X-Git-Url: https://git.decadent.org.uk/gitweb/?p=nfs-utils.git;a=blobdiff_plain;f=utils%2Fexportfs%2Fexports.man;h=4cddc793d24b69c1eab0781cd01e58d327119e24;hp=97264cdc6511880f69ed3d00a0c092043b1abffd;hb=4bcb2c85022812c36e6008d5d51466b4b0e61d86;hpb=de8fd61f8e692d5d8207d7c30e8914da05ca122f diff --git a/utils/exportfs/exports.man b/utils/exportfs/exports.man index 97264cd..4cddc79 100644 --- a/utils/exportfs/exports.man +++ b/utils/exportfs/exports.man @@ -1,5 +1,4 @@ -.TH EXPORTS 5 "28 October 1999" -.UC 5 +.TH EXPORTS 5 "4 March 2005" "Linux" "Linux File Formats Manual" .SH NAME exports \- NFS file systems being exported (for Kernel based NFS) .SH SYNOPSIS @@ -30,6 +29,9 @@ double quotes. You can also specify spaces or other unusual character in the export name using a backslash followed by the character code as three octal digits. .PP +To apply changes to this file, run exportfs -ra or /etc/init.d/nfs-kernel-server +reload (the latter being a distribution-specific extension). +.PP .SS Machine Name Formats NFS clients may be specified in a number of ways: .IP "single host @@ -45,9 +47,10 @@ parts or those containing a single dash (\-) are ignored. .IP "wildcards Machine names may contain the wildcard characters \fI*\fR and \fI?\fR. This can be used to make the \fIexports\fR file more compact; for instance, -\fI*.cs.foo.edu\fR matches all hosts in the domain \fIcs.foo.edu\fR. However, -these wildcard characters do not match the dots in a domain name, so the -above pattern does not include hosts such as \fIa.b.cs.foo.edu\fR. +\fI*.cs.foo.edu\fR matches all hosts in the domain +\fIcs.foo.edu\fR. As these characters also match the dots in a domain +name, the given pattern will also match all hosts within any subdomain +of \fIcs.foo.edu\fR. .IP "IP networks You can also export directories to all hosts on an IP (sub-) network simultaneously. This is done by specifying an IP address and netmask pair @@ -78,6 +81,11 @@ may work by accident when reverse DNS lookups fail. '''.B \-\-public\-root '''option. Multiple specifications of a public root will be ignored. .PP +.SS RPCSEC_GSS security +To restrict access to an export using rpcsec_gss security, use the special +string "gss/krb5" as the client. It is not possible to simultaneously require +rpcsec_gss and to make requirements on the IP address of the client. +.PP .SS General Options .IR exportfs understands the following export options: @@ -104,6 +112,13 @@ Using this option usually improves performance, but at the cost that an unclean server restart (i.e. a crash) can cause data to be lost or corrupted. +.TP +.IR sync +Reply to requests only after the changes have been committed to stable +storage (see +.IR async +above). + In releases of nfs-utils upto and including 1.0.0, this option was the default. In this and future releases, .I sync @@ -163,9 +178,17 @@ copes with the situation effectively. The option can be explicitly disabled with .IR hide . .TP +.IR crossmnt +This option is similar to +.I nohide +but it makes it possible for clients to move from the filesystem marked +with crossmnt to exported filesystems mounted on it. Thus when a child +filesystem "B" is mounted on a parent "A", setting crossmnt on "A" has +the same effect as setting "nohide" on B. +.TP .IR no_subtree_check This option disables subtree checking, which has mild security -implications, but can improve reliability is some circumstances. +implications, but can improve reliability in some circumstances. If a subdirectory of a filesystem is exported, but the whole filesystem isn't then whenever a NFS request arrives, the server must @@ -184,7 +207,7 @@ subtree checking is also used to make sure that files inside directories to which only root has access can only be accessed if the filesystem is exported with .I no_root_squash -(see below), even the file itself allows more general access. +(see below), even if the file itself allows more general access. As a general guide, a home directory filesystem, which is normally exported at the root and may see lots of file renames, should be @@ -217,6 +240,21 @@ be explicitly requested with either of the synonymous .IR auth_nlm , or .IR secure_locks . +.TP +.IR no_acl +On some specially patched kernels, and when exporting filesystems that +support ACLs, this option tells nfsd not to reveal ACLs to clients, so +they will see only a subset of actual permissions on the given file +system. This option is safe for filesystems used by NFSv2 clients and +old NFSv3 clients that perform access decisions locally. Current +NFSv3 clients use the ACCESS RPC to perform all access decisions on +the server. Note that the +.I no_acl +option only has effect on kernels specially patched to support it, and +when exporting filesystems with ACL support. The default is to export +with ACL support (i.e. by default, +.I no_acl +is off). '''.TP '''.I noaccess @@ -236,6 +274,47 @@ or '''.TP '''.IR link_absolute '''Leave all symbolic link as they are. This is the default operation. + +.TP +.IR mountpoint= path +.TP +.I mp +This option makes it possible to only export a directory if it has +successfully been mounted. +If no path is given (e.g. +.IR mountpoint " or " mp ) +then the export point must also be a mount point. If it isn't then +the export point is not exported. This allows you to be sure that the +directory underneath a mountpoint will never be exported by accident +if, for example, the filesystem failed to mount due to a disc error. + +If a path is given (e.g. +.IR mountpoint= "/path or " mp= /path) +then the nominted path must be a mountpoint for the exportpoint to be +exported. + +.TP +.IR fsid= num +This option forces the filesystem identification portion of the file +handle and file attributes used on the wire to be +.I num +instead of a number derived from the major and minor number of the +block device on which the filesystem is mounted. Any 32 bit number +can be used, but it must be unique amongst all the exported filesystems. + +This can be useful for NFS failover, to ensure that both servers of +the failover pair use the same NFS file handles for the shared filesystem +thus avoiding stale file handles after failover. + +Some Linux filesystems are not mounted on a block device; exporting +these via NFS requires the use of the +.I fsid +option (although that may still not be enough). + +The value 0 has a special meaning when use with NFSv4. NFSv4 has a +concept of a root of the overall exported filesystem. The export point +exported with fsid=0 will be used as this root. + .SS User ID Mapping .PP .I nfsd @@ -262,7 +341,7 @@ By default, '''in the password file at startup time. If it isn't found, a uid and gid .I exportfs chooses a uid and gid -of -2 (i.e. 65534) for squashed access. These values can also be overridden by +of 65534 for squashed access. These values can also be overridden by the .IR anonuid " and " anongid options. @@ -316,8 +395,11 @@ Here's the complete list of mapping options: .TP .IR root_squash Map requests from uid/gid 0 to the anonymous uid/gid. Note that this does -not apply to any other uids that might be equally sensitive, such as user -.IR bin . +not apply to any other uids or gids that might be equally sensitive, such as +user +.IR bin +or group +.IR staff . .TP .IR no_root_squash Turn off root squashing. This option is mainly useful for diskless clients. @@ -440,6 +522,12 @@ don't use a reserved port for NFS. '''entry. .SH FILES /etc/exports +.SH SEE ALSO +.BR exportfs (8), +.BR netgroup (5), +.BR mountd (8), +.BR nfsd (8), +.BR showmount (8). '''.SH DIAGNOSTICS '''An error parsing the file is reported using syslogd(8) as level NOTICE from '''a DAEMON whenever nfsd(8) or mountd(8) is started up. Any unknown