Merge commit 'v2.6.28-rc4' into timers/rtc
[linux-2.6] / 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 dentry *dentry;
134
135         /*
136          * XXX(hch): it would be a good idea to keep this around as a
137          *           static variable.
138          */
139         gfs2_str2qstr(&dotdot, "..");
140
141         dentry = d_obtain_alias(gfs2_lookupi(child->d_inode, &dotdot, 1));
142         if (!IS_ERR(dentry))
143                 dentry->d_op = &gfs2_dops;
144         return dentry;
145 }
146
147 static struct dentry *gfs2_get_dentry(struct super_block *sb,
148                 struct gfs2_inum_host *inum)
149 {
150         struct gfs2_sbd *sdp = sb->s_fs_info;
151         struct gfs2_holder i_gh, ri_gh, rgd_gh;
152         struct gfs2_rgrpd *rgd;
153         struct inode *inode;
154         struct dentry *dentry;
155         int error;
156
157         /* System files? */
158
159         inode = gfs2_ilookup(sb, inum->no_addr);
160         if (inode) {
161                 if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
162                         iput(inode);
163                         return ERR_PTR(-ESTALE);
164                 }
165                 goto out_inode;
166         }
167
168         error = gfs2_glock_nq_num(sdp, inum->no_addr, &gfs2_inode_glops,
169                                   LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
170         if (error)
171                 return ERR_PTR(error);
172
173         error = gfs2_rindex_hold(sdp, &ri_gh);
174         if (error)
175                 goto fail;
176
177         error = -EINVAL;
178         rgd = gfs2_blk2rgrpd(sdp, inum->no_addr);
179         if (!rgd)
180                 goto fail_rindex;
181
182         error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
183         if (error)
184                 goto fail_rindex;
185
186         error = -ESTALE;
187         if (gfs2_get_block_type(rgd, inum->no_addr) != GFS2_BLKST_DINODE)
188                 goto fail_rgd;
189
190         gfs2_glock_dq_uninit(&rgd_gh);
191         gfs2_glock_dq_uninit(&ri_gh);
192
193         inode = gfs2_inode_lookup(sb, DT_UNKNOWN,
194                                         inum->no_addr,
195                                         0, 0);
196         if (IS_ERR(inode)) {
197                 error = PTR_ERR(inode);
198                 goto fail;
199         }
200
201         error = gfs2_inode_refresh(GFS2_I(inode));
202         if (error) {
203                 iput(inode);
204                 goto fail;
205         }
206
207         /* Pick up the works we bypass in gfs2_inode_lookup */
208         if (inode->i_state & I_NEW) 
209                 gfs2_set_iop(inode);
210
211         if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
212                 iput(inode);
213                 goto fail;
214         }
215
216         error = -EIO;
217         if (GFS2_I(inode)->i_di.di_flags & GFS2_DIF_SYSTEM) {
218                 iput(inode);
219                 goto fail;
220         }
221
222         gfs2_glock_dq_uninit(&i_gh);
223
224 out_inode:
225         dentry = d_obtain_alias(inode);
226         if (!IS_ERR(dentry))
227                 dentry->d_op = &gfs2_dops;
228         return dentry;
229
230 fail_rgd:
231         gfs2_glock_dq_uninit(&rgd_gh);
232
233 fail_rindex:
234         gfs2_glock_dq_uninit(&ri_gh);
235
236 fail:
237         gfs2_glock_dq_uninit(&i_gh);
238         return ERR_PTR(error);
239 }
240
241 static struct dentry *gfs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
242                 int fh_len, int fh_type)
243 {
244         struct gfs2_inum_host this;
245         __be32 *fh = (__force __be32 *)fid->raw;
246
247         switch (fh_type) {
248         case GFS2_SMALL_FH_SIZE:
249         case GFS2_LARGE_FH_SIZE:
250         case GFS2_OLD_FH_SIZE:
251                 this.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
252                 this.no_formal_ino |= be32_to_cpu(fh[1]);
253                 this.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
254                 this.no_addr |= be32_to_cpu(fh[3]);
255                 return gfs2_get_dentry(sb, &this);
256         default:
257                 return NULL;
258         }
259 }
260
261 static struct dentry *gfs2_fh_to_parent(struct super_block *sb, struct fid *fid,
262                 int fh_len, int fh_type)
263 {
264         struct gfs2_inum_host parent;
265         __be32 *fh = (__force __be32 *)fid->raw;
266
267         switch (fh_type) {
268         case GFS2_LARGE_FH_SIZE:
269         case GFS2_OLD_FH_SIZE:
270                 parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
271                 parent.no_formal_ino |= be32_to_cpu(fh[5]);
272                 parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
273                 parent.no_addr |= be32_to_cpu(fh[7]);
274                 return gfs2_get_dentry(sb, &parent);
275         default:
276                 return NULL;
277         }
278 }
279
280 const struct export_operations gfs2_export_ops = {
281         .encode_fh = gfs2_encode_fh,
282         .fh_to_dentry = gfs2_fh_to_dentry,
283         .fh_to_parent = gfs2_fh_to_parent,
284         .get_name = gfs2_get_name,
285         .get_parent = gfs2_get_parent,
286 };
287