/* * btnode.c - NILFS B-tree node cache * * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * GNU General Public License for more details. * * Originally written by Seiji Kihara. * Fully revised by Ryusuke Konishi for stabilization and simplification. * */ #include <linux/types.h>#include <linux/buffer_head.h>#include <linux/mm.h>#include <linux/backing-dev.h>#include <linux/gfp.h>#include "nilfs.h"#include "mdt.h"#include "dat.h"#include "page.h"#include "btnode.h" void nilfs_btnode_cache_clear(struct address_space *btnc){	invalidate_mapping_pages(btnc, 0, -1);	truncate_inode_pages(btnc, 0);} struct buffer_head *nilfs_btnode_create_block(struct address_space *btnc, __u64 blocknr){	struct inode *inode = NILFS_BTNC_I(btnc);	struct buffer_head *bh; 	bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node));	if (unlikely(!bh))		return NULL; 	if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) ||		     buffer_dirty(bh))) {		brelse(bh);		BUG();	}	memset(bh->b_data, 0, i_blocksize(inode));	bh->b_bdev = inode->i_sb->s_bdev;	bh->b_blocknr = blocknr;	set_buffer_mapped(bh);	set_buffer_uptodate(bh); 	unlock_page(bh->b_page);	put_page(bh->b_page);	return bh;} int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,			      sector_t pblocknr, int mode, int mode_flags,			      struct buffer_head **pbh, sector_t *submit_ptr){	struct buffer_head *bh;	struct inode *inode = NILFS_BTNC_I(btnc);	struct page *page;	int err; 	bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node));	if (unlikely(!bh))		return -ENOMEM; 	err = -EEXIST; /* internal code */	page = bh->b_page; 	if (buffer_uptodate(bh) || buffer_dirty(bh))		goto found; 	if (pblocknr == 0) {		pblocknr = blocknr;		if (inode->i_ino != NILFS_DAT_INO) {			struct the_nilfs *nilfs = inode->i_sb->s_fs_info; 			/* blocknr is a virtual block number */			err = nilfs_dat_translate(nilfs->ns_dat, blocknr,						  &pblocknr);			if (unlikely(err)) {				brelse(bh);				goto out_locked;			}		}	} 	if (mode_flags & REQ_RAHEAD) {		if (pblocknr != *submit_ptr + 1 || !trylock_buffer(bh)) {			err = -EBUSY; /* internal code */			brelse(bh);			goto out_locked;		}	} else { /* mode == READ */		lock_buffer(bh);	}	if (buffer_uptodate(bh)) {		unlock_buffer(bh);		err = -EEXIST; /* internal code */		goto found;	}	set_buffer_mapped(bh);	bh->b_bdev = inode->i_sb->s_bdev;	bh->b_blocknr = pblocknr; /* set block address for read */	bh->b_end_io = end_buffer_read_sync;	get_bh(bh);	submit_bh(mode, mode_flags, bh);	bh->b_blocknr = blocknr; /* set back to the given block address */	*submit_ptr = pblocknr;	err = 0;found:	*pbh = bh; out_locked:	unlock_page(page);	put_page(page);	return err;} /** * nilfs_btnode_delete - delete B-tree node buffer * @bh: buffer to be deleted * * nilfs_btnode_delete() invalidates the specified buffer and delete the page * including the buffer if the page gets unbusy. */void nilfs_btnode_delete(struct buffer_head *bh){	struct address_space *mapping;	struct page *page = bh->b_page;	pgoff_t index = page_index(page);	int still_dirty; 	get_page(page);	lock_page(page);	wait_on_page_writeback(page); 	nilfs_forget_buffer(bh);	still_dirty = PageDirty(page);	mapping = page->mapping;	unlock_page(page);	put_page(page); 	if (!still_dirty && mapping)		invalidate_inode_pages2_range(mapping, index, index);} /** * nilfs_btnode_prepare_change_key *  prepare to move contents of the block for old key to one of new key. *  the old buffer will not be removed, but might be reused for new buffer. *  it might return -ENOMEM because of memory allocation errors, *  and might return -EIO because of disk read errors. */int nilfs_btnode_prepare_change_key(struct address_space *btnc,				    struct nilfs_btnode_chkey_ctxt *ctxt){	struct buffer_head *obh, *nbh;	struct inode *inode = NILFS_BTNC_I(btnc);	__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;	int err; 	if (oldkey == newkey)		return 0; 	obh = ctxt->bh;	ctxt->newbh = NULL; 	if (inode->i_blkbits == PAGE_SHIFT) {		lock_page(obh->b_page);		/*		 * We cannot call radix_tree_preload for the kernels older		 * than 2.6.23, because it is not exported for modules.		 */retry:		err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);		if (err)			goto failed_unlock;		/* BUG_ON(oldkey != obh->b_page->index); */		if (unlikely(oldkey != obh->b_page->index))			NILFS_PAGE_BUG(obh->b_page,				       "invalid oldkey %lld (newkey=%lld)",				       (unsigned long long)oldkey,				       (unsigned long long)newkey); 		spin_lock_irq(&btnc->tree_lock);		err = radix_tree_insert(&btnc->page_tree, newkey, obh->b_page);		spin_unlock_irq(&btnc->tree_lock);		/*		 * Note: page->index will not change to newkey until		 * nilfs_btnode_commit_change_key() will be called.		 * To protect the page in intermediate state, the page lock		 * is held.		 */		radix_tree_preload_end();		if (!err)			return 0;		else if (err != -EEXIST)			goto failed_unlock; 		err = invalidate_inode_pages2_range(btnc, newkey, newkey);		if (!err)			goto retry;		/* fallback to copy mode */		unlock_page(obh->b_page);	} 	nbh = nilfs_btnode_create_block(btnc, newkey);	if (!nbh)		return -ENOMEM; 	BUG_ON(nbh == obh);	ctxt->newbh = nbh;	return 0;  failed_unlock:	unlock_page(obh->b_page);	return err;} /** * nilfs_btnode_commit_change_key *  commit the change_key operation prepared by prepare_change_key(). */void nilfs_btnode_commit_change_key(struct address_space *btnc,				    struct nilfs_btnode_chkey_ctxt *ctxt){	struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh;	__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;	struct page *opage; 	if (oldkey == newkey)		return; 	if (nbh == NULL) {	/* blocksize == pagesize */		opage = obh->b_page;		if (unlikely(oldkey != opage->index))			NILFS_PAGE_BUG(opage,				       "invalid oldkey %lld (newkey=%lld)",				       (unsigned long long)oldkey,				       (unsigned long long)newkey);		mark_buffer_dirty(obh); 		spin_lock_irq(&btnc->tree_lock);		radix_tree_delete(&btnc->page_tree, oldkey);		radix_tree_tag_set(&btnc->page_tree, newkey,				   PAGECACHE_TAG_DIRTY);		spin_unlock_irq(&btnc->tree_lock); 		opage->index = obh->b_blocknr = newkey;		unlock_page(opage);	} else {		nilfs_copy_buffer(nbh, obh);		mark_buffer_dirty(nbh); 		nbh->b_blocknr = newkey;		ctxt->bh = nbh;		nilfs_btnode_delete(obh); /* will decrement bh->b_count */	}} /** * nilfs_btnode_abort_change_key *  abort the change_key operation prepared by prepare_change_key(). */void nilfs_btnode_abort_change_key(struct address_space *btnc,				   struct nilfs_btnode_chkey_ctxt *ctxt){	struct buffer_head *nbh = ctxt->newbh;	__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey; 	if (oldkey == newkey)		return; 	if (nbh == NULL) {	/* blocksize == pagesize */		spin_lock_irq(&btnc->tree_lock);		radix_tree_delete(&btnc->page_tree, newkey);		spin_unlock_irq(&btnc->tree_lock);		unlock_page(ctxt->bh->b_page);	} else		brelse(nbh);}