fs/9p/vfs_file.c

   1 /*
   2  *  linux/fs/9p/vfs_file.c
   3  *
   4  * This file contians vfs file ops for 9P2000.
   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/sched.h>
  30 #include <linux/file.h>
  31 #include <linux/stat.h>
  32 #include <linux/string.h>
  33 #include <linux/inet.h>
  34 #include <linux/list.h>
  35 #include <asm/uaccess.h>
  36 #include <linux/idr.h>
  37 #include <net/9p/9p.h>
  38 #include <net/9p/client.h>
  39
  40 #include "v9fs.h"
  41 #include "v9fs_vfs.h"
  42 #include "fid.h"
  43
  44 static const struct file_operations v9fs_cached_file_operations;
  45
  46 /**
  47  * v9fs_file_open - open a file (or directory)
  48  * @inode: inode to be opened
  49  * @file: file being opened
  50  *
  51  */
  52
  53 int v9fs_file_open(struct inode *inode, struct file *file)
  54 {
  55         int err;
  56         struct v9fs_session_info *v9ses;
  57         struct p9_fid *fid;
  58         int omode;
  59
  60         P9_DPRINTK(P9_DEBUG_VFS, "inode: %p file: %p \n", inode, file);
  61         v9ses = v9fs_inode2v9ses(inode);
  62         omode = v9fs_uflags2omode(file->f_flags, v9fs_extended(v9ses));
  63         fid = file->private_data;
  64         if (!fid) {
  65                 fid = v9fs_fid_clone(file->f_path.dentry);
  66                 if (IS_ERR(fid))
  67                         return PTR_ERR(fid);
  68
  69                 err = p9_client_open(fid, omode);
  70                 if (err < 0) {
  71                         p9_client_clunk(fid);
  72                         return err;
  73                 }
  74                 if (omode & P9_OTRUNC) {
  75                         inode->i_size = 0;
  76                         inode->i_blocks = 0;
  77                 }
  78                 if ((file->f_flags & O_APPEND) && (!v9fs_extended(v9ses)))
  79                         generic_file_llseek(file, 0, SEEK_END);
  80         }
  81
  82         file->private_data = fid;
  83         if ((fid->qid.version) && (v9ses->cache)) {
  84                 P9_DPRINTK(P9_DEBUG_VFS, "cached");
  85                 /* enable cached file options */
  86                 if(file->f_op == &v9fs_file_operations)
  87                         file->f_op = &v9fs_cached_file_operations;
  88         }
  89
  90         return 0;
  91 }
  92
  93 /**
  94  * v9fs_file_lock - lock a file (or directory)
  95  * @filp: file to be locked
  96  * @cmd: lock command
  97  * @fl: file lock structure
  98  *
  99  * Bugs: this looks like a local only lock, we should extend into 9P
 100  *       by using open exclusive
 101  */
 102
 103 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
 104 {
 105         int res = 0;
 106         struct inode *inode = filp->f_path.dentry->d_inode;
 107
 108         P9_DPRINTK(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
 109
 110         /* No mandatory locks */
 111         if (__mandatory_lock(inode))
 112                 return -ENOLCK;
 113
 114         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 115                 filemap_write_and_wait(inode->i_mapping);
 116                 invalidate_mapping_pages(&inode->i_data, 0, -1);
 117         }
 118
 119         return res;
 120 }
 121
 122 /**
 123  * v9fs_file_readn - read from a file
 124  * @filp: file pointer to read
 125  * @data: data buffer to read data into
 126  * @udata: user data buffer to read data into
 127  * @count: size of buffer
 128  * @offset: offset at which to read data
 129  *
 130  */
 131
 132 ssize_t
 133 v9fs_file_readn(struct file *filp, char *data, char __user *udata, u32 count,
 134                u64 offset)
 135 {
 136         int n, total;
 137         struct p9_fid *fid = filp->private_data;
 138
 139         P9_DPRINTK(P9_DEBUG_VFS, "fid %d offset %llu count %d\n", fid->fid,
 140                                         (long long unsigned) offset, count);
 141
 142         n = 0;
 143         total = 0;
 144         do {
 145                 n = p9_client_read(fid, data, udata, offset, count);
 146                 if (n <= 0)
 147                         break;
 148
 149                 if (data)
 150                         data += n;
 151                 if (udata)
 152                         udata += n;
 153
 154                 offset += n;
 155                 count -= n;
 156                 total += n;
 157         } while (count > 0 && n == (fid->clnt->msize - P9_IOHDRSZ));
 158
 159         if (n < 0)
 160                 total = n;
 161
 162         return total;
 163 }
 164
 165 /**
 166  * v9fs_file_read - read from a file
 167  * @filp: file pointer to read
 168  * @udata: user data buffer to read data into
 169  * @count: size of buffer
 170  * @offset: offset at which to read data
 171  *
 172  */
 173
 174 static ssize_t
 175 v9fs_file_read(struct file *filp, char __user *udata, size_t count,
 176                loff_t * offset)
 177 {
 178         int ret;
 179         struct p9_fid *fid;
 180
 181         P9_DPRINTK(P9_DEBUG_VFS, "count %zu offset %lld\n", count, *offset);
 182         fid = filp->private_data;
 183
 184         if (count > (fid->clnt->msize - P9_IOHDRSZ))
 185                 ret = v9fs_file_readn(filp, NULL, udata, count, *offset);
 186         else
 187                 ret = p9_client_read(fid, NULL, udata, *offset, count);
 188
 189         if (ret > 0)
 190                 *offset += ret;
 191
 192         return ret;
 193 }
 194
 195 /**
 196  * v9fs_file_write - write to a file
 197  * @filp: file pointer to write
 198  * @data: data buffer to write data from
 199  * @count: size of buffer
 200  * @offset: offset at which to write data
 201  *
 202  */
 203
 204 static ssize_t
 205 v9fs_file_write(struct file *filp, const char __user * data,
 206                 size_t count, loff_t * offset)
 207 {
 208         int n, rsize, total = 0;
 209         struct p9_fid *fid;
 210         struct p9_client *clnt;
 211         struct inode *inode = filp->f_path.dentry->d_inode;
 212         int origin = *offset;
 213
 214         P9_DPRINTK(P9_DEBUG_VFS, "data %p count %d offset %x\n", data,
 215                 (int)count, (int)*offset);
 216
 217         fid = filp->private_data;
 218         clnt = fid->clnt;
 219
 220         rsize = fid->iounit;
 221         if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
 222                 rsize = clnt->msize - P9_IOHDRSZ;
 223
 224         do {
 225                 if (count < rsize)
 226                         rsize = count;
 227
 228                 n = p9_client_write(fid, NULL, data+total, *offset+total,
 229                                                                         rsize);
 230                 if (n <= 0)
 231                         break;
 232                 count -= n;
 233                 total += n;
 234         } while (count > 0);
 235
 236         if (total > 0) {
 237                 invalidate_inode_pages2_range(inode->i_mapping, origin,
 238                                                                 origin+total);
 239                 *offset += total;
 240         }
 241
 242         if (*offset > inode->i_size) {
 243                 inode->i_size = *offset;
 244                 inode->i_blocks = (inode->i_size + 512 - 1) >> 9;
 245         }
 246
 247         if (n < 0)
 248                 return n;
 249
 250         return total;
 251 }
 252
 253 static const struct file_operations v9fs_cached_file_operations = {
 254         .llseek = generic_file_llseek,
 255         .read = do_sync_read,
 256         .aio_read = generic_file_aio_read,
 257         .write = v9fs_file_write,
 258         .open = v9fs_file_open,
 259         .release = v9fs_dir_release,
 260         .lock = v9fs_file_lock,
 261         .mmap = generic_file_readonly_mmap,
 262 };
 263
 264 const struct file_operations v9fs_file_operations = {
 265         .llseek = generic_file_llseek,
 266         .read = v9fs_file_read,
 267         .write = v9fs_file_write,
 268         .open = v9fs_file_open,
 269         .release = v9fs_dir_release,
 270         .lock = v9fs_file_lock,
 271         .mmap = generic_file_readonly_mmap,
 272 };