void (*)(const char *, ...) 296 __printflike(1, 2)); 297 #endif 298 buf_t *getiobuf(struct vnode *, bool); 299 void putiobuf(buf_t *); 300 void buf_init(buf_t *); 301 void buf_destroy(buf_t *); 302 int bbusy(buf_t *, bool, int, kmutex_t *); 303 304 void nestiobuf_iodone(buf_t *); 305 void nestiobuf_setup(buf_t *, buf_t *, int, size_t); 306 void nestiobuf_done(buf_t *, int, int); 307 308 __END_DECLS 309 #endif /* _KERNEL */ 310 #endif /* !_SYS_BUF_H_ */ 311