Re: [PATCH 04/16 v2] f2fs: add super block operations

[Vyacheslav Dubeyko]

On Oct 23, 2012, at 6:27 AM, Jaegeuk Kim wrote:

> This adds the implementation of superblock operations for f2fs, which includes
> - init_f2fs_fs/exit_f2fs_fs
> - f2fs_mount
> - super_operations of f2fs
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@xxxxxxxxxxx>
> ---
> fs/f2fs/super.c |  590 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 590 insertions(+)
> create mode 100644 fs/f2fs/super.c
> 
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> new file mode 100644
> index 0000000..8e608a0
> --- /dev/null
> +++ b/fs/f2fs/super.c
> @@ -0,0 +1,590 @@
> +/**
> + * fs/f2fs/super.c
> + *
> + * Copyright (c) 2012 Samsung Electronics Co., Ltd.
> + *             http://www.samsung.com/
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/fs.h>
> +#include <linux/statfs.h>
> +#include <linux/proc_fs.h>
> +#include <linux/buffer_head.h>
> +#include <linux/backing-dev.h>
> +#include <linux/kthread.h>
> +#include <linux/parser.h>
> +#include <linux/mount.h>
> +#include <linux/seq_file.h>
> +#include <linux/f2fs_fs.h>
> +
> +#include "f2fs.h"
> +#include "node.h"
> +#include "xattr.h"
> +
> +static struct kmem_cache *f2fs_inode_cachep;
> +static struct proc_dir_entry *f2fs_proc_root;
> +
> +enum {
> +	Opt_gc_background_off,
> +	Opt_disable_roll_forward,
> +	Opt_discard,
> +	Opt_noheap,
> +	Opt_nouser_xattr,
> +	Opt_noacl,
> +	Opt_active_logs,
> +	Opt_disable_ext_identify,
> +	Opt_err,
> +};
> +
> +static match_table_t f2fs_tokens = {
> +	{Opt_gc_background_off, "background_gc_off"},
> +	{Opt_disable_roll_forward, "disable_roll_forward"},
> +	{Opt_discard, "discard"},
> +	{Opt_noheap, "no_heap"},
> +	{Opt_nouser_xattr, "nouser_xattr"},
> +	{Opt_noacl, "noacl"},
> +	{Opt_active_logs, "active_logs=%u"},
> +	{Opt_disable_ext_identify, "disable_ext_identify"},
> +	{Opt_err, NULL},
> +};
> +
> +static void init_once(void *foo)
> +{
> +	struct f2fs_inode_info *fi = (struct f2fs_inode_info *) foo;
> +
> +	memset(fi, 0, sizeof(*fi));
> +	inode_init_once(&fi->vfs_inode);
> +}
> +
> +static struct inode *f2fs_alloc_inode(struct super_block *sb)
> +{
> +	struct f2fs_inode_info *fi;
> +
> +	fi = kmem_cache_alloc(f2fs_inode_cachep, GFP_NOFS | __GFP_ZERO);
> +	if (!fi)
> +		return NULL;
> +
> +	init_once((void *) fi);
> +
> +	/* Initilize f2fs-specific inode info */
> +	fi->vfs_inode.i_version = 1;
> +	atomic_set(&fi->dirty_dents, 0);
> +	fi->current_depth = 1;
> +	fi->i_advise = 0;
> +	rwlock_init(&fi->ext.ext_lock);
> +
> +	set_inode_flag(fi, FI_NEW_INODE);
> +
> +	return &fi->vfs_inode;
> +}
> +
> +static void f2fs_i_callback(struct rcu_head *head)
> +{
> +	struct inode *inode = container_of(head, struct inode, i_rcu);
> +	kmem_cache_free(f2fs_inode_cachep, F2FS_I(inode));
> +}
> +
> +void f2fs_destroy_inode(struct inode *inode)
> +{
> +	call_rcu(&inode->i_rcu, f2fs_i_callback);
> +}
> +
> +static void f2fs_put_super(struct super_block *sb)
> +{
> +	struct f2fs_sb_info *sbi = F2FS_SB(sb);
> +
> +#ifdef CONFIG_F2FS_STAT_FS
> +	if (sbi->s_proc) {
> +		f2fs_stat_exit(sbi);
> +		remove_proc_entry(sb->s_id, f2fs_proc_root);
> +	}
> +#endif
> +	stop_gc_thread(sbi);
> +
> +	write_checkpoint(sbi, false, true);
> +
> +	iput(sbi->node_inode);
> +	iput(sbi->meta_inode);
> +
> +	/* destroy f2fs internal modules */
> +	destroy_gc_manager(sbi);
> +	destroy_node_manager(sbi);
> +	destroy_segment_manager(sbi);
> +
> +	kfree(sbi->ckpt);
> +
> +	sb->s_fs_info = NULL;
> +	brelse(sbi->raw_super_buf);
> +	kfree(sbi);
> +}
> +
> +int f2fs_sync_fs(struct super_block *sb, int sync)
> +{
> +	struct f2fs_sb_info *sbi = F2FS_SB(sb);
> +	int ret = 0;
> +
> +	if (!sbi->s_dirty && !get_pages(sbi, F2FS_DIRTY_NODES))
> +		return 0;
> +
> +	if (sync)
> +		write_checkpoint(sbi, false, false);
> +
> +	return ret;
> +}
> +
> +static int f2fs_statfs(struct dentry *dentry, struct kstatfs *buf)
> +{
> +	struct super_block *sb = dentry->d_sb;
> +	struct f2fs_sb_info *sbi = F2FS_SB(sb);
> +	block_t total_count, user_block_count, start_count, ovp_count;
> +
> +	total_count = le64_to_cpu(sbi->raw_super->block_count);
> +	user_block_count = sbi->user_block_count;
> +	start_count = le32_to_cpu(sbi->raw_super->segment0_blkaddr);
> +	ovp_count = sbi->gc_info->overp_segment_count
> +					<< sbi->log_blocks_per_seg;
> +	buf->f_type = F2FS_SUPER_MAGIC;
> +	buf->f_bsize = sbi->blocksize;
> +
> +	buf->f_blocks = total_count - start_count;
> +	buf->f_bfree = buf->f_blocks - valid_user_blocks(sbi) - ovp_count;
> +	buf->f_bavail = user_block_count - valid_user_blocks(sbi);
> +
> +	buf->f_files = valid_inode_count(sbi);
> +	buf->f_ffree = sbi->total_node_count - valid_node_count(sbi);
> +
> +	buf->f_namelen = F2FS_MAX_NAME_LEN;
> +
> +	return 0;
> +}
> +
> +static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
> +{
> +	struct f2fs_sb_info *sbi = F2FS_SB(root->d_sb);
> +
> +	if (test_opt(sbi, BG_GC))
> +		seq_puts(seq, ",background_gc_on");
> +	else
> +		seq_puts(seq, ",background_gc_off");
> +	if (test_opt(sbi, DISABLE_ROLL_FORWARD))
> +		seq_puts(seq, ",disable_roll_forward");
> +	if (test_opt(sbi, DISCARD))
> +		seq_puts(seq, ",discard");
> +	if (test_opt(sbi, NOHEAP))
> +		seq_puts(seq, ",no_heap_alloc");
> +#ifdef CONFIG_F2FS_FS_XATTR
> +	if (test_opt(sbi, XATTR_USER))
> +		seq_puts(seq, ",user_xattr");
> +	else
> +		seq_puts(seq, ",nouser_xattr");
> +#endif
> +#ifdef CONFIG_F2FS_FS_POSIX_ACL
> +	if (test_opt(sbi, POSIX_ACL))
> +		seq_puts(seq, ",acl");
> +	else
> +		seq_puts(seq, ",noacl");
> +#endif
> +	if (test_opt(sbi, DISABLE_EXT_IDENTIFY))
> +		seq_puts(seq, ",disable_ext_indentify");
> +
> +	seq_printf(seq, ",active_logs=%u", sbi->active_logs);
> +
> +	return 0;
> +}
> +
> +static struct super_operations f2fs_sops = {
> +	.alloc_inode	= f2fs_alloc_inode,
> +	.destroy_inode	= f2fs_destroy_inode,
> +	.write_inode	= f2fs_write_inode,
> +	.show_options	= f2fs_show_options,
> +	.evict_inode	= f2fs_evict_inode,
> +	.put_super	= f2fs_put_super,
> +	.sync_fs	= f2fs_sync_fs,
> +	.statfs		= f2fs_statfs,
> +};
> +
> +static int parse_options(struct f2fs_sb_info *sbi, char *options)
> +{
> +	substring_t args[MAX_OPT_ARGS];
> +	char *p;
> +	int arg = 0;
> +
> +	if (!options)
> +		return 0;
> +
> +	while ((p = strsep(&options, ",")) != NULL) {
> +		int token;
> +		if (!*p)
> +			continue;
> +		/*
> +		 * Initialize args struct so we know whether arg was
> +		 * found; some options take optional arguments.
> +		 */
> +		args[0].to = args[0].from = NULL;
> +		token = match_token(p, f2fs_tokens, args);
> +
> +		switch (token) {
> +		case Opt_gc_background_off:
> +			clear_opt(sbi, BG_GC);
> +			break;
> +		case Opt_disable_roll_forward:
> +			set_opt(sbi, DISABLE_ROLL_FORWARD);
> +			break;
> +		case Opt_discard:
> +			set_opt(sbi, DISCARD);
> +			break;
> +		case Opt_noheap:
> +			set_opt(sbi, NOHEAP);
> +			break;
> +#ifdef CONFIG_F2FS_FS_XATTR
> +		case Opt_nouser_xattr:
> +			clear_opt(sbi, XATTR_USER);
> +			break;
> +#else
> +		case Opt_nouser_xattr:
> +			pr_info("nouser_xattr options not supported\n");
> +			break;
> +#endif
> +#ifdef CONFIG_F2FS_FS_POSIX_ACL
> +		case Opt_noacl:
> +			clear_opt(sbi, POSIX_ACL);
> +			break;
> +#else
> +		case Opt_noacl:
> +			pr_info("noacl options not supported\n");
> +			break;
> +#endif
> +		case Opt_active_logs:
> +			if (args->from && match_int(args, &arg))
> +				return -EINVAL;
> +			if (arg != 2 && arg != 4 && arg != 6)
> +				return -EINVAL;
> +			sbi->active_logs = arg;
> +			break;
> +		case Opt_disable_ext_identify:
> +			set_opt(sbi, DISABLE_EXT_IDENTIFY);
> +			break;
> +		default:
> +			return -EINVAL;
> +		}
> +	}
> +	return 0;
> +}
> +
> +static loff_t max_file_size(unsigned bits)
> +{
> +	loff_t result = ADDRS_PER_INODE;
> +	loff_t leaf_count = ADDRS_PER_BLOCK;
> +
> +	result += (leaf_count * 2);
> +
> +	leaf_count *= NIDS_PER_BLOCK;
> +	result += (leaf_count * 2);
> +
> +	leaf_count *= NIDS_PER_BLOCK;
> +	result += (leaf_count * 2);
> +
> +	result <<= bits;
> +	return result;
> +}

I think that it needs to comment logic of max_file_size() function. It is not so clear why it needs to multiply leaf_count on 2.

> +
> +static int sanity_check_raw_super(struct f2fs_super_block *raw_super)
> +{
> +	unsigned int blocksize;
> +
> +	if (F2FS_SUPER_MAGIC != le32_to_cpu(raw_super->magic))
> +		return 1;
> +
> +	/* Currently, support only 4KB block size */
> +	blocksize = 1 << le32_to_cpu(raw_super->log_blocksize);
> +	if (blocksize != PAGE_CACHE_SIZE)
> +		return 1;
> +	if (le32_to_cpu(raw_super->log_sectorsize) != 9)

I think it makes sense to have special declaration for hardcoded 9.

> +		return 1;
> +	if (le32_to_cpu(raw_super->log_sectors_per_block) != 3)

I think it makes sense to have special declaration for hardcoded 3.

> +		return 1;
> +	return 0;
> +}
> +
> +static int sanity_check_ckpt(struct f2fs_super_block *raw_super,
> +				struct f2fs_checkpoint *ckpt)
> +{
> +	unsigned int total, fsmeta;
> +
> +	total = le32_to_cpu(raw_super->segment_count);
> +	fsmeta = le32_to_cpu(raw_super->segment_count_ckpt);
> +	fsmeta += le32_to_cpu(raw_super->segment_count_sit);
> +	fsmeta += le32_to_cpu(raw_super->segment_count_nat);
> +	fsmeta += le32_to_cpu(ckpt->rsvd_segment_count);
> +	fsmeta += le32_to_cpu(raw_super->segment_count_ssa);
> +
> +	if (fsmeta >= total)
> +		return 1;
> +	return 0;
> +}
> +
> +static void init_sb_info(struct f2fs_sb_info *sbi)
> +{
> +	struct f2fs_super_block *raw_super = sbi->raw_super;
> +	int i;
> +
> +	sbi->log_sectorsize = le32_to_cpu(raw_super->log_sectorsize);
> +	sbi->log_sectors_per_block =
> +		le32_to_cpu(raw_super->log_sectors_per_block);
> +	sbi->log_blocksize = le32_to_cpu(raw_super->log_blocksize);
> +	sbi->blocksize = 1 << sbi->log_blocksize;
> +	sbi->log_blocks_per_seg = le32_to_cpu(raw_super->log_blocks_per_seg);
> +	sbi->blocks_per_seg = 1 << sbi->log_blocks_per_seg;
> +	sbi->segs_per_sec = le32_to_cpu(raw_super->segs_per_sec);
> +	sbi->secs_per_zone = le32_to_cpu(raw_super->secs_per_zone);
> +	sbi->total_sections = le32_to_cpu(raw_super->section_count);
> +	sbi->total_node_count =
> +		(le32_to_cpu(raw_super->segment_count_nat) / 2)
> +			* sbi->blocks_per_seg * NAT_ENTRY_PER_BLOCK;
> +	sbi->root_ino_num = le32_to_cpu(raw_super->root_ino);
> +	sbi->node_ino_num = le32_to_cpu(raw_super->node_ino);
> +	sbi->meta_ino_num = le32_to_cpu(raw_super->meta_ino);
> +
> +	for (i = 0; i < NR_COUNT_TYPE; i++)
> +		atomic_set(&sbi->nr_pages[i], 0);
> +}
> +
> +static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
> +{
> +	struct f2fs_sb_info *sbi;
> +	struct f2fs_super_block *raw_super;
> +	struct buffer_head *raw_super_buf;
> +	struct inode *root;
> +	int i;
> +
> +	/* allocate memory for f2fs-specific super block info */
> +	sbi = kzalloc(sizeof(struct f2fs_sb_info), GFP_KERNEL);
> +	if (!sbi)
> +		return -ENOMEM;
> +
> +	/* set a temporary block size */
> +	if (!sb_set_blocksize(sb, F2FS_BLKSIZE))
> +		goto free_sbi;
> +
> +	/* read f2fs raw super block */
> +	raw_super_buf = sb_bread(sb, F2FS_SUPER_OFFSET);
> +	if (!raw_super_buf)
> +		goto free_sbi;
> +	raw_super = (struct f2fs_super_block *) ((char *)raw_super_buf->b_data);
> +
> +	/* init some FS parameters */
> +	sbi->active_logs = NR_CURSEG_TYPE;
> +
> +	set_opt(sbi, BG_GC);
> +
> +#ifdef CONFIG_F2FS_FS_XATTR
> +	set_opt(sbi, XATTR_USER);
> +#endif
> +#ifdef CONFIG_F2FS_FS_POSIX_ACL
> +	set_opt(sbi, POSIX_ACL);
> +#endif
> +	/* parse mount options */
> +	if (parse_options(sbi, (char *)data))
> +		goto free_sb_buf;
> +
> +	/* sanity checking of raw super */
> +	if (sanity_check_raw_super(raw_super))
> +		goto free_sb_buf;
> +
> +	sb->s_maxbytes = max_file_size(raw_super->log_blocksize);
> +	sb->s_max_links = F2FS_LINK_MAX;
> +
> +	sb->s_op = &f2fs_sops;
> +	sb->s_xattr = f2fs_xattr_handlers;
> +	sb->s_magic = F2FS_SUPER_MAGIC;
> +	sb->s_fs_info = sbi;
> +	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
> +		(test_opt(sbi, POSIX_ACL) ? MS_POSIXACL : 0);
> +
> +	/* init f2fs-specific super block info */
> +	sbi->sb = sb;
> +	sbi->raw_super = raw_super;
> +	sbi->raw_super_buf = raw_super_buf;
> +	mutex_init(&sbi->gc_mutex);
> +	mutex_init(&sbi->write_inode);
> +	mutex_init(&sbi->writepages);
> +	mutex_init(&sbi->cp_mutex);
> +	for (i = 0; i < NR_LOCK_TYPE; i++)
> +		mutex_init(&sbi->fs_lock[i]);
> +	sbi->por_doing = 0;
> +	spin_lock_init(&sbi->stat_lock);
> +	init_rwsem(&sbi->bio_sem);
> +	init_sb_info(sbi);
> +
> +	/* get an inode for meta space */
> +	sbi->meta_inode = f2fs_iget(sb, F2FS_META_INO(sbi));
> +	if (IS_ERR(sbi->meta_inode))
> +		goto free_sb_buf;
> +
> +	if (get_valid_checkpoint(sbi))
> +		goto free_meta_inode;
> +
> +	/* sanity checking of checkpoint */
> +	if (sanity_check_ckpt(raw_super, sbi->ckpt))
> +		goto free_cp;
> +
> +	sbi->total_valid_node_count =
> +				le32_to_cpu(sbi->ckpt->valid_node_count);
> +	sbi->total_valid_inode_count =
> +				le32_to_cpu(sbi->ckpt->valid_inode_count);
> +	sbi->user_block_count = le64_to_cpu(sbi->ckpt->user_block_count);
> +	sbi->total_valid_block_count =
> +				le64_to_cpu(sbi->ckpt->valid_block_count);
> +	sbi->last_valid_block_count = sbi->total_valid_block_count;
> +	sbi->alloc_valid_block_count = 0;
> +	INIT_LIST_HEAD(&sbi->dir_inode_list);
> +	spin_lock_init(&sbi->dir_inode_lock);
> +
> +	/* init super block */
> +	if (!sb_set_blocksize(sb, sbi->blocksize))
> +		goto free_cp;
> +
> +	init_orphan_info(sbi);
> +
> +	/* setup f2fs internal modules */
> +	if (build_segment_manager(sbi))
> +		goto free_sm;
> +	if (build_node_manager(sbi))
> +		goto free_nm;
> +	if (build_gc_manager(sbi))
> +		goto free_gc;
> +
> +	/* get an inode for node space */
> +	sbi->node_inode = f2fs_iget(sb, F2FS_NODE_INO(sbi));
> +	if (IS_ERR(sbi->node_inode))
> +		goto free_gc;
> +
> +	/* if there are nt orphan nodes free them */
> +	if (recover_orphan_inodes(sbi))
> +		goto free_node_inode;
> +
> +	/* read root inode and dentry */
> +	root = f2fs_iget(sb, F2FS_ROOT_INO(sbi));
> +	if (IS_ERR(root))
> +		goto free_node_inode;
> +	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size)
> +		goto free_root_inode;
> +
> +	sb->s_root = d_make_root(root); /* allocate root dentry */
> +	if (!sb->s_root)
> +		goto free_root_inode;
> +
> +	/* recover fsynced data */
> +	if (!test_opt(sbi, DISABLE_ROLL_FORWARD))
> +		recover_fsync_data(sbi);
> +
> +	/* After POR, we can run background GC thread */
> +	if (start_gc_thread(sbi))
> +		goto fail;
> +
> +#ifdef CONFIG_F2FS_STAT_FS
> +	if (f2fs_proc_root) {
> +		sbi->s_proc = proc_mkdir(sb->s_id, f2fs_proc_root);
> +		if (f2fs_stat_init(sbi))
> +			goto fail;
> +	}
> +#endif
> +	return 0;
> +fail:
> +	stop_gc_thread(sbi);
> +free_root_inode:
> +	make_bad_inode(root);
> +	iput(root);
> +free_node_inode:
> +	make_bad_inode(sbi->node_inode);
> +	iput(sbi->node_inode);
> +free_gc:
> +	destroy_gc_manager(sbi);
> +free_nm:
> +	destroy_node_manager(sbi);
> +free_sm:
> +	destroy_segment_manager(sbi);
> +free_cp:
> +	kfree(sbi->ckpt);
> +free_meta_inode:
> +	make_bad_inode(sbi->meta_inode);
> +	iput(sbi->meta_inode);
> +free_sb_buf:
> +	brelse(raw_super_buf);
> +free_sbi:
> +	kfree(sbi);
> +	return -EINVAL;

The reason of failing in fill_super() can be different but this function report -EINVAL always, as I understand. I think that it is not fully correct way of reporting about failing.

> +}
> +
> +static struct dentry *f2fs_mount(struct file_system_type *fs_type, int flags,
> +			const char *dev_name, void *data)
> +{
> +	return mount_bdev(fs_type, flags, dev_name, data, f2fs_fill_super);
> +}
> +
> +static struct file_system_type f2fs_fs_type = {
> +	.owner		= THIS_MODULE,
> +	.name		= "f2fs",
> +	.mount		= f2fs_mount,
> +	.kill_sb	= kill_block_super,
> +	.fs_flags	= FS_REQUIRES_DEV,
> +};
> +
> +static int init_inodecache(void)
> +{
> +	f2fs_inode_cachep = f2fs_kmem_cache_create("f2fs_inode_cache",
> +			sizeof(struct f2fs_inode_info), NULL);
> +	if (f2fs_inode_cachep == NULL)
> +		return -ENOMEM;
> +	return 0;
> +}
> +
> +static void destroy_inodecache(void)
> +{
> +	/*
> +	 * Make sure all delayed rcu free inodes are flushed before we
> +	 * destroy cache.
> +	 */
> +	rcu_barrier();
> +	kmem_cache_destroy(f2fs_inode_cachep);
> +}
> +
> +static int __init init_f2fs_fs(void)
> +{
> +	if (init_inodecache())
> +		goto fail;
> +	if (create_node_manager_caches())
> +		goto fail;
> +	if (create_gc_caches())
> +		goto fail;
> +	if (create_checkpoint_caches())
> +		goto fail;
> +	if (register_filesystem(&f2fs_fs_type))
> +		return -EBUSY;

Why EBUSY? Usually, it returns error code from register_filesystem().

> +
> +	f2fs_proc_root = proc_mkdir("fs/f2fs", NULL);
> +	return 0;
> +fail:
> +	return -ENOMEM;
> +}
> +
> +static void __exit exit_f2fs_fs(void)
> +{
> +	remove_proc_entry("fs/f2fs", NULL);
> +	unregister_filesystem(&f2fs_fs_type);
> +	destroy_checkpoint_caches();
> +	destroy_gc_caches();
> +	destroy_node_manager_caches();
> +	destroy_inodecache();
> +}
> +
> +module_init(init_f2fs_fs)
> +module_exit(exit_f2fs_fs)
> +
> +MODULE_AUTHOR("Samsung Electronics's Praesto Team");
> +MODULE_DESCRIPTION("Flash Friendly File System");
> +MODULE_LICENSE("GPL");
> -- 
> 1.7.9.5
> 
> 
> 
> 
> ---
> Jaegeuk Kim
> Samsung
> 
> 
> 
> --
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With the best regards,
Vyacheslav Dubeyko.

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