From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A5A2241A776; Tue, 21 Jul 2026 19:02:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784660530; cv=none; b=gLpbGeSsY3kT6vSkVf2r6SdFwuILvmWpGtTLTmwvkGGMg2FCeEUxNvjpuTq/hULCm8NPcADSji6whlZM9NioZqw+bSeTiwgXn6ZwHWQ1Huwvipuz6wIAklkKrkJCTj3bT2G3xSaaWWNMKy8ShAQpCZDW5d0Q44TxOabV7C7Xi7Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784660530; c=relaxed/simple; bh=u1BJlP3+TxsLhxigLRWsYJihtO2ti8mjrXVPGx//fro=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sc7fPjY5HA0cxR3upqHFcHpDJ9IZJTo4TGkRqDUgnP4GKplgW+sORf9HCZUpZ+ltXUV6BGUrGxnufod5JMUG13o1UnWMQpFFmuLcgbUKhIJok4xz6KfYX7gBbI5Xf++/vaTsb+4L29bd4ynr0AtTI0kOMMP/60ise2jMxqB+JS4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=cw+D5DxQ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="cw+D5DxQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7706E1F00A3D; Tue, 21 Jul 2026 19:02:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784660526; bh=sD4oSf9unH7iY0pG5Gw9YHjTt2f7AxZSNB7WHooRuOs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=cw+D5DxQj338E5czGF165cAh8NG3jek73LR9dtv4FYbqONx7lK6nhcA6Apfh5OwzH B5V+DMnCR366iSaqEc0DToCbOhWeIlhIejPuJ5eAXykvhOtPPhcGvNdbC+2YbfhK0N +I/8/YlXaDJm3CSxFfQ9dLoj6rON+jqHsJv5eQgE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mike Snitzer , Anna Schumaker , Sasha Levin Subject: [PATCH 7.1 0970/2077] NFSv4/flexfiles: honor FF_FLAGS_NO_IO_THRU_MDS in pg_get_mirror_count_write Date: Tue, 21 Jul 2026 17:10:43 +0200 Message-ID: <20260721152615.700290804@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152552.646164743@linuxfoundation.org> References: <20260721152552.646164743@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mike Snitzer [ Upstream commit 1d62e659c0bf11649cf48e002c2a55d148f2610a ] The FF_FLAGS_NO_IO_THRU_MDS flag lives on each lseg, so any fallback decision made when there is no current lseg (e.g. between LAYOUTRETURN and the next LAYOUTGET) cannot run the per-lseg check. Introduce a sticky hdr-level ditto for FF_FLAGS_NO_IO_THRU_MDS in struct nfs4_flexfile_layout::flags (NFS4_FF_HDR_NO_IO_THRU_MDS bit), set whenever ff_layout_alloc_lseg() parses an lseg with the flag. The bit is never cleared for the lifetime of the layout hdr; the server is assumed to be consistent in its no-fallback policy per file. kzalloc() in ff_layout_alloc_layout_hdr() zero-initializes the field. Use the new ff_layout_hdr_no_fallback_to_mds() helper to gate ff_layout_pg_get_mirror_count_write(): when pnfs_update_layout() returns NULL (e.g. NFS_LAYOUT_BULK_RECALL, pnfs_layout_io_test_failed, pnfs_layoutgets_blocked) the existing code unconditionally calls nfs_pageio_reset_write_mds(). This is a source of unwanted WRITE to MDS. Fix it by checking NFS4_FF_HDR_NO_IO_THRU_MDS bit, and if set surface -EAGAIN instead; the writepage-side caller (nfs_do_writepage() for buffered, nfs_direct_write_reschedule() for O_DIRECT) then redirties the request so writeback retries via pNFS. Fixes: 260074cd8413 ("pNFS/flexfiles: Add support for FF_FLAGS_NO_IO_THRU_MDS") Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Mike Snitzer Signed-off-by: Anna Schumaker Signed-off-by: Sasha Levin --- fs/nfs/flexfilelayout/flexfilelayout.c | 13 +++++++++++++ fs/nfs/flexfilelayout/flexfilelayout.h | 16 ++++++++++++++++ 2 files changed, 29 insertions(+) diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c index 80a3c43aaac052..2e7f857d5a8cb2 100644 --- a/fs/nfs/flexfilelayout/flexfilelayout.c +++ b/fs/nfs/flexfilelayout/flexfilelayout.c @@ -636,6 +636,9 @@ ff_layout_alloc_lseg(struct pnfs_layout_hdr *lh, if (!p) goto out_sort_mirrors; fls->flags = be32_to_cpup(p); + if (fls->flags & FF_FLAGS_NO_IO_THRU_MDS) + set_bit(NFS4_FF_HDR_NO_IO_THRU_MDS, + &FF_LAYOUT_FROM_HDR(lh)->flags); p = xdr_inline_decode(&stream, 4); if (!p) @@ -1185,6 +1188,16 @@ ff_layout_pg_get_mirror_count_write(struct nfs_pageio_descriptor *pgio, 0, NFS4_MAX_UINT64, IOMODE_RW, NFS_I(pgio->pg_inode)->layout, pgio->pg_lseg); + if (NFS_I(pgio->pg_inode)->layout && + ff_layout_hdr_no_fallback_to_mds(NFS_I(pgio->pg_inode)->layout)) { + /* + * FF_FLAGS_NO_IO_THRU_MDS: no current lseg but the server's + * policy forbids MDS fallback. Surface -EAGAIN so writeback + * retries rather than silently issuing the WRITE via MDS. + */ + pgio->pg_error = -EAGAIN; + goto out; + } /* no lseg means that pnfs is not in use, so no mirroring here */ nfs_pageio_reset_write_mds(pgio); out: diff --git a/fs/nfs/flexfilelayout/flexfilelayout.h b/fs/nfs/flexfilelayout/flexfilelayout.h index 17a008c8e97ce9..a5bd00f69e8242 100644 --- a/fs/nfs/flexfilelayout/flexfilelayout.h +++ b/fs/nfs/flexfilelayout/flexfilelayout.h @@ -112,12 +112,16 @@ struct nfs4_ff_layout_segment { struct nfs4_ff_layout_mirror *mirror_array[] __counted_by(mirror_array_cnt); }; +/* nfs4_flexfile_layout::flags bit indices */ +#define NFS4_FF_HDR_NO_IO_THRU_MDS 0 /* any lseg has had FF_FLAGS_NO_IO_THRU_MDS */ + struct nfs4_flexfile_layout { struct pnfs_layout_hdr generic_hdr; struct pnfs_ds_commit_info commit_info; struct list_head mirrors; struct list_head error_list; /* nfs4_ff_layout_ds_err */ ktime_t last_report_time; /* Layoutstat report times */ + unsigned long flags; }; struct nfs4_flexfile_layoutreturn_args { @@ -184,6 +188,18 @@ ff_layout_no_fallback_to_mds(struct pnfs_layout_segment *lseg) return FF_LAYOUT_LSEG(lseg)->flags & FF_FLAGS_NO_IO_THRU_MDS; } +/* + * Sticky hdr-level mirror of FF_FLAGS_NO_IO_THRU_MDS so callers that have + * no current lseg (e.g. between LAYOUTRETURN and the next LAYOUTGET) can + * still honor the no-MDS-fallback policy. + */ +static inline bool +ff_layout_hdr_no_fallback_to_mds(struct pnfs_layout_hdr *lo) +{ + return test_bit(NFS4_FF_HDR_NO_IO_THRU_MDS, + &FF_LAYOUT_FROM_HDR(lo)->flags); +} + static inline bool ff_layout_no_read_on_rw(struct pnfs_layout_segment *lseg) { -- 2.53.0