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 "reiserfs.h"
   7 #include "acl.h"
   8 #include "xattr.h"
   9 #include <linux/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         /*
  61          * freeing preallocation only involves relogging blocks that
  62          * are already in the current transaction.  preallocation gets
  63          * freed at the end of each transaction, so it is impossible for
  64          * us to log any additional blocks (including quota blocks)
  65          */
  66         err = journal_begin(&th, inode->i_sb, 1);
  67         if (err) {
  68                 /*
  69                  * uh oh, we can't allow the inode to go away while there
  70                  * is still preallocation blocks pending.  Try to join the
  71                  * aborted transaction
  72                  */
  73                 jbegin_failure = err;
  74                 err = journal_join_abort(&th, inode->i_sb);
  75
  76                 if (err) {
  77                         /*
  78                          * hmpf, our choices here aren't good.  We can pin
  79                          * the inode which will disallow unmount from ever
  80                          * happening, we can do nothing, which will corrupt
  81                          * random memory on unmount, or we can forcibly
  82                          * remove the file from the preallocation list, which
  83                          * will leak blocks on disk.  Lets pin the inode
  84                          * and let the admin know what is going on.
  85                          */
  86                         igrab(inode);
  87                         reiserfs_warning(inode->i_sb, "clm-9001",
  88                                          "pinning inode %lu because the "
  89                                          "preallocation can't be freed",
  90                                          inode->i_ino);
  91                         goto out;
  92                 }
  93         }
  94         reiserfs_update_inode_transaction(inode);
  95
  96 #ifdef REISERFS_PREALLOCATE
  97         reiserfs_discard_prealloc(&th, inode);
  98 #endif
  99         err = journal_end(&th);
 100
 101         /* copy back the error code from journal_begin */
 102         if (!err)
 103                 err = jbegin_failure;
 104
 105         if (!err &&
 106             (REISERFS_I(inode)->i_flags & i_pack_on_close_mask) &&
 107             tail_has_to_be_packed(inode)) {
 108
 109                 /*
 110                  * if regular file is released by last holder and it has been
 111                  * appended (we append by unformatted node only) or its direct
 112                  * item(s) had to be converted, then it may have to be
 113                  * indirect2direct converted
 114                  */
 115                 err = reiserfs_truncate_file(inode, 0);
 116         }
 117 out:
 118         reiserfs_write_unlock(inode->i_sb);
 119         mutex_unlock(&REISERFS_I(inode)->tailpack);
 120         return err;
 121 }
 122
 123 static int reiserfs_file_open(struct inode *inode, struct file *file)
 124 {
 125         int err = dquot_file_open(inode, file);
 126
 127         /* somebody might be tailpacking on final close; wait for it */
 128         if (!atomic_inc_not_zero(&REISERFS_I(inode)->openers)) {
 129                 mutex_lock(&REISERFS_I(inode)->tailpack);
 130                 atomic_inc(&REISERFS_I(inode)->openers);
 131                 mutex_unlock(&REISERFS_I(inode)->tailpack);
 132         }
 133         return err;
 134 }
 135
 136 void reiserfs_vfs_truncate_file(struct inode *inode)
 137 {
 138         mutex_lock(&REISERFS_I(inode)->tailpack);
 139         reiserfs_truncate_file(inode, 1);
 140         mutex_unlock(&REISERFS_I(inode)->tailpack);
 141 }
 142
 143 /* Sync a reiserfs file. */
 144
 145 /*
 146  * FIXME: sync_mapping_buffers() never has anything to sync.  Can
 147  * be removed...
 148  */
 149
 150 static int reiserfs_sync_file(struct file *filp, loff_t start, loff_t end,
 151                               int datasync)
 152 {
 153         struct inode *inode = filp->f_mapping->host;
 154         int err;
 155         int barrier_done;
 156
 157         err = file_write_and_wait_range(filp, start, end);
 158         if (err)
 159                 return err;
 160
 161         inode_lock(inode);
 162         BUG_ON(!S_ISREG(inode->i_mode));
 163         err = sync_mapping_buffers(inode->i_mapping);
 164         reiserfs_write_lock(inode->i_sb);
 165         barrier_done = reiserfs_commit_for_inode(inode);
 166         reiserfs_write_unlock(inode->i_sb);
 167         if (barrier_done != 1 && reiserfs_barrier_flush(inode->i_sb))
 168                 blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
 169         inode_unlock(inode);
 170         if (barrier_done < 0)
 171                 return barrier_done;
 172         return (err < 0) ? -EIO : 0;
 173 }
 174
 175 /* taken fs/buffer.c:__block_commit_write */
 176 int reiserfs_commit_page(struct inode *inode, struct page *page,
 177                          unsigned from, unsigned to)
 178 {
 179         unsigned block_start, block_end;
 180         int partial = 0;
 181         unsigned blocksize;
 182         struct buffer_head *bh, *head;
 183         unsigned long i_size_index = inode->i_size >> PAGE_SHIFT;
 184         int new;
 185         int logit = reiserfs_file_data_log(inode);
 186         struct super_block *s = inode->i_sb;
 187         int bh_per_page = PAGE_SIZE / s->s_blocksize;
 188         struct reiserfs_transaction_handle th;
 189         int ret = 0;
 190
 191         th.t_trans_id = 0;
 192         blocksize = i_blocksize(inode);
 193
 194         if (logit) {
 195                 reiserfs_write_lock(s);
 196                 ret = journal_begin(&th, s, bh_per_page + 1);
 197                 if (ret)
 198                         goto drop_write_lock;
 199                 reiserfs_update_inode_transaction(inode);
 200         }
 201         for (bh = head = page_buffers(page), block_start = 0;
 202              bh != head || !block_start;
 203              block_start = block_end, bh = bh->b_this_page) {
 204
 205                 new = buffer_new(bh);
 206                 clear_buffer_new(bh);
 207                 block_end = block_start + blocksize;
 208                 if (block_end <= from || block_start >= to) {
 209                         if (!buffer_uptodate(bh))
 210                                 partial = 1;
 211                 } else {
 212                         set_buffer_uptodate(bh);
 213                         if (logit) {
 214                                 reiserfs_prepare_for_journal(s, bh, 1);
 215                                 journal_mark_dirty(&th, bh);
 216                         } else if (!buffer_dirty(bh)) {
 217                                 mark_buffer_dirty(bh);
 218                                 /*
 219                                  * do data=ordered on any page past the end
 220                                  * of file and any buffer marked BH_New.
 221                                  */
 222                                 if (reiserfs_data_ordered(inode->i_sb) &&
 223                                     (new || page->index >= i_size_index)) {
 224                                         reiserfs_add_ordered_list(inode, bh);
 225                                 }
 226                         }
 227                 }
 228         }
 229         if (logit) {
 230                 ret = journal_end(&th);
 231 drop_write_lock:
 232                 reiserfs_write_unlock(s);
 233         }
 234         /*
 235          * If this is a partial write which happened to make all buffers
 236          * uptodate then we can optimize away a bogus readpage() for
 237          * the next read(). Here we 'discover' whether the page went
 238          * uptodate as a result of this (potentially partial) write.
 239          */
 240         if (!partial)
 241                 SetPageUptodate(page);
 242         return ret;
 243 }
 244
 245 const struct file_operations reiserfs_file_operations = {
 246         .unlocked_ioctl = reiserfs_ioctl,
 247 #ifdef CONFIG_COMPAT
 248         .compat_ioctl = reiserfs_compat_ioctl,
 249 #endif
 250         .mmap = generic_file_mmap,
 251         .open = reiserfs_file_open,
 252         .release = reiserfs_file_release,
 253         .fsync = reiserfs_sync_file,
 254         .read_iter = generic_file_read_iter,
 255         .write_iter = generic_file_write_iter,
 256         .splice_read = generic_file_splice_read,
 257         .splice_write = iter_file_splice_write,
 258         .llseek = generic_file_llseek,
 259 };
 260
 261 const struct inode_operations reiserfs_file_inode_operations = {
 262         .setattr = reiserfs_setattr,
 263         .listxattr = reiserfs_listxattr,
 264         .permission = reiserfs_permission,
 265         .get_acl = reiserfs_get_acl,
 266         .set_acl = reiserfs_set_acl,
 267 };