1 ====================
2 device-mapper uevent
3 ====================
4
5 The device-mapper uevent code adds the capabil
6 and send kobject uevents (uevents). Previousl
7 available through the ioctl interface. The ad
8 is the event contains environment attributes p
9 the event avoiding the need to query the state
10 the event is received.
11
12 There are two functions currently for device-m
13 listed creates the event and the second functi
14
15 void dm_path_uevent(enum dm_uevent_type even
16 const char *path, unsign
17
18 void dm_send_uevents(struct list_head *event
19
20
21 The variables added to the uevent environment
22
23 Variable Name: DM_TARGET
24 ------------------------
25 :Uevent Action(s): KOBJ_CHANGE
26 :Type: string
27 :Description:
28 :Value: Name of device-mapper target that gene
29
30 Variable Name: DM_ACTION
31 ------------------------
32 :Uevent Action(s): KOBJ_CHANGE
33 :Type: string
34 :Description:
35 :Value: Device-mapper specific action that cau
36 PATH_FAILED - A path has failed;
37 PATH_REINSTATED - A path has been rein
38
39 Variable Name: DM_SEQNUM
40 ------------------------
41 :Uevent Action(s): KOBJ_CHANGE
42 :Type: unsigned integer
43 :Description: A sequence number for this speci
44 :Value: Valid unsigned integer range.
45
46 Variable Name: DM_PATH
47 ----------------------
48 :Uevent Action(s): KOBJ_CHANGE
49 :Type: string
50 :Description: Major and minor number of the pa
51 event.
52 :Value: Path name in the form of "Major:Minor"
53
54 Variable Name: DM_NR_VALID_PATHS
55 --------------------------------
56 :Uevent Action(s): KOBJ_CHANGE
57 :Type: unsigned integer
58 :Description:
59 :Value: Valid unsigned integer range.
60
61 Variable Name: DM_NAME
62 ----------------------
63 :Uevent Action(s): KOBJ_CHANGE
64 :Type: string
65 :Description: Name of the device-mapper device
66 :Value: Name
67
68 Variable Name: DM_UUID
69 ----------------------
70 :Uevent Action(s): KOBJ_CHANGE
71 :Type: string
72 :Description: UUID of the device-mapper device
73 :Value: UUID. (Empty string if there isn't one
74
75 An example of the uevents generated as capture
76 below
77
78 1.) Path failure::
79
80 UEVENT[1192521009.711215] change@/bloc
81 ACTION=change
82 DEVPATH=/block/dm-3
83 SUBSYSTEM=block
84 DM_TARGET=multipath
85 DM_ACTION=PATH_FAILED
86 DM_SEQNUM=1
87 DM_PATH=8:32
88 DM_NR_VALID_PATHS=0
89 DM_NAME=mpath2
90 DM_UUID=mpath-35333333000002328
91 MINOR=3
92 MAJOR=253
93 SEQNUM=1130
94
95 2.) Path reinstate::
96
97 UEVENT[1192521132.989927] change@/bloc
98 ACTION=change
99 DEVPATH=/block/dm-3
100 SUBSYSTEM=block
101 DM_TARGET=multipath
102 DM_ACTION=PATH_REINSTATED
103 DM_SEQNUM=2
104 DM_PATH=8:32
105 DM_NR_VALID_PATHS=1
106 DM_NAME=mpath2
107 DM_UUID=mpath-35333333000002328
108 MINOR=3
109 MAJOR=253
110 SEQNUM=1131
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