super.c

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * NILFS module and super block management.
   4 *
   5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   6 *
   7 * Written by Ryusuke Konishi.
   8 */
   9/*
  10 *  linux/fs/ext2/super.c
  11 *
  12 * Copyright (C) 1992, 1993, 1994, 1995
  13 * Remy Card (card@masi.ibp.fr)
  14 * Laboratoire MASI - Institut Blaise Pascal
  15 * Universite Pierre et Marie Curie (Paris VI)
  16 *
  17 *  from
  18 *
  19 *  linux/fs/minix/inode.c
  20 *
  21 *  Copyright (C) 1991, 1992  Linus Torvalds
  22 *
  23 *  Big-endian to little-endian byte-swapping/bitmaps by
  24 *        David S. Miller (davem@caip.rutgers.edu), 1995
  25 */
  26
  27#include <linux/module.h>
  28#include <linux/string.h>
  29#include <linux/slab.h>
  30#include <linux/init.h>
  31#include <linux/blkdev.h>
  32#include <linux/crc32.h>
  33#include <linux/vfs.h>
  34#include <linux/writeback.h>
  35#include <linux/seq_file.h>
  36#include <linux/mount.h>
  37#include <linux/fs_context.h>
  38#include <linux/fs_parser.h>
  39#include "nilfs.h"
  40#include "export.h"
  41#include "mdt.h"
  42#include "alloc.h"
  43#include "btree.h"
  44#include "btnode.h"
  45#include "page.h"
  46#include "cpfile.h"
  47#include "sufile.h" /* nilfs_sufile_resize(), nilfs_sufile_set_alloc_range() */
  48#include "ifile.h"
  49#include "dat.h"
  50#include "segment.h"
  51#include "segbuf.h"
  52
  53MODULE_AUTHOR("NTT Corp.");
  54MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
  55		   "(NILFS)");
  56MODULE_LICENSE("GPL");
  57
  58static struct kmem_cache *nilfs_inode_cachep;
  59struct kmem_cache *nilfs_transaction_cachep;
  60struct kmem_cache *nilfs_segbuf_cachep;
  61struct kmem_cache *nilfs_btree_path_cache;
  62
  63static int nilfs_setup_super(struct super_block *sb, int is_mount);
  64
  65void __nilfs_msg(struct super_block *sb, const char *fmt, ...)
  66{
  67	struct va_format vaf;
  68	va_list args;
  69	int level;
  70
  71	va_start(args, fmt);
  72
  73	level = printk_get_level(fmt);
  74	vaf.fmt = printk_skip_level(fmt);
  75	vaf.va = &args;
  76
  77	if (sb)
  78		printk("%c%cNILFS (%s): %pV\n",
  79		       KERN_SOH_ASCII, level, sb->s_id, &vaf);
  80	else
  81		printk("%c%cNILFS: %pV\n",
  82		       KERN_SOH_ASCII, level, &vaf);
  83
  84	va_end(args);
  85}
  86
  87static void nilfs_set_error(struct super_block *sb)
  88{
  89	struct the_nilfs *nilfs = sb->s_fs_info;
  90	struct nilfs_super_block **sbp;
  91
  92	down_write(&nilfs->ns_sem);
  93	if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
  94		nilfs->ns_mount_state |= NILFS_ERROR_FS;
  95		sbp = nilfs_prepare_super(sb, 0);
  96		if (likely(sbp)) {
  97			sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  98			if (sbp[1])
  99				sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
 100			nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 101		}
 102	}
 103	up_write(&nilfs->ns_sem);
 104}
 105
 106/**
 107 * __nilfs_error() - report failure condition on a filesystem
 108 * @sb:       super block instance
 109 * @function: name of calling function
 110 * @fmt:      format string for message to be output
 111 * @...:      optional arguments to @fmt
 112 *
 113 * __nilfs_error() sets an ERROR_FS flag on the superblock as well as
 114 * reporting an error message.  This function should be called when
 115 * NILFS detects incoherences or defects of meta data on disk.
 116 *
 117 * This implements the body of nilfs_error() macro.  Normally,
 118 * nilfs_error() should be used.  As for sustainable errors such as a
 119 * single-shot I/O error, nilfs_err() should be used instead.
 120 *
 121 * Callers should not add a trailing newline since this will do it.
 122 */
 123void __nilfs_error(struct super_block *sb, const char *function,
 124		   const char *fmt, ...)
 125{
 126	struct the_nilfs *nilfs = sb->s_fs_info;
 127	struct va_format vaf;
 128	va_list args;
 129
 130	va_start(args, fmt);
 131
 132	vaf.fmt = fmt;
 133	vaf.va = &args;
 134
 135	printk(KERN_CRIT "NILFS error (device %s): %s: %pV\n",
 136	       sb->s_id, function, &vaf);
 137
 138	va_end(args);
 139
 140	if (!sb_rdonly(sb)) {
 141		nilfs_set_error(sb);
 142
 143		if (nilfs_test_opt(nilfs, ERRORS_RO)) {
 144			printk(KERN_CRIT "Remounting filesystem read-only\n");
 145			sb->s_flags |= SB_RDONLY;
 146		}
 147	}
 148
 149	if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 150		panic("NILFS (device %s): panic forced after error\n",
 151		      sb->s_id);
 152}
 153
 154struct inode *nilfs_alloc_inode(struct super_block *sb)
 155{
 156	struct nilfs_inode_info *ii;
 157
 158	ii = alloc_inode_sb(sb, nilfs_inode_cachep, GFP_NOFS);
 159	if (!ii)
 160		return NULL;
 161	ii->i_bh = NULL;
 162	ii->i_state = 0;
 163	ii->i_type = 0;
 164	ii->i_cno = 0;
 165	ii->i_assoc_inode = NULL;
 166	ii->i_bmap = &ii->i_bmap_data;
 167	return &ii->vfs_inode;
 168}
 169
 170static void nilfs_free_inode(struct inode *inode)
 171{
 172	if (nilfs_is_metadata_file_inode(inode))
 173		nilfs_mdt_destroy(inode);
 174
 175	kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 176}
 177
 178static int nilfs_sync_super(struct super_block *sb, int flag)
 179{
 180	struct the_nilfs *nilfs = sb->s_fs_info;
 181	int err;
 182
 183 retry:
 184	set_buffer_dirty(nilfs->ns_sbh[0]);
 185	if (nilfs_test_opt(nilfs, BARRIER)) {
 186		err = __sync_dirty_buffer(nilfs->ns_sbh[0],
 187					  REQ_SYNC | REQ_PREFLUSH | REQ_FUA);
 188	} else {
 189		err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 190	}
 191
 192	if (unlikely(err)) {
 193		nilfs_err(sb, "unable to write superblock: err=%d", err);
 194		if (err == -EIO && nilfs->ns_sbh[1]) {
 195			/*
 196			 * sbp[0] points to newer log than sbp[1],
 197			 * so copy sbp[0] to sbp[1] to take over sbp[0].
 198			 */
 199			memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
 200			       nilfs->ns_sbsize);
 201			nilfs_fall_back_super_block(nilfs);
 202			goto retry;
 203		}
 204	} else {
 205		struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 206
 207		nilfs->ns_sbwcount++;
 208
 209		/*
 210		 * The latest segment becomes trailable from the position
 211		 * written in superblock.
 212		 */
 213		clear_nilfs_discontinued(nilfs);
 214
 215		/* update GC protection for recent segments */
 216		if (nilfs->ns_sbh[1]) {
 217			if (flag == NILFS_SB_COMMIT_ALL) {
 218				set_buffer_dirty(nilfs->ns_sbh[1]);
 219				if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
 220					goto out;
 221			}
 222			if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
 223			    le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
 224				sbp = nilfs->ns_sbp[1];
 225		}
 226
 227		spin_lock(&nilfs->ns_last_segment_lock);
 228		nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
 229		spin_unlock(&nilfs->ns_last_segment_lock);
 230	}
 231 out:
 232	return err;
 233}
 234
 235void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
 236			  struct the_nilfs *nilfs)
 237{
 238	sector_t nfreeblocks;
 239
 240	/* nilfs->ns_sem must be locked by the caller. */
 241	nilfs_count_free_blocks(nilfs, &nfreeblocks);
 242	sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
 243
 244	spin_lock(&nilfs->ns_last_segment_lock);
 245	sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
 246	sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
 247	sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
 248	spin_unlock(&nilfs->ns_last_segment_lock);
 249}
 250
 251struct nilfs_super_block **nilfs_prepare_super(struct super_block *sb,
 252					       int flip)
 253{
 254	struct the_nilfs *nilfs = sb->s_fs_info;
 255	struct nilfs_super_block **sbp = nilfs->ns_sbp;
 256
 257	/* nilfs->ns_sem must be locked by the caller. */
 258	if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 259		if (sbp[1] &&
 260		    sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
 261			memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
 262		} else {
 263			nilfs_crit(sb, "superblock broke");
 264			return NULL;
 265		}
 266	} else if (sbp[1] &&
 267		   sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 268		memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 269	}
 270
 271	if (flip && sbp[1])
 272		nilfs_swap_super_block(nilfs);
 273
 274	return sbp;
 275}
 276
 277int nilfs_commit_super(struct super_block *sb, int flag)
 278{
 279	struct the_nilfs *nilfs = sb->s_fs_info;
 280	struct nilfs_super_block **sbp = nilfs->ns_sbp;
 281	time64_t t;
 282
 283	/* nilfs->ns_sem must be locked by the caller. */
 284	t = ktime_get_real_seconds();
 285	nilfs->ns_sbwtime = t;
 286	sbp[0]->s_wtime = cpu_to_le64(t);
 287	sbp[0]->s_sum = 0;
 288	sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 289					     (unsigned char *)sbp[0],
 290					     nilfs->ns_sbsize));
 291	if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
 292		sbp[1]->s_wtime = sbp[0]->s_wtime;
 293		sbp[1]->s_sum = 0;
 294		sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 295					    (unsigned char *)sbp[1],
 296					    nilfs->ns_sbsize));
 297	}
 298	clear_nilfs_sb_dirty(nilfs);
 299	nilfs->ns_flushed_device = 1;
 300	/* make sure store to ns_flushed_device cannot be reordered */
 301	smp_wmb();
 302	return nilfs_sync_super(sb, flag);
 303}
 304
 305/**
 306 * nilfs_cleanup_super() - write filesystem state for cleanup
 307 * @sb: super block instance to be unmounted or degraded to read-only
 308 *
 309 * This function restores state flags in the on-disk super block.
 310 * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
 311 * filesystem was not clean previously.
 312 *
 313 * Return: 0 on success, %-EIO if I/O error or superblock is corrupted.
 314 */
 315int nilfs_cleanup_super(struct super_block *sb)
 316{
 317	struct the_nilfs *nilfs = sb->s_fs_info;
 318	struct nilfs_super_block **sbp;
 319	int flag = NILFS_SB_COMMIT;
 320	int ret = -EIO;
 321
 322	sbp = nilfs_prepare_super(sb, 0);
 323	if (sbp) {
 324		sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
 325		nilfs_set_log_cursor(sbp[0], nilfs);
 326		if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
 327			/*
 328			 * make the "clean" flag also to the opposite
 329			 * super block if both super blocks point to
 330			 * the same checkpoint.
 331			 */
 332			sbp[1]->s_state = sbp[0]->s_state;
 333			flag = NILFS_SB_COMMIT_ALL;
 334		}
 335		ret = nilfs_commit_super(sb, flag);
 336	}
 337	return ret;
 338}
 339
 340/**
 341 * nilfs_move_2nd_super - relocate secondary super block
 342 * @sb: super block instance
 343 * @sb2off: new offset of the secondary super block (in bytes)
 344 *
 345 * Return: 0 on success, or a negative error code on failure.
 346 */
 347static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
 348{
 349	struct the_nilfs *nilfs = sb->s_fs_info;
 350	struct buffer_head *nsbh;
 351	struct nilfs_super_block *nsbp;
 352	sector_t blocknr, newblocknr;
 353	unsigned long offset;
 354	int sb2i;  /* array index of the secondary superblock */
 355	int ret = 0;
 356
 357	/* nilfs->ns_sem must be locked by the caller. */
 358	if (nilfs->ns_sbh[1] &&
 359	    nilfs->ns_sbh[1]->b_blocknr > nilfs->ns_first_data_block) {
 360		sb2i = 1;
 361		blocknr = nilfs->ns_sbh[1]->b_blocknr;
 362	} else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
 363		sb2i = 0;
 364		blocknr = nilfs->ns_sbh[0]->b_blocknr;
 365	} else {
 366		sb2i = -1;
 367		blocknr = 0;
 368	}
 369	if (sb2i >= 0 && (u64)blocknr << nilfs->ns_blocksize_bits == sb2off)
 370		goto out;  /* super block location is unchanged */
 371
 372	/* Get new super block buffer */
 373	newblocknr = sb2off >> nilfs->ns_blocksize_bits;
 374	offset = sb2off & (nilfs->ns_blocksize - 1);
 375	nsbh = sb_getblk(sb, newblocknr);
 376	if (!nsbh) {
 377		nilfs_warn(sb,
 378			   "unable to move secondary superblock to block %llu",
 379			   (unsigned long long)newblocknr);
 380		ret = -EIO;
 381		goto out;
 382	}
 383	nsbp = (void *)nsbh->b_data + offset;
 384
 385	lock_buffer(nsbh);
 386	if (sb2i >= 0) {
 387		/*
 388		 * The position of the second superblock only changes by 4KiB,
 389		 * which is larger than the maximum superblock data size
 390		 * (= 1KiB), so there is no need to use memmove() to allow
 391		 * overlap between source and destination.
 392		 */
 393		memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
 394
 395		/*
 396		 * Zero fill after copy to avoid overwriting in case of move
 397		 * within the same block.
 398		 */
 399		memset(nsbh->b_data, 0, offset);
 400		memset((void *)nsbp + nilfs->ns_sbsize, 0,
 401		       nsbh->b_size - offset - nilfs->ns_sbsize);
 402	} else {
 403		memset(nsbh->b_data, 0, nsbh->b_size);
 404	}
 405	set_buffer_uptodate(nsbh);
 406	unlock_buffer(nsbh);
 407
 408	if (sb2i >= 0) {
 409		brelse(nilfs->ns_sbh[sb2i]);
 410		nilfs->ns_sbh[sb2i] = nsbh;
 411		nilfs->ns_sbp[sb2i] = nsbp;
 412	} else if (nilfs->ns_sbh[0]->b_blocknr < nilfs->ns_first_data_block) {
 413		/* secondary super block will be restored to index 1 */
 414		nilfs->ns_sbh[1] = nsbh;
 415		nilfs->ns_sbp[1] = nsbp;
 416	} else {
 417		brelse(nsbh);
 418	}
 419out:
 420	return ret;
 421}
 422
 423/**
 424 * nilfs_resize_fs - resize the filesystem
 425 * @sb: super block instance
 426 * @newsize: new size of the filesystem (in bytes)
 427 *
 428 * Return: 0 on success, or a negative error code on failure.
 429 */
 430int nilfs_resize_fs(struct super_block *sb, __u64 newsize)
 431{
 432	struct the_nilfs *nilfs = sb->s_fs_info;
 433	struct nilfs_super_block **sbp;
 434	__u64 devsize, newnsegs;
 435	loff_t sb2off;
 436	int ret;
 437
 438	ret = -ERANGE;
 439	devsize = bdev_nr_bytes(sb->s_bdev);
 440	if (newsize > devsize)
 441		goto out;
 442
 443	/*
 444	 * Prevent underflow in second superblock position calculation.
 445	 * The exact minimum size check is done in nilfs_sufile_resize().
 446	 */
 447	if (newsize < 4096) {
 448		ret = -ENOSPC;
 449		goto out;
 450	}
 451
 452	/*
 453	 * Write lock is required to protect some functions depending
 454	 * on the number of segments, the number of reserved segments,
 455	 * and so forth.
 456	 */
 457	down_write(&nilfs->ns_segctor_sem);
 458
 459	sb2off = NILFS_SB2_OFFSET_BYTES(newsize);
 460	newnsegs = sb2off >> nilfs->ns_blocksize_bits;
 461	newnsegs = div64_ul(newnsegs, nilfs->ns_blocks_per_segment);
 462
 463	ret = nilfs_sufile_resize(nilfs->ns_sufile, newnsegs);
 464	up_write(&nilfs->ns_segctor_sem);
 465	if (ret < 0)
 466		goto out;
 467
 468	ret = nilfs_construct_segment(sb);
 469	if (ret < 0)
 470		goto out;
 471
 472	down_write(&nilfs->ns_sem);
 473	nilfs_move_2nd_super(sb, sb2off);
 474	ret = -EIO;
 475	sbp = nilfs_prepare_super(sb, 0);
 476	if (likely(sbp)) {
 477		nilfs_set_log_cursor(sbp[0], nilfs);
 478		/*
 479		 * Drop NILFS_RESIZE_FS flag for compatibility with
 480		 * mount-time resize which may be implemented in a
 481		 * future release.
 482		 */
 483		sbp[0]->s_state = cpu_to_le16(le16_to_cpu(sbp[0]->s_state) &
 484					      ~NILFS_RESIZE_FS);
 485		sbp[0]->s_dev_size = cpu_to_le64(newsize);
 486		sbp[0]->s_nsegments = cpu_to_le64(nilfs->ns_nsegments);
 487		if (sbp[1])
 488			memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 489		ret = nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 490	}
 491	up_write(&nilfs->ns_sem);
 492
 493	/*
 494	 * Reset the range of allocatable segments last.  This order
 495	 * is important in the case of expansion because the secondary
 496	 * superblock must be protected from log write until migration
 497	 * completes.
 498	 */
 499	if (!ret)
 500		nilfs_sufile_set_alloc_range(nilfs->ns_sufile, 0, newnsegs - 1);
 501out:
 502	return ret;
 503}
 504
 505static void nilfs_put_super(struct super_block *sb)
 506{
 507	struct the_nilfs *nilfs = sb->s_fs_info;
 508
 509	nilfs_detach_log_writer(sb);
 510
 511	if (!sb_rdonly(sb)) {
 512		down_write(&nilfs->ns_sem);
 513		nilfs_cleanup_super(sb);
 514		up_write(&nilfs->ns_sem);
 515	}
 516
 517	nilfs_sysfs_delete_device_group(nilfs);
 518	iput(nilfs->ns_sufile);
 519	iput(nilfs->ns_cpfile);
 520	iput(nilfs->ns_dat);
 521
 522	destroy_nilfs(nilfs);
 523	sb->s_fs_info = NULL;
 524}
 525
 526static int nilfs_sync_fs(struct super_block *sb, int wait)
 527{
 528	struct the_nilfs *nilfs = sb->s_fs_info;
 529	struct nilfs_super_block **sbp;
 530	int err = 0;
 531
 532	/* This function is called when super block should be written back */
 533	if (wait)
 534		err = nilfs_construct_segment(sb);
 535
 536	down_write(&nilfs->ns_sem);
 537	if (nilfs_sb_dirty(nilfs)) {
 538		sbp = nilfs_prepare_super(sb, nilfs_sb_will_flip(nilfs));
 539		if (likely(sbp)) {
 540			nilfs_set_log_cursor(sbp[0], nilfs);
 541			nilfs_commit_super(sb, NILFS_SB_COMMIT);
 542		}
 543	}
 544	up_write(&nilfs->ns_sem);
 545
 546	if (!err)
 547		err = nilfs_flush_device(nilfs);
 548
 549	return err;
 550}
 551
 552int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
 553			    struct nilfs_root **rootp)
 554{
 555	struct the_nilfs *nilfs = sb->s_fs_info;
 556	struct nilfs_root *root;
 557	int err = -ENOMEM;
 558
 559	root = nilfs_find_or_create_root(
 560		nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
 561	if (!root)
 562		return err;
 563
 564	if (root->ifile)
 565		goto reuse; /* already attached checkpoint */
 566
 567	down_read(&nilfs->ns_segctor_sem);
 568	err = nilfs_ifile_read(sb, root, cno, nilfs->ns_inode_size);
 569	up_read(&nilfs->ns_segctor_sem);
 570	if (unlikely(err))
 571		goto failed;
 572
 573 reuse:
 574	*rootp = root;
 575	return 0;
 576
 577 failed:
 578	if (err == -EINVAL)
 579		nilfs_err(sb, "Invalid checkpoint (checkpoint number=%llu)",
 580			  (unsigned long long)cno);
 581	nilfs_put_root(root);
 582
 583	return err;
 584}
 585
 586static int nilfs_freeze(struct super_block *sb)
 587{
 588	struct the_nilfs *nilfs = sb->s_fs_info;
 589	int err;
 590
 591	if (sb_rdonly(sb))
 592		return 0;
 593
 594	/* Mark super block clean */
 595	down_write(&nilfs->ns_sem);
 596	err = nilfs_cleanup_super(sb);
 597	up_write(&nilfs->ns_sem);
 598	return err;
 599}
 600
 601static int nilfs_unfreeze(struct super_block *sb)
 602{
 603	struct the_nilfs *nilfs = sb->s_fs_info;
 604
 605	if (sb_rdonly(sb))
 606		return 0;
 607
 608	down_write(&nilfs->ns_sem);
 609	nilfs_setup_super(sb, false);
 610	up_write(&nilfs->ns_sem);
 611	return 0;
 612}
 613
 614static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 615{
 616	struct super_block *sb = dentry->d_sb;
 617	struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
 618	struct the_nilfs *nilfs = root->nilfs;
 619	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 620	unsigned long long blocks;
 621	unsigned long overhead;
 622	unsigned long nrsvblocks;
 623	sector_t nfreeblocks;
 624	u64 nmaxinodes, nfreeinodes;
 625	int err;
 626
 627	/*
 628	 * Compute all of the segment blocks
 629	 *
 630	 * The blocks before first segment and after last segment
 631	 * are excluded.
 632	 */
 633	blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 634		- nilfs->ns_first_data_block;
 635	nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 636
 637	/*
 638	 * Compute the overhead
 639	 *
 640	 * When distributing meta data blocks outside segment structure,
 641	 * We must count them as the overhead.
 642	 */
 643	overhead = 0;
 644
 645	err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 646	if (unlikely(err))
 647		return err;
 648
 649	err = nilfs_ifile_count_free_inodes(root->ifile,
 650					    &nmaxinodes, &nfreeinodes);
 651	if (unlikely(err)) {
 652		nilfs_warn(sb, "failed to count free inodes: err=%d", err);
 653		if (err == -ERANGE) {
 654			/*
 655			 * If nilfs_palloc_count_max_entries() returns
 656			 * -ERANGE error code then we simply treat
 657			 * curent inodes count as maximum possible and
 658			 * zero as free inodes value.
 659			 */
 660			nmaxinodes = atomic64_read(&root->inodes_count);
 661			nfreeinodes = 0;
 662			err = 0;
 663		} else
 664			return err;
 665	}
 666
 667	buf->f_type = NILFS_SUPER_MAGIC;
 668	buf->f_bsize = sb->s_blocksize;
 669	buf->f_blocks = blocks - overhead;
 670	buf->f_bfree = nfreeblocks;
 671	buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 672		(buf->f_bfree - nrsvblocks) : 0;
 673	buf->f_files = nmaxinodes;
 674	buf->f_ffree = nfreeinodes;
 675	buf->f_namelen = NILFS_NAME_LEN;
 676	buf->f_fsid = u64_to_fsid(id);
 677
 678	return 0;
 679}
 680
 681static int nilfs_show_options(struct seq_file *seq, struct dentry *dentry)
 682{
 683	struct super_block *sb = dentry->d_sb;
 684	struct the_nilfs *nilfs = sb->s_fs_info;
 685	struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
 686
 687	if (!nilfs_test_opt(nilfs, BARRIER))
 688		seq_puts(seq, ",nobarrier");
 689	if (root->cno != NILFS_CPTREE_CURRENT_CNO)
 690		seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
 691	if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 692		seq_puts(seq, ",errors=panic");
 693	if (nilfs_test_opt(nilfs, ERRORS_CONT))
 694		seq_puts(seq, ",errors=continue");
 695	if (nilfs_test_opt(nilfs, STRICT_ORDER))
 696		seq_puts(seq, ",order=strict");
 697	if (nilfs_test_opt(nilfs, NORECOVERY))
 698		seq_puts(seq, ",norecovery");
 699	if (nilfs_test_opt(nilfs, DISCARD))
 700		seq_puts(seq, ",discard");
 701
 702	return 0;
 703}
 704
 705static const struct super_operations nilfs_sops = {
 706	.alloc_inode    = nilfs_alloc_inode,
 707	.free_inode     = nilfs_free_inode,
 708	.dirty_inode    = nilfs_dirty_inode,
 709	.evict_inode    = nilfs_evict_inode,
 710	.put_super      = nilfs_put_super,
 711	.sync_fs        = nilfs_sync_fs,
 712	.freeze_fs	= nilfs_freeze,
 713	.unfreeze_fs	= nilfs_unfreeze,
 714	.statfs         = nilfs_statfs,
 715	.show_options = nilfs_show_options
 716};
 717
 718enum {
 719	Opt_err, Opt_barrier, Opt_snapshot, Opt_order, Opt_norecovery,
 720	Opt_discard,
 721};
 722
 723static const struct constant_table nilfs_param_err[] = {
 724	{"continue",	NILFS_MOUNT_ERRORS_CONT},
 725	{"panic",	NILFS_MOUNT_ERRORS_PANIC},
 726	{"remount-ro",	NILFS_MOUNT_ERRORS_RO},
 727	{}
 728};
 729
 730static const struct fs_parameter_spec nilfs_param_spec[] = {
 731	fsparam_enum	("errors", Opt_err, nilfs_param_err),
 732	fsparam_flag_no	("barrier", Opt_barrier),
 733	fsparam_u64	("cp", Opt_snapshot),
 734	fsparam_string	("order", Opt_order),
 735	fsparam_flag	("norecovery", Opt_norecovery),
 736	fsparam_flag_no	("discard", Opt_discard),
 737	{}
 738};
 739
 740struct nilfs_fs_context {
 741	unsigned long ns_mount_opt;
 742	__u64 cno;
 743};
 744
 745static int nilfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
 746{
 747	struct nilfs_fs_context *nilfs = fc->fs_private;
 748	int is_remount = fc->purpose == FS_CONTEXT_FOR_RECONFIGURE;
 749	struct fs_parse_result result;
 750	int opt;
 751
 752	opt = fs_parse(fc, nilfs_param_spec, param, &result);
 753	if (opt < 0)
 754		return opt;
 755
 756	switch (opt) {
 757	case Opt_barrier:
 758		if (result.negated)
 759			nilfs_clear_opt(nilfs, BARRIER);
 760		else
 761			nilfs_set_opt(nilfs, BARRIER);
 762		break;
 763	case Opt_order:
 764		if (strcmp(param->string, "relaxed") == 0)
 765			/* Ordered data semantics */
 766			nilfs_clear_opt(nilfs, STRICT_ORDER);
 767		else if (strcmp(param->string, "strict") == 0)
 768			/* Strict in-order semantics */
 769			nilfs_set_opt(nilfs, STRICT_ORDER);
 770		else
 771			return -EINVAL;
 772		break;
 773	case Opt_err:
 774		nilfs->ns_mount_opt &= ~NILFS_MOUNT_ERROR_MODE;
 775		nilfs->ns_mount_opt |= result.uint_32;
 776		break;
 777	case Opt_snapshot:
 778		if (is_remount) {
 779			struct super_block *sb = fc->root->d_sb;
 780
 781			nilfs_err(sb,
 782				  "\"%s\" option is invalid for remount",
 783				  param->key);
 784			return -EINVAL;
 785		}
 786		if (result.uint_64 == 0) {
 787			nilfs_err(NULL,
 788				  "invalid option \"cp=0\": invalid checkpoint number 0");
 789			return -EINVAL;
 790		}
 791		nilfs->cno = result.uint_64;
 792		break;
 793	case Opt_norecovery:
 794		nilfs_set_opt(nilfs, NORECOVERY);
 795		break;
 796	case Opt_discard:
 797		if (result.negated)
 798			nilfs_clear_opt(nilfs, DISCARD);
 799		else
 800			nilfs_set_opt(nilfs, DISCARD);
 801		break;
 802	default:
 803		return -EINVAL;
 804	}
 805
 806	return 0;
 807}
 808
 809static int nilfs_setup_super(struct super_block *sb, int is_mount)
 810{
 811	struct the_nilfs *nilfs = sb->s_fs_info;
 812	struct nilfs_super_block **sbp;
 813	int max_mnt_count;
 814	int mnt_count;
 815
 816	/* nilfs->ns_sem must be locked by the caller. */
 817	sbp = nilfs_prepare_super(sb, 0);
 818	if (!sbp)
 819		return -EIO;
 820
 821	if (!is_mount)
 822		goto skip_mount_setup;
 823
 824	max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
 825	mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
 826
 827	if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 828		nilfs_warn(sb, "mounting fs with errors");
 829#if 0
 830	} else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 831		nilfs_warn(sb, "maximal mount count reached");
 832#endif
 833	}
 834	if (!max_mnt_count)
 835		sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 836
 837	sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
 838	sbp[0]->s_mtime = cpu_to_le64(ktime_get_real_seconds());
 839
 840skip_mount_setup:
 841	sbp[0]->s_state =
 842		cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
 843	/* synchronize sbp[1] with sbp[0] */
 844	if (sbp[1])
 845		memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 846	return nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 847}
 848
 849struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 850						 u64 pos, int blocksize,
 851						 struct buffer_head **pbh)
 852{
 853	unsigned long long sb_index = pos;
 854	unsigned long offset;
 855
 856	offset = do_div(sb_index, blocksize);
 857	*pbh = sb_bread(sb, sb_index);
 858	if (!*pbh)
 859		return NULL;
 860	return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 861}
 862
 863int nilfs_store_magic(struct super_block *sb,
 864		      struct nilfs_super_block *sbp)
 865{
 866	struct the_nilfs *nilfs = sb->s_fs_info;
 867
 868	sb->s_magic = le16_to_cpu(sbp->s_magic);
 869
 870	/* FS independent flags */
 871#ifdef NILFS_ATIME_DISABLE
 872	sb->s_flags |= SB_NOATIME;
 873#endif
 874
 875	nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
 876	nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
 877	nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
 878	nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
 879
 880	return 0;
 881}
 882
 883int nilfs_check_feature_compatibility(struct super_block *sb,
 884				      struct nilfs_super_block *sbp)
 885{
 886	__u64 features;
 887
 888	features = le64_to_cpu(sbp->s_feature_incompat) &
 889		~NILFS_FEATURE_INCOMPAT_SUPP;
 890	if (features) {
 891		nilfs_err(sb,
 892			  "couldn't mount because of unsupported optional features (%llx)",
 893			  (unsigned long long)features);
 894		return -EINVAL;
 895	}
 896	features = le64_to_cpu(sbp->s_feature_compat_ro) &
 897		~NILFS_FEATURE_COMPAT_RO_SUPP;
 898	if (!sb_rdonly(sb) && features) {
 899		nilfs_err(sb,
 900			  "couldn't mount RDWR because of unsupported optional features (%llx)",
 901			  (unsigned long long)features);
 902		return -EINVAL;
 903	}
 904	return 0;
 905}
 906
 907static int nilfs_get_root_dentry(struct super_block *sb,
 908				 struct nilfs_root *root,
 909				 struct dentry **root_dentry)
 910{
 911	struct inode *inode;
 912	struct dentry *dentry;
 913	int ret = 0;
 914
 915	inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
 916	if (IS_ERR(inode)) {
 917		ret = PTR_ERR(inode);
 918		nilfs_err(sb, "error %d getting root inode", ret);
 919		goto out;
 920	}
 921	if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
 922		iput(inode);
 923		nilfs_err(sb, "corrupt root inode");
 924		ret = -EINVAL;
 925		goto out;
 926	}
 927
 928	if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
 929		dentry = d_find_alias(inode);
 930		if (!dentry) {
 931			dentry = d_make_root(inode);
 932			if (!dentry) {
 933				ret = -ENOMEM;
 934				goto failed_dentry;
 935			}
 936		} else {
 937			iput(inode);
 938		}
 939	} else {
 940		dentry = d_obtain_root(inode);
 941		if (IS_ERR(dentry)) {
 942			ret = PTR_ERR(dentry);
 943			goto failed_dentry;
 944		}
 945	}
 946	*root_dentry = dentry;
 947 out:
 948	return ret;
 949
 950 failed_dentry:
 951	nilfs_err(sb, "error %d getting root dentry", ret);
 952	goto out;
 953}
 954
 955static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 956				 struct dentry **root_dentry)
 957{
 958	struct the_nilfs *nilfs = s->s_fs_info;
 959	struct nilfs_root *root;
 960	int ret;
 961
 962	mutex_lock(&nilfs->ns_snapshot_mount_mutex);
 963
 964	down_read(&nilfs->ns_segctor_sem);
 965	ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
 966	up_read(&nilfs->ns_segctor_sem);
 967	if (ret < 0) {
 968		ret = (ret == -ENOENT) ? -EINVAL : ret;
 969		goto out;
 970	} else if (!ret) {
 971		nilfs_err(s,
 972			  "The specified checkpoint is not a snapshot (checkpoint number=%llu)",
 973			  (unsigned long long)cno);
 974		ret = -EINVAL;
 975		goto out;
 976	}
 977
 978	ret = nilfs_attach_checkpoint(s, cno, false, &root);
 979	if (ret) {
 980		nilfs_err(s,
 981			  "error %d while loading snapshot (checkpoint number=%llu)",
 982			  ret, (unsigned long long)cno);
 983		goto out;
 984	}
 985	ret = nilfs_get_root_dentry(s, root, root_dentry);
 986	nilfs_put_root(root);
 987 out:
 988	mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
 989	return ret;
 990}
 991
 992/**
 993 * nilfs_tree_is_busy() - try to shrink dentries of a checkpoint
 994 * @root_dentry: root dentry of the tree to be shrunk
 995 *
 996 * Return: true if the tree was in-use, false otherwise.
 997 */
 998static bool nilfs_tree_is_busy(struct dentry *root_dentry)
 999{
1000	shrink_dcache_parent(root_dentry);
1001	return d_count(root_dentry) > 1;
1002}
1003
1004int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
1005{
1006	struct the_nilfs *nilfs = sb->s_fs_info;
1007	struct nilfs_root *root;
1008	struct inode *inode;
1009	struct dentry *dentry;
1010	int ret;
1011
1012	if (cno > nilfs->ns_cno)
1013		return false;
1014
1015	if (cno >= nilfs_last_cno(nilfs))
1016		return true;	/* protect recent checkpoints */
1017
1018	ret = false;
1019	root = nilfs_lookup_root(nilfs, cno);
1020	if (root) {
1021		inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
1022		if (inode) {
1023			dentry = d_find_alias(inode);
1024			if (dentry) {
1025				ret = nilfs_tree_is_busy(dentry);
1026				dput(dentry);
1027			}
1028			iput(inode);
1029		}
1030		nilfs_put_root(root);
1031	}
1032	return ret;
1033}
1034
1035/**
1036 * nilfs_fill_super() - initialize a super block instance
1037 * @sb: super_block
1038 * @fc: filesystem context
1039 *
1040 * This function is called exclusively by nilfs->ns_mount_mutex.
1041 * So, the recovery process is protected from other simultaneous mounts.
1042 *
1043 * Return: 0 on success, or a negative error code on failure.
1044 */
1045static int
1046nilfs_fill_super(struct super_block *sb, struct fs_context *fc)
1047{
1048	struct the_nilfs *nilfs;
1049	struct nilfs_root *fsroot;
1050	struct nilfs_fs_context *ctx = fc->fs_private;
1051	__u64 cno;
1052	int err;
1053
1054	nilfs = alloc_nilfs(sb);
1055	if (!nilfs)
1056		return -ENOMEM;
1057
1058	sb->s_fs_info = nilfs;
1059
1060	err = init_nilfs(nilfs, sb);
1061	if (err)
1062		goto failed_nilfs;
1063
1064	/* Copy in parsed mount options */
1065	nilfs->ns_mount_opt = ctx->ns_mount_opt;
1066
1067	sb->s_op = &nilfs_sops;
1068	sb->s_export_op = &nilfs_export_ops;
1069	sb->s_root = NULL;
1070	sb->s_time_gran = 1;
1071	sb->s_max_links = NILFS_LINK_MAX;
1072
1073	sb->s_bdi = bdi_get(sb->s_bdev->bd_disk->bdi);
1074
1075	err = load_nilfs(nilfs, sb);
1076	if (err)
1077		goto failed_nilfs;
1078
1079	super_set_uuid(sb, nilfs->ns_sbp[0]->s_uuid,
1080		       sizeof(nilfs->ns_sbp[0]->s_uuid));
1081	super_set_sysfs_name_bdev(sb);
1082
1083	cno = nilfs_last_cno(nilfs);
1084	err = nilfs_attach_checkpoint(sb, cno, true, &fsroot);
1085	if (err) {
1086		nilfs_err(sb,
1087			  "error %d while loading last checkpoint (checkpoint number=%llu)",
1088			  err, (unsigned long long)cno);
1089		goto failed_unload;
1090	}
1091
1092	if (!sb_rdonly(sb)) {
1093		err = nilfs_attach_log_writer(sb, fsroot);
1094		if (err)
1095			goto failed_checkpoint;
1096	}
1097
1098	err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
1099	if (err)
1100		goto failed_segctor;
1101
1102	nilfs_put_root(fsroot);
1103
1104	if (!sb_rdonly(sb)) {
1105		down_write(&nilfs->ns_sem);
1106		nilfs_setup_super(sb, true);
1107		up_write(&nilfs->ns_sem);
1108	}
1109
1110	return 0;
1111
1112 failed_segctor:
1113	nilfs_detach_log_writer(sb);
1114
1115 failed_checkpoint:
1116	nilfs_put_root(fsroot);
1117
1118 failed_unload:
1119	nilfs_sysfs_delete_device_group(nilfs);
1120	iput(nilfs->ns_sufile);
1121	iput(nilfs->ns_cpfile);
1122	iput(nilfs->ns_dat);
1123
1124 failed_nilfs:
1125	destroy_nilfs(nilfs);
1126	return err;
1127}
1128
1129static int nilfs_reconfigure(struct fs_context *fc)
1130{
1131	struct nilfs_fs_context *ctx = fc->fs_private;
1132	struct super_block *sb = fc->root->d_sb;
1133	struct the_nilfs *nilfs = sb->s_fs_info;
1134	int err;
1135
1136	sync_filesystem(sb);
1137
1138	err = -EINVAL;
1139
1140	if (!nilfs_valid_fs(nilfs)) {
1141		nilfs_warn(sb,
1142			   "couldn't remount because the filesystem is in an incomplete recovery state");
1143		goto ignore_opts;
1144	}
1145	if ((bool)(fc->sb_flags & SB_RDONLY) == sb_rdonly(sb))
1146		goto out;
1147	if (fc->sb_flags & SB_RDONLY) {
1148		sb->s_flags |= SB_RDONLY;
1149
1150		/*
1151		 * Remounting a valid RW partition RDONLY, so set
1152		 * the RDONLY flag and then mark the partition as valid again.
1153		 */
1154		down_write(&nilfs->ns_sem);
1155		nilfs_cleanup_super(sb);
1156		up_write(&nilfs->ns_sem);
1157	} else {
1158		__u64 features;
1159		struct nilfs_root *root;
1160
1161		/*
1162		 * Mounting a RDONLY partition read-write, so reread and
1163		 * store the current valid flag.  (It may have been changed
1164		 * by fsck since we originally mounted the partition.)
1165		 */
1166		down_read(&nilfs->ns_sem);
1167		features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1168			~NILFS_FEATURE_COMPAT_RO_SUPP;
1169		up_read(&nilfs->ns_sem);
1170		if (features) {
1171			nilfs_warn(sb,
1172				   "couldn't remount RDWR because of unsupported optional features (%llx)",
1173				   (unsigned long long)features);
1174			err = -EROFS;
1175			goto ignore_opts;
1176		}
1177
1178		sb->s_flags &= ~SB_RDONLY;
1179
1180		root = NILFS_I(d_inode(sb->s_root))->i_root;
1181		err = nilfs_attach_log_writer(sb, root);
1182		if (err) {
1183			sb->s_flags |= SB_RDONLY;
1184			goto ignore_opts;
1185		}
1186
1187		down_write(&nilfs->ns_sem);
1188		nilfs_setup_super(sb, true);
1189		up_write(&nilfs->ns_sem);
1190	}
1191 out:
1192	sb->s_flags = (sb->s_flags & ~SB_POSIXACL);
1193	/* Copy over parsed remount options */
1194	nilfs->ns_mount_opt = ctx->ns_mount_opt;
1195
1196	return 0;
1197
1198 ignore_opts:
1199	return err;
1200}
1201
1202static int
1203nilfs_get_tree(struct fs_context *fc)
1204{
1205	struct nilfs_fs_context *ctx = fc->fs_private;
1206	struct super_block *s;
1207	dev_t dev;
1208	int err;
1209
1210	if (ctx->cno && !(fc->sb_flags & SB_RDONLY)) {
1211		nilfs_err(NULL,
1212			  "invalid option \"cp=%llu\": read-only option is not specified",
1213			  ctx->cno);
1214		return -EINVAL;
1215	}
1216
1217	err = lookup_bdev(fc->source, &dev);
1218	if (err)
1219		return err;
1220
1221	s = sget_dev(fc, dev);
1222	if (IS_ERR(s))
1223		return PTR_ERR(s);
1224
1225	if (!s->s_root) {
1226		err = setup_bdev_super(s, fc->sb_flags, fc);
1227		if (!err)
1228			err = nilfs_fill_super(s, fc);
1229		if (err)
1230			goto failed_super;
1231
1232		s->s_flags |= SB_ACTIVE;
1233	} else if (!ctx->cno) {
1234		if (nilfs_tree_is_busy(s->s_root)) {
1235			if ((fc->sb_flags ^ s->s_flags) & SB_RDONLY) {
1236				nilfs_err(s,
1237					  "the device already has a %s mount.",
1238					  sb_rdonly(s) ? "read-only" : "read/write");
1239				err = -EBUSY;
1240				goto failed_super;
1241			}
1242		} else {
1243			/*
1244			 * Try reconfigure to setup mount states if the current
1245			 * tree is not mounted and only snapshots use this sb.
1246			 *
1247			 * Since nilfs_reconfigure() requires fc->root to be
1248			 * set, set it first and release it on failure.
1249			 */
1250			fc->root = dget(s->s_root);
1251			err = nilfs_reconfigure(fc);
1252			if (err) {
1253				dput(fc->root);
1254				fc->root = NULL;  /* prevent double release */
1255				goto failed_super;
1256			}
1257			return 0;
1258		}
1259	}
1260
1261	if (ctx->cno) {
1262		struct dentry *root_dentry;
1263
1264		err = nilfs_attach_snapshot(s, ctx->cno, &root_dentry);
1265		if (err)
1266			goto failed_super;
1267		fc->root = root_dentry;
1268		return 0;
1269	}
1270
1271	fc->root = dget(s->s_root);
1272	return 0;
1273
1274 failed_super:
1275	deactivate_locked_super(s);
1276	return err;
1277}
1278
1279static void nilfs_free_fc(struct fs_context *fc)
1280{
1281	kfree(fc->fs_private);
1282}
1283
1284static const struct fs_context_operations nilfs_context_ops = {
1285	.parse_param	= nilfs_parse_param,
1286	.get_tree	= nilfs_get_tree,
1287	.reconfigure	= nilfs_reconfigure,
1288	.free		= nilfs_free_fc,
1289};
1290
1291static int nilfs_init_fs_context(struct fs_context *fc)
1292{
1293	struct nilfs_fs_context *ctx;
1294
1295	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
1296	if (!ctx)
1297		return -ENOMEM;
1298
1299	ctx->ns_mount_opt = NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
1300	fc->fs_private = ctx;
1301	fc->ops = &nilfs_context_ops;
1302
1303	return 0;
1304}
1305
1306struct file_system_type nilfs_fs_type = {
1307	.owner    = THIS_MODULE,
1308	.name     = "nilfs2",
1309	.kill_sb  = kill_block_super,
1310	.fs_flags = FS_REQUIRES_DEV,
1311	.init_fs_context = nilfs_init_fs_context,
1312	.parameters = nilfs_param_spec,
1313};
1314MODULE_ALIAS_FS("nilfs2");
1315
1316static void nilfs_inode_init_once(void *obj)
1317{
1318	struct nilfs_inode_info *ii = obj;
1319
1320	INIT_LIST_HEAD(&ii->i_dirty);
1321#ifdef CONFIG_NILFS_XATTR
1322	init_rwsem(&ii->xattr_sem);
1323#endif
1324	inode_init_once(&ii->vfs_inode);
1325}
1326
1327static void nilfs_segbuf_init_once(void *obj)
1328{
1329	memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1330}
1331
1332static void nilfs_destroy_cachep(void)
1333{
1334	/*
1335	 * Make sure all delayed rcu free inodes are flushed before we
1336	 * destroy cache.
1337	 */
1338	rcu_barrier();
1339
1340	kmem_cache_destroy(nilfs_inode_cachep);
1341	kmem_cache_destroy(nilfs_transaction_cachep);
1342	kmem_cache_destroy(nilfs_segbuf_cachep);
1343	kmem_cache_destroy(nilfs_btree_path_cache);
1344}
1345
1346static int __init nilfs_init_cachep(void)
1347{
1348	nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1349			sizeof(struct nilfs_inode_info), 0,
1350			SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
1351			nilfs_inode_init_once);
1352	if (!nilfs_inode_cachep)
1353		goto fail;
1354
1355	nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1356			sizeof(struct nilfs_transaction_info), 0,
1357			SLAB_RECLAIM_ACCOUNT, NULL);
1358	if (!nilfs_transaction_cachep)
1359		goto fail;
1360
1361	nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1362			sizeof(struct nilfs_segment_buffer), 0,
1363			SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1364	if (!nilfs_segbuf_cachep)
1365		goto fail;
1366
1367	nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1368			sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1369			0, 0, NULL);
1370	if (!nilfs_btree_path_cache)
1371		goto fail;
1372
1373	return 0;
1374
1375fail:
1376	nilfs_destroy_cachep();
1377	return -ENOMEM;
1378}
1379
1380static int __init init_nilfs_fs(void)
1381{
1382	int err;
1383
1384	err = nilfs_init_cachep();
1385	if (err)
1386		goto fail;
1387
1388	err = nilfs_sysfs_init();
1389	if (err)
1390		goto free_cachep;
1391
1392	err = register_filesystem(&nilfs_fs_type);
1393	if (err)
1394		goto deinit_sysfs_entry;
1395
1396	printk(KERN_INFO "NILFS version 2 loaded\n");
1397	return 0;
1398
1399deinit_sysfs_entry:
1400	nilfs_sysfs_exit();
1401free_cachep:
1402	nilfs_destroy_cachep();
1403fail:
1404	return err;
1405}
1406
1407static void __exit exit_nilfs_fs(void)
1408{
1409	nilfs_destroy_cachep();
1410	nilfs_sysfs_exit();
1411	unregister_filesystem(&nilfs_fs_type);
1412}
1413
1414module_init(init_nilfs_fs)
1415module_exit(exit_nilfs_fs)