1 /* 2 * Copyright (c) 1982, 1986, 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)buf.h 8.9 (Berkeley) 3/30/95 39 * $FreeBSD: src/sys/sys/buf.h,v 1.88.2.10 2003/01/25 19:02:23 dillon Exp $ 40 * $DragonFly: src/sys/sys/buf.h,v 1.12 2005/04/15 19:08:13 dillon Exp $ 41 */ 42 43 #ifndef _SYS_BUF_H_ 44 #define _SYS_BUF_H_ 45 46 #ifndef _SYS_QUEUE_H_ 47 #include <sys/queue.h> 48 #endif 49 #ifndef _SYS_LOCK_H_ 50 #include <sys/lock.h> 51 #endif 52 #ifndef _SYS_DEVICE_H_ 53 #include <sys/device.h> 54 #endif 55 56 #ifndef _SYS_XIO_H_ 57 #include <sys/xio.h> 58 #endif 59 #ifndef _SYS_TREE_H_ 60 #include <sys/tree.h> 61 #endif 62 63 struct buf; 64 struct mount; 65 struct vnode; 66 struct xio; 67 68 struct buf_rb_tree; 69 RB_PROTOTYPE(buf_rb_tree, buf, b_rbnode, rb_buf_compare); 70 71 /* 72 * To avoid including <ufs/ffs/softdep.h> 73 */ 74 LIST_HEAD(workhead, worklist); 75 /* 76 * These are currently used only by the soft dependency code, hence 77 * are stored once in a global variable. If other subsystems wanted 78 * to use these hooks, a pointer to a set of bio_ops could be added 79 * to each buffer. 80 */ 81 extern struct bio_ops { 82 void (*io_start) (struct buf *); 83 void (*io_complete) (struct buf *); 84 void (*io_deallocate) (struct buf *); 85 int (*io_fsync) (struct vnode *); 86 int (*io_sync) (struct mount *); 87 void (*io_movedeps) (struct buf *, struct buf *); 88 int (*io_countdeps) (struct buf *, int); 89 } bioops; 90 91 struct iodone_chain { 92 long ic_prev_flags; 93 void (*ic_prev_iodone) (struct buf *); 94 void *ic_prev_iodone_chain; 95 struct { 96 long ia_long; 97 void *ia_ptr; 98 } ic_args[5]; 99 }; 100 101 /* 102 * The buffer header describes an I/O operation in the kernel. 103 * 104 * NOTES: 105 * b_bufsize, b_bcount. b_bufsize is the allocation size of the 106 * buffer, either DEV_BSIZE or PAGE_SIZE aligned. b_bcount is the 107 * originally requested buffer size and can serve as a bounds check 108 * against EOF. For most, but not all uses, b_bcount == b_bufsize. 109 * 110 * b_dirtyoff, b_dirtyend. Buffers support piecemeal, unaligned 111 * ranges of dirty data that need to be written to backing store. 112 * The range is typically clipped at b_bcount ( not b_bufsize ). 113 * 114 * b_resid. Number of bytes remaining in I/O. After an I/O operation 115 * completes, b_resid is usually 0 indicating 100% success. 116 */ 117 struct buf { 118 LIST_ENTRY(buf) b_hash; /* Hash chain. */ 119 RB_ENTRY(buf) b_rbnode; /* Red-Black node in vnode RB tree */ 120 TAILQ_ENTRY(buf) b_freelist; /* Free list position if not active. */ 121 TAILQ_ENTRY(buf) b_act; /* Device driver queue when active. *new* */ 122 long b_flags; /* B_* flags. */ 123 unsigned short b_qindex; /* buffer queue index */ 124 unsigned char b_xflags; /* extra flags */ 125 struct lock b_lock; /* Buffer lock */ 126 int b_error; /* Errno value. */ 127 long b_bufsize; /* Allocated buffer size. */ 128 long b_runningbufspace; /* when I/O is running, pipelining */ 129 long b_bcount; /* Valid bytes in buffer. */ 130 long b_resid; /* Remaining I/O. */ 131 dev_t b_dev; /* Device associated with buffer. */ 132 caddr_t b_data; /* Memory, superblocks, indirect etc. */ 133 caddr_t b_kvabase; /* base kva for buffer */ 134 int b_kvasize; /* size of kva for buffer */ 135 daddr_t b_lblkno; /* Logical block number. */ 136 daddr_t b_blkno; /* Underlying physical block number. */ 137 off_t b_offset; /* Offset into file */ 138 /* Function to call upon completion. */ 139 void (*b_iodone) (struct buf *); 140 /* For nested b_iodone's. */ 141 struct iodone_chain *b_iodone_chain; 142 struct vnode *b_vp; /* Device vnode. */ 143 int b_dirtyoff; /* Offset in buffer of dirty region. */ 144 int b_dirtyend; /* Offset of end of dirty region. */ 145 daddr_t b_pblkno; /* physical block number */ 146 void *b_saveaddr; /* Original b_addr for physio. */ 147 void *b_driver1; /* for private use by the driver */ 148 void *b_caller1; /* for private use by the caller */ 149 union pager_info { 150 void *pg_spc; 151 int pg_reqpage; 152 } b_pager; 153 union cluster_info { 154 TAILQ_HEAD(cluster_list_head, buf) cluster_head; 155 TAILQ_ENTRY(buf) cluster_entry; 156 } b_cluster; 157 struct xio b_xio; /* page list management for buffer head. */ 158 struct workhead b_dep; /* List of filesystem dependencies. */ 159 struct chain_info { /* buffer chaining */ 160 struct buf *parent; 161 int count; 162 } b_chain; 163 }; 164 165 #define b_spc b_pager.pg_spc 166 167 /* 168 * These flags are kept in b_flags. 169 * 170 * Notes: 171 * 172 * B_ASYNC VOP calls on bp's are usually async whether or not 173 * B_ASYNC is set, but some subsystems, such as NFS, like 174 * to know what is best for the caller so they can 175 * optimize the I/O. 176 * 177 * B_PAGING Indicates that bp is being used by the paging system or 178 * some paging system and that the bp is not linked into 179 * the b_vp's clean/dirty linked lists or ref counts. 180 * Buffer vp reassignments are illegal in this case. 181 * 182 * B_CACHE This may only be set if the buffer is entirely valid. 183 * The situation where B_DELWRI is set and B_CACHE is 184 * clear MUST be committed to disk by getblk() so 185 * B_DELWRI can also be cleared. See the comments for 186 * getblk() in kern/vfs_bio.c. If B_CACHE is clear, 187 * the caller is expected to clear B_ERROR|B_INVAL, 188 * set B_READ, and initiate an I/O. 189 * 190 * The 'entire buffer' is defined to be the range from 191 * 0 through b_bcount. 192 * 193 * B_MALLOC Request that the buffer be allocated from the malloc 194 * pool, DEV_BSIZE aligned instead of PAGE_SIZE aligned. 195 * 196 * B_CLUSTEROK This flag is typically set for B_DELWRI buffers 197 * by filesystems that allow clustering when the buffer 198 * is fully dirty and indicates that it may be clustered 199 * with other adjacent dirty buffers. Note the clustering 200 * may not be used with the stage 1 data write under NFS 201 * but may be used for the commit rpc portion. 202 * 203 * B_VMIO Indicates that the buffer is tied into an VM object. 204 * The buffer's data is always PAGE_SIZE aligned even 205 * if b_bufsize and b_bcount are not. ( b_bufsize is 206 * always at least DEV_BSIZE aligned, though ). 207 * 208 * B_DIRECT Hint that we should attempt to completely free 209 * the pages underlying the buffer. B_DIRECT is 210 * sticky until the buffer is released and typically 211 * only has an effect when B_RELBUF is also set. 212 * 213 * B_NOWDRAIN This flag should be set when a device (like VN) 214 * does a turn-around VOP_WRITE from its strategy 215 * routine. This flag prevents bwrite() from blocking 216 * in wdrain, avoiding a deadlock situation. 217 */ 218 219 #define B_AGE 0x00000001 /* Move to age queue when I/O done. */ 220 #define B_NEEDCOMMIT 0x00000002 /* Append-write in progress. */ 221 #define B_ASYNC 0x00000004 /* Start I/O, do not wait. */ 222 #define B_DIRECT 0x00000008 /* direct I/O flag (pls free vmio) */ 223 #define B_DEFERRED 0x00000010 /* Skipped over for cleaning */ 224 #define B_CACHE 0x00000020 /* Bread found us in the cache. */ 225 #define B_CALL 0x00000040 /* Call b_iodone from biodone. */ 226 #define B_DELWRI 0x00000080 /* Delay I/O until buffer reused. */ 227 #define B_FREEBUF 0x00000100 /* Instruct driver: free blocks */ 228 #define B_DONE 0x00000200 /* I/O completed. */ 229 #define B_EINTR 0x00000400 /* I/O was interrupted */ 230 #define B_ERROR 0x00000800 /* I/O error occurred. */ 231 #define B_UNUSED1000 0x00001000 232 #define B_INVAL 0x00002000 /* Does not contain valid info. */ 233 #define B_LOCKED 0x00004000 /* Locked in core (not reusable). */ 234 #define B_NOCACHE 0x00008000 /* Do not cache block after use. */ 235 #define B_MALLOC 0x00010000 /* malloced b_data */ 236 #define B_CLUSTEROK 0x00020000 /* Pagein op, so swap() can count it. */ 237 #define B_PHYS 0x00040000 /* I/O to user memory. */ 238 #define B_RAW 0x00080000 /* Set by physio for raw transfers. */ 239 #define B_READ 0x00100000 /* Read buffer. */ 240 #define B_DIRTY 0x00200000 /* Needs writing later. */ 241 #define B_RELBUF 0x00400000 /* Release VMIO buffer. */ 242 #define B_WANT 0x00800000 /* Used by vm_pager.c */ 243 #define B_WRITE 0x00000000 /* Write buffer (pseudo flag). */ 244 #define B_UNUSED1000000 0x01000000 245 #define B_XXX 0x02000000 /* Debugging flag. */ 246 #define B_PAGING 0x04000000 /* volatile paging I/O -- bypass VMIO */ 247 #define B_ORDERED 0x08000000 /* Must guarantee I/O ordering */ 248 #define B_RAM 0x10000000 /* Read ahead mark (flag) */ 249 #define B_VMIO 0x20000000 /* VMIO flag */ 250 #define B_CLUSTER 0x40000000 /* pagein op, so swap() can count it */ 251 #define B_NOWDRAIN 0x80000000 /* Avoid wdrain deadlock */ 252 253 #define PRINT_BUF_FLAGS "\20\40nowdrain\37cluster\36vmio\35ram\34ordered" \ 254 "\33paging\32xxx\31writeinprog\30want\27relbuf\26dirty" \ 255 "\25read\24raw\23phys\22clusterok\21malloc\20nocache" \ 256 "\17locked\16inval\15scanned\14error\13eintr\12done\11freebuf" \ 257 "\10delwri\7call\6cache\4direct\3async\2needcommit\1age" 258 259 /* 260 * These flags are kept in b_xflags. 261 */ 262 #define BX_VNDIRTY 0x00000001 /* On vnode dirty list */ 263 #define BX_VNCLEAN 0x00000002 /* On vnode clean list */ 264 #define BX_BKGRDWRITE 0x00000004 /* Do writes in background */ 265 #define BX_BKGRDINPROG 0x00000008 /* Background write in progress */ 266 #define BX_BKGRDWAIT 0x00000010 /* Background write waiting */ 267 #define BX_AUTOCHAINDONE 0x00000020 /* pager I/O chain auto mode */ 268 269 #define NOOFFSET (-1LL) /* No buffer offset calculated yet */ 270 271 #ifdef _KERNEL 272 /* 273 * Buffer locking. See sys/buf2.h for inline functions. 274 */ 275 extern struct lwkt_token buftimetoken; /* Interlock on setting prio and timo */ 276 extern char *buf_wmesg; /* Default buffer lock message */ 277 #define BUF_WMESG "bufwait" 278 279 #endif /* _KERNEL */ 280 281 struct buf_queue_head { 282 TAILQ_HEAD(buf_queue, buf) queue; 283 daddr_t last_pblkno; 284 struct buf *insert_point; 285 struct buf *switch_point; 286 }; 287 288 /* 289 * This structure describes a clustered I/O. It is stored in the b_saveaddr 290 * field of the buffer on which I/O is done. At I/O completion, cluster 291 * callback uses the structure to parcel I/O's to individual buffers, and 292 * then free's this structure. 293 */ 294 struct cluster_save { 295 long bs_bcount; /* Saved b_bcount. */ 296 long bs_bufsize; /* Saved b_bufsize. */ 297 void *bs_saveaddr; /* Saved b_addr. */ 298 int bs_nchildren; /* Number of associated buffers. */ 299 struct buf **bs_children; /* List of associated buffers. */ 300 }; 301 302 /* 303 * Definitions for the buffer free lists. 304 */ 305 #define BUFFER_QUEUES 6 /* number of free buffer queues */ 306 307 #define QUEUE_NONE 0 /* on no queue */ 308 #define QUEUE_LOCKED 1 /* locked buffers */ 309 #define QUEUE_CLEAN 2 /* non-B_DELWRI buffers */ 310 #define QUEUE_DIRTY 3 /* B_DELWRI buffers */ 311 #define QUEUE_EMPTYKVA 4 /* empty buffer headers w/KVA assignment */ 312 #define QUEUE_EMPTY 5 /* empty buffer headers */ 313 314 /* 315 * Zero out the buffer's data area. 316 */ 317 #define clrbuf(bp) { \ 318 bzero((bp)->b_data, (u_int)(bp)->b_bcount); \ 319 (bp)->b_resid = 0; \ 320 } 321 322 /* 323 * Flags to low-level bitmap allocation routines (balloc). 324 * 325 * Note: sequential_heuristic() in kern/vfs_vnops.c limits the count 326 * to 127. 327 */ 328 #define B_SEQMASK 0x7F000000 /* Sequential heuristic mask. */ 329 #define B_SEQSHIFT 24 /* Sequential heuristic shift. */ 330 #define B_SEQMAX 0x7F 331 #define B_CLRBUF 0x01 /* Cleared invalid areas of buffer. */ 332 #define B_SYNC 0x02 /* Do all allocations synchronously. */ 333 334 #ifdef _KERNEL 335 extern int nbuf; /* The number of buffer headers */ 336 extern int maxswzone; /* Max KVA for swap structures */ 337 extern int maxbcache; /* Max KVA for buffer cache */ 338 extern int runningbufspace; 339 extern int buf_maxio; /* nominal maximum I/O for buffer */ 340 extern struct buf *buf; /* The buffer headers. */ 341 extern char *buffers; /* The buffer contents. */ 342 extern int bufpages; /* Number of memory pages in the buffer pool. */ 343 extern struct buf *swbuf; /* Swap I/O buffer headers. */ 344 extern int nswbuf; /* Number of swap I/O buffer headers. */ 345 extern TAILQ_HEAD(swqueue, buf) bswlist; 346 extern TAILQ_HEAD(bqueues, buf) bufqueues[BUFFER_QUEUES]; 347 348 struct uio; 349 350 caddr_t bufhashinit (caddr_t); 351 void bufinit (void); 352 void bwillwrite (void); 353 int buf_dirty_count_severe (void); 354 void bremfree (struct buf *); 355 int bread (struct vnode *, daddr_t, int, struct buf **); 356 int breadn (struct vnode *, daddr_t, int, daddr_t *, int *, int, 357 struct buf **); 358 int bwrite (struct buf *); 359 void bdwrite (struct buf *); 360 void bawrite (struct buf *); 361 void bdirty (struct buf *); 362 void bundirty (struct buf *); 363 int bowrite (struct buf *); 364 void brelse (struct buf *); 365 void bqrelse (struct buf *); 366 int vfs_bio_awrite (struct buf *); 367 struct buf * getpbuf (int *); 368 struct buf *incore (struct vnode *, daddr_t); 369 struct buf *gbincore (struct vnode *, daddr_t); 370 int inmem (struct vnode *, daddr_t); 371 struct buf *getblk (struct vnode *, daddr_t, int, int, int); 372 struct buf *geteblk (int); 373 int biowait (struct buf *); 374 void biodone (struct buf *); 375 376 void cluster_callback (struct buf *); 377 int cluster_read (struct vnode *, u_quad_t, daddr_t, long, 378 long, int, struct buf **); 379 int cluster_wbuild (struct vnode *, long, daddr_t, int); 380 void cluster_write (struct buf *, u_quad_t, int); 381 int physio (dev_t dev, struct uio *uio, int ioflag); 382 #define physread physio 383 #define physwrite physio 384 void vfs_bio_set_validclean (struct buf *, int base, int size); 385 void vfs_bio_clrbuf (struct buf *); 386 void vfs_busy_pages (struct buf *, int clear_modify); 387 void vfs_unbusy_pages (struct buf *); 388 void vwakeup (struct buf *); 389 int vmapbuf (struct buf *); 390 void vunmapbuf (struct buf *); 391 void relpbuf (struct buf *, int *); 392 void brelvp (struct buf *); 393 void bgetvp (struct vnode *, struct buf *); 394 void pbgetvp (struct vnode *, struct buf *); 395 void pbrelvp (struct buf *); 396 int allocbuf (struct buf *bp, int size); 397 void reassignbuf (struct buf *, struct vnode *); 398 void pbreassignbuf (struct buf *, struct vnode *); 399 struct buf *trypbuf (int *); 400 401 #endif /* _KERNEL */ 402 403 #endif /* !_SYS_BUF_H_ */ 404