From: Zhang Yi <yi.zhang@huawei.com> hulk inclusion category: bugfix bugzilla: 174653, https://gitee.com/openeuler/kernel/issues/I476C7 CVE: NA --------------------------- In ext4_get_inode_loc(), we may skip IO and get an zero && uptodate inode buffer when the inode monopolize an inode block for performance reason. For most cases, ext4_mark_iloc_dirty() will fill the inode buffer to make it fine, but we could miss this call if something bad happened. Finally, __ext4_get_inode_loc_noinmem() may probably get an empty inode buffer and trigger ext4 error. For example, if we remove a nonexistent xattr on inode A, ext4_xattr_set_handle() will return ENODATA before invoking ext4_mark_iloc_dirty(), it will left an uptodate but zero buffer. We will get checksum error message in ext4_iget() when getting inode again. EXT4-fs error (device sda): ext4_lookup:1784: inode #131074: comm cat: iget: checksum invalid Even worse, if we allocate another inode B at the same inode block, it will corrupt the inode A on disk when write back inode B. So this patch initialize the inode buffer by filling the in-mem inode contents if we skip read I/O, ensure that the buffer is really uptodate. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Yang Erkun <yangerkun@huawei.com> Reviewed-by: Xie Miao <miaoxie@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- fs/ext4/inode.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 8c20b4d6da9be..b1bede3c489e7 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4824,8 +4824,13 @@ static int __ext4_get_inode_loc(struct inode *inode, } brelse(bitmap_bh); if (i == start + inodes_per_block) { + struct ext4_inode *raw_inode = + (struct ext4_inode *) (bh->b_data + iloc->offset); + /* all other inodes are free, so skip I/O */ memset(bh->b_data, 0, bh->b_size); + if (!ext4_test_inode_state(inode, EXT4_STATE_NEW)) + ext4_fill_raw_inode(inode, raw_inode); set_buffer_uptodate(bh); unlock_buffer(bh); goto has_buffer; -- 2.25.1