Continue the objectification of the swapdev backends:
Remove the vnode and dev_t fields and replace them with a void *. Introduce separate strategy functions for devices and regular (NFS) vnodes. For devices we don't need the vnode v_numoutput stuff. Add a generic swaponsomething() function to add a swapdevice and split the remainder of swaponvp() into swaponvp() and swapondev() which calls this backend.
This commit is contained in:
Poul-Henning Kamp
parent
4b03903a46
commit
59efee01a3
@ -148,11 +148,10 @@ typedef void sw_strategy_t(struct buf *bp, struct swdevt *sw);
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* Swap device table
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*/
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struct swdevt {
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dev_t sw_dev;
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int sw_flags;
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int sw_nblks;
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int sw_used;
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struct vnode *sw_vp;
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void *sw_id;
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swblk_t sw_first;
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swblk_t sw_end;
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struct blist *sw_blist;
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@ -257,7 +256,8 @@ SYSCTL_INT(_vm, OID_AUTO, dmmax,
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static void swp_sizecheck(void);
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static void swp_pager_sync_iodone(struct buf *bp);
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static void swp_pager_async_iodone(struct buf *bp);
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static int swaponvp(struct thread *, struct vnode *, dev_t , u_long);
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static int swapondev(struct thread *, struct vnode *);
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static int swaponvp(struct thread *, struct vnode *, u_long);
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/*
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* Swap bitmap functions
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@ -2002,18 +2002,14 @@ swp_pager_meta_ctl(vm_object_t object, vm_pindex_t pindex, int flags)
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static void
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swapdev_strategy(struct buf *bp, struct swdevt *sp)
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{
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int s, sz;
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struct vnode *vp;
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int s;
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struct vnode *vp, *vp2;
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sz = howmany(bp->b_bcount, PAGE_SIZE);
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bp->b_dev = sp->sw_dev;
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/*
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* Convert from PAGE_SIZE'd to DEV_BSIZE'd chunks for the actual I/O
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*/
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bp->b_dev = NODEV;
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bp->b_blkno = ctodb(bp->b_blkno - sp->sw_first);
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vhold(sp->sw_vp);
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vp2 = sp->sw_id;
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vhold(vp2);
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s = splvm();
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if (bp->b_iocmd == BIO_WRITE) {
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vp = bp->b_vp;
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@ -2026,16 +2022,26 @@ swapdev_strategy(struct buf *bp, struct swdevt *sp)
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}
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VI_UNLOCK(vp);
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}
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VI_LOCK(sp->sw_vp);
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sp->sw_vp->v_numoutput++;
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VI_UNLOCK(sp->sw_vp);
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VI_LOCK(vp2);
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vp2->v_numoutput++;
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VI_UNLOCK(vp2);
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}
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bp->b_vp = sp->sw_vp;
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bp->b_vp = vp2;
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splx(s);
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if (bp->b_vp->v_type == VCHR)
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VOP_SPECSTRATEGY(bp->b_vp, bp);
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else
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VOP_STRATEGY(bp->b_vp, bp);
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VOP_STRATEGY(vp2, bp);
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return;
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}
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static void
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swapdev_devstrategy(struct buf *bp, struct swdevt *sp)
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{
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struct vnode *vp;
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vp = sp->sw_id;
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bp->b_dev = vp->v_rdev;
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bp->b_blkno = ctodb(bp->b_blkno - sp->sw_first);
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VOP_SPECSTRATEGY(vp, bp);
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return;
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}
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@ -2089,7 +2095,7 @@ swapon(struct thread *td, struct swapon_args *uap)
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vp = nd.ni_vp;
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if (vn_isdisk(vp, &error))
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error = swaponvp(td, vp, vp->v_rdev, 0);
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error = swapondev(td, vp);
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else if (vp->v_type == VREG &&
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(vp->v_mount->mnt_vfc->vfc_flags & VFCF_NETWORK) != 0 &&
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(error = VOP_GETATTR(vp, &attr, td->td_ucred, td)) == 0) {
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@ -2097,7 +2103,7 @@ swapon(struct thread *td, struct swapon_args *uap)
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* Allow direct swapping to NFS regular files in the same
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* way that nfs_mountroot() sets up diskless swapping.
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*/
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error = swaponvp(td, vp, NODEV, attr.va_size / DEV_BSIZE);
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error = swaponvp(td, vp, attr.va_size / DEV_BSIZE);
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}
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if (error)
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@ -2110,19 +2116,15 @@ done2:
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return (error);
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}
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static int
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swaponvp(struct thread *td, struct vnode *vp, dev_t dev, u_long nblks)
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static void
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swaponsomething(struct vnode *vp, u_long nblks, sw_strategy_t *strategy)
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{
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struct swdevt *sp;
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swblk_t dvbase;
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int error;
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u_long mblocks;
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off_t mediasize;
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dvbase = 0;
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TAILQ_FOREACH(sp, &swtailq, sw_list) {
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if (sp->sw_vp == vp)
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return (EBUSY);
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if (sp->sw_end >= dvbase) {
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/*
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* We put one uncovered page between the devices
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@ -2133,31 +2135,6 @@ swaponvp(struct thread *td, struct vnode *vp, dev_t dev, u_long nblks)
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}
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}
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(void) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
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#ifdef MAC
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error = mac_check_system_swapon(td->td_ucred, vp);
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if (error == 0)
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#endif
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error = VOP_OPEN(vp, FREAD | FWRITE, td->td_ucred, td, -1);
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(void) VOP_UNLOCK(vp, 0, td);
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if (error)
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return (error);
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if (nblks == 0) {
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error = VOP_IOCTL(vp, DIOCGMEDIASIZE, (caddr_t)&mediasize,
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FREAD, td->td_ucred, td);
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if (error == 0)
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nblks = mediasize / DEV_BSIZE;
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}
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/*
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* XXX: We should also check that the sectorsize makes sense
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* XXX: it should be a power of two, no larger than the page size.
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*/
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if (nblks == 0) {
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(void) VOP_CLOSE(vp, FREAD | FWRITE, td->td_ucred, td);
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return (ENXIO);
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}
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/*
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* If we go beyond this, we get overflows in the radix
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* tree bitmap code.
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@ -2178,14 +2155,13 @@ swaponvp(struct thread *td, struct vnode *vp, dev_t dev, u_long nblks)
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nblks = dbtoc(nblks);
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sp = malloc(sizeof *sp, M_VMPGDATA, M_WAITOK | M_ZERO);
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sp->sw_vp = vp;
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sp->sw_dev = dev;
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sp->sw_id = vp;
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sp->sw_flags = 0;
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sp->sw_nblks = nblks;
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sp->sw_used = 0;
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sp->sw_first = dvbase;
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sp->sw_end = dvbase + nblks;
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sp->sw_strategy = swapdev_strategy;
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sp->sw_strategy = strategy;
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sp->sw_blist = blist_create(nblks);
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/*
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@ -2198,7 +2174,73 @@ swaponvp(struct thread *td, struct vnode *vp, dev_t dev, u_long nblks)
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nswapdev++;
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swap_pager_avail += nblks;
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swap_pager_full = 0;
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}
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static int
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swapondev(struct thread *td, struct vnode *vp)
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{
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struct swdevt *sp;
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int error;
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off_t mediasize;
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u_long nblks;
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TAILQ_FOREACH(sp, &swtailq, sw_list)
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if (sp->sw_id == vp)
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return (EBUSY);
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(void) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
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#ifdef MAC
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error = mac_check_system_swapon(td->td_ucred, vp);
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if (error == 0)
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#endif
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error = VOP_OPEN(vp, FREAD | FWRITE, td->td_ucred, td, -1);
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(void) VOP_UNLOCK(vp, 0, td);
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if (error)
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return (error);
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error = VOP_IOCTL(vp, DIOCGMEDIASIZE, (caddr_t)&mediasize,
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FREAD, td->td_ucred, td);
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if (error == 0)
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nblks = mediasize / DEV_BSIZE;
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else {
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(void) VOP_CLOSE(vp, FREAD | FWRITE, td->td_ucred, td);
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return (ENXIO);
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}
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/*
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* XXX: We should also check that the sectorsize makes sense
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* XXX: it should be a power of two, no larger than the page size.
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*/
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swaponsomething(vp, nblks, swapdev_devstrategy);
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return (0);
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}
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static int
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swaponvp(struct thread *td, struct vnode *vp, u_long nblks)
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{
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struct swdevt *sp;
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int error;
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if (nblks == 0)
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return (ENXIO);
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TAILQ_FOREACH(sp, &swtailq, sw_list)
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if (sp->sw_id == vp)
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return (EBUSY);
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(void) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
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#ifdef MAC
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error = mac_check_system_swapon(td->td_ucred, vp);
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if (error == 0)
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#endif
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error = VOP_OPEN(vp, FREAD | FWRITE, td->td_ucred, td, -1);
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(void) VOP_UNLOCK(vp, 0, td);
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if (error)
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return (error);
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swaponsomething(vp, nblks, swapdev_strategy);
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return (0);
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}
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@ -2244,7 +2286,7 @@ swapoff(struct thread *td, struct swapoff_args *uap)
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vp = nd.ni_vp;
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TAILQ_FOREACH(sp, &swtailq, sw_list) {
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if (sp->sw_vp == vp)
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if (sp->sw_id == vp)
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goto found;
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}
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error = EINVAL;
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@ -2291,7 +2333,7 @@ found:
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VOP_CLOSE(vp, FREAD | FWRITE, td->td_ucred, td);
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vrele(vp);
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sp->sw_vp = NULL;
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sp->sw_id = NULL;
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TAILQ_REMOVE(&swtailq, sp, sw_list);
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if (swdevhd == sp)
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swdevhd = NULL;
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@ -2327,6 +2369,7 @@ sysctl_vm_swap_info(SYSCTL_HANDLER_ARGS)
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int error, n;
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struct xswdev xs;
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struct swdevt *sp;
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struct vnode *vp;
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if (arg2 != 1) /* name length */
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return (EINVAL);
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@ -2335,7 +2378,11 @@ sysctl_vm_swap_info(SYSCTL_HANDLER_ARGS)
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TAILQ_FOREACH(sp, &swtailq, sw_list) {
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if (n == *name) {
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xs.xsw_version = XSWDEV_VERSION;
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xs.xsw_dev = dev2udev(sp->sw_dev);
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vp = sp->sw_id;
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if (vp->v_rdev != NULL)
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xs.xsw_dev = dev2udev(vp->v_rdev);
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else
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xs.xsw_dev = NOUDEV;
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xs.xsw_flags = sp->sw_flags;
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xs.xsw_nblks = sp->sw_nblks;
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xs.xsw_used = sp->sw_used;
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