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Message-ID: <001801d5c743$c9c058e0$5d410aa0$@samsung.com>
Date:   Fri, 10 Jan 2020 08:23:23 +0900
From:   "Namjae Jeon" <namjae.jeon@...sung.com>
To:     "'Christoph Hellwig'" <hch@....de>
Cc:     <linux-kernel@...r.kernel.org>, <linux-fsdevel@...r.kernel.org>,
        <gregkh@...uxfoundation.org>, <valdis.kletnieks@...edu>,
        <sj1557.seo@...sung.com>, <linkinjeon@...il.com>,
        <pali.rohar@...il.com>
Subject: RE: [PATCH v9 03/13] exfat: add inode operations

> > +#include "exfat_fs.h"
> > +
> > +/* 2-level option flag */
> > +enum {
> > +	BMAP_NOT_CREATE,
> > +	BMAP_ADD_CLUSTER,
> > +};
> 
> I looked at how this flag is used and found the get_block code a little
> confusing.  Let me know what you think of the following untested patch to
> streamline that area:
I will check and test this patch.

Thanks!

> 
> 
> diff --git a/fs/exfat/inode.c b/fs/exfat/inode.c index
> c2b04537cb24..ccf9700c6a55 100644
> --- a/fs/exfat/inode.c
> +++ b/fs/exfat/inode.c
> @@ -17,12 +17,6 @@
>  #include "exfat_raw.h"
>  #include "exfat_fs.h"
> 
> -/* 2-level option flag */
> -enum {
> -	BMAP_NOT_CREATE,
> -	BMAP_ADD_CLUSTER,
> -};
> -
>  static int __exfat_write_inode(struct inode *inode, int sync)  {
>  	int ret = -EIO;
> @@ -298,109 +292,91 @@ static int exfat_map_cluster(struct inode *inode,
> unsigned int clu_offset,
>  	return 0;
>  }
> 
> -static int exfat_bmap(struct inode *inode, sector_t sector, sector_t
> *phys,
> -		unsigned long *mapped_blocks, int *create)
> +static int exfat_map_new_buffer(struct exfat_inode_info *ei,
> +		struct buffer_head *bh, loff_t pos)
>  {
> -	struct super_block *sb = inode->i_sb;
> -	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> -	sector_t last_block;
> -	unsigned int cluster, clu_offset, sec_offset;
> -	int err = 0;
> -
> -	*phys = 0;
> -	*mapped_blocks = 0;
> -
> -	last_block = EXFAT_B_TO_BLK_ROUND_UP(i_size_read(inode), sb);
> -	if (sector >= last_block && *create == BMAP_NOT_CREATE)
> -		return 0;
> -
> -	/* Is this block already allocated? */
> -	clu_offset = sector >> sbi->sect_per_clus_bits;  /* cluster offset
> */
> -
> -	err = exfat_map_cluster(inode, clu_offset, &cluster,
> -		*create & BMAP_ADD_CLUSTER);
> -	if (err) {
> -		if (err != -ENOSPC)
> -			return -EIO;
> -		return err;
> -	}
> -
> -	if (cluster != EXFAT_EOF_CLUSTER) {
> -		/* sector offset in cluster */
> -		sec_offset = sector & (sbi->sect_per_clus - 1);
> -
> -		*phys = exfat_cluster_to_sector(sbi, cluster) + sec_offset;
> -		*mapped_blocks = sbi->sect_per_clus - sec_offset;
> -	}
> +	if (buffer_delay(bh) && pos > ei->i_size_aligned)
> +		return -EIO;
> +	set_buffer_new(bh);
> 
> -	if (sector < last_block)
> -		*create = BMAP_NOT_CREATE;
> +	/*
> +	 * Adjust i_size_aligned if i_size_ondisk is bigger than it.
> +	 * (i.e. non-DA)
> +	 */
> +	if (ei->i_size_ondisk > ei->i_size_aligned)
> +		ei->i_size_aligned = ei->i_size_ondisk;
>  	return 0;
>  }
> 
>  static int exfat_get_block(struct inode *inode, sector_t iblock,
>  		struct buffer_head *bh_result, int create)  {
> +	struct exfat_inode_info *ei = EXFAT_I(inode);
>  	struct super_block *sb = inode->i_sb;
> +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
>  	unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
>  	int err = 0;
> -	unsigned long mapped_blocks;
> -	sector_t phys;
> +	unsigned long mapped_blocks = 0;
> +	unsigned int cluster, sec_offset;
> +	sector_t last_block;
> +	sector_t phys = 0;
>  	loff_t pos;
> -	int bmap_create = create ? BMAP_ADD_CLUSTER : BMAP_NOT_CREATE;
> +
> +	mutex_lock(&sbi->s_lock);
> +	last_block = EXFAT_B_TO_BLK_ROUND_UP(i_size_read(inode), sb);
> +	if (iblock >= last_block && !create)
> +		goto done;
> 
> -	mutex_lock(&EXFAT_SB(sb)->s_lock);
> -	err = exfat_bmap(inode, iblock, &phys, &mapped_blocks,
> &bmap_create);
> +	/* Is this block already allocated? */
> +	err = exfat_map_cluster(inode, iblock >> sbi->sect_per_clus_bits,
> +				&cluster, create);
>  	if (err) {
> -		if (err != -ENOSPC)
> -			exfat_fs_error_ratelimit(sb,
> -				"failed to bmap (inode : %p iblock : %llu,
> err : %d)",
> -				inode, (unsigned long long)iblock, err);
> +		if (err == -ENOSPC)
> +			goto unlock_ret;
> +
> +		exfat_fs_error_ratelimit(sb,
> +			"failed to bmap (inode : %p iblock : %llu, err :
%d)",
> +			inode, (unsigned long long)iblock, err);
>  		goto unlock_ret;
>  	}
> 
> -	if (phys) {
> -		max_blocks = min(mapped_blocks, max_blocks);
> -
> -		/* Treat newly added block / cluster */
> -		if (bmap_create || buffer_delay(bh_result)) {
> -			/* Update i_size_ondisk */
> -			pos = EXFAT_BLK_TO_B((iblock + 1), sb);
> -			if (EXFAT_I(inode)->i_size_ondisk < pos)
> -				EXFAT_I(inode)->i_size_ondisk = pos;
> -
> -			if (bmap_create) {
> -				if (buffer_delay(bh_result) &&
> -				    pos > EXFAT_I(inode)->i_size_aligned) {
> -					exfat_fs_error(sb,
> -						"requested for bmap out of
> range(pos : (%llu) > i_size_aligned(%llu)\n",
> -						pos,
> -
EXFAT_I(inode)->i_size_aligned);
> -					err = -EIO;
> -					goto unlock_ret;
> -				}
> -				set_buffer_new(bh_result);
> -
> -				/*
> -				 * adjust i_size_aligned if i_size_ondisk is
> -				 * bigger than it. (i.e. non-DA)
> -				 */
> -				if (EXFAT_I(inode)->i_size_ondisk >
> -				    EXFAT_I(inode)->i_size_aligned) {
> -					EXFAT_I(inode)->i_size_aligned =
> -
EXFAT_I(inode)->i_size_ondisk;
> -				}
> -			}
> +	if (cluster == EXFAT_EOF_CLUSTER)
> +		goto done;
> +
> +	/* sector offset in cluster */
> +	sec_offset = iblock & (sbi->sect_per_clus - 1);
> +
> +	phys = exfat_cluster_to_sector(sbi, cluster) + sec_offset;
> +	mapped_blocks = sbi->sect_per_clus - sec_offset;
> +	max_blocks = min(mapped_blocks, max_blocks);
> 
> -			if (buffer_delay(bh_result))
> -				clear_buffer_delay(bh_result);
> +	/* Treat newly added block / cluster */
> +	if (iblock < last_block)
> +		create = 0;
> +
> +	if (create || buffer_delay(bh_result)) {
> +		pos = EXFAT_BLK_TO_B((iblock + 1), sb);
> +		if (ei->i_size_ondisk < pos)
> +			ei->i_size_ondisk = pos;
> +	}
> +
> +	if (create) {
> +		err = exfat_map_new_buffer(ei, bh_result, pos);
> +		if (err) {
> +			exfat_fs_error(sb,
> +				"requested for bmap out of range(pos :
(%llu) >
> i_size_aligned(%llu)\n",
> +				pos, ei->i_size_aligned);
> +			goto unlock_ret;
>  		}
> -		map_bh(bh_result, sb, phys);
>  	}
> 
> +	if (buffer_delay(bh_result))
> +		clear_buffer_delay(bh_result);
> +	map_bh(bh_result, sb, phys);
> +done:
>  	bh_result->b_size = EXFAT_BLK_TO_B(max_blocks, sb);
>  unlock_ret:
> -	mutex_unlock(&EXFAT_SB(sb)->s_lock);
> +	mutex_unlock(&sbi->s_lock);
>  	return err;
>  }
> 

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