diff options
Diffstat (limited to 'Documentation/filesystems/gfs2-uevents.txt')
| -rw-r--r-- | Documentation/filesystems/gfs2-uevents.txt | 100 |
1 files changed, 0 insertions, 100 deletions
diff --git a/Documentation/filesystems/gfs2-uevents.txt b/Documentation/filesystems/gfs2-uevents.txt deleted file mode 100644 index 19a19ebebc34..000000000000 --- a/Documentation/filesystems/gfs2-uevents.txt +++ /dev/null @@ -1,100 +0,0 @@ - uevents and GFS2 - ================== - -During the lifetime of a GFS2 mount, a number of uevents are generated. -This document explains what the events are and what they are used -for (by gfs_controld in gfs2-utils). - -A list of GFS2 uevents ------------------------ - -1. ADD - -The ADD event occurs at mount time. It will always be the first -uevent generated by the newly created filesystem. If the mount -is successful, an ONLINE uevent will follow. If it is not successful -then a REMOVE uevent will follow. - -The ADD uevent has two environment variables: SPECTATOR=[0|1] -and RDONLY=[0|1] that specify the spectator status (a read-only mount -with no journal assigned), and read-only (with journal assigned) status -of the filesystem respectively. - -2. ONLINE - -The ONLINE uevent is generated after a successful mount or remount. It -has the same environment variables as the ADD uevent. The ONLINE -uevent, along with the two environment variables for spectator and -RDONLY are a relatively recent addition (2.6.32-rc+) and will not -be generated by older kernels. - -3. CHANGE - -The CHANGE uevent is used in two places. One is when reporting the -successful mount of the filesystem by the first node (FIRSTMOUNT=Done). -This is used as a signal by gfs_controld that it is then ok for other -nodes in the cluster to mount the filesystem. - -The other CHANGE uevent is used to inform of the completion -of journal recovery for one of the filesystems journals. It has -two environment variables, JID= which specifies the journal id which -has just been recovered, and RECOVERY=[Done|Failed] to indicate the -success (or otherwise) of the operation. These uevents are generated -for every journal recovered, whether it is during the initial mount -process or as the result of gfs_controld requesting a specific journal -recovery via the /sys/fs/gfs2/<fsname>/lock_module/recovery file. - -Because the CHANGE uevent was used (in early versions of gfs_controld) -without checking the environment variables to discover the state, we -cannot add any more functions to it without running the risk of -someone using an older version of the user tools and breaking their -cluster. For this reason the ONLINE uevent was used when adding a new -uevent for a successful mount or remount. - -4. OFFLINE - -The OFFLINE uevent is only generated due to filesystem errors and is used -as part of the "withdraw" mechanism. Currently this doesn't give any -information about what the error is, which is something that needs to -be fixed. - -5. REMOVE - -The REMOVE uevent is generated at the end of an unsuccessful mount -or at the end of a umount of the filesystem. All REMOVE uevents will -have been preceded by at least an ADD uevent for the same filesystem, -and unlike the other uevents is generated automatically by the kernel's -kobject subsystem. - - -Information common to all GFS2 uevents (uevent environment variables) ----------------------------------------------------------------------- - -1. LOCKTABLE= - -The LOCKTABLE is a string, as supplied on the mount command -line (locktable=) or via fstab. It is used as a filesystem label -as well as providing the information for a lock_dlm mount to be -able to join the cluster. - -2. LOCKPROTO= - -The LOCKPROTO is a string, and its value depends on what is set -on the mount command line, or via fstab. It will be either -lock_nolock or lock_dlm. In the future other lock managers -may be supported. - -3. JOURNALID= - -If a journal is in use by the filesystem (journals are not -assigned for spectator mounts) then this will give the -numeric journal id in all GFS2 uevents. - -4. UUID= - -With recent versions of gfs2-utils, mkfs.gfs2 writes a UUID -into the filesystem superblock. If it exists, this will -be included in every uevent relating to the filesystem. - - - |