linux-ext4 - Re: [PATCH 01/11] ext4: Factor out checks from ext4_file_write

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 3 Nov 2016 15:04:40 -0600
From:   Ross Zwisler <ross.zwisler@...ux.intel.com>
To:     Jan Kara <jack@...e.cz>
Cc:     linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        Dave Chinner <david@...morbit.com>, Ted Tso <tytso@....edu>,
        linux-nvdimm@...ts.01.org
Subject: Re: [PATCH 01/11] ext4: Factor out checks from ext4_file_write_iter()

On Tue, Nov 01, 2016 at 10:06:11PM +0100, Jan Kara wrote:
> Factor out checks of 'from' and whether we are overwriting out of
> ext4_file_write_iter() so that the function is easier to follow.
> 
> Signed-off-by: Jan Kara <jack@...e.cz>
> ---
>  fs/ext4/file.c | 97 ++++++++++++++++++++++++++++++----------------------------
>  1 file changed, 50 insertions(+), 47 deletions(-)
> 
> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> index 2a822d30e73f..a6a7becb9465 100644
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -88,6 +88,51 @@ ext4_unaligned_aio(struct inode *inode, struct iov_iter *from, loff_t pos)
>  	return 0;
>  }
>  
> +/* Is IO overwriting allocated and initialized blocks? */
> +static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len)
> +{
> +	struct ext4_map_blocks map;
> +	unsigned int blkbits = inode->i_blkbits;
> +	int err, blklen;
> +
> +	if (pos + len > i_size_read(inode))
> +		return false;
> +
> +	map.m_lblk = pos >> blkbits;
> +	map.m_len = EXT4_MAX_BLOCKS(len, pos, blkbits);
> +	blklen = map.m_len;
> +
> +	err = ext4_map_blocks(NULL, inode, &map, 0);
> +	/*
> +	 * 'err==len' means that all of blocks has been preallocated no matter
> +	 * they are initialized or not.  For excluding unwritten extents, we
> +	 * need to check m_flags.

Does it make sense to clean up this comment, since you're moving it anyway?

i.e.:

  'err==len' means that all of the blocks have been preallocated, regardless
  of whether they have been initialized or not.  To exclude unwritten extents
  we need to check m_flags.
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html