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
28 static 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
63 struct get_name_filldir {
64 struct dir_context ctx;
65 struct gfs2_inum_host inum;
66 char *name;
67 };
68
69 static 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
85 static 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_inode *dip, *ip;
91 struct get_name_filldir gnfd = {
92 .ctx.actor = get_name_filldir,
93 .name = name
94 };
95 struct gfs2_holder gh;
96 int error;
97 struct file_ra_state f_ra = { .start = 0 };
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
112 error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
113 if (error)
114 return error;
115
116 error = gfs2_dir_read(dir, &gnfd.ctx, &f_ra);
117
118 gfs2_glock_dq_uninit(&gh);
119
120 if (!error && !*name)
121 error = -ENOENT;
122
123 return error;
124 }
125
126 static struct dentry *gfs2_get_parent(struct dentry *child)
127 {
128 return d_obtain_alias(gfs2_lookupi(d_inode(child), &gfs2_qdotdot, 1));
129 }
130
131 static struct dentry *gfs2_get_dentry(struct super_block *sb,
132 struct gfs2_inum_host *inum)
133 {
134 struct gfs2_sbd *sdp = sb->s_fs_info;
135 struct inode *inode;
136
137 if (!inum->no_formal_ino)
138 return ERR_PTR(-ESTALE);
139 inode = gfs2_lookup_by_inum(sdp, inum->no_addr, inum->no_formal_ino,
140 GFS2_BLKST_DINODE);
141 return d_obtain_alias(inode);
142 }
143
144 static struct dentry *gfs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
145 int fh_len, int fh_type)
146 {
147 struct gfs2_inum_host this;
148 __be32 *fh = (__force __be32 *)fid->raw;
149
150 switch (fh_type) {
151 case GFS2_SMALL_FH_SIZE:
152 case GFS2_LARGE_FH_SIZE:
153 case GFS2_OLD_FH_SIZE:
154 if (fh_len < GFS2_SMALL_FH_SIZE)
155 return NULL;
156 this.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
157 this.no_formal_ino |= be32_to_cpu(fh[1]);
158 this.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
159 this.no_addr |= be32_to_cpu(fh[3]);
160 return gfs2_get_dentry(sb, &this);
161 default:
162 return NULL;
163 }
164 }
165
166 static struct dentry *gfs2_fh_to_parent(struct super_block *sb, struct fid *fid,
167 int fh_len, int fh_type)
168 {
169 struct gfs2_inum_host parent;
170 __be32 *fh = (__force __be32 *)fid->raw;
171
172 switch (fh_type) {
173 case GFS2_LARGE_FH_SIZE:
174 case GFS2_OLD_FH_SIZE:
175 if (fh_len < GFS2_LARGE_FH_SIZE)
176 return NULL;
177 parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
178 parent.no_formal_ino |= be32_to_cpu(fh[5]);
179 parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
180 parent.no_addr |= be32_to_cpu(fh[7]);
181 return gfs2_get_dentry(sb, &parent);
182 default:
183 return NULL;
184 }
185 }
186
187 const struct export_operations gfs2_export_ops = {
188 .encode_fh = gfs2_encode_fh,
189 .fh_to_dentry = gfs2_fh_to_dentry,
190 .fh_to_parent = gfs2_fh_to_parent,
191 .get_name = gfs2_get_name,
192 .get_parent = gfs2_get_parent,
193 .flags = EXPORT_OP_ASYNC_LOCK,
194 };
195
196
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