linux/fs/smbfs/file.c
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   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
  31static int
  32smb_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 */
  54static int
  55smb_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
  93io_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 */
 102static int
 103smb_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 */
 118static int
 119smb_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 */
 173static int
 174smb_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 */
 196do_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
 205static int
 206smb_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
 217static ssize_t
 218smb_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);
 240out:
 241        return status;
 242}
 243
 244static int
 245smb_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);
 260out:
 261        return status;
 262}
 263
 264static ssize_t
 265smb_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);
 282out:
 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 */
 295static 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_write_begin(mapping, index, flags);
 301        if (!*pagep)
 302                return -ENOMEM;
 303        return 0;
 304}
 305
 306static 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
 329const 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 */
 339static ssize_t
 340smb_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        }
 369out:
 370        return result;
 371}
 372
 373static int
 374smb_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++;
 385out:
 386        unlock_kernel();
 387        return result;
 388}
 389
 390static int
 391smb_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 */
 410static int
 411smb_file_permission(struct inode *inode, int mask)
 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 (mask & ~mode & (MAY_READ | MAY_WRITE | MAY_EXEC))
 421                error = -EACCES;
 422        return error;
 423}
 424
 425static loff_t smb_remote_llseek(struct file *file, loff_t offset, int origin)
 426{
 427        loff_t ret;
 428        lock_kernel();
 429        ret = generic_file_llseek_unlocked(file, offset, origin);
 430        unlock_kernel();
 431        return ret;
 432}
 433
 434const struct file_operations smb_file_operations =
 435{
 436        .llseek         = smb_remote_llseek,
 437        .read           = do_sync_read,
 438        .aio_read       = smb_file_aio_read,
 439        .write          = do_sync_write,
 440        .aio_write      = smb_file_aio_write,
 441        .ioctl          = smb_ioctl,
 442        .mmap           = smb_file_mmap,
 443        .open           = smb_file_open,
 444        .release        = smb_file_release,
 445        .fsync          = smb_fsync,
 446        .splice_read    = smb_file_splice_read,
 447};
 448
 449const struct inode_operations smb_file_inode_operations =
 450{
 451        .permission     = smb_file_permission,
 452        .getattr        = smb_getattr,
 453        .setattr        = smb_notify_change,
 454};
 455