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 <net/9p/9p.h> 37 #include <net/9p/client.h> 38 39 #include "v9fs.h" 40 #include "v9fs_vfs.h" 41 #include "fid.h" 42 43 /** 44 * struct p9_rdir - readdir accounting 45 * @mutex: mutex protecting readdir 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; 119 120 p9_debug(P9_DEBUG_VFS, "name %s\n", file->f_path.dentry->d_name.name); 121 fid = file->private_data; 122 123 buflen = fid->clnt->msize - P9_IOHDRSZ; 124 125 rdir = v9fs_alloc_rdir_buf(file, buflen); 126 if (!rdir) 127 return -ENOMEM; 128 129 while (1) { 130 if (rdir->tail == rdir->head) { 131 err = v9fs_file_readn(file, rdir->buf, NULL, 132 buflen, ctx->pos); 133 if (err <= 0) 134 return err; 135 136 rdir->head = 0; 137 rdir->tail = err; 138 } 139 while (rdir->head < rdir->tail) { 140 p9stat_init(&st); 141 err = p9stat_read(fid->clnt, rdir->buf + rdir->head, 142 rdir->tail - rdir->head, &st); 143 if (err) { 144 p9_debug(P9_DEBUG_VFS, "returned %d\n", err); 145 p9stat_free(&st); 146 return -EIO; 147 } 148 reclen = st.size+2; 149 150 over = !dir_emit(ctx, st.name, strlen(st.name), 151 v9fs_qid2ino(&st.qid), dt_type(&st)); 152 p9stat_free(&st); 153 if (over) 154 return 0; 155 156 rdir->head += reclen; 157 ctx->pos += reclen; 158 } 159 } 160 } 161 162 /** 163 * v9fs_dir_readdir_dotl - iterate through a directory 164 * @file: opened file structure 165 * @ctx: actor we feed the entries to 166 * 167 */ 168 static int v9fs_dir_readdir_dotl(struct file *file, struct dir_context *ctx) 169 { 170 int err = 0; 171 struct p9_fid *fid; 172 int buflen; 173 struct p9_rdir *rdir; 174 struct p9_dirent curdirent; 175 176 p9_debug(P9_DEBUG_VFS, "name %s\n", file->f_path.dentry->d_name.name); 177 fid = file->private_data; 178 179 buflen = fid->clnt->msize - P9_READDIRHDRSZ; 180 181 rdir = v9fs_alloc_rdir_buf(file, buflen); 182 if (!rdir) 183 return -ENOMEM; 184 185 while (1) { 186 if (rdir->tail == rdir->head) { 187 err = p9_client_readdir(fid, rdir->buf, buflen, 188 ctx->pos); 189 if (err <= 0) 190 return err; 191 192 rdir->head = 0; 193 rdir->tail = err; 194 } 195 196 while (rdir->head < rdir->tail) { 197 198 err = p9dirent_read(fid->clnt, rdir->buf + rdir->head, 199 rdir->tail - rdir->head, 200 &curdirent); 201 if (err < 0) { 202 p9_debug(P9_DEBUG_VFS, "returned %d\n", err); 203 return -EIO; 204 } 205 206 if (!dir_emit(ctx, curdirent.d_name, 207 strlen(curdirent.d_name), 208 v9fs_qid2ino(&curdirent.qid), 209 curdirent.d_type)) 210 return 0; 211 212 ctx->pos = curdirent.d_off; 213 rdir->head += err; 214 } 215 } 216 } 217 218 219 /** 220 * v9fs_dir_release - close a directory 221 * @inode: inode of the directory 222 * @filp: file pointer to a directory 223 * 224 */ 225 226 int v9fs_dir_release(struct inode *inode, struct file *filp) 227 { 228 struct p9_fid *fid; 229 230 fid = filp->private_data; 231 p9_debug(P9_DEBUG_VFS, "inode: %p filp: %p fid: %d\n", 232 inode, filp, fid ? fid->fid : -1); 233 if (fid) 234 p9_client_clunk(fid); 235 return 0; 236 } 237 238 const struct file_operations v9fs_dir_operations = { 239 .read = generic_read_dir, 240 .llseek = generic_file_llseek, 241 .iterate = v9fs_dir_readdir, 242 .open = v9fs_file_open, 243 .release = v9fs_dir_release, 244 }; 245 246 const struct file_operations v9fs_dir_operations_dotl = { 247 .read = generic_read_dir, 248 .llseek = generic_file_llseek, 249 .iterate = v9fs_dir_readdir_dotl, 250 .open = v9fs_file_open, 251 .release = v9fs_dir_release, 252 .fsync = v9fs_file_fsync_dotl, 253 }; 254