From: Theodore Ts'o <tytso@mit.edu>
Date: Sat, 25 Oct 2008 15:38:37 +0000 (-0400)
Subject: ext3: Fix duplicate entries returned from getdents() system call
X-Git-Tag: v2.6.28-rc2~10^2~1
X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?p=linux-2.6-omap-h63xx.git;a=commitdiff_plain;h=8c9fa93d51123c5540762b1a9e1919d6f9c4af7c

ext3: Fix duplicate entries returned from getdents() system call

Fix a regression caused by commit 6a897cf4, "ext3: fix ext3_dx_readdir
hash collision handling", where deleting files in a large directory
(requiring more than one getdents system call), results in some
filenames being returned twice.  This was caused by a failure to
update info->curr_hash and info->curr_minor_hash, so that if the
directory had gotten modified since the last getdents() system call
(as would be the case if the user is running "rm -r" or "git clean"),
a directory entry would get returned twice to the userspace.

This patch fixes the bug reported by Markus Trippelsdorf at:
http://bugzilla.kernel.org/show_bug.cgi?id=11844

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Tested-by: Markus Trippelsdorf <markus@trippelsdorf.de>
---

diff --git a/fs/ext3/dir.c b/fs/ext3/dir.c
index 4c82531ea0a..5853f4440af 100644
--- a/fs/ext3/dir.c
+++ b/fs/ext3/dir.c
@@ -456,17 +456,8 @@ static int ext3_dx_readdir(struct file * filp,
 	if (info->extra_fname) {
 		if (call_filldir(filp, dirent, filldir, info->extra_fname))
 			goto finished;
-
 		info->extra_fname = NULL;
-		info->curr_node = rb_next(info->curr_node);
-		if (!info->curr_node) {
-			if (info->next_hash == ~0) {
-				filp->f_pos = EXT3_HTREE_EOF;
-				goto finished;
-			}
-			info->curr_hash = info->next_hash;
-			info->curr_minor_hash = 0;
-		}
+		goto next_node;
 	} else if (!info->curr_node)
 		info->curr_node = rb_first(&info->root);
 
@@ -498,9 +489,14 @@ static int ext3_dx_readdir(struct file * filp,
 		info->curr_minor_hash = fname->minor_hash;
 		if (call_filldir(filp, dirent, filldir, fname))
 			break;
-
+	next_node:
 		info->curr_node = rb_next(info->curr_node);
-		if (!info->curr_node) {
+		if (info->curr_node) {
+			fname = rb_entry(info->curr_node, struct fname,
+					 rb_hash);
+			info->curr_hash = fname->hash;
+			info->curr_minor_hash = fname->minor_hash;
+		} else {
 			if (info->next_hash == ~0) {
 				filp->f_pos = EXT3_HTREE_EOF;
 				break;