1 /* $OpenBSD: buf.h,v 1.93 2013/11/21 01:16:52 dlg 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 46 #define NOLIST ((struct buf *)0x87654321) 47 48 struct buf; 49 struct vnode; 50 51 struct buf_rb_bufs; 52 RB_PROTOTYPE(buf_rb_bufs, buf, b_rbbufs, rb_buf_compare); 53 54 LIST_HEAD(bufhead, buf); 55 56 /* 57 * To avoid including <ufs/ffs/softdep.h> 58 */ 59 60 LIST_HEAD(workhead, worklist); 61 62 /* 63 * Buffer queues 64 */ 65 #define BUFQ_NSCAN_N 128 66 #define BUFQ_FIFO 0 67 #define BUFQ_NSCAN 1 68 #define BUFQ_DEFAULT BUFQ_NSCAN 69 #define BUFQ_HOWMANY 2 70 71 /* 72 * Write limits for bufq - defines high and low water marks for how 73 * many kva slots are allowed to be consumed to parallelize writes from 74 * the buffer cache from any individual bufq. 75 */ 76 #define BUFQ_HI 128 77 #define BUFQ_LOW 64 78 79 struct bufq_impl; 80 81 struct bufq { 82 SLIST_ENTRY(bufq) bufq_entries; 83 struct mutex bufq_mtx; 84 void *bufq_data; 85 u_int bufq_outstanding; 86 u_int bufq_hi; 87 u_int bufq_low; 88 int bufq_waiting; 89 int bufq_stop; 90 int bufq_type; 91 const struct bufq_impl *bufq_impl; 92 }; 93 94 int bufq_init(struct bufq *, int); 95 int bufq_switch(struct bufq *, int); 96 void bufq_destroy(struct bufq *); 97 98 void bufq_queue(struct bufq *, struct buf *); 99 struct buf *bufq_dequeue(struct bufq *); 100 void bufq_requeue(struct bufq *, struct buf *); 101 int bufq_peek(struct bufq *); 102 void bufq_drain(struct bufq *); 103 104 void bufq_wait(struct bufq *, struct buf *); 105 void bufq_done(struct bufq *, struct buf *); 106 void bufq_quiesce(void); 107 void bufq_restart(void); 108 109 /* disksort */ 110 struct bufq_disksort { 111 struct buf *bqd_actf; 112 struct buf **bqd_actb; 113 }; 114 115 /* fifo */ 116 SIMPLEQ_HEAD(bufq_fifo_head, buf); 117 struct bufq_fifo { 118 SIMPLEQ_ENTRY(buf) bqf_entries; 119 }; 120 121 /* nscan */ 122 SIMPLEQ_HEAD(bufq_nscan_head, buf); 123 struct bufq_nscan { 124 SIMPLEQ_ENTRY(buf) bqf_entries; 125 }; 126 127 /* bufq link in struct buf */ 128 union bufq_data { 129 struct bufq_disksort bufq_data_disksort; 130 struct bufq_fifo bufq_data_fifo; 131 struct bufq_nscan bufq_data_nscan; 132 }; 133 134 /* 135 * These are currently used only by the soft dependency code, hence 136 * are stored once in a global variable. If other subsystems wanted 137 * to use these hooks, a pointer to a set of bio_ops could be added 138 * to each buffer. 139 */ 140 extern struct bio_ops { 141 void (*io_start)(struct buf *); 142 void (*io_complete)(struct buf *); 143 void (*io_deallocate)(struct buf *); 144 void (*io_movedeps)(struct buf *, struct buf *); 145 int (*io_countdeps)(struct buf *, int, int); 146 } bioops; 147 148 /* XXX: disksort(); */ 149 #define b_actf b_bufq.bufq_data_disksort.bqd_actf 150 #define b_actb b_bufq.bufq_data_disksort.bqd_actb 151 152 /* The buffer header describes an I/O operation in the kernel. */ 153 struct buf { 154 RB_ENTRY(buf) b_rbbufs; /* vnode "hash" tree */ 155 LIST_ENTRY(buf) b_list; /* All allocated buffers. */ 156 LIST_ENTRY(buf) b_vnbufs; /* Buffer's associated vnode. */ 157 TAILQ_ENTRY(buf) b_freelist; /* Free list position if not active. */ 158 time_t b_synctime; /* Time this buffer should be flushed */ 159 struct proc *b_proc; /* Associated proc; NULL if kernel. */ 160 volatile long b_flags; /* B_* flags. */ 161 int b_error; /* Errno value. */ 162 long b_bufsize; /* Allocated buffer size. */ 163 long b_bcount; /* Valid bytes in buffer. */ 164 size_t b_resid; /* Remaining I/O. */ 165 dev_t b_dev; /* Device associated with buffer. */ 166 caddr_t b_data; /* associated data */ 167 void *b_saveaddr; /* Original b_data for physio. */ 168 169 TAILQ_ENTRY(buf) b_valist; /* LRU of va to reuse. */ 170 171 union bufq_data b_bufq; 172 struct bufq *b_bq; /* What bufq this buf is on */ 173 174 struct uvm_object *b_pobj; /* Object containing the pages */ 175 off_t b_poffs; /* Offset within object */ 176 177 daddr_t b_lblkno; /* Logical block number. */ 178 daddr_t b_blkno; /* Underlying physical block number. */ 179 /* Function to call upon completion. 180 * Will be called at splbio(). */ 181 void (*b_iodone)(struct buf *); 182 struct vnode *b_vp; /* Device vnode. */ 183 int b_dirtyoff; /* Offset in buffer of dirty region. */ 184 int b_dirtyend; /* Offset of end of dirty region. */ 185 int b_validoff; /* Offset in buffer of valid region. */ 186 int b_validend; /* Offset of end of valid region. */ 187 struct workhead b_dep; /* List of filesystem dependencies. */ 188 }; 189 190 /* Device driver compatibility definitions. */ 191 #define b_active b_bcount /* Driver queue head: drive active. */ 192 193 /* 194 * These flags are kept in b_flags. 195 */ 196 #define B_WRITE 0x00000000 /* Write buffer (pseudo flag). */ 197 #define B_AGE 0x00000001 /* Move to age queue when I/O done. */ 198 #define B_NEEDCOMMIT 0x00000002 /* Needs committing to stable storage */ 199 #define B_ASYNC 0x00000004 /* Start I/O, do not wait. */ 200 #define B_BAD 0x00000008 /* Bad block revectoring in progress. */ 201 #define B_BUSY 0x00000010 /* I/O in progress. */ 202 #define B_CACHE 0x00000020 /* Bread found us in the cache. */ 203 #define B_CALL 0x00000040 /* Call b_iodone from biodone. */ 204 #define B_DELWRI 0x00000080 /* Delay I/O until buffer reused. */ 205 #define B_DONE 0x00000100 /* I/O completed. */ 206 #define B_EINTR 0x00000200 /* I/O was interrupted */ 207 #define B_ERROR 0x00000400 /* I/O error occurred. */ 208 #define B_INVAL 0x00000800 /* Does not contain valid info. */ 209 #define B_NOCACHE 0x00001000 /* Do not cache block after use. */ 210 #define B_PHYS 0x00002000 /* I/O to user memory. */ 211 #define B_RAW 0x00004000 /* Set by physio for raw transfers. */ 212 #define B_READ 0x00008000 /* Read buffer. */ 213 #define B_WANTED 0x00010000 /* Process wants this buffer. */ 214 #define B_WRITEINPROG 0x00020000 /* Write in progress. */ 215 #define B_XXX 0x00040000 /* Debugging flag. */ 216 #define B_DEFERRED 0x00080000 /* Skipped over for cleaning */ 217 #define B_SCANNED 0x00100000 /* Block already pushed during sync */ 218 #define B_PDAEMON 0x00200000 /* I/O started by pagedaemon */ 219 #define B_RELEASED 0x00400000 /* free this buffer after its kvm */ 220 221 #define B_BITS "\20\001AGE\002NEEDCOMMIT\003ASYNC\004BAD\005BUSY" \ 222 "\006CACHE\007CALL\010DELWRI\011DONE\012EINTR\013ERROR" \ 223 "\014INVAL\015NOCACHE\016PHYS\017RAW\020READ" \ 224 "\021WANTED\022WRITEINPROG\023XXX(FORMAT)\024DEFERRED" \ 225 "\025SCANNED\026DAEMON\027RELEASED" 226 227 /* 228 * This structure describes a clustered I/O. It is stored in the b_saveaddr 229 * field of the buffer on which I/O is done. At I/O completion, cluster 230 * callback uses the structure to parcel I/O's to individual buffers, and 231 * then free's this structure. 232 */ 233 struct cluster_save { 234 long bs_bcount; /* Saved b_bcount. */ 235 long bs_bufsize; /* Saved b_bufsize. */ 236 void *bs_saveaddr; /* Saved b_addr. */ 237 int bs_nchildren; /* Number of associated buffers. */ 238 struct buf **bs_children; /* List of associated buffers. */ 239 }; 240 241 /* 242 * Zero out the buffer's data area. 243 */ 244 #define clrbuf(bp) { \ 245 bzero((bp)->b_data, (u_int)(bp)->b_bcount); \ 246 (bp)->b_resid = 0; \ 247 } 248 249 250 /* Flags to low-level allocation routines. */ 251 #define B_CLRBUF 0x01 /* Request allocated buffer be cleared. */ 252 #define B_SYNC 0x02 /* Do all allocations synchronously. */ 253 254 struct cluster_info { 255 daddr_t ci_lastr; /* last read (read-ahead) */ 256 daddr_t ci_lastw; /* last write (write cluster) */ 257 daddr_t ci_cstart; /* start block of cluster */ 258 daddr_t ci_lasta; /* last allocation */ 259 int ci_clen; /* length of current cluster */ 260 int ci_ralen; /* Read-ahead length */ 261 daddr_t ci_maxra; /* last readahead block */ 262 }; 263 264 #ifdef _KERNEL 265 __BEGIN_DECLS 266 /* Kva slots (of size MAXPHYS) reserved for syncer and cleaner. */ 267 #define RESERVE_SLOTS 4 268 /* Buffer cache pages reserved for syncer and cleaner. */ 269 #define RESERVE_PAGES (RESERVE_SLOTS * MAXPHYS / PAGE_SIZE) 270 /* Minimum size of the buffer cache, in pages. */ 271 #define BCACHE_MIN (RESERVE_PAGES * 2) 272 #define UNCLEAN_PAGES (bcstats.numbufpages - bcstats.numcleanpages) 273 274 extern struct proc *cleanerproc; 275 extern long bufpages; /* Max number of pages for buffers' data */ 276 extern struct pool bufpool; 277 extern struct bufhead bufhead; 278 279 void bawrite(struct buf *); 280 void bdwrite(struct buf *); 281 void biodone(struct buf *); 282 int biowait(struct buf *); 283 int bread(struct vnode *, daddr_t, int, struct buf **); 284 int breadn(struct vnode *, daddr_t, int, daddr_t *, int *, int, 285 struct buf **); 286 void brelse(struct buf *); 287 void bremfree(struct buf *); 288 void bufinit(void); 289 void buf_dirty(struct buf *); 290 void buf_undirty(struct buf *); 291 int bwrite(struct buf *); 292 struct buf *getblk(struct vnode *, daddr_t, int, int, int); 293 struct buf *geteblk(int); 294 struct buf *incore(struct vnode *, daddr_t); 295 296 /* 297 * buf_kvm_init initializes the kvm handling for buffers. 298 * buf_acquire sets the B_BUSY flag and ensures that the buffer is 299 * mapped in the kvm. 300 * buf_release clears the B_BUSY flag and allows the buffer to become 301 * unmapped. 302 * buf_unmap is for internal use only. Unmaps the buffer from kvm. 303 */ 304 void buf_mem_init(vsize_t); 305 void buf_acquire(struct buf *); 306 void buf_acquire_unmapped(struct buf *); 307 void buf_acquire_nomap(struct buf *); 308 void buf_map(struct buf *); 309 void buf_release(struct buf *); 310 int buf_dealloc_mem(struct buf *); 311 void buf_fix_mapping(struct buf *, vsize_t); 312 void buf_alloc_pages(struct buf *, vsize_t); 313 void buf_free_pages(struct buf *); 314 315 316 void minphys(struct buf *bp); 317 int physio(void (*strategy)(struct buf *), dev_t dev, int flags, 318 void (*minphys)(struct buf *), struct uio *uio); 319 void brelvp(struct buf *); 320 void reassignbuf(struct buf *); 321 void bgetvp(struct vnode *, struct buf *); 322 323 void buf_replacevnode(struct buf *, struct vnode *); 324 void buf_daemon(struct proc *); 325 void buf_replacevnode(struct buf *, struct vnode *); 326 void buf_daemon(struct proc *); 327 int bread_cluster(struct vnode *, daddr_t, int, struct buf **); 328 329 #ifdef DEBUG 330 void buf_print(struct buf *); 331 #endif 332 333 static __inline void 334 buf_start(struct buf *bp) 335 { 336 if (bioops.io_start) 337 (*bioops.io_start)(bp); 338 } 339 340 static __inline void 341 buf_complete(struct buf *bp) 342 { 343 if (bioops.io_complete) 344 (*bioops.io_complete)(bp); 345 } 346 347 static __inline void 348 buf_deallocate(struct buf *bp) 349 { 350 if (bioops.io_deallocate) 351 (*bioops.io_deallocate)(bp); 352 } 353 354 static __inline void 355 buf_movedeps(struct buf *bp, struct buf *bp2) 356 { 357 if (bioops.io_movedeps) 358 (*bioops.io_movedeps)(bp, bp2); 359 } 360 361 static __inline int 362 buf_countdeps(struct buf *bp, int i, int islocked) 363 { 364 if (bioops.io_countdeps) 365 return ((*bioops.io_countdeps)(bp, i, islocked)); 366 else 367 return (0); 368 } 369 370 void cluster_write(struct buf *, struct cluster_info *, u_quad_t); 371 372 __END_DECLS 373 #endif /* _KERNEL */ 374 #endif /* !_SYS_BUF_H_ */ 375