| Message ID | 20240823181423.20458-11-snitzer@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | nfs/nfsd: add support for localio | expand |
On Fri, Aug 23, 2024 at 02:14:08PM -0400, Mike Snitzer wrote: > From: Weston Andros Adamson <dros@primarydata.com> > > 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 a percpu_ref to interlock > nfsd_destroy_serv and nfsd_open_local_fh, and warrants a more > detailed explanation: > > Introduce nfsd_serv_try_get and nfsd_serv_put and update the nfsd code > to prevent nfsd_destroy_serv from destroying nn->nfsd_serv until any > client initiated localio calls to nfsd (that are _not_ in the context > of nfsd) are complete. > > nfsd_open_local_fh is updated to nfsd_serv_try_get before opening its > file handle and then drop the reference using nfsd_serv_put at the end > of nfsd_open_local_fh. > > 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 <dros@primarydata.com> > Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> > Co-developed-by: Mike Snitzer <snitzer@kernel.org> > Signed-off-by: Mike Snitzer <snitzer@kernel.org> > --- > fs/Kconfig | 3 ++ > fs/nfsd/Kconfig | 14 ++++++ > fs/nfsd/Makefile | 1 + > fs/nfsd/filecache.c | 2 +- > fs/nfsd/localio.c | 108 ++++++++++++++++++++++++++++++++++++++++++++ > fs/nfsd/netns.h | 8 +++- > fs/nfsd/nfssvc.c | 39 ++++++++++++++++ > fs/nfsd/trace.h | 3 +- > fs/nfsd/vfs.h | 10 ++++ > 9 files changed, 185 insertions(+), 3 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..1fca57c79c60 100644 > --- a/fs/nfsd/Kconfig > +++ b/fs/nfsd/Kconfig > @@ -90,6 +90,20 @@ 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 Because this is a new and experimental facility that is still under development, CONFIG_NFSD_LOCALIO should 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 bypass using the NFS > + protocol when issuing reads, writes and commits to the server. I found the last sentence in this paragraph confusing. Consider instead: “Enable this to permit local NFS clients to bypass the network when issuing reads and write 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 2a79c45ca27a..d7c6122231f4 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..8e0cce835f81 > --- /dev/null > +++ b/fs/nfsd/localio.c > @@ -0,0 +1,108 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * NFS server support for local clients to bypass network stack > + * > + * Copyright (C) 2014 Weston Andros Adamson <dros@primarydata.com> > + * Copyright (C) 2019 Trond Myklebust <trond.myklebust@hammerspace.com> > + * Copyright (C) 2024 Mike Snitzer <snitzer@hammerspace.com> > + */ > + > +#include <linux/exportfs.h> > +#include <linux/sunrpc/svcauth_gss.h> > +#include <linux/sunrpc/clnt.h> > +#include <linux/nfs.h> > +#include <linux/nfs_common.h> > +#include <linux/nfslocalio.h> > +#include <linux/string.h> > + > +#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 @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 > + * @pnf: returned nfsd_file pointer that maps to @nfs_fh > + * > + * 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, caller is responsible for calling nfsd_file_put. Also > + * note that this is called from nfs.ko via find_symbol() to avoid an explicit > + * dependency on knfsd. So, there is no forward declaration in a header file > + * for it that is shared with the client. > + */ > +int 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, > + struct nfsd_file **pnf) > +{ > + int mayflags = NFSD_MAY_LOCALIO; > + int status = 0; > + struct nfsd_net *nn; > + const struct cred *save_cred; > + struct svc_cred rq_cred; > + struct svc_fh fh; > + __be32 beres; > + > + if (nfs_fh->size > NFS4_FHSIZE) > + return -EINVAL; > + > + /* Not running in nfsd context, must safely get reference on nfsd_serv */ > + cl_nfssvc_net = maybe_get_net(cl_nfssvc_net); > + if (!cl_nfssvc_net) > + return -ENXIO; > + nn = net_generic(cl_nfssvc_net, nfsd_net_id); > + > + /* The server may already be shutting down, disallow new localio */ > + if (unlikely(!nfsd_serv_try_get(nn))) { > + status = -ENXIO; > + goto out_net; > + } > + > + /* Save client creds before calling nfsd_file_acquire_local which calls nfsd_setuser */ > + save_cred = get_current_cred(); > + > + /* 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; > + > + rpcauth_map_clnt_to_svc_cred_local(rpc_clnt, cred, &rq_cred); > + > + beres = nfsd_file_acquire_local(cl_nfssvc_net, &rq_cred, rpc_clnt->cl_vers, > + cl_nfssvc_dom, &fh, mayflags, pnf); > + if (beres) { > + status = nfs_stat_to_errno(be32_to_cpu(beres)); > + goto out_fh_put; > + } > +out_fh_put: > + fh_put(&fh); > + if (rq_cred.cr_group_info) > + put_group_info(rq_cred.cr_group_info); > + revert_creds(save_cred); > + nfsd_serv_put(nn); > +out_net: > + put_net(cl_nfssvc_net); > + return status; > +} > +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/netns.h b/fs/nfsd/netns.h > index 238fc4e56e53..e2d953f21dde 100644 > --- a/fs/nfsd/netns.h > +++ b/fs/nfsd/netns.h > @@ -13,6 +13,7 @@ > #include <linux/filelock.h> > #include <linux/nfs4.h> > #include <linux/percpu_counter.h> > +#include <linux/percpu-refcount.h> > #include <linux/siphash.h> > #include <linux/sunrpc/stats.h> > > @@ -139,7 +140,9 @@ struct nfsd_net { > > struct svc_info nfsd_info; > #define nfsd_serv nfsd_info.serv > - > + struct percpu_ref nfsd_serv_ref; > + struct completion nfsd_serv_confirm_done; > + struct completion nfsd_serv_free_done; > > /* > * clientid and stateid data for construction of net unique COPY > @@ -221,6 +224,9 @@ struct nfsd_net { > extern bool nfsd_support_version(int vers); > extern unsigned int nfsd_net_id; > > +bool nfsd_serv_try_get(struct nfsd_net *nn); > +void nfsd_serv_put(struct nfsd_net *nn); > + > void nfsd_copy_write_verifier(__be32 verf[2], struct nfsd_net *nn); > void nfsd_reset_write_verifier(struct nfsd_net *nn); > #endif /* __NFSD_NETNS_H__ */ > diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c > index b02eaaea7d62..c639fbe4d8c2 100644 > --- a/fs/nfsd/nfssvc.c > +++ b/fs/nfsd/nfssvc.c > @@ -192,6 +192,30 @@ int nfsd_minorversion(struct nfsd_net *nn, u32 minorversion, enum vers_op change > return 0; > } > > +bool nfsd_serv_try_get(struct nfsd_net *nn) > +{ > + return percpu_ref_tryget_live(&nn->nfsd_serv_ref); > +} > + > +void nfsd_serv_put(struct nfsd_net *nn) > +{ > + percpu_ref_put(&nn->nfsd_serv_ref); > +} > + > +static void nfsd_serv_done(struct percpu_ref *ref) > +{ > + struct nfsd_net *nn = container_of(ref, struct nfsd_net, nfsd_serv_ref); > + > + complete(&nn->nfsd_serv_confirm_done); > +} > + > +static void nfsd_serv_free(struct percpu_ref *ref) > +{ > + struct nfsd_net *nn = container_of(ref, struct nfsd_net, nfsd_serv_ref); > + > + complete(&nn->nfsd_serv_free_done); > +} > + Neil set a good precedent here: Perhaps nfsd_serv_try_get() and friends should be added as a separate patch with a patch description that explains their purpose and operation > /* > * Maximum number of nfsd processes > */ > @@ -391,6 +415,7 @@ static void nfsd_shutdown_net(struct net *net) > lockd_down(net); > nn->lockd_up = false; > } > + percpu_ref_exit(&nn->nfsd_serv_ref); > nn->nfsd_net_up = false; > nfsd_shutdown_generic(); > } > @@ -470,6 +495,13 @@ void nfsd_destroy_serv(struct net *net) > struct nfsd_net *nn = net_generic(net, nfsd_net_id); > struct svc_serv *serv = nn->nfsd_serv; > > + lockdep_assert_held(&nfsd_mutex); > + > + percpu_ref_kill_and_confirm(&nn->nfsd_serv_ref, nfsd_serv_done); > + wait_for_completion(&nn->nfsd_serv_confirm_done); > + wait_for_completion(&nn->nfsd_serv_free_done); > + /* percpu_ref_exit is called in nfsd_shutdown_net */ > + > spin_lock(&nfsd_notifier_lock); > nn->nfsd_serv = NULL; > spin_unlock(&nfsd_notifier_lock); > @@ -594,6 +626,13 @@ int nfsd_create_serv(struct net *net) > if (nn->nfsd_serv) > return 0; > > + error = percpu_ref_init(&nn->nfsd_serv_ref, nfsd_serv_free, > + 0, GFP_KERNEL); > + if (error) > + return error; > + init_completion(&nn->nfsd_serv_free_done); > + init_completion(&nn->nfsd_serv_confirm_done); > + > if (nfsd_max_blksize == 0) > nfsd_max_blksize = nfsd_get_default_max_blksize(); > nfsd_reset_versions(nn); > diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h > index 77bbd23aa150..9c0610fdd11c 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..ec8a8aae540b 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 +160,14 @@ __be32 nfsd_permission(struct svc_cred *cred, struct svc_export *exp, > > void nfsd_filp_close(struct file *fp); > > +int nfsd_open_local_fh(struct net *net, > + struct auth_domain *dom, > + struct rpc_clnt *rpc_clnt, > + const struct cred *cred, > + const struct nfs_fh *nfs_fh, > + const fmode_t fmode, > + struct nfsd_file **pnf); > + > static inline int fh_want_write(struct svc_fh *fh) > { > int ret; > -- > 2.44.0 >
On Sat, 24 Aug 2024, Mike Snitzer wrote: > + > + /* Save client creds before calling nfsd_file_acquire_local which calls nfsd_setuser */ > + save_cred = get_current_cred(); I don't think this belongs here. I would rather than nfsd_file_acquire_local() saved and restored the cred so it could be called without concern for internal implementation details. > + > + /* 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; > + > + rpcauth_map_clnt_to_svc_cred_local(rpc_clnt, cred, &rq_cred); > + > + beres = nfsd_file_acquire_local(cl_nfssvc_net, &rq_cred, rpc_clnt->cl_vers, > + cl_nfssvc_dom, &fh, mayflags, pnf); > + if (beres) { > + status = nfs_stat_to_errno(be32_to_cpu(beres)); > + goto out_fh_put; > + } > +out_fh_put: > + fh_put(&fh); > + if (rq_cred.cr_group_info) > + put_group_info(rq_cred.cr_group_info); > + revert_creds(save_cred); > + nfsd_serv_put(nn); I think this is too early to be calling nfsd_serv_put(). I think it should be called when the IO completes - when nfs_to.nfsd_file_put() is called. nfs_to.nfsd_open_local_fh() and nfs_to.nfsd_file_get() should each get a ref to the server. nfsd_to.nfsd_file_put() should drop the ref. Note that nfs_do.nfsd_file_get() would not exactly be nfsd_file_get. So maybe a different name would suit. Thanks, NeilBrown
On Mon, Aug 26, 2024 at 10:53:25AM +1000, NeilBrown wrote: > On Sat, 24 Aug 2024, Mike Snitzer wrote: > > + > > + /* Save client creds before calling nfsd_file_acquire_local which calls nfsd_setuser */ > > + save_cred = get_current_cred(); > > I don't think this belongs here. I would rather than > nfsd_file_acquire_local() saved and restored the cred so it could be > called without concern for internal implementation details. OK, will fix. > > + > > + /* 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; > > + > > + rpcauth_map_clnt_to_svc_cred_local(rpc_clnt, cred, &rq_cred); > > + > > + beres = nfsd_file_acquire_local(cl_nfssvc_net, &rq_cred, rpc_clnt->cl_vers, > > + cl_nfssvc_dom, &fh, mayflags, pnf); > > + if (beres) { > > + status = nfs_stat_to_errno(be32_to_cpu(beres)); > > + goto out_fh_put; > > + } > > +out_fh_put: > > + fh_put(&fh); > > + if (rq_cred.cr_group_info) > > + put_group_info(rq_cred.cr_group_info); > > + revert_creds(save_cred); > > + nfsd_serv_put(nn); > > I think this is too early to be calling nfsd_serv_put(). > I think it should be called when the IO completes - when > nfs_to.nfsd_file_put() is called. > > nfs_to.nfsd_open_local_fh() and nfs_to.nfsd_file_get() should each get a ref to the > server. > nfsd_to.nfsd_file_put() should drop the ref. > > Note that nfs_do.nfsd_file_get() would not exactly be nfsd_file_get. So > maybe a different name would suit. Yes, you're right. I'll get it fixed. Thanks!
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..1fca57c79c60 100644 --- a/fs/nfsd/Kconfig +++ b/fs/nfsd/Kconfig @@ -90,6 +90,20 @@ 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 + 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 bypass using the NFS + protocol when issuing reads, writes and commits to the 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 2a79c45ca27a..d7c6122231f4 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..8e0cce835f81 --- /dev/null +++ b/fs/nfsd/localio.c @@ -0,0 +1,108 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * NFS server support for local clients to bypass network stack + * + * Copyright (C) 2014 Weston Andros Adamson <dros@primarydata.com> + * Copyright (C) 2019 Trond Myklebust <trond.myklebust@hammerspace.com> + * Copyright (C) 2024 Mike Snitzer <snitzer@hammerspace.com> + */ + +#include <linux/exportfs.h> +#include <linux/sunrpc/svcauth_gss.h> +#include <linux/sunrpc/clnt.h> +#include <linux/nfs.h> +#include <linux/nfs_common.h> +#include <linux/nfslocalio.h> +#include <linux/string.h> + +#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 @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 + * @pnf: returned nfsd_file pointer that maps to @nfs_fh + * + * 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, caller is responsible for calling nfsd_file_put. Also + * note that this is called from nfs.ko via find_symbol() to avoid an explicit + * dependency on knfsd. So, there is no forward declaration in a header file + * for it that is shared with the client. + */ +int 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, + struct nfsd_file **pnf) +{ + int mayflags = NFSD_MAY_LOCALIO; + int status = 0; + struct nfsd_net *nn; + const struct cred *save_cred; + struct svc_cred rq_cred; + struct svc_fh fh; + __be32 beres; + + if (nfs_fh->size > NFS4_FHSIZE) + return -EINVAL; + + /* Not running in nfsd context, must safely get reference on nfsd_serv */ + cl_nfssvc_net = maybe_get_net(cl_nfssvc_net); + if (!cl_nfssvc_net) + return -ENXIO; + nn = net_generic(cl_nfssvc_net, nfsd_net_id); + + /* The server may already be shutting down, disallow new localio */ + if (unlikely(!nfsd_serv_try_get(nn))) { + status = -ENXIO; + goto out_net; + } + + /* Save client creds before calling nfsd_file_acquire_local which calls nfsd_setuser */ + save_cred = get_current_cred(); + + /* 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; + + rpcauth_map_clnt_to_svc_cred_local(rpc_clnt, cred, &rq_cred); + + beres = nfsd_file_acquire_local(cl_nfssvc_net, &rq_cred, rpc_clnt->cl_vers, + cl_nfssvc_dom, &fh, mayflags, pnf); + if (beres) { + status = nfs_stat_to_errno(be32_to_cpu(beres)); + goto out_fh_put; + } +out_fh_put: + fh_put(&fh); + if (rq_cred.cr_group_info) + put_group_info(rq_cred.cr_group_info); + revert_creds(save_cred); + nfsd_serv_put(nn); +out_net: + put_net(cl_nfssvc_net); + return status; +} +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/netns.h b/fs/nfsd/netns.h index 238fc4e56e53..e2d953f21dde 100644 --- a/fs/nfsd/netns.h +++ b/fs/nfsd/netns.h @@ -13,6 +13,7 @@ #include <linux/filelock.h> #include <linux/nfs4.h> #include <linux/percpu_counter.h> +#include <linux/percpu-refcount.h> #include <linux/siphash.h> #include <linux/sunrpc/stats.h> @@ -139,7 +140,9 @@ struct nfsd_net { struct svc_info nfsd_info; #define nfsd_serv nfsd_info.serv - + struct percpu_ref nfsd_serv_ref; + struct completion nfsd_serv_confirm_done; + struct completion nfsd_serv_free_done; /* * clientid and stateid data for construction of net unique COPY @@ -221,6 +224,9 @@ struct nfsd_net { extern bool nfsd_support_version(int vers); extern unsigned int nfsd_net_id; +bool nfsd_serv_try_get(struct nfsd_net *nn); +void nfsd_serv_put(struct nfsd_net *nn); + void nfsd_copy_write_verifier(__be32 verf[2], struct nfsd_net *nn); void nfsd_reset_write_verifier(struct nfsd_net *nn); #endif /* __NFSD_NETNS_H__ */ diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c index b02eaaea7d62..c639fbe4d8c2 100644 --- a/fs/nfsd/nfssvc.c +++ b/fs/nfsd/nfssvc.c @@ -192,6 +192,30 @@ int nfsd_minorversion(struct nfsd_net *nn, u32 minorversion, enum vers_op change return 0; } +bool nfsd_serv_try_get(struct nfsd_net *nn) +{ + return percpu_ref_tryget_live(&nn->nfsd_serv_ref); +} + +void nfsd_serv_put(struct nfsd_net *nn) +{ + percpu_ref_put(&nn->nfsd_serv_ref); +} + +static void nfsd_serv_done(struct percpu_ref *ref) +{ + struct nfsd_net *nn = container_of(ref, struct nfsd_net, nfsd_serv_ref); + + complete(&nn->nfsd_serv_confirm_done); +} + +static void nfsd_serv_free(struct percpu_ref *ref) +{ + struct nfsd_net *nn = container_of(ref, struct nfsd_net, nfsd_serv_ref); + + complete(&nn->nfsd_serv_free_done); +} + /* * Maximum number of nfsd processes */ @@ -391,6 +415,7 @@ static void nfsd_shutdown_net(struct net *net) lockd_down(net); nn->lockd_up = false; } + percpu_ref_exit(&nn->nfsd_serv_ref); nn->nfsd_net_up = false; nfsd_shutdown_generic(); } @@ -470,6 +495,13 @@ void nfsd_destroy_serv(struct net *net) struct nfsd_net *nn = net_generic(net, nfsd_net_id); struct svc_serv *serv = nn->nfsd_serv; + lockdep_assert_held(&nfsd_mutex); + + percpu_ref_kill_and_confirm(&nn->nfsd_serv_ref, nfsd_serv_done); + wait_for_completion(&nn->nfsd_serv_confirm_done); + wait_for_completion(&nn->nfsd_serv_free_done); + /* percpu_ref_exit is called in nfsd_shutdown_net */ + spin_lock(&nfsd_notifier_lock); nn->nfsd_serv = NULL; spin_unlock(&nfsd_notifier_lock); @@ -594,6 +626,13 @@ int nfsd_create_serv(struct net *net) if (nn->nfsd_serv) return 0; + error = percpu_ref_init(&nn->nfsd_serv_ref, nfsd_serv_free, + 0, GFP_KERNEL); + if (error) + return error; + init_completion(&nn->nfsd_serv_free_done); + init_completion(&nn->nfsd_serv_confirm_done); + if (nfsd_max_blksize == 0) nfsd_max_blksize = nfsd_get_default_max_blksize(); nfsd_reset_versions(nn); diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h index 77bbd23aa150..9c0610fdd11c 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..ec8a8aae540b 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 +160,14 @@ __be32 nfsd_permission(struct svc_cred *cred, struct svc_export *exp, void nfsd_filp_close(struct file *fp); +int nfsd_open_local_fh(struct net *net, + struct auth_domain *dom, + struct rpc_clnt *rpc_clnt, + const struct cred *cred, + const struct nfs_fh *nfs_fh, + const fmode_t fmode, + struct nfsd_file **pnf); + static inline int fh_want_write(struct svc_fh *fh) { int ret;