kern/65300: [udf] Can't use sendfile(2) to download files in UDF DVD

[Pav Lucistnik]

The following reply was made to PR kern/65300; it has been noted by GNATS.

From: Pav Lucistnik <pav at FreeBSD.org>
To: bug-followup at FreeBSD.org, alex at alexwang.com
Cc:  
Subject: Re: kern/65300: [udf] Can't use sendfile(2) to download files in
	UDF DVD
Date: Tue, 09 Jan 2007 02:44:45 +0100

 Please try this patch, it fixes the issue for me. Tested on 6-STABLE,
 should apply and work in -CURRENT too.
 
 Index: udf_vnops.c
 ===================================================================
 RCS file: /home/ncvs/src/sys/fs/udf/udf_vnops.c,v
 retrieving revision 1.58.2.2
 diff -a -u -r1.58.2.2 udf_vnops.c
 --- udf_vnops.c	30 Dec 2006 15:42:11 -0000	1.58.2.2
 +++ udf_vnops.c	9 Jan 2007 01:22:12 -0000
 @@ -339,38 +339,60 @@
  	}
  }
  
 +#define lblkno(udfmp, loc)	((loc) >> (udfmp)->bshift)
 +#define blkoff(udfmp, loc)	((loc) & (udfmp)->bmask)
 +#define lblktosize(imp, blk)	((blk) << (udfmp)->bshift)
 +
  static int
 -udf_read(struct vop_read_args *a)
 +udf_read(struct vop_read_args *ap)
  {
 -	struct vnode *vp = a->a_vp;
 -	struct uio *uio = a->a_uio;
 +	struct vnode *vp = ap->a_vp;
 +	struct uio *uio = ap->a_uio;
  	struct udf_node *node = VTON(vp);
 +	struct udf_mnt *udfmp;
  	struct buf *bp;
 -	uint8_t *data;
 -	off_t fsize, offset;
 +	daddr_t lbn, rablock;
 +	off_t diff, fsize;
  	int error = 0;
 -	int size;
 +	long size, n, on;
  
 +	if (uio->uio_resid == 0)
 +		return (0);
  	if (uio->uio_offset < 0)
  		return (EINVAL);
 -
  	fsize = le64toh(node->fentry->inf_len);
 -
 -	while (uio->uio_offset < fsize && uio->uio_resid > 0) {
 -		offset = uio->uio_offset;
 -		if (uio->uio_resid + offset <= fsize)
 -			size = uio->uio_resid;
 -		else
 -			size = fsize - offset;
 -		error = udf_readatoffset(node, &size, offset, &bp, &data);
 -		if (error == 0)
 -			error = uiomove(data, size, uio);
 -		if (bp != NULL)
 +	udfmp = node->udfmp;
 +	do {
 +		lbn = lblkno(udfmp, uio->uio_offset);
 +		on = blkoff(udfmp, uio->uio_offset);
 +		n = min((u_int)(udfmp->bsize - on),
 +			uio->uio_resid);
 +		diff = fsize - uio->uio_offset;
 +		if (diff <= 0)
 +			return (0);
 +		if (diff < n)
 +			n = diff;
 +		size = udfmp->bsize;
 +		rablock = lbn + 1;
 +		if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) {
 +			if (lblktosize(udfmp, rablock) < fsize) {
 +				error = cluster_read(vp, fsize, lbn, size, NOCRED,
 +					uio->uio_resid, (ap->a_ioflag >> 16), &bp);
 +			} else {
 +				error = bread(vp, lbn, size, NOCRED, &bp);
 +			}
 +		} else {
 +			error = bread(vp, lbn, size, NOCRED, &bp);
 +		}
 +		n = min(n, size - bp->b_resid);
 +		if (error) {
  			brelse(bp);
 -		if (error)
 -			break;
 -	};
 +			return (error);
 +		}
  
 +		error = uiomove(bp->b_data + on, (int)n, uio);
 +		brelse(bp);
 +	} while (error == 0 && uio->uio_resid > 0 && n != 0);
  	return (error);
  }
  
 @@ -776,23 +798,29 @@
  	struct vnode *vp;
  	struct udf_node *node;
  	int maxsize;
 +	daddr_t sector;
  	struct bufobj *bo;
 +	int multiplier;
  
  	bp = a->a_bp;
  	vp = a->a_vp;
  	node = VTON(vp);
  
 -	/* cd9660 has this test reversed, but it seems more logical this way */
 -	if (bp->b_blkno != bp->b_lblkno) {
 +	if (bp->b_blkno == bp->b_lblkno) {
  		/*
  		 * Files that are embedded in the fentry don't translate well
  		 * to a block number.  Reject.
  		 */
  		if (udf_bmap_internal(node, bp->b_lblkno * node->udfmp->bsize,
 -		    &bp->b_lblkno, &maxsize)) {
 +		    &sector, &maxsize)) {
  			clrbuf(bp);
  			bp->b_blkno = -1;
  		}
 +
 +		/* bmap gives sector numbers, bio works with device blocks */
 +		multiplier = node->udfmp->bsize / DEV_BSIZE;
 +		bp->b_blkno = sector * multiplier;
 +
  	}
  	if ((long)bp->b_blkno == -1) {
  		bufdone(bp);
 
 -- 
 Pav Lucistnik <pav at oook.cz>
               <pav at FreeBSD.org>
 
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