Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael...
[linux-2.6.git] / fs / gfs2 / 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/spinlock.h>
11 #include <linux/completion.h>
12 #include <linux/buffer_head.h>
13 #include <linux/exportfs.h>
14 #include <linux/gfs2_ondisk.h>
15 #include <linux/crc32.h>
16
17 #include "gfs2.h"
18 #include "incore.h"
19 #include "dir.h"
20 #include "glock.h"
21 #include "glops.h"
22 #include "inode.h"
23 #include "super.h"
24 #include "rgrp.h"
25 #include "util.h"
26
27 #define GFS2_SMALL_FH_SIZE 4
28 #define GFS2_LARGE_FH_SIZE 8
29 #define GFS2_OLD_FH_SIZE 10
30
31 static int gfs2_encode_fh(struct dentry *dentry, __u32 *p, int *len,
32                           int connectable)
33 {
34         __be32 *fh = (__force __be32 *)p;
35         struct inode *inode = dentry->d_inode;
36         struct super_block *sb = inode->i_sb;
37         struct gfs2_inode *ip = GFS2_I(inode);
38
39         if (*len < GFS2_SMALL_FH_SIZE ||
40             (connectable && *len < GFS2_LARGE_FH_SIZE))
41                 return 255;
42
43         fh[0] = cpu_to_be32(ip->i_no_formal_ino >> 32);
44         fh[1] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
45         fh[2] = cpu_to_be32(ip->i_no_addr >> 32);
46         fh[3] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
47         *len = GFS2_SMALL_FH_SIZE;
48
49         if (!connectable || inode == sb->s_root->d_inode)
50                 return *len;
51
52         spin_lock(&dentry->d_lock);
53         inode = dentry->d_parent->d_inode;
54         ip = GFS2_I(inode);
55         igrab(inode);
56         spin_unlock(&dentry->d_lock);
57
58         fh[4] = cpu_to_be32(ip->i_no_formal_ino >> 32);
59         fh[5] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
60         fh[6] = cpu_to_be32(ip->i_no_addr >> 32);
61         fh[7] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
62         *len = GFS2_LARGE_FH_SIZE;
63
64         iput(inode);
65
66         return *len;
67 }
68
69 struct get_name_filldir {
70         struct gfs2_inum_host inum;
71         char *name;
72 };
73
74 static int get_name_filldir(void *opaque, const char *name, int length,
75                             loff_t offset, u64 inum, unsigned int type)
76 {
77         struct get_name_filldir *gnfd = opaque;
78
79         if (inum != gnfd->inum.no_addr)
80                 return 0;
81
82         memcpy(gnfd->name, name, length);
83         gnfd->name[length] = 0;
84
85         return 1;
86 }
87
88 static int gfs2_get_name(struct dentry *parent, char *name,
89                          struct dentry *child)
90 {
91         struct inode *dir = parent->d_inode;
92         struct inode *inode = child->d_inode;
93         struct gfs2_inode *dip, *ip;
94         struct get_name_filldir gnfd;
95         struct gfs2_holder gh;
96         u64 offset = 0;
97         int error;
98
99         if (!dir)
100                 return -EINVAL;
101
102         if (!S_ISDIR(dir->i_mode) || !inode)
103                 return -EINVAL;
104
105         dip = GFS2_I(dir);
106         ip = GFS2_I(inode);
107
108         *name = 0;
109         gnfd.inum.no_addr = ip->i_no_addr;
110         gnfd.inum.no_formal_ino = ip->i_no_formal_ino;
111         gnfd.name = name;
112
113         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
114         if (error)
115                 return error;
116
117         error = gfs2_dir_read(dir, &offset, &gnfd, get_name_filldir);
118
119         gfs2_glock_dq_uninit(&gh);
120
121         if (!error && !*name)
122                 error = -ENOENT;
123
124         return error;
125 }
126
127 static struct dentry *gfs2_get_parent(struct dentry *child)
128 {
129         struct dentry *dentry;
130
131         dentry = d_obtain_alias(gfs2_lookupi(child->d_inode, &gfs2_qdotdot, 1));
132         if (!IS_ERR(dentry))
133                 dentry->d_op = &gfs2_dops;
134         return dentry;
135 }
136
137 static struct dentry *gfs2_get_dentry(struct super_block *sb,
138                                       struct gfs2_inum_host *inum)
139 {
140         struct gfs2_sbd *sdp = sb->s_fs_info;
141         struct gfs2_holder i_gh;
142         struct inode *inode;
143         struct dentry *dentry;
144         int error;
145
146         inode = gfs2_ilookup(sb, inum->no_addr);
147         if (inode) {
148                 if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
149                         iput(inode);
150                         return ERR_PTR(-ESTALE);
151                 }
152                 goto out_inode;
153         }
154
155         error = gfs2_glock_nq_num(sdp, inum->no_addr, &gfs2_inode_glops,
156                                   LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
157         if (error)
158                 return ERR_PTR(error);
159
160         error = gfs2_check_blk_type(sdp, inum->no_addr, GFS2_BLKST_DINODE);
161         if (error)
162                 goto fail;
163
164         inode = gfs2_inode_lookup(sb, DT_UNKNOWN, inum->no_addr, 0);
165         if (IS_ERR(inode)) {
166                 error = PTR_ERR(inode);
167                 goto fail;
168         }
169
170         error = gfs2_inode_refresh(GFS2_I(inode));
171         if (error) {
172                 iput(inode);
173                 goto fail;
174         }
175
176         /* Pick up the works we bypass in gfs2_inode_lookup */
177         if (inode->i_state & I_NEW) 
178                 gfs2_set_iop(inode);
179
180         if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
181                 iput(inode);
182                 goto fail;
183         }
184
185         error = -EIO;
186         if (GFS2_I(inode)->i_diskflags & GFS2_DIF_SYSTEM) {
187                 iput(inode);
188                 goto fail;
189         }
190
191         gfs2_glock_dq_uninit(&i_gh);
192
193 out_inode:
194         dentry = d_obtain_alias(inode);
195         if (!IS_ERR(dentry))
196                 dentry->d_op = &gfs2_dops;
197         return dentry;
198 fail:
199         gfs2_glock_dq_uninit(&i_gh);
200         return ERR_PTR(error);
201 }
202
203 static struct dentry *gfs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
204                 int fh_len, int fh_type)
205 {
206         struct gfs2_inum_host this;
207         __be32 *fh = (__force __be32 *)fid->raw;
208
209         switch (fh_type) {
210         case GFS2_SMALL_FH_SIZE:
211         case GFS2_LARGE_FH_SIZE:
212         case GFS2_OLD_FH_SIZE:
213                 this.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
214                 this.no_formal_ino |= be32_to_cpu(fh[1]);
215                 this.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
216                 this.no_addr |= be32_to_cpu(fh[3]);
217                 return gfs2_get_dentry(sb, &this);
218         default:
219                 return NULL;
220         }
221 }
222
223 static struct dentry *gfs2_fh_to_parent(struct super_block *sb, struct fid *fid,
224                 int fh_len, int fh_type)
225 {
226         struct gfs2_inum_host parent;
227         __be32 *fh = (__force __be32 *)fid->raw;
228
229         switch (fh_type) {
230         case GFS2_LARGE_FH_SIZE:
231         case GFS2_OLD_FH_SIZE:
232                 parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
233                 parent.no_formal_ino |= be32_to_cpu(fh[5]);
234                 parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
235                 parent.no_addr |= be32_to_cpu(fh[7]);
236                 return gfs2_get_dentry(sb, &parent);
237         default:
238                 return NULL;
239         }
240 }
241
242 const struct export_operations gfs2_export_ops = {
243         .encode_fh = gfs2_encode_fh,
244         .fh_to_dentry = gfs2_fh_to_dentry,
245         .fh_to_parent = gfs2_fh_to_parent,
246         .get_name = gfs2_get_name,
247         .get_parent = gfs2_get_parent,
248 };
249