Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/dlm
[pandora-kernel.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 qstr dotdot;
130         struct dentry *dentry;
131
132         /*
133          * XXX(hch): it would be a good idea to keep this around as a
134          *           static variable.
135          */
136         gfs2_str2qstr(&dotdot, "..");
137
138         dentry = d_obtain_alias(gfs2_lookupi(child->d_inode, &dotdot, 1));
139         if (!IS_ERR(dentry))
140                 dentry->d_op = &gfs2_dops;
141         return dentry;
142 }
143
144 static struct dentry *gfs2_get_dentry(struct super_block *sb,
145                                       struct gfs2_inum_host *inum)
146 {
147         struct gfs2_sbd *sdp = sb->s_fs_info;
148         struct gfs2_holder i_gh;
149         struct inode *inode;
150         struct dentry *dentry;
151         int error;
152
153         inode = gfs2_ilookup(sb, inum->no_addr);
154         if (inode) {
155                 if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
156                         iput(inode);
157                         return ERR_PTR(-ESTALE);
158                 }
159                 goto out_inode;
160         }
161
162         error = gfs2_glock_nq_num(sdp, inum->no_addr, &gfs2_inode_glops,
163                                   LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
164         if (error)
165                 return ERR_PTR(error);
166
167         error = gfs2_check_blk_type(sdp, inum->no_addr, GFS2_BLKST_DINODE);
168         if (error)
169                 goto fail;
170
171         inode = gfs2_inode_lookup(sb, DT_UNKNOWN, inum->no_addr, 0, 0);
172         if (IS_ERR(inode)) {
173                 error = PTR_ERR(inode);
174                 goto fail;
175         }
176
177         error = gfs2_inode_refresh(GFS2_I(inode));
178         if (error) {
179                 iput(inode);
180                 goto fail;
181         }
182
183         /* Pick up the works we bypass in gfs2_inode_lookup */
184         if (inode->i_state & I_NEW) 
185                 gfs2_set_iop(inode);
186
187         if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
188                 iput(inode);
189                 goto fail;
190         }
191
192         error = -EIO;
193         if (GFS2_I(inode)->i_diskflags & GFS2_DIF_SYSTEM) {
194                 iput(inode);
195                 goto fail;
196         }
197
198         gfs2_glock_dq_uninit(&i_gh);
199
200 out_inode:
201         dentry = d_obtain_alias(inode);
202         if (!IS_ERR(dentry))
203                 dentry->d_op = &gfs2_dops;
204         return dentry;
205 fail:
206         gfs2_glock_dq_uninit(&i_gh);
207         return ERR_PTR(error);
208 }
209
210 static struct dentry *gfs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
211                 int fh_len, int fh_type)
212 {
213         struct gfs2_inum_host this;
214         __be32 *fh = (__force __be32 *)fid->raw;
215
216         switch (fh_type) {
217         case GFS2_SMALL_FH_SIZE:
218         case GFS2_LARGE_FH_SIZE:
219         case GFS2_OLD_FH_SIZE:
220                 this.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
221                 this.no_formal_ino |= be32_to_cpu(fh[1]);
222                 this.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
223                 this.no_addr |= be32_to_cpu(fh[3]);
224                 return gfs2_get_dentry(sb, &this);
225         default:
226                 return NULL;
227         }
228 }
229
230 static struct dentry *gfs2_fh_to_parent(struct super_block *sb, struct fid *fid,
231                 int fh_len, int fh_type)
232 {
233         struct gfs2_inum_host parent;
234         __be32 *fh = (__force __be32 *)fid->raw;
235
236         switch (fh_type) {
237         case GFS2_LARGE_FH_SIZE:
238         case GFS2_OLD_FH_SIZE:
239                 parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
240                 parent.no_formal_ino |= be32_to_cpu(fh[5]);
241                 parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
242                 parent.no_addr |= be32_to_cpu(fh[7]);
243                 return gfs2_get_dentry(sb, &parent);
244         default:
245                 return NULL;
246         }
247 }
248
249 const struct export_operations gfs2_export_ops = {
250         .encode_fh = gfs2_encode_fh,
251         .fh_to_dentry = gfs2_fh_to_dentry,
252         .fh_to_parent = gfs2_fh_to_parent,
253         .get_name = gfs2_get_name,
254         .get_parent = gfs2_get_parent,
255 };
256