Provided by: nfs-ganesha_4.0.8-2_amd64 bug

NAME

       ganesha-export-config - NFS Ganesha Export Configuration File

SYNOPSIS

          /etc/ganesha/ganesha.conf

DESCRIPTION

       NFS-Ganesha obtains configuration data from the configuration file:
          /etc/ganesha/ganesha.conf

       This file lists NFS-Ganesha Export block config options.

   EXPORT_DEFAULTS {}
       These  options are all "export permissions" options, and will be repeated in the EXPORT {}
       and EXPORT { CLIENT {} } blocks.

       These options will all be dynamically updateable.

       Access_Type(enum, default None)

              Possible values:
                     None, RW, RO, MDONLY, MDONLY_RO

       Protocols(enum list, default [3,4])

              Possible values:
                     3, 4, NFS3, NFS4, V3, V4, NFSv3, NFSv4, 9P

       Transports(enum list, values [UDP, TCP, RDMA], default [UDP, TCP])

       Anonymous_uid(anonid, range INT32_MIN to UINT32_MAX, default -2)

       Anonymous_gid(anonid, range INT32_MIN to UINT32_MAX, default -2)

       SecType(enum list, default [none, sys])

              Possible values:
                     none, sys, krb5, krb5i, krb5p

       PrivilegedPort(bool, default false)

       Manage_Gids(bool, default false)

       Squash(enum, default root_sqaush)

              Possible values:
                     root, root_squash, rootsquash, rootid,  root_id_squash,  rootidsquash,  all,
                     all_squash,  allsquash,  all_anomnymous, allanonymous, no_root_squash, none,
                     noidsquash

              Each line of defaults above are synonyms

       Security_Label(bool, default false)

       NFS_Commit(bool, default false)

       Delegations(enum, default None)

              Possible values:
                     None, read, write, readwrite, r, w, rw

       Attr_Expiration_Time(int32, range -1 to INT32_MAX, default 60)

   EXPORT {}
       All options below are dynamically changeable with config update unless specified below.

       Export_id (required):
              An identifier for the export, must be unique and between 0 and 65535.  If Export_Id
              0 is specified, Pseudo must be the root path (/).

              Export_id is not dynamic per se, changing it essentially removes the old export and
              introduces a new export.

       Path (required)
              The directory in the exported file system this export is rooted on (may be  ignored
              for some FSALs). It need not be unique if Pseudo and/or Tag are specified.

              Note  that  if  it  is not unique, and the core option mount_path_pseudo is not set
              true, a v3 mount using the path will ONLY  be  able  to  access  the  first  export
              configured. To access other exports the Tag option would need to be used.

              This  option  is  NOT  dynamically  updateable  since  it fundamentally changes the
              export. To change the path exported, export_id should be changed also.

       Pseudo (required v4)
              This option specifies the position in the Pseudo Filesystem this export occupies if
              this is an NFS v4 export. It must be unique. By using different Pseudo options, the
              same Path may be exported multiple times.

              This option is used to place the export within the NFS v4 Pseudo  Filesystem.  This
              creates  a  single  name space for NFS v4. Clients may mount the root of the Pseudo
              Filesystem and navigate to exports.  Note that the Path and Tag options are not  at
              all visible to NFS v4 clients.

              Export  id  0  is  automatically  created  to  provide the root and any directories
              necessary to navigate to exports if there is no other export specified with  Pseudo
              =  /;.  Note that if an export is specified with Pseudo = /;, it need not be export
              id 0. Specifying such an export with FSAL { name = PSEUDO; } may be used to  create
              a  Pseudo Filesystem with specific options. Such an export may also use other FSALs
              (though directories to reach exports will ONLY be  automatically  created  on  FSAL
              PSEUDO exports).

              This  option  is dynamically changeable and changing it will move the export within
              the pseudo filesystem. This  may  be  disruptive  to  clients.  Note  that  if  the
              mount_path_pseudo  NFS_CORE_PARAM  option  is  true, the NFSv3 mount path will also
              change (that should not be disruptive to clients that have the export mounted).

       Tag (no default)
              This option allows an alternative access for NFS v3 mounts.  The  option  MUST  not
              have  a  leading  /.  Clients  may not mount subdirectories (i.e. if Tag = foo, the
              client may not mount foo/baz). By using different Tag options, the same Path may be
              exported multiple times.

              This option is not dynamically updatable.

       MaxRead (64*1024*1024)
              The maximum read size on this export

       MaxWrite (64*1024*1024)
              The maximum write size on this export

       PrefRead (64*1024*1024)
              The  preferred  read  size  on  this  export. Note that some older nfs client (e.g.
              libnfs 1.x) would not handle well for large preferred read size. If so, please  try
              to decrease this size (usually less than 1M is suitable for older nfs client).

       PrefWrite (64*1024*1024)
              The  preferred  write  size  on  this export. Note that some older nfs client (e.g.
              libnfs 1.x) would not handle well for large preferred write size. If so, please try
              to decrease this size (usually less than 1M is suitable for older nfs client).

       PrefReaddir (16384)
              The preferred readdir size on this export

       MaxOffsetWrite (INT64_MAX)
              Maximum file offset that may be written Range is 512 to UINT64_MAX

       MaxOffsetRead (INT64_MAX)
              Maximum file offset that may be read Range is 512 to UINT64_MAX

       CLIENT (optional)
              See the EXPORT { CLIENT  {} } block.

       FSAL (required)
              See the EXPORT { FSAL  {} } block.

              The FSAL for an export can not be changed dynamically. In order to change the FSAL,
              a new export must be created.

              At this time, no FSAL actually supports any updatable options.

   EXPORT { CLIENT {} }
       Take all the "export permissions" options from  EXPORT_DEFAULTS.   The  client  lists  are
       dynamically updateable.

       These  blocks  form  an  ordered  "access control list" for the export. If no client block
       matches for a particular client, then the permissions in the EXPORT {} block will be used.

       Even when a CLIENT block matches a client,  if  a  particular  export  permission  is  not
       explicit  in that CLIENT block, the permission specified in the EXPORT block will be used,
       or if not specified there, from the EXPORT_DEFAULTS block, and if not specified there, the
       permission  will  default  to  the  default  code  value  noted  in  the permission option
       descriptions above.

       Note that when the CLIENT blocks are processed on config reload, a new client access  list
       is  constructed  and atomically swapped in. This allows adding, removing, and re-arranging
       clients as well as changing the access for any give client.

       Clients(client list, empty)
              Client list entries can take on one of the following forms: Match any client:

                 @name       Netgroup name
                 x.x.x.x/y   IPv4 network address
                 wildcarded  If the string contains at least one ? or *
                             character (and is not simply "*"), the string is
                             used to pattern match host names. Note that [] may
                             also be used, but the pattern MUST have at least one
                             ? or *
                 hostname    Match a single client (match is by IP address, all
                             addresses returned by getaddrinfo will match, the
                             getaddrinfo call is made at config parsing time)
                 IP address  Match a single client

   EXPORT { FSAL {} }
       NFS-Ganesha supports the following FSALs: Ceph Gluster GPFS PROXY_V3 PROXY_V4 RGW VFS  XFS
       LUSTRE LIzardFS KVSFS

       Refer to individual FSAL config file for list of config options.

       The FSAL blocks generally are less updatable

DISCUSSION

       The EXPORT blocks define the file namespaces that are served by NFS-Ganesha.

       In  best  practice,  each  underlying  filesystem  has  a  single EXPORT defining how that
       filesystem is to be shared, however, in some  cases,  it  is  desirable  to  sub-divide  a
       filesystem  into  multiple exports. The danger when this is done is that rogue clients may
       be able to spoof file handles and access portions of the filesystem  not  intended  to  be
       accessible to that client.

       Some FSALs (currently FSAL_VFS, FSAL_GPFS, FSAL_XFS, and FSAL_LUSTRE) are built to support
       nested filesystems, for example:
          /export/fs1 /export/fs1/some/path/fs2

       In this case, it is possible to create a single  export  that  exports  both  filesystems.
       There is a lot of complexity of what can be done there.

       In discussions of filesystems, btrfs filesystems exported by FSAL_VFS may have subvolumes.
       Starting in NFS-Ganesha V4.0 FSAL_VFS  treats  these  as  separate  filesystems  that  are
       integrated with all the richness of FSAL_VFS exports.

       Another  significant  FSAL  from  an  export point of view is FSAL_PSEUDO. This is used to
       build glue exports to build the unified NFSv4 name space. This name space may also be used
       by NFSv3 by setting the NFS_CORE_PARAM option:
          mount_path_pseudo = TRUE;

       If no FSAL_PSEUDO export is explicitly defined, and there is no EXPORT with:
          Pseudo = "/";

       NFS-Ganesha  will  build  a  FSAL_PSEUDO EXPORT with this Pseudo Path using Export_Id = 0.
       This automatic EXPORT may be  replaced  with  an  explicit  EXPORT  which  need  not  have
       Export_Id = 0, it just must have Pseudo = "/" and Protocols = 4.

       In  building the Pseudo Filesystem, there is a subtle gotcha. Since NFSv4 clients actually
       moount the root of the Pseudo Filesystem and then use LOOKUP to traverse into  the  actual
       directory  the  sysadmin  has mounted from the client, any EXPORTs from "/" to the desired
       EXPORT MUST have Protocols = 4 specified either  in  EXPORT_DEFAULTS  {},  EXPORT  {},  or
       EXPORT  {  CLIENT  {}  }.   This  is to assure that the client is allowed to traverse each
       EXPORT.

       If Mount_Path_Pseudo = TRUE is being used and an export  is  desired  to  be  NFSv3  only,
       Protocols  =  3 MUST be specified in the EXPORT {} block. If Protocols is not specified in
       the EXPORT {} block and is only specified in an EXPORT { CLIENT  {}  }  block,  then  that
       export  will  still be mounted in the Pseudo Filesystem but might not be traversable. Thus
       if the following two filesystems are exported:
          /export/fs1 /export/fs1/some/path/fs2

       And the EXPORTs look something like this:
          EXPORT {
              Export_Id = 1; Path = /export/fs1; Peudo = /export/fs1;

              FSAL {
                 Name = VFS;

              }

              CLIENT {
                 Clients="*"; Protocols=3;

              }

          }

          EXPORT {
              Export_Id = 1; Path = /export/fs1/some/path/fs2; Peudo = /export/fs1/some/path/fs2;

              FSAL {
                 Name = VFS;

              }

              CLIENT {
                 Clients="*"; Protocols=3,4;

              }

          }

       NFSv4 clients will not be able to access /export/fs1/some/path/fs2.  The  correct  way  to
       accomplish this is:
          EXPORT {
                 Export_Id = 1; Path = /export/fs1; Peudo = /export/fs1; Protocols=3;

              FSAL

                     {      Name = VFS;

                     }

          }

       Note that an EXPORT { CLIENT {} } block is not necessary if the default export permissions
       are workable.

       Note that in order for an EXPORT to be usable with NSFv4 it MUST either have Protocols = 4
       specified  in  the EXPORT block, or the EXPORT block must not have the Protocols option at
       all such that it defaults to 3,4,9P. Note though that if it is not set and EXPORT_DEFAULTS
       just  has  Protocols = 3; then even though the export is mounted in the Pseudo Filesystem,
       it will not be accessible and the gotcha discussed above may be in play.

CONFIGURATION RELOAD

       In addition to the LOG {} configuration, EXPORT {} config is the main  configuration  that
       can be updated while NFS-Ganesha is running by issuing a SIGHUP.

       This  causes  all  EXPORT  and EXPORT_DEFAULTS blocks to be reloaded. NFS-Ganesha V4.0 and
       later have some significant improvements to this since it was  introduced  in  NFS-Ganesha
       V2.4.0. V2.8.0 introduced the ability to remove EXPORTs via SIGHUP configuration reload.

       Significantly how things work now is:

       On  SIGHUP  all  the  EXPORT  and  EXPORT_DEFAULTS  blocks  are  re-read.  There are three
       conditions that may occur:
          An export may be added An export may be removed An export may be updated

       A note on Export_Id and Path. These are the primary options  that  define  an  export.  If
       Export_Id  is  changed,  the  change  is  treated  as a remove of the old Export_Id and an
       addition of the new Export_Id. Path can not be changed without  also  changing  Export_Id.
       The  Tag  and  Pseudo  options  that also contribute to the uniqueness of an EXPORT may be
       changed.

       Any removed exports are removed from the internal tables and if they  are  NFSv4  exports,
       unmounted  from the Pseudo Filesystem, which will then be re-built as if those exports had
       not been present.

       Any new exports are added to the internal tables, and if the export is  an  NFSv4  export,
       they are mounted into the Pseudo Filesystem.

       Any  updated  exports  will  be modified with the least disruption possible. If the Pseduo
       option is changed, the export is unmounted from the Pseduo  Filesystem  in  it's  original
       location,  and  re-mounted  in  it's  new  location. Other options are updated atomically,
       though serially, so for a short period of time, the options may be mixed between  old  and
       new.  In most cases this should not cause problems.  Notably though, the CLIENT blocks are
       processed to form a new access control list and that list is atomically swapped  with  the
       old  list.  If  the  Protocols  for  an EXPORT are changed to include or remove NFSv4, the
       Pseduo Filesystem will also be updated.

       Note that there is no pause in operations other than a lock being taken  when  the  client
       list  is  being  swapped  out,  however the export permissions are applied to an operation
       once. Notably for NFSv4, this is on a PUTFH or  LOOKUP  which  changes  the  Current  File
       Handle.  As an example, if a write is in progress, having passed the permission check with
       the previous export permissions, the write will  complete  without  interruption.  If  the
       write  is part of an NFSv4 COMPOUND, the other operations in that COMPOUND that operate on
       the same file handle will also complete with the previous export permissions.

       An update of EXPORT_DEFAULTS changes the export options atomically. These options are only
       used  for  those  options  not  otherwise  set  in an EXPORT {} or CLIENT {} block and are
       applied when export permissions are evaluated when a new file handle is encountered.

       The FSAL { Name } may not be changed and FSALs offer  limited  support  for  changing  any
       options  in  the  FSAL  block. Some FSALs may validate and warn if any options in the FSAL
       block are changed when such a change is not supported.

SEE ALSO

       ganesha-config(8)  ganesha-rgw-config(8)  ganesha-vfs-config(8)   ganesha-lustre-config(8)
       ganesha-xfs-config(8)  ganesha-gpfs-config(8) ganesha-9p-config(8) ganesha-proxy-config(8)
       ganesha-ceph-config(8)

                                           Sep 13, 2022                  GANESHA-EXPORT-CONFIG(8)