1 /* $OpenBSD: buf.h,v 1.76 2011/04/07 19:07:42 beck Exp $ */ 2 /* $NetBSD: buf.h,v 1.25 1997/04/09 21:12:17 mycroft Exp $ */ 3 4 /* 5 * Copyright (c) 1982, 1986, 1989, 1993 6 * The Regents of the University of California. All rights reserved. 7 * (c) UNIX System Laboratories, Inc. 8 * All or some portions of this file are derived from material licensed 9 * to the University of California by American Telephone and Telegraph 10 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 11 * the permission of UNIX System Laboratories, Inc. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)buf.h 8.7 (Berkeley) 1/21/94 38 */ 39 40 #ifndef _SYS_BUF_H_ 41 #define _SYS_BUF_H_ 42 #include <sys/queue.h> 43 #include <sys/tree.h> 44 #include <sys/mutex.h> 45 #include <sys/workq.h> 46 47 #define NOLIST ((struct buf *)0x87654321) 48 49 struct buf; 50 struct vnode; 51 52 struct buf_rb_bufs; 53 RB_PROTOTYPE(buf_rb_bufs, buf, b_rbbufs, rb_buf_compare); 54 55 LIST_HEAD(bufhead, buf); 56 57 /* 58 * To avoid including <ufs/ffs/softdep.h> 59 */ 60 61 LIST_HEAD(workhead, worklist); 62 63 /* 64 * Buffer queues 65 */ 66 #define BUFQ_DISKSORT 0 67 #define BUFQ_FIFO 1 68 #define BUFQ_DEFAULT BUFQ_DISKSORT 69 #define BUFQ_HOWMANY 2 70 71 struct bufq_impl; 72 73 struct bufq { 74 SLIST_ENTRY(bufq) bufq_entries; 75 struct mutex bufq_mtx; 76 void *bufq_data; 77 u_int bufq_outstanding; 78 int bufq_stop; 79 int bufq_type; 80 const struct bufq_impl *bufq_impl; 81 }; 82 83 int bufq_init(struct bufq *, int); 84 int bufq_switch(struct bufq *, int); 85 void bufq_destroy(struct bufq *); 86 87 void bufq_queue(struct bufq *, struct buf *); 88 struct buf *bufq_dequeue(struct bufq *); 89 void bufq_requeue(struct bufq *, struct buf *); 90 int bufq_peek(struct bufq *); 91 void bufq_drain(struct bufq *); 92 93 void bufq_done(struct bufq *, struct buf *); 94 void bufq_quiesce(void); 95 void bufq_restart(void); 96 97 /* disksort */ 98 struct bufq_disksort { 99 struct buf *bqd_actf; 100 struct buf **bqd_actb; 101 }; 102 103 /* fifo */ 104 SIMPLEQ_HEAD(bufq_fifo_head, buf); 105 struct bufq_fifo { 106 SIMPLEQ_ENTRY(buf) bqf_entries; 107 }; 108 109 /* Abuse bufq_fifo, for swapping to regular files. */ 110 struct bufq_swapreg { 111 SIMPLEQ_ENTRY(buf) bqf_entries; 112 struct workq_task bqf_wqtask; 113 114 }; 115 116 /* bufq link in struct buf */ 117 union bufq_data { 118 struct bufq_disksort bufq_data_disksort; 119 struct bufq_fifo bufq_data_fifo; 120 struct bufq_swapreg bufq_swapreg; 121 }; 122 123 /* 124 * These are currently used only by the soft dependency code, hence 125 * are stored once in a global variable. If other subsystems wanted 126 * to use these hooks, a pointer to a set of bio_ops could be added 127 * to each buffer. 128 */ 129 extern struct bio_ops { 130 void (*io_start)(struct buf *); 131 void (*io_complete)(struct buf *); 132 void (*io_deallocate)(struct buf *); 133 void (*io_movedeps)(struct buf *, struct buf *); 134 int (*io_countdeps)(struct buf *, int, int); 135 } bioops; 136 137 /* XXX: disksort(); */ 138 #define b_actf b_bufq.bufq_data_disksort.bqd_actf 139 #define b_actb b_bufq.bufq_data_disksort.bqd_actb 140 141 /* The buffer header describes an I/O operation in the kernel. */ 142 struct buf { 143 RB_ENTRY(buf) b_rbbufs; /* vnode "hash" tree */ 144 LIST_ENTRY(buf) b_list; /* All allocated buffers. */ 145 LIST_ENTRY(buf) b_vnbufs; /* Buffer's associated vnode. */ 146 TAILQ_ENTRY(buf) b_freelist; /* Free list position if not active. */ 147 time_t b_synctime; /* Time this buffer should be flushed */ 148 struct proc *b_proc; /* Associated proc; NULL if kernel. */ 149 volatile long b_flags; /* B_* flags. */ 150 int b_error; /* Errno value. */ 151 long b_bufsize; /* Allocated buffer size. */ 152 long b_bcount; /* Valid bytes in buffer. */ 153 size_t b_resid; /* Remaining I/O. */ 154 dev_t b_dev; /* Device associated with buffer. */ 155 caddr_t b_data; /* associated data */ 156 void *b_saveaddr; /* Original b_data for physio. */ 157 158 TAILQ_ENTRY(buf) b_valist; /* LRU of va to reuse. */ 159 160 union bufq_data b_bufq; 161 struct bufq *b_bq; /* What bufq this buf is on */ 162 163 struct uvm_object *b_pobj; /* Object containing the pages */ 164 off_t b_poffs; /* Offset within object */ 165 166 daddr64_t b_lblkno; /* Logical block number. */ 167 daddr64_t b_blkno; /* Underlying physical block number. */ 168 /* Function to call upon completion. 169 * Will be called at splbio(). */ 170 void (*b_iodone)(struct buf *); 171 struct vnode *b_vp; /* Device vnode. */ 172 int b_dirtyoff; /* Offset in buffer of dirty region. */ 173 int b_dirtyend; /* Offset of end of dirty region. */ 174 int b_validoff; /* Offset in buffer of valid region. */ 175 int b_validend; /* Offset of end of valid region. */ 176 struct workhead b_dep; /* List of filesystem dependencies. */ 177 }; 178 179 /* 180 * For portability with historic industry practice, the cylinder number has 181 * to be maintained in the `b_resid' field. 182 */ 183 #define b_cylinder b_resid /* Cylinder number for disksort(). */ 184 185 /* Device driver compatibility definitions. */ 186 #define b_active b_bcount /* Driver queue head: drive active. */ 187 #define b_errcnt b_resid /* Retry count while I/O in progress. */ 188 189 /* 190 * These flags are kept in b_flags. 191 */ 192 #define B_WRITE 0x00000000 /* Write buffer (pseudo flag). */ 193 #define B_AGE 0x00000001 /* Move to age queue when I/O done. */ 194 #define B_NEEDCOMMIT 0x00000002 /* Needs committing to stable storage */ 195 #define B_ASYNC 0x00000004 /* Start I/O, do not wait. */ 196 #define B_BAD 0x00000008 /* Bad block revectoring in progress. */ 197 #define B_BUSY 0x00000010 /* I/O in progress. */ 198 #define B_CACHE 0x00000020 /* Bread found us in the cache. */ 199 #define B_CALL 0x00000040 /* Call b_iodone from biodone. */ 200 #define B_DELWRI 0x00000080 /* Delay I/O until buffer reused. */ 201 #define B_DONE 0x00000100 /* I/O completed. */ 202 #define B_EINTR 0x00000200 /* I/O was interrupted */ 203 #define B_ERROR 0x00000400 /* I/O error occurred. */ 204 #define B_INVAL 0x00000800 /* Does not contain valid info. */ 205 #define B_NOCACHE 0x00001000 /* Do not cache block after use. */ 206 #define B_PHYS 0x00002000 /* I/O to user memory. */ 207 #define B_RAW 0x00004000 /* Set by physio for raw transfers. */ 208 #define B_READ 0x00008000 /* Read buffer. */ 209 #define B_WANTED 0x00010000 /* Process wants this buffer. */ 210 #define B_WRITEINPROG 0x00020000 /* Write in progress. */ 211 #define B_XXX 0x00040000 /* Debugging flag. */ 212 #define B_DEFERRED 0x00080000 /* Skipped over for cleaning */ 213 #define B_SCANNED 0x00100000 /* Block already pushed during sync */ 214 #define B_PDAEMON 0x00200000 /* I/O started by pagedaemon */ 215 #define B_RELEASED 0x00400000 /* free this buffer after its kvm */ 216 #define B_NOTMAPPED 0x00800000 /* BUSY, but not necessarily mapped */ 217 218 #define B_BITS "\20\001AGE\002NEEDCOMMIT\003ASYNC\004BAD\005BUSY" \ 219 "\006CACHE\007CALL\010DELWRI\011DONE\012EINTR\013ERROR" \ 220 "\014INVAL\015NOCACHE\016PHYS\017RAW\020READ" \ 221 "\021WANTED\022WRITEINPROG\023XXX(FORMAT)\024DEFERRED" \ 222 "\025SCANNED\026DAEMON\027RELEASED\030NOTMAPPED" 223 224 /* 225 * This structure describes a clustered I/O. It is stored in the b_saveaddr 226 * field of the buffer on which I/O is done. At I/O completion, cluster 227 * callback uses the structure to parcel I/O's to individual buffers, and 228 * then free's this structure. 229 */ 230 struct cluster_save { 231 long bs_bcount; /* Saved b_bcount. */ 232 long bs_bufsize; /* Saved b_bufsize. */ 233 void *bs_saveaddr; /* Saved b_addr. */ 234 int bs_nchildren; /* Number of associated buffers. */ 235 struct buf **bs_children; /* List of associated buffers. */ 236 }; 237 238 /* 239 * Zero out the buffer's data area. 240 */ 241 #define clrbuf(bp) { \ 242 bzero((bp)->b_data, (u_int)(bp)->b_bcount); \ 243 (bp)->b_resid = 0; \ 244 } 245 246 247 /* Flags to low-level allocation routines. */ 248 #define B_CLRBUF 0x01 /* Request allocated buffer be cleared. */ 249 #define B_SYNC 0x02 /* Do all allocations synchronously. */ 250 251 struct cluster_info { 252 daddr64_t ci_lastr; /* last read (read-ahead) */ 253 daddr64_t ci_lastw; /* last write (write cluster) */ 254 daddr64_t ci_cstart; /* start block of cluster */ 255 daddr64_t ci_lasta; /* last allocation */ 256 int ci_clen; /* length of current cluster */ 257 int ci_ralen; /* Read-ahead length */ 258 daddr64_t ci_maxra; /* last readahead block */ 259 }; 260 261 #ifdef _KERNEL 262 __BEGIN_DECLS 263 extern int bufpages; /* Max number of pages for buffers' data */ 264 extern struct pool bufpool; 265 extern struct bufhead bufhead; 266 267 void bawrite(struct buf *); 268 void bdwrite(struct buf *); 269 void biodone(struct buf *); 270 int biowait(struct buf *); 271 int bread(struct vnode *, daddr64_t, int, struct ucred *, struct buf **); 272 int breadn(struct vnode *, daddr64_t, int, daddr64_t *, int *, int, 273 struct ucred *, struct buf **); 274 void brelse(struct buf *); 275 void bremfree(struct buf *); 276 void bufinit(void); 277 void buf_dirty(struct buf *); 278 void buf_undirty(struct buf *); 279 int bwrite(struct buf *); 280 struct buf *getblk(struct vnode *, daddr64_t, int, int, int); 281 struct buf *geteblk(int); 282 struct buf *incore(struct vnode *, daddr64_t); 283 284 /* 285 * buf_kvm_init initializes the kvm handling for buffers. 286 * buf_acquire sets the B_BUSY flag and ensures that the buffer is 287 * mapped in the kvm. 288 * buf_release clears the B_BUSY flag and allows the buffer to become 289 * unmapped. 290 * buf_unmap is for internal use only. Unmaps the buffer from kvm. 291 */ 292 void buf_mem_init(vsize_t); 293 void buf_acquire(struct buf *); 294 void buf_acquire_unmapped(struct buf *); 295 void buf_map(struct buf *); 296 void buf_release(struct buf *); 297 int buf_dealloc_mem(struct buf *); 298 void buf_fix_mapping(struct buf *, vsize_t); 299 void buf_alloc_pages(struct buf *, vsize_t); 300 void buf_free_pages(struct buf *); 301 302 303 void minphys(struct buf *bp); 304 int physio(void (*strategy)(struct buf *), dev_t dev, int flags, 305 void (*minphys)(struct buf *), struct uio *uio); 306 void brelvp(struct buf *); 307 void reassignbuf(struct buf *); 308 void bgetvp(struct vnode *, struct buf *); 309 310 void buf_replacevnode(struct buf *, struct vnode *); 311 void buf_daemon(struct proc *); 312 void buf_replacevnode(struct buf *, struct vnode *); 313 void buf_daemon(struct proc *); 314 int bread_cluster(struct vnode *, daddr64_t, int, struct buf **); 315 316 #ifdef DEBUG 317 void buf_print(struct buf *); 318 #endif 319 320 static __inline void 321 buf_start(struct buf *bp) 322 { 323 if (bioops.io_start) 324 (*bioops.io_start)(bp); 325 } 326 327 static __inline void 328 buf_complete(struct buf *bp) 329 { 330 if (bioops.io_complete) 331 (*bioops.io_complete)(bp); 332 } 333 334 static __inline void 335 buf_deallocate(struct buf *bp) 336 { 337 if (bioops.io_deallocate) 338 (*bioops.io_deallocate)(bp); 339 } 340 341 static __inline void 342 buf_movedeps(struct buf *bp, struct buf *bp2) 343 { 344 if (bioops.io_movedeps) 345 (*bioops.io_movedeps)(bp, bp2); 346 } 347 348 static __inline int 349 buf_countdeps(struct buf *bp, int i, int islocked) 350 { 351 if (bioops.io_countdeps) 352 return ((*bioops.io_countdeps)(bp, i, islocked)); 353 else 354 return (0); 355 } 356 357 void cluster_write(struct buf *, struct cluster_info *, u_quad_t); 358 359 __END_DECLS 360 #endif 361 #endif /* !_SYS_BUF_H_ */ 362