/* * alloc.c - NILFS dat/inode allocator * * Copyright (C) 2006-2008 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 Koji Sato. * Two allocators were unified by Ryusuke Konishi and Amagai Yoshiji. */ #include <linux/types.h>#include <linux/buffer_head.h>#include <linux/fs.h>#include <linux/bitops.h>#include <linux/slab.h>#include "mdt.h"#include "alloc.h"  /** * nilfs_palloc_groups_per_desc_block - get the number of groups that a group *					descriptor block can maintain * @inode: inode of metadata file using this allocator */static inline unsigned longnilfs_palloc_groups_per_desc_block(const struct inode *inode){	return i_blocksize(inode) /		sizeof(struct nilfs_palloc_group_desc);} /** * nilfs_palloc_groups_count - get maximum number of groups * @inode: inode of metadata file using this allocator */static inline unsigned longnilfs_palloc_groups_count(const struct inode *inode){	return 1UL << (BITS_PER_LONG - (inode->i_blkbits + 3 /* log2(8) */));} /** * nilfs_palloc_init_blockgroup - initialize private variables for allocator * @inode: inode of metadata file using this allocator * @entry_size: size of the persistent object */int nilfs_palloc_init_blockgroup(struct inode *inode, unsigned int entry_size){	struct nilfs_mdt_info *mi = NILFS_MDT(inode); 	mi->mi_bgl = kmalloc(sizeof(*mi->mi_bgl), GFP_NOFS);	if (!mi->mi_bgl)		return -ENOMEM; 	bgl_lock_init(mi->mi_bgl); 	nilfs_mdt_set_entry_size(inode, entry_size, 0); 	mi->mi_blocks_per_group =		DIV_ROUND_UP(nilfs_palloc_entries_per_group(inode),			     mi->mi_entries_per_block) + 1;		/*		 * Number of blocks in a group including entry blocks		 * and a bitmap block		 */	mi->mi_blocks_per_desc_block =		nilfs_palloc_groups_per_desc_block(inode) *		mi->mi_blocks_per_group + 1;		/*		 * Number of blocks per descriptor including the		 * descriptor block		 */	return 0;} /** * nilfs_palloc_group - get group number and offset from an entry number * @inode: inode of metadata file using this allocator * @nr: serial number of the entry (e.g. inode number) * @offset: pointer to store offset number in the group */static unsigned long nilfs_palloc_group(const struct inode *inode, __u64 nr,					unsigned long *offset){	__u64 group = nr; 	*offset = do_div(group, nilfs_palloc_entries_per_group(inode));	return group;} /** * nilfs_palloc_desc_blkoff - get block offset of a group descriptor block * @inode: inode of metadata file using this allocator * @group: group number * * nilfs_palloc_desc_blkoff() returns block offset of the descriptor * block which contains a descriptor of the specified group. */static unsigned longnilfs_palloc_desc_blkoff(const struct inode *inode, unsigned long group){	unsigned long desc_block =		group / nilfs_palloc_groups_per_desc_block(inode);	return desc_block * NILFS_MDT(inode)->mi_blocks_per_desc_block;} /** * nilfs_palloc_bitmap_blkoff - get block offset of a bitmap block * @inode: inode of metadata file using this allocator * @group: group number * * nilfs_palloc_bitmap_blkoff() returns block offset of the bitmap * block used to allocate/deallocate entries in the specified group. */static unsigned longnilfs_palloc_bitmap_blkoff(const struct inode *inode, unsigned long group){	unsigned long desc_offset =		group % nilfs_palloc_groups_per_desc_block(inode);	return nilfs_palloc_desc_blkoff(inode, group) + 1 +		desc_offset * NILFS_MDT(inode)->mi_blocks_per_group;} /** * nilfs_palloc_group_desc_nfrees - get the number of free entries in a group * @desc: pointer to descriptor structure for the group * @lock: spin lock protecting @desc */static unsigned longnilfs_palloc_group_desc_nfrees(const struct nilfs_palloc_group_desc *desc,			       spinlock_t *lock){	unsigned long nfree; 	spin_lock(lock);	nfree = le32_to_cpu(desc->pg_nfrees);	spin_unlock(lock);	return nfree;} /** * nilfs_palloc_group_desc_add_entries - adjust count of free entries * @desc: pointer to descriptor structure for the group * @lock: spin lock protecting @desc * @n: delta to be added */static u32nilfs_palloc_group_desc_add_entries(struct nilfs_palloc_group_desc *desc,				    spinlock_t *lock, u32 n){	u32 nfree; 	spin_lock(lock);	le32_add_cpu(&desc->pg_nfrees, n);	nfree = le32_to_cpu(desc->pg_nfrees);	spin_unlock(lock);	return nfree;} /** * nilfs_palloc_entry_blkoff - get block offset of an entry block * @inode: inode of metadata file using this allocator * @nr: serial number of the entry (e.g. inode number) */static unsigned longnilfs_palloc_entry_blkoff(const struct inode *inode, __u64 nr){	unsigned long group, group_offset; 	group = nilfs_palloc_group(inode, nr, &group_offset); 	return nilfs_palloc_bitmap_blkoff(inode, group) + 1 +		group_offset / NILFS_MDT(inode)->mi_entries_per_block;} /** * nilfs_palloc_desc_block_init - initialize buffer of a group descriptor block * @inode: inode of metadata file * @bh: buffer head of the buffer to be initialized * @kaddr: kernel address mapped for the page including the buffer */static void nilfs_palloc_desc_block_init(struct inode *inode,					 struct buffer_head *bh, void *kaddr){	struct nilfs_palloc_group_desc *desc = kaddr + bh_offset(bh);	unsigned long n = nilfs_palloc_groups_per_desc_block(inode);	__le32 nfrees; 	nfrees = cpu_to_le32(nilfs_palloc_entries_per_group(inode));	while (n-- > 0) {		desc->pg_nfrees = nfrees;		desc++;	}} static int nilfs_palloc_get_block(struct inode *inode, unsigned long blkoff,				  int create,				  void (*init_block)(struct inode *,						     struct buffer_head *,						     void *),				  struct buffer_head **bhp,				  struct nilfs_bh_assoc *prev,				  spinlock_t *lock){	int ret; 	spin_lock(lock);	if (prev->bh && blkoff == prev->blkoff) {		get_bh(prev->bh);		*bhp = prev->bh;		spin_unlock(lock);		return 0;	}	spin_unlock(lock); 	ret = nilfs_mdt_get_block(inode, blkoff, create, init_block, bhp);	if (!ret) {		spin_lock(lock);		/*		 * The following code must be safe for change of the		 * cache contents during the get block call.		 */		brelse(prev->bh);		get_bh(*bhp);		prev->bh = *bhp;		prev->blkoff = blkoff;		spin_unlock(lock);	}	return ret;} /** * nilfs_palloc_delete_block - delete a block on the persistent allocator file * @inode: inode of metadata file using this allocator * @blkoff: block offset * @prev: nilfs_bh_assoc struct of the last used buffer * @lock: spin lock protecting @prev */static int nilfs_palloc_delete_block(struct inode *inode, unsigned long blkoff,				     struct nilfs_bh_assoc *prev,				     spinlock_t *lock){	spin_lock(lock);	if (prev->bh && blkoff == prev->blkoff) {		brelse(prev->bh);		prev->bh = NULL;	}	spin_unlock(lock);	return nilfs_mdt_delete_block(inode, blkoff);} /** * nilfs_palloc_get_desc_block - get buffer head of a group descriptor block * @inode: inode of metadata file using this allocator * @group: group number * @create: create flag * @bhp: pointer to store the resultant buffer head */static int nilfs_palloc_get_desc_block(struct inode *inode,				       unsigned long group,				       int create, struct buffer_head **bhp){	struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache; 	return nilfs_palloc_get_block(inode,				      nilfs_palloc_desc_blkoff(inode, group),				      create, nilfs_palloc_desc_block_init,				      bhp, &cache->prev_desc, &cache->lock);} /** * nilfs_palloc_get_bitmap_block - get buffer head of a bitmap block * @inode: inode of metadata file using this allocator * @group: group number * @create: create flag * @bhp: pointer to store the resultant buffer head */static int nilfs_palloc_get_bitmap_block(struct inode *inode,					 unsigned long group,					 int create, struct buffer_head **bhp){	struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache; 	return nilfs_palloc_get_block(inode,				      nilfs_palloc_bitmap_blkoff(inode, group),				      create, NULL, bhp,				      &cache->prev_bitmap, &cache->lock);} /** * nilfs_palloc_delete_bitmap_block - delete a bitmap block * @inode: inode of metadata file using this allocator * @group: group number */static int nilfs_palloc_delete_bitmap_block(struct inode *inode,					    unsigned long group){	struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache; 	return nilfs_palloc_delete_block(inode,					 nilfs_palloc_bitmap_blkoff(inode,								    group),					 &cache->prev_bitmap, &cache->lock);} /** * nilfs_palloc_get_entry_block - get buffer head of an entry block * @inode: inode of metadata file using this allocator * @nr: serial number of the entry (e.g. inode number) * @create: create flag * @bhp: pointer to store the resultant buffer head */int nilfs_palloc_get_entry_block(struct inode *inode, __u64 nr,				 int create, struct buffer_head **bhp){	struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache; 	return nilfs_palloc_get_block(inode,				      nilfs_palloc_entry_blkoff(inode, nr),				      create, NULL, bhp,				      &cache->prev_entry, &cache->lock);} /** * nilfs_palloc_delete_entry_block - delete an entry block * @inode: inode of metadata file using this allocator * @nr: serial number of the entry */static int nilfs_palloc_delete_entry_block(struct inode *inode, __u64 nr){	struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache; 	return nilfs_palloc_delete_block(inode,					 nilfs_palloc_entry_blkoff(inode, nr),					 &cache->prev_entry, &cache->lock);} /** * nilfs_palloc_block_get_group_desc - get kernel address of a group descriptor * @inode: inode of metadata file using this allocator * @group: group number * @bh: buffer head of the buffer storing the group descriptor block * @kaddr: kernel address mapped for the page including the buffer */static struct nilfs_palloc_group_desc *nilfs_palloc_block_get_group_desc(const struct inode *inode,				  unsigned long group,				  const struct buffer_head *bh, void *kaddr){	return (struct nilfs_palloc_group_desc *)(kaddr + bh_offset(bh)) +		group % nilfs_palloc_groups_per_desc_block(inode);} /** * nilfs_palloc_block_get_entry - get kernel address of an entry * @inode: inode of metadata file using this allocator * @nr: serial number of the entry (e.g. inode number) * @bh: buffer head of the buffer storing the entry block * @kaddr: kernel address mapped for the page including the buffer */void *nilfs_palloc_block_get_entry(const struct inode *inode, __u64 nr,				   const struct buffer_head *bh, void *kaddr){	unsigned long entry_offset, group_offset; 	nilfs_palloc_group(inode, nr, &group_offset);	entry_offset = group_offset % NILFS_MDT(inode)->mi_entries_per_block; 	return kaddr + bh_offset(bh) +		entry_offset * NILFS_MDT(inode)->mi_entry_size;} /** * nilfs_palloc_find_available_slot - find available slot in a group * @bitmap: bitmap of the group * @target: offset number of an entry in the group (start point) * @bsize: size in bits * @lock: spin lock protecting @bitmap */static int nilfs_palloc_find_available_slot(unsigned char *bitmap,					    unsigned long target,					    unsigned int bsize,					    spinlock_t *lock){	int pos, end = bsize; 	if (likely(target < bsize)) {		pos = target;		do {			pos = nilfs_find_next_zero_bit(bitmap, end, pos);			if (pos >= end)				break;			if (!nilfs_set_bit_atomic(lock, pos, bitmap))				return pos;		} while (++pos < end); 		end = target;	} 	/* wrap around */	for (pos = 0; pos < end; pos++) {		pos = nilfs_find_next_zero_bit(bitmap, end, pos);		if (pos >= end)			break;		if (!nilfs_set_bit_atomic(lock, pos, bitmap))			return pos;	} 	return -ENOSPC;} /** * nilfs_palloc_rest_groups_in_desc_block - get the remaining number of groups *					    in a group descriptor block * @inode: inode of metadata file using this allocator * @curr: current group number * @max: maximum number of groups */static unsigned longnilfs_palloc_rest_groups_in_desc_block(const struct inode *inode,				       unsigned long curr, unsigned long max){	return min_t(unsigned long,		     nilfs_palloc_groups_per_desc_block(inode) -		     curr % nilfs_palloc_groups_per_desc_block(inode),		     max - curr + 1);} /** * nilfs_palloc_count_desc_blocks - count descriptor blocks number * @inode: inode of metadata file using this allocator * @desc_blocks: descriptor blocks number [out] */static int nilfs_palloc_count_desc_blocks(struct inode *inode,					    unsigned long *desc_blocks){	__u64 blknum;	int ret; 	ret = nilfs_bmap_last_key(NILFS_I(inode)->i_bmap, &blknum);	if (likely(!ret))		*desc_blocks = DIV_ROUND_UP(			(unsigned long)blknum,			NILFS_MDT(inode)->mi_blocks_per_desc_block);	return ret;} /** * nilfs_palloc_mdt_file_can_grow - check potential opportunity for *					MDT file growing * @inode: inode of metadata file using this allocator * @desc_blocks: known current descriptor blocks count */static inline bool nilfs_palloc_mdt_file_can_grow(struct inode *inode,						    unsigned long desc_blocks){	return (nilfs_palloc_groups_per_desc_block(inode) * desc_blocks) <			nilfs_palloc_groups_count(inode);} /** * nilfs_palloc_count_max_entries - count max number of entries that can be *					described by descriptor blocks count * @inode: inode of metadata file using this allocator * @nused: current number of used entries * @nmaxp: max number of entries [out] */int nilfs_palloc_count_max_entries(struct inode *inode, u64 nused, u64 *nmaxp){	unsigned long desc_blocks = 0;	u64 entries_per_desc_block, nmax;	int err; 	err = nilfs_palloc_count_desc_blocks(inode, &desc_blocks);	if (unlikely(err))		return err; 	entries_per_desc_block = (u64)nilfs_palloc_entries_per_group(inode) *				nilfs_palloc_groups_per_desc_block(inode);	nmax = entries_per_desc_block * desc_blocks; 	if (nused == nmax &&			nilfs_palloc_mdt_file_can_grow(inode, desc_blocks))		nmax += entries_per_desc_block; 	if (nused > nmax)		return -ERANGE; 	*nmaxp = nmax;	return 0;}

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