This is a note to let you know that I've just added the patch titled
nfsd_splice_actor(): handle compound pages
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsd_splice_actor-handle-compound-pages.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit c34305b052c2bb7a246929aaeed1eb3a1392fb53
Author: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Date: Sat Sep 10 22:14:02 2022 +0100
nfsd_splice_actor(): handle compound pages
[ Upstream commit bfbfb6182ad1d7d184b16f25165faad879147f79 ]
pipe_buffer might refer to a compound page (and contain more than a PAGE_SIZE
worth of data). Theoretically it had been possible since way back, but
nfsd_splice_actor() hadn't run into that until copy_page_to_iter() change.
Fortunately, the only thing that changes for compound pages is that we
need to stuff each relevant subpage in and convert the offset into offset
in the first subpage.
Acked-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Tested-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
Fixes: f0f6b614f83d "copy_page_to_iter(): don't split high-order page in case of ITER_PIPE"
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
[ cel: "‘for’ loop initial declarations are only allowed in C99 or C11 mode" ]
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 95f2e4549c034..bc377ee177171 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -862,10 +862,15 @@ nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
struct splice_desc *sd)
{
struct svc_rqst *rqstp = sd->u.data;
-
- svc_rqst_replace_page(rqstp, buf->page);
- if (rqstp->rq_res.page_len == 0)
- rqstp->rq_res.page_base = buf->offset;
+ struct page *page = buf->page; // may be a compound one
+ unsigned offset = buf->offset;
+ int i;
+
+ page += offset / PAGE_SIZE;
+ for (i = sd->len; i > 0; i -= PAGE_SIZE)
+ 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;
return sd->len;
}
