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[src/trunk]: src/sys/kern Housecleaning time:



details:   https://anonhg.NetBSD.org/src/rev/3e086a8dcfc0
branches:  trunk
changeset: 474378:3e086a8dcfc0
user:      sommerfeld <sommerfeld%NetBSD.org@localhost>
date:      Sun Jul 04 20:16:57 1999 +0000

description:
Housecleaning time:

Fix and document naming convention for vnode variables (always use
lvp/lvpp and uvp/uvpp instead of a hash of cvp, vpp, dvpp, pvp, pvpp).

Delete old stale #if 0'ed code at the end.

Change error path code in getcwd_getcache() slightly (merge common
cleanup code; shouldn't affect behavior any).

diffstat:

 sys/kern/vfs_getcwd.c |  371 +++++++++++++++++--------------------------------
 1 files changed, 130 insertions(+), 241 deletions(-)

diffs (truncated from 602 to 300 lines):

diff -r 3a091bd4e930 -r 3e086a8dcfc0 sys/kern/vfs_getcwd.c
--- a/sys/kern/vfs_getcwd.c     Sun Jul 04 20:07:51 1999 +0000
+++ b/sys/kern/vfs_getcwd.c     Sun Jul 04 20:16:57 1999 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: vfs_getcwd.c,v 1.8 1999/06/21 05:11:09 sommerfeld Exp $ */
+/* $NetBSD: vfs_getcwd.c,v 1.9 1999/07/04 20:16:57 sommerfeld Exp $ */
 
 /*-
  * Copyright (c) 1999 The NetBSD Foundation, Inc.
@@ -68,25 +68,44 @@
 #define DIRENT_MINSIZE (sizeof(struct dirent) - (MAXNAMLEN+1) + 4)
 
 /*
+ * Vnode variable naming conventions in this file:
+ *
+ * rvp: the current root we're aiming towards.
+ * lvp, *lvpp: the "lower" vnode
+ * uvp, *uvpp: the "upper" vnode.
+ *
+ * Since all the vnodes we're dealing with are directories, and the
+ * lookups are going *up* in the filesystem rather than *down*, the
+ * usual "pvp" (parent) or "dvp" (directory) naming conventions are
+ * too confusing.
+ */
+
+/*
  * XXX Will infinite loop in certain cases if a directory read reliably
  *     returns EINVAL on last block.
  * XXX is EINVAL the right thing to return if a directory is malformed?
  */
 
 /*
- * Find parent vnode of cvp, return in *pvpp
- * Scan it looking for name of directory entry pointing at cvp.
+ * XXX Untested vs. mount -o union; probably does the wrong thing.
+ */
+
+/*
+ * Find parent vnode of *lvpp, return in *uvpp
+ *
+ * If we care about the name, scan it looking for name of directory
+ * entry pointing at lvp.
  *
  * Place the name in the buffer which starts at bufp, immediately
  * before *bpp, and move bpp backwards to point at the start of it.
  *
- * On entry, *cvpp is a locked vnode reference; on exit, it is vput and NULL'ed
- * On exit, *pvpp is either NULL or is a locked vnode reference.
+ * On entry, *lvpp is a locked vnode reference; on exit, it is vput and NULL'ed
+ * On exit, *uvpp is either NULL or is a locked vnode reference.
  */
 static int
-getcwd_scandir(cvpp, pvpp, bpp, bufp, p)
-       struct vnode **cvpp;
-       struct vnode **pvpp;
+getcwd_scandir(lvpp, uvpp, bpp, bufp, p)
+       struct vnode **lvpp;
+       struct vnode **uvpp;
        char **bpp;
        char *bufp;
        struct proc *p;
@@ -101,8 +120,8 @@
        int     dirbuflen;
        ino_t   fileno;
        struct vattr va;
-       struct vnode *pvp = NULL;
-       struct vnode *cvp = *cvpp;      
+       struct vnode *uvp = NULL;
+       struct vnode *lvp = *lvpp;      
        struct componentname cn;
        int len, reclen;
        tries = 0;
@@ -112,11 +131,11 @@
         * current directory is still locked.
         */
        if (bufp != NULL) {
-               error = VOP_GETATTR(cvp, &va, p->p_ucred, p);
+               error = VOP_GETATTR(lvp, &va, p->p_ucred, p);
                if (error) {
-                       vput(cvp);
-                       *cvpp = NULL;
-                       *pvpp = NULL;
+                       vput(lvp);
+                       *lvpp = NULL;
+                       *uvpp = NULL;
                        return error;
                }
        }
@@ -136,22 +155,22 @@
        cn.cn_consume = 0;
        
        /*
-        * At this point, cvp is locked and will be unlocked by the lookup.
-        * On successful return, *pvpp will be locked
+        * At this point, lvp is locked and will be unlocked by the lookup.
+        * On successful return, *uvpp will be locked
         */
-       error = VOP_LOOKUP(cvp, pvpp, &cn);
+       error = VOP_LOOKUP(lvp, uvpp, &cn);
        if (error) {
-               vput(cvp);
-               *cvpp = NULL;
-               *pvpp = NULL;
+               vput(lvp);
+               *lvpp = NULL;
+               *uvpp = NULL;
                return error;
        }
-       pvp = *pvpp;
+       uvp = *uvpp;
 
        /* If we don't care about the pathname, we're done */
        if (bufp == NULL) {
-               vrele(cvp);
-               *cvpp = NULL;
+               vrele(lvp);
+               *lvpp = NULL;
                return 0;
        }
        
@@ -181,7 +200,7 @@
 
                eofflag = 0;
 
-               error = VOP_READDIR(pvp, &uio, p->p_ucred, &eofflag, 0, 0);
+               error = VOP_READDIR(uvp, &uio, p->p_ucred, &eofflag, 0, 0);
 
                off = uio.uio_offset;
 
@@ -243,17 +262,17 @@
         * Deal with mount -o union, which unions only the
         * root directory of the mount.
         */
-       if ((pvp->v_flag & VROOT) &&
-           (pvp->v_mount->mnt_flag & MNT_UNION)) {
-               struct vnode *tvp = pvp;
-               pvp = pvp->v_mount->mnt_vnodecovered;
+       if ((uvp->v_flag & VROOT) &&
+           (uvp->v_mount->mnt_flag & MNT_UNION)) {
+               struct vnode *tvp = uvp;
+               uvp = uvp->v_mount->mnt_vnodecovered;
                vput(tvp);
-               VREF(pvp);
-               *pvpp = pvp;
-               error = vn_lock(pvp, LK_EXCLUSIVE | LK_RETRY);
+               VREF(uvp);
+               *uvpp = uvp;
+               error = vn_lock(uvp, LK_EXCLUSIVE | LK_RETRY);
                if (error != 0) {
-                       vrele(pvp);
-                       *pvpp = pvp = NULL;
+                       vrele(uvp);
+                       *uvpp = uvp = NULL;
                        goto out;
                }
                goto unionread;
@@ -262,8 +281,8 @@
        error = ENOENT;
                
 out:
-       vrele(cvp);
-       *cvpp = NULL;
+       vrele(lvp);
+       *lvpp = NULL;
        free(dirbuf, M_TEMP);
        return error;
 }
@@ -274,69 +293,75 @@
  *
  * XXX vget failure path is untested.
  *
- * On entry, *vpp is a locked vnode reference.
+ * On entry, *lvpp is a locked vnode reference.
  * On exit, one of the following is the case:
- *     0) Both *vpp and *vpp are NULL and failure is returned.
- *     1) *dvpp is NULL, *vpp remains locked and -1 is returned (cache miss)
- *      2) *dvpp is a locked vnode reference, *vpp is vput and NULL'ed
+ *     0) Both *lvpp and *uvpp are NULL and failure is returned.
+ *     1) *uvpp is NULL, *lvpp remains locked and -1 is returned (cache miss)
+ *      2) *uvpp is a locked vnode reference, *lvpp is vput and NULL'ed
  *        and 0 is returned (cache hit)
  */
 
 static int
-getcwd_getcache(vpp, dvpp, bpp, bufp)
-       struct vnode **vpp, **dvpp;
+getcwd_getcache(lvpp, uvpp, bpp, bufp)
+       struct vnode **lvpp, **uvpp;
        char **bpp;
        char *bufp;
 {
-       struct vnode *cvp, *pvp = NULL;
+       struct vnode *lvp, *uvp = NULL;
        int error;
        int vpid;
        
-       cvp = *vpp;
+       lvp = *lvpp;
        
        /*
         * This returns 0 on a cache hit, -1 on a clean cache miss,
         * or an errno on other failure.
         */
-       error = cache_revlookup(cvp, dvpp, bpp, bufp);
+       error = cache_revlookup(lvp, uvpp, bpp, bufp);
        if (error) {
                if (error != -1) {
-                       vput(cvp);
-                       *vpp = NULL;
-                       *dvpp = NULL;
+                       vput(lvp);
+                       *lvpp = NULL;
+                       *uvpp = NULL;
                }
                return error;
        }
-       pvp = *dvpp;
-       vpid = pvp->v_id;
+       uvp = *uvpp;
+       vpid = uvp->v_id;
 
        /*
         * Since we're going up, we have to release the current lock
         * before we take the parent lock.
         */
 
-       VOP_UNLOCK(cvp, 0);
+       VOP_UNLOCK(lvp, 0);
 
-       error = vget(pvp, LK_EXCLUSIVE | LK_RETRY);
+       error = vget(uvp, LK_EXCLUSIVE | LK_RETRY);
        if (error != 0)
-               *dvpp = NULL;
+               *uvpp = NULL;
        /*
-        * Check that vnode capability didn't change while we were waiting
-        * for the lock.
+        * Verify that vget succeeded, and check that vnode capability
+        * didn't change while we were waiting for the lock.
         */
-       if (error || (vpid != pvp->v_id)) {
+       if (error || (vpid != uvp->v_id)) {
                /*
-                * oops, it did.  do this the hard way.
+                * Oops, we missed.  If the vget failed, or the
+                * capability changed, try to get our lock back; if
+                * that works, tell caller to try things the hard way,
+                * otherwise give up.
                 */
-               if (!error) vput(pvp);
-               error = vn_lock(cvp, LK_EXCLUSIVE | LK_RETRY);          
-               *dvpp = NULL;
-               return -1;
+               if (!error) vput(uvp);
+               *uvpp = NULL;
+               
+               error = vn_lock(lvp, LK_EXCLUSIVE | LK_RETRY);
+
+               if (!error)
+                       return -1;
        }
-       vrele(cvp);
-       *vpp = NULL;
+       vrele(lvp);
+       *lvpp = NULL;
 
-       return 0;
+       return error;
 }
 
 /*
@@ -345,8 +370,8 @@
 
 #define GETCWD_CHECK_ACCESS 0x0001
 
-static int getcwd_common (dvp, rvp, bpp, bufp, limit, flags, p)
-       struct vnode *dvp;
+static int getcwd_common (lvp, rvp, bpp, bufp, limit, flags, p)
+       struct vnode *lvp;
        struct vnode *rvp;
        char **bpp;
        char *bufp;
@@ -355,7 +380,7 @@
        struct proc *p;
 {
        struct cwdinfo *cwdi = p->p_cwdi;
-       struct vnode *pvp = NULL;
+       struct vnode *uvp = NULL;
        char *bp = NULL;
        int error;
        
@@ -366,19 +391,19 @@
        }
        
        VREF(rvp);
-       VREF(dvp);
+       VREF(lvp);
 
        /*
         * Error handling invariant:



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