Re: [PATCH 1/2] ntfs: do not read ahead encrypted files

[liubaolin]

在 2026/10/12 14:20, Zhan Xusheng 写道:
> From: Zhan Xusheng <zhanxusheng@xxxxxxxxxx>
>
> ntfs_read_folio() refuses EFS-encrypted files with -EOPNOTSUPP because
> decryption is not implemented.  ntfs_readahead() has no NInoEncrypted()
> test and passes them to iomap_readahead(), which maps the runlist and
> fills the folios with the raw on-disk ciphertext.  The folios are
> marked uptodate, so the read that follows never reaches ->read_folio
> and returns ciphertext instead of -EOPNOTSUPP.
>
> ntfs_read_locked_inode() sets NInoEncrypted() and NInoNonResident() for
> a non-resident encrypted $DATA attribute and rejects the
> encrypted-and-compressed combination, so none of the three existing
> conditions fires.  read(), mmap(), splice() and fadvise() all populate
> the page cache through readahead.
>
> Skipping readahead leaves the folio unpopulated, so the read falls back
> to ntfs_read_folio() and gets the intended error.
>
> Signed-off-by: Zhan Xusheng <zhanxusheng@xxxxxxxxxx>
> Fixes: b041ca562526 ("ntfs: update iomap and address space operations")
> ---
>   fs/ntfs/aops.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/fs/ntfs/aops.c b/fs/ntfs/aops.c
> index 517d9a1563e7d..ad781674fef1a 100644
> --- a/fs/ntfs/aops.c
> +++ b/fs/ntfs/aops.c
> @@ -240,10 +240,11 @@ static void ntfs_readahead(struct readahead_control *rac)
>   	};
>   
>   	/*
> -	 * Resident files are not cached in the page cache,
> -	 * and readahead is not implemented for compressed files.
> +	 * Resident files are not cached in the page cache, readahead is not
> +	 * implemented for compressed files, and ntfs_read_folio() refuses
> +	 * encrypted files because decryption is not implemented.
>   	 */
> -	if (!NInoNonResident(ni) || NInoCompressed(ni) ||
> +	if (!NInoNonResident(ni) || NInoEncrypted(ni) || NInoCompressed(ni) ||
>   	    NInoWofCompressed(ni))
>   		return;
>   	iomap_readahead(&ntfs_read_iomap_ops, &ctx, NULL);

Looks good to me.

Reviewed-by: Baolin Liu <liubaolin@xxxxxxxxxx>