[PATCH] - kNFSd in 2.5.15 - Require export operations for exporting a filesystem

This removes the old alternates to export_operations for exporting a
filesystem.

It removes fh_to_dentry, dentry_to_fh, and s_nfsd_free_path_sem.  It
also removes a lot of code.

The fs/ntfs change is because it was setting fh_to_dentry and
dentry_to_fh (which no longer exist) to NULL.

Documentation/filesystems/porting

@@ -146,3 +146,9 @@ support for this helper, particularly get_parent.
 
 It is planned that this will be required for exporting once the code
 settles down a bit.
+
+[mandatory]
+
+s_export_op is now required for exporting a filesystem.
+isofs, ext2, ext3, resierfs, fat
+can be used as examples of very different filesystems.

fs/nfsd/export.c

@@ -313,15 +313,12 @@ exp_export(struct nfsctl_export *nxp)
 	 *       either a device number (so FS_REQUIRES_DEV needed)
 	 *       or an FSID number (so NFSEXP_FSID needed).
 	 * 2:  We must be able to find an inode from a filehandle.
-	 *       either using fh_to_dentry (prefered)
-	 *       or using read_inode (the hack).
+	 *       This means that s_export_op must be set.
 	 */
 	if (((inode->i_sb->s_type->fs_flags & FS_REQUIRES_DEV)
-	      || (nxp->ex_flags & NFSEXP_FSID))
+	     || (nxp->ex_flags & NFSEXP_FSID))
 	    &&
-	    (inode->i_sb->s_op->read_inode
-	     || inode->i_sb->s_export_op
-	     || inode->i_sb->s_op->fh_to_dentry)) 
+	    inode->i_sb->s_export_op)
 		/* Ok, we can export it */;
 	else {
 		dprintk("exp_export: export of invalid fs type.\n");

fs/ntfs/super.c

@@ -1441,14 +1441,7 @@ struct super_operations ntfs_sops = {
 	clear_inode:	ntfs_clear_big_inode,	/* VFS: Called when an inode is
 						   removed from memory. */
 	umount_begin:	NULL,		/* Forced umount. */
-	/*
-	 * These are NFSd support functions but NTFS is a standard fs so
-	 * shouldn't need to implement these manually. At least we can try
-	 * without and if it doesn't work in some way we can always implement
-	 * something here.
-	 */
-	fh_to_dentry:	NULL,		/* Get dentry for given file handle. */
-	dentry_to_fh:	NULL,		/* Get file handle for given dentry. */
+
 	show_options:	ntfs_show_options, /* Show mount options in proc. */
 };
 

fs/super.c

@@ -58,7 +58,6 @@ static struct super_block *alloc_super(void)
 		s->s_count = S_BIAS;
 		atomic_set(&s->s_active, 1);
 		sema_init(&s->s_vfs_rename_sem,1);
-		sema_init(&s->s_nfsd_free_path_sem,1);
 		sema_init(&s->s_dquot.dqio_sem, 1);
 		sema_init(&s->s_dquot.dqoff_sem, 1);
 		s->s_maxbytes = MAX_NON_LFS;

include/linux/fs.h

@@ -660,15 +660,6 @@ struct super_block {
 	 * even looking at it. You had been warned.
 	 */
 	struct semaphore s_vfs_rename_sem;	/* Kludge */
-
-	/* The next field is used by knfsd when converting a (inode number based)
-	 * file handle into a dentry. As it builds a path in the dcache tree from
-	 * the bottom up, there may for a time be a subpath of dentrys which is not
-	 * connected to the main tree.  This semaphore ensure that there is only ever
-	 * one such free path per filesystem.  Note that unconnected files (or other
-	 * non-directories) are allowed, but not unconnected diretories.
-	 */
-	struct semaphore s_nfsd_free_path_sem;
 };
 
 /*
@@ -798,30 +789,6 @@ struct super_operations {
 	void (*clear_inode) (struct inode *);
 	void (*umount_begin) (struct super_block *);
 
-	/* Following are for knfsd to interact with "interesting" filesystems
-	 * Currently just reiserfs, but possibly FAT and others later
-	 *
-	 * fh_to_dentry is given a filehandle fragement with length, and a type flag
-	 *   and must return a dentry for the referenced object or, if "parent" is
-	 *   set, a dentry for the parent of the object.
-	 *   If a dentry cannot be found, a "root" dentry should be created and
-	 *   flaged as DCACHE_DISCONNECTED. nfsd_iget is an example implementation.
-	 *
-	 * dentry_to_fh is given a dentry and must generate the filesys specific
-	 *   part of the file handle.  Available length is passed in *lenp and used
-	 *   length should be returned therein.
-	 *   If need_parent is set, then dentry_to_fh should encode sufficient information
-	 *   to find the (current) parent.
-	 *   dentry_to_fh should return a 1byte "type" which will be passed back in
-	 *   the fhtype arguement to fh_to_dentry.  Type of 0 is reserved.
-	 *   If filesystem was exportable before the introduction of fh_to_dentry,
-	 *   types 1 and 2 should be used is that same way as the generic code.
-	 *   Type 255 means error.
-	 *
-	 * Lengths are in units of 4bytes, not bytes.
-	 */
-	struct dentry * (*fh_to_dentry)(struct super_block *sb, __u32 *fh, int len, int fhtype, int parent);
-	int (*dentry_to_fh)(struct dentry *, __u32 *fh, int *lenp, int need_parent);
 	int (*show_options)(struct seq_file *, struct vfsmount *);
 };