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 #include <linux/aio.h>
  21
  22 #include <asm/uaccess.h>
  23 #include <asm/system.h>
  24
  25 #include <linux/smbno.h>
  26 #include <linux/smb_fs.h>
  27
  28 #include "smb_debug.h"
  29 #include "proto.h"
  30
  31 static int
  32 smb_fsync(struct file *file, struct dentry * dentry, int datasync)
  33 {
  34         struct smb_sb_info *server = server_from_dentry(dentry);
  35         int result;
  36
  37         VERBOSE("sync file %s/%s\n", DENTRY_PATH(dentry));
  38
  39         /*
  40          * The VFS will writepage() all dirty pages for us, but we
  41          * should send a SMBflush to the server, letting it know that
  42          * we want things synchronized with actual storage.
  43          *
  44          * Note: this function requires all pages to have been written already
  45          *       (should be ok with writepage_sync)
  46          */
  47         result = smb_proc_flush(server, SMB_I(dentry->d_inode)->fileid);
  48         return result;
  49 }
  50
  51 /*
  52  * Read a page synchronously.
  53  */
  54 static int
  55 smb_readpage_sync(struct dentry *dentry, struct page *page)
  56 {
  57         char *buffer = kmap(page);
  58         loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
  59         struct smb_sb_info *server = server_from_dentry(dentry);
  60         unsigned int rsize = smb_get_rsize(server);
  61         int count = PAGE_SIZE;
  62         int result;
  63
  64         VERBOSE("file %s/%s, count=%d@%Ld, rsize=%d\n",
  65                 DENTRY_PATH(dentry), count, offset, rsize);
  66
  67         result = smb_open(dentry, SMB_O_RDONLY);
  68         if (result < 0)
  69                 goto io_error;
  70
  71         do {
  72                 if (count < rsize)
  73                         rsize = count;
  74
  75                 result = server->ops->read(dentry->d_inode,offset,rsize,buffer);
  76                 if (result < 0)
  77                         goto io_error;
  78
  79                 count -= result;
  80                 offset += result;
  81                 buffer += result;
  82                 dentry->d_inode->i_atime =
  83                         current_fs_time(dentry->d_inode->i_sb);
  84                 if (result < rsize)
  85                         break;
  86         } while (count);
  87
  88         memset(buffer, 0, count);
  89         flush_dcache_page(page);
  90         SetPageUptodate(page);
  91         result = 0;
  92
  93 io_error:
  94         kunmap(page);
  95         unlock_page(page);
  96         return result;
  97 }
  98
  99 /*
 100  * We are called with the page locked and we unlock it when done.
 101  */
 102 static int
 103 smb_readpage(struct file *file, struct page *page)
 104 {
 105         int             error;
 106         struct dentry  *dentry = file->f_path.dentry;
 107
 108         page_cache_get(page);
 109         error = smb_readpage_sync(dentry, page);
 110         page_cache_release(page);
 111         return error;
 112 }
 113
 114 /*
 115  * Write a page synchronously.
 116  * Offset is the data offset within the page.
 117  */
 118 static int
 119 smb_writepage_sync(struct inode *inode, struct page *page,
 120                    unsigned long pageoffset, unsigned int count)
 121 {
 122         loff_t offset;
 123         char *buffer = kmap(page) + pageoffset;
 124         struct smb_sb_info *server = server_from_inode(inode);
 125         unsigned int wsize = smb_get_wsize(server);
 126         int ret = 0;
 127
 128         offset = ((loff_t)page->index << PAGE_CACHE_SHIFT) + pageoffset;
 129         VERBOSE("file ino=%ld, fileid=%d, count=%d@%Ld, wsize=%d\n",
 130                 inode->i_ino, SMB_I(inode)->fileid, count, offset, wsize);
 131
 132         do {
 133                 int write_ret;
 134
 135                 if (count < wsize)
 136                         wsize = count;
 137
 138                 write_ret = server->ops->write(inode, offset, wsize, buffer);
 139                 if (write_ret < 0) {
 140                         PARANOIA("failed write, wsize=%d, write_ret=%d\n",
 141                                  wsize, write_ret);
 142                         ret = write_ret;
 143                         break;
 144                 }
 145                 /* N.B. what if result < wsize?? */
 146 #ifdef SMBFS_PARANOIA
 147                 if (write_ret < wsize)
 148                         PARANOIA("short write, wsize=%d, write_ret=%d\n",
 149                                  wsize, write_ret);
 150 #endif
 151                 buffer += wsize;
 152                 offset += wsize;
 153                 count -= wsize;
 154                 /*
 155                  * Update the inode now rather than waiting for a refresh.
 156                  */
 157                 inode->i_mtime = inode->i_atime = current_fs_time(inode->i_sb);
 158                 SMB_I(inode)->flags |= SMB_F_LOCALWRITE;
 159                 if (offset > inode->i_size)
 160                         inode->i_size = offset;
 161         } while (count);
 162
 163         kunmap(page);
 164         return ret;
 165 }
 166
 167 /*
 168  * Write a page to the server. This will be used for NFS swapping only
 169  * (for now), and we currently do this synchronously only.
 170  *
 171  * We are called with the page locked and we unlock it when done.
 172  */
 173 static int
 174 smb_writepage(struct page *page, struct writeback_control *wbc)
 175 {
 176         struct address_space *mapping = page->mapping;
 177         struct inode *inode;
 178         unsigned long end_index;
 179         unsigned offset = PAGE_CACHE_SIZE;
 180         int err;
 181
 182         BUG_ON(!mapping);
 183         inode = mapping->host;
 184         BUG_ON(!inode);
 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_path.dentry;
 210
 211         DEBUG1("(%s/%s %d@%lld)\n", DENTRY_PATH(dentry), count,
 212                 ((unsigned long long)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_aio_read(struct kiocb *iocb, const struct iovec *iov,
 219                         unsigned long nr_segs, loff_t pos)
 220 {
 221         struct file * file = iocb->ki_filp;
 222         struct dentry * dentry = file->f_path.dentry;
 223         ssize_t status;
 224
 225         VERBOSE("file %s/%s, count=%lu@%lu\n", DENTRY_PATH(dentry),
 226                 (unsigned long) iocb->ki_left, (unsigned long) pos);
 227
 228         status = smb_revalidate_inode(dentry);
 229         if (status) {
 230                 PARANOIA("%s/%s validation failed, error=%Zd\n",
 231                          DENTRY_PATH(dentry), status);
 232                 goto out;
 233         }
 234
 235         VERBOSE("before read, size=%ld, flags=%x, atime=%ld\n",
 236                 (long)dentry->d_inode->i_size,
 237                 dentry->d_inode->i_flags, dentry->d_inode->i_atime.tv_sec);
 238
 239         status = generic_file_aio_read(iocb, iov, nr_segs, pos);
 240 out:
 241         return status;
 242 }
 243
 244 static int
 245 smb_file_mmap(struct file * file, struct vm_area_struct * vma)
 246 {
 247         struct dentry * dentry = file->f_path.dentry;
 248         int     status;
 249
 250         VERBOSE("file %s/%s, address %lu - %lu\n",
 251                 DENTRY_PATH(dentry), vma->vm_start, vma->vm_end);
 252
 253         status = smb_revalidate_inode(dentry);
 254         if (status) {
 255                 PARANOIA("%s/%s validation failed, error=%d\n",
 256                          DENTRY_PATH(dentry), status);
 257                 goto out;
 258         }
 259         status = generic_file_mmap(file, vma);
 260 out:
 261         return status;
 262 }
 263
 264 static ssize_t
 265 smb_file_splice_read(struct file *file, loff_t *ppos,
 266                      struct pipe_inode_info *pipe, size_t count,
 267                      unsigned int flags)
 268 {
 269         struct dentry *dentry = file->f_path.dentry;
 270         ssize_t status;
 271
 272         VERBOSE("file %s/%s, pos=%Ld, count=%lu\n",
 273                 DENTRY_PATH(dentry), *ppos, count);
 274
 275         status = smb_revalidate_inode(dentry);
 276         if (status) {
 277                 PARANOIA("%s/%s validation failed, error=%Zd\n",
 278                          DENTRY_PATH(dentry), status);
 279                 goto out;
 280         }
 281         status = generic_file_splice_read(file, ppos, pipe, count, flags);
 282 out:
 283         return status;
 284 }
 285
 286 /*
 287  * This does the "real" work of the write. The generic routine has
 288  * allocated the page, locked it, done all the page alignment stuff
 289  * calculations etc. Now we should just copy the data from user
 290  * space and write it back to the real medium..
 291  *
 292  * If the writer ends up delaying the write, the writer needs to
 293  * increment the page use counts until he is done with the page.
 294  */
 295 static int smb_write_begin(struct file *file, struct address_space *mapping,
 296                         loff_t pos, unsigned len, unsigned flags,
 297                         struct page **pagep, void **fsdata)
 298 {
 299         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 300         *pagep = __grab_cache_page(mapping, index);
 301         if (!*pagep)
 302                 return -ENOMEM;
 303         return 0;
 304 }
 305
 306 static int smb_write_end(struct file *file, struct address_space *mapping,
 307                         loff_t pos, unsigned len, unsigned copied,
 308                         struct page *page, void *fsdata)
 309 {
 310         int status;
 311         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 312
 313         lock_kernel();
 314         status = smb_updatepage(file, page, offset, copied);
 315         unlock_kernel();
 316
 317         if (!status) {
 318                 if (!PageUptodate(page) && copied == PAGE_CACHE_SIZE)
 319                         SetPageUptodate(page);
 320                 status = copied;
 321         }
 322
 323         unlock_page(page);
 324         page_cache_release(page);
 325
 326         return status;
 327 }
 328
 329 const struct address_space_operations smb_file_aops = {
 330         .readpage = smb_readpage,
 331         .writepage = smb_writepage,
 332         .write_begin = smb_write_begin,
 333         .write_end = smb_write_end,
 334 };
 335
 336 /*
 337  * Write to a file (through the page cache).
 338  */
 339 static ssize_t
 340 smb_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 341                                unsigned long nr_segs, loff_t pos)
 342 {
 343         struct file * file = iocb->ki_filp;
 344         struct dentry * dentry = file->f_path.dentry;
 345         ssize_t result;
 346
 347         VERBOSE("file %s/%s, count=%lu@%lu\n",
 348                 DENTRY_PATH(dentry),
 349                 (unsigned long) iocb->ki_left, (unsigned long) pos);
 350
 351         result = smb_revalidate_inode(dentry);
 352         if (result) {
 353                 PARANOIA("%s/%s validation failed, error=%Zd\n",
 354                          DENTRY_PATH(dentry), result);
 355                 goto out;
 356         }
 357
 358         result = smb_open(dentry, SMB_O_WRONLY);
 359         if (result)
 360                 goto out;
 361
 362         if (iocb->ki_left > 0) {
 363                 result = generic_file_aio_write(iocb, iov, nr_segs, pos);
 364                 VERBOSE("pos=%ld, size=%ld, mtime=%ld, atime=%ld\n",
 365                         (long) file->f_pos, (long) dentry->d_inode->i_size,
 366                         dentry->d_inode->i_mtime.tv_sec,
 367                         dentry->d_inode->i_atime.tv_sec);
 368         }
 369 out:
 370         return result;
 371 }
 372
 373 static int
 374 smb_file_open(struct inode *inode, struct file * file)
 375 {
 376         int result;
 377         struct dentry *dentry = file->f_path.dentry;
 378         int smb_mode = (file->f_mode & O_ACCMODE) - 1;
 379
 380         lock_kernel();
 381         result = smb_open(dentry, smb_mode);
 382         if (result)
 383                 goto out;
 384         SMB_I(inode)->openers++;
 385 out:
 386         unlock_kernel();
 387         return result;
 388 }
 389
 390 static int
 391 smb_file_release(struct inode *inode, struct file * file)
 392 {
 393         lock_kernel();
 394         if (!--SMB_I(inode)->openers) {
 395                 /* We must flush any dirty pages now as we won't be able to
 396                    write anything after close. mmap can trigger this.
 397                    "openers" should perhaps include mmap'ers ... */
 398                 filemap_write_and_wait(inode->i_mapping);
 399                 smb_close(inode);
 400         }
 401         unlock_kernel();
 402         return 0;
 403 }
 404
 405 /*
 406  * Check whether the required access is compatible with
 407  * an inode's permission. SMB doesn't recognize superuser
 408  * privileges, so we need our own check for this.
 409  */
 410 static int
 411 smb_file_permission(struct inode *inode, int mask, struct nameidata *nd)
 412 {
 413         int mode = inode->i_mode;
 414         int error = 0;
 415
 416         VERBOSE("mode=%x, mask=%x\n", mode, mask);
 417
 418         /* Look at user permissions */
 419         mode >>= 6;
 420         if ((mode & 7 & mask) != mask)
 421                 error = -EACCES;
 422         return error;
 423 }
 424
 425 const struct file_operations smb_file_operations =
 426 {
 427         .llseek         = remote_llseek,
 428         .read           = do_sync_read,
 429         .aio_read       = smb_file_aio_read,
 430         .write          = do_sync_write,
 431         .aio_write      = smb_file_aio_write,
 432         .ioctl          = smb_ioctl,
 433         .mmap           = smb_file_mmap,
 434         .open           = smb_file_open,
 435         .release        = smb_file_release,
 436         .fsync          = smb_fsync,
 437         .splice_read    = smb_file_splice_read,
 438 };
 439
 440 const struct inode_operations smb_file_inode_operations =
 441 {
 442         .permission     = smb_file_permission,
 443         .getattr        = smb_getattr,
 444         .setattr        = smb_notify_change,
 445 };