sysfs: Fix oops in sysfs_drop_dentry on x86_64
[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/gfs2_ondisk.h>
15 #include <linux/crc32.h>
16 #include <linux/lm_interface.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 "ops_dentry.h"
25 #include "ops_fstype.h"
26 #include "rgrp.h"
27 #include "util.h"
28
29 #define GFS2_SMALL_FH_SIZE 4
30 #define GFS2_LARGE_FH_SIZE 8
31 #define GFS2_OLD_FH_SIZE 10
32
33 static struct dentry *gfs2_decode_fh(struct super_block *sb,
34                                      __u32 *p,
35                                      int fh_len,
36                                      int fh_type,
37                                      int (*acceptable)(void *context,
38                                                        struct dentry *dentry),
39                                      void *context)
40 {
41         __be32 *fh = (__force __be32 *)p;
42         struct gfs2_inum_host inum, parent;
43
44         memset(&parent, 0, sizeof(struct gfs2_inum));
45
46         switch (fh_len) {
47         case GFS2_LARGE_FH_SIZE:
48         case GFS2_OLD_FH_SIZE:
49                 parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
50                 parent.no_formal_ino |= be32_to_cpu(fh[5]);
51                 parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
52                 parent.no_addr |= be32_to_cpu(fh[7]);
53         case GFS2_SMALL_FH_SIZE:
54                 inum.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
55                 inum.no_formal_ino |= be32_to_cpu(fh[1]);
56                 inum.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
57                 inum.no_addr |= be32_to_cpu(fh[3]);
58                 break;
59         default:
60                 return NULL;
61         }
62
63         return gfs2_export_ops.find_exported_dentry(sb, &inum, &parent,
64                                                     acceptable, context);
65 }
66
67 static int gfs2_encode_fh(struct dentry *dentry, __u32 *p, int *len,
68                           int connectable)
69 {
70         __be32 *fh = (__force __be32 *)p;
71         struct inode *inode = dentry->d_inode;
72         struct super_block *sb = inode->i_sb;
73         struct gfs2_inode *ip = GFS2_I(inode);
74
75         if (*len < GFS2_SMALL_FH_SIZE ||
76             (connectable && *len < GFS2_LARGE_FH_SIZE))
77                 return 255;
78
79         fh[0] = cpu_to_be32(ip->i_no_formal_ino >> 32);
80         fh[1] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
81         fh[2] = cpu_to_be32(ip->i_no_addr >> 32);
82         fh[3] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
83         *len = GFS2_SMALL_FH_SIZE;
84
85         if (!connectable || inode == sb->s_root->d_inode)
86                 return *len;
87
88         spin_lock(&dentry->d_lock);
89         inode = dentry->d_parent->d_inode;
90         ip = GFS2_I(inode);
91         igrab(inode);
92         spin_unlock(&dentry->d_lock);
93
94         fh[4] = cpu_to_be32(ip->i_no_formal_ino >> 32);
95         fh[5] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
96         fh[6] = cpu_to_be32(ip->i_no_addr >> 32);
97         fh[7] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
98         *len = GFS2_LARGE_FH_SIZE;
99
100         iput(inode);
101
102         return *len;
103 }
104
105 struct get_name_filldir {
106         struct gfs2_inum_host inum;
107         char *name;
108 };
109
110 static int get_name_filldir(void *opaque, const char *name, int length,
111                             loff_t offset, u64 inum, unsigned int type)
112 {
113         struct get_name_filldir *gnfd = opaque;
114
115         if (inum != gnfd->inum.no_addr)
116                 return 0;
117
118         memcpy(gnfd->name, name, length);
119         gnfd->name[length] = 0;
120
121         return 1;
122 }
123
124 static int gfs2_get_name(struct dentry *parent, char *name,
125                          struct dentry *child)
126 {
127         struct inode *dir = parent->d_inode;
128         struct inode *inode = child->d_inode;
129         struct gfs2_inode *dip, *ip;
130         struct get_name_filldir gnfd;
131         struct gfs2_holder gh;
132         u64 offset = 0;
133         int error;
134
135         if (!dir)
136                 return -EINVAL;
137
138         if (!S_ISDIR(dir->i_mode) || !inode)
139                 return -EINVAL;
140
141         dip = GFS2_I(dir);
142         ip = GFS2_I(inode);
143
144         *name = 0;
145         gnfd.inum.no_addr = ip->i_no_addr;
146         gnfd.inum.no_formal_ino = ip->i_no_formal_ino;
147         gnfd.name = name;
148
149         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
150         if (error)
151                 return error;
152
153         error = gfs2_dir_read(dir, &offset, &gnfd, get_name_filldir);
154
155         gfs2_glock_dq_uninit(&gh);
156
157         if (!error && !*name)
158                 error = -ENOENT;
159
160         return error;
161 }
162
163 static struct dentry *gfs2_get_parent(struct dentry *child)
164 {
165         struct qstr dotdot;
166         struct inode *inode;
167         struct dentry *dentry;
168
169         gfs2_str2qstr(&dotdot, "..");
170         inode = gfs2_lookupi(child->d_inode, &dotdot, 1, NULL);
171
172         if (!inode)
173                 return ERR_PTR(-ENOENT);
174         /*
175          * In case of an error, @inode carries the error value, and we
176          * have to return that as a(n invalid) pointer to dentry.
177          */
178         if (IS_ERR(inode))
179                 return ERR_PTR(PTR_ERR(inode));
180
181         dentry = d_alloc_anon(inode);
182         if (!dentry) {
183                 iput(inode);
184                 return ERR_PTR(-ENOMEM);
185         }
186
187         dentry->d_op = &gfs2_dops;
188         return dentry;
189 }
190
191 static struct dentry *gfs2_get_dentry(struct super_block *sb, void *inum_obj)
192 {
193         struct gfs2_sbd *sdp = sb->s_fs_info;
194         struct gfs2_inum_host *inum = inum_obj;
195         struct gfs2_holder i_gh, ri_gh, rgd_gh;
196         struct gfs2_rgrpd *rgd;
197         struct inode *inode;
198         struct dentry *dentry;
199         int error;
200
201         /* System files? */
202
203         inode = gfs2_ilookup(sb, inum->no_addr);
204         if (inode) {
205                 if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
206                         iput(inode);
207                         return ERR_PTR(-ESTALE);
208                 }
209                 goto out_inode;
210         }
211
212         error = gfs2_glock_nq_num(sdp, inum->no_addr, &gfs2_inode_glops,
213                                   LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
214         if (error)
215                 return ERR_PTR(error);
216
217         error = gfs2_rindex_hold(sdp, &ri_gh);
218         if (error)
219                 goto fail;
220
221         error = -EINVAL;
222         rgd = gfs2_blk2rgrpd(sdp, inum->no_addr);
223         if (!rgd)
224                 goto fail_rindex;
225
226         error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
227         if (error)
228                 goto fail_rindex;
229
230         error = -ESTALE;
231         if (gfs2_get_block_type(rgd, inum->no_addr) != GFS2_BLKST_DINODE)
232                 goto fail_rgd;
233
234         gfs2_glock_dq_uninit(&rgd_gh);
235         gfs2_glock_dq_uninit(&ri_gh);
236
237         inode = gfs2_inode_lookup(sb, DT_UNKNOWN,
238                                         inum->no_addr,
239                                         0);
240         if (!inode)
241                 goto fail;
242         if (IS_ERR(inode)) {
243                 error = PTR_ERR(inode);
244                 goto fail;
245         }
246
247         error = gfs2_inode_refresh(GFS2_I(inode));
248         if (error) {
249                 iput(inode);
250                 goto fail;
251         }
252
253         /* Pick up the works we bypass in gfs2_inode_lookup */
254         if (inode->i_state & I_NEW) 
255                 gfs2_set_iop(inode);
256
257         if (GFS2_I(inode)->i_no_formal_ino != inum->no_formal_ino) {
258                 iput(inode);
259                 goto fail;
260         }
261
262         error = -EIO;
263         if (GFS2_I(inode)->i_di.di_flags & GFS2_DIF_SYSTEM) {
264                 iput(inode);
265                 goto fail;
266         }
267
268         gfs2_glock_dq_uninit(&i_gh);
269
270 out_inode:
271         dentry = d_alloc_anon(inode);
272         if (!dentry) {
273                 iput(inode);
274                 return ERR_PTR(-ENOMEM);
275         }
276
277         dentry->d_op = &gfs2_dops;
278         return dentry;
279
280 fail_rgd:
281         gfs2_glock_dq_uninit(&rgd_gh);
282
283 fail_rindex:
284         gfs2_glock_dq_uninit(&ri_gh);
285
286 fail:
287         gfs2_glock_dq_uninit(&i_gh);
288         return ERR_PTR(error);
289 }
290
291 struct export_operations gfs2_export_ops = {
292         .decode_fh = gfs2_decode_fh,
293         .encode_fh = gfs2_encode_fh,
294         .get_name = gfs2_get_name,
295         .get_parent = gfs2_get_parent,
296         .get_dentry = gfs2_get_dentry,
297 };
298