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Date:   Mon, 11 Dec 2023 18:16:40 +0100
From:   Jan Kara <jack@suse.cz>
To:     Yu Kuai <yukuai1@huaweicloud.com>
Cc:     axboe@kernel.dk, roger.pau@citrix.com, colyli@suse.de,
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Subject: Re: [PATCH RFC v2 for-6.8/block 16/18] ext4: use new helper to read
 sb block
Message-ID: <20231211171640.teuuedr3dqzsvsmw@quack3>
References: <20231211140552.973290-1-yukuai1@huaweicloud.com>
 <20231211140808.975527-1-yukuai1@huaweicloud.com>
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On Mon 11-12-23 22:08:08, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@huawei.com>
> 
> Remove __ext4_sb_bread_gfp() and ext4_buffer_uptodate() that is defined
> by ext4, and convert to use common helper __bread_gfp2() and
> buffer_uptodate_or_error().
> 
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/ext4/ext4.h    | 13 -------------
>  fs/ext4/inode.c   |  8 ++++----
>  fs/ext4/super.c   | 45 ++++++++++-----------------------------------
>  fs/ext4/symlink.c |  2 +-
>  4 files changed, 15 insertions(+), 53 deletions(-)
> 
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index a5d784872303..8377f6c5264f 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -3824,19 +3824,6 @@ extern const struct iomap_ops ext4_iomap_ops;
>  extern const struct iomap_ops ext4_iomap_overwrite_ops;
>  extern const struct iomap_ops ext4_iomap_report_ops;
>  
> -static inline int ext4_buffer_uptodate(struct buffer_head *bh)
> -{
> -	/*
> -	 * If the buffer has the write error flag, we have failed
> -	 * to write out data in the block.  In this  case, we don't
> -	 * have to read the block because we may read the old data
> -	 * successfully.
> -	 */
> -	if (buffer_write_io_error(bh))
> -		set_buffer_uptodate(bh);
> -	return buffer_uptodate(bh);
> -}
> -
>  #endif	/* __KERNEL__ */
>  
>  #define EFSBADCRC	EBADMSG		/* Bad CRC detected */
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 61277f7f8722..efb0af6f02f7 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -887,7 +887,7 @@ struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
>  	bh = ext4_getblk(handle, inode, block, map_flags);
>  	if (IS_ERR(bh))
>  		return bh;
> -	if (!bh || ext4_buffer_uptodate(bh))
> +	if (!bh || buffer_uptodate_or_error(bh))
>  		return bh;
>  
>  	ret = ext4_read_bh_lock(bh, REQ_META | REQ_PRIO, true);
> @@ -915,7 +915,7 @@ int ext4_bread_batch(struct inode *inode, ext4_lblk_t block, int bh_count,
>  
>  	for (i = 0; i < bh_count; i++)
>  		/* Note that NULL bhs[i] is valid because of holes. */
> -		if (bhs[i] && !ext4_buffer_uptodate(bhs[i]))
> +		if (bhs[i] && !buffer_uptodate_or_error(bhs[i]))
>  			ext4_read_bh_lock(bhs[i], REQ_META | REQ_PRIO, false);
>  
>  	if (!wait)
> @@ -4392,11 +4392,11 @@ static int __ext4_get_inode_loc(struct super_block *sb, unsigned long ino,
>  	bh = sb_getblk(sb, block);
>  	if (unlikely(!bh))
>  		return -ENOMEM;
> -	if (ext4_buffer_uptodate(bh))
> +	if (buffer_uptodate_or_error(bh))
>  		goto has_buffer;
>  
>  	lock_buffer(bh);
> -	if (ext4_buffer_uptodate(bh)) {
> +	if (buffer_uptodate_or_error(bh)) {
>  		/* Someone brought it uptodate while we waited */
>  		unlock_buffer(bh);
>  		goto has_buffer;
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index c5fcf377ab1f..ae41204f52d4 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -180,7 +180,7 @@ void ext4_read_bh_nowait(struct buffer_head *bh, blk_opf_t op_flags,
>  {
>  	BUG_ON(!buffer_locked(bh));
>  
> -	if (ext4_buffer_uptodate(bh)) {
> +	if (buffer_uptodate_or_error(bh)) {
>  		unlock_buffer(bh);
>  		return;
>  	}
> @@ -191,7 +191,7 @@ int ext4_read_bh(struct buffer_head *bh, blk_opf_t op_flags, bh_end_io_t *end_io
>  {
>  	BUG_ON(!buffer_locked(bh));
>  
> -	if (ext4_buffer_uptodate(bh)) {
> +	if (buffer_uptodate_or_error(bh)) {
>  		unlock_buffer(bh);
>  		return 0;
>  	}
> @@ -214,49 +214,24 @@ int ext4_read_bh_lock(struct buffer_head *bh, blk_opf_t op_flags, bool wait)
>  	return ext4_read_bh(bh, op_flags, NULL);
>  }
>  
> -/*
> - * This works like __bread_gfp() except it uses ERR_PTR for error
> - * returns.  Currently with sb_bread it's impossible to distinguish
> - * between ENOMEM and EIO situations (since both result in a NULL
> - * return.
> - */
> -static struct buffer_head *__ext4_sb_bread_gfp(struct super_block *sb,
> -					       sector_t block,
> -					       blk_opf_t op_flags, gfp_t gfp)
> -{
> -	struct buffer_head *bh;
> -	int ret;
> -
> -	bh = sb_getblk_gfp(sb, block, gfp);
> -	if (bh == NULL)
> -		return ERR_PTR(-ENOMEM);
> -	if (ext4_buffer_uptodate(bh))
> -		return bh;
> -
> -	ret = ext4_read_bh_lock(bh, REQ_META | op_flags, true);
> -	if (ret) {
> -		put_bh(bh);
> -		return ERR_PTR(ret);
> -	}
> -	return bh;
> -}
> -
>  struct buffer_head *ext4_sb_bread(struct super_block *sb, sector_t block,
>  				   blk_opf_t op_flags)
>  {
> -	gfp_t gfp = mapping_gfp_constraint(sb->s_bdev->bd_inode->i_mapping,
> -			~__GFP_FS) | __GFP_MOVABLE;
> +	struct buffer_head *bh = __bread_gfp2(sb->s_bdev, block,
> +					      sb->s_blocksize,
> +					      REQ_META | op_flags,
> +					      __GFP_MOVABLE);
>  
> -	return __ext4_sb_bread_gfp(sb, block, op_flags, gfp);
> +	return bh ? bh : ERR_PTR(-EIO);
>  }
>  
>  struct buffer_head *ext4_sb_bread_unmovable(struct super_block *sb,
>  					    sector_t block)
>  {
> -	gfp_t gfp = mapping_gfp_constraint(sb->s_bdev->bd_inode->i_mapping,
> -			~__GFP_FS);
> +	struct buffer_head *bh = __bread_gfp2(sb->s_bdev, block,
> +					      sb->s_blocksize, 0, 0);
>  
> -	return __ext4_sb_bread_gfp(sb, block, 0, gfp);
> +	return bh ? bh : ERR_PTR(-EIO);
>  }
>  
>  void ext4_sb_breadahead_unmovable(struct super_block *sb, sector_t block)
> diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
> index 75bf1f88843c..49e918221aac 100644
> --- a/fs/ext4/symlink.c
> +++ b/fs/ext4/symlink.c
> @@ -94,7 +94,7 @@ static const char *ext4_get_link(struct dentry *dentry, struct inode *inode,
>  		bh = ext4_getblk(NULL, inode, 0, EXT4_GET_BLOCKS_CACHED_NOWAIT);
>  		if (IS_ERR(bh))
>  			return ERR_CAST(bh);
> -		if (!bh || !ext4_buffer_uptodate(bh))
> +		if (!bh || !buffer_uptodate_or_error(bh))
>  			return ERR_PTR(-ECHILD);
>  	} else {
>  		bh = ext4_bread(NULL, inode, 0, 0);
> -- 
> 2.39.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR