[dragonfly.git] / sys / vfs / ufs / ffs_rawread.c

/*-
 * Copyright (c) 2000-2003 Tor Egge
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD: src/sys/ufs/ffs/ffs_rawread.c,v 1.3.2.2 2003/05/29 06:15:35 alc Exp $
 * $DragonFly: src/sys/vfs/ufs/ffs_rawread.c,v 1.28 2008/06/19 23:27:39 dillon Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/proc.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/conf.h>
#include <sys/filio.h>
#include <sys/ttycom.h>
#include <sys/buf.h>
#include "quota.h"
#include "inode.h"
#include "fs.h"

#include <machine/limits.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_object.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>

static int ffs_rawread_readahead(struct vnode *vp, caddr_t udata, off_t offset,
				 size_t len, struct buf *bp, int *baseticks);
static int ffs_rawread_main(struct vnode *vp,
			    struct uio *uio);

static int ffs_rawread_sync(struct vnode *vp);

int ffs_rawread(struct vnode *vp, struct uio *uio, int *workdone);

void ffs_rawread_setup(void);

SYSCTL_DECL(_vfs_ffs);

static int ffsrawbufcnt = 4;
SYSCTL_INT(_vfs_ffs, OID_AUTO, ffsrawbufcnt, CTLFLAG_RD, &ffsrawbufcnt, 0,
	   "Buffers available for raw reads");

static int allowrawread = 1;
SYSCTL_INT(_vfs_ffs, OID_AUTO, allowrawread, CTLFLAG_RW, &allowrawread, 0,
	   "Flag to enable raw reads");

static int rawreadahead = 1;
SYSCTL_INT(_vfs_ffs, OID_AUTO, rawreadahead, CTLFLAG_RW, &rawreadahead, 0,
	   "Flag to enable readahead for long raw reads");


void
ffs_rawread_setup(void)
{
	ffsrawbufcnt = (nswbuf > 100 ) ? (nswbuf - (nswbuf >> 4)) : nswbuf - 8;
}


static int
ffs_rawread_sync(struct vnode *vp)
{
	int error;
	int upgraded;

	/*
	 * Check for dirty mmap, pending writes and dirty buffers
	 */
	lwkt_gettoken(&vp->v_token);
	if (bio_track_active(&vp->v_track_write) ||
	    !RB_EMPTY(&vp->v_rbdirty_tree) ||
	    (vp->v_flag & VOBJDIRTY) != 0) {
		if (vn_islocked(vp) != LK_EXCLUSIVE) {
			upgraded = 1;
			/* Upgrade to exclusive lock, this might block */
			vn_lock(vp, LK_UPGRADE);
		} else
			upgraded = 0;
		
		/* Attempt to msync mmap() regions to clean dirty mmap */ 
		if ((vp->v_flag & VOBJDIRTY) != 0) {
			struct vm_object *obj;
			if ((obj = vp->v_object) != NULL)
				vm_object_page_clean(obj, 0, 0, OBJPC_SYNC);
		}

		/* Wait for pending writes to complete */
		error = bio_track_wait(&vp->v_track_write, 0, 0);
		if (error != 0) {
			if (upgraded != 0)
				vn_lock(vp, LK_DOWNGRADE);
			goto done;
		}
		/* Flush dirty buffers */
		if (!RB_EMPTY(&vp->v_rbdirty_tree)) {
			if ((error = VOP_FSYNC(vp, MNT_WAIT, 0)) != 0) {
				if (upgraded != 0)
					vn_lock(vp, LK_DOWNGRADE);
				goto done;
			}
			if (bio_track_active(&vp->v_track_write) ||
			    !RB_EMPTY(&vp->v_rbdirty_tree))
				panic("ffs_rawread_sync: dirty bufs");
		}
		if (upgraded != 0)
			vn_lock(vp, LK_DOWNGRADE);
	} else {
		error = 0;
	}
done:
	lwkt_reltoken(&vp->v_token);
	return error;
}


static int
ffs_rawread_readahead(struct vnode *vp, caddr_t udata, off_t loffset,
		      size_t len, struct buf *bp, int *baseticks)
{
	int error;
	int iolen;
	int blockoff;
	int bsize;
	struct vnode *dp;
	int bforwards;
	
	bsize = vp->v_mount->mnt_stat.f_iosize;

	/*
	 * Make sure it fits into the pbuf
	 */
	iolen = (int)(intptr_t)udata & PAGE_MASK;
	if (len + iolen > bp->b_kvasize) {
		len = bp->b_kvasize;
		if (iolen != 0)
			len -= PAGE_SIZE;
	}

	/*
	 * Raw disk address is in bio2, but we wait for it to
	 * chain to bio1.
	 */
	bp->b_flags &= ~B_ERROR;
	bp->b_loffset = loffset;
	bp->b_bio2.bio_offset = NOOFFSET;
	bp->b_bio1.bio_done = biodone_sync;
	bp->b_bio1.bio_flags |= BIO_SYNC;

	blockoff = (loffset % bsize) / DEV_BSIZE;

	error = VOP_BMAP(vp, bp->b_loffset, &bp->b_bio2.bio_offset,
			 &bforwards, NULL, BUF_CMD_READ);
	if (error != 0)
		return error;
	dp = VTOI(vp)->i_devvp;
	if (bp->b_bio2.bio_offset == NOOFFSET) {
		/* 
		 * Fill holes with NULs to preserve semantics 
		 */
		if (len + blockoff * DEV_BSIZE > bsize)
			len = bsize - blockoff * DEV_BSIZE;
		
		if (vmapbuf(bp, udata, len) < 0)
			return EFAULT;
		
		if (ticks - *baseticks >= hogticks) {
			*baseticks = ticks;
			uio_yield();
		}
		bzero(bp->b_data, bp->b_bcount);

		/* Mark operation completed (similar to bufdone()) */

		bp->b_resid = 0;
		return 0;
	}
	
	if (len + blockoff * DEV_BSIZE > bforwards)
		len = bforwards - blockoff * DEV_BSIZE;
	bp->b_bio2.bio_offset += blockoff * DEV_BSIZE;
	
	if (vmapbuf(bp, udata, len) < 0)
		return EFAULT;
	
	/*
	 * Access the block device layer using the device vnode (dp) and
	 * the translated block number (bio2) instead of the logical block
	 * number (bio1).
	 *
	 * Even though we are bypassing the vnode layer, we still
	 * want the vnode state to indicate that an I/O on its behalf
	 * is in progress.
	 */
	bp->b_cmd = BUF_CMD_READ;
	bio_start_transaction(&bp->b_bio1, &vp->v_track_read);
	vn_strategy(dp, &bp->b_bio2);
	return 0;
}

static int
ffs_rawread_main(struct vnode *vp, struct uio *uio)
{
	int error, nerror;
	struct buf *bp, *nbp, *tbp;
	int iolen;
	int baseticks = ticks;
	caddr_t udata;
	int resid;
	off_t offset;
	
	udata = uio->uio_iov->iov_base;
	resid = uio->uio_resid;
	offset = uio->uio_offset;

	error = 0;
	nerror = 0;
	
	bp = NULL;
	nbp = NULL;
	
	while (resid > 0) {
		
		if (bp == NULL) { /* Setup first read */
			/* XXX: Leave some bufs for swap */
			bp = getpbuf(&ffsrawbufcnt);
			error = ffs_rawread_readahead(vp, udata, offset, resid,
						      bp, &baseticks);
			if (error != 0)
				break;
			
			if (resid > bp->b_bufsize) { /* Setup fist readahead */
				/* XXX: Leave bufs for swap */
				if (rawreadahead != 0) 
					nbp = trypbuf(&ffsrawbufcnt);
				else
					nbp = NULL;
				if (nbp != NULL) {
					nerror = ffs_rawread_readahead(
							vp, 
							udata + bp->b_bufsize,
							offset + bp->b_bufsize,
							resid - bp->b_bufsize,
							nbp, &baseticks);
					if (nerror) {
						relpbuf(nbp, &ffsrawbufcnt);
						nbp = NULL;
					}
				}
			}
		}
		
		biowait(&bp->b_bio1, "rawrd");
		
		vunmapbuf(bp);
		
		iolen = bp->b_bcount - bp->b_resid;
		if (iolen == 0 && (bp->b_flags & B_ERROR) == 0) {
			nerror = 0;	/* Ignore possible beyond EOF error */
			break; /* EOF */
		}
		
		if ((bp->b_flags & B_ERROR) != 0) {
			error = bp->b_error;
			break;
		}
		clearbiocache(&bp->b_bio2);
		resid -= iolen;
		udata += iolen;
		offset += iolen;
		if (iolen < bp->b_bufsize) {
			/* Incomplete read.  Try to read remaining part */
			error = ffs_rawread_readahead(
				    vp, udata, offset,
				    bp->b_bufsize - iolen, bp, &baseticks);
			if (error != 0)
				break;
		} else if (nbp != NULL) { /* Complete read with readahead */
			
			tbp = bp;
			bp = nbp;
			nbp = tbp;
			
			clearbiocache(&nbp->b_bio2);
			
			if (resid <= bp->b_bufsize) { /* No more readaheads */
				relpbuf(nbp, &ffsrawbufcnt);
				nbp = NULL;
			} else { /* Setup next readahead */
				nerror = ffs_rawread_readahead(
						vp, udata + bp->b_bufsize,
				   		offset + bp->b_bufsize,
						resid - bp->b_bufsize,
						nbp, &baseticks);
				if (nerror != 0) {
					relpbuf(nbp, &ffsrawbufcnt);
					nbp = NULL;
				}
			}
		} else if (nerror != 0) {/* Deferred Readahead error */
			break;		
		}  else if (resid > 0) { /* More to read, no readahead */
			error = ffs_rawread_readahead(vp, udata, offset,
						      resid, bp,
						      &baseticks);
			if (error != 0)
				break;
		}
	}
	
	if (bp != NULL)
		relpbuf(bp, &ffsrawbufcnt);
	if (nbp != NULL) {			/* Run down readahead buffer */
		biowait(&nbp->b_bio1, "rawrd");
		vunmapbuf(nbp);
		relpbuf(nbp, &ffsrawbufcnt);
	}
	
	if (error == 0)
		error = nerror;
	uio->uio_iov->iov_base = udata;
	uio->uio_resid = resid;
	uio->uio_offset = offset;
	return error;
}


int
ffs_rawread(struct vnode *vp,
	    struct uio *uio,
	    int *workdone)
{
	if (allowrawread != 0 &&
	    uio->uio_iovcnt == 1 && 
	    uio->uio_segflg == UIO_USERSPACE &&
	    uio->uio_resid == uio->uio_iov->iov_len &&
	    (curthread->td_flags & TDF_DEADLKTREAT) == 0) {
		int secsize;		/* Media sector size */
		off_t filebytes;	/* Bytes left of file */
		int blockbytes;		/* Bytes left of file in full blocks */
		int partialbytes;	/* Bytes in last partial block */
		int skipbytes;		/* Bytes not to read in ffs_rawread */
		struct inode *ip;
		int error;
		

		/* Only handle sector aligned reads */
		ip = VTOI(vp);
		secsize = ip->i_devvp->v_rdev->si_bsize_phys;
		if ((uio->uio_offset & (secsize - 1)) == 0 &&
		    (uio->uio_resid & (secsize - 1)) == 0) {
			
			/* Sync dirty pages and buffers if needed */
			error = ffs_rawread_sync(vp);
			if (error != 0)
				return error;
			
			/* Check for end of file */
			if (ip->i_size > uio->uio_offset) {
				filebytes = ip->i_size - uio->uio_offset;

				/* No special eof handling needed ? */
				if (uio->uio_resid <= filebytes) {
					*workdone = 1;
					return ffs_rawread_main(vp, uio);
				}
				
				partialbytes = ((unsigned int) ip->i_size) %
					ip->i_fs->fs_bsize;
				blockbytes = (int) filebytes - partialbytes;
				if (blockbytes > 0) {
					skipbytes = uio->uio_resid -
						blockbytes;
					uio->uio_resid = blockbytes;
					error = ffs_rawread_main(vp, uio);
					uio->uio_resid += skipbytes;
					if (error != 0)
						return error;
					/* Read remaining part using buffer */
				}
			}
		}
	}
	*workdone = 0;
	return 0;
}
Commit	Line	Data
984263bc MD	1	/*-
	2	* Copyright (c) 2000-2003 Tor Egge
	3	* All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	8	* 1. Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions and the following disclaimer.
	10	* 2. Redistributions in binary form must reproduce the above copyright
	11	* notice, this list of conditions and the following disclaimer in the
	12	* documentation and/or other materials provided with the distribution.
	13	*
	14	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	15	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	16	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	17	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	18	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	19	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	20	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	21	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	22	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	23	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	24	* SUCH DAMAGE.
	25	*
	26	* $FreeBSD: src/sys/ufs/ffs/ffs_rawread.c,v 1.3.2.2 2003/05/29 06:15:35 alc Exp $
e92ca23a	27	* $DragonFly: src/sys/vfs/ufs/ffs_rawread.c,v 1.28 2008/06/19 23:27:39 dillon Exp $
984263bc MD	28	*/
	29
	30	#include <sys/param.h>
	31	#include <sys/systm.h>
	32	#include <sys/fcntl.h>
	33	#include <sys/file.h>
	34	#include <sys/stat.h>
	35	#include <sys/proc.h>
	36	#include <sys/mount.h>
	37	#include <sys/namei.h>
	38	#include <sys/vnode.h>
	39	#include <sys/conf.h>
	40	#include <sys/filio.h>
	41	#include <sys/ttycom.h>
	42	#include <sys/buf.h>
1f2de5d4 MD	43	#include "quota.h"
	44	#include "inode.h"
	45	#include "fs.h"
984263bc MD	46
	47	#include <machine/limits.h>
	48	#include <vm/vm.h>
	49	#include <vm/vm_extern.h>
	50	#include <vm/vm_object.h>
	51	#include <sys/kernel.h>
	52	#include <sys/sysctl.h>
	53
2d53bf02	54	static int ffs_rawread_readahead(struct vnode *vp, caddr_t udata, off_t offset,
a11aaa81	55	size_t len, struct buf bp, int baseticks);
984263bc MD	56	static int ffs_rawread_main(struct vnode *vp,
	57	struct uio *uio);
	58
a11aaa81	59	static int ffs_rawread_sync(struct vnode *vp);
984263bc MD	60
	61	int ffs_rawread(struct vnode vp, struct uio uio, int *workdone);
	62
	63	void ffs_rawread_setup(void);
	64
984263bc MD	65	SYSCTL_DECL(_vfs_ffs);
	66
	67	static int ffsrawbufcnt = 4;
	68	SYSCTL_INT(_vfs_ffs, OID_AUTO, ffsrawbufcnt, CTLFLAG_RD, &ffsrawbufcnt, 0,
	69	"Buffers available for raw reads");
	70
	71	static int allowrawread = 1;
	72	SYSCTL_INT(_vfs_ffs, OID_AUTO, allowrawread, CTLFLAG_RW, &allowrawread, 0,
	73	"Flag to enable raw reads");
	74
	75	static int rawreadahead = 1;
	76	SYSCTL_INT(_vfs_ffs, OID_AUTO, rawreadahead, CTLFLAG_RW, &rawreadahead, 0,
	77	"Flag to enable readahead for long raw reads");
	78
	79
	80	void
	81	ffs_rawread_setup(void)
	82	{
	83	ffsrawbufcnt = (nswbuf > 100 ) ? (nswbuf - (nswbuf >> 4)) : nswbuf - 8;
	84	}
	85
	86
	87	static int
a11aaa81	88	ffs_rawread_sync(struct vnode *vp)
984263bc	89	{
984263bc MD	90	int error;
	91	int upgraded;
	92
0202303b MD	93	/*
	94	* Check for dirty mmap, pending writes and dirty buffers
	95	*/
3b998fa9	96	lwkt_gettoken(&vp->v_token);
a9a20f98	97	if (bio_track_active(&vp->v_track_write) \|\|
6bae6177	98	!RB_EMPTY(&vp->v_rbdirty_tree) \|\|
984263bc	99	(vp->v_flag & VOBJDIRTY) != 0) {
a11aaa81	100	if (vn_islocked(vp) != LK_EXCLUSIVE) {
984263bc MD	101	upgraded = 1;
984263bc MD	102	/* Upgrade to exclusive lock, this might block */
a11aaa81	103	vn_lock(vp, LK_UPGRADE);
984263bc MD	104	} else
	105	upgraded = 0;
	106
	107	/* Attempt to msync mmap() regions to clean dirty mmap */
	108	if ((vp->v_flag & VOBJDIRTY) != 0) {
	109	struct vm_object *obj;
7540ab49	110	if ((obj = vp->v_object) != NULL)
984263bc MD	111	vm_object_page_clean(obj, 0, 0, OBJPC_SYNC);
	112	}
	113
	114	/* Wait for pending writes to complete */
a9a20f98 MD	115	error = bio_track_wait(&vp->v_track_write, 0, 0);
a9a20f98 MD	116	if (error != 0) {
a9a20f98 MD	117	if (upgraded != 0)
a9a20f98 MD	118	vn_lock(vp, LK_DOWNGRADE);
0202303b	119	goto done;
984263bc MD	120	}
984263bc MD	121	/* Flush dirty buffers */
6bae6177	122	if (!RB_EMPTY(&vp->v_rbdirty_tree)) {
52174f71	123	if ((error = VOP_FSYNC(vp, MNT_WAIT, 0)) != 0) {
984263bc	124	if (upgraded != 0)
a11aaa81	125	vn_lock(vp, LK_DOWNGRADE);
0202303b	126	goto done;
984263bc	127	}
a9a20f98	128	if (bio_track_active(&vp->v_track_write) \|\|
6bae6177	129	!RB_EMPTY(&vp->v_rbdirty_tree))
984263bc MD	130	panic("ffs_rawread_sync: dirty bufs");
984263bc MD	131	}
984263bc	132	if (upgraded != 0)
a11aaa81	133	vn_lock(vp, LK_DOWNGRADE);
984263bc	134	} else {
0202303b	135	error = 0;
984263bc	136	}
0202303b	137	done:
3b998fa9	138	lwkt_reltoken(&vp->v_token);
0202303b	139	return error;
984263bc MD	140	}
	141
	142
	143	static int
81b5c339	144	ffs_rawread_readahead(struct vnode *vp, caddr_t udata, off_t loffset,
a11aaa81	145	size_t len, struct buf bp, int baseticks)
984263bc MD	146	{
984263bc MD	147	int error;
3591bbc6	148	int iolen;
984263bc MD	149	int blockoff;
	150	int bsize;
	151	struct vnode *dp;
	152	int bforwards;
	153
	154	bsize = vp->v_mount->mnt_stat.f_iosize;
3591bbc6 MD	155
	156	/*
	157	* Make sure it fits into the pbuf
	158	*/
	159	iolen = (int)(intptr_t)udata & PAGE_MASK;
	160	if (len + iolen > bp->b_kvasize) {
	161	len = bp->b_kvasize;
984263bc	162	if (iolen != 0)
3591bbc6	163	len -= PAGE_SIZE;
984263bc	164	}
ae8e83e6 MD	165
	166	/*
	167	* Raw disk address is in bio2, but we wait for it to
	168	* chain to bio1.
	169	*/
10f3fee5	170	bp->b_flags &= ~B_ERROR;
81b5c339	171	bp->b_loffset = loffset;
81b5c339	172	bp->b_bio2.bio_offset = NOOFFSET;
ae8e83e6 MD	173	bp->b_bio1.bio_done = biodone_sync;
ae8e83e6 MD	174	bp->b_bio1.bio_flags \|= BIO_SYNC;
81b5c339	175
aa73238b MD	176	blockoff = (loffset % bsize) / DEV_BSIZE;
aa73238b MD	177
08daea96	178	error = VOP_BMAP(vp, bp->b_loffset, &bp->b_bio2.bio_offset,
e92ca23a	179	&bforwards, NULL, BUF_CMD_READ);
08daea96	180	if (error != 0)
984263bc	181	return error;
08daea96	182	dp = VTOI(vp)->i_devvp;
54078292	183	if (bp->b_bio2.bio_offset == NOOFFSET) {
81b5c339 MD	184	/*
	185	* Fill holes with NULs to preserve semantics
	186	*/
3591bbc6 MD	187	if (len + blockoff * DEV_BSIZE > bsize)
3591bbc6 MD	188	len = bsize - blockoff * DEV_BSIZE;
984263bc	189
3591bbc6	190	if (vmapbuf(bp, udata, len) < 0)
984263bc MD	191	return EFAULT;
984263bc MD	192
2d53bf02 MD	193	if (ticks - *baseticks >= hogticks) {
2d53bf02 MD	194	*baseticks = ticks;
984263bc	195	uio_yield();
2d53bf02	196	}
3591bbc6	197	bzero(bp->b_data, bp->b_bcount);
984263bc MD	198
	199	/* Mark operation completed (similar to bufdone()) */
	200
	201	bp->b_resid = 0;
984263bc MD	202	return 0;
	203	}
	204
3591bbc6 MD	205	if (len + blockoff * DEV_BSIZE > bforwards)
3591bbc6 MD	206	len = bforwards - blockoff * DEV_BSIZE;
54078292	207	bp->b_bio2.bio_offset += blockoff * DEV_BSIZE;
984263bc	208
3591bbc6	209	if (vmapbuf(bp, udata, len) < 0)
984263bc MD	210	return EFAULT;
984263bc MD	211
81b5c339 MD	212	/*
	213	* Access the block device layer using the device vnode (dp) and
	214	* the translated block number (bio2) instead of the logical block
	215	* number (bio1).
	216	*
	217	* Even though we are bypassing the vnode layer, we still
	218	* want the vnode state to indicate that an I/O on its behalf
	219	* is in progress.
	220	*/
10f3fee5	221	bp->b_cmd = BUF_CMD_READ;
81b5c339 MD	222	bio_start_transaction(&bp->b_bio1, &vp->v_track_read);
81b5c339 MD	223	vn_strategy(dp, &bp->b_bio2);
984263bc MD	224	return 0;
	225	}
	226
984263bc	227	static int
2d53bf02	228	ffs_rawread_main(struct vnode vp, struct uio uio)
984263bc MD	229	{
	230	int error, nerror;
	231	struct buf bp, nbp, *tbp;
3591bbc6	232	int iolen;
2d53bf02	233	int baseticks = ticks;
984263bc	234	caddr_t udata;
54078292	235	int resid;
984263bc	236	off_t offset;
984263bc	237
984263bc MD	238	udata = uio->uio_iov->iov_base;
	239	resid = uio->uio_resid;
	240	offset = uio->uio_offset;
	241
984263bc MD	242	error = 0;
	243	nerror = 0;
	244
	245	bp = NULL;
	246	nbp = NULL;
984263bc MD	247
	248	while (resid > 0) {
	249
	250	if (bp == NULL) { /* Setup first read */
	251	/* XXX: Leave some bufs for swap */
	252	bp = getpbuf(&ffsrawbufcnt);
2d53bf02	253	error = ffs_rawread_readahead(vp, udata, offset, resid,
a11aaa81	254	bp, &baseticks);
984263bc MD	255	if (error != 0)
	256	break;
	257
	258	if (resid > bp->b_bufsize) { /* Setup fist readahead */
	259	/* XXX: Leave bufs for swap */
	260	if (rawreadahead != 0)
	261	nbp = trypbuf(&ffsrawbufcnt);
	262	else
	263	nbp = NULL;
	264	if (nbp != NULL) {
2d53bf02 MD	265	nerror = ffs_rawread_readahead(
	266	vp,
	267	udata + bp->b_bufsize,
	268	offset + bp->b_bufsize,
	269	resid - bp->b_bufsize,
a11aaa81	270	nbp, &baseticks);
984263bc MD	271	if (nerror) {
	272	relpbuf(nbp, &ffsrawbufcnt);
	273	nbp = NULL;
	274	}
	275	}
	276	}
	277	}
	278
ae8e83e6	279	biowait(&bp->b_bio1, "rawrd");
984263bc MD	280
	281	vunmapbuf(bp);
	282
	283	iolen = bp->b_bcount - bp->b_resid;
	284	if (iolen == 0 && (bp->b_flags & B_ERROR) == 0) {
	285	nerror = 0; /* Ignore possible beyond EOF error */
	286	break; /* EOF */
	287	}
	288
	289	if ((bp->b_flags & B_ERROR) != 0) {
	290	error = bp->b_error;
	291	break;
	292	}
81b5c339	293	clearbiocache(&bp->b_bio2);
984263bc MD	294	resid -= iolen;
	295	udata += iolen;
	296	offset += iolen;
	297	if (iolen < bp->b_bufsize) {
	298	/* Incomplete read. Try to read remaining part */
2d53bf02 MD	299	error = ffs_rawread_readahead(
2d53bf02 MD	300	vp, udata, offset,
a11aaa81	301	bp->b_bufsize - iolen, bp, &baseticks);
984263bc MD	302	if (error != 0)
	303	break;
	304	} else if (nbp != NULL) { /* Complete read with readahead */
	305
	306	tbp = bp;
	307	bp = nbp;
	308	nbp = tbp;
	309
81b5c339	310	clearbiocache(&nbp->b_bio2);
984263bc MD	311
	312	if (resid <= bp->b_bufsize) { /* No more readaheads */
	313	relpbuf(nbp, &ffsrawbufcnt);
	314	nbp = NULL;
	315	} else { /* Setup next readahead */
2d53bf02 MD	316	nerror = ffs_rawread_readahead(
	317	vp, udata + bp->b_bufsize,
	318	offset + bp->b_bufsize,
	319	resid - bp->b_bufsize,
a11aaa81	320	nbp, &baseticks);
984263bc MD	321	if (nerror != 0) {
	322	relpbuf(nbp, &ffsrawbufcnt);
	323	nbp = NULL;
	324	}
	325	}
	326	} else if (nerror != 0) {/* Deferred Readahead error */
	327	break;
	328	} else if (resid > 0) { /* More to read, no readahead */
	329	error = ffs_rawread_readahead(vp, udata, offset,
a11aaa81	330	resid, bp,
2d53bf02	331	&baseticks);
984263bc MD	332	if (error != 0)
	333	break;
	334	}
	335	}
	336
	337	if (bp != NULL)
	338	relpbuf(bp, &ffsrawbufcnt);
	339	if (nbp != NULL) { /* Run down readahead buffer */
ae8e83e6	340	biowait(&nbp->b_bio1, "rawrd");
984263bc MD	341	vunmapbuf(nbp);
	342	relpbuf(nbp, &ffsrawbufcnt);
	343	}
	344
	345	if (error == 0)
	346	error = nerror;
984263bc MD	347	uio->uio_iov->iov_base = udata;
	348	uio->uio_resid = resid;
	349	uio->uio_offset = offset;
	350	return error;
	351	}
	352
	353
	354	int
	355	ffs_rawread(struct vnode *vp,
	356	struct uio *uio,
	357	int *workdone)
	358	{
	359	if (allowrawread != 0 &&
	360	uio->uio_iovcnt == 1 &&
	361	uio->uio_segflg == UIO_USERSPACE &&
	362	uio->uio_resid == uio->uio_iov->iov_len &&
a11aaa81	363	(curthread->td_flags & TDF_DEADLKTREAT) == 0) {
984263bc MD	364	int secsize; /* Media sector size */
	365	off_t filebytes; /* Bytes left of file */
	366	int blockbytes; /* Bytes left of file in full blocks */
	367	int partialbytes; /* Bytes in last partial block */
	368	int skipbytes; /* Bytes not to read in ffs_rawread */
	369	struct inode *ip;
	370	int error;
	371
	372
	373	/* Only handle sector aligned reads */
	374	ip = VTOI(vp);
	375	secsize = ip->i_devvp->v_rdev->si_bsize_phys;
	376	if ((uio->uio_offset & (secsize - 1)) == 0 &&
	377	(uio->uio_resid & (secsize - 1)) == 0) {
	378
	379	/* Sync dirty pages and buffers if needed */
a11aaa81	380	error = ffs_rawread_sync(vp);
984263bc MD	381	if (error != 0)
	382	return error;
	383
	384	/* Check for end of file */
	385	if (ip->i_size > uio->uio_offset) {
	386	filebytes = ip->i_size - uio->uio_offset;
	387
	388	/* No special eof handling needed ? */
	389	if (uio->uio_resid <= filebytes) {
	390	*workdone = 1;
	391	return ffs_rawread_main(vp, uio);
	392	}
	393
	394	partialbytes = ((unsigned int) ip->i_size) %
	395	ip->i_fs->fs_bsize;
	396	blockbytes = (int) filebytes - partialbytes;
	397	if (blockbytes > 0) {
	398	skipbytes = uio->uio_resid -
	399	blockbytes;
	400	uio->uio_resid = blockbytes;
	401	error = ffs_rawread_main(vp, uio);
	402	uio->uio_resid += skipbytes;
	403	if (error != 0)
	404	return error;
	405	/* Read remaining part using buffer */
	406	}
	407	}
	408	}
	409	}
	410	*workdone = 0;
	411	return 0;
	412	}
	413