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Sender: Anna Schumaker <schumakeranna@gmail.com>
From:   schumaker.anna@gmail.com
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Cc:     Anna.Schumaker@Netapp.com
Subject: [PATCH v2 1/2] SUNRPC: Keep buf->len in sync with xdr->nwords when expanding holes
Date:   Tue,  8 Dec 2020 15:29:24 -0500
Message-Id: <20201208202925.597663-2-Anna.Schumaker@Netapp.com>
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From: Anna Schumaker <Anna.Schumaker@Netapp.com>

Otherwise we could end up placing data a few bytes off from where we
actually want to put it.

Fixes: 84ce182ab85b "SUNRPC: Add the ability to expand holes in data pages"
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
---
 net/sunrpc/xdr.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index 71e03b930b70..5b848fe65c81 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -1314,6 +1314,7 @@ uint64_t xdr_expand_hole(struct xdr_stream *xdr, uint64_t offset, uint64_t lengt
 		unsigned int res = _shift_data_right_tail(buf, from + bytes - shift, shift);
 		truncated = shift - res;
 		xdr->nwords -= XDR_QUADLEN(truncated);
+		buf->len -= 4 * XDR_QUADLEN(truncated);
 		bytes -= shift;
 	}
 
@@ -1325,7 +1326,7 @@ uint64_t xdr_expand_hole(struct xdr_stream *xdr, uint64_t offset, uint64_t lengt
 					bytes);
 	_zero_pages(buf->pages, buf->page_base + offset, length);
 
-	buf->len += length - (from - offset) - truncated;
+	buf->len += length - (from - offset);
 	xdr_set_page(xdr, offset + length, PAGE_SIZE);
 	return length;
 }
-- 
2.29.2