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From: Dave Chinner <david@fromorbit.com>
To: Lukas Czerner <lczerner@redhat.com>
Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
	xfs@oss.sgi.com
Subject: Re: [PATCH 2/3 v2] fs: Prevent doing FALLOC_FL_ZERO_RANGE on append only file
Date: Wed, 16 Apr 2014 08:02:20 +1000	[thread overview]
Message-ID: <20140415220220.GR15995@dastard> (raw)
In-Reply-To: <1397580076-19826-2-git-send-email-lczerner@redhat.com>

On Tue, Apr 15, 2014 at 06:41:15PM +0200, Lukas Czerner wrote:
> Currently punch hole and collapse range fallocate operation are not
> allowed on append only file. This should be case for zero range as well.
> Fix it by allowing only pure fallocate (possibly with keep size set).
> 
> Signed-off-by: Lukas Czerner <lczerner@redhat.com>
> ---
> v2: Change the condition to be future proof as suggested by hch
> 
>  fs/open.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/open.c b/fs/open.c
> index 631aea81..fe48b2f 100644
> --- a/fs/open.c
> +++ b/fs/open.c
> @@ -254,11 +254,9 @@ int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
>  		return -EBADF;
>  
>  	/*
> -	 * It's not possible to punch hole or perform collapse range
> -	 * on append only file
> +	 * We can only allow pure fallocate on append only files
>  	 */
> -	if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_COLLAPSE_RANGE)
> -	    && IS_APPEND(inode))
> +	if (mode & ~FALLOC_FL_KEEP_SIZE && IS_APPEND(inode))

	if ((mode & ~FALLOC_FL_KEEP_SIZE) && IS_APPEND(inode))

gcc normally complains when you mix & and && in the same logic
statement without () to separate the logic. I agree with gcc here,
because the () indicate the intent of the logic and make it easy to
determine that the & and && haven't been mixed up or fat-fingered...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

WARNING: multiple messages have this Message-ID (diff)
From: Dave Chinner <david@fromorbit.com>
To: Lukas Czerner <lczerner@redhat.com>
Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
	xfs@oss.sgi.com
Subject: Re: [PATCH 2/3 v2] fs: Prevent doing FALLOC_FL_ZERO_RANGE on append only file
Date: Wed, 16 Apr 2014 08:02:20 +1000	[thread overview]
Message-ID: <20140415220220.GR15995@dastard> (raw)
In-Reply-To: <1397580076-19826-2-git-send-email-lczerner@redhat.com>

On Tue, Apr 15, 2014 at 06:41:15PM +0200, Lukas Czerner wrote:
> Currently punch hole and collapse range fallocate operation are not
> allowed on append only file. This should be case for zero range as well.
> Fix it by allowing only pure fallocate (possibly with keep size set).
> 
> Signed-off-by: Lukas Czerner <lczerner@redhat.com>
> ---
> v2: Change the condition to be future proof as suggested by hch
> 
>  fs/open.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/open.c b/fs/open.c
> index 631aea81..fe48b2f 100644
> --- a/fs/open.c
> +++ b/fs/open.c
> @@ -254,11 +254,9 @@ int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
>  		return -EBADF;
>  
>  	/*
> -	 * It's not possible to punch hole or perform collapse range
> -	 * on append only file
> +	 * We can only allow pure fallocate on append only files
>  	 */
> -	if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_COLLAPSE_RANGE)
> -	    && IS_APPEND(inode))
> +	if (mode & ~FALLOC_FL_KEEP_SIZE && IS_APPEND(inode))

	if ((mode & ~FALLOC_FL_KEEP_SIZE) && IS_APPEND(inode))

gcc normally complains when you mix & and && in the same logic
statement without () to separate the logic. I agree with gcc here,
because the () indicate the intent of the logic and make it easy to
determine that the & and && haven't been mixed up or fat-fingered...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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  reply	other threads:[~2014-04-15 22:02 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-15 16:41 [PATCH 1/3 v2] ext4: Remove unnecessary check for APPEND and IMMUTABLE Lukas Czerner
2014-04-15 16:41 ` [PATCH 2/3 v2] fs: Prevent doing FALLOC_FL_ZERO_RANGE on append only file Lukas Czerner
2014-04-15 22:02   ` Dave Chinner [this message]
2014-04-15 22:02     ` Dave Chinner
2014-04-16  2:51     ` Theodore Ts'o
2014-04-16  2:51       ` Theodore Ts'o
2014-04-16  8:29     ` Lukáš Czerner
2014-04-15 16:41 ` [PATCH 3/3 v2] fs: move falloc collapse range check into the filesystem methods Lukas Czerner
2014-04-16  2:55   ` Theodore Ts'o
2014-04-16  2:55     ` Theodore Ts'o

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