fs/9p/vfs_dir.c

   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 - read a directory
 105  * @filp: opened file structure
 106  * @dirent: directory structure ???
 107  * @filldir: function to populate directory structure ???
 108  *
 109  */
 110
 111 static int v9fs_dir_readdir(struct file *filp, void *dirent, filldir_t filldir)
 112 {
 113         int over;
 114         struct p9_wstat st;
 115         int err = 0;
 116         struct p9_fid *fid;
 117         int buflen;
 118         int reclen = 0;
 119         struct p9_rdir *rdir;
 120
 121         p9_debug(P9_DEBUG_VFS, "name %s\n", filp->f_path.dentry->d_name.name);
 122         fid = filp->private_data;
 123
 124         buflen = fid->clnt->msize - P9_IOHDRSZ;
 125
 126         rdir = v9fs_alloc_rdir_buf(filp, buflen);
 127         if (!rdir)
 128                 return -ENOMEM;
 129
 130         while (1) {
 131                 if (rdir->tail == rdir->head) {
 132                         err = v9fs_file_readn(filp, rdir->buf, NULL,
 133                                                         buflen, filp->f_pos);
 134                         if (err <= 0)
 135                                 return err;
 136
 137                         rdir->head = 0;
 138                         rdir->tail = err;
 139                 }
 140                 while (rdir->head < rdir->tail) {
 141                         p9stat_init(&st);
 142                         err = p9stat_read(fid->clnt, rdir->buf + rdir->head,
 143                                           rdir->tail - rdir->head, &st);
 144                         if (err) {
 145                                 p9_debug(P9_DEBUG_VFS, "returned %d\n", err);
 146                                 p9stat_free(&st);
 147                                 return -EIO;
 148                         }
 149                         reclen = st.size+2;
 150
 151                         over = filldir(dirent, st.name, strlen(st.name),
 152                             filp->f_pos, v9fs_qid2ino(&st.qid), dt_type(&st));
 153
 154                         p9stat_free(&st);
 155
 156                         if (over)
 157                                 return 0;
 158
 159                         rdir->head += reclen;
 160                         filp->f_pos += reclen;
 161                 }
 162         }
 163 }
 164
 165 /**
 166  * v9fs_dir_readdir_dotl - read a directory
 167  * @filp: opened file structure
 168  * @dirent: buffer to fill dirent structures
 169  * @filldir: function to populate dirent structures
 170  *
 171  */
 172 static int v9fs_dir_readdir_dotl(struct file *filp, void *dirent,
 173                                                 filldir_t filldir)
 174 {
 175         int over;
 176         int err = 0;
 177         struct p9_fid *fid;
 178         int buflen;
 179         struct p9_rdir *rdir;
 180         struct p9_dirent curdirent;
 181         u64 oldoffset = 0;
 182
 183         p9_debug(P9_DEBUG_VFS, "name %s\n", filp->f_path.dentry->d_name.name);
 184         fid = filp->private_data;
 185
 186         buflen = fid->clnt->msize - P9_READDIRHDRSZ;
 187
 188         rdir = v9fs_alloc_rdir_buf(filp, buflen);
 189         if (!rdir)
 190                 return -ENOMEM;
 191
 192         while (1) {
 193                 if (rdir->tail == rdir->head) {
 194                         err = p9_client_readdir(fid, rdir->buf, buflen,
 195                                                 filp->f_pos);
 196                         if (err <= 0)
 197                                 return err;
 198
 199                         rdir->head = 0;
 200                         rdir->tail = err;
 201                 }
 202
 203                 while (rdir->head < rdir->tail) {
 204
 205                         err = p9dirent_read(fid->clnt, rdir->buf + rdir->head,
 206                                             rdir->tail - rdir->head,
 207                                             &curdirent);
 208                         if (err < 0) {
 209                                 p9_debug(P9_DEBUG_VFS, "returned %d\n", err);
 210                                 return -EIO;
 211                         }
 212
 213                         /* d_off in dirent structure tracks the offset into
 214                          * the next dirent in the dir. However, filldir()
 215                          * expects offset into the current dirent. Hence
 216                          * while calling filldir send the offset from the
 217                          * previous dirent structure.
 218                          */
 219                         over = filldir(dirent, curdirent.d_name,
 220                                         strlen(curdirent.d_name),
 221                                         oldoffset, v9fs_qid2ino(&curdirent.qid),
 222                                         curdirent.d_type);
 223                         oldoffset = curdirent.d_off;
 224
 225                         if (over)
 226                                 return 0;
 227
 228                         filp->f_pos = curdirent.d_off;
 229                         rdir->head += err;
 230                 }
 231         }
 232 }
 233
 234
 235 /**
 236  * v9fs_dir_release - close a directory
 237  * @inode: inode of the directory
 238  * @filp: file pointer to a directory
 239  *
 240  */
 241
 242 int v9fs_dir_release(struct inode *inode, struct file *filp)
 243 {
 244         struct p9_fid *fid;
 245
 246         fid = filp->private_data;
 247         p9_debug(P9_DEBUG_VFS, "inode: %p filp: %p fid: %d\n",
 248                  inode, filp, fid ? fid->fid : -1);
 249         if (fid)
 250                 p9_client_clunk(fid);
 251         return 0;
 252 }
 253
 254 const struct file_operations v9fs_dir_operations = {
 255         .read = generic_read_dir,
 256         .llseek = generic_file_llseek,
 257         .readdir = v9fs_dir_readdir,
 258         .open = v9fs_file_open,
 259         .release = v9fs_dir_release,
 260 };
 261
 262 const struct file_operations v9fs_dir_operations_dotl = {
 263         .read = generic_read_dir,
 264         .llseek = generic_file_llseek,
 265         .readdir = v9fs_dir_readdir_dotl,
 266         .open = v9fs_file_open,
 267         .release = v9fs_dir_release,
 268         .fsync = v9fs_file_fsync_dotl,
 269 };