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Message-ID: <20240828110444.7wvo4ev32m5pewo7@quack3>
Date: Wed, 28 Aug 2024 13:04:44 +0200
From: Jan Kara <jack@...e.cz>
To: zhangshida <starzhangzsd@...il.com>
Cc: tytso@....edu, adilger.kernel@...ger.ca, jack@...e.com,
linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org,
zhangshida@...inos.cn, Jan Kara <jack@...e.cz>
Subject: Re: [PATCH 1/2] ext4: hoist ext4_block_write_begin and replace the
__block_write_begin
On Fri 23-08-24 09:33:28, zhangshida wrote:
> From: Shida Zhang <zhangshida@...inos.cn>
>
> Using __block_write_begin() make it inconvenient to journal the
> user data dirty process. We can't tell the block layer maintainer,
> ‘Hey, we want to trace the dirty user data in ext4, can we add some
> special code for ext4 in __block_write_begin?’:P
>
> So use ext4_block_write_begin() instead.
>
> The two functions are basically doing the same thing except for the
> fscrypt related code. Narrow the scope of CONFIG_FS_ENCRYPTION so as
> to allow ext4_block_write_begin() to function like __block_write_begin
> when the config is disabled.
> And hoist the ext4_block_write_begin so that it can be used in other
> files.
>
> Suggested-by: Jan Kara <jack@...e.cz>
> Signed-off-by: Shida Zhang <zhangshida@...inos.cn>
Looks good to me! Feel free to add:
Reviewed-by: Jan Kara <jack@...e.cz>
Honza
> ---
> fs/ext4/ext4.h | 2 ++
> fs/ext4/inline.c | 10 +++++-----
> fs/ext4/inode.c | 23 ++++++-----------------
> 3 files changed, 13 insertions(+), 22 deletions(-)
>
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 08acd152261e..5f8257b68190 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -3851,6 +3851,8 @@ static inline int ext4_buffer_uptodate(struct buffer_head *bh)
> return buffer_uptodate(bh);
> }
>
> +extern int ext4_block_write_begin(struct folio *folio, loff_t pos, unsigned len,
> + get_block_t *get_block);
> #endif /* __KERNEL__ */
>
> #define EFSBADCRC EBADMSG /* Bad CRC detected */
> diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
> index e7a09a99837b..0a1a8431e281 100644
> --- a/fs/ext4/inline.c
> +++ b/fs/ext4/inline.c
> @@ -601,10 +601,10 @@ static int ext4_convert_inline_data_to_extent(struct address_space *mapping,
> goto out;
>
> if (ext4_should_dioread_nolock(inode)) {
> - ret = __block_write_begin(&folio->page, from, to,
> - ext4_get_block_unwritten);
> + ret = ext4_block_write_begin(folio, from, to,
> + ext4_get_block_unwritten);
> } else
> - ret = __block_write_begin(&folio->page, from, to, ext4_get_block);
> + ret = ext4_block_write_begin(folio, from, to, ext4_get_block);
>
> if (!ret && ext4_should_journal_data(inode)) {
> ret = ext4_walk_page_buffers(handle, inode,
> @@ -856,8 +856,8 @@ static int ext4_da_convert_inline_data_to_extent(struct address_space *mapping,
> goto out;
> }
>
> - ret = __block_write_begin(&folio->page, 0, inline_size,
> - ext4_da_get_block_prep);
> + ret = ext4_block_write_begin(folio, 0, inline_size,
> + ext4_da_get_block_prep);
> if (ret) {
> up_read(&EXT4_I(inode)->xattr_sem);
> folio_unlock(folio);
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 941c1c0d5c6e..6b15805ca88b 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -1041,9 +1041,8 @@ int do_journal_get_write_access(handle_t *handle, struct inode *inode,
> return ret;
> }
>
> -#ifdef CONFIG_FS_ENCRYPTION
> -static int ext4_block_write_begin(struct folio *folio, loff_t pos, unsigned len,
> - get_block_t *get_block)
> +int ext4_block_write_begin(struct folio *folio, loff_t pos, unsigned len,
> + get_block_t *get_block)
> {
> unsigned from = pos & (PAGE_SIZE - 1);
> unsigned to = from + len;
> @@ -1119,7 +1118,9 @@ static int ext4_block_write_begin(struct folio *folio, loff_t pos, unsigned len,
> }
> if (unlikely(err)) {
> folio_zero_new_buffers(folio, from, to);
> - } else if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
> + }
> +#ifdef CONFIG_FS_ENCRYPTION
> + else if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
> for (i = 0; i < nr_wait; i++) {
> int err2;
>
> @@ -1131,10 +1132,10 @@ static int ext4_block_write_begin(struct folio *folio, loff_t pos, unsigned len,
> }
> }
> }
> +#endif
>
> return err;
> }
> -#endif
>
> /*
> * To preserve ordering, it is essential that the hole instantiation and
> @@ -1216,19 +1217,11 @@ static int ext4_write_begin(struct file *file, struct address_space *mapping,
> /* In case writeback began while the folio was unlocked */
> folio_wait_stable(folio);
>
> -#ifdef CONFIG_FS_ENCRYPTION
> if (ext4_should_dioread_nolock(inode))
> ret = ext4_block_write_begin(folio, pos, len,
> ext4_get_block_unwritten);
> else
> ret = ext4_block_write_begin(folio, pos, len, ext4_get_block);
> -#else
> - if (ext4_should_dioread_nolock(inode))
> - ret = __block_write_begin(&folio->page, pos, len,
> - ext4_get_block_unwritten);
> - else
> - ret = __block_write_begin(&folio->page, pos, len, ext4_get_block);
> -#endif
> if (!ret && ext4_should_journal_data(inode)) {
> ret = ext4_walk_page_buffers(handle, inode,
> folio_buffers(folio), from, to,
> @@ -2961,11 +2954,7 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
> if (IS_ERR(folio))
> return PTR_ERR(folio);
>
> -#ifdef CONFIG_FS_ENCRYPTION
> ret = ext4_block_write_begin(folio, pos, len, ext4_da_get_block_prep);
> -#else
> - ret = __block_write_begin(&folio->page, pos, len, ext4_da_get_block_prep);
> -#endif
> if (ret < 0) {
> folio_unlock(folio);
> folio_put(folio);
> --
> 2.33.0
>
--
Jan Kara <jack@...e.com>
SUSE Labs, CR
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