nfs: Support directory level exports

nfsx has followed traditional approach of exporting whole volumes
as NFS exports. The Platform requires and some users have approached us for
introducing exports of only specific directories instead of full Gluster
volumes. This commit introduces this support through two nfsx options:

Option 1:

=========
option nfs3.<volume-name>.export-dir <subdir1-in-vol>,<subdir2-in-vol>,..<subdirN-in-vol>

export-dir will allow the export of a particular dir as a single export
by itself. For eg.:

volume posix
        type storage/posix
        option directory /export/
end-volume

volume posix-ac
        type features/access-control
        subvolumes posix
end-volume

volume nfs
        type nfs/server
        subvolumes posix-ac
        option rpc-auth.addr.allow *
        option nfs3.posix-ac.export-dir /homes/shehjart
end-volume

A comma separate list of sub-directories will set up those dirs as separated exports.
At the nfs client, the mount command will be:

$ mount <nfsserver>:/posix-ac/homes/shehjart /mnt

Option 2:
=========
option nfs3.<volume-name>.export-volumes <on|off>

There can be situations where users only want the directory level
exports and require that volume exports be completely disabled. The
above option allows us to do this. By default, volume exports are
enabled. From the earlier example, replacing <volume-name> with
posix-ac, will disable mounting of the posix-ac volume as a whole.

Signed-off-by: Shehjar Tikoo <shehjart@gluster.com>
Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 989 (Support directory exports in nfsx)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=989

1 files changed, 35 insertions, 1 deletions

diff --git a/xlators/nfs/server/src/mount3.h b/xlators/nfs/server/src/mount3.h
index 7cfd2b0cb..f555bc7f1 100644
--- a/xlators/nfs/server/src/mount3.h
+++ b/xlators/nfs/server/src/mount3.h
@@ -33,6 +33,7 @@
 #include "list.h"
 #include "xdr-nfs3.h"
 #include "locking.h"
+#include "nfs3-fh.h"
 
 /* Registered with portmap */
 #define GF_MOUNTV3_PORT         38465
@@ -60,12 +61,28 @@ struct mountentry {
         char                    hostname[MNTPATHLEN];
 };
 
+#define MNT3_EXPTYPE_VOLUME     1
+#define MNT3_EXPTYPE_DIR        2
+
+struct mnt3_export {
+        struct list_head        explist;
+
+        /* The string that may contain either the volume name if the full volume
+         * is exported or the subdirectory in the volume.
+         */
+        char                    *expname;
+        xlator_t                *vol;
+        int                     exptype;
+};
+
 struct mount3_state {
         xlator_t                *nfsx;
 
         /* The buffers for all network IO are got from this pool. */
         struct iobuf_pool       *iobpool;
-        xlator_list_t           *exports;
+
+        /* List of exports, can be volumes or directories in those volumes. */
+        struct list_head        exportlist;
 
         /* List of current mount points over all the exports from this
          * server.
@@ -74,5 +91,22 @@ struct mount3_state {
 
         /* Used to protect the mountlist. */
         gf_lock_t               mountlock;
+
+        /* Set to 0 if exporting full volumes is disabled. On by default. */
+        int                     export_volumes;
 };
+
+
+struct mount3_resolve_state {
+        struct mnt3_export      *exp;
+        struct mount3_state     *mstate;
+        rpcsvc_request_t        *req;
+
+        char                    remainingdir[MNTPATHLEN];
+        loc_t                   resolveloc;
+        struct nfs3_fh          parentfh;
+};
+
+typedef struct mount3_resolve_state mnt3_resolve_t;
+
 #endif