[linux.git] / fs / nilfs2 / the_nilfs.c

/*
 * the_nilfs.c - the_nilfs shared structure.
 *
 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Written by Ryusuke Konishi <[email protected]>
 *
 */

#include <linux/buffer_head.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/crc32.h>
#include "nilfs.h"
#include "segment.h"
#include "alloc.h"
#include "cpfile.h"
#include "sufile.h"
#include "dat.h"
#include "seglist.h"
#include "segbuf.h"

void nilfs_set_last_segment(struct the_nilfs *nilfs,
			    sector_t start_blocknr, u64 seq, __u64 cno)
{
	spin_lock(&nilfs->ns_last_segment_lock);
	nilfs->ns_last_pseg = start_blocknr;
	nilfs->ns_last_seq = seq;
	nilfs->ns_last_cno = cno;
	spin_unlock(&nilfs->ns_last_segment_lock);
}

/**
 * alloc_nilfs - allocate the_nilfs structure
 * @bdev: block device to which the_nilfs is related
 *
 * alloc_nilfs() allocates memory for the_nilfs and
 * initializes its reference count and locks.
 *
 * Return Value: On success, pointer to the_nilfs is returned.
 * On error, NULL is returned.
 */
struct the_nilfs *alloc_nilfs(struct block_device *bdev)
{
	struct the_nilfs *nilfs;

	nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL);
	if (!nilfs)
		return NULL;

	nilfs->ns_bdev = bdev;
	atomic_set(&nilfs->ns_count, 1);
	atomic_set(&nilfs->ns_writer_refcount, -1);
	atomic_set(&nilfs->ns_ndirtyblks, 0);
	init_rwsem(&nilfs->ns_sem);
	mutex_init(&nilfs->ns_writer_mutex);
	INIT_LIST_HEAD(&nilfs->ns_supers);
	spin_lock_init(&nilfs->ns_last_segment_lock);
	nilfs->ns_gc_inodes_h = NULL;
	init_rwsem(&nilfs->ns_segctor_sem);

	return nilfs;
}

/**
 * put_nilfs - release a reference to the_nilfs
 * @nilfs: the_nilfs structure to be released
 *
 * put_nilfs() decrements a reference counter of the_nilfs.
 * If the reference count reaches zero, the_nilfs is freed.
 */
void put_nilfs(struct the_nilfs *nilfs)
{
	if (!atomic_dec_and_test(&nilfs->ns_count))
		return;
	/*
	 * Increment of ns_count never occur below because the caller
	 * of get_nilfs() holds at least one reference to the_nilfs.
	 * Thus its exclusion control is not required here.
	 */
	might_sleep();
	if (nilfs_loaded(nilfs)) {
		nilfs_mdt_clear(nilfs->ns_sufile);
		nilfs_mdt_destroy(nilfs->ns_sufile);
		nilfs_mdt_clear(nilfs->ns_cpfile);
		nilfs_mdt_destroy(nilfs->ns_cpfile);
		nilfs_mdt_clear(nilfs->ns_dat);
		nilfs_mdt_destroy(nilfs->ns_dat);
		/* XXX: how and when to clear nilfs->ns_gc_dat? */
		nilfs_mdt_destroy(nilfs->ns_gc_dat);
	}
	if (nilfs_init(nilfs)) {
		nilfs_destroy_gccache(nilfs);
		brelse(nilfs->ns_sbh[0]);
		brelse(nilfs->ns_sbh[1]);
	}
	kfree(nilfs);
}

static int nilfs_load_super_root(struct the_nilfs *nilfs,
				 struct nilfs_sb_info *sbi, sector_t sr_block)
{
	static struct lock_class_key dat_lock_key;
	struct buffer_head *bh_sr;
	struct nilfs_super_root *raw_sr;
	struct nilfs_super_block **sbp = nilfs->ns_sbp;
	unsigned dat_entry_size, segment_usage_size, checkpoint_size;
	unsigned inode_size;
	int err;

	err = nilfs_read_super_root_block(sbi->s_super, sr_block, &bh_sr, 1);
	if (unlikely(err))
		return err;

	down_read(&nilfs->ns_sem);
	dat_entry_size = le16_to_cpu(sbp[0]->s_dat_entry_size);
	checkpoint_size = le16_to_cpu(sbp[0]->s_checkpoint_size);
	segment_usage_size = le16_to_cpu(sbp[0]->s_segment_usage_size);
	up_read(&nilfs->ns_sem);

	inode_size = nilfs->ns_inode_size;

	err = -ENOMEM;
	nilfs->ns_dat = nilfs_mdt_new(
		nilfs, NULL, NILFS_DAT_INO, NILFS_DAT_GFP);
	if (unlikely(!nilfs->ns_dat))
		goto failed;

	nilfs->ns_gc_dat = nilfs_mdt_new(
		nilfs, NULL, NILFS_DAT_INO, NILFS_DAT_GFP);
	if (unlikely(!nilfs->ns_gc_dat))
		goto failed_dat;

	nilfs->ns_cpfile = nilfs_mdt_new(
		nilfs, NULL, NILFS_CPFILE_INO, NILFS_CPFILE_GFP);
	if (unlikely(!nilfs->ns_cpfile))
		goto failed_gc_dat;

	nilfs->ns_sufile = nilfs_mdt_new(
		nilfs, NULL, NILFS_SUFILE_INO, NILFS_SUFILE_GFP);
	if (unlikely(!nilfs->ns_sufile))
		goto failed_cpfile;

	err = nilfs_palloc_init_blockgroup(nilfs->ns_dat, dat_entry_size);
	if (unlikely(err))
		goto failed_sufile;

	err = nilfs_palloc_init_blockgroup(nilfs->ns_gc_dat, dat_entry_size);
	if (unlikely(err))
		goto failed_sufile;

	lockdep_set_class(&NILFS_MDT(nilfs->ns_dat)->mi_sem, &dat_lock_key);
	lockdep_set_class(&NILFS_MDT(nilfs->ns_gc_dat)->mi_sem, &dat_lock_key);

	nilfs_mdt_set_shadow(nilfs->ns_dat, nilfs->ns_gc_dat);
	nilfs_mdt_set_entry_size(nilfs->ns_cpfile, checkpoint_size,
				 sizeof(struct nilfs_cpfile_header));
	nilfs_mdt_set_entry_size(nilfs->ns_sufile, segment_usage_size,
				 sizeof(struct nilfs_sufile_header));

	err = nilfs_mdt_read_inode_direct(
		nilfs->ns_dat, bh_sr, NILFS_SR_DAT_OFFSET(inode_size));
	if (unlikely(err))
		goto failed_sufile;

	err = nilfs_mdt_read_inode_direct(
		nilfs->ns_cpfile, bh_sr, NILFS_SR_CPFILE_OFFSET(inode_size));
	if (unlikely(err))
		goto failed_sufile;

	err = nilfs_mdt_read_inode_direct(
		nilfs->ns_sufile, bh_sr, NILFS_SR_SUFILE_OFFSET(inode_size));
	if (unlikely(err))
		goto failed_sufile;

	raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
	nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime);

 failed:
	brelse(bh_sr);
	return err;

 failed_sufile:
	nilfs_mdt_destroy(nilfs->ns_sufile);

 failed_cpfile:
	nilfs_mdt_destroy(nilfs->ns_cpfile);

 failed_gc_dat:
	nilfs_mdt_destroy(nilfs->ns_gc_dat);

 failed_dat:
	nilfs_mdt_destroy(nilfs->ns_dat);
	goto failed;
}

static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri)
{
	memset(ri, 0, sizeof(*ri));
	INIT_LIST_HEAD(&ri->ri_used_segments);
}

static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
{
	nilfs_dispose_segment_list(&ri->ri_used_segments);
}

/**
 * load_nilfs - load and recover the nilfs
 * @nilfs: the_nilfs structure to be released
 * @sbi: nilfs_sb_info used to recover past segment
 *
 * load_nilfs() searches and load the latest super root,
 * attaches the last segment, and does recovery if needed.
 * The caller must call this exclusively for simultaneous mounts.
 */
int load_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
{
	struct nilfs_recovery_info ri;
	unsigned int s_flags = sbi->s_super->s_flags;
	int really_read_only = bdev_read_only(nilfs->ns_bdev);
	unsigned valid_fs;
	int err = 0;

	nilfs_init_recovery_info(&ri);

	down_write(&nilfs->ns_sem);
	valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS);
	up_write(&nilfs->ns_sem);

	if (!valid_fs && (s_flags & MS_RDONLY)) {
		printk(KERN_INFO "NILFS: INFO: recovery "
		       "required for readonly filesystem.\n");
		if (really_read_only) {
			printk(KERN_ERR "NILFS: write access "
			       "unavailable, cannot proceed.\n");
			err = -EROFS;
			goto failed;
		}
		printk(KERN_INFO "NILFS: write access will "
		       "be enabled during recovery.\n");
		sbi->s_super->s_flags &= ~MS_RDONLY;
	}

	err = nilfs_search_super_root(nilfs, sbi, &ri);
	if (unlikely(err)) {
		printk(KERN_ERR "NILFS: error searching super root.\n");
		goto failed;
	}

	err = nilfs_load_super_root(nilfs, sbi, ri.ri_super_root);
	if (unlikely(err)) {
		printk(KERN_ERR "NILFS: error loading super root.\n");
		goto failed;
	}

	if (!valid_fs) {
		err = nilfs_recover_logical_segments(nilfs, sbi, &ri);
		if (unlikely(err)) {
			nilfs_mdt_destroy(nilfs->ns_cpfile);
			nilfs_mdt_destroy(nilfs->ns_sufile);
			nilfs_mdt_destroy(nilfs->ns_dat);
			goto failed;
		}
		if (ri.ri_need_recovery == NILFS_RECOVERY_SR_UPDATED)
			sbi->s_super->s_dirt = 1;
	}

	set_nilfs_loaded(nilfs);

 failed:
	nilfs_clear_recovery_info(&ri);
	sbi->s_super->s_flags = s_flags;
	return err;
}

static unsigned long long nilfs_max_size(unsigned int blkbits)
{
	unsigned int max_bits;
	unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */

	max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */
	if (max_bits < 64)
		res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
	return res;
}

static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
				   struct nilfs_super_block *sbp)
{
	if (le32_to_cpu(sbp->s_rev_level) != NILFS_CURRENT_REV) {
		printk(KERN_ERR "NILFS: revision mismatch "
		       "(superblock rev.=%d.%d, current rev.=%d.%d). "
		       "Please check the version of mkfs.nilfs.\n",
		       le32_to_cpu(sbp->s_rev_level),
		       le16_to_cpu(sbp->s_minor_rev_level),
		       NILFS_CURRENT_REV, NILFS_MINOR_REV);
		return -EINVAL;
	}
	nilfs->ns_sbsize = le16_to_cpu(sbp->s_bytes);
	if (nilfs->ns_sbsize > BLOCK_SIZE)
		return -EINVAL;

	nilfs->ns_inode_size = le16_to_cpu(sbp->s_inode_size);
	nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino);

	nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
	if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) {
		printk(KERN_ERR "NILFS: too short segment. \n");
		return -EINVAL;
	}

	nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block);
	nilfs->ns_nsegments = le64_to_cpu(sbp->s_nsegments);
	nilfs->ns_r_segments_percentage =
		le32_to_cpu(sbp->s_r_segments_percentage);
	nilfs->ns_nrsvsegs =
		max_t(unsigned long, NILFS_MIN_NRSVSEGS,
		      DIV_ROUND_UP(nilfs->ns_nsegments *
				   nilfs->ns_r_segments_percentage, 100));
	nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
	return 0;
}

static int nilfs_valid_sb(struct nilfs_super_block *sbp)
{
	static unsigned char sum[4];
	const int sumoff = offsetof(struct nilfs_super_block, s_sum);
	size_t bytes;
	u32 crc;

	if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC)
		return 0;
	bytes = le16_to_cpu(sbp->s_bytes);
	if (bytes > BLOCK_SIZE)
		return 0;
	crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp,
		       sumoff);
	crc = crc32_le(crc, sum, 4);
	crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4,
		       bytes - sumoff - 4);
	return crc == le32_to_cpu(sbp->s_sum);
}

static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
{
	return offset < ((le64_to_cpu(sbp->s_nsegments) *
			  le32_to_cpu(sbp->s_blocks_per_segment)) <<
			 (le32_to_cpu(sbp->s_log_block_size) + 10));
}

static void nilfs_release_super_block(struct the_nilfs *nilfs)
{
	int i;

	for (i = 0; i < 2; i++) {
		if (nilfs->ns_sbp[i]) {
			brelse(nilfs->ns_sbh[i]);
			nilfs->ns_sbh[i] = NULL;
			nilfs->ns_sbp[i] = NULL;
		}
	}
}

void nilfs_fall_back_super_block(struct the_nilfs *nilfs)
{
	brelse(nilfs->ns_sbh[0]);
	nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
	nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
	nilfs->ns_sbh[1] = NULL;
	nilfs->ns_sbp[1] = NULL;
}

void nilfs_swap_super_block(struct the_nilfs *nilfs)
{
	struct buffer_head *tsbh = nilfs->ns_sbh[0];
	struct nilfs_super_block *tsbp = nilfs->ns_sbp[0];

	nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
	nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
	nilfs->ns_sbh[1] = tsbh;
	nilfs->ns_sbp[1] = tsbp;
}

static int nilfs_load_super_block(struct the_nilfs *nilfs,
				  struct super_block *sb, int blocksize,
				  struct nilfs_super_block **sbpp)
{
	struct nilfs_super_block **sbp = nilfs->ns_sbp;
	struct buffer_head **sbh = nilfs->ns_sbh;
	u64 sb2off = NILFS_SB2_OFFSET_BYTES(nilfs->ns_bdev->bd_inode->i_size);
	int valid[2], swp = 0;

	sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
					&sbh[0]);
	sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]);

	if (!sbp[0]) {
		if (!sbp[1]) {
			printk(KERN_ERR "NILFS: unable to read superblock\n");
			return -EIO;
		}
		printk(KERN_WARNING
		       "NILFS warning: unable to read primary superblock\n");
	} else if (!sbp[1])
		printk(KERN_WARNING
		       "NILFS warning: unable to read secondary superblock\n");

	valid[0] = nilfs_valid_sb(sbp[0]);
	valid[1] = nilfs_valid_sb(sbp[1]);
	swp = valid[1] &&
		(!valid[0] ||
		 le64_to_cpu(sbp[1]->s_wtime) > le64_to_cpu(sbp[0]->s_wtime));

	if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) {
		brelse(sbh[1]);
		sbh[1] = NULL;
		sbp[1] = NULL;
		swp = 0;
	}
	if (!valid[swp]) {
		nilfs_release_super_block(nilfs);
		printk(KERN_ERR "NILFS: Can't find nilfs on dev %s.\n",
		       sb->s_id);
		return -EINVAL;
	}

	if (swp) {
		printk(KERN_WARNING "NILFS warning: broken superblock. "
		       "using spare superblock.\n");
		nilfs_swap_super_block(nilfs);
	}

	nilfs->ns_sbwtime[0] = le64_to_cpu(sbp[0]->s_wtime);
	nilfs->ns_sbwtime[1] = valid[!swp] ? le64_to_cpu(sbp[1]->s_wtime) : 0;
	nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq);
	*sbpp = sbp[0];
	return 0;
}

/**
 * init_nilfs - initialize a NILFS instance.
 * @nilfs: the_nilfs structure
 * @sbi: nilfs_sb_info
 * @sb: super block
 * @data: mount options
 *
 * init_nilfs() performs common initialization per block device (e.g.
 * reading the super block, getting disk layout information, initializing
 * shared fields in the_nilfs). It takes on some portion of the jobs
 * typically done by a fill_super() routine. This division arises from
 * the nature that multiple NILFS instances may be simultaneously
 * mounted on a device.
 * For multiple mounts on the same device, only the first mount
 * invokes these tasks.
 *
 * Return Value: On success, 0 is returned. On error, a negative error
 * code is returned.
 */
int init_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi, char *data)
{
	struct super_block *sb = sbi->s_super;
	struct nilfs_super_block *sbp;
	struct backing_dev_info *bdi;
	int blocksize;
	int err;

	down_write(&nilfs->ns_sem);
	if (nilfs_init(nilfs)) {
		/* Load values from existing the_nilfs */
		sbp = nilfs->ns_sbp[0];
		err = nilfs_store_magic_and_option(sb, sbp, data);
		if (err)
			goto out;

		blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
		if (sb->s_blocksize != blocksize &&
		    !sb_set_blocksize(sb, blocksize)) {
			printk(KERN_ERR "NILFS: blocksize %d unfit to device\n",
			       blocksize);
			err = -EINVAL;
		}
		sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
		goto out;
	}

	blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
	if (!blocksize) {
		printk(KERN_ERR "NILFS: unable to set blocksize\n");
		err = -EINVAL;
		goto out;
	}
	err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
	if (err)
		goto out;

	err = nilfs_store_magic_and_option(sb, sbp, data);
	if (err)
		goto failed_sbh;

	blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
	if (sb->s_blocksize != blocksize) {
		int hw_blocksize = bdev_hardsect_size(sb->s_bdev);

		if (blocksize < hw_blocksize) {
			printk(KERN_ERR
			       "NILFS: blocksize %d too small for device "
			       "(sector-size = %d).\n",
			       blocksize, hw_blocksize);
			err = -EINVAL;
			goto failed_sbh;
		}
		nilfs_release_super_block(nilfs);
		sb_set_blocksize(sb, blocksize);

		err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
		if (err)
			goto out;
			/* not failed_sbh; sbh is released automatically
			   when reloading fails. */
	}
	nilfs->ns_blocksize_bits = sb->s_blocksize_bits;

	err = nilfs_store_disk_layout(nilfs, sbp);
	if (err)
		goto failed_sbh;

	sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);

	nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);

	bdi = nilfs->ns_bdev->bd_inode_backing_dev_info;
	if (!bdi)
		bdi = nilfs->ns_bdev->bd_inode->i_mapping->backing_dev_info;
	nilfs->ns_bdi = bdi ? : &default_backing_dev_info;

	/* Finding last segment */
	nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg);
	nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno);
	nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq);

	nilfs->ns_seg_seq = nilfs->ns_last_seq;
	nilfs->ns_segnum =
		nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg);
	nilfs->ns_cno = nilfs->ns_last_cno + 1;
	if (nilfs->ns_segnum >= nilfs->ns_nsegments) {
		printk(KERN_ERR "NILFS invalid last segment number.\n");
		err = -EINVAL;
		goto failed_sbh;
	}
	/* Dummy values  */
	nilfs->ns_free_segments_count =
		nilfs->ns_nsegments - (nilfs->ns_segnum + 1);

	/* Initialize gcinode cache */
	err = nilfs_init_gccache(nilfs);
	if (err)
		goto failed_sbh;

	set_nilfs_init(nilfs);
	err = 0;
 out:
	up_write(&nilfs->ns_sem);
	return err;

 failed_sbh:
	nilfs_release_super_block(nilfs);
	goto out;
}

int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
{
	struct inode *dat = nilfs_dat_inode(nilfs);
	unsigned long ncleansegs;
	int err;

	down_read(&NILFS_MDT(dat)->mi_sem);	/* XXX */
	err = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile, &ncleansegs);
	up_read(&NILFS_MDT(dat)->mi_sem);	/* XXX */
	if (likely(!err))
		*nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment;
	return err;
}

int nilfs_near_disk_full(struct the_nilfs *nilfs)
{
	struct inode *sufile = nilfs->ns_sufile;
	unsigned long ncleansegs, nincsegs;
	int ret;

	ret = nilfs_sufile_get_ncleansegs(sufile, &ncleansegs);
	if (likely(!ret)) {
		nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
			nilfs->ns_blocks_per_segment + 1;
		if (ncleansegs <= nilfs->ns_nrsvsegs + nincsegs)
			ret++;
	}
	return ret;
}

int nilfs_checkpoint_is_mounted(struct the_nilfs *nilfs, __u64 cno,
				int snapshot_mount)
{
	struct nilfs_sb_info *sbi;
	int ret = 0;

	down_read(&nilfs->ns_sem);
	if (cno == 0 || cno > nilfs->ns_cno)
		goto out_unlock;

	list_for_each_entry(sbi, &nilfs->ns_supers, s_list) {
		if (sbi->s_snapshot_cno == cno &&
		    (!snapshot_mount || nilfs_test_opt(sbi, SNAPSHOT))) {
					/* exclude read-only mounts */
			ret++;
			break;
		}
	}
	/* for protecting recent checkpoints */
	if (cno >= nilfs_last_cno(nilfs))
		ret++;

 out_unlock:
	up_read(&nilfs->ns_sem);
	return ret;
}
Commit	Line	Data
8a9d2191 RK	1	/*
	2	* the_nilfs.c - the_nilfs shared structure.
	3	*
	4	* Copyright (C) 2005-2008 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 Ryusuke Konishi <[email protected]>
	21	*
	22	*/
	23
	24	#include <linux/buffer_head.h>
	25	#include <linux/slab.h>
	26	#include <linux/blkdev.h>
	27	#include <linux/backing-dev.h>
e339ad31	28	#include <linux/crc32.h>
8a9d2191 RK	29	#include "nilfs.h"
	30	#include "segment.h"
	31	#include "alloc.h"
	32	#include "cpfile.h"
	33	#include "sufile.h"
	34	#include "dat.h"
	35	#include "seglist.h"
	36	#include "segbuf.h"
	37
	38	void nilfs_set_last_segment(struct the_nilfs *nilfs,
	39	sector_t start_blocknr, u64 seq, __u64 cno)
	40	{
	41	spin_lock(&nilfs->ns_last_segment_lock);
	42	nilfs->ns_last_pseg = start_blocknr;
	43	nilfs->ns_last_seq = seq;
	44	nilfs->ns_last_cno = cno;
	45	spin_unlock(&nilfs->ns_last_segment_lock);
	46	}
	47
	48	/**
	49	* alloc_nilfs - allocate the_nilfs structure
	50	* @bdev: block device to which the_nilfs is related
	51	*
	52	* alloc_nilfs() allocates memory for the_nilfs and
	53	* initializes its reference count and locks.
	54	*
	55	* Return Value: On success, pointer to the_nilfs is returned.
	56	* On error, NULL is returned.
	57	*/
	58	struct the_nilfs alloc_nilfs(struct block_device bdev)
	59	{
	60	struct the_nilfs *nilfs;
	61
	62	nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL);
	63	if (!nilfs)
	64	return NULL;
	65
	66	nilfs->ns_bdev = bdev;
	67	atomic_set(&nilfs->ns_count, 1);
	68	atomic_set(&nilfs->ns_writer_refcount, -1);
	69	atomic_set(&nilfs->ns_ndirtyblks, 0);
	70	init_rwsem(&nilfs->ns_sem);
	71	mutex_init(&nilfs->ns_writer_mutex);
	72	INIT_LIST_HEAD(&nilfs->ns_supers);
	73	spin_lock_init(&nilfs->ns_last_segment_lock);
	74	nilfs->ns_gc_inodes_h = NULL;
8a9d2191	75	init_rwsem(&nilfs->ns_segctor_sem);
8a9d2191 RK	76
	77	return nilfs;
	78	}
	79
	80	/**
	81	* put_nilfs - release a reference to the_nilfs
	82	* @nilfs: the_nilfs structure to be released
	83	*
	84	* put_nilfs() decrements a reference counter of the_nilfs.
	85	* If the reference count reaches zero, the_nilfs is freed.
	86	*/
	87	void put_nilfs(struct the_nilfs *nilfs)
	88	{
	89	if (!atomic_dec_and_test(&nilfs->ns_count))
	90	return;
	91	/*
	92	* Increment of ns_count never occur below because the caller
	93	* of get_nilfs() holds at least one reference to the_nilfs.
	94	* Thus its exclusion control is not required here.
	95	*/
	96	might_sleep();
	97	if (nilfs_loaded(nilfs)) {
8a9d2191 RK	98	nilfs_mdt_clear(nilfs->ns_sufile);
	99	nilfs_mdt_destroy(nilfs->ns_sufile);
	100	nilfs_mdt_clear(nilfs->ns_cpfile);
	101	nilfs_mdt_destroy(nilfs->ns_cpfile);
	102	nilfs_mdt_clear(nilfs->ns_dat);
	103	nilfs_mdt_destroy(nilfs->ns_dat);
	104	/* XXX: how and when to clear nilfs->ns_gc_dat? */
	105	nilfs_mdt_destroy(nilfs->ns_gc_dat);
	106	}
	107	if (nilfs_init(nilfs)) {
	108	nilfs_destroy_gccache(nilfs);
e339ad31 RK	109	brelse(nilfs->ns_sbh[0]);
e339ad31 RK	110	brelse(nilfs->ns_sbh[1]);
8a9d2191 RK	111	}
	112	kfree(nilfs);
	113	}
	114
	115	static int nilfs_load_super_root(struct the_nilfs *nilfs,
	116	struct nilfs_sb_info *sbi, sector_t sr_block)
	117	{
c2698e50	118	static struct lock_class_key dat_lock_key;
8a9d2191 RK	119	struct buffer_head *bh_sr;
8a9d2191 RK	120	struct nilfs_super_root *raw_sr;
e339ad31	121	struct nilfs_super_block **sbp = nilfs->ns_sbp;
8a9d2191 RK	122	unsigned dat_entry_size, segment_usage_size, checkpoint_size;
	123	unsigned inode_size;
	124	int err;
	125
	126	err = nilfs_read_super_root_block(sbi->s_super, sr_block, &bh_sr, 1);
	127	if (unlikely(err))
	128	return err;
	129
	130	down_read(&nilfs->ns_sem);
e339ad31 RK	131	dat_entry_size = le16_to_cpu(sbp[0]->s_dat_entry_size);
	132	checkpoint_size = le16_to_cpu(sbp[0]->s_checkpoint_size);
	133	segment_usage_size = le16_to_cpu(sbp[0]->s_segment_usage_size);
8a9d2191 RK	134	up_read(&nilfs->ns_sem);
	135
	136	inode_size = nilfs->ns_inode_size;
	137
	138	err = -ENOMEM;
	139	nilfs->ns_dat = nilfs_mdt_new(
	140	nilfs, NULL, NILFS_DAT_INO, NILFS_DAT_GFP);
	141	if (unlikely(!nilfs->ns_dat))
	142	goto failed;
	143
	144	nilfs->ns_gc_dat = nilfs_mdt_new(
	145	nilfs, NULL, NILFS_DAT_INO, NILFS_DAT_GFP);
	146	if (unlikely(!nilfs->ns_gc_dat))
	147	goto failed_dat;
	148
	149	nilfs->ns_cpfile = nilfs_mdt_new(
	150	nilfs, NULL, NILFS_CPFILE_INO, NILFS_CPFILE_GFP);
	151	if (unlikely(!nilfs->ns_cpfile))
	152	goto failed_gc_dat;
	153
	154	nilfs->ns_sufile = nilfs_mdt_new(
	155	nilfs, NULL, NILFS_SUFILE_INO, NILFS_SUFILE_GFP);
	156	if (unlikely(!nilfs->ns_sufile))
	157	goto failed_cpfile;
	158
	159	err = nilfs_palloc_init_blockgroup(nilfs->ns_dat, dat_entry_size);
	160	if (unlikely(err))
	161	goto failed_sufile;
	162
	163	err = nilfs_palloc_init_blockgroup(nilfs->ns_gc_dat, dat_entry_size);
	164	if (unlikely(err))
	165	goto failed_sufile;
	166
c2698e50 RK	167	lockdep_set_class(&NILFS_MDT(nilfs->ns_dat)->mi_sem, &dat_lock_key);
	168	lockdep_set_class(&NILFS_MDT(nilfs->ns_gc_dat)->mi_sem, &dat_lock_key);
	169
8a9d2191 RK	170	nilfs_mdt_set_shadow(nilfs->ns_dat, nilfs->ns_gc_dat);
	171	nilfs_mdt_set_entry_size(nilfs->ns_cpfile, checkpoint_size,
	172	sizeof(struct nilfs_cpfile_header));
	173	nilfs_mdt_set_entry_size(nilfs->ns_sufile, segment_usage_size,
	174	sizeof(struct nilfs_sufile_header));
	175
	176	err = nilfs_mdt_read_inode_direct(
	177	nilfs->ns_dat, bh_sr, NILFS_SR_DAT_OFFSET(inode_size));
	178	if (unlikely(err))
	179	goto failed_sufile;
	180
	181	err = nilfs_mdt_read_inode_direct(
	182	nilfs->ns_cpfile, bh_sr, NILFS_SR_CPFILE_OFFSET(inode_size));
	183	if (unlikely(err))
	184	goto failed_sufile;
	185
	186	err = nilfs_mdt_read_inode_direct(
	187	nilfs->ns_sufile, bh_sr, NILFS_SR_SUFILE_OFFSET(inode_size));
	188	if (unlikely(err))
	189	goto failed_sufile;
	190
	191	raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
	192	nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime);
	193
	194	failed:
	195	brelse(bh_sr);
	196	return err;
	197
	198	failed_sufile:
	199	nilfs_mdt_destroy(nilfs->ns_sufile);
	200
	201	failed_cpfile:
	202	nilfs_mdt_destroy(nilfs->ns_cpfile);
	203
	204	failed_gc_dat:
	205	nilfs_mdt_destroy(nilfs->ns_gc_dat);
	206
	207	failed_dat:
	208	nilfs_mdt_destroy(nilfs->ns_dat);
	209	goto failed;
	210	}
	211
	212	static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri)
	213	{
	214	memset(ri, 0, sizeof(*ri));
	215	INIT_LIST_HEAD(&ri->ri_used_segments);
	216	}
	217
	218	static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
	219	{
	220	nilfs_dispose_segment_list(&ri->ri_used_segments);
	221	}
	222
	223	/**
	224	* load_nilfs - load and recover the nilfs
	225	* @nilfs: the_nilfs structure to be released
	226	* @sbi: nilfs_sb_info used to recover past segment
	227	*
	228	* load_nilfs() searches and load the latest super root,
	229	* attaches the last segment, and does recovery if needed.
	230	* The caller must call this exclusively for simultaneous mounts.
	231	*/
	232	int load_nilfs(struct the_nilfs nilfs, struct nilfs_sb_info sbi)
	233	{
234	struct nilfs_recovery_info ri;
235	unsigned int s_flags = sbi->s_super->s_flags;
236	int really_read_only = bdev_read_only(nilfs->ns_bdev);
237	unsigned valid_fs;
238	int err = 0;
239
240	nilfs_init_recovery_info(&ri);
241
242	down_write(&nilfs->ns_sem);
243	valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS);
244	up_write(&nilfs->ns_sem);
245
246	if (!valid_fs && (s_flags & MS_RDONLY)) {
247	printk(KERN_INFO "NILFS: INFO: recovery "
248	"required for readonly filesystem.\n");
249	if (really_read_only) {
250	printk(KERN_ERR "NILFS: write access "
251	"unavailable, cannot proceed.\n");
252	err = -EROFS;
253	goto failed;
254	}
255	printk(KERN_INFO "NILFS: write access will "
256	"be enabled during recovery.\n");
257	sbi->s_super->s_flags &= ~MS_RDONLY;
258	}
259
260	err = nilfs_search_super_root(nilfs, sbi, &ri);
261	if (unlikely(err)) {
262	printk(KERN_ERR "NILFS: error searching super root.\n");
263	goto failed;
264	}
265
266	err = nilfs_load_super_root(nilfs, sbi, ri.ri_super_root);
267	if (unlikely(err)) {
268	printk(KERN_ERR "NILFS: error loading super root.\n");
269	goto failed;
270	}
271
272	if (!valid_fs) {
273	err = nilfs_recover_logical_segments(nilfs, sbi, &ri);
274	if (unlikely(err)) {
275	nilfs_mdt_destroy(nilfs->ns_cpfile);
276	nilfs_mdt_destroy(nilfs->ns_sufile);
277	nilfs_mdt_destroy(nilfs->ns_dat);
278	goto failed;
279	}
e339ad31 RK	280	if (ri.ri_need_recovery == NILFS_RECOVERY_SR_UPDATED)
e339ad31 RK	281	sbi->s_super->s_dirt = 1;
8a9d2191 RK	282	}
	283
	284	set_nilfs_loaded(nilfs);
	285
	286	failed:
	287	nilfs_clear_recovery_info(&ri);
	288	sbi->s_super->s_flags = s_flags;
	289	return err;
	290	}
	291
	292	static unsigned long long nilfs_max_size(unsigned int blkbits)
	293	{
	294	unsigned int max_bits;
	295	unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */
	296
	297	max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */
	298	if (max_bits < 64)
	299	res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
	300	return res;
	301	}
	302
e339ad31 RK	303	static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
e339ad31 RK	304	struct nilfs_super_block *sbp)
8a9d2191 RK	305	{
	306	if (le32_to_cpu(sbp->s_rev_level) != NILFS_CURRENT_REV) {
	307	printk(KERN_ERR "NILFS: revision mismatch "
	308	"(superblock rev.=%d.%d, current rev.=%d.%d). "
	309	"Please check the version of mkfs.nilfs.\n",
	310	le32_to_cpu(sbp->s_rev_level),
	311	le16_to_cpu(sbp->s_minor_rev_level),
	312	NILFS_CURRENT_REV, NILFS_MINOR_REV);
	313	return -EINVAL;
	314	}
e339ad31 RK	315	nilfs->ns_sbsize = le16_to_cpu(sbp->s_bytes);
	316	if (nilfs->ns_sbsize > BLOCK_SIZE)
	317	return -EINVAL;
	318
8a9d2191 RK	319	nilfs->ns_inode_size = le16_to_cpu(sbp->s_inode_size);
	320	nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino);
	321
	322	nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
	323	if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) {
	324	printk(KERN_ERR "NILFS: too short segment. \n");
	325	return -EINVAL;
	326	}
	327
	328	nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block);
	329	nilfs->ns_nsegments = le64_to_cpu(sbp->s_nsegments);
	330	nilfs->ns_r_segments_percentage =
	331	le32_to_cpu(sbp->s_r_segments_percentage);
	332	nilfs->ns_nrsvsegs =
	333	max_t(unsigned long, NILFS_MIN_NRSVSEGS,
	334	DIV_ROUND_UP(nilfs->ns_nsegments *
	335	nilfs->ns_r_segments_percentage, 100));
	336	nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
	337	return 0;
	338	}
	339
e339ad31 RK	340	static int nilfs_valid_sb(struct nilfs_super_block *sbp)
	341	{
	342	static unsigned char sum[4];
	343	const int sumoff = offsetof(struct nilfs_super_block, s_sum);
	344	size_t bytes;
	345	u32 crc;
	346
	347	if (!sbp \|\| le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC)
	348	return 0;
	349	bytes = le16_to_cpu(sbp->s_bytes);
	350	if (bytes > BLOCK_SIZE)
	351	return 0;
	352	crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp,
	353	sumoff);
	354	crc = crc32_le(crc, sum, 4);
	355	crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4,
	356	bytes - sumoff - 4);
	357	return crc == le32_to_cpu(sbp->s_sum);
	358	}
	359
	360	static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
	361	{
	362	return offset < ((le64_to_cpu(sbp->s_nsegments) *
	363	le32_to_cpu(sbp->s_blocks_per_segment)) <<
	364	(le32_to_cpu(sbp->s_log_block_size) + 10));
	365	}
	366
	367	static void nilfs_release_super_block(struct the_nilfs *nilfs)
	368	{
	369	int i;
	370
	371	for (i = 0; i < 2; i++) {
	372	if (nilfs->ns_sbp[i]) {
	373	brelse(nilfs->ns_sbh[i]);
	374	nilfs->ns_sbh[i] = NULL;
	375	nilfs->ns_sbp[i] = NULL;
	376	}
	377	}
	378	}
	379
	380	void nilfs_fall_back_super_block(struct the_nilfs *nilfs)
	381	{
	382	brelse(nilfs->ns_sbh[0]);
	383	nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
	384	nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
	385	nilfs->ns_sbh[1] = NULL;
	386	nilfs->ns_sbp[1] = NULL;
	387	}
	388
	389	void nilfs_swap_super_block(struct the_nilfs *nilfs)
	390	{
	391	struct buffer_head *tsbh = nilfs->ns_sbh[0];
	392	struct nilfs_super_block *tsbp = nilfs->ns_sbp[0];
	393
	394	nilfs->ns_sbh[0] = nilfs->ns_sbh[1];
	395	nilfs->ns_sbp[0] = nilfs->ns_sbp[1];
	396	nilfs->ns_sbh[1] = tsbh;
	397	nilfs->ns_sbp[1] = tsbp;
	398	}
	399
	400	static int nilfs_load_super_block(struct the_nilfs *nilfs,
	401	struct super_block *sb, int blocksize,
	402	struct nilfs_super_block **sbpp)
	403	{
404	struct nilfs_super_block **sbp = nilfs->ns_sbp;
405	struct buffer_head **sbh = nilfs->ns_sbh;
406	u64 sb2off = NILFS_SB2_OFFSET_BYTES(nilfs->ns_bdev->bd_inode->i_size);
407	int valid[2], swp = 0;
408
409	sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
410	&sbh[0]);
411	sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]);
412
413	if (!sbp[0]) {
414	if (!sbp[1]) {
415	printk(KERN_ERR "NILFS: unable to read superblock\n");
416	return -EIO;
417	}
418	printk(KERN_WARNING
419	"NILFS warning: unable to read primary superblock\n");
420	} else if (!sbp[1])
421	printk(KERN_WARNING
422	"NILFS warning: unable to read secondary superblock\n");
423
424	valid[0] = nilfs_valid_sb(sbp[0]);
425	valid[1] = nilfs_valid_sb(sbp[1]);
426	swp = valid[1] &&
427	(!valid[0] \|\|
428	le64_to_cpu(sbp[1]->s_wtime) > le64_to_cpu(sbp[0]->s_wtime));
429
430	if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) {
431	brelse(sbh[1]);
432	sbh[1] = NULL;
433	sbp[1] = NULL;
434	swp = 0;
435	}
436	if (!valid[swp]) {
437	nilfs_release_super_block(nilfs);
438	printk(KERN_ERR "NILFS: Can't find nilfs on dev %s.\n",
439	sb->s_id);
440	return -EINVAL;
441	}
442
443	if (swp) {
444	printk(KERN_WARNING "NILFS warning: broken superblock. "
445	"using spare superblock.\n");
446	nilfs_swap_super_block(nilfs);
447	}
448
449	nilfs->ns_sbwtime[0] = le64_to_cpu(sbp[0]->s_wtime);
450	nilfs->ns_sbwtime[1] = valid[!swp] ? le64_to_cpu(sbp[1]->s_wtime) : 0;
451	nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq);
452	*sbpp = sbp[0];
453	return 0;
454	}
455
8a9d2191 RK	456	/**
	457	* init_nilfs - initialize a NILFS instance.
	458	* @nilfs: the_nilfs structure
	459	* @sbi: nilfs_sb_info
	460	* @sb: super block
	461	* @data: mount options
	462	*
	463	* init_nilfs() performs common initialization per block device (e.g.
	464	* reading the super block, getting disk layout information, initializing
	465	* shared fields in the_nilfs). It takes on some portion of the jobs
	466	* typically done by a fill_super() routine. This division arises from
	467	* the nature that multiple NILFS instances may be simultaneously
	468	* mounted on a device.
	469	* For multiple mounts on the same device, only the first mount
	470	* invokes these tasks.
	471	*
	472	* Return Value: On success, 0 is returned. On error, a negative error
	473	* code is returned.
	474	*/
	475	int init_nilfs(struct the_nilfs nilfs, struct nilfs_sb_info sbi, char *data)
	476	{
	477	struct super_block *sb = sbi->s_super;
8a9d2191 RK	478	struct nilfs_super_block *sbp;
	479	struct backing_dev_info *bdi;
	480	int blocksize;
e339ad31	481	int err;
8a9d2191 RK	482
	483	down_write(&nilfs->ns_sem);
	484	if (nilfs_init(nilfs)) {
	485	/* Load values from existing the_nilfs */
e339ad31	486	sbp = nilfs->ns_sbp[0];
8a9d2191 RK	487	err = nilfs_store_magic_and_option(sb, sbp, data);
	488	if (err)
	489	goto out;
	490
	491	blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
	492	if (sb->s_blocksize != blocksize &&
	493	!sb_set_blocksize(sb, blocksize)) {
	494	printk(KERN_ERR "NILFS: blocksize %d unfit to device\n",
	495	blocksize);
	496	err = -EINVAL;
	497	}
	498	sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
	499	goto out;
	500	}
	501
e339ad31 RK	502	blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
	503	if (!blocksize) {
	504	printk(KERN_ERR "NILFS: unable to set blocksize\n");
8a9d2191 RK	505	err = -EINVAL;
	506	goto out;
	507	}
e339ad31 RK	508	err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
	509	if (err)
	510	goto out;
	511
8a9d2191 RK	512	err = nilfs_store_magic_and_option(sb, sbp, data);
	513	if (err)
	514	goto failed_sbh;
	515
	516	blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
	517	if (sb->s_blocksize != blocksize) {
e339ad31 RK	518	int hw_blocksize = bdev_hardsect_size(sb->s_bdev);
	519
	520	if (blocksize < hw_blocksize) {
	521	printk(KERN_ERR
	522	"NILFS: blocksize %d too small for device "
	523	"(sector-size = %d).\n",
	524	blocksize, hw_blocksize);
8a9d2191	525	err = -EINVAL;
e339ad31 RK	526	goto failed_sbh;
	527	}
	528	nilfs_release_super_block(nilfs);
	529	sb_set_blocksize(sb, blocksize);
	530
	531	err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp);
	532	if (err)
8a9d2191 RK	533	goto out;
	534	/* not failed_sbh; sbh is released automatically
	535	when reloading fails. */
8a9d2191 RK	536	}
	537	nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
	538
e339ad31	539	err = nilfs_store_disk_layout(nilfs, sbp);
8a9d2191 RK	540	if (err)
	541	goto failed_sbh;
	542
	543	sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
	544
	545	nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
8a9d2191 RK	546
	547	bdi = nilfs->ns_bdev->bd_inode_backing_dev_info;
	548	if (!bdi)
	549	bdi = nilfs->ns_bdev->bd_inode->i_mapping->backing_dev_info;
	550	nilfs->ns_bdi = bdi ? : &default_backing_dev_info;
	551
	552	/* Finding last segment */
	553	nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg);
	554	nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno);
	555	nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq);
	556
	557	nilfs->ns_seg_seq = nilfs->ns_last_seq;
	558	nilfs->ns_segnum =
	559	nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg);
	560	nilfs->ns_cno = nilfs->ns_last_cno + 1;
	561	if (nilfs->ns_segnum >= nilfs->ns_nsegments) {
	562	printk(KERN_ERR "NILFS invalid last segment number.\n");
	563	err = -EINVAL;
	564	goto failed_sbh;
	565	}
	566	/* Dummy values */
	567	nilfs->ns_free_segments_count =
	568	nilfs->ns_nsegments - (nilfs->ns_segnum + 1);
	569
	570	/* Initialize gcinode cache */
	571	err = nilfs_init_gccache(nilfs);
	572	if (err)
	573	goto failed_sbh;
	574
	575	set_nilfs_init(nilfs);
	576	err = 0;
	577	out:
	578	up_write(&nilfs->ns_sem);
	579	return err;
	580
	581	failed_sbh:
e339ad31	582	nilfs_release_super_block(nilfs);
8a9d2191 RK	583	goto out;
	584	}
	585
	586	int nilfs_count_free_blocks(struct the_nilfs nilfs, sector_t nblocks)
	587	{
	588	struct inode *dat = nilfs_dat_inode(nilfs);
	589	unsigned long ncleansegs;
	590	int err;
	591
	592	down_read(&NILFS_MDT(dat)->mi_sem); /* XXX */
	593	err = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile, &ncleansegs);
	594	up_read(&NILFS_MDT(dat)->mi_sem); /* XXX */
	595	if (likely(!err))
	596	nblocks = (sector_t)ncleansegs nilfs->ns_blocks_per_segment;
	597	return err;
	598	}
	599
8a9d2191 RK	600	int nilfs_near_disk_full(struct the_nilfs *nilfs)
	601	{
	602	struct inode *sufile = nilfs->ns_sufile;
	603	unsigned long ncleansegs, nincsegs;
	604	int ret;
	605
	606	ret = nilfs_sufile_get_ncleansegs(sufile, &ncleansegs);
	607	if (likely(!ret)) {
	608	nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
	609	nilfs->ns_blocks_per_segment + 1;
	610	if (ncleansegs <= nilfs->ns_nrsvsegs + nincsegs)
	611	ret++;
	612	}
	613	return ret;
	614	}
	615
	616	int nilfs_checkpoint_is_mounted(struct the_nilfs *nilfs, __u64 cno,
	617	int snapshot_mount)
	618	{
	619	struct nilfs_sb_info *sbi;
	620	int ret = 0;
	621
	622	down_read(&nilfs->ns_sem);
	623	if (cno == 0 \|\| cno > nilfs->ns_cno)
	624	goto out_unlock;
	625
	626	list_for_each_entry(sbi, &nilfs->ns_supers, s_list) {
	627	if (sbi->s_snapshot_cno == cno &&
	628	(!snapshot_mount \|\| nilfs_test_opt(sbi, SNAPSHOT))) {
	629	/* exclude read-only mounts */
	630	ret++;
	631	break;
	632	}
	633	}
	634	/* for protecting recent checkpoints */
	635	if (cno >= nilfs_last_cno(nilfs))
	636	ret++;
	637
	638	out_unlock:
	639	up_read(&nilfs->ns_sem);
	640	return ret;
	641	}