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Replace flag based union node locking with generic vnode lock, support 

shared and nowait locks and protect un_uppervp and un_*sz with mutex.

Mark file system MPSAFE.
This commit is contained in:
hannken 2011-11-21 18:29:22 +00:00
parent dd89f66f56
commit 4e825063cf
4 changed files with 177 additions and 230 deletions
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47
sys/fs/union/union.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: union.h,v 1.21 2011/08/23 07:39:37 hannken Exp $ */
/* $NetBSD: union.h,v 1.22 2011/11/21 18:29:22 hannken Exp $ */
/*
* Copyright (c) 1994 The Regents of the University of California.
@ -105,28 +105,36 @@ struct union_mount {
#define UN_FILEMODE (S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH)
/*
* A cache of vnode references
* A cache of vnode references.
* Lock requirements are:
*
* : stable
* c unheadlock[hash]
* l un_lock
* m un_lock or vnode lock to read, un_lock and
* exclusive vnode lock to write
* v vnode lock to read, exclusive vnode lock to write
*
* Lock order is vnode then un_lock.
*/
struct union_node {
LIST_ENTRY(union_node) un_cache; /* Hash chain */
struct vnode *un_vnode; /* Back pointer */
struct vnode *un_uppervp; /* overlaying object */
struct vnode *un_lowervp; /* underlying object */
struct vnode *un_dirvp; /* Parent dir of uppervp */
struct vnode *un_pvp; /* Parent vnode */
char *un_path; /* saved component name */
int un_hash; /* saved un_path hash value */
int un_openl; /* # of opens on lowervp */
unsigned int un_flags;
struct vnode **un_dircache; /* cached union stack */
off_t un_uppersz; /* size of upper object */
off_t un_lowersz; /* size of lower object */
lwp_t *un_lwp; /* DIAGNOSTIC only */
kmutex_t un_lock;
LIST_ENTRY(union_node) un_cache; /* c: Hash chain */
struct vnode *un_vnode; /* :: Back pointer */
struct vnode *un_uppervp; /* m: overlaying object */
struct vnode *un_lowervp; /* v: underlying object */
struct vnode *un_dirvp; /* v: Parent dir of uppervp */
struct vnode *un_pvp; /* v: Parent vnode */
char *un_path; /* v: saved component name */
int un_hash; /* v: saved un_path hash */
int un_openl; /* v: # of opens on lowervp */
unsigned int un_flags; /* v: node flags */
unsigned int un_cflags; /* c: cache flags */
struct vnode **un_dircache; /* v: cached union stack */
off_t un_uppersz; /* l: size of upper object */
off_t un_lowersz; /* l: size of lower object */
};
#define UN_WANTED 0x01
#define UN_LOCKED 0x02
#define UN_ULOCK 0x04 /* Upper node is locked */
#define UN_KLOCK 0x08 /* Keep upper node locked on vput */
#define UN_CACHED 0x10 /* In union cache */
@ -162,6 +170,7 @@ int union_readdirhook(struct vnode **, struct file *, struct lwp *);
#define LOWERVP(vp) (VTOUNION(vp)->un_lowervp)
#define UPPERVP(vp) (VTOUNION(vp)->un_uppervp)
#define OTHERVP(vp) (UPPERVP(vp) ? UPPERVP(vp) : LOWERVP(vp))
#define LOCKVP(vp) (UPPERVP(vp) ? UPPERVP(vp) : (vp))
extern int (**union_vnodeop_p)(void *);

141
sys/fs/union/union_subr.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: union_subr.c,v 1.52 2011/11/14 18:38:13 hannken Exp $ */
/* $NetBSD: union_subr.c,v 1.53 2011/11/21 18:29:22 hannken Exp $ */
/*
* Copyright (c) 1994
@ -72,7 +72,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: union_subr.c,v 1.52 2011/11/14 18:38:13 hannken Exp $");
__KERNEL_RCSID(0, "$NetBSD: union_subr.c,v 1.53 2011/11/21 18:29:22 hannken Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@ -93,6 +93,7 @@ __KERNEL_RCSID(0, "$NetBSD: union_subr.c,v 1.52 2011/11/14 18:38:13 hannken Exp
#include <uvm/uvm_extern.h>
#include <fs/union/union.h>
#include <miscfs/genfs/genfs.h>
#include <miscfs/specfs/specdev.h>
/* must be power of two, otherwise change UNION_HASH() */
@ -145,7 +146,9 @@ union_updatevp(struct union_node *un, struct vnode *uppervp,
int nhash = UNION_HASH(uppervp, lowervp);
int docache = (lowervp != NULLVP || uppervp != NULLVP);
int lhash, uhash;
bool un_unlock;
KASSERT(VOP_ISLOCKED(UNIONTOV(un)) == LK_EXCLUSIVE);
/*
* Ensure locking is ordered from lower to higher
* to avoid deadlocks.
@ -164,8 +167,8 @@ union_updatevp(struct union_node *un, struct vnode *uppervp,
mutex_enter(&unheadlock[uhash]);
if (ohash != nhash || !docache) {
if (un->un_flags & UN_CACHED) {
un->un_flags &= ~UN_CACHED;
if (un->un_cflags & UN_CACHED) {
un->un_cflags &= ~UN_CACHED;
LIST_REMOVE(un, un_cache);
}
}
@ -186,15 +189,30 @@ union_updatevp(struct union_node *un, struct vnode *uppervp,
}
}
un->un_lowervp = lowervp;
mutex_enter(&un->un_lock);
un->un_lowersz = VNOVAL;
mutex_exit(&un->un_lock);
}
if (un->un_uppervp != uppervp) {
if (un->un_uppervp)
if (un->un_uppervp) {
un_unlock = false;
vrele(un->un_uppervp);
} else
un_unlock = true;
mutex_enter(&un->un_lock);
un->un_uppervp = uppervp;
mutex_exit(&un->un_lock);
if (un_unlock) {
struct vop_unlock_args ap;
ap.a_vp = UNIONTOV(un);
genfs_unlock(&ap);
}
mutex_enter(&un->un_lock);
un->un_uppersz = VNOVAL;
mutex_exit(&un->un_lock);
/* Update union vnode interlock. */
if (uppervp != NULL) {
mutex_obj_hold(uppervp->v_interlock);
@ -205,7 +223,7 @@ union_updatevp(struct union_node *un, struct vnode *uppervp,
if (docache && (ohash != nhash)) {
LIST_INSERT_HEAD(&unhead[nhash], un, un_cache);
un->un_flags |= UN_CACHED;
un->un_cflags |= UN_CACHED;
}
mutex_exit(&unheadlock[nhash]);
@ -229,20 +247,23 @@ union_newupper(struct union_node *un, struct vnode *uppervp)
* Keep track of size changes in the underlying vnodes.
* If the size changes, then callback to the vm layer
* giving priority to the upper layer size.
*
* Mutex un_lock hold on entry and released on return.
*/
void
union_newsize(struct vnode *vp, off_t uppersz, off_t lowersz)
{
struct union_node *un;
struct union_node *un = VTOUNION(vp);
off_t sz;
KASSERT(mutex_owned(&un->un_lock));
/* only interested in regular files */
if (vp->v_type != VREG) {
mutex_exit(&un->un_lock);
uvm_vnp_setsize(vp, 0);
return;
}
un = VTOUNION(vp);
sz = VNOVAL;
if ((uppersz != VNOVAL) && (un->un_uppersz != uppersz)) {
@ -256,6 +277,7 @@ union_newsize(struct vnode *vp, off_t uppersz, off_t lowersz)
if (sz == VNOVAL)
sz = un->un_lowersz;
}
mutex_exit(&un->un_lock);
if (sz != VNOVAL) {
#ifdef UNION_DIAGNOSTIC
@ -319,6 +341,9 @@ union_allocvp(
int vflag, iflag;
int try;
if (uppervp)
KASSERT(VOP_ISLOCKED(uppervp) == LK_EXCLUSIVE);
if (uppervp == NULLVP && lowervp == NULLVP)
panic("union: unidentifiable allocation");
@ -374,61 +399,33 @@ loop:
(un->un_uppervp == uppervp ||
un->un_uppervp == NULLVP) &&
(UNIONTOV(un)->v_mount == mp)) {
int lflag;
if (uppervp != NULL && (uppervp == dvp ||
uppervp == un->un_uppervp))
/* "." or already locked. */
lflag = 0;
else
lflag = LK_EXCLUSIVE;
vp = UNIONTOV(un);
mutex_enter(vp->v_interlock);
if (vget(vp, 0)) {
mutex_exit(&unheadlock[hash]);
mutex_exit(&unheadlock[hash]);
if (vget(vp, lflag))
goto loop;
}
break;
}
}
mutex_exit(&unheadlock[hash]);
if (un)
break;
mutex_exit(&unheadlock[hash]);
}
if (un) {
/*
* Obtain a lock on the union_node.
* uppervp is locked, though un->un_uppervp
* may not be. this doesn't break the locking
* hierarchy since in the case that un->un_uppervp
* is not yet locked it will be vrele'd and replaced
* with uppervp.
*/
if ((dvp != NULLVP) && (uppervp == dvp)) {
/*
* Access ``.'', so (un) will already
* be locked. Since this process has
* the lock on (uppervp) no other
* process can hold the lock on (un).
*/
KASSERT((un->un_flags & UN_LOCKED) != 0);
KASSERT(curlwp == NULL || un->un_lwp == NULL ||
un->un_lwp == curlwp);
} else {
if (un->un_flags & UN_LOCKED) {
vrele(UNIONTOV(un));
un->un_flags |= UN_WANTED;
(void) tsleep(&un->un_flags, PINOD,
"unionalloc", 0);
goto loop;
}
un->un_flags |= UN_LOCKED;
un->un_lwp = curlwp;
}
/*
* At this point, the union_node is locked,
* un->un_uppervp may not be locked, and uppervp
* is locked or nil.
*/
KASSERT(VOP_ISLOCKED(UNIONTOV(un)) == LK_EXCLUSIVE);
KASSERT(uppervp == NULL ||
VOP_ISLOCKED(uppervp) == LK_EXCLUSIVE);
/*
* Save information about the upper layer.
*/
@ -438,10 +435,8 @@ loop:
vrele(uppervp);
}
if (un->un_uppervp) {
un->un_flags |= UN_ULOCK;
if (un->un_uppervp)
un->un_flags &= ~UN_KLOCK;
}
/*
* Save information about the lower layer.
@ -536,6 +531,7 @@ loop:
spec_node_init(*vpp, rdev);
un = VTOUNION(*vpp);
mutex_init(&un->un_lock, MUTEX_DEFAULT, IPL_NONE);
un->un_vnode = *vpp;
un->un_uppervp = uppervp;
un->un_lowervp = lowervp;
@ -544,15 +540,23 @@ loop:
vref(undvp);
un->un_dircache = 0;
un->un_openl = 0;
un->un_flags = UN_LOCKED;
un->un_flags = 0;
un->un_cflags = 0;
if (uppervp == NULL) {
struct vop_lock_args ap;
ap.a_vp = UNIONTOV(un);
ap.a_flags = LK_EXCLUSIVE;
error = genfs_lock(&ap);
KASSERT(error == 0);
}
mutex_enter(&un->un_lock);
un->un_uppersz = VNOVAL;
un->un_lowersz = VNOVAL;
union_newsize(*vpp, uppersz, lowersz);
if (un->un_uppervp)
un->un_flags |= UN_ULOCK;
un->un_lwp = curlwp;
if (dvp && cnp && (lowervp != NULLVP)) {
un->un_hash = cnp->cn_hash;
un->un_path = malloc(cnp->cn_namelen+1, M_TEMP, M_WAITOK);
@ -568,7 +572,7 @@ loop:
if (docache) {
LIST_INSERT_HEAD(&unhead[hash], un, un_cache);
un->un_flags |= UN_CACHED;
un->un_cflags |= UN_CACHED;
}
if (xlowervp)
@ -590,8 +594,8 @@ union_freevp(struct vnode *vp)
hash = UNION_HASH(un->un_uppervp, un->un_lowervp);
mutex_enter(&unheadlock[hash]);
if (un->un_flags & UN_CACHED) {
un->un_flags &= ~UN_CACHED;
if (un->un_cflags & UN_CACHED) {
un->un_cflags &= ~UN_CACHED;
LIST_REMOVE(un, un_cache);
}
mutex_exit(&unheadlock[hash]);
@ -606,6 +610,7 @@ union_freevp(struct vnode *vp)
vrele(un->un_dirvp);
if (un->un_path)
free(un->un_path, M_TEMP);
mutex_destroy(&un->un_lock);
free(vp->v_data, M_TEMP);
vp->v_data = NULL;
@ -691,9 +696,8 @@ union_copyup(struct union_node *un, int docopy, kauth_cred_t cred,
if (error)
return (error);
/* at this point, uppervp is locked */
KASSERT(VOP_ISLOCKED(uvp) == LK_EXCLUSIVE);
union_newupper(un, uvp);
un->un_flags |= UN_ULOCK;
lvp = un->un_lowervp;
@ -954,9 +958,10 @@ union_vn_close(struct vnode *vp, int fmode, kauth_cred_t cred, struct lwp *l)
void
union_removed_upper(struct union_node *un)
{
struct vnode *vp = UNIONTOV(un);
int hash;
KASSERT((un->un_flags & UN_ULOCK) == 0);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
#if 1
/*
* We do not set the uppervp to NULLVP here, because lowervp
@ -973,10 +978,11 @@ union_removed_upper(struct union_node *un)
#endif
hash = UNION_HASH(un->un_uppervp, un->un_lowervp);
VOP_UNLOCK(vp);
mutex_enter(&unheadlock[hash]);
if (un->un_flags & UN_CACHED) {
un->un_flags &= ~UN_CACHED;
if (un->un_cflags & UN_CACHED) {
un->un_cflags &= ~UN_CACHED;
LIST_REMOVE(un, un_cache);
}
mutex_exit(&unheadlock[hash]);
@ -1097,6 +1103,7 @@ union_diruncache(struct union_node *un)
{
struct vnode **vpp;
KASSERT(VOP_ISLOCKED(UNIONTOV(un)) == LK_EXCLUSIVE);
if (un->un_dircache != 0) {
for (vpp = un->un_dircache; *vpp != NULLVP; vpp++)
vrele(*vpp);
@ -1212,7 +1219,9 @@ union_readdirhook(struct vnode **vpp, struct file *fp, struct lwp *l)
* If the directory is opaque,
* then don't show lower entries
*/
vn_lock(vp, LK_SHARED | LK_RETRY);
error = VOP_GETATTR(vp, &va, fp->f_cred);
VOP_UNLOCK(vp);
if (error || (va.va_flags & OPAQUE))
return error;

6
sys/fs/union/union_vfsops.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: union_vfsops.c,v 1.64 2011/08/28 08:27:57 hannken Exp $ */
/* $NetBSD: union_vfsops.c,v 1.65 2011/11/21 18:29:22 hannken Exp $ */
/*
* Copyright (c) 1994 The Regents of the University of California.
@ -77,7 +77,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: union_vfsops.c,v 1.64 2011/08/28 08:27:57 hannken Exp $");
__KERNEL_RCSID(0, "$NetBSD: union_vfsops.c,v 1.65 2011/11/21 18:29:22 hannken Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@ -208,6 +208,8 @@ union_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
goto bad;
}
mp->mnt_iflag |= IMNT_MPSAFE;
/*
* Unless the mount is readonly, ensure that the top layer
* supports whiteout operations

213
sys/fs/union/union_vnops.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: union_vnops.c,v 1.48 2011/11/14 18:42:57 hannken Exp $ */
/* $NetBSD: union_vnops.c,v 1.49 2011/11/21 18:29:22 hannken Exp $ */
/*
* Copyright (c) 1992, 1993, 1994, 1995
@ -72,7 +72,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: union_vnops.c,v 1.48 2011/11/14 18:42:57 hannken Exp $");
__KERNEL_RCSID(0, "$NetBSD: union_vnops.c,v 1.49 2011/11/21 18:29:22 hannken Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@ -189,8 +189,6 @@ const struct vnodeopv_entry_desc union_vnodeop_entries[] = {
const struct vnodeopv_desc union_vnodeop_opv_desc =
{ &union_vnodeop_p, union_vnodeop_entries };
#define FIXUP(un) \
KASSERT(((un)->un_flags & UN_ULOCK) == UN_ULOCK)
#define NODE_IS_SPECIAL(vp) \
((vp)->v_type == VBLK || (vp)->v_type == VCHR || \
(vp)->v_type == VSOCK || (vp)->v_type == VFIFO)
@ -309,41 +307,8 @@ start:
* on and just return that vnode.
*/
if (upperdvp != NULLVP) {
FIXUP(dun);
/*
* If we're doing `..' in the underlying filesystem,
* we must drop our lock on the union node before
* going up the tree in the lower file system--if we block
* on the lowervp lock, and that's held by someone else
* coming down the tree and who's waiting for our lock,
* we would be hosed.
*/
if (cnp->cn_flags & ISDOTDOT) {
/* retain lock on underlying VP */
dun->un_flags |= UN_KLOCK;
VOP_UNLOCK(dvp);
}
uerror = union_lookup1(um->um_uppervp, &upperdvp,
&uppervp, cnp);
if (cnp->cn_flags & ISDOTDOT) {
if (dun->un_uppervp == upperdvp) {
/*
* we got the underlying bugger back locked...
* now take back the union node lock. Since we
* hold the uppervp lock, we can diddle union
* locking flags at will. :)
*/
dun->un_flags |= UN_ULOCK;
}
/*
* if upperdvp got swapped out, it means we did
* some mount point magic, and we do not have
* dun->un_uppervp locked currently--so we get it
* locked here (don't set the UN_ULOCK flag).
*/
vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
}
if (cnp->cn_consume != 0) {
*ap->a_vpp = uppervp;
return (uerror);
@ -480,12 +445,10 @@ start:
* to get the componentname right.
*/
if (upperdvp) {
dun->un_flags &= ~UN_ULOCK;
VOP_UNLOCK(upperdvp);
uerror = union_mkshadow(um, upperdvp, cnp,
&uppervp);
vn_lock(upperdvp, LK_EXCLUSIVE | LK_RETRY);
dun->un_flags |= UN_ULOCK;
if (uerror == 0 && cnp->cn_nameiop != LOOKUP) {
vput(uppervp);
if (lowervp != NULLVP)
@ -537,8 +500,6 @@ union_create(void *v)
struct vnode *vp;
struct mount *mp;
FIXUP(un);
vref(dvp);
un->un_flags |= UN_KLOCK;
mp = ap->a_dvp->v_mount;
@ -572,7 +533,6 @@ union_whiteout(void *v)
if (un->un_uppervp == NULLVP)
return (EOPNOTSUPP);
FIXUP(un);
return (VOP_WHITEOUT(un->un_uppervp, cnp, ap->a_flags));
}
@ -594,8 +554,6 @@ union_mknod(void *v)
struct vnode *vp;
struct mount *mp;
FIXUP(un);
vref(dvp);
un->un_flags |= UN_KLOCK;
mp = ap->a_dvp->v_mount;
@ -669,8 +627,6 @@ union_open(void *v)
(ap->a_vp->v_mount->mnt_flag & MNT_NODEV))
return ENXIO;
FIXUP(un);
error = VOP_OPEN(tvp, mode, cred);
return (error);
@ -758,7 +714,6 @@ union_access(void *v)
if ((vp = un->un_uppervp) != NULLVP) {
FIXUP(un);
ap->a_vp = vp;
return (VCALL(vp, VOFFSET(vop_access), ap));
}
@ -818,12 +773,10 @@ union_getattr(void *v)
vp = un->un_uppervp;
if (vp != NULLVP) {
if (un->un_flags & UN_LOCKED)
FIXUP(un);
error = VOP_GETATTR(vp, vap, ap->a_cred);
if (error)
return (error);
mutex_enter(&un->un_lock);
union_newsize(ap->a_vp, vap->va_size, VNOVAL);
}
@ -845,6 +798,7 @@ union_getattr(void *v)
VOP_UNLOCK(vp);
if (error)
return (error);
mutex_enter(&un->un_lock);
union_newsize(ap->a_vp, VNOVAL, vap->va_size);
}
@ -929,10 +883,11 @@ union_setattr(void *v)
* otherwise.
*/
if (un->un_uppervp != NULLVP) {
FIXUP(un);
error = VOP_SETATTR(un->un_uppervp, vap, ap->a_cred);
if ((error == 0) && (vap->va_size != VNOVAL))
if ((error == 0) && (vap->va_size != VNOVAL)) {
mutex_enter(&un->un_lock);
union_newsize(ap->a_vp, vap->va_size, VNOVAL);
}
} else {
KASSERT(un->un_lowervp != NULLVP);
if (NODE_IS_SPECIAL(un->un_lowervp)) {
@ -964,8 +919,6 @@ union_read(void *v)
if (dolock)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
else
FIXUP(VTOUNION(ap->a_vp));
error = VOP_READ(vp, ap->a_uio, ap->a_ioflag, ap->a_cred);
if (dolock)
VOP_UNLOCK(vp);
@ -979,14 +932,21 @@ union_read(void *v)
if (error == 0) {
struct union_node *un = VTOUNION(ap->a_vp);
off_t cur = ap->a_uio->uio_offset;
off_t usz = VNOVAL, lsz = VNOVAL;
mutex_enter(&un->un_lock);
if (vp == un->un_uppervp) {
if (cur > un->un_uppersz)
union_newsize(ap->a_vp, cur, VNOVAL);
usz = cur;
} else {
if (cur > un->un_lowersz)
union_newsize(ap->a_vp, VNOVAL, cur);
lsz = cur;
}
if (usz != VNOVAL || lsz != VNOVAL)
union_newsize(ap->a_vp, usz, lsz);
else
mutex_exit(&un->un_lock);
}
return (error);
@ -1018,7 +978,6 @@ union_write(void *v)
panic("union: missing upper layer in write");
}
FIXUP(un);
error = VOP_WRITE(vp, ap->a_uio, ap->a_ioflag, ap->a_cred);
/*
@ -1028,8 +987,11 @@ union_write(void *v)
if (error == 0) {
off_t cur = ap->a_uio->uio_offset;
mutex_enter(&un->un_lock);
if (cur > un->un_uppersz)
union_newsize(ap->a_vp, cur, VNOVAL);
else
mutex_exit(&un->un_lock);
}
return (error);
@ -1131,8 +1093,6 @@ union_fsync(void *v)
if (dolock)
vn_lock(targetvp, LK_EXCLUSIVE | LK_RETRY);
else
FIXUP(VTOUNION(ap->a_vp));
error = VOP_FSYNC(targetvp, ap->a_cred, ap->a_flags,
ap->a_offlo, ap->a_offhi);
if (dolock)
@ -1177,11 +1137,9 @@ union_remove(void *v)
struct vnode *dvp = dun->un_uppervp;
struct vnode *vp = un->un_uppervp;
FIXUP(dun);
vref(dvp);
dun->un_flags |= UN_KLOCK;
vput(ap->a_dvp);
FIXUP(un);
vref(vp);
un->un_flags |= UN_KLOCK;
vput(ap->a_vp);
@ -1192,7 +1150,6 @@ union_remove(void *v)
if (!error)
union_removed_upper(un);
} else {
FIXUP(dun);
error = union_mkwhiteout(
MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount),
dun->un_uppervp, ap->a_cnp, un);
@ -1226,19 +1183,18 @@ union_link(void *v)
} else {
struct union_node *un = VTOUNION(ap->a_vp);
if (un->un_uppervp == NULLVP) {
const bool droplock = (dun->un_uppervp == un->un_dirvp);
/*
* Needs to be copied before we can link it.
*/
vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
if (dun->un_uppervp == un->un_dirvp) {
dun->un_flags &= ~UN_ULOCK;
if (droplock)
VOP_UNLOCK(dun->un_uppervp);
}
error = union_copyup(un, 1, cnp->cn_cred, curlwp);
if (dun->un_uppervp == un->un_dirvp) {
if (droplock) {
vn_lock(dun->un_uppervp,
LK_EXCLUSIVE | LK_RETRY);
dun->un_flags |= UN_ULOCK;
/*
* During copyup, we dropped the lock on the
* dir and invalidated any saved namei lookup
@ -1283,7 +1239,6 @@ union_link(void *v)
return (error);
}
FIXUP(dun);
vref(dvp);
dun->un_flags |= UN_KLOCK;
vput(ap->a_dvp);
@ -1408,7 +1363,6 @@ union_mkdir(void *v)
int error;
struct vnode *vp;
FIXUP(un);
vref(dvp);
un->un_flags |= UN_KLOCK;
VOP_UNLOCK(ap->a_dvp);
@ -1457,11 +1411,9 @@ union_rmdir(void *v)
struct vnode *dvp = dun->un_uppervp;
struct vnode *vp = un->un_uppervp;
FIXUP(dun);
vref(dvp);
dun->un_flags |= UN_KLOCK;
vput(ap->a_dvp);
FIXUP(un);
vref(vp);
un->un_flags |= UN_KLOCK;
vput(ap->a_vp);
@ -1472,7 +1424,6 @@ union_rmdir(void *v)
if (!error)
union_removed_upper(un);
} else {
FIXUP(dun);
error = union_mkwhiteout(
MOUNTTOUNIONMOUNT(UNIONTOV(dun)->v_mount),
dun->un_uppervp, ap->a_cnp, un);
@ -1500,7 +1451,6 @@ union_symlink(void *v)
if (dvp != NULLVP) {
int error;
FIXUP(un);
vref(dvp);
un->un_flags |= UN_KLOCK;
vput(ap->a_dvp);
@ -1538,7 +1488,6 @@ union_readdir(void *v)
if (uvp == NULLVP)
return (0);
FIXUP(un);
ap->a_vp = uvp;
return (VCALL(uvp, VOFFSET(vop_readdir), ap));
}
@ -1557,8 +1506,6 @@ union_readlink(void *v)
if (dolock)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
else
FIXUP(VTOUNION(ap->a_vp));
ap->a_vp = vp;
error = VCALL(vp, VOFFSET(vop_readlink), ap);
if (dolock)
@ -1613,7 +1560,7 @@ union_inactive(void *v)
un->un_dircache = 0;
}
*ap->a_recycle = ((un->un_flags & UN_CACHED) == 0);
*ap->a_recycle = ((un->un_cflags & UN_CACHED) == 0);
VOP_UNLOCK(vp);
return (0);
@ -1638,54 +1585,33 @@ union_lock(void *v)
struct vnode *a_vp;
int a_flags;
} */ *ap = v;
struct vnode *vp = ap->a_vp;
int flags = ap->a_flags;
struct vnode *vp;
struct union_node *un;
int error;
/* XXX unionfs can't handle shared locks yet */
if ((flags & LK_SHARED) != 0) {
flags = (flags & ~LK_SHARED) | LK_EXCLUSIVE;
un = VTOUNION(ap->a_vp);
mutex_enter(&un->un_lock);
for (;;) {
vp = LOCKVP(ap->a_vp);
mutex_exit(&un->un_lock);
if (vp == ap->a_vp)
error = genfs_lock(ap);
else
error = VOP_LOCK(vp, ap->a_flags);
if (error != 0)
return error;
mutex_enter(&un->un_lock);
if (vp == LOCKVP(ap->a_vp))
break;
if (vp == ap->a_vp)
genfs_unlock(ap);
else
VOP_UNLOCK(vp);
}
KASSERT((un->un_flags & UN_KLOCK) == 0);
mutex_exit(&un->un_lock);
start:
un = VTOUNION(vp);
if (un->un_uppervp != NULLVP) {
if (((un->un_flags & UN_ULOCK) == 0) &&
(vp->v_usecount != 0)) {
/*
* We MUST always use the order of: take upper
* vp lock, manipulate union node flags, drop
* upper vp lock. This code must not be an
* exception.
*/
error = vn_lock(un->un_uppervp, flags);
if (error)
return (error);
un->un_flags |= UN_ULOCK;
}
#ifdef DIAGNOSTIC
if (un->un_flags & UN_KLOCK) {
vprint("union: dangling klock", vp);
panic("union: dangling upper lock (%p)", vp);
}
#endif
}
/* XXX ignores LK_NOWAIT */
if (un->un_flags & UN_LOCKED) {
KASSERT(curlwp == NULL || un->un_lwp == NULL ||
un->un_lwp != curlwp);
un->un_flags |= UN_WANTED;
tsleep(&un->un_flags, PINOD, "unionlk2", 0);
goto start;
}
un->un_lwp = curlwp;
un->un_flags |= UN_LOCKED;
return (0);
return error;
}
/*
@ -1706,27 +1632,22 @@ union_unlock(void *v)
struct vnode *a_vp;
int a_flags;
} */ *ap = v;
struct union_node *un = VTOUNION(ap->a_vp);
struct vnode *vp;
struct union_node *un;
KASSERT((un->un_flags & UN_LOCKED) != 0);
KASSERT(curlwp == NULL || un->un_lwp == NULL ||
un->un_lwp == curlwp);
un->un_flags &= ~UN_LOCKED;
if ((un->un_flags & (UN_ULOCK|UN_KLOCK)) == UN_ULOCK)
VOP_UNLOCK(un->un_uppervp);
un->un_flags &= ~(UN_ULOCK|UN_KLOCK);
if (un->un_flags & UN_WANTED) {
un->un_flags &= ~UN_WANTED;
wakeup( &un->un_flags);
un = VTOUNION(ap->a_vp);
vp = LOCKVP(ap->a_vp);
if ((un->un_flags & UN_KLOCK) == UN_KLOCK) {
KASSERT(vp != ap->a_vp);
un->un_flags &= ~UN_KLOCK;
return 0;
}
if (vp == ap->a_vp)
genfs_unlock(ap);
else
VOP_UNLOCK(vp);
un->un_lwp = NULL;
return (0);
return 0;
}
int
@ -1745,8 +1666,6 @@ union_bmap(void *v)
if (dolock)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
else
FIXUP(VTOUNION(ap->a_vp));
ap->a_vp = vp;
error = VCALL(vp, VOFFSET(vop_bmap), ap);
if (dolock)
@ -1784,8 +1703,18 @@ union_islocked(void *v)
struct vop_islocked_args /* {
struct vnode *a_vp;
} */ *ap = v;
struct vnode *vp;
struct union_node *un;
return ((VTOUNION(ap->a_vp)->un_flags & UN_LOCKED) ? LK_EXCLUSIVE : 0);
un = VTOUNION(ap->a_vp);
mutex_enter(&un->un_lock);
vp = LOCKVP(ap->a_vp);
mutex_exit(&un->un_lock);
if (vp == ap->a_vp)
return genfs_islocked(ap);
else
return VOP_ISLOCKED(vp);
}
int
@ -1802,8 +1731,6 @@ union_pathconf(void *v)
if (dolock)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
else
FIXUP(VTOUNION(ap->a_vp));
ap->a_vp = vp;
error = VCALL(vp, VOFFSET(vop_pathconf), ap);
if (dolock)