pnfs: allow splicing pre-encoded pages into the layoutcommit args
Currently there is no XDR buffer space allocated for the per-layout driver
layoutcommit payload, which leads to server buffer overflows in the
blocklayout driver even under simple workloads. As we can't do per-layout
sizes for XDR operations we'll have to splice a previously encoded list
of pages into the XDR stream, similar to how we handle ACL buffers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index e13b59d..f2cd957 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -395,7 +395,10 @@
2 /* last byte written */ + \
1 /* nt_timechanged (false) */ + \
1 /* layoutupdate4 layout type */ + \
- 1 /* NULL filelayout layoutupdate4 payload */)
+ 1 /* layoutupdate4 opaqueue len */)
+ /* the actual content of layoutupdate4 should
+ be allocated by drivers and spliced in
+ using xdr_write_pages */
#define decode_layoutcommit_maxsz (op_decode_hdr_maxsz + 3)
#define encode_layoutreturn_maxsz (8 + op_encode_hdr_maxsz + \
encode_stateid_maxsz + \
@@ -1990,7 +1993,7 @@
static int
encode_layoutcommit(struct xdr_stream *xdr,
struct inode *inode,
- const struct nfs4_layoutcommit_args *args,
+ struct nfs4_layoutcommit_args *args,
struct compound_hdr *hdr)
{
__be32 *p;
@@ -2011,11 +2014,16 @@
*p++ = cpu_to_be32(0); /* Never send time_modify_changed */
*p++ = cpu_to_be32(NFS_SERVER(args->inode)->pnfs_curr_ld->id);/* type */
- if (NFS_SERVER(inode)->pnfs_curr_ld->encode_layoutcommit)
+ if (NFS_SERVER(inode)->pnfs_curr_ld->encode_layoutcommit) {
NFS_SERVER(inode)->pnfs_curr_ld->encode_layoutcommit(
NFS_I(inode)->layout, xdr, args);
- else
- encode_uint32(xdr, 0); /* no layout-type payload */
+ } else {
+ encode_uint32(xdr, args->layoutupdate_len);
+ if (args->layoutupdate_pages) {
+ xdr_write_pages(xdr, args->layoutupdate_pages, 0,
+ args->layoutupdate_len);
+ }
+ }
return 0;
}