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: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/161789062190.6155.12711584466338493050.stgit@warthog.procyon.org.uk/ [1]
This commit is contained in:
David Howells 2021-04-26 21:16:16 +01:00
parent 3d14ec1fe6
commit 53b776c77a

View File

@ -933,7 +933,7 @@ cleanup:
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 @@ retry:
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);