From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 65630426EB4; Tue, 31 Mar 2026 17:52:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774979533; cv=none; b=VtU/K7idzv2CfjmEmAdiz6cysggX4/oItAKxMhrwNZLpnZiNaq/7/hQ3Orme1/P1JcAb585MTpYdYvjqVL/VU1n444GnBJcTNN1Fgea0V2h/UMlSxz1ibGPDLoWuyymicTij10MuyvSu4hmYATTlqZe6EltxCCFTuyRfPF5fiwc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774979533; c=relaxed/simple; bh=XHS9GYl6jWMS8N92t7nfRJKFs8QPMUWOJq9AgTUJtvI=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=ive4pb5fYsJQMqSwTCWslCfZWrFmlhrAhPOIR2/wx93AqnBf5SlnuJLLtljLNVsmfQHfPInaS/4YtdNV+Qfx/uRyGMyg9rRY0yGioiAtBWKiMCVRGz/F5EYduvoRI70Z6av/UzqwykmzGZ3Mgy2Bol52VZu4o0dNyZtVMQhKSYs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FcK8l+a5; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="FcK8l+a5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DFAB2C19423; Tue, 31 Mar 2026 17:52:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774979532; bh=XHS9GYl6jWMS8N92t7nfRJKFs8QPMUWOJq9AgTUJtvI=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=FcK8l+a5Badu77ALoGBbaQAYdXA1RlTqndy+I9V2BgyujEpgKgsKLfDkjqhvq8ysl Ti3bqoc9uYSy7oMY/3MBYago8ImcpNX5BKJcay8pwWkfwpHTPcAaNSI45eyU3OlpNe +KYCcJu3btjt6pLNXXL965Nz1XzsCWqnY2ELs7vgliPdTNne6wQ9UOndlDbHF+O4Z9 7VrhIsnYxQPDwGjVRt8POgZl4l441WxozW5C6kxefKTibfnItmvHXiFuf6JDQLy17D qSVxjfpGzl3YZs2jN80M0dlN1AjuU+XG4DkqHG5JbGXoEpvmNnpoa2GNxgnpqKGIkk 9+xEyx9MyNPsw== Message-ID: <73abf22dec079ed8eb3795ecdeaa851b704bdcb8.camel@kernel.org> Subject: Re: [PATCH 4/4] exportfs,nfsd: rework checking for layout-based block device access support From: Jeff Layton To: Christoph Hellwig , Chuck Lever , Amir Goldstein Cc: NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey , linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Date: Tue, 31 Mar 2026 13:52:09 -0400 In-Reply-To: <20260331153406.4049290-5-hch@lst.de> References: <20260331153406.4049290-1-hch@lst.de> <20260331153406.4049290-5-hch@lst.de> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV 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Tue, 2026-03-31 at 17:33 +0200, Christoph Hellwig wrote: > Currently NFSD hard codes checking support for block-style layouts. > Lift the checks into a file system-helper and provide a exportfs-level > helper to implement the typical checks. >=20 > This prepares for supporting block layout export of multiple devices > per file system. >=20 > Signed-off-by: Christoph Hellwig > --- > fs/nfsd/export.c | 3 +- > fs/nfsd/nfs4layouts.c | 26 +++++------------ > fs/xfs/xfs_pnfs.c | 13 +++++++++ > include/linux/exportfs_block.h | 52 +++++++++++++++++++++++++++++++++- > 4 files changed, 73 insertions(+), 21 deletions(-) >=20 > diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c > index 8e8a76a44ff0..e20298f9212f 100644 > --- a/fs/nfsd/export.c > +++ b/fs/nfsd/export.c > @@ -735,7 +735,8 @@ static int svc_export_parse(struct cache_detail *cd, = char *mesg, int mlen) > goto out4; > err =3D 0; > =20 > - nfsd4_setup_layout_type(&exp); > + if (exp.ex_flags & NFSEXP_PNFS) > + nfsd4_setup_layout_type(&exp); > } > =20 > expp =3D svc_export_lookup(&exp); > diff --git a/fs/nfsd/nfs4layouts.c b/fs/nfsd/nfs4layouts.c > index c53eb67969eb..7b849b637b5e 100644 > --- a/fs/nfsd/nfs4layouts.c > +++ b/fs/nfsd/nfs4layouts.c > @@ -2,7 +2,6 @@ > /* > * Copyright (c) 2014 Christoph Hellwig. > */ > -#include > #include > #include > #include > @@ -126,28 +125,17 @@ nfsd4_set_deviceid(struct nfsd4_deviceid *id, const= struct svc_fh *fhp, > =20 > void nfsd4_setup_layout_type(struct svc_export *exp) > { > -#if defined(CONFIG_NFSD_BLOCKLAYOUT) || defined(CONFIG_NFSD_SCSILAYOUT) > struct super_block *sb =3D exp->ex_path.mnt->mnt_sb; > - struct exportfs_block_ops *bops =3D sb->s_export_op->block_ops; > -#endif > - > - if (!(exp->ex_flags & NFSEXP_PNFS)) > - return; > + expfs_block_layouts_t block_supported =3D exporfs_layouts_supported(sb)= ; > =20 > -#ifdef CONFIG_NFSD_FLEXFILELAYOUT > - exp->ex_layout_types |=3D 1 << LAYOUT_FLEX_FILES; > -#endif > -#ifdef CONFIG_NFSD_BLOCKLAYOUT > - if (bops && bops->get_uuid && bops->map_blocks && bops->commit_blocks) > + if (IS_ENABLED(CONFIG_NFSD_FLEXFILELAYOUT)) > + exp->ex_layout_types |=3D 1 << LAYOUT_FLEX_FILES; > + if (IS_ENABLED(CONFIG_NFSD_BLOCKLAYOUT) && > + (block_supported & EXPFS_BLOCK_IN_BAND_ID)) > exp->ex_layout_types |=3D 1 << LAYOUT_BLOCK_VOLUME; > -#endif > -#ifdef CONFIG_NFSD_SCSILAYOUT > - if (bops && bops->map_blocks && bops->commit_blocks && > - sb->s_bdev && > - sb->s_bdev->bd_disk->fops->pr_ops && > - sb->s_bdev->bd_disk->fops->get_unique_id) > + if (IS_ENABLED(CONFIG_NFSD_SCSILAYOUT) && > + (block_supported & EXPFS_BLOCK_OUT_OF_BAND_ID)) > exp->ex_layout_types |=3D 1 << LAYOUT_SCSI; > -#endif > } > =20 > void nfsd4_close_layout(struct nfs4_layout_stateid *ls) > diff --git a/fs/xfs/xfs_pnfs.c b/fs/xfs/xfs_pnfs.c > index fee782a3edbe..acefa0b99f53 100644 > --- a/fs/xfs/xfs_pnfs.c > +++ b/fs/xfs/xfs_pnfs.c > @@ -13,6 +13,7 @@ > #include "xfs_bmap.h" > #include "xfs_iomap.h" > #include "xfs_pnfs.h" > +#include > =20 > /* > * Ensure that we do not have any outstanding pNFS layouts that can be u= sed by > @@ -45,6 +46,17 @@ xfs_break_leased_layouts( > return error; > } > =20 > +static expfs_block_layouts_t > +xfs_fs_layouts_supported( > + struct super_block *sb) > +{ > + expfs_block_layouts_t supported =3D EXPFS_BLOCK_IN_BAND_ID; > + > + if (exportfs_bdev_supports_out_of_band_id(sb->s_bdev)) > + supported |=3D EXPFS_BLOCK_OUT_OF_BAND_ID; > + return supported; > +} > + > /* > * Get a unique ID including its location so that the client can identif= y > * the exported device. > @@ -335,6 +347,7 @@ xfs_fs_commit_blocks( > } > =20 > struct exportfs_block_ops xfs_export_block_ops =3D { > + .layouts_supported =3D xfs_fs_layouts_supported, > .get_uuid =3D xfs_fs_get_uuid, > .map_blocks =3D xfs_fs_map_blocks, > .commit_blocks =3D xfs_fs_commit_blocks, > diff --git a/include/linux/exportfs_block.h b/include/linux/exportfs_bloc= k.h > index d1dec4689b14..8d5b0b0c5a82 100644 > --- a/include/linux/exportfs_block.h > +++ b/include/linux/exportfs_block.h > @@ -7,13 +7,35 @@ > #ifndef LINUX_EXPORTFS_BLOCK_H > #define LINUX_EXPORTFS_BLOCK_H 1 > =20 > -#include > +#include > +#include > +#include > =20 > struct inode; > struct iomap; > struct super_block; > =20 > +/* > + * There are the two types of block-style layout support: > + * - In-band implies a device identified by a unique cookie inside the = actual > + * device address space checked by the ->get_uuid method as used by t= he pNFS > + * block layout. This is a bit dangerous and deprecated. > + * - Out of band implies identification by out of band unique identifie= rs > + * specified by the storage protocol, which is much safer and used by= the > + * pNFS SCSI/NVMe layouts. > + */ > +typedef unsigned int __bitwise expfs_block_layouts_t; > +#define EXPFS_BLOCK_FLAG(__bit) \ > + ((__force expfs_block_layouts_t)(1u << __bit)) > +#define EXPFS_BLOCK_IN_BAND_ID EXPFS_BLOCK_FLAG(0) > +#define EXPFS_BLOCK_OUT_OF_BAND_ID EXPFS_BLOCK_FLAG(1) > + > struct exportfs_block_ops { > + /* > + * Returns the EXPFS_BLOCK_* bitmap of supported layout types. > + */ > + expfs_block_layouts_t (*layouts_supported)(struct super_block *sb); > + > /* > * Get the in-band device unique signature exposed to clients. > */ > @@ -35,4 +57,32 @@ struct exportfs_block_ops { > int nr_iomaps, loff_t new_size); > }; > =20 > +static inline bool > +exportfs_bdev_supports_out_of_band_id(struct block_device *bdev) > +{ > + return bdev->bd_disk->fops->pr_ops && > + bdev->bd_disk->fops->get_unique_id; > +} > + > +#ifdef CONFIG_EXPORTFS_BLOCK_OPS > +static inline expfs_block_layouts_t > +exporfs_layouts_supported(struct super_block *sb) > +{ > + struct exportfs_block_ops *bops =3D sb->s_export_op->block_ops; > + > + if (!bops || > + !bops->layouts_supported || > + WARN_ON_ONCE(!bops->map_blocks) || > + WARN_ON_ONCE(!bops->commit_blocks)) > + return 0; > + return bops->layouts_supported(sb); > +} > +#else > +static inline expfs_block_layouts_t > +exporfs_layouts_supported(struct super_block *sb) > +{ > + return 0; > +} > +#endif /* CONFIG_EXPORTFS_BLOCK_OPS */ > + > #endif /* LINUX_EXPORTFS_BLOCK_H */ Much cleaner. Reviewed-by: Jeff Layton