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- Fix several locking problems in unionfs_mount so that it will come

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closer to passing DEBUG_VFS_LOCKS.
This commit is contained in:
Jeff Roberson 2005-04-27 09:07:13 +00:00
parent 189dd72df3
commit 568556d720
1 changed files with 7 additions and 23 deletions
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30
sys/fs/unionfs/union_vfsops.c
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@ -127,37 +127,18 @@ union_mount(mp, td)
* Obtain lower vnode. Vnode is stored in mp->mnt_vnodecovered.
* We need to reference it but not lock it.
*/
lowerrootvp = mp->mnt_vnodecovered;
VREF(lowerrootvp);
#if 0
/*
* Unlock lower node to avoid deadlock.
*/
if (lowerrootvp->v_op == union_vnodeop_p)
VOP_UNLOCK(lowerrootvp, 0, td);
#endif
/*
* Obtain upper vnode by calling namei() on the path. The
* upperrootvp will be turned referenced but not locked.
* upperrootvp will be turned referenced and locked.
*/
NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT, UIO_SYSSPACE, target, td);
NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, UIO_SYSSPACE, target, td);
error = namei(ndp);
#if 0
if (lowerrootvp->v_op == union_vnodeop_p)
vn_lock(lowerrootvp, LK_EXCLUSIVE | LK_RETRY, td);
#endif
if (error)
goto bad;
NDFREE(ndp, NDF_ONLY_PNBUF);
upperrootvp = ndp->ni_vp;
vrele(ndp->ni_dvp);
ndp->ni_dvp = NULL;
UDEBUG(("mount_root UPPERVP %p locked = %d\n", upperrootvp,
VOP_ISLOCKED(upperrootvp, NULL)));
@ -208,6 +189,8 @@ union_mount(mp, td)
break;
case UNMNT_BELOW:
VOP_UNLOCK(upperrootvp, 0, td);
vn_lock(lowerrootvp, LK_RETRY|LK_EXCLUSIVE, td);
um->um_lowervp = upperrootvp;
um->um_uppervp = lowerrootvp;
upperrootvp = NULL;
@ -244,6 +227,7 @@ union_mount(mp, td)
if (error)
goto bad;
}
VOP_UNLOCK(um->um_uppervp, 0, td);
um->um_cred = crhold(td->td_ucred);
FILEDESC_LOCK_FAST(td->td_proc->p_fd);
@ -305,14 +289,14 @@ union_mount(mp, td)
bad:
if (um) {
if (um->um_uppervp)
vrele(um->um_uppervp);
vput(um->um_uppervp);
if (um->um_lowervp)
vrele(um->um_lowervp);
/* XXX other fields */
free(um, M_UNIONFSMNT);
}
if (upperrootvp)
vrele(upperrootvp);
vput(upperrootvp);
if (lowerrootvp)
vrele(lowerrootvp);
return (error);