dir_index: error out instead of BUG on corrupt dx dirs

Convert asserts (BUGs) in dx_probe from bad on-disk data to recoverable
errors with helpful warnings.  With help catching other asserts from Duane
Griffin <duaneg@dghda.com>

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Acked-by: Duane Griffin <duaneg@dghda.com>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 30 insertions, 4 deletions

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index da224974af78..9468289637a5 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -379,13 +379,28 @@ dx_probe(struct dentry *dentry, struct inode *dir,
 
         entries = (struct dx_entry *) (((char *)&root->info) +
                                        root->info.info_length);
-        assert(dx_get_limit(entries) == dx_root_limit(dir,
-                                                      root->info.info_length));
+
+        if (dx_get_limit(entries) != dx_root_limit(dir,
+                                                   root->info.info_length)) {
+                ext4_warning(dir->i_sb, __FUNCTION__,
+                             "dx entry: limit != root limit");
+                brelse(bh);
+                *err = ERR_BAD_DX_DIR;
+                goto fail;
+        }
+
         dxtrace (printk("Look up %x", hash));
         while (1)
         {
                 count = dx_get_count(entries);
-                assert (count && count <= dx_get_limit(entries));
+                if (!count || count > dx_get_limit(entries)) {
+                        ext4_warning(dir->i_sb, __FUNCTION__,
+                                     "dx entry: no count or count > limit");
+                        brelse(bh);
+                        *err = ERR_BAD_DX_DIR;
+                        goto fail2;
+                }
+
                 p = entries + 1;
                 q = entries + count - 1;
                 while (p <= q)
@@ -423,8 +438,15 @@ dx_probe(struct dentry *dentry, struct inode *dir,
                 if (!(bh = ext4_bread (NULL,dir, dx_get_block(at), 0, err)))
                         goto fail2;
                 at = entries = ((struct dx_node *) bh->b_data)->entries;
-                assert (dx_get_limit(entries) == dx_node_limit (dir));
+                if (dx_get_limit(entries) != dx_node_limit (dir)) {
+                        ext4_warning(dir->i_sb, __FUNCTION__,
+                                     "dx entry: limit != node limit");
+                        brelse(bh);
+                        *err = ERR_BAD_DX_DIR;
+                        goto fail2;
+                }
                 frame++;
+                frame->bh = NULL;
         }
 fail2:
         while (frame >= frame_in) {
@@ -432,6 +454,10 @@ fail2:
                 frame--;
         }
 fail:
+        if (*err == ERR_BAD_DX_DIR)
+                ext4_warning(dir->i_sb, __FUNCTION__,
+                             "Corrupt dir inode %ld, running e2fsck is "
+                             "recommended.", dir->i_ino);
         return NULL;
 }