4 * (C) 2004 Paul Serice - The new inode scheme requires switching
5 * from iget() to iget5_locked() which means
6 * the NFS export operations have to be hand
7 * coded because the default routines rely on
10 * The following files are helpful:
12 * Documentation/filesystems/nfs/Exporting
13 * fs/exportfs/expfs.c.
18 static struct dentry
*
19 isofs_export_iget(struct super_block
*sb
,
27 return ERR_PTR(-ESTALE
);
28 inode
= isofs_iget(sb
, block
, offset
);
30 return ERR_CAST(inode
);
31 if (generation
&& inode
->i_generation
!= generation
) {
33 return ERR_PTR(-ESTALE
);
35 return d_obtain_alias(inode
);
38 /* This function is surprisingly simple. The trick is understanding
39 * that "child" is always a directory. So, to find its parent, you
40 * simply need to find its ".." entry, normalize its block and offset,
41 * and return the underlying inode. See the comments for
42 * isofs_normalize_block_and_offset(). */
43 static struct dentry
*isofs_export_get_parent(struct dentry
*child
)
45 unsigned long parent_block
= 0;
46 unsigned long parent_offset
= 0;
47 struct inode
*child_inode
= child
->d_inode
;
48 struct iso_inode_info
*e_child_inode
= ISOFS_I(child_inode
);
49 struct iso_directory_record
*de
= NULL
;
50 struct buffer_head
* bh
= NULL
;
51 struct dentry
*rv
= NULL
;
53 /* "child" must always be a directory. */
54 if (!S_ISDIR(child_inode
->i_mode
)) {
55 printk(KERN_ERR
"isofs: isofs_export_get_parent(): "
56 "child is not a directory!\n");
57 rv
= ERR_PTR(-EACCES
);
61 /* It is an invariant that the directory offset is zero. If
62 * it is not zero, it means the directory failed to be
63 * normalized for some reason. */
64 if (e_child_inode
->i_iget5_offset
!= 0) {
65 printk(KERN_ERR
"isofs: isofs_export_get_parent(): "
66 "child directory not normalized!\n");
67 rv
= ERR_PTR(-EACCES
);
71 /* The child inode has been normalized such that its
72 * i_iget5_block value points to the "." entry. Fortunately,
73 * the ".." entry is located in the same block. */
74 parent_block
= e_child_inode
->i_iget5_block
;
76 /* Get the block in question. */
77 bh
= sb_bread(child_inode
->i_sb
, parent_block
);
79 rv
= ERR_PTR(-EACCES
);
83 /* This is the "." entry. */
84 de
= (struct iso_directory_record
*)bh
->b_data
;
86 /* The ".." entry is always the second entry. */
87 parent_offset
= (unsigned long)isonum_711(de
->length
);
88 de
= (struct iso_directory_record
*)(bh
->b_data
+ parent_offset
);
90 /* Verify it is in fact the ".." entry. */
91 if ((isonum_711(de
->name_len
) != 1) || (de
->name
[0] != 1)) {
92 printk(KERN_ERR
"isofs: Unable to find the \"..\" "
93 "directory for NFS.\n");
94 rv
= ERR_PTR(-EACCES
);
99 isofs_normalize_block_and_offset(de
, &parent_block
, &parent_offset
);
101 rv
= d_obtain_alias(isofs_iget(child_inode
->i_sb
, parent_block
,
110 isofs_export_encode_fh(struct inode
*inode
,
113 struct inode
*parent
)
115 struct iso_inode_info
* ei
= ISOFS_I(inode
);
118 __u16
*fh16
= (__u16
*)fh32
;
121 * WARNING: max_len is 5 for NFSv2. Because of this
122 * limitation, we use the lower 16 bits of fh32[1] to hold the
123 * offset of the inode and the upper 16 bits of fh32[1] to
124 * hold the offset of the parent.
126 if (parent
&& (len
< 5)) {
129 } else if (len
< 3) {
135 fh32
[0] = ei
->i_iget5_block
;
136 fh16
[2] = (__u16
)ei
->i_iget5_offset
; /* fh16 [sic] */
137 fh32
[2] = inode
->i_generation
;
139 struct iso_inode_info
*eparent
;
140 eparent
= ISOFS_I(parent
);
141 fh32
[3] = eparent
->i_iget5_block
;
142 fh16
[3] = (__u16
)eparent
->i_iget5_offset
; /* fh16 [sic] */
143 fh32
[4] = parent
->i_generation
;
157 u32 parent_generation
;
160 static struct dentry
*isofs_fh_to_dentry(struct super_block
*sb
,
161 struct fid
*fid
, int fh_len
, int fh_type
)
163 struct isofs_fid
*ifid
= (struct isofs_fid
*)fid
;
165 if (fh_len
< 3 || fh_type
> 2)
168 return isofs_export_iget(sb
, ifid
->block
, ifid
->offset
,
172 static struct dentry
*isofs_fh_to_parent(struct super_block
*sb
,
173 struct fid
*fid
, int fh_len
, int fh_type
)
175 struct isofs_fid
*ifid
= (struct isofs_fid
*)fid
;
180 return isofs_export_iget(sb
,
181 fh_len
> 2 ? ifid
->parent_block
: 0,
183 fh_len
> 4 ? ifid
->parent_generation
: 0);
186 const struct export_operations isofs_export_ops
= {
187 .encode_fh
= isofs_export_encode_fh
,
188 .fh_to_dentry
= isofs_fh_to_dentry
,
189 .fh_to_parent
= isofs_fh_to_parent
,
190 .get_parent
= isofs_export_get_parent
,