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In rev. 1.514, iodone on async buffer may happen before code checks the

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vnode v_flag. For cluster buffers this would result in dereferencing NULL
b_vp. To prevent the panic, cache relevant vnode flag before calling
bstrategy.

Reported by:	Peter Holm, kris
Tested by:	Peter Holm
Reviewed by: tegge
Pointy hat to:	kib
This commit is contained in:
Konstantin Belousov 2006-12-20 09:22:31 +00:00
parent 6d3d33dd7a
commit cc570216bb
1 changed files with 9 additions and 2 deletions
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11
sys/kern/vfs_bio.c
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@ -816,6 +816,8 @@ int
bufwrite(struct buf *bp)
{
int oldflags;
struct vnode *vp;
int vp_md;
CTR3(KTR_BUF, "bufwrite(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
if (bp->b_flags & B_INVAL) {
@ -834,6 +836,12 @@ bufwrite(struct buf *bp)
KASSERT(!(bp->b_vflags & BV_BKGRDINPROG),
("FFS background buffer should not get here %p", bp));
vp = bp->b_vp;
if (vp)
vp_md = vp->v_vflag & VV_MD;
else
vp_md = 0;
/* Mark the buffer clean */
bundirty(bp);
@ -871,8 +879,7 @@ bufwrite(struct buf *bp)
* or syncer daemon trying to clean up as that can lead
* to deadlock.
*/
if ((curthread->td_pflags & TDP_NORUNNINGBUF) == 0 &&
(bp->b_vp->v_vflag & VV_MD) == 0)
if ((curthread->td_pflags & TDP_NORUNNINGBUF) == 0 && !vp_md)
waitrunningbufspace();
}