On Sat, Mar 12, 2016 at 09:39:22PM -0500, Theodore Ts'o wrote:
> On Fri, Mar 11, 2016 at 11:38:53PM +0800, Eryu Guan wrote:
> > ext4_reserve_inode_write() in ext4_mark_inode_dirty() could fail on
> > error (e.g. EIO) and iloc.bh can be NULL in this case. But the error is
> > ignored in the following "if" condition and ext4_expand_extra_isize()
> > might be called with NULL iloc.bh set, which triggers NULL pointer
> > dereference.
>
> Nice catch! I'm going fix this slightly differently (although I'll
> keep your description). The patch is a wee bit bigger, but the end
> result is simpler to read.
Yes, it's more easier to read. Thanks!
Eryu
>
> Thanks,
>
> - Ted
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index ce2c4c6..b41432e 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -5312,6 +5312,8 @@ int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
> might_sleep();
> trace_ext4_mark_inode_dirty(inode, _RET_IP_);
> err = ext4_reserve_inode_write(handle, inode, &iloc);
> + if (err)
> + return err;
> if (ext4_handle_valid(handle) &&
> EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
> !ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
> @@ -5342,9 +5344,7 @@ int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
> }
> }
> }
> - if (!err)
> - err = ext4_mark_iloc_dirty(handle, inode, &iloc);
> - return err;
> + return ext4_mark_iloc_dirty(handle, inode, &iloc);
> }
>
> /*
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