GFS2: Wait for unlock completion on umount
[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/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
18 #include "gfs2.h"
19 #include "incore.h"
20 #include "dir.h"
21 #include "glock.h"
22 #include "glops.h"
23 #include "inode.h"
24 #include "super.h"
25 #include "rgrp.h"
26 #include "util.h"
27
28 #define GFS2_SMALL_FH_SIZE 4
29 #define GFS2_LARGE_FH_SIZE 8
30 #define GFS2_OLD_FH_SIZE 10
31
32 static int gfs2_encode_fh(struct dentry *dentry, __u32 *p, int *len,
33                           int connectable)
34 {
35         __be32 *fh = (__force __be32 *)p;
36         struct inode *inode = dentry->d_inode;
37         struct super_block *sb = inode->i_sb;
38         struct gfs2_inode *ip = GFS2_I(inode);
39
40         if (*len < GFS2_SMALL_FH_SIZE ||
41             (connectable && *len < GFS2_LARGE_FH_SIZE))
42                 return 255;
43
44         fh[0] = cpu_to_be32(ip->i_no_formal_ino >> 32);
45         fh[1] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
46         fh[2] = cpu_to_be32(ip->i_no_addr >> 32);
47         fh[3] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
48         *len = GFS2_SMALL_FH_SIZE;
49
50         if (!connectable || inode == sb->s_root->d_inode)
51                 return *len;
52
53         spin_lock(&dentry->d_lock);
54         inode = dentry->d_parent->d_inode;
55         ip = GFS2_I(inode);
56         igrab(inode);
57         spin_unlock(&dentry->d_lock);
58
59         fh[4] = cpu_to_be32(ip->i_no_formal_ino >> 32);
60         fh[5] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
61         fh[6] = cpu_to_be32(ip->i_no_addr >> 32);
62         fh[7] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
63         *len = GFS2_LARGE_FH_SIZE;
64
65         iput(inode);
66
67         return *len;
68 }
69
70 struct get_name_filldir {
71         struct gfs2_inum_host inum;
72         char *name;
73 };
74
75 static int get_name_filldir(void *opaque, const char *name, int length,
76                             loff_t offset, u64 inum, unsigned int type)
77 {
78         struct get_name_filldir *gnfd = opaque;
79
80         if (inum != gnfd->inum.no_addr)
81                 return 0;
82
83         memcpy(gnfd->name, name, length);
84         gnfd->name[length] = 0;
85
86         return 1;
87 }
88
89 static int gfs2_get_name(struct dentry *parent, char *name,
90                          struct dentry *child)
91 {
92         struct inode *dir = parent->d_inode;
93         struct inode *inode = child->d_inode;
94         struct gfs2_inode *dip, *ip;
95         struct get_name_filldir gnfd;
96         struct gfs2_holder gh;
97         u64 offset = 0;
98         int error;
99
100         if (!dir)
101                 return -EINVAL;
102
103         if (!S_ISDIR(dir->i_mode) || !inode)
104                 return -EINVAL;
105
106         dip = GFS2_I(dir);
107         ip = GFS2_I(inode);
108
109         *name = 0;
110         gnfd.inum.no_addr = ip->i_no_addr;
111         gnfd.inum.no_formal_ino = ip->i_no_formal_ino;
112         gnfd.name = name;
113
114         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
115         if (error)
116                 return error;
117
118         error = gfs2_dir_read(dir, &offset, &gnfd, get_name_filldir);
119
120         gfs2_glock_dq_uninit(&gh);
121
122         if (!error && !*name)
123                 error = -ENOENT;
124
125         return error;
126 }
127
128 static struct dentry *gfs2_get_parent(struct dentry *child)
129 {
130         struct qstr dotdot;
131         struct dentry *dentry;
132
133         /*
134          * XXX(hch): it would be a good idea to keep this around as a
135          *           static variable.
136          */
137         gfs2_str2qstr(&dotdot, "..");
138
139         dentry = d_obtain_alias(gfs2_lookupi(child->d_inode, &dotdot, 1));
140         if (!IS_ERR(dentry))
141                 dentry->d_op = &gfs2_dops;
142         return dentry;
143 }
144
145 static struct dentry *gfs2_get_dentry(struct super_block *sb,
146                                       struct gfs2_inum_host *inum)
147 {
148         struct gfs2_sbd *sdp = sb->s_fs_info;
149         struct gfs2_holder i_gh;
150         struct inode *inode;
151         struct dentry *dentry;
152         int error;
153
154         inode = gfs2_ilookup(sb, inum->no_addr);
155         if (inode) {
156                 if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
157                         iput(inode);
158                         return ERR_PTR(-ESTALE);
159                 }
160                 goto out_inode;
161         }
162
163         error = gfs2_glock_nq_num(sdp, inum->no_addr, &gfs2_inode_glops,
164                                   LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
165         if (error)
166                 return ERR_PTR(error);
167
168         error = gfs2_check_blk_type(sdp, inum->no_addr, GFS2_BLKST_DINODE);
169         if (error)
170                 goto fail;
171
172         inode = gfs2_inode_lookup(sb, DT_UNKNOWN, inum->no_addr, 0, 0);
173         if (IS_ERR(inode)) {
174                 error = PTR_ERR(inode);
175                 goto fail;
176         }
177
178         error = gfs2_inode_refresh(GFS2_I(inode));
179         if (error) {
180                 iput(inode);
181                 goto fail;
182         }
183
184         /* Pick up the works we bypass in gfs2_inode_lookup */
185         if (inode->i_state & I_NEW) 
186                 gfs2_set_iop(inode);
187
188         if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
189                 iput(inode);
190                 goto fail;
191         }
192
193         error = -EIO;
194         if (GFS2_I(inode)->i_diskflags & GFS2_DIF_SYSTEM) {
195                 iput(inode);
196                 goto fail;
197         }
198
199         gfs2_glock_dq_uninit(&i_gh);
200
201 out_inode:
202         dentry = d_obtain_alias(inode);
203         if (!IS_ERR(dentry))
204                 dentry->d_op = &gfs2_dops;
205         return dentry;
206 fail:
207         gfs2_glock_dq_uninit(&i_gh);
208         return ERR_PTR(error);
209 }
210
211 static struct dentry *gfs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
212                 int fh_len, int fh_type)
213 {
214         struct gfs2_inum_host this;
215         __be32 *fh = (__force __be32 *)fid->raw;
216
217         switch (fh_type) {
218         case GFS2_SMALL_FH_SIZE:
219         case GFS2_LARGE_FH_SIZE:
220         case GFS2_OLD_FH_SIZE:
221                 this.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
222                 this.no_formal_ino |= be32_to_cpu(fh[1]);
223                 this.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
224                 this.no_addr |= be32_to_cpu(fh[3]);
225                 return gfs2_get_dentry(sb, &this);
226         default:
227                 return NULL;
228         }
229 }
230
231 static struct dentry *gfs2_fh_to_parent(struct super_block *sb, struct fid *fid,
232                 int fh_len, int fh_type)
233 {
234         struct gfs2_inum_host parent;
235         __be32 *fh = (__force __be32 *)fid->raw;
236
237         switch (fh_type) {
238         case GFS2_LARGE_FH_SIZE:
239         case GFS2_OLD_FH_SIZE:
240                 parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
241                 parent.no_formal_ino |= be32_to_cpu(fh[5]);
242                 parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
243                 parent.no_addr |= be32_to_cpu(fh[7]);
244                 return gfs2_get_dentry(sb, &parent);
245         default:
246                 return NULL;
247         }
248 }
249
250 const struct export_operations gfs2_export_ops = {
251         .encode_fh = gfs2_encode_fh,
252         .fh_to_dentry = gfs2_fh_to_dentry,
253         .fh_to_parent = gfs2_fh_to_parent,
254         .get_name = gfs2_get_name,
255         .get_parent = gfs2_get_parent,
256 };
257