Commit 53b776c7 authored by David Howells's avatar David Howells
Browse files

netfs: Miscellaneous fixes 



Fix some miscellaneous things in the new netfs lib[1]:

 (1) The kerneldoc for netfs_readpage() shouldn't say netfs_page().

 (2) netfs_readpage() can get an integer overflow on 32-bit when it
     multiplies page_index(page) by PAGE_SIZE.  It should use
     page_file_offset() instead.

 (3) netfs_write_begin() should use page_offset() to avoid the same
     overflow.

Note that netfs_readpage() needs to use page_file_offset() rather than
page_offset() as it may see swap-over-NFS.

Reported-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Reviewed-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/161789062190.6155.12711584466338493050.stgit@warthog.procyon.org.uk/ [1]
parent 3d14ec1f

fs/netfs/read_helper.c

+3 −3
Original line number Diff line number Diff line
@@ -933,7 +933,7 @@ void netfs_readahead(struct readahead_control *ractl, 
EXPORT_SYMBOL(netfs_readahead);



/**

 * netfs_page - Helper to manage a readpage request

 * netfs_readpage - Helper to manage a readpage request

 * @file: The file to read from

 * @page: The page to read

 * @ops: The network filesystem's operations for the helper to use
@@ -968,7 +968,7 @@ int netfs_readpage(struct file *file, 
		return -ENOMEM;

	}

	rreq->mapping	= page_file_mapping(page);

	rreq->start	= page_index(page) * PAGE_SIZE;

	rreq->start	= page_file_offset(page);

	rreq->len	= thp_size(page);



	if (ops->begin_cache_operation) {
@@ -1106,7 +1106,7 @@ int netfs_write_begin(struct file *file, struct address_space *mapping, 
	if (!rreq)

		goto error;

	rreq->mapping		= page->mapping;

	rreq->start		= page->index * PAGE_SIZE;

	rreq->start		= page_offset(page);

	rreq->len		= thp_size(page);

	rreq->no_unlock_page	= page->index;

	__set_bit(NETFS_RREQ_NO_UNLOCK_PAGE, &rreq->flags);