[nfs-utils,v2,4/4] systemd: add a generator for the rpc_pipefs mountpoint

Commit Message

Scott Mayhew April 5, 2017, 9:12 p.m. UTC

The nfs.conf has config options for the rpc_pipefs mountpoint.
Currently, changing these from the default also requires manually
overriding the systemd unit files that are hard-coded to mount the
filesystem on /var/lib/nfs/rpc_pipefs.

This patch adds a generator that creates a mount unit file for the
rpc_pipefs when a non-default value is specified in /etc/nfs.conf, as
well as a target unit file to override the dependencies for the systemd
units using the rpc_pipefs.  The blkmapd, idmapd, and gssd service unit
files have been modified to define their dependencies on the rpc_pipefs
mountpoint indirectly via the rpc_pipefs target unit file.

This patch also removes the dependency on the rpc_pipefs from the
rpc-svcgssd.service unit file.  rpc.svcgssd uses the sunrpc cache
mechanism to exchange data with the kernel, not the rpc_pipefs.

Signed-off-by: Scott Mayhew <[e-mail]>
---
 .gitignore                     |   1 +
 systemd/Makefile.am            |   5 +-
 systemd/nfs-blkmap.service     |   4 +-
 systemd/nfs-idmapd.service     |   4 +-
 systemd/rpc-gssd.service.in    |   4 +-
 systemd/rpc-pipefs-generator.c | 216 +++++++++++++++++++++++++++++++++++++++++
 systemd/rpc-svcgssd.service    |   3 +-
 systemd/rpc_pipefs.target      |   3 +
 8 files changed, 231 insertions(+), 9 deletions(-)
 create mode 100644 systemd/rpc-pipefs-generator.c
 create mode 100644 systemd/rpc_pipefs.target

Comments

NeilBrown April 6, 2017, 5:34 a.m. UTC | #1

On Wed, Apr 05 2017, Scott Mayhew wrote:

> The nfs.conf has config options for the rpc_pipefs mountpoint.
> Currently, changing these from the default also requires manually
> overriding the systemd unit files that are hard-coded to mount the
> filesystem on /var/lib/nfs/rpc_pipefs.
>
> This patch adds a generator that creates a mount unit file for the
> rpc_pipefs when a non-default value is specified in /etc/nfs.conf, as
> well as a target unit file to override the dependencies for the systemd
> units using the rpc_pipefs.  The blkmapd, idmapd, and gssd service unit
> files have been modified to define their dependencies on the rpc_pipefs
> mountpoint indirectly via the rpc_pipefs target unit file.
>
> This patch also removes the dependency on the rpc_pipefs from the
> rpc-svcgssd.service unit file.  rpc.svcgssd uses the sunrpc cache
> mechanism to exchange data with the kernel, not the rpc_pipefs.
>
> Signed-off-by: Scott Mayhew <[e-mail]>

I was reading through this, which I really thought would be a good patch
that I would give an Ack to, and looking at some of the detail involved,
I started to wonder if we were really doing the right thing here.
You go to some trouble to make the name of the .mount unit file match
the name of the location of the mountpoint.  Is that really necessary?

Unit files created by systemd-fstab-generator do follow that pattern,
but they don't have to.

Maybe we should just:

1/ rename var-lib-nfs-rpc_pipefs.mount to rpc_pipefs.mount,
   and modify the dependencies accordingly.

2/ write a generator which (if necessary) creates a drop-in for
   rpc_pipefs.mount which simply overrides "Where".

 i.e /run/systemd/generator/rpc_pipefs.mount.d/pipefs.conf
 would contain

    [Mount]
    Where=/foo/bar

I'm sorry to discard your good work, but I now think that a lot of it is
unnecessary.  Sorry for not seeing that earlier.

Thanks,
NeilBrown


> ---
>  .gitignore                     |   1 +
>  systemd/Makefile.am            |   5 +-
>  systemd/nfs-blkmap.service     |   4 +-
>  systemd/nfs-idmapd.service     |   4 +-
>  systemd/rpc-gssd.service.in    |   4 +-
>  systemd/rpc-pipefs-generator.c | 216 +++++++++++++++++++++++++++++++++++++++++
>  systemd/rpc-svcgssd.service    |   3 +-
>  systemd/rpc_pipefs.target      |   3 +
>  8 files changed, 231 insertions(+), 9 deletions(-)
>  create mode 100644 systemd/rpc-pipefs-generator.c
>  create mode 100644 systemd/rpc_pipefs.target
>
> diff --git a/.gitignore b/.gitignore
> index 126d12c..941aca0 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -70,6 +70,7 @@ tests/nsm_client/nlm_sm_inter_svc.c
>  tests/nsm_client/nlm_sm_inter_xdr.c
>  utils/nfsidmap/nfsidmap
>  systemd/nfs-server-generator
> +systemd/rpc-pipefs-generator
>  systemd/nfs-config.service
>  systemd/rpc-gssd.service
>  # cscope database files
> diff --git a/systemd/Makefile.am b/systemd/Makefile.am
> index 0d15b9f..4becb77 100644
> --- a/systemd/Makefile.am
> +++ b/systemd/Makefile.am
> @@ -4,6 +4,7 @@ MAINTAINERCLEANFILES = Makefile.in
>  
>  unit_files =  \
>      nfs-client.target \
> +    rpc_pipefs.target \
>      \
>      nfs-mountd.service \
>      nfs-server.service \
> @@ -42,12 +43,14 @@ EXTRA_DIST = $(unit_files) $(man5_MANS) $(man7_MANS)
>  unit_dir = /usr/lib/systemd/system
>  generator_dir = /usr/lib/systemd/system-generators
>  
> -EXTRA_PROGRAMS	= nfs-server-generator
> +EXTRA_PROGRAMS	= nfs-server-generator rpc-pipefs-generator
>  genexecdir = $(generator_dir)
>  nfs_server_generator_LDADD = ../support/export/libexport.a \
>  			     ../support/nfs/libnfs.a \
>  			     ../support/misc/libmisc.a
>  
> +rpc_pipefs_generator_LDADD = ../support/nfs/libnfs.a
> +
>  if INSTALL_SYSTEMD
>  genexec_PROGRAMS = nfs-server-generator
>  install-data-hook: $(unit_files)
> diff --git a/systemd/nfs-blkmap.service b/systemd/nfs-blkmap.service
> index ddc324e..2bbcee6 100644
> --- a/systemd/nfs-blkmap.service
> +++ b/systemd/nfs-blkmap.service
> @@ -2,8 +2,8 @@
>  Description=pNFS block layout mapping daemon
>  DefaultDependencies=no
>  Conflicts=umount.target
> -After=var-lib-nfs-rpc_pipefs.mount
> -Requires=var-lib-nfs-rpc_pipefs.mount
> +After=rpc_pipefs.target
> +Requires=rpc_pipefs.target
>  
>  PartOf=nfs-utils.service
>  
> diff --git a/systemd/nfs-idmapd.service b/systemd/nfs-idmapd.service
> index acca86b..f38fe52 100644
> --- a/systemd/nfs-idmapd.service
> +++ b/systemd/nfs-idmapd.service
> @@ -1,8 +1,8 @@
>  [Unit]
>  Description=NFSv4 ID-name mapping service
>  DefaultDependencies=no
> -Requires=var-lib-nfs-rpc_pipefs.mount
> -After=var-lib-nfs-rpc_pipefs.mount local-fs.target
> +Requires=rpc_pipefs.target
> +After=rpc_pipefs.target local-fs.target
>  
>  BindsTo=nfs-server.service
>  
> diff --git a/systemd/rpc-gssd.service.in b/systemd/rpc-gssd.service.in
> index b353027..6807db3 100644
> --- a/systemd/rpc-gssd.service.in
> +++ b/systemd/rpc-gssd.service.in
> @@ -2,8 +2,8 @@
>  Description=RPC security service for NFS client and server
>  DefaultDependencies=no
>  Conflicts=umount.target
> -Requires=var-lib-nfs-rpc_pipefs.mount
> -After=var-lib-nfs-rpc_pipefs.mount
> +Requires=rpc_pipefs.target
> +After=rpc_pipefs.target
>  
>  ConditionPathExists=@_sysconfdir@/krb5.keytab
>  
> diff --git a/systemd/rpc-pipefs-generator.c b/systemd/rpc-pipefs-generator.c
> new file mode 100644
> index 0000000..b0a6c19
> --- /dev/null
> +++ b/systemd/rpc-pipefs-generator.c
> @@ -0,0 +1,216 @@
> +/*
> + * rpc-pipefs-generator:
> + *   systemd generator to create ordering dependencies between
> + *   nfs services and the rpc_pipefs mountpoint
> + */
> +
> +#ifdef HAVE_CONFIG_H
> +#include <config.h>
> +#endif
> +
> +#include <sys/stat.h>
> +#include <sys/types.h>
> +#include <unistd.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <ctype.h>
> +#include <stdio.h>
> +#include <mntent.h>
> +
> +#include "nfslib.h"
> +#include "conffile.h"
> +
> +#define RPC_PIPEFS_DEFAULT "/var/lib/nfs/rpc_pipefs"
> +char *conf_path = NFS_CONFFILE;
> +
> +int systemd_len(char *path)
> +{
> +	char *p;
> +	int len = 0;
> +
> +	p = path;
> +	while (*p == '/')
> +		p++;
> +
> +	if (!*p)
> +		/* "/" becomes "-", otherwise leading "/" is ignored */
> +		return 1;
> +
> +	while (*p) {
> +		unsigned char c = *p++;
> +
> +		if (c == '/') {
> +			/* multiple non-trailing slashes become '-' */
> +			while (*p == '/')
> +				p++;
> +			if (*p)
> +				len++;
> +		} else if (isalnum(c) || c == ':' || c == '.' || c == '_')
> +			len++;
> +		else {
> +			len += 4;
> +		}
> +	}
> +
> +	return len;
> +}
> +
> +char *systemd_escape(char *path)
> +{
> +	char *result = NULL;
> +	char *p;
> +	int len;
> +
> +	len = systemd_len(path);
> +	if (!len)
> +		goto out;
> +
> +	result = malloc(len + strlen(".mount") + 1);
> +	if (!result)
> +		goto out;
> +
> +	p = result;
> +	while (*path == '/')
> +		path++;
> +	if (!*path) {
> +		/* "/" becomes "-", otherwise leading "/" is ignored */
> +		*p++ = '-';
> +		goto out_append;
> +	}
> +	while (*path) {
> +		unsigned char c = *path++;
> +
> +		if (c == '/') {
> +			/* multiple non-trailing slashes become '-' */
> +			while (*path == '/')
> +				path++;
> +			if (*path)
> +				*p++ = '-';
> +		} else if (isalnum(c) || c == ':' || c == '.' || c == '_')
> +			*p++ = c;
> +		else {
> +			*p++ = '\\';
> +			*p++ = 'x';
> +			*p++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
> +			*p++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
> +		}
> +	}
> +
> +out_append:
> +	sprintf(p, ".mount");
> +out:
> +	return result;
> +}
> +
> +static int generate_mount_unit(const char *pipefs_path, const char *pipefs_unit,
> +			       const char *dirname)
> +{
> +	char	*path;
> +	FILE	*f;
> +
> +	path = malloc(strlen(dirname) + 1 + strlen(pipefs_unit));
> +	if (!path)
> +		return 1;
> +	sprintf(path, "%s/%s", dirname, pipefs_unit);
> +	f = fopen(path, "w");
> +	if (!f)
> +		return 1;
> +
> +	fprintf(f, "# Automatically generated by rpc-pipefs-generator\n\n[Unit]\n");
> +	fprintf(f, "Description=RPC Pipe File System\n");
> +	fprintf(f, "DefaultDependencies=no\n");
> +	fprintf(f, "After=systemd-tmpfiles-setup.service\n");
> +	fprintf(f, "Conflicts=umount.target\n");
> +	fprintf(f, "\n[Mount]\n");
> +	fprintf(f, "What=sunrpc\n");
> +	fprintf(f, "Where=%s\n", pipefs_path);
> +	fprintf(f, "Type=rpc_pipefs\n");
> +
> +	fclose(f);
> +	return 0;
> +}
> +
> +static
> +int generate_target(char *pipefs_path, const char *dirname)
> +{
> +	char	*path;
> +	char	filebase[] = "/rpc_pipefs.target";
> +	char	*pipefs_unit;
> +	FILE	*f;
> +	int 	ret = 0;
> +
> +	pipefs_unit = systemd_escape(pipefs_path);
> +	if (!pipefs_unit)
> +		return 1;
> +
> +	ret = generate_mount_unit(pipefs_path, pipefs_unit, dirname);
> +	if (ret)
> +		return ret;
> +
> +	path = malloc(strlen(dirname) + 1 + sizeof(filebase));
> +	if (!path)
> +		return 2;
> +	sprintf(path, "%s", dirname);
> +	mkdir(path, 0755);
> +	strcat(path, filebase);
> +	f = fopen(path, "w");
> +	if (!f)
> +		return 1;
> +
> +	fprintf(f, "# Automatically generated by rpc-pipefs-generator\n\n[Unit]\n");
> +	fprintf(f, "Requires=%s\n", pipefs_unit);
> +	fprintf(f, "After=%s\n", pipefs_unit);
> +	fclose(f);
> +
> +	return 0;
> +}
> +
> +static int is_non_pipefs_mountpoint(char *path)
> +{
> +	FILE		*mtab;
> +	struct mntent	*mnt;
> +
> +	mtab = setmntent("/etc/mtab", "r");
> +	if (!mtab)
> +		return 0;
> +
> +	while ((mnt = getmntent(mtab)) != NULL) {
> +		if (strlen(mnt->mnt_dir) != strlen(path))
> +			continue;
> +		if (strncmp(mnt->mnt_dir, path, strlen(mnt->mnt_dir)))
> +			continue;
> +		if (strncmp(mnt->mnt_type, "rpc_pipefs", strlen(mnt->mnt_type)))
> +			break;
> +	}
> +	fclose(mtab);
> +	return mnt != NULL;
> +}
> +
> +int main(int argc, char *argv[])
> +{
> +	int 	ret;
> +	char	*s;
> +
> +	/* Avoid using any external services */
> +	xlog_syslog(0);
> +
> +	if (argc != 4 || argv[1][0] != '/') {
> +		fprintf(stderr, "rpc-pipefs-generator: create systemd dependencies for nfs services\n");
> +		fprintf(stderr, "Usage: normal-dir early-dir late-dir\n");
> +		exit(1);
> +	}
> +
> +	conf_init();
> +	s = conf_get_str("global", "pipefs-directory");
> +	if (!s)
> +		exit(0);
> +	if (strlen(s) == strlen(RPC_PIPEFS_DEFAULT) &&
> +			strcmp(s, RPC_PIPEFS_DEFAULT) == 0)
> +		exit(0);
> +
> +	if (is_non_pipefs_mountpoint(s))
> +		exit(1);
> +
> +	ret = generate_target(s, argv[1]);
> +	exit(ret);
> +}
> diff --git a/systemd/rpc-svcgssd.service b/systemd/rpc-svcgssd.service
> index 7187e3c..cb2bcd4 100644
> --- a/systemd/rpc-svcgssd.service
> +++ b/systemd/rpc-svcgssd.service
> @@ -1,8 +1,7 @@
>  [Unit]
>  Description=RPC security service for NFS server
>  DefaultDependencies=no
> -Requires=var-lib-nfs-rpc_pipefs.mount
> -After=var-lib-nfs-rpc_pipefs.mount local-fs.target
> +After=local-fs.target
>  PartOf=nfs-server.service
>  PartOf=nfs-utils.service
>  
> diff --git a/systemd/rpc_pipefs.target b/systemd/rpc_pipefs.target
> new file mode 100644
> index 0000000..01d4d27
> --- /dev/null
> +++ b/systemd/rpc_pipefs.target
> @@ -0,0 +1,3 @@
> +[Unit]
> +Requires=var-lib-nfs-rpc_pipefs.mount
> +After=var-lib-nfs-rpc_pipefs.mount
> -- 
> 2.9.3
>
> --
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Scott Mayhew April 6, 2017, 12:06 p.m. UTC | #2

On Thu, 06 Apr 2017, NeilBrown wrote:

> On Wed, Apr 05 2017, Scott Mayhew wrote:
> 
> > The nfs.conf has config options for the rpc_pipefs mountpoint.
> > Currently, changing these from the default also requires manually
> > overriding the systemd unit files that are hard-coded to mount the
> > filesystem on /var/lib/nfs/rpc_pipefs.
> >
> > This patch adds a generator that creates a mount unit file for the
> > rpc_pipefs when a non-default value is specified in /etc/nfs.conf, as
> > well as a target unit file to override the dependencies for the systemd
> > units using the rpc_pipefs.  The blkmapd, idmapd, and gssd service unit
> > files have been modified to define their dependencies on the rpc_pipefs
> > mountpoint indirectly via the rpc_pipefs target unit file.
> >
> > This patch also removes the dependency on the rpc_pipefs from the
> > rpc-svcgssd.service unit file.  rpc.svcgssd uses the sunrpc cache
> > mechanism to exchange data with the kernel, not the rpc_pipefs.
> >
> > Signed-off-by: Scott Mayhew <[e-mail]>
> 
> I was reading through this, which I really thought would be a good patch
> that I would give an Ack to, and looking at some of the detail involved,
> I started to wonder if we were really doing the right thing here.
> You go to some trouble to make the name of the .mount unit file match
> the name of the location of the mountpoint.  Is that really necessary?
> 
> Unit files created by systemd-fstab-generator do follow that pattern,
> but they don't have to.

I didn't know that.
> 
> Maybe we should just:
> 
> 1/ rename var-lib-nfs-rpc_pipefs.mount to rpc_pipefs.mount,
>    and modify the dependencies accordingly.
> 
> 2/ write a generator which (if necessary) creates a drop-in for
>    rpc_pipefs.mount which simply overrides "Where".
> 
>  i.e /run/systemd/generator/rpc_pipefs.mount.d/pipefs.conf
>  would contain
> 
>     [Mount]
>     Where=/foo/bar

Sounds good to me, I'll take a look.

-Scott
> 
> I'm sorry to discard your good work, but I now think that a lot of it is
> unnecessary.  Sorry for not seeing that earlier.
> 
> Thanks,
> NeilBrown
> 
> 
> > ---
> >  .gitignore                     |   1 +
> >  systemd/Makefile.am            |   5 +-
> >  systemd/nfs-blkmap.service     |   4 +-
> >  systemd/nfs-idmapd.service     |   4 +-
> >  systemd/rpc-gssd.service.in    |   4 +-
> >  systemd/rpc-pipefs-generator.c | 216 +++++++++++++++++++++++++++++++++++++++++
> >  systemd/rpc-svcgssd.service    |   3 +-
> >  systemd/rpc_pipefs.target      |   3 +
> >  8 files changed, 231 insertions(+), 9 deletions(-)
> >  create mode 100644 systemd/rpc-pipefs-generator.c
> >  create mode 100644 systemd/rpc_pipefs.target
> >
> > diff --git a/.gitignore b/.gitignore
> > index 126d12c..941aca0 100644
> > --- a/.gitignore
> > +++ b/.gitignore
> > @@ -70,6 +70,7 @@ tests/nsm_client/nlm_sm_inter_svc.c
> >  tests/nsm_client/nlm_sm_inter_xdr.c
> >  utils/nfsidmap/nfsidmap
> >  systemd/nfs-server-generator
> > +systemd/rpc-pipefs-generator
> >  systemd/nfs-config.service
> >  systemd/rpc-gssd.service
> >  # cscope database files
> > diff --git a/systemd/Makefile.am b/systemd/Makefile.am
> > index 0d15b9f..4becb77 100644
> > --- a/systemd/Makefile.am
> > +++ b/systemd/Makefile.am
> > @@ -4,6 +4,7 @@ MAINTAINERCLEANFILES = Makefile.in
> >  
> >  unit_files =  \
> >      nfs-client.target \
> > +    rpc_pipefs.target \
> >      \
> >      nfs-mountd.service \
> >      nfs-server.service \
> > @@ -42,12 +43,14 @@ EXTRA_DIST = $(unit_files) $(man5_MANS) $(man7_MANS)
> >  unit_dir = /usr/lib/systemd/system
> >  generator_dir = /usr/lib/systemd/system-generators
> >  
> > -EXTRA_PROGRAMS	= nfs-server-generator
> > +EXTRA_PROGRAMS	= nfs-server-generator rpc-pipefs-generator
> >  genexecdir = $(generator_dir)
> >  nfs_server_generator_LDADD = ../support/export/libexport.a \
> >  			     ../support/nfs/libnfs.a \
> >  			     ../support/misc/libmisc.a
> >  
> > +rpc_pipefs_generator_LDADD = ../support/nfs/libnfs.a
> > +
> >  if INSTALL_SYSTEMD
> >  genexec_PROGRAMS = nfs-server-generator
> >  install-data-hook: $(unit_files)
> > diff --git a/systemd/nfs-blkmap.service b/systemd/nfs-blkmap.service
> > index ddc324e..2bbcee6 100644
> > --- a/systemd/nfs-blkmap.service
> > +++ b/systemd/nfs-blkmap.service
> > @@ -2,8 +2,8 @@
> >  Description=pNFS block layout mapping daemon
> >  DefaultDependencies=no
> >  Conflicts=umount.target
> > -After=var-lib-nfs-rpc_pipefs.mount
> > -Requires=var-lib-nfs-rpc_pipefs.mount
> > +After=rpc_pipefs.target
> > +Requires=rpc_pipefs.target
> >  
> >  PartOf=nfs-utils.service
> >  
> > diff --git a/systemd/nfs-idmapd.service b/systemd/nfs-idmapd.service
> > index acca86b..f38fe52 100644
> > --- a/systemd/nfs-idmapd.service
> > +++ b/systemd/nfs-idmapd.service
> > @@ -1,8 +1,8 @@
> >  [Unit]
> >  Description=NFSv4 ID-name mapping service
> >  DefaultDependencies=no
> > -Requires=var-lib-nfs-rpc_pipefs.mount
> > -After=var-lib-nfs-rpc_pipefs.mount local-fs.target
> > +Requires=rpc_pipefs.target
> > +After=rpc_pipefs.target local-fs.target
> >  
> >  BindsTo=nfs-server.service
> >  
> > diff --git a/systemd/rpc-gssd.service.in b/systemd/rpc-gssd.service.in
> > index b353027..6807db3 100644
> > --- a/systemd/rpc-gssd.service.in
> > +++ b/systemd/rpc-gssd.service.in
> > @@ -2,8 +2,8 @@
> >  Description=RPC security service for NFS client and server
> >  DefaultDependencies=no
> >  Conflicts=umount.target
> > -Requires=var-lib-nfs-rpc_pipefs.mount
> > -After=var-lib-nfs-rpc_pipefs.mount
> > +Requires=rpc_pipefs.target
> > +After=rpc_pipefs.target
> >  
> >  ConditionPathExists=@_sysconfdir@/krb5.keytab
> >  
> > diff --git a/systemd/rpc-pipefs-generator.c b/systemd/rpc-pipefs-generator.c
> > new file mode 100644
> > index 0000000..b0a6c19
> > --- /dev/null
> > +++ b/systemd/rpc-pipefs-generator.c
> > @@ -0,0 +1,216 @@
> > +/*
> > + * rpc-pipefs-generator:
> > + *   systemd generator to create ordering dependencies between
> > + *   nfs services and the rpc_pipefs mountpoint
> > + */
> > +
> > +#ifdef HAVE_CONFIG_H
> > +#include <config.h>
> > +#endif
> > +
> > +#include <sys/stat.h>
> > +#include <sys/types.h>
> > +#include <unistd.h>
> > +#include <stdlib.h>
> > +#include <string.h>
> > +#include <ctype.h>
> > +#include <stdio.h>
> > +#include <mntent.h>
> > +
> > +#include "nfslib.h"
> > +#include "conffile.h"
> > +
> > +#define RPC_PIPEFS_DEFAULT "/var/lib/nfs/rpc_pipefs"
> > +char *conf_path = NFS_CONFFILE;
> > +
> > +int systemd_len(char *path)
> > +{
> > +	char *p;
> > +	int len = 0;
> > +
> > +	p = path;
> > +	while (*p == '/')
> > +		p++;
> > +
> > +	if (!*p)
> > +		/* "/" becomes "-", otherwise leading "/" is ignored */
> > +		return 1;
> > +
> > +	while (*p) {
> > +		unsigned char c = *p++;
> > +
> > +		if (c == '/') {
> > +			/* multiple non-trailing slashes become '-' */
> > +			while (*p == '/')
> > +				p++;
> > +			if (*p)
> > +				len++;
> > +		} else if (isalnum(c) || c == ':' || c == '.' || c == '_')
> > +			len++;
> > +		else {
> > +			len += 4;
> > +		}
> > +	}
> > +
> > +	return len;
> > +}
> > +
> > +char *systemd_escape(char *path)
> > +{
> > +	char *result = NULL;
> > +	char *p;
> > +	int len;
> > +
> > +	len = systemd_len(path);
> > +	if (!len)
> > +		goto out;
> > +
> > +	result = malloc(len + strlen(".mount") + 1);
> > +	if (!result)
> > +		goto out;
> > +
> > +	p = result;
> > +	while (*path == '/')
> > +		path++;
> > +	if (!*path) {
> > +		/* "/" becomes "-", otherwise leading "/" is ignored */
> > +		*p++ = '-';
> > +		goto out_append;
> > +	}
> > +	while (*path) {
> > +		unsigned char c = *path++;
> > +
> > +		if (c == '/') {
> > +			/* multiple non-trailing slashes become '-' */
> > +			while (*path == '/')
> > +				path++;
> > +			if (*path)
> > +				*p++ = '-';
> > +		} else if (isalnum(c) || c == ':' || c == '.' || c == '_')
> > +			*p++ = c;
> > +		else {
> > +			*p++ = '\\';
> > +			*p++ = 'x';
> > +			*p++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
> > +			*p++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
> > +		}
> > +	}
> > +
> > +out_append:
> > +	sprintf(p, ".mount");
> > +out:
> > +	return result;
> > +}
> > +
> > +static int generate_mount_unit(const char *pipefs_path, const char *pipefs_unit,
> > +			       const char *dirname)
> > +{
> > +	char	*path;
> > +	FILE	*f;
> > +
> > +	path = malloc(strlen(dirname) + 1 + strlen(pipefs_unit));
> > +	if (!path)
> > +		return 1;
> > +	sprintf(path, "%s/%s", dirname, pipefs_unit);
> > +	f = fopen(path, "w");
> > +	if (!f)
> > +		return 1;
> > +
> > +	fprintf(f, "# Automatically generated by rpc-pipefs-generator\n\n[Unit]\n");
> > +	fprintf(f, "Description=RPC Pipe File System\n");
> > +	fprintf(f, "DefaultDependencies=no\n");
> > +	fprintf(f, "After=systemd-tmpfiles-setup.service\n");
> > +	fprintf(f, "Conflicts=umount.target\n");
> > +	fprintf(f, "\n[Mount]\n");
> > +	fprintf(f, "What=sunrpc\n");
> > +	fprintf(f, "Where=%s\n", pipefs_path);
> > +	fprintf(f, "Type=rpc_pipefs\n");
> > +
> > +	fclose(f);
> > +	return 0;
> > +}
> > +
> > +static
> > +int generate_target(char *pipefs_path, const char *dirname)
> > +{
> > +	char	*path;
> > +	char	filebase[] = "/rpc_pipefs.target";
> > +	char	*pipefs_unit;
> > +	FILE	*f;
> > +	int 	ret = 0;
> > +
> > +	pipefs_unit = systemd_escape(pipefs_path);
> > +	if (!pipefs_unit)
> > +		return 1;
> > +
> > +	ret = generate_mount_unit(pipefs_path, pipefs_unit, dirname);
> > +	if (ret)
> > +		return ret;
> > +
> > +	path = malloc(strlen(dirname) + 1 + sizeof(filebase));
> > +	if (!path)
> > +		return 2;
> > +	sprintf(path, "%s", dirname);
> > +	mkdir(path, 0755);
> > +	strcat(path, filebase);
> > +	f = fopen(path, "w");
> > +	if (!f)
> > +		return 1;
> > +
> > +	fprintf(f, "# Automatically generated by rpc-pipefs-generator\n\n[Unit]\n");
> > +	fprintf(f, "Requires=%s\n", pipefs_unit);
> > +	fprintf(f, "After=%s\n", pipefs_unit);
> > +	fclose(f);
> > +
> > +	return 0;
> > +}
> > +
> > +static int is_non_pipefs_mountpoint(char *path)
> > +{
> > +	FILE		*mtab;
> > +	struct mntent	*mnt;
> > +
> > +	mtab = setmntent("/etc/mtab", "r");
> > +	if (!mtab)
> > +		return 0;
> > +
> > +	while ((mnt = getmntent(mtab)) != NULL) {
> > +		if (strlen(mnt->mnt_dir) != strlen(path))
> > +			continue;
> > +		if (strncmp(mnt->mnt_dir, path, strlen(mnt->mnt_dir)))
> > +			continue;
> > +		if (strncmp(mnt->mnt_type, "rpc_pipefs", strlen(mnt->mnt_type)))
> > +			break;
> > +	}
> > +	fclose(mtab);
> > +	return mnt != NULL;
> > +}
> > +
> > +int main(int argc, char *argv[])
> > +{
> > +	int 	ret;
> > +	char	*s;
> > +
> > +	/* Avoid using any external services */
> > +	xlog_syslog(0);
> > +
> > +	if (argc != 4 || argv[1][0] != '/') {
> > +		fprintf(stderr, "rpc-pipefs-generator: create systemd dependencies for nfs services\n");
> > +		fprintf(stderr, "Usage: normal-dir early-dir late-dir\n");
> > +		exit(1);
> > +	}
> > +
> > +	conf_init();
> > +	s = conf_get_str("global", "pipefs-directory");
> > +	if (!s)
> > +		exit(0);
> > +	if (strlen(s) == strlen(RPC_PIPEFS_DEFAULT) &&
> > +			strcmp(s, RPC_PIPEFS_DEFAULT) == 0)
> > +		exit(0);
> > +
> > +	if (is_non_pipefs_mountpoint(s))
> > +		exit(1);
> > +
> > +	ret = generate_target(s, argv[1]);
> > +	exit(ret);
> > +}
> > diff --git a/systemd/rpc-svcgssd.service b/systemd/rpc-svcgssd.service
> > index 7187e3c..cb2bcd4 100644
> > --- a/systemd/rpc-svcgssd.service
> > +++ b/systemd/rpc-svcgssd.service
> > @@ -1,8 +1,7 @@
> >  [Unit]
> >  Description=RPC security service for NFS server
> >  DefaultDependencies=no
> > -Requires=var-lib-nfs-rpc_pipefs.mount
> > -After=var-lib-nfs-rpc_pipefs.mount local-fs.target
> > +After=local-fs.target
> >  PartOf=nfs-server.service
> >  PartOf=nfs-utils.service
> >  
> > diff --git a/systemd/rpc_pipefs.target b/systemd/rpc_pipefs.target
> > new file mode 100644
> > index 0000000..01d4d27
> > --- /dev/null
> > +++ b/systemd/rpc_pipefs.target
> > @@ -0,0 +1,3 @@
> > +[Unit]
> > +Requires=var-lib-nfs-rpc_pipefs.mount
> > +After=var-lib-nfs-rpc_pipefs.mount
> > -- 
> > 2.9.3
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> > the body of a message to [e-mail]
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html


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Scott Mayhew April 6, 2017, 12:29 p.m. UTC | #3

On Thu, 06 Apr 2017, NeilBrown wrote:

> On Wed, Apr 05 2017, Scott Mayhew wrote:
> 
> > The nfs.conf has config options for the rpc_pipefs mountpoint.
> > Currently, changing these from the default also requires manually
> > overriding the systemd unit files that are hard-coded to mount the
> > filesystem on /var/lib/nfs/rpc_pipefs.
> >
> > This patch adds a generator that creates a mount unit file for the
> > rpc_pipefs when a non-default value is specified in /etc/nfs.conf, as
> > well as a target unit file to override the dependencies for the systemd
> > units using the rpc_pipefs.  The blkmapd, idmapd, and gssd service unit
> > files have been modified to define their dependencies on the rpc_pipefs
> > mountpoint indirectly via the rpc_pipefs target unit file.
> >
> > This patch also removes the dependency on the rpc_pipefs from the
> > rpc-svcgssd.service unit file.  rpc.svcgssd uses the sunrpc cache
> > mechanism to exchange data with the kernel, not the rpc_pipefs.
> >
> > Signed-off-by: Scott Mayhew <[e-mail]>
> 
> I was reading through this, which I really thought would be a good patch
> that I would give an Ack to, and looking at some of the detail involved,
> I started to wonder if we were really doing the right thing here.
> You go to some trouble to make the name of the .mount unit file match
> the name of the location of the mountpoint.  Is that really necessary?
> 
> Unit files created by systemd-fstab-generator do follow that pattern,
> but they don't have to.

> 
> Maybe we should just:
> 
> 1/ rename var-lib-nfs-rpc_pipefs.mount to rpc_pipefs.mount,
>    and modify the dependencies accordingly.
> 
The mount doesn't work when I change the name.

[root@fedora25 ~]# systemctl status rpc_pipefs.mount
● rpc_pipefs.mount - RPC Pipe File System
   Loaded: error (Reason: Invalid argument)
   Active: inactive (dead)
    Where: /var/lib/nfs/rpc_pipefs
     What: sunrpc

Apr 06 08:17:59 localhost.localdomain systemd[1]: rpc_pipefs.mount: Where= setting doesn't match unit name. Refusing.


Looking back at systemd.mount(5), it looks like they do have to follow
that pattern:

       Mount units must be named after the mount point directories they control.
       Example: the mount point /home/lennart must be configured in a unit file
       home-lennart.mount. For details about the escaping logic used to convert a
       file system path to a unit name, see systemd.unit(5). Note that mount units
       cannot be templated, nor is possible to add multiple names to a mount unit
       by creating additional symlinks to it.


-Scott

> 2/ write a generator which (if necessary) creates a drop-in for
>    rpc_pipefs.mount which simply overrides "Where".
> 
>  i.e /run/systemd/generator/rpc_pipefs.mount.d/pipefs.conf
>  would contain
> 
>     [Mount]
>     Where=/foo/bar

> 
> I'm sorry to discard your good work, but I now think that a lot of it is
> unnecessary.  Sorry for not seeing that earlier.
> 
> Thanks,
> NeilBrown
> 
> 
> > ---
> >  .gitignore                     |   1 +
> >  systemd/Makefile.am            |   5 +-
> >  systemd/nfs-blkmap.service     |   4 +-
> >  systemd/nfs-idmapd.service     |   4 +-
> >  systemd/rpc-gssd.service.in    |   4 +-
> >  systemd/rpc-pipefs-generator.c | 216 +++++++++++++++++++++++++++++++++++++++++
> >  systemd/rpc-svcgssd.service    |   3 +-
> >  systemd/rpc_pipefs.target      |   3 +
> >  8 files changed, 231 insertions(+), 9 deletions(-)
> >  create mode 100644 systemd/rpc-pipefs-generator.c
> >  create mode 100644 systemd/rpc_pipefs.target
> >
> > diff --git a/.gitignore b/.gitignore
> > index 126d12c..941aca0 100644
> > --- a/.gitignore
> > +++ b/.gitignore
> > @@ -70,6 +70,7 @@ tests/nsm_client/nlm_sm_inter_svc.c
> >  tests/nsm_client/nlm_sm_inter_xdr.c
> >  utils/nfsidmap/nfsidmap
> >  systemd/nfs-server-generator
> > +systemd/rpc-pipefs-generator
> >  systemd/nfs-config.service
> >  systemd/rpc-gssd.service
> >  # cscope database files
> > diff --git a/systemd/Makefile.am b/systemd/Makefile.am
> > index 0d15b9f..4becb77 100644
> > --- a/systemd/Makefile.am
> > +++ b/systemd/Makefile.am
> > @@ -4,6 +4,7 @@ MAINTAINERCLEANFILES = Makefile.in
> >  
> >  unit_files =  \
> >      nfs-client.target \
> > +    rpc_pipefs.target \
> >      \
> >      nfs-mountd.service \
> >      nfs-server.service \
> > @@ -42,12 +43,14 @@ EXTRA_DIST = $(unit_files) $(man5_MANS) $(man7_MANS)
> >  unit_dir = /usr/lib/systemd/system
> >  generator_dir = /usr/lib/systemd/system-generators
> >  
> > -EXTRA_PROGRAMS	= nfs-server-generator
> > +EXTRA_PROGRAMS	= nfs-server-generator rpc-pipefs-generator
> >  genexecdir = $(generator_dir)
> >  nfs_server_generator_LDADD = ../support/export/libexport.a \
> >  			     ../support/nfs/libnfs.a \
> >  			     ../support/misc/libmisc.a
> >  
> > +rpc_pipefs_generator_LDADD = ../support/nfs/libnfs.a
> > +
> >  if INSTALL_SYSTEMD
> >  genexec_PROGRAMS = nfs-server-generator
> >  install-data-hook: $(unit_files)
> > diff --git a/systemd/nfs-blkmap.service b/systemd/nfs-blkmap.service
> > index ddc324e..2bbcee6 100644
> > --- a/systemd/nfs-blkmap.service
> > +++ b/systemd/nfs-blkmap.service
> > @@ -2,8 +2,8 @@
> >  Description=pNFS block layout mapping daemon
> >  DefaultDependencies=no
> >  Conflicts=umount.target
> > -After=var-lib-nfs-rpc_pipefs.mount
> > -Requires=var-lib-nfs-rpc_pipefs.mount
> > +After=rpc_pipefs.target
> > +Requires=rpc_pipefs.target
> >  
> >  PartOf=nfs-utils.service
> >  
> > diff --git a/systemd/nfs-idmapd.service b/systemd/nfs-idmapd.service
> > index acca86b..f38fe52 100644
> > --- a/systemd/nfs-idmapd.service
> > +++ b/systemd/nfs-idmapd.service
> > @@ -1,8 +1,8 @@
> >  [Unit]
> >  Description=NFSv4 ID-name mapping service
> >  DefaultDependencies=no
> > -Requires=var-lib-nfs-rpc_pipefs.mount
> > -After=var-lib-nfs-rpc_pipefs.mount local-fs.target
> > +Requires=rpc_pipefs.target
> > +After=rpc_pipefs.target local-fs.target
> >  
> >  BindsTo=nfs-server.service
> >  
> > diff --git a/systemd/rpc-gssd.service.in b/systemd/rpc-gssd.service.in
> > index b353027..6807db3 100644
> > --- a/systemd/rpc-gssd.service.in
> > +++ b/systemd/rpc-gssd.service.in
> > @@ -2,8 +2,8 @@
> >  Description=RPC security service for NFS client and server
> >  DefaultDependencies=no
> >  Conflicts=umount.target
> > -Requires=var-lib-nfs-rpc_pipefs.mount
> > -After=var-lib-nfs-rpc_pipefs.mount
> > +Requires=rpc_pipefs.target
> > +After=rpc_pipefs.target
> >  
> >  ConditionPathExists=@_sysconfdir@/krb5.keytab
> >  
> > diff --git a/systemd/rpc-pipefs-generator.c b/systemd/rpc-pipefs-generator.c
> > new file mode 100644
> > index 0000000..b0a6c19
> > --- /dev/null
> > +++ b/systemd/rpc-pipefs-generator.c
> > @@ -0,0 +1,216 @@
> > +/*
> > + * rpc-pipefs-generator:
> > + *   systemd generator to create ordering dependencies between
> > + *   nfs services and the rpc_pipefs mountpoint
> > + */
> > +
> > +#ifdef HAVE_CONFIG_H
> > +#include <config.h>
> > +#endif
> > +
> > +#include <sys/stat.h>
> > +#include <sys/types.h>
> > +#include <unistd.h>
> > +#include <stdlib.h>
> > +#include <string.h>
> > +#include <ctype.h>
> > +#include <stdio.h>
> > +#include <mntent.h>
> > +
> > +#include "nfslib.h"
> > +#include "conffile.h"
> > +
> > +#define RPC_PIPEFS_DEFAULT "/var/lib/nfs/rpc_pipefs"
> > +char *conf_path = NFS_CONFFILE;
> > +
> > +int systemd_len(char *path)
> > +{
> > +	char *p;
> > +	int len = 0;
> > +
> > +	p = path;
> > +	while (*p == '/')
> > +		p++;
> > +
> > +	if (!*p)
> > +		/* "/" becomes "-", otherwise leading "/" is ignored */
> > +		return 1;
> > +
> > +	while (*p) {
> > +		unsigned char c = *p++;
> > +
> > +		if (c == '/') {
> > +			/* multiple non-trailing slashes become '-' */
> > +			while (*p == '/')
> > +				p++;
> > +			if (*p)
> > +				len++;
> > +		} else if (isalnum(c) || c == ':' || c == '.' || c == '_')
> > +			len++;
> > +		else {
> > +			len += 4;
> > +		}
> > +	}
> > +
> > +	return len;
> > +}
> > +
> > +char *systemd_escape(char *path)
> > +{
> > +	char *result = NULL;
> > +	char *p;
> > +	int len;
> > +
> > +	len = systemd_len(path);
> > +	if (!len)
> > +		goto out;
> > +
> > +	result = malloc(len + strlen(".mount") + 1);
> > +	if (!result)
> > +		goto out;
> > +
> > +	p = result;
> > +	while (*path == '/')
> > +		path++;
> > +	if (!*path) {
> > +		/* "/" becomes "-", otherwise leading "/" is ignored */
> > +		*p++ = '-';
> > +		goto out_append;
> > +	}
> > +	while (*path) {
> > +		unsigned char c = *path++;
> > +
> > +		if (c == '/') {
> > +			/* multiple non-trailing slashes become '-' */
> > +			while (*path == '/')
> > +				path++;
> > +			if (*path)
> > +				*p++ = '-';
> > +		} else if (isalnum(c) || c == ':' || c == '.' || c == '_')
> > +			*p++ = c;
> > +		else {
> > +			*p++ = '\\';
> > +			*p++ = 'x';
> > +			*p++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
> > +			*p++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
> > +		}
> > +	}
> > +
> > +out_append:
> > +	sprintf(p, ".mount");
> > +out:
> > +	return result;
> > +}
> > +
> > +static int generate_mount_unit(const char *pipefs_path, const char *pipefs_unit,
> > +			       const char *dirname)
> > +{
> > +	char	*path;
> > +	FILE	*f;
> > +
> > +	path = malloc(strlen(dirname) + 1 + strlen(pipefs_unit));
> > +	if (!path)
> > +		return 1;
> > +	sprintf(path, "%s/%s", dirname, pipefs_unit);
> > +	f = fopen(path, "w");
> > +	if (!f)
> > +		return 1;
> > +
> > +	fprintf(f, "# Automatically generated by rpc-pipefs-generator\n\n[Unit]\n");
> > +	fprintf(f, "Description=RPC Pipe File System\n");
> > +	fprintf(f, "DefaultDependencies=no\n");
> > +	fprintf(f, "After=systemd-tmpfiles-setup.service\n");
> > +	fprintf(f, "Conflicts=umount.target\n");
> > +	fprintf(f, "\n[Mount]\n");
> > +	fprintf(f, "What=sunrpc\n");
> > +	fprintf(f, "Where=%s\n", pipefs_path);
> > +	fprintf(f, "Type=rpc_pipefs\n");
> > +
> > +	fclose(f);
> > +	return 0;
> > +}
> > +
> > +static
> > +int generate_target(char *pipefs_path, const char *dirname)
> > +{
> > +	char	*path;
> > +	char	filebase[] = "/rpc_pipefs.target";
> > +	char	*pipefs_unit;
> > +	FILE	*f;
> > +	int 	ret = 0;
> > +
> > +	pipefs_unit = systemd_escape(pipefs_path);
> > +	if (!pipefs_unit)
> > +		return 1;
> > +
> > +	ret = generate_mount_unit(pipefs_path, pipefs_unit, dirname);
> > +	if (ret)
> > +		return ret;
> > +
> > +	path = malloc(strlen(dirname) + 1 + sizeof(filebase));
> > +	if (!path)
> > +		return 2;
> > +	sprintf(path, "%s", dirname);
> > +	mkdir(path, 0755);
> > +	strcat(path, filebase);
> > +	f = fopen(path, "w");
> > +	if (!f)
> > +		return 1;
> > +
> > +	fprintf(f, "# Automatically generated by rpc-pipefs-generator\n\n[Unit]\n");
> > +	fprintf(f, "Requires=%s\n", pipefs_unit);
> > +	fprintf(f, "After=%s\n", pipefs_unit);
> > +	fclose(f);
> > +
> > +	return 0;
> > +}
> > +
> > +static int is_non_pipefs_mountpoint(char *path)
> > +{
> > +	FILE		*mtab;
> > +	struct mntent	*mnt;
> > +
> > +	mtab = setmntent("/etc/mtab", "r");
> > +	if (!mtab)
> > +		return 0;
> > +
> > +	while ((mnt = getmntent(mtab)) != NULL) {
> > +		if (strlen(mnt->mnt_dir) != strlen(path))
> > +			continue;
> > +		if (strncmp(mnt->mnt_dir, path, strlen(mnt->mnt_dir)))
> > +			continue;
> > +		if (strncmp(mnt->mnt_type, "rpc_pipefs", strlen(mnt->mnt_type)))
> > +			break;
> > +	}
> > +	fclose(mtab);
> > +	return mnt != NULL;
> > +}
> > +
> > +int main(int argc, char *argv[])
> > +{
> > +	int 	ret;
> > +	char	*s;
> > +
> > +	/* Avoid using any external services */
> > +	xlog_syslog(0);
> > +
> > +	if (argc != 4 || argv[1][0] != '/') {
> > +		fprintf(stderr, "rpc-pipefs-generator: create systemd dependencies for nfs services\n");
> > +		fprintf(stderr, "Usage: normal-dir early-dir late-dir\n");
> > +		exit(1);
> > +	}
> > +
> > +	conf_init();
> > +	s = conf_get_str("global", "pipefs-directory");
> > +	if (!s)
> > +		exit(0);
> > +	if (strlen(s) == strlen(RPC_PIPEFS_DEFAULT) &&
> > +			strcmp(s, RPC_PIPEFS_DEFAULT) == 0)
> > +		exit(0);
> > +
> > +	if (is_non_pipefs_mountpoint(s))
> > +		exit(1);
> > +
> > +	ret = generate_target(s, argv[1]);
> > +	exit(ret);
> > +}
> > diff --git a/systemd/rpc-svcgssd.service b/systemd/rpc-svcgssd.service
> > index 7187e3c..cb2bcd4 100644
> > --- a/systemd/rpc-svcgssd.service
> > +++ b/systemd/rpc-svcgssd.service
> > @@ -1,8 +1,7 @@
> >  [Unit]
> >  Description=RPC security service for NFS server
> >  DefaultDependencies=no
> > -Requires=var-lib-nfs-rpc_pipefs.mount
> > -After=var-lib-nfs-rpc_pipefs.mount local-fs.target
> > +After=local-fs.target
> >  PartOf=nfs-server.service
> >  PartOf=nfs-utils.service
> >  
> > diff --git a/systemd/rpc_pipefs.target b/systemd/rpc_pipefs.target
> > new file mode 100644
> > index 0000000..01d4d27
> > --- /dev/null
> > +++ b/systemd/rpc_pipefs.target
> > @@ -0,0 +1,3 @@
> > +[Unit]
> > +Requires=var-lib-nfs-rpc_pipefs.mount
> > +After=var-lib-nfs-rpc_pipefs.mount
> > -- 
> > 2.9.3
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> > the body of a message to [e-mail]
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html


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NeilBrown April 6, 2017, 9:37 p.m. UTC | #4

On Thu, Apr 06 2017, Scott Mayhew wrote:

> On Thu, 06 Apr 2017, NeilBrown wrote:
>
>> On Wed, Apr 05 2017, Scott Mayhew wrote:
>> 
>> > The nfs.conf has config options for the rpc_pipefs mountpoint.
>> > Currently, changing these from the default also requires manually
>> > overriding the systemd unit files that are hard-coded to mount the
>> > filesystem on /var/lib/nfs/rpc_pipefs.
>> >
>> > This patch adds a generator that creates a mount unit file for the
>> > rpc_pipefs when a non-default value is specified in /etc/nfs.conf, as
>> > well as a target unit file to override the dependencies for the systemd
>> > units using the rpc_pipefs.  The blkmapd, idmapd, and gssd service unit
>> > files have been modified to define their dependencies on the rpc_pipefs
>> > mountpoint indirectly via the rpc_pipefs target unit file.
>> >
>> > This patch also removes the dependency on the rpc_pipefs from the
>> > rpc-svcgssd.service unit file.  rpc.svcgssd uses the sunrpc cache
>> > mechanism to exchange data with the kernel, not the rpc_pipefs.
>> >
>> > Signed-off-by: Scott Mayhew <[e-mail]>
>> 
>> I was reading through this, which I really thought would be a good patch
>> that I would give an Ack to, and looking at some of the detail involved,
>> I started to wonder if we were really doing the right thing here.
>> You go to some trouble to make the name of the .mount unit file match
>> the name of the location of the mountpoint.  Is that really necessary?
>> 
>> Unit files created by systemd-fstab-generator do follow that pattern,
>> but they don't have to.
>
>> 
>> Maybe we should just:
>> 
>> 1/ rename var-lib-nfs-rpc_pipefs.mount to rpc_pipefs.mount,
>>    and modify the dependencies accordingly.
>> 
> The mount doesn't work when I change the name.
>
> [root@fedora25 ~]# systemctl status rpc_pipefs.mount
> ● rpc_pipefs.mount - RPC Pipe File System
>    Loaded: error (Reason: Invalid argument)
>    Active: inactive (dead)
>     Where: /var/lib/nfs/rpc_pipefs
>      What: sunrpc
>
> Apr 06 08:17:59 localhost.localdomain systemd[1]: rpc_pipefs.mount: Where= setting doesn't match unit name. Refusing.
>
>
> Looking back at systemd.mount(5), it looks like they do have to follow
> that pattern:
>
>        Mount units must be named after the mount point directories they control.
>        Example: the mount point /home/lennart must be configured in a unit file
>        home-lennart.mount. For details about the escaping logic used to convert a
>        file system path to a unit name, see systemd.unit(5). Note that mount units
>        cannot be templated, nor is possible to add multiple names to a mount unit
>        by creating additional symlinks to it.
>

My turn not to read to the end of the man page I see...

That's a strange restriction that seem inconsistent with everything else
systemd does.  Maybe it it helpful for implementing "RequiresMountsFor"
but I cannot think of any other justification.
Anyway, I guess we have to live with it.

I bothered me that you needed to include this:
>> > +	fprintf(f, "DefaultDependencies=no\n");
>> > +	fprintf(f, "After=systemd-tmpfiles-setup.service\n");
>> > +	fprintf(f, "Conflicts=umount.target\n");

in the code, but I can't see anything we can do about that.

So:
 Reviewed-by: NeilBrown <[e-mail]>

for this patch.

Thanks,
NeilBrown

Patch

diff --git a/.gitignore b/.gitignore
index 126d12c..941aca0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -70,6 +70,7 @@  tests/nsm_client/nlm_sm_inter_svc.c
 tests/nsm_client/nlm_sm_inter_xdr.c
 utils/nfsidmap/nfsidmap
 systemd/nfs-server-generator
+systemd/rpc-pipefs-generator
 systemd/nfs-config.service
 systemd/rpc-gssd.service
 # cscope database files
diff --git a/systemd/Makefile.am b/systemd/Makefile.am
index 0d15b9f..4becb77 100644
--- a/systemd/Makefile.am
+++ b/systemd/Makefile.am
@@ -4,6 +4,7 @@  MAINTAINERCLEANFILES = Makefile.in
 
 unit_files =  \
     nfs-client.target \
+    rpc_pipefs.target \
     \
     nfs-mountd.service \
     nfs-server.service \
@@ -42,12 +43,14 @@  EXTRA_DIST = $(unit_files) $(man5_MANS) $(man7_MANS)
 unit_dir = /usr/lib/systemd/system
 generator_dir = /usr/lib/systemd/system-generators
 
-EXTRA_PROGRAMS	= nfs-server-generator
+EXTRA_PROGRAMS	= nfs-server-generator rpc-pipefs-generator
 genexecdir = $(generator_dir)
 nfs_server_generator_LDADD = ../support/export/libexport.a \
 			     ../support/nfs/libnfs.a \
 			     ../support/misc/libmisc.a
 
+rpc_pipefs_generator_LDADD = ../support/nfs/libnfs.a
+
 if INSTALL_SYSTEMD
 genexec_PROGRAMS = nfs-server-generator
 install-data-hook: $(unit_files)
diff --git a/systemd/nfs-blkmap.service b/systemd/nfs-blkmap.service
index ddc324e..2bbcee6 100644
--- a/systemd/nfs-blkmap.service
+++ b/systemd/nfs-blkmap.service
@@ -2,8 +2,8 @@ 
 Description=pNFS block layout mapping daemon
 DefaultDependencies=no
 Conflicts=umount.target
-After=var-lib-nfs-rpc_pipefs.mount
-Requires=var-lib-nfs-rpc_pipefs.mount
+After=rpc_pipefs.target
+Requires=rpc_pipefs.target
 
 PartOf=nfs-utils.service
 
diff --git a/systemd/nfs-idmapd.service b/systemd/nfs-idmapd.service
index acca86b..f38fe52 100644
--- a/systemd/nfs-idmapd.service
+++ b/systemd/nfs-idmapd.service
@@ -1,8 +1,8 @@ 
 [Unit]
 Description=NFSv4 ID-name mapping service
 DefaultDependencies=no
-Requires=var-lib-nfs-rpc_pipefs.mount
-After=var-lib-nfs-rpc_pipefs.mount local-fs.target
+Requires=rpc_pipefs.target
+After=rpc_pipefs.target local-fs.target
 
 BindsTo=nfs-server.service
 
diff --git a/systemd/rpc-gssd.service.in b/systemd/rpc-gssd.service.in
index b353027..6807db3 100644
--- a/systemd/rpc-gssd.service.in
+++ b/systemd/rpc-gssd.service.in
@@ -2,8 +2,8 @@ 
 Description=RPC security service for NFS client and server
 DefaultDependencies=no
 Conflicts=umount.target
-Requires=var-lib-nfs-rpc_pipefs.mount
-After=var-lib-nfs-rpc_pipefs.mount
+Requires=rpc_pipefs.target
+After=rpc_pipefs.target
 
 ConditionPathExists=@_sysconfdir@/krb5.keytab
 
diff --git a/systemd/rpc-pipefs-generator.c b/systemd/rpc-pipefs-generator.c
new file mode 100644
index 0000000..b0a6c19
--- /dev/null
+++ b/systemd/rpc-pipefs-generator.c
@@ -0,0 +1,216 @@ 
+/*
+ * rpc-pipefs-generator:
+ *   systemd generator to create ordering dependencies between
+ *   nfs services and the rpc_pipefs mountpoint
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <stdio.h>
+#include <mntent.h>
+
+#include "nfslib.h"
+#include "conffile.h"
+
+#define RPC_PIPEFS_DEFAULT "/var/lib/nfs/rpc_pipefs"
+char *conf_path = NFS_CONFFILE;
+
+int systemd_len(char *path)
+{
+	char *p;
+	int len = 0;
+
+	p = path;
+	while (*p == '/')
+		p++;
+
+	if (!*p)
+		/* "/" becomes "-", otherwise leading "/" is ignored */
+		return 1;
+
+	while (*p) {
+		unsigned char c = *p++;
+
+		if (c == '/') {
+			/* multiple non-trailing slashes become '-' */
+			while (*p == '/')
+				p++;
+			if (*p)
+				len++;
+		} else if (isalnum(c) || c == ':' || c == '.' || c == '_')
+			len++;
+		else {
+			len += 4;
+		}
+	}
+
+	return len;
+}
+
+char *systemd_escape(char *path)
+{
+	char *result = NULL;
+	char *p;
+	int len;
+
+	len = systemd_len(path);
+	if (!len)
+		goto out;
+
+	result = malloc(len + strlen(".mount") + 1);
+	if (!result)
+		goto out;
+
+	p = result;
+	while (*path == '/')
+		path++;
+	if (!*path) {
+		/* "/" becomes "-", otherwise leading "/" is ignored */
+		*p++ = '-';
+		goto out_append;
+	}
+	while (*path) {
+		unsigned char c = *path++;
+
+		if (c == '/') {
+			/* multiple non-trailing slashes become '-' */
+			while (*path == '/')
+				path++;
+			if (*path)
+				*p++ = '-';
+		} else if (isalnum(c) || c == ':' || c == '.' || c == '_')
+			*p++ = c;
+		else {
+			*p++ = '\\';
+			*p++ = 'x';
+			*p++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
+			*p++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
+		}
+	}
+
+out_append:
+	sprintf(p, ".mount");
+out:
+	return result;
+}
+
+static int generate_mount_unit(const char *pipefs_path, const char *pipefs_unit,
+			       const char *dirname)
+{
+	char	*path;
+	FILE	*f;
+
+	path = malloc(strlen(dirname) + 1 + strlen(pipefs_unit));
+	if (!path)
+		return 1;
+	sprintf(path, "%s/%s", dirname, pipefs_unit);
+	f = fopen(path, "w");
+	if (!f)
+		return 1;
+
+	fprintf(f, "# Automatically generated by rpc-pipefs-generator\n\n[Unit]\n");
+	fprintf(f, "Description=RPC Pipe File System\n");
+	fprintf(f, "DefaultDependencies=no\n");
+	fprintf(f, "After=systemd-tmpfiles-setup.service\n");
+	fprintf(f, "Conflicts=umount.target\n");
+	fprintf(f, "\n[Mount]\n");
+	fprintf(f, "What=sunrpc\n");
+	fprintf(f, "Where=%s\n", pipefs_path);
+	fprintf(f, "Type=rpc_pipefs\n");
+
+	fclose(f);
+	return 0;
+}
+
+static
+int generate_target(char *pipefs_path, const char *dirname)
+{
+	char	*path;
+	char	filebase[] = "/rpc_pipefs.target";
+	char	*pipefs_unit;
+	FILE	*f;
+	int 	ret = 0;
+
+	pipefs_unit = systemd_escape(pipefs_path);
+	if (!pipefs_unit)
+		return 1;
+
+	ret = generate_mount_unit(pipefs_path, pipefs_unit, dirname);
+	if (ret)
+		return ret;
+
+	path = malloc(strlen(dirname) + 1 + sizeof(filebase));
+	if (!path)
+		return 2;
+	sprintf(path, "%s", dirname);
+	mkdir(path, 0755);
+	strcat(path, filebase);
+	f = fopen(path, "w");
+	if (!f)
+		return 1;
+
+	fprintf(f, "# Automatically generated by rpc-pipefs-generator\n\n[Unit]\n");
+	fprintf(f, "Requires=%s\n", pipefs_unit);
+	fprintf(f, "After=%s\n", pipefs_unit);
+	fclose(f);
+
+	return 0;
+}
+
+static int is_non_pipefs_mountpoint(char *path)
+{
+	FILE		*mtab;
+	struct mntent	*mnt;
+
+	mtab = setmntent("/etc/mtab", "r");
+	if (!mtab)
+		return 0;
+
+	while ((mnt = getmntent(mtab)) != NULL) {
+		if (strlen(mnt->mnt_dir) != strlen(path))
+			continue;
+		if (strncmp(mnt->mnt_dir, path, strlen(mnt->mnt_dir)))
+			continue;
+		if (strncmp(mnt->mnt_type, "rpc_pipefs", strlen(mnt->mnt_type)))
+			break;
+	}
+	fclose(mtab);
+	return mnt != NULL;
+}
+
+int main(int argc, char *argv[])
+{
+	int 	ret;
+	char	*s;
+
+	/* Avoid using any external services */
+	xlog_syslog(0);
+
+	if (argc != 4 || argv[1][0] != '/') {
+		fprintf(stderr, "rpc-pipefs-generator: create systemd dependencies for nfs services\n");
+		fprintf(stderr, "Usage: normal-dir early-dir late-dir\n");
+		exit(1);
+	}
+
+	conf_init();
+	s = conf_get_str("global", "pipefs-directory");
+	if (!s)
+		exit(0);
+	if (strlen(s) == strlen(RPC_PIPEFS_DEFAULT) &&
+			strcmp(s, RPC_PIPEFS_DEFAULT) == 0)
+		exit(0);
+
+	if (is_non_pipefs_mountpoint(s))
+		exit(1);
+
+	ret = generate_target(s, argv[1]);
+	exit(ret);
+}
diff --git a/systemd/rpc-svcgssd.service b/systemd/rpc-svcgssd.service
index 7187e3c..cb2bcd4 100644
--- a/systemd/rpc-svcgssd.service
+++ b/systemd/rpc-svcgssd.service
@@ -1,8 +1,7 @@ 
 [Unit]
 Description=RPC security service for NFS server
 DefaultDependencies=no
-Requires=var-lib-nfs-rpc_pipefs.mount
-After=var-lib-nfs-rpc_pipefs.mount local-fs.target
+After=local-fs.target
 PartOf=nfs-server.service
 PartOf=nfs-utils.service
 
diff --git a/systemd/rpc_pipefs.target b/systemd/rpc_pipefs.target
new file mode 100644
index 0000000..01d4d27
--- /dev/null
+++ b/systemd/rpc_pipefs.target
@@ -0,0 +1,3 @@ 
+[Unit]
+Requires=var-lib-nfs-rpc_pipefs.mount
+After=var-lib-nfs-rpc_pipefs.mount