ext4: Fix duplicate entries returned from getdents() system call
Theodore Ts'o [Sat, 25 Oct 2008 15:39:08 +0000 (11:39 -0400)]
Fix a regression caused by commit d0156417, "ext4: fix ext4_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.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

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>

fs/ext4/dir.c

index 3ca6a2b..fed5b61 100644 (file)
@@ -459,17 +459,8 @@ static int ext4_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 = EXT4_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);
 
@@ -501,9 +492,14 @@ static int ext4_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 = EXT4_HTREE_EOF;
                                break;