Re: [RESEND4, PATCH 1/2] fuse: retrieve: cap requested size to negotiated max_write

On Wed, Apr 24, 2019 at 02:17:27PM +0200, Miklos Szeredi wrote:

On Wed, Apr 24, 2019 at 1:56 PM Kirill Smelkov kirr@nexedi.com wrote:

...

I assume you are meaning this:

    --- a/fs/fuse/dev.c
    +++ b/fs/fuse/dev.c
    @@ -1745,15 +1745,15 @@ static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
            unsigned int offset;
            size_t total_len = 0;
            unsigned int num_pages;

            offset = outarg->offset & ~PAGE_MASK;
            file_size = i_size_read(inode);

    -       num = outarg->size;
    +       num = min(outarg->size, fc->max_write);
            if (outarg->offset > file_size)
                    num = 0;
            else if (outarg->offset + num > file_size)
                    num = file_size - outarg->offset;               <-- THIS

            num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
            num_pages = min(num_pages, fc->max_pages);

and then in this case (offset + num > file_size) num overwrite

    num = file_size - offset

can make num only smaller, right? And then the patch is not wrong because there is no other num overwriting in this function except when num is being further decremented in loop that prepares pages to retrieve.

You're right, of course.

Thanks. Does it mean that the patch is ok? Do I need to rework something?

...

...

Also the patch is whitespace damaged.

I've tried to do the following in my mutt on "RESEND4, PATCH 1/2" message:

    |(cd ~/src/linux/linux && git am -)

and the patch applied successfully. So could you please clarify what "whitespace damaged" means?

Hmm, apparently this (and only this) message is "quoted-printable" encoded. git-am seems to handle it fine, but my script doesn't. Anyway, I'll do it manually.

I see. Probably it is not "quoted-printable" as

Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit

suggests and it is maybe due to UTF-8 characters (I used "·" several times in patch description). Anyway if it helps you can pull the patch from here

https://lab.nexedi.com/kirr/linux.git y/fuse-retrieve-cap-max_write and then cherry-pick it (git cherry-pick fd482f96537a) to where needed.

Thanks again for feedback,

Kirill