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 <net/9p/9p.h>
  36 #include <net/9p/client.h>
  37
  38 #include "v9fs.h"
  39 #include "v9fs_vfs.h"
  40 #include "fid.h"
  41
  42 /**
  43  * struct p9_rdir - readdir accounting
  44  * @mutex: mutex protecting readdir
  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         struct mutex mutex;
  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_dir_readdir - read a directory
  90  * @filp: opened file structure
  91  * @dirent: directory structure ???
  92  * @filldir: function to populate directory structure ???
  93  *
  94  */
  95
  96 static int v9fs_dir_readdir(struct file *filp, void *dirent, filldir_t filldir)
  97 {
  98         int over;
  99         struct p9_wstat st;
 100         int err = 0;
 101         struct p9_fid *fid;
 102         int buflen;
 103         int reclen = 0;
 104         struct p9_rdir *rdir;
 105
 106         P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", filp->f_path.dentry->d_name.name);
 107         fid = filp->private_data;
 108
 109         buflen = fid->clnt->msize - P9_IOHDRSZ;
 110
 111         /* allocate rdir on demand */
 112         if (!fid->rdir) {
 113                 rdir = kmalloc(sizeof(struct p9_rdir) + buflen, GFP_KERNEL);
 114
 115                 if (rdir == NULL) {
 116                         err = -ENOMEM;
 117                         goto exit;
 118                 }
 119                 spin_lock(&filp->f_dentry->d_lock);
 120                 if (!fid->rdir) {
 121                         rdir->buf = (uint8_t *)rdir + sizeof(struct p9_rdir);
 122                         mutex_init(&rdir->mutex);
 123                         rdir->head = rdir->tail = 0;
 124                         fid->rdir = (void *) rdir;
 125                         rdir = NULL;
 126                 }
 127                 spin_unlock(&filp->f_dentry->d_lock);
 128                 kfree(rdir);
 129         }
 130         rdir = (struct p9_rdir *) fid->rdir;
 131
 132         err = mutex_lock_interruptible(&rdir->mutex);
 133         while (err == 0) {
 134                 if (rdir->tail == rdir->head) {
 135                         err = v9fs_file_readn(filp, rdir->buf, NULL,
 136                                                         buflen, filp->f_pos);
 137                         if (err <= 0)
 138                                 goto unlock_and_exit;
 139
 140                         rdir->head = 0;
 141                         rdir->tail = err;
 142                 }
 143                 while (rdir->head < rdir->tail) {
 144                         p9stat_init(&st);
 145                         err = p9stat_read(rdir->buf + rdir->head,
 146                                                 buflen - rdir->head, &st,
 147                                                 fid->clnt->proto_version);
 148                         if (err) {
 149                                 P9_DPRINTK(P9_DEBUG_VFS, "returned %d\n", err);
 150                                 err = -EIO;
 151                                 p9stat_free(&st);
 152                                 goto unlock_and_exit;
 153                         }
 154                         reclen = st.size+2;
 155
 156                         over = filldir(dirent, st.name, strlen(st.name),
 157                             filp->f_pos, v9fs_qid2ino(&st.qid), dt_type(&st));
 158
 159                         p9stat_free(&st);
 160
 161                         if (over) {
 162                                 err = 0;
 163                                 goto unlock_and_exit;
 164                         }
 165                         rdir->head += reclen;
 166                         filp->f_pos += reclen;
 167                 }
 168         }
 169
 170 unlock_and_exit:
 171         mutex_unlock(&rdir->mutex);
 172 exit:
 173         return err;
 174 }
 175
 176
 177 /**
 178  * v9fs_dir_release - close a directory
 179  * @inode: inode of the directory
 180  * @filp: file pointer to a directory
 181  *
 182  */
 183
 184 int v9fs_dir_release(struct inode *inode, struct file *filp)
 185 {
 186         struct p9_fid *fid;
 187
 188         fid = filp->private_data;
 189         P9_DPRINTK(P9_DEBUG_VFS,
 190                         "inode: %p filp: %p fid: %d\n", inode, filp, fid->fid);
 191         filemap_write_and_wait(inode->i_mapping);
 192         p9_client_clunk(fid);
 193         return 0;
 194 }
 195
 196 const struct file_operations v9fs_dir_operations = {
 197         .read = generic_read_dir,
 198         .llseek = generic_file_llseek,
 199         .readdir = v9fs_dir_readdir,
 200         .open = v9fs_file_open,
 201         .release = v9fs_dir_release,
 202 };