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                 PARANOIA("%s/%s open failed, error=%d\n",
  53                          DENTRY_PATH(dentry), result);
  54                 goto io_error;
  55         }
  56
  57         do {
  58                 if (count < rsize)
  59                         rsize = count;
  60
  61                 result = smb_proc_read(dentry->d_inode, offset, rsize, buffer);
  62                 if (result < 0)
  63                         goto io_error;
  64
  65                 count -= result;
  66                 offset += result;
  67                 buffer += result;
  68                 dentry->d_inode->i_atime = CURRENT_TIME;
  69                 if (result < rsize)
  70                         break;
  71         } while (count);
  72
  73         memset(buffer, 0, count);
  74         flush_dcache_page(page);
  75         SetPageUptodate(page);
  76         result = 0;
  77
  78 io_error:
  79         UnlockPage(page);
  80         return result;
  81 }
  82
  83 /*
  84  * We are called with the page locked and we unlock it when done.
  85  */
  86 static int
  87 smb_readpage(struct file *file, struct page *page)
  88 {
  89         int             error;
  90         struct dentry  *dentry = file->f_dentry;
  91
  92         DEBUG1("readpage %p\n", page_address(page));
  93
  94         get_page(page);
  95         error = smb_readpage_sync(dentry, page);
  96         put_page(page);
  97         return error;
  98 }
  99
 100 /*
 101  * Write a page synchronously.
 102  * Offset is the data offset within the page.
 103  */
 104 static int
 105 smb_writepage_sync(struct inode *inode, struct page *page,
 106                    unsigned long offset, unsigned int count)
 107 {
 108         u8 *buffer = page_address(page) + offset;
 109         int wsize = smb_get_wsize(server_from_inode(inode));
 110         int result, written = 0;
 111
 112         offset += page->index << PAGE_CACHE_SHIFT;
 113         VERBOSE("file ino=%ld, fileid=%d, count=%d@%ld, wsize=%d\n",
 114                 inode->i_ino, inode->u.smbfs_i.fileid, count, offset, wsize);
 115
 116         do {
 117                 if (count < wsize)
 118                         wsize = count;
 119
 120                 result = smb_proc_write(inode, offset, wsize, buffer);
 121                 if (result < 0) {
 122                         PARANOIA("failed write, wsize=%d, result=%d\n",
 123                                  wsize, result);
 124                         break;
 125                 }
 126                 /* N.B. what if result < wsize?? */
 127 #ifdef SMBFS_PARANOIA
 128                 if (result < wsize)
 129                         PARANOIA("short write, wsize=%d, result=%d\n",
 130                                  wsize, result);
 131 #endif
 132                 buffer += wsize;
 133                 offset += wsize;
 134                 written += wsize;
 135                 count -= wsize;
 136                 /*
 137                  * Update the inode now rather than waiting for a refresh.
 138                  */
 139                 inode->i_mtime = inode->i_atime = CURRENT_TIME;
 140                 if (offset > inode->i_size)
 141                         inode->i_size = offset;
 142                 inode->u.smbfs_i.cache_valid |= SMB_F_LOCALWRITE;
 143         } while (count);
 144         return written ? written : result;
 145 }
 146
 147 /*
 148  * Write a page to the server. This will be used for NFS swapping only
 149  * (for now), and we currently do this synchronously only.
 150  *
 151  * We are called with the page locked and we unlock it when done.
 152  */
 153 static int
 154 smb_writepage(struct page *page)
 155 {
 156         struct address_space *mapping = page->mapping;
 157         struct inode *inode;
 158         unsigned long end_index;
 159         unsigned offset = PAGE_CACHE_SIZE;
 160         int err;
 161
 162         if (!mapping)
 163                 BUG();
 164         inode = (struct inode *)mapping->host;
 165         if (!inode)
 166                 BUG();
 167
 168         end_index = inode->i_size >> PAGE_CACHE_SHIFT;
 169
 170         /* easy case */
 171         if (page->index < end_index)
 172                 goto do_it;
 173         /* things got complicated... */
 174         offset = inode->i_size & (PAGE_CACHE_SIZE-1);
 175         /* OK, are we completely out? */
 176         if (page->index >= end_index+1 || !offset)
 177                 return -EIO;
 178 do_it:
 179         get_page(page);
 180         err = smb_writepage_sync(inode, page, 0, offset);
 181         SetPageUptodate(page);
 182         UnlockPage(page);
 183         put_page(page);
 184         return err;
 185 }
 186
 187 static int
 188 smb_updatepage(struct file *file, struct page *page, unsigned long offset,
 189                unsigned int count)
 190 {
 191         struct dentry *dentry = file->f_dentry;
 192
 193         DEBUG1("(%s/%s %d@%ld)\n", DENTRY_PATH(dentry),
 194                count, (page->index << PAGE_CACHE_SHIFT)+offset);
 195
 196         return smb_writepage_sync(dentry->d_inode, page, offset, count);
 197 }
 198
 199 static ssize_t
 200 smb_file_read(struct file * file, char * buf, size_t count, loff_t *ppos)
 201 {
 202         struct dentry * dentry = file->f_dentry;
 203         ssize_t status;
 204
 205         VERBOSE("file %s/%s, count=%lu@%lu\n", DENTRY_PATH(dentry),
 206                 (unsigned long) count, (unsigned long) *ppos);
 207
 208         status = smb_revalidate_inode(dentry);
 209         if (status)
 210         {
 211                 PARANOIA("%s/%s validation failed, error=%Zd\n",
 212                          DENTRY_PATH(dentry), status);
 213                 goto out;
 214         }
 215
 216         VERBOSE("before read, size=%ld, flags=%x, atime=%ld\n",
 217                 (long)dentry->d_inode->i_size,
 218                 dentry->d_inode->i_flags, dentry->d_inode->i_atime);
 219
 220         status = generic_file_read(file, buf, count, ppos);
 221 out:
 222         return status;
 223 }
 224
 225 static int
 226 smb_file_mmap(struct file * file, struct vm_area_struct * vma)
 227 {
 228         struct dentry * dentry = file->f_dentry;
 229         int     status;
 230
 231         VERBOSE("file %s/%s, address %lu - %lu\n",
 232                 DENTRY_PATH(dentry), vma->vm_start, vma->vm_end);
 233
 234         status = smb_revalidate_inode(dentry);
 235         if (status)
 236         {
 237                 PARANOIA("%s/%s validation failed, error=%d\n",
 238                          DENTRY_PATH(dentry), status);
 239                 goto out;
 240         }
 241         status = generic_file_mmap(file, vma);
 242 out:
 243         return status;
 244 }
 245
 246 /*
 247  * This does the "real" work of the write. The generic routine has
 248  * allocated the page, locked it, done all the page alignment stuff
 249  * calculations etc. Now we should just copy the data from user
 250  * space and write it back to the real medium..
 251  *
 252  * If the writer ends up delaying the write, the writer needs to
 253  * increment the page use counts until he is done with the page.
 254  */
 255 static int smb_prepare_write(struct file *file, struct page *page,
 256                              unsigned offset, unsigned to)
 257 {
 258         kmap(page);
 259         return 0;
 260 }
 261
 262 static int smb_commit_write(struct file *file, struct page *page,
 263                             unsigned offset, unsigned to)
 264 {
 265         int status;
 266
 267         status = -EFAULT;
 268         lock_kernel();
 269         status = smb_updatepage(file, page, offset, to-offset);
 270         unlock_kernel();
 271         kunmap(page);
 272         return status;
 273 }
 274
 275 struct address_space_operations smb_file_aops = {
 276         readpage: smb_readpage,
 277         writepage: smb_writepage,
 278         prepare_write: smb_prepare_write,
 279         commit_write: smb_commit_write
 280 };
 281
 282 /*
 283  * Write to a file (through the page cache).
 284  */
 285 static ssize_t
 286 smb_file_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
 287 {
 288         struct dentry * dentry = file->f_dentry;
 289         ssize_t result;
 290
 291         VERBOSE("file %s/%s, count=%lu@%lu\n",
 292                 DENTRY_PATH(dentry),
 293                 (unsigned long) count, (unsigned long) *ppos);
 294
 295         result = smb_revalidate_inode(dentry);
 296         if (result)
 297         {
 298                 PARANOIA("%s/%s validation failed, error=%Zd\n",
 299                          DENTRY_PATH(dentry), result);
 300                 goto out;
 301         }
 302
 303         result = smb_open(dentry, SMB_O_WRONLY);
 304         if (result)
 305                 goto out;
 306
 307         if (count > 0)
 308         {
 309                 result = generic_file_write(file, buf, count, ppos);
 310                 VERBOSE("pos=%ld, size=%ld, mtime=%ld, atime=%ld\n",
 311                         (long) file->f_pos, (long) dentry->d_inode->i_size,
 312                         dentry->d_inode->i_mtime, dentry->d_inode->i_atime);
 313         }
 314 out:
 315         return result;
 316 }
 317
 318 static int
 319 smb_file_open(struct inode *inode, struct file * file)
 320 {
 321         int result;
 322         struct dentry *dentry = file->f_dentry;
 323         int smb_mode = (file->f_mode & O_ACCMODE) - 1;
 324
 325         lock_kernel();
 326         result = smb_open(dentry, smb_mode);
 327         if (result)
 328                 goto out;
 329         inode->u.smbfs_i.openers++;
 330 out:
 331         unlock_kernel();
 332         return 0;
 333 }
 334
 335 static int
 336 smb_file_release(struct inode *inode, struct file * file)
 337 {
 338         lock_kernel();
 339         if (!--inode->u.smbfs_i.openers)
 340                 smb_close(inode);
 341         unlock_kernel();
 342         return 0;
 343 }
 344
 345 /*
 346  * Check whether the required access is compatible with
 347  * an inode's permission. SMB doesn't recognize superuser
 348  * privileges, so we need our own check for this.
 349  */
 350 static int
 351 smb_file_permission(struct inode *inode, int mask)
 352 {
 353         int mode = inode->i_mode;
 354         int error = 0;
 355
 356         VERBOSE("mode=%x, mask=%x\n", mode, mask);
 357
 358         /* Look at user permissions */
 359         mode >>= 6;
 360         if ((mode & 7 & mask) != mask)
 361                 error = -EACCES;
 362         return error;
 363 }
 364
 365 struct file_operations smb_file_operations =
 366 {
 367         read:           smb_file_read,
 368         write:          smb_file_write,
 369         ioctl:          smb_ioctl,
 370         mmap:           smb_file_mmap,
 371         open:           smb_file_open,
 372         release:        smb_file_release,
 373         fsync:          smb_fsync,
 374 };
 375
 376 struct inode_operations smb_file_inode_operations =
 377 {
 378         permission:     smb_file_permission,
 379         revalidate:     smb_revalidate_inode,
 380         setattr:        smb_notify_change,
 381 };