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 439EB1B3B39; Thu, 29 Aug 2024 16:49:24 +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=1724950165; cv=none; b=nLHyRjo5HVuS6yG2srPODeg9kxIR2yPtzKw3Nvx79BWqL9uMTTxAokzR7Be7eHQZQfB/WyYgWTNxSSaucqa7/km8hH5v7wg9TSHBItr2lcXyHfRGDMz+c0HBLh8i8sGIk72ReuUgClolPqiKelRhOIdfe/MpIIsRakSVYhmjqc8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724950165; c=relaxed/simple; bh=DI3wG2LXaYGvWnzwxAX1FCXXpTijGT2kAuzO9cEBPw8=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=GtyaKBL6Ykp9YopKgu0sSXaC15YSAvA3Ncdh1vCRiyZjQM1J32oxGWy0FK0WqLyEfdKDlilbCGOUkqJAo/9NmTVoJPXgOCQvsBYZp1bYWPwyaTuBM/OA9ljZ1f9VAHX22Wps5TZJmz0DnMmWwCIFV3wOLdC83KqGsNrVERIRQ6E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lq64UJzR; 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="lq64UJzR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3018AC4CEC1; Thu, 29 Aug 2024 16:49:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1724950164; bh=DI3wG2LXaYGvWnzwxAX1FCXXpTijGT2kAuzO9cEBPw8=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=lq64UJzRWcLp2vEROpX4GwYrRRWSSNOW/lrZ1Zp2GahtnBTU9eqzT1yQMa8glFqfW 2x5MSXLebdxgv0eU67ItiB73h31DwYwcuuExDmQSqT/g6E5iFS0VtaoanPcu+BCVh4 aZSjQ197pYyHnLvf6YPktxMTLPhfvn0DSnoa7gQlLbFaJJbko6mshYTwou/3Okm5h+ N1IiLBtedG0GX3C1HaqchGqcTB2TtQM2LNae6og4bNtrfqi5tQuqqdj+O6p0pnVlVE IKtwmHzf7Mu0YlAfBl3t8zLhYkVfIxMiagdWX0RBxHs8m24BQmnBboRZfhogdcBdEg SETehyMa1yxhw== Message-ID: <30842ebcf33e97f2f9af8eb57b2eeaec05e7dea6.camel@kernel.org> Subject: Re: [PATCH v14 16/25] nfsd: add localio support From: Jeff Layton To: Mike Snitzer , linux-nfs@vger.kernel.org Cc: Chuck Lever , Anna Schumaker , Trond Myklebust , NeilBrown , linux-fsdevel@vger.kernel.org Date: Thu, 29 Aug 2024 12:49:23 -0400 In-Reply-To: <20240829010424.83693-17-snitzer@kernel.org> References: <20240829010424.83693-1-snitzer@kernel.org> <20240829010424.83693-17-snitzer@kernel.org> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV 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Wed, 2024-08-28 at 21:04 -0400, Mike Snitzer wrote: > From: Weston Andros Adamson >=20 > Add server support for bypassing NFS for localhost reads, writes, and > commits. This is only useful when both the client and server are > running on the same host. >=20 > If nfsd_open_local_fh() fails then the NFS client will both retry and > fallback to normal network-based read, write and commit operations if > localio is no longer supported. >=20 > Care is taken to ensure the same NFS security mechanisms are used > (authentication, etc) regardless of whether localio or regular NFS > access is used. The auth_domain established as part of the traditional > NFS client access to the NFS server is also used for localio. Store > auth_domain for localio in nfsd_uuid_t and transfer it to the client > if it is local to the server. >=20 > Relative to containers, localio gives the client access to the network > namespace the server has. This is required to allow the client to > access the server's per-namespace nfsd_net struct. >=20 > CONFIG_NFSD_LOCALIO controls the server enablement for localio. > A later commit will add CONFIG_NFS_LOCALIO to allow the client > enablement. Do we need separate CONFIG options? Surely if you have one, you'll always want the other. >=20 > This commit also introduces the use of nfsd's percpu_ref to interlock > nfsd_destroy_serv and nfsd_open_local_fh, to ensure nn->nfsd_serv is > not destroyed while in use by nfsd_open_local_fh, and warrants a more > detailed explanation: >=20 > nfsd_open_local_fh uses nfsd_serv_try_get before opening its file > handle and then the reference must be dropped by the caller using > nfsd_serv_put (via nfs_localio_ctx_free). >=20 > This "interlock" working relies heavily on nfsd_open_local_fh()'s > maybe_get_net() safely dealing with the possibility that the struct > net (and nfsd_net by association) may have been destroyed by > nfsd_destroy_serv() via nfsd_shutdown_net(). >=20 > Verified to fix an easy to hit crash that would occur if an nfsd > instance running in a container, with a localio client mounted, is > shutdown. Upon restart of the container and associated nfsd the client > would go on to crash due to NULL pointer dereference that occuured due > to the nfs client's localio attempting to nfsd_open_local_fh(), using > nn->nfsd_serv, without having a proper reference on nn->nfsd_serv. >=20 Maybe transplant a version of the above 4 paragraphs to the patch that adds the percpu_ref handling? > Signed-off-by: Weston Andros Adamson > Signed-off-by: Trond Myklebust > Co-developed-by: Mike Snitzer > Signed-off-by: Mike Snitzer > --- > fs/Kconfig | 3 ++ > fs/nfsd/Kconfig | 16 +++++++ > fs/nfsd/Makefile | 1 + > fs/nfsd/filecache.c | 2 +- > fs/nfsd/localio.c | 105 ++++++++++++++++++++++++++++++++++++++++++++ > fs/nfsd/trace.h | 3 +- > fs/nfsd/vfs.h | 7 +++ > 7 files changed, 135 insertions(+), 2 deletions(-) > create mode 100644 fs/nfsd/localio.c >=20 > diff --git a/fs/Kconfig b/fs/Kconfig > index a46b0cbc4d8f..1b8a5edbddff 100644 > --- a/fs/Kconfig > +++ b/fs/Kconfig > @@ -377,6 +377,9 @@ config NFS_ACL_SUPPORT > tristate > select FS_POSIX_ACL > =20 > +config NFS_COMMON_LOCALIO_SUPPORT > + bool > + > config NFS_COMMON > bool > depends on NFSD || NFS_FS || LOCKD > diff --git a/fs/nfsd/Kconfig b/fs/nfsd/Kconfig > index c0bd1509ccd4..e6fa7eaa1db0 100644 > --- a/fs/nfsd/Kconfig > +++ b/fs/nfsd/Kconfig > @@ -90,6 +90,22 @@ config NFSD_V4 > =20 > If unsure, say N. > =20 > +config NFSD_LOCALIO > + bool "NFS server support for the LOCALIO auxiliary protocol" > + depends on NFSD > + select NFS_COMMON_LOCALIO_SUPPORT > + default n > + help > + Some NFS servers support an auxiliary NFS LOCALIO protocol > + that is not an official part of the NFS protocol. > + > + This option enables support for the LOCALIO protocol in the > + kernel's NFS server. Enable this to permit local NFS clients > + to bypass the network when issuing reads and writes to the > + local NFS server. > + > + If unsure, say N. > + > config NFSD_PNFS > bool > =20 > diff --git a/fs/nfsd/Makefile b/fs/nfsd/Makefile > index b8736a82e57c..78b421778a79 100644 > --- a/fs/nfsd/Makefile > +++ b/fs/nfsd/Makefile > @@ -23,3 +23,4 @@ nfsd-$(CONFIG_NFSD_PNFS) +=3D nfs4layouts.o > nfsd-$(CONFIG_NFSD_BLOCKLAYOUT) +=3D blocklayout.o blocklayoutxdr.o > nfsd-$(CONFIG_NFSD_SCSILAYOUT) +=3D blocklayout.o blocklayoutxdr.o > nfsd-$(CONFIG_NFSD_FLEXFILELAYOUT) +=3D flexfilelayout.o flexfilelayoutx= dr.o > +nfsd-$(CONFIG_NFSD_LOCALIO) +=3D localio.o > diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c > index a83d469bca6b..49f4aab3208a 100644 > --- a/fs/nfsd/filecache.c > +++ b/fs/nfsd/filecache.c > @@ -53,7 +53,7 @@ > #define NFSD_FILE_CACHE_UP (0) > =20 > /* We only care about NFSD_MAY_READ/WRITE for this cache */ > -#define NFSD_FILE_MAY_MASK (NFSD_MAY_READ|NFSD_MAY_WRITE) > +#define NFSD_FILE_MAY_MASK (NFSD_MAY_READ|NFSD_MAY_WRITE|NFSD_MAY_LOCALI= O) > =20 > static DEFINE_PER_CPU(unsigned long, nfsd_file_cache_hits); > static DEFINE_PER_CPU(unsigned long, nfsd_file_acquisitions); > diff --git a/fs/nfsd/localio.c b/fs/nfsd/localio.c > new file mode 100644 > index 000000000000..4b65c66be129 > --- /dev/null > +++ b/fs/nfsd/localio.c > @@ -0,0 +1,105 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * NFS server support for local clients to bypass network stack > + * > + * Copyright (C) 2014 Weston Andros Adamson > + * Copyright (C) 2019 Trond Myklebust > + * Copyright (C) 2024 Mike Snitzer > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include "nfsd.h" > +#include "vfs.h" > +#include "netns.h" > +#include "filecache.h" > + > +/** > + * nfsd_open_local_fh - lookup a local filehandle @nfs_fh and map to nfs= d_file > + * > + * @cl_nfssvc_net: the 'struct net' to use to get the proper nfsd_net > + * @cl_nfssvc_dom: the 'struct auth_domain' required for localio access > + * @rpc_clnt: rpc_clnt that the client established, used for sockaddr an= d cred > + * @cred: cred that the client established > + * @nfs_fh: filehandle to lookup > + * @fmode: fmode_t to use for open > + * > + * This function maps a local fh to a path on a local filesystem. > + * This is useful when the nfs client has the local server mounted - it = can > + * avoid all the NFS overhead with reads, writes and commits. > + * > + * On successful return, returned nfs_localio_ctx will have its nfsd_fil= e and > + * nfsd_net members set. Caller is responsible for calling nfsd_file_put= and > + * nfsd_serv_put (via nfs_localio_ctx_free). > + */ > +struct nfs_localio_ctx * > +nfsd_open_local_fh(struct net *cl_nfssvc_net, struct auth_domain *cl_nfs= svc_dom, > + struct rpc_clnt *rpc_clnt, const struct cred *cred, > + const struct nfs_fh *nfs_fh, const fmode_t fmode) > +{ > + int mayflags =3D NFSD_MAY_LOCALIO; > + int status =3D 0; > + struct nfsd_net *nn; > + struct svc_cred rq_cred; > + struct svc_fh fh; > + struct nfs_localio_ctx *localio; > + __be32 beres; > + > + if (nfs_fh->size > NFS4_FHSIZE) > + return ERR_PTR(-EINVAL); > + > + localio =3D nfs_localio_ctx_alloc(); > + if (!localio) > + return ERR_PTR(-ENOMEM); > + > + /* > + * Not running in nfsd context, so must safely get reference on nfsd_se= rv. > + * But the server may already be shutting down, if so disallow new loca= lio. > + */ > + nn =3D net_generic(cl_nfssvc_net, nfsd_net_id); > + if (unlikely(!nfsd_serv_try_get(nn))) { > + status =3D -ENXIO; > + goto out_nfsd_serv; > + } > + > + /* nfs_fh -> svc_fh */ > + fh_init(&fh, NFS4_FHSIZE); > + fh.fh_handle.fh_size =3D nfs_fh->size; > + memcpy(fh.fh_handle.fh_raw, nfs_fh->data, nfs_fh->size); > + > + if (fmode & FMODE_READ) > + mayflags |=3D NFSD_MAY_READ; > + if (fmode & FMODE_WRITE) > + mayflags |=3D NFSD_MAY_WRITE; > + > + svcauth_map_clnt_to_svc_cred_local(rpc_clnt, cred, &rq_cred); > + > + beres =3D nfsd_file_acquire_local(cl_nfssvc_net, &rq_cred, cl_nfssvc_do= m, > + &fh, mayflags, &localio->nf); > + if (beres) { > + status =3D nfs_stat_to_errno(be32_to_cpu(beres)); > + goto out_fh_put; > + } > + localio->nn =3D nn; > + > +out_fh_put: > + fh_put(&fh); > + if (rq_cred.cr_group_info) > + put_group_info(rq_cred.cr_group_info); > +out_nfsd_serv: > + if (status) { > + nfs_localio_ctx_free(localio); > + return ERR_PTR(status); > + } > + return localio; > +} > +EXPORT_SYMBOL_GPL(nfsd_open_local_fh); > + > +/* Compile time type checking, not used by anything */ > +static nfs_to_nfsd_open_local_fh_t __maybe_unused nfsd_open_local_fh_typ= echeck =3D nfsd_open_local_fh; > diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h > index d22027e23761..82bcefcd1f21 100644 > --- a/fs/nfsd/trace.h > +++ b/fs/nfsd/trace.h > @@ -86,7 +86,8 @@ DEFINE_NFSD_XDR_ERR_EVENT(cant_encode); > { NFSD_MAY_NOT_BREAK_LEASE, "NOT_BREAK_LEASE" }, \ > { NFSD_MAY_BYPASS_GSS, "BYPASS_GSS" }, \ > { NFSD_MAY_READ_IF_EXEC, "READ_IF_EXEC" }, \ > - { NFSD_MAY_64BIT_COOKIE, "64BIT_COOKIE" }) > + { NFSD_MAY_64BIT_COOKIE, "64BIT_COOKIE" }, \ > + { NFSD_MAY_LOCALIO, "LOCALIO" }) > =20 > TRACE_EVENT(nfsd_compound, > TP_PROTO( > diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h > index 01947561d375..e12310dd5f4c 100644 > --- a/fs/nfsd/vfs.h > +++ b/fs/nfsd/vfs.h > @@ -33,6 +33,8 @@ > =20 > #define NFSD_MAY_64BIT_COOKIE 0x1000 /* 64 bit readdir cookies for >=3D= NFSv3 */ > =20 > +#define NFSD_MAY_LOCALIO 0x2000 /* for tracing, reflects when localio u= sed */ > + > #define NFSD_MAY_CREATE (NFSD_MAY_EXEC|NFSD_MAY_WRITE) > #define NFSD_MAY_REMOVE (NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC) > =20 > @@ -158,6 +160,11 @@ __be32 nfsd_permission(struct svc_cred *cred, struc= t svc_export *exp, > =20 > void nfsd_filp_close(struct file *fp); > =20 > +struct nfs_localio_ctx * > +nfsd_open_local_fh(struct net *, struct auth_domain *, > + struct rpc_clnt *, const struct cred *, > + const struct nfs_fh *, const fmode_t); > + > static inline int fh_want_write(struct svc_fh *fh) > { > int ret; Reviewed-by: Jeff Layton