From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Adam Borowski <kilobyte@angband.pl>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-btrfs@vger.kernel.org, Mark Fasheh <mfasheh@suse.de>
Subject: Re: [PATCH] vfs: allow FILE_EXTENT_SAME (dedupe_file_range) on a file opened ro
Date: Mon, 18 Jul 2016 19:41:30 -0700 [thread overview]
Message-ID: <20160719024129.GE2494@birch.djwong.org> (raw)
In-Reply-To: <1468793618-10496-1-git-send-email-kilobyte@angband.pl>
On Mon, Jul 18, 2016 at 12:13:38AM +0200, Adam Borowski wrote:
> Instead of checking the mode of the file descriptor, let's check whether it
> could have been opened rw. This allows fixing intermittent exec failures
> when deduping a live system: anyone trying to exec a file currently being
> deduped gets ETXTBSY.
>
> Issuing this ioctl on a ro file was already allowed for root/cap.
>
> Tested on btrfs and not-yet-merged xfs, as only them implement this ioctl.
>
> Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Could you please send an xfstest to test this aspect of the dedupe ioctl?
--D
> ---
> fs/read_write.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/read_write.c b/fs/read_write.c
> index 933b53a..df59dc6 100644
> --- a/fs/read_write.c
> +++ b/fs/read_write.c
> @@ -1723,7 +1723,7 @@ int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
>
> if (info->reserved) {
> info->status = -EINVAL;
> - } else if (!(is_admin || (dst_file->f_mode & FMODE_WRITE))) {
> + } else if (!(is_admin || !inode_permission(dst, MAY_WRITE))) {
> info->status = -EINVAL;
> } else if (file->f_path.mnt != dst_file->f_path.mnt) {
> info->status = -EXDEV;
> --
> 2.8.1
>
prev parent reply other threads:[~2016-07-19 2:41 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-17 22:13 [PATCH] vfs: allow FILE_EXTENT_SAME (dedupe_file_range) on a file opened ro Adam Borowski
2016-07-17 22:32 ` Adam Borowski
2016-07-18 19:51 ` Mark Fasheh
2016-07-19 2:41 ` Darrick J. Wong [this message]
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