GNU Linux-libre 4.19.211-gnu1
[releases.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 inode *inode, __u32 *p, int *len,
32                           struct inode *parent)
33 {
34         __be32 *fh = (__force __be32 *)p;
35         struct super_block *sb = inode->i_sb;
36         struct gfs2_inode *ip = GFS2_I(inode);
37
38         if (parent && (*len < GFS2_LARGE_FH_SIZE)) {
39                 *len = GFS2_LARGE_FH_SIZE;
40                 return FILEID_INVALID;
41         } else if (*len < GFS2_SMALL_FH_SIZE) {
42                 *len = GFS2_SMALL_FH_SIZE;
43                 return FILEID_INVALID;
44         }
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 (!parent || inode == d_inode(sb->s_root))
53                 return *len;
54
55         ip = GFS2_I(parent);
56
57         fh[4] = cpu_to_be32(ip->i_no_formal_ino >> 32);
58         fh[5] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
59         fh[6] = cpu_to_be32(ip->i_no_addr >> 32);
60         fh[7] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
61         *len = GFS2_LARGE_FH_SIZE;
62
63         return *len;
64 }
65
66 struct get_name_filldir {
67         struct dir_context ctx;
68         struct gfs2_inum_host inum;
69         char *name;
70 };
71
72 static int get_name_filldir(struct dir_context *ctx, const char *name,
73                             int length, loff_t offset, u64 inum,
74                             unsigned int type)
75 {
76         struct get_name_filldir *gnfd =
77                 container_of(ctx, struct get_name_filldir, ctx);
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 = d_inode(parent);
92         struct inode *inode = d_inode(child);
93         struct gfs2_inode *dip, *ip;
94         struct get_name_filldir gnfd = {
95                 .ctx.actor = get_name_filldir,
96                 .name = name
97         };
98         struct gfs2_holder gh;
99         int error;
100         struct file_ra_state f_ra = { .start = 0 };
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
115         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
116         if (error)
117                 return error;
118
119         error = gfs2_dir_read(dir, &gnfd.ctx, &f_ra);
120
121         gfs2_glock_dq_uninit(&gh);
122
123         if (!error && !*name)
124                 error = -ENOENT;
125
126         return error;
127 }
128
129 static struct dentry *gfs2_get_parent(struct dentry *child)
130 {
131         return d_obtain_alias(gfs2_lookupi(d_inode(child), &gfs2_qdotdot, 1));
132 }
133
134 static struct dentry *gfs2_get_dentry(struct super_block *sb,
135                                       struct gfs2_inum_host *inum)
136 {
137         struct gfs2_sbd *sdp = sb->s_fs_info;
138         struct inode *inode;
139
140         inode = gfs2_lookup_by_inum(sdp, inum->no_addr, &inum->no_formal_ino,
141                                     GFS2_BLKST_DINODE);
142         if (IS_ERR(inode))
143                 return ERR_CAST(inode);
144         return d_obtain_alias(inode);
145 }
146
147 static struct dentry *gfs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
148                 int fh_len, int fh_type)
149 {
150         struct gfs2_inum_host this;
151         __be32 *fh = (__force __be32 *)fid->raw;
152
153         switch (fh_type) {
154         case GFS2_SMALL_FH_SIZE:
155         case GFS2_LARGE_FH_SIZE:
156         case GFS2_OLD_FH_SIZE:
157                 if (fh_len < GFS2_SMALL_FH_SIZE)
158                         return NULL;
159                 this.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
160                 this.no_formal_ino |= be32_to_cpu(fh[1]);
161                 this.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
162                 this.no_addr |= be32_to_cpu(fh[3]);
163                 return gfs2_get_dentry(sb, &this);
164         default:
165                 return NULL;
166         }
167 }
168
169 static struct dentry *gfs2_fh_to_parent(struct super_block *sb, struct fid *fid,
170                 int fh_len, int fh_type)
171 {
172         struct gfs2_inum_host parent;
173         __be32 *fh = (__force __be32 *)fid->raw;
174
175         switch (fh_type) {
176         case GFS2_LARGE_FH_SIZE:
177         case GFS2_OLD_FH_SIZE:
178                 if (fh_len < GFS2_LARGE_FH_SIZE)
179                         return NULL;
180                 parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
181                 parent.no_formal_ino |= be32_to_cpu(fh[5]);
182                 parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
183                 parent.no_addr |= be32_to_cpu(fh[7]);
184                 return gfs2_get_dentry(sb, &parent);
185         default:
186                 return NULL;
187         }
188 }
189
190 const struct export_operations gfs2_export_ops = {
191         .encode_fh = gfs2_encode_fh,
192         .fh_to_dentry = gfs2_fh_to_dentry,
193         .fh_to_parent = gfs2_fh_to_parent,
194         .get_name = gfs2_get_name,
195         .get_parent = gfs2_get_parent,
196 };
197