fs/smbfs/file.c

   1 /*
   2  *  file.c
   3  *
   4  *  Copyright (C) 1995, 1996, 1997 by Paal-Kr. Engstad and Volker Lendecke
   5  *  Copyright (C) 1997 by Volker Lendecke
   6  *
   7  *  Please add a note about your changes to smbfs in the ChangeLog file.
   8  */
   9
  10 #include <linux/sched.h>
  11 #include <linux/kernel.h>
  12 #include <linux/errno.h>
  13 #include <linux/fcntl.h>
  14 #include <linux/stat.h>
  15 #include <linux/mm.h>
  16 #include <linux/malloc.h>
  17 #include <linux/pagemap.h>
  18 #include <linux/smp_lock.h>
  19
  20 #include <asm/uaccess.h>
  21 #include <asm/system.h>
  22
  23 #include <linux/smbno.h>
  24 #include <linux/smb_fs.h>
  25
  26 #include "smb_debug.h"
  27
  28 static int
  29 smb_fsync(struct file *file, struct dentry * dentry, int datasync)
  30 {
  31         VERBOSE("sync file %s/%s\n", DENTRY_PATH(dentry));
  32         return 0;
  33 }
  34
  35 /*
  36  * Read a page synchronously.
  37  */
  38 static int
  39 smb_readpage_sync(struct dentry *dentry, struct page *page)
  40 {
  41         char *buffer = page_address(page);
  42         unsigned long offset = page->index << PAGE_CACHE_SHIFT;
  43         int rsize = smb_get_rsize(server_from_dentry(dentry));
  44         int count = PAGE_SIZE;
  45         int result;
  46
  47         VERBOSE("file %s/%s, count=%d@%ld, rsize=%d\n",
  48                 DENTRY_PATH(dentry), count, offset, rsize);
  49
  50         result = smb_open(dentry, SMB_O_RDONLY);
  51         if (result < 0)
  52         {
  53                 PARANOIA("%s/%s open failed, error=%d\n",
  54                          DENTRY_PATH(dentry), result);
  55                 goto io_error;
  56         }
  57
  58         do {
  59                 if (count < rsize)
  60                         rsize = count;
  61
  62                 result = smb_proc_read(dentry, offset, rsize, buffer);
  63                 if (result < 0)
  64                         goto io_error;
  65
  66                 count -= result;
  67                 offset += result;
  68                 buffer += result;
  69                 dentry->d_inode->i_atime = CURRENT_TIME;
  70                 if (result < rsize)
  71                         break;
  72         } while (count);
  73
  74         memset(buffer, 0, count);
  75         flush_dcache_page(page);
  76         SetPageUptodate(page);
  77         result = 0;
  78
  79 io_error:
  80         UnlockPage(page);
  81         return result;
  82 }
  83
  84 /*
  85  * We are called with the page locked and the caller unlocks.
  86  */
  87 static int
  88 smb_readpage(struct file *file, struct page *page)
  89 {
  90         int             error;
  91         struct dentry  *dentry = file->f_dentry;
  92
  93         DEBUG1("readpage %p\n", page_address(page));
  94
  95         get_page(page);
  96         error = smb_readpage_sync(dentry, page);
  97         put_page(page);
  98         return error;
  99 }
 100
 101 /*
 102  * Write a page synchronously.
 103  * Offset is the data offset within the page.
 104  */
 105 static int
 106 smb_writepage_sync(struct dentry *dentry, struct page *page,
 107                    unsigned long offset, unsigned int count)
 108 {
 109         struct inode *inode = dentry->d_inode;
 110         u8 *buffer = page_address(page) + offset;
 111         int wsize = smb_get_wsize(server_from_dentry(dentry));
 112         int result, written = 0;
 113
 114         offset += page->index << PAGE_CACHE_SHIFT;
 115         VERBOSE("file %s/%s, count=%d@%ld, wsize=%d\n",
 116                 DENTRY_PATH(dentry), count, offset, wsize);
 117
 118         do {
 119                 if (count < wsize)
 120                         wsize = count;
 121
 122                 result = smb_proc_write(dentry, offset, wsize, buffer);
 123                 if (result < 0)
 124                         break;
 125                 /* N.B. what if result < wsize?? */
 126 #ifdef SMBFS_PARANOIA
 127                 if (result < wsize)
 128                         PARANOIA("short write, wsize=%d, result=%d\n",
 129                                  wsize, result);
 130 #endif
 131                 buffer += wsize;
 132                 offset += wsize;
 133                 written += wsize;
 134                 count -= wsize;
 135                 /*
 136                  * Update the inode now rather than waiting for a refresh.
 137                  */
 138                 inode->i_mtime = inode->i_atime = CURRENT_TIME;
 139                 if (offset > inode->i_size)
 140                         inode->i_size = offset;
 141                 inode->u.smbfs_i.cache_valid |= SMB_F_LOCALWRITE;
 142         } while (count);
 143         return written ? written : result;
 144 }
 145
 146 /*
 147  * Write a page to the server. This will be used for NFS swapping only
 148  * (for now), and we currently do this synchronously only.
 149  *
 150  * We are called with the page locked and the caller unlocks.
 151  */
 152 static int
 153 smb_writepage(struct file *file, struct page *page)
 154 {
 155         struct dentry *dentry = file->f_dentry;
 156         struct inode *inode = dentry->d_inode;
 157         unsigned long end_index = inode->i_size >> PAGE_CACHE_SHIFT;
 158         unsigned offset = PAGE_CACHE_SIZE;
 159         int err;
 160
 161         /* easy case */
 162         if (page->index < end_index)
 163                 goto do_it;
 164         /* things got complicated... */
 165         offset = inode->i_size & (PAGE_CACHE_SIZE-1);
 166         /* OK, are we completely out? */
 167         if (page->index >= end_index+1 || !offset)
 168                 return -EIO;
 169 do_it:
 170         get_page(page);
 171         err = smb_writepage_sync(dentry, page, 0, offset);
 172         SetPageUptodate(page);
 173         put_page(page);
 174         return err;
 175 }
 176
 177 static int
 178 smb_updatepage(struct file *file, struct page *page, unsigned long offset,
 179                unsigned int count)
 180 {
 181         struct dentry *dentry = file->f_dentry;
 182
 183         DEBUG1("(%s/%s %d@%ld)\n", DENTRY_PATH(dentry),
 184                count, (page->index << PAGE_CACHE_SHIFT)+offset);
 185
 186         return smb_writepage_sync(dentry, page, offset, count);
 187 }
 188
 189 static ssize_t
 190 smb_file_read(struct file * file, char * buf, size_t count, loff_t *ppos)
 191 {
 192         struct dentry * dentry = file->f_dentry;
 193         ssize_t status;
 194
 195         VERBOSE("file %s/%s, count=%lu@%lu\n", DENTRY_PATH(dentry),
 196                 (unsigned long) count, (unsigned long) *ppos);
 197
 198         status = smb_revalidate_inode(dentry);
 199         if (status)
 200         {
 201                 PARANOIA("%s/%s validation failed, error=%Zd\n",
 202                          DENTRY_PATH(dentry), status);
 203                 goto out;
 204         }
 205
 206         VERBOSE("before read, size=%ld, flags=%x, atime=%ld\n",
 207                 (long)dentry->d_inode->i_size,
 208                 dentry->d_inode->i_flags, dentry->d_inode->i_atime);
 209
 210         status = generic_file_read(file, buf, count, ppos);
 211 out:
 212         return status;
 213 }
 214
 215 static int
 216 smb_file_mmap(struct file * file, struct vm_area_struct * vma)
 217 {
 218         struct dentry * dentry = file->f_dentry;
 219         int     status;
 220
 221         VERBOSE("file %s/%s, address %lu - %lu\n",
 222                 DENTRY_PATH(dentry), vma->vm_start, vma->vm_end);
 223
 224         status = smb_revalidate_inode(dentry);
 225         if (status)
 226         {
 227                 PARANOIA("%s/%s validation failed, error=%d\n",
 228                          DENTRY_PATH(dentry), status);
 229                 goto out;
 230         }
 231         status = generic_file_mmap(file, vma);
 232 out:
 233         return status;
 234 }
 235
 236 /*
 237  * This does the "real" work of the write. The generic routine has
 238  * allocated the page, locked it, done all the page alignment stuff
 239  * calculations etc. Now we should just copy the data from user
 240  * space and write it back to the real medium..
 241  *
 242  * If the writer ends up delaying the write, the writer needs to
 243  * increment the page use counts until he is done with the page.
 244  */
 245 static int smb_prepare_write(struct file *file, struct page *page,
 246                              unsigned offset, unsigned to)
 247 {
 248         kmap(page);
 249         return 0;
 250 }
 251
 252 static int smb_commit_write(struct file *file, struct page *page,
 253                             unsigned offset, unsigned to)
 254 {
 255         int status;
 256
 257         status = -EFAULT;
 258         lock_kernel();
 259         status = smb_updatepage(file, page, offset, to-offset);
 260         unlock_kernel();
 261         kunmap(page);
 262         return status;
 263 }
 264
 265 struct address_space_operations smb_file_aops = {
 266         readpage: smb_readpage,
 267         writepage: smb_writepage,
 268         prepare_write: smb_prepare_write,
 269         commit_write: smb_commit_write
 270 };
 271
 272 /*
 273  * Write to a file (through the page cache).
 274  */
 275 static ssize_t
 276 smb_file_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
 277 {
 278         struct dentry * dentry = file->f_dentry;
 279         ssize_t result;
 280
 281         VERBOSE("file %s/%s, count=%lu@%lu\n",
 282                 DENTRY_PATH(dentry),
 283                 (unsigned long) count, (unsigned long) *ppos);
 284
 285         result = smb_revalidate_inode(dentry);
 286         if (result)
 287         {
 288                 PARANOIA("%s/%s validation failed, error=%Zd\n",
 289                          DENTRY_PATH(dentry), result);
 290                 goto out;
 291         }
 292
 293         result = smb_open(dentry, SMB_O_WRONLY);
 294         if (result)
 295                 goto out;
 296
 297         if (count > 0)
 298         {
 299                 result = generic_file_write(file, buf, count, ppos);
 300                 VERBOSE("pos=%ld, size=%ld, mtime=%ld, atime=%ld\n",
 301                         (long) file->f_pos, (long) dentry->d_inode->i_size,
 302                         dentry->d_inode->i_mtime, dentry->d_inode->i_atime);
 303         }
 304 out:
 305         return result;
 306 }
 307
 308 static int
 309 smb_file_open(struct inode *inode, struct file * file)
 310 {
 311         lock_kernel();
 312         inode->u.smbfs_i.openers++;
 313         unlock_kernel();
 314         return 0;
 315 }
 316
 317 static int
 318 smb_file_release(struct inode *inode, struct file * file)
 319 {
 320         lock_kernel();
 321         if (!--inode->u.smbfs_i.openers)
 322                 smb_close(inode);
 323         unlock_kernel();
 324         return 0;
 325 }
 326
 327 /*
 328  * Check whether the required access is compatible with
 329  * an inode's permission. SMB doesn't recognize superuser
 330  * privileges, so we need our own check for this.
 331  */
 332 static int
 333 smb_file_permission(struct inode *inode, int mask)
 334 {
 335         int mode = inode->i_mode;
 336         int error = 0;
 337
 338         VERBOSE("mode=%x, mask=%x\n", mode, mask);
 339
 340         /* Look at user permissions */
 341         mode >>= 6;
 342         if ((mode & 7 & mask) != mask)
 343                 error = -EACCES;
 344         return error;
 345 }
 346
 347 struct file_operations smb_file_operations =
 348 {
 349         read:           smb_file_read,
 350         write:          smb_file_write,
 351         ioctl:          smb_ioctl,
 352         mmap:           smb_file_mmap,
 353         open:           smb_file_open,
 354         release:        smb_file_release,
 355         fsync:          smb_fsync,
 356 };
 357
 358 struct inode_operations smb_file_inode_operations =
 359 {
 360         permission:     smb_file_permission,
 361         revalidate:     smb_revalidate_inode,
 362         setattr:        smb_notify_change,
 363 };