On Thu, Aug 31, 2017 at 10:17:10PM +0800, Hou Tao wrote:
> It will be useful if there is a corresponding online uevent after
> a XFS filesystem has been mounted. A typical usage of the uevent
> is setting the error configuration for a specific XFS filesystem
> or all XFS filesystems by using udevd.
>
> The following is an example of udevd rule which will shutdown
> any XFS filesystem after the filesystem gets any IO error:
>
> ACTION=="online", SUBSYSTEM=="xfs", DEVPATH=="/fs/xfs/*", \
> RUN+="/bin/sh -c 'echo 0 > /sys%p/error/metadata/default/max_retries; \
> echo 0 > /sys%p/error/metadata/EIO/max_retries; \
> echo 0 > /sys%p/error/metadata/ENOSPC/max_retries; \
> echo 0 > /sys%p/error/metadata/ENODEV/max_retries'"
>
> You also could apply an udevd rule to a specific XFS filesystem by
> UUID filtering:
>
> ACTION=="online", SUBSYSTEM=="xfs", \
> ENV{UUID}=="8f789c27-391f-4bd7-b17d-9bcf2443dc9c", \
> RUN+="/bin/sh -c 'echo 5 > /sys%p/error/metadata/EIO/max_retries'"
>
> Suggested-by: Dave Chinner <david@xxxxxxxxxxxxx>
> Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
> ---
> v2:
> * add UUID property for mount uevent
> * add an udev example for UUID filtering
> v1:
> * http://www.spinics.net/lists/linux-xfs/msg09484.html
> ---
> fs/xfs/xfs_super.c | 29 +++++++++++++++++++++++++++++
> 1 file changed, 29 insertions(+)
>
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 3a3812b4..6f8351c 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -70,6 +70,11 @@ static struct kset *xfs_kset; /* top-level xfs sysfs dir */
> static struct xfs_kobj xfs_dbg_kobj; /* global debug sysfs attrs */
> #endif
>
> +enum {
> + XFS_UEVENT_ENV_CNT = 2,
XFS_UEVENT_MAX_ENV_COUNT ?
> + XFS_UEVENT_UUID_LEN = UUID_STRING_LEN + 6,
> +};
> +
> /*
> * Table driven mount option parser.
> */
> @@ -1530,6 +1535,28 @@ xfs_destroy_percpu_counters(
> percpu_counter_destroy(&mp->m_fdblocks);
> }
>
> +static void
> +xfs_fs_uevent(
> + struct xfs_mount *mp,
> + enum kobject_action action)
> +{
> + int err;
> + char *envp[XFS_UEVENT_ENV_CNT];
> + int i = 0;
> +
> + if (!uuid_is_null(&mp->m_super->s_uuid)) {
> + char uuid[XFS_UEVENT_UUID_LEN];
> +
> + snprintf(uuid, sizeof(uuid), "UUID=%pUb", &mp->m_super->s_uuid);
Should this be "ID_FS_UUID=%pUb" to keep the name consistent with what
blkid injects into the udev environment for block devices?
--D
> + envp[i++] = uuid;
> + }
> + envp[i] = NULL;
> + err = kobject_uevent_env(&mp->m_kobj.kobject, action, envp);
> + if (err)
> + xfs_notice(mp, "Sending XFS uevent %d got error %d",
> + action, err);
> +}
> +
> STATIC int
> xfs_fs_fill_super(
> struct super_block *sb,
> @@ -1667,6 +1694,8 @@ xfs_fs_fill_super(
> goto out_unmount;
> }
>
> + xfs_fs_uevent(mp, KOBJ_ONLINE);
> +
> return 0;
>
> out_filestream_unmount:
> --
> 2.5.0
>
> --
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