| Message ID | 3726642.1619471184@warthog.procyon.org.uk |
|---|---|
| State | New |
| Headers | show |
| Series | netfs: Miscellaneous fixes | expand |
On Mon, Apr 26, 2021 at 10:06:24PM +0100, David Howells wrote: > @@ -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_offset(page); This one needs to use page_file_offset() because swap-over-NFS. > @@ -1105,8 +1105,8 @@ int netfs_write_begin(struct file *file, struct address_space *mapping, > rreq = netfs_alloc_read_request(ops, netfs_priv, file); > if (!rreq) > goto error; > - rreq->mapping = page->mapping; > - rreq->start = page->index * PAGE_SIZE; > + rreq->mapping = page_file_mapping(page); There's nothing wrong with using page->mapping here. The swap-over-NFS path doesn't use write_begin, it uses O_DIRECT writes.
diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c index 1d3b50c5db6d..568e26352309 100644 --- a/fs/netfs/read_helper.c +++ b/fs/netfs/read_helper.c @@ -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_offset(page); rreq->len = thp_size(page); if (ops->begin_cache_operation) { @@ -1105,8 +1105,8 @@ int netfs_write_begin(struct file *file, struct address_space *mapping, rreq = netfs_alloc_read_request(ops, netfs_priv, file); if (!rreq) goto error; - rreq->mapping = page->mapping; - rreq->start = page->index * PAGE_SIZE; + rreq->mapping = page_file_mapping(page); + 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);
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_offset() instead. (3) netfs_write_begin() should also use page_offset() to avoid the same overflow. (4) Use page_mapping() in netfs_write_begin() rather than page->mapping. Reported-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: David Howells <dhowells@redhat.com> Link: https://lore.kernel.org/r/161789062190.6155.12711584466338493050.stgit@warthog.procyon.org.uk/ [1] --- fs/netfs/read_helper.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)