[PATCH] block: rbd: update sysfs interface

From: Aishwarya Pant
Date: Tue Feb 20 2018 - 04:09:15 EST

The existing sysfs interface has been updated to be in the same format
as described in Documentation/ABI/README. This will be useful for
scripting and tracking changes in the ABI. Attributes have been grouped
by functionality and/or the date on which they were added.

There are a couple of more changes:
- The attributes have been annotated with file permissions RO/RW/WO.
- Added description of the bus attribute supported_features

Signed-off-by: Aishwarya Pant <aishpant@xxxxxxxxx>
---
Documentation/ABI/testing/sysfs-bus-rbd | 202 +++++++++++++++++++-------------
1 file changed, 122 insertions(+), 80 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-rbd b/Documentation/ABI/testing/sysfs-bus-rbd
index f208ac58d613..9549e9b0fcf8 100644
--- a/Documentation/ABI/testing/sysfs-bus-rbd
+++ b/Documentation/ABI/testing/sysfs-bus-rbd
@@ -1,121 +1,163 @@
-What: /sys/bus/rbd/
-Date: November 2010
+What: /sys/bus/rbd/add
+What: /sys/bus/rbd/remove
+Date: Jan, 2012
+KernelVersion: v3.10
Contact: Yehuda Sadeh <yehuda@xxxxxxxxxxxx>,
Sage Weil <sage@xxxxxxxxxxxx>
Description:
+ add : (WO) Add rbd block device.

-Being used for adding and removing rbd block devices.
+ Usage: <mon ip addr> <options> <pool name> <rbd image name> [<snap name>]

-Usage: <mon ip addr> <options> <pool name> <rbd image name> [<snap name>]
+ $ echo "192.168.0.1 name=admin rbd foo" > /sys/bus/rbd/add

- $ echo "192.168.0.1 name=admin rbd foo" > /sys/bus/rbd/add
+ The snapshot name can be "-" or omitted to map the image
+ read/write. A <dev-id> will be assigned for any registered block
+ device. If snapshot is used, it will be mapped read-only.

-The snapshot name can be "-" or omitted to map the image read/write. A <dev-id>
-will be assigned for any registered block device. If snapshot is used, it will
-be mapped read-only.
+ remove: (WO) Remove rbd block device.

-Usage: <dev-id> [force]
+ Usage: <dev-id> [force]

- $ echo 2 > /sys/bus/rbd/remove
+ $ echo 2 > /sys/bus/rbd/remove
+
+ Optional "force" argument which when passed will wait for
+ running requests and then unmap the image. Requests sent to the
+ driver after initiating the removal will be failed. (August
+ 2016, since 4.9.)

-Optional "force" argument which when passed will wait for running requests and
-then unmap the image. Requests sent to the driver after initiating the removal
-will be failed. (August 2016, since 4.9.)

What: /sys/bus/rbd/add_single_major
-Date: December 2013
-KernelVersion: 3.14
-Contact: Sage Weil <sage@xxxxxxxxxxx>
-Description: Available only if rbd module is inserted with single_major
+Date: Dec, 2013
+KernelVersion: v3.14
+Contact: Yehuda Sadeh <yehuda@xxxxxxxxxxxx>,
+ Sage Weil <sage@xxxxxxxxxxxx>
+Description:
+ (WO) Available only if rbd module is inserted with single_major
parameter set to true.
- Usage is the same as for /sys/bus/rbd/add. If present,
+
+ Usage is the same as for /sys/bus/rbd/add. If present, this
should be used instead of the latter: any attempts to use
- /sys/bus/rbd/add if /sys/bus/rbd/add_single_major is
- available will fail for backwards compatibility reasons.
+ /sys/bus/rbd/add if /sys/bus/rbd/add_single_major is available
+ will fail for backwards compatibility reasons.
+

What: /sys/bus/rbd/remove_single_major
-Date: December 2013
-KernelVersion: 3.14
-Contact: Sage Weil <sage@xxxxxxxxxxx>
-Description: Available only if rbd module is inserted with single_major
+Date: Dec, 2013
+KernelVersion: v3.14
+Contact: Yehuda Sadeh <yehuda@xxxxxxxxxxxx>,
+ Sage Weil <sage@xxxxxxxxxxxx>
+Description:
+ (WO) Available only if rbd module is inserted with single_major
parameter set to true.
- Usage is the same as for /sys/bus/rbd/remove. If present,
+
+ Usage is the same as for /sys/bus/rbd/remove. If present, this
should be used instead of the latter: any attempts to use
/sys/bus/rbd/remove if /sys/bus/rbd/remove_single_major is
available will fail for backwards compatibility reasons.

-Entries under /sys/bus/rbd/devices/<dev-id>/
---------------------------------------------
-
-client_addr
-
- The ceph unique client entity_addr_t (address + nonce).
- The format is <address>:<port>/<nonce>: '1.2.3.4:1234/5678' or
- '[1:2:3:4:5:6:7:8]:1234/5678'. (August 2016, since 4.9.)
-
-client_id
-
- The ceph unique client id that was assigned for this specific session.
-
-cluster_fsid
-
- The ceph cluster UUID. (August 2016, since 4.9.)
-
-config_info
-
- The string written into /sys/bus/rbd/add{,_single_major}. (August
- 2016, since 4.9.)
-
-features
-
- A hexadecimal encoding of the feature bits for this image.

-major
-
- The block device major number.
-
-minor
+What: /sys/bus/rbd/supported_features
+Date: Mar, 2017
+KernelVersion: v4.11
+Contact: Yehuda Sadeh <yehuda@xxxxxxxxxxxx>,
+ Sage Weil <sage@xxxxxxxxxxxx>
+Description:
+ (RO) Displays the features supported by the client software
+ implementation so that userspace can generate meaningful error
+ messages and spell out unsupported features that need to be
+ disabled.
+
+
+What: /sys/bus/rbd/devices/<dev-id>/size
+What: /sys/bus/rbd/devices/<dev-id>/refresh
+What: /sys/bus/rbd/devices/<dev-id>/current_snap
+What: /sys/bus/rbd/devices/<dev-id>/name
+What: /sys/bus/rbd/devices/<dev-id>/major
+What: /sys/bus/rbd/devices/<dev-id>/client_id
+Date: Aug, 2010
+KernelVersion: v2.6.37
+Contact: Yehuda Sadeh <yehuda@xxxxxxxxxxxx>,
+ Sage Weil <sage@xxxxxxxxxxxx>
+Description:
+ size: (RO) The size (in bytes) of the mapped block
+ device.

- The block device minor number. (December 2013, since 3.14.)
+ refresh: (WO) Writing to this file will reread the image
+ header data and set all relevant data structures
+ accordingly.

-name
+ current_snap: (RO) The current snapshot for which the device
+ is mapped.

- The name of the rbd image.
+ name: (RO) The name of the rbd image.

-image_id
+ major: (RO) The block device major number.

- The unique id for the rbd image. (For rbd image format 1
- this is empty.)
+ client_id: (RO) The ceph unique client id that was assigned
+ for this specific session.

-pool

- The name of the storage pool where this rbd image resides.
- An rbd image name is unique within its pool.
+What: /sys/bus/rbd/devices/<dev-id>/pool
+What: /sys/bus/rbd/devices/<dev-id>/image_id
+What: /sys/bus/rbd/devices/<dev-id>/features
+What: /sys/bus/rbd/devices/<dev-id>/pool_id
+Date: Jul, 2012
+KernelVersion: v3.10
+Contact: Yehuda Sadeh <yehuda@xxxxxxxxxxxx>,
+ Sage Weil <sage@xxxxxxxxxxxx>
+Description:
+ pool: (RO) The name of the storage pool where this rbd
+ image resides. An rbd image name is unique
+ within its pool.

-pool_id
+ image_id: (WO) The unique id for the rbd image. (For rbd
+ image format 1 this is empty.)

- The unique identifier for the rbd image's pool. This is
- a permanent attribute of the pool. A pool's id will never
- change.
+ features: (RO) A hexadecimal encoding of the feature bits
+ for this image.

-size
+ pool_idr: (RO) The unique identifier for the rbd image's
+ pool. This is a permanent attribute of the pool.
+ A pool's id will never change.

- The size (in bytes) of the mapped block device.

-refresh
+What: /sys/bus/rbd/devices/<dev-id>/parent
+Date: Oct, 2012
+KernelVersion: v3.10
+Contact: Yehuda Sadeh <yehuda@xxxxxxxxxxxx>,
+ Sage Weil <sage@xxxxxxxxxxxx>
+Description:
+ (RO) Information identifying the chain of parent images in a
+ layered rbd image. Entries are separated by empty lines.

- Writing to this file will reread the image header data and set
- all relevant datastructures accordingly.

-current_snap
+What: /sys/bus/rbd/devices/<dev-id>/minor
+Date: Dec, 2013
+KernelVersion: v3.14
+Contact: Yehuda Sadeh <yehuda@xxxxxxxxxxxx>,
+ Sage Weil <sage@xxxxxxxxxxxx>
+Description:
+ (RO) The block device minor number.

- The current snapshot for which the device is mapped.

-snap_id
+What: /sys/bus/rbd/devices/<dev-id>/snap_id
+What: /sys/bus/rbd/devices/<dev-id>/config_info
+What: /sys/bus/rbd/devices/<dev-id>/cluster_fsid
+What: /sys/bus/rbd/devices/<dev-id>/client_addr
+Date: Aug, 2016
+KernelVersion: v4.9
+Contact: Yehuda Sadeh <yehuda@xxxxxxxxxxxx>,
+ Sage Weil <sage@xxxxxxxxxxxx>
+Description:
+ snap_id: (RO) The current snapshot's id.

- The current snapshot's id. (August 2016, since 4.9.)
+ config_info: (RO) The string written into
+ /sys/bus/rbd/add{,_single_major}.

-parent
+ cluster_fsid: (RO) The ceph cluster UUID.

- Information identifying the chain of parent images in a layered rbd
- image. Entries are separated by empty lines.
+ client_addr: (RO) The ceph unique client
+ entity_addr_t (address + nonce). The format is
+ <address>:<port>/<nonce>: '1.2.3.4:1234/5678' or
+ '[1:2:3:4:5:6:7:8]:1234/5678'.
--
2.16.1