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 - 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 };