On 01/28, Eric Biggers wrote:
> From: Eric Biggers <[email protected]>
> 
> Encrypted files traditionally haven't supported DIO, due to the need to
> encrypt/decrypt the data.  However, when the encryption is implemented
> using inline encryption (blk-crypto) instead of the traditional
> filesystem-layer encryption, it is straightforward to support DIO.
> 
> Therefore, make f2fs support DIO on files that are using inline
> encryption.  Since f2fs uses iomap for DIO, and fscrypt support was
> already added to iomap DIO, this just requires two small changes:
> 
> - Let DIO proceed when supported, by checking fscrypt_dio_supported()
>   instead of assuming that encrypted files never support DIO.
> 
> - In f2fs_iomap_begin(), use fscrypt_limit_io_blocks() to limit the
>   length of the mapping in the rare case where a DUN discontiguity
>   occurs in the middle of an extent.  The iomap DIO implementation
>   requires this, since it assumes that it can submit a bio covering (up
>   to) the whole mapping, without checking fscrypt constraints itself.
> 
> Co-developed-by: Satya Tangirala <[email protected]>
> Signed-off-by: Satya Tangirala <[email protected]>
> Signed-off-by: Eric Biggers <[email protected]>

Acked-by: Jaegeuk Kim <[email protected]>

> ---
>  fs/f2fs/data.c | 7 +++++++
>  fs/f2fs/f2fs.h | 6 +++++-
>  2 files changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 8c417864c66ae..020d47f97969c 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -4044,6 +4044,13 @@ static int f2fs_iomap_begin(struct inode *inode, 
> loff_t offset, loff_t length,
>  
>       iomap->offset = blks_to_bytes(inode, map.m_lblk);
>  
> +     /*
> +      * When inline encryption is enabled, sometimes I/O to an encrypted file
> +      * has to be broken up to guarantee DUN contiguity.  Handle this by
> +      * limiting the length of the mapping returned.
> +      */
> +     map.m_len = fscrypt_limit_io_blocks(inode, map.m_lblk, map.m_len);
> +
>       if (map.m_flags & (F2FS_MAP_MAPPED | F2FS_MAP_UNWRITTEN)) {
>               iomap->length = blks_to_bytes(inode, map.m_len);
>               if (map.m_flags & F2FS_MAP_MAPPED) {
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index eb22fa91c2b26..db46f3cf0885d 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -4371,7 +4371,11 @@ static inline bool f2fs_force_buffered_io(struct inode 
> *inode,
>       struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>       int rw = iov_iter_rw(iter);
>  
> -     if (f2fs_post_read_required(inode))
> +     if (!fscrypt_dio_supported(iocb, iter))
> +             return true;
> +     if (fsverity_active(inode))
> +             return true;
> +     if (f2fs_compressed_file(inode))
>               return true;
>  
>       /* disallow direct IO if any of devices has unaligned blksize */
> -- 
> 2.35.0


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