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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *  linux/fs/affs/file.c
   4 *
   5 *  (c) 1996  Hans-Joachim Widmaier - Rewritten
   6 *
   7 *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
   8 *
   9 *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
  10 *
  11 *  (C) 1991  Linus Torvalds - minix filesystem
  12 *
  13 *  affs regular file handling primitives
  14 */
  15
  16#include <linux/uio.h>
  17#include <linux/blkdev.h>
  18#include <linux/mpage.h>
  19#include "affs.h"
  20
  21static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
  22
  23static int
  24affs_file_open(struct inode *inode, struct file *filp)
  25{
  26	pr_debug("open(%lu,%d)\n",
  27		 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  28	atomic_inc(&AFFS_I(inode)->i_opencnt);
  29	return 0;
  30}
  31
  32static int
  33affs_file_release(struct inode *inode, struct file *filp)
  34{
  35	pr_debug("release(%lu, %d)\n",
  36		 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  37
  38	if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
  39		inode_lock(inode);
  40		if (inode->i_size != AFFS_I(inode)->mmu_private)
  41			affs_truncate(inode);
  42		affs_free_prealloc(inode);
  43		inode_unlock(inode);
  44	}
  45
  46	return 0;
  47}
  48
  49static int
  50affs_grow_extcache(struct inode *inode, u32 lc_idx)
  51{
  52	struct super_block	*sb = inode->i_sb;
  53	struct buffer_head	*bh;
  54	u32 lc_max;
  55	int i, j, key;
  56
  57	if (!AFFS_I(inode)->i_lc) {
  58		char *ptr = (char *)get_zeroed_page(GFP_NOFS);
  59		if (!ptr)
  60			return -ENOMEM;
  61		AFFS_I(inode)->i_lc = (u32 *)ptr;
  62		AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
  63	}
  64
  65	lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
  66
  67	if (AFFS_I(inode)->i_extcnt > lc_max) {
  68		u32 lc_shift, lc_mask, tmp, off;
  69
  70		/* need to recalculate linear cache, start from old size */
  71		lc_shift = AFFS_I(inode)->i_lc_shift;
  72		tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
  73		for (; tmp; tmp >>= 1)
  74			lc_shift++;
  75		lc_mask = (1 << lc_shift) - 1;
  76
  77		/* fix idx and old size to new shift */
  78		lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  79		AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  80
  81		/* first shrink old cache to make more space */
  82		off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
  83		for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
  84			AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
  85
  86		AFFS_I(inode)->i_lc_shift = lc_shift;
  87		AFFS_I(inode)->i_lc_mask = lc_mask;
  88	}
  89
  90	/* fill cache to the needed index */
  91	i = AFFS_I(inode)->i_lc_size;
  92	AFFS_I(inode)->i_lc_size = lc_idx + 1;
  93	for (; i <= lc_idx; i++) {
  94		if (!i) {
  95			AFFS_I(inode)->i_lc[0] = inode->i_ino;
  96			continue;
  97		}
  98		key = AFFS_I(inode)->i_lc[i - 1];
  99		j = AFFS_I(inode)->i_lc_mask + 1;
 100		// unlock cache
 101		for (; j > 0; j--) {
 102			bh = affs_bread(sb, key);
 103			if (!bh)
 104				goto err;
 105			key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 106			affs_brelse(bh);
 107		}
 108		// lock cache
 109		AFFS_I(inode)->i_lc[i] = key;
 110	}
 111
 112	return 0;
 113
 114err:
 115	// lock cache
 116	return -EIO;
 117}
 118
 119static struct buffer_head *
 120affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
 121{
 122	struct super_block *sb = inode->i_sb;
 123	struct buffer_head *new_bh;
 124	u32 blocknr, tmp;
 125
 126	blocknr = affs_alloc_block(inode, bh->b_blocknr);
 127	if (!blocknr)
 128		return ERR_PTR(-ENOSPC);
 129
 130	new_bh = affs_getzeroblk(sb, blocknr);
 131	if (!new_bh) {
 132		affs_free_block(sb, blocknr);
 133		return ERR_PTR(-EIO);
 134	}
 135
 136	AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
 137	AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
 138	AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
 139	AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
 140	affs_fix_checksum(sb, new_bh);
 141
 142	mark_buffer_dirty_inode(new_bh, inode);
 143
 144	tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 145	if (tmp)
 146		affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
 147	AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
 148	affs_adjust_checksum(bh, blocknr - tmp);
 149	mark_buffer_dirty_inode(bh, inode);
 150
 151	AFFS_I(inode)->i_extcnt++;
 152	mark_inode_dirty(inode);
 153
 154	return new_bh;
 155}
 156
 157static inline struct buffer_head *
 158affs_get_extblock(struct inode *inode, u32 ext)
 159{
 160	/* inline the simplest case: same extended block as last time */
 161	struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
 162	if (ext == AFFS_I(inode)->i_ext_last)
 163		get_bh(bh);
 164	else
 165		/* we have to do more (not inlined) */
 166		bh = affs_get_extblock_slow(inode, ext);
 167
 168	return bh;
 169}
 170
 171static struct buffer_head *
 172affs_get_extblock_slow(struct inode *inode, u32 ext)
 173{
 174	struct super_block *sb = inode->i_sb;
 175	struct buffer_head *bh;
 176	u32 ext_key;
 177	u32 lc_idx, lc_off, ac_idx;
 178	u32 tmp, idx;
 179
 180	if (ext == AFFS_I(inode)->i_ext_last + 1) {
 181		/* read the next extended block from the current one */
 182		bh = AFFS_I(inode)->i_ext_bh;
 183		ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 184		if (ext < AFFS_I(inode)->i_extcnt)
 185			goto read_ext;
 186		BUG_ON(ext > AFFS_I(inode)->i_extcnt);
 187		bh = affs_alloc_extblock(inode, bh, ext);
 188		if (IS_ERR(bh))
 189			return bh;
 190		goto store_ext;
 191	}
 192
 193	if (ext == 0) {
 194		/* we seek back to the file header block */
 195		ext_key = inode->i_ino;
 196		goto read_ext;
 197	}
 198
 199	if (ext >= AFFS_I(inode)->i_extcnt) {
 200		struct buffer_head *prev_bh;
 201
 202		/* allocate a new extended block */
 203		BUG_ON(ext > AFFS_I(inode)->i_extcnt);
 204
 205		/* get previous extended block */
 206		prev_bh = affs_get_extblock(inode, ext - 1);
 207		if (IS_ERR(prev_bh))
 208			return prev_bh;
 209		bh = affs_alloc_extblock(inode, prev_bh, ext);
 210		affs_brelse(prev_bh);
 211		if (IS_ERR(bh))
 212			return bh;
 213		goto store_ext;
 214	}
 215
 216again:
 217	/* check if there is an extended cache and whether it's large enough */
 218	lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
 219	lc_off = ext & AFFS_I(inode)->i_lc_mask;
 220
 221	if (lc_idx >= AFFS_I(inode)->i_lc_size) {
 222		int err;
 223
 224		err = affs_grow_extcache(inode, lc_idx);
 225		if (err)
 226			return ERR_PTR(err);
 227		goto again;
 228	}
 229
 230	/* every n'th key we find in the linear cache */
 231	if (!lc_off) {
 232		ext_key = AFFS_I(inode)->i_lc[lc_idx];
 233		goto read_ext;
 234	}
 235
 236	/* maybe it's still in the associative cache */
 237	ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
 238	if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
 239		ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
 240		goto read_ext;
 241	}
 242
 243	/* try to find one of the previous extended blocks */
 244	tmp = ext;
 245	idx = ac_idx;
 246	while (--tmp, --lc_off > 0) {
 247		idx = (idx - 1) & AFFS_AC_MASK;
 248		if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
 249			ext_key = AFFS_I(inode)->i_ac[idx].key;
 250			goto find_ext;
 251		}
 252	}
 253
 254	/* fall back to the linear cache */
 255	ext_key = AFFS_I(inode)->i_lc[lc_idx];
 256find_ext:
 257	/* read all extended blocks until we find the one we need */
 258	//unlock cache
 259	do {
 260		bh = affs_bread(sb, ext_key);
 261		if (!bh)
 262			goto err_bread;
 263		ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 264		affs_brelse(bh);
 265		tmp++;
 266	} while (tmp < ext);
 267	//lock cache
 268
 269	/* store it in the associative cache */
 270	// recalculate ac_idx?
 271	AFFS_I(inode)->i_ac[ac_idx].ext = ext;
 272	AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
 273
 274read_ext:
 275	/* finally read the right extended block */
 276	//unlock cache
 277	bh = affs_bread(sb, ext_key);
 278	if (!bh)
 279		goto err_bread;
 280	//lock cache
 281
 282store_ext:
 283	/* release old cached extended block and store the new one */
 284	affs_brelse(AFFS_I(inode)->i_ext_bh);
 285	AFFS_I(inode)->i_ext_last = ext;
 286	AFFS_I(inode)->i_ext_bh = bh;
 287	get_bh(bh);
 288
 289	return bh;
 290
 291err_bread:
 292	affs_brelse(bh);
 293	return ERR_PTR(-EIO);
 294}
 295
 296static int
 297affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
 298{
 299	struct super_block	*sb = inode->i_sb;
 300	struct buffer_head	*ext_bh;
 301	u32			 ext;
 302
 303	pr_debug("%s(%lu, %llu)\n", __func__, inode->i_ino,
 304		 (unsigned long long)block);
 305
 306	BUG_ON(block > (sector_t)0x7fffffffUL);
 307
 308	if (block >= AFFS_I(inode)->i_blkcnt) {
 309		if (block > AFFS_I(inode)->i_blkcnt || !create)
 310			goto err_big;
 311	} else
 312		create = 0;
 313
 314	//lock cache
 315	affs_lock_ext(inode);
 316
 317	ext = (u32)block / AFFS_SB(sb)->s_hashsize;
 318	block -= ext * AFFS_SB(sb)->s_hashsize;
 319	ext_bh = affs_get_extblock(inode, ext);
 320	if (IS_ERR(ext_bh))
 321		goto err_ext;
 322	map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
 323
 324	if (create) {
 325		u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
 326		if (!blocknr)
 327			goto err_alloc;
 328		set_buffer_new(bh_result);
 329		AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
 330		AFFS_I(inode)->i_blkcnt++;
 331
 332		/* store new block */
 333		if (bh_result->b_blocknr)
 334			affs_warning(sb, "get_block",
 335				     "block already set (%llx)",
 336				     (unsigned long long)bh_result->b_blocknr);
 337		AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
 338		AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
 339		affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
 340		bh_result->b_blocknr = blocknr;
 341
 342		if (!block) {
 343			/* insert first block into header block */
 344			u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
 345			if (tmp)
 346				affs_warning(sb, "get_block", "first block already set (%d)", tmp);
 347			AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
 348			affs_adjust_checksum(ext_bh, blocknr - tmp);
 349		}
 350	}
 351
 352	affs_brelse(ext_bh);
 353	//unlock cache
 354	affs_unlock_ext(inode);
 355	return 0;
 356
 357err_big:
 358	affs_error(inode->i_sb, "get_block", "strange block request %llu",
 359		   (unsigned long long)block);
 360	return -EIO;
 361err_ext:
 362	// unlock cache
 363	affs_unlock_ext(inode);
 364	return PTR_ERR(ext_bh);
 365err_alloc:
 366	brelse(ext_bh);
 367	clear_buffer_mapped(bh_result);
 368	bh_result->b_bdev = NULL;
 369	// unlock cache
 370	affs_unlock_ext(inode);
 371	return -ENOSPC;
 372}
 373
 374static int affs_writepages(struct address_space *mapping,
 375			   struct writeback_control *wbc)
 376{
 377	return mpage_writepages(mapping, wbc, affs_get_block);
 378}
 379
 380static int affs_read_folio(struct file *file, struct folio *folio)
 381{
 382	return block_read_full_folio(folio, affs_get_block);
 383}
 384
 385static void affs_write_failed(struct address_space *mapping, loff_t to)
 386{
 387	struct inode *inode = mapping->host;
 388
 389	if (to > inode->i_size) {
 390		truncate_pagecache(inode, inode->i_size);
 391		affs_truncate(inode);
 392	}
 393}
 394
 395static ssize_t
 396affs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 397{
 398	struct file *file = iocb->ki_filp;
 399	struct address_space *mapping = file->f_mapping;
 400	struct inode *inode = mapping->host;
 401	size_t count = iov_iter_count(iter);
 402	loff_t offset = iocb->ki_pos;
 403	ssize_t ret;
 404
 405	if (iov_iter_rw(iter) == WRITE) {
 406		loff_t size = offset + count;
 407
 408		if (AFFS_I(inode)->mmu_private < size)
 409			return 0;
 410	}
 411
 412	ret = blockdev_direct_IO(iocb, inode, iter, affs_get_block);
 413	if (ret < 0 && iov_iter_rw(iter) == WRITE)
 414		affs_write_failed(mapping, offset + count);
 415	return ret;
 416}
 417
 418static int affs_write_begin(struct file *file, struct address_space *mapping,
 419			loff_t pos, unsigned len,
 420			struct page **pagep, void **fsdata)
 421{
 422	int ret;
 423
 424	*pagep = NULL;
 425	ret = cont_write_begin(file, mapping, pos, len, pagep, fsdata,
 426				affs_get_block,
 427				&AFFS_I(mapping->host)->mmu_private);
 428	if (unlikely(ret))
 429		affs_write_failed(mapping, pos + len);
 430
 431	return ret;
 432}
 433
 434static int affs_write_end(struct file *file, struct address_space *mapping,
 435			  loff_t pos, unsigned int len, unsigned int copied,
 436			  struct page *page, void *fsdata)
 437{
 438	struct inode *inode = mapping->host;
 439	int ret;
 440
 441	ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
 442
 443	/* Clear Archived bit on file writes, as AmigaOS would do */
 444	if (AFFS_I(inode)->i_protect & FIBF_ARCHIVED) {
 445		AFFS_I(inode)->i_protect &= ~FIBF_ARCHIVED;
 446		mark_inode_dirty(inode);
 447	}
 448
 449	return ret;
 450}
 451
 452static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 453{
 454	return generic_block_bmap(mapping,block,affs_get_block);
 455}
 456
 457const struct address_space_operations affs_aops = {
 458	.dirty_folio	= block_dirty_folio,
 459	.invalidate_folio = block_invalidate_folio,
 460	.read_folio = affs_read_folio,
 461	.writepages = affs_writepages,
 462	.write_begin = affs_write_begin,
 463	.write_end = affs_write_end,
 464	.direct_IO = affs_direct_IO,
 465	.migrate_folio = buffer_migrate_folio,
 466	.bmap = _affs_bmap
 467};
 468
 469static inline struct buffer_head *
 470affs_bread_ino(struct inode *inode, int block, int create)
 471{
 472	struct buffer_head *bh, tmp_bh;
 473	int err;
 474
 475	tmp_bh.b_state = 0;
 476	err = affs_get_block(inode, block, &tmp_bh, create);
 477	if (!err) {
 478		bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
 479		if (bh) {
 480			bh->b_state |= tmp_bh.b_state;
 481			return bh;
 482		}
 483		err = -EIO;
 484	}
 485	return ERR_PTR(err);
 486}
 487
 488static inline struct buffer_head *
 489affs_getzeroblk_ino(struct inode *inode, int block)
 490{
 491	struct buffer_head *bh, tmp_bh;
 492	int err;
 493
 494	tmp_bh.b_state = 0;
 495	err = affs_get_block(inode, block, &tmp_bh, 1);
 496	if (!err) {
 497		bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
 498		if (bh) {
 499			bh->b_state |= tmp_bh.b_state;
 500			return bh;
 501		}
 502		err = -EIO;
 503	}
 504	return ERR_PTR(err);
 505}
 506
 507static inline struct buffer_head *
 508affs_getemptyblk_ino(struct inode *inode, int block)
 509{
 510	struct buffer_head *bh, tmp_bh;
 511	int err;
 512
 513	tmp_bh.b_state = 0;
 514	err = affs_get_block(inode, block, &tmp_bh, 1);
 515	if (!err) {
 516		bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
 517		if (bh) {
 518			bh->b_state |= tmp_bh.b_state;
 519			return bh;
 520		}
 521		err = -EIO;
 522	}
 523	return ERR_PTR(err);
 524}
 525
 526static int affs_do_read_folio_ofs(struct folio *folio, size_t to, int create)
 
 527{
 528	struct inode *inode = folio->mapping->host;
 529	struct super_block *sb = inode->i_sb;
 530	struct buffer_head *bh;
 531	size_t pos = 0;
 532	size_t bidx, boff, bsize;
 
 533	u32 tmp;
 534
 535	pr_debug("%s(%lu, %ld, 0, %zu)\n", __func__, inode->i_ino,
 536		 folio->index, to);
 537	BUG_ON(to > folio_size(folio));
 538	bsize = AFFS_SB(sb)->s_data_blksize;
 539	tmp = folio_pos(folio);
 540	bidx = tmp / bsize;
 541	boff = tmp % bsize;
 542
 543	while (pos < to) {
 544		bh = affs_bread_ino(inode, bidx, create);
 545		if (IS_ERR(bh))
 546			return PTR_ERR(bh);
 547		tmp = min(bsize - boff, to - pos);
 548		BUG_ON(pos + tmp > to || tmp > bsize);
 549		memcpy_to_folio(folio, pos, AFFS_DATA(bh) + boff, tmp);
 
 
 550		affs_brelse(bh);
 551		bidx++;
 552		pos += tmp;
 553		boff = 0;
 554	}
 
 555	return 0;
 556}
 557
 558static int
 559affs_extent_file_ofs(struct inode *inode, u32 newsize)
 560{
 561	struct super_block *sb = inode->i_sb;
 562	struct buffer_head *bh, *prev_bh;
 563	u32 bidx, boff;
 564	u32 size, bsize;
 565	u32 tmp;
 566
 567	pr_debug("%s(%lu, %d)\n", __func__, inode->i_ino, newsize);
 568	bsize = AFFS_SB(sb)->s_data_blksize;
 569	bh = NULL;
 570	size = AFFS_I(inode)->mmu_private;
 571	bidx = size / bsize;
 572	boff = size % bsize;
 573	if (boff) {
 574		bh = affs_bread_ino(inode, bidx, 0);
 575		if (IS_ERR(bh))
 576			return PTR_ERR(bh);
 577		tmp = min(bsize - boff, newsize - size);
 578		BUG_ON(boff + tmp > bsize || tmp > bsize);
 579		memset(AFFS_DATA(bh) + boff, 0, tmp);
 580		be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 581		affs_fix_checksum(sb, bh);
 582		mark_buffer_dirty_inode(bh, inode);
 583		size += tmp;
 584		bidx++;
 585	} else if (bidx) {
 586		bh = affs_bread_ino(inode, bidx - 1, 0);
 587		if (IS_ERR(bh))
 588			return PTR_ERR(bh);
 589	}
 590
 591	while (size < newsize) {
 592		prev_bh = bh;
 593		bh = affs_getzeroblk_ino(inode, bidx);
 594		if (IS_ERR(bh))
 595			goto out;
 596		tmp = min(bsize, newsize - size);
 597		BUG_ON(tmp > bsize);
 598		AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 599		AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 600		AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 601		AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 602		affs_fix_checksum(sb, bh);
 603		bh->b_state &= ~(1UL << BH_New);
 604		mark_buffer_dirty_inode(bh, inode);
 605		if (prev_bh) {
 606			u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 607
 608			if (tmp_next)
 609				affs_warning(sb, "extent_file_ofs",
 610					     "next block already set for %d (%d)",
 611					     bidx, tmp_next);
 612			AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 613			affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 614			mark_buffer_dirty_inode(prev_bh, inode);
 615			affs_brelse(prev_bh);
 616		}
 617		size += bsize;
 618		bidx++;
 619	}
 620	affs_brelse(bh);
 621	inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 622	return 0;
 623
 624out:
 625	inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 626	return PTR_ERR(bh);
 627}
 628
 629static int affs_read_folio_ofs(struct file *file, struct folio *folio)
 
 630{
 631	struct inode *inode = folio->mapping->host;
 632	size_t to;
 633	int err;
 634
 635	pr_debug("%s(%lu, %ld)\n", __func__, inode->i_ino, folio->index);
 636	to = folio_size(folio);
 637	if (folio_pos(folio) + to > inode->i_size) {
 638		to = inode->i_size - folio_pos(folio);
 639		folio_zero_segment(folio, to, folio_size(folio));
 640	}
 641
 642	err = affs_do_read_folio_ofs(folio, to, 0);
 643	if (!err)
 644		folio_mark_uptodate(folio);
 645	folio_unlock(folio);
 646	return err;
 647}
 648
 649static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 650				loff_t pos, unsigned len,
 651				struct page **pagep, void **fsdata)
 652{
 653	struct inode *inode = mapping->host;
 654	struct folio *folio;
 655	pgoff_t index;
 656	int err = 0;
 657
 658	pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 659		 pos + len);
 660	if (pos > AFFS_I(inode)->mmu_private) {
 661		/* XXX: this probably leaves a too-big i_size in case of
 662		 * failure. Should really be updating i_size at write_end time
 663		 */
 664		err = affs_extent_file_ofs(inode, pos);
 665		if (err)
 666			return err;
 667	}
 668
 669	index = pos >> PAGE_SHIFT;
 670	folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
 671			mapping_gfp_mask(mapping));
 672	if (IS_ERR(folio))
 673		return PTR_ERR(folio);
 674	*pagep = &folio->page;
 675
 676	if (folio_test_uptodate(folio))
 677		return 0;
 678
 679	/* XXX: inefficient but safe in the face of short writes */
 680	err = affs_do_read_folio_ofs(folio, folio_size(folio), 1);
 681	if (err) {
 682		folio_unlock(folio);
 683		folio_put(folio);
 684	}
 685	return err;
 686}
 687
 688static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 689				loff_t pos, unsigned len, unsigned copied,
 690				struct page *page, void *fsdata)
 691{
 692	struct folio *folio = page_folio(page);
 693	struct inode *inode = mapping->host;
 694	struct super_block *sb = inode->i_sb;
 695	struct buffer_head *bh, *prev_bh;
 696	char *data;
 697	u32 bidx, boff, bsize;
 698	unsigned from, to;
 699	u32 tmp;
 700	int written;
 701
 702	from = pos & (PAGE_SIZE - 1);
 703	to = from + len;
 704	/*
 705	 * XXX: not sure if this can handle short copies (len < copied), but
 706	 * we don't have to, because the folio should always be uptodate here,
 707	 * due to write_begin.
 708	 */
 709
 710	pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 711		 pos + len);
 712	bsize = AFFS_SB(sb)->s_data_blksize;
 713	data = folio_address(folio);
 714
 715	bh = NULL;
 716	written = 0;
 717	tmp = (folio->index << PAGE_SHIFT) + from;
 718	bidx = tmp / bsize;
 719	boff = tmp % bsize;
 720	if (boff) {
 721		bh = affs_bread_ino(inode, bidx, 0);
 722		if (IS_ERR(bh)) {
 723			written = PTR_ERR(bh);
 724			goto err_first_bh;
 725		}
 726		tmp = min(bsize - boff, to - from);
 727		BUG_ON(boff + tmp > bsize || tmp > bsize);
 728		memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 729		be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 730		affs_fix_checksum(sb, bh);
 731		mark_buffer_dirty_inode(bh, inode);
 732		written += tmp;
 733		from += tmp;
 734		bidx++;
 735	} else if (bidx) {
 736		bh = affs_bread_ino(inode, bidx - 1, 0);
 737		if (IS_ERR(bh)) {
 738			written = PTR_ERR(bh);
 739			goto err_first_bh;
 740		}
 741	}
 742	while (from + bsize <= to) {
 743		prev_bh = bh;
 744		bh = affs_getemptyblk_ino(inode, bidx);
 745		if (IS_ERR(bh))
 746			goto err_bh;
 747		memcpy(AFFS_DATA(bh), data + from, bsize);
 748		if (buffer_new(bh)) {
 749			AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 750			AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 751			AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 752			AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 753			AFFS_DATA_HEAD(bh)->next = 0;
 754			bh->b_state &= ~(1UL << BH_New);
 755			if (prev_bh) {
 756				u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 757
 758				if (tmp_next)
 759					affs_warning(sb, "commit_write_ofs",
 760						     "next block already set for %d (%d)",
 761						     bidx, tmp_next);
 762				AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 763				affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 764				mark_buffer_dirty_inode(prev_bh, inode);
 765			}
 766		}
 767		affs_brelse(prev_bh);
 768		affs_fix_checksum(sb, bh);
 769		mark_buffer_dirty_inode(bh, inode);
 770		written += bsize;
 771		from += bsize;
 772		bidx++;
 773	}
 774	if (from < to) {
 775		prev_bh = bh;
 776		bh = affs_bread_ino(inode, bidx, 1);
 777		if (IS_ERR(bh))
 778			goto err_bh;
 779		tmp = min(bsize, to - from);
 780		BUG_ON(tmp > bsize);
 781		memcpy(AFFS_DATA(bh), data + from, tmp);
 782		if (buffer_new(bh)) {
 783			AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 784			AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 785			AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 786			AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 787			AFFS_DATA_HEAD(bh)->next = 0;
 788			bh->b_state &= ~(1UL << BH_New);
 789			if (prev_bh) {
 790				u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 791
 792				if (tmp_next)
 793					affs_warning(sb, "commit_write_ofs",
 794						     "next block already set for %d (%d)",
 795						     bidx, tmp_next);
 796				AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 797				affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 798				mark_buffer_dirty_inode(prev_bh, inode);
 799			}
 800		} else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 801			AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 802		affs_brelse(prev_bh);
 803		affs_fix_checksum(sb, bh);
 804		mark_buffer_dirty_inode(bh, inode);
 805		written += tmp;
 806		from += tmp;
 807		bidx++;
 808	}
 809	folio_mark_uptodate(folio);
 810
 811done:
 812	affs_brelse(bh);
 813	tmp = (folio->index << PAGE_SHIFT) + from;
 814	if (tmp > inode->i_size)
 815		inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 816
 817	/* Clear Archived bit on file writes, as AmigaOS would do */
 818	if (AFFS_I(inode)->i_protect & FIBF_ARCHIVED) {
 819		AFFS_I(inode)->i_protect &= ~FIBF_ARCHIVED;
 820		mark_inode_dirty(inode);
 821	}
 822
 823err_first_bh:
 824	folio_unlock(folio);
 825	folio_put(folio);
 826
 827	return written;
 828
 829err_bh:
 830	bh = prev_bh;
 831	if (!written)
 832		written = PTR_ERR(bh);
 833	goto done;
 834}
 835
 836const struct address_space_operations affs_aops_ofs = {
 837	.dirty_folio	= block_dirty_folio,
 838	.invalidate_folio = block_invalidate_folio,
 839	.read_folio = affs_read_folio_ofs,
 840	//.writepages = affs_writepages_ofs,
 841	.write_begin = affs_write_begin_ofs,
 842	.write_end = affs_write_end_ofs,
 843	.migrate_folio = filemap_migrate_folio,
 844};
 845
 846/* Free any preallocated blocks. */
 847
 848void
 849affs_free_prealloc(struct inode *inode)
 850{
 851	struct super_block *sb = inode->i_sb;
 852
 853	pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
 854
 855	while (AFFS_I(inode)->i_pa_cnt) {
 856		AFFS_I(inode)->i_pa_cnt--;
 857		affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 858	}
 859}
 860
 861/* Truncate (or enlarge) a file to the requested size. */
 862
 863void
 864affs_truncate(struct inode *inode)
 865{
 866	struct super_block *sb = inode->i_sb;
 867	u32 ext, ext_key;
 868	u32 last_blk, blkcnt, blk;
 869	u32 size;
 870	struct buffer_head *ext_bh;
 871	int i;
 872
 873	pr_debug("truncate(inode=%lu, oldsize=%llu, newsize=%llu)\n",
 874		 inode->i_ino, AFFS_I(inode)->mmu_private, inode->i_size);
 875
 876	last_blk = 0;
 877	ext = 0;
 878	if (inode->i_size) {
 879		last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 880		ext = last_blk / AFFS_SB(sb)->s_hashsize;
 881	}
 882
 883	if (inode->i_size > AFFS_I(inode)->mmu_private) {
 884		struct address_space *mapping = inode->i_mapping;
 885		struct page *page;
 886		void *fsdata = NULL;
 887		loff_t isize = inode->i_size;
 888		int res;
 889
 890		res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, &page, &fsdata);
 891		if (!res)
 892			res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
 893		else
 894			inode->i_size = AFFS_I(inode)->mmu_private;
 895		mark_inode_dirty(inode);
 896		return;
 897	} else if (inode->i_size == AFFS_I(inode)->mmu_private)
 898		return;
 899
 900	// lock cache
 901	ext_bh = affs_get_extblock(inode, ext);
 902	if (IS_ERR(ext_bh)) {
 903		affs_warning(sb, "truncate",
 904			     "unexpected read error for ext block %u (%ld)",
 905			     ext, PTR_ERR(ext_bh));
 906		return;
 907	}
 908	if (AFFS_I(inode)->i_lc) {
 909		/* clear linear cache */
 910		i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 911		if (AFFS_I(inode)->i_lc_size > i) {
 912			AFFS_I(inode)->i_lc_size = i;
 913			for (; i < AFFS_LC_SIZE; i++)
 914				AFFS_I(inode)->i_lc[i] = 0;
 915		}
 916		/* clear associative cache */
 917		for (i = 0; i < AFFS_AC_SIZE; i++)
 918			if (AFFS_I(inode)->i_ac[i].ext >= ext)
 919				AFFS_I(inode)->i_ac[i].ext = 0;
 920	}
 921	ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 922
 923	blkcnt = AFFS_I(inode)->i_blkcnt;
 924	i = 0;
 925	blk = last_blk;
 926	if (inode->i_size) {
 927		i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 928		blk++;
 929	} else
 930		AFFS_HEAD(ext_bh)->first_data = 0;
 931	AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 932	size = AFFS_SB(sb)->s_hashsize;
 933	if (size > blkcnt - blk + i)
 934		size = blkcnt - blk + i;
 935	for (; i < size; i++, blk++) {
 936		affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 937		AFFS_BLOCK(sb, ext_bh, i) = 0;
 938	}
 939	AFFS_TAIL(sb, ext_bh)->extension = 0;
 940	affs_fix_checksum(sb, ext_bh);
 941	mark_buffer_dirty_inode(ext_bh, inode);
 942	affs_brelse(ext_bh);
 943
 944	if (inode->i_size) {
 945		AFFS_I(inode)->i_blkcnt = last_blk + 1;
 946		AFFS_I(inode)->i_extcnt = ext + 1;
 947		if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS)) {
 948			struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 949			u32 tmp;
 950			if (IS_ERR(bh)) {
 951				affs_warning(sb, "truncate",
 952					     "unexpected read error for last block %u (%ld)",
 953					     ext, PTR_ERR(bh));
 954				return;
 955			}
 956			tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 957			AFFS_DATA_HEAD(bh)->next = 0;
 958			affs_adjust_checksum(bh, -tmp);
 959			affs_brelse(bh);
 960		}
 961	} else {
 962		AFFS_I(inode)->i_blkcnt = 0;
 963		AFFS_I(inode)->i_extcnt = 1;
 964	}
 965	AFFS_I(inode)->mmu_private = inode->i_size;
 966	// unlock cache
 967
 968	while (ext_key) {
 969		ext_bh = affs_bread(sb, ext_key);
 970		size = AFFS_SB(sb)->s_hashsize;
 971		if (size > blkcnt - blk)
 972			size = blkcnt - blk;
 973		for (i = 0; i < size; i++, blk++)
 974			affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 975		affs_free_block(sb, ext_key);
 976		ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 977		affs_brelse(ext_bh);
 978	}
 979	affs_free_prealloc(inode);
 980}
 981
 982int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 983{
 984	struct inode *inode = filp->f_mapping->host;
 985	int ret, err;
 986
 987	err = file_write_and_wait_range(filp, start, end);
 988	if (err)
 989		return err;
 990
 991	inode_lock(inode);
 992	ret = write_inode_now(inode, 0);
 993	err = sync_blockdev(inode->i_sb->s_bdev);
 994	if (!ret)
 995		ret = err;
 996	inode_unlock(inode);
 997	return ret;
 998}
 999const struct file_operations affs_file_operations = {
1000	.llseek		= generic_file_llseek,
1001	.read_iter	= generic_file_read_iter,
1002	.write_iter	= generic_file_write_iter,
1003	.mmap		= generic_file_mmap,
1004	.open		= affs_file_open,
1005	.release	= affs_file_release,
1006	.fsync		= affs_file_fsync,
1007	.splice_read	= filemap_splice_read,
1008};
1009
1010const struct inode_operations affs_file_inode_operations = {
1011	.setattr	= affs_notify_change,
1012};
   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *  linux/fs/affs/file.c
   4 *
   5 *  (c) 1996  Hans-Joachim Widmaier - Rewritten
   6 *
   7 *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
   8 *
   9 *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
  10 *
  11 *  (C) 1991  Linus Torvalds - minix filesystem
  12 *
  13 *  affs regular file handling primitives
  14 */
  15
  16#include <linux/uio.h>
  17#include <linux/blkdev.h>
 
  18#include "affs.h"
  19
  20static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
  21
  22static int
  23affs_file_open(struct inode *inode, struct file *filp)
  24{
  25	pr_debug("open(%lu,%d)\n",
  26		 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  27	atomic_inc(&AFFS_I(inode)->i_opencnt);
  28	return 0;
  29}
  30
  31static int
  32affs_file_release(struct inode *inode, struct file *filp)
  33{
  34	pr_debug("release(%lu, %d)\n",
  35		 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  36
  37	if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
  38		inode_lock(inode);
  39		if (inode->i_size != AFFS_I(inode)->mmu_private)
  40			affs_truncate(inode);
  41		affs_free_prealloc(inode);
  42		inode_unlock(inode);
  43	}
  44
  45	return 0;
  46}
  47
  48static int
  49affs_grow_extcache(struct inode *inode, u32 lc_idx)
  50{
  51	struct super_block	*sb = inode->i_sb;
  52	struct buffer_head	*bh;
  53	u32 lc_max;
  54	int i, j, key;
  55
  56	if (!AFFS_I(inode)->i_lc) {
  57		char *ptr = (char *)get_zeroed_page(GFP_NOFS);
  58		if (!ptr)
  59			return -ENOMEM;
  60		AFFS_I(inode)->i_lc = (u32 *)ptr;
  61		AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
  62	}
  63
  64	lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
  65
  66	if (AFFS_I(inode)->i_extcnt > lc_max) {
  67		u32 lc_shift, lc_mask, tmp, off;
  68
  69		/* need to recalculate linear cache, start from old size */
  70		lc_shift = AFFS_I(inode)->i_lc_shift;
  71		tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
  72		for (; tmp; tmp >>= 1)
  73			lc_shift++;
  74		lc_mask = (1 << lc_shift) - 1;
  75
  76		/* fix idx and old size to new shift */
  77		lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  78		AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  79
  80		/* first shrink old cache to make more space */
  81		off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
  82		for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
  83			AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
  84
  85		AFFS_I(inode)->i_lc_shift = lc_shift;
  86		AFFS_I(inode)->i_lc_mask = lc_mask;
  87	}
  88
  89	/* fill cache to the needed index */
  90	i = AFFS_I(inode)->i_lc_size;
  91	AFFS_I(inode)->i_lc_size = lc_idx + 1;
  92	for (; i <= lc_idx; i++) {
  93		if (!i) {
  94			AFFS_I(inode)->i_lc[0] = inode->i_ino;
  95			continue;
  96		}
  97		key = AFFS_I(inode)->i_lc[i - 1];
  98		j = AFFS_I(inode)->i_lc_mask + 1;
  99		// unlock cache
 100		for (; j > 0; j--) {
 101			bh = affs_bread(sb, key);
 102			if (!bh)
 103				goto err;
 104			key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 105			affs_brelse(bh);
 106		}
 107		// lock cache
 108		AFFS_I(inode)->i_lc[i] = key;
 109	}
 110
 111	return 0;
 112
 113err:
 114	// lock cache
 115	return -EIO;
 116}
 117
 118static struct buffer_head *
 119affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
 120{
 121	struct super_block *sb = inode->i_sb;
 122	struct buffer_head *new_bh;
 123	u32 blocknr, tmp;
 124
 125	blocknr = affs_alloc_block(inode, bh->b_blocknr);
 126	if (!blocknr)
 127		return ERR_PTR(-ENOSPC);
 128
 129	new_bh = affs_getzeroblk(sb, blocknr);
 130	if (!new_bh) {
 131		affs_free_block(sb, blocknr);
 132		return ERR_PTR(-EIO);
 133	}
 134
 135	AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
 136	AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
 137	AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
 138	AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
 139	affs_fix_checksum(sb, new_bh);
 140
 141	mark_buffer_dirty_inode(new_bh, inode);
 142
 143	tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 144	if (tmp)
 145		affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
 146	AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
 147	affs_adjust_checksum(bh, blocknr - tmp);
 148	mark_buffer_dirty_inode(bh, inode);
 149
 150	AFFS_I(inode)->i_extcnt++;
 151	mark_inode_dirty(inode);
 152
 153	return new_bh;
 154}
 155
 156static inline struct buffer_head *
 157affs_get_extblock(struct inode *inode, u32 ext)
 158{
 159	/* inline the simplest case: same extended block as last time */
 160	struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
 161	if (ext == AFFS_I(inode)->i_ext_last)
 162		get_bh(bh);
 163	else
 164		/* we have to do more (not inlined) */
 165		bh = affs_get_extblock_slow(inode, ext);
 166
 167	return bh;
 168}
 169
 170static struct buffer_head *
 171affs_get_extblock_slow(struct inode *inode, u32 ext)
 172{
 173	struct super_block *sb = inode->i_sb;
 174	struct buffer_head *bh;
 175	u32 ext_key;
 176	u32 lc_idx, lc_off, ac_idx;
 177	u32 tmp, idx;
 178
 179	if (ext == AFFS_I(inode)->i_ext_last + 1) {
 180		/* read the next extended block from the current one */
 181		bh = AFFS_I(inode)->i_ext_bh;
 182		ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 183		if (ext < AFFS_I(inode)->i_extcnt)
 184			goto read_ext;
 185		BUG_ON(ext > AFFS_I(inode)->i_extcnt);
 186		bh = affs_alloc_extblock(inode, bh, ext);
 187		if (IS_ERR(bh))
 188			return bh;
 189		goto store_ext;
 190	}
 191
 192	if (ext == 0) {
 193		/* we seek back to the file header block */
 194		ext_key = inode->i_ino;
 195		goto read_ext;
 196	}
 197
 198	if (ext >= AFFS_I(inode)->i_extcnt) {
 199		struct buffer_head *prev_bh;
 200
 201		/* allocate a new extended block */
 202		BUG_ON(ext > AFFS_I(inode)->i_extcnt);
 203
 204		/* get previous extended block */
 205		prev_bh = affs_get_extblock(inode, ext - 1);
 206		if (IS_ERR(prev_bh))
 207			return prev_bh;
 208		bh = affs_alloc_extblock(inode, prev_bh, ext);
 209		affs_brelse(prev_bh);
 210		if (IS_ERR(bh))
 211			return bh;
 212		goto store_ext;
 213	}
 214
 215again:
 216	/* check if there is an extended cache and whether it's large enough */
 217	lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
 218	lc_off = ext & AFFS_I(inode)->i_lc_mask;
 219
 220	if (lc_idx >= AFFS_I(inode)->i_lc_size) {
 221		int err;
 222
 223		err = affs_grow_extcache(inode, lc_idx);
 224		if (err)
 225			return ERR_PTR(err);
 226		goto again;
 227	}
 228
 229	/* every n'th key we find in the linear cache */
 230	if (!lc_off) {
 231		ext_key = AFFS_I(inode)->i_lc[lc_idx];
 232		goto read_ext;
 233	}
 234
 235	/* maybe it's still in the associative cache */
 236	ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
 237	if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
 238		ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
 239		goto read_ext;
 240	}
 241
 242	/* try to find one of the previous extended blocks */
 243	tmp = ext;
 244	idx = ac_idx;
 245	while (--tmp, --lc_off > 0) {
 246		idx = (idx - 1) & AFFS_AC_MASK;
 247		if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
 248			ext_key = AFFS_I(inode)->i_ac[idx].key;
 249			goto find_ext;
 250		}
 251	}
 252
 253	/* fall back to the linear cache */
 254	ext_key = AFFS_I(inode)->i_lc[lc_idx];
 255find_ext:
 256	/* read all extended blocks until we find the one we need */
 257	//unlock cache
 258	do {
 259		bh = affs_bread(sb, ext_key);
 260		if (!bh)
 261			goto err_bread;
 262		ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 263		affs_brelse(bh);
 264		tmp++;
 265	} while (tmp < ext);
 266	//lock cache
 267
 268	/* store it in the associative cache */
 269	// recalculate ac_idx?
 270	AFFS_I(inode)->i_ac[ac_idx].ext = ext;
 271	AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
 272
 273read_ext:
 274	/* finally read the right extended block */
 275	//unlock cache
 276	bh = affs_bread(sb, ext_key);
 277	if (!bh)
 278		goto err_bread;
 279	//lock cache
 280
 281store_ext:
 282	/* release old cached extended block and store the new one */
 283	affs_brelse(AFFS_I(inode)->i_ext_bh);
 284	AFFS_I(inode)->i_ext_last = ext;
 285	AFFS_I(inode)->i_ext_bh = bh;
 286	get_bh(bh);
 287
 288	return bh;
 289
 290err_bread:
 291	affs_brelse(bh);
 292	return ERR_PTR(-EIO);
 293}
 294
 295static int
 296affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
 297{
 298	struct super_block	*sb = inode->i_sb;
 299	struct buffer_head	*ext_bh;
 300	u32			 ext;
 301
 302	pr_debug("%s(%lu, %llu)\n", __func__, inode->i_ino,
 303		 (unsigned long long)block);
 304
 305	BUG_ON(block > (sector_t)0x7fffffffUL);
 306
 307	if (block >= AFFS_I(inode)->i_blkcnt) {
 308		if (block > AFFS_I(inode)->i_blkcnt || !create)
 309			goto err_big;
 310	} else
 311		create = 0;
 312
 313	//lock cache
 314	affs_lock_ext(inode);
 315
 316	ext = (u32)block / AFFS_SB(sb)->s_hashsize;
 317	block -= ext * AFFS_SB(sb)->s_hashsize;
 318	ext_bh = affs_get_extblock(inode, ext);
 319	if (IS_ERR(ext_bh))
 320		goto err_ext;
 321	map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
 322
 323	if (create) {
 324		u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
 325		if (!blocknr)
 326			goto err_alloc;
 327		set_buffer_new(bh_result);
 328		AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
 329		AFFS_I(inode)->i_blkcnt++;
 330
 331		/* store new block */
 332		if (bh_result->b_blocknr)
 333			affs_warning(sb, "get_block",
 334				     "block already set (%llx)",
 335				     (unsigned long long)bh_result->b_blocknr);
 336		AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
 337		AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
 338		affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
 339		bh_result->b_blocknr = blocknr;
 340
 341		if (!block) {
 342			/* insert first block into header block */
 343			u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
 344			if (tmp)
 345				affs_warning(sb, "get_block", "first block already set (%d)", tmp);
 346			AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
 347			affs_adjust_checksum(ext_bh, blocknr - tmp);
 348		}
 349	}
 350
 351	affs_brelse(ext_bh);
 352	//unlock cache
 353	affs_unlock_ext(inode);
 354	return 0;
 355
 356err_big:
 357	affs_error(inode->i_sb, "get_block", "strange block request %llu",
 358		   (unsigned long long)block);
 359	return -EIO;
 360err_ext:
 361	// unlock cache
 362	affs_unlock_ext(inode);
 363	return PTR_ERR(ext_bh);
 364err_alloc:
 365	brelse(ext_bh);
 366	clear_buffer_mapped(bh_result);
 367	bh_result->b_bdev = NULL;
 368	// unlock cache
 369	affs_unlock_ext(inode);
 370	return -ENOSPC;
 371}
 372
 373static int affs_writepage(struct page *page, struct writeback_control *wbc)
 
 374{
 375	return block_write_full_page(page, affs_get_block, wbc);
 376}
 377
 378static int affs_readpage(struct file *file, struct page *page)
 379{
 380	return block_read_full_page(page, affs_get_block);
 381}
 382
 383static void affs_write_failed(struct address_space *mapping, loff_t to)
 384{
 385	struct inode *inode = mapping->host;
 386
 387	if (to > inode->i_size) {
 388		truncate_pagecache(inode, inode->i_size);
 389		affs_truncate(inode);
 390	}
 391}
 392
 393static ssize_t
 394affs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 395{
 396	struct file *file = iocb->ki_filp;
 397	struct address_space *mapping = file->f_mapping;
 398	struct inode *inode = mapping->host;
 399	size_t count = iov_iter_count(iter);
 400	loff_t offset = iocb->ki_pos;
 401	ssize_t ret;
 402
 403	if (iov_iter_rw(iter) == WRITE) {
 404		loff_t size = offset + count;
 405
 406		if (AFFS_I(inode)->mmu_private < size)
 407			return 0;
 408	}
 409
 410	ret = blockdev_direct_IO(iocb, inode, iter, affs_get_block);
 411	if (ret < 0 && iov_iter_rw(iter) == WRITE)
 412		affs_write_failed(mapping, offset + count);
 413	return ret;
 414}
 415
 416static int affs_write_begin(struct file *file, struct address_space *mapping,
 417			loff_t pos, unsigned len, unsigned flags,
 418			struct page **pagep, void **fsdata)
 419{
 420	int ret;
 421
 422	*pagep = NULL;
 423	ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 424				affs_get_block,
 425				&AFFS_I(mapping->host)->mmu_private);
 426	if (unlikely(ret))
 427		affs_write_failed(mapping, pos + len);
 428
 429	return ret;
 430}
 431
 432static int affs_write_end(struct file *file, struct address_space *mapping,
 433			  loff_t pos, unsigned int len, unsigned int copied,
 434			  struct page *page, void *fsdata)
 435{
 436	struct inode *inode = mapping->host;
 437	int ret;
 438
 439	ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
 440
 441	/* Clear Archived bit on file writes, as AmigaOS would do */
 442	if (AFFS_I(inode)->i_protect & FIBF_ARCHIVED) {
 443		AFFS_I(inode)->i_protect &= ~FIBF_ARCHIVED;
 444		mark_inode_dirty(inode);
 445	}
 446
 447	return ret;
 448}
 449
 450static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 451{
 452	return generic_block_bmap(mapping,block,affs_get_block);
 453}
 454
 455const struct address_space_operations affs_aops = {
 456	.readpage = affs_readpage,
 457	.writepage = affs_writepage,
 
 
 458	.write_begin = affs_write_begin,
 459	.write_end = affs_write_end,
 460	.direct_IO = affs_direct_IO,
 
 461	.bmap = _affs_bmap
 462};
 463
 464static inline struct buffer_head *
 465affs_bread_ino(struct inode *inode, int block, int create)
 466{
 467	struct buffer_head *bh, tmp_bh;
 468	int err;
 469
 470	tmp_bh.b_state = 0;
 471	err = affs_get_block(inode, block, &tmp_bh, create);
 472	if (!err) {
 473		bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
 474		if (bh) {
 475			bh->b_state |= tmp_bh.b_state;
 476			return bh;
 477		}
 478		err = -EIO;
 479	}
 480	return ERR_PTR(err);
 481}
 482
 483static inline struct buffer_head *
 484affs_getzeroblk_ino(struct inode *inode, int block)
 485{
 486	struct buffer_head *bh, tmp_bh;
 487	int err;
 488
 489	tmp_bh.b_state = 0;
 490	err = affs_get_block(inode, block, &tmp_bh, 1);
 491	if (!err) {
 492		bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
 493		if (bh) {
 494			bh->b_state |= tmp_bh.b_state;
 495			return bh;
 496		}
 497		err = -EIO;
 498	}
 499	return ERR_PTR(err);
 500}
 501
 502static inline struct buffer_head *
 503affs_getemptyblk_ino(struct inode *inode, int block)
 504{
 505	struct buffer_head *bh, tmp_bh;
 506	int err;
 507
 508	tmp_bh.b_state = 0;
 509	err = affs_get_block(inode, block, &tmp_bh, 1);
 510	if (!err) {
 511		bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
 512		if (bh) {
 513			bh->b_state |= tmp_bh.b_state;
 514			return bh;
 515		}
 516		err = -EIO;
 517	}
 518	return ERR_PTR(err);
 519}
 520
 521static int
 522affs_do_readpage_ofs(struct page *page, unsigned to, int create)
 523{
 524	struct inode *inode = page->mapping->host;
 525	struct super_block *sb = inode->i_sb;
 526	struct buffer_head *bh;
 527	char *data;
 528	unsigned pos = 0;
 529	u32 bidx, boff, bsize;
 530	u32 tmp;
 531
 532	pr_debug("%s(%lu, %ld, 0, %d)\n", __func__, inode->i_ino,
 533		 page->index, to);
 534	BUG_ON(to > PAGE_SIZE);
 535	bsize = AFFS_SB(sb)->s_data_blksize;
 536	tmp = page->index << PAGE_SHIFT;
 537	bidx = tmp / bsize;
 538	boff = tmp % bsize;
 539
 540	while (pos < to) {
 541		bh = affs_bread_ino(inode, bidx, create);
 542		if (IS_ERR(bh))
 543			return PTR_ERR(bh);
 544		tmp = min(bsize - boff, to - pos);
 545		BUG_ON(pos + tmp > to || tmp > bsize);
 546		data = kmap_atomic(page);
 547		memcpy(data + pos, AFFS_DATA(bh) + boff, tmp);
 548		kunmap_atomic(data);
 549		affs_brelse(bh);
 550		bidx++;
 551		pos += tmp;
 552		boff = 0;
 553	}
 554	flush_dcache_page(page);
 555	return 0;
 556}
 557
 558static int
 559affs_extent_file_ofs(struct inode *inode, u32 newsize)
 560{
 561	struct super_block *sb = inode->i_sb;
 562	struct buffer_head *bh, *prev_bh;
 563	u32 bidx, boff;
 564	u32 size, bsize;
 565	u32 tmp;
 566
 567	pr_debug("%s(%lu, %d)\n", __func__, inode->i_ino, newsize);
 568	bsize = AFFS_SB(sb)->s_data_blksize;
 569	bh = NULL;
 570	size = AFFS_I(inode)->mmu_private;
 571	bidx = size / bsize;
 572	boff = size % bsize;
 573	if (boff) {
 574		bh = affs_bread_ino(inode, bidx, 0);
 575		if (IS_ERR(bh))
 576			return PTR_ERR(bh);
 577		tmp = min(bsize - boff, newsize - size);
 578		BUG_ON(boff + tmp > bsize || tmp > bsize);
 579		memset(AFFS_DATA(bh) + boff, 0, tmp);
 580		be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 581		affs_fix_checksum(sb, bh);
 582		mark_buffer_dirty_inode(bh, inode);
 583		size += tmp;
 584		bidx++;
 585	} else if (bidx) {
 586		bh = affs_bread_ino(inode, bidx - 1, 0);
 587		if (IS_ERR(bh))
 588			return PTR_ERR(bh);
 589	}
 590
 591	while (size < newsize) {
 592		prev_bh = bh;
 593		bh = affs_getzeroblk_ino(inode, bidx);
 594		if (IS_ERR(bh))
 595			goto out;
 596		tmp = min(bsize, newsize - size);
 597		BUG_ON(tmp > bsize);
 598		AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 599		AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 600		AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 601		AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 602		affs_fix_checksum(sb, bh);
 603		bh->b_state &= ~(1UL << BH_New);
 604		mark_buffer_dirty_inode(bh, inode);
 605		if (prev_bh) {
 606			u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 607
 608			if (tmp_next)
 609				affs_warning(sb, "extent_file_ofs",
 610					     "next block already set for %d (%d)",
 611					     bidx, tmp_next);
 612			AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 613			affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 614			mark_buffer_dirty_inode(prev_bh, inode);
 615			affs_brelse(prev_bh);
 616		}
 617		size += bsize;
 618		bidx++;
 619	}
 620	affs_brelse(bh);
 621	inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 622	return 0;
 623
 624out:
 625	inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 626	return PTR_ERR(bh);
 627}
 628
 629static int
 630affs_readpage_ofs(struct file *file, struct page *page)
 631{
 632	struct inode *inode = page->mapping->host;
 633	u32 to;
 634	int err;
 635
 636	pr_debug("%s(%lu, %ld)\n", __func__, inode->i_ino, page->index);
 637	to = PAGE_SIZE;
 638	if (((page->index + 1) << PAGE_SHIFT) > inode->i_size) {
 639		to = inode->i_size & ~PAGE_MASK;
 640		memset(page_address(page) + to, 0, PAGE_SIZE - to);
 641	}
 642
 643	err = affs_do_readpage_ofs(page, to, 0);
 644	if (!err)
 645		SetPageUptodate(page);
 646	unlock_page(page);
 647	return err;
 648}
 649
 650static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 651				loff_t pos, unsigned len, unsigned flags,
 652				struct page **pagep, void **fsdata)
 653{
 654	struct inode *inode = mapping->host;
 655	struct page *page;
 656	pgoff_t index;
 657	int err = 0;
 658
 659	pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 660		 pos + len);
 661	if (pos > AFFS_I(inode)->mmu_private) {
 662		/* XXX: this probably leaves a too-big i_size in case of
 663		 * failure. Should really be updating i_size at write_end time
 664		 */
 665		err = affs_extent_file_ofs(inode, pos);
 666		if (err)
 667			return err;
 668	}
 669
 670	index = pos >> PAGE_SHIFT;
 671	page = grab_cache_page_write_begin(mapping, index, flags);
 672	if (!page)
 673		return -ENOMEM;
 674	*pagep = page;
 
 675
 676	if (PageUptodate(page))
 677		return 0;
 678
 679	/* XXX: inefficient but safe in the face of short writes */
 680	err = affs_do_readpage_ofs(page, PAGE_SIZE, 1);
 681	if (err) {
 682		unlock_page(page);
 683		put_page(page);
 684	}
 685	return err;
 686}
 687
 688static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 689				loff_t pos, unsigned len, unsigned copied,
 690				struct page *page, void *fsdata)
 691{
 
 692	struct inode *inode = mapping->host;
 693	struct super_block *sb = inode->i_sb;
 694	struct buffer_head *bh, *prev_bh;
 695	char *data;
 696	u32 bidx, boff, bsize;
 697	unsigned from, to;
 698	u32 tmp;
 699	int written;
 700
 701	from = pos & (PAGE_SIZE - 1);
 702	to = from + len;
 703	/*
 704	 * XXX: not sure if this can handle short copies (len < copied), but
 705	 * we don't have to, because the page should always be uptodate here,
 706	 * due to write_begin.
 707	 */
 708
 709	pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 710		 pos + len);
 711	bsize = AFFS_SB(sb)->s_data_blksize;
 712	data = page_address(page);
 713
 714	bh = NULL;
 715	written = 0;
 716	tmp = (page->index << PAGE_SHIFT) + from;
 717	bidx = tmp / bsize;
 718	boff = tmp % bsize;
 719	if (boff) {
 720		bh = affs_bread_ino(inode, bidx, 0);
 721		if (IS_ERR(bh)) {
 722			written = PTR_ERR(bh);
 723			goto err_first_bh;
 724		}
 725		tmp = min(bsize - boff, to - from);
 726		BUG_ON(boff + tmp > bsize || tmp > bsize);
 727		memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 728		be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 729		affs_fix_checksum(sb, bh);
 730		mark_buffer_dirty_inode(bh, inode);
 731		written += tmp;
 732		from += tmp;
 733		bidx++;
 734	} else if (bidx) {
 735		bh = affs_bread_ino(inode, bidx - 1, 0);
 736		if (IS_ERR(bh)) {
 737			written = PTR_ERR(bh);
 738			goto err_first_bh;
 739		}
 740	}
 741	while (from + bsize <= to) {
 742		prev_bh = bh;
 743		bh = affs_getemptyblk_ino(inode, bidx);
 744		if (IS_ERR(bh))
 745			goto err_bh;
 746		memcpy(AFFS_DATA(bh), data + from, bsize);
 747		if (buffer_new(bh)) {
 748			AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 749			AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 750			AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 751			AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 752			AFFS_DATA_HEAD(bh)->next = 0;
 753			bh->b_state &= ~(1UL << BH_New);
 754			if (prev_bh) {
 755				u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 756
 757				if (tmp_next)
 758					affs_warning(sb, "commit_write_ofs",
 759						     "next block already set for %d (%d)",
 760						     bidx, tmp_next);
 761				AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 762				affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 763				mark_buffer_dirty_inode(prev_bh, inode);
 764			}
 765		}
 766		affs_brelse(prev_bh);
 767		affs_fix_checksum(sb, bh);
 768		mark_buffer_dirty_inode(bh, inode);
 769		written += bsize;
 770		from += bsize;
 771		bidx++;
 772	}
 773	if (from < to) {
 774		prev_bh = bh;
 775		bh = affs_bread_ino(inode, bidx, 1);
 776		if (IS_ERR(bh))
 777			goto err_bh;
 778		tmp = min(bsize, to - from);
 779		BUG_ON(tmp > bsize);
 780		memcpy(AFFS_DATA(bh), data + from, tmp);
 781		if (buffer_new(bh)) {
 782			AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 783			AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 784			AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 785			AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 786			AFFS_DATA_HEAD(bh)->next = 0;
 787			bh->b_state &= ~(1UL << BH_New);
 788			if (prev_bh) {
 789				u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 790
 791				if (tmp_next)
 792					affs_warning(sb, "commit_write_ofs",
 793						     "next block already set for %d (%d)",
 794						     bidx, tmp_next);
 795				AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 796				affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 797				mark_buffer_dirty_inode(prev_bh, inode);
 798			}
 799		} else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 800			AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 801		affs_brelse(prev_bh);
 802		affs_fix_checksum(sb, bh);
 803		mark_buffer_dirty_inode(bh, inode);
 804		written += tmp;
 805		from += tmp;
 806		bidx++;
 807	}
 808	SetPageUptodate(page);
 809
 810done:
 811	affs_brelse(bh);
 812	tmp = (page->index << PAGE_SHIFT) + from;
 813	if (tmp > inode->i_size)
 814		inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 815
 816	/* Clear Archived bit on file writes, as AmigaOS would do */
 817	if (AFFS_I(inode)->i_protect & FIBF_ARCHIVED) {
 818		AFFS_I(inode)->i_protect &= ~FIBF_ARCHIVED;
 819		mark_inode_dirty(inode);
 820	}
 821
 822err_first_bh:
 823	unlock_page(page);
 824	put_page(page);
 825
 826	return written;
 827
 828err_bh:
 829	bh = prev_bh;
 830	if (!written)
 831		written = PTR_ERR(bh);
 832	goto done;
 833}
 834
 835const struct address_space_operations affs_aops_ofs = {
 836	.readpage = affs_readpage_ofs,
 837	//.writepage = affs_writepage_ofs,
 
 
 838	.write_begin = affs_write_begin_ofs,
 839	.write_end = affs_write_end_ofs
 
 840};
 841
 842/* Free any preallocated blocks. */
 843
 844void
 845affs_free_prealloc(struct inode *inode)
 846{
 847	struct super_block *sb = inode->i_sb;
 848
 849	pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
 850
 851	while (AFFS_I(inode)->i_pa_cnt) {
 852		AFFS_I(inode)->i_pa_cnt--;
 853		affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 854	}
 855}
 856
 857/* Truncate (or enlarge) a file to the requested size. */
 858
 859void
 860affs_truncate(struct inode *inode)
 861{
 862	struct super_block *sb = inode->i_sb;
 863	u32 ext, ext_key;
 864	u32 last_blk, blkcnt, blk;
 865	u32 size;
 866	struct buffer_head *ext_bh;
 867	int i;
 868
 869	pr_debug("truncate(inode=%lu, oldsize=%llu, newsize=%llu)\n",
 870		 inode->i_ino, AFFS_I(inode)->mmu_private, inode->i_size);
 871
 872	last_blk = 0;
 873	ext = 0;
 874	if (inode->i_size) {
 875		last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 876		ext = last_blk / AFFS_SB(sb)->s_hashsize;
 877	}
 878
 879	if (inode->i_size > AFFS_I(inode)->mmu_private) {
 880		struct address_space *mapping = inode->i_mapping;
 881		struct page *page;
 882		void *fsdata;
 883		loff_t isize = inode->i_size;
 884		int res;
 885
 886		res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, 0, &page, &fsdata);
 887		if (!res)
 888			res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
 889		else
 890			inode->i_size = AFFS_I(inode)->mmu_private;
 891		mark_inode_dirty(inode);
 892		return;
 893	} else if (inode->i_size == AFFS_I(inode)->mmu_private)
 894		return;
 895
 896	// lock cache
 897	ext_bh = affs_get_extblock(inode, ext);
 898	if (IS_ERR(ext_bh)) {
 899		affs_warning(sb, "truncate",
 900			     "unexpected read error for ext block %u (%ld)",
 901			     ext, PTR_ERR(ext_bh));
 902		return;
 903	}
 904	if (AFFS_I(inode)->i_lc) {
 905		/* clear linear cache */
 906		i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 907		if (AFFS_I(inode)->i_lc_size > i) {
 908			AFFS_I(inode)->i_lc_size = i;
 909			for (; i < AFFS_LC_SIZE; i++)
 910				AFFS_I(inode)->i_lc[i] = 0;
 911		}
 912		/* clear associative cache */
 913		for (i = 0; i < AFFS_AC_SIZE; i++)
 914			if (AFFS_I(inode)->i_ac[i].ext >= ext)
 915				AFFS_I(inode)->i_ac[i].ext = 0;
 916	}
 917	ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 918
 919	blkcnt = AFFS_I(inode)->i_blkcnt;
 920	i = 0;
 921	blk = last_blk;
 922	if (inode->i_size) {
 923		i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 924		blk++;
 925	} else
 926		AFFS_HEAD(ext_bh)->first_data = 0;
 927	AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 928	size = AFFS_SB(sb)->s_hashsize;
 929	if (size > blkcnt - blk + i)
 930		size = blkcnt - blk + i;
 931	for (; i < size; i++, blk++) {
 932		affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 933		AFFS_BLOCK(sb, ext_bh, i) = 0;
 934	}
 935	AFFS_TAIL(sb, ext_bh)->extension = 0;
 936	affs_fix_checksum(sb, ext_bh);
 937	mark_buffer_dirty_inode(ext_bh, inode);
 938	affs_brelse(ext_bh);
 939
 940	if (inode->i_size) {
 941		AFFS_I(inode)->i_blkcnt = last_blk + 1;
 942		AFFS_I(inode)->i_extcnt = ext + 1;
 943		if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS)) {
 944			struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 945			u32 tmp;
 946			if (IS_ERR(bh)) {
 947				affs_warning(sb, "truncate",
 948					     "unexpected read error for last block %u (%ld)",
 949					     ext, PTR_ERR(bh));
 950				return;
 951			}
 952			tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 953			AFFS_DATA_HEAD(bh)->next = 0;
 954			affs_adjust_checksum(bh, -tmp);
 955			affs_brelse(bh);
 956		}
 957	} else {
 958		AFFS_I(inode)->i_blkcnt = 0;
 959		AFFS_I(inode)->i_extcnt = 1;
 960	}
 961	AFFS_I(inode)->mmu_private = inode->i_size;
 962	// unlock cache
 963
 964	while (ext_key) {
 965		ext_bh = affs_bread(sb, ext_key);
 966		size = AFFS_SB(sb)->s_hashsize;
 967		if (size > blkcnt - blk)
 968			size = blkcnt - blk;
 969		for (i = 0; i < size; i++, blk++)
 970			affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 971		affs_free_block(sb, ext_key);
 972		ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 973		affs_brelse(ext_bh);
 974	}
 975	affs_free_prealloc(inode);
 976}
 977
 978int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 979{
 980	struct inode *inode = filp->f_mapping->host;
 981	int ret, err;
 982
 983	err = file_write_and_wait_range(filp, start, end);
 984	if (err)
 985		return err;
 986
 987	inode_lock(inode);
 988	ret = write_inode_now(inode, 0);
 989	err = sync_blockdev(inode->i_sb->s_bdev);
 990	if (!ret)
 991		ret = err;
 992	inode_unlock(inode);
 993	return ret;
 994}
 995const struct file_operations affs_file_operations = {
 996	.llseek		= generic_file_llseek,
 997	.read_iter	= generic_file_read_iter,
 998	.write_iter	= generic_file_write_iter,
 999	.mmap		= generic_file_mmap,
1000	.open		= affs_file_open,
1001	.release	= affs_file_release,
1002	.fsync		= affs_file_fsync,
1003	.splice_read	= generic_file_splice_read,
1004};
1005
1006const struct inode_operations affs_file_inode_operations = {
1007	.setattr	= affs_notify_change,
1008};