exportfs: add fid type

This patchset is a medium scale rewrite of the export operations interface.
The goal is to make the interface less complex, and easier to understand from
the filesystem side, aswell as preparing generic support for exporting of
64bit inode numbers.

This touches all nfs exporting filesystems, and I've done testing on all of
the filesystems I have here locally (xfs, ext2, ext3, reiserfs, jfs)

This patch:

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 <hch@lst.de>
Cc: Neil Brown <neilb@suse.de>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: <linux-ext4@vger.kernel.org>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Anton Altaparmakov <aia21@cantab.net>
Cc: David Chinner <dgc@sgi.com>
Cc: Timothy Shimmin <tes@sgi.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Chris Mason <mason@suse.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: "Vladimir V. Saveliev" <vs@namesys.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 31 insertions, 36 deletions

diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
index 7011d62acfc8..4f712e970584 100644
--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c
@@ -115,8 +115,7 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
         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 svc_fh *fhp, int type, int access)
 
                 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 svc_fh *fhp, int type, int access)
                                 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 svc_fh *fhp, int type, int access)
                         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 svc_export *exp, struct dentry *dentry,
                 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;
         }