Re: CVS commit: src/sys

[Taylor R Campbell <riastradh%NetBSD.org@localhost>]

   From: hannken%NetBSD.org@localhost
   Date: Thu, 20 Dec 2012 08:03:46 +0000

   --- sys/fs/msdosfs/msdosfs_vnops.c      29 Apr 2012 22:53:59 -0000      1.83
   +++ sys/fs/msdosfs/msdosfs_vnops.c      20 Dec 2012 08:03:42 -0000      1.84
   @@ -527,7 +527,6 @@ msdosfs_read(void *v)
                       NOCRED, 0, &bp);
                   n = MIN(n, pmp->pm_bpcluster - bp->b_resid);
                   if (error) {
   -                       brelse(bp, 0);

Looks like you need to move the initialization of n to after the error
branch.

   --- sys/ufs/ext2fs/ext2fs_vfsops.c      21 Nov 2012 23:11:23 -0000      1.167
   +++ sys/ufs/ext2fs/ext2fs_vfsops.c      20 Dec 2012 08:03:44 -0000      1.168
   @@ -772,8 +770,8 @@ ext2fs_mountfs(struct vnode *devvp, stru
           return (0);

    out:
   -       KASSERT(bp != NULL);
   -       brelse(bp, 0);
   +       if (bp != NULL)
   +               brelse(bp, 0);


Are bread &c. supposed to guarantee that bp is null on error, or are
they supposed to leave it in an undefined state?  Either way, it seems
to me that the intent ought to be documented in buffercache(9).