Convert ERR_PTR(PTR_ERR(p)) instances to ERR_CAST(p)
[linux-2.6.git] / fs / gfs2 / ops_export.c
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