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Fix the situation where an I/O crosses the EOF point. We need to properly

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adjust the bp->b_bcount the same way for unlabeled VN access as dscheck
    does for labeled access.

    We also increase the block size to at least 8K for efficiency.

Reviewed by:	 Tor.Egge@fast.no
This commit is contained in:
Matthew Dillon 1999-09-20 18:06:17 +00:00
parent f7d9e545c0
commit 5b4cc8ee79
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=51469
1 changed files with 29 additions and 4 deletions
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33
sys/dev/vn/vn.c
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@ -98,6 +98,8 @@ static d_strategy_t vnstrategy;
#define CDEV_MAJOR 43
#define BDEV_MAJOR 15
#define VN_BSIZE_BEST 8192
/*
* cdevsw
* D_DISK we want to look like a disk
@ -222,10 +224,16 @@ vnopen(dev_t dev, int flags, int mode, struct proc *p)
* Update si_bsize fields for device. This data will be overriden by
* the slice/parition code for vn accesses through partitions, and
* used directly if you open the 'whole disk' device.
*
* si_bsize_best must be reinitialized in case VN has been
* reconfigured, plus make it at least VN_BSIZE_BEST for efficiency.
*/
dev->si_bsize_phys = vn->sc_secsize;
dev->si_bsize_best = vn->sc_secsize;
if (dev->si_bsize_best < VN_BSIZE_BEST)
dev->si_bsize_best = VN_BSIZE_BEST;
if (flags & FWRITE && vn->sc_flags & VNF_READONLY)
if ((flags & FWRITE) && (vn->sc_flags & VNF_READONLY))
return (EACCES);
IFOPT(vn, VN_FOLLOW)
@ -281,7 +289,6 @@ vnstrategy(struct buf *bp)
struct vn_softc *vn;
int error;
int isvplocked = 0;
long sz;
struct uio auio;
struct iovec aiov;
@ -310,11 +317,16 @@ vnstrategy(struct buf *bp)
}
} else {
int pbn; /* in sc_secsize chunks */
long sz; /* in sc_secsize chunks */
pbn = bp->b_blkno / (vn->sc_secsize / DEV_BSIZE);
sz = howmany(bp->b_bcount, vn->sc_secsize);
if (pbn < 0 || pbn + sz > vn->sc_size) {
/*
* If out of bounds return an error. If at the EOF point,
* simply read or write less.
*/
if (pbn < 0 || pbn >= vn->sc_size) {
if (pbn != vn->sc_size) {
bp->b_error = EINVAL;
bp->b_flags |= B_ERROR | B_INVAL;
@ -322,6 +334,15 @@ vnstrategy(struct buf *bp)
biodone(bp);
return;
}
/*
* If the request crosses EOF, truncate the request.
*/
if (pbn + sz > vn->sc_size) {
bp->b_bcount -= (pbn + sz - vn->sc_size) *
vn->sc_secsize;
bp->b_resid = bp->b_bcount;
}
bp->b_pblkno = pbn;
}
@ -333,6 +354,10 @@ vnstrategy(struct buf *bp)
} else if (vn->sc_vp) {
/*
* VNODE I/O
*
* If an error occurs, we set B_ERROR but we do not set
* B_INVAL because (for a write anyway), the buffer is
* still valid.
*/
aiov.iov_base = bp->b_data;
aiov.iov_len = bp->b_bcount;
@ -360,7 +385,7 @@ vnstrategy(struct buf *bp)
}
bp->b_resid = auio.uio_resid;
if( error ) {
if (error) {
bp->b_error = error;
bp->b_flags |= B_ERROR;
}