| Message ID | 1415785780-3832-3-git-send-email-wangxg.fnst@cn.fujitsu.com |
|---|---|
| State | Superseded, archived |
| Headers | show |
diff --git a/misc/tune2fs.c b/misc/tune2fs.c index 91dc7c1..34d2cd9 100644 --- a/misc/tune2fs.c +++ b/misc/tune2fs.c @@ -2244,6 +2244,8 @@ static int expand_inode_table(ext2_filsys fs, unsigned long new_ino_size) /* Update the meta data */ fs->inode_blocks_per_group = new_ino_blks_per_grp; + ext2fs_free_inode_cache(fs->icache); + fs->icache = 0; fs->super->s_inode_size = new_ino_size; err_out:
If we apply this patch 'e2fsprogs/tune2fs: rewrite metadata checksums when resizing inode size', we will trigger a segfault, this is because of the inode cache issues. Firstly we should notice that in expand_inode_table(), we have change the super block's s_inode_size to new inode size(for example, 256). Then we re-compute metadata checksums, see below code flow: |-->rewrite_metadata_checksums |----->rewrite_inodes |-------->ext2fs_write_inode_full In ext2fs_write_inode_full(), if an inode cache is hit, the below code will be executed: /* Check to see if the inode cache needs to be updated */ if (fs->icache) { for (i=0; i < fs->icache->cache_size; i++) { if (fs->icache->cache[i].ino == ino) { memcpy(fs->icache->cache[i].inode, inode, (bufsize > length) ? length : bufsize); break; } } } Before executing rewrite_inodes(), actually the inode in inode cache is allocated by old inode size(for example, 128), but here the memcpy will obviously write overflow, '(bufsize > length) ? length : bufsize' here will return 256(new inode size), so this is wrong, we need to fix this. I think we should call ext2fs_free_inode_cache() in expand_inode_table(), to drop the inode cache, because inode size has changed, if necessary, we will re-create this inode cache. Steps to reproduce this bug(apply 'e2fsprogs/tune2fs: rewrite metadata checksums when resizing inode size' first). dd if=/dev/zero of=file.img bs=1M count=128 device_name=$(/sbin/losetup -f) /sbin/losetup -f file.img mkfs.ext4 -I 128 -O ^flex_bg $device_name tune2fs -I 256 $device_name Signed-off-by: Xiaoguang Wang <wangxg.fnst@cn.fujitsu.com> --- misc/tune2fs.c | 2 ++ 1 file changed, 2 insertions(+)