fs/reiserfs/file.c

   1 /*
   2  * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
   3  */
   4
   5 #include <linux/time.h>
   6 #include <linux/reiserfs_fs.h>
   7 #include <linux/reiserfs_acl.h>
   8 #include <linux/reiserfs_xattr.h>
   9 #include <asm/uaccess.h>
  10 #include <linux/pagemap.h>
  11 #include <linux/swap.h>
  12 #include <linux/writeback.h>
  13 #include <linux/blkdev.h>
  14 #include <linux/buffer_head.h>
  15 #include <linux/quotaops.h>
  16
  17 /*
  18 ** We pack the tails of files on file close, not at the time they are written.
  19 ** This implies an unnecessary copy of the tail and an unnecessary indirect item
  20 ** insertion/balancing, for files that are written in one write.
  21 ** It avoids unnecessary tail packings (balances) for files that are written in
  22 ** multiple writes and are small enough to have tails.
  23 **
  24 ** file_release is called by the VFS layer when the file is closed.  If
  25 ** this is the last open file descriptor, and the file
  26 ** small enough to have a tail, and the tail is currently in an
  27 ** unformatted node, the tail is converted back into a direct item.
  28 **
  29 ** We use reiserfs_truncate_file to pack the tail, since it already has
  30 ** all the conditions coded.
  31 */
  32 static int reiserfs_file_release(struct inode *inode, struct file *filp)
  33 {
  34
  35         struct reiserfs_transaction_handle th;
  36         int err;
  37         int jbegin_failure = 0;
  38
  39         BUG_ON(!S_ISREG(inode->i_mode));
  40
  41         if (atomic_add_unless(&REISERFS_I(inode)->openers, -1, 1))
  42                 return 0;
  43
  44         mutex_lock(&(REISERFS_I(inode)->tailpack));
  45
  46         if (!atomic_dec_and_test(&REISERFS_I(inode)->openers)) {
  47                 mutex_unlock(&(REISERFS_I(inode)->tailpack));
  48                 return 0;
  49         }
  50
  51         /* fast out for when nothing needs to be done */
  52         if ((!(REISERFS_I(inode)->i_flags & i_pack_on_close_mask) ||
  53              !tail_has_to_be_packed(inode)) &&
  54             REISERFS_I(inode)->i_prealloc_count <= 0) {
  55                 mutex_unlock(&(REISERFS_I(inode)->tailpack));
  56                 return 0;
  57         }
  58
  59         reiserfs_write_lock(inode->i_sb);
  60         /* freeing preallocation only involves relogging blocks that
  61          * are already in the current transaction.  preallocation gets
  62          * freed at the end of each transaction, so it is impossible for
  63          * us to log any additional blocks (including quota blocks)
  64          */
  65         err = journal_begin(&th, inode->i_sb, 1);
  66         if (err) {
  67                 /* uh oh, we can't allow the inode to go away while there
  68                  * is still preallocation blocks pending.  Try to join the
  69                  * aborted transaction
  70                  */
  71                 jbegin_failure = err;
  72                 err = journal_join_abort(&th, inode->i_sb, 1);
  73
  74                 if (err) {
  75                         /* hmpf, our choices here aren't good.  We can pin the inode
  76                          * which will disallow unmount from every happening, we can
  77                          * do nothing, which will corrupt random memory on unmount,
  78                          * or we can forcibly remove the file from the preallocation
  79                          * list, which will leak blocks on disk.  Lets pin the inode
  80                          * and let the admin know what is going on.
  81                          */
  82                         igrab(inode);
  83                         reiserfs_warning(inode->i_sb, "clm-9001",
  84                                          "pinning inode %lu because the "
  85                                          "preallocation can't be freed",
  86                                          inode->i_ino);
  87                         goto out;
  88                 }
  89         }
  90         reiserfs_update_inode_transaction(inode);
  91
  92 #ifdef REISERFS_PREALLOCATE
  93         reiserfs_discard_prealloc(&th, inode);
  94 #endif
  95         err = journal_end(&th, inode->i_sb, 1);
  96
  97         /* copy back the error code from journal_begin */
  98         if (!err)
  99                 err = jbegin_failure;
 100
 101         if (!err &&
 102             (REISERFS_I(inode)->i_flags & i_pack_on_close_mask) &&
 103             tail_has_to_be_packed(inode)) {
 104
 105                 /* if regular file is released by last holder and it has been
 106                    appended (we append by unformatted node only) or its direct
 107                    item(s) had to be converted, then it may have to be
 108                    indirect2direct converted */
 109                 err = reiserfs_truncate_file(inode, 0);
 110         }
 111       out:
 112         reiserfs_write_unlock(inode->i_sb);
 113         mutex_unlock(&(REISERFS_I(inode)->tailpack));
 114         return err;
 115 }
 116
 117 static int reiserfs_file_open(struct inode *inode, struct file *file)
 118 {
 119         int err = dquot_file_open(inode, file);
 120         if (!atomic_inc_not_zero(&REISERFS_I(inode)->openers)) {
 121                 /* somebody might be tailpacking on final close; wait for it */
 122                 mutex_lock(&(REISERFS_I(inode)->tailpack));
 123                 atomic_inc(&REISERFS_I(inode)->openers);
 124                 mutex_unlock(&(REISERFS_I(inode)->tailpack));
 125         }
 126         return err;
 127 }
 128
 129 static void reiserfs_vfs_truncate_file(struct inode *inode)
 130 {
 131         mutex_lock(&(REISERFS_I(inode)->tailpack));
 132         reiserfs_truncate_file(inode, 1);
 133         mutex_unlock(&(REISERFS_I(inode)->tailpack));
 134 }
 135
 136 /* Sync a reiserfs file. */
 137
 138 /*
 139  * FIXME: sync_mapping_buffers() never has anything to sync.  Can
 140  * be removed...
 141  */
 142
 143 static int reiserfs_sync_file(struct file *filp, loff_t start, loff_t end,
 144                               int datasync)
 145 {
 146         struct inode *inode = filp->f_mapping->host;
 147         int err;
 148         int barrier_done;
 149
 150         err = filemap_write_and_wait_range(inode->i_mapping, start, end);
 151         if (err)
 152                 return err;
 153
 154         mutex_lock(&inode->i_mutex);
 155         BUG_ON(!S_ISREG(inode->i_mode));
 156         err = sync_mapping_buffers(inode->i_mapping);
 157         reiserfs_write_lock(inode->i_sb);
 158         barrier_done = reiserfs_commit_for_inode(inode);
 159         reiserfs_write_unlock(inode->i_sb);
 160         if (barrier_done != 1 && reiserfs_barrier_flush(inode->i_sb))
 161                 blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
 162         mutex_unlock(&inode->i_mutex);
 163         if (barrier_done < 0)
 164                 return barrier_done;
 165         return (err < 0) ? -EIO : 0;
 166 }
 167
 168 /* taken fs/buffer.c:__block_commit_write */
 169 int reiserfs_commit_page(struct inode *inode, struct page *page,
 170                          unsigned from, unsigned to)
 171 {
 172         unsigned block_start, block_end;
 173         int partial = 0;
 174         unsigned blocksize;
 175         struct buffer_head *bh, *head;
 176         unsigned long i_size_index = inode->i_size >> PAGE_CACHE_SHIFT;
 177         int new;
 178         int logit = reiserfs_file_data_log(inode);
 179         struct super_block *s = inode->i_sb;
 180         int bh_per_page = PAGE_CACHE_SIZE / s->s_blocksize;
 181         struct reiserfs_transaction_handle th;
 182         int ret = 0;
 183
 184         th.t_trans_id = 0;
 185         blocksize = 1 << inode->i_blkbits;
 186
 187         if (logit) {
 188                 reiserfs_write_lock(s);
 189                 ret = journal_begin(&th, s, bh_per_page + 1);
 190                 if (ret)
 191                         goto drop_write_lock;
 192                 reiserfs_update_inode_transaction(inode);
 193         }
 194         for (bh = head = page_buffers(page), block_start = 0;
 195              bh != head || !block_start;
 196              block_start = block_end, bh = bh->b_this_page) {
 197
 198                 new = buffer_new(bh);
 199                 clear_buffer_new(bh);
 200                 block_end = block_start + blocksize;
 201                 if (block_end <= from || block_start >= to) {
 202                         if (!buffer_uptodate(bh))
 203                                 partial = 1;
 204                 } else {
 205                         set_buffer_uptodate(bh);
 206                         if (logit) {
 207                                 reiserfs_prepare_for_journal(s, bh, 1);
 208                                 journal_mark_dirty(&th, s, bh);
 209                         } else if (!buffer_dirty(bh)) {
 210                                 mark_buffer_dirty(bh);
 211                                 /* do data=ordered on any page past the end
 212                                  * of file and any buffer marked BH_New.
 213                                  */
 214                                 if (reiserfs_data_ordered(inode->i_sb) &&
 215                                     (new || page->index >= i_size_index)) {
 216                                         reiserfs_add_ordered_list(inode, bh);
 217                                 }
 218                         }
 219                 }
 220         }
 221         if (logit) {
 222                 ret = journal_end(&th, s, bh_per_page + 1);
 223               drop_write_lock:
 224                 reiserfs_write_unlock(s);
 225         }
 226         /*
 227          * If this is a partial write which happened to make all buffers
 228          * uptodate then we can optimize away a bogus readpage() for
 229          * the next read(). Here we 'discover' whether the page went
 230          * uptodate as a result of this (potentially partial) write.
 231          */
 232         if (!partial)
 233                 SetPageUptodate(page);
 234         return ret;
 235 }
 236
 237 /* Write @count bytes at position @ppos in a file indicated by @file
 238    from the buffer @buf.
 239
 240    generic_file_write() is only appropriate for filesystems that are not seeking to optimize performance and want
 241    something simple that works.  It is not for serious use by general purpose filesystems, excepting the one that it was
 242    written for (ext2/3).  This is for several reasons:
 243
 244    * It has no understanding of any filesystem specific optimizations.
 245
 246    * It enters the filesystem repeatedly for each page that is written.
 247
 248    * It depends on reiserfs_get_block() function which if implemented by reiserfs performs costly search_by_key
 249    * operation for each page it is supplied with. By contrast reiserfs_file_write() feeds as much as possible at a time
 250    * to reiserfs which allows for fewer tree traversals.
 251
 252    * Each indirect pointer insertion takes a lot of cpu, because it involves memory moves inside of blocks.
 253
 254    * Asking the block allocation code for blocks one at a time is slightly less efficient.
 255
 256    All of these reasons for not using only generic file write were understood back when reiserfs was first miscoded to
 257    use it, but we were in a hurry to make code freeze, and so it couldn't be revised then.  This new code should make
 258    things right finally.
 259
 260    Future Features: providing search_by_key with hints.
 261
 262 */
 263 static ssize_t reiserfs_file_write(struct file *file,   /* the file we are going to write into */
 264                                    const char __user * buf,     /*  pointer to user supplied data
 265                                                                    (in userspace) */
 266                                    size_t count,        /* amount of bytes to write */
 267                                    loff_t * ppos        /* pointer to position in file that we start writing at. Should be updated to
 268                                                          * new current position before returning. */
 269                                    )
 270 {
 271         struct inode *inode = file->f_path.dentry->d_inode;     // Inode of the file that we are writing to.
 272         /* To simplify coding at this time, we store
 273            locked pages in array for now */
 274         struct reiserfs_transaction_handle th;
 275         th.t_trans_id = 0;
 276
 277         /* If a filesystem is converted from 3.5 to 3.6, we'll have v3.5 items
 278         * lying around (most of the disk, in fact). Despite the filesystem
 279         * now being a v3.6 format, the old items still can't support large
 280         * file sizes. Catch this case here, as the rest of the VFS layer is
 281         * oblivious to the different limitations between old and new items.
 282         * reiserfs_setattr catches this for truncates. This chunk is lifted
 283         * from generic_write_checks. */
 284         if (get_inode_item_key_version (inode) == KEY_FORMAT_3_5 &&
 285             *ppos + count > MAX_NON_LFS) {
 286                 if (*ppos >= MAX_NON_LFS) {
 287                         return -EFBIG;
 288                 }
 289                 if (count > MAX_NON_LFS - (unsigned long)*ppos)
 290                         count = MAX_NON_LFS - (unsigned long)*ppos;
 291         }
 292
 293         return do_sync_write(file, buf, count, ppos);
 294 }
 295
 296 const struct file_operations reiserfs_file_operations = {
 297         .read = do_sync_read,
 298         .write = reiserfs_file_write,
 299         .unlocked_ioctl = reiserfs_ioctl,
 300 #ifdef CONFIG_COMPAT
 301         .compat_ioctl = reiserfs_compat_ioctl,
 302 #endif
 303         .mmap = generic_file_mmap,
 304         .open = reiserfs_file_open,
 305         .release = reiserfs_file_release,
 306         .fsync = reiserfs_sync_file,
 307         .aio_read = generic_file_aio_read,
 308         .aio_write = generic_file_aio_write,
 309         .splice_read = generic_file_splice_read,
 310         .splice_write = generic_file_splice_write,
 311         .llseek = generic_file_llseek,
 312 };
 313
 314 const struct inode_operations reiserfs_file_inode_operations = {
 315         .truncate = reiserfs_vfs_truncate_file,
 316         .setattr = reiserfs_setattr,
 317         .setxattr = reiserfs_setxattr,
 318         .getxattr = reiserfs_getxattr,
 319         .listxattr = reiserfs_listxattr,
 320         .removexattr = reiserfs_removexattr,
 321         .permission = reiserfs_permission,
 322         .check_acl = reiserfs_check_acl,
 323 };