507 lines
17 KiB
C
507 lines
17 KiB
C
/*
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)buf.h 8.9 (Berkeley) 3/30/95
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* $FreeBSD$
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*/
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#ifndef _SYS_BUF_H_
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#define _SYS_BUF_H_
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#include <sys/queue.h>
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#include <sys/lock.h>
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#include <sys/lockmgr.h>
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struct bio;
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struct buf;
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struct mount;
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struct vnode;
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/*
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* To avoid including <ufs/ffs/softdep.h>
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*/
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LIST_HEAD(workhead, worklist);
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/*
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* These are currently used only by the soft dependency code, hence
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* are stored once in a global variable. If other subsystems wanted
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* to use these hooks, a pointer to a set of bio_ops could be added
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* to each buffer.
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*/
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extern struct bio_ops {
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void (*io_start)(struct buf *);
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void (*io_complete)(struct buf *);
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void (*io_deallocate)(struct buf *);
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void (*io_movedeps)(struct buf *, struct buf *);
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int (*io_countdeps)(struct buf *, int);
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} bioops;
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struct buf_ops {
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char *bop_name;
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int (*bop_write)(struct buf *);
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};
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extern struct buf_ops buf_ops_bio;
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/*
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* The buffer header describes an I/O operation in the kernel.
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*
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* NOTES:
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* b_bufsize, b_bcount. b_bufsize is the allocation size of the
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* buffer, either DEV_BSIZE or PAGE_SIZE aligned. b_bcount is the
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* originally requested buffer size and can serve as a bounds check
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* against EOF. For most, but not all uses, b_bcount == b_bufsize.
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*
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* b_dirtyoff, b_dirtyend. Buffers support piecemeal, unaligned
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* ranges of dirty data that need to be written to backing store.
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* The range is typically clipped at b_bcount ( not b_bufsize ).
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*
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* b_resid. Number of bytes remaining in I/O. After an I/O operation
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* completes, b_resid is usually 0 indicating 100% success.
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*/
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struct buf {
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/* XXX: b_io must be the first element of struct buf for now /phk */
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/* XXX: if you change this, fix BIOTOBUF macro below */
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struct bio b_io; /* "Builtin" I/O request. */
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#define BIOTOBUF(biop) ((struct buf *)(biop))
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#define b_bcount b_io.bio_bcount
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#define b_blkno b_io.bio_blkno
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#define b_caller1 b_io.bio_caller1
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#define b_data b_io.bio_data
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#define b_dev b_io.bio_dev
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#define b_driver1 b_io.bio_driver1
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#define b_driver2 b_io.bio_driver2
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#define b_error b_io.bio_error
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#define b_iocmd b_io.bio_cmd
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#define b_ioflags b_io.bio_flags
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#define b_pblkno b_io.bio_pblkno
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#define b_resid b_io.bio_resid
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struct buf_ops *b_op;
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unsigned b_magic;
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#define B_MAGIC_BIO 0x10b10b10
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#define B_MAGIC_NFS 0x67238234
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void (*b_iodone)(struct buf *);
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off_t b_offset; /* Offset into file. */
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LIST_ENTRY(buf) b_hash; /* Hash chain. */
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TAILQ_ENTRY(buf) b_vnbufs; /* Buffer's associated vnode. */
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TAILQ_ENTRY(buf) b_freelist; /* Free list position if not active. */
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long b_flags; /* B_* flags. */
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unsigned short b_qindex; /* buffer queue index */
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unsigned char b_xflags; /* extra flags */
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struct lock b_lock; /* Buffer lock */
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long b_bufsize; /* Allocated buffer size. */
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long b_runningbufspace; /* when I/O is running, pipelining */
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caddr_t b_kvabase; /* base kva for buffer */
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int b_kvasize; /* size of kva for buffer */
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daddr_t b_lblkno; /* Logical block number. */
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struct vnode *b_vp; /* Device vnode. */
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int b_dirtyoff; /* Offset in buffer of dirty region. */
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int b_dirtyend; /* Offset of end of dirty region. */
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struct ucred *b_rcred; /* Read credentials reference. */
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struct ucred *b_wcred; /* Write credentials reference. */
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void *b_saveaddr; /* Original b_addr for physio. */
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union pager_info {
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void *pg_spc;
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int pg_reqpage;
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} b_pager;
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union cluster_info {
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TAILQ_HEAD(cluster_list_head, buf) cluster_head;
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TAILQ_ENTRY(buf) cluster_entry;
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} b_cluster;
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struct vm_page *b_pages[btoc(MAXPHYS)];
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int b_npages;
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struct workhead b_dep; /* List of filesystem dependencies. */
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};
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#define b_spc b_pager.pg_spc
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/*
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* These flags are kept in b_flags.
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*
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* Notes:
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*
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* B_ASYNC VOP calls on bp's are usually async whether or not
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* B_ASYNC is set, but some subsystems, such as NFS, like
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* to know what is best for the caller so they can
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* optimize the I/O.
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*
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* B_PAGING Indicates that bp is being used by the paging system or
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* some paging system and that the bp is not linked into
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* the b_vp's clean/dirty linked lists or ref counts.
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* Buffer vp reassignments are illegal in this case.
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*
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* B_CACHE This may only be set if the buffer is entirely valid.
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* The situation where B_DELWRI is set and B_CACHE is
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* clear MUST be committed to disk by getblk() so
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* B_DELWRI can also be cleared. See the comments for
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* getblk() in kern/vfs_bio.c. If B_CACHE is clear,
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* the caller is expected to clear BIO_ERROR and B_INVAL,
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* set BIO_READ, and initiate an I/O.
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*
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* The 'entire buffer' is defined to be the range from
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* 0 through b_bcount.
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*
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* B_MALLOC Request that the buffer be allocated from the malloc
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* pool, DEV_BSIZE aligned instead of PAGE_SIZE aligned.
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*
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* B_CLUSTEROK This flag is typically set for B_DELWRI buffers
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* by filesystems that allow clustering when the buffer
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* is fully dirty and indicates that it may be clustered
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* with other adjacent dirty buffers. Note the clustering
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* may not be used with the stage 1 data write under NFS
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* but may be used for the commit rpc portion.
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*
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* B_VMIO Indicates that the buffer is tied into an VM object.
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* The buffer's data is always PAGE_SIZE aligned even
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* if b_bufsize and b_bcount are not. ( b_bufsize is
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* always at least DEV_BSIZE aligned, though ).
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*
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* B_DIRECT Hint that we should attempt to completely free
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* the pages underlying the buffer. B_DIRECT is
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* sticky until the buffer is released and typically
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* only has an effect when B_RELBUF is also set.
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*
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* B_NOWDRAIN This flag should be set when a device (like MD)
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* does a turn-around VOP_WRITE from its strategy
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* routine. This flag prevents bwrite() from blocking
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* in wdrain, avoiding a deadlock situation.
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*/
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#define B_AGE 0x00000001 /* Move to age queue when I/O done. */
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#define B_NEEDCOMMIT 0x00000002 /* Append-write in progress. */
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#define B_ASYNC 0x00000004 /* Start I/O, do not wait. */
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#define B_DIRECT 0x00000008 /* direct I/O flag (pls free vmio) */
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#define B_DEFERRED 0x00000010 /* Skipped over for cleaning */
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#define B_CACHE 0x00000020 /* Bread found us in the cache. */
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#define B_VALIDSUSPWRT 0x00000040 /* Valid write during suspension. */
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#define B_DELWRI 0x00000080 /* Delay I/O until buffer reused. */
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#define B_00000100 0x00000100 /* Available flag. */
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#define B_DONE 0x00000200 /* I/O completed. */
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#define B_EINTR 0x00000400 /* I/O was interrupted */
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#define B_NOWDRAIN 0x00000800 /* Avoid wdrain deadlock */
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#define B_SCANNED 0x00001000 /* VOP_FSYNC funcs mark written bufs */
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#define B_INVAL 0x00002000 /* Does not contain valid info. */
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#define B_LOCKED 0x00004000 /* Locked in core (not reusable). */
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#define B_NOCACHE 0x00008000 /* Do not cache block after use. */
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#define B_MALLOC 0x00010000 /* malloced b_data */
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#define B_CLUSTEROK 0x00020000 /* Pagein op, so swap() can count it. */
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#define B_PHYS 0x00040000 /* I/O to user memory. */
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#define B_00080000 0x00080000 /* Available flag. */
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#define B_00100000 0x00100000 /* Available flag. */
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#define B_DIRTY 0x00200000 /* Needs writing later (in EXT2FS). */
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#define B_RELBUF 0x00400000 /* Release VMIO buffer. */
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#define B_00800000 0x00800000 /* Available flag. */
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#define B_WRITEINPROG 0x01000000 /* Write in progress. */
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#define B_02000000 0x02000000 /* Available flag. */
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#define B_PAGING 0x04000000 /* volatile paging I/O -- bypass VMIO */
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#define B_08000000 0x08000000 /* Available flag. */
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#define B_RAM 0x10000000 /* Read ahead mark (flag) */
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#define B_VMIO 0x20000000 /* VMIO flag */
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#define B_CLUSTER 0x40000000 /* pagein op, so swap() can count it */
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#define B_80000000 0x80000000 /* Available flag. */
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#define PRINT_BUF_FLAGS "\20\40b31\37cluster\36vmio\35ram\34b27" \
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"\33paging\32b25\31writeinprog\30b23\27relbuf\26dirty\25b20" \
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"\24b19\23phys\22clusterok\21malloc\20nocache\17locked\16inval" \
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"\15scanned\14nowdrain\13eintr\12done\11b8\10delwri\7validsuspwrt" \
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"\6cache\5deferred\4direct\3async\2needcommit\1age"
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/*
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* These flags are kept in b_xflags.
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*/
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#define BX_VNDIRTY 0x00000001 /* On vnode dirty list */
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#define BX_VNCLEAN 0x00000002 /* On vnode clean list */
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#define BX_BKGRDWRITE 0x00000004 /* Do writes in background */
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#define BX_BKGRDINPROG 0x00000008 /* Background write in progress */
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#define BX_BKGRDWAIT 0x00000010 /* Background write waiting */
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#define NOOFFSET (-1LL) /* No buffer offset calculated yet */
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#ifdef _KERNEL
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/*
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* Buffer locking
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*/
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extern struct mtx buftimelock; /* Interlock on setting prio and timo */
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extern const char *buf_wmesg; /* Default buffer lock message */
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#define BUF_WMESG "bufwait"
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#include <sys/proc.h> /* XXX for curthread */
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#include <sys/mutex.h>
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/*
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* Initialize a lock.
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*/
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#define BUF_LOCKINIT(bp) \
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lockinit(&(bp)->b_lock, PRIBIO + 4, buf_wmesg, 0, 0)
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/*
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*
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* Get a lock sleeping non-interruptably until it becomes available.
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*/
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static __inline int BUF_LOCK(struct buf *, int);
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static __inline int
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BUF_LOCK(struct buf *bp, int locktype)
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{
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int s, ret;
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s = splbio();
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mtx_lock(&buftimelock);
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locktype |= LK_INTERLOCK;
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bp->b_lock.lk_wmesg = buf_wmesg;
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bp->b_lock.lk_prio = PRIBIO + 4;
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ret = lockmgr(&(bp)->b_lock, locktype, &buftimelock, curthread);
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splx(s);
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return ret;
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}
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/*
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* Get a lock sleeping with specified interruptably and timeout.
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*/
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static __inline int BUF_TIMELOCK(struct buf *, int, char *, int, int);
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static __inline int
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BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int catch, int timo)
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{
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int s, ret;
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s = splbio();
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mtx_lock(&buftimelock);
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locktype |= LK_INTERLOCK | LK_TIMELOCK;
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bp->b_lock.lk_wmesg = wmesg;
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bp->b_lock.lk_prio = (PRIBIO + 4) | catch;
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bp->b_lock.lk_timo = timo;
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ret = lockmgr(&(bp)->b_lock, (locktype), &buftimelock, curthread);
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splx(s);
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return ret;
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}
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/*
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* Release a lock. Only the acquiring process may free the lock unless
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* it has been handed off to biodone.
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*/
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static __inline void BUF_UNLOCK(struct buf *);
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static __inline void
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BUF_UNLOCK(struct buf *bp)
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{
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int s;
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s = splbio();
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lockmgr(&(bp)->b_lock, LK_RELEASE, NULL, curthread);
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splx(s);
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}
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/*
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* Free a buffer lock.
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*/
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#define BUF_LOCKFREE(bp) \
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do { \
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if (BUF_REFCNT(bp) > 0) \
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panic("free locked buf"); \
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lockdestroy(&(bp)->b_lock); \
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} while (0)
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#ifdef _SYS_PROC_H_ /* Avoid #include <sys/proc.h> pollution */
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/*
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* When initiating asynchronous I/O, change ownership of the lock to the
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* kernel. Once done, the lock may legally released by biodone. The
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* original owning process can no longer acquire it recursively, but must
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* wait until the I/O is completed and the lock has been freed by biodone.
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*/
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static __inline void BUF_KERNPROC(struct buf *);
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static __inline void
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BUF_KERNPROC(struct buf *bp)
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{
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struct thread *td = curthread;
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if ((td != PCPU_GET(idlethread))
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&& bp->b_lock.lk_lockholder == td->td_proc->p_pid)
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td->td_locks--;
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bp->b_lock.lk_lockholder = LK_KERNPROC;
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}
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#endif
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/*
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* Find out the number of references to a lock.
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*/
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static __inline int BUF_REFCNT(struct buf *);
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static __inline int
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BUF_REFCNT(struct buf *bp)
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{
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int s, ret;
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s = splbio();
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ret = lockcount(&(bp)->b_lock);
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splx(s);
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return ret;
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}
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#endif /* _KERNEL */
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struct buf_queue_head {
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TAILQ_HEAD(buf_queue, buf) queue;
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daddr_t last_pblkno;
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struct buf *insert_point;
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struct buf *switch_point;
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};
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/*
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* This structure describes a clustered I/O. It is stored in the b_saveaddr
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* field of the buffer on which I/O is done. At I/O completion, cluster
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* callback uses the structure to parcel I/O's to individual buffers, and
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* then free's this structure.
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*/
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struct cluster_save {
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long bs_bcount; /* Saved b_bcount. */
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long bs_bufsize; /* Saved b_bufsize. */
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void *bs_saveaddr; /* Saved b_addr. */
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int bs_nchildren; /* Number of associated buffers. */
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struct buf **bs_children; /* List of associated buffers. */
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};
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#ifdef _KERNEL
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#define BUF_WRITE(bp) \
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(bp)->b_op->bop_write(bp)
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#define BUF_STRATEGY(bp) VOP_STRATEGY((bp)->b_vp, (bp))
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static __inline void
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buf_start(struct buf *bp)
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{
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if (bioops.io_start)
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(*bioops.io_start)(bp);
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}
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static __inline void
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buf_complete(struct buf *bp)
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{
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if (bioops.io_complete)
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(*bioops.io_complete)(bp);
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}
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static __inline void
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buf_deallocate(struct buf *bp)
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{
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if (bioops.io_deallocate)
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(*bioops.io_deallocate)(bp);
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BUF_LOCKFREE(bp);
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}
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static __inline void
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buf_movedeps(struct buf *bp, struct buf *bp2)
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{
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if (bioops.io_movedeps)
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(*bioops.io_movedeps)(bp, bp2);
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}
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static __inline int
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buf_countdeps(struct buf *bp, int i)
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{
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if (bioops.io_countdeps)
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return ((*bioops.io_countdeps)(bp, i));
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else
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return (0);
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}
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#endif /* _KERNEL */
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/*
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* Zero out the buffer's data area.
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*/
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#define clrbuf(bp) { \
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bzero((bp)->b_data, (u_int)(bp)->b_bcount); \
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(bp)->b_resid = 0; \
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}
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#ifdef _KERNEL
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extern int nbuf; /* The number of buffer headers */
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extern int maxswzone; /* Max KVA for swap structures */
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extern int maxbcache; /* Max KVA for buffer cache */
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extern int runningbufspace;
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extern int buf_maxio; /* nominal maximum I/O for buffer */
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extern struct buf *buf; /* The buffer headers. */
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extern char *buffers; /* The buffer contents. */
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extern int bufpages; /* Number of memory pages in the buffer pool. */
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extern struct buf *swbuf; /* Swap I/O buffer headers. */
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extern int nswbuf; /* Number of swap I/O buffer headers. */
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struct uio;
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caddr_t kern_vfs_bio_buffer_alloc(caddr_t v, int physmem_est);
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void bufinit(void);
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void bwillwrite(void);
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int buf_dirty_count_severe(void);
|
|
void bremfree(struct buf *);
|
|
int bread(struct vnode *, daddr_t, int, struct ucred *, struct buf **);
|
|
int breadn(struct vnode *, daddr_t, int, daddr_t *, int *, int,
|
|
struct ucred *, struct buf **);
|
|
int bwrite(struct buf *);
|
|
void bdwrite(struct buf *);
|
|
void bawrite(struct buf *);
|
|
void bdirty(struct buf *);
|
|
void bundirty(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 bufwait(struct buf *);
|
|
void bufdone(struct buf *);
|
|
void bufdonebio(struct bio *);
|
|
|
|
void cluster_callback(struct buf *);
|
|
int cluster_read(struct vnode *, u_quad_t, daddr_t, long,
|
|
struct ucred *, long, int, struct buf **);
|
|
int cluster_wbuild(struct vnode *, long, daddr_t, int);
|
|
void cluster_write(struct buf *, u_quad_t, int);
|
|
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 *);
|
|
void 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 *);
|
|
struct buf *trypbuf(int *);
|
|
|
|
#endif /* _KERNEL */
|
|
|
|
#endif /* !_SYS_BUF_H_ */
|