[PATCH] knfsd: add some new fsid types

Add support for using a filesystem UUID to identify and export point in the
filehandle.

For NFSv2, this UUID is xor-ed down to 4 or 8 bytes so that it doesn't take up
too much room.  For NFSv3+, we use the full 16 bytes, and possibly also a
64bit inode number for exports beneath the root of a filesystem.

When generating an fsid to return in 'stat' information, use the UUID (hashed
down to size) if it is available and a small 'fsid' was not specifically
provided.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 76 insertions, 23 deletions

diff --git a/include/linux/nfsd/nfsfh.h b/include/linux/nfsd/nfsfh.h
index d9c6c382165..11e568ee0ee 100644
--- a/include/linux/nfsd/nfsfh.h
+++ b/include/linux/nfsd/nfsfh.h
@@ -165,38 +165,91 @@ typedef struct svc_fh {
 
 } svc_fh;
 
-static inline void mk_fsid_v0(u32 *fsidv, dev_t dev, ino_t ino)
-{
-        fsidv[0] = htonl((MAJOR(dev)<<16) |
-                        MINOR(dev));
-        fsidv[1] = ino_t_to_u32(ino);
-}
+enum nfsd_fsid {
+        FSID_DEV = 0,
+        FSID_NUM,
+        FSID_MAJOR_MINOR,
+        FSID_ENCODE_DEV,
+        FSID_UUID4_INUM,
+        FSID_UUID8,
+        FSID_UUID16,
+        FSID_UUID16_INUM,
+};
 
-static inline void mk_fsid_v1(u32 *fsidv, u32 fsid)
-{
-        fsidv[0] = fsid;
-}
+enum fsid_source {
+        FSIDSOURCE_DEV,
+        FSIDSOURCE_FSID,
+        FSIDSOURCE_UUID,
+};
+extern enum fsid_source fsid_source(struct svc_fh *fhp);
 
-static inline void mk_fsid_v2(u32 *fsidv, dev_t dev, ino_t ino)
-{
-        fsidv[0] = htonl(MAJOR(dev));
-        fsidv[1] = htonl(MINOR(dev));
-        fsidv[2] = ino_t_to_u32(ino);
-}
 
-static inline void mk_fsid_v3(u32 *fsidv, dev_t dev, ino_t ino)
+/* This might look a little large to "inline" but in all calls except
+ * one, 'vers' is constant so moste of the function disappears.
+ */
+static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
+                           u32 fsid, unsigned char *uuid)
 {
-        fsidv[0] = new_encode_dev(dev);
-        fsidv[1] = ino_t_to_u32(ino);
+        u32 *up;
+        switch(vers) {
+        case FSID_DEV:
+                fsidv[0] = htonl((MAJOR(dev)<<16) |
+                                 MINOR(dev));
+                fsidv[1] = ino_t_to_u32(ino);
+                break;
+        case FSID_NUM:
+                fsidv[0] = fsid;
+                break;
+        case FSID_MAJOR_MINOR:
+                fsidv[0] = htonl(MAJOR(dev));
+                fsidv[1] = htonl(MINOR(dev));
+                fsidv[2] = ino_t_to_u32(ino);
+                break;
+
+        case FSID_ENCODE_DEV:
+                fsidv[0] = new_encode_dev(dev);
+                fsidv[1] = ino_t_to_u32(ino);
+                break;
+
+        case FSID_UUID4_INUM:
+                /* 4 byte fsid and inode number */
+                up = (u32*)uuid;
+                fsidv[0] = ino_t_to_u32(ino);
+                fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
+                break;
+
+        case FSID_UUID8:
+                /* 8 byte fsid  */
+                up = (u32*)uuid;
+                fsidv[0] = up[0] ^ up[2];
+                fsidv[1] = up[1] ^ up[3];
+                break;
+
+        case FSID_UUID16:
+                /* 16 byte fsid - NFSv3+ only */
+                memcpy(fsidv, uuid, 16);
+                break;
+
+        case FSID_UUID16_INUM:
+                /* 8 byte inode and 16 byte fsid */
+                *(u64*)fsidv = (u64)ino;
+                memcpy(fsidv+2, uuid, 16);
+                break;
+        default: BUG();
+        }
 }
 
 static inline int key_len(int type)
 {
         switch(type) {
-        case 0: return 8;
-        case 1: return 4;
-        case 2: return 12;
-        case 3: return 8;
+        case FSID_DEV:          return 8;
+        case FSID_NUM:          return 4;
+        case FSID_MAJOR_MINOR:  return 12;
+        case FSID_ENCODE_DEV:   return 8;
+        case FSID_UUID4_INUM:   return 8;
+        case FSID_UUID8:        return 8;
+        case FSID_UUID16:       return 16;
+        case FSID_UUID16_INUM:  return 24;
         default: return 0;
         }
 }