[patch 100/104] ext3: Fix duplicate entries returned from getdents() system call

Greg KH
2008-12-03T20:30:45Z

[-- Attachment #1: ext3-fix-duplicate-entries-returned-from-getdents-system-call.patch --]
[-- Type: text/plain, Size: 2231 bytes --]

2.6.27-stable review patch. If anyone has any objections, please let us know.

------------------
From: Theodore Ts'o <tytso@mit.edu>

commit 8c9fa93d51123c5540762b1a9e1919d6f9c4af7c upstream.

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>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
fs/ext3/dir.c | 20 ++++++++------------
1 file changed, 8 insertions(+), 12 deletions(-)

--- a/fs/ext3/dir.c
+++ b/fs/ext3/dir.c
@@ -456,17 +456,8 @@ static int ext3_dx_readdir(struct file *
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 *
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;