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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
4 * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
5 */
6
7#include <linux/spinlock.h>
8#include <linux/completion.h>
9#include <linux/buffer_head.h>
10#include <linux/exportfs.h>
11#include <linux/gfs2_ondisk.h>
12#include <linux/crc32.h>
13
14#include "gfs2.h"
15#include "incore.h"
16#include "dir.h"
17#include "glock.h"
18#include "glops.h"
19#include "inode.h"
20#include "super.h"
21#include "rgrp.h"
22#include "util.h"
23
24#define GFS2_SMALL_FH_SIZE 4
25#define GFS2_LARGE_FH_SIZE 8
26#define GFS2_OLD_FH_SIZE 10
27
28static int gfs2_encode_fh(struct inode *inode, __u32 *p, int *len,
29 struct inode *parent)
30{
31 __be32 *fh = (__force __be32 *)p;
32 struct super_block *sb = inode->i_sb;
33 struct gfs2_inode *ip = GFS2_I(inode);
34
35 if (parent && (*len < GFS2_LARGE_FH_SIZE)) {
36 *len = GFS2_LARGE_FH_SIZE;
37 return FILEID_INVALID;
38 } else if (*len < GFS2_SMALL_FH_SIZE) {
39 *len = GFS2_SMALL_FH_SIZE;
40 return FILEID_INVALID;
41 }
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 (!parent || inode == d_inode(sb->s_root))
50 return *len;
51
52 ip = GFS2_I(parent);
53
54 fh[4] = cpu_to_be32(ip->i_no_formal_ino >> 32);
55 fh[5] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
56 fh[6] = cpu_to_be32(ip->i_no_addr >> 32);
57 fh[7] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
58 *len = GFS2_LARGE_FH_SIZE;
59
60 return *len;
61}
62
63struct get_name_filldir {
64 struct dir_context ctx;
65 struct gfs2_inum_host inum;
66 char *name;
67};
68
69static bool get_name_filldir(struct dir_context *ctx, const char *name,
70 int length, loff_t offset, u64 inum,
71 unsigned int type)
72{
73 struct get_name_filldir *gnfd =
74 container_of(ctx, struct get_name_filldir, ctx);
75
76 if (inum != gnfd->inum.no_addr)
77 return true;
78
79 memcpy(gnfd->name, name, length);
80 gnfd->name[length] = 0;
81
82 return false;
83}
84
85static int gfs2_get_name(struct dentry *parent, char *name,
86 struct dentry *child)
87{
88 struct inode *dir = d_inode(parent);
89 struct inode *inode = d_inode(child);
90 struct gfs2_glock *gl;
91 struct gfs2_inode *ip;
92 struct get_name_filldir gnfd = {
93 .ctx.actor = get_name_filldir,
94 .name = name
95 };
96 struct gfs2_holder gh;
97 int error;
98 struct file_ra_state f_ra = { .start = 0 };
99
100 if (!dir)
101 return -EINVAL;
102
103 if (!S_ISDIR(dir->i_mode) || !inode)
104 return -EINVAL;
105
106 gl = gfs2_inode_glock(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
113 error = gfs2_glock_nq_init(gl, LM_ST_SHARED, 0, &gh);
114 if (error)
115 return error;
116
117 error = gfs2_dir_read(dir, &gnfd.ctx, &f_ra);
118
119 gfs2_glock_dq_uninit(&gh);
120
121 if (!error && !*name)
122 error = -ENOENT;
123
124 return error;
125}
126
127static struct dentry *gfs2_get_parent(struct dentry *child)
128{
129 return d_obtain_alias(gfs2_lookupi(d_inode(child), &gfs2_qdotdot, 1));
130}
131
132static struct dentry *gfs2_get_dentry(struct super_block *sb,
133 struct gfs2_inum_host *inum)
134{
135 struct gfs2_sbd *sdp = sb->s_fs_info;
136 struct inode *inode;
137
138 if (!inum->no_formal_ino)
139 return ERR_PTR(-ESTALE);
140 inode = gfs2_lookup_by_inum(sdp, inum->no_addr, inum->no_formal_ino,
141 GFS2_BLKST_DINODE);
142 return d_obtain_alias(inode);
143}
144
145static struct dentry *gfs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
146 int fh_len, int fh_type)
147{
148 struct gfs2_inum_host this;
149 __be32 *fh = (__force __be32 *)fid->raw;
150
151 switch (fh_type) {
152 case GFS2_SMALL_FH_SIZE:
153 case GFS2_LARGE_FH_SIZE:
154 case GFS2_OLD_FH_SIZE:
155 if (fh_len < GFS2_SMALL_FH_SIZE)
156 return NULL;
157 this.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
158 this.no_formal_ino |= be32_to_cpu(fh[1]);
159 this.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
160 this.no_addr |= be32_to_cpu(fh[3]);
161 return gfs2_get_dentry(sb, &this);
162 default:
163 return NULL;
164 }
165}
166
167static struct dentry *gfs2_fh_to_parent(struct super_block *sb, struct fid *fid,
168 int fh_len, int fh_type)
169{
170 struct gfs2_inum_host parent;
171 __be32 *fh = (__force __be32 *)fid->raw;
172
173 switch (fh_type) {
174 case GFS2_LARGE_FH_SIZE:
175 case GFS2_OLD_FH_SIZE:
176 if (fh_len < GFS2_LARGE_FH_SIZE)
177 return NULL;
178 parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
179 parent.no_formal_ino |= be32_to_cpu(fh[5]);
180 parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
181 parent.no_addr |= be32_to_cpu(fh[7]);
182 return gfs2_get_dentry(sb, &parent);
183 default:
184 return NULL;
185 }
186}
187
188const struct export_operations gfs2_export_ops = {
189 .encode_fh = gfs2_encode_fh,
190 .fh_to_dentry = gfs2_fh_to_dentry,
191 .fh_to_parent = gfs2_fh_to_parent,
192 .get_name = gfs2_get_name,
193 .get_parent = gfs2_get_parent,
194};
195