280 lines
9.3 KiB
C
280 lines
9.3 KiB
C
/*
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* Copyright 1999 Hans Reiser, see reiserfs/README for licensing and copyright details
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*/
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#include <linux/config.h>
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#include <linux/time.h>
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#include <linux/pagemap.h>
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#include <linux/buffer_head.h>
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#include <linux/reiserfs_fs.h>
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/* access to tail : when one is going to read tail it must make sure, that is not running.
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direct2indirect and indirect2direct can not run concurrently */
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/* Converts direct items to an unformatted node. Panics if file has no
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tail. -ENOSPC if no disk space for conversion */
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/* path points to first direct item of the file regarless of how many of
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them are there */
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int direct2indirect(struct reiserfs_transaction_handle *th, struct inode *inode,
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struct path *path, struct buffer_head *unbh,
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loff_t tail_offset)
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{
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struct super_block *sb = inode->i_sb;
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struct buffer_head *up_to_date_bh;
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struct item_head *p_le_ih = PATH_PITEM_HEAD(path);
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unsigned long total_tail = 0;
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struct cpu_key end_key; /* Key to search for the last byte of the
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converted item. */
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struct item_head ind_ih; /* new indirect item to be inserted or
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key of unfm pointer to be pasted */
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int n_blk_size, n_retval; /* returned value for reiserfs_insert_item and clones */
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unp_t unfm_ptr; /* Handle on an unformatted node
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that will be inserted in the
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tree. */
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BUG_ON(!th->t_trans_id);
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REISERFS_SB(sb)->s_direct2indirect++;
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n_blk_size = sb->s_blocksize;
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/* and key to search for append or insert pointer to the new
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unformatted node. */
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copy_item_head(&ind_ih, p_le_ih);
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set_le_ih_k_offset(&ind_ih, tail_offset);
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set_le_ih_k_type(&ind_ih, TYPE_INDIRECT);
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/* Set the key to search for the place for new unfm pointer */
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make_cpu_key(&end_key, inode, tail_offset, TYPE_INDIRECT, 4);
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// FIXME: we could avoid this
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if (search_for_position_by_key(sb, &end_key, path) == POSITION_FOUND) {
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reiserfs_warning(sb, "PAP-14030: direct2indirect: "
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"pasted or inserted byte exists in the tree %K. "
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"Use fsck to repair.", &end_key);
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pathrelse(path);
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return -EIO;
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}
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p_le_ih = PATH_PITEM_HEAD(path);
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unfm_ptr = cpu_to_le32(unbh->b_blocknr);
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if (is_statdata_le_ih(p_le_ih)) {
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/* Insert new indirect item. */
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set_ih_free_space(&ind_ih, 0); /* delete at nearest future */
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put_ih_item_len(&ind_ih, UNFM_P_SIZE);
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PATH_LAST_POSITION(path)++;
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n_retval =
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reiserfs_insert_item(th, path, &end_key, &ind_ih, inode,
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(char *)&unfm_ptr);
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} else {
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/* Paste into last indirect item of an object. */
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n_retval = reiserfs_paste_into_item(th, path, &end_key, inode,
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(char *)&unfm_ptr,
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UNFM_P_SIZE);
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}
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if (n_retval) {
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return n_retval;
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}
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// note: from here there are two keys which have matching first
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// three key components. They only differ by the fourth one.
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/* Set the key to search for the direct items of the file */
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make_cpu_key(&end_key, inode, max_reiserfs_offset(inode), TYPE_DIRECT,
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4);
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/* Move bytes from the direct items to the new unformatted node
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and delete them. */
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while (1) {
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int tail_size;
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/* end_key.k_offset is set so, that we will always have found
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last item of the file */
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if (search_for_position_by_key(sb, &end_key, path) ==
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POSITION_FOUND)
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reiserfs_panic(sb,
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"PAP-14050: direct2indirect: "
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"direct item (%K) not found", &end_key);
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p_le_ih = PATH_PITEM_HEAD(path);
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RFALSE(!is_direct_le_ih(p_le_ih),
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"vs-14055: direct item expected(%K), found %h",
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&end_key, p_le_ih);
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tail_size = (le_ih_k_offset(p_le_ih) & (n_blk_size - 1))
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+ ih_item_len(p_le_ih) - 1;
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/* we only send the unbh pointer if the buffer is not up to date.
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** this avoids overwriting good data from writepage() with old data
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** from the disk or buffer cache
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** Special case: unbh->b_page will be NULL if we are coming through
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** DIRECT_IO handler here.
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*/
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if (!unbh->b_page || buffer_uptodate(unbh)
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|| PageUptodate(unbh->b_page)) {
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up_to_date_bh = NULL;
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} else {
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up_to_date_bh = unbh;
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}
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n_retval = reiserfs_delete_item(th, path, &end_key, inode,
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up_to_date_bh);
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total_tail += n_retval;
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if (tail_size == n_retval)
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// done: file does not have direct items anymore
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break;
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}
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/* if we've copied bytes from disk into the page, we need to zero
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** out the unused part of the block (it was not up to date before)
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*/
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if (up_to_date_bh) {
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unsigned pgoff =
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(tail_offset + total_tail - 1) & (PAGE_CACHE_SIZE - 1);
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char *kaddr = kmap_atomic(up_to_date_bh->b_page, KM_USER0);
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memset(kaddr + pgoff, 0, n_blk_size - total_tail);
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kunmap_atomic(kaddr, KM_USER0);
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}
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REISERFS_I(inode)->i_first_direct_byte = U32_MAX;
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return 0;
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}
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/* stolen from fs/buffer.c */
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void reiserfs_unmap_buffer(struct buffer_head *bh)
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{
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lock_buffer(bh);
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if (buffer_journaled(bh) || buffer_journal_dirty(bh)) {
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BUG();
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}
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clear_buffer_dirty(bh);
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/* Remove the buffer from whatever list it belongs to. We are mostly
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interested in removing it from per-sb j_dirty_buffers list, to avoid
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BUG() on attempt to write not mapped buffer */
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if ((!list_empty(&bh->b_assoc_buffers) || bh->b_private) && bh->b_page) {
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struct inode *inode = bh->b_page->mapping->host;
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struct reiserfs_journal *j = SB_JOURNAL(inode->i_sb);
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spin_lock(&j->j_dirty_buffers_lock);
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list_del_init(&bh->b_assoc_buffers);
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reiserfs_free_jh(bh);
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spin_unlock(&j->j_dirty_buffers_lock);
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}
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clear_buffer_mapped(bh);
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clear_buffer_req(bh);
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clear_buffer_new(bh);
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bh->b_bdev = NULL;
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unlock_buffer(bh);
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}
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/* this first locks inode (neither reads nor sync are permitted),
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reads tail through page cache, insert direct item. When direct item
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inserted successfully inode is left locked. Return value is always
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what we expect from it (number of cut bytes). But when tail remains
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in the unformatted node, we set mode to SKIP_BALANCING and unlock
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inode */
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int indirect2direct(struct reiserfs_transaction_handle *th, struct inode *p_s_inode, struct page *page, struct path *p_s_path, /* path to the indirect item. */
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const struct cpu_key *p_s_item_key, /* Key to look for unformatted node pointer to be cut. */
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loff_t n_new_file_size, /* New file size. */
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char *p_c_mode)
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{
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struct super_block *p_s_sb = p_s_inode->i_sb;
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struct item_head s_ih;
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unsigned long n_block_size = p_s_sb->s_blocksize;
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char *tail;
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int tail_len, round_tail_len;
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loff_t pos, pos1; /* position of first byte of the tail */
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struct cpu_key key;
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BUG_ON(!th->t_trans_id);
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REISERFS_SB(p_s_sb)->s_indirect2direct++;
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*p_c_mode = M_SKIP_BALANCING;
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/* store item head path points to. */
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copy_item_head(&s_ih, PATH_PITEM_HEAD(p_s_path));
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tail_len = (n_new_file_size & (n_block_size - 1));
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if (get_inode_sd_version(p_s_inode) == STAT_DATA_V2)
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round_tail_len = ROUND_UP(tail_len);
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else
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round_tail_len = tail_len;
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pos =
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le_ih_k_offset(&s_ih) - 1 + (ih_item_len(&s_ih) / UNFM_P_SIZE -
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1) * p_s_sb->s_blocksize;
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pos1 = pos;
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// we are protected by i_mutex. The tail can not disapper, not
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// append can be done either
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// we are in truncate or packing tail in file_release
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tail = (char *)kmap(page); /* this can schedule */
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if (path_changed(&s_ih, p_s_path)) {
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/* re-search indirect item */
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if (search_for_position_by_key(p_s_sb, p_s_item_key, p_s_path)
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== POSITION_NOT_FOUND)
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reiserfs_panic(p_s_sb,
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"PAP-5520: indirect2direct: "
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"item to be converted %K does not exist",
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p_s_item_key);
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copy_item_head(&s_ih, PATH_PITEM_HEAD(p_s_path));
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#ifdef CONFIG_REISERFS_CHECK
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pos = le_ih_k_offset(&s_ih) - 1 +
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(ih_item_len(&s_ih) / UNFM_P_SIZE -
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1) * p_s_sb->s_blocksize;
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if (pos != pos1)
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reiserfs_panic(p_s_sb, "vs-5530: indirect2direct: "
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"tail position changed while we were reading it");
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#endif
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}
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/* Set direct item header to insert. */
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make_le_item_head(&s_ih, NULL, get_inode_item_key_version(p_s_inode),
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pos1 + 1, TYPE_DIRECT, round_tail_len,
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0xffff /*ih_free_space */ );
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/* we want a pointer to the first byte of the tail in the page.
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** the page was locked and this part of the page was up to date when
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** indirect2direct was called, so we know the bytes are still valid
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*/
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tail = tail + (pos & (PAGE_CACHE_SIZE - 1));
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PATH_LAST_POSITION(p_s_path)++;
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key = *p_s_item_key;
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set_cpu_key_k_type(&key, TYPE_DIRECT);
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key.key_length = 4;
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/* Insert tail as new direct item in the tree */
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if (reiserfs_insert_item(th, p_s_path, &key, &s_ih, p_s_inode,
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tail ? tail : NULL) < 0) {
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/* No disk memory. So we can not convert last unformatted node
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to the direct item. In this case we used to adjust
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indirect items's ih_free_space. Now ih_free_space is not
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used, it would be ideal to write zeros to corresponding
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unformatted node. For now i_size is considered as guard for
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going out of file size */
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kunmap(page);
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return n_block_size - round_tail_len;
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}
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kunmap(page);
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/* make sure to get the i_blocks changes from reiserfs_insert_item */
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reiserfs_update_sd(th, p_s_inode);
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// note: we have now the same as in above direct2indirect
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// conversion: there are two keys which have matching first three
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// key components. They only differ by the fouhth one.
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/* We have inserted new direct item and must remove last
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unformatted node. */
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*p_c_mode = M_CUT;
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/* we store position of first direct item in the in-core inode */
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//mark_file_with_tail (p_s_inode, pos1 + 1);
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REISERFS_I(p_s_inode)->i_first_direct_byte = pos1 + 1;
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return n_block_size - round_tail_len;
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}
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