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super.c
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/*
* 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/random.h>
#include <linux/crc32.h>
#include <linux/smp_lock.h>
#include <linux/vfs.h>
#include <linux/writeback.h>
#include <linux/kobject.h>
#include <linux/exportfs.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include "nilfs.h"
#include "mdt.h"
#include "alloc.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 int nilfs_remount(struct super_block *sb, int *flags, char *data);
/**
* 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 nilfs_sb_info *sbi = NILFS_SB(sb);
va_list args;
va_start(args, fmt);
printk(KERN_CRIT "NILFS error (device %s): %s: ", sb->s_id, function);
vprintk(fmt, args);
printk("\n");
va_end(args);
if (!(sb->s_flags & MS_RDONLY)) {
struct the_nilfs *nilfs = sbi->s_nilfs;
if (!nilfs_test_opt(sbi, ERRORS_CONT))
nilfs_detach_segment_constructor(sbi);
down_write(&nilfs->ns_sem);
if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
nilfs->ns_mount_state |= NILFS_ERROR_FS;
nilfs->ns_sbp[0]->s_state |=
cpu_to_le16(NILFS_ERROR_FS);
nilfs_commit_super(sbi, 1);
}
up_write(&nilfs->ns_sem);
if (nilfs_test_opt(sbi, ERRORS_RO)) {
printk(KERN_CRIT "Remounting filesystem read-only\n");
sb->s_flags |= MS_RDONLY;
}
}
if (nilfs_test_opt(sbi, 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, ...)
{
va_list args;
va_start(args, fmt);
printk(KERN_WARNING "NILFS warning (device %s): %s: ",
sb->s_id, function);
vprintk(fmt, args);
printk("\n");
va_end(args);
}
static struct kmem_cache *nilfs_inode_cachep;
struct inode *nilfs_alloc_inode_common(struct the_nilfs *nilfs)
{
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->vfs_inode.i_version = 1;
nilfs_btnode_cache_init(&ii->i_btnode_cache, nilfs->ns_bdi);
return &ii->vfs_inode;
}
struct inode *nilfs_alloc_inode(struct super_block *sb)
{
return nilfs_alloc_inode_common(NILFS_SB(sb)->s_nilfs);
}
void nilfs_destroy_inode(struct inode *inode)
{
kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
}
static void 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
nilfs_btnode_cache_init_once(&ii->i_btnode_cache);
ii->i_bmap = (struct nilfs_bmap *)&ii->i_bmap_union;
inode_init_once(&ii->vfs_inode);
}
static int nilfs_init_inode_cache(void)
{
nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
sizeof(struct nilfs_inode_info),
0, SLAB_RECLAIM_ACCOUNT,
init_once);
return (nilfs_inode_cachep == NULL) ? -ENOMEM : 0;
}
static inline void nilfs_destroy_inode_cache(void)
{
kmem_cache_destroy(nilfs_inode_cachep);
}
static void nilfs_clear_inode(struct inode *inode)
{
struct nilfs_inode_info *ii = NILFS_I(inode);
/*
* Free resources allocated in nilfs_read_inode(), here.
*/
BUG_ON(!list_empty(&ii->i_dirty));
brelse(ii->i_bh);
ii->i_bh = NULL;
if (test_bit(NILFS_I_BMAP, &ii->i_state))
nilfs_bmap_clear(ii->i_bmap);
nilfs_btnode_cache_clear(&ii->i_btnode_cache);
}
static int nilfs_sync_super(struct nilfs_sb_info *sbi, int dupsb)
{
struct the_nilfs *nilfs = sbi->s_nilfs;
int err;
int barrier_done = 0;
if (nilfs_test_opt(sbi, BARRIER)) {
set_buffer_ordered(nilfs->ns_sbh[0]);
barrier_done = 1;
}
retry:
set_buffer_dirty(nilfs->ns_sbh[0]);
err = sync_dirty_buffer(nilfs->ns_sbh[0]);
if (err == -EOPNOTSUPP && barrier_done) {
nilfs_warning(sbi->s_super, __func__,
"barrier-based sync failed. "
"disabling barriers\n");
nilfs_clear_opt(sbi, BARRIER);
barrier_done = 0;
clear_buffer_ordered(nilfs->ns_sbh[0]);
goto retry;
}
if (unlikely(err)) {
printk(KERN_ERR
"NILFS: unable to write superblock (err=%d)\n", err);
if (err == -EIO && nilfs->ns_sbh[1]) {
nilfs_fall_back_super_block(nilfs);
goto retry;
}
} else {
struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
/*
* 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]) {
sbp = NULL;
if (dupsb) {
set_buffer_dirty(nilfs->ns_sbh[1]);
if (!sync_dirty_buffer(nilfs->ns_sbh[1]))
sbp = nilfs->ns_sbp[1];
}
}
if (sbp) {
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);
}
}
return err;
}
int nilfs_commit_super(struct nilfs_sb_info *sbi, int dupsb)
{
struct the_nilfs *nilfs = sbi->s_nilfs;
struct nilfs_super_block **sbp = nilfs->ns_sbp;
sector_t nfreeblocks;
time_t t;
int err;
/* nilfs->sem must be locked by the caller. */
if (sbp[0]->s_magic != NILFS_SUPER_MAGIC) {
if (sbp[1] && sbp[1]->s_magic == NILFS_SUPER_MAGIC)
nilfs_swap_super_block(nilfs);
else {
printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
sbi->s_super->s_id);
return -EIO;
}
}
err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
if (unlikely(err)) {
printk(KERN_ERR "NILFS: failed to count free blocks\n");
return err;
}
spin_lock(&nilfs->ns_last_segment_lock);
sbp[0]->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
sbp[0]->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
sbp[0]->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
spin_unlock(&nilfs->ns_last_segment_lock);
t = get_seconds();
nilfs->ns_sbwtime[0] = t;
sbp[0]->s_free_blocks_count = cpu_to_le64(nfreeblocks);
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 (dupsb && sbp[1]) {
memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
nilfs->ns_sbwtime[1] = t;
}
sbi->s_super->s_dirt = 0;
return nilfs_sync_super(sbi, dupsb);
}
static void nilfs_put_super(struct super_block *sb)
{
struct nilfs_sb_info *sbi = NILFS_SB(sb);
struct the_nilfs *nilfs = sbi->s_nilfs;
lock_kernel();
nilfs_detach_segment_constructor(sbi);
if (!(sb->s_flags & MS_RDONLY)) {
down_write(&nilfs->ns_sem);
nilfs->ns_sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
nilfs_commit_super(sbi, 1);
up_write(&nilfs->ns_sem);
}
down_write(&nilfs->ns_super_sem);
if (nilfs->ns_current == sbi)
nilfs->ns_current = NULL;
up_write(&nilfs->ns_super_sem);
nilfs_detach_checkpoint(sbi);
put_nilfs(sbi->s_nilfs);
sbi->s_super = NULL;
sb->s_fs_info = NULL;
nilfs_put_sbinfo(sbi);
unlock_kernel();
}
static int nilfs_sync_fs(struct super_block *sb, int wait)
{
struct nilfs_sb_info *sbi = NILFS_SB(sb);
struct the_nilfs *nilfs = sbi->s_nilfs;
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 (sb->s_dirt)
nilfs_commit_super(sbi, 1);
up_write(&nilfs->ns_sem);
return err;
}
int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno)
{
struct the_nilfs *nilfs = sbi->s_nilfs;
struct nilfs_checkpoint *raw_cp;
struct buffer_head *bh_cp;
int err;
down_write(&nilfs->ns_super_sem);
list_add(&sbi->s_list, &nilfs->ns_supers);
up_write(&nilfs->ns_super_sem);
sbi->s_ifile = nilfs_mdt_new(nilfs, sbi->s_super, NILFS_IFILE_INO);
if (!sbi->s_ifile)
return -ENOMEM;
err = nilfs_palloc_init_blockgroup(sbi->s_ifile, nilfs->ns_inode_size);
if (unlikely(err))
goto failed;
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_read_inode_common(sbi->s_ifile, &raw_cp->cp_ifile_inode);
if (unlikely(err))
goto failed_bh;
atomic_set(&sbi->s_inodes_count, le64_to_cpu(raw_cp->cp_inodes_count));
atomic_set(&sbi->s_blocks_count, le64_to_cpu(raw_cp->cp_blocks_count));
nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
return 0;
failed_bh:
nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
failed:
nilfs_mdt_destroy(sbi->s_ifile);
sbi->s_ifile = NULL;
down_write(&nilfs->ns_super_sem);
list_del_init(&sbi->s_list);
up_write(&nilfs->ns_super_sem);
return err;
}
void nilfs_detach_checkpoint(struct nilfs_sb_info *sbi)
{
struct the_nilfs *nilfs = sbi->s_nilfs;
nilfs_mdt_clear(sbi->s_ifile);
nilfs_mdt_destroy(sbi->s_ifile);
sbi->s_ifile = NULL;
down_write(&nilfs->ns_super_sem);
list_del_init(&sbi->s_list);
up_write(&nilfs->ns_super_sem);
}
static int nilfs_mark_recovery_complete(struct nilfs_sb_info *sbi)
{
struct the_nilfs *nilfs = sbi->s_nilfs;
int err = 0;
down_write(&nilfs->ns_sem);
if (!(nilfs->ns_mount_state & NILFS_VALID_FS)) {
nilfs->ns_mount_state |= NILFS_VALID_FS;
err = nilfs_commit_super(sbi, 1);
if (likely(!err))
printk(KERN_INFO "NILFS: recovery complete.\n");
}
up_write(&nilfs->ns_sem);
return err;
}
static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct super_block *sb = dentry->d_sb;
struct nilfs_sb_info *sbi = NILFS_SB(sb);
struct the_nilfs *nilfs = sbi->s_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 semgent 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(&sbi->s_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 nilfs_sb_info *sbi = NILFS_SB(sb);
if (!nilfs_test_opt(sbi, BARRIER))
seq_printf(seq, ",barrier=off");
if (nilfs_test_opt(sbi, SNAPSHOT))
seq_printf(seq, ",cp=%llu",
(unsigned long long int)sbi->s_snapshot_cno);
if (nilfs_test_opt(sbi, ERRORS_RO))
seq_printf(seq, ",errors=remount-ro");
if (nilfs_test_opt(sbi, ERRORS_PANIC))
seq_printf(seq, ",errors=panic");
if (nilfs_test_opt(sbi, STRICT_ORDER))
seq_printf(seq, ",order=strict");
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, */
.delete_inode = nilfs_delete_inode,
.put_super = nilfs_put_super,
/* .write_super = nilfs_write_super, */
.sync_fs = nilfs_sync_fs,
/* .write_super_lockfs */
/* .unlockfs */
.statfs = nilfs_statfs,
.remount_fs = nilfs_remount,
.clear_inode = nilfs_clear_inode,
/* .umount_begin */
.show_options = nilfs_show_options
};
static struct inode *
nilfs_nfs_get_inode(struct super_block *sb, u64 ino, u32 generation)
{
struct inode *inode;
if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO &&
ino != NILFS_SKETCH_INO)
return ERR_PTR(-ESTALE);
inode = nilfs_iget(sb, ino);
if (IS_ERR(inode))
return ERR_CAST(inode);
if (generation && inode->i_generation != generation) {
iput(inode);
return ERR_PTR(-ESTALE);
}
return inode;
}
static struct dentry *
nilfs_fh_to_dentry(struct super_block *sb, struct fid *fid, int fh_len,
int fh_type)
{
return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
nilfs_nfs_get_inode);
}
static struct dentry *
nilfs_fh_to_parent(struct super_block *sb, struct fid *fid, int fh_len,
int fh_type)
{
return generic_fh_to_parent(sb, fid, fh_len, fh_type,
nilfs_nfs_get_inode);
}
static const struct export_operations nilfs_export_ops = {
.fh_to_dentry = nilfs_fh_to_dentry,
.fh_to_parent = nilfs_fh_to_parent,
.get_parent = nilfs_get_parent,
};
enum {
Opt_err_cont, Opt_err_panic, Opt_err_ro,
Opt_barrier, Opt_snapshot, Opt_order,
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=%s"},
{Opt_snapshot, "cp=%u"},
{Opt_order, "order=%s"},
{Opt_err, NULL}
};
static int match_bool(substring_t *s, int *result)
{
int len = s->to - s->from;
if (strncmp(s->from, "on", len) == 0)
*result = 1;
else if (strncmp(s->from, "off", len) == 0)
*result = 0;
else
return 1;
return 0;
}
static int parse_options(char *options, struct super_block *sb)
{
struct nilfs_sb_info *sbi = NILFS_SB(sb);
char *p;
substring_t args[MAX_OPT_ARGS];
int option;
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:
if (match_bool(&args[0], &option))
return 0;
if (option)
nilfs_set_opt(sbi, BARRIER);
else
nilfs_clear_opt(sbi, BARRIER);
break;
case Opt_order:
if (strcmp(args[0].from, "relaxed") == 0)
/* Ordered data semantics */
nilfs_clear_opt(sbi, STRICT_ORDER);
else if (strcmp(args[0].from, "strict") == 0)
/* Strict in-order semantics */
nilfs_set_opt(sbi, STRICT_ORDER);
else
return 0;
break;
case Opt_err_panic:
nilfs_write_opt(sbi, ERROR_MODE, ERRORS_PANIC);
break;
case Opt_err_ro:
nilfs_write_opt(sbi, ERROR_MODE, ERRORS_RO);
break;
case Opt_err_cont:
nilfs_write_opt(sbi, ERROR_MODE, ERRORS_CONT);
break;
case Opt_snapshot:
if (match_int(&args[0], &option) || option <= 0)
return 0;
if (!(sb->s_flags & MS_RDONLY))
return 0;
sbi->s_snapshot_cno = option;
nilfs_set_opt(sbi, SNAPSHOT);
break;
default:
printk(KERN_ERR
"NILFS: Unrecognized mount option \"%s\"\n", p);
return 0;
}
}
return 1;
}
static inline void
nilfs_set_default_options(struct nilfs_sb_info *sbi,
struct nilfs_super_block *sbp)
{
sbi->s_mount_opt =
NILFS_MOUNT_ERRORS_CONT | NILFS_MOUNT_BARRIER;
}
static int nilfs_setup_super(struct nilfs_sb_info *sbi)
{
struct the_nilfs *nilfs = sbi->s_nilfs;
struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
int max_mnt_count = le16_to_cpu(sbp->s_max_mnt_count);
int mnt_count = le16_to_cpu(sbp->s_mnt_count);
/* nilfs->sem must be locked by the caller. */
if (!(nilfs->ns_mount_state & NILFS_VALID_FS)) {
printk(KERN_WARNING "NILFS warning: mounting unchecked fs\n");
} else 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->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
sbp->s_mnt_count = cpu_to_le16(mnt_count + 1);
sbp->s_state = cpu_to_le16(le16_to_cpu(sbp->s_state) & ~NILFS_VALID_FS);
sbp->s_mtime = cpu_to_le64(get_seconds());
return nilfs_commit_super(sbi, 1);
}
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 nilfs_sb_info *sbi = NILFS_SB(sb);
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(sbi, sbp);
sbi->s_resuid = le16_to_cpu(sbp->s_def_resuid);
sbi->s_resgid = le16_to_cpu(sbp->s_def_resgid);
sbi->s_interval = le32_to_cpu(sbp->s_c_interval);
sbi->s_watermark = le32_to_cpu(sbp->s_c_block_max);
return !parse_options(data, sb) ? -EINVAL : 0 ;
}
/**
* nilfs_fill_super() - initialize a super block instance
* @sb: super_block
* @data: mount options
* @silent: silent mode flag
* @nilfs: the_nilfs struct
*
* 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_sb_info *sbi;
struct inode *root;
__u64 cno;
int err;
sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
sb->s_fs_info = sbi;
get_nilfs(nilfs);
sbi->s_nilfs = nilfs;
sbi->s_super = sb;
atomic_set(&sbi->s_count, 1);
err = init_nilfs(nilfs, sbi, (char *)data);
if (err)
goto failed_sbi;
spin_lock_init(&sbi->s_inode_lock);
INIT_LIST_HEAD(&sbi->s_dirty_files);
INIT_LIST_HEAD(&sbi->s_list);
/*
* Following initialization is overlapped because
* nilfs_sb_info structure has been cleared at the beginning.
* But we reserve them to keep our interest and make ready
* for the future change.
*/
get_random_bytes(&sbi->s_next_generation,
sizeof(sbi->s_next_generation));
spin_lock_init(&sbi->s_next_gen_lock);
sb->s_op = &nilfs_sops;
sb->s_export_op = &nilfs_export_ops;
sb->s_root = NULL;
sb->s_time_gran = 1;
if (!nilfs_loaded(nilfs)) {
err = load_nilfs(nilfs, sbi);
if (err)
goto failed_sbi;
}
cno = nilfs_last_cno(nilfs);
if (sb->s_flags & MS_RDONLY) {
if (nilfs_test_opt(sbi, SNAPSHOT)) {
down_read(&nilfs->ns_segctor_sem);
err = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile,
sbi->s_snapshot_cno);
up_read(&nilfs->ns_segctor_sem);
if (err < 0) {
if (err == -ENOENT)
err = -EINVAL;
goto failed_sbi;
}
if (!err) {
printk(KERN_ERR
"NILFS: The specified checkpoint is "
"not a snapshot "
"(checkpoint number=%llu).\n",
(unsigned long long)sbi->s_snapshot_cno);
err = -EINVAL;
goto failed_sbi;
}
cno = sbi->s_snapshot_cno;
} else
/* Read-only mount */
sbi->s_snapshot_cno = cno;
}
err = nilfs_attach_checkpoint(sbi, cno);
if (err) {
printk(KERN_ERR "NILFS: error loading a checkpoint"
" (checkpoint number=%llu).\n", (unsigned long long)cno);
goto failed_sbi;
}
if (!(sb->s_flags & MS_RDONLY)) {
err = nilfs_attach_segment_constructor(sbi);
if (err)
goto failed_checkpoint;
}
root = nilfs_iget(sb, NILFS_ROOT_INO);
if (IS_ERR(root)) {
printk(KERN_ERR "NILFS: get root inode failed\n");
err = PTR_ERR(root);
goto failed_segctor;
}
if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
iput(root);
printk(KERN_ERR "NILFS: corrupt root inode.\n");
err = -EINVAL;
goto failed_segctor;
}
sb->s_root = d_alloc_root(root);
if (!sb->s_root) {
iput(root);
printk(KERN_ERR "NILFS: get root dentry failed\n");
err = -ENOMEM;
goto failed_segctor;
}
if (!(sb->s_flags & MS_RDONLY)) {
down_write(&nilfs->ns_sem);
nilfs_setup_super(sbi);
up_write(&nilfs->ns_sem);
}
err = nilfs_mark_recovery_complete(sbi);
if (unlikely(err)) {
printk(KERN_ERR "NILFS: recovery failed.\n");
goto failed_root;
}
down_write(&nilfs->ns_super_sem);
if (!nilfs_test_opt(sbi, SNAPSHOT))
nilfs->ns_current = sbi;
up_write(&nilfs->ns_super_sem);
return 0;
failed_root:
dput(sb->s_root);
sb->s_root = NULL;
failed_segctor:
nilfs_detach_segment_constructor(sbi);
failed_checkpoint:
nilfs_detach_checkpoint(sbi);
failed_sbi:
put_nilfs(nilfs);
sb->s_fs_info = NULL;
nilfs_put_sbinfo(sbi);
return err;
}
static int nilfs_remount(struct super_block *sb, int *flags, char *data)
{
struct nilfs_sb_info *sbi = NILFS_SB(sb);
struct nilfs_super_block *sbp;
struct the_nilfs *nilfs = sbi->s_nilfs;
unsigned long old_sb_flags;
struct nilfs_mount_options old_opts;
int err;
lock_kernel();
down_write(&nilfs->ns_super_sem);
old_sb_flags = sb->s_flags;
old_opts.mount_opt = sbi->s_mount_opt;
old_opts.snapshot_cno = sbi->s_snapshot_cno;
if (!parse_options(data, sb)) {
err = -EINVAL;
goto restore_opts;
}
sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
if ((*flags & MS_RDONLY) &&
sbi->s_snapshot_cno != old_opts.snapshot_cno) {
printk(KERN_WARNING "NILFS (device %s): couldn't "
"remount to a different snapshot. \n",
sb->s_id);
err = -EINVAL;
goto restore_opts;
}
if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
goto out;
if (*flags & MS_RDONLY) {
/* Shutting down the segment constructor */
nilfs_detach_segment_constructor(sbi);
sb->s_flags |= MS_RDONLY;
sbi->s_snapshot_cno = nilfs_last_cno(nilfs);
/* nilfs_set_opt(sbi, SNAPSHOT); */
/*
* Remounting a valid RW partition RDONLY, so set
* the RDONLY flag and then mark the partition as valid again.
*/
down_write(&nilfs->ns_sem);
sbp = nilfs->ns_sbp[0];
if (!(sbp->s_state & le16_to_cpu(NILFS_VALID_FS)) &&
(nilfs->ns_mount_state & NILFS_VALID_FS))
sbp->s_state = cpu_to_le16(nilfs->ns_mount_state);
sbp->s_mtime = cpu_to_le64(get_seconds());
nilfs_commit_super(sbi, 1);
up_write(&nilfs->ns_sem);
} else {
/*
* 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.)
*/
if (nilfs->ns_current && nilfs->ns_current != sbi) {
printk(KERN_WARNING "NILFS (device %s): couldn't "
"remount because an RW-mount exists.\n",
sb->s_id);
err = -EBUSY;
goto restore_opts;
}
if (sbi->s_snapshot_cno != nilfs_last_cno(nilfs)) {
printk(KERN_WARNING "NILFS (device %s): couldn't "
"remount because the current RO-mount is not "
"the latest one.\n",
sb->s_id);
err = -EINVAL;
goto restore_opts;
}
sb->s_flags &= ~MS_RDONLY;
nilfs_clear_opt(sbi, SNAPSHOT);
sbi->s_snapshot_cno = 0;
err = nilfs_attach_segment_constructor(sbi);
if (err)
goto restore_opts;
down_write(&nilfs->ns_sem);
nilfs_setup_super(sbi);
up_write(&nilfs->ns_sem);
nilfs->ns_current = sbi;
}
out:
up_write(&nilfs->ns_super_sem);
unlock_kernel();
return 0;
restore_opts:
sb->s_flags = old_sb_flags;
sbi->s_mount_opt = old_opts.mount_opt;
sbi->s_snapshot_cno = old_opts.snapshot_cno;
up_write(&nilfs->ns_super_sem);
unlock_kernel();
return err;
}
struct nilfs_super_data {
struct block_device *bdev;
struct nilfs_sb_info *sbi;
__u64 cno;
int flags;
};
/**
* nilfs_identify - pre-read mount options needed to identify mount instance
* @data: mount options
* @sd: nilfs_super_data
*/