[PATCH v1 3/3] io_uring/rsrc: fix lost entries after cloned range

[Joanne Koong <joannelkoong@gmail.com>]

When cloning with node replacements (IORING_REGISTER_DST_REPLACE),
destination entries after the cloned range are not copied over.

Add logic to copy them over to the new destination table.

Fixes: c1329532d5aa ("io_uring/rsrc: allow cloning with node replacements")
Cc: stable@vger.kernel.org
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
---
 io_uring/rsrc.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index 04f56212398a..a63474b331bf 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -1205,7 +1205,7 @@ static int io_clone_buffers(struct io_ring_ctx *ctx, struct io_ring_ctx *src_ctx
 	if (ret)
 		return ret;
 
-	/* Fill entries in data from dst that won't overlap with src */
+	/* Copy original dst nodes from before the cloned range */
 	for (i = 0; i < min(arg->dst_off, ctx->buf_table.nr); i++) {
 		struct io_rsrc_node *node = ctx->buf_table.nodes[i];
 
@@ -1238,6 +1238,16 @@ static int io_clone_buffers(struct io_ring_ctx *ctx, struct io_ring_ctx *src_ctx
 		i++;
 	}
 
+	/* Copy original dst nodes from after the cloned range */
+	for (i = nbufs; i < ctx->buf_table.nr; i++) {
+		struct io_rsrc_node *node = ctx->buf_table.nodes[i];
+
+		if (node) {
+			data.nodes[i] = node;
+			node->refs++;
+		}
+	}
+
 	/*
 	 * If asked for replace, put the old table. data->nodes[] holds both
 	 * old and new nodes at this point.
-- 
2.47.3