1 /* $NetBSD: buf.h,v 1.135 2024/05/12 10:34:56 rillig 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 #if defined(_KERNEL) 92 extern void (*biodone_vfs)(buf_t *); 93 #endif 94 95 /* 96 * The buffer header describes an I/O operation in the kernel. 97 * 98 * Field markings and the corresponding locks: 99 * 100 * b thread of execution that holds BC_BUSY, does not correspond 101 * directly to any particular LWP 102 * c bufcache_lock 103 * o b_objlock 104 * 105 * For buffers associated with a vnode, b_objlock points to vp->v_interlock. 106 * If not associated with a vnode, it points to the generic buffer_lock. 107 */ 108 109 /* required for the conditional union member below to be ~safe */ 110 #if defined(_KERNEL) 111 __CTASSERT(sizeof(struct work) <= sizeof(TAILQ_ENTRY(buf))); 112 #endif 113 114 struct buf { 115 union { 116 TAILQ_ENTRY(buf) u_actq; 117 rb_node_t u_rbnode; 118 #if defined(_KERNEL) 119 /* u_work is smaller than u_actq */ 120 struct work u_work; 121 #endif 122 } b_u; /* b: device driver queue */ 123 #define b_actq b_u.u_actq 124 #define b_work b_u.u_work 125 void (*b_iodone)(struct buf *);/* b: call when done */ 126 int b_error; /* b: errno value. */ 127 int b_resid; /* b: remaining I/O. */ 128 u_int b_flags; /* b: B_* flags */ 129 int b_prio; /* b: priority for queue */ 130 int b_bufsize; /* b: allocated size */ 131 int b_bcount; /* b: valid bytes in buffer */ 132 dev_t b_dev; /* b: associated device */ 133 void *b_data; /* b: fs private data */ 134 daddr_t b_blkno; /* b: physical block number 135 (partition relative) */ 136 daddr_t b_rawblkno; /* b: raw physical block number 137 (volume relative) */ 138 struct proc *b_proc; /* b: proc if BB_PHYS */ 139 void *b_saveaddr; /* b: saved b_data for physio */ 140 struct cpu_info *b_ci; /* b: originating CPU */ 141 142 /* 143 * b: private data for owner. 144 * - buffer cache buffers are owned by corresponding filesystem. 145 * - non-buffer cache buffers are owned by subsystem which 146 * allocated them. (filesystem, disk driver, etc) 147 */ 148 void *b_private; 149 off_t b_dcookie; /* NFS: Offset cookie if dir block */ 150 151 kcondvar_t b_busy; /* c: threads waiting on buf */ 152 void *b_unused; /* : unused */ 153 LIST_ENTRY(buf) b_hash; /* c: hash chain */ 154 LIST_ENTRY(buf) b_vnbufs; /* c: associated vnode */ 155 TAILQ_ENTRY(buf) b_freelist; /* c: position if not active */ 156 TAILQ_ENTRY(buf) b_wapbllist; /* c: transaction buffer list */ 157 daddr_t b_lblkno; /* c: logical block number */ 158 int b_freelistindex;/* c: free list index (BQ_) */ 159 u_int b_cflags; /* c: BC_* flags */ 160 struct vnode *b_vp; /* c: file vnode */ 161 162 kcondvar_t b_done; /* o: waiting on completion */ 163 u_int b_oflags; /* o: BO_* flags */ 164 kmutex_t *b_objlock; /* o: completion lock */ 165 }; 166 167 /* 168 * For portability with historic industry practice, the cylinder number has 169 * to be maintained in the `b_resid' field. 170 */ 171 #define b_cylinder b_resid /* Cylinder number for disksort(). */ 172 173 /* 174 * These flags are kept in b_cflags (owned by buffer cache). 175 */ 176 #define BC_AGE 0x00000001 /* Move to age queue when I/O done. */ 177 #define BC_BUSY 0x00000010 /* I/O in progress. */ 178 #define BC_INVAL 0x00002000 /* Does not contain valid info. */ 179 #define BC_NOCACHE 0x00008000 /* Do not cache block after use. */ 180 #define BC_WANTED 0x00800000 /* Process wants this buffer. */ 181 #define BC_VFLUSH 0x04000000 /* Buffer is being synced. */ 182 183 /* 184 * These flags are kept in b_oflags (owned by associated object). 185 */ 186 #define BO_DELWRI 0x00000080 /* Delay I/O until buffer reused. */ 187 #define BO_DONE 0x00000200 /* I/O completed. */ 188 189 /* 190 * These flags are kept in b_flags (owned by buffer holder). 191 */ 192 #define B_WRITE 0x00000000 /* Write buffer (pseudo flag). */ 193 #define B_ASYNC 0x00000004 /* Start I/O, do not wait. */ 194 #define B_COWDONE 0x00000400 /* Copy-on-write already done. */ 195 #define B_GATHERED 0x00001000 /* LFS: already in a segment. */ 196 #define B_LOCKED 0x00004000 /* Locked in core (not reusable). */ 197 #define B_PHYS 0x00040000 /* I/O to user memory. */ 198 #define B_RAW 0x00080000 /* Set by physio for raw transfers. */ 199 #define B_READ 0x00100000 /* Read buffer. */ 200 #define B_DEVPRIVATE 0x02000000 /* Device driver private flag. */ 201 #define B_MEDIA_FUA 0x08000000 /* Set Force Unit Access for media. */ 202 #define B_MEDIA_DPO 0x10000000 /* Set Disable Page Out for media. */ 203 204 #define BUF_FLAGBITS \ 205 "\20\1AGE\3ASYNC\4BAD\5BUSY\10DELWRI" \ 206 "\12DONE\13COWDONE\15GATHERED\16INVAL\17LOCKED\20NOCACHE" \ 207 "\23PHYS\24RAW\25READ\32DEVPRIVATE\33VFLUSH\34MEDIA_FUA\35MEDIA_DPO" 208 209 /* Avoid weird code due to B_WRITE being a "pseudo flag" */ 210 #define BUF_ISREAD(bp) (((bp)->b_flags & B_READ) == B_READ) 211 #define BUF_ISWRITE(bp) (((bp)->b_flags & B_READ) == B_WRITE) 212 213 /* Media flags, to be passed for nested I/O */ 214 #define B_MEDIA_FLAGS (B_MEDIA_FUA|B_MEDIA_DPO) 215 216 /* 217 * This structure describes a clustered I/O. It is stored in the b_saveaddr 218 * field of the buffer on which I/O is done. At I/O completion, cluster 219 * callback uses the structure to parcel I/O's to individual buffers, and 220 * then free's this structure. 221 */ 222 struct cluster_save { 223 long bs_bcount; /* Saved b_bcount. */ 224 long bs_bufsize; /* Saved b_bufsize. */ 225 void *bs_saveaddr; /* Saved b_addr. */ 226 int bs_nchildren; /* Number of associated buffers. */ 227 struct buf *bs_children; /* List of associated buffers. */ 228 }; 229 230 /* 231 * Zero out the buffer's data area. 232 */ 233 #define clrbuf(bp) \ 234 do { \ 235 memset((bp)->b_data, 0, (u_int)(bp)->b_bcount); \ 236 (bp)->b_resid = 0; \ 237 } while (0) 238 239 /* Flags to low-level allocation routines. */ 240 #define B_CLRBUF 0x01 /* Request allocated buffer be cleared. */ 241 #define B_SYNC 0x02 /* Do all allocations synchronously. */ 242 #define B_METAONLY 0x04 /* Return indirect block buffer. */ 243 #define B_CONTIG 0x08 /* Allocate file contiguously. */ 244 245 /* Flags to bread() and breadn(). */ 246 #define B_MODIFY 0x01 /* Hint: caller might modify buffer */ 247 248 #ifdef _KERNEL 249 250 #define BIO_GETPRIO(bp) ((bp)->b_prio) 251 #define BIO_SETPRIO(bp, prio) (bp)->b_prio = (prio) 252 #define BIO_COPYPRIO(bp1, bp2) BIO_SETPRIO(bp1, BIO_GETPRIO(bp2)) 253 254 #define BPRIO_NPRIO 3 255 #define BPRIO_TIMECRITICAL 2 256 #define BPRIO_TIMELIMITED 1 257 #define BPRIO_TIMENONCRITICAL 0 258 #define BPRIO_DEFAULT BPRIO_TIMELIMITED 259 260 __BEGIN_DECLS 261 /* 262 * bufferio(9) ops 263 */ 264 void biodone(buf_t *); 265 int biowait(buf_t *); 266 buf_t *getiobuf(struct vnode *, bool); 267 void putiobuf(buf_t *); 268 void nestiobuf_setup(buf_t *, buf_t *, int, size_t); 269 void nestiobuf_done(buf_t *, int, int); 270 271 void nestiobuf_iodone(buf_t *); 272 int physio(void (*)(buf_t *), buf_t *, dev_t, int, 273 void (*)(buf_t *), struct uio *); 274 275 /* 276 * buffercache(9) ops 277 */ 278 int bread(struct vnode *, daddr_t, int, int, buf_t **); 279 int breadn(struct vnode *, daddr_t, int, daddr_t *, int *, int, 280 int, buf_t **); 281 int bwrite(buf_t *); 282 void bawrite(buf_t *); 283 void bdwrite(buf_t *); 284 buf_t *getblk(struct vnode *, daddr_t, int, int, int); 285 buf_t *geteblk(int); 286 buf_t *incore(struct vnode *, daddr_t); 287 int allocbuf(buf_t *, int, int); 288 void brelsel(buf_t *, int); 289 void brelse(buf_t *, int); 290 void binvalbuf(struct vnode *, daddr_t); 291 292 /* 293 * So-far indeterminate ops that might belong to either 294 * bufferio(9) or buffercache(9). 295 */ 296 void bremfree(buf_t *); 297 void bufinit(void); 298 void bufinit2(void); 299 void minphys(buf_t *); 300 void brelvp(buf_t *); 301 void reassignbuf(buf_t *, struct vnode *); 302 void bgetvp(struct vnode *, buf_t *); 303 u_long buf_memcalc(void); 304 int buf_drain(int); 305 int buf_setvalimit(vsize_t); 306 #if defined(DDB) || defined(DEBUGPRINT) 307 void vfs_buf_print(buf_t *, int, void (*)(const char *, ...) 308 __printflike(1, 2)); 309 #endif 310 void buf_init(buf_t *); 311 void buf_destroy(buf_t *); 312 int bbusy(buf_t *, bool, int, kmutex_t *); 313 u_int buf_nbuf(void); 314 315 void biohist_init(void); 316 317 __END_DECLS 318 #endif /* _KERNEL */ 319 #endif /* !_SYS_BUF_H_ */ 320