[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, 69 insertions, 37 deletions

diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index 49c310b84923..bb3c314e2479 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -190,18 +190,17 @@ static int expkey_show(struct seq_file *m,
                        struct cache_head *h)
 {
         struct svc_expkey *ek ;
+        int i;
 
         if (h ==NULL) {
                 seq_puts(m, "#domain fsidtype fsid [path]\n");
                 return 0;
         }
         ek = container_of(h, struct svc_expkey, h);
-        seq_printf(m, "%s %d 0x%08x", ek->ek_client->name,
-                   ek->ek_fsidtype, ek->ek_fsid[0]);
-        if (ek->ek_fsidtype != 1)
-                seq_printf(m, "%08x", ek->ek_fsid[1]);
-        if (ek->ek_fsidtype == 2)
-                seq_printf(m, "%08x", ek->ek_fsid[2]);
+        seq_printf(m, "%s %d 0x", ek->ek_client->name,
+                   ek->ek_fsidtype);
+        for (i=0; i < key_len(ek->ek_fsidtype)/4; i++)
+                seq_printf(m, "%08x", ek->ek_fsid[i]);
         if (test_bit(CACHE_VALID, &h->flags) && 
             !test_bit(CACHE_NEGATIVE, &h->flags)) {
                 seq_printf(m, " ");
@@ -232,9 +231,8 @@ static inline void expkey_init(struct cache_head *cnew,
         kref_get(&item->ek_client->ref);
         new->ek_client = item->ek_client;
         new->ek_fsidtype = item->ek_fsidtype;
-        new->ek_fsid[0] = item->ek_fsid[0];
-        new->ek_fsid[1] = item->ek_fsid[1];
-        new->ek_fsid[2] = item->ek_fsid[2];
+
+        memcpy(new->ek_fsid, item->ek_fsid, sizeof(new->ek_fsid));
 }
 
 static inline void expkey_update(struct cache_head *cnew,
@@ -363,7 +361,7 @@ static struct svc_export *svc_export_update(struct svc_export *new,
                                             struct svc_export *old);
 static struct svc_export *svc_export_lookup(struct svc_export *);
 
-static int check_export(struct inode *inode, int flags)
+static int check_export(struct inode *inode, int flags, unsigned char *uuid)
 {
 
         /* We currently export only dirs and regular files.
@@ -376,12 +374,13 @@ static int check_export(struct inode *inode, int flags)
         /* There are two requirements on a filesystem to be exportable.
          * 1:  We must be able to identify the filesystem from a number.
          *       either a device number (so FS_REQUIRES_DEV needed)
-         *       or an FSID number (so NFSEXP_FSID needed).
+         *       or an FSID number (so NFSEXP_FSID or ->uuid is needed).
          * 2:  We must be able to find an inode from a filehandle.
          *       This means that s_export_op must be set.
          */
         if (!(inode->i_sb->s_type->fs_flags & FS_REQUIRES_DEV) &&
-            !(flags & NFSEXP_FSID)) {
+            !(flags & NFSEXP_FSID) &&
+            uuid == NULL) {
                 dprintk("exp_export: export of non-dev fs without fsid\n");
                 return -EINVAL;
         }
@@ -406,10 +405,6 @@ fsloc_parse(char **mesg, char *buf, struct nfsd4_fs_locations *fsloc)
         int len;
         int migrated, i, err;
 
-        len = qword_get(mesg, buf, PAGE_SIZE);
-        if (len != 5 || memcmp(buf, "fsloc", 5))
-                return 0;
-
         /* listsize */
         err = get_int(mesg, &fsloc->locations_count);
         if (err)
@@ -520,6 +515,8 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
         exp.ex_fslocs.locations_count = 0;
         exp.ex_fslocs.migrated = 0;
 
+        exp.ex_uuid = NULL;
+
         /* flags */
         err = get_int(&mesg, &an_int);
         if (err == -ENOENT)
@@ -543,12 +540,33 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
                 if (err) goto out;
                 exp.ex_fsid = an_int;
 
-                err = check_export(nd.dentry->d_inode, exp.ex_flags);
-                if (err) goto out;
+                while ((len = qword_get(&mesg, buf, PAGE_SIZE)) > 0) {
+                        if (strcmp(buf, "fsloc") == 0)
+                                err = fsloc_parse(&mesg, buf, &exp.ex_fslocs);
+                        else if (strcmp(buf, "uuid") == 0) {
+                                /* expect a 16 byte uuid encoded as \xXXXX... */
+                                len = qword_get(&mesg, buf, PAGE_SIZE);
+                                if (len != 16)
+                                        err  = -EINVAL;
+                                else {
+                                        exp.ex_uuid =
+                                                kmemdup(buf, 16, GFP_KERNEL);
+                                        if (exp.ex_uuid == NULL)
+                                                err = -ENOMEM;
+                                }
+                        } else
+                                /* quietly ignore unknown words and anything
+                                 * following. Newer user-space can try to set
+                                 * new values, then see what the result was.
+                                 */
+                                break;
+                        if (err)
+                                goto out;
+                }
 
-                err = fsloc_parse(&mesg, buf, &exp.ex_fslocs);
-                if (err)
-                        goto out;
+                err = check_export(nd.dentry->d_inode, exp.ex_flags,
+                                   exp.ex_uuid);
+                if (err) goto out;
         }
 
         expp = svc_export_lookup(&exp);
@@ -562,6 +580,8 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
         else
                 exp_put(expp);
  out:
+        nfsd4_fslocs_free(&exp.ex_fslocs);
+        kfree(exp.ex_uuid);
         kfree(exp.ex_path);
         if (nd.dentry)
                 path_release(&nd);
@@ -591,9 +611,19 @@ static int svc_export_show(struct seq_file *m,
         seq_escape(m, exp->ex_client->name, " \t\n\\");
         seq_putc(m, '(');
         if (test_bit(CACHE_VALID, &h->flags) && 
-            !test_bit(CACHE_NEGATIVE, &h->flags))
+            !test_bit(CACHE_NEGATIVE, &h->flags)) {
                 exp_flags(m, exp->ex_flags, exp->ex_fsid,
                           exp->ex_anon_uid, exp->ex_anon_gid, &exp->ex_fslocs);
+                if (exp->ex_uuid) {
+                        int i;
+                        seq_puts(m, ",uuid=");
+                        for (i=0; i<16; i++) {
+                                if ((i&3) == 0 && i)
+                                        seq_putc(m, ':');
+                                seq_printf(m, "%02x", exp->ex_uuid[i]);
+                        }
+                }
+        }
         seq_puts(m, ")\n");
         return 0;
 }
@@ -630,6 +660,8 @@ static void export_update(struct cache_head *cnew, struct cache_head *citem)
         new->ex_anon_uid = item->ex_anon_uid;
         new->ex_anon_gid = item->ex_anon_gid;
         new->ex_fsid = item->ex_fsid;
+        new->ex_uuid = item->ex_uuid;
+        item->ex_uuid = NULL;
         new->ex_path = item->ex_path;
         item->ex_path = NULL;
         new->ex_fslocs.locations = item->ex_fslocs.locations;
@@ -752,11 +784,11 @@ exp_get_key(svc_client *clp, dev_t dev, ino_t ino)
         u32 fsidv[3];
         
         if (old_valid_dev(dev)) {
-                mk_fsid_v0(fsidv, dev, ino);
-                return exp_find_key(clp, 0, fsidv, NULL);
+                mk_fsid(FSID_DEV, fsidv, dev, ino, 0, NULL);
+                return exp_find_key(clp, FSID_DEV, fsidv, NULL);
         }
-        mk_fsid_v3(fsidv, dev, ino);
-        return exp_find_key(clp, 3, fsidv, NULL);
+        mk_fsid(FSID_ENCODE_DEV, fsidv, dev, ino, 0, NULL);
+        return exp_find_key(clp, FSID_ENCODE_DEV, fsidv, NULL);
 }
 
 /*
@@ -767,9 +799,9 @@ exp_get_fsid_key(svc_client *clp, int fsid)
 {
         u32 fsidv[2];
 
-        mk_fsid_v1(fsidv, fsid);
+        mk_fsid(FSID_NUM, fsidv, 0, 0, fsid, NULL);
 
-        return exp_find_key(clp, 1, fsidv, NULL);
+        return exp_find_key(clp, FSID_NUM, fsidv, NULL);
 }
 
 svc_export *
@@ -883,8 +915,8 @@ static int exp_fsid_hash(svc_client *clp, struct svc_export *exp)
         if ((exp->ex_flags & NFSEXP_FSID) == 0)
                 return 0;
 
-        mk_fsid_v1(fsid, exp->ex_fsid);
-        return exp_set_key(clp, 1, fsid, exp);
+        mk_fsid(FSID_NUM, fsid, 0, 0, exp->ex_fsid, NULL);
+        return exp_set_key(clp, FSID_NUM, fsid, exp);
 }
 
 static int exp_hash(struct auth_domain *clp, struct svc_export *exp)
@@ -894,11 +926,11 @@ static int exp_hash(struct auth_domain *clp, struct svc_export *exp)
         dev_t dev = inode->i_sb->s_dev;
 
         if (old_valid_dev(dev)) {
-                mk_fsid_v0(fsid, dev, inode->i_ino);
-                return exp_set_key(clp, 0, fsid, exp);
+                mk_fsid(FSID_DEV, fsid, dev, inode->i_ino, 0, NULL);
+                return exp_set_key(clp, FSID_DEV, fsid, exp);
         }
-        mk_fsid_v3(fsid, dev, inode->i_ino);
-        return exp_set_key(clp, 3, fsid, exp);
+        mk_fsid(FSID_ENCODE_DEV, fsid, dev, inode->i_ino, 0, NULL);
+        return exp_set_key(clp, FSID_ENCODE_DEV, fsid, exp);
 }
 
 static void exp_unhash(struct svc_export *exp)
@@ -977,7 +1009,7 @@ exp_export(struct nfsctl_export *nxp)
                 goto finish;
         }
 
-        err = check_export(nd.dentry->d_inode, nxp->ex_flags);
+        err = check_export(nd.dentry->d_inode, nxp->ex_flags, NULL);
         if (err) goto finish;
 
         err = -ENOMEM;
@@ -1170,9 +1202,9 @@ exp_pseudoroot(struct auth_domain *clp, struct svc_fh *fhp,
         __be32 rv;
         u32 fsidv[2];
 
-        mk_fsid_v1(fsidv, 0);
+        mk_fsid(FSID_NUM, fsidv, 0, 0, 0, NULL);
 
-        exp = exp_find(clp, 1, fsidv, creq);
+        exp = exp_find(clp, FSID_NUM, fsidv, creq);
         if (IS_ERR(exp))
                 return nfserrno(PTR_ERR(exp));
         if (exp == NULL)