/* * Copyright (c) 1982, 1986, 1989, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)buf.h 8.9 (Berkeley) 3/30/95 * $FreeBSD: src/sys/sys/buf.h,v 1.88.2.10 2003/01/25 19:02:23 dillon Exp $ * $DragonFly: src/sys/sys/buf.h,v 1.11 2004/07/17 01:45:37 hmp Exp $ */ #ifndef _SYS_BUF_H_ #define _SYS_BUF_H_ #ifndef _SYS_QUEUE_H_ #include #endif #ifndef _SYS_LOCK_H_ #include #endif #ifndef _SYS_DEVICE_H_ #include #endif #ifndef _SYS_XIO_H_ #include #endif struct buf; struct mount; struct vnode; struct xio; /* * To avoid including */ LIST_HEAD(workhead, worklist); /* * These are currently used only by the soft dependency code, hence * are stored once in a global variable. If other subsystems wanted * to use these hooks, a pointer to a set of bio_ops could be added * to each buffer. */ extern struct bio_ops { void (*io_start) (struct buf *); void (*io_complete) (struct buf *); void (*io_deallocate) (struct buf *); int (*io_fsync) (struct vnode *); int (*io_sync) (struct mount *); void (*io_movedeps) (struct buf *, struct buf *); int (*io_countdeps) (struct buf *, int); } bioops; struct iodone_chain { long ic_prev_flags; void (*ic_prev_iodone) (struct buf *); void *ic_prev_iodone_chain; struct { long ia_long; void *ia_ptr; } ic_args[5]; }; /* * The buffer header describes an I/O operation in the kernel. * * NOTES: * b_bufsize, b_bcount. b_bufsize is the allocation size of the * buffer, either DEV_BSIZE or PAGE_SIZE aligned. b_bcount is the * originally requested buffer size and can serve as a bounds check * against EOF. For most, but not all uses, b_bcount == b_bufsize. * * b_dirtyoff, b_dirtyend. Buffers support piecemeal, unaligned * ranges of dirty data that need to be written to backing store. * The range is typically clipped at b_bcount ( not b_bufsize ). * * b_resid. Number of bytes remaining in I/O. After an I/O operation * completes, b_resid is usually 0 indicating 100% success. */ struct buf { LIST_ENTRY(buf) b_hash; /* Hash chain. */ TAILQ_ENTRY(buf) b_vnbufs; /* Buffer's associated vnode. */ TAILQ_ENTRY(buf) b_freelist; /* Free list position if not active. */ TAILQ_ENTRY(buf) b_act; /* Device driver queue when active. *new* */ long b_flags; /* B_* flags. */ unsigned short b_qindex; /* buffer queue index */ unsigned char b_xflags; /* extra flags */ struct lock b_lock; /* Buffer lock */ int b_error; /* Errno value. */ long b_bufsize; /* Allocated buffer size. */ long b_runningbufspace; /* when I/O is running, pipelining */ long b_bcount; /* Valid bytes in buffer. */ long b_resid; /* Remaining I/O. */ dev_t b_dev; /* Device associated with buffer. */ caddr_t b_data; /* Memory, superblocks, indirect etc. */ caddr_t b_kvabase; /* base kva for buffer */ int b_kvasize; /* size of kva for buffer */ daddr_t b_lblkno; /* Logical block number. */ daddr_t b_blkno; /* Underlying physical block number. */ off_t b_offset; /* Offset into file */ /* Function to call upon completion. */ void (*b_iodone) (struct buf *); /* For nested b_iodone's. */ struct iodone_chain *b_iodone_chain; struct vnode *b_vp; /* Device vnode. */ int b_dirtyoff; /* Offset in buffer of dirty region. */ int b_dirtyend; /* Offset of end of dirty region. */ daddr_t b_pblkno; /* physical block number */ void *b_saveaddr; /* Original b_addr for physio. */ void *b_driver1; /* for private use by the driver */ void *b_caller1; /* for private use by the caller */ union pager_info { void *pg_spc; int pg_reqpage; } b_pager; union cluster_info { TAILQ_HEAD(cluster_list_head, buf) cluster_head; TAILQ_ENTRY(buf) cluster_entry; } b_cluster; struct xio b_xio; /* page list management for buffer head. */ struct workhead b_dep; /* List of filesystem dependencies. */ struct chain_info { /* buffer chaining */ struct buf *parent; int count; } b_chain; }; #define b_spc b_pager.pg_spc /* * These flags are kept in b_flags. * * Notes: * * B_ASYNC VOP calls on bp's are usually async whether or not * B_ASYNC is set, but some subsystems, such as NFS, like * to know what is best for the caller so they can * optimize the I/O. * * B_PAGING Indicates that bp is being used by the paging system or * some paging system and that the bp is not linked into * the b_vp's clean/dirty linked lists or ref counts. * Buffer vp reassignments are illegal in this case. * * B_CACHE This may only be set if the buffer is entirely valid. * The situation where B_DELWRI is set and B_CACHE is * clear MUST be committed to disk by getblk() so * B_DELWRI can also be cleared. See the comments for * getblk() in kern/vfs_bio.c. If B_CACHE is clear, * the caller is expected to clear B_ERROR|B_INVAL, * set B_READ, and initiate an I/O. * * The 'entire buffer' is defined to be the range from * 0 through b_bcount. * * B_MALLOC Request that the buffer be allocated from the malloc * pool, DEV_BSIZE aligned instead of PAGE_SIZE aligned. * * B_CLUSTEROK This flag is typically set for B_DELWRI buffers * by filesystems that allow clustering when the buffer * is fully dirty and indicates that it may be clustered * with other adjacent dirty buffers. Note the clustering * may not be used with the stage 1 data write under NFS * but may be used for the commit rpc portion. * * B_VMIO Indicates that the buffer is tied into an VM object. * The buffer's data is always PAGE_SIZE aligned even * if b_bufsize and b_bcount are not. ( b_bufsize is * always at least DEV_BSIZE aligned, though ). * * B_DIRECT Hint that we should attempt to completely free * the pages underlying the buffer. B_DIRECT is * sticky until the buffer is released and typically * only has an effect when B_RELBUF is also set. * * B_NOWDRAIN This flag should be set when a device (like VN) * does a turn-around VOP_WRITE from its strategy * routine. This flag prevents bwrite() from blocking * in wdrain, avoiding a deadlock situation. */ #define B_AGE 0x00000001 /* Move to age queue when I/O done. */ #define B_NEEDCOMMIT 0x00000002 /* Append-write in progress. */ #define B_ASYNC 0x00000004 /* Start I/O, do not wait. */ #define B_DIRECT 0x00000008 /* direct I/O flag (pls free vmio) */ #define B_DEFERRED 0x00000010 /* Skipped over for cleaning */ #define B_CACHE 0x00000020 /* Bread found us in the cache. */ #define B_CALL 0x00000040 /* Call b_iodone from biodone. */ #define B_DELWRI 0x00000080 /* Delay I/O until buffer reused. */ #define B_FREEBUF 0x00000100 /* Instruct driver: free blocks */ #define B_DONE 0x00000200 /* I/O completed. */ #define B_EINTR 0x00000400 /* I/O was interrupted */ #define B_ERROR 0x00000800 /* I/O error occurred. */ #define B_SCANNED 0x00001000 /* VOP_FSYNC funcs mark written bufs */ #define B_INVAL 0x00002000 /* Does not contain valid info. */ #define B_LOCKED 0x00004000 /* Locked in core (not reusable). */ #define B_NOCACHE 0x00008000 /* Do not cache block after use. */ #define B_MALLOC 0x00010000 /* malloced b_data */ #define B_CLUSTEROK 0x00020000 /* Pagein op, so swap() can count it. */ #define B_PHYS 0x00040000 /* I/O to user memory. */ #define B_RAW 0x00080000 /* Set by physio for raw transfers. */ #define B_READ 0x00100000 /* Read buffer. */ #define B_DIRTY 0x00200000 /* Needs writing later. */ #define B_RELBUF 0x00400000 /* Release VMIO buffer. */ #define B_WANT 0x00800000 /* Used by vm_pager.c */ #define B_WRITE 0x00000000 /* Write buffer (pseudo flag). */ #define B_WRITEINPROG 0x01000000 /* Write in progress. */ #define B_XXX 0x02000000 /* Debugging flag. */ #define B_PAGING 0x04000000 /* volatile paging I/O -- bypass VMIO */ #define B_ORDERED 0x08000000 /* Must guarantee I/O ordering */ #define B_RAM 0x10000000 /* Read ahead mark (flag) */ #define B_VMIO 0x20000000 /* VMIO flag */ #define B_CLUSTER 0x40000000 /* pagein op, so swap() can count it */ #define B_NOWDRAIN 0x80000000 /* Avoid wdrain deadlock */ #define PRINT_BUF_FLAGS "\20\40nowdrain\37cluster\36vmio\35ram\34ordered" \ "\33paging\32xxx\31writeinprog\30want\27relbuf\26dirty" \ "\25read\24raw\23phys\22clusterok\21malloc\20nocache" \ "\17locked\16inval\15scanned\14error\13eintr\12done\11freebuf" \ "\10delwri\7call\6cache\4direct\3async\2needcommit\1age" /* * These flags are kept in b_xflags. */ #define BX_VNDIRTY 0x00000001 /* On vnode dirty list */ #define BX_VNCLEAN 0x00000002 /* On vnode clean list */ #define BX_BKGRDWRITE 0x00000004 /* Do writes in background */ #define BX_BKGRDINPROG 0x00000008 /* Background write in progress */ #define BX_BKGRDWAIT 0x00000010 /* Background write waiting */ #define BX_AUTOCHAINDONE 0x00000020 /* pager I/O chain auto mode */ #define NOOFFSET (-1LL) /* No buffer offset calculated yet */ #ifdef _KERNEL /* * Buffer locking. See sys/buf2.h for inline functions. */ extern struct lwkt_token buftimetoken; /* Interlock on setting prio and timo */ extern char *buf_wmesg; /* Default buffer lock message */ #define BUF_WMESG "bufwait" #endif /* _KERNEL */ struct buf_queue_head { TAILQ_HEAD(buf_queue, buf) queue; daddr_t last_pblkno; struct buf *insert_point; struct buf *switch_point; }; /* * This structure describes a clustered I/O. It is stored in the b_saveaddr * field of the buffer on which I/O is done. At I/O completion, cluster * callback uses the structure to parcel I/O's to individual buffers, and * then free's this structure. */ struct cluster_save { long bs_bcount; /* Saved b_bcount. */ long bs_bufsize; /* Saved b_bufsize. */ void *bs_saveaddr; /* Saved b_addr. */ int bs_nchildren; /* Number of associated buffers. */ struct buf **bs_children; /* List of associated buffers. */ }; /* * Definitions for the buffer free lists. */ #define BUFFER_QUEUES 6 /* number of free buffer queues */ #define QUEUE_NONE 0 /* on no queue */ #define QUEUE_LOCKED 1 /* locked buffers */ #define QUEUE_CLEAN 2 /* non-B_DELWRI buffers */ #define QUEUE_DIRTY 3 /* B_DELWRI buffers */ #define QUEUE_EMPTYKVA 4 /* empty buffer headers w/KVA assignment */ #define QUEUE_EMPTY 5 /* empty buffer headers */ /* * Zero out the buffer's data area. */ #define clrbuf(bp) { \ bzero((bp)->b_data, (u_int)(bp)->b_bcount); \ (bp)->b_resid = 0; \ } /* * Flags to low-level bitmap allocation routines (balloc). * * Note: sequential_heuristic() in kern/vfs_vnops.c limits the count * to 127. */ #define B_SEQMASK 0x7F000000 /* Sequential heuristic mask. */ #define B_SEQSHIFT 24 /* Sequential heuristic shift. */ #define B_SEQMAX 0x7F #define B_CLRBUF 0x01 /* Cleared invalid areas of buffer. */ #define B_SYNC 0x02 /* Do all allocations synchronously. */ #ifdef _KERNEL extern int nbuf; /* The number of buffer headers */ extern int maxswzone; /* Max KVA for swap structures */ extern int maxbcache; /* Max KVA for buffer cache */ extern int runningbufspace; extern int buf_maxio; /* nominal maximum I/O for buffer */ extern struct buf *buf; /* The buffer headers. */ extern char *buffers; /* The buffer contents. */ extern int bufpages; /* Number of memory pages in the buffer pool. */ extern struct buf *swbuf; /* Swap I/O buffer headers. */ extern int nswbuf; /* Number of swap I/O buffer headers. */ extern TAILQ_HEAD(swqueue, buf) bswlist; extern TAILQ_HEAD(bqueues, buf) bufqueues[BUFFER_QUEUES]; struct uio; caddr_t bufhashinit (caddr_t); void bufinit (void); void bwillwrite (void); int buf_dirty_count_severe (void); void bremfree (struct buf *); int bread (struct vnode *, daddr_t, int, struct buf **); int breadn (struct vnode *, daddr_t, int, daddr_t *, int *, int, struct buf **); int bwrite (struct buf *); void bdwrite (struct buf *); void bawrite (struct buf *); void bdirty (struct buf *); void bundirty (struct buf *); int bowrite (struct buf *); void brelse (struct buf *); void bqrelse (struct buf *); int vfs_bio_awrite (struct buf *); struct buf * getpbuf (int *); struct buf *incore (struct vnode *, daddr_t); struct buf *gbincore (struct vnode *, daddr_t); int inmem (struct vnode *, daddr_t); struct buf *getblk (struct vnode *, daddr_t, int, int, int); struct buf *geteblk (int); int biowait (struct buf *); void biodone (struct buf *); void cluster_callback (struct buf *); int cluster_read (struct vnode *, u_quad_t, daddr_t, long, long, int, struct buf **); int cluster_wbuild (struct vnode *, long, daddr_t, int); void cluster_write (struct buf *, u_quad_t, int); int physio (dev_t dev, struct uio *uio, int ioflag); #define physread physio #define physwrite physio void vfs_bio_set_validclean (struct buf *, int base, int size); void vfs_bio_clrbuf (struct buf *); void vfs_busy_pages (struct buf *, int clear_modify); void vfs_unbusy_pages (struct buf *); void vwakeup (struct buf *); int vmapbuf (struct buf *); void vunmapbuf (struct buf *); void relpbuf (struct buf *, int *); void brelvp (struct buf *); void bgetvp (struct vnode *, struct buf *); void pbgetvp (struct vnode *, struct buf *); void pbrelvp (struct buf *); int allocbuf (struct buf *bp, int size); void reassignbuf (struct buf *, struct vnode *); void pbreassignbuf (struct buf *, struct vnode *); struct buf *trypbuf (int *); #endif /* _KERNEL */ #endif /* !_SYS_BUF_H_ */