linux-kernel - Re: [PATCH v3] mm: add file_fdatawait_range and file_write_and

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Message-ID: <20170801095231.GE4215@quack2.suse.cz>
Date:   Tue, 1 Aug 2017 11:52:31 +0200
From:   Jan Kara <jack@...e.cz>
To:     Jeff Layton <jlayton@...nel.org>
Cc:     Alexander Viro <viro@...iv.linux.org.uk>, Jan Kara <jack@...e.cz>,
        "J . Bruce Fields" <bfields@...ldses.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, Matthew Wilcox <willy@...radead.org>,
        Bob Peterson <rpeterso@...hat.com>,
        Steven Whitehouse <swhiteho@...hat.com>,
        cluster-devel@...hat.com
Subject: Re: [PATCH v3] mm: add file_fdatawait_range and file_write_and_wait

On Mon 31-07-17 12:49:25, Jeff Layton wrote:
> From: Jeff Layton <jlayton@...hat.com>
> 
> Necessary now for gfs2_fsync and sync_file_range, but there will
> eventually be other callers.
> 
> Signed-off-by: Jeff Layton <jlayton@...hat.com>

Looks good to me. You can add:

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

								Honza

> ---
>  include/linux/fs.h | 11 ++++++++++-
>  mm/filemap.c       | 23 +++++++++++++++++++++++
>  2 files changed, 33 insertions(+), 1 deletion(-)
> 
> v3: make file_write_and_wait a wrapper around file_write_and_wait_range
> 
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 526b6a9f30d4..909210bd6366 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -2549,6 +2549,8 @@ static inline int filemap_fdatawait(struct address_space *mapping)
>  
>  extern bool filemap_range_has_page(struct address_space *, loff_t lstart,
>  				  loff_t lend);
> +extern int __must_check file_fdatawait_range(struct file *file, loff_t lstart,
> +						loff_t lend);
>  extern int filemap_write_and_wait(struct address_space *mapping);
>  extern int filemap_write_and_wait_range(struct address_space *mapping,
>  				        loff_t lstart, loff_t lend);
> @@ -2557,12 +2559,19 @@ extern int __filemap_fdatawrite_range(struct address_space *mapping,
>  extern int filemap_fdatawrite_range(struct address_space *mapping,
>  				loff_t start, loff_t end);
>  extern int filemap_check_errors(struct address_space *mapping);
> -
>  extern void __filemap_set_wb_err(struct address_space *mapping, int err);
> +
> +extern int __must_check file_fdatawait_range(struct file *file, loff_t lstart,
> +						loff_t lend);
>  extern int __must_check file_check_and_advance_wb_err(struct file *file);
>  extern int __must_check file_write_and_wait_range(struct file *file,
>  						loff_t start, loff_t end);
>  
> +static inline int file_write_and_wait(struct file *file)
> +{
> +	return file_write_and_wait_range(file, 0, LLONG_MAX);
> +}
> +
>  /**
>   * filemap_set_wb_err - set a writeback error on an address_space
>   * @mapping: mapping in which to set writeback error
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 953804b29a75..85dfe3bee324 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -476,6 +476,29 @@ int filemap_fdatawait_range(struct address_space *mapping, loff_t start_byte,
>  EXPORT_SYMBOL(filemap_fdatawait_range);
>  
>  /**
> + * file_fdatawait_range - wait for writeback to complete
> + * @file:		file pointing to address space structure to wait for
> + * @start_byte:		offset in bytes where the range starts
> + * @end_byte:		offset in bytes where the range ends (inclusive)
> + *
> + * Walk the list of under-writeback pages of the address space that file
> + * refers to, in the given range and wait for all of them.  Check error
> + * status of the address space vs. the file->f_wb_err cursor and return it.
> + *
> + * Since the error status of the file is advanced by this function,
> + * callers are responsible for checking the return value and handling and/or
> + * reporting the error.
> + */
> +int file_fdatawait_range(struct file *file, loff_t start_byte, loff_t end_byte)
> +{
> +	struct address_space *mapping = file->f_mapping;
> +
> +	__filemap_fdatawait_range(mapping, start_byte, end_byte);
> +	return file_check_and_advance_wb_err(file);
> +}
> +EXPORT_SYMBOL(file_fdatawait_range);
> +
> +/**
>   * filemap_fdatawait_keep_errors - wait for writeback without clearing errors
>   * @mapping: address space structure to wait for
>   *
> -- 
> 2.13.3
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR