Re: [PATCH] nfsd: reset write verifier on deferred writeback errors

[Chuck Lever]

From: Chuck Lever <chuck.lever@xxxxxxxxxx>

On Fri, 22 May 2026 12:44:19 -0400, Jeff Layton wrote:
> nfsd_vfs_write() and nfsd_commit() both call filemap_check_wb_err() to
> detect deferred writeback errors, but neither rotates the server's write
> verifier (nn->writeverf) when this check fails. Every other
> durable-storage-failure path in these functions calls
> commit_reset_write_verifier() before returning an error.
> 
> The missing rotation means clients holding UNSTABLE write data under the
> current verifier will COMMIT, receive the unchanged verifier back, and
> conclude their data is durable — silently dropping data that failed
> writeback. This violates the UNSTABLE+COMMIT durability contract
> (RFC 1813 §3.3.7, RFC 8881 §18.32).
> 
> [...]

Applied to nfsd-testing, thanks!

[1/1] nfsd: reset write verifier on deferred writeback errors
      commit: f8cf3c1c418ef04947bc16e4a2ef8074452de593

--
Chuck Lever <chuck.lever@xxxxxxxxxx>