Bruce suggested, years ago, that the nfsref command should become
the premier administrative interface for managing NFSD's referral
behavior.
Towards that end, some clean-up is needed for the nfsref command in
nfs-utils, which is presented for review here.
I'm hesitant to introduce more documentation at this time for the
refer= and replica= export options if we plan to remove them in the
medium term.
---
Chuck Lever (5):
junction: Replace xmlParseMemory
junction: Remove xmlIndentTreeOutput
nfsref: Remove unneeded #include in utils/nfsref/nfsref.c
nfsref: Improve nfsref(5)
configure: Make --enable-junction=yes the default
configure.ac | 6 ++---
support/junction/xml.c | 3 +--
utils/nfsref/nfsref.c | 2 --
utils/nfsref/nfsref.man | 60 +++++++++++++++++++++--------------------
4 files changed, 35 insertions(+), 36 deletions(-)
--
Chuck Lever
From: Chuck Lever <[email protected]>
According to:
https://gnome.pages.gitlab.gnome.org/libxml2/devhelp/libxml2-parser.html#xmlParseMemory
xmlParseMemory() is deprecated. Replace the one call site with a
call to xmlReadMemory().
Signed-off-by: Chuck Lever <[email protected]>
---
support/junction/xml.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/support/junction/xml.c b/support/junction/xml.c
index 813110b4f308..ec9586528cc9 100644
--- a/support/junction/xml.c
+++ b/support/junction/xml.c
@@ -290,7 +290,7 @@ junction_parse_xml_buf(const char *pathname, const char *name,
{
xmlDocPtr tmp;
- tmp = xmlParseMemory(buf, (int)len);
+ tmp = xmlReadMemory(buf, (int)len, NULL, NULL, 0);
if (tmp == NULL) {
xlog(D_GENERAL, "Failed to parse XML in %s(%s)\n",
pathname, name);
From: Chuck Lever <[email protected]>
Though it doesn't seem to be marked deprecated, xmlIndentTreeOutput
does not appear in recent versions of libxml2. Since
xmlIndentTreeOutput = 1;
should be the default behavior now, we can remove this statement
without a behavior change.
Signed-off-by: Chuck Lever <[email protected]>
---
support/junction/xml.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/support/junction/xml.c b/support/junction/xml.c
index ec9586528cc9..aef1cbbd74d3 100644
--- a/support/junction/xml.c
+++ b/support/junction/xml.c
@@ -387,7 +387,6 @@ junction_xml_write(const char *pathname, const char *name, xmlDocPtr doc)
return retval;
retval = FEDFS_ERR_SVRFAULT;
- xmlIndentTreeOutput = 1;
xmlDocDumpFormatMemoryEnc(doc, &buf, &len, "UTF-8", 1);
if (len < 0)
goto out;
From: Chuck Lever <[email protected]>
Neil Brown says:
> The only thing that was interesting is that nfsref.c includes
> sys/capability.h, and I didn't have libcap declared as BuildRequires.
> The ./configure script didn't complain that libcap was missing - instead
> the build failed.
>
> Other places in nfs-utils that include capability.h protect it with
> #ifdef HAVE_SYS_CAPABILITY_H
>
> If nfsref.c followed that pattern I wouldn't have received an error.
> But then I wouldn't have added a dependency on libcap.
> Do I really want libcap?? I don't know.
> But I cannot see where nfsref.c uses libcap or prctl. So maybe
> those includes aren't needed.
Signed-off-by: Chuck Lever <[email protected]>
---
utils/nfsref/nfsref.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/utils/nfsref/nfsref.c b/utils/nfsref/nfsref.c
index 7f97d01f55ca..aa8414b425fb 100644
--- a/utils/nfsref/nfsref.c
+++ b/utils/nfsref/nfsref.c
@@ -24,8 +24,6 @@
*/
#include <sys/types.h>
-#include <sys/capability.h>
-#include <sys/prctl.h>
#include <sys/stat.h>
#include <stdbool.h>
From: Chuck Lever <[email protected]>
Neil Brown says:
> ... I found the man page a bit confusing. It starts off talking about
> "referrals", which are suitably defined. Then drifts into talking about
> "junctions" which might be the same thing, but aren't defined.
>
> The intro suggests that the admin can use "refer=" in /etc/exports, but
> doesn't say why they might want to use "nfsref" instead, or how the two
> relate.
>
> Description says "Other administrative commands provide richer access to
> junction information." but there are no pointers in "See Also".
>
> The --type option, we are told, can specify nfs-fedfs but there is no
> further mention of this, or any pointers to more info. Maybe add
> "(deprecated)"??
Signed-off-by: Chuck Lever <[email protected]>
---
utils/nfsref/nfsref.man | 60 ++++++++++++++++++++++++-----------------------
1 file changed, 31 insertions(+), 29 deletions(-)
diff --git a/utils/nfsref/nfsref.man b/utils/nfsref/nfsref.man
index 12615497a404..1970f9dd4144 100644
--- a/utils/nfsref/nfsref.man
+++ b/utils/nfsref/nfsref.man
@@ -53,33 +53,37 @@ nfsref \- manage NFS referrals
NFS version 4 introduces the concept of
.I file system referrals
to NFS.
-A file system referral is like a symbolic link on a file server
-to another file system share, possibly on another file server.
-On an NFS client, a referral behaves like an automounted directory.
-The client, under the server's direction, mounts a new NFS export
-automatically when an application first accesses that directory.
.P
-Referrals are typically used to construct a single file name space
-across multiple file servers.
-Because file servers control the shape of the name space,
-no client configuration is required,
-and all clients see the same referral information.
+A file system referral is like a symbolic link
+(or,
+.IR symlink )
+to another file system share, typically on another file server.
+An NFS client, under the server's direction,
+mounts the referred-to NFS export
+automatically when an application first accesses it.
.P
-The Linux NFS server supports NFS version 4 referrals.
-Administrators can specify the
-.B refer=
-export option in
-.I /etc/exports
-to configure a list of exports from which the client can choose.
-See
-.BR exports (5)
-for details.
+NFSv4 referrals can be used to transparently redirect clients
+to file systems that have been moved elsewhere, or
+to construct a single file name space across multiple file servers.
+Because file servers control the shape of the whole file name space,
+no client configuration is required.
.P
.SH DESCRIPTION
+A
+.I junction
+is a file system object on an NFS server that,
+when an NFS client encounters it, triggers a referral.
+Similar to a symlink, a junction contains one or more target locations
+that the server sends to clients in the form of an NFSv4 referral.
+.P
+On Linux, an existing directory can be converted to a junction
+and back atomically and without the loss of the directory contents.
+When a directory acts as a junction, it's local content is hidden
+from NFSv4 clients.
+.P
The
.BR nfsref (8)
-command is a simple way to get started managing junction metadata.
-Other administrative commands provide richer access to junction information.
+command is a simple way to get started managing junctions and their content.
.SS Subcommands
Valid
.BR nfsref (8)
@@ -135,6 +139,10 @@ For the
.B add
subcommand, the default value if this option is not specified is
.BR nfs-basic .
+The
+.B nfs-fedfs
+type is not used in this implementation.
+.IP
For the
.B remove
and
@@ -163,18 +171,12 @@ you might issue this command as root:
.sp
# mkdir /home
.br
-# nfsref --type=nfs-basic add /home home.example.net /
+# nfsref add /home home.example.net /
.br
Created junction /home.
.sp
.RE
-.SH FILES
-.TP
-.I /etc/exports
-NFS server export table
.SH "SEE ALSO"
-.BR exports (5)
-.sp
-RFC 5661 for a description of NFS version 4 referrals
+RFC 8881 for a description of the NFS version 4 referral mechanism
.SH "AUTHOR"
Chuck Lever <[email protected]>
From: Chuck Lever <[email protected]>
When I first introduced the nfsref command as part of fedfs-utils,
Bruce suggested that we should adopt nfsref as the mechanism for
managing NFSv4 referrals, over the existing refer= and replica=
export options.
Now that nfsref has been an integral part of nfs-utils for several
years, it's time to take the next step toward that goal: ensure that
the nfsref command (and the appropriate logic inside of mountd) is
built and available by default.
Signed-off-by: Chuck Lever <[email protected]>
---
configure.ac | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/configure.ac b/configure.ac
index 4ade528d72e8..e95075671571 100644
--- a/configure.ac
+++ b/configure.ac
@@ -175,14 +175,14 @@ else
fi
AC_ARG_ENABLE(sbin-override,
- [AS_HELP_STRING([--disable-sbin-override],[Don't force nfsdcltrack and mount helpers into /sbin: always honour --sbindir])],
+ [AS_HELP_STRING([--disable-sbin-override],[Do not force nfsdcltrack and mount helpers into /sbin: always honour --sbindir])],
enable_sbin_override=$enableval,
enable_sbin_override=yes)
AM_CONDITIONAL(CONFIG_SBIN_OVERRIDE, [test "$enable_sbin_override" = "yes"])
AC_ARG_ENABLE(junction,
- [AS_HELP_STRING([--enable-junction],[enable support for NFS junctions @<:@default=no@:>@])],
+ [AS_HELP_STRING([--enable-junction],[enable support for NFS junctions @<:@default=yes@:>@])],
enable_junction=$enableval,
- enable_junction=no)
+ enable_junction=yes)
if test "$enable_junction" = yes; then
AC_DEFINE(HAVE_JUNCTION_SUPPORT, 1,
[Define this if you want junction support compiled in])
> On Nov 20, 2023, at 1:53 PM, Chuck Lever <[email protected]> wrote:
>
> Bruce suggested, years ago, that the nfsref command should become
> the premier administrative interface for managing NFSD's referral
> behavior.
>
> Towards that end, some clean-up is needed for the nfsref command in
> nfs-utils, which is presented for review here.
I forgot to mention: the series is marked RFC because they are
compile-tested only.
> I'm hesitant to introduce more documentation at this time for the
> refer= and replica= export options if we plan to remove them in the
> medium term.
>
> ---
>
> Chuck Lever (5):
> junction: Replace xmlParseMemory
> junction: Remove xmlIndentTreeOutput
> nfsref: Remove unneeded #include in utils/nfsref/nfsref.c
> nfsref: Improve nfsref(5)
> configure: Make --enable-junction=yes the default
>
>
> configure.ac | 6 ++---
> support/junction/xml.c | 3 +--
> utils/nfsref/nfsref.c | 2 --
> utils/nfsref/nfsref.man | 60 +++++++++++++++++++++--------------------
> 4 files changed, 35 insertions(+), 36 deletions(-)
>
> --
> Chuck Lever
>
--
Chuck Lever
> On Nov 20, 2023, at 1:58 PM, Chuck Lever III <[email protected]> wrote:
>
>
>
>> On Nov 20, 2023, at 1:53 PM, Chuck Lever <[email protected]> wrote:
>>
>> Bruce suggested, years ago, that the nfsref command should become
>> the premier administrative interface for managing NFSD's referral
>> behavior.
>>
>> Towards that end, some clean-up is needed for the nfsref command in
>> nfs-utils, which is presented for review here.
>
> I forgot to mention: the series is marked RFC because they are
> compile-tested only.
I've done some limited testing now. These seem to work.
>> I'm hesitant to introduce more documentation at this time for the
>> refer= and replica= export options if we plan to remove them in the
>> medium term.
>>
>> ---
>>
>> Chuck Lever (5):
>> junction: Replace xmlParseMemory
>> junction: Remove xmlIndentTreeOutput
>> nfsref: Remove unneeded #include in utils/nfsref/nfsref.c
>> nfsref: Improve nfsref(5)
>> configure: Make --enable-junction=yes the default
>>
>>
>> configure.ac | 6 ++---
>> support/junction/xml.c | 3 +--
>> utils/nfsref/nfsref.c | 2 --
>> utils/nfsref/nfsref.man | 60 +++++++++++++++++++++--------------------
>> 4 files changed, 35 insertions(+), 36 deletions(-)
>>
>> --
>> Chuck Lever
>>
>
> --
> Chuck Lever
>
>
--
Chuck Lever
On 11/20/23 1:53 PM, Chuck Lever wrote:
> Bruce suggested, years ago, that the nfsref command should become
> the premier administrative interface for managing NFSD's referral
> behavior.
>
> Towards that end, some clean-up is needed for the nfsref command in
> nfs-utils, which is presented for review here.
>
> I'm hesitant to introduce more documentation at this time for the
> refer= and replica= export options if we plan to remove them in the
> medium term.
>
> ---
>
> Chuck Lever (5):
> junction: Replace xmlParseMemory
> junction: Remove xmlIndentTreeOutput
> nfsref: Remove unneeded #include in utils/nfsref/nfsref.c
> nfsref: Improve nfsref(5)
> configure: Make --enable-junction=yes the default
>
>
> configure.ac | 6 ++---
> support/junction/xml.c | 3 +--
> utils/nfsref/nfsref.c | 2 --
> utils/nfsref/nfsref.man | 60 +++++++++++++++++++++--------------------
> 4 files changed, 35 insertions(+), 36 deletions(-)
>
> --
> Chuck Lever
>
Committed... (tag: nfs-utils-2-7-1-rc2)
steved.