/*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2016 Apple Inc. All rights reserved.
*
* @APPLE_LICENSE_HEADER_START@
- *
+ *
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this
* file.
- *
+ *
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
- *
+ *
* @APPLE_LICENSE_HEADER_END@
*/
-/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
-/*
- * Copyright (c) 1992, 1993
- * The Regents of the University of California. All rights reserved.
+
+/*-
+ * Portions Copyright (c) 1992, 1993
+ * The Regents of the University of California. All rights reserved.
*
* This code is derived from software donated to Berkeley by
* Jan-Simon Pendry.
* 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.
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
- * @(#)null_subr.c 8.7 (Berkeley) 5/14/95
+ * @(#)null_subr.c 8.7 (Berkeley) 5/14/95
*
- * null_subr.c 8.4 (Berkeley) 1/21/94
+ * $FreeBSD$
*/
-
#include <sys/param.h>
#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/malloc.h>
+#include <sys/mount.h>
#include <sys/proc.h>
-#include <sys/time.h>
-#include <sys/types.h>
#include <sys/vnode.h>
-#include <sys/mount_internal.h>
-#include <sys/namei.h>
-#include <sys/malloc.h>
-#include <sys/ubc.h>
-#include <miscfs/nullfs/null.h>
-#define LOG2_SIZEVNODE 7 /* log2(sizeof struct vnode) */
-#define NNULLNODECACHE 16
+#include "nullfs.h"
/*
* Null layer cache:
* Each cache entry holds a reference to the lower vnode
* along with a pointer to the alias vnode. When an
- * entry is added the lower vnode is vnode_get'd. When the
- * alias is removed the lower vnode is vnode_put'd.
+ * entry is added the lower vnode is VREF'd. When the
+ * alias is removed the lower vnode is vrele'd.
*/
-#define NULL_NHASH(vp) \
- (&null_node_hashtbl[(((u_long)vp)>>LOG2_SIZEVNODE) & null_node_hash])
-LIST_HEAD(null_node_hashhead, null_node) *null_node_hashtbl;
-u_long null_node_hash;
+#define NULL_HASH_SIZE (desiredvnodes / 10)
+
+/* osx doesn't really have the functionality freebsd uses here..gonna try this
+ * hacked hash...*/
+#define NULL_NHASH(vp) (&null_node_hashtbl[((((uintptr_t)vp) >> vnsz2log) + (uintptr_t)vnode_mount(vp)) & null_hash_mask])
+
+static LIST_HEAD(null_node_hashhead, null_node) * null_node_hashtbl;
+static lck_mtx_t null_hashmtx;
+static lck_attr_t * null_hashlck_attr;
+static lck_grp_t * null_hashlck_grp;
+static lck_grp_attr_t * null_hashlck_grp_attr;
+static u_long null_hash_mask;
+
+/* os x doesn't have hashes built into vnode. gonna try doing what freebsd does
+ anyway
+ Don't want to create a dependency on vnode_internal.h and the real struct
+ vnode.
+ 9 is an eyeball of the log 2 size of vnode */
+static int vnsz2log = 9;
+
+static int null_hashins(struct mount *, struct null_node *, struct vnode **);
+
+int
+nullfs_init_lck(lck_mtx_t * lck)
+{
+ int error = 1;
+ if (lck && null_hashlck_grp && null_hashlck_attr) {
+ lck_mtx_init(lck, null_hashlck_grp, null_hashlck_attr);
+ error = 0;
+ }
+ return error;
+}
+
+int
+nullfs_destroy_lck(lck_mtx_t * lck)
+{
+ int error = 1;
+ if (lck && null_hashlck_grp) {
+ lck_mtx_destroy(lck, null_hashlck_grp);
+ error = 0;
+ }
+ return error;
+}
/*
* Initialise cache headers
*/
-nullfs_init()
+int
+nullfs_init(__unused struct vfsconf * vfsp)
{
+ NULLFSDEBUG("%s\n", __FUNCTION__);
-#ifdef NULLFS_DIAGNOSTIC
- printf("nullfs_init\n"); /* printed during system boot */
-#endif
- null_node_hashtbl = hashinit(NNULLNODECACHE, M_CACHE, &null_node_hash);
+ /* assuming for now that this happens immediately and by default after fs
+ * installation */
+ null_hashlck_grp_attr = lck_grp_attr_alloc_init();
+ if (null_hashlck_grp_attr == NULL) {
+ goto error;
+ }
+ null_hashlck_grp = lck_grp_alloc_init("com.apple.filesystems.nullfs", null_hashlck_grp_attr);
+ if (null_hashlck_grp == NULL) {
+ goto error;
+ }
+ null_hashlck_attr = lck_attr_alloc_init();
+ if (null_hashlck_attr == NULL) {
+ goto error;
+ }
+
+ lck_mtx_init(&null_hashmtx, null_hashlck_grp, null_hashlck_attr);
+ null_node_hashtbl = hashinit(NULL_HASH_SIZE, M_TEMP, &null_hash_mask);
+ NULLFSDEBUG("%s finished\n", __FUNCTION__);
+ return (0);
+error:
+ printf("NULLFS: failed to get lock element\n");
+ if (null_hashlck_grp_attr) {
+ lck_grp_attr_free(null_hashlck_grp_attr);
+ null_hashlck_grp_attr = NULL;
+ }
+ if (null_hashlck_grp) {
+ lck_grp_free(null_hashlck_grp);
+ null_hashlck_grp = NULL;
+ }
+ if (null_hashlck_attr) {
+ lck_attr_free(null_hashlck_attr);
+ null_hashlck_attr = NULL;
+ }
+ return KERN_FAILURE;
+}
+
+int
+nullfs_uninit()
+{
+ /* This gets called when the fs is uninstalled, there wasn't an exact
+ * equivalent in vfsops */
+ lck_mtx_destroy(&null_hashmtx, null_hashlck_grp);
+ FREE(null_node_hashtbl, M_TEMP);
+ if (null_hashlck_grp_attr) {
+ lck_grp_attr_free(null_hashlck_grp_attr);
+ null_hashlck_grp_attr = NULL;
+ }
+ if (null_hashlck_grp) {
+ lck_grp_free(null_hashlck_grp);
+ null_hashlck_grp = NULL;
+ }
+ if (null_hashlck_attr) {
+ lck_attr_free(null_hashlck_attr);
+ null_hashlck_attr = NULL;
+ }
+ return (0);
}
/*
- * Return a vnode_get'ed alias for lower vnode if already exists, else 0.
+ * Find the nullfs vnode mapped to lowervp. Return it in *vpp with an iocount if found.
+ * Return 0 on success. On failure *vpp will be null and a non-zero error code will be returned.
*/
-static struct vnode *
-null_node_find(mp, lowervp)
- struct mount *mp;
- struct vnode *lowervp;
+int
+null_hashget(struct mount * mp, struct vnode * lowervp, struct vnode ** vpp)
{
- struct proc *p = curproc; /* XXX */
- struct null_node_hashhead *hd;
- struct null_node *a;
- struct vnode *vp;
+ struct null_node_hashhead * hd;
+ struct null_node * a;
+ struct vnode * vp;
+ int error = ENOENT;
/*
* Find hash base, and then search the (two-way) linked
* list looking for a null_node structure which is referencing
- * the lower vnode. If found, the increment the null_node
- * reference count (but NOT the lower vnode's vnode_get counter).
+ * the lower vnode. We only give up our reference at reclaim so
+ * just check whether the lowervp has gotten pulled from under us
*/
hd = NULL_NHASH(lowervp);
-loop:
- for (a = hd->lh_first; a != 0; a = a->null_hash.le_next) {
- if (a->null_lowervp == lowervp && NULLTOV(a)->v_mount == mp) {
+ lck_mtx_lock(&null_hashmtx);
+ LIST_FOREACH(a, hd, null_hash)
+ {
+ if (a->null_lowervp == lowervp && vnode_mount(NULLTOV(a)) == mp) {
vp = NULLTOV(a);
-
- if (vnode_get(vp)) {
- printf ("null_node_find: vget failed.\n");
- goto loop;
- };
- return (vp);
+ if (a->null_lowervid != vnode_vid(lowervp)) {
+ /*lowervp has reved */
+ error = EIO;
+ } else {
+ /* if we found something then get an iocount on it */
+ error = vnode_getwithvid(vp, a->null_myvid);
+ if (error == 0) {
+ *vpp = vp;
+ }
+ }
+ break;
}
}
-
- return NULL;
+ lck_mtx_unlock(&null_hashmtx);
+ return error;
}
-
/*
- * Make a new null_node node.
- * Vp is the alias vnode, lofsvp is the lower vnode.
- * Maintain a reference to (lowervp).
+ * Act like null_hashget, but add passed null_node to hash if no existing
+ * node found.
*/
static int
-null_node_alloc(mp, lowervp, vpp)
- struct mount *mp;
- struct vnode *lowervp;
- struct vnode **vpp;
+null_hashins(struct mount * mp, struct null_node * xp, struct vnode ** vpp)
{
- struct null_node_hashhead *hd;
- struct null_node *xp;
- struct vnode *othervp, *vp;
- int error;
+ struct null_node_hashhead * hd;
+ struct null_node * oxp;
+ struct vnode * ovp;
+ int error = 0;
- MALLOC(xp, struct null_node *, sizeof(struct null_node), M_TEMP, M_WAITOK);
- if (error = getnewvnode(VT_NULL, mp, null_vnodeop_p, vpp)) {
- FREE(xp, M_TEMP);
- return (error);
+ hd = NULL_NHASH(xp->null_lowervp);
+ lck_mtx_lock(&null_hashmtx);
+ LIST_FOREACH(oxp, hd, null_hash)
+ {
+ if (oxp->null_lowervp == xp->null_lowervp && vnode_mount(NULLTOV(oxp)) == mp) {
+ /*
+ * See null_hashget for a description of this
+ * operation.
+ */
+ ovp = NULLTOV(oxp);
+ if (oxp->null_lowervid != vnode_vid(oxp->null_lowervp)) {
+ /*vp doesn't exist so return null (not sure we are actually gonna catch
+ recycle right now
+ This is an exceptional case right now, it suggests the vnode we are
+ trying to add has been recycled
+ don't add it.*/
+ error = EIO;
+ goto end;
+ }
+ /* if we found something in the hash map then grab an iocount */
+ error = vnode_getwithvid(ovp, oxp->null_myvid);
+ if (error == 0) {
+ *vpp = ovp;
+ }
+ goto end;
+ }
}
- vp = *vpp;
-
- vp->v_type = lowervp->v_type;
- xp->null_vnode = vp;
- vp->v_data = xp;
- xp->null_lowervp = lowervp;
- /*
- * Before we insert our new node onto the hash chains,
- * check to see if someone else has beaten us to it.
- */
- if (othervp = null_node_find(lowervp)) {
- FREE(xp, M_TEMP);
- vp->v_type = VBAD; /* node is discarded */
- vp->v_usecount = 0; /* XXX */
- vp->v_data = 0; /* prevent access to freed data */
- *vpp = othervp;
- return 0;
- };
- if (vp->v_type == VREG)
- ubc_info_init(vp);
- vnode_get(lowervp); /* Extra vnode_get will be vnode_put'd in null_node_create */
- hd = NULL_NHASH(lowervp);
+ /* if it wasn't in the hash map then the vnode pointed to by xp already has a
+ * iocount so don't bother */
LIST_INSERT_HEAD(hd, xp, null_hash);
- return 0;
+ xp->null_flags |= NULL_FLAG_HASHED;
+end:
+ lck_mtx_unlock(&null_hashmtx);
+ return error;
}
-
/*
- * Try to find an existing null_node vnode refering
- * to it, otherwise make a new null_node vnode which
- * contains a reference to the lower vnode.
+ * Remove node from hash.
*/
-int
-null_node_create(mp, lowervp, newvpp)
- struct mount *mp;
- struct vnode *lowervp;
- struct vnode **newvpp;
+void
+null_hashrem(struct null_node * xp)
{
- struct vnode *aliasvp;
-
- if (aliasvp = null_node_find(mp, lowervp)) {
- /*
- * null_node_find has taken another reference
- * to the alias vnode.
- */
-#ifdef NULLFS_DIAGNOSTIC
- vprint("null_node_create: exists", NULLTOV(ap));
-#endif
- /* vnode_get(aliasvp); --- done in null_node_find */
- } else {
- int error;
-
- /*
- * Get new vnode.
- */
-#ifdef NULLFS_DIAGNOSTIC
- printf("null_node_create: create new alias vnode\n");
-#endif
-
- /*
- * Make new vnode reference the null_node.
- */
- if (error = null_node_alloc(mp, lowervp, &aliasvp))
- return error;
-
- /*
- * aliasvp is already vnode_get'd by getnewvnode()
- */
+ lck_mtx_lock(&null_hashmtx);
+ LIST_REMOVE(xp, null_hash);
+ lck_mtx_unlock(&null_hashmtx);
+}
+
+static struct null_node *
+null_nodecreate(struct vnode * lowervp)
+{
+ struct null_node * xp;
+
+ MALLOC(xp, struct null_node *, sizeof(struct null_node), M_TEMP, M_WAITOK | M_ZERO);
+ if (xp != NULL) {
+ if (lowervp) {
+ xp->null_lowervp = lowervp;
+ xp->null_lowervid = vnode_vid(lowervp);
+ }
}
+ return xp;
+}
- vnode_put(lowervp);
+/* assumption is that vnode has iocount on it after vnode create */
+int
+null_getnewvnode(
+ struct mount * mp, struct vnode * lowervp, struct vnode * dvp, struct vnode ** vpp, struct componentname * cnp, int root)
+{
+ struct vnode_fsparam vnfs_param;
+ int error = 0;
+ enum vtype type = VDIR;
+ struct null_node * xp = null_nodecreate(lowervp);
-#if DIAGNOSTIC
- if (lowervp->v_usecount < 1) {
- /* Should never happen... */
- vprint ("null_node_create: alias ", aliasvp);
- vprint ("null_node_create: lower ", lowervp);
- panic ("null_node_create: lower has 0 usecount.");
- };
-#endif
+ if (xp == NULL) {
+ return ENOMEM;
+ }
-#ifdef NULLFS_DIAGNOSTIC
- vprint("null_node_create: alias", aliasvp);
- vprint("null_node_create: lower", lowervp);
-#endif
+ if (lowervp) {
+ type = vnode_vtype(lowervp);
+ }
- *newvpp = aliasvp;
- return (0);
+ vnfs_param.vnfs_mp = mp;
+ vnfs_param.vnfs_vtype = type;
+ vnfs_param.vnfs_str = "nullfs";
+ vnfs_param.vnfs_dvp = dvp;
+ vnfs_param.vnfs_fsnode = (void *)xp;
+ vnfs_param.vnfs_vops = nullfs_vnodeop_p;
+ vnfs_param.vnfs_markroot = root;
+ vnfs_param.vnfs_marksystem = 0;
+ vnfs_param.vnfs_rdev = 0;
+ vnfs_param.vnfs_filesize = 0; // set this to 0 since we should only be shadowing non-regular files
+ vnfs_param.vnfs_cnp = cnp;
+ vnfs_param.vnfs_flags = VNFS_ADDFSREF;
+
+ error = vnode_create(VNCREATE_FLAVOR, VCREATESIZE, &vnfs_param, vpp);
+ if (error == 0) {
+ xp->null_vnode = *vpp;
+ xp->null_myvid = vnode_vid(*vpp);
+ vnode_settag(*vpp, VT_NULL);
+ } else {
+ FREE(xp, M_TEMP);
+ }
+ return error;
}
-#ifdef NULLFS_DIAGNOSTIC
-struct vnode *
-null_checkvp(vp, fil, lno)
- struct vnode *vp;
- char *fil;
- int lno;
+
+/*
+ * Make a new or get existing nullfs node.
+ * Vp is the alias vnode, lowervp is the lower vnode.
+ *
+ * lowervp is assumed to have an iocount on it from the caller
+ */
+int
+null_nodeget(
+ struct mount * mp, struct vnode * lowervp, struct vnode * dvp, struct vnode ** vpp, struct componentname * cnp, int root)
{
- struct null_node *a = VTONULL(vp);
-#ifdef notyet
+ struct vnode * vp;
+ int error;
+
+ /* Lookup the hash firstly. */
+ error = null_hashget(mp, lowervp, vpp);
+ /* ENOENT means it wasn't found, EIO is a failure we should bail from, 0 is it
+ * was found */
+ if (error != ENOENT) {
+ /* null_hashget checked the vid, so if we got something here its legit to
+ * the best of our knowledge*/
+ /* if we found something then there is an iocount on vpp,
+ if we didn't find something then vpp shouldn't be used by the caller */
+ return error;
+ }
+
/*
- * Can't do this check because vnop_reclaim runs
- * with a funny vop vector.
+ * We do not serialize vnode creation, instead we will check for
+ * duplicates later, when adding new vnode to hash.
*/
- if (vp->v_op != null_vnodeop_p) {
- printf ("null_checkvp: on non-null-node\n");
- while (null_checkvp_barrier) /*WAIT*/ ;
- panic("null_checkvp");
- };
-#endif
- if (a->null_lowervp == NULL) {
- /* Should never happen */
- int i; u_long *p;
- printf("vp = %x, ZERO ptr\n", vp);
- for (p = (u_long *) a, i = 0; i < 8; i++)
- printf(" %x", p[i]);
- printf("\n");
- /* wait for debugger */
- while (null_checkvp_barrier) /*WAIT*/ ;
- panic("null_checkvp");
+ error = vnode_ref(lowervp); // take a ref on lowervp so we let the system know we care about it
+ if(error)
+ {
+ // Failed to get a reference on the lower vp so bail. Lowervp may be gone already.
+ return error;
}
- if (a->null_lowervp->v_usecount < 1) {
- int i; u_long *p;
- printf("vp = %x, unref'ed lowervp\n", vp);
- for (p = (u_long *) a, i = 0; i < 8; i++)
- printf(" %x", p[i]);
- printf("\n");
- /* wait for debugger */
- while (null_checkvp_barrier) /*WAIT*/ ;
- panic ("null with unref'ed lowervp");
- };
-#ifdef notyet
- printf("null %x/%d -> %x/%d [%s, %d]\n",
- NULLTOV(a), NULLTOV(a)->v_usecount,
- a->null_lowervp, a->null_lowervp->v_usecount,
- fil, lno);
-#endif
- return a->null_lowervp;
+
+ error = null_getnewvnode(mp, lowervp, dvp, &vp, cnp, root);
+
+ if (error) {
+ vnode_rele(lowervp);
+ return (error);
+ }
+
+ /*
+ * Atomically insert our new node into the hash or vget existing
+ * if someone else has beaten us to it.
+ */
+ error = null_hashins(mp, VTONULL(vp), vpp);
+ if (error || *vpp != NULL) {
+ /* recycle will call reclaim which will get rid of the internals */
+ vnode_recycle(vp);
+ vnode_put(vp);
+ /* if we found vpp, then null_hashins put an iocount on it */
+ return error;
+ }
+
+ /* vp has an iocount from null_getnewvnode */
+ *vpp = vp;
+
+ return (0);
}
-#endif
projects / apple / xnu.git / blobdiff