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- In reassignbuf() don't unlock vp and lock newvp if they are the same.

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Doing so creates a race where the buf is on neither list.
 - Only vfree() in an error case in vclean() if VSHOULDFREE() thinks we
   should.
 - Convert the error case in vclean() to INVARIANTS from DIAGNOSTIC as this
   really should not happen and is fast to check.
This commit is contained in:
Jeff Roberson 2003-09-20 00:21:48 +00:00
parent 9586afbe64
commit 51b575490c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=120271
1 changed files with 11 additions and 6 deletions
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17
sys/kern/vfs_subr.c
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@ -1869,12 +1869,14 @@ reassignbuf(bp, newvp)
register struct buf *bp;
register struct vnode *newvp;
{
struct vnode *vp;
int delay;
if (newvp == NULL) {
printf("reassignbuf: NULL");
return;
}
vp = bp->b_vp;
++reassignbufcalls;
/*
@ -1887,20 +1889,22 @@ reassignbuf(bp, newvp)
/*
* Delete from old vnode list, if on one.
*/
VI_LOCK(bp->b_vp);
VI_LOCK(vp);
if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) {
buf_vlist_remove(bp);
if (bp->b_vp != newvp) {
if (vp != newvp) {
vdropl(bp->b_vp);
bp->b_vp = NULL; /* for clarification */
}
}
VI_UNLOCK(bp->b_vp);
if (vp != newvp) {
VI_UNLOCK(vp);
VI_LOCK(newvp);
}
/*
* If dirty, put on list of dirty buffers; otherwise insert onto list
* of clean buffers.
*/
VI_LOCK(newvp);
if (bp->b_flags & B_DELWRI) {
if ((newvp->v_iflag & VI_ONWORKLST) == 0) {
switch (newvp->v_type) {
@ -2580,13 +2584,14 @@ vclean(vp, flags, td)
VI_LOCK(vp);
v_incr_usecount(vp, -1);
if (vp->v_usecount <= 0) {
#ifdef DIAGNOSTIC
#ifdef INVARIANTS
if (vp->v_usecount < 0 || vp->v_writecount != 0) {
vprint("vclean: bad ref count", vp);
panic("vclean: ref cnt");
}
#endif
vfree(vp);
if (VSHOULDFREE(vp))
vfree(vp);
}
VI_UNLOCK(vp);
}