Re: [PATCH 0/3 RESEND Rebased] readmirror feature

[Anand Jain <anand.jain@oracle.com>]

Ping?


On 26/6/19 4:33 PM, Anand Jain wrote:
> These patches are tested to be working fine.
> 
> Function call chain  __btrfs_map_block()->find_live_mirror() uses
> thread pid to determine the %mirror_num when the mirror_num=0.
> 
> This patch introduces a framework so that we can add policies to determine
> the %mirror_num. And adds the devid as the readmirror policy.
> 
> The property is stored as an extented attributes of root inode
> (BTRFS_FS_TREE_OBJECTID).
> User provided devid list is validated against the fs_devices::dev_list.
> 
>   For example:
>     Usage:
>       btrfs property set <mnt> readmirror devid<n>[,<m>...]
>       btrfs property set <mnt> readmirror ""
> 
>     mkfs.btrfs -fq -draid1 -mraid1 /dev/sd[b-d] && mount /dev/sdb /btrfs
>     btrfs prop set /btrfs readmirror devid1,2
>     btrfs prop get /btrfs readmirror
>      readmirror=devid1,2
>     getfattr -n btrfs.readmirror --absolute-names /btrfs
>      btrfs.readmirror="devid1,2"
>     btrfs prop set /btrfs readmirror ""
>     getfattr -n btrfs.readmirror --absolute-names /btrfs
>      /btrfs: btrfs.readmirror: No such attribute
>     btrfs prop get /btrfs readmirror
> 
> RFC->v1:
>    Drops pid as one of the readmirror policy choices and as usual remains
>    as default. And when the devid is reset the readmirror policy falls back
>    to pid.
>    Drops the mount -o readmirror idea, it can be added at a later point of
>    time.
>    Property now accepts more than 1 devid as readmirror device. As shown
>    in the example above.
> 
> Anand Jain (3):
>    btrfs: add inode pointer to prop_handler::validate()
>    btrfs: add readmirror property framework
>    btrfs: add readmirror devid property
> 
>   fs/btrfs/props.c   | 120 +++++++++++++++++++++++++++++++++++++++++++--
>   fs/btrfs/props.h   |   4 +-
>   fs/btrfs/volumes.c |  25 +++++++++-
>   fs/btrfs/volumes.h |   8 +++
>   fs/btrfs/xattr.c   |   2 +-
>   5 files changed, 150 insertions(+), 9 deletions(-)
>