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v6.2
   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * NILFS checkpoint file.
   4 *
   5 * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
   6 *
   7 * Written by Koji Sato.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   8 */
   9
  10#include <linux/kernel.h>
  11#include <linux/fs.h>
  12#include <linux/string.h>
  13#include <linux/buffer_head.h>
  14#include <linux/errno.h>
 
  15#include "mdt.h"
  16#include "cpfile.h"
  17
  18
  19static inline unsigned long
  20nilfs_cpfile_checkpoints_per_block(const struct inode *cpfile)
  21{
  22	return NILFS_MDT(cpfile)->mi_entries_per_block;
  23}
  24
  25/* block number from the beginning of the file */
  26static unsigned long
  27nilfs_cpfile_get_blkoff(const struct inode *cpfile, __u64 cno)
  28{
  29	__u64 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
  30
  31	do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile));
  32	return (unsigned long)tcno;
  33}
  34
  35/* offset in block */
  36static unsigned long
  37nilfs_cpfile_get_offset(const struct inode *cpfile, __u64 cno)
  38{
  39	__u64 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
  40
  41	return do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile));
  42}
  43
  44static __u64 nilfs_cpfile_first_checkpoint_in_block(const struct inode *cpfile,
  45						    unsigned long blkoff)
  46{
  47	return (__u64)nilfs_cpfile_checkpoints_per_block(cpfile) * blkoff
  48		+ 1 - NILFS_MDT(cpfile)->mi_first_entry_offset;
  49}
  50
  51static unsigned long
  52nilfs_cpfile_checkpoints_in_block(const struct inode *cpfile,
  53				  __u64 curr,
  54				  __u64 max)
  55{
  56	return min_t(__u64,
  57		     nilfs_cpfile_checkpoints_per_block(cpfile) -
  58		     nilfs_cpfile_get_offset(cpfile, curr),
  59		     max - curr);
  60}
  61
  62static inline int nilfs_cpfile_is_in_first(const struct inode *cpfile,
  63					   __u64 cno)
  64{
  65	return nilfs_cpfile_get_blkoff(cpfile, cno) == 0;
  66}
  67
  68static unsigned int
  69nilfs_cpfile_block_add_valid_checkpoints(const struct inode *cpfile,
  70					 struct buffer_head *bh,
  71					 void *kaddr,
  72					 unsigned int n)
  73{
  74	struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
  75	unsigned int count;
  76
  77	count = le32_to_cpu(cp->cp_checkpoints_count) + n;
  78	cp->cp_checkpoints_count = cpu_to_le32(count);
  79	return count;
  80}
  81
  82static unsigned int
  83nilfs_cpfile_block_sub_valid_checkpoints(const struct inode *cpfile,
  84					 struct buffer_head *bh,
  85					 void *kaddr,
  86					 unsigned int n)
  87{
  88	struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
  89	unsigned int count;
  90
  91	WARN_ON(le32_to_cpu(cp->cp_checkpoints_count) < n);
  92	count = le32_to_cpu(cp->cp_checkpoints_count) - n;
  93	cp->cp_checkpoints_count = cpu_to_le32(count);
  94	return count;
  95}
  96
  97static inline struct nilfs_cpfile_header *
  98nilfs_cpfile_block_get_header(const struct inode *cpfile,
  99			      struct buffer_head *bh,
 100			      void *kaddr)
 101{
 102	return kaddr + bh_offset(bh);
 103}
 104
 105static struct nilfs_checkpoint *
 106nilfs_cpfile_block_get_checkpoint(const struct inode *cpfile, __u64 cno,
 107				  struct buffer_head *bh,
 108				  void *kaddr)
 109{
 110	return kaddr + bh_offset(bh) + nilfs_cpfile_get_offset(cpfile, cno) *
 111		NILFS_MDT(cpfile)->mi_entry_size;
 112}
 113
 114static void nilfs_cpfile_block_init(struct inode *cpfile,
 115				    struct buffer_head *bh,
 116				    void *kaddr)
 117{
 118	struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
 119	size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
 120	int n = nilfs_cpfile_checkpoints_per_block(cpfile);
 121
 122	while (n-- > 0) {
 123		nilfs_checkpoint_set_invalid(cp);
 124		cp = (void *)cp + cpsz;
 125	}
 126}
 127
 128static inline int nilfs_cpfile_get_header_block(struct inode *cpfile,
 129						struct buffer_head **bhp)
 130{
 131	return nilfs_mdt_get_block(cpfile, 0, 0, NULL, bhp);
 132}
 133
 134static inline int nilfs_cpfile_get_checkpoint_block(struct inode *cpfile,
 135						    __u64 cno,
 136						    int create,
 137						    struct buffer_head **bhp)
 138{
 139	return nilfs_mdt_get_block(cpfile,
 140				   nilfs_cpfile_get_blkoff(cpfile, cno),
 141				   create, nilfs_cpfile_block_init, bhp);
 142}
 143
 144/**
 145 * nilfs_cpfile_find_checkpoint_block - find and get a buffer on cpfile
 146 * @cpfile: inode of cpfile
 147 * @start_cno: start checkpoint number (inclusive)
 148 * @end_cno: end checkpoint number (inclusive)
 149 * @cnop: place to store the next checkpoint number
 150 * @bhp: place to store a pointer to buffer_head struct
 151 *
 152 * Return Value: On success, it returns 0. On error, the following negative
 153 * error code is returned.
 154 *
 155 * %-ENOMEM - Insufficient memory available.
 156 *
 157 * %-EIO - I/O error
 158 *
 159 * %-ENOENT - no block exists in the range.
 160 */
 161static int nilfs_cpfile_find_checkpoint_block(struct inode *cpfile,
 162					      __u64 start_cno, __u64 end_cno,
 163					      __u64 *cnop,
 164					      struct buffer_head **bhp)
 165{
 166	unsigned long start, end, blkoff;
 167	int ret;
 168
 169	if (unlikely(start_cno > end_cno))
 170		return -ENOENT;
 171
 172	start = nilfs_cpfile_get_blkoff(cpfile, start_cno);
 173	end = nilfs_cpfile_get_blkoff(cpfile, end_cno);
 174
 175	ret = nilfs_mdt_find_block(cpfile, start, end, &blkoff, bhp);
 176	if (!ret)
 177		*cnop = (blkoff == start) ? start_cno :
 178			nilfs_cpfile_first_checkpoint_in_block(cpfile, blkoff);
 179	return ret;
 180}
 181
 182static inline int nilfs_cpfile_delete_checkpoint_block(struct inode *cpfile,
 183						       __u64 cno)
 184{
 185	return nilfs_mdt_delete_block(cpfile,
 186				      nilfs_cpfile_get_blkoff(cpfile, cno));
 187}
 188
 189/**
 190 * nilfs_cpfile_get_checkpoint - get a checkpoint
 191 * @cpfile: inode of checkpoint file
 192 * @cno: checkpoint number
 193 * @create: create flag
 194 * @cpp: pointer to a checkpoint
 195 * @bhp: pointer to a buffer head
 196 *
 197 * Description: nilfs_cpfile_get_checkpoint() acquires the checkpoint
 198 * specified by @cno. A new checkpoint will be created if @cno is the current
 199 * checkpoint number and @create is nonzero.
 200 *
 201 * Return Value: On success, 0 is returned, and the checkpoint and the
 202 * buffer head of the buffer on which the checkpoint is located are stored in
 203 * the place pointed by @cpp and @bhp, respectively. On error, one of the
 204 * following negative error codes is returned.
 205 *
 206 * %-EIO - I/O error.
 207 *
 208 * %-ENOMEM - Insufficient amount of memory available.
 209 *
 210 * %-ENOENT - No such checkpoint.
 211 *
 212 * %-EINVAL - invalid checkpoint.
 213 */
 214int nilfs_cpfile_get_checkpoint(struct inode *cpfile,
 215				__u64 cno,
 216				int create,
 217				struct nilfs_checkpoint **cpp,
 218				struct buffer_head **bhp)
 219{
 220	struct buffer_head *header_bh, *cp_bh;
 221	struct nilfs_cpfile_header *header;
 222	struct nilfs_checkpoint *cp;
 223	void *kaddr;
 224	int ret;
 225
 226	if (unlikely(cno < 1 || cno > nilfs_mdt_cno(cpfile) ||
 227		     (cno < nilfs_mdt_cno(cpfile) && create)))
 228		return -EINVAL;
 229
 230	down_write(&NILFS_MDT(cpfile)->mi_sem);
 231
 232	ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
 233	if (ret < 0)
 234		goto out_sem;
 235	ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, create, &cp_bh);
 236	if (ret < 0)
 237		goto out_header;
 238	kaddr = kmap(cp_bh->b_page);
 239	cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
 240	if (nilfs_checkpoint_invalid(cp)) {
 241		if (!create) {
 242			kunmap(cp_bh->b_page);
 243			brelse(cp_bh);
 244			ret = -ENOENT;
 245			goto out_header;
 246		}
 247		/* a newly-created checkpoint */
 248		nilfs_checkpoint_clear_invalid(cp);
 249		if (!nilfs_cpfile_is_in_first(cpfile, cno))
 250			nilfs_cpfile_block_add_valid_checkpoints(cpfile, cp_bh,
 251								 kaddr, 1);
 252		mark_buffer_dirty(cp_bh);
 253
 254		kaddr = kmap_atomic(header_bh->b_page);
 255		header = nilfs_cpfile_block_get_header(cpfile, header_bh,
 256						       kaddr);
 257		le64_add_cpu(&header->ch_ncheckpoints, 1);
 258		kunmap_atomic(kaddr);
 259		mark_buffer_dirty(header_bh);
 260		nilfs_mdt_mark_dirty(cpfile);
 261	}
 262
 263	if (cpp != NULL)
 264		*cpp = cp;
 265	*bhp = cp_bh;
 266
 267 out_header:
 268	brelse(header_bh);
 269
 270 out_sem:
 271	up_write(&NILFS_MDT(cpfile)->mi_sem);
 272	return ret;
 273}
 274
 275/**
 276 * nilfs_cpfile_put_checkpoint - put a checkpoint
 277 * @cpfile: inode of checkpoint file
 278 * @cno: checkpoint number
 279 * @bh: buffer head
 280 *
 281 * Description: nilfs_cpfile_put_checkpoint() releases the checkpoint
 282 * specified by @cno. @bh must be the buffer head which has been returned by
 283 * a previous call to nilfs_cpfile_get_checkpoint() with @cno.
 284 */
 285void nilfs_cpfile_put_checkpoint(struct inode *cpfile, __u64 cno,
 286				 struct buffer_head *bh)
 287{
 288	kunmap(bh->b_page);
 289	brelse(bh);
 290}
 291
 292/**
 293 * nilfs_cpfile_delete_checkpoints - delete checkpoints
 294 * @cpfile: inode of checkpoint file
 295 * @start: start checkpoint number
 296 * @end: end checkpoint number
 297 *
 298 * Description: nilfs_cpfile_delete_checkpoints() deletes the checkpoints in
 299 * the period from @start to @end, excluding @end itself. The checkpoints
 300 * which have been already deleted are ignored.
 301 *
 302 * Return Value: On success, 0 is returned. On error, one of the following
 303 * negative error codes is returned.
 304 *
 305 * %-EIO - I/O error.
 306 *
 307 * %-ENOMEM - Insufficient amount of memory available.
 308 *
 309 * %-EINVAL - invalid checkpoints.
 310 */
 311int nilfs_cpfile_delete_checkpoints(struct inode *cpfile,
 312				    __u64 start,
 313				    __u64 end)
 314{
 315	struct buffer_head *header_bh, *cp_bh;
 316	struct nilfs_cpfile_header *header;
 317	struct nilfs_checkpoint *cp;
 318	size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
 319	__u64 cno;
 320	void *kaddr;
 321	unsigned long tnicps;
 322	int ret, ncps, nicps, nss, count, i;
 323
 324	if (unlikely(start == 0 || start > end)) {
 325		nilfs_err(cpfile->i_sb,
 326			  "cannot delete checkpoints: invalid range [%llu, %llu)",
 327			  (unsigned long long)start, (unsigned long long)end);
 328		return -EINVAL;
 329	}
 330
 331	down_write(&NILFS_MDT(cpfile)->mi_sem);
 332
 333	ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
 334	if (ret < 0)
 335		goto out_sem;
 336	tnicps = 0;
 337	nss = 0;
 338
 339	for (cno = start; cno < end; cno += ncps) {
 340		ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, end);
 341		ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
 342		if (ret < 0) {
 343			if (ret != -ENOENT)
 344				break;
 345			/* skip hole */
 346			ret = 0;
 347			continue;
 348		}
 349
 350		kaddr = kmap_atomic(cp_bh->b_page);
 351		cp = nilfs_cpfile_block_get_checkpoint(
 352			cpfile, cno, cp_bh, kaddr);
 353		nicps = 0;
 354		for (i = 0; i < ncps; i++, cp = (void *)cp + cpsz) {
 355			if (nilfs_checkpoint_snapshot(cp)) {
 356				nss++;
 357			} else if (!nilfs_checkpoint_invalid(cp)) {
 358				nilfs_checkpoint_set_invalid(cp);
 359				nicps++;
 360			}
 361		}
 362		if (nicps > 0) {
 363			tnicps += nicps;
 364			mark_buffer_dirty(cp_bh);
 365			nilfs_mdt_mark_dirty(cpfile);
 366			if (!nilfs_cpfile_is_in_first(cpfile, cno)) {
 367				count =
 368				  nilfs_cpfile_block_sub_valid_checkpoints(
 369						cpfile, cp_bh, kaddr, nicps);
 370				if (count == 0) {
 371					/* make hole */
 372					kunmap_atomic(kaddr);
 373					brelse(cp_bh);
 374					ret =
 375					  nilfs_cpfile_delete_checkpoint_block(
 376								   cpfile, cno);
 377					if (ret == 0)
 378						continue;
 379					nilfs_err(cpfile->i_sb,
 380						  "error %d deleting checkpoint block",
 381						  ret);
 382					break;
 383				}
 384			}
 385		}
 386
 387		kunmap_atomic(kaddr);
 388		brelse(cp_bh);
 389	}
 390
 391	if (tnicps > 0) {
 392		kaddr = kmap_atomic(header_bh->b_page);
 393		header = nilfs_cpfile_block_get_header(cpfile, header_bh,
 394						       kaddr);
 395		le64_add_cpu(&header->ch_ncheckpoints, -(u64)tnicps);
 396		mark_buffer_dirty(header_bh);
 397		nilfs_mdt_mark_dirty(cpfile);
 398		kunmap_atomic(kaddr);
 399	}
 400
 401	brelse(header_bh);
 402	if (nss > 0)
 403		ret = -EBUSY;
 404
 405 out_sem:
 406	up_write(&NILFS_MDT(cpfile)->mi_sem);
 407	return ret;
 408}
 409
 410static void nilfs_cpfile_checkpoint_to_cpinfo(struct inode *cpfile,
 411					      struct nilfs_checkpoint *cp,
 412					      struct nilfs_cpinfo *ci)
 413{
 414	ci->ci_flags = le32_to_cpu(cp->cp_flags);
 415	ci->ci_cno = le64_to_cpu(cp->cp_cno);
 416	ci->ci_create = le64_to_cpu(cp->cp_create);
 417	ci->ci_nblk_inc = le64_to_cpu(cp->cp_nblk_inc);
 418	ci->ci_inodes_count = le64_to_cpu(cp->cp_inodes_count);
 419	ci->ci_blocks_count = le64_to_cpu(cp->cp_blocks_count);
 420	ci->ci_next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
 421}
 422
 423static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop,
 424					  void *buf, unsigned int cisz,
 425					  size_t nci)
 426{
 427	struct nilfs_checkpoint *cp;
 428	struct nilfs_cpinfo *ci = buf;
 429	struct buffer_head *bh;
 430	size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
 431	__u64 cur_cno = nilfs_mdt_cno(cpfile), cno = *cnop;
 432	void *kaddr;
 433	int n, ret;
 434	int ncps, i;
 435
 436	if (cno == 0)
 437		return -ENOENT; /* checkpoint number 0 is invalid */
 438	down_read(&NILFS_MDT(cpfile)->mi_sem);
 439
 440	for (n = 0; n < nci; cno += ncps) {
 441		ret = nilfs_cpfile_find_checkpoint_block(
 442			cpfile, cno, cur_cno - 1, &cno, &bh);
 443		if (ret < 0) {
 444			if (likely(ret == -ENOENT))
 445				break;
 446			goto out;
 447		}
 448		ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, cur_cno);
 449
 450		kaddr = kmap_atomic(bh->b_page);
 451		cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
 452		for (i = 0; i < ncps && n < nci; i++, cp = (void *)cp + cpsz) {
 453			if (!nilfs_checkpoint_invalid(cp)) {
 454				nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp,
 455								  ci);
 456				ci = (void *)ci + cisz;
 457				n++;
 458			}
 459		}
 460		kunmap_atomic(kaddr);
 461		brelse(bh);
 462	}
 463
 464	ret = n;
 465	if (n > 0) {
 466		ci = (void *)ci - cisz;
 467		*cnop = ci->ci_cno + 1;
 468	}
 469
 470 out:
 471	up_read(&NILFS_MDT(cpfile)->mi_sem);
 472	return ret;
 473}
 474
 475static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
 476					  void *buf, unsigned int cisz,
 477					  size_t nci)
 478{
 479	struct buffer_head *bh;
 480	struct nilfs_cpfile_header *header;
 481	struct nilfs_checkpoint *cp;
 482	struct nilfs_cpinfo *ci = buf;
 483	__u64 curr = *cnop, next;
 484	unsigned long curr_blkoff, next_blkoff;
 485	void *kaddr;
 486	int n = 0, ret;
 487
 488	down_read(&NILFS_MDT(cpfile)->mi_sem);
 489
 490	if (curr == 0) {
 491		ret = nilfs_cpfile_get_header_block(cpfile, &bh);
 492		if (ret < 0)
 493			goto out;
 494		kaddr = kmap_atomic(bh->b_page);
 495		header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
 496		curr = le64_to_cpu(header->ch_snapshot_list.ssl_next);
 497		kunmap_atomic(kaddr);
 498		brelse(bh);
 499		if (curr == 0) {
 500			ret = 0;
 501			goto out;
 502		}
 503	} else if (unlikely(curr == ~(__u64)0)) {
 504		ret = 0;
 505		goto out;
 506	}
 507
 508	curr_blkoff = nilfs_cpfile_get_blkoff(cpfile, curr);
 509	ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr, 0, &bh);
 510	if (unlikely(ret < 0)) {
 511		if (ret == -ENOENT)
 512			ret = 0; /* No snapshots (started from a hole block) */
 513		goto out;
 514	}
 515	kaddr = kmap_atomic(bh->b_page);
 516	while (n < nci) {
 517		cp = nilfs_cpfile_block_get_checkpoint(cpfile, curr, bh, kaddr);
 518		curr = ~(__u64)0; /* Terminator */
 519		if (unlikely(nilfs_checkpoint_invalid(cp) ||
 520			     !nilfs_checkpoint_snapshot(cp)))
 521			break;
 522		nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, ci);
 523		ci = (void *)ci + cisz;
 524		n++;
 525		next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
 526		if (next == 0)
 527			break; /* reach end of the snapshot list */
 528
 529		next_blkoff = nilfs_cpfile_get_blkoff(cpfile, next);
 530		if (curr_blkoff != next_blkoff) {
 531			kunmap_atomic(kaddr);
 532			brelse(bh);
 533			ret = nilfs_cpfile_get_checkpoint_block(cpfile, next,
 534								0, &bh);
 535			if (unlikely(ret < 0)) {
 536				WARN_ON(ret == -ENOENT);
 537				goto out;
 538			}
 539			kaddr = kmap_atomic(bh->b_page);
 540		}
 541		curr = next;
 542		curr_blkoff = next_blkoff;
 543	}
 544	kunmap_atomic(kaddr);
 545	brelse(bh);
 546	*cnop = curr;
 547	ret = n;
 548
 549 out:
 550	up_read(&NILFS_MDT(cpfile)->mi_sem);
 551	return ret;
 552}
 553
 554/**
 555 * nilfs_cpfile_get_cpinfo -
 556 * @cpfile:
 557 * @cno:
 558 * @ci:
 559 * @nci:
 560 */
 561
 562ssize_t nilfs_cpfile_get_cpinfo(struct inode *cpfile, __u64 *cnop, int mode,
 563				void *buf, unsigned int cisz, size_t nci)
 564{
 565	switch (mode) {
 566	case NILFS_CHECKPOINT:
 567		return nilfs_cpfile_do_get_cpinfo(cpfile, cnop, buf, cisz, nci);
 568	case NILFS_SNAPSHOT:
 569		return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, buf, cisz, nci);
 570	default:
 571		return -EINVAL;
 572	}
 573}
 574
 575/**
 576 * nilfs_cpfile_delete_checkpoint -
 577 * @cpfile:
 578 * @cno:
 579 */
 580int nilfs_cpfile_delete_checkpoint(struct inode *cpfile, __u64 cno)
 581{
 582	struct nilfs_cpinfo ci;
 583	__u64 tcno = cno;
 584	ssize_t nci;
 585
 586	nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, sizeof(ci), 1);
 587	if (nci < 0)
 588		return nci;
 589	else if (nci == 0 || ci.ci_cno != cno)
 590		return -ENOENT;
 591	else if (nilfs_cpinfo_snapshot(&ci))
 592		return -EBUSY;
 593
 594	return nilfs_cpfile_delete_checkpoints(cpfile, cno, cno + 1);
 595}
 596
 597static struct nilfs_snapshot_list *
 598nilfs_cpfile_block_get_snapshot_list(const struct inode *cpfile,
 599				     __u64 cno,
 600				     struct buffer_head *bh,
 601				     void *kaddr)
 602{
 603	struct nilfs_cpfile_header *header;
 604	struct nilfs_checkpoint *cp;
 605	struct nilfs_snapshot_list *list;
 606
 607	if (cno != 0) {
 608		cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
 609		list = &cp->cp_snapshot_list;
 610	} else {
 611		header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
 612		list = &header->ch_snapshot_list;
 613	}
 614	return list;
 615}
 616
 617static int nilfs_cpfile_set_snapshot(struct inode *cpfile, __u64 cno)
 618{
 619	struct buffer_head *header_bh, *curr_bh, *prev_bh, *cp_bh;
 620	struct nilfs_cpfile_header *header;
 621	struct nilfs_checkpoint *cp;
 622	struct nilfs_snapshot_list *list;
 623	__u64 curr, prev;
 624	unsigned long curr_blkoff, prev_blkoff;
 625	void *kaddr;
 626	int ret;
 627
 628	if (cno == 0)
 629		return -ENOENT; /* checkpoint number 0 is invalid */
 630	down_write(&NILFS_MDT(cpfile)->mi_sem);
 631
 632	ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
 633	if (ret < 0)
 634		goto out_sem;
 635	kaddr = kmap_atomic(cp_bh->b_page);
 636	cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
 637	if (nilfs_checkpoint_invalid(cp)) {
 638		ret = -ENOENT;
 639		kunmap_atomic(kaddr);
 640		goto out_cp;
 641	}
 642	if (nilfs_checkpoint_snapshot(cp)) {
 643		ret = 0;
 644		kunmap_atomic(kaddr);
 645		goto out_cp;
 646	}
 647	kunmap_atomic(kaddr);
 648
 649	ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
 650	if (ret < 0)
 651		goto out_cp;
 652	kaddr = kmap_atomic(header_bh->b_page);
 653	header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
 654	list = &header->ch_snapshot_list;
 655	curr_bh = header_bh;
 656	get_bh(curr_bh);
 657	curr = 0;
 658	curr_blkoff = 0;
 659	prev = le64_to_cpu(list->ssl_prev);
 660	while (prev > cno) {
 661		prev_blkoff = nilfs_cpfile_get_blkoff(cpfile, prev);
 662		curr = prev;
 663		if (curr_blkoff != prev_blkoff) {
 664			kunmap_atomic(kaddr);
 665			brelse(curr_bh);
 666			ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr,
 667								0, &curr_bh);
 668			if (ret < 0)
 669				goto out_header;
 670			kaddr = kmap_atomic(curr_bh->b_page);
 671		}
 672		curr_blkoff = prev_blkoff;
 673		cp = nilfs_cpfile_block_get_checkpoint(
 674			cpfile, curr, curr_bh, kaddr);
 675		list = &cp->cp_snapshot_list;
 676		prev = le64_to_cpu(list->ssl_prev);
 677	}
 678	kunmap_atomic(kaddr);
 679
 680	if (prev != 0) {
 681		ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
 682							&prev_bh);
 683		if (ret < 0)
 684			goto out_curr;
 685	} else {
 686		prev_bh = header_bh;
 687		get_bh(prev_bh);
 688	}
 689
 690	kaddr = kmap_atomic(curr_bh->b_page);
 691	list = nilfs_cpfile_block_get_snapshot_list(
 692		cpfile, curr, curr_bh, kaddr);
 693	list->ssl_prev = cpu_to_le64(cno);
 694	kunmap_atomic(kaddr);
 695
 696	kaddr = kmap_atomic(cp_bh->b_page);
 697	cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
 698	cp->cp_snapshot_list.ssl_next = cpu_to_le64(curr);
 699	cp->cp_snapshot_list.ssl_prev = cpu_to_le64(prev);
 700	nilfs_checkpoint_set_snapshot(cp);
 701	kunmap_atomic(kaddr);
 702
 703	kaddr = kmap_atomic(prev_bh->b_page);
 704	list = nilfs_cpfile_block_get_snapshot_list(
 705		cpfile, prev, prev_bh, kaddr);
 706	list->ssl_next = cpu_to_le64(cno);
 707	kunmap_atomic(kaddr);
 708
 709	kaddr = kmap_atomic(header_bh->b_page);
 710	header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
 711	le64_add_cpu(&header->ch_nsnapshots, 1);
 712	kunmap_atomic(kaddr);
 713
 714	mark_buffer_dirty(prev_bh);
 715	mark_buffer_dirty(curr_bh);
 716	mark_buffer_dirty(cp_bh);
 717	mark_buffer_dirty(header_bh);
 718	nilfs_mdt_mark_dirty(cpfile);
 719
 720	brelse(prev_bh);
 721
 722 out_curr:
 723	brelse(curr_bh);
 724
 725 out_header:
 726	brelse(header_bh);
 727
 728 out_cp:
 729	brelse(cp_bh);
 730
 731 out_sem:
 732	up_write(&NILFS_MDT(cpfile)->mi_sem);
 733	return ret;
 734}
 735
 736static int nilfs_cpfile_clear_snapshot(struct inode *cpfile, __u64 cno)
 737{
 738	struct buffer_head *header_bh, *next_bh, *prev_bh, *cp_bh;
 739	struct nilfs_cpfile_header *header;
 740	struct nilfs_checkpoint *cp;
 741	struct nilfs_snapshot_list *list;
 742	__u64 next, prev;
 743	void *kaddr;
 744	int ret;
 745
 746	if (cno == 0)
 747		return -ENOENT; /* checkpoint number 0 is invalid */
 748	down_write(&NILFS_MDT(cpfile)->mi_sem);
 749
 750	ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
 751	if (ret < 0)
 752		goto out_sem;
 753	kaddr = kmap_atomic(cp_bh->b_page);
 754	cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
 755	if (nilfs_checkpoint_invalid(cp)) {
 756		ret = -ENOENT;
 757		kunmap_atomic(kaddr);
 758		goto out_cp;
 759	}
 760	if (!nilfs_checkpoint_snapshot(cp)) {
 761		ret = 0;
 762		kunmap_atomic(kaddr);
 763		goto out_cp;
 764	}
 765
 766	list = &cp->cp_snapshot_list;
 767	next = le64_to_cpu(list->ssl_next);
 768	prev = le64_to_cpu(list->ssl_prev);
 769	kunmap_atomic(kaddr);
 770
 771	ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
 772	if (ret < 0)
 773		goto out_cp;
 774	if (next != 0) {
 775		ret = nilfs_cpfile_get_checkpoint_block(cpfile, next, 0,
 776							&next_bh);
 777		if (ret < 0)
 778			goto out_header;
 779	} else {
 780		next_bh = header_bh;
 781		get_bh(next_bh);
 782	}
 783	if (prev != 0) {
 784		ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
 785							&prev_bh);
 786		if (ret < 0)
 787			goto out_next;
 788	} else {
 789		prev_bh = header_bh;
 790		get_bh(prev_bh);
 791	}
 792
 793	kaddr = kmap_atomic(next_bh->b_page);
 794	list = nilfs_cpfile_block_get_snapshot_list(
 795		cpfile, next, next_bh, kaddr);
 796	list->ssl_prev = cpu_to_le64(prev);
 797	kunmap_atomic(kaddr);
 798
 799	kaddr = kmap_atomic(prev_bh->b_page);
 800	list = nilfs_cpfile_block_get_snapshot_list(
 801		cpfile, prev, prev_bh, kaddr);
 802	list->ssl_next = cpu_to_le64(next);
 803	kunmap_atomic(kaddr);
 804
 805	kaddr = kmap_atomic(cp_bh->b_page);
 806	cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
 807	cp->cp_snapshot_list.ssl_next = cpu_to_le64(0);
 808	cp->cp_snapshot_list.ssl_prev = cpu_to_le64(0);
 809	nilfs_checkpoint_clear_snapshot(cp);
 810	kunmap_atomic(kaddr);
 811
 812	kaddr = kmap_atomic(header_bh->b_page);
 813	header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
 814	le64_add_cpu(&header->ch_nsnapshots, -1);
 815	kunmap_atomic(kaddr);
 816
 817	mark_buffer_dirty(next_bh);
 818	mark_buffer_dirty(prev_bh);
 819	mark_buffer_dirty(cp_bh);
 820	mark_buffer_dirty(header_bh);
 821	nilfs_mdt_mark_dirty(cpfile);
 822
 823	brelse(prev_bh);
 824
 825 out_next:
 826	brelse(next_bh);
 827
 828 out_header:
 829	brelse(header_bh);
 830
 831 out_cp:
 832	brelse(cp_bh);
 833
 834 out_sem:
 835	up_write(&NILFS_MDT(cpfile)->mi_sem);
 836	return ret;
 837}
 838
 839/**
 840 * nilfs_cpfile_is_snapshot -
 841 * @cpfile: inode of checkpoint file
 842 * @cno: checkpoint number
 843 *
 844 * Description:
 845 *
 846 * Return Value: On success, 1 is returned if the checkpoint specified by
 847 * @cno is a snapshot, or 0 if not. On error, one of the following negative
 848 * error codes is returned.
 849 *
 850 * %-EIO - I/O error.
 851 *
 852 * %-ENOMEM - Insufficient amount of memory available.
 853 *
 854 * %-ENOENT - No such checkpoint.
 855 */
 856int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
 857{
 858	struct buffer_head *bh;
 859	struct nilfs_checkpoint *cp;
 860	void *kaddr;
 861	int ret;
 862
 863	/*
 864	 * CP number is invalid if it's zero or larger than the
 865	 * largest existing one.
 866	 */
 867	if (cno == 0 || cno >= nilfs_mdt_cno(cpfile))
 868		return -ENOENT;
 869	down_read(&NILFS_MDT(cpfile)->mi_sem);
 870
 871	ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
 872	if (ret < 0)
 873		goto out;
 874	kaddr = kmap_atomic(bh->b_page);
 875	cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
 876	if (nilfs_checkpoint_invalid(cp))
 877		ret = -ENOENT;
 878	else
 879		ret = nilfs_checkpoint_snapshot(cp);
 880	kunmap_atomic(kaddr);
 881	brelse(bh);
 882
 883 out:
 884	up_read(&NILFS_MDT(cpfile)->mi_sem);
 885	return ret;
 886}
 887
 888/**
 889 * nilfs_cpfile_change_cpmode - change checkpoint mode
 890 * @cpfile: inode of checkpoint file
 891 * @cno: checkpoint number
 892 * @mode: mode of checkpoint
 893 *
 894 * Description: nilfs_change_cpmode() changes the mode of the checkpoint
 895 * specified by @cno. The mode @mode is NILFS_CHECKPOINT or NILFS_SNAPSHOT.
 896 *
 897 * Return Value: On success, 0 is returned. On error, one of the following
 898 * negative error codes is returned.
 899 *
 900 * %-EIO - I/O error.
 901 *
 902 * %-ENOMEM - Insufficient amount of memory available.
 903 *
 904 * %-ENOENT - No such checkpoint.
 905 */
 906int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode)
 907{
 908	int ret;
 909
 910	switch (mode) {
 911	case NILFS_CHECKPOINT:
 912		if (nilfs_checkpoint_is_mounted(cpfile->i_sb, cno))
 913			/*
 914			 * Current implementation does not have to protect
 915			 * plain read-only mounts since they are exclusive
 916			 * with a read/write mount and are protected from the
 917			 * cleaner.
 918			 */
 919			ret = -EBUSY;
 920		else
 921			ret = nilfs_cpfile_clear_snapshot(cpfile, cno);
 922		return ret;
 923	case NILFS_SNAPSHOT:
 924		return nilfs_cpfile_set_snapshot(cpfile, cno);
 925	default:
 926		return -EINVAL;
 927	}
 928}
 929
 930/**
 931 * nilfs_cpfile_get_stat - get checkpoint statistics
 932 * @cpfile: inode of checkpoint file
 933 * @cpstat: pointer to a structure of checkpoint statistics
 934 *
 935 * Description: nilfs_cpfile_get_stat() returns information about checkpoints.
 936 *
 937 * Return Value: On success, 0 is returned, and checkpoints information is
 938 * stored in the place pointed by @cpstat. On error, one of the following
 939 * negative error codes is returned.
 940 *
 941 * %-EIO - I/O error.
 942 *
 943 * %-ENOMEM - Insufficient amount of memory available.
 944 */
 945int nilfs_cpfile_get_stat(struct inode *cpfile, struct nilfs_cpstat *cpstat)
 946{
 947	struct buffer_head *bh;
 948	struct nilfs_cpfile_header *header;
 949	void *kaddr;
 950	int ret;
 951
 952	down_read(&NILFS_MDT(cpfile)->mi_sem);
 953
 954	ret = nilfs_cpfile_get_header_block(cpfile, &bh);
 955	if (ret < 0)
 956		goto out_sem;
 957	kaddr = kmap_atomic(bh->b_page);
 958	header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
 959	cpstat->cs_cno = nilfs_mdt_cno(cpfile);
 960	cpstat->cs_ncps = le64_to_cpu(header->ch_ncheckpoints);
 961	cpstat->cs_nsss = le64_to_cpu(header->ch_nsnapshots);
 962	kunmap_atomic(kaddr);
 963	brelse(bh);
 964
 965 out_sem:
 966	up_read(&NILFS_MDT(cpfile)->mi_sem);
 967	return ret;
 968}
 969
 970/**
 971 * nilfs_cpfile_read - read or get cpfile inode
 972 * @sb: super block instance
 973 * @cpsize: size of a checkpoint entry
 974 * @raw_inode: on-disk cpfile inode
 975 * @inodep: buffer to store the inode
 976 */
 977int nilfs_cpfile_read(struct super_block *sb, size_t cpsize,
 978		      struct nilfs_inode *raw_inode, struct inode **inodep)
 979{
 980	struct inode *cpfile;
 981	int err;
 982
 983	if (cpsize > sb->s_blocksize) {
 984		nilfs_err(sb, "too large checkpoint size: %zu bytes", cpsize);
 985		return -EINVAL;
 986	} else if (cpsize < NILFS_MIN_CHECKPOINT_SIZE) {
 987		nilfs_err(sb, "too small checkpoint size: %zu bytes", cpsize);
 988		return -EINVAL;
 989	}
 990
 991	cpfile = nilfs_iget_locked(sb, NULL, NILFS_CPFILE_INO);
 992	if (unlikely(!cpfile))
 993		return -ENOMEM;
 994	if (!(cpfile->i_state & I_NEW))
 995		goto out;
 996
 997	err = nilfs_mdt_init(cpfile, NILFS_MDT_GFP, 0);
 998	if (err)
 999		goto failed;
1000
1001	nilfs_mdt_set_entry_size(cpfile, cpsize,
1002				 sizeof(struct nilfs_cpfile_header));
1003
1004	err = nilfs_read_inode_common(cpfile, raw_inode);
1005	if (err)
1006		goto failed;
1007
1008	unlock_new_inode(cpfile);
1009 out:
1010	*inodep = cpfile;
1011	return 0;
1012 failed:
1013	iget_failed(cpfile);
1014	return err;
1015}
v3.1
 
  1/*
  2 * cpfile.c - NILFS checkpoint file.
  3 *
  4 * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
  5 *
  6 * This program is free software; you can redistribute it and/or modify
  7 * it under the terms of the GNU General Public License as published by
  8 * the Free Software Foundation; either version 2 of the License, or
  9 * (at your option) any later version.
 10 *
 11 * This program is distributed in the hope that it will be useful,
 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 14 * GNU General Public License for more details.
 15 *
 16 * You should have received a copy of the GNU General Public License
 17 * along with this program; if not, write to the Free Software
 18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 19 *
 20 * Written by Koji Sato <koji@osrg.net>.
 21 */
 22
 23#include <linux/kernel.h>
 24#include <linux/fs.h>
 25#include <linux/string.h>
 26#include <linux/buffer_head.h>
 27#include <linux/errno.h>
 28#include <linux/nilfs2_fs.h>
 29#include "mdt.h"
 30#include "cpfile.h"
 31
 32
 33static inline unsigned long
 34nilfs_cpfile_checkpoints_per_block(const struct inode *cpfile)
 35{
 36	return NILFS_MDT(cpfile)->mi_entries_per_block;
 37}
 38
 39/* block number from the beginning of the file */
 40static unsigned long
 41nilfs_cpfile_get_blkoff(const struct inode *cpfile, __u64 cno)
 42{
 43	__u64 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
 
 44	do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile));
 45	return (unsigned long)tcno;
 46}
 47
 48/* offset in block */
 49static unsigned long
 50nilfs_cpfile_get_offset(const struct inode *cpfile, __u64 cno)
 51{
 52	__u64 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
 
 53	return do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile));
 54}
 55
 
 
 
 
 
 
 
 56static unsigned long
 57nilfs_cpfile_checkpoints_in_block(const struct inode *cpfile,
 58				  __u64 curr,
 59				  __u64 max)
 60{
 61	return min_t(__u64,
 62		     nilfs_cpfile_checkpoints_per_block(cpfile) -
 63		     nilfs_cpfile_get_offset(cpfile, curr),
 64		     max - curr);
 65}
 66
 67static inline int nilfs_cpfile_is_in_first(const struct inode *cpfile,
 68					   __u64 cno)
 69{
 70	return nilfs_cpfile_get_blkoff(cpfile, cno) == 0;
 71}
 72
 73static unsigned int
 74nilfs_cpfile_block_add_valid_checkpoints(const struct inode *cpfile,
 75					 struct buffer_head *bh,
 76					 void *kaddr,
 77					 unsigned int n)
 78{
 79	struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
 80	unsigned int count;
 81
 82	count = le32_to_cpu(cp->cp_checkpoints_count) + n;
 83	cp->cp_checkpoints_count = cpu_to_le32(count);
 84	return count;
 85}
 86
 87static unsigned int
 88nilfs_cpfile_block_sub_valid_checkpoints(const struct inode *cpfile,
 89					 struct buffer_head *bh,
 90					 void *kaddr,
 91					 unsigned int n)
 92{
 93	struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
 94	unsigned int count;
 95
 96	WARN_ON(le32_to_cpu(cp->cp_checkpoints_count) < n);
 97	count = le32_to_cpu(cp->cp_checkpoints_count) - n;
 98	cp->cp_checkpoints_count = cpu_to_le32(count);
 99	return count;
100}
101
102static inline struct nilfs_cpfile_header *
103nilfs_cpfile_block_get_header(const struct inode *cpfile,
104			      struct buffer_head *bh,
105			      void *kaddr)
106{
107	return kaddr + bh_offset(bh);
108}
109
110static struct nilfs_checkpoint *
111nilfs_cpfile_block_get_checkpoint(const struct inode *cpfile, __u64 cno,
112				  struct buffer_head *bh,
113				  void *kaddr)
114{
115	return kaddr + bh_offset(bh) + nilfs_cpfile_get_offset(cpfile, cno) *
116		NILFS_MDT(cpfile)->mi_entry_size;
117}
118
119static void nilfs_cpfile_block_init(struct inode *cpfile,
120				    struct buffer_head *bh,
121				    void *kaddr)
122{
123	struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
124	size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
125	int n = nilfs_cpfile_checkpoints_per_block(cpfile);
126
127	while (n-- > 0) {
128		nilfs_checkpoint_set_invalid(cp);
129		cp = (void *)cp + cpsz;
130	}
131}
132
133static inline int nilfs_cpfile_get_header_block(struct inode *cpfile,
134						struct buffer_head **bhp)
135{
136	return nilfs_mdt_get_block(cpfile, 0, 0, NULL, bhp);
137}
138
139static inline int nilfs_cpfile_get_checkpoint_block(struct inode *cpfile,
140						    __u64 cno,
141						    int create,
142						    struct buffer_head **bhp)
143{
144	return nilfs_mdt_get_block(cpfile,
145				   nilfs_cpfile_get_blkoff(cpfile, cno),
146				   create, nilfs_cpfile_block_init, bhp);
147}
148
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
149static inline int nilfs_cpfile_delete_checkpoint_block(struct inode *cpfile,
150						       __u64 cno)
151{
152	return nilfs_mdt_delete_block(cpfile,
153				      nilfs_cpfile_get_blkoff(cpfile, cno));
154}
155
156/**
157 * nilfs_cpfile_get_checkpoint - get a checkpoint
158 * @cpfile: inode of checkpoint file
159 * @cno: checkpoint number
160 * @create: create flag
161 * @cpp: pointer to a checkpoint
162 * @bhp: pointer to a buffer head
163 *
164 * Description: nilfs_cpfile_get_checkpoint() acquires the checkpoint
165 * specified by @cno. A new checkpoint will be created if @cno is the current
166 * checkpoint number and @create is nonzero.
167 *
168 * Return Value: On success, 0 is returned, and the checkpoint and the
169 * buffer head of the buffer on which the checkpoint is located are stored in
170 * the place pointed by @cpp and @bhp, respectively. On error, one of the
171 * following negative error codes is returned.
172 *
173 * %-EIO - I/O error.
174 *
175 * %-ENOMEM - Insufficient amount of memory available.
176 *
177 * %-ENOENT - No such checkpoint.
178 *
179 * %-EINVAL - invalid checkpoint.
180 */
181int nilfs_cpfile_get_checkpoint(struct inode *cpfile,
182				__u64 cno,
183				int create,
184				struct nilfs_checkpoint **cpp,
185				struct buffer_head **bhp)
186{
187	struct buffer_head *header_bh, *cp_bh;
188	struct nilfs_cpfile_header *header;
189	struct nilfs_checkpoint *cp;
190	void *kaddr;
191	int ret;
192
193	if (unlikely(cno < 1 || cno > nilfs_mdt_cno(cpfile) ||
194		     (cno < nilfs_mdt_cno(cpfile) && create)))
195		return -EINVAL;
196
197	down_write(&NILFS_MDT(cpfile)->mi_sem);
198
199	ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
200	if (ret < 0)
201		goto out_sem;
202	ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, create, &cp_bh);
203	if (ret < 0)
204		goto out_header;
205	kaddr = kmap(cp_bh->b_page);
206	cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
207	if (nilfs_checkpoint_invalid(cp)) {
208		if (!create) {
209			kunmap(cp_bh->b_page);
210			brelse(cp_bh);
211			ret = -ENOENT;
212			goto out_header;
213		}
214		/* a newly-created checkpoint */
215		nilfs_checkpoint_clear_invalid(cp);
216		if (!nilfs_cpfile_is_in_first(cpfile, cno))
217			nilfs_cpfile_block_add_valid_checkpoints(cpfile, cp_bh,
218								 kaddr, 1);
219		mark_buffer_dirty(cp_bh);
220
221		kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
222		header = nilfs_cpfile_block_get_header(cpfile, header_bh,
223						       kaddr);
224		le64_add_cpu(&header->ch_ncheckpoints, 1);
225		kunmap_atomic(kaddr, KM_USER0);
226		mark_buffer_dirty(header_bh);
227		nilfs_mdt_mark_dirty(cpfile);
228	}
229
230	if (cpp != NULL)
231		*cpp = cp;
232	*bhp = cp_bh;
233
234 out_header:
235	brelse(header_bh);
236
237 out_sem:
238	up_write(&NILFS_MDT(cpfile)->mi_sem);
239	return ret;
240}
241
242/**
243 * nilfs_cpfile_put_checkpoint - put a checkpoint
244 * @cpfile: inode of checkpoint file
245 * @cno: checkpoint number
246 * @bh: buffer head
247 *
248 * Description: nilfs_cpfile_put_checkpoint() releases the checkpoint
249 * specified by @cno. @bh must be the buffer head which has been returned by
250 * a previous call to nilfs_cpfile_get_checkpoint() with @cno.
251 */
252void nilfs_cpfile_put_checkpoint(struct inode *cpfile, __u64 cno,
253				 struct buffer_head *bh)
254{
255	kunmap(bh->b_page);
256	brelse(bh);
257}
258
259/**
260 * nilfs_cpfile_delete_checkpoints - delete checkpoints
261 * @cpfile: inode of checkpoint file
262 * @start: start checkpoint number
263 * @end: end checkpoint numer
264 *
265 * Description: nilfs_cpfile_delete_checkpoints() deletes the checkpoints in
266 * the period from @start to @end, excluding @end itself. The checkpoints
267 * which have been already deleted are ignored.
268 *
269 * Return Value: On success, 0 is returned. On error, one of the following
270 * negative error codes is returned.
271 *
272 * %-EIO - I/O error.
273 *
274 * %-ENOMEM - Insufficient amount of memory available.
275 *
276 * %-EINVAL - invalid checkpoints.
277 */
278int nilfs_cpfile_delete_checkpoints(struct inode *cpfile,
279				    __u64 start,
280				    __u64 end)
281{
282	struct buffer_head *header_bh, *cp_bh;
283	struct nilfs_cpfile_header *header;
284	struct nilfs_checkpoint *cp;
285	size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
286	__u64 cno;
287	void *kaddr;
288	unsigned long tnicps;
289	int ret, ncps, nicps, count, i;
290
291	if (unlikely(start == 0 || start > end)) {
292		printk(KERN_ERR "%s: invalid range of checkpoint numbers: "
293		       "[%llu, %llu)\n", __func__,
294		       (unsigned long long)start, (unsigned long long)end);
295		return -EINVAL;
296	}
297
298	down_write(&NILFS_MDT(cpfile)->mi_sem);
299
300	ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
301	if (ret < 0)
302		goto out_sem;
303	tnicps = 0;
 
304
305	for (cno = start; cno < end; cno += ncps) {
306		ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, end);
307		ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
308		if (ret < 0) {
309			if (ret != -ENOENT)
310				break;
311			/* skip hole */
312			ret = 0;
313			continue;
314		}
315
316		kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
317		cp = nilfs_cpfile_block_get_checkpoint(
318			cpfile, cno, cp_bh, kaddr);
319		nicps = 0;
320		for (i = 0; i < ncps; i++, cp = (void *)cp + cpsz) {
321			WARN_ON(nilfs_checkpoint_snapshot(cp));
322			if (!nilfs_checkpoint_invalid(cp)) {
 
323				nilfs_checkpoint_set_invalid(cp);
324				nicps++;
325			}
326		}
327		if (nicps > 0) {
328			tnicps += nicps;
329			mark_buffer_dirty(cp_bh);
330			nilfs_mdt_mark_dirty(cpfile);
331			if (!nilfs_cpfile_is_in_first(cpfile, cno)) {
332				count =
333				  nilfs_cpfile_block_sub_valid_checkpoints(
334						cpfile, cp_bh, kaddr, nicps);
335				if (count == 0) {
336					/* make hole */
337					kunmap_atomic(kaddr, KM_USER0);
338					brelse(cp_bh);
339					ret =
340					  nilfs_cpfile_delete_checkpoint_block(
341								   cpfile, cno);
342					if (ret == 0)
343						continue;
344					printk(KERN_ERR
345					       "%s: cannot delete block\n",
346					       __func__);
347					break;
348				}
349			}
350		}
351
352		kunmap_atomic(kaddr, KM_USER0);
353		brelse(cp_bh);
354	}
355
356	if (tnicps > 0) {
357		kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
358		header = nilfs_cpfile_block_get_header(cpfile, header_bh,
359						       kaddr);
360		le64_add_cpu(&header->ch_ncheckpoints, -(u64)tnicps);
361		mark_buffer_dirty(header_bh);
362		nilfs_mdt_mark_dirty(cpfile);
363		kunmap_atomic(kaddr, KM_USER0);
364	}
365
366	brelse(header_bh);
 
 
367
368 out_sem:
369	up_write(&NILFS_MDT(cpfile)->mi_sem);
370	return ret;
371}
372
373static void nilfs_cpfile_checkpoint_to_cpinfo(struct inode *cpfile,
374					      struct nilfs_checkpoint *cp,
375					      struct nilfs_cpinfo *ci)
376{
377	ci->ci_flags = le32_to_cpu(cp->cp_flags);
378	ci->ci_cno = le64_to_cpu(cp->cp_cno);
379	ci->ci_create = le64_to_cpu(cp->cp_create);
380	ci->ci_nblk_inc = le64_to_cpu(cp->cp_nblk_inc);
381	ci->ci_inodes_count = le64_to_cpu(cp->cp_inodes_count);
382	ci->ci_blocks_count = le64_to_cpu(cp->cp_blocks_count);
383	ci->ci_next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
384}
385
386static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop,
387					  void *buf, unsigned cisz, size_t nci)
 
388{
389	struct nilfs_checkpoint *cp;
390	struct nilfs_cpinfo *ci = buf;
391	struct buffer_head *bh;
392	size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
393	__u64 cur_cno = nilfs_mdt_cno(cpfile), cno = *cnop;
394	void *kaddr;
395	int n, ret;
396	int ncps, i;
397
398	if (cno == 0)
399		return -ENOENT; /* checkpoint number 0 is invalid */
400	down_read(&NILFS_MDT(cpfile)->mi_sem);
401
402	for (n = 0; cno < cur_cno && n < nci; cno += ncps) {
403		ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, cur_cno);
404		ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
405		if (ret < 0) {
406			if (ret != -ENOENT)
407				goto out;
408			continue; /* skip hole */
409		}
 
410
411		kaddr = kmap_atomic(bh->b_page, KM_USER0);
412		cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
413		for (i = 0; i < ncps && n < nci; i++, cp = (void *)cp + cpsz) {
414			if (!nilfs_checkpoint_invalid(cp)) {
415				nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp,
416								  ci);
417				ci = (void *)ci + cisz;
418				n++;
419			}
420		}
421		kunmap_atomic(kaddr, KM_USER0);
422		brelse(bh);
423	}
424
425	ret = n;
426	if (n > 0) {
427		ci = (void *)ci - cisz;
428		*cnop = ci->ci_cno + 1;
429	}
430
431 out:
432	up_read(&NILFS_MDT(cpfile)->mi_sem);
433	return ret;
434}
435
436static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
437					  void *buf, unsigned cisz, size_t nci)
 
438{
439	struct buffer_head *bh;
440	struct nilfs_cpfile_header *header;
441	struct nilfs_checkpoint *cp;
442	struct nilfs_cpinfo *ci = buf;
443	__u64 curr = *cnop, next;
444	unsigned long curr_blkoff, next_blkoff;
445	void *kaddr;
446	int n = 0, ret;
447
448	down_read(&NILFS_MDT(cpfile)->mi_sem);
449
450	if (curr == 0) {
451		ret = nilfs_cpfile_get_header_block(cpfile, &bh);
452		if (ret < 0)
453			goto out;
454		kaddr = kmap_atomic(bh->b_page, KM_USER0);
455		header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
456		curr = le64_to_cpu(header->ch_snapshot_list.ssl_next);
457		kunmap_atomic(kaddr, KM_USER0);
458		brelse(bh);
459		if (curr == 0) {
460			ret = 0;
461			goto out;
462		}
463	} else if (unlikely(curr == ~(__u64)0)) {
464		ret = 0;
465		goto out;
466	}
467
468	curr_blkoff = nilfs_cpfile_get_blkoff(cpfile, curr);
469	ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr, 0, &bh);
470	if (unlikely(ret < 0)) {
471		if (ret == -ENOENT)
472			ret = 0; /* No snapshots (started from a hole block) */
473		goto out;
474	}
475	kaddr = kmap_atomic(bh->b_page, KM_USER0);
476	while (n < nci) {
477		cp = nilfs_cpfile_block_get_checkpoint(cpfile, curr, bh, kaddr);
478		curr = ~(__u64)0; /* Terminator */
479		if (unlikely(nilfs_checkpoint_invalid(cp) ||
480			     !nilfs_checkpoint_snapshot(cp)))
481			break;
482		nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, ci);
483		ci = (void *)ci + cisz;
484		n++;
485		next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
486		if (next == 0)
487			break; /* reach end of the snapshot list */
488
489		next_blkoff = nilfs_cpfile_get_blkoff(cpfile, next);
490		if (curr_blkoff != next_blkoff) {
491			kunmap_atomic(kaddr, KM_USER0);
492			brelse(bh);
493			ret = nilfs_cpfile_get_checkpoint_block(cpfile, next,
494								0, &bh);
495			if (unlikely(ret < 0)) {
496				WARN_ON(ret == -ENOENT);
497				goto out;
498			}
499			kaddr = kmap_atomic(bh->b_page, KM_USER0);
500		}
501		curr = next;
502		curr_blkoff = next_blkoff;
503	}
504	kunmap_atomic(kaddr, KM_USER0);
505	brelse(bh);
506	*cnop = curr;
507	ret = n;
508
509 out:
510	up_read(&NILFS_MDT(cpfile)->mi_sem);
511	return ret;
512}
513
514/**
515 * nilfs_cpfile_get_cpinfo -
516 * @cpfile:
517 * @cno:
518 * @ci:
519 * @nci:
520 */
521
522ssize_t nilfs_cpfile_get_cpinfo(struct inode *cpfile, __u64 *cnop, int mode,
523				void *buf, unsigned cisz, size_t nci)
524{
525	switch (mode) {
526	case NILFS_CHECKPOINT:
527		return nilfs_cpfile_do_get_cpinfo(cpfile, cnop, buf, cisz, nci);
528	case NILFS_SNAPSHOT:
529		return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, buf, cisz, nci);
530	default:
531		return -EINVAL;
532	}
533}
534
535/**
536 * nilfs_cpfile_delete_checkpoint -
537 * @cpfile:
538 * @cno:
539 */
540int nilfs_cpfile_delete_checkpoint(struct inode *cpfile, __u64 cno)
541{
542	struct nilfs_cpinfo ci;
543	__u64 tcno = cno;
544	ssize_t nci;
545
546	nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, sizeof(ci), 1);
547	if (nci < 0)
548		return nci;
549	else if (nci == 0 || ci.ci_cno != cno)
550		return -ENOENT;
551	else if (nilfs_cpinfo_snapshot(&ci))
552		return -EBUSY;
553
554	return nilfs_cpfile_delete_checkpoints(cpfile, cno, cno + 1);
555}
556
557static struct nilfs_snapshot_list *
558nilfs_cpfile_block_get_snapshot_list(const struct inode *cpfile,
559				     __u64 cno,
560				     struct buffer_head *bh,
561				     void *kaddr)
562{
563	struct nilfs_cpfile_header *header;
564	struct nilfs_checkpoint *cp;
565	struct nilfs_snapshot_list *list;
566
567	if (cno != 0) {
568		cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
569		list = &cp->cp_snapshot_list;
570	} else {
571		header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
572		list = &header->ch_snapshot_list;
573	}
574	return list;
575}
576
577static int nilfs_cpfile_set_snapshot(struct inode *cpfile, __u64 cno)
578{
579	struct buffer_head *header_bh, *curr_bh, *prev_bh, *cp_bh;
580	struct nilfs_cpfile_header *header;
581	struct nilfs_checkpoint *cp;
582	struct nilfs_snapshot_list *list;
583	__u64 curr, prev;
584	unsigned long curr_blkoff, prev_blkoff;
585	void *kaddr;
586	int ret;
587
588	if (cno == 0)
589		return -ENOENT; /* checkpoint number 0 is invalid */
590	down_write(&NILFS_MDT(cpfile)->mi_sem);
591
592	ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
593	if (ret < 0)
594		goto out_sem;
595	kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
596	cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
597	if (nilfs_checkpoint_invalid(cp)) {
598		ret = -ENOENT;
599		kunmap_atomic(kaddr, KM_USER0);
600		goto out_cp;
601	}
602	if (nilfs_checkpoint_snapshot(cp)) {
603		ret = 0;
604		kunmap_atomic(kaddr, KM_USER0);
605		goto out_cp;
606	}
607	kunmap_atomic(kaddr, KM_USER0);
608
609	ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
610	if (ret < 0)
611		goto out_cp;
612	kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
613	header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
614	list = &header->ch_snapshot_list;
615	curr_bh = header_bh;
616	get_bh(curr_bh);
617	curr = 0;
618	curr_blkoff = 0;
619	prev = le64_to_cpu(list->ssl_prev);
620	while (prev > cno) {
621		prev_blkoff = nilfs_cpfile_get_blkoff(cpfile, prev);
622		curr = prev;
623		if (curr_blkoff != prev_blkoff) {
624			kunmap_atomic(kaddr, KM_USER0);
625			brelse(curr_bh);
626			ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr,
627								0, &curr_bh);
628			if (ret < 0)
629				goto out_header;
630			kaddr = kmap_atomic(curr_bh->b_page, KM_USER0);
631		}
632		curr_blkoff = prev_blkoff;
633		cp = nilfs_cpfile_block_get_checkpoint(
634			cpfile, curr, curr_bh, kaddr);
635		list = &cp->cp_snapshot_list;
636		prev = le64_to_cpu(list->ssl_prev);
637	}
638	kunmap_atomic(kaddr, KM_USER0);
639
640	if (prev != 0) {
641		ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
642							&prev_bh);
643		if (ret < 0)
644			goto out_curr;
645	} else {
646		prev_bh = header_bh;
647		get_bh(prev_bh);
648	}
649
650	kaddr = kmap_atomic(curr_bh->b_page, KM_USER0);
651	list = nilfs_cpfile_block_get_snapshot_list(
652		cpfile, curr, curr_bh, kaddr);
653	list->ssl_prev = cpu_to_le64(cno);
654	kunmap_atomic(kaddr, KM_USER0);
655
656	kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
657	cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
658	cp->cp_snapshot_list.ssl_next = cpu_to_le64(curr);
659	cp->cp_snapshot_list.ssl_prev = cpu_to_le64(prev);
660	nilfs_checkpoint_set_snapshot(cp);
661	kunmap_atomic(kaddr, KM_USER0);
662
663	kaddr = kmap_atomic(prev_bh->b_page, KM_USER0);
664	list = nilfs_cpfile_block_get_snapshot_list(
665		cpfile, prev, prev_bh, kaddr);
666	list->ssl_next = cpu_to_le64(cno);
667	kunmap_atomic(kaddr, KM_USER0);
668
669	kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
670	header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
671	le64_add_cpu(&header->ch_nsnapshots, 1);
672	kunmap_atomic(kaddr, KM_USER0);
673
674	mark_buffer_dirty(prev_bh);
675	mark_buffer_dirty(curr_bh);
676	mark_buffer_dirty(cp_bh);
677	mark_buffer_dirty(header_bh);
678	nilfs_mdt_mark_dirty(cpfile);
679
680	brelse(prev_bh);
681
682 out_curr:
683	brelse(curr_bh);
684
685 out_header:
686	brelse(header_bh);
687
688 out_cp:
689	brelse(cp_bh);
690
691 out_sem:
692	up_write(&NILFS_MDT(cpfile)->mi_sem);
693	return ret;
694}
695
696static int nilfs_cpfile_clear_snapshot(struct inode *cpfile, __u64 cno)
697{
698	struct buffer_head *header_bh, *next_bh, *prev_bh, *cp_bh;
699	struct nilfs_cpfile_header *header;
700	struct nilfs_checkpoint *cp;
701	struct nilfs_snapshot_list *list;
702	__u64 next, prev;
703	void *kaddr;
704	int ret;
705
706	if (cno == 0)
707		return -ENOENT; /* checkpoint number 0 is invalid */
708	down_write(&NILFS_MDT(cpfile)->mi_sem);
709
710	ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
711	if (ret < 0)
712		goto out_sem;
713	kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
714	cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
715	if (nilfs_checkpoint_invalid(cp)) {
716		ret = -ENOENT;
717		kunmap_atomic(kaddr, KM_USER0);
718		goto out_cp;
719	}
720	if (!nilfs_checkpoint_snapshot(cp)) {
721		ret = 0;
722		kunmap_atomic(kaddr, KM_USER0);
723		goto out_cp;
724	}
725
726	list = &cp->cp_snapshot_list;
727	next = le64_to_cpu(list->ssl_next);
728	prev = le64_to_cpu(list->ssl_prev);
729	kunmap_atomic(kaddr, KM_USER0);
730
731	ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
732	if (ret < 0)
733		goto out_cp;
734	if (next != 0) {
735		ret = nilfs_cpfile_get_checkpoint_block(cpfile, next, 0,
736							&next_bh);
737		if (ret < 0)
738			goto out_header;
739	} else {
740		next_bh = header_bh;
741		get_bh(next_bh);
742	}
743	if (prev != 0) {
744		ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
745							&prev_bh);
746		if (ret < 0)
747			goto out_next;
748	} else {
749		prev_bh = header_bh;
750		get_bh(prev_bh);
751	}
752
753	kaddr = kmap_atomic(next_bh->b_page, KM_USER0);
754	list = nilfs_cpfile_block_get_snapshot_list(
755		cpfile, next, next_bh, kaddr);
756	list->ssl_prev = cpu_to_le64(prev);
757	kunmap_atomic(kaddr, KM_USER0);
758
759	kaddr = kmap_atomic(prev_bh->b_page, KM_USER0);
760	list = nilfs_cpfile_block_get_snapshot_list(
761		cpfile, prev, prev_bh, kaddr);
762	list->ssl_next = cpu_to_le64(next);
763	kunmap_atomic(kaddr, KM_USER0);
764
765	kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
766	cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
767	cp->cp_snapshot_list.ssl_next = cpu_to_le64(0);
768	cp->cp_snapshot_list.ssl_prev = cpu_to_le64(0);
769	nilfs_checkpoint_clear_snapshot(cp);
770	kunmap_atomic(kaddr, KM_USER0);
771
772	kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
773	header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
774	le64_add_cpu(&header->ch_nsnapshots, -1);
775	kunmap_atomic(kaddr, KM_USER0);
776
777	mark_buffer_dirty(next_bh);
778	mark_buffer_dirty(prev_bh);
779	mark_buffer_dirty(cp_bh);
780	mark_buffer_dirty(header_bh);
781	nilfs_mdt_mark_dirty(cpfile);
782
783	brelse(prev_bh);
784
785 out_next:
786	brelse(next_bh);
787
788 out_header:
789	brelse(header_bh);
790
791 out_cp:
792	brelse(cp_bh);
793
794 out_sem:
795	up_write(&NILFS_MDT(cpfile)->mi_sem);
796	return ret;
797}
798
799/**
800 * nilfs_cpfile_is_snapshot -
801 * @cpfile: inode of checkpoint file
802 * @cno: checkpoint number
803 *
804 * Description:
805 *
806 * Return Value: On success, 1 is returned if the checkpoint specified by
807 * @cno is a snapshot, or 0 if not. On error, one of the following negative
808 * error codes is returned.
809 *
810 * %-EIO - I/O error.
811 *
812 * %-ENOMEM - Insufficient amount of memory available.
813 *
814 * %-ENOENT - No such checkpoint.
815 */
816int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
817{
818	struct buffer_head *bh;
819	struct nilfs_checkpoint *cp;
820	void *kaddr;
821	int ret;
822
823	/* CP number is invalid if it's zero or larger than the
824	largest	exist one.*/
 
 
825	if (cno == 0 || cno >= nilfs_mdt_cno(cpfile))
826		return -ENOENT;
827	down_read(&NILFS_MDT(cpfile)->mi_sem);
828
829	ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
830	if (ret < 0)
831		goto out;
832	kaddr = kmap_atomic(bh->b_page, KM_USER0);
833	cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
834	if (nilfs_checkpoint_invalid(cp))
835		ret = -ENOENT;
836	else
837		ret = nilfs_checkpoint_snapshot(cp);
838	kunmap_atomic(kaddr, KM_USER0);
839	brelse(bh);
840
841 out:
842	up_read(&NILFS_MDT(cpfile)->mi_sem);
843	return ret;
844}
845
846/**
847 * nilfs_cpfile_change_cpmode - change checkpoint mode
848 * @cpfile: inode of checkpoint file
849 * @cno: checkpoint number
850 * @status: mode of checkpoint
851 *
852 * Description: nilfs_change_cpmode() changes the mode of the checkpoint
853 * specified by @cno. The mode @mode is NILFS_CHECKPOINT or NILFS_SNAPSHOT.
854 *
855 * Return Value: On success, 0 is returned. On error, one of the following
856 * negative error codes is returned.
857 *
858 * %-EIO - I/O error.
859 *
860 * %-ENOMEM - Insufficient amount of memory available.
861 *
862 * %-ENOENT - No such checkpoint.
863 */
864int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode)
865{
866	int ret;
867
868	switch (mode) {
869	case NILFS_CHECKPOINT:
870		if (nilfs_checkpoint_is_mounted(cpfile->i_sb, cno))
871			/*
872			 * Current implementation does not have to protect
873			 * plain read-only mounts since they are exclusive
874			 * with a read/write mount and are protected from the
875			 * cleaner.
876			 */
877			ret = -EBUSY;
878		else
879			ret = nilfs_cpfile_clear_snapshot(cpfile, cno);
880		return ret;
881	case NILFS_SNAPSHOT:
882		return nilfs_cpfile_set_snapshot(cpfile, cno);
883	default:
884		return -EINVAL;
885	}
886}
887
888/**
889 * nilfs_cpfile_get_stat - get checkpoint statistics
890 * @cpfile: inode of checkpoint file
891 * @stat: pointer to a structure of checkpoint statistics
892 *
893 * Description: nilfs_cpfile_get_stat() returns information about checkpoints.
894 *
895 * Return Value: On success, 0 is returned, and checkpoints information is
896 * stored in the place pointed by @stat. On error, one of the following
897 * negative error codes is returned.
898 *
899 * %-EIO - I/O error.
900 *
901 * %-ENOMEM - Insufficient amount of memory available.
902 */
903int nilfs_cpfile_get_stat(struct inode *cpfile, struct nilfs_cpstat *cpstat)
904{
905	struct buffer_head *bh;
906	struct nilfs_cpfile_header *header;
907	void *kaddr;
908	int ret;
909
910	down_read(&NILFS_MDT(cpfile)->mi_sem);
911
912	ret = nilfs_cpfile_get_header_block(cpfile, &bh);
913	if (ret < 0)
914		goto out_sem;
915	kaddr = kmap_atomic(bh->b_page, KM_USER0);
916	header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
917	cpstat->cs_cno = nilfs_mdt_cno(cpfile);
918	cpstat->cs_ncps = le64_to_cpu(header->ch_ncheckpoints);
919	cpstat->cs_nsss = le64_to_cpu(header->ch_nsnapshots);
920	kunmap_atomic(kaddr, KM_USER0);
921	brelse(bh);
922
923 out_sem:
924	up_read(&NILFS_MDT(cpfile)->mi_sem);
925	return ret;
926}
927
928/**
929 * nilfs_cpfile_read - read or get cpfile inode
930 * @sb: super block instance
931 * @cpsize: size of a checkpoint entry
932 * @raw_inode: on-disk cpfile inode
933 * @inodep: buffer to store the inode
934 */
935int nilfs_cpfile_read(struct super_block *sb, size_t cpsize,
936		      struct nilfs_inode *raw_inode, struct inode **inodep)
937{
938	struct inode *cpfile;
939	int err;
 
 
 
 
 
 
 
 
940
941	cpfile = nilfs_iget_locked(sb, NULL, NILFS_CPFILE_INO);
942	if (unlikely(!cpfile))
943		return -ENOMEM;
944	if (!(cpfile->i_state & I_NEW))
945		goto out;
946
947	err = nilfs_mdt_init(cpfile, NILFS_MDT_GFP, 0);
948	if (err)
949		goto failed;
950
951	nilfs_mdt_set_entry_size(cpfile, cpsize,
952				 sizeof(struct nilfs_cpfile_header));
953
954	err = nilfs_read_inode_common(cpfile, raw_inode);
955	if (err)
956		goto failed;
957
958	unlock_new_inode(cpfile);
959 out:
960	*inodep = cpfile;
961	return 0;
962 failed:
963	iget_failed(cpfile);
964	return err;
965}