From: Anand Jain <anand.jain@oracle.com>
To: linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 1/3 v2 RFC] btrfs: total_devices vs num_devices
Date: Mon, 10 Mar 2014 09:58:48 +0800 [thread overview]
Message-ID: <531D1C58.90406@oracle.com> (raw)
In-Reply-To: <1394207319-13252-1-git-send-email-Anand.Jain@oracle.com>
Any comments on this set of patches ?
Thanks, Anand
On 07/03/2014 23:48, Anand Jain wrote:
> The intended usage of total_devices and num_devices
> should be recorded in the comments so that these
> two counters can be used correctly as originally
> intended.
>
> As of now there appears to be slight deviations/bugs
> from the original intention, the bugs are apparent
> that num_devices does not count seed devices where
> as total_devices does, but total_devices does not
> count the replacing devices where as num_devices does.
>
> So in this situation the ioctl(BTRFS_IOC_DEVICES_READY)
> will fails when there is seed FS. Next, applications
> using ioctl(BTRFS_IOC_FS_INFO) and ioctl(BTRFS_IOC_DEV_INFO)
> in conjunction to allocate the slots will also fail
> as former depend on the num_devices where as latter
> would match total_devices (except when replace is running).
>
> This patch will help have the clarity on usage
> of these two counter so that bugs related to this can
> be fixed.
>
> Signed-off-by: Anand Jain <Anand.Jain@oracle.com>
> ---
> v2: edit commit
>
> fs/btrfs/volumes.h | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
> index 91b7596..99c71aa 100644
> --- a/fs/btrfs/volumes.h
> +++ b/fs/btrfs/volumes.h
> @@ -121,12 +121,18 @@ struct btrfs_fs_devices {
> /* the device with this id has the most recent copy of the super */
> u64 latest_devid;
> u64 latest_trans;
> + /* num_devices contains run time count of devices which are part
> + * of this FSID. (the FS devices + replacing devices + ?
> + */
> u64 num_devices;
> u64 open_devices;
> u64 rw_devices;
> u64 missing_devices;
> u64 total_rw_bytes;
> u64 num_can_discard;
> + /* total_devices contains static recorded count of device which
> + * are part of this FSID. (the FS devices + seed devices + ?
> + */
> u64 total_devices;
> struct block_device *latest_bdev;
>
>
prev parent reply other threads:[~2014-03-10 1:59 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-07 15:48 [PATCH 1/3 v2 RFC] btrfs: total_devices vs num_devices Anand Jain
2014-03-07 15:48 ` [PATCH 2/3 RFC] btrfs: total_devices should count replacing devices Anand Jain
2014-05-13 9:17 ` Wang Shilong
2014-05-14 8:30 ` Anand Jain
2014-05-16 14:11 ` Anand Jain
2014-03-07 15:48 ` [PATCH 3/3 RFC] btrfs: show_devname should not consider seed disk Anand Jain
2014-03-10 1:58 ` Anand Jain [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=531D1C58.90406@oracle.com \
--to=anand.jain@oracle.com \
--cc=linux-btrfs@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).