1 /*
2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
3 * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
4 *
5 * This copyrighted material is made available to anyone wishing to use,
6 * modify, copy, or redistribute it subject to the terms and conditions
7 * of the GNU General Public License version 2.
8 */
9
10 #include <linux/slab.h>
11 #include <linux/spinlock.h>
12 #include <linux/completion.h>
13 #include <linux/buffer_head.h>
14 #include <linux/exportfs.h>
15 #include <linux/gfs2_ondisk.h>
16 #include <linux/crc32.h>
17 #include <linux/lm_interface.h>
18
19 #include "gfs2.h"
20 #include "incore.h"
21 #include "dir.h"
22 #include "glock.h"
23 #include "glops.h"
24 #include "inode.h"
25 #include "super.h"
26 #include "rgrp.h"
27 #include "util.h"
28
29 #define GFS2_SMALL_FH_SIZE 4
30 #define GFS2_LARGE_FH_SIZE 8
31 #define GFS2_OLD_FH_SIZE 10
32
gfs2_encode_fh(struct dentry * dentry,__u32 * p,int * len,int connectable)33 static int gfs2_encode_fh(struct dentry *dentry, __u32 *p, int *len,
34 int connectable)
35 {
36 __be32 *fh = (__force __be32 *)p;
37 struct inode *inode = dentry->d_inode;
38 struct super_block *sb = inode->i_sb;
39 struct gfs2_inode *ip = GFS2_I(inode);
40
41 if (*len < GFS2_SMALL_FH_SIZE ||
42 (connectable && *len < GFS2_LARGE_FH_SIZE))
43 return 255;
44
45 fh[0] = cpu_to_be32(ip->i_no_formal_ino >> 32);
46 fh[1] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
47 fh[2] = cpu_to_be32(ip->i_no_addr >> 32);
48 fh[3] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
49 *len = GFS2_SMALL_FH_SIZE;
50
51 if (!connectable || inode == sb->s_root->d_inode)
52 return *len;
53
54 spin_lock(&dentry->d_lock);
55 inode = dentry->d_parent->d_inode;
56 ip = GFS2_I(inode);
57 igrab(inode);
58 spin_unlock(&dentry->d_lock);
59
60 fh[4] = cpu_to_be32(ip->i_no_formal_ino >> 32);
61 fh[5] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
62 fh[6] = cpu_to_be32(ip->i_no_addr >> 32);
63 fh[7] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
64 *len = GFS2_LARGE_FH_SIZE;
65
66 iput(inode);
67
68 return *len;
69 }
70
71 struct get_name_filldir {
72 struct gfs2_inum_host inum;
73 char *name;
74 };
75
get_name_filldir(void * opaque,const char * name,int length,loff_t offset,u64 inum,unsigned int type)76 static int get_name_filldir(void *opaque, const char *name, int length,
77 loff_t offset, u64 inum, unsigned int type)
78 {
79 struct get_name_filldir *gnfd = opaque;
80
81 if (inum != gnfd->inum.no_addr)
82 return 0;
83
84 memcpy(gnfd->name, name, length);
85 gnfd->name[length] = 0;
86
87 return 1;
88 }
89
gfs2_get_name(struct dentry * parent,char * name,struct dentry * child)90 static int gfs2_get_name(struct dentry *parent, char *name,
91 struct dentry *child)
92 {
93 struct inode *dir = parent->d_inode;
94 struct inode *inode = child->d_inode;
95 struct gfs2_inode *dip, *ip;
96 struct get_name_filldir gnfd;
97 struct gfs2_holder gh;
98 u64 offset = 0;
99 int error;
100
101 if (!dir)
102 return -EINVAL;
103
104 if (!S_ISDIR(dir->i_mode) || !inode)
105 return -EINVAL;
106
107 dip = GFS2_I(dir);
108 ip = GFS2_I(inode);
109
110 *name = 0;
111 gnfd.inum.no_addr = ip->i_no_addr;
112 gnfd.inum.no_formal_ino = ip->i_no_formal_ino;
113 gnfd.name = name;
114
115 error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
116 if (error)
117 return error;
118
119 error = gfs2_dir_read(dir, &offset, &gnfd, get_name_filldir);
120
121 gfs2_glock_dq_uninit(&gh);
122
123 if (!error && !*name)
124 error = -ENOENT;
125
126 return error;
127 }
128
gfs2_get_parent(struct dentry * child)129 static struct dentry *gfs2_get_parent(struct dentry *child)
130 {
131 struct qstr dotdot;
132 struct dentry *dentry;
133
134 /*
135 * XXX(hch): it would be a good idea to keep this around as a
136 * static variable.
137 */
138 gfs2_str2qstr(&dotdot, "..");
139
140 dentry = d_obtain_alias(gfs2_lookupi(child->d_inode, &dotdot, 1));
141 if (!IS_ERR(dentry))
142 dentry->d_op = &gfs2_dops;
143 return dentry;
144 }
145
gfs2_get_dentry(struct super_block * sb,struct gfs2_inum_host * inum)146 static struct dentry *gfs2_get_dentry(struct super_block *sb,
147 struct gfs2_inum_host *inum)
148 {
149 struct gfs2_sbd *sdp = sb->s_fs_info;
150 struct gfs2_holder i_gh, ri_gh, rgd_gh;
151 struct gfs2_rgrpd *rgd;
152 struct inode *inode;
153 struct dentry *dentry;
154 int error;
155
156 /* System files? */
157
158 inode = gfs2_ilookup(sb, inum->no_addr);
159 if (inode) {
160 if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
161 iput(inode);
162 return ERR_PTR(-ESTALE);
163 }
164 goto out_inode;
165 }
166
167 error = gfs2_glock_nq_num(sdp, inum->no_addr, &gfs2_inode_glops,
168 LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
169 if (error)
170 return ERR_PTR(error);
171
172 error = gfs2_rindex_hold(sdp, &ri_gh);
173 if (error)
174 goto fail;
175
176 error = -EINVAL;
177 rgd = gfs2_blk2rgrpd(sdp, inum->no_addr);
178 if (!rgd)
179 goto fail_rindex;
180
181 error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
182 if (error)
183 goto fail_rindex;
184
185 error = -ESTALE;
186 if (gfs2_get_block_type(rgd, inum->no_addr) != GFS2_BLKST_DINODE)
187 goto fail_rgd;
188
189 gfs2_glock_dq_uninit(&rgd_gh);
190 gfs2_glock_dq_uninit(&ri_gh);
191
192 inode = gfs2_inode_lookup(sb, DT_UNKNOWN,
193 inum->no_addr,
194 0, 0);
195 if (IS_ERR(inode)) {
196 error = PTR_ERR(inode);
197 goto fail;
198 }
199
200 error = gfs2_inode_refresh(GFS2_I(inode));
201 if (error) {
202 iput(inode);
203 goto fail;
204 }
205
206 /* Pick up the works we bypass in gfs2_inode_lookup */
207 if (inode->i_state & I_NEW)
208 gfs2_set_iop(inode);
209
210 if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
211 iput(inode);
212 goto fail;
213 }
214
215 error = -EIO;
216 if (GFS2_I(inode)->i_diskflags & GFS2_DIF_SYSTEM) {
217 iput(inode);
218 goto fail;
219 }
220
221 gfs2_glock_dq_uninit(&i_gh);
222
223 out_inode:
224 dentry = d_obtain_alias(inode);
225 if (!IS_ERR(dentry))
226 dentry->d_op = &gfs2_dops;
227 return dentry;
228
229 fail_rgd:
230 gfs2_glock_dq_uninit(&rgd_gh);
231
232 fail_rindex:
233 gfs2_glock_dq_uninit(&ri_gh);
234
235 fail:
236 gfs2_glock_dq_uninit(&i_gh);
237 return ERR_PTR(error);
238 }
239
gfs2_fh_to_dentry(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)240 static struct dentry *gfs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
241 int fh_len, int fh_type)
242 {
243 struct gfs2_inum_host this;
244 __be32 *fh = (__force __be32 *)fid->raw;
245
246 switch (fh_type) {
247 case GFS2_SMALL_FH_SIZE:
248 case GFS2_LARGE_FH_SIZE:
249 case GFS2_OLD_FH_SIZE:
250 this.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
251 this.no_formal_ino |= be32_to_cpu(fh[1]);
252 this.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
253 this.no_addr |= be32_to_cpu(fh[3]);
254 return gfs2_get_dentry(sb, &this);
255 default:
256 return NULL;
257 }
258 }
259
gfs2_fh_to_parent(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)260 static struct dentry *gfs2_fh_to_parent(struct super_block *sb, struct fid *fid,
261 int fh_len, int fh_type)
262 {
263 struct gfs2_inum_host parent;
264 __be32 *fh = (__force __be32 *)fid->raw;
265
266 switch (fh_type) {
267 case GFS2_LARGE_FH_SIZE:
268 case GFS2_OLD_FH_SIZE:
269 parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
270 parent.no_formal_ino |= be32_to_cpu(fh[5]);
271 parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
272 parent.no_addr |= be32_to_cpu(fh[7]);
273 return gfs2_get_dentry(sb, &parent);
274 default:
275 return NULL;
276 }
277 }
278
279 const struct export_operations gfs2_export_ops = {
280 .encode_fh = gfs2_encode_fh,
281 .fh_to_dentry = gfs2_fh_to_dentry,
282 .fh_to_parent = gfs2_fh_to_parent,
283 .get_name = gfs2_get_name,
284 .get_parent = gfs2_get_parent,
285 };
286
287