1 files changed, 318 insertions, 0 deletions

diff --git a/fs/reiserfs/tail_conversion.c b/fs/reiserfs/tail_conversion.c
new file mode 100644
index 000000000..b0ae088df
--- /dev/null
+++ b/fs/reiserfs/tail_conversion.c
@@ -0,0 +1,318 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 1999 Hans Reiser, see reiserfs/README for licensing and copyright
+ * details
+ */
+
+#include <linux/time.h>
+#include <linux/pagemap.h>
+#include <linux/buffer_head.h>
+#include "reiserfs.h"
+
+/*
+ * access to tail : when one is going to read tail it must make sure, that is
+ * not running.  direct2indirect and indirect2direct can not run concurrently
+ */
+
+/*
+ * Converts direct items to an unformatted node. Panics if file has no
+ * tail. -ENOSPC if no disk space for conversion
+ */
+/*
+ * path points to first direct item of the file regardless of how many of
+ * them are there
+ */
+int direct2indirect(struct reiserfs_transaction_handle *th, struct inode *inode,
+		    struct treepath *path, struct buffer_head *unbh,
+		    loff_t tail_offset)
+{
+	struct super_block *sb = inode->i_sb;
+	struct buffer_head *up_to_date_bh;
+	struct item_head *p_le_ih = tp_item_head(path);
+	unsigned long total_tail = 0;
+
+	/* Key to search for the last byte of the converted item. */
+	struct cpu_key end_key;
+
+	/*
+	 * new indirect item to be inserted or key
+	 * of unfm pointer to be pasted
+	 */
+	struct item_head ind_ih;
+	int blk_size;
+	/* returned value for reiserfs_insert_item and clones */
+	int  retval;
+	/* Handle on an unformatted node that will be inserted in the tree. */
+	unp_t unfm_ptr;
+
+	BUG_ON(!th->t_trans_id);
+
+	REISERFS_SB(sb)->s_direct2indirect++;
+
+	blk_size = sb->s_blocksize;
+
+	/*
+	 * and key to search for append or insert pointer to the new
+	 * unformatted node.
+	 */
+	copy_item_head(&ind_ih, p_le_ih);
+	set_le_ih_k_offset(&ind_ih, tail_offset);
+	set_le_ih_k_type(&ind_ih, TYPE_INDIRECT);
+
+	/* Set the key to search for the place for new unfm pointer */
+	make_cpu_key(&end_key, inode, tail_offset, TYPE_INDIRECT, 4);
+
+	/* FIXME: we could avoid this */
+	if (search_for_position_by_key(sb, &end_key, path) == POSITION_FOUND) {
+		reiserfs_error(sb, "PAP-14030",
+			       "pasted or inserted byte exists in "
+			       "the tree %K. Use fsck to repair.", &end_key);
+		pathrelse(path);
+		return -EIO;
+	}
+
+	p_le_ih = tp_item_head(path);
+
+	unfm_ptr = cpu_to_le32(unbh->b_blocknr);
+
+	if (is_statdata_le_ih(p_le_ih)) {
+		/* Insert new indirect item. */
+		set_ih_free_space(&ind_ih, 0);	/* delete at nearest future */
+		put_ih_item_len(&ind_ih, UNFM_P_SIZE);
+		PATH_LAST_POSITION(path)++;
+		retval =
+		    reiserfs_insert_item(th, path, &end_key, &ind_ih, inode,
+					 (char *)&unfm_ptr);
+	} else {
+		/* Paste into last indirect item of an object. */
+		retval = reiserfs_paste_into_item(th, path, &end_key, inode,
+						    (char *)&unfm_ptr,
+						    UNFM_P_SIZE);
+	}
+	if (retval) {
+		return retval;
+	}
+	/*
+	 * note: from here there are two keys which have matching first
+	 *  three key components. They only differ by the fourth one.
+	 */
+
+	/* Set the key to search for the direct items of the file */
+	make_cpu_key(&end_key, inode, max_reiserfs_offset(inode), TYPE_DIRECT,
+		     4);
+
+	/*
+	 * Move bytes from the direct items to the new unformatted node
+	 * and delete them.
+	 */
+	while (1) {
+		int tail_size;
+
+		/*
+		 * end_key.k_offset is set so, that we will always have found
+		 * last item of the file
+		 */
+		if (search_for_position_by_key(sb, &end_key, path) ==
+		    POSITION_FOUND)
+			reiserfs_panic(sb, "PAP-14050",
+				       "direct item (%K) not found", &end_key);
+		p_le_ih = tp_item_head(path);
+		RFALSE(!is_direct_le_ih(p_le_ih),
+		       "vs-14055: direct item expected(%K), found %h",
+		       &end_key, p_le_ih);
+		tail_size = (le_ih_k_offset(p_le_ih) & (blk_size - 1))
+		    + ih_item_len(p_le_ih) - 1;
+
+		/*
+		 * we only send the unbh pointer if the buffer is not
+		 * up to date.  this avoids overwriting good data from
+		 * writepage() with old data from the disk or buffer cache
+		 * Special case: unbh->b_page will be NULL if we are coming
+		 * through DIRECT_IO handler here.
+		 */
+		if (!unbh->b_page || buffer_uptodate(unbh)
+		    || PageUptodate(unbh->b_page)) {
+			up_to_date_bh = NULL;
+		} else {
+			up_to_date_bh = unbh;
+		}
+		retval = reiserfs_delete_item(th, path, &end_key, inode,
+						up_to_date_bh);
+
+		total_tail += retval;
+
+		/* done: file does not have direct items anymore */
+		if (tail_size == retval)
+			break;
+
+	}
+	/*
+	 * if we've copied bytes from disk into the page, we need to zero
+	 * out the unused part of the block (it was not up to date before)
+	 */
+	if (up_to_date_bh) {
+		unsigned pgoff =
+		    (tail_offset + total_tail - 1) & (PAGE_SIZE - 1);
+		char *kaddr = kmap_atomic(up_to_date_bh->b_page);
+		memset(kaddr + pgoff, 0, blk_size - total_tail);
+		kunmap_atomic(kaddr);
+	}
+
+	REISERFS_I(inode)->i_first_direct_byte = U32_MAX;
+
+	return 0;
+}
+
+/* stolen from fs/buffer.c */
+void reiserfs_unmap_buffer(struct buffer_head *bh)
+{
+	lock_buffer(bh);
+	if (buffer_journaled(bh) || buffer_journal_dirty(bh)) {
+		BUG();
+	}
+	clear_buffer_dirty(bh);
+	/*
+	 * Remove the buffer from whatever list it belongs to. We are mostly
+	 * interested in removing it from per-sb j_dirty_buffers list, to avoid
+	 * BUG() on attempt to write not mapped buffer
+	 */
+	if ((!list_empty(&bh->b_assoc_buffers) || bh->b_private) && bh->b_page) {
+		struct inode *inode = bh->b_page->mapping->host;
+		struct reiserfs_journal *j = SB_JOURNAL(inode->i_sb);
+		spin_lock(&j->j_dirty_buffers_lock);
+		list_del_init(&bh->b_assoc_buffers);
+		reiserfs_free_jh(bh);
+		spin_unlock(&j->j_dirty_buffers_lock);
+	}
+	clear_buffer_mapped(bh);
+	clear_buffer_req(bh);
+	clear_buffer_new(bh);
+	bh->b_bdev = NULL;
+	unlock_buffer(bh);
+}
+
+/*
+ * this first locks inode (neither reads nor sync are permitted),
+ * reads tail through page cache, insert direct item. When direct item
+ * inserted successfully inode is left locked. Return value is always
+ * what we expect from it (number of cut bytes). But when tail remains
+ * in the unformatted node, we set mode to SKIP_BALANCING and unlock
+ * inode
+ */
+int indirect2direct(struct reiserfs_transaction_handle *th,
+		    struct inode *inode, struct page *page,
+		    struct treepath *path,	/* path to the indirect item. */
+		    const struct cpu_key *item_key,	/* Key to look for
+							 * unformatted node
+							 * pointer to be cut. */
+		    loff_t n_new_file_size,	/* New file size. */
+		    char *mode)
+{
+	struct super_block *sb = inode->i_sb;
+	struct item_head s_ih;
+	unsigned long block_size = sb->s_blocksize;
+	char *tail;
+	int tail_len, round_tail_len;
+	loff_t pos, pos1;	/* position of first byte of the tail */
+	struct cpu_key key;
+
+	BUG_ON(!th->t_trans_id);
+
+	REISERFS_SB(sb)->s_indirect2direct++;
+
+	*mode = M_SKIP_BALANCING;
+
+	/* store item head path points to. */
+	copy_item_head(&s_ih, tp_item_head(path));
+
+	tail_len = (n_new_file_size & (block_size - 1));
+	if (get_inode_sd_version(inode) == STAT_DATA_V2)
+		round_tail_len = ROUND_UP(tail_len);
+	else
+		round_tail_len = tail_len;
+
+	pos =
+	    le_ih_k_offset(&s_ih) - 1 + (ih_item_len(&s_ih) / UNFM_P_SIZE -
+					 1) * sb->s_blocksize;
+	pos1 = pos;
+
+	/*
+	 * we are protected by i_mutex. The tail can not disapper, not
+	 * append can be done either
+	 * we are in truncate or packing tail in file_release
+	 */
+
+	tail = (char *)kmap(page);	/* this can schedule */
+
+	if (path_changed(&s_ih, path)) {
+		/* re-search indirect item */
+		if (search_for_position_by_key(sb, item_key, path)
+		    == POSITION_NOT_FOUND)
+			reiserfs_panic(sb, "PAP-5520",
+				       "item to be converted %K does not exist",
+				       item_key);
+		copy_item_head(&s_ih, tp_item_head(path));
+#ifdef CONFIG_REISERFS_CHECK
+		pos = le_ih_k_offset(&s_ih) - 1 +
+		    (ih_item_len(&s_ih) / UNFM_P_SIZE -
+		     1) * sb->s_blocksize;
+		if (pos != pos1)
+			reiserfs_panic(sb, "vs-5530", "tail position "
+				       "changed while we were reading it");
+#endif
+	}
+
+	/* Set direct item header to insert. */
+	make_le_item_head(&s_ih, NULL, get_inode_item_key_version(inode),
+			  pos1 + 1, TYPE_DIRECT, round_tail_len,
+			  0xffff /*ih_free_space */ );
+
+	/*
+	 * we want a pointer to the first byte of the tail in the page.
+	 * the page was locked and this part of the page was up to date when
+	 * indirect2direct was called, so we know the bytes are still valid
+	 */
+	tail = tail + (pos & (PAGE_SIZE - 1));
+
+	PATH_LAST_POSITION(path)++;
+
+	key = *item_key;
+	set_cpu_key_k_type(&key, TYPE_DIRECT);
+	key.key_length = 4;
+	/* Insert tail as new direct item in the tree */
+	if (reiserfs_insert_item(th, path, &key, &s_ih, inode,
+				 tail ? tail : NULL) < 0) {
+		/*
+		 * No disk memory. So we can not convert last unformatted node
+		 * to the direct item.  In this case we used to adjust
+		 * indirect items's ih_free_space. Now ih_free_space is not
+		 * used, it would be ideal to write zeros to corresponding
+		 * unformatted node. For now i_size is considered as guard for
+		 * going out of file size
+		 */
+		kunmap(page);
+		return block_size - round_tail_len;
+	}
+	kunmap(page);
+
+	/* make sure to get the i_blocks changes from reiserfs_insert_item */
+	reiserfs_update_sd(th, inode);
+
+	/*
+	 * note: we have now the same as in above direct2indirect
+	 * conversion: there are two keys which have matching first three
+	 * key components. They only differ by the fourth one.
+	 */
+
+	/*
+	 * We have inserted new direct item and must remove last
+	 * unformatted node.
+	 */
+	*mode = M_CUT;
+
+	/* we store position of first direct item in the in-core inode */
+	/* mark_file_with_tail (inode, pos1 + 1); */
+	REISERFS_I(inode)->i_first_direct_byte = pos1 + 1;
+
+	return block_size - round_tail_len;
+}