- 根目录:
- fs
- nilfs2
- super.c
/*
* super.c - NILFS module and super block management.
*
* 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 <ryusuke@osrg.net>
*/
/*
* linux/fs/ext2/super.c
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/inode.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* Big-endian to little-endian byte-swapping/bitmaps by
* David S. Miller (davem@caip.rutgers.edu), 1995
*/
#include <linux/module.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/parser.h>
#include <linux/crc32.h>
#include <linux/vfs.h>
#include <linux/writeback.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include "nilfs.h"
#include "export.h"
#include "mdt.h"
#include "alloc.h"
#include "btree.h"
#include "btnode.h"
#include "page.h"
#include "cpfile.h"
#include "ifile.h"
#include "dat.h"
#include "segment.h"
#include "segbuf.h"
MODULE_AUTHOR("NTT Corp.");
MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
"(NILFS)");
MODULE_LICENSE("GPL");
static struct kmem_cache *nilfs_inode_cachep;
struct kmem_cache *nilfs_transaction_cachep;
struct kmem_cache *nilfs_segbuf_cachep;
struct kmem_cache *nilfs_btree_path_cache;
static int nilfs_setup_super(struct super_block *sb, int is_mount);
static int nilfs_remount(struct super_block *sb, int *flags, char *data);
static void nilfs_set_error(struct super_block *sb)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_super_block **sbp;
down_write(&nilfs->ns_sem);
if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
nilfs->ns_mount_state |= NILFS_ERROR_FS;
sbp = nilfs_prepare_super(sb, 0);
if (likely(sbp)) {
sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
if (sbp[1])
sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
}
}
up_write(&nilfs->ns_sem);
}
/**
* nilfs_error() - report failure condition on a filesystem
*
* nilfs_error() sets an ERROR_FS flag on the superblock as well as
* reporting an error message. It should be called when NILFS detects
* incoherences or defects of meta data on disk. As for sustainable
* errors such as a single-shot I/O error, nilfs_warning() or the printk()
* function should be used instead.
*
* The segment constructor must not call this function because it can
* kill itself.
*/
void nilfs_error(struct super_block *sb, const char *function,
const char *fmt, ...)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct va_format vaf;
va_list args;
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
printk(KERN_CRIT "NILFS error (device %s): %s: %pV\n",
sb->s_id, function, &vaf);
va_end(args);
if (!(sb->s_flags & MS_RDONLY)) {
nilfs_set_error(sb);
if (nilfs_test_opt(nilfs, ERRORS_RO)) {
printk(KERN_CRIT "Remounting filesystem read-only\n");
sb->s_flags |= MS_RDONLY;
}
}
if (nilfs_test_opt(nilfs, ERRORS_PANIC))
panic("NILFS (device %s): panic forced after error\n",
sb->s_id);
}
void nilfs_warning(struct super_block *sb, const char *function,
const char *fmt, ...)
{
struct va_format vaf;
va_list args;
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
printk(KERN_WARNING "NILFS warning (device %s): %s: %pV\n",
sb->s_id, function, &vaf);
va_end(args);
}
struct inode *nilfs_alloc_inode(struct super_block *sb)
{
struct nilfs_inode_info *ii;
ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
if (!ii)
return NULL;
ii->i_bh = NULL;
ii->i_state = 0;
ii->i_cno = 0;
ii->vfs_inode.i_version = 1;
nilfs_btnode_cache_init(&ii->i_btnode_cache, sb->s_bdi);
return &ii->vfs_inode;
}
static void nilfs_i_callback(struct rcu_head *head)
{
struct inode *inode = container_of(head, struct inode, i_rcu);
struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
INIT_LIST_HEAD(&inode->i_dentry);
if (mdi) {
kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
kfree(mdi);
}
kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
}
void nilfs_destroy_inode(struct inode *inode)
{
call_rcu(&inode->i_rcu, nilfs_i_callback);
}
static int nilfs_sync_super(struct super_block *sb, int flag)
{
struct the_nilfs *nilfs = sb->s_fs_info;
int err;
retry:
set_buffer_dirty(nilfs->ns_sbh[0]);
if (nilfs_test_opt(nilfs, BARRIER)) {
err = __sync_dirty_buffer(nilfs->ns_sbh[0],
WRITE_SYNC | WRITE_FLUSH_FUA);
} else {
err = sync_dirty_buffer(nilfs->ns_sbh[0]);
}
if (unlikely(err)) {
printk(KERN_ERR
"NILFS: unable to write superblock (err=%d)\n", err);
if (err == -EIO && nilfs->ns_sbh[1]) {
/*
* sbp[0] points to newer log than sbp[1],
* so copy sbp[0] to sbp[1] to take over sbp[0].
*/
memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
nilfs->ns_sbsize);
nilfs_fall_back_super_block(nilfs);
goto retry;
}
} else {
struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
nilfs->ns_sbwcount++;
/*
* The latest segment becomes trailable from the position
* written in superblock.
*/
clear_nilfs_discontinued(nilfs);
/* update GC protection for recent segments */
if (nilfs->ns_sbh[1]) {
if (flag == NILFS_SB_COMMIT_ALL) {
set_buffer_dirty(nilfs->ns_sbh[1]);
if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
goto out;
}
if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
sbp = nilfs->ns_sbp[1];
}
spin_lock(&nilfs->ns_last_segment_lock);
nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
spin_unlock(&nilfs->ns_last_segment_lock);
}
out:
return err;
}
void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
struct the_nilfs *nilfs)
{
sector_t nfreeblocks;
/* nilfs->ns_sem must be locked by the caller. */
nilfs_count_free_blocks(nilfs, &nfreeblocks);
sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
spin_lock(&nilfs->ns_last_segment_lock);
sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
spin_unlock(&nilfs->ns_last_segment_lock);
}
struct nilfs_super_block **nilfs_prepare_super(struct super_block *sb,
int flip)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_super_block **sbp = nilfs->ns_sbp;
/* nilfs->ns_sem must be locked by the caller. */
if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
if (sbp[1] &&
sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
} else {
printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
sb->s_id);
return NULL;
}
} else if (sbp[1] &&
sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
}
if (flip && sbp[1])
nilfs_swap_super_block(nilfs);
return sbp;
}
int nilfs_commit_super(struct super_block *sb, int flag)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_super_block **sbp = nilfs->ns_sbp;
time_t t;
/* nilfs->ns_sem must be locked by the caller. */
t = get_seconds();
nilfs->ns_sbwtime = t;
sbp[0]->s_wtime = cpu_to_le64(t);
sbp[0]->s_sum = 0;
sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
(unsigned char *)sbp[0],
nilfs->ns_sbsize));
if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
sbp[1]->s_wtime = sbp[0]->s_wtime;
sbp[1]->s_sum = 0;
sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
(unsigned char *)sbp[1],
nilfs->ns_sbsize));
}
clear_nilfs_sb_dirty(nilfs);
return nilfs_sync_super(sb, flag);
}
/**
* nilfs_cleanup_super() - write filesystem state for cleanup
* @sb: super block instance to be unmounted or degraded to read-only
*
* This function restores state flags in the on-disk super block.
* This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
* filesystem was not clean previously.
*/
int nilfs_cleanup_super(struct super_block *sb)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_super_block **sbp;
int flag = NILFS_SB_COMMIT;
int ret = -EIO;
sbp = nilfs_prepare_super(sb, 0);
if (sbp) {
sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
nilfs_set_log_cursor(sbp[0], nilfs);
if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
/*
* make the "clean" flag also to the opposite
* super block if both super blocks point to
* the same checkpoint.
*/
sbp[1]->s_state = sbp[0]->s_state;
flag = NILFS_SB_COMMIT_ALL;
}
ret = nilfs_commit_super(sb, flag);
}
return ret;
}
static void nilfs_put_super(struct super_block *sb)
{
struct the_nilfs *nilfs = sb->s_fs_info;
nilfs_detach_log_writer(sb);
if (!(sb->s_flags & MS_RDONLY)) {
down_write(&nilfs->ns_sem);
nilfs_cleanup_super(sb);
up_write(&nilfs->ns_sem);
}
iput(nilfs->ns_sufile);
iput(nilfs->ns_cpfile);
iput(nilfs->ns_dat);
destroy_nilfs(nilfs);
sb->s_fs_info = NULL;
}
static int nilfs_sync_fs(struct super_block *sb, int wait)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_super_block **sbp;
int err = 0;
/* This function is called when super block should be written back */
if (wait)
err = nilfs_construct_segment(sb);
down_write(&nilfs->ns_sem);
if (nilfs_sb_dirty(nilfs)) {
sbp = nilfs_prepare_super(sb, nilfs_sb_will_flip(nilfs));
if (likely(sbp)) {
nilfs_set_log_cursor(sbp[0], nilfs);
nilfs_commit_super(sb, NILFS_SB_COMMIT);
}
}
up_write(&nilfs->ns_sem);
return err;
}
int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
struct nilfs_root **rootp)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_root *root;
struct nilfs_checkpoint *raw_cp;
struct buffer_head *bh_cp;
int err = -ENOMEM;
root = nilfs_find_or_create_root(
nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
if (!root)
return err;
if (root->ifile)
goto reuse; /* already attached checkpoint */
down_read(&nilfs->ns_segctor_sem);
err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
&bh_cp);
up_read(&nilfs->ns_segctor_sem);
if (unlikely(err)) {
if (err == -ENOENT || err == -EINVAL) {
printk(KERN_ERR
"NILFS: Invalid checkpoint "
"(checkpoint number=%llu)\n",
(unsigned long long)cno);
err = -EINVAL;
}
goto failed;
}
err = nilfs_ifile_read(sb, root, nilfs->ns_inode_size,
&raw_cp->cp_ifile_inode, &root->ifile);
if (err)
goto failed_bh;
atomic_set(&root->inodes_count, le64_to_cpu(raw_cp->cp_inodes_count));
atomic_set(&root->blocks_count, le64_to_cpu(raw_cp->cp_blocks_count));
nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
reuse:
*rootp = root;
return 0;
failed_bh:
nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
failed:
nilfs_put_root(root);
return err;
}
static int nilfs_freeze(struct super_block *sb)
{
struct the_nilfs *nilfs = sb->s_fs_info;
int err;
if (sb->s_flags & MS_RDONLY)
return 0;
/* Mark super block clean */
down_write(&nilfs->ns_sem);
err = nilfs_cleanup_super(sb);
up_write(&nilfs->ns_sem);
return err;
}
static int nilfs_unfreeze(struct super_block *sb)
{
struct the_nilfs *nilfs = sb->s_fs_info;
if (sb->s_flags & MS_RDONLY)
return 0;
down_write(&nilfs->ns_sem);
nilfs_setup_super(sb, false);
up_write(&nilfs->ns_sem);
return 0;
}
static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct super_block *sb = dentry->d_sb;
struct nilfs_root *root = NILFS_I(dentry->d_inode)->i_root;
struct the_nilfs *nilfs = root->nilfs;
u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
unsigned long long blocks;
unsigned long overhead;
unsigned long nrsvblocks;
sector_t nfreeblocks;
int err;
/*
* Compute all of the segment blocks
*
* The blocks before first segment and after last segment
* are excluded.
*/
blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
- nilfs->ns_first_data_block;
nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
/*
* Compute the overhead
*
* When distributing meta data blocks outside segment structure,
* We must count them as the overhead.
*/
overhead = 0;
err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
if (unlikely(err))
return err;
buf->f_type = NILFS_SUPER_MAGIC;
buf->f_bsize = sb->s_blocksize;
buf->f_blocks = blocks - overhead;
buf->f_bfree = nfreeblocks;
buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
(buf->f_bfree - nrsvblocks) : 0;
buf->f_files = atomic_read(&root->inodes_count);
buf->f_ffree = 0; /* nilfs_count_free_inodes(sb); */
buf->f_namelen = NILFS_NAME_LEN;
buf->f_fsid.val[0] = (u32)id;
buf->f_fsid.val[1] = (u32)(id >> 32);
return 0;
}
static int nilfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
{
struct super_block *sb = vfs->mnt_sb;
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_root *root = NILFS_I(vfs->mnt_root->d_inode)->i_root;
if (!nilfs_test_opt(nilfs, BARRIER))
seq_puts(seq, ",nobarrier");
if (root->cno != NILFS_CPTREE_CURRENT_CNO)
seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
if (nilfs_test_opt(nilfs, ERRORS_PANIC))
seq_puts(seq, ",errors=panic");
if (nilfs_test_opt(nilfs, ERRORS_CONT))
seq_puts(seq, ",errors=continue");
if (nilfs_test_opt(nilfs, STRICT_ORDER))
seq_puts(seq, ",order=strict");
if (nilfs_test_opt(nilfs, NORECOVERY))
seq_puts(seq, ",norecovery");
if (nilfs_test_opt(nilfs, DISCARD))
seq_puts(seq, ",discard");
return 0;
}
static const struct super_operations nilfs_sops = {
.alloc_inode = nilfs_alloc_inode,
.destroy_inode = nilfs_destroy_inode,
.dirty_inode = nilfs_dirty_inode,
/* .write_inode = nilfs_write_inode, */
/* .put_inode = nilfs_put_inode, */
/* .drop_inode = nilfs_drop_inode, */
.evict_inode = nilfs_evict_inode,
.put_super = nilfs_put_super,
/* .write_super = nilfs_write_super, */
.sync_fs = nilfs_sync_fs,
.freeze_fs = nilfs_freeze,
.unfreeze_fs = nilfs_unfreeze,
/* .write_super_lockfs */
/* .unlockfs */
.statfs = nilfs_statfs,
.remount_fs = nilfs_remount,
/* .umount_begin */
.show_options = nilfs_show_options
};
enum {
Opt_err_cont, Opt_err_panic, Opt_err_ro,
Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
Opt_discard, Opt_nodiscard, Opt_err,
};
static match_table_t tokens = {
{Opt_err_cont, "errors=continue"},
{Opt_err_panic, "errors=panic"},
{Opt_err_ro, "errors=remount-ro"},
{Opt_barrier, "barrier"},
{Opt_nobarrier, "nobarrier"},
{Opt_snapshot, "cp=%u"},
{Opt_order, "order=%s"},
{Opt_norecovery, "norecovery"},
{Opt_discard, "discard"},
{Opt_nodiscard, "nodiscard"},
{Opt_err, NULL}
};
static int parse_options(char *options, struct super_block *sb, int is_remount)
{
struct the_nilfs *nilfs = sb->s_fs_info;
char *p;
substring_t args[MAX_OPT_ARGS];
if (!options)
return 1;
while ((p = strsep(&options, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_barrier:
nilfs_set_opt(nilfs, BARRIER);
break;
case Opt_nobarrier:
nilfs_clear_opt(nilfs, BARRIER);
break;
case Opt_order:
if (strcmp(args[0].from, "relaxed") == 0)
/* Ordered data semantics */
nilfs_clear_opt(nilfs, STRICT_ORDER);
else if (strcmp(args[0].from, "strict") == 0)
/* Strict in-order semantics */
nilfs_set_opt(nilfs, STRICT_ORDER);
else
return 0;
break;
case Opt_err_panic:
nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_PANIC);
break;
case Opt_err_ro:
nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_RO);
break;
case Opt_err_cont:
nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_CONT);
break;
case Opt_snapshot:
if (is_remount) {
printk(KERN_ERR
"NILFS: \"%s\" option is invalid "
"for remount.\n", p);
return 0;
}
break;
case Opt_norecovery:
nilfs_set_opt(nilfs, NORECOVERY);
break;
case Opt_discard:
nilfs_set_opt(nilfs, DISCARD);
break;
case Opt_nodiscard:
nilfs_clear_opt(nilfs, DISCARD);
break;
default:
printk(KERN_ERR
"NILFS: Unrecognized mount option \"%s\"\n", p);
return 0;
}
}
return 1;
}
static inline void
nilfs_set_default_options(struct super_block *sb,
struct nilfs_super_block *sbp)
{
struct the_nilfs *nilfs = sb->s_fs_info;
nilfs->ns_mount_opt =
NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
}
static int nilfs_setup_super(struct super_block *sb, int is_mount)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_super_block **sbp;
int max_mnt_count;
int mnt_count;
/* nilfs->ns_sem must be locked by the caller. */
sbp = nilfs_prepare_super(sb, 0);
if (!sbp)
return -EIO;
if (!is_mount)
goto skip_mount_setup;
max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
printk(KERN_WARNING
"NILFS warning: mounting fs with errors\n");
#if 0
} else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
printk(KERN_WARNING
"NILFS warning: maximal mount count reached\n");
#endif
}
if (!max_mnt_count)
sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
sbp[0]->s_mtime = cpu_to_le64(get_seconds());
skip_mount_setup:
sbp[0]->s_state =
cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
/* synchronize sbp[1] with sbp[0] */
if (sbp[1])
memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
return nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
}
struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
u64 pos, int blocksize,
struct buffer_head **pbh)
{
unsigned long long sb_index = pos;
unsigned long offset;
offset = do_div(sb_index, blocksize);
*pbh = sb_bread(sb, sb_index);
if (!*pbh)
return NULL;
return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
}
int nilfs_store_magic_and_option(struct super_block *sb,
struct nilfs_super_block *sbp,
char *data)
{
struct the_nilfs *nilfs = sb->s_fs_info;
sb->s_magic = le16_to_cpu(sbp->s_magic);
/* FS independent flags */
#ifdef NILFS_ATIME_DISABLE
sb->s_flags |= MS_NOATIME;
#endif
nilfs_set_default_options(sb, sbp);
nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
return !parse_options(data, sb, 0) ? -EINVAL : 0 ;
}
int nilfs_check_feature_compatibility(struct super_block *sb,
struct nilfs_super_block *sbp)
{
__u64 features;
features = le64_to_cpu(sbp->s_feature_incompat) &
~NILFS_FEATURE_INCOMPAT_SUPP;
if (features) {
printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
"optional features (%llx)\n",
(unsigned long long)features);
return -EINVAL;
}
features = le64_to_cpu(sbp->s_feature_compat_ro) &
~NILFS_FEATURE_COMPAT_RO_SUPP;
if (!(sb->s_flags & MS_RDONLY) && features) {
printk(KERN_ERR "NILFS: couldn't mount RDWR because of "
"unsupported optional features (%llx)\n",
(unsigned long long)features);
return -EINVAL;
}
return 0;
}
static int nilfs_get_root_dentry(struct super_block *sb,
struct nilfs_root *root,
struct dentry **root_dentry)
{
struct inode *inode;
struct dentry *dentry;
int ret = 0;
inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
if (IS_ERR(inode)) {
printk(KERN_ERR "NILFS: get root inode failed\n");
ret = PTR_ERR(inode);
goto out;
}
if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
iput(inode);
printk(KERN_ERR "NILFS: corrupt root inode.\n");
ret = -EINVAL;
goto out;
}
if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
dentry = d_find_alias(inode);
if (!dentry) {
dentry = d_alloc_root(inode);
if (!dentry) {
iput(inode);
ret = -ENOMEM;
goto failed_dentry;
}
} else {
iput(inode);
}
} else {
dentry = d_obtain_alias(inode);
if (IS_ERR(dentry)) {
ret = PTR_ERR(dentry);
goto failed_dentry;
}
}
*root_dentry = dentry;
out:
return ret;
failed_dentry:
printk(KERN_ERR "NILFS: get root dentry failed\n");
goto out;
}
static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
struct dentry **root_dentry)
{
struct the_nilfs *nilfs = s->s_fs_info;
struct nilfs_root *root;
int ret;
down_read(&nilfs->ns_segctor_sem);
ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
up_read(&nilfs->ns_segctor_sem);
if (ret < 0) {
ret = (ret == -ENOENT) ? -EINVAL : ret;
goto out;
} else if (!ret) {
printk(KERN_ERR "NILFS: The specified checkpoint is "
"not a snapshot (checkpoint number=%llu).\n",
(unsigned long long)cno);
ret = -EINVAL;
goto out;
}
ret = nilfs_attach_checkpoint(s, cno, false, &root);
if (ret) {
printk(KERN_ERR "NILFS: error loading snapshot "
"(checkpoint number=%llu).\n",
(unsigned long long)cno);
goto out;
}
ret = nilfs_get_root_dentry(s, root, root_dentry);
nilfs_put_root(root);
out:
return ret;
}
static int nilfs_tree_was_touched(struct dentry *root_dentry)
{
return root_dentry->d_count > 1;
}
/**
* nilfs_try_to_shrink_tree() - try to shrink dentries of a checkpoint
* @root_dentry: root dentry of the tree to be shrunk
*
* This function returns true if the tree was in-use.
*/
static int nilfs_try_to_shrink_tree(struct dentry *root_dentry)
{
if (have_submounts(root_dentry))
return true;
shrink_dcache_parent(root_dentry);
return nilfs_tree_was_touched(root_dentry);
}
int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_root *root;
struct inode *inode;
struct dentry *dentry;
int ret;
if (cno < 0 || cno > nilfs->ns_cno)
return false;
if (cno >= nilfs_last_cno(nilfs))
return true; /* protect recent checkpoints */
ret = false;
root = nilfs_lookup_root(nilfs, cno);
if (root) {
inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
if (inode) {
dentry = d_find_alias(inode);
if (dentry) {
if (nilfs_tree_was_touched(dentry))
ret = nilfs_try_to_shrink_tree(dentry);
dput(dentry);
}
iput(inode);
}
nilfs_put_root(root);
}
return ret;
}
/**
* nilfs_fill_super() - initialize a super block instance
* @sb: super_block
* @data: mount options
* @silent: silent mode flag
*
* This function is called exclusively by nilfs->ns_mount_mutex.
* So, the recovery process is protected from other simultaneous mounts.
*/
static int
nilfs_fill_super(struct super_block *sb, void *data, int silent)
{
struct the_nilfs *nilfs;
struct nilfs_root *fsroot;
struct backing_dev_info *bdi;
__u64 cno;
int err;
nilfs = alloc_nilfs(sb->s_bdev);
if (!nilfs)
return -ENOMEM;
sb->s_fs_info = nilfs;
err = init_nilfs(nilfs, sb, (char *)data);
if (err)
goto failed_nilfs;
sb->s_op = &nilfs_sops;
sb->s_export_op = &nilfs_export_ops;
sb->s_root = NULL;
sb->s_time_gran = 1;
bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
sb->s_bdi = bdi ? : &default_backing_dev_info;
err = load_nilfs(nilfs, sb);
if (err)
goto failed_nilfs;
cno = nilfs_last_cno(nilfs);
err = nilfs_attach_checkpoint(sb, cno, true, &fsroot);
if (err) {
printk(KERN_ERR "NILFS: error loading last checkpoint "
"(checkpoint number=%llu).\n", (unsigned long long)cno);
goto failed_unload;
}
if (!(sb->s_flags & MS_RDONLY)) {
err = nilfs_attach_log_writer(sb, fsroot);
if (err)
goto failed_checkpoint;
}
err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
if (err)
goto failed_segctor;
nilfs_put_root(fsroot);
if (!(sb->s_flags & MS_RDONLY)) {
down_write(&nilfs->ns_sem);
nilfs_setup_super(sb, true);
up_write(&nilfs->ns_sem);
}
return 0;
failed_segctor:
nilfs_detach_log_writer(sb);
failed_checkpoint:
nilfs_put_root(fsroot);
failed_unload:
iput(nilfs->ns_sufile);
iput(nilfs->ns_cpfile);
iput(nilfs->ns_dat);
failed_nilfs:
destroy_nilfs(nilfs);
return err;
}
static int nilfs_remount(struct super_block *sb, int *flags, char *data)
{
struct the_nilfs *nilfs = sb->s_fs_info;
unsigned long old_sb_flags;
unsigned long old_mount_opt;
int err;
old_sb_flags = sb->s_flags;
old_mount_opt = nilfs->ns_mount_opt;
if (!parse_options(data, sb, 1)) {
err = -EINVAL;
goto restore_opts;
}
sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
err = -EINVAL;
if (!nilfs_valid_fs(nilfs)) {
printk(KERN_WARNING "NILFS (device %s): couldn't "
"remount because the filesystem is in an "
"incomplete recovery state.\n", sb->s_id);
goto restore_opts;
}
if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
goto out;
if (*flags & MS_RDONLY) {
/* Shutting down log writer */
nilfs_detach_log_writer(sb);
sb->s_flags |= MS_RDONLY;
/*
* Remounting a valid RW partition RDONLY, so set
* the RDONLY flag and then mark the partition as valid again.
*/
down_write(&nilfs->ns_sem);
nilfs_cleanup_super(sb);
up_write(&nilfs->ns_sem);
} else {
__u64 features;
struct nilfs_root *root;
/*
* Mounting a RDONLY partition read-write, so reread and
* store the current valid flag. (It may have been changed
* by fsck since we originally mounted the partition.)
*/
down_read(&nilfs->ns_sem);
features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
~NILFS_FEATURE_COMPAT_RO_SUPP;
up_read(&nilfs->ns_sem);
if (features) {
printk(KERN_WARNING "NILFS (device %s): couldn't "
"remount RDWR because of unsupported optional "
"features (%llx)\n",
sb->s_id, (unsigned long long)features);
err = -EROFS;
goto restore_opts;
}
sb->s_flags &= ~MS_RDONLY;
root = NILFS_I(sb->s_root->d_inode)->i_root;
err = nilfs_attach_log_writer(sb, root);
if (err)
goto restore_opts;
down_write(&nilfs->ns_sem);
nilfs_setup_super(sb, true);
up_write(&nilfs->ns_sem);
}
out:
return 0;
restore_opts:
sb->s_flags = old_sb_flags;
nilfs->ns_mount_opt = old_mount_opt;
return err;
}
struct nilfs_super_data {
struct block_device *bdev;
__u64 cno;
int flags;
};
/**
* nilfs_identify - pre-read mount options needed to identify mount instance
* @data: mount options
* @sd: nilfs_super_data
*/
static int nilfs_identify(char *data, struct nilfs_super_data *sd)
{
char *p, *options = data;
substring_t args[MAX_OPT_ARGS];
int token;
int ret = 0;
do {
p = strsep(&options, ",");
if (p != NULL && *p) {
token = match_token(p, tokens, args);
if (token == Opt_snapshot) {
if (!(sd->flags & MS_RDONLY)) {
ret++;
} else {
sd->cno = simple_strtoull(args[0].from,
NULL, 0);
/*
* No need to see the end pointer;
* match_token() has done syntax
* checking.
*/
if (sd->cno == 0)
ret++;
}
}
if (ret)
printk(KERN_ERR
"NILFS: invalid mount option: %s\n", p);
}
if (!options)
break;
BUG_ON(options == data);
*(options - 1) = ',';
} while (!ret);
return ret;
}
static int nilfs_set_bdev_super(struct super_block *s, void *data)
{
s->s_bdev = data;
s->s_dev = s->s_bdev->bd_dev;
return 0;
}
static int nilfs_test_bdev_super(struct super_block *s, void *data)
{
return (void *)s->s_bdev == data;
}
static struct dentry *
nilfs_mount(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data)
{
struct nilfs_super_data sd;
struct super_block *s;
fmode_t mode = FMODE_READ | FMODE_EXCL;
struct dentry *root_dentry;
int err, s_new = false;
if (!(flags & MS_RDONLY))
mode |= FMODE_WRITE;
sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
if (IS_ERR(sd.bdev))
return ERR_CAST(sd.bdev);
sd.cno = 0;
sd.flags = flags;
if (nilfs_identify((char *)data, &sd)) {
err = -EINVAL;
goto failed;
}
/*
* once the super is inserted into the list by sget, s_umount
* will protect the lockfs code from trying to start a snapshot
* while we are mounting
*/
mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
if (sd.bdev->bd_fsfreeze_count > 0) {
mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
err = -EBUSY;
goto failed;
}
s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, sd.bdev);
mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
if (IS_ERR(s)) {
err = PTR_ERR(s);
goto failed;
}
if (!s->s_root) {
char b[BDEVNAME_SIZE];
s_new = true;
/* New superblock instance created */
s->s_flags = flags;
s->s_mode = mode;
strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
sb_set_blocksize(s, block_size(sd.bdev));
err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
if (err)
goto failed_super;
s->s_flags |= MS_ACTIVE;
} else if (!sd.cno) {
int busy = false;
if (nilfs_tree_was_touched(s->s_root)) {
busy = nilfs_try_to_shrink_tree(s->s_root);
if (busy && (flags ^ s->s_flags) & MS_RDONLY) {
printk(KERN_ERR "NILFS: the device already "
"has a %s mount.\n",
(s->s_flags & MS_RDONLY) ?
"read-only" : "read/write");
err = -EBUSY;
goto failed_super;
}
}
if (!busy) {
/*
* Try remount to setup mount states if the current
* tree is not mounted and only snapshots use this sb.
*/
err = nilfs_remount(s, &flags, data);
if (err)
goto failed_super;
}
}
if (sd.cno) {
err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
if (err)
goto failed_super;
} else {
root_dentry = dget(s->s_root);
}
if (!s_new)
blkdev_put(sd.bdev, mode);
return root_dentry;
failed_super:
deactivate_locked_super(s);
failed:
if (!s_new)
blkdev_put(sd.bdev, mode);
return ERR_PTR(err);
}
struct file_system_type nilfs_fs_type = {
.owner = THIS_MODULE,
.name = "nilfs2",
.mount = nilfs_mount,
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
static void nilfs_inode_init_once(void *obj)
{
struct nilfs_inode_info *ii = obj;
INIT_LIST_HEAD(&ii->i_dirty);
#ifdef CONFIG_NILFS_XATTR
init_rwsem(&ii->xattr_sem);
#endif
address_space_init_once(&ii->i_btnode_cache);
ii->i_bmap = &ii->i_bmap_data;
inode_init_once(&ii->vfs_inode);
}
static void nilfs_segbuf_init_once(void *obj)
{
memset(obj, 0, sizeof(struct nilfs_segment_buffer));
}
static void nilfs_destroy_cachep(void)
{
if (nilfs_inode_cachep)
kmem_cache_destroy(nilfs_inode_cachep);
if (nilfs_transaction_cachep)
kmem_cache_destroy(nilfs_transaction_cachep);
if (nilfs_segbuf_cachep)
kmem_cache_destroy(nilfs_segbuf_cachep);
if (nilfs_btree_path_cache)
kmem_cache_destroy(nilfs_btree_path_cache);
}
static int __init nilfs_init_cachep(void)
{
nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
sizeof(struct nilfs_inode_info), 0,
SLAB_RECLAIM_ACCOUNT, nilfs_inode_init_once);
if (!nilfs_inode_cachep)
goto fail;
nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
sizeof(struct nilfs_transaction_info), 0,
SLAB_RECLAIM_ACCOUNT, NULL);
if (!nilfs_transaction_cachep)
goto fail;
nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
sizeof(struct nilfs_segment_buffer), 0,
SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
if (!nilfs_segbuf_cachep)
goto fail;
nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
0, 0, NULL);
if (!nilfs_btree_path_cache)
goto fail;
return 0;
fail:
nilfs_destroy_cachep();
return -ENOMEM;
}
static int __init init_nilfs_fs(void)
{
int err;
err = nilfs_init_cachep();
if (err)
goto fail;
err = register_filesystem(&nilfs_fs_type);
if (err)
goto free_cachep;
printk(KERN_INFO "NILFS version 2 loaded\n");
return 0;
free_cachep:
nilfs_destroy_cachep();
fail:
return err;
}
static void __exit exit_nilfs_fs(void)
{
nilfs_destroy_cachep();
unregister_filesystem(&nilfs_fs_type);
}
module_init(init_nilfs_fs)
module_exit(exit_nilfs_fs)