[PATCH v2 0/1] NFSv4.1: Apply session size limits on clone path

Tushar Sariya
2026-04-04T14:28:39Z

From: Tushar Sariya <tushar.97@hotmail.com>

The NFS automount clone path (nfs4_clone_server) is missing the
session-size clamping that top-level mounts get in
nfs4_server_common_setup(). This was exposed by 2b092175f5e3 which
changed submounts to no longer unconditionally inherit the parent's
already-clamped rsize/wsize. On servers that enforce tight
max_request_size budgets (reported on Dell EMC Isilon/OneFS), the
child mount ends up with raw unclamped values that exceed the session
channel limits, resulting in NFS4ERR_REQ_TOO_BIG and user-visible EIO.

Note: I was unable to reproduce the exact failure locally as it appears
to require a server that enforces tight max_request_size budgets. The
fix is based on code analysis — the clone path is missing the same
session-limit clamping that top-level mounts apply in
nfs4_server_common_setup(). Tested that the kernel builds and boots
successfully.

Tushar Sariya (1):
NFSv4.1: Apply session size limits on clone path

fs/nfs/internal.h | 2 ++
fs/nfs/nfs4client.c | 4 ++--
fs/nfs/nfs4proc.c | 3 +++
3 files changed, 7 insertions(+), 2 deletions(-)

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2.43.0