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 91EC81B0132; Thu, 29 Aug 2024 16:15:58 +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=1724948158; cv=none; b=CZhtpicQWNGmZvQKfmPvu8HjrLuDZusaOp0H9WuA2vdXbSJa1td6JCppyVFt3Ui6tIrmqLstngL4cKsH0z+X8KW7RkOpPvKckVlUUhwnY6s2lt51iwFJZsJw0+vUlejyzcAfKy8On6gXESoLxWwlrss6i6zmp2Ag72Vw/4z5oiE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724948158; c=relaxed/simple; bh=JNe1ki+/vqtDoa5+lYHhEHCq8biuJ2u3Ys7KPm6Xstk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fD1BdfhV8Xla5Sc/EcXCp+s2WsxU5kl+vtzgD+5+6M4hgMwyzu8rc5hmje0krywzDDfsghikzAcsCRHWcACCffqeyKmBpXZ7uWNj8+fw2KYxbClhPD6XxAaZyl/KA9nSAw0SXkh2GgZkFuVt5sizkKlEECY9ppD0GpYhuorc5d0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RzInbD61; 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="RzInbD61" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 39661C4CEC1; Thu, 29 Aug 2024 16:15:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1724948158; bh=JNe1ki+/vqtDoa5+lYHhEHCq8biuJ2u3Ys7KPm6Xstk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=RzInbD61kLd3WJN2Kn+5OrQX9/MDjYToppl5g0eGYbOtjoU2weKeWPpxOmtMw5gyM 0HMc9JE885aKLbtZJprK+HkhVSY2pPQlKOod3dEIB9yv4agVzXTl3gSDtOg5wKE6tP jhG0nOtNvh/kNPXO1uoSRoytEiJfRuSPqNxouKUZn1z0EoALQNVKQMCZlQZGEfAC9U Q0EMFbgTVMEefrMGIaPgvwDxq9boaNGlD1mqPVOintT8w0lfexVUtwTjrQOEPLvHEA R66pxgBHL6SA2o9pWE6MUBKBChvlIgCQ3l447xyU0YOFI50cGgm3NBwqo1dCgIHDhh lyW2KZrKwMMrw== Date: Thu, 29 Aug 2024 12:15:57 -0400 From: Mike Snitzer To: Chuck Lever Cc: linux-nfs@vger.kernel.org, Jeff Layton , Anna Schumaker , Trond Myklebust , NeilBrown , linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v14 16/25] nfsd: add localio support Message-ID: References: <20240829010424.83693-1-snitzer@kernel.org> <20240829010424.83693-17-snitzer@kernel.org> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu, Aug 29, 2024 at 12:01:42PM -0400, Chuck Lever wrote: > On Wed, Aug 28, 2024 at 09:04:11PM -0400, Mike Snitzer wrote: > > From: Weston Andros Adamson > > > > 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. > > > > 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. > > > > 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. > > > > 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. > > > > CONFIG_NFSD_LOCALIO controls the server enablement for localio. > > A later commit will add CONFIG_NFS_LOCALIO to allow the client > > enablement. > > > > 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: > > > > 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). > > > > 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(). > > > > 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. > > > > 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 > > > > 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 > > > > +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 > > > > If unsure, say N. > > > > +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 > > > > 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-$(CONFIG_NFSD_PNFS) += nfs4layouts.o > > nfsd-$(CONFIG_NFSD_BLOCKLAYOUT) += blocklayout.o blocklayoutxdr.o > > nfsd-$(CONFIG_NFSD_SCSILAYOUT) += blocklayout.o blocklayoutxdr.o > > nfsd-$(CONFIG_NFSD_FLEXFILELAYOUT) += flexfilelayout.o flexfilelayoutxdr.o > > +nfsd-$(CONFIG_NFSD_LOCALIO) += 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) > > > > /* 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_LOCALIO) > > > > 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 nfsd_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 and 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_file 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_nfssvc_dom, > > + struct rpc_clnt *rpc_clnt, const struct cred *cred, > > + const struct nfs_fh *nfs_fh, const fmode_t fmode) > > +{ > > + int mayflags = NFSD_MAY_LOCALIO; > > + int status = 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 = nfs_localio_ctx_alloc(); > > + if (!localio) > > + return ERR_PTR(-ENOMEM); > > + > > + /* > > + * Not running in nfsd context, so must safely get reference on nfsd_serv. > > + * But the server may already be shutting down, if so disallow new localio. > > + */ > > + nn = net_generic(cl_nfssvc_net, nfsd_net_id); > > + if (unlikely(!nfsd_serv_try_get(nn))) { > > + status = -ENXIO; > > + goto out_nfsd_serv; > > + } > > + > > + /* nfs_fh -> svc_fh */ > > + fh_init(&fh, NFS4_FHSIZE); > > + fh.fh_handle.fh_size = nfs_fh->size; > > + memcpy(fh.fh_handle.fh_raw, nfs_fh->data, nfs_fh->size); > > + > > + if (fmode & FMODE_READ) > > + mayflags |= NFSD_MAY_READ; > > + if (fmode & FMODE_WRITE) > > + mayflags |= NFSD_MAY_WRITE; > > + > > + svcauth_map_clnt_to_svc_cred_local(rpc_clnt, cred, &rq_cred); > > + > > + beres = nfsd_file_acquire_local(cl_nfssvc_net, &rq_cred, cl_nfssvc_dom, > > + &fh, mayflags, &localio->nf); > > + if (beres) { > > + status = nfs_stat_to_errno(be32_to_cpu(beres)); > > + goto out_fh_put; > > + } > > + localio->nn = 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_typecheck = 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" }) > > > > 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 @@ > > > > #define NFSD_MAY_64BIT_COOKIE 0x1000 /* 64 bit readdir cookies for >= NFSv3 */ > > > > +#define NFSD_MAY_LOCALIO 0x2000 /* for tracing, reflects when localio used */ > > + > > #define NFSD_MAY_CREATE (NFSD_MAY_EXEC|NFSD_MAY_WRITE) > > #define NFSD_MAY_REMOVE (NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC) > > > > @@ -158,6 +160,11 @@ __be32 nfsd_permission(struct svc_cred *cred, struct svc_export *exp, > > > > void nfsd_filp_close(struct file *fp); > > > > +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; > > -- > > 2.44.0 > > > > Acked-by: Chuck Lever > > I think I've looked at all the server-side changes now. I don't see > any issues that block merging this series. OK, thanks! > Two follow-ups: > > I haven't heard an answer to my question about how export options > that translate RPC user IDs might behave for LOCALIO operations > (eg. root_squash, all_squash). Test results, design points, > NEEDS_WORK, etc. > > Someone should try out the trace points that we neutered in > fh_verify() before this set gets applied. I'll work on both as a prereq for posting the final.