From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- Documentation/ABI/testing/sysfs-class-rnbd-client | 133 ++++++++++++++++++++++ 1 file changed, 133 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-rnbd-client (limited to 'Documentation/ABI/testing/sysfs-class-rnbd-client') diff --git a/Documentation/ABI/testing/sysfs-class-rnbd-client b/Documentation/ABI/testing/sysfs-class-rnbd-client new file mode 100644 index 000000000..0b5997ab3 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-rnbd-client @@ -0,0 +1,133 @@ +What: /sys/class/rnbd-client +Date: Feb 2020 +KernelVersion: 5.7 +Contact: Jack Wang Danil Kipnis +Description: Provide information about RNBD-client. + All sysfs files that are not read-only provide the usage information on read: + + Example:: + + # cat /sys/class/rnbd-client/ctl/map_device + + > Usage: echo "sessname= path=<[srcaddr,]dstaddr> + > [path=<[srcaddr,]dstaddr>] device_path= + > [access_mode=] > map_device + > + > addr ::= [ ip: | ip: | gid: ] + +What: /sys/class/rnbd-client/ctl/map_device +Date: Feb 2020 +KernelVersion: 5.7 +Contact: Jack Wang Danil Kipnis +Description: Expected format is the following:: + + sessname= + path=<[srcaddr,]dstaddr> [path=<[srcaddr,]dstaddr> ...] + device_path= + [access_mode=] + + Where: + + sessname: + accepts a string not bigger than 256 chars, which identifies + a given session on the client and on the server. + I.e. "clt_hostname-srv_hostname" could be a natural choice. + + path: + describes a connection between the client and the server by + specifying destination and, when required, the source address. + The addresses are to be provided in the following format:: + + ip: + ip: + gid: + + for example:: + + path=ip:10.0.0.66 + + The single addr is treated as the destination. + The connection will be established to this server from any client IP address. + + :: + + path=ip:10.0.0.66,ip:10.0.1.66 + + First addr is the source address and the second is the destination. + + If multiple "path=" options are specified multiple connection + will be established and data will be sent according to + the selected multipath policy (see RTRS mp_policy sysfs entry description). + + device_path: + Path to the block device on the server side. Path is specified + relative to the directory on server side configured in the + 'dev_search_path' module parameter of the rnbd_server. + The rnbd_server prepends the received from client + with and tries to open the + / block device. On success, + a /dev/rnbd device file, a /sys/block/rnbd/ + directory and an entry in /sys/class/rnbd-client/ctl/devices + will be created. + + If 'dev_search_path' contains '%SESSNAME%', then each session can + have different devices namespace, e.g. server was configured with + the following parameter "dev_search_path=/run/rnbd-devs/%SESSNAME%", + client has this string "sessname=blya device_path=sda", then server + will try to open: /run/rnbd-devs/blya/sda. + + access_mode: + the access_mode parameter specifies if the device is to be + mapped as "ro" read-only or "rw" read-write. The server allows + a device to be exported in rw mode only once. The "migration" + access mode has to be specified if a second mapping in read-write + mode is desired. + + By default "rw" is used. + + nr_poll_queues + specifies the number of poll-mode queues. If the IO has HIPRI flag, + the block-layer will send the IO via the poll-mode queue. + For fast network and device the polling is faster than interrupt-base + IO handling because it saves time for context switching, switching to + another process, handling the interrupt and switching back to the + issuing process. + + Set -1 if you want to set it as the number of CPUs + By default rnbd client creates only irq-mode queues. + + NOTICE: MUST make a unique session for a device using the poll-mode queues. + + Exit Codes: + + If the device is already mapped it will fail with EEXIST. If the input + has an invalid format it will return EINVAL. If the device path cannot + be found on the server, it will fail with ENOENT. + + Finding device file after mapping + --------------------------------- + + After mapping, the device file can be found by: + o The symlink /sys/class/rnbd-client/ctl/devices/@ + points to /sys/block/. The last part of the symlink destination + is the same as the device name. By extracting the last part of the + path the path to the device /dev/ can be build. + + * /dev/block/$(cat /sys/class/rnbd-client/ctl/devices/@/dev) + + How to find the of the device is described on the next + section. + +What: /sys/class/rnbd-client/ctl/devices/ +Date: Feb 2020 +KernelVersion: 5.7 +Contact: Jack Wang Danil Kipnis +Description: For each device mapped on the client a new symbolic link is created as + /sys/class/rnbd-client/ctl/devices/@, which points + to the block device created by rnbd (/sys/block/rnbd/). + The of each device is created as follows: + + - If the 'device_path' provided during mapping contains slashes ("/"), + they are replaced by exclamation mark ("!") and used as as the + . Otherwise, the will be the same as the + "device_path" provided. -- cgit v1.2.3