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Date:      Sun, 19 Apr 2009 05:34:07 +0000 (UTC)
From:      Konstantin Belousov <kib@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r191260 - head/sys/ufs/ufs
Message-ID:  <200904190534.n3J5Y701099624@svn.freebsd.org>
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Author: kib
Date: Sun Apr 19 05:34:07 2009
New Revision: 191260
URL: http://svn.freebsd.org/changeset/base/191260

Log:
  When verifying '..' after VFS_VGET() in ufs_lookup(), do not return
  error if '..' is still there but changed between lookup and check.
  Start relookup instead. Rename is supposed to change '..' reference
  atomically, so transient failures introduced by r191137 are wrong.
  
  While rearranging the code to allow lookup restart in ufs_lookup(),
  remove the comment that only distracts the reader.
  
  Noted and reviewed by:	tegge
  Also reported by:	pho
  MFC after:	1 month

Modified:
  head/sys/ufs/ufs/ufs_lookup.c

Modified: head/sys/ufs/ufs/ufs_lookup.c
==============================================================================
--- head/sys/ufs/ufs/ufs_lookup.c	Sun Apr 19 04:44:05 2009	(r191259)
+++ head/sys/ufs/ufs/ufs_lookup.c	Sun Apr 19 05:34:07 2009	(r191260)
@@ -78,7 +78,7 @@ SYSCTL_INT(_debug, OID_AUTO, dircheck, C
 #define OFSFMT(vp)	((vp)->v_mount->mnt_maxsymlinklen <= 0)
 
 static int ufs_lookup_(struct vnode *, struct vnode **, struct componentname *,
-    ino_t);
+    ino_t *);
 
 /*
  * Convert a component of a pathname into a pointer to a locked inode.
@@ -134,12 +134,12 @@ ufs_lookup(ap)
 	} */ *ap;
 {
 
-	return (ufs_lookup_(ap->a_dvp, ap->a_vpp, ap->a_cnp, 0));
+	return (ufs_lookup_(ap->a_dvp, ap->a_vpp, ap->a_cnp, NULL));
 }
 
 static int
 ufs_lookup_(struct vnode *vdp, struct vnode **vpp, struct componentname *cnp,
-    ino_t dd_ino)
+    ino_t *dd_ino)
 {
 	struct inode *dp;		/* inode for directory being searched */
 	struct buf *bp;			/* a buffer of directory entries */
@@ -163,15 +163,9 @@ ufs_lookup_(struct vnode *vdp, struct vn
 	struct ucred *cred = cnp->cn_cred;
 	int flags = cnp->cn_flags;
 	int nameiop = cnp->cn_nameiop;
-	ino_t ino;
+	ino_t ino, ino1;
 	int ltype;
 
-	bp = NULL;
-	slotoffset = -1;
-/*
- *  XXX there was a soft-update diff about this I couldn't merge.
- * I think this was the equiv.
- */
 	if (vpp != NULL)
 		*vpp = NULL;
 
@@ -185,6 +179,12 @@ ufs_lookup_(struct vnode *vdp, struct vn
 	 */
 	vnode_create_vobject(vdp, DIP(dp, i_size), cnp->cn_thread);
 
+	bmask = VFSTOUFS(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
+
+restart:
+	bp = NULL;
+	slotoffset = -1;
+
 	/*
 	 * We now have a segment name to search for, and a directory to search.
 	 *
@@ -202,7 +202,6 @@ ufs_lookup_(struct vnode *vdp, struct vn
 		slotstatus = NONE;
 		slotneeded = DIRECTSIZ(cnp->cn_namelen);
 	}
-	bmask = VFSTOUFS(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
 
 #ifdef UFS_DIRHASH
 	/*
@@ -487,9 +486,8 @@ found:
 	if ((flags & ISLASTCN) && nameiop == LOOKUP)
 		dp->i_diroff = i_offset &~ (DIRBLKSIZ - 1);
 
-	if (dd_ino != 0) {
-		if (ino != dd_ino)
-			return (ENOENT);
+	if (dd_ino != NULL) {
+		*dd_ino = ino;
 		return (0);
 	}
 
@@ -600,11 +598,15 @@ found:
 		 * to the inode we looked up before vdp lock was
 		 * dropped.
 		 */
-		error = ufs_lookup_(pdp, NULL, cnp, ino);
+		error = ufs_lookup_(pdp, NULL, cnp, &ino1);
 		if (error) {
 			vput(tdp);
 			return (error);
 		}
+		if (ino1 != ino) {
+			vput(tdp);
+			goto restart;
+		}
 
 		*vpp = tdp;
 	} else if (dp->i_number == ino) {

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