[PATCH 6.14] orangefs: adjust counting code to recover from 665575cf

[hubcap@kernel.org]

From: Mike Marshall <hubcap@omnibond.com>

A late commit to 6.14-rc7 (665575cf) broke orangefs. I made a patch that
fixes orangefs in 6.15, but some pagecache/folio code got pulled into
6.15 that causes my 6.15 patch not to apply to 6.14. Here is a tested
6.14 flavored patch that was never upstream that I hope can get applied
to 6.14-stable...

---
 fs/orangefs/inode.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/orangefs/inode.c b/fs/orangefs/inode.c
index aae6d2b8767d..3e8ce0fea4d7 100644
--- a/fs/orangefs/inode.c
+++ b/fs/orangefs/inode.c
@@ -32,12 +32,13 @@ static int orangefs_writepage_locked(struct page *page,
 	len = i_size_read(inode);
 	if (PagePrivate(page)) {
 		wr = (struct orangefs_write_range *)page_private(page);
-		WARN_ON(wr->pos >= len);
 		off = wr->pos;
-		if (off + wr->len > len)
+		if ((off + wr->len > len) && (off <= len))
 			wlen = len - off;
 		else
 			wlen = wr->len;
+		if (wlen == 0)
+			wlen = wr->len;
 	} else {
 		WARN_ON(1);
 		off = page_offset(page);
@@ -46,8 +47,6 @@ static int orangefs_writepage_locked(struct page *page,
 		else
 			wlen = PAGE_SIZE;
 	}
-	/* Should've been handled in orangefs_invalidate_folio. */
-	WARN_ON(off == len || off + wlen > len);
 
 	WARN_ON(wlen == 0);
 	bvec_set_page(&bv, page, wlen, off % PAGE_SIZE);
@@ -341,6 +340,8 @@ static int orangefs_write_begin(struct file *file,
 			wr->len += len;
 			goto okay;
 		} else {
+			wr->pos = pos;
+			wr->len = len;
 			ret = orangefs_launder_folio(folio);
 			if (ret)
 				return ret;
-- 
2.49.0