mirror of https://gitee.com/openkylin/linux.git
317 lines
10 KiB
C
317 lines
10 KiB
C
/*
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* Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
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*/
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#include <linux/time.h>
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#include <linux/reiserfs_fs.h>
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#include <linux/reiserfs_acl.h>
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#include <linux/reiserfs_xattr.h>
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#include <asm/uaccess.h>
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#include <linux/pagemap.h>
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#include <linux/swap.h>
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#include <linux/writeback.h>
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#include <linux/blkdev.h>
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#include <linux/buffer_head.h>
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#include <linux/quotaops.h>
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/*
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** We pack the tails of files on file close, not at the time they are written.
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** This implies an unnecessary copy of the tail and an unnecessary indirect item
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** insertion/balancing, for files that are written in one write.
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** It avoids unnecessary tail packings (balances) for files that are written in
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** multiple writes and are small enough to have tails.
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**
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** file_release is called by the VFS layer when the file is closed. If
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** this is the last open file descriptor, and the file
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** small enough to have a tail, and the tail is currently in an
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** unformatted node, the tail is converted back into a direct item.
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**
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** We use reiserfs_truncate_file to pack the tail, since it already has
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** all the conditions coded.
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*/
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static int reiserfs_file_release(struct inode *inode, struct file *filp)
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{
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struct reiserfs_transaction_handle th;
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int err;
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int jbegin_failure = 0;
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BUG_ON(!S_ISREG(inode->i_mode));
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if (atomic_add_unless(&REISERFS_I(inode)->openers, -1, 1))
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return 0;
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mutex_lock(&(REISERFS_I(inode)->tailpack));
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if (!atomic_dec_and_test(&REISERFS_I(inode)->openers)) {
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mutex_unlock(&(REISERFS_I(inode)->tailpack));
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return 0;
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}
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/* fast out for when nothing needs to be done */
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if ((!(REISERFS_I(inode)->i_flags & i_pack_on_close_mask) ||
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!tail_has_to_be_packed(inode)) &&
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REISERFS_I(inode)->i_prealloc_count <= 0) {
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mutex_unlock(&(REISERFS_I(inode)->tailpack));
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return 0;
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}
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reiserfs_write_lock(inode->i_sb);
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/* freeing preallocation only involves relogging blocks that
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* are already in the current transaction. preallocation gets
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* freed at the end of each transaction, so it is impossible for
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* us to log any additional blocks (including quota blocks)
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*/
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err = journal_begin(&th, inode->i_sb, 1);
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if (err) {
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/* uh oh, we can't allow the inode to go away while there
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* is still preallocation blocks pending. Try to join the
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* aborted transaction
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*/
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jbegin_failure = err;
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err = journal_join_abort(&th, inode->i_sb, 1);
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if (err) {
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/* hmpf, our choices here aren't good. We can pin the inode
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* which will disallow unmount from every happening, we can
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* do nothing, which will corrupt random memory on unmount,
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* or we can forcibly remove the file from the preallocation
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* list, which will leak blocks on disk. Lets pin the inode
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* and let the admin know what is going on.
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*/
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igrab(inode);
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reiserfs_warning(inode->i_sb, "clm-9001",
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"pinning inode %lu because the "
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"preallocation can't be freed",
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inode->i_ino);
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goto out;
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}
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}
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reiserfs_update_inode_transaction(inode);
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#ifdef REISERFS_PREALLOCATE
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reiserfs_discard_prealloc(&th, inode);
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#endif
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err = journal_end(&th, inode->i_sb, 1);
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/* copy back the error code from journal_begin */
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if (!err)
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err = jbegin_failure;
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if (!err &&
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(REISERFS_I(inode)->i_flags & i_pack_on_close_mask) &&
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tail_has_to_be_packed(inode)) {
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/* if regular file is released by last holder and it has been
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appended (we append by unformatted node only) or its direct
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item(s) had to be converted, then it may have to be
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indirect2direct converted */
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err = reiserfs_truncate_file(inode, 0);
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}
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out:
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reiserfs_write_unlock(inode->i_sb);
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mutex_unlock(&(REISERFS_I(inode)->tailpack));
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return err;
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}
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static int reiserfs_file_open(struct inode *inode, struct file *file)
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{
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int err = dquot_file_open(inode, file);
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if (!atomic_inc_not_zero(&REISERFS_I(inode)->openers)) {
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/* somebody might be tailpacking on final close; wait for it */
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mutex_lock(&(REISERFS_I(inode)->tailpack));
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atomic_inc(&REISERFS_I(inode)->openers);
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mutex_unlock(&(REISERFS_I(inode)->tailpack));
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}
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return err;
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}
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static void reiserfs_vfs_truncate_file(struct inode *inode)
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{
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mutex_lock(&(REISERFS_I(inode)->tailpack));
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reiserfs_truncate_file(inode, 1);
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mutex_unlock(&(REISERFS_I(inode)->tailpack));
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}
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/* Sync a reiserfs file. */
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/*
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* FIXME: sync_mapping_buffers() never has anything to sync. Can
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* be removed...
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*/
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static int reiserfs_sync_file(struct file *filp, int datasync)
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{
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struct inode *inode = filp->f_mapping->host;
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int err;
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int barrier_done;
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BUG_ON(!S_ISREG(inode->i_mode));
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err = sync_mapping_buffers(inode->i_mapping);
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reiserfs_write_lock(inode->i_sb);
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barrier_done = reiserfs_commit_for_inode(inode);
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reiserfs_write_unlock(inode->i_sb);
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if (barrier_done != 1 && reiserfs_barrier_flush(inode->i_sb))
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blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL,
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BLKDEV_IFL_WAIT);
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if (barrier_done < 0)
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return barrier_done;
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return (err < 0) ? -EIO : 0;
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}
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/* taken fs/buffer.c:__block_commit_write */
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int reiserfs_commit_page(struct inode *inode, struct page *page,
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unsigned from, unsigned to)
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{
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unsigned block_start, block_end;
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int partial = 0;
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unsigned blocksize;
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struct buffer_head *bh, *head;
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unsigned long i_size_index = inode->i_size >> PAGE_CACHE_SHIFT;
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int new;
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int logit = reiserfs_file_data_log(inode);
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struct super_block *s = inode->i_sb;
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int bh_per_page = PAGE_CACHE_SIZE / s->s_blocksize;
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struct reiserfs_transaction_handle th;
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int ret = 0;
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th.t_trans_id = 0;
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blocksize = 1 << inode->i_blkbits;
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if (logit) {
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reiserfs_write_lock(s);
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ret = journal_begin(&th, s, bh_per_page + 1);
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if (ret)
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goto drop_write_lock;
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reiserfs_update_inode_transaction(inode);
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}
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for (bh = head = page_buffers(page), block_start = 0;
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bh != head || !block_start;
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block_start = block_end, bh = bh->b_this_page) {
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new = buffer_new(bh);
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clear_buffer_new(bh);
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block_end = block_start + blocksize;
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if (block_end <= from || block_start >= to) {
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if (!buffer_uptodate(bh))
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partial = 1;
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} else {
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set_buffer_uptodate(bh);
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if (logit) {
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reiserfs_prepare_for_journal(s, bh, 1);
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journal_mark_dirty(&th, s, bh);
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} else if (!buffer_dirty(bh)) {
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mark_buffer_dirty(bh);
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/* do data=ordered on any page past the end
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* of file and any buffer marked BH_New.
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*/
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if (reiserfs_data_ordered(inode->i_sb) &&
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(new || page->index >= i_size_index)) {
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reiserfs_add_ordered_list(inode, bh);
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}
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}
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}
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}
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if (logit) {
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ret = journal_end(&th, s, bh_per_page + 1);
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drop_write_lock:
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reiserfs_write_unlock(s);
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}
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/*
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* If this is a partial write which happened to make all buffers
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* uptodate then we can optimize away a bogus readpage() for
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* the next read(). Here we 'discover' whether the page went
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* uptodate as a result of this (potentially partial) write.
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*/
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if (!partial)
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SetPageUptodate(page);
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return ret;
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}
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/* Write @count bytes at position @ppos in a file indicated by @file
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from the buffer @buf.
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generic_file_write() is only appropriate for filesystems that are not seeking to optimize performance and want
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something simple that works. It is not for serious use by general purpose filesystems, excepting the one that it was
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written for (ext2/3). This is for several reasons:
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* It has no understanding of any filesystem specific optimizations.
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* It enters the filesystem repeatedly for each page that is written.
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* It depends on reiserfs_get_block() function which if implemented by reiserfs performs costly search_by_key
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* operation for each page it is supplied with. By contrast reiserfs_file_write() feeds as much as possible at a time
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* to reiserfs which allows for fewer tree traversals.
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* Each indirect pointer insertion takes a lot of cpu, because it involves memory moves inside of blocks.
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* Asking the block allocation code for blocks one at a time is slightly less efficient.
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All of these reasons for not using only generic file write were understood back when reiserfs was first miscoded to
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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
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things right finally.
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Future Features: providing search_by_key with hints.
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*/
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static ssize_t reiserfs_file_write(struct file *file, /* the file we are going to write into */
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const char __user * buf, /* pointer to user supplied data
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(in userspace) */
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size_t count, /* amount of bytes to write */
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loff_t * ppos /* pointer to position in file that we start writing at. Should be updated to
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* new current position before returning. */
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)
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{
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struct inode *inode = file->f_path.dentry->d_inode; // Inode of the file that we are writing to.
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/* To simplify coding at this time, we store
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locked pages in array for now */
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struct reiserfs_transaction_handle th;
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th.t_trans_id = 0;
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/* If a filesystem is converted from 3.5 to 3.6, we'll have v3.5 items
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* lying around (most of the disk, in fact). Despite the filesystem
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* now being a v3.6 format, the old items still can't support large
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* file sizes. Catch this case here, as the rest of the VFS layer is
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* oblivious to the different limitations between old and new items.
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* reiserfs_setattr catches this for truncates. This chunk is lifted
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* from generic_write_checks. */
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if (get_inode_item_key_version (inode) == KEY_FORMAT_3_5 &&
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*ppos + count > MAX_NON_LFS) {
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if (*ppos >= MAX_NON_LFS) {
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return -EFBIG;
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}
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if (count > MAX_NON_LFS - (unsigned long)*ppos)
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count = MAX_NON_LFS - (unsigned long)*ppos;
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}
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return do_sync_write(file, buf, count, ppos);
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}
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const struct file_operations reiserfs_file_operations = {
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.read = do_sync_read,
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.write = reiserfs_file_write,
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.unlocked_ioctl = reiserfs_ioctl,
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#ifdef CONFIG_COMPAT
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.compat_ioctl = reiserfs_compat_ioctl,
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#endif
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.mmap = generic_file_mmap,
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.open = reiserfs_file_open,
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.release = reiserfs_file_release,
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.fsync = reiserfs_sync_file,
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.aio_read = generic_file_aio_read,
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.aio_write = generic_file_aio_write,
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.splice_read = generic_file_splice_read,
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.splice_write = generic_file_splice_write,
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.llseek = generic_file_llseek,
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};
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const struct inode_operations reiserfs_file_inode_operations = {
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.truncate = reiserfs_vfs_truncate_file,
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.setattr = reiserfs_setattr,
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.setxattr = reiserfs_setxattr,
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.getxattr = reiserfs_getxattr,
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.listxattr = reiserfs_listxattr,
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.removexattr = reiserfs_removexattr,
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.permission = reiserfs_permission,
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};
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