Re: [PATCH] mm: adjust max read count in generic_file_buffered_read()

On Fri 20-07-18 16:14:29, Andrew Morton wrote:

On Thu, 19 Jul 2018 10:58:12 +0200 Jan Kara [off-list ref] wrote:

quoted

On Thu 19-07-18 16:17:26, Chengguang Xu wrote:

quoted

When we try to truncate read count in generic_file_buffered_read(),
should deliver (sb->s_maxbytes - offset) as maximum count not
sb->s_maxbytes itself.

Signed-off-by: Chengguang Xu <redacted>

Looks good to me. You can add:

Reviewed-by: Jan Kara <jack@suse.cz>

Yup.

What are the runtime effects of this bug?

Good question. I think ->readpage() could be called for index beyond
maximum file size supported by the filesystem leading to weird filesystem
behavior due to overflows in internal calculations.

								Honza
-- 
Jan Kara [off-list ref]
SUSE Labs, CR