| 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 | }; |