From ac8db824ead0de2e9111337c401409d010fba2f0 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Wed, 23 Nov 2022 14:14:32 -0500 Subject: [PATCH] NFSD: Fix reads with a non-zero offset that don't end on a page boundary This was found when virtual machines with nfs-mounted qcow2 disks failed to boot properly. Reported-by: Anders Blomdell Suggested-by: Al Viro Link: https://bugzilla.redhat.com/show_bug.cgi?id=2142132 Fixes: bfbfb6182ad1 ("nfsd_splice_actor(): handle compound pages") Signed-off-by: Chuck Lever --- fs/nfsd/vfs.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 83be899..31bc7cc 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -871,10 +871,11 @@ nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf, struct svc_rqst *rqstp = sd->u.data; struct page *page = buf->page; // may be a compound one unsigned offset = buf->offset; + struct page *last_page; - page += offset / PAGE_SIZE; - for (int i = sd->len; i > 0; i -= PAGE_SIZE) - svc_rqst_replace_page(rqstp, page++); + last_page = page + (offset + sd->len - 1) / PAGE_SIZE; + for (page += offset / PAGE_SIZE; page <= last_page; page++) + svc_rqst_replace_page(rqstp, page); if (rqstp->rq_res.page_len == 0) // first call rqstp->rq_res.page_base = offset % PAGE_SIZE; rqstp->rq_res.page_len += sd->len; -- 2.7.4