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