[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, 46 insertions, 42 deletions

diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
index 12c5e7421374..286bc4d356f4 100644
--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c
@@ -119,9 +119,6 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 
         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
 
-        /* keep this filehandle for possible reference  when encoding attributes */
-        rqstp->rq_reffh = fh;
-
         if (!fhp->fh_dentry) {
                 __u32 *datap=NULL;
                 __u32 tfh[3];           /* filehandle fragment for oldstyle filehandles */
@@ -146,10 +143,10 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
                         }
                         len = key_len(fh->fh_fsid_type) / 4;
                         if (len == 0) goto out;
-                        if  (fh->fh_fsid_type == 2) {
+                        if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
                                 /* deprecated, convert to type 3 */
-                                len = 3;
-                                fh->fh_fsid_type = 3;
+                                len = key_len(FSID_ENCODE_DEV)/4;
+                                fh->fh_fsid_type = FSID_ENCODE_DEV;
                                 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
                                 fh->fh_fsid[1] = fh->fh_fsid[2];
                         }
@@ -164,8 +161,9 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
                         /* assume old filehandle format */
                         xdev = old_decode_dev(fh->ofh_xdev);
                         xino = u32_to_ino_t(fh->ofh_xino);
-                        mk_fsid_v0(tfh, xdev, xino);
-                        exp = exp_find(rqstp->rq_client, 0, tfh, &rqstp->rq_chandle);
+                        mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
+                        exp = exp_find(rqstp->rq_client, FSID_DEV, tfh,
+                                       &rqstp->rq_chandle);
                 }
 
                 if (IS_ERR(exp) && (PTR_ERR(exp) == -EAGAIN
@@ -334,6 +332,7 @@ fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
         struct dentry *parent = dentry->d_parent;
         __u32 *datap;
         dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
+        int root_export = (exp->ex_dentry == exp->ex_dentry->d_sb->s_root);
 
         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
                 MAJOR(ex_dev), MINOR(ex_dev),
@@ -348,19 +347,31 @@ fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
         if (ref_fh && ref_fh->fh_export == exp) {
                 version = ref_fh->fh_handle.fh_version;
                 if (version == 0xca)
-                        fsid_type = 0;
+                        fsid_type = FSID_DEV;
                 else
                         fsid_type = ref_fh->fh_handle.fh_fsid_type;
                 /* We know this version/type works for this export
                  * so there is no need for further checks.
                  */
+        } else if (exp->ex_uuid) {
+                if (fhp->fh_maxsize >= 64) {
+                        if (root_export)
+                                fsid_type = FSID_UUID16;
+                        else
+                                fsid_type = FSID_UUID16_INUM;
+                } else {
+                        if (root_export)
+                                fsid_type = FSID_UUID8;
+                        else
+                                fsid_type = FSID_UUID4_INUM;
+                }
         } else if (exp->ex_flags & NFSEXP_FSID)
-                fsid_type = 1;
+                fsid_type = FSID_NUM;
         else if (!old_valid_dev(ex_dev))
                 /* for newer device numbers, we must use a newer fsid format */
-                fsid_type = 3;
+                fsid_type = FSID_ENCODE_DEV;
         else
-                fsid_type = 0;
+                fsid_type = FSID_DEV;
 
         if (ref_fh == fhp)
                 fh_put(ref_fh);
@@ -396,36 +407,10 @@ fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
                 fhp->fh_handle.fh_auth_type = 0;
                 datap = fhp->fh_handle.fh_auth+0;
                 fhp->fh_handle.fh_fsid_type = fsid_type;
-                switch (fsid_type) {
-                case 0:
-                        /*
-                         * fsid_type 0:
-                         * 2byte major, 2byte minor, 4byte inode
-                         */
-                        mk_fsid_v0(datap, ex_dev,
-                                   exp->ex_dentry->d_inode->i_ino);
-                        break;
-                case 1:
-                        /* fsid_type 1 == 4 bytes filesystem id */
-                        mk_fsid_v1(datap, exp->ex_fsid);
-                        break;
-                case 2:
-                        /*
-                         * fsid_type 2:
-                         * 4byte major, 4byte minor, 4byte inode
-                         */
-                        mk_fsid_v2(datap, ex_dev,
-                                   exp->ex_dentry->d_inode->i_ino);
-                        break;
-                case 3:
-                        /*
-                         * fsid_type 3:
-                         * 4byte devicenumber, 4byte inode
-                         */
-                        mk_fsid_v3(datap, ex_dev,
-                                   exp->ex_dentry->d_inode->i_ino);
-                        break;
-                }
+                mk_fsid(fsid_type, datap, ex_dev,
+                        exp->ex_dentry->d_inode->i_ino,
+                        exp->ex_fsid, exp->ex_uuid);
+
                 len = key_len(fsid_type);
                 datap += len/4;
                 fhp->fh_handle.fh_size = 4 + len;
@@ -530,3 +515,22 @@ char * SVCFH_fmt(struct svc_fh *fhp)
                 fh->fh_base.fh_pad[5]);
         return buf;
 }
+
+enum fsid_source fsid_source(struct svc_fh *fhp)
+{
+        if (fhp->fh_handle.fh_version != 1)
+                return FSIDSOURCE_DEV;
+        switch(fhp->fh_handle.fh_fsid_type) {
+        case FSID_DEV:
+        case FSID_ENCODE_DEV:
+        case FSID_MAJOR_MINOR:
+                return FSIDSOURCE_DEV;
+        case FSID_NUM:
+                return FSIDSOURCE_FSID;
+        default:
+                if (fhp->fh_export->ex_flags & NFSEXP_FSID)
+                        return FSIDSOURCE_FSID;
+                else
+                        return FSIDSOURCE_UUID;
+        }
+}