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  * @head: start offset of current dirread buffer
  46  * @tail: end offset of current dirread buffer
  47  * @buf: dirread buffer
  48  *
  49  * private structure for keeping track of readdir
  50  * allocated on demand
  51  */
  52
  53 struct p9_rdir {
  54         int head;
  55         int tail;
  56         uint8_t buf[];
  57 };
  58
  59 /**
  60  * dt_type - return file type
  61  * @mistat: mistat structure
  62  *
  63  */
  64
  65 static inline int dt_type(struct p9_wstat *mistat)
  66 {
  67         unsigned long perm = mistat->mode;
  68         int rettype = DT_REG;
  69
  70         if (perm & P9_DMDIR)
  71                 rettype = DT_DIR;
  72         if (perm & P9_DMSYMLINK)
  73                 rettype = DT_LNK;
  74
  75         return rettype;
  76 }
  77
  78 static void p9stat_init(struct p9_wstat *stbuf)
  79 {
  80         stbuf->name  = NULL;
  81         stbuf->uid   = NULL;
  82         stbuf->gid   = NULL;
  83         stbuf->muid  = NULL;
  84         stbuf->extension = NULL;
  85 }
  86
  87 /**
  88  * v9fs_alloc_rdir_buf - Allocate buffer used for read and readdir
  89  * @filp: opened file structure
  90  * @buflen: Length in bytes of buffer to allocate
  91  *
  92  */
  93
  94 static struct p9_rdir *v9fs_alloc_rdir_buf(struct file *filp, int buflen)
  95 {
  96         struct p9_fid *fid = filp->private_data;
  97         if (!fid->rdir)
  98                 fid->rdir = kzalloc(sizeof(struct p9_rdir) + buflen, GFP_KERNEL);
  99         return fid->rdir;
 100 }
 101
 102 /**
 103  * v9fs_dir_readdir - iterate through a directory
 104  * @file: opened file structure
 105  * @ctx: actor we feed the entries to
 106  *
 107  */
 108
 109 static int v9fs_dir_readdir(struct file *file, struct dir_context *ctx)
 110 {
 111         bool over;
 112         struct p9_wstat st;
 113         int err = 0;
 114         struct p9_fid *fid;
 115         int buflen;
 116         int reclen = 0;
 117         struct p9_rdir *rdir;
 118
 119         p9_debug(P9_DEBUG_VFS, "name %s\n", file->f_path.dentry->d_name.name);
 120         fid = file->private_data;
 121
 122         buflen = fid->clnt->msize - P9_IOHDRSZ;
 123
 124         rdir = v9fs_alloc_rdir_buf(file, buflen);
 125         if (!rdir)
 126                 return -ENOMEM;
 127
 128         while (1) {
 129                 if (rdir->tail == rdir->head) {
 130                         err = v9fs_file_readn(file, rdir->buf, NULL,
 131                                                         buflen, ctx->pos);
 132                         if (err <= 0)
 133                                 return err;
 134
 135                         rdir->head = 0;
 136                         rdir->tail = err;
 137                 }
 138                 while (rdir->head < rdir->tail) {
 139                         p9stat_init(&st);
 140                         err = p9stat_read(fid->clnt, rdir->buf + rdir->head,
 141                                           rdir->tail - rdir->head, &st);
 142                         if (err) {
 143                                 p9_debug(P9_DEBUG_VFS, "returned %d\n", err);
 144                                 p9stat_free(&st);
 145                                 return -EIO;
 146                         }
 147                         reclen = st.size+2;
 148
 149                         over = !dir_emit(ctx, st.name, strlen(st.name),
 150                                          v9fs_qid2ino(&st.qid), dt_type(&st));
 151                         p9stat_free(&st);
 152                         if (over)
 153                                 return 0;
 154
 155                         rdir->head += reclen;
 156                         ctx->pos += reclen;
 157                 }
 158         }
 159 }
 160
 161 /**
 162  * v9fs_dir_readdir_dotl - iterate through a directory
 163  * @file: opened file structure
 164  * @ctx: actor we feed the entries to
 165  *
 166  */
 167 static int v9fs_dir_readdir_dotl(struct file *file, struct dir_context *ctx)
 168 {
 169         int err = 0;
 170         struct p9_fid *fid;
 171         int buflen;
 172         struct p9_rdir *rdir;
 173         struct p9_dirent curdirent;
 174
 175         p9_debug(P9_DEBUG_VFS, "name %s\n", file->f_path.dentry->d_name.name);
 176         fid = file->private_data;
 177
 178         buflen = fid->clnt->msize - P9_READDIRHDRSZ;
 179
 180         rdir = v9fs_alloc_rdir_buf(file, buflen);
 181         if (!rdir)
 182                 return -ENOMEM;
 183
 184         while (1) {
 185                 if (rdir->tail == rdir->head) {
 186                         err = p9_client_readdir(fid, rdir->buf, buflen,
 187                                                 ctx->pos);
 188                         if (err <= 0)
 189                                 return err;
 190
 191                         rdir->head = 0;
 192                         rdir->tail = err;
 193                 }
 194
 195                 while (rdir->head < rdir->tail) {
 196
 197                         err = p9dirent_read(fid->clnt, rdir->buf + rdir->head,
 198                                             rdir->tail - rdir->head,
 199                                             &curdirent);
 200                         if (err < 0) {
 201                                 p9_debug(P9_DEBUG_VFS, "returned %d\n", err);
 202                                 return -EIO;
 203                         }
 204
 205                         if (!dir_emit(ctx, curdirent.d_name,
 206                                       strlen(curdirent.d_name),
 207                                       v9fs_qid2ino(&curdirent.qid),
 208                                       curdirent.d_type))
 209                                 return 0;
 210
 211                         ctx->pos = curdirent.d_off;
 212                         rdir->head += err;
 213                 }
 214         }
 215 }
 216
 217
 218 /**
 219  * v9fs_dir_release - close a directory
 220  * @inode: inode of the directory
 221  * @filp: file pointer to a directory
 222  *
 223  */
 224
 225 int v9fs_dir_release(struct inode *inode, struct file *filp)
 226 {
 227         struct p9_fid *fid;
 228
 229         fid = filp->private_data;
 230         p9_debug(P9_DEBUG_VFS, "inode: %p filp: %p fid: %d\n",
 231                  inode, filp, fid ? fid->fid : -1);
 232         if (fid)
 233                 p9_client_clunk(fid);
 234         return 0;
 235 }
 236
 237 const struct file_operations v9fs_dir_operations = {
 238         .read = generic_read_dir,
 239         .llseek = generic_file_llseek,
 240         .iterate = v9fs_dir_readdir,
 241         .open = v9fs_file_open,
 242         .release = v9fs_dir_release,
 243 };
 244
 245 const struct file_operations v9fs_dir_operations_dotl = {
 246         .read = generic_read_dir,
 247         .llseek = generic_file_llseek,
 248         .iterate = v9fs_dir_readdir_dotl,
 249         .open = v9fs_file_open,
 250         .release = v9fs_dir_release,
 251         .fsync = v9fs_file_fsync_dotl,
 252 };