Re: kern/54598: mount ntfs panic

["J. Hannken-Illjes" <hannken%eis.cs.tu-bs.de@localhost>]

The following reply was made to PR kern/54598; it has been noted by GNATS.

From: "J. Hannken-Illjes" <hannken%eis.cs.tu-bs.de@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: kern/54598: mount ntfs panic
Date: Tue, 8 Oct 2019 17:27:45 +0200

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 > On 8. Oct 2019, at 16:35, Patrick Welche <prlw1%cam.ac.uk@localhost> wrote:
 <snip>
 > 
 > It appears to already be the first one. (no panics though)
 
 Part of ntfs_subr.c Rev. 1.52 looks suspect.  Please try
 after the first commit with the attached diff reversed.
 
 --
 J. Hannken-Illjes - hannken%eis.cs.tu-bs.de@localhost - TU Braunschweig
 
 
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 --- ntfs_subr.c	28 Jun 2013 17:13:34 -0000	1.51
 +++ ntfs_subr.c	13 Nov 2014 16:49:56 -0000	1.52
 @@ -275,5 +275,4 @@ ntfs_loadntnode(
  {
  	struct filerec  *mfrp;
 -	daddr_t         bn;
  	int		error,off;
  	struct attr    *ap;
 @@ -287,12 +286,19 @@ ntfs_loadntnode(
  	if (ip->i_number < NTFS_SYSNODESNUM) {
  		struct buf     *bp;
 +		daddr_t         bn;
 +		off_t           boff;
  
  		dprintf(("%s: read system node\n", __func__));
  
 -		bn = ntfs_cntobn(ntmp->ntm_mftcn) +
 -			ntmp->ntm_bpmftrec * ip->i_number;
 +		/*
 +		 * Make sure we always read full cluster to
 +		 * prevent buffer cache inconsistency.
 +		 */
 +		boff = ntfs_cntob(ntmp->ntm_mftcn) +
 +		    ntfs_bntob(ntmp->ntm_bpmftrec) * ip->i_number;
 +		bn = ntfs_cntobn(ntfs_btocn(boff));
 +		off = ntfs_btocnoff(boff);
  
 -		error = bread(ntmp->ntm_devvp,
 -			      bn, ntfs_bntob(ntmp->ntm_bpmftrec),
 +		error = bread(ntmp->ntm_devvp, bn, ntfs_cntob(1),
  			      NOCRED, 0, &bp);
  		if (error) {
 @@ -300,5 +306,6 @@ ntfs_loadntnode(
  			goto out;
  		}
 -		memcpy(mfrp, bp->b_data, ntfs_bntob(ntmp->ntm_bpmftrec));
 +		memcpy(mfrp, (char *)bp->b_data + off,
 +		    ntfs_bntob(ntmp->ntm_bpmftrec));
  		bqrelse(bp);
  	} else {
 
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