X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/2d21ac55c334faf3a56e5634905ed6987fc787d4..f427ee49d309d8fc33ebf3042c3a775f2f530ded:/bsd/sys/buf.h diff --git a/bsd/sys/buf.h b/bsd/sys/buf.h index 5cb9c7f9c..f46094803 100644 --- a/bsd/sys/buf.h +++ b/bsd/sys/buf.h @@ -1,8 +1,8 @@ /* - * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved. + * Copyright (c) 2000-2016 Apple Computer, Inc. All rights reserved. * * @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 @@ -11,10 +11,10 @@ * 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, @@ -22,7 +22,7 @@ * 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 */ @@ -67,26 +67,32 @@ */ #ifndef _SYS_BUF_H_ -#define _SYS_BUF_H_ +#define _SYS_BUF_H_ #include #include +#include #include -#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_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 */ + /* * make sure to check when adding flags that * that the new flags don't overlap the definitions @@ -95,380 +101,1123 @@ __BEGIN_DECLS -/* - * mark the buffer associated with buf_t - * as AGED with respect to the LRU cache +/*! + * @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); +void buf_markaged(buf_t bp); -/* - * mark the buffer associated with buf_t - * as invalid... on release, it will go - * directly to the free list +/*! + * @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); - -/* - * mark the buffer assoicated with buf_t - * as a delayed write... +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); +void buf_markdelayed(buf_t bp); -/* - * mark the buffer associated with buf_t - * as having been interrupted... EINTR - */ -void buf_markeintr(buf_t); +void buf_markclean(buf_t); -/* - * mark the buffer associated with buf_t - * for write through disk cache if device supports +/*! + * @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_markfua(buf_t); +void buf_markeintr(buf_t bp); -/* - * returns 1 if the buffer associated with buf_t - * is set for write through disk cache... 0 if it does not +/*! + * @function buf_markfua + * @abstract Mark a buffer for write through disk cache, if disk supports it. + * @param bp Buffer to mark. */ -int buf_fua(buf_t); +void buf_markfua(buf_t bp); -/* - * returns 1 if the buffer associated with buf_t - * contains valid data... 0 if it does not +/*! + * @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_valid(buf_t); +int buf_fua(buf_t bp); -/* - * returns 1 if the buffer was already valid - * in the cache... i.e. no I/O was performed - * returns 0 otherwise +/*! + * @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_fromcache(buf_t); - -/* - * returns the UPL associated with buf_t +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. */ -void * buf_upl(buf_t); - -/* - * returns the offset into the UPL - * associated with buf_t which is to be - * used as the base offset for this I/O +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. */ -uint32_t buf_uploffset(buf_t); - -/* - * returns read credential associated with buf_t - * a reference is taken which must be explicilty dropped +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. */ -ucred_t buf_rcred(buf_t); - -/* - * returns write credential associated with buf_t - * a reference is taken which must be explicilty dropped +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. */ -ucred_t buf_wcred(buf_t); - -/* - * returns process handle associated with buf_t - * i.e identity of task that issued the I/O +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. */ -proc_t buf_proc(buf_t); - -uint32_t buf_dirtyoff(buf_t); -uint32_t buf_dirtyend(buf_t); -void buf_setdirtyoff(buf_t, uint32_t); -void buf_setdirtyend(buf_t, uint32_t); - -/* - * return the errno value associated with buf_t +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. */ -errno_t buf_error(buf_t); - -/* - * set errno on buf_t +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). */ -void buf_seterror(buf_t, errno_t); +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); -/* - * set specified flags on buf_t - * B_LOCKED/B_NOCACHE/B_ASYNC/B_READ/B_WRITE/B_PAGEIO/B_FUA +/*! + * @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_setflags(buf_t, int32_t); +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); -/* - * clear specified flags on buf_t - * B_LOCKED/B_NOCACHE/B_ASYNC/B_READ/B_WRITE/B_PAGEIO/B_FUA +/*! + * @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_clearflags(buf_t, int32_t); +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); -/* - * return external flags associated with buf_t - * B_CLUSTER/B_PHYS/B_LOCKED/B_DELWRI/B_ASYNC/B_READ/B_WRITE/B_META/B_PAGEIO/B_FUA +/*! + * @function buf_setdrvdata + * @abstract Set driver-specific data on a buffer. + * @param bp Buffer whose driver-data to set. + * @param drvdata Opaque driver data. */ -int32_t buf_flags(buf_t); +void buf_setdrvdata(buf_t bp, void *drvdata); -/* - * clears I/O related flags (both internal and - * external) associated with buf_t and allows - * the following to be set... - * B_READ/B_WRITE/B_ASYNC/B_NOCACHE +/*! + * @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_reset(buf_t, int32_t); +void * buf_drvdata(buf_t bp); -/* - * insure that the data storage associated with buf_t - * is addressable +/*! + * @function buf_setfsprivate + * @abstract Set filesystem-specific data on a buffer. + * @param bp Buffer whose filesystem data to set. + * @param fsprivate Opaque filesystem data. */ -errno_t buf_map(buf_t, caddr_t *); +void buf_setfsprivate(buf_t bp, void *fsprivate); -/* - * release our need to have the storage associated - * with buf_t in an addressable state +/*! + * @function buf_fsprivate + * @abstract Get filesystem-specific data from a buffer. + * @param bp Buffer whose filesystem data to get. + * @return Opaque filesystem data. */ -errno_t buf_unmap(buf_t); +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); -/* - * set driver specific data for buf_t +/*! + * @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. */ -void buf_setdrvdata(buf_t, void *); +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); -/* - * retrieve driver specific data associated with buf_t +/*! + * @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_drvdata(buf_t); +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); /* - * set fs specific data for buf_t + * Flags for buf_invalblkno() + */ +#define BUF_WAIT 0x01 + +/*! + * @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); + +/*! + * @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. */ -void buf_setfsprivate(buf_t, void *); -/* - * retrieve driver specific data associated with buf_t +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. */ -void * buf_fsprivate(buf_t); +int buf_shadow(buf_t bp); -/* - * retrieve the phsyical block number associated with buf_t + +/*! + * @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. */ -daddr64_t buf_blkno(buf_t); +buf_t buf_alloc(vnode_t vp); -/* - * retrieve the logical block number associated with buf_t - * i.e. the block number derived from the file offset +/*! + * @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. */ -daddr64_t buf_lblkno(buf_t); +void buf_free(buf_t bp); /* - * set the phsyical block number associated with buf_t + * 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(). */ -void buf_setblkno(buf_t, daddr64_t); +int buf_invalidateblks(vnode_t vp, int flags, int slpflag, int slptimeo); /* - * set the logical block number associated with buf_t - * i.e. the block number derived from the file offset + * 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(). */ -void buf_setlblkno(buf_t, daddr64_t); +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); + /* - * retrieve the count of valid bytes associated with buf_t + * Flags for operation type in getblk() */ -uint32_t buf_count(buf_t); - +#define BLK_READ 0x01 /* buffer for read */ +#define BLK_WRITE 0x02 /* buffer for write */ +#define BLK_META 0x10 /* buffer for metadata */ /* - * retrieve the size of the data store assoicated with buf_t + * 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 + +/*! + * @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. */ -uint32_t buf_size(buf_t); +buf_t buf_getblk(vnode_t vp, daddr64_t blkno, int size, int slpflag, int slptimeo, int operation); + +/*! + * @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); -/* - * retrieve the residual I/O count assoicated with buf_t - * i.e. number of bytes that have not yet been completed +/*! + * @function buf_redundancyflags + * @abstract Get redundancy flags set on a buffer. + * @param bp Buffer whose redundancy flags to grab. + * @return flags. */ -uint32_t buf_resid(buf_t); +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); -/* - * set the count of bytes associated with buf_t - * typically used to set the size of the I/O to be performed +/*! + * @function buf_attr + * @abstract Gets the attributes for this buf. + * @param bp Buffer whose attributes to get. + * @return bufattr_t. */ -void buf_setcount(buf_t, uint32_t); +bufattr_t buf_attr(buf_t bp); -/* - * set the size of the buffer store associated with buf_t - * typically used when providing private storage to buf_t +/*! + * @function buf_markstatic + * @abstract Mark a buffer as being likely to contain static data. + * @param bp Buffer to mark. */ -void buf_setsize(buf_t, uint32_t); +void buf_markstatic(buf_t bp); -/* - * set the size in bytes of the unfinished I/O associated with buf_t +/*! + * @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. */ -void buf_setresid(buf_t, uint32_t); +int buf_static(buf_t bp); -/* - * associate kernel addressable storage with buf_t +/*! + * @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 buf_setdataptr(buf_t, uintptr_t); +void bufattr_markioscheduled(bufattr_t bap); -/* - * retrieve pointer to buffer associated with buf_t - * if non-null, than guaranteed to be kernel addressable - * size of buffer can be retrieved via buf_size - * size of valid data can be retrieved via buf_count - * if NULL, than use buf_map/buf_unmap to manage access to the underlying storage +/*! + * @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. */ -uintptr_t buf_dataptr(buf_t); +int bufattr_ioscheduled(bufattr_t bap); -/* - * return the vnode_t associated with buf_t +#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 */ -vnode_t buf_vnode(buf_t); +struct cpx *bufattr_cpx(bufattr_t bap); -/* - * assign vnode_t to buf_t... the - * device currently associated with - * but_t is not changed. +/*! + * @function bufattr_setcpx + * @abstract Set the cp_ctx on a buffer attribute. + * @param bap Buffer Attribute that you wish to change */ -void buf_setvnode(buf_t, vnode_t); +void bufattr_setcpx(bufattr_t bap, struct cpx *cpx); -/* - * return the dev_t associated with buf_t +/*! + * @function bufattr_cpoff + * @abstract Gets the file offset on the buffer. + * @param bap Buffer Attribute whose file offset value is used */ -dev_t buf_device(buf_t); +uint64_t bufattr_cpoff(bufattr_t bap); -/* - * assign the dev_t associated with vnode_t - * to buf_t +/*! + * @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 */ -errno_t buf_setdevice(buf_t, vnode_t); +void bufattr_setcpoff(bufattr_t bap, uint64_t); -errno_t buf_strategy(vnode_t, void *); +/*! + * @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); -/* - * flags for buf_invalblkno +/*! + * @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. */ -#define BUF_WAIT 0x01 +int bufattr_greedymode(bufattr_t bap); -errno_t buf_invalblkno(vnode_t, daddr64_t, int); +/*! + * @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); -/* - * return the callback function pointer - * if the callback is still valid - * returns NULL if a buffer that was not - * allocated via buf_alloc is specified - * or if a callback has not been set or - * it has already fired... +/*! + * @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. */ -void * buf_callback(buf_t); +int bufattr_throttled(bufattr_t bap); -/* - * assign a one-shot callback function (driven from biodone) - * to a buf_t allocated via buf_alloc... a caller specified - * arg is passed to the callback function +/*! + * @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. */ -errno_t buf_setcallback(buf_t, void (*)(buf_t, void *), void *); +int bufattr_passive(bufattr_t bap); -/* - * add a upl_t to a buffer allocated via buf_alloc - * and set the offset into the upl_t (must be page - * aligned). +/*! + * @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. */ -errno_t buf_setupl(buf_t, upl_t, uint32_t); +int bufattr_nocache(bufattr_t bap); -/* - * allocate a buf_t that is a clone of the buf_t - * passed in, but whose I/O range is a subset... - * if a callback routine is specified, it will - * be called from buf_biodone with the bp and - * arg specified. - * it must be freed via buf_free +/*! + * @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. */ -buf_t buf_clone(buf_t, int, int, void (*)(buf_t, void *), void *); -/* - * allocate a buf_t associated with vnode_t - * that has NO storage associated with it - * but is suitable for use in issuing I/Os - * after storage has been assigned via buf_setdataptr - * or buf_addupl - */ -buf_t buf_alloc(vnode_t); +int bufattr_meta(bufattr_t bap); -/* - * free a buf_t that was allocated via buf_alloc - * any private storage associated with buf_t is the - * responsiblity of the caller to release +/*! + * @function bufattr_markmeta + * @abstract Set the bufattr meta attribute. + * @param bap Buffer attribute to manipulate. */ -void buf_free(buf_t); +void bufattr_markmeta(bufattr_t bap); -/* - * flags for buf_invalidateblks - */ -#define BUF_WRITE_DATA 0x0001 /* write data blocks first */ -#define BUF_SKIP_META 0x0002 /* skip over metadata blocks */ -int buf_invalidateblks(vnode_t, int, int, int); -/* - * flags for buf_flushdirtyblks and buf_iterate +/*! + * @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. */ -#define BUF_SKIP_NONLOCKED 0x01 -#define BUF_SKIP_LOCKED 0x02 -#define BUF_SCAN_CLEAN 0x04 /* scan only the clean buffers */ -#define BUF_SCAN_DIRTY 0x08 /* scan only the dirty buffers */ -#define BUF_NOTIFY_BUSY 0x10 /* notify the caller about the busy pages during the scan */ +int bufattr_delayidlesleep(bufattr_t bap); -void buf_flushdirtyblks(vnode_t, int, int, const char *); -void buf_iterate(vnode_t, int (*)(buf_t, void *), int, void *); +/*! + * @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); -#define BUF_RETURNED 0 -#define BUF_RETURNED_DONE 1 -#define BUF_CLAIMED 2 -#define BUF_CLAIMED_DONE 3 +int count_lock_queue(void); /* - * zero the storage associated with buf_t + * Flags for buf_acquire */ -void buf_clear(buf_t); - -errno_t buf_bawrite(buf_t); -errno_t buf_bdwrite(buf_t); -errno_t buf_bwrite(buf_t); +#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 */ -void buf_biodone(buf_t); -errno_t buf_biowait(buf_t); -void buf_brelse(buf_t); +errno_t buf_acquire(buf_t, int, int, int); -errno_t buf_bread(vnode_t, daddr64_t, int, ucred_t, buf_t *); -errno_t buf_breadn(vnode_t, daddr64_t, int, daddr64_t *, int *, int, ucred_t, buf_t *); -errno_t buf_meta_bread(vnode_t, daddr64_t, int, ucred_t, buf_t *); -errno_t buf_meta_breadn(vnode_t, daddr64_t, int, daddr64_t *, int *, int, ucred_t, buf_t *); +buf_t buf_create_shadow_priv(buf_t bp, boolean_t force_copy, uintptr_t external_storage, void (*iodone)(buf_t, void *), void *arg); -u_int minphys(buf_t bp); -int physio(void (*)(buf_t), buf_t, dev_t, int , u_int (*)(buf_t), struct uio *, int ); +void buf_drop(buf_t); - -/* - * Flags for operation type in getblk() - */ -#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 - -/* timeout is in msecs */ -buf_t buf_getblk(vnode_t, daddr64_t, int, int, int, int); -buf_t buf_geteblk(int); +#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)) +#define SET(t, f) (t) |= (f) +#define CLR(t, f) (t) &= ~(f) +#define ISSET(t, f) ((t) & (f)) #endif /* !_SYS_BUF_H_ */