1 // SPDX-License-Identifier: GPL-2.0
6  *  AV, Sep--Dec 2000
14 enum {DIRECT = 10, DEPTH = 4};	/* Have triple indirect */  enumerator
23 static int block_to_path(struct inode *inode, long block, int offsets[DEPTH])  in block_to_path()  argument
25 	struct super_block *sb = inode->i_sb;  in block_to_path()
27 	int ptrs_bits = sbi->s_ind_per_block_bits;  in block_to_path()
28 	unsigned long	indirect_blocks = sbi->s_ind_per_block,  in block_to_path()
29 			double_blocks = sbi->s_ind_per_block_2;  in block_to_path()
36 	} else if ( (block -= DIRECT) < indirect_blocks) {  in block_to_path()
39 	} else if ((block -= indirect_blocks) < double_blocks) {  in block_to_path()
42 		offsets[n++] = block & (indirect_blocks - 1);  in block_to_path()
43 	} else if (((block -= double_blocks) >> (ptrs_bits * 2)) < indirect_blocks) {  in block_to_path()
46 		offsets[n++] = (block >> ptrs_bits) & (indirect_blocks - 1);  in block_to_path()
47 		offsets[n++] = block & (indirect_blocks - 1);  in block_to_path()
56 	return sbi->s_block_base + fs32_to_cpu(sbi, nr);  in block_to_cpu()
69 	p->key = *(p->p = v);  in add_chain()
70 	p->bh = bh;  in add_chain()
75 	while (from <= to && from->key == *from->p)  in verify_chain()
82 	return (sysv_zone_t*)((char*)bh->b_data + bh->b_size);  in block_end()
89 			    int depth,  in get_branch()  argument
94 	struct super_block *sb = inode->i_sb;  in get_branch()
99 	add_chain(chain, NULL, SYSV_I(inode)->i_data + *offsets);  in get_branch()
100 	if (!p->key)  in get_branch()
102 	while (--depth) {  in get_branch()
103 		int block = block_to_cpu(SYSV_SB(sb), p->key);  in get_branch()
109 		add_chain(++p, bh, (sysv_zone_t*)bh->b_data + *++offsets);  in get_branch()
110 		if (!p->key)  in get_branch()
117 	*err = -EAGAIN;  in get_branch()
120 	*err = -EIO;  in get_branch()
130 	int blocksize = inode->i_sb->s_blocksize;  in alloc_branch()
134 	branch[0].key = sysv_new_block(inode->i_sb);  in alloc_branch()
139 		branch[n].key = sysv_new_block(inode->i_sb);  in alloc_branch()
146 		parent = block_to_cpu(SYSV_SB(inode->i_sb), branch[n-1].key);  in alloc_branch()
147 		bh = sb_getblk(inode->i_sb, parent);  in alloc_branch()
149 		memset(bh->b_data, 0, blocksize);  in alloc_branch()
151 		branch[n].p = (sysv_zone_t*) bh->b_data + offsets[n];  in alloc_branch()
164 		sysv_free_block(inode->i_sb, branch[i].key);  in alloc_branch()
165 	return -ENOSPC;  in alloc_branch()
177 	if (!verify_chain(chain, where-1) || *where->p)  in splice_branch()
179 	*where->p = where->key;  in splice_branch()
182 	inode->i_ctime = current_time(inode);  in splice_branch()
185 	if (where->bh)  in splice_branch()
186 		dirty_indirect(where->bh, inode);  in splice_branch()
199 		sysv_free_block(inode->i_sb, where[i].key);  in splice_branch()
200 	return -EAGAIN;  in splice_branch()
205 	int err = -EIO;  in get_block()
206 	int offsets[DEPTH];  in get_block()
207 	Indirect chain[DEPTH];  in get_block()
208 	struct super_block *sb = inode->i_sb;  in get_block()
211 	int depth = block_to_path(inode, iblock, offsets);  in get_block()  local
213 	if (depth == 0)  in get_block()
218 	partial = get_branch(inode, depth, offsets, chain, &err);  in get_block()
221 	/* Simplest case - block found, no allocation needed */  in get_block()
225 					chain[depth-1].key));  in get_block()
227 		partial = chain+depth-1; /* the whole chain */  in get_block()
231 	/* Next simple case - plain lookup or failed read of indirect block */  in get_block()
232 	if (!create || err == -EIO) {  in get_block()
235 			brelse(partial->bh);  in get_block()
236 			partial--;  in get_block()
247 	if (err == -EAGAIN)  in get_block()
250 	left = (chain + depth) - partial;  in get_block()
251 	err = alloc_branch(inode, left, offsets+(partial-chain), partial);  in get_block()
263 		brelse(partial->bh);  in get_block()
264 		partial--;  in get_block()
278 				int depth,  in find_shared()  argument
287 	for (k = depth; k > 1 && !offsets[k-1]; k--)  in find_shared()
293 		partial = chain + k-1;  in find_shared()
295 	 * If the branch acquired continuation since we've looked at it -  in find_shared()
298 	if (!partial->key && *partial->p) {  in find_shared()
302 	for (p=partial; p>chain && all_zeroes((sysv_zone_t*)p->bh->b_data,p->p); p--)  in find_shared()
308 	 * it's easier to cheat and just decrement partial->p.  in find_shared()
310 	if (p == chain + k - 1 && p > chain) {  in find_shared()
311 		p->p--;  in find_shared()
313 		*top = *p->p;  in find_shared()
314 		*p->p = 0;  in find_shared()
319 		brelse(partial->bh);  in find_shared()
320 		partial--;  in find_shared()
332 			sysv_free_block(inode->i_sb, nr);  in free_data()
338 static void free_branches(struct inode *inode, sysv_zone_t *p, sysv_zone_t *q, int depth)  in free_branches()  argument
341 	struct super_block *sb = inode->i_sb;  in free_branches()
343 	if (depth--) {  in free_branches()
354 			free_branches(inode, (sysv_zone_t*)bh->b_data,  in free_branches()
355 					block_end(bh), depth);  in free_branches()
366 	sysv_zone_t *i_data = SYSV_I(inode)->i_data;  in sysv_truncate()
367 	int offsets[DEPTH];  in sysv_truncate()
368 	Indirect chain[DEPTH];  in sysv_truncate()
375 	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||  in sysv_truncate()
376 	    S_ISLNK(inode->i_mode)))  in sysv_truncate()
379 	blocksize = inode->i_sb->s_blocksize;  in sysv_truncate()
380 	iblock = (inode->i_size + blocksize-1)  in sysv_truncate()
381 					>> inode->i_sb->s_blocksize_bits;  in sysv_truncate()
383 	block_truncate_page(inode->i_mapping, inode->i_size, get_block);  in sysv_truncate()
400 			dirty_indirect(partial->bh, inode);  in sysv_truncate()
401 		free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);  in sysv_truncate()
405 		free_branches(inode, partial->p + 1, block_end(partial->bh),  in sysv_truncate()
406 				(chain+n-1) - partial);  in sysv_truncate()
407 		dirty_indirect(partial->bh, inode);  in sysv_truncate()
408 		brelse (partial->bh);  in sysv_truncate()
409 		partial--;  in sysv_truncate()
413 	while (n < DEPTH) {  in sysv_truncate()
414 		nr = i_data[DIRECT + n - 1];  in sysv_truncate()
416 			i_data[DIRECT + n - 1] = 0;  in sysv_truncate()
422 	inode->i_mtime = inode->i_ctime = current_time(inode);  in sysv_truncate()
432 	int ptrs_bits = sbi->s_ind_per_block_bits;  in sysv_nblocks()
433 	unsigned blocks, res, direct = DIRECT, i = DEPTH;  in sysv_nblocks()
434 	blocks = (size + s->s_blocksize - 1) >> s->s_blocksize_bits;  in sysv_nblocks()
436 	while (--i && blocks > direct) {  in sysv_nblocks()
437 		blocks = ((blocks - direct - 1) >> ptrs_bits) + 1;  in sysv_nblocks()
447 	struct super_block *s = path->dentry->d_sb;  in sysv_getattr()
448 	generic_fillattr(d_inode(path->dentry), stat);  in sysv_getattr()
449 	stat->blocks = (s->s_blocksize / 512) * sysv_nblocks(s, stat->size);  in sysv_getattr()
450 	stat->blksize = s->s_blocksize;  in sysv_getattr()
471 	struct inode *inode = mapping->host;  in sysv_write_failed()
473 	if (to > inode->i_size) {  in sysv_write_failed()
474 		truncate_pagecache(inode, inode->i_size);  in sysv_write_failed()