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, int datasync)
 144 {
 145         struct inode *inode = filp->f_mapping->host;
 146         int err;
 147         int barrier_done;
 148
 149         BUG_ON(!S_ISREG(inode->i_mode));
 150         err = sync_mapping_buffers(inode->i_mapping);
 151         reiserfs_write_lock(inode->i_sb);
 152         barrier_done = reiserfs_commit_for_inode(inode);
 153         reiserfs_write_unlock(inode->i_sb);
 154         if (barrier_done != 1 && reiserfs_barrier_flush(inode->i_sb))
 155                 blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL,
 156                         BLKDEV_IFL_WAIT);
 157         if (barrier_done < 0)
 158                 return barrier_done;
 159         return (err < 0) ? -EIO : 0;
 160 }
 161
 162 /* taken fs/buffer.c:__block_commit_write */
 163 int reiserfs_commit_page(struct inode *inode, struct page *page,
 164                          unsigned from, unsigned to)
 165 {
 166         unsigned block_start, block_end;
 167         int partial = 0;
 168         unsigned blocksize;
 169         struct buffer_head *bh, *head;
 170         unsigned long i_size_index = inode->i_size >> PAGE_CACHE_SHIFT;
 171         int new;
 172         int logit = reiserfs_file_data_log(inode);
 173         struct super_block *s = inode->i_sb;
 174         int bh_per_page = PAGE_CACHE_SIZE / s->s_blocksize;
 175         struct reiserfs_transaction_handle th;
 176         int ret = 0;
 177
 178         th.t_trans_id = 0;
 179         blocksize = 1 << inode->i_blkbits;
 180
 181         if (logit) {
 182                 reiserfs_write_lock(s);
 183                 ret = journal_begin(&th, s, bh_per_page + 1);
 184                 if (ret)
 185                         goto drop_write_lock;
 186                 reiserfs_update_inode_transaction(inode);
 187         }
 188         for (bh = head = page_buffers(page), block_start = 0;
 189              bh != head || !block_start;
 190              block_start = block_end, bh = bh->b_this_page) {
 191
 192                 new = buffer_new(bh);
 193                 clear_buffer_new(bh);
 194                 block_end = block_start + blocksize;
 195                 if (block_end <= from || block_start >= to) {
 196                         if (!buffer_uptodate(bh))
 197                                 partial = 1;
 198                 } else {
 199                         set_buffer_uptodate(bh);
 200                         if (logit) {
 201                                 reiserfs_prepare_for_journal(s, bh, 1);
 202                                 journal_mark_dirty(&th, s, bh);
 203                         } else if (!buffer_dirty(bh)) {
 204                                 mark_buffer_dirty(bh);
 205                                 /* do data=ordered on any page past the end
 206                                  * of file and any buffer marked BH_New.
 207                                  */
 208                                 if (reiserfs_data_ordered(inode->i_sb) &&
 209                                     (new || page->index >= i_size_index)) {
 210                                         reiserfs_add_ordered_list(inode, bh);
 211                                 }
 212                         }
 213                 }
 214         }
 215         if (logit) {
 216                 ret = journal_end(&th, s, bh_per_page + 1);
 217               drop_write_lock:
 218                 reiserfs_write_unlock(s);
 219         }
 220         /*
 221          * If this is a partial write which happened to make all buffers
 222          * uptodate then we can optimize away a bogus readpage() for
 223          * the next read(). Here we 'discover' whether the page went
 224          * uptodate as a result of this (potentially partial) write.
 225          */
 226         if (!partial)
 227                 SetPageUptodate(page);
 228         return ret;
 229 }
 230
 231 /* Write @count bytes at position @ppos in a file indicated by @file
 232    from the buffer @buf.
 233
 234    generic_file_write() is only appropriate for filesystems that are not seeking to optimize performance and want
 235    something simple that works.  It is not for serious use by general purpose filesystems, excepting the one that it was
 236    written for (ext2/3).  This is for several reasons:
 237
 238    * It has no understanding of any filesystem specific optimizations.
 239
 240    * It enters the filesystem repeatedly for each page that is written.
 241
 242    * It depends on reiserfs_get_block() function which if implemented by reiserfs performs costly search_by_key
 243    * operation for each page it is supplied with. By contrast reiserfs_file_write() feeds as much as possible at a time
 244    * to reiserfs which allows for fewer tree traversals.
 245
 246    * Each indirect pointer insertion takes a lot of cpu, because it involves memory moves inside of blocks.
 247
 248    * Asking the block allocation code for blocks one at a time is slightly less efficient.
 249
 250    All of these reasons for not using only generic file write were understood back when reiserfs was first miscoded to
 251    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
 252    things right finally.
 253
 254    Future Features: providing search_by_key with hints.
 255
 256 */
 257 static ssize_t reiserfs_file_write(struct file *file,   /* the file we are going to write into */
 258                                    const char __user * buf,     /*  pointer to user supplied data
 259                                                                    (in userspace) */
 260                                    size_t count,        /* amount of bytes to write */
 261                                    loff_t * ppos        /* pointer to position in file that we start writing at. Should be updated to
 262                                                          * new current position before returning. */
 263                                    )
 264 {
 265         struct inode *inode = file->f_path.dentry->d_inode;     // Inode of the file that we are writing to.
 266         /* To simplify coding at this time, we store
 267            locked pages in array for now */
 268         struct reiserfs_transaction_handle th;
 269         th.t_trans_id = 0;
 270
 271         /* If a filesystem is converted from 3.5 to 3.6, we'll have v3.5 items
 272         * lying around (most of the disk, in fact). Despite the filesystem
 273         * now being a v3.6 format, the old items still can't support large
 274         * file sizes. Catch this case here, as the rest of the VFS layer is
 275         * oblivious to the different limitations between old and new items.
 276         * reiserfs_setattr catches this for truncates. This chunk is lifted
 277         * from generic_write_checks. */
 278         if (get_inode_item_key_version (inode) == KEY_FORMAT_3_5 &&
 279             *ppos + count > MAX_NON_LFS) {
 280                 if (*ppos >= MAX_NON_LFS) {
 281                         return -EFBIG;
 282                 }
 283                 if (count > MAX_NON_LFS - (unsigned long)*ppos)
 284                         count = MAX_NON_LFS - (unsigned long)*ppos;
 285         }
 286
 287         return do_sync_write(file, buf, count, ppos);
 288 }
 289
 290 const struct file_operations reiserfs_file_operations = {
 291         .read = do_sync_read,
 292         .write = reiserfs_file_write,
 293         .unlocked_ioctl = reiserfs_ioctl,
 294 #ifdef CONFIG_COMPAT
 295         .compat_ioctl = reiserfs_compat_ioctl,
 296 #endif
 297         .mmap = generic_file_mmap,
 298         .open = reiserfs_file_open,
 299         .release = reiserfs_file_release,
 300         .fsync = reiserfs_sync_file,
 301         .aio_read = generic_file_aio_read,
 302         .aio_write = generic_file_aio_write,
 303         .splice_read = generic_file_splice_read,
 304         .splice_write = generic_file_splice_write,
 305         .llseek = generic_file_llseek,
 306 };
 307
 308 const struct inode_operations reiserfs_file_inode_operations = {
 309         .truncate = reiserfs_vfs_truncate_file,
 310         .setattr = reiserfs_setattr,
 311         .setxattr = reiserfs_setxattr,
 312         .getxattr = reiserfs_getxattr,
 313         .listxattr = reiserfs_listxattr,
 314         .removexattr = reiserfs_removexattr,
 315         .permission = reiserfs_permission,
 316 };