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 "ops_dentry.h"
26 #include "ops_fstype.h"
27 #include "rgrp.h"
28 #include "util.h"
29
30 #define GFS2_SMALL_FH_SIZE 4
31 #define GFS2_LARGE_FH_SIZE 8
32 #define GFS2_OLD_FH_SIZE 10
33
34 static int gfs2_encode_fh(struct dentry *dentry, __u32 *p, int *len,
35 int connectable)
36 {
37 __be32 *fh = (__force __be32 *)p;
38 struct inode *inode = dentry->d_inode;
39 struct super_block *sb = inode->i_sb;
40 struct gfs2_inode *ip = GFS2_I(inode);
41
42 if (*len < GFS2_SMALL_FH_SIZE ||
43 (connectable && *len < GFS2_LARGE_FH_SIZE))
44 return 255;
45
46 fh[0] = cpu_to_be32(ip->i_no_formal_ino >> 32);
47 fh[1] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
48 fh[2] = cpu_to_be32(ip->i_no_addr >> 32);
49 fh[3] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
50 *len = GFS2_SMALL_FH_SIZE;
51
52 if (!connectable || inode == sb->s_root->d_inode)
53 return *len;
54
55 spin_lock(&dentry->d_lock);
56 inode = dentry->d_parent->d_inode;
57 ip = GFS2_I(inode);
58 igrab(inode);
59 spin_unlock(&dentry->d_lock);
60
61 fh[4] = cpu_to_be32(ip->i_no_formal_ino >> 32);
62 fh[5] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
63 fh[6] = cpu_to_be32(ip->i_no_addr >> 32);
64 fh[7] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
65 *len = GFS2_LARGE_FH_SIZE;
66
67 iput(inode);
68
69 return *len;
70 }
71
72 struct get_name_filldir {
73 struct gfs2_inum_host inum;
74 char *name;
75 };
76
77 static int get_name_filldir(void *opaque, const char *name, int length,
78 loff_t offset, u64 inum, unsigned int type)
79 {
80 struct get_name_filldir *gnfd = opaque;
81
82 if (inum != gnfd->inum.no_addr)
83 return 0;
84
85 memcpy(gnfd->name, name, length);
86 gnfd->name[length] = 0;
87
88 return 1;
89 }
90
91 static int gfs2_get_name(struct dentry *parent, char *name,
92 struct dentry *child)
93 {
94 struct inode *dir = parent->d_inode;
95 struct inode *inode = child->d_inode;
96 struct gfs2_inode *dip, *ip;
97 struct get_name_filldir gnfd;
98 struct gfs2_holder gh;
99 u64 offset = 0;
100 int error;
101
102 if (!dir)
103 return -EINVAL;
104
105 if (!S_ISDIR(dir->i_mode) || !inode)
106 return -EINVAL;
107
108 dip = GFS2_I(dir);
109 ip = GFS2_I(inode);
110
111 *name = 0;
112 gnfd.inum.no_addr = ip->i_no_addr;
113 gnfd.inum.no_formal_ino = ip->i_no_formal_ino;
114 gnfd.name = name;
115
116 error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
117 if (error)
118 return error;
119
120 error = gfs2_dir_read(dir, &offset, &gnfd, get_name_filldir);
121
122 gfs2_glock_dq_uninit(&gh);
123
124 if (!error && !*name)
125 error = -ENOENT;
126
127 return error;
128 }
129
130 static struct dentry *gfs2_get_parent(struct dentry *child)
131 {
132 struct qstr dotdot;
133 struct inode *inode;
134 struct dentry *dentry;
135
136 gfs2_str2qstr(&dotdot, "..");
137 inode = gfs2_lookupi(child->d_inode, &dotdot, 1, NULL);
138
139 if (!inode)
140 return ERR_PTR(-ENOENT);
141 /*
142 * In case of an error, @inode carries the error value, and we
143 * have to return that as a(n invalid) pointer to dentry.
144 */
145 if (IS_ERR(inode))
146 return ERR_CAST(inode);
147
148 dentry = d_alloc_anon(inode);
149 if (!dentry) {
150 iput(inode);
151 return ERR_PTR(-ENOMEM);
152 }
153
154 dentry->d_op = &gfs2_dops;
155 return dentry;
156 }
157
158 static struct dentry *gfs2_get_dentry(struct super_block *sb,
159 struct gfs2_inum_host *inum)
160 {
161 struct gfs2_sbd *sdp = sb->s_fs_info;
162 struct gfs2_holder i_gh, ri_gh, rgd_gh;
163 struct gfs2_rgrpd *rgd;
164 struct inode *inode;
165 struct dentry *dentry;
166 int error;
167
168 /* System files? */
169
170 inode = gfs2_ilookup(sb, inum->no_addr);
171 if (inode) {
172 if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
173 iput(inode);
174 return ERR_PTR(-ESTALE);
175 }
176 goto out_inode;
177 }
178
179 error = gfs2_glock_nq_num(sdp, inum->no_addr, &gfs2_inode_glops,
180 LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
181 if (error)
182 return ERR_PTR(error);
183
184 error = gfs2_rindex_hold(sdp, &ri_gh);
185 if (error)
186 goto fail;
187
188 error = -EINVAL;
189 rgd = gfs2_blk2rgrpd(sdp, inum->no_addr);
190 if (!rgd)
191 goto fail_rindex;
192
193 error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
194 if (error)
195 goto fail_rindex;
196
197 error = -ESTALE;
198 if (gfs2_get_block_type(rgd, inum->no_addr) != GFS2_BLKST_DINODE)
199 goto fail_rgd;
200
201 gfs2_glock_dq_uninit(&rgd_gh);
202 gfs2_glock_dq_uninit(&ri_gh);
203
204 inode = gfs2_inode_lookup(sb, DT_UNKNOWN,
205 inum->no_addr,
206 0, 0);
207 if (!inode)
208 goto fail;
209 if (IS_ERR(inode)) {
210 error = PTR_ERR(inode);
211 goto fail;
212 }
213
214 error = gfs2_inode_refresh(GFS2_I(inode));
215 if (error) {
216 iput(inode);
217 goto fail;
218 }
219
220 /* Pick up the works we bypass in gfs2_inode_lookup */
221 if (inode->i_state & I_NEW)
222 gfs2_set_iop(inode);
223
224 if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
225 iput(inode);
226 goto fail;
227 }
228
229 error = -EIO;
230 if (GFS2_I(inode)->i_di.di_flags & GFS2_DIF_SYSTEM) {
231 iput(inode);
232 goto fail;
233 }
234
235 gfs2_glock_dq_uninit(&i_gh);
236
237 out_inode:
238 dentry = d_alloc_anon(inode);
239 if (!dentry) {
240 iput(inode);
241 return ERR_PTR(-ENOMEM);
242 }
243
244 dentry->d_op = &gfs2_dops;
245 return dentry;
246
247 fail_rgd:
248 gfs2_glock_dq_uninit(&rgd_gh);
249
250 fail_rindex:
251 gfs2_glock_dq_uninit(&ri_gh);
252
253 fail:
254 gfs2_glock_dq_uninit(&i_gh);
255 return ERR_PTR(error);
256 }
257
258 static struct dentry *gfs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
259 int fh_len, int fh_type)
260 {
261 struct gfs2_inum_host this;
262 __be32 *fh = (__force __be32 *)fid->raw;
263
264 switch (fh_type) {
265 case GFS2_SMALL_FH_SIZE:
266 case GFS2_LARGE_FH_SIZE:
267 case GFS2_OLD_FH_SIZE:
268 this.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
269 this.no_formal_ino |= be32_to_cpu(fh[1]);
270 this.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
271 this.no_addr |= be32_to_cpu(fh[3]);
272 return gfs2_get_dentry(sb, &this);
273 default:
274 return NULL;
275 }
276 }
277
278 static struct dentry *gfs2_fh_to_parent(struct super_block *sb, struct fid *fid,
279 int fh_len, int fh_type)
280 {
281 struct gfs2_inum_host parent;
282 __be32 *fh = (__force __be32 *)fid->raw;
283
284 switch (fh_type) {
285 case GFS2_LARGE_FH_SIZE:
286 case GFS2_OLD_FH_SIZE:
287 parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
288 parent.no_formal_ino |= be32_to_cpu(fh[5]);
289 parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
290 parent.no_addr |= be32_to_cpu(fh[7]);
291 return gfs2_get_dentry(sb, &parent);
292 default:
293 return NULL;
294 }
295 }
296
297 const struct export_operations gfs2_export_ops = {
298 .encode_fh = gfs2_encode_fh,
299 .fh_to_dentry = gfs2_fh_to_dentry,
300 .fh_to_parent = gfs2_fh_to_parent,
301 .get_name = gfs2_get_name,
302 .get_parent = gfs2_get_parent,
303 };
304
305
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