From bfc8e67c60b911ee5605c1234fcb58239e5c20de Mon Sep 17 00:00:00 2001 From: Steve French Date: Fri, 23 Jul 2021 18:35:15 -0500 Subject: [PATCH] SMB3: fix readpage for large swap cache 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) Cc: # v5.7+ Reviewed-by: Ronnie Sahlberg Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/cifs/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/cifs/file.c b/fs/cifs/file.c index da057570bb93..f46904a4ead3 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -4550,7 +4550,7 @@ 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;