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_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 } 126 127 static struct dentry *gfs2_get_parent(struct dentry *child) 128 { 129 return d_obtain_alias(gfs2_lookupi(d_inode(child), &gfs2_qdotdot, 1)); 130 } 131 132 static 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 } 144 145 static 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 } 166 167 static 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 } 187 188 const 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 }; 195 196