From: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Date: Tue, 6 Sep 2016 02:36:43 +0000 (+0200)
Subject: ext4: Do not crash when trying to grow a directory using extents
X-Git-Tag: v2016.11-rc1~93
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=b96c3c7292214fb81b1b355bf5a6d53cf9996d1e;p=oweals%2Fu-boot.git

ext4: Do not crash when trying to grow a directory using extents

The following command crashes u-boot:
./sandbox/u-boot -c 'i=0; host bind 0 ./sandbox/test/fs/3GB.ext4.img ;
  while test $i -lt 200 ; do echo $i; setexpr i $i + 1;
  ext4write host 0 0 /foobar${i} 0; done'

Previously, the code updated the direct_block even for extents, and
fortunately crashed before pushing garbage to the disk.

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>
---

diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c
index 680e0011cc..eebca7de91 100644
--- a/fs/ext4/ext4_common.c
+++ b/fs/ext4/ext4_common.c
@@ -453,8 +453,13 @@ restart:
 			    sizeof(struct ext2_dirent) + padding_factor;
 			if ((fs->blksz - totalbytes - last_entry_dirlen) <
 				new_entry_byte_reqd) {
-				printf("1st Block Full:Allocate new block\n");
+				printf("Last Block Full:Allocate new block\n");
 
+				if (le32_to_cpu(g_parent_inode->flags) &
+						EXT4_EXTENTS_FL) {
+					printf("Directory uses extents\n");
+					goto fail;
+				}
 				if (direct_blk_idx == INDIRECT_BLOCKS - 1) {
 					printf("Directory exceeds limit\n");
 					goto fail;