[RESEND][PATCH] xfs: add online uevent for mount operation

Hou Tao
2017-08-24T13:37:03Z

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'"

Suggested-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Hou Tao <houtao1@huawei.com>
---
fs/xfs/xfs_super.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 38aaacd..695fe85f 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1530,6 +1530,19 @@ 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;
+
+ err = kobject_uevent(&mp->m_kobj.kobject, action);
+ 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 +1680,8 @@ xfs_fs_fill_super(
goto out_unmount;
}

+ xfs_fs_uevent(mp, KOBJ_ONLINE);
+
return 0;

out_filestream_unmount:
--
2.5.0