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Diffstat (limited to 'sys/fs/unionfs/union_vnops.c')
| -rw-r--r-- | sys/fs/unionfs/union_vnops.c | 1495 |
1 files changed, 1495 insertions, 0 deletions
diff --git a/sys/fs/unionfs/union_vnops.c b/sys/fs/unionfs/union_vnops.c new file mode 100644 index 0000000..96327b0 --- /dev/null +++ b/sys/fs/unionfs/union_vnops.c @@ -0,0 +1,1495 @@ +/* + * Copyright (c) 1992, 1993, 1994 The Regents of the University of California. + * Copyright (c) 1992, 1993, 1994 Jan-Simon Pendry. + * All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Jan-Simon Pendry. + * + * 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. + * + * @(#)union_vnops.c 8.6 (Berkeley) 2/17/94 + */ + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/proc.h> +#include <sys/file.h> +#include <sys/time.h> +#include <sys/types.h> +#include <sys/vnode.h> +#include <sys/mount.h> +#include <sys/namei.h> +#include <sys/malloc.h> +#include <sys/buf.h> +#include <sys/queue.h> +#include <miscfs/union/union.h> + +#define FIXUP(un) { \ + if (((un)->un_flags & UN_ULOCK) == 0) { \ + union_fixup(un); \ + } \ +} + +static void +union_fixup(un) + struct union_node *un; +{ + + VOP_LOCK(un->un_uppervp); + un->un_flags |= UN_ULOCK; +} + +static int +union_lookup1(udvp, dvp, vpp, cnp) + struct vnode *udvp; + struct vnode *dvp; + struct vnode **vpp; + struct componentname *cnp; +{ + int error; + struct vnode *tdvp; + struct mount *mp; + + /* + * If stepping up the directory tree, check for going + * back across the mount point, in which case do what + * lookup would do by stepping back down the mount + * hierarchy. + */ + if (cnp->cn_flags & ISDOTDOT) { + for (;;) { + /* + * Don't do the NOCROSSMOUNT check + * at this level. By definition, + * union fs deals with namespaces, not + * filesystems. + */ + if ((dvp->v_flag & VROOT) == 0) + break; + + tdvp = dvp; + dvp = dvp->v_mount->mnt_vnodecovered; + vput(tdvp); + VREF(dvp); + VOP_LOCK(dvp); + } + } + + error = VOP_LOOKUP(dvp, &tdvp, cnp); + if (error) + return (error); + + /* + * The parent directory will have been unlocked, unless lookup + * found the last component. In which case, re-lock the node + * here to allow it to be unlocked again (phew) in union_lookup. + */ + if (dvp != tdvp && !(cnp->cn_flags & ISLASTCN)) + VOP_LOCK(dvp); + + dvp = tdvp; + + /* + * Lastly check if the current node is a mount point in + * which case walk up the mount hierarchy making sure not to + * bump into the root of the mount tree (ie. dvp != udvp). + */ + while (dvp != udvp && (dvp->v_type == VDIR) && + (mp = dvp->v_mountedhere)) { + + if (mp->mnt_flag & MNT_MLOCK) { + mp->mnt_flag |= MNT_MWAIT; + sleep((caddr_t) mp, PVFS); + continue; + } + + if (error = VFS_ROOT(mp, &tdvp)) { + vput(dvp); + return (error); + } + + vput(dvp); + dvp = tdvp; + } + + *vpp = dvp; + return (0); +} + +int +union_lookup(ap) + struct vop_lookup_args /* { + struct vnodeop_desc *a_desc; + struct vnode *a_dvp; + struct vnode **a_vpp; + struct componentname *a_cnp; + } */ *ap; +{ + int error; + int uerror, lerror; + struct vnode *uppervp, *lowervp; + struct vnode *upperdvp, *lowerdvp; + struct vnode *dvp = ap->a_dvp; + struct union_node *dun = VTOUNION(dvp); + struct componentname *cnp = ap->a_cnp; + int lockparent = cnp->cn_flags & LOCKPARENT; + int rdonly = cnp->cn_flags & RDONLY; + struct union_mount *um = MOUNTTOUNIONMOUNT(dvp->v_mount); + struct ucred *saved_cred; + + cnp->cn_flags |= LOCKPARENT; + + upperdvp = dun->un_uppervp; + lowerdvp = dun->un_lowervp; + uppervp = NULLVP; + lowervp = NULLVP; + + /* + * do the lookup in the upper level. + * if that level comsumes additional pathnames, + * then assume that something special is going + * on and just return that vnode. + */ + if (upperdvp) { + FIXUP(dun); + uerror = union_lookup1(um->um_uppervp, upperdvp, + &uppervp, cnp); + /*if (uppervp == upperdvp) + dun->un_flags |= UN_KLOCK;*/ + + if (cnp->cn_consume != 0) { + *ap->a_vpp = uppervp; + if (!lockparent) + cnp->cn_flags &= ~LOCKPARENT; + return (uerror); + } + } else { + uerror = ENOENT; + } + + /* + * in a similar way to the upper layer, do the lookup + * in the lower layer. this time, if there is some + * component magic going on, then vput whatever we got + * back from the upper layer and return the lower vnode + * instead. + */ + if (lowerdvp) { + int nameiop; + + VOP_LOCK(lowerdvp); + + /* + * Only do a LOOKUP on the bottom node, since + * we won't be making changes to it anyway. + */ + nameiop = cnp->cn_nameiop; + cnp->cn_nameiop = LOOKUP; + if (um->um_op == UNMNT_BELOW) { + saved_cred = cnp->cn_cred; + cnp->cn_cred = um->um_cred; + } + lerror = union_lookup1(um->um_lowervp, lowerdvp, + &lowervp, cnp); + if (um->um_op == UNMNT_BELOW) + cnp->cn_cred = saved_cred; + cnp->cn_nameiop = nameiop; + + if (lowervp != lowerdvp) + VOP_UNLOCK(lowerdvp); + + if (cnp->cn_consume != 0) { + if (uppervp) { + if (uppervp == upperdvp) + vrele(uppervp); + else + vput(uppervp); + uppervp = NULLVP; + } + *ap->a_vpp = lowervp; + if (!lockparent) + cnp->cn_flags &= ~LOCKPARENT; + return (lerror); + } + } else { + lerror = ENOENT; + } + + if (!lockparent) + cnp->cn_flags &= ~LOCKPARENT; + + /* + * at this point, we have uerror and lerror indicating + * possible errors with the lookups in the upper and lower + * layers. additionally, uppervp and lowervp are (locked) + * references to existing vnodes in the upper and lower layers. + * + * there are now three cases to consider. + * 1. if both layers returned an error, then return whatever + * error the upper layer generated. + * + * 2. if the top layer failed and the bottom layer succeeded + * then two subcases occur. + * a. the bottom vnode is not a directory, in which + * case just return a new union vnode referencing + * an empty top layer and the existing bottom layer. + * b. the bottom vnode is a directory, in which case + * create a new directory in the top-level and + * continue as in case 3. + * + * 3. if the top layer succeeded then return a new union + * vnode referencing whatever the new top layer and + * whatever the bottom layer returned. + */ + + *ap->a_vpp = NULLVP; + + /* case 1. */ + if ((uerror != 0) && (lerror != 0)) { + return (uerror); + } + + /* case 2. */ + if (uerror != 0 /* && (lerror == 0) */ ) { + if (lowervp->v_type == VDIR) { /* case 2b. */ + dun->un_flags &= ~UN_ULOCK; + VOP_UNLOCK(upperdvp); + uerror = union_mkshadow(um, upperdvp, cnp, &uppervp); + VOP_LOCK(upperdvp); + dun->un_flags |= UN_ULOCK; + + if (uerror) { + if (lowervp) { + vput(lowervp); + lowervp = NULLVP; + } + return (uerror); + } + } + } + + if (lowervp) + VOP_UNLOCK(lowervp); + + error = union_allocvp(ap->a_vpp, dvp->v_mount, dvp, upperdvp, cnp, + uppervp, lowervp); + + if (error) { + if (uppervp) + vput(uppervp); + if (lowervp) + vrele(lowervp); + } else { + if (*ap->a_vpp != dvp) + if (!lockparent || !(cnp->cn_flags & ISLASTCN)) + VOP_UNLOCK(dvp); + } + + return (error); +} + +int +union_create(ap) + struct vop_create_args /* { + struct vnode *a_dvp; + struct vnode **a_vpp; + struct componentname *a_cnp; + struct vattr *a_vap; + } */ *ap; +{ + struct union_node *un = VTOUNION(ap->a_dvp); + struct vnode *dvp = un->un_uppervp; + + if (dvp) { + int error; + struct vnode *vp; + + FIXUP(un); + + VREF(dvp); + un->un_flags |= UN_KLOCK; + vput(ap->a_dvp); + error = VOP_CREATE(dvp, &vp, ap->a_cnp, ap->a_vap); + if (error) + return (error); + + error = union_allocvp( + ap->a_vpp, + ap->a_dvp->v_mount, + ap->a_dvp, + NULLVP, + ap->a_cnp, + vp, + NULLVP); + if (error) + vput(vp); + return (error); + } + + vput(ap->a_dvp); + return (EROFS); +} + +int +union_mknod(ap) + struct vop_mknod_args /* { + struct vnode *a_dvp; + struct vnode **a_vpp; + struct componentname *a_cnp; + struct vattr *a_vap; + } */ *ap; +{ + struct union_node *un = VTOUNION(ap->a_dvp); + struct vnode *dvp = un->un_uppervp; + + if (dvp) { + int error; + struct vnode *vp; + + FIXUP(un); + + VREF(dvp); + un->un_flags |= UN_KLOCK; + vput(ap->a_dvp); + error = VOP_MKNOD(dvp, &vp, ap->a_cnp, ap->a_vap); + if (error) + return (error); + + if (vp) { + error = union_allocvp( + ap->a_vpp, + ap->a_dvp->v_mount, + ap->a_dvp, + NULLVP, + ap->a_cnp, + vp, + NULLVP); + if (error) + vput(vp); + } + return (error); + } + + vput(ap->a_dvp); + return (EROFS); +} + +int +union_open(ap) + struct vop_open_args /* { + struct vnodeop_desc *a_desc; + struct vnode *a_vp; + int a_mode; + struct ucred *a_cred; + struct proc *a_p; + } */ *ap; +{ + struct union_node *un = VTOUNION(ap->a_vp); + struct vnode *tvp; + int mode = ap->a_mode; + struct ucred *cred = ap->a_cred; + struct proc *p = ap->a_p; + int error; + + /* + * If there is an existing upper vp then simply open that. + */ + tvp = un->un_uppervp; + if (tvp == NULLVP) { + /* + * If the lower vnode is being opened for writing, then + * copy the file contents to the upper vnode and open that, + * otherwise can simply open the lower vnode. + */ + tvp = un->un_lowervp; + if ((ap->a_mode & FWRITE) && (tvp->v_type == VREG)) { + struct vnode *vp; + int i; + + /* + * Open the named file in the upper layer. Note that + * the file may have come into existence *since* the + * lookup was done, since the upper layer may really + * be a loopback mount of some other filesystem... + * so open the file with exclusive create and barf if + * it already exists. + * XXX - perhaps should re-lookup the node (once more + * with feeling) and simply open that. Who knows. + */ + error = union_vn_create(&vp, un, p); + if (error) + return (error); + + /* at this point, uppervp is locked */ + union_newupper(un, vp); + un->un_flags |= UN_ULOCK; + + /* + * Now, if the file is being opened with truncation, + * then the (new) upper vnode is ready to fly, + * otherwise the data from the lower vnode must be + * copied to the upper layer first. This only works + * for regular files (check is made above). + */ + if ((mode & O_TRUNC) == 0) { + /* + * XXX - should not ignore errors + * from VOP_CLOSE + */ + VOP_LOCK(tvp); + error = VOP_OPEN(tvp, FREAD, cred, p); + if (error == 0) { + error = union_copyfile(p, cred, + tvp, un->un_uppervp); + VOP_UNLOCK(tvp); + (void) VOP_CLOSE(tvp, FREAD); + } else { + VOP_UNLOCK(tvp); + } + +#ifdef UNION_DIAGNOSTIC + if (!error) + uprintf("union: copied up %s\n", + un->un_path); +#endif + } + + un->un_flags &= ~UN_ULOCK; + VOP_UNLOCK(un->un_uppervp); + union_vn_close(un->un_uppervp, FWRITE, cred, p); + VOP_LOCK(un->un_uppervp); + un->un_flags |= UN_ULOCK; + + /* + * Subsequent IOs will go to the top layer, so + * call close on the lower vnode and open on the + * upper vnode to ensure that the filesystem keeps + * its references counts right. This doesn't do + * the right thing with (cred) and (FREAD) though. + * Ignoring error returns is not righ, either. + */ + for (i = 0; i < un->un_openl; i++) { + (void) VOP_CLOSE(tvp, FREAD); + (void) VOP_OPEN(un->un_uppervp, FREAD, cred, p); + } + un->un_openl = 0; + + if (error == 0) + error = VOP_OPEN(un->un_uppervp, mode, cred, p); + return (error); + } + + /* + * Just open the lower vnode + */ + un->un_openl++; + VOP_LOCK(tvp); + error = VOP_OPEN(tvp, mode, cred, p); + VOP_UNLOCK(tvp); + + return (error); + } + + FIXUP(un); + + error = VOP_OPEN(tvp, mode, cred, p); + + return (error); +} + +int +union_close(ap) + struct vop_close_args /* { + struct vnode *a_vp; + int a_fflag; + struct ucred *a_cred; + struct proc *a_p; + } */ *ap; +{ + struct union_node *un = VTOUNION(ap->a_vp); + struct vnode *vp; + + if (un->un_uppervp) { + vp = un->un_uppervp; + } else { +#ifdef UNION_DIAGNOSTIC + if (un->un_openl <= 0) + panic("union: un_openl cnt"); +#endif + --un->un_openl; + vp = un->un_lowervp; + } + + return (VOP_CLOSE(vp, ap->a_fflag, ap->a_cred, ap->a_p)); +} + +/* + * Check access permission on the union vnode. + * The access check being enforced is to check + * against both the underlying vnode, and any + * copied vnode. This ensures that no additional + * file permissions are given away simply because + * the user caused an implicit file copy. + */ +int +union_access(ap) + struct vop_access_args /* { + struct vnodeop_desc *a_desc; + struct vnode *a_vp; + int a_mode; + struct ucred *a_cred; + struct proc *a_p; + } */ *ap; +{ + struct union_node *un = VTOUNION(ap->a_vp); + int error = EACCES; + struct vnode *vp; + + if (vp = un->un_uppervp) { + FIXUP(un); + return (VOP_ACCESS(vp, ap->a_mode, ap->a_cred, ap->a_p)); + } + + if (vp = un->un_lowervp) { + VOP_LOCK(vp); + error = VOP_ACCESS(vp, ap->a_mode, ap->a_cred, ap->a_p); + if (error == 0) { + struct union_mount *um = MOUNTTOUNIONMOUNT(vp->v_mount); + + if (um->um_op == UNMNT_BELOW) + error = VOP_ACCESS(vp, ap->a_mode, + um->um_cred, ap->a_p); + } + VOP_UNLOCK(vp); + if (error) + return (error); + } + + return (error); +} + +/* + * We handle getattr only to change the fsid. + */ +int +union_getattr(ap) + struct vop_getattr_args /* { + struct vnode *a_vp; + struct vattr *a_vap; + struct ucred *a_cred; + struct proc *a_p; + } */ *ap; +{ + int error; + struct union_node *un = VTOUNION(ap->a_vp); + struct vnode *vp = un->un_uppervp; + struct vattr *vap; + struct vattr va; + + + /* + * Some programs walk the filesystem hierarchy by counting + * links to directories to avoid stat'ing all the time. + * This means the link count on directories needs to be "correct". + * The only way to do that is to call getattr on both layers + * and fix up the link count. The link count will not necessarily + * be accurate but will be large enough to defeat the tree walkers. + */ + + vap = ap->a_vap; + + vp = un->un_uppervp; + if (vp != NULLVP) { + FIXUP(un); + error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p); + if (error) + return (error); + } + + if (vp == NULLVP) { + vp = un->un_lowervp; + } else if (vp->v_type == VDIR) { + vp = un->un_lowervp; + vap = &va; + } else { + vp = NULLVP; + } + + if (vp != NULLVP) { + VOP_LOCK(vp); + error = VOP_GETATTR(vp, vap, ap->a_cred, ap->a_p); + VOP_UNLOCK(vp); + if (error) + return (error); + } + + if ((vap != ap->a_vap) && (vap->va_type == VDIR)) + ap->a_vap->va_nlink += vap->va_nlink; + + vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0]; + return (0); +} + +int +union_setattr(ap) + struct vop_setattr_args /* { + struct vnode *a_vp; + struct vattr *a_vap; + struct ucred *a_cred; + struct proc *a_p; + } */ *ap; +{ + struct union_node *un = VTOUNION(ap->a_vp); + int error; + + /* + * Handle case of truncating lower object to zero size, + * by creating a zero length upper object. This is to + * handle the case of open with O_TRUNC and O_CREAT. + */ + if ((un->un_uppervp == NULLVP) && + /* assert(un->un_lowervp != NULLVP) */ + (un->un_lowervp->v_type == VREG) && + (ap->a_vap->va_size == 0)) { + struct vnode *vp; + + error = union_vn_create(&vp, un, ap->a_p); + if (error) + return (error); + + /* at this point, uppervp is locked */ + union_newupper(un, vp); + + VOP_UNLOCK(vp); + union_vn_close(un->un_uppervp, FWRITE, ap->a_cred, ap->a_p); + VOP_LOCK(vp); + un->un_flags |= UN_ULOCK; + } + + /* + * Try to set attributes in upper layer, + * otherwise return read-only filesystem error. + */ + if (un->un_uppervp != NULLVP) { + FIXUP(un); + error = VOP_SETATTR(un->un_uppervp, ap->a_vap, + ap->a_cred, ap->a_p); + } else { + error = EROFS; + } + + return (error); +} + +int +union_read(ap) + struct vop_read_args /* { + struct vnode *a_vp; + struct uio *a_uio; + int a_ioflag; + struct ucred *a_cred; + } */ *ap; +{ + int error; + struct vnode *vp = OTHERVP(ap->a_vp); + int dolock = (vp == LOWERVP(ap->a_vp)); + + if (dolock) + VOP_LOCK(vp); + else + FIXUP(VTOUNION(ap->a_vp)); + error = VOP_READ(vp, ap->a_uio, ap->a_ioflag, ap->a_cred); + if (dolock) + VOP_UNLOCK(vp); + + return (error); +} + +int +union_write(ap) + struct vop_read_args /* { + struct vnode *a_vp; + struct uio *a_uio; + int a_ioflag; + struct ucred *a_cred; + } */ *ap; +{ + int error; + struct vnode *vp = OTHERVP(ap->a_vp); + int dolock = (vp == LOWERVP(ap->a_vp)); + + if (dolock) + VOP_LOCK(vp); + else + FIXUP(VTOUNION(ap->a_vp)); + error = VOP_WRITE(vp, ap->a_uio, ap->a_ioflag, ap->a_cred); + if (dolock) + VOP_UNLOCK(vp); + + return (error); +} + +int +union_ioctl(ap) + struct vop_ioctl_args /* { + struct vnode *a_vp; + int a_command; + caddr_t a_data; + int a_fflag; + struct ucred *a_cred; + struct proc *a_p; + } */ *ap; +{ + + return (VOP_IOCTL(OTHERVP(ap->a_vp), ap->a_command, ap->a_data, + ap->a_fflag, ap->a_cred, ap->a_p)); +} + +int +union_select(ap) + struct vop_select_args /* { + struct vnode *a_vp; + int a_which; + int a_fflags; + struct ucred *a_cred; + struct proc *a_p; + } */ *ap; +{ + + return (VOP_SELECT(OTHERVP(ap->a_vp), ap->a_which, ap->a_fflags, + ap->a_cred, ap->a_p)); +} + +int +union_mmap(ap) + struct vop_mmap_args /* { + struct vnode *a_vp; + int a_fflags; + struct ucred *a_cred; + struct proc *a_p; + } */ *ap; +{ + + return (VOP_MMAP(OTHERVP(ap->a_vp), ap->a_fflags, + ap->a_cred, ap->a_p)); +} + +int +union_fsync(ap) + struct vop_fsync_args /* { + struct vnode *a_vp; + struct ucred *a_cred; + int a_waitfor; + struct proc *a_p; + } */ *ap; +{ + int error = 0; + struct vnode *targetvp = OTHERVP(ap->a_vp); + + if (targetvp) { + int dolock = (targetvp == LOWERVP(ap->a_vp)); + + if (dolock) + VOP_LOCK(targetvp); + else + FIXUP(VTOUNION(ap->a_vp)); + error = VOP_FSYNC(targetvp, ap->a_cred, + ap->a_waitfor, ap->a_p); + if (dolock) + VOP_UNLOCK(targetvp); + } + + return (error); +} + +int +union_seek(ap) + struct vop_seek_args /* { + struct vnode *a_vp; + off_t a_oldoff; + off_t a_newoff; + struct ucred *a_cred; + } */ *ap; +{ + + return (VOP_SEEK(OTHERVP(ap->a_vp), ap->a_oldoff, ap->a_newoff, ap->a_cred)); +} + +int +union_remove(ap) + struct vop_remove_args /* { + struct vnode *a_dvp; + struct vnode *a_vp; + struct componentname *a_cnp; + } */ *ap; +{ + int error; + struct union_node *dun = VTOUNION(ap->a_dvp); + struct union_node *un = VTOUNION(ap->a_vp); + + if (dun->un_uppervp && un->un_uppervp) { + 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); + + error = VOP_REMOVE(dvp, vp, ap->a_cnp); + if (!error) + union_removed_upper(un); + + /* + * XXX: should create a whiteout here + */ + } else { + /* + * XXX: should create a whiteout here + */ + vput(ap->a_dvp); + vput(ap->a_vp); + error = EROFS; + } + + return (error); +} + +int +union_link(ap) + struct vop_link_args /* { + struct vnode *a_vp; + struct vnode *a_tdvp; + struct componentname *a_cnp; + } */ *ap; +{ + int error; + struct union_node *dun = VTOUNION(ap->a_vp); + struct union_node *un = VTOUNION(ap->a_tdvp); + + if (dun->un_uppervp && un->un_uppervp) { + struct vnode *dvp = dun->un_uppervp; + struct vnode *vp = un->un_uppervp; + + FIXUP(dun); + VREF(dvp); + dun->un_flags |= UN_KLOCK; + vput(ap->a_vp); + FIXUP(un); + VREF(vp); + vrele(ap->a_tdvp); + + error = VOP_LINK(dvp, vp, ap->a_cnp); + } else { + /* + * XXX: need to copy to upper layer + * and do the link there. + */ + vput(ap->a_vp); + vrele(ap->a_tdvp); + error = EROFS; + } + + return (error); +} + +int +union_rename(ap) + struct vop_rename_args /* { + struct vnode *a_fdvp; + struct vnode *a_fvp; + struct componentname *a_fcnp; + struct vnode *a_tdvp; + struct vnode *a_tvp; + struct componentname *a_tcnp; + } */ *ap; +{ + int error; + + struct vnode *fdvp = ap->a_fdvp; + struct vnode *fvp = ap->a_fvp; + struct vnode *tdvp = ap->a_tdvp; + struct vnode *tvp = ap->a_tvp; + + if (fdvp->v_op == union_vnodeop_p) { /* always true */ + struct union_node *un = VTOUNION(fdvp); + if (un->un_uppervp == NULLVP) { + error = EROFS; + goto bad; + } + + FIXUP(un); + fdvp = un->un_uppervp; + VREF(fdvp); + vrele(ap->a_fdvp); + } + + if (fvp->v_op == union_vnodeop_p) { /* always true */ + struct union_node *un = VTOUNION(fvp); + if (un->un_uppervp == NULLVP) { + error = EROFS; + goto bad; + } + + FIXUP(un); + fvp = un->un_uppervp; + VREF(fvp); + vrele(ap->a_fvp); + } + + if (tdvp->v_op == union_vnodeop_p) { + struct union_node *un = VTOUNION(tdvp); + if (un->un_uppervp == NULLVP) { + error = EROFS; + goto bad; + } + + tdvp = un->un_uppervp; + VREF(tdvp); + un->un_flags |= UN_KLOCK; + vput(ap->a_tdvp); + } + + if (tvp && tvp->v_op == union_vnodeop_p) { + struct union_node *un = VTOUNION(tvp); + if (un->un_uppervp == NULLVP) { + error = EROFS; + goto bad; + } + + tvp = un->un_uppervp; + VREF(tvp); + un->un_flags |= UN_KLOCK; + vput(ap->a_tvp); + } + + return (VOP_RENAME(fdvp, fvp, ap->a_fcnp, tdvp, tvp, ap->a_tcnp)); + +bad: + vrele(fdvp); + vrele(fvp); + vput(tdvp); + if (tvp) + vput(tvp); + + return (error); +} + +int +union_mkdir(ap) + struct vop_mkdir_args /* { + struct vnode *a_dvp; + struct vnode **a_vpp; + struct componentname *a_cnp; + struct vattr *a_vap; + } */ *ap; +{ + struct union_node *un = VTOUNION(ap->a_dvp); + struct vnode *dvp = un->un_uppervp; + + if (dvp) { + int error; + struct vnode *vp; + + FIXUP(un); + VREF(dvp); + un->un_flags |= UN_KLOCK; + vput(ap->a_dvp); + error = VOP_MKDIR(dvp, &vp, ap->a_cnp, ap->a_vap); + if (error) + return (error); + + error = union_allocvp( + ap->a_vpp, + ap->a_dvp->v_mount, + ap->a_dvp, + NULLVP, + ap->a_cnp, + vp, + NULLVP); + if (error) + vput(vp); + return (error); + } + + vput(ap->a_dvp); + return (EROFS); +} + +int +union_rmdir(ap) + struct vop_rmdir_args /* { + struct vnode *a_dvp; + struct vnode *a_vp; + struct componentname *a_cnp; + } */ *ap; +{ + int error; + struct union_node *dun = VTOUNION(ap->a_dvp); + struct union_node *un = VTOUNION(ap->a_vp); + + if (dun->un_uppervp && un->un_uppervp) { + 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); + + error = VOP_RMDIR(dvp, vp, ap->a_cnp); + if (!error) + union_removed_upper(un); + + /* + * XXX: should create a whiteout here + */ + } else { + /* + * XXX: should create a whiteout here + */ + vput(ap->a_dvp); + vput(ap->a_vp); + error = EROFS; + } + + return (error); +} + +int +union_symlink(ap) + struct vop_symlink_args /* { + struct vnode *a_dvp; + struct vnode **a_vpp; + struct componentname *a_cnp; + struct vattr *a_vap; + char *a_target; + } */ *ap; +{ + struct union_node *un = VTOUNION(ap->a_dvp); + struct vnode *dvp = un->un_uppervp; + + if (dvp) { + int error; + struct vnode *vp; + struct mount *mp = ap->a_dvp->v_mount; + + FIXUP(un); + VREF(dvp); + un->un_flags |= UN_KLOCK; + vput(ap->a_dvp); + error = VOP_SYMLINK(dvp, &vp, ap->a_cnp, + ap->a_vap, ap->a_target); + *ap->a_vpp = NULLVP; + return (error); + } + + vput(ap->a_dvp); + return (EROFS); +} + +/* + * union_readdir works in concert with getdirentries and + * readdir(3) to provide a list of entries in the unioned + * directories. getdirentries is responsible for walking + * down the union stack. readdir(3) is responsible for + * eliminating duplicate names from the returned data stream. + */ +int +union_readdir(ap) + struct vop_readdir_args /* { + struct vnodeop_desc *a_desc; + struct vnode *a_vp; + struct uio *a_uio; + struct ucred *a_cred; + } */ *ap; +{ + int error = 0; + struct union_node *un = VTOUNION(ap->a_vp); + + if (un->un_uppervp) { + FIXUP(un); + error = VOP_READDIR(un->un_uppervp, ap->a_uio, ap->a_cred); + } + + return (error); +} + +int +union_readlink(ap) + struct vop_readlink_args /* { + struct vnode *a_vp; + struct uio *a_uio; + struct ucred *a_cred; + } */ *ap; +{ + int error; + struct vnode *vp = OTHERVP(ap->a_vp); + int dolock = (vp == LOWERVP(ap->a_vp)); + + if (dolock) + VOP_LOCK(vp); + else + FIXUP(VTOUNION(ap->a_vp)); + error = VOP_READLINK(vp, ap->a_uio, ap->a_cred); + if (dolock) + VOP_UNLOCK(vp); + + return (error); +} + +int +union_abortop(ap) + struct vop_abortop_args /* { + struct vnode *a_dvp; + struct componentname *a_cnp; + } */ *ap; +{ + int error; + struct vnode *vp = OTHERVP(ap->a_dvp); + struct union_node *un = VTOUNION(ap->a_dvp); + int islocked = un->un_flags & UN_LOCKED; + int dolock = (vp == LOWERVP(ap->a_dvp)); + + if (islocked) { + if (dolock) + VOP_LOCK(vp); + else + FIXUP(VTOUNION(ap->a_dvp)); + } + error = VOP_ABORTOP(vp, ap->a_cnp); + if (islocked && dolock) + VOP_UNLOCK(vp); + + return (error); +} + +int +union_inactive(ap) + struct vop_inactive_args /* { + struct vnode *a_vp; + } */ *ap; +{ + + /* + * Do nothing (and _don't_ bypass). + * Wait to vrele lowervp until reclaim, + * so that until then our union_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. + */ + +#ifdef UNION_DIAGNOSTIC + struct union_node *un = VTOUNION(ap->a_vp); + + if (un->un_flags & UN_LOCKED) + panic("union: inactivating locked node"); +#endif + + return (0); +} + +int +union_reclaim(ap) + struct vop_reclaim_args /* { + struct vnode *a_vp; + } */ *ap; +{ + + union_freevp(ap->a_vp); + + return (0); +} + +int +union_lock(ap) + struct vop_lock_args *ap; +{ + struct vnode *vp = ap->a_vp; + struct union_node *un; + +start: + while (vp->v_flag & VXLOCK) { + vp->v_flag |= VXWANT; + sleep((caddr_t)vp, PINOD); + } + + un = VTOUNION(vp); + + if (un->un_uppervp) { + if ((un->un_flags & UN_ULOCK) == 0) { + un->un_flags |= UN_ULOCK; + VOP_LOCK(un->un_uppervp); + } +#ifdef DIAGNOSTIC + if (un->un_flags & UN_KLOCK) + panic("union: dangling upper lock"); +#endif + } + + if (un->un_flags & UN_LOCKED) { +#ifdef DIAGNOSTIC + if (curproc && un->un_pid == curproc->p_pid && + un->un_pid > -1 && curproc->p_pid > -1) + panic("union: locking against myself"); +#endif + un->un_flags |= UN_WANT; + sleep((caddr_t) &un->un_flags, PINOD); + goto start; + } + +#ifdef DIAGNOSTIC + if (curproc) + un->un_pid = curproc->p_pid; + else + un->un_pid = -1; +#endif + + un->un_flags |= UN_LOCKED; + return (0); +} + +int +union_unlock(ap) + struct vop_lock_args *ap; +{ + struct union_node *un = VTOUNION(ap->a_vp); + +#ifdef DIAGNOSTIC + if ((un->un_flags & UN_LOCKED) == 0) + panic("union: unlock unlocked node"); + if (curproc && un->un_pid != curproc->p_pid && + curproc->p_pid > -1 && un->un_pid > -1) + panic("union: unlocking other process's union node"); +#endif + + 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_WANT) { + un->un_flags &= ~UN_WANT; + wakeup((caddr_t) &un->un_flags); + } + +#ifdef DIAGNOSTIC + un->un_pid = 0; +#endif + + return (0); +} + +int +union_bmap(ap) + struct vop_bmap_args /* { + struct vnode *a_vp; + daddr_t a_bn; + struct vnode **a_vpp; + daddr_t *a_bnp; + int *a_runp; + } */ *ap; +{ + int error; + struct vnode *vp = OTHERVP(ap->a_vp); + int dolock = (vp == LOWERVP(ap->a_vp)); + + if (dolock) + VOP_LOCK(vp); + else + FIXUP(VTOUNION(ap->a_vp)); + error = VOP_BMAP(vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp); + if (dolock) + VOP_UNLOCK(vp); + + return (error); +} + +int +union_print(ap) + struct vop_print_args /* { + struct vnode *a_vp; + } */ *ap; +{ + struct vnode *vp = ap->a_vp; + + printf("\ttag VT_UNION, vp=%x, uppervp=%x, lowervp=%x\n", + vp, UPPERVP(vp), LOWERVP(vp)); + return (0); +} + +int +union_islocked(ap) + struct vop_islocked_args /* { + struct vnode *a_vp; + } */ *ap; +{ + + return ((VTOUNION(ap->a_vp)->un_flags & UN_LOCKED) ? 1 : 0); +} + +int +union_pathconf(ap) + struct vop_pathconf_args /* { + struct vnode *a_vp; + int a_name; + int *a_retval; + } */ *ap; +{ + int error; + struct vnode *vp = OTHERVP(ap->a_vp); + int dolock = (vp == LOWERVP(ap->a_vp)); + + if (dolock) + VOP_LOCK(vp); + else + FIXUP(VTOUNION(ap->a_vp)); + error = VOP_PATHCONF(vp, ap->a_name, ap->a_retval); + if (dolock) + VOP_UNLOCK(vp); + + return (error); +} + +int +union_advlock(ap) + struct vop_advlock_args /* { + struct vnode *a_vp; + caddr_t a_id; + int a_op; + struct flock *a_fl; + int a_flags; + } */ *ap; +{ + + return (VOP_ADVLOCK(OTHERVP(ap->a_vp), ap->a_id, ap->a_op, + ap->a_fl, ap->a_flags)); +} + + +/* + * 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 +union_strategy(ap) + struct vop_strategy_args /* { + struct buf *a_bp; + } */ *ap; +{ + struct buf *bp = ap->a_bp; + int error; + struct vnode *savedvp; + + savedvp = bp->b_vp; + bp->b_vp = OTHERVP(bp->b_vp); + +#ifdef DIAGNOSTIC + if (bp->b_vp == NULLVP) + panic("union_strategy: nil vp"); + if (((bp->b_flags & B_READ) == 0) && + (bp->b_vp == LOWERVP(savedvp))) + panic("union_strategy: writing to lowervp"); +#endif + + error = VOP_STRATEGY(bp); + bp->b_vp = savedvp; + + return (error); +} + +/* + * Global vfs data structures + */ +int (**union_vnodeop_p)(); +struct vnodeopv_entry_desc union_vnodeop_entries[] = { + { &vop_default_desc, vn_default_error }, + { &vop_lookup_desc, union_lookup }, /* lookup */ + { &vop_create_desc, union_create }, /* create */ + { &vop_mknod_desc, union_mknod }, /* mknod */ + { &vop_open_desc, union_open }, /* open */ + { &vop_close_desc, union_close }, /* close */ + { &vop_access_desc, union_access }, /* access */ + { &vop_getattr_desc, union_getattr }, /* getattr */ + { &vop_setattr_desc, union_setattr }, /* setattr */ + { &vop_read_desc, union_read }, /* read */ + { &vop_write_desc, union_write }, /* write */ + { &vop_ioctl_desc, union_ioctl }, /* ioctl */ + { &vop_select_desc, union_select }, /* select */ + { &vop_mmap_desc, union_mmap }, /* mmap */ + { &vop_fsync_desc, union_fsync }, /* fsync */ + { &vop_seek_desc, union_seek }, /* seek */ + { &vop_remove_desc, union_remove }, /* remove */ + { &vop_link_desc, union_link }, /* link */ + { &vop_rename_desc, union_rename }, /* rename */ + { &vop_mkdir_desc, union_mkdir }, /* mkdir */ + { &vop_rmdir_desc, union_rmdir }, /* rmdir */ + { &vop_symlink_desc, union_symlink }, /* symlink */ + { &vop_readdir_desc, union_readdir }, /* readdir */ + { &vop_readlink_desc, union_readlink }, /* readlink */ + { &vop_abortop_desc, union_abortop }, /* abortop */ + { &vop_inactive_desc, union_inactive }, /* inactive */ + { &vop_reclaim_desc, union_reclaim }, /* reclaim */ + { &vop_lock_desc, union_lock }, /* lock */ + { &vop_unlock_desc, union_unlock }, /* unlock */ + { &vop_bmap_desc, union_bmap }, /* bmap */ + { &vop_strategy_desc, union_strategy }, /* strategy */ + { &vop_print_desc, union_print }, /* print */ + { &vop_islocked_desc, union_islocked }, /* islocked */ + { &vop_pathconf_desc, union_pathconf }, /* pathconf */ + { &vop_advlock_desc, union_advlock }, /* advlock */ +#ifdef notdef + { &vop_blkatoff_desc, union_blkatoff }, /* blkatoff */ + { &vop_valloc_desc, union_valloc }, /* valloc */ + { &vop_vfree_desc, union_vfree }, /* vfree */ + { &vop_truncate_desc, union_truncate }, /* truncate */ + { &vop_update_desc, union_update }, /* update */ + { &vop_bwrite_desc, union_bwrite }, /* bwrite */ +#endif + { (struct vnodeop_desc*)NULL, (int(*)())NULL } +}; +struct vnodeopv_desc union_vnodeop_opv_desc = + { &union_vnodeop_p, union_vnodeop_entries }; |
