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 <linux/pagemap.h>
  36 #include <asm/uaccess.h>
  37 #include <linux/idr.h>
  38 #include <net/9p/9p.h>
  39 #include <net/9p/client.h>
  40
  41 #include "v9fs.h"
  42 #include "v9fs_vfs.h"
  43 #include "fid.h"
  44 #include "cache.h"
  45
  46 static const struct file_operations v9fs_cached_file_operations;
  47
  48 /**
  49  * v9fs_file_open - open a file (or directory)
  50  * @inode: inode to be opened
  51  * @file: file being opened
  52  *
  53  */
  54
  55 int v9fs_file_open(struct inode *inode, struct file *file)
  56 {
  57         int err;
  58         struct v9fs_session_info *v9ses;
  59         struct p9_fid *fid;
  60         int omode;
  61
  62         P9_DPRINTK(P9_DEBUG_VFS, "inode: %p file: %p \n", inode, file);
  63         v9ses = v9fs_inode2v9ses(inode);
  64         omode = v9fs_uflags2omode(file->f_flags, v9fs_extended(v9ses));
  65         fid = file->private_data;
  66         if (!fid) {
  67                 fid = v9fs_fid_clone(file->f_path.dentry);
  68                 if (IS_ERR(fid))
  69                         return PTR_ERR(fid);
  70
  71                 err = p9_client_open(fid, omode);
  72                 if (err < 0) {
  73                         p9_client_clunk(fid);
  74                         return err;
  75                 }
  76                 if (omode & P9_OTRUNC) {
  77                         i_size_write(inode, 0);
  78                         inode->i_blocks = 0;
  79                 }
  80                 if ((file->f_flags & O_APPEND) && (!v9fs_extended(v9ses)))
  81                         generic_file_llseek(file, 0, SEEK_END);
  82         }
  83
  84         file->private_data = fid;
  85         if ((fid->qid.version) && (v9ses->cache)) {
  86                 P9_DPRINTK(P9_DEBUG_VFS, "cached");
  87                 /* enable cached file options */
  88                 if(file->f_op == &v9fs_file_operations)
  89                         file->f_op = &v9fs_cached_file_operations;
  90
  91 #ifdef CONFIG_9P_FSCACHE
  92                 v9fs_cache_inode_set_cookie(inode, file);
  93 #endif
  94         }
  95
  96         return 0;
  97 }
  98
  99 /**
 100  * v9fs_file_lock - lock a file (or directory)
 101  * @filp: file to be locked
 102  * @cmd: lock command
 103  * @fl: file lock structure
 104  *
 105  * Bugs: this looks like a local only lock, we should extend into 9P
 106  *       by using open exclusive
 107  */
 108
 109 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
 110 {
 111         int res = 0;
 112         struct inode *inode = filp->f_path.dentry->d_inode;
 113
 114         P9_DPRINTK(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
 115
 116         /* No mandatory locks */
 117         if (__mandatory_lock(inode))
 118                 return -ENOLCK;
 119
 120         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 121                 filemap_write_and_wait(inode->i_mapping);
 122                 invalidate_mapping_pages(&inode->i_data, 0, -1);
 123         }
 124
 125         return res;
 126 }
 127
 128 /**
 129  * v9fs_file_readn - read from a file
 130  * @filp: file pointer to read
 131  * @data: data buffer to read data into
 132  * @udata: user data buffer to read data into
 133  * @count: size of buffer
 134  * @offset: offset at which to read data
 135  *
 136  */
 137
 138 ssize_t
 139 v9fs_file_readn(struct file *filp, char *data, char __user *udata, u32 count,
 140                u64 offset)
 141 {
 142         int n, total;
 143         struct p9_fid *fid = filp->private_data;
 144
 145         P9_DPRINTK(P9_DEBUG_VFS, "fid %d offset %llu count %d\n", fid->fid,
 146                                         (long long unsigned) offset, count);
 147
 148         n = 0;
 149         total = 0;
 150         do {
 151                 n = p9_client_read(fid, data, udata, offset, count);
 152                 if (n <= 0)
 153                         break;
 154
 155                 if (data)
 156                         data += n;
 157                 if (udata)
 158                         udata += n;
 159
 160                 offset += n;
 161                 count -= n;
 162                 total += n;
 163         } while (count > 0 && n == (fid->clnt->msize - P9_IOHDRSZ));
 164
 165         if (n < 0)
 166                 total = n;
 167
 168         return total;
 169 }
 170
 171 /**
 172  * v9fs_file_read - read from a file
 173  * @filp: file pointer to read
 174  * @udata: user data buffer to read data into
 175  * @count: size of buffer
 176  * @offset: offset at which to read data
 177  *
 178  */
 179
 180 static ssize_t
 181 v9fs_file_read(struct file *filp, char __user *udata, size_t count,
 182                loff_t * offset)
 183 {
 184         int ret;
 185         struct p9_fid *fid;
 186
 187         P9_DPRINTK(P9_DEBUG_VFS, "count %zu offset %lld\n", count, *offset);
 188         fid = filp->private_data;
 189
 190         if (count > (fid->clnt->msize - P9_IOHDRSZ))
 191                 ret = v9fs_file_readn(filp, NULL, udata, count, *offset);
 192         else
 193                 ret = p9_client_read(fid, NULL, udata, *offset, count);
 194
 195         if (ret > 0)
 196                 *offset += ret;
 197
 198         return ret;
 199 }
 200
 201 /**
 202  * v9fs_file_write - write to a file
 203  * @filp: file pointer to write
 204  * @data: data buffer to write data from
 205  * @count: size of buffer
 206  * @offset: offset at which to write data
 207  *
 208  */
 209
 210 static ssize_t
 211 v9fs_file_write(struct file *filp, const char __user * data,
 212                 size_t count, loff_t * offset)
 213 {
 214         int n, rsize, total = 0;
 215         struct p9_fid *fid;
 216         struct p9_client *clnt;
 217         struct inode *inode = filp->f_path.dentry->d_inode;
 218         int origin = *offset;
 219         unsigned long pg_start, pg_end;
 220
 221         P9_DPRINTK(P9_DEBUG_VFS, "data %p count %d offset %x\n", data,
 222                 (int)count, (int)*offset);
 223
 224         fid = filp->private_data;
 225         clnt = fid->clnt;
 226
 227         rsize = fid->iounit;
 228         if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
 229                 rsize = clnt->msize - P9_IOHDRSZ;
 230
 231         do {
 232                 if (count < rsize)
 233                         rsize = count;
 234
 235                 n = p9_client_write(fid, NULL, data+total, origin+total,
 236                                                                         rsize);
 237                 if (n <= 0)
 238                         break;
 239                 count -= n;
 240                 total += n;
 241         } while (count > 0);
 242
 243         if (total > 0) {
 244                 pg_start = origin >> PAGE_CACHE_SHIFT;
 245                 pg_end = (origin + total - 1) >> PAGE_CACHE_SHIFT;
 246                 if (inode->i_mapping && inode->i_mapping->nrpages)
 247                         invalidate_inode_pages2_range(inode->i_mapping,
 248                                                       pg_start, pg_end);
 249                 *offset += total;
 250                 i_size_write(inode, i_size_read(inode) + total);
 251                 inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
 252         }
 253
 254         if (n < 0)
 255                 return n;
 256
 257         return total;
 258 }
 259
 260 static const struct file_operations v9fs_cached_file_operations = {
 261         .llseek = generic_file_llseek,
 262         .read = do_sync_read,
 263         .aio_read = generic_file_aio_read,
 264         .write = v9fs_file_write,
 265         .open = v9fs_file_open,
 266         .release = v9fs_dir_release,
 267         .lock = v9fs_file_lock,
 268         .mmap = generic_file_readonly_mmap,
 269 };
 270
 271 const struct file_operations v9fs_file_operations = {
 272         .llseek = generic_file_llseek,
 273         .read = v9fs_file_read,
 274         .write = v9fs_file_write,
 275         .open = v9fs_file_open,
 276         .release = v9fs_dir_release,
 277         .lock = v9fs_file_lock,
 278         .mmap = generic_file_readonly_mmap,
 279 };