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Diffstat (limited to 'sys/miscfs/genfs/layer_vnops.c')
| -rw-r--r-- | sys/miscfs/genfs/layer_vnops.c | 950 |
1 files changed, 950 insertions, 0 deletions
diff --git a/sys/miscfs/genfs/layer_vnops.c b/sys/miscfs/genfs/layer_vnops.c new file mode 100644 index 00000000000..2b644098d09 --- /dev/null +++ b/sys/miscfs/genfs/layer_vnops.c @@ -0,0 +1,950 @@ +/* $OpenBSD: layer_vnops.c,v 1.1 2003/05/12 20:58:40 tedu Exp $ */ +/* $NetBSD: layer_vnops.c,v 1.10 2001/12/06 04:29:23 chs Exp $ */ + +/* + * Copyright (c) 1999 National Aeronautics & Space Administration + * All rights reserved. + * + * This software was written by William Studenmund of the + * Numerical Aerospace Simulation Facility, NASA Ames Research Center. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the National Aeronautics & Space Administration + * nor the names of its contributors may be used to endorse or promote + * products derived from this software without specific prior written + * permission. + * + * THIS SOFTWARE IS PROVIDED BY THE NATIONAL AERONAUTICS & SPACE ADMINISTRATION + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE ADMINISTRATION OR CONTRIB- + * UTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, + * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ +/* + * Copyright (c) 1992, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * John Heidemann of the UCLA Ficus project. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * @(#)null_vnops.c 8.6 (Berkeley) 5/27/95 + * + * Ancestors: + * @(#)lofs_vnops.c 1.2 (Berkeley) 6/18/92 + * $Id: layer_vnops.c,v 1.1 2003/05/12 20:58:40 tedu Exp $ + * ...and... + * @(#)null_vnodeops.c 1.20 92/07/07 UCLA Ficus project + */ + +/* + * Null Layer vnode routines. + * + * (See mount_null(8) for more information.) + * + * The layer.h, layer_extern.h, layer_vfs.c, and layer_vnops.c files provide + * the core implimentation of the null file system and most other stacked + * fs's. The description below refers to the null file system, but the + * services provided by the layer* files are useful for all layered fs's. + * + * The null layer duplicates a portion of the file system + * name space under a new name. In this respect, it is + * similar to the loopback file system. It differs from + * the loopback fs in two respects: it is implemented using + * a stackable layers techniques, and it's "null-node"s stack above + * all lower-layer vnodes, not just over directory vnodes. + * + * The null layer has two purposes. First, it serves as a demonstration + * of layering by proving a layer which does nothing. (It actually + * does everything the loopback file system does, which is slightly + * more than nothing.) Second, the null layer can serve as a prototype + * layer. Since it provides all necessary layer framework, + * new file system layers can be created very easily be starting + * with a null layer. + * + * The remainder of the man page examines the null layer as a basis + * for constructing new layers. + * + * + * INSTANTIATING NEW NULL LAYERS + * + * New null layers are created with mount_null(8). + * Mount_null(8) takes two arguments, the pathname + * of the lower vfs (target-pn) and the pathname where the null + * layer will appear in the namespace (alias-pn). After + * the null layer is put into place, the contents + * of target-pn subtree will be aliased under alias-pn. + * + * It is conceivable that other overlay filesystems will take different + * parameters. For instance, data migration or access controll layers might + * only take one pathname which will serve both as the target-pn and + * alias-pn described above. + * + * + * OPERATION OF A NULL LAYER + * + * The null layer is the minimum file system layer, + * simply bypassing all possible operations to the lower layer + * for processing there. The majority of its activity centers + * on the bypass routine, though which nearly all vnode operations + * pass. + * + * The bypass routine accepts arbitrary vnode operations for + * handling by the lower layer. It begins by examing vnode + * operation arguments and replacing any layered nodes by their + * lower-layer equivlants. It then invokes the operation + * on the lower layer. Finally, it replaces the layered nodes + * in the arguments and, if a vnode is return by the operation, + * stacks a layered node on top of the returned vnode. + * + * The bypass routine in this file, layer_bypass(), is suitable for use + * by many different layered filesystems. It can be used by multiple + * filesystems simultaneously. Alternatively, a layered fs may provide + * its own bypass routine, in which case layer_bypass() should be used as + * a model. For instance, the main functionality provided by umapfs, the user + * identity mapping file system, is handled by a custom bypass routine. + * + * Typically a layered fs registers its selected bypass routine as the + * default vnode operation in its vnodeopv_entry_desc table. Additionally + * the filesystem must store the bypass entry point in the layerm_bypass + * field of struct layer_mount. All other layer routines in this file will + * use the layerm_bypass routine. + * + * Although the bypass routine handles most operations outright, a number + * of operations are special cased, and handled by the layered fs. One + * group, layer_setattr, layer_getattr, layer_access, layer_open, and + * layer_fsync, perform layer-specific manipulation in addition to calling + * the bypass routine. The other group + + * Although bypass handles most operations, vop_getattr, vop_lock, + * vop_unlock, vop_inactive, vop_reclaim, and vop_print are not + * bypassed. Vop_getattr must change the fsid being returned. + * Vop_lock and vop_unlock must handle any locking for the + * current vnode as well as pass the lock request down. + * Vop_inactive and vop_reclaim are not bypassed so that + * they can handle freeing null-layer specific data. Vop_print + * is not bypassed to avoid excessive debugging information. + * Also, certain vnode operations change the locking state within + * the operation (create, mknod, remove, link, rename, mkdir, rmdir, + * and symlink). Ideally these operations should not change the + * lock state, but should be changed to let the caller of the + * function unlock them. Otherwise all intermediate vnode layers + * (such as union, umapfs, etc) must catch these functions to do + * the necessary locking at their layer. + * + * + * INSTANTIATING VNODE STACKS + * + * Mounting associates the null layer with a lower layer, + * effect stacking two VFSes. Vnode stacks are instead + * created on demand as files are accessed. + * + * The initial mount creates a single vnode stack for the + * root of the new null layer. All other vnode stacks + * are created as a result of vnode operations on + * this or other null vnode stacks. + * + * New vnode stacks come into existance as a result of + * an operation which returns a vnode. + * The bypass routine stacks a null-node above the new + * vnode before returning it to the caller. + * + * For example, imagine mounting a null layer with + * "mount_null /usr/include /dev/layer/null". + * Changing directory to /dev/layer/null will assign + * the root null-node (which was created when the null layer was mounted). + * Now consider opening "sys". A vop_lookup would be + * done on the root null-node. This operation would bypass through + * to the lower layer which would return a vnode representing + * the UFS "sys". layer_bypass then builds a null-node + * aliasing the UFS "sys" and returns this to the caller. + * Later operations on the null-node "sys" will repeat this + * process when constructing other vnode stacks. + * + * + * CREATING OTHER FILE SYSTEM LAYERS + * + * One of the easiest ways to construct new file system layers is to make + * a copy of the null layer, rename all files and variables, and + * then begin modifing the copy. Sed can be used to easily rename + * all variables. + * + * The umap layer is an example of a layer descended from the + * null layer. + * + * + * INVOKING OPERATIONS ON LOWER LAYERS + * + * There are two techniques to invoke operations on a lower layer + * when the operation cannot be completely bypassed. Each method + * is appropriate in different situations. In both cases, + * it is the responsibility of the aliasing layer to make + * the operation arguments "correct" for the lower layer + * by mapping an vnode arguments to the lower layer. + * + * The first approach is to call the aliasing layer's bypass routine. + * This method is most suitable when you wish to invoke the operation + * currently being hanldled on the lower layer. It has the advantage + * that the bypass routine already must do argument mapping. + * An example of this is null_getattrs in the null layer. + * + * A second approach is to directly invoked vnode operations on + * the lower layer with the VOP_OPERATIONNAME interface. + * The advantage of this method is that it is easy to invoke + * arbitrary operations on the lower layer. The disadvantage + * is that vnodes arguments must be manualy mapped. + * + */ + + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/proc.h> +#include <sys/time.h> +#include <sys/vnode.h> +#include <sys/mount.h> +#include <sys/namei.h> +#include <sys/malloc.h> +#include <sys/buf.h> +#include <miscfs/genfs/layer.h> +#include <miscfs/genfs/layer_extern.h> + + +/* + * This is the 08-June-99 bypass routine, based on the 10-Apr-92 bypass + * routine by John Heidemann. + * The new element for this version is that the whole nullfs + * system gained the concept of locks on the lower node, and locks on + * our nodes. When returning from a call to the lower layer, we may + * need to update lock state ONLY on our layer. The LAYERFS_UPPER*LOCK() + * macros provide this functionality. + * The 10-Apr-92 version was optimized for speed, throwing away some + * safety checks. It should still always work, but it's not as + * robust to programmer errors. + * Define SAFETY to include some error checking code. + * + * In general, we map all vnodes going down and unmap them on the way back. + * + * Also, some BSD vnode operations have the side effect of vrele'ing + * their arguments. With stacking, the reference counts are held + * by the upper node, not the lower one, so we must handle these + * side-effects here. This is not of concern in Sun-derived systems + * since there are no such side-effects. + * + * New for the 08-June-99 version: we also handle operations which unlock + * the passed-in node (typically they vput the node). + * + * This makes the following assumptions: + * - only one returned vpp + * - no INOUT vpp's (Sun's vop_open has one of these) + * - the vnode operation vector of the first vnode should be used + * to determine what implementation of the op should be invoked + * - all mapped vnodes are of our vnode-type (NEEDSWORK: + * problems on rmdir'ing mount points and renaming?) + */ +int +layer_bypass(v) + void *v; +{ + struct vop_generic_args /* { + struct vnodeop_desc *a_desc; + <other random data follows, presumably> + } */ *ap = v; + int (**our_vnodeop_p)(void *); + struct vnode **this_vp_p; + int error, error1; + struct vnode *old_vps[VDESC_MAX_VPS], *vp0; + struct vnode **vps_p[VDESC_MAX_VPS]; + struct vnode ***vppp; + struct vnodeop_desc *descp = ap->a_desc; + int reles, i, flags; + +#ifdef SAFETY + /* + * We require at least one vp. + */ + if (descp->vdesc_vp_offsets == NULL || + descp->vdesc_vp_offsets[0] == VDESC_NO_OFFSET) + panic ("layer_bypass: no vp's in map.\n"); +#endif + + vps_p[0] = VOPARG_OFFSETTO(struct vnode**,descp->vdesc_vp_offsets[0],ap); + vp0 = *vps_p[0]; + flags = MOUNTTOLAYERMOUNT(vp0->v_mount)->layerm_flags; + our_vnodeop_p = vp0->v_op; + + if (flags & LAYERFS_MBYPASSDEBUG) + printf ("layer_bypass: %s\n", descp->vdesc_name); + + /* + * Map the vnodes going in. + * Later, we'll invoke the operation based on + * the first mapped vnode's operation vector. + */ + reles = descp->vdesc_flags; + for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) { + if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET) + break; /* bail out at end of list */ + vps_p[i] = this_vp_p = + VOPARG_OFFSETTO(struct vnode**,descp->vdesc_vp_offsets[i],ap); + /* + * We're not guaranteed that any but the first vnode + * are of our type. Check for and don't map any + * that aren't. (We must always map first vp or vclean fails.) + */ + if (i && (*this_vp_p == NULL || + (*this_vp_p)->v_op != our_vnodeop_p)) { + old_vps[i] = NULL; + } else { + old_vps[i] = *this_vp_p; + *(vps_p[i]) = LAYERVPTOLOWERVP(*this_vp_p); + /* + * XXX - Several operations have the side effect + * of vrele'ing their vp's. We must account for + * that. (This should go away in the future.) + */ + if (reles & VDESC_VP0_WILLRELE) + VREF(*this_vp_p); + } + + } + + /* + * Call the operation on the lower layer + * with the modified argument structure. + */ + error = VCALL(*vps_p[0], descp->vdesc_offset, ap); + + /* + * Maintain the illusion of call-by-value + * by restoring vnodes in the argument structure + * to their original value. + */ + reles = descp->vdesc_flags; + for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) { + if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET) + break; /* bail out at end of list */ + if (old_vps[i]) { + *(vps_p[i]) = old_vps[i]; + if (reles & VDESC_VP0_WILLUNLOCK) + LAYERFS_UPPERUNLOCK(*(vps_p[i]), 0, error1); + if (reles & VDESC_VP0_WILLRELE) + vrele(*(vps_p[i])); + } + } + + /* + * Map the possible out-going vpp + * (Assumes that the lower layer always returns + * a VREF'ed vpp unless it gets an error.) + */ + if (descp->vdesc_vpp_offset != VDESC_NO_OFFSET && + !(descp->vdesc_flags & VDESC_NOMAP_VPP) && + !error) { + /* + * XXX - even though some ops have vpp returned vp's, + * several ops actually vrele this before returning. + * We must avoid these ops. + * (This should go away when these ops are regularized.) + */ + if (descp->vdesc_flags & VDESC_VPP_WILLRELE) + goto out; + vppp = VOPARG_OFFSETTO(struct vnode***, + descp->vdesc_vpp_offset,ap); + /* + * Only vop_lookup, vop_create, vop_makedir, vop_bmap, + * vop_mknod, and vop_symlink return vpp's. vop_bmap + * doesn't call bypass as the lower vpp is fine (we're just + * going to do i/o on it). vop_loookup doesn't call bypass + * as a lookup on "." would generate a locking error. + * So all the calls which get us here have a locked vpp. :-) + */ + error = layer_node_create(old_vps[0]->v_mount, **vppp, *vppp); + } + + out: + return (error); +} + +/* + * We have to carry on the locking protocol on the layer vnodes + * as we progress through the tree. We also have to enforce read-only + * if this layer is mounted read-only. + */ +int +layer_lookup(v) + void *v; +{ + struct vop_lookup_args /* { + struct vnodeop_desc *a_desc; + struct vnode * a_dvp; + struct vnode ** a_vpp; + struct componentname * a_cnp; + } */ *ap = v; + struct componentname *cnp = ap->a_cnp; + int flags = cnp->cn_flags; + struct vnode *dvp, *vp, *ldvp; + int error, r; + + dvp = ap->a_dvp; + *ap->a_vpp = NULL; + + if ((flags & ISLASTCN) && (dvp->v_mount->mnt_flag & MNT_RDONLY) && + (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) + return (EROFS); + + ldvp = LAYERVPTOLOWERVP(dvp); + ap->a_dvp = ldvp; + error = VCALL(ldvp, ap->a_desc->vdesc_offset, ap); + vp = *ap->a_vpp; + + if (error == EJUSTRETURN && (flags & ISLASTCN) && + (dvp->v_mount->mnt_flag & MNT_RDONLY) && + (cnp->cn_nameiop == CREATE || cnp->cn_nameiop == RENAME)) + error = EROFS; + /* + * We must do the same locking and unlocking at this layer as + * is done in the layers below us. It used to be we would try + * to guess based on what was set with the flags and error codes. + * + * But that doesn't work. So now we have the underlying VOP_LOOKUP + * tell us if it released the parent vnode, and we adjust the + * upper node accordingly. We can't just look at the lock states + * of the lower nodes as someone else might have come along and + * locked the parent node after our call to VOP_LOOKUP locked it. + */ + if ((cnp->cn_flags & PDIRUNLOCK)) { + LAYERFS_UPPERUNLOCK(dvp, 0, r); + } + if (ldvp == vp) { + /* + * Did lookup on "." or ".." in the root node of a mount point. + * So we return dvp after a VREF. + */ + *ap->a_vpp = dvp; + VREF(dvp); + vrele(vp); + } else if (vp != NULL) { + error = layer_node_create(dvp->v_mount, vp, ap->a_vpp); + } + return (error); +} + +/* + * Setattr call. Disallow write attempts if the layer is mounted read-only. + */ +int +layer_setattr(v) + void *v; +{ + struct vop_setattr_args /* { + struct vnodeop_desc *a_desc; + struct vnode *a_vp; + struct vattr *a_vap; + struct ucred *a_cred; + struct proc *a_p; + } */ *ap = v; + struct vnode *vp = ap->a_vp; + struct vattr *vap = ap->a_vap; + + if ((vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL || + vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL || + vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL) && + (vp->v_mount->mnt_flag & MNT_RDONLY)) + return (EROFS); + if (vap->va_size != VNOVAL) { + switch (vp->v_type) { + case VDIR: + return (EISDIR); + case VCHR: + case VBLK: + case VSOCK: + case VFIFO: + return (0); + case VREG: + case VLNK: + default: + /* + * Disallow write attempts if the filesystem is + * mounted read-only. + */ + if (vp->v_mount->mnt_flag & MNT_RDONLY) + return (EROFS); + } + } + return (LAYERFS_DO_BYPASS(vp, ap)); +} + +/* + * We handle getattr only to change the fsid. + */ +int +layer_getattr(v) + void *v; +{ + struct vop_getattr_args /* { + struct vnode *a_vp; + struct vattr *a_vap; + struct ucred *a_cred; + struct proc *a_p; + } */ *ap = v; + struct vnode *vp = ap->a_vp; + int error; + + if ((error = LAYERFS_DO_BYPASS(vp, ap)) != 0) + return (error); + /* Requires that arguments be restored. */ + ap->a_vap->va_fsid = vp->v_mount->mnt_stat.f_fsid.val[0]; + return (0); +} + +int +layer_access(v) + void *v; +{ + struct vop_access_args /* { + struct vnode *a_vp; + int a_mode; + struct ucred *a_cred; + struct proc *a_p; + } */ *ap = v; + struct vnode *vp = ap->a_vp; + mode_t mode = ap->a_mode; + + /* + * Disallow write attempts on read-only layers; + * unless the file is a socket, fifo, or a block or + * character device resident on the file system. + */ + if (mode & VWRITE) { + switch (vp->v_type) { + case VDIR: + case VLNK: + case VREG: + if (vp->v_mount->mnt_flag & MNT_RDONLY) + return (EROFS); + break; + default: + break; + } + } + return (LAYERFS_DO_BYPASS(vp, ap)); +} + +/* + * We must handle open to be able to catch MNT_NODEV and friends. + */ +int +layer_open(v) + void *v; +{ + struct vop_open_args *ap = v; + struct vnode *vp = ap->a_vp; + enum vtype lower_type = LAYERVPTOLOWERVP(vp)->v_type; + + if (((lower_type == VBLK) || (lower_type == VCHR)) && + (vp->v_mount->mnt_flag & MNT_NODEV)) + return ENXIO; + + return LAYERFS_DO_BYPASS(vp, ap); +} + +/* + * We need to process our own vnode lock and then clear the + * interlock flag as it applies only to our vnode, not the + * vnodes below us on the stack. + */ +int +layer_lock(v) + void *v; +{ + struct vop_lock_args /* { + struct vnode *a_vp; + int a_flags; + struct proc *a_p; + } */ *ap = v; + struct vnode *vp = ap->a_vp, *lowervp; + int flags = ap->a_flags, error; + struct proc *p = ap->a_p; + + if (vp->v_flag & VXLOCK) /* XXX this is a disaster -tedu XXX */ + return (0); + + if (vp->v_vnlock != NULL) { + /* + * The lower level has exported a struct lock to us. Use + * it so that all vnodes in the stack lock and unlock + * simultaneously. Note: we don't DRAIN the lock as DRAIN + * decommissions the lock - just because our vnode is + * going away doesn't mean the struct lock below us is. + * LK_EXCLUSIVE is fine. + */ + if ((flags & LK_TYPE_MASK) == LK_DRAIN) + return (lockmgr(vp->v_vnlock, (flags & ~LK_TYPE_MASK) | + LK_EXCLUSIVE, &vp->v_interlock, p)); + else + return (lockmgr(vp->v_vnlock, flags, &vp->v_interlock, p)); + } else { + /* + * Ahh well. It would be nice if the fs we're over would + * export a struct lock for us to use, but it doesn't. + * + * To prevent race conditions involving doing a lookup + * on "..", we have to lock the lower node, then lock our + * node. Most of the time it won't matter that we lock our + * node (as any locking would need the lower one locked + * first). But we can LK_DRAIN the upper lock as a step + * towards decomissioning it. + */ + lowervp = LAYERVPTOLOWERVP(vp); + if (flags & LK_INTERLOCK) { + simple_unlock(&vp->v_interlock); + flags &= ~LK_INTERLOCK; + } + if ((flags & LK_TYPE_MASK) == LK_DRAIN) { + error = VOP_LOCK(lowervp, (flags & ~LK_TYPE_MASK) | + LK_EXCLUSIVE, p); + } else { + error = VOP_LOCK(lowervp, flags, p); + } + if (error) + return (error); + if ((error = lockmgr(&vp->v_lock, flags, &vp->v_interlock, p))) { + VOP_UNLOCK(lowervp, 0, p); + } + return (error); + } +} + +/* + */ +int +layer_unlock(v) + void *v; +{ + struct vop_unlock_args /* { + struct vnode *a_vp; + int a_flags; + struct proc *a_p; + } */ *ap = v; + struct vnode *vp = ap->a_vp; + int flags = ap->a_flags; + struct proc *p = ap->a_p; + + if (vp->v_flag & VXLOCK) + return (0); + + if (vp->v_vnlock != NULL) { + return (lockmgr(vp->v_vnlock, ap->a_flags | LK_RELEASE, + &vp->v_interlock, p)); + } else { + if (flags & LK_INTERLOCK) { + simple_unlock(&vp->v_interlock); + flags &= ~LK_INTERLOCK; + } + VOP_UNLOCK(LAYERVPTOLOWERVP(vp), flags, p); + return (lockmgr(&vp->v_lock, ap->a_flags | LK_RELEASE, + &vp->v_interlock, p)); + } +} + +/* + * As long as genfs_nolock is in use, don't call VOP_ISLOCKED(lowervp) + * if vp->v_vnlock == NULL as genfs_noislocked will always report 0. + */ +int +layer_islocked(v) + void *v; +{ + struct vop_islocked_args /* { + struct vnode *a_vp; + } */ *ap = v; + struct vnode *vp = ap->a_vp; + + if (vp->v_vnlock != NULL) + return (lockstatus(vp->v_vnlock)); + else + return (lockstatus(&vp->v_lock)); +} + +/* + * If vinvalbuf is calling us, it's a "shallow fsync" -- don't bother + * syncing the underlying vnodes, since they'll be fsync'ed when + * reclaimed; otherwise, + * pass it through to the underlying layer. + * + * XXX Do we still need to worry about shallow fsync? + */ + +int +layer_fsync(v) + void *v; +{ + struct vop_fsync_args /* { + struct vnode *a_vp; + struct ucred *a_cred; + int a_flags; + off_t offlo; + off_t offhi; + struct proc *a_p; + } */ *ap = v; + + return (LAYERFS_DO_BYPASS(ap->a_vp, ap)); +} + + +int +layer_inactive(v) + void *v; +{ + struct vop_inactive_args /* { + struct vnode *a_vp; + struct proc *a_p; + } */ *ap = v; + struct vnode *vp = ap->a_vp; + struct proc *p = ap->a_p; + + /* + * Do nothing (and _don't_ bypass). + * Wait to vrele lowervp until reclaim, + * so that until then our layer_node is in the + * cache and reusable. + * + * NEEDSWORK: Someday, consider inactive'ing + * the lowervp and then trying to reactivate it + * with capabilities (v_id) + * like they do in the name lookup cache code. + * That's too much work for now. + */ + VOP_UNLOCK(vp, 0, p); + + /* ..., but don't cache the device node. */ + if (vp->v_type == VBLK || vp->v_type == VCHR) + vgone(vp); + return (0); +} + +int +layer_reclaim(v) + void *v; +{ + struct vop_reclaim_args /* { + struct vnode *a_vp; + struct proc *a_p; + } */ *ap = v; + struct vnode *vp = ap->a_vp; + struct layer_mount *lmp = MOUNTTOLAYERMOUNT(vp->v_mount); + struct layer_node *xp = VTOLAYER(vp); + struct vnode *lowervp = xp->layer_lowervp; + + /* + * Note: in vop_reclaim, the node's struct lock has been + * decomissioned, so we have to be careful about calling + * VOP's on ourself. Even if we turned a LK_DRAIN into an + * LK_EXCLUSIVE in layer_lock, we still must be careful as VXLOCK is + * set. + */ + /* After this assignment, this node will not be re-used. */ + if ((vp == lmp->layerm_rootvp)) { + /* + * Oops! We no longer have a root node. Most likely reason is + * that someone forcably unmunted the underlying fs. + * + * Now getting the root vnode will fail. We're dead. :-( + */ + lmp->layerm_rootvp = NULL; + } + xp->layer_lowervp = NULL; + simple_lock(&lmp->layerm_hashlock); + LIST_REMOVE(xp, layer_hash); + simple_unlock(&lmp->layerm_hashlock); + FREE(vp->v_data, M_TEMP); + vp->v_data = NULL; + vrele (lowervp); + return (0); +} + +/* + * We just feed the returned vnode up to the caller - there's no need + * to build a layer node on top of the node on which we're going to do + * i/o. :-) + */ +int +layer_bmap(v) + void *v; +{ + struct vop_bmap_args /* { + struct vnode *a_vp; + daddr_t a_bn; + struct vnode **a_vpp; + daddr_t *a_bnp; + int *a_runp; + } */ *ap = v; + struct vnode *vp; + + ap->a_vp = vp = LAYERVPTOLOWERVP(ap->a_vp); + + return (VCALL(vp, ap->a_desc->vdesc_offset, ap)); +} + +int +layer_print(v) + void *v; +{ + struct vop_print_args /* { + struct vnode *a_vp; + } */ *ap = v; + struct vnode *vp = ap->a_vp; + printf ("\ttag VT_LAYERFS, vp=%p, lowervp=%p\n", vp, LAYERVPTOLOWERVP(vp)); + VOP_PRINT(LAYERVPTOLOWERVP(vp)); + return (0); +} + +/* + * XXX - vop_strategy must be hand coded because it has no + * vnode in its arguments. + * This goes away with a merged VM/buffer cache. + */ +int +layer_strategy(v) + void *v; +{ + struct vop_strategy_args /* { + struct buf *a_bp; + } */ *ap = v; + struct buf *bp = ap->a_bp; + int error; + struct vnode *savedvp; + + savedvp = bp->b_vp; + bp->b_vp = LAYERVPTOLOWERVP(bp->b_vp); + + error = VOP_STRATEGY(bp); + + bp->b_vp = savedvp; + + return (error); +} + +/* + * XXX - like vop_strategy, vop_bwrite must be hand coded because it has no + * vnode in its arguments. + * This goes away with a merged VM/buffer cache. + */ +int +layer_bwrite(v) + void *v; +{ + struct vop_bwrite_args /* { + struct buf *a_bp; + } */ *ap = v; + struct buf *bp = ap->a_bp; + int error; + struct vnode *savedvp; + + savedvp = bp->b_vp; + bp->b_vp = LAYERVPTOLOWERVP(bp->b_vp); + + error = VOP_BWRITE(bp); + + bp->b_vp = savedvp; + + return (error); +} + +#if 0 +int +layer_getpages(v) + void *v; +{ + struct vop_getpages_args /* { + struct vnode *a_vp; + voff_t a_offset; + struct vm_page **a_m; + int *a_count; + int a_centeridx; + vm_prot_t a_access_type; + int a_advice; + int a_flags; + } */ *ap = v; + struct vnode *vp = ap->a_vp; + int error; + + /* + * just pass the request on to the underlying layer. + */ + + if (ap->a_flags & PGO_LOCKED) { + return EBUSY; + } + ap->a_vp = LAYERVPTOLOWERVP(vp); + simple_unlock(&vp->v_interlock); + simple_lock(&ap->a_vp->v_interlock); + error = VCALL(ap->a_vp, VOFFSET(vop_getpages), ap); + return error; +} + +int +layer_putpages(v) + void *v; +{ + struct vop_putpages_args /* { + struct vnode *a_vp; + voff_t a_offlo; + voff_t a_offhi; + int a_flags; + } */ *ap = v; + struct vnode *vp = ap->a_vp; + int error; + + /* + * just pass the request on to the underlying layer. + */ + + ap->a_vp = LAYERVPTOLOWERVP(vp); + simple_unlock(&vp->v_interlock); + simple_lock(&ap->a_vp->v_interlock); + error = VCALL(ap->a_vp, VOFFSET(vop_putpages), ap); + return error; +} +#endif |