From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
I ran into this corner case in testing: in theory clients can provide
state owners up to 1024 bytes long. In the sessions case there might be
a risk of this pushing us over the DRC slot size.
The conflicting owner isn't really that important, so let's humor a
client that provides a small maxresponsize_cached by allowing ourselves
to return without the conflicting owner instead of outright failing the
operation.
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
---
fs/nfsd/nfs4proc.c | 3 ++-
fs/nfsd/nfs4xdr.c | 16 +++++++++++++---
2 files changed, 15 insertions(+), 4 deletions(-)
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 787aa9f..be638c1 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1381,7 +1381,8 @@ out:
#define op_encode_change_info_maxsz (5)
#define nfs4_fattr_bitmap_maxsz (4)
-#define op_encode_lockowner_maxsz (1 + XDR_QUADLEN(IDMAP_NAMESZ))
+/* We'll fall back on returning no lockowner if run out of space: */
+#define op_encode_lockowner_maxsz (0)
#define op_encode_lock_denied_maxsz (8 + op_encode_lockowner_maxsz)
#define nfs4_owner_maxsz (1 + XDR_QUADLEN(IDMAP_NAMESZ))
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 6c3ac43..d418d7e 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2862,9 +2862,20 @@ nfsd4_encode_lock_denied(struct xdr_stream *xdr, struct nfsd4_lock_denied *ld)
struct xdr_netobj *conf = &ld->ld_owner;
__be32 *p;
+again:
p = xdr_reserve_space(xdr, 32 + XDR_LEN(conf->len));
- if (!p)
+ if (!p) {
+ /*
+ * Don't fail to return the result just because we can't
+ * return the conflicting open:
+ */
+ if (conf->len) {
+ conf->len = 0;
+ conf->data = NULL;
+ goto again;
+ }
return nfserr_resource;
+ }
WRITE64(ld->ld_start);
WRITE64(ld->ld_length);
WRITE32(ld->ld_type);
@@ -2872,7 +2883,6 @@ nfsd4_encode_lock_denied(struct xdr_stream *xdr, struct nfsd4_lock_denied *ld)
WRITEMEM(&ld->ld_clientid, 8);
WRITE32(conf->len);
WRITEMEM(conf->data, conf->len);
- kfree(conf->data);
} else { /* non - nfsv4 lock in conflict, no clientid nor owner */
WRITE64((u64)0); /* clientid */
WRITE32(0); /* length of owner name */
@@ -2889,7 +2899,7 @@ nfsd4_encode_lock(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_lo
nfserr = nfsd4_encode_stateid(xdr, &lock->lk_resp_stateid);
else if (nfserr == nfserr_denied)
nfserr = nfsd4_encode_lock_denied(xdr, &lock->lk_denied);
-
+ kfree(lock->lk_denied.ld_owner.data);
return nfserr;
}
--
1.7.9.5
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