/*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2016 Apple Computer, Inc. All rights reserved.
*
- * @APPLE_LICENSE_HEADER_START@
- *
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License"). You may not use this file except in compliance with the
- * License. Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
- *
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ *
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
- * License for the specific language governing rights and limitations
- * under the License.
- *
- * @APPLE_LICENSE_HEADER_END@
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
/*
*/
#ifndef _SYS_BUF_H_
-#define _SYS_BUF_H_
-#include <sys/queue.h>
-#include <sys/errno.h>
+#define _SYS_BUF_H_
-#include <sys/vm.h>
+#include <sys/cdefs.h>
+#include <sys/kernel_types.h>
+#include <sys/ucred.h>
+#include <mach/memory_object_types.h>
-#define NOLIST ((struct buf *)0x87654321)
-#include <sys/cdefs.h>
+#define B_WRITE 0x00000000 /* Write buffer (pseudo flag). */
+#define B_READ 0x00000001 /* Read buffer. */
+#define B_ASYNC 0x00000002 /* Start I/O, do not wait. */
+#define B_NOCACHE 0x00000004 /* Do not cache block after use. */
+#define B_DELWRI 0x00000008 /* Delay I/O until buffer reused. */
+#define B_LOCKED 0x00000010 /* Locked in core (not reusable). */
+#define B_PHYS 0x00000020 /* I/O to user memory. */
+#define B_CLUSTER 0x00000040 /* UPL based I/O generated by cluster layer */
+#define B_PAGEIO 0x00000080 /* Page in/out */
+#define B_META 0x00000100 /* buffer contains meta-data. */
+#define B_RAW 0x00000200 /* Set by physio for raw transfers. */
+#define B_FUA 0x00000400 /* Write-through disk cache(if supported) */
+#define B_PASSIVE 0x00000800 /* PASSIVE I/Os are ignored by THROTTLE I/O */
+#define B_IOSTREAMING 0x00001000 /* sequential access pattern detected */
+#define B_THROTTLED_IO 0x00002000 /* low priority I/O (deprecated) */
+#define B_ENCRYPTED_IO 0x00004000 /* Encrypted I/O */
+#define B_STATICCONTENT 0x00008000 /* Buffer is likely to remain unaltered */
/*
- * The buffer header describes an I/O operation in the kernel.
- */
-struct buf {
- LIST_ENTRY(buf) b_hash; /* Hash chain. */
- LIST_ENTRY(buf) b_vnbufs; /* Buffer's associated vnode. */
- TAILQ_ENTRY(buf) b_freelist; /* Free list position if not active. */
- struct proc *b_proc; /* Associated proc; NULL if kernel. */
- volatile long b_flags; /* B_* flags. */
- int b_error; /* Errno value. */
- long b_bufsize; /* Allocated buffer size. */
- long b_bcount; /* Valid bytes in buffer. */
- long b_resid; /* Remaining I/O. */
- dev_t b_dev; /* Device associated with buffer. */
- struct {
- caddr_t b_addr; /* Memory, superblocks, indirect etc.*/
- } b_un;
- void *b_saveaddr; /* Original b_addr for physio. */
- daddr_t b_lblkno; /* Logical block number. */
- daddr_t b_blkno; /* Underlying physical block number. */
- /* Function to call upon completion. */
- void (*b_iodone) __P((struct buf *));
- struct vnode *b_vp; /* Device vnode. */
- int b_dirtyoff; /* Offset in buffer of dirty region. */
- int b_dirtyend; /* Offset of end of dirty region. */
- int b_validoff; /* Offset in buffer of valid region. */
- int b_validend; /* Offset of end of valid region. */
- struct ucred *b_rcred; /* Read credentials reference. */
- struct ucred *b_wcred; /* Write credentials reference. */
- int b_timestamp; /* timestamp for queuing operation */
- long b_vectorcount; /* number of vectors in b_vectorlist */
- void *b_vectorlist; /* vector list for I/O */
- void *b_pagelist; /* to save pagelist info */
- long b_vects[2]; /* vectorlist when b_vectorcount is 1 */
- long b_whichq; /* the free list the buffer belongs to */
- TAILQ_ENTRY(buf) b_act; /* Device driver queue when active */
- void *b_drvdata; /* Device driver private use */
-};
+ * make sure to check when adding flags that
+ * that the new flags don't overlap the definitions
+ * in buf_internal.h
+ */
+
+__BEGIN_DECLS
+
+/*!
+ * @function buf_markaged
+ * @abstract Mark a buffer as "aged," i.e. as a good candidate to be discarded and reused after buf_brelse().
+ * @param bp Buffer to mark.
+ */
+void buf_markaged(buf_t bp);
+
+/*!
+ * @function buf_markinvalid
+ * @abstract Mark a buffer as not having valid data and being ready for immediate reuse after buf_brelse().
+ * @param bp Buffer to mark.
+ */
+void buf_markinvalid(buf_t bp);
+
+/*!
+ * @function buf_markdelayed
+ * @abstract Mark a buffer as a delayed write: mark it dirty without actually scheduling I/O.
+ * @discussion Data will be flushed to disk at some later time, not with brelse(). A sync()/fsync()
+ * or pressure necessitating reuse of the buffer will cause it to be written back to disk.
+ * @param bp Buffer to mark.
+ */
+void buf_markdelayed(buf_t bp);
+
+void buf_markclean(buf_t);
+
+/*!
+ * @function buf_markeintr
+ * @abstract Mark a buffer as having been interrupted during I/O.
+ * @discussion Waiters for I/O to complete (buf_biowait()) will return with EINTR when woken up.
+ * buf_markeintr does not itself do a wakeup.
+ * @param bp Buffer to mark.
+ */
+void buf_markeintr(buf_t bp);
+
+/*!
+ * @function buf_markfua
+ * @abstract Mark a buffer for write through disk cache, if disk supports it.
+ * @param bp Buffer to mark.
+ */
+void buf_markfua(buf_t bp);
+
+/*!
+ * @function buf_fua
+ * @abstract Check if a buffer is marked for write through disk caches.
+ * @param bp Buffer to test.
+ * @return Nonzero if buffer is marked for write-through, 0 if not.
+ */
+int buf_fua(buf_t bp);
+
+/*!
+ * @function buf_valid
+ * @abstract Check if a buffer contains valid data.
+ * @param bp Buffer to test.
+ * @return Nonzero if buffer has valid data, 0 if not.
+ */
+int buf_valid(buf_t bp);
+
+/*!
+ * @function buf_fromcache
+ * @abstract Check if a buffer's data was found in core.
+ * @discussion Will return truth after a buf_getblk that finds a valid buffer in the cache or the relevant
+ * data in core (but not in a buffer).
+ * @param bp Buffer to test.
+ * @return Nonzero if we got this buffer's data without doing I/O, 0 if not.
+ */
+int buf_fromcache(buf_t bp);
+
+/*!
+ * @function buf_upl
+ * @abstract Get the upl (Universal Page List) associated with a buffer.
+ * @discussion Buffers allocated with buf_alloc() are not returned with a upl, and
+ * traditional buffers only have a upl while an I/O is in progress.
+ * @param bp Buffer whose upl to grab.
+ * @return Buffer's upl if it has one, else NULL.
+ */
+void * buf_upl(buf_t bp);
+
+/*!
+ * @function buf_uploffset
+ * @abstract Get the offset into a UPL at which this buffer begins.
+ * @discussion This function should only be called on iobufs, i.e. buffers allocated with buf_alloc().
+ * @param bp Buffer whose uploffset to grab.
+ * @return Buffer's uploffset--does not check whether that value makes sense for this buffer.
+ */
+uint32_t buf_uploffset(buf_t bp);
+
+/*!
+ * @function buf_rcred
+ * @abstract Get the credential associated with a buffer for reading.
+ * @discussion No reference is taken; if the credential is to be held on to persistently, an additional
+ * reference must be taken with kauth_cred_ref.
+ * @param bp Buffer whose credential to grab.
+ * @return Credential if it exists, else NULL.
+ */
+kauth_cred_t buf_rcred(buf_t bp);
+
+/*!
+ * @function buf_wcred
+ * @abstract Get the credential associated with a buffer for writing.
+ * @discussion No reference is taken; if the credential is to be held on to persistently, an additional
+ * reference must be taken with kauth_cred_ref.
+ * @param bp Buffer whose credential to grab.
+ * @return Credential if it exists, else NULL.
+ */
+kauth_cred_t buf_wcred(buf_t bp);
+
+/*!
+ * @function buf_proc
+ * @abstract Get the process associated with this buffer.
+ * @discussion buf_proc() will generally return NULL; a process is currently only associated with
+ * a buffer in the event of a physio() call.
+ * @param bp Buffer whose associated process to find.
+ * @return Associated process, possibly NULL.
+ */
+proc_t buf_proc(buf_t bp);
+
+/*!
+ * @function buf_dirtyoff
+ * @abstract Get the starting offset of the dirty region associated with a buffer.
+ * @discussion The dirty offset is zero unless someone explicitly calls buf_setdirtyoff() (which the kernel does not).
+ * @param bp Buffer whose dirty offset to get.
+ * @return Dirty offset (0 if not explicitly changed).
+ */
+uint32_t buf_dirtyoff(buf_t bp);
+
+/*!
+ * @function buf_dirtyend
+ * @abstract Get the ending offset of the dirty region associated with a buffer.
+ * @discussion If the buffer's data was found incore and dirty, the dirty end is the size of the block; otherwise, unless
+ * someone outside of xnu explicitly changes it by calling buf_setdirtyend(), it will be zero.
+ * @param bp Buffer whose dirty end to get.
+ * @return 0 if buffer is found clean; size of buffer if found dirty. Can be set to any value by callers of buf_setdirtyend().
+ */
+uint32_t buf_dirtyend(buf_t bp);
+
+/*!
+ * @function buf_setdirtyoff
+ * @abstract Set the starting offset of the dirty region associated with a buffer.
+ * @discussion This value is zero unless someone set it explicitly.
+ * @param bp Buffer whose dirty end to set.
+ */
+void buf_setdirtyoff(buf_t bp, uint32_t);
+
+/*!
+ * @function buf_setdirtyend
+ * @abstract Set the ending offset of the dirty region associated with a buffer.
+ * @discussion If the buffer's data was found incore and dirty, the dirty end is the size of the block; otherwise, unless
+ * someone outside of xnu explicitly changes it by calling buf_setdirtyend(), it will be zero.
+ * @param bp Buffer whose dirty end to set.
+ */
+void buf_setdirtyend(buf_t bp, uint32_t);
+
+/*!
+ * @function buf_error
+ * @abstract Get the error value associated with a buffer.
+ * @discussion Errors are set with buf_seterror().
+ * @param bp Buffer whose error value to retrieve.
+ * @return Error value, directly.
+ */
+errno_t buf_error(buf_t bp);
+
+/*!
+ * @function buf_seterror
+ * @abstract Set an error value on a buffer.
+ * @param bp Buffer whose error value to set.
+ */
+void buf_seterror(buf_t bp, errno_t);
+
+/*!
+ * @function buf_setflags
+ * @abstract Set flags on a buffer.
+ * @discussion buffer_flags |= flags
+ * @param bp Buffer whose flags to set.
+ * @param flags Flags to add to buffer's mask. B_LOCKED/B_NOCACHE/B_ASYNC/B_READ/B_WRITE/B_PAGEIO/B_FUA
+ */
+void buf_setflags(buf_t bp, int32_t flags);
+
+/*!
+ * @function buf_clearflags
+ * @abstract Clear flags on a buffer.
+ * @discussion buffer_flags &= ~flags
+ * @param bp Buffer whose flags to clear.
+ * @param flags Flags to remove from buffer's mask. B_LOCKED/B_NOCACHE/B_ASYNC/B_READ/B_WRITE/B_PAGEIO/B_FUA
+ */
+void buf_clearflags(buf_t bp, int32_t flags);
+
+/*!
+ * @function buf_flags
+ * @abstract Get flags set on a buffer.
+ * @discussion Valid flags are B_LOCKED/B_NOCACHE/B_ASYNC/B_READ/B_WRITE/B_PAGEIO/B_FUA.
+ * @param bp Buffer whose flags to grab.
+ * @return flags.
+ */
+int32_t buf_flags(buf_t bp);
+
+/*!
+ * @function buf_reset
+ * @abstract Reset I/O flag state on a buffer.
+ * @discussion Clears current flags on a buffer (internal and external) and allows some new flags to be set.
+ * Used perhaps to prepare an iobuf for reuse.
+ * @param bp Buffer whose flags to grab.
+ * @param flags Flags to set on buffer: B_READ, B_WRITE, B_ASYNC, B_NOCACHE.
+ */
+void buf_reset(buf_t bp, int32_t flags);
+
+/*!
+ * @function buf_map
+ * @abstract Get virtual mappings for buffer data.
+ * @discussion For buffers created through buf_getblk() (i.e. traditional buffer cache usage),
+ * buf_map() just returns the address at which data was mapped by but_getblk(). For a B_CLUSTER buffer, i.e. an iobuf
+ * whose upl state is managed manually, there are two possibilities. If the buffer was created
+ * with an underlying "real" buffer through cluster_bp(), the mapping of the "real" buffer is returned.
+ * Otherwise, the buffer was created with buf_alloc() and buf_setupl() was subsequently called; buf_map()
+ * will call ubc_upl_map() to get a mapping for the buffer's upl and return the start of that mapping
+ * plus the buffer's upl offset (set in buf_setupl()). In the last case, buf_unmap() must later be called
+ * to tear down the mapping. NOTE: buf_map() does not set the buffer data pointer; this must be done with buf_setdataptr().
+ * @param bp Buffer whose mapping to find or create.
+ * @param io_addr Destination for mapping address.
+ * @return 0 for success, ENOMEM if unable to map the buffer.
+ */
+errno_t buf_map(buf_t bp, caddr_t *io_addr);
+
+/*!
+ * @function buf_unmap
+ * @abstract Release mappings for buffer data.
+ * @discussion For buffers created through buf_getblk() (i.e. traditional buffer cache usage),
+ * buf_unmap() does nothing; buf_brelse() will take care of unmapping. For a B_CLUSTER buffer, i.e. an iobuf
+ * whose upl state is managed manually, there are two possibilities. If the buffer was created
+ * with an underlying "real" buffer through cluster_bp(), buf_unmap() does nothing; buf_brelse() on the
+ * underlying buffer will tear down the mapping. Otherwise, the buffer was created with buf_alloc() and
+ * buf_setupl() was subsequently called; buf_map() created the mapping. In this case, buf_unmap() will
+ * unmap the buffer.
+ * @param bp Buffer whose mapping to find or create.
+ * @return 0 for success, EINVAL if unable to unmap buffer.
+ */
+errno_t buf_unmap(buf_t bp);
+
+/*!
+ * @function buf_setdrvdata
+ * @abstract Set driver-specific data on a buffer.
+ * @param bp Buffer whose driver-data to set.
+ * @param drvdata Opaque driver data.
+ */
+void buf_setdrvdata(buf_t bp, void *drvdata);
+
+/*!
+ * @function buf_setdrvdata
+ * @abstract Get driver-specific data from a buffer.
+ * @param bp Buffer whose driver data to get.
+ * @return Opaque driver data.
+ */
+void * buf_drvdata(buf_t bp);
+
+/*!
+ * @function buf_setfsprivate
+ * @abstract Set filesystem-specific data on a buffer.
+ * @param bp Buffer whose filesystem data to set.
+ * @param fsprivate Opaque filesystem data.
+ */
+void buf_setfsprivate(buf_t bp, void *fsprivate);
+
+/*!
+ * @function buf_fsprivate
+ * @abstract Get filesystem-specific data from a buffer.
+ * @param bp Buffer whose filesystem data to get.
+ * @return Opaque filesystem data.
+ */
+void * buf_fsprivate(buf_t bp);
+
+/*!
+ * @function buf_blkno
+ * @abstract Get physical block number associated with a buffer, in the sense of VNOP_BLOCKMAP.
+ * @discussion When a buffer's physical block number is the same is its logical block number, then the physical
+ * block number is considered uninitialized. A physical block number of -1 indicates that there is no valid
+ * physical mapping (e.g. the logical block is invalid or corresponds to a sparse region in a file). Physical
+ * block number is normally set by the cluster layer or by buf_getblk().
+ * @param bp Buffer whose physical block number to get.
+ * @return Block number.
+ */
+daddr64_t buf_blkno(buf_t bp);
+
+/*!
+ * @function buf_lblkno
+ * @abstract Get logical block number associated with a buffer.
+ * @discussion Logical block number is set on traditionally-used buffers by an argument passed to buf_getblk(),
+ * for example by buf_bread().
+ * @param bp Buffer whose logical block number to get.
+ * @return Block number.
+ */
+daddr64_t buf_lblkno(buf_t bp);
+
+/*!
+ * @function buf_setblkno
+ * @abstract Set physical block number associated with a buffer.
+ * @discussion Physical block number is generally set by the cluster layer or by buf_getblk().
+ * @param bp Buffer whose physical block number to set.
+ * @param blkno Block number to set.
+ */
+void buf_setblkno(buf_t bp, daddr64_t blkno);
+
+/*!
+ * @function buf_setlblkno
+ * @abstract Set logical block number associated with a buffer.
+ * @discussion Logical block number is set on traditionally-used buffers by an argument passed to buf_getblk(),
+ * for example by buf_bread().
+ * @param bp Buffer whose logical block number to set.
+ * @param lblkno Block number to set.
+ */
+void buf_setlblkno(buf_t bp, daddr64_t lblkno);
+
+/*!
+ * @function buf_count
+ * @abstract Get count of valid bytes in a buffer. This may be less than the space allocated to the buffer.
+ * @param bp Buffer whose byte count to get.
+ * @return Byte count.
+ */
+uint32_t buf_count(buf_t bp);
+
+/*!
+ * @function buf_size
+ * @abstract Get size of data region allocated to a buffer.
+ * @discussion May be larger than amount of valid data in buffer.
+ * @param bp Buffer whose size to get.
+ * @return Size.
+ */
+uint32_t buf_size(buf_t bp);
+
+/*!
+ * @function buf_resid
+ * @abstract Get a count of bytes which were not consumed by an I/O on a buffer.
+ * @discussion Set when an I/O operations completes.
+ * @param bp Buffer whose outstanding count to get.
+ * @return Count of unwritten/unread bytes.
+ */
+uint32_t buf_resid(buf_t bp);
+
+/*!
+ * @function buf_setcount
+ * @abstract Set count of valid bytes in a buffer. This may be less than the space allocated to the buffer.
+ * @param bp Buffer whose byte count to set.
+ * @param bcount Count to set.
+ */
+void buf_setcount(buf_t bp, uint32_t bcount);
+
+/*!
+ * @function buf_setsize
+ * @abstract Set size of data region allocated to a buffer.
+ * @discussion May be larger than amount of valid data in buffer. Should be used by
+ * code which is manually providing storage for an iobuf, one allocated with buf_alloc().
+ * @param bp Buffer whose size to set.
+ */
+void buf_setsize(buf_t bp, uint32_t);
+
+/*!
+ * @function buf_setresid
+ * @abstract Set a count of bytes outstanding for I/O in a buffer.
+ * @discussion Set when an I/O operations completes. Examples: called by IOStorageFamily when I/O
+ * completes, often called on an "original" buffer when using a manipulated buffer to perform I/O
+ * on behalf of the first.
+ * @param bp Buffer whose outstanding count to set.
+ */
+void buf_setresid(buf_t bp, uint32_t resid);
+
+/*!
+ * @function buf_setdataptr
+ * @abstract Set the address at which a buffer's data will be stored.
+ * @discussion In traditional buffer use, the data pointer will be set automatically. This routine is
+ * useful with iobufs (allocated with buf_alloc()).
+ * @param bp Buffer whose data pointer to set.
+ * @param data Pointer to data region.
+ */
+void buf_setdataptr(buf_t bp, uintptr_t data);
+
+/*!
+ * @function buf_dataptr
+ * @abstract Get the address at which a buffer's data is stored; for iobufs, this must
+ * be set with buf_setdataptr(). See buf_map().
+ * @param bp Buffer whose data pointer to retrieve.
+ * @return Data pointer; NULL if unset.
+ */
+uintptr_t buf_dataptr(buf_t bp);
+
+/*!
+ * @function buf_vnode
+ * @abstract Get the vnode associated with a buffer.
+ * @discussion Every buffer is associated with a file. Because there is an I/O in flight,
+ * there is an iocount on this vnode; it is returned WITHOUT an extra iocount, and vnode_put()
+ * need NOT be called.
+ * @param bp Buffer whose vnode to retrieve.
+ * @return Buffer's vnode.
+ */
+vnode_t buf_vnode(buf_t bp);
+
+/*!
+ * @function buf_setvnode
+ * @abstract Set the vnode associated with a buffer.
+ * @discussion This call need not be used on traditional buffers; it is for use with iobufs.
+ * @param bp Buffer whose vnode to set.
+ * @param vp The vnode to attach to the buffer.
+ */
+void buf_setvnode(buf_t bp, vnode_t vp);
+
+/*!
+ * @function buf_device
+ * @abstract Get the device ID associated with a buffer.
+ * @discussion In traditional buffer use, this value is NODEV until buf_strategy() is called unless
+ * buf_getblk() was passed a device vnode. It is set on an iobuf if buf_alloc() is passed a device
+ * vnode or if buf_setdevice() is called.
+ * @param bp Buffer whose device ID to retrieve.
+ * @return Device id.
+ */
+dev_t buf_device(buf_t bp);
+
+/*!
+ * @function buf_setdevice
+ * @abstract Set the device associated with a buffer.
+ * @discussion A buffer's device is set in buf_strategy() (or in buf_getblk() if the file is a device).
+ * It is also set on an iobuf if buf_alloc() is passed a device vnode.
+ * @param bp Buffer whose device ID to set.
+ * @param vp Device to set on the buffer.
+ * @return 0 for success, EINVAL if vp is not a device file.
+ */
+errno_t buf_setdevice(buf_t bp, vnode_t vp);
+
+/*!
+ * @function buf_strategy
+ * @abstract Pass an I/O request for a buffer down to the device layer.
+ * @discussion This is one of the most important routines in the buffer cache layer. For buffers obtained
+ * through buf_getblk, it handles finding physical block numbers for the I/O (with VNOP_BLKTOOFF and
+ * VNOP_BLOCKMAP), packaging the I/O into page-sized chunks, and initiating I/O on the disk by calling
+ * the device's strategy routine. If a buffer's UPL has been set manually with buf_setupl(), it assumes
+ * that the request is already correctly configured with a block number and a size divisible by page size
+ * and will just call directly to the device.
+ * @param devvp Device on which to perform I/O
+ * @param ap vnop_strategy_args structure (most importantly, a buffer).
+ * @return 0 for success, or errors from filesystem or device layers.
+ */
+errno_t buf_strategy(vnode_t devvp, void *ap);
/*
- * For portability with historic industry practice, the cylinder number has
- * to be maintained in the `b_resid' field.
+ * Flags for buf_invalblkno()
*/
-#define b_cylinder b_resid /* Cylinder number for disksort(). */
+#define BUF_WAIT 0x01
-/* Device driver compatibility definitions. */
-#define b_active b_bcount /* Driver queue head: drive active. */
-#define b_data b_un.b_addr /* b_un.b_addr is not changeable. */
-#define b_errcnt b_resid /* Retry count while I/O in progress. */
-#define iodone biodone /* Old name for biodone. */
-#define iowait biowait /* Old name for biowait. */
+/*!
+ * @function buf_invalblkno
+ * @abstract Invalidate a filesystem logical block in a file.
+ * @discussion buf_invalblkno() tries to make the data for a given block in a file
+ * invalid; if the buffer for that block is found in core and is not busy, we mark it
+ * invalid and call buf_brelse() (see "flags" param for what happens if the buffer is busy).
+ * buf_brelse(), noticing that it is invalid, will
+ * will return the buffer to the empty-buffer list and tell the VM subsystem to abandon
+ * the relevant pages. Data will not be written to backing store--it will be cast aside.
+ * Note that this function will only work if the block in question has been
+ * obtained with a buf_getblk(). If data has been read into core without using
+ * traditional buffer cache routines, buf_invalblkno() will not be able to invalidate it--this
+ * includes the use of iobufs.
+ * @param vp vnode whose block to invalidate.
+ * @param lblkno Logical block number.
+ * @param flags BUF_WAIT: wait for busy buffers to become unbusy and invalidate them then. Otherwise,
+ * just return EBUSY for busy blocks.
+ * @return 0 for success, EINVAL if vp is not a device file.
+ */
+errno_t buf_invalblkno(vnode_t vp, daddr64_t lblkno, int flags);
-/* cluster_io definitions for use with io bufs */
-#define b_uploffset b_bufsize
-#define b_trans_head b_freelist.tqe_prev
-#define b_trans_next b_freelist.tqe_next
-#define b_real_bp b_saveaddr
+/*!
+ * @function buf_callback
+ * @abstract Get the function set to be called when I/O on a buffer completes.
+ * @discussion A function returned by buf_callback was originally set with buf_setcallback().
+ * @param bp Buffer whose callback to get.
+ * @return 0 for success, or errors from filesystem or device layers.
+ */
+void * buf_callback(buf_t bp);
+
+/*!
+ * @function buf_setcallback
+ * @abstract Set a function to be called once when I/O on a buffer completes.
+ * @discussion A one-shot callout set with buf_setcallback() will be called from buf_biodone()
+ * when I/O completes. It will be passed the "transaction" argument as well as the buffer.
+ * buf_setcallback() also marks the buffer as B_ASYNC.
+ * @param bp Buffer whose callback to set.
+ * @param callback function to use as callback.
+ * @param transaction Additional argument to callback function.
+ * @return 0; always succeeds.
+ */
+errno_t buf_setcallback(buf_t bp, void (*callback)(buf_t, void *), void *transaction);
+
+/*!
+ * @function buf_setupl
+ * @abstract Set the UPL (Universal Page List), and offset therein, on a buffer.
+ * @discussion buf_setupl() should only be called on buffers allocated with buf_alloc().
+ * A subsequent call to buf_map() will map the UPL and give back the address at which data
+ * begins. After buf_setupl() is called, a buffer is marked B_CLUSTER; when this is the case,
+ * buf_strategy() assumes that a buffer is correctly configured to be passed to the device
+ * layer without modification. Passing a NULL upl will clear the upl and the B_CLUSTER flag on the
+ * buffer.
+ * @param bp Buffer whose upl to set.
+ * @param upl UPL to set in the buffer.
+ * @param offset Offset within upl at which relevant data begin.
+ * @return 0 for success, EINVAL if the buffer was not allocated with buf_alloc().
+ */
+errno_t buf_setupl(buf_t bp, upl_t upl, uint32_t offset);
+
+/*!
+ * @function buf_clone
+ * @abstract Clone a buffer with a restricted range and an optional callback.
+ * @discussion Generates a buffer which is identical to its "bp" argument except that
+ * it spans a subset of the data of the original. The buffer to be cloned should
+ * have been allocated with buf_alloc(). Checks its arguments to make sure
+ * that the data subset is coherent. Optionally, adds a callback function and argument to it
+ * to be called when I/O completes (as with buf_setcallback(), but B_ASYNC is not set). If the original buffer had
+ * a upl set through buf_setupl(), this upl is copied to the new buffer; otherwise, the original's
+ * data pointer is used raw. The buffer must be released with buf_free().
+ * @param bp Buffer to clone.
+ * @param io_offset Offset, relative to start of data in original buffer, at which new buffer's data will begin.
+ * @param io_size Size of buffer region in new buffer, in the sense of buf_count().
+ * @param iodone Callback to be called from buf_biodone() when I/O completes, in the sense of buf_setcallback().
+ * @param arg Argument to pass to iodone() callback.
+ * @return NULL if io_offset/io_size combination is invalid for the buffer to be cloned; otherwise, the new buffer.
+ */
+buf_t buf_clone(buf_t bp, int io_offset, int io_size, void (*iodone)(buf_t, void *), void *arg);
+
+
+/*!
+ * @function buf_create_shadow
+ * @abstract Create a shadow buffer with optional private storage and an optional callback.
+ * @param bp Buffer to shadow.
+ * @param force_copy If TRUE, do not link the shadaow to 'bp' and if 'external_storage' == NULL,
+ * force a copy of the data associated with 'bp'.
+ * @param external_storage If non-NULL, associate it with the new buffer as its storage instead of the
+ * storage currently associated with 'bp'.
+ * @param iodone Callback to be called from buf_biodone() when I/O completes, in the sense of buf_setcallback().
+ * @param arg Argument to pass to iodone() callback.
+ * @return NULL if the buffer to be shadowed is not B_META or a primary buffer (i.e. not a shadow buffer); otherwise, the new buffer.
+ */
+
+buf_t buf_create_shadow(buf_t bp, boolean_t force_copy, uintptr_t external_storage, void (*iodone)(buf_t, void *), void *arg);
+
+
+/*!
+ * @function buf_shadow
+ * @abstract returns true if 'bp' is a shadow of another buffer.
+ * @param bp Buffer to query.
+ * @return 1 if 'bp' is a shadow, 0 otherwise.
+ */
+int buf_shadow(buf_t bp);
+
+
+/*!
+ * @function buf_alloc
+ * @abstract Allocate an uninitialized buffer.
+ * @discussion A buffer returned by buf_alloc() is marked as busy and as an iobuf; it has no storage set up and must be
+ * set up using buf_setdataptr() or buf_setupl()/buf_map().
+ * @param vp vnode to associate with the buffer: optionally NULL. If vp is a device file, then
+ * the buffer's associated device will be set. If vp is NULL, it can be set later with buf_setvnode().
+ * @return New buffer.
+ */
+buf_t buf_alloc(vnode_t vp);
+
+/*!
+ * @function buf_free
+ * @abstract Free a buffer that was allocated with buf_alloc().
+ * @discussion The storage (UPL, data pointer) associated with an iobuf must be freed manually.
+ * @param bp The buffer to free.
+ */
+void buf_free(buf_t bp);
/*
- * These flags are kept in b_flags.
- */
-#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_BAD 0x00000008 /* Bad block revectoring in progress. */
-#define B_BUSY 0x00000010 /* I/O in progress. */
-#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_DIRTY 0x00000100 /* Dirty page to be pushed out async. */
-#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_WASDIRTY 0x00001000 /* page was found dirty in the VM cache */
-#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_PAGEOUT 0x00010000 /* Page out indicator... */
-#define B_PGIN 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_TAPE 0x00200000 /* Magnetic tape I/O. */
-#define B_PAGELIST 0x00400000 /* Buffer describes pagelist I/O. */
-#define B_WANTED 0x00800000 /* Process wants this buffer. */
-#define B_WRITE 0x00000000 /* Write buffer (pseudo flag). */
-#define B_WRITEINPROG 0x01000000 /* Write in progress. */
-#define B_UNUSED0 0x02000000 /* Unused bit */
-#define B_UNUSED1 0x04000000 /* Unused bit */
-#define B_NEED_IODONE 0x08000000
- /* need to do a biodone on the */
- /* real_bp associated with a cluster_io */
-#define B_COMMIT_UPL 0x10000000
- /* commit pages in upl when */
- /* I/O completes/fails */
-#define B_ZALLOC 0x20000000 /* b_data is zalloc()ed */
-#define B_META 0x40000000 /* buffer contains meta-data. */
-#define B_VECTORLIST 0x80000000 /* Used by device drivers. */
+ * flags for buf_invalidateblks
+ */
+#define BUF_WRITE_DATA 0x0001 /* write data blocks first */
+#define BUF_SKIP_META 0x0002 /* skip over metadata blocks */
+#define BUF_INVALIDATE_LOCKED 0x0004 /* force B_LOCKED blocks to be invalidated */
+/*!
+ * @function buf_invalidateblks
+ * @abstract Invalidate all the blocks associated with a vnode.
+ * @discussion This function does for all blocks associated with a vnode what buf_invalblkno does for one block.
+ * Again, it will only be able to invalidate data which were populated with traditional buffer cache routines,
+ * i.e. by buf_getblk() and callers thereof. Unlike buf_invalblkno(), it can be made to write dirty data to disk
+ * rather than casting it aside.
+ * @param vp The vnode whose data to invalidate.
+ * @param flags BUF_WRITE_DATA: write dirty data to disk with VNOP_BWRITE() before kicking buffer cache entries out.
+ * BUF_SKIP_META: do not invalidate metadata blocks.
+ * @param slpflag Flags to pass to "msleep" while waiting to acquire busy buffers.
+ * @param slptimeo Timeout in "hz" (1/100 second) to wait for a buffer to become unbusy before waking from sleep
+ * and re-starting the scan.
+ * @return 0 for success, error values from msleep().
+ */
+int buf_invalidateblks(vnode_t vp, int flags, int slpflag, int slptimeo);
/*
- * 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 allocation routines. */
-#define B_CLRBUF 0x01 /* Request allocated buffer be cleared. */
-#define B_SYNC 0x02 /* Do all allocations synchronously. */
-#define B_NOBUFF 0x04 /* Do not allocate struct buf */
-
-/* Flags for operation type in getblk() */
-#define BLK_READ 0x01 /* buffer for read */
-#define BLK_WRITE 0x02 /* buffer for write */
-#define BLK_PAGEIN 0x04 /* buffer for pagein */
-#define BLK_PAGEOUT 0x08 /* buffer for pageout */
-#define BLK_META 0x10 /* buffer for metadata */
-#define BLK_CLREAD 0x20 /* buffer for cluster read */
-#define BLK_CLWRITE 0x40 /* buffer for cluster write */
-
-#ifdef KERNEL
-extern int nbuf; /* The number of buffer headers */
-extern struct buf *buf; /* The buffer headers. */
+ * flags for buf_flushdirtyblks and buf_iterate
+ */
+#define BUF_SKIP_NONLOCKED 0x01
+#define BUF_SKIP_LOCKED 0x02
+#define BUF_SCAN_CLEAN 0x04 /* scan the clean buffers */
+#define BUF_SCAN_DIRTY 0x08 /* scan the dirty buffers */
+#define BUF_NOTIFY_BUSY 0x10 /* notify the caller about the busy pages during the scan */
+
+
+#define BUF_RETURNED 0
+#define BUF_RETURNED_DONE 1
+#define BUF_CLAIMED 2
+#define BUF_CLAIMED_DONE 3
+/*!
+ * @function buf_flushdirtyblks
+ * @abstract Write dirty file blocks to disk.
+ * @param vp The vnode whose blocks to flush.
+ * @param wait Wait for writes to complete before returning.
+ * @param flags Can pass zero, meaning "flush all dirty buffers."
+ * BUF_SKIP_NONLOCKED: Skip buffers which are not busy when we encounter them.
+ * BUF_SKIP_LOCKED: Skip buffers which are busy when we encounter them.
+ * @param msg String to pass to msleep().
+ */
+void buf_flushdirtyblks(vnode_t vp, int wait, int flags, const char *msg);
+
+/*!
+ * @function buf_iterate
+ * @abstract Perform some operation on all buffers associated with a vnode.
+ * @param vp The vnode whose buffers to scan.
+ * @param callout Function to call on each buffer. Should return one of:
+ * BUF_RETURNED: buf_iterate() should call buf_brelse() on the buffer.
+ * BUF_RETURNED_DONE: buf_iterate() should call buf_brelse() on the buffer and then stop iterating.
+ * BUF_CLAIMED: buf_iterate() should continue iterating (and not call buf_brelse()).
+ * BUF_CLAIMED_DONE: buf_iterate() should stop iterating (and not call buf_brelse()).
+ * @param flags
+ * BUF_SKIP_NONLOCKED: Skip buffers which are not busy when we encounter them. BUF_SKIP_LOCKED: Skip buffers which are busy when we encounter them.
+ * BUF_SCAN_CLEAN: Call out on clean buffers.
+ * BUF_SCAN_DIRTY: Call out on dirty buffers.
+ * BUF_NOTIFY_BUSY: If a buffer cannot be acquired, pass a NULL buffer to callout; otherwise,
+ * that buffer will be silently skipped.
+ * @param arg Argument to pass to callout in addition to buffer.
+ */
+void buf_iterate(vnode_t vp, int (*callout)(buf_t, void *), int flags, void *arg);
+
+/*!
+ * @function buf_clear
+ * @abstract Zero out the storage associated with a buffer.
+ * @discussion Calls buf_map() to get the buffer's data address; for a B_CLUSTER
+ * buffer (one which has had buf_setupl() called on it), it tries to map the buffer's
+ * UPL into memory; should only be called once during the life cycle of an iobuf (one allocated
+ * with buf_alloc()).
+ * @param bp The buffer to zero out.
+ */
+void buf_clear(buf_t bp);
+
+/*!
+ * @function buf_bawrite
+ * @abstract Start an asychronous write on a buffer.
+ * @discussion Calls VNOP_BWRITE to start the process of propagating an asynchronous write down to the device layer.
+ * Callers can wait for writes to complete at their discretion using buf_biowait(). When this function is called,
+ * data should already have been written to the buffer's data region.
+ * @param bp The buffer on which to initiate I/O.
+ * @return EWOULDBLOCK if write count is high and "throttle" is zero; otherwise, errors from VNOP_BWRITE.
+ */
+errno_t buf_bawrite(buf_t bp);
+
+/*!
+ * @function buf_bdwrite
+ * @abstract Mark a buffer for delayed write.
+ * @discussion Marks a buffer as waiting for delayed write and the current I/O as complete; data will be written to backing store
+ * before the buffer is reused, but it will not be queued for I/O immediately. Note that for buffers allocated
+ * with buf_alloc(), there are no such guarantees; you must take care of your own flushing to disk. If
+ * the number of delayed writes pending on the system is greater than an internal limit and the caller has not
+ * requested otherwise [see return_error] , buf_bdwrite() will unilaterally launch an asynchronous I/O with buf_bawrite() to keep the pile of
+ * delayed writes from getting too large.
+ * @param bp The buffer to mark for delayed write.
+ * @return EAGAIN for return_error != 0 case, 0 for succeess, errors from buf_bawrite.
+ */
+errno_t buf_bdwrite(buf_t bp);
+
+/*!
+ * @function buf_bwrite
+ * @abstract Write a buffer's data to backing store.
+ * @discussion Once the data in a buffer has been modified, buf_bwrite() starts sending it to disk by calling
+ * VNOP_STRATEGY. Unless B_ASYNC has been set on the buffer (by buf_setflags() or otherwise), data will have
+ * been written to disk when buf_bwrite() returns. See Bach (p 56).
+ * @param bp The buffer to write to disk.
+ * @return 0 for success; errors from buf_biowait().
+ */
+errno_t buf_bwrite(buf_t bp);
+
+/*!
+ * @function buf_biodone
+ * @abstract Mark an I/O as completed.
+ * @discussion buf_biodone() should be called by whosoever decides that an I/O on a buffer is complete; for example,
+ * IOStorageFamily. It clears the dirty flag on a buffer and signals on the vnode that a write has completed
+ * with vnode_writedone(). If a callout or filter has been set on the buffer, that function is called. In the case
+ * of a callout, that function is expected to take care of cleaning up and freeing the buffer.
+ * Otherwise, if the buffer is marked B_ASYNC (e.g. it was passed to buf_bawrite()), then buf_biodone()
+ * considers itself justified in calling buf_brelse() to return it to free lists--no one is waiting for it. Finally,
+ * waiters on the bp (e.g. in buf_biowait()) are woken up.
+ * @param bp The buffer to mark as done with I/O.
+ */
+void buf_biodone(buf_t bp);
+
+/*!
+ * @function buf_biowait
+ * @abstract Wait for I/O on a buffer to complete.
+ * @discussion Waits for I/O on a buffer to finish, as marked by a buf_biodone() call.
+ * @param bp The buffer to wait on.
+ * @return 0 for a successful wait; nonzero the buffer has been marked as EINTR or had an error set on it.
+ */
+errno_t buf_biowait(buf_t bp);
+
+/*!
+ * @function buf_brelse
+ * @abstract Release any claim to a buffer, sending it back to free lists.
+ * @discussion buf_brelse() cleans up buffer state and releases a buffer to the free lists. If the buffer
+ * is not marked invalid and its pages are dirty (e.g. a delayed write was made), its data will be commited
+ * to backing store. If it is marked invalid, its data will be discarded completely.
+ * A valid, cacheable buffer will be put on a list and kept in the buffer hash so it
+ * can be found again; otherwise, it will be dissociated from its vnode and treated as empty. Which list a valid
+ * buffer is placed on depends on the use of buf_markaged(), whether it is metadata, and the B_LOCKED flag. A
+ * B_LOCKED buffer will not be available for reuse by other files, though its data may be paged out.
+ * Note that buf_brelse() is intended for use with traditionally allocated buffers.
+ * @param bp The buffer to release.
+ */
+void buf_brelse(buf_t bp);
+
+/*!
+ * @function buf_bread
+ * @abstract Synchronously read a block of a file.
+ * @discussion buf_bread() is the traditional way to read a single logical block of a file through the buffer cache.
+ * It tries to find the buffer and corresponding page(s) in core, calls VNOP_STRATEGY if necessary to bring the data
+ * into memory, and waits for I/O to complete. It should not be used to read blocks of greater than 4K (one VM page)
+ * in size; use cluster routines for large reads. Indeed, the cluster layer is a more efficient choice for reading DATA
+ * unless you need some finely-tuned semantics that it cannot provide.
+ * @param vp The file from which to read.
+ * @param blkno The logical (filesystem) block number to read.
+ * @param size Size of block; do not use for sizes > 4K.
+ * @param cred Credential to store and use for reading from disk if data are not already in core.
+ * @param bpp Destination pointer for buffer.
+ * @return 0 for success, or an error from buf_biowait().
+ */
+errno_t buf_bread(vnode_t vp, daddr64_t blkno, int size, kauth_cred_t cred, buf_t *bpp);
+
+/*!
+ * @function buf_breadn
+ * @abstract Read a block from a file with read-ahead.
+ * @discussion buf_breadn() reads one block synchronously in the style of buf_bread() and fires
+ * off a specified set of asynchronous reads to improve the likelihood of future cache hits.
+ * It should not be used to read blocks of greater than 4K (one VM page) in size; use cluster
+ * routines for large reads. Indeed, the cluster layer is a more efficient choice for reading DATA
+ * unless you need some finely-tuned semantics that it cannot provide.
+ * @param vp The file from which to read.
+ * @param blkno The logical (filesystem) block number to read synchronously.
+ * @param size Size of block; do not use for sizes > 4K.
+ * @param rablks Array of logical block numbers for asynchronous read-aheads.
+ * @param rasizes Array of block sizes for asynchronous read-aheads, each index corresponding to same index in "rablks."
+ * @param nrablks Number of entries in read-ahead arrays.
+ * @param cred Credential to store and use for reading from disk if data are not already in core.
+ * @param bpp Destination pointer for buffer.
+ * @return 0 for success, or an error from buf_biowait().
+ */
+errno_t buf_breadn(vnode_t vp, daddr64_t blkno, int size, daddr64_t *rablks, int *rasizes, int nrablks, kauth_cred_t cred, buf_t *bpp);
+
+/*!
+ * @function buf_meta_bread
+ * @abstract Synchronously read a metadata block of a file.
+ * @discussion buf_meta_bread() is the traditional way to read a single logical block of a file through the buffer cache.
+ * It tries to find the buffer and corresponding page(s) in core, calls VNOP_STRATEGY if necessary to bring the data
+ * into memory, and waits for I/O to complete. It should not be used to read blocks of greater than 4K (one VM page)
+ * in size; use cluster routines for large reads. Reading meta-data through the traditional buffer cache, unlike
+ * reading data, is efficient and encouraged, especially if the blocks being read are significantly smaller than page size.
+ * @param vp The file from which to read.
+ * @param blkno The logical (filesystem) block number to read.
+ * @param size Size of block; do not use for sizes > 4K.
+ * @param cred Credential to store and use for reading from disk if data are not already in core.
+ * @param bpp Destination pointer for buffer.
+ * @return 0 for success, or an error from buf_biowait().
+ */
+errno_t buf_meta_bread(vnode_t vp, daddr64_t blkno, int size, kauth_cred_t cred, buf_t *bpp);
+
+/*!
+ * @function buf_meta_breadn
+ * @abstract Read a metadata block from a file with read-ahead.
+ * @discussion buf_meta_breadn() reads one block synchronously in the style of buf_meta_bread() and fires
+ * off a specified set of asynchronous reads to improve the likelihood of future cache hits.
+ * It should not be used to read blocks of greater than 4K (one VM page) in size; use cluster
+ * routines for large reads.
+ * @param vp The file from which to read.
+ * @param blkno The logical (filesystem) block number to read synchronously.
+ * @param size Size of block; do not use for sizes > 4K.
+ * @param rablks Array of logical block numbers for asynchronous read-aheads.
+ * @param rasizes Array of block sizes for asynchronous read-aheads, each index corresponding to same index in "rablks."
+ * @param nrablks Number of entries in read-ahead arrays.
+ * @param cred Credential to store and use for reading from disk if data are not already in core.
+ * @param bpp Destination pointer for buffer.
+ * @return 0 for success, or an error from buf_biowait().
+ */
+errno_t buf_meta_breadn(vnode_t vp, daddr64_t blkno, int size, daddr64_t *rablks, int *rasizes, int nrablks, kauth_cred_t cred, buf_t *bpp);
+
+/*!
+ * @function minphys
+ * @abstract Adjust a buffer's count to be no more than maximum physical I/O transfer size for the host architecture.
+ * @discussion physio() takes as a parameter a function to bound transfer sizes for each VNOP_STRATEGY() call. minphys()
+ * is a default implementation. It calls buf_setcount() to make the buffer's count the min() of its current count
+ * and the max I/O size for the host architecture.
+ * @param bp The buffer whose byte count to modify.
+ * @return New byte count.
+ */
+u_int minphys(buf_t bp);
+
+/*!
+ * @function physio
+ * @abstract Perform I/O on a device to/from target memory described by a uio.
+ * @discussion physio() allows I/O directly from a device to user-space memory. It waits
+ * for all I/O to complete before returning.
+ * @param f_strategy Strategy routine to call to initiate I/O.
+ * @param bp Buffer to configure and pass to strategy routine; can be NULL.
+ * @param dev Device on which to perform I/O.
+ * @param flags B_READ or B_WRITE.
+ * @param f_minphys Function which calls buf_setcount() to set a byte count which is suitably
+ * small for the device in question. Returns byte count that has been set (or unchanged) on the buffer.
+ * @param uio UIO describing the I/O operation.
+ * @param blocksize Logical block size for this vnode.
+ * @return 0 for success; EFAULT for an invalid uio; errors from buf_biowait().
+ */
+int physio(void (*f_strategy)(buf_t), buf_t bp, dev_t dev, int flags, u_int (*f_minphys)(buf_t), struct uio *uio, int blocksize);
-/* Macros to clear/set/test flags. */
-#define SET(t, f) (t) |= (f)
-#define CLR(t, f) (t) &= ~(f)
-#define ISSET(t, f) ((t) & (f))
/*
- * Definitions for the buffer free lists.
+ * Flags for operation type in getblk()
*/
-#define BQUEUES 5 /* number of free buffer queues */
+#define BLK_READ 0x01 /* buffer for read */
+#define BLK_WRITE 0x02 /* buffer for write */
+#define BLK_META 0x10 /* buffer for metadata */
+/*
+ * modifier for above flags... if set, getblk will only return
+ * a bp that is already valid... i.e. found in the cache
+ */
+#define BLK_ONLYVALID 0x80000000
-#define BQ_LOCKED 0 /* super-blocks &c */
-#define BQ_LRU 1 /* lru, useful buffers */
-#define BQ_AGE 2 /* rubbish */
-#define BQ_EMPTY 3 /* buffer headers with no memory */
-#define BQ_META 4 /* buffer containing metadata */
+/*!
+ * @function buf_getblk
+ * @abstract Traditional buffer cache routine to get a buffer corresponding to a logical block in a file.
+ * @discussion buf_getblk() gets a buffer, not necessarily containing valid data, representing a block in a file.
+ * A metadata buffer will be returned with its own zone-allocated storage, managed by the traditional buffer-cache
+ * layer, whereas data buffers will be returned hooked into backing by the UBC (which in fact controls the caching of data).
+ * buf_getblk() first looks for the buffer header in cache; if the buffer is in-core but busy, buf_getblk() will wait for it to become
+ * unbusy, depending on the slpflag and slptimeo parameters. If the buffer is found unbusy and is a metadata buffer,
+ * it must already contain valid data and will be returned directly; data buffers will have a UPL configured to
+ * prepare for interaction with the underlying UBC. If the buffer is found in core, it will be marked as such
+ * and buf_fromcache() will return truth. A buffer is allocated and initialized (but not filled with data)
+ * if none is found in core. buf_bread(), buf_breadn(), buf_meta_bread(), and buf_meta_breadn() all
+ * return buffers obtained with buf_getblk().
+ * @param vp File for which to get block.
+ * @param blkno Logical block number.
+ * @param size Size of block.
+ * @param slpflag Flag to pass to msleep() while waiting for buffer to become unbusy.
+ * @param slptimeo Time, in milliseconds, to wait for buffer to become unbusy. 0 means to wait indefinitely.
+ * @param operation BLK_READ: want a read buffer. BLK_WRITE: want a write buffer. BLK_META: want a metadata buffer. BLK_ONLYVALID:
+ * only return buffers which are found in core (do not allocate anew), and do not change buffer size. The last remark means
+ * that if a given logical block is found in core with a different size than what is requested, the buffer size will not be modified.
+ * @return Buffer found in core or newly allocated, either containing valid data or ready for I/O.
+ */
+buf_t buf_getblk(vnode_t vp, daddr64_t blkno, int size, int slpflag, int slptimeo, int operation);
-__BEGIN_DECLS
-int allocbuf __P((struct buf *, int));
-void bawrite __P((struct buf *));
-void bdwrite __P((struct buf *));
-void biodone __P((struct buf *));
-int biowait __P((struct buf *));
-int bread __P((struct vnode *, daddr_t, int,
- struct ucred *, struct buf **));
-int meta_bread __P((struct vnode *, daddr_t, int,
- struct ucred *, struct buf **));
-int breada __P((struct vnode *, daddr_t, int, daddr_t, int,
- struct ucred *, struct buf **));
-int breadn __P((struct vnode *, daddr_t, int, daddr_t *, int *, int,
- struct ucred *, struct buf **));
-void brelse __P((struct buf *));
-void bremfree __P((struct buf *));
-void bufinit __P((void));
-int bwrite __P((struct buf *));
-struct buf *getblk __P((struct vnode *, daddr_t, int, int, int, int));
-struct buf *geteblk __P((int));
-struct buf *incore __P((struct vnode *, daddr_t));
-u_int minphys __P((struct buf *bp));
-int physio __P((void (*)(struct buf *), struct buf *, dev_t, int , u_int (*)(struct buf *), struct uio *, int ));
-int count_busy_buffers __P((void));
-struct buf *alloc_io_buf __P((struct vnode *vp));
-void free_io_buf __P((struct buf *bp));
-__END_DECLS
+/*!
+ * @function buf_geteblk
+ * @abstract Get a metadata buffer which is marked invalid and not associated with any vnode.
+ * @discussion A buffer is returned with zone-allocated storage of the specified size, marked B_META and invalid.
+ * It has no vnode and is not visible in the buffer hash.
+ * @param size Size of buffer.
+ * @return Always returns a new buffer.
+ */
+buf_t buf_geteblk(int size);
+
+/*!
+ * @function buf_clear_redundancy_flags
+ * @abstract Clear flags on a buffer.
+ * @discussion buffer_redundancy_flags &= ~flags
+ * @param bp Buffer whose flags to clear.
+ * @param flags Flags to remove from buffer's mask
+ */
+void buf_clear_redundancy_flags(buf_t bp, uint32_t flags);
+
+/*!
+ * @function buf_redundancyflags
+ * @abstract Get redundancy flags set on a buffer.
+ * @param bp Buffer whose redundancy flags to grab.
+ * @return flags.
+ */
+uint32_t buf_redundancy_flags(buf_t bp);
+
+/*!
+ * @function buf_setredundancyflags
+ * @abstract Set redundancy flags on a buffer.
+ * @discussion buffer_redundancy_flags |= flags
+ * @param bp Buffer whose flags to set.
+ * @param flags Flags to add to buffer's redundancy flags
+ */
+void buf_set_redundancy_flags(buf_t bp, uint32_t flags);
+
+/*!
+ * @function buf_attr
+ * @abstract Gets the attributes for this buf.
+ * @param bp Buffer whose attributes to get.
+ * @return bufattr_t.
+ */
+bufattr_t buf_attr(buf_t bp);
+
+/*!
+ * @function buf_markstatic
+ * @abstract Mark a buffer as being likely to contain static data.
+ * @param bp Buffer to mark.
+ */
+void buf_markstatic(buf_t bp);
+
+/*!
+ * @function buf_static
+ * @abstract Check if a buffer contains static data.
+ * @param bp Buffer to test.
+ * @return Nonzero if buffer has static data, 0 otherwise.
+ */
+int buf_static(buf_t bp);
+
+/*!
+ * @function bufattr_markiosched
+ * @abstract Mark a buffer as belonging to an io scheduled mount point
+ * @param bap Buffer attributes to mark.
+ * @discussion Marks the buffer so that spec_strategy() will know that it belongs to an io scheduled mount point
+ */
+void bufattr_markioscheduled(bufattr_t bap);
+
+/*!
+ * @function bufattr_iosched
+ * @abstract Check if a buffer is marked as io scheduled
+ * @param bap Buffer attributes to test.
+ * @return Nonzero if the buffer is marked io scheduled, 0 otherwise.
+ */
+int bufattr_ioscheduled(bufattr_t bap);
+
+#ifdef KERNEL_PRIVATE
+void buf_setfilter(buf_t, void (*)(buf_t, void *), void *, void(**)(buf_t, void *), void **);
+
+/* bufattr allocation/duplication/deallocation functions */
+bufattr_t bufattr_alloc(void);
+bufattr_t bufattr_dup(bufattr_t bap);
+void bufattr_free(bufattr_t bap);
+
+/*!
+ * @function bufattr_cpx
+ * @abstract Returns a pointer to a cpx_t structure.
+ * @param bap Buffer Attribute whose cpx_t structure you wish to get.
+ * @return Returns a cpx_t structure, or NULL if not valid
+ */
+struct cpx *bufattr_cpx(bufattr_t bap);
+
+/*!
+ * @function bufattr_setcpx
+ * @abstract Set the cp_ctx on a buffer attribute.
+ * @param bap Buffer Attribute that you wish to change
+ */
+void bufattr_setcpx(bufattr_t bap, struct cpx *cpx);
+
+/*!
+ * @function bufattr_cpoff
+ * @abstract Gets the file offset on the buffer.
+ * @param bap Buffer Attribute whose file offset value is used
+ */
+uint64_t bufattr_cpoff(bufattr_t bap);
+
+/*!
+ * @function bufattr_setcpoff
+ * @abstract Set the file offset for a content protected I/O on
+ * a buffer attribute.
+ * @param bap Buffer Attribute whose cp file offset has to be set
+ */
+void bufattr_setcpoff(bufattr_t bap, uint64_t);
+
+/*!
+ * @function bufattr_rawencrypted
+ * @abstract Check if a buffer contains raw encrypted data.
+ * @param bap Buffer attribute to test.
+ * @return Nonzero if buffer has raw encrypted data, 0 otherwise.
+ */
+int bufattr_rawencrypted(bufattr_t bap);
+
+/*!
+ * @function bufattr_markgreedymode
+ * @abstract Mark a buffer to use the greedy mode for writing.
+ * @param bap Buffer attributes to mark.
+ * @discussion Greedy Mode: request improved write performance from the underlying device at the expense of storage efficiency
+ */
+void bufattr_markgreedymode(bufattr_t bap);
+
+/*!
+ * @function bufattr_greedymode
+ * @abstract Check if a buffer is written using the Greedy Mode
+ * @param bap Buffer attributes to test.
+ * @discussion Greedy Mode: request improved write performance from the underlying device at the expense of storage efficiency
+ * @return Nonzero if buffer uses greedy mode, 0 otherwise.
+ */
+int bufattr_greedymode(bufattr_t bap);
+
+/*!
+ * @function bufattr_markisochronous
+ * @abstract Mark a buffer to use the isochronous throughput mode for writing.
+ * @param bap Buffer attributes to mark.
+ * @discussion isochronous mode: request improved write performance from the underlying device at the expense of storage efficiency
+ */
+void bufattr_markisochronous(bufattr_t bap);
+
+/*!
+ * @function bufattr_isochronous
+ * @abstract Check if a buffer is written using the isochronous
+ * @param bap Buffer attributes to test.
+ * @discussion isochronous mode: request improved write performance from the underlying device at the expense of storage efficiency
+ * @return Nonzero if buffer uses isochronous mode, 0 otherwise.
+ */
+int bufattr_isochronous(bufattr_t bap);
+
+
+/*!
+ * @function bufattr_throttled
+ * @abstract Check if a buffer is throttled.
+ * @param bap Buffer attribute to test.
+ * @return Nonzero if the buffer is throttled, 0 otherwise.
+ */
+int bufattr_throttled(bufattr_t bap);
+
+/*!
+ * @function bufattr_passive
+ * @abstract Check if a buffer is marked passive.
+ * @param bap Buffer attribute to test.
+ * @return Nonzero if the buffer is marked passive, 0 otherwise.
+ */
+int bufattr_passive(bufattr_t bap);
+
+/*!
+ * @function bufattr_nocache
+ * @abstract Check if a buffer has nocache attribute.
+ * @param bap Buffer attribute to test.
+ * @return Nonzero if the buffer is not cached, 0 otherwise.
+ */
+int bufattr_nocache(bufattr_t bap);
+
+/*!
+ * @function bufattr_meta
+ * @abstract Check if a buffer has the bufattr meta attribute.
+ * @param bap Buffer attribute to test.
+ * @return Nonzero if the buffer has meta attribute, 0 otherwise.
+ */
+
+int bufattr_meta(bufattr_t bap);
+
+/*!
+ * @function bufattr_markmeta
+ * @abstract Set the bufattr meta attribute.
+ * @param bap Buffer attribute to manipulate.
+ */
+void bufattr_markmeta(bufattr_t bap);
+
+
+/*!
+ * @function bufattr_delayidlesleep
+ * @abstract Check if a buffer is marked to delay idle sleep on disk IO.
+ * @param bap Buffer attribute to test.
+ * @return Nonzero if the buffer is marked to delay idle sleep on disk IO, 0 otherwise.
+ */
+int bufattr_delayidlesleep(bufattr_t bap);
+
+/*!
+ * @function buf_kernel_addrperm_addr
+ * @abstract Obfuscate the buf pointers.
+ * @param addr Buf_t pointer.
+ * @return Obfuscated pointer if addr is non zero, 0 otherwise.
+ */
+vm_offset_t buf_kernel_addrperm_addr(void * addr);
+
+/*!
+ * @function bufattr_markquickcomplete
+ * @abstract Mark a buffer to hint quick completion to the driver.
+ * @discussion This flag hints the storage driver that some thread is waiting for this I/O to complete.
+ * It should therefore attempt to complete it as soon as possible at the cost of device efficiency.
+ * @param bap Buffer attributes to mark.
+ */
+void bufattr_markquickcomplete(bufattr_t bap);
+
+/*!
+ * @function bufattr_quickcomplete
+ * @abstract Check if a buffer is marked for quick completion
+ * @discussion This flag hints the storage driver that some thread is waiting for this I/O to complete.
+ * It should therefore attempt to complete it as soon as possible at the cost of device efficiency.
+ * @param bap Buffer attribute to test.
+ * @return Nonzero if the buffer is marked for quick completion, 0 otherwise.
+ */
+int bufattr_quickcomplete(bufattr_t bap);
+
+int count_lock_queue(void);
/*
- * Stats on usefulness of the buffer cache
- */
-struct bufstats {
- long bufs_incore; /* found incore */
- long bufs_busyincore; /* found incore. was busy */
- long bufs_vmhits; /* not incore. found in VM */
- long bufs_miss; /* not incore. not in VM */
- long bufs_sleeps; /* buffer starvation */
- long bufs_eblk; /* Calls to geteblk */
- long bufs_iobufmax; /* Max. number of IO buffers used */
- long bufs_iobufinuse; /* number of IO buffers in use */
- long bufs_iobufsleeps; /* IO buffer starvation */
-};
-
-#endif /* KERNEL */
+ * Flags for buf_acquire
+ */
+#define BAC_NOWAIT 0x01 /* Don't wait if buffer is busy */
+#define BAC_REMOVE 0x02 /* Remove from free list once buffer is acquired */
+#define BAC_SKIP_NONLOCKED 0x04 /* Don't return LOCKED buffers */
+#define BAC_SKIP_LOCKED 0x08 /* Only return LOCKED buffers */
+
+errno_t buf_acquire(buf_t, int, int, int);
+
+buf_t buf_create_shadow_priv(buf_t bp, boolean_t force_copy, uintptr_t external_storage, void (*iodone)(buf_t, void *), void *arg);
+
+void buf_drop(buf_t);
+
+#endif /* KERNEL_PRIVATE */
+
+__END_DECLS
+
+
+/* Macros to clear/set/test flags. */
+#define SET(t, f) (t) |= (f)
+#define CLR(t, f) (t) &= ~(f)
+#define ISSET(t, f) ((t) & (f))
+
+
#endif /* !_SYS_BUF_H_ */
projects / apple / xnu.git / blobdiff