Add a structured fid type so that we don't have to pass an array
of u32 values around everywhere.  It's a union of possible layouts.

As a start there's only the u32 array and the traditional 32bit
inode format, but there will be more in one of my next patchset
when I start to document the various filehandle formats we have
in lowlevel filesystems better.

Also add an enum that gives the various filehandle types human-
readable names.

Note:  Some people might think the struct containing an anonymous
union is ugly, but I didn't want to pass around a raw union type.


Signed-off-by: Christoph Hellwig <[EMAIL PROTECTED]>

Index: linux-2.6/include/linux/exportfs.h
===================================================================
--- linux-2.6.orig/include/linux/exportfs.h     2007-09-13 15:10:59.000000000 
+0200
+++ linux-2.6/include/linux/exportfs.h  2007-09-13 15:11:11.000000000 +0200
@@ -7,6 +7,44 @@ struct dentry;
 struct super_block;
 struct vfsmount;
 
+/*
+ * The fileid_type identifies how the file within the filesystem is encoded.
+ * In theory this is freely set and parsed by the filesystem, but we try to
+ * stick to conventions so we can share some generic code and don't confuse
+ * sniffers like ethereal/wireshark.
+ *
+ * The filesystem must not use the value '0' or '0xff'.
+ */
+enum fid_type {
+       /*
+        * The root, or export point, of the filesystem.
+        * (Never actually passed down to the filesystem.
+        */
+       FILEID_ROOT = 0,
+
+       /*
+        * 32bit inode number, 32 bit generation number.
+        */
+       FILEID_INO32_GEN = 1,
+
+       /*
+        * 32bit inode number, 32 bit generation number,
+        * 32 bit parent directory inode number.
+        */
+       FILEID_INO32_GEN_PARENT = 2,
+};
+
+struct fid {
+       union {
+               struct {
+                       u32 ino;
+                       u32 gen;
+                       u32 parent_ino;
+                       u32 parent_gen;
+               } i32;
+               __u32 raw[6];
+       };
+};
 
 /**
  * struct export_operations - for nfsd to communicate with file systems
@@ -117,9 +155,9 @@ extern struct dentry *find_exported_dent
        void *parent, int (*acceptable)(void *context, struct dentry *de),
        void *context);
 
-extern int exportfs_encode_fh(struct dentry *dentry, __u32 *fh, int *max_len,
-       int connectable);
-extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, __u32 *fh,
+extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,
+       int *max_len, int connectable);
+extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
        int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *),
        void *context);
 
Index: linux-2.6/fs/nfsd/nfsfh.c
===================================================================
--- linux-2.6.orig/fs/nfsd/nfsfh.c      2007-09-13 15:10:59.000000000 +0200
+++ linux-2.6/fs/nfsd/nfsfh.c   2007-09-13 15:13:32.000000000 +0200
@@ -115,8 +115,7 @@ fh_verify(struct svc_rqst *rqstp, struct
        dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
 
        if (!fhp->fh_dentry) {
-               __u32 *datap=NULL;
-               __u32 tfh[3];           /* filehandle fragment for oldstyle 
filehandles */
+               struct fid *fid = NULL, sfid;
                int fileid_type;
                int data_left = fh->fh_size/4;
 
@@ -128,7 +127,6 @@ fh_verify(struct svc_rqst *rqstp, struct
 
                if (fh->fh_version == 1) {
                        int len;
-                       datap = fh->fh_auth;
                        if (--data_left<0) goto out;
                        switch (fh->fh_auth_type) {
                        case 0: break;
@@ -144,9 +142,11 @@ fh_verify(struct svc_rqst *rqstp, struct
                                fh->fh_fsid[1] = fh->fh_fsid[2];
                        }
                        if ((data_left -= len)<0) goto out;
-                       exp = rqst_exp_find(rqstp, fh->fh_fsid_type, datap);
-                       datap += len;
+                       exp = rqst_exp_find(rqstp, fh->fh_fsid_type,
+                                           fh->fh_auth);
+                       fid = (struct fid *)(fh->fh_auth + len);
                } else {
+                       __u32 tfh[2];
                        dev_t xdev;
                        ino_t xino;
                        if (fh->fh_size != NFS_FHSIZE)
@@ -190,22 +190,22 @@ fh_verify(struct svc_rqst *rqstp, struct
                        error = nfserr_badhandle;
 
                if (fh->fh_version != 1) {
-                       tfh[0] = fh->ofh_ino;
-                       tfh[1] = fh->ofh_generation;
-                       tfh[2] = fh->ofh_dirino;
-                       datap = tfh;
+                       sfid.i32.ino = fh->ofh_ino;
+                       sfid.i32.gen = fh->ofh_generation;
+                       sfid.i32.parent_ino = fh->ofh_dirino;
+                       fid = &sfid;
                        data_left = 3;
                        if (fh->ofh_dirino == 0)
-                               fileid_type = 1;
+                               fileid_type = FILEID_INO32_GEN;
                        else
-                               fileid_type = 2;
+                               fileid_type = FILEID_INO32_GEN_PARENT;
                } else
                        fileid_type = fh->fh_fileid_type;
 
-               if (fileid_type == 0)
+               if (fileid_type == FILEID_ROOT)
                        dentry = dget(exp->ex_dentry);
                else {
-                       dentry = exportfs_decode_fh(exp->ex_mnt, datap,
+                       dentry = exportfs_decode_fh(exp->ex_mnt, fid,
                                        data_left, fileid_type,
                                        nfsd_acceptable, exp);
                }
@@ -286,16 +286,21 @@ out:
  * an inode.  In this case a call to fh_update should be made
  * before the fh goes out on the wire ...
  */
-static inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
-                            __u32 *datap, int *maxsize)
+static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
+               struct dentry *dentry)
 {
-       if (dentry == exp->ex_dentry) {
-               *maxsize = 0;
-               return 0;
-       }
+       if (dentry != exp->ex_dentry) {
+               struct fid *fid = (struct fid *)
+                       (fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1);
+               int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
+               int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
 
-       return exportfs_encode_fh(dentry, datap, maxsize,
-                         !(exp->ex_flags & NFSEXP_NOSUBTREECHECK));
+               fhp->fh_handle.fh_fileid_type =
+                       exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
+               fhp->fh_handle.fh_size += maxsize * 4;
+       } else {
+               fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
+       }
 }
 
 /*
@@ -457,12 +462,8 @@ fh_compose(struct svc_fh *fhp, struct sv
                datap += len/4;
                fhp->fh_handle.fh_size = 4 + len;
 
-               if (inode) {
-                       int size = (fhp->fh_maxsize-len-4)/4;
-                       fhp->fh_handle.fh_fileid_type =
-                               _fh_update(dentry, exp, datap, &size);
-                       fhp->fh_handle.fh_size += size*4;
-               }
+               if (inode)
+                       _fh_update(fhp, exp, dentry);
                if (fhp->fh_handle.fh_fileid_type == 255)
                        return nfserr_opnotsupp;
        }
@@ -479,7 +480,6 @@ __be32
 fh_update(struct svc_fh *fhp)
 {
        struct dentry *dentry;
-       __u32 *datap;
 
        if (!fhp->fh_dentry)
                goto out_bad;
@@ -490,15 +490,10 @@ fh_update(struct svc_fh *fhp)
        if (fhp->fh_handle.fh_version != 1) {
                _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
        } else {
-               int size;
-               if (fhp->fh_handle.fh_fileid_type != 0)
+               if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
                        goto out;
-               datap = fhp->fh_handle.fh_auth+
-                       fhp->fh_handle.fh_size/4 -1;
-               size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
-               fhp->fh_handle.fh_fileid_type =
-                       _fh_update(dentry, fhp->fh_export, datap, &size);
-               fhp->fh_handle.fh_size += size*4;
+
+               _fh_update(fhp, fhp->fh_export, dentry);
                if (fhp->fh_handle.fh_fileid_type == 255)
                        return nfserr_opnotsupp;
        }
Index: linux-2.6/fs/exportfs/expfs.c
===================================================================
--- linux-2.6.orig/fs/exportfs/expfs.c  2007-09-13 15:10:59.000000000 +0200
+++ linux-2.6/fs/exportfs/expfs.c       2007-09-13 15:13:02.000000000 +0200
@@ -434,29 +434,29 @@ out:
  * can be used to check that it is still valid.  It places them in the
  * filehandle fragment where export_decode_fh expects to find them.
  */
-static int export_encode_fh(struct dentry *dentry, __u32 *fh, int *max_len,
-                  int connectable)
+static int export_encode_fh(struct dentry *dentry, struct fid *fid,
+               int *max_len, int connectable)
 {
        struct inode * inode = dentry->d_inode;
        int len = *max_len;
-       int type = 1;
+       int type = FILEID_INO32_GEN;
        
        if (len < 2 || (connectable && len < 4))
                return 255;
 
        len = 2;
-       fh[0] = inode->i_ino;
-       fh[1] = inode->i_generation;
+       fid->i32.ino = inode->i_ino;
+       fid->i32.gen = inode->i_generation;
        if (connectable && !S_ISDIR(inode->i_mode)) {
                struct inode *parent;
 
                spin_lock(&dentry->d_lock);
                parent = dentry->d_parent->d_inode;
-               fh[2] = parent->i_ino;
-               fh[3] = parent->i_generation;
+               fid->i32.parent_ino = parent->i_ino;
+               fid->i32.parent_gen = parent->i_generation;
                spin_unlock(&dentry->d_lock);
                len = 4;
-               type = 2;
+               type = FILEID_INO32_GEN_PARENT;
        }
        *max_len = len;
        return type;
@@ -494,34 +494,34 @@ static struct dentry *export_decode_fh(s
                                   acceptable, context);
 }
 
-int exportfs_encode_fh(struct dentry *dentry, __u32 *fh, int *max_len,
+int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, int *max_len,
                int connectable)
 {
        struct export_operations *nop = dentry->d_sb->s_export_op;
        int error;
 
        if (nop->encode_fh)
-               error = nop->encode_fh(dentry, fh, max_len, connectable);
+               error = nop->encode_fh(dentry, fid->raw, max_len, connectable);
        else
-               error = export_encode_fh(dentry, fh, max_len, connectable);
+               error = export_encode_fh(dentry, fid, max_len, connectable);
 
        return error;
 }
 EXPORT_SYMBOL_GPL(exportfs_encode_fh);
 
-struct dentry *exportfs_decode_fh(struct vfsmount *mnt, __u32 *fh, int fh_len,
-               int fileid_type, int (*acceptable)(void *, struct dentry *),
-               void *context)
+struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
+               int fh_len, int fileid_type,
+               int (*acceptable)(void *, struct dentry *), void *context)
 {
        struct export_operations *nop = mnt->mnt_sb->s_export_op;
        struct dentry *result;
 
        if (nop->decode_fh) {
-               result = nop->decode_fh(mnt->mnt_sb, fh, fh_len, fileid_type,
-                       acceptable, context);
+               result = nop->decode_fh(mnt->mnt_sb, fid->raw, fh_len,
+                                       fileid_type, acceptable, context);
        } else {
-               result = export_decode_fh(mnt->mnt_sb, fh, fh_len, fileid_type,
-                       acceptable, context);
+               result = export_decode_fh(mnt->mnt_sb, fid->raw, fh_len,
+                                         fileid_type, acceptable, context);
        }
 
        return result;

--
-
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