Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6

* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
  [CIFS] Avoid open on possible directories since Samba now rejects them

1 files changed, 24 insertions, 19 deletions

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index f49d684edd96..3758965d73d5 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -657,31 +657,36 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
 	}
 	cFYI(1, ("Full path: %s inode = 0x%p", full_path, direntry->d_inode));
 
+	/* Posix open is only called (at lookup time) for file create now.
+	 * For opens (rather than creates), because we do not know if it
+	 * is a file or directory yet, and current Samba no longer allows
+	 * us to do posix open on dirs, we could end up wasting an open call
+	 * on what turns out to be a dir. For file opens, we wait to call posix
+	 * open till cifs_open.  It could be added here (lookup) in the future
+	 * but the performance tradeoff of the extra network request when EISDIR
+	 * or EACCES is returned would have to be weighed against the 50%
+	 * reduction in network traffic in the other paths.
+	 */
 	if (pTcon->unix_ext) {
 		if (!(nd->flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY)) &&
-		     (nd->flags & LOOKUP_OPEN) && !pTcon->broken_posix_open) {
-			if (!((nd->intent.open.flags & O_CREAT) &&
-					(nd->intent.open.flags & O_EXCL))) {
-				rc = cifs_posix_open(full_path, &newInode,
+		     (nd->flags & LOOKUP_OPEN) && !pTcon->broken_posix_open &&
+		     (nd->intent.open.flags & O_CREAT)) {
+			rc = cifs_posix_open(full_path, &newInode,
 					parent_dir_inode->i_sb,
 					nd->intent.open.create_mode,
 					nd->intent.open.flags, &oplock,
 					&fileHandle, xid);
-				/*
-				 * This code works around a bug in
-				 * samba posix open in samba versions 3.3.1
-				 * and earlier where create works
-				 * but open fails with invalid parameter.
-				 * If either of these error codes are
-				 * returned, follow the normal lookup.
-				 * Otherwise, the error during posix open
-				 * is handled.
-				 */
-				if ((rc != -EINVAL) && (rc != -EOPNOTSUPP))
-					posix_open = true;
-				else
-					pTcon->broken_posix_open = true;
-			}
+			/*
+			 * The check below works around a bug in POSIX
+			 * open in samba versions 3.3.1 and earlier where
+			 * open could incorrectly fail with invalid parameter.
+			 * If either that or op not supported returned, follow
+			 * the normal lookup.
+			 */
+			if ((rc == 0) || (rc == -ENOENT))
+				posix_open = true;
+			else if ((rc == -EINVAL) || (rc != -EOPNOTSUPP))
+				pTcon->broken_posix_open = true;
 		}
 		if (!posix_open)
 			rc = cifs_get_inode_info_unix(&newInode, full_path,