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 /**
  80  * v9fs_dir_readdir - read a directory
  81  * @filp: opened file structure
  82  * @dirent: directory structure ???
  83  * @filldir: function to populate directory structure ???
  84  *
  85  */
  86
  87 static int v9fs_dir_readdir(struct file *filp, void *dirent, filldir_t filldir)
  88 {
  89         int over;
  90         struct p9_wstat st;
  91         int err = 0;
  92         struct p9_fid *fid;
  93         int buflen;
  94         int reclen = 0;
  95         struct p9_rdir *rdir;
  96
  97         P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", filp->f_path.dentry->d_name.name);
  98         fid = filp->private_data;
  99
 100         buflen = fid->clnt->msize - P9_IOHDRSZ;
 101
 102         /* allocate rdir on demand */
 103         if (!fid->rdir) {
 104                 rdir = kmalloc(sizeof(struct p9_rdir) + buflen, GFP_KERNEL);
 105
 106                 if (rdir == NULL) {
 107                         err = -ENOMEM;
 108                         goto exit;
 109                 }
 110                 spin_lock(&filp->f_dentry->d_lock);
 111                 if (!fid->rdir) {
 112                         rdir->buf = (uint8_t *)rdir + sizeof(struct p9_rdir);
 113                         mutex_init(&rdir->mutex);
 114                         rdir->head = rdir->tail = 0;
 115                         fid->rdir = (void *) rdir;
 116                         rdir = NULL;
 117                 }
 118                 spin_unlock(&filp->f_dentry->d_lock);
 119                 kfree(rdir);
 120         }
 121         rdir = (struct p9_rdir *) fid->rdir;
 122
 123         err = mutex_lock_interruptible(&rdir->mutex);
 124         while (err == 0) {
 125                 if (rdir->tail == rdir->head) {
 126                         err = v9fs_file_readn(filp, rdir->buf, NULL,
 127                                                         buflen, filp->f_pos);
 128                         if (err <= 0)
 129                                 goto unlock_and_exit;
 130
 131                         rdir->head = 0;
 132                         rdir->tail = err;
 133                 }
 134
 135                 while (rdir->head < rdir->tail) {
 136                         err = p9stat_read(rdir->buf + rdir->head,
 137                                                 buflen - rdir->head, &st,
 138                                                 fid->clnt->dotu);
 139                         if (err) {
 140                                 P9_DPRINTK(P9_DEBUG_VFS, "returned %d\n", err);
 141                                 err = -EIO;
 142                                 p9stat_free(&st);
 143                                 goto unlock_and_exit;
 144                         }
 145                         reclen = st.size+2;
 146
 147                         over = filldir(dirent, st.name, strlen(st.name),
 148                             filp->f_pos, v9fs_qid2ino(&st.qid), dt_type(&st));
 149
 150                         p9stat_free(&st);
 151
 152                         if (over) {
 153                                 err = 0;
 154                                 goto unlock_and_exit;
 155                         }
 156                         rdir->head += reclen;
 157                         filp->f_pos += reclen;
 158                 }
 159         }
 160
 161 unlock_and_exit:
 162         mutex_unlock(&rdir->mutex);
 163 exit:
 164         return err;
 165 }
 166
 167
 168 /**
 169  * v9fs_dir_release - close a directory
 170  * @inode: inode of the directory
 171  * @filp: file pointer to a directory
 172  *
 173  */
 174
 175 int v9fs_dir_release(struct inode *inode, struct file *filp)
 176 {
 177         struct p9_fid *fid;
 178
 179         fid = filp->private_data;
 180         P9_DPRINTK(P9_DEBUG_VFS,
 181                         "inode: %p filp: %p fid: %d\n", inode, filp, fid->fid);
 182         filemap_write_and_wait(inode->i_mapping);
 183         p9_client_clunk(fid);
 184         return 0;
 185 }
 186
 187 const struct file_operations v9fs_dir_operations = {
 188         .read = generic_read_dir,
 189         .llseek = generic_file_llseek,
 190         .readdir = v9fs_dir_readdir,
 191         .open = v9fs_file_open,
 192         .release = v9fs_dir_release,
 193 };