// SPDX-License-Identifier: GPL-2.0+/* * NILFS B-tree node cache * * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. * * 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"  /** * nilfs_init_btnc_inode - initialize B-tree node cache inode * @btnc_inode: inode to be initialized * * nilfs_init_btnc_inode() sets up an inode for B-tree node cache. */void nilfs_init_btnc_inode(struct inode *btnc_inode){	struct nilfs_inode_info *ii = NILFS_I(btnc_inode); 	btnc_inode->i_mode = S_IFREG;	ii->i_flags = 0;	memset(&ii->i_bmap_data, 0, sizeof(struct nilfs_bmap));	mapping_set_gfp_mask(btnc_inode->i_mapping, GFP_NOFS);	btnc_inode->i_mapping->a_ops = &nilfs_buffer_cache_aops;} 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 = btnc->host;	struct buffer_head *bh; 	bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node));	if (unlikely(!bh))		return ERR_PTR(-ENOMEM); 	if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) ||		     buffer_dirty(bh))) {		/*		 * The block buffer at the specified new address was already		 * in use.  This can happen if it is a virtual block number		 * and has been reallocated due to corruption of the bitmap		 * used to manage its allocation state (if not, the buffer		 * clearing of an abandoned b-tree node is missing somewhere).		 */		nilfs_error(inode->i_sb,			    "state inconsistency probably due to duplicate use of b-tree node block address %llu (ino=%lu)",			    (unsigned long long)blocknr, inode->i_ino);		goto failed;	}	memset(bh->b_data, 0, i_blocksize(inode));	bh->b_blocknr = blocknr;	set_buffer_mapped(bh);	set_buffer_uptodate(bh); 	folio_unlock(bh->b_folio);	folio_put(bh->b_folio);	return bh; failed:	folio_unlock(bh->b_folio);	folio_put(bh->b_folio);	brelse(bh);	return ERR_PTR(-EIO);} int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,			      sector_t pblocknr, blk_opf_t opf,			      struct buffer_head **pbh, sector_t *submit_ptr){	struct buffer_head *bh;	struct inode *inode = btnc->host;	struct folio *folio;	int err; 	bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node));	if (unlikely(!bh))		return -ENOMEM; 	err = -EEXIST; /* internal code */	folio = bh->b_folio; 	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 (opf & REQ_RAHEAD) {		if (pblocknr != *submit_ptr + 1 || !trylock_buffer(bh)) {			err = -EBUSY; /* internal code */			brelse(bh);			goto out_locked;		}	} else { /* opf == REQ_OP_READ */		lock_buffer(bh);	}	if (buffer_uptodate(bh)) {		unlock_buffer(bh);		err = -EEXIST; /* internal code */		goto found;	}	set_buffer_mapped(bh);	bh->b_blocknr = pblocknr; /* set block address for read */	bh->b_end_io = end_buffer_read_sync;	get_bh(bh);	submit_bh(opf, bh);	bh->b_blocknr = blocknr; /* set back to the given block address */	*submit_ptr = pblocknr;	err = 0;found:	*pbh = bh; out_locked:	folio_unlock(folio);	folio_put(folio);	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 folio *folio = bh->b_folio;	pgoff_t index = folio->index;	int still_dirty; 	folio_get(folio);	folio_lock(folio);	folio_wait_writeback(folio); 	nilfs_forget_buffer(bh);	still_dirty = folio_test_dirty(folio);	mapping = folio->mapping;	folio_unlock(folio);	folio_put(folio); 	if (!still_dirty && mapping)		invalidate_inode_pages2_range(mapping, index, index);} /** * nilfs_btnode_prepare_change_key - prepare to change the search key of a *                                   b-tree node block * @btnc: page cache in which the b-tree node block is buffered * @ctxt: structure for exchanging context information for key change * * nilfs_btnode_prepare_change_key() prepares to move the contents of the * b-tree node block of the old key given in the "oldkey" member of @ctxt to * the position of the new key given in the "newkey" member of @ctxt in the * page cache @btnc.  Here, the key of the block is an index in units of * blocks, and if the page and block sizes match, it matches the page index * in the page cache. * * If the page size and block size match, this function attempts to move the * entire folio, and in preparation for this, inserts the original folio into * the new index of the cache.  If this insertion fails or if the page size * and block size are different, it falls back to a copy preparation using * nilfs_btnode_create_block(), inserts a new block at the position * corresponding to "newkey", and stores the buffer head pointer in the * "newbh" member of @ctxt. * * Note that the current implementation does not support folio sizes larger * than the page size. * * Return: 0 on success, or the following negative error code on failure. * * %-EIO	- I/O error (metadata corruption). * * %-ENOMEM	- Insufficient memory available. */int nilfs_btnode_prepare_change_key(struct address_space *btnc,				    struct nilfs_btnode_chkey_ctxt *ctxt){	struct buffer_head *obh, *nbh;	struct inode *inode = btnc->host;	__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) {		struct folio *ofolio = obh->b_folio;		folio_lock(ofolio);retry:		/* BUG_ON(oldkey != obh->b_folio->index); */		if (unlikely(oldkey != ofolio->index))			NILFS_FOLIO_BUG(ofolio,				       "invalid oldkey %lld (newkey=%lld)",				       (unsigned long long)oldkey,				       (unsigned long long)newkey); 		xa_lock_irq(&btnc->i_pages);		err = __xa_insert(&btnc->i_pages, newkey, ofolio, GFP_NOFS);		xa_unlock_irq(&btnc->i_pages);		/*		 * Note: folio->index will not change to newkey until		 * nilfs_btnode_commit_change_key() will be called.		 * To protect the folio in intermediate state, the folio lock		 * is held.		 */		if (!err)			return 0;		else if (err != -EBUSY)			goto failed_unlock; 		err = invalidate_inode_pages2_range(btnc, newkey, newkey);		if (!err)			goto retry;		/* fallback to copy mode */		folio_unlock(ofolio);	} 	nbh = nilfs_btnode_create_block(btnc, newkey);	if (IS_ERR(nbh))		return PTR_ERR(nbh); 	BUG_ON(nbh == obh);	ctxt->newbh = nbh;	return 0;  failed_unlock:	folio_unlock(obh->b_folio);	return err;} /** * nilfs_btnode_commit_change_key - commit the change of the search key of *                                  a b-tree node block * @btnc: page cache in which the b-tree node block is buffered * @ctxt: structure for exchanging context information for key change * * nilfs_btnode_commit_change_key() executes the key change based on the * context @ctxt prepared by nilfs_btnode_prepare_change_key().  If no valid * block buffer is prepared in "newbh" of @ctxt (i.e., a full folio move), * this function removes the folio from the old index and completes the move. * Otherwise, it copies the block data and inherited flag states of "oldbh" * to "newbh" and clears the "oldbh" from the cache.  In either case, the * relocated buffer is marked as dirty. * * As with nilfs_btnode_prepare_change_key(), the current implementation does * not support folio sizes larger than the page size. */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 folio *ofolio; 	if (oldkey == newkey)		return; 	if (nbh == NULL) {	/* blocksize == pagesize */		ofolio = obh->b_folio;		if (unlikely(oldkey != ofolio->index))			NILFS_FOLIO_BUG(ofolio,				       "invalid oldkey %lld (newkey=%lld)",				       (unsigned long long)oldkey,				       (unsigned long long)newkey);		mark_buffer_dirty(obh); 		xa_lock_irq(&btnc->i_pages);		__xa_erase(&btnc->i_pages, oldkey);		__xa_set_mark(&btnc->i_pages, newkey, PAGECACHE_TAG_DIRTY);		xa_unlock_irq(&btnc->i_pages); 		ofolio->index = obh->b_blocknr = newkey;		folio_unlock(ofolio);	} 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 of the search key of a *                                 b-tree node block * @btnc: page cache in which the b-tree node block is buffered * @ctxt: structure for exchanging context information for key change * * nilfs_btnode_abort_change_key() cancels the key change associated with the * context @ctxt prepared via nilfs_btnode_prepare_change_key() and performs * any necessary cleanup.  If no valid block buffer is prepared in "newbh" of * @ctxt, this function removes the folio from the destination index and aborts * the move.  Otherwise, it clears "newbh" from the cache. * * As with nilfs_btnode_prepare_change_key(), the current implementation does * not support folio sizes larger than the page size. */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 */		xa_erase_irq(&btnc->i_pages, newkey);		folio_unlock(ctxt->bh->b_folio);	} else {		/*		 * When canceling a buffer that a prepare operation has		 * allocated to copy a node block to another location, use		 * nilfs_btnode_delete() to initialize and release the buffer		 * so that the buffer flags will not be in an inconsistent		 * state when it is reallocated.		 */		nilfs_btnode_delete(nbh);	}}