1 /* 2 * Copyright (c) 1982, 1986, 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 * 7 * @(#)buf.h 8.6 (Berkeley) 01/06/94 8 */ 9 10 #ifndef _SYS_BUF_H_ 11 #define _SYS_BUF_H_ 12 #include <sys/queue.h> 13 14 #define NOLIST ((struct buf *)0x87654321) 15 16 /* 17 * The buffer header describes an I/O operation in the kernel. 18 */ 19 struct buf { 20 LIST_ENTRY(buf) b_hash; /* Hash chain. */ 21 LIST_ENTRY(buf) b_vnbufs; /* Buffer's associated vnode. */ 22 TAILQ_ENTRY(buf) b_freelist; /* Free list position if not active. */ 23 struct buf *b_actf, **b_actb; /* Device driver queue when active. */ 24 struct proc *b_proc; /* Associated proc; NULL if kernel. */ 25 volatile long b_flags; /* B_* flags. */ 26 int b_error; /* Errno value. */ 27 long b_bufsize; /* Allocated buffer size. */ 28 long b_bcount; /* Valid bytes in buffer. */ 29 long b_resid; /* Remaining I/O. */ 30 dev_t b_dev; /* Device associated with buffer. */ 31 struct { 32 caddr_t b_addr; /* Memory, superblocks, indirect etc. */ 33 } b_un; 34 void *b_saveaddr; /* Original b_addr for physio. */ 35 daddr_t b_lblkno; /* Logical block number. */ 36 daddr_t b_blkno; /* Underlying physical block number. */ 37 /* Function to call upon completion. */ 38 void (*b_iodone) __P((struct buf *)); 39 struct vnode *b_vp; /* Device vnode. */ 40 int b_pfcent; /* Center page when swapping cluster. */ 41 int b_dirtyoff; /* Offset in buffer of dirty region. */ 42 int b_dirtyend; /* Offset of end of dirty region. */ 43 struct ucred *b_rcred; /* Read credentials reference. */ 44 struct ucred *b_wcred; /* Write credentials reference. */ 45 int b_validoff; /* Offset in buffer of valid region. */ 46 int b_validend; /* Offset of end of valid region. */ 47 }; 48 49 /* Device driver compatibility definitions. */ 50 #define b_active b_bcount /* Driver queue head: drive active. */ 51 #define b_data b_un.b_addr /* b_un.b_addr is not changeable. */ 52 #define b_errcnt b_resid /* Retry count while I/O in progress. */ 53 #define iodone biodone /* Old name for biodone. */ 54 #define iowait biowait /* Old name for biowait. */ 55 56 /* 57 * These flags are kept in b_flags. 58 */ 59 #define B_AGE 0x00000001 /* Move to age queue when I/O done. */ 60 #define B_APPENDWRITE 0x00000002 /* Append-write in progress. */ 61 #define B_ASYNC 0x00000004 /* Start I/O, do not wait. */ 62 #define B_BAD 0x00000008 /* Bad block revectoring in progress. */ 63 #define B_BUSY 0x00000010 /* I/O in progress. */ 64 #define B_CACHE 0x00000020 /* Bread found us in the cache. */ 65 #define B_CALL 0x00000040 /* Call b_iodone from biodone. */ 66 #define B_DELWRI 0x00000080 /* Delay I/O until buffer reused. */ 67 #define B_DIRTY 0x00000100 /* Dirty page to be pushed out async. */ 68 #define B_DONE 0x00000200 /* I/O completed. */ 69 #define B_EINTR 0x00000400 /* I/O was interrupted */ 70 #define B_ERROR 0x00000800 /* I/O error occurred. */ 71 #define B_GATHERED 0x00001000 /* LFS: already in a segment. */ 72 #define B_INVAL 0x00002000 /* Does not contain valid info. */ 73 #define B_LOCKED 0x00004000 /* Locked in core (not reusable). */ 74 #define B_NOCACHE 0x00008000 /* Do not cache block after use. */ 75 #define B_PAGET 0x00010000 /* Page in/out of page table space. */ 76 #define B_PGIN 0x00020000 /* Pagein op, so swap() can count it. */ 77 #define B_PHYS 0x00040000 /* I/O to user memory. */ 78 #define B_RAW 0x00080000 /* Set by physio for raw transfers. */ 79 #define B_READ 0x00100000 /* Read buffer. */ 80 #define B_TAPE 0x00200000 /* Magnetic tape I/O. */ 81 #define B_UAREA 0x00400000 /* Buffer describes Uarea I/O. */ 82 #define B_WANTED 0x00800000 /* Process wants this buffer. */ 83 #define B_WRITE 0x00000000 /* Write buffer (pseudo flag). */ 84 #define B_WRITEINPROG 0x01000000 /* Write in progress. */ 85 #define B_XXX 0x02000000 /* Debugging flag. */ 86 87 /* 88 * This structure describes a clustered I/O. It is stored in the b_saveaddr 89 * field of the buffer on which I/O is done. At I/O completion, cluster 90 * callback uses the structure to parcel I/O's to individual buffers, and 91 * then free's this structure. 92 */ 93 struct cluster_save { 94 long bs_bcount; /* Saved b_bcount. */ 95 long bs_bufsize; /* Saved b_bufsize. */ 96 void *bs_saveaddr; /* Saved b_addr. */ 97 int bs_nchildren; /* Number of associated buffers. */ 98 struct buf **bs_children; /* List of associated buffers. */ 99 }; 100 101 /* 102 * Zero out the buffer's data area. 103 */ 104 #define clrbuf(bp) { \ 105 blkclr((bp)->b_data, (u_int)(bp)->b_bcount); \ 106 (bp)->b_resid = 0; \ 107 } 108 109 /* Flags to low-level allocation routines. */ 110 #define B_CLRBUF 0x01 /* Request allocated buffer be cleared. */ 111 #define B_SYNC 0x02 /* Do all allocations synchronously. */ 112 113 #ifdef KERNEL 114 int nbuf; /* The number of buffer headers */ 115 struct buf *buf; /* The buffer headers. */ 116 char *buffers; /* The buffer contents. */ 117 int bufpages; /* Number of memory pages in the buffer pool. */ 118 struct buf *swbuf; /* Swap I/O buffer headers. */ 119 int nswbuf; /* Number of swap I/O buffer headers. */ 120 struct buf bswlist; /* Head of swap I/O buffer headers free list. */ 121 struct buf *bclnlist; /* Head of cleaned page list. */ 122 123 __BEGIN_DECLS 124 int allocbuf __P((struct buf *, int)); 125 int bawrite __P((struct buf *)); 126 int bdwrite __P((struct buf *)); 127 void biodone __P((struct buf *)); 128 int biowait __P((struct buf *)); 129 int bread __P((struct vnode *, daddr_t, int, 130 struct ucred *, struct buf **)); 131 int breadn __P((struct vnode *, daddr_t, int, daddr_t *, int *, int, 132 struct ucred *, struct buf **)); 133 int brelse __P((struct buf *)); 134 void bufinit __P((void)); 135 int bwrite __P((struct buf *)); 136 void cluster_callback __P((struct buf *)); 137 int cluster_read __P((struct vnode *, u_quad_t, daddr_t, long, 138 struct ucred *, struct buf **)); 139 void cluster_write __P((struct buf *, u_quad_t)); 140 struct buf *getblk __P((struct vnode *, daddr_t, int, int, int)); 141 struct buf *geteblk __P((int)); 142 struct buf *getnewbuf __P((int slpflag, int slptimeo)); 143 struct buf *incore __P((struct vnode *, daddr_t)); 144 u_int minphys __P((struct buf *bp)); 145 __END_DECLS 146 #endif 147 #endif /* !_SYS_BUF_H_ */ 148