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         struct mutex mutex;
  56         int head;
  57         int tail;
  58         uint8_t *buf;
  59 };
  60
  61 /**
  62  * dt_type - return file type
  63  * @mistat: mistat structure
  64  *
  65  */
  66
  67 static inline int dt_type(struct p9_wstat *mistat)
  68 {
  69         unsigned long perm = mistat->mode;
  70         int rettype = DT_REG;
  71
  72         if (perm & P9_DMDIR)
  73                 rettype = DT_DIR;
  74         if (perm & P9_DMSYMLINK)
  75                 rettype = DT_LNK;
  76
  77         return rettype;
  78 }
  79
  80 static void p9stat_init(struct p9_wstat *stbuf)
  81 {
  82         stbuf->name  = NULL;
  83         stbuf->uid   = NULL;
  84         stbuf->gid   = NULL;
  85         stbuf->muid  = NULL;
  86         stbuf->extension = NULL;
  87 }
  88
  89 /**
  90  * v9fs_dir_readdir - read a directory
  91  * @filp: opened file structure
  92  * @dirent: directory structure ???
  93  * @filldir: function to populate directory structure ???
  94  *
  95  */
  96
  97 static int v9fs_dir_readdir(struct file *filp, void *dirent, filldir_t filldir)
  98 {
  99         int over;
 100         struct p9_wstat st;
 101         int err = 0;
 102         struct p9_fid *fid;
 103         int buflen;
 104         int reclen = 0;
 105         struct p9_rdir *rdir;
 106
 107         P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", filp->f_path.dentry->d_name.name);
 108         fid = filp->private_data;
 109
 110         buflen = fid->clnt->msize - P9_IOHDRSZ;
 111
 112         /* allocate rdir on demand */
 113         if (!fid->rdir) {
 114                 rdir = kmalloc(sizeof(struct p9_rdir) + buflen, GFP_KERNEL);
 115
 116                 if (rdir == NULL) {
 117                         err = -ENOMEM;
 118                         goto exit;
 119                 }
 120                 spin_lock(&filp->f_dentry->d_lock);
 121                 if (!fid->rdir) {
 122                         rdir->buf = (uint8_t *)rdir + sizeof(struct p9_rdir);
 123                         mutex_init(&rdir->mutex);
 124                         rdir->head = rdir->tail = 0;
 125                         fid->rdir = (void *) rdir;
 126                         rdir = NULL;
 127                 }
 128                 spin_unlock(&filp->f_dentry->d_lock);
 129                 kfree(rdir);
 130         }
 131         rdir = (struct p9_rdir *) fid->rdir;
 132
 133         err = mutex_lock_interruptible(&rdir->mutex);
 134         if (err)
 135                 return err;
 136         while (err == 0) {
 137                 if (rdir->tail == rdir->head) {
 138                         err = v9fs_file_readn(filp, rdir->buf, NULL,
 139                                                         buflen, filp->f_pos);
 140                         if (err <= 0)
 141                                 goto unlock_and_exit;
 142
 143                         rdir->head = 0;
 144                         rdir->tail = err;
 145                 }
 146                 while (rdir->head < rdir->tail) {
 147                         p9stat_init(&st);
 148                         err = p9stat_read(rdir->buf + rdir->head,
 149                                                 buflen - rdir->head, &st,
 150                                                 fid->clnt->proto_version);
 151                         if (err) {
 152                                 P9_DPRINTK(P9_DEBUG_VFS, "returned %d\n", err);
 153                                 err = -EIO;
 154                                 p9stat_free(&st);
 155                                 goto unlock_and_exit;
 156                         }
 157                         reclen = st.size+2;
 158
 159                         over = filldir(dirent, st.name, strlen(st.name),
 160                             filp->f_pos, v9fs_qid2ino(&st.qid), dt_type(&st));
 161
 162                         p9stat_free(&st);
 163
 164                         if (over) {
 165                                 err = 0;
 166                                 goto unlock_and_exit;
 167                         }
 168                         rdir->head += reclen;
 169                         filp->f_pos += reclen;
 170                 }
 171         }
 172
 173 unlock_and_exit:
 174         mutex_unlock(&rdir->mutex);
 175 exit:
 176         return err;
 177 }
 178
 179
 180 /**
 181  * v9fs_dir_release - close a directory
 182  * @inode: inode of the directory
 183  * @filp: file pointer to a directory
 184  *
 185  */
 186
 187 int v9fs_dir_release(struct inode *inode, struct file *filp)
 188 {
 189         struct p9_fid *fid;
 190
 191         fid = filp->private_data;
 192         P9_DPRINTK(P9_DEBUG_VFS,
 193                         "inode: %p filp: %p fid: %d\n", inode, filp, fid->fid);
 194         filemap_write_and_wait(inode->i_mapping);
 195         p9_client_clunk(fid);
 196         return 0;
 197 }
 198
 199 const struct file_operations v9fs_dir_operations = {
 200         .read = generic_read_dir,
 201         .llseek = generic_file_llseek,
 202         .readdir = v9fs_dir_readdir,
 203         .open = v9fs_file_open,
 204         .release = v9fs_dir_release,
 205 };
 206
 207 const struct file_operations v9fs_dir_operations_dotl = {
 208         .read = generic_read_dir,
 209         .llseek = generic_file_llseek,
 210         .readdir = v9fs_dir_readdir,
 211         .open = v9fs_file_open,
 212         .release = v9fs_dir_release,
 213 };