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/time.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/slab.h>
  17 #include <linux/pagemap.h>
  18 #include <linux/smp_lock.h>
  19 #include <linux/net.h>
  20
  21 #include <asm/uaccess.h>
  22 #include <asm/system.h>
  23
  24 #include <linux/smbno.h>
  25 #include <linux/smb_fs.h>
  26
  27 #include "smb_debug.h"
  28 #include "proto.h"
  29
  30 static int
  31 smb_fsync(struct file *file, struct dentry * dentry, int datasync)
  32 {
  33         struct smb_sb_info *server = server_from_dentry(dentry);
  34         int result;
  35
  36         VERBOSE("sync file %s/%s\n", DENTRY_PATH(dentry));
  37
  38         /*
  39          * The VFS will writepage() all dirty pages for us, but we
  40          * should send a SMBflush to the server, letting it know that
  41          * we want things synchronized with actual storage.
  42          *
  43          * Note: this function requires all pages to have been written already
  44          *       (should be ok with writepage_sync)
  45          */
  46         result = smb_proc_flush(server, SMB_I(dentry->d_inode)->fileid);
  47         return result;
  48 }
  49
  50 /*
  51  * Read a page synchronously.
  52  */
  53 static int
  54 smb_readpage_sync(struct dentry *dentry, struct page *page)
  55 {
  56         char *buffer = kmap(page);
  57         loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
  58         struct smb_sb_info *server = server_from_dentry(dentry);
  59         unsigned int rsize = smb_get_rsize(server);
  60         int count = PAGE_SIZE;
  61         int result;
  62
  63         VERBOSE("file %s/%s, count=%d@%Ld, rsize=%d\n",
  64                 DENTRY_PATH(dentry), count, offset, rsize);
  65
  66         result = smb_open(dentry, SMB_O_RDONLY);
  67         if (result < 0)
  68                 goto io_error;
  69
  70         do {
  71                 if (count < rsize)
  72                         rsize = count;
  73
  74                 result = server->ops->read(dentry->d_inode,offset,rsize,buffer);
  75                 if (result < 0)
  76                         goto io_error;
  77
  78                 count -= result;
  79                 offset += result;
  80                 buffer += result;
  81                 dentry->d_inode->i_atime = CURRENT_TIME;
  82                 if (result < rsize)
  83                         break;
  84         } while (count);
  85
  86         memset(buffer, 0, count);
  87         flush_dcache_page(page);
  88         SetPageUptodate(page);
  89         result = 0;
  90
  91 io_error:
  92         kunmap(page);
  93         unlock_page(page);
  94         return result;
  95 }
  96
  97 /*
  98  * We are called with the page locked and we unlock it when done.
  99  */
 100 static int
 101 smb_readpage(struct file *file, struct page *page)
 102 {
 103         int             error;
 104         struct dentry  *dentry = file->f_dentry;
 105
 106         page_cache_get(page);
 107         error = smb_readpage_sync(dentry, page);
 108         page_cache_release(page);
 109         return error;
 110 }
 111
 112 /*
 113  * Write a page synchronously.
 114  * Offset is the data offset within the page.
 115  */
 116 static int
 117 smb_writepage_sync(struct inode *inode, struct page *page,
 118                    unsigned long pageoffset, unsigned int count)
 119 {
 120         loff_t offset;
 121         char *buffer = kmap(page) + pageoffset;
 122         struct smb_sb_info *server = server_from_inode(inode);
 123         unsigned int wsize = smb_get_wsize(server);
 124         int ret = 0;
 125
 126         offset = ((loff_t)page->index << PAGE_CACHE_SHIFT) + pageoffset;
 127         VERBOSE("file ino=%ld, fileid=%d, count=%d@%Ld, wsize=%d\n",
 128                 inode->i_ino, SMB_I(inode)->fileid, count, offset, wsize);
 129
 130         do {
 131                 int write_ret;
 132
 133                 if (count < wsize)
 134                         wsize = count;
 135
 136                 write_ret = server->ops->write(inode, offset, wsize, buffer);
 137                 if (write_ret < 0) {
 138                         PARANOIA("failed write, wsize=%d, write_ret=%d\n",
 139                                  wsize, write_ret);
 140                         ret = write_ret;
 141                         break;
 142                 }
 143                 /* N.B. what if result < wsize?? */
 144 #ifdef SMBFS_PARANOIA
 145                 if (write_ret < wsize)
 146                         PARANOIA("short write, wsize=%d, write_ret=%d\n",
 147                                  wsize, write_ret);
 148 #endif
 149                 buffer += wsize;
 150                 offset += wsize;
 151                 count -= wsize;
 152                 /*
 153                  * Update the inode now rather than waiting for a refresh.
 154                  */
 155                 inode->i_mtime = inode->i_atime = CURRENT_TIME;
 156                 SMB_I(inode)->flags |= SMB_F_LOCALWRITE;
 157                 if (offset > inode->i_size)
 158                         inode->i_size = offset;
 159         } while (count);
 160
 161         kunmap(page);
 162         return ret;
 163 }
 164
 165 /*
 166  * Write a page to the server. This will be used for NFS swapping only
 167  * (for now), and we currently do this synchronously only.
 168  *
 169  * We are called with the page locked and we unlock it when done.
 170  */
 171 static int
 172 smb_writepage(struct page *page, struct writeback_control *wbc)
 173 {
 174         struct address_space *mapping = page->mapping;
 175         struct inode *inode;
 176         unsigned long end_index;
 177         unsigned offset = PAGE_CACHE_SIZE;
 178         int err;
 179
 180         if (!mapping)
 181                 BUG();
 182         inode = mapping->host;
 183         if (!inode)
 184                 BUG();
 185
 186         end_index = inode->i_size >> PAGE_CACHE_SHIFT;
 187
 188         /* easy case */
 189         if (page->index < end_index)
 190                 goto do_it;
 191         /* things got complicated... */
 192         offset = inode->i_size & (PAGE_CACHE_SIZE-1);
 193         /* OK, are we completely out? */
 194         if (page->index >= end_index+1 || !offset)
 195                 return 0; /* truncated - don't care */
 196 do_it:
 197         page_cache_get(page);
 198         err = smb_writepage_sync(inode, page, 0, offset);
 199         SetPageUptodate(page);
 200         unlock_page(page);
 201         page_cache_release(page);
 202         return err;
 203 }
 204
 205 static int
 206 smb_updatepage(struct file *file, struct page *page, unsigned long offset,
 207                unsigned int count)
 208 {
 209         struct dentry *dentry = file->f_dentry;
 210
 211         DEBUG1("(%s/%s %d@%ld)\n", DENTRY_PATH(dentry),
 212                count, (page->index << PAGE_CACHE_SHIFT)+offset);
 213
 214         return smb_writepage_sync(dentry->d_inode, page, offset, count);
 215 }
 216
 217 static ssize_t
 218 smb_file_read(struct file * file, char __user * buf, size_t count, loff_t *ppos)
 219 {
 220         struct dentry * dentry = file->f_dentry;
 221         ssize_t status;
 222
 223         VERBOSE("file %s/%s, count=%lu@%lu\n", DENTRY_PATH(dentry),
 224                 (unsigned long) count, (unsigned long) *ppos);
 225
 226         status = smb_revalidate_inode(dentry);
 227         if (status) {
 228                 PARANOIA("%s/%s validation failed, error=%Zd\n",
 229                          DENTRY_PATH(dentry), status);
 230                 goto out;
 231         }
 232
 233         VERBOSE("before read, size=%ld, flags=%x, atime=%ld\n",
 234                 (long)dentry->d_inode->i_size,
 235                 dentry->d_inode->i_flags, dentry->d_inode->i_atime);
 236
 237         status = generic_file_read(file, buf, count, ppos);
 238 out:
 239         return status;
 240 }
 241
 242 static int
 243 smb_file_mmap(struct file * file, struct vm_area_struct * vma)
 244 {
 245         struct dentry * dentry = file->f_dentry;
 246         int     status;
 247
 248         VERBOSE("file %s/%s, address %lu - %lu\n",
 249                 DENTRY_PATH(dentry), vma->vm_start, vma->vm_end);
 250
 251         status = smb_revalidate_inode(dentry);
 252         if (status) {
 253                 PARANOIA("%s/%s validation failed, error=%d\n",
 254                          DENTRY_PATH(dentry), status);
 255                 goto out;
 256         }
 257         status = generic_file_mmap(file, vma);
 258 out:
 259         return status;
 260 }
 261
 262 static ssize_t
 263 smb_file_sendfile(struct file *file, loff_t *ppos,
 264                   size_t count, read_actor_t actor, void *target)
 265 {
 266         struct dentry *dentry = file->f_dentry;
 267         ssize_t status;
 268
 269         VERBOSE("file %s/%s, pos=%Ld, count=%d\n",
 270                 DENTRY_PATH(dentry), *ppos, count);
 271
 272         status = smb_revalidate_inode(dentry);
 273         if (status) {
 274                 PARANOIA("%s/%s validation failed, error=%Zd\n",
 275                          DENTRY_PATH(dentry), status);
 276                 goto out;
 277         }
 278         status = generic_file_sendfile(file, ppos, count, actor, target);
 279 out:
 280         return status;
 281 }
 282
 283 /*
 284  * This does the "real" work of the write. The generic routine has
 285  * allocated the page, locked it, done all the page alignment stuff
 286  * calculations etc. Now we should just copy the data from user
 287  * space and write it back to the real medium..
 288  *
 289  * If the writer ends up delaying the write, the writer needs to
 290  * increment the page use counts until he is done with the page.
 291  */
 292 static int smb_prepare_write(struct file *file, struct page *page,
 293                              unsigned offset, unsigned to)
 294 {
 295         return 0;
 296 }
 297
 298 static int smb_commit_write(struct file *file, struct page *page,
 299                             unsigned offset, unsigned to)
 300 {
 301         int status;
 302
 303         status = -EFAULT;
 304         lock_kernel();
 305         status = smb_updatepage(file, page, offset, to-offset);
 306         unlock_kernel();
 307         return status;
 308 }
 309
 310 struct address_space_operations smb_file_aops = {
 311         .readpage = smb_readpage,
 312         .writepage = smb_writepage,
 313         .prepare_write = smb_prepare_write,
 314         .commit_write = smb_commit_write
 315 };
 316
 317 /*
 318  * Write to a file (through the page cache).
 319  */
 320 static ssize_t
 321 smb_file_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 322 {
 323         struct dentry * dentry = file->f_dentry;
 324         ssize_t result;
 325
 326         VERBOSE("file %s/%s, count=%lu@%lu\n",
 327                 DENTRY_PATH(dentry),
 328                 (unsigned long) count, (unsigned long) *ppos);
 329
 330         result = smb_revalidate_inode(dentry);
 331         if (result) {
 332                 PARANOIA("%s/%s validation failed, error=%Zd\n",
 333                          DENTRY_PATH(dentry), result);
 334                 goto out;
 335         }
 336
 337         result = smb_open(dentry, SMB_O_WRONLY);
 338         if (result)
 339                 goto out;
 340
 341         if (count > 0) {
 342                 result = generic_file_write(file, buf, count, ppos);
 343                 VERBOSE("pos=%ld, size=%ld, mtime=%ld, atime=%ld\n",
 344                         (long) file->f_pos, (long) dentry->d_inode->i_size,
 345                         dentry->d_inode->i_mtime, dentry->d_inode->i_atime);
 346         }
 347 out:
 348         return result;
 349 }
 350
 351 static int
 352 smb_file_open(struct inode *inode, struct file * file)
 353 {
 354         int result;
 355         struct dentry *dentry = file->f_dentry;
 356         int smb_mode = (file->f_mode & O_ACCMODE) - 1;
 357
 358         lock_kernel();
 359         result = smb_open(dentry, smb_mode);
 360         if (result)
 361                 goto out;
 362         SMB_I(inode)->openers++;
 363 out:
 364         unlock_kernel();
 365         return 0;
 366 }
 367
 368 static int
 369 smb_file_release(struct inode *inode, struct file * file)
 370 {
 371         lock_kernel();
 372         if (!--SMB_I(inode)->openers) {
 373                 /* We must flush any dirty pages now as we won't be able to
 374                    write anything after close. mmap can trigger this.
 375                    "openers" should perhaps include mmap'ers ... */
 376                 filemap_fdatawrite(inode->i_mapping);
 377                 filemap_fdatawait(inode->i_mapping);
 378                 smb_close(inode);
 379         }
 380         unlock_kernel();
 381         return 0;
 382 }
 383
 384 /*
 385  * Check whether the required access is compatible with
 386  * an inode's permission. SMB doesn't recognize superuser
 387  * privileges, so we need our own check for this.
 388  */
 389 static int
 390 smb_file_permission(struct inode *inode, int mask, struct nameidata *nd)
 391 {
 392         int mode = inode->i_mode;
 393         int error = 0;
 394
 395         VERBOSE("mode=%x, mask=%x\n", mode, mask);
 396
 397         /* Look at user permissions */
 398         mode >>= 6;
 399         if ((mode & 7 & mask) != mask)
 400                 error = -EACCES;
 401         return error;
 402 }
 403
 404 struct file_operations smb_file_operations =
 405 {
 406         .llseek         = remote_llseek,
 407         .read           = smb_file_read,
 408         .write          = smb_file_write,
 409         .ioctl          = smb_ioctl,
 410         .mmap           = smb_file_mmap,
 411         .open           = smb_file_open,
 412         .release        = smb_file_release,
 413         .fsync          = smb_fsync,
 414         .sendfile       = smb_file_sendfile,
 415 };
 416
 417 struct inode_operations smb_file_inode_operations =
 418 {
 419         .permission     = smb_file_permission,
 420         .getattr        = smb_getattr,
 421         .setattr        = smb_notify_change,
 422 };