Re: [RFC] v9fs: readpage support

[Christoph Hellwig <hch@infradead.org>]

> +/*
> + * v9fs_vfs_readpage - read an entire page in from 9P
> + *
> + * @file: file being read 
> + * @page: structure to page
> + *
> + */

this isn't actually a valid kerneldoc comment, they start with /**
e.g.

/**
 * v9fs_vfs_readpage  -  read an entire page in from 9P
 * @file: file being read
 * @page: structure to page
 */

not that I think kerneldoc comments on implementations driver / fs API
methods are very useful in general..
 
> +	loff_t offset = ((loff_t) page->index) << PAGE_CACHE_SHIFT;

please use the page_offset() helper.

> +	struct v9fs_fcall *fcall = NULL;
> +	int fid = v9f->fid;
> +	int total = 0;
> +	int result = 0;
> +
> +	page_cache_get(page);

->readpage is synchronous, so you shouldn't need to grab a reference.

> +	if (PageError(page))
> +		ClearPageError(page);

this doesn't make a lot of sense.

> +	retval = 0;
> +
> +      Error:

labels always at positions zero or one please.  I'd call this out
instead of erorr aswell as it's used for the successfull completion
case aswell.

> diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
> index 89c849d..f332f65 100644
> --- a/fs/9p/vfs_file.c
> +++ b/fs/9p/vfs_file.c
> @@ -306,6 +306,9 @@ v9fs_file_write(struct file *filp, const
>  		total += result;
>  	} while (count);
>  
> +	if ((inode->i_mapping) && (inode->i_mapping->nrpages))
> +		invalidate_inode_pages2(inode->i_mapping);
> +

how could inode->i_mapping be zero here?  Also the parenthes around
those values are superflous.