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