| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.13 096/104] SMB3: fix readpage for large swap cache | Date | Mon, 2 Aug 2021 15:45:33 +0200 |
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From: Steve French <stfrench@microsoft.com>
commit f2a26a3cff27dfa456fef386fe5df56dcb4b47b6 upstream.
readpage was calculating the offset of the page incorrectly for the case of large swapcaches.
loff_t offset = (loff_t)page->index << PAGE_SHIFT;
As pointed out by Matthew Wilcox, this needs to use page_file_offset() to calculate the offset instead. Pages coming from the swap cache have page->index set to their index within the swapcache, not within the backing file. For a sufficiently large swapcache, we could have overlapping values of page->index within the same backing file.
Suggested by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: <stable@vger.kernel.org> # v5.7+ Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- fs/cifs/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -4631,7 +4631,7 @@ read_complete: static int cifs_readpage(struct file *file, struct page *page) { - loff_t offset = (loff_t)page->index << PAGE_SHIFT; + loff_t offset = page_file_offset(page); int rc = -EACCES; unsigned int xid;
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