diff options
Diffstat (limited to 'fs/reiserfs/tail_conversion.c')
| -rw-r--r-- | fs/reiserfs/tail_conversion.c | 276 |
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 000000000000..6191909d5165 --- /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; +} + + + |