Skip site navigation (1)Skip section navigation (2) 
Date:      Thu, 9 Jul 2015 16:32:59 +0000 (UTC)
From:      Mateusz Guzik <mjg@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r285326 - head/sys/kern
Message-ID:  <201507091632.t69GWxSo046035@repo.freebsd.org>
next in thread | raw e-mail | index | archive | help 
Author: mjg
Date: Thu Jul  9 16:32:58 2015
New Revision: 285326
URL: https://svnweb.freebsd.org/changeset/base/285326

Log:
  vfs: simplify error handling in namei
  
  The logic is reorganised so that there is one exit point prior to the
  lookup loop. This is an intermediate step to making audit logging
  functions use found vnode instead of translating ni_dirfd on their own.
  
  ni_startdir validation is removed. The only in-tree consumer is nfs
  which already makes sure it is a directory.
  
  Reviewed by:	kib

Modified:
  head/sys/kern/vfs_lookup.c

Modified: head/sys/kern/vfs_lookup.c
==============================================================================
--- head/sys/kern/vfs_lookup.c	Thu Jul  9 16:28:36 2015	(r285325)
+++ head/sys/kern/vfs_lookup.c	Thu Jul  9 16:32:58 2015	(r285326)
@@ -158,7 +158,7 @@ namei(struct nameidata *ndp)
 	struct vnode *dp;	/* the directory we are searching */
 	struct iovec aiov;		/* uio for reading symbolic links */
 	struct uio auio;
-	int error, linklen;
+	int error, linklen, startdir_used;
 	struct componentname *cnp = &ndp->ni_cnd;
 	struct thread *td = cnp->cn_thread;
 	struct proc *p = td->td_proc;
@@ -169,6 +169,8 @@ namei(struct nameidata *ndp)
 	    ("namei: nameiop contaminated with flags"));
 	KASSERT((cnp->cn_flags & OPMASK) == 0,
 	    ("namei: flags contaminated with nameiops"));
+	MPASS(ndp->ni_startdir == NULL || ndp->ni_startdir->v_type == VDIR ||
+	    ndp->ni_startdir->v_type == VBAD);
 	if (!lookup_shared)
 		cnp->cn_flags &= ~LOCKSHARED;
 	fdp = p->p_fd;
@@ -242,23 +244,19 @@ namei(struct nameidata *ndp)
 	if (cnp->cn_flags & AUDITVNODE2)
 		AUDIT_ARG_UPATH2(td, ndp->ni_dirfd, cnp->cn_pnbuf);
 
+	startdir_used = 0;
 	dp = NULL;
 	cnp->cn_nameptr = cnp->cn_pnbuf;
 	if (cnp->cn_pnbuf[0] == '/') {
 		error = namei_handle_root(ndp, &dp);
-		FILEDESC_SUNLOCK(fdp);
-		if (error != 0) {
-			vrele(ndp->ni_rootdir);
-			if (ndp->ni_startdir != NULL)
-				vrele(ndp->ni_startdir);
-			namei_cleanup_cnp(cnp);
-			return (error);
-		}
 	} else {
 		if (ndp->ni_startdir != NULL) {
 			dp = ndp->ni_startdir;
-			error = 0;
-		} else if (ndp->ni_dirfd != AT_FDCWD) {
+			startdir_used = 1;
+		} else if (ndp->ni_dirfd == AT_FDCWD) {
+			dp = fdp->fd_cdir;
+			VREF(dp);
+		} else {
 			cap_rights_t rights;
 
 			rights = ndp->ni_rightsneeded;
@@ -285,25 +283,18 @@ namei(struct nameidata *ndp)
 			}
 #endif
 		}
-		if (error != 0 || dp != NULL) {
-			FILEDESC_SUNLOCK(fdp);
-			if (error == 0 && dp->v_type != VDIR) {
-				vrele(dp);
-				error = ENOTDIR;
-			}
-		}
-		if (error) {
-			vrele(ndp->ni_rootdir);
-			namei_cleanup_cnp(cnp);
-			return (error);
-		}
+		if (error == 0 && dp->v_type != VDIR)
+			error = ENOTDIR;
 	}
-	if (dp == NULL) {
-		dp = fdp->fd_cdir;
-		VREF(dp);
-		FILEDESC_SUNLOCK(fdp);
-		if (ndp->ni_startdir != NULL)
-			vrele(ndp->ni_startdir);
+	FILEDESC_SUNLOCK(fdp);
+	if (ndp->ni_startdir != NULL && !startdir_used)
+		vrele(ndp->ni_startdir);
+	if (error != 0) {
+		if (dp != NULL)
+			vrele(dp);
+		vrele(ndp->ni_rootdir);
+		namei_cleanup_cnp(cnp);
+		return (error);
 	}
 	SDT_PROBE(vfs, namei, lookup, entry, dp, cnp->cn_pnbuf,
 	    cnp->cn_flags, 0, 0);

Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201507091632.t69GWxSo046035>