1 /* 2 * linux/fs/9p/vfs_dir.c 3 * 4 * This file contains vfs directory ops for the 9P2000 protocol. 5 * 6 * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com> 7 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 11 * as published by the Free Software Foundation. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to: 20 * Free Software Foundation 21 * 51 Franklin Street, Fifth Floor 22 * Boston, MA 02111-1301 USA 23 * 24 */ 25 26 #include <linux/module.h> 27 #include <linux/errno.h> 28 #include <linux/fs.h> 29 #include <linux/file.h> 30 #include <linux/stat.h> 31 #include <linux/string.h> 32 #include <linux/sched.h> 33 #include <linux/inet.h> 34 #include <linux/idr.h> 35 #include <linux/slab.h> 36 #include <linux/uio.h> 37 #include <net/9p/9p.h> 38 #include <net/9p/client.h> 39 40 #include "v9fs.h" 41 #include "v9fs_vfs.h" 42 #include "fid.h" 43 44 /** 45 * struct p9_rdir - readdir accounting 46 * @head: start offset of current dirread buffer 47 * @tail: end offset of current dirread buffer 48 * @buf: dirread buffer 49 * 50 * private structure for keeping track of readdir 51 * allocated on demand 52 */ 53 54 struct p9_rdir { 55 int head; 56 int tail; 57 uint8_t buf[]; 58 }; 59 60 /** 61 * dt_type - return file type 62 * @mistat: mistat structure 63 * 64 */ 65 66 static inline int dt_type(struct p9_wstat *mistat) 67 { 68 unsigned long perm = mistat->mode; 69 int rettype = DT_REG; 70 71 if (perm & P9_DMDIR) 72 rettype = DT_DIR; 73 if (perm & P9_DMSYMLINK) 74 rettype = DT_LNK; 75 76 return rettype; 77 } 78 79 static void p9stat_init(struct p9_wstat *stbuf) 80 { 81 stbuf->name = NULL; 82 stbuf->uid = NULL; 83 stbuf->gid = NULL; 84 stbuf->muid = NULL; 85 stbuf->extension = NULL; 86 } 87 88 /** 89 * v9fs_alloc_rdir_buf - Allocate buffer used for read and readdir 90 * @filp: opened file structure 91 * @buflen: Length in bytes of buffer to allocate 92 * 93 */ 94 95 static struct p9_rdir *v9fs_alloc_rdir_buf(struct file *filp, int buflen) 96 { 97 struct p9_fid *fid = filp->private_data; 98 if (!fid->rdir) 99 fid->rdir = kzalloc(sizeof(struct p9_rdir) + buflen, GFP_KERNEL); 100 return fid->rdir; 101 } 102 103 /** 104 * v9fs_dir_readdir - iterate through a directory 105 * @file: opened file structure 106 * @ctx: actor we feed the entries to 107 * 108 */ 109 110 static int v9fs_dir_readdir(struct file *file, struct dir_context *ctx) 111 { 112 bool over; 113 struct p9_wstat st; 114 int err = 0; 115 struct p9_fid *fid; 116 int buflen; 117 int reclen = 0; 118 struct p9_rdir *rdir; 119 struct kvec kvec; 120 121 p9_debug(P9_DEBUG_VFS, "name %pD\n", file); 122 fid = file->private_data; 123 124 buflen = fid->clnt->msize - P9_IOHDRSZ; 125 126 rdir = v9fs_alloc_rdir_buf(file, buflen); 127 if (!rdir) 128 return -ENOMEM; 129 kvec.iov_base = rdir->buf; 130 kvec.iov_len = buflen; 131 132 while (1) { 133 if (rdir->tail == rdir->head) { 134 struct iov_iter to; 135 int n; 136 iov_iter_kvec(&to, READ | ITER_KVEC, &kvec, 1, buflen); 137 n = p9_client_read(file->private_data, ctx->pos, &to, 138 &err); 139 if (err) 140 return err; 141 142 rdir->head = 0; 143 rdir->tail = n; 144 } 145 while (rdir->head < rdir->tail) { 146 p9stat_init(&st); 147 err = p9stat_read(fid->clnt, rdir->buf + rdir->head, 148 rdir->tail - rdir->head, &st); 149 if (err) { 150 p9_debug(P9_DEBUG_VFS, "returned %d\n", err); 151 p9stat_free(&st); 152 return -EIO; 153 } 154 reclen = st.size+2; 155 156 over = !dir_emit(ctx, st.name, strlen(st.name), 157 v9fs_qid2ino(&st.qid), dt_type(&st)); 158 p9stat_free(&st); 159 if (over) 160 return 0; 161 162 rdir->head += reclen; 163 ctx->pos += reclen; 164 } 165 } 166 } 167 168 /** 169 * v9fs_dir_readdir_dotl - iterate through a directory 170 * @file: opened file structure 171 * @ctx: actor we feed the entries to 172 * 173 */ 174 static int v9fs_dir_readdir_dotl(struct file *file, struct dir_context *ctx) 175 { 176 int err = 0; 177 struct p9_fid *fid; 178 int buflen; 179 struct p9_rdir *rdir; 180 struct p9_dirent curdirent; 181 182 p9_debug(P9_DEBUG_VFS, "name %pD\n", file); 183 fid = file->private_data; 184 185 buflen = fid->clnt->msize - P9_READDIRHDRSZ; 186 187 rdir = v9fs_alloc_rdir_buf(file, buflen); 188 if (!rdir) 189 return -ENOMEM; 190 191 while (1) { 192 if (rdir->tail == rdir->head) { 193 err = p9_client_readdir(fid, rdir->buf, buflen, 194 ctx->pos); 195 if (err <= 0) 196 return err; 197 198 rdir->head = 0; 199 rdir->tail = err; 200 } 201 202 while (rdir->head < rdir->tail) { 203 204 err = p9dirent_read(fid->clnt, rdir->buf + rdir->head, 205 rdir->tail - rdir->head, 206 &curdirent); 207 if (err < 0) { 208 p9_debug(P9_DEBUG_VFS, "returned %d\n", err); 209 return -EIO; 210 } 211 212 if (!dir_emit(ctx, curdirent.d_name, 213 strlen(curdirent.d_name), 214 v9fs_qid2ino(&curdirent.qid), 215 curdirent.d_type)) 216 return 0; 217 218 ctx->pos = curdirent.d_off; 219 rdir->head += err; 220 } 221 } 222 } 223 224 225 /** 226 * v9fs_dir_release - close a directory 227 * @inode: inode of the directory 228 * @filp: file pointer to a directory 229 * 230 */ 231 232 int v9fs_dir_release(struct inode *inode, struct file *filp) 233 { 234 struct p9_fid *fid; 235 236 fid = filp->private_data; 237 p9_debug(P9_DEBUG_VFS, "inode: %p filp: %p fid: %d\n", 238 inode, filp, fid ? fid->fid : -1); 239 if (fid) 240 p9_client_clunk(fid); 241 return 0; 242 } 243 244 const struct file_operations v9fs_dir_operations = { 245 .read = generic_read_dir, 246 .llseek = generic_file_llseek, 247 .iterate = v9fs_dir_readdir, 248 .open = v9fs_file_open, 249 .release = v9fs_dir_release, 250 }; 251 252 const struct file_operations v9fs_dir_operations_dotl = { 253 .read = generic_read_dir, 254 .llseek = generic_file_llseek, 255 .iterate = v9fs_dir_readdir_dotl, 256 .open = v9fs_file_open, 257 .release = v9fs_dir_release, 258 .fsync = v9fs_file_fsync_dotl, 259 }; 260