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-rw-r--r--fs/reiserfs/tail_conversion.c276
1 files changed, 276 insertions, 0 deletions
diff --git a/fs/reiserfs/tail_conversion.c b/fs/reiserfs/tail_conversion.c
new file mode 100644
index 0000000..6191909
--- /dev/null
+++ b/fs/reiserfs/tail_conversion.c
@@ -0,0 +1,276 @@
+/*
+ * Copyright 1999 Hans Reiser, see reiserfs/README for licensing and copyright details
+ */
+
+#include <linux/config.h>
+#include <linux/time.h>
+#include <linux/pagemap.h>
+#include <linux/buffer_head.h>
+#include <linux/reiserfs_fs.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 regarless of how many of
+ them are there */
+int direct2indirect (struct reiserfs_transaction_handle *th, struct inode * inode,
+ struct path * 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 = PATH_PITEM_HEAD (path);
+ unsigned long total_tail = 0 ;
+ struct cpu_key end_key; /* Key to search for the last byte of the
+ converted item. */
+ struct item_head ind_ih; /* new indirect item to be inserted or
+ key of unfm pointer to be pasted */
+ int n_blk_size,
+ n_retval; /* returned value for reiserfs_insert_item and clones */
+ unp_t unfm_ptr; /* Handle on an unformatted node
+ that will be inserted in the
+ tree. */
+
+ BUG_ON (!th->t_trans_id);
+
+ REISERFS_SB(sb)->s_direct2indirect ++;
+
+ n_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_warning (sb, "PAP-14030: direct2indirect: "
+ "pasted or inserted byte exists in the tree %K. "
+ "Use fsck to repair.", &end_key);
+ pathrelse(path);
+ return -EIO;
+ }
+
+ p_le_ih = PATH_PITEM_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)++;
+ n_retval = reiserfs_insert_item (th, path, &end_key, &ind_ih, inode,
+ (char *)&unfm_ptr);
+ } else {
+ /* Paste into last indirect item of an object. */
+ n_retval = reiserfs_paste_into_item(th, path, &end_key, inode,
+ (char *)&unfm_ptr, UNFM_P_SIZE);
+ }
+ if ( n_retval ) {
+ return n_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: direct2indirect: "
+ "direct item (%K) not found", &end_key);
+ p_le_ih = PATH_PITEM_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) & (n_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 ;
+ }
+ n_retval = reiserfs_delete_item (th, path, &end_key, inode,
+ up_to_date_bh) ;
+
+ total_tail += n_retval ;
+ if (tail_size == n_retval)
+ // done: file does not have direct items anymore
+ 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_CACHE_SIZE - 1);
+ char *kaddr=kmap_atomic(up_to_date_bh->b_page, KM_USER0);
+ memset(kaddr + pgoff, 0, n_blk_size - total_tail) ;
+ kunmap_atomic(kaddr, KM_USER0);
+ }
+
+ 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 * p_s_inode,
+ struct page *page,
+ struct path * p_s_path, /* path to the indirect item. */
+ const struct cpu_key * p_s_item_key, /* Key to look for unformatted node pointer to be cut. */
+ loff_t n_new_file_size, /* New file size. */
+ char * p_c_mode)
+{
+ struct super_block * p_s_sb = p_s_inode->i_sb;
+ struct item_head s_ih;
+ unsigned long n_block_size = p_s_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(p_s_sb)->s_indirect2direct ++;
+
+ *p_c_mode = M_SKIP_BALANCING;
+
+ /* store item head path points to. */
+ copy_item_head (&s_ih, PATH_PITEM_HEAD(p_s_path));
+
+ tail_len = (n_new_file_size & (n_block_size - 1));
+ if (get_inode_sd_version (p_s_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) * p_s_sb->s_blocksize;
+ pos1 = pos;
+
+ // we are protected by i_sem. 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, p_s_path)) {
+ /* re-search indirect item */
+ if ( search_for_position_by_key (p_s_sb, p_s_item_key, p_s_path) == POSITION_NOT_FOUND )
+ reiserfs_panic(p_s_sb, "PAP-5520: indirect2direct: "
+ "item to be converted %K does not exist", p_s_item_key);
+ copy_item_head(&s_ih, PATH_PITEM_HEAD(p_s_path));
+#ifdef CONFIG_REISERFS_CHECK
+ pos = le_ih_k_offset (&s_ih) - 1 +
+ (ih_item_len(&s_ih) / UNFM_P_SIZE - 1) * p_s_sb->s_blocksize;
+ if (pos != pos1)
+ reiserfs_panic (p_s_sb, "vs-5530: indirect2direct: "
+ "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 (p_s_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_CACHE_SIZE - 1)) ;
+
+ PATH_LAST_POSITION(p_s_path)++;
+
+ key = *p_s_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, p_s_path, &key, &s_ih, p_s_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 n_block_size - round_tail_len;
+ }
+ kunmap(page) ;
+
+ /* make sure to get the i_blocks changes from reiserfs_insert_item */
+ reiserfs_update_sd(th, p_s_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 fouhth one.
+
+ /* We have inserted new direct item and must remove last
+ unformatted node. */
+ *p_c_mode = M_CUT;
+
+ /* we store position of first direct item in the in-core inode */
+ //mark_file_with_tail (p_s_inode, pos1 + 1);
+ REISERFS_I(p_s_inode)->i_first_direct_byte = pos1 + 1;
+
+ return n_block_size - round_tail_len;
+}
+
+
+
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