Messages in this thread | | | Date | Fri, 13 Mar 2015 11:05:22 -0400 | From | Theodore Ts'o <> | Subject | Re: [RFC] ext4: Add pollable sysfs entry for block threshold events |
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On Wed, Mar 11, 2015 at 03:12:25PM +0100, Lukáš Czerner wrote: > > I though you were advocating for a solution independent on the file > system. This is ext4 only solution, but I do not really have > anything against this.
It would be nice if we could have a fs-independent solution so that we don't have to support the ext4-specific interface forever. If we had the thresholds set in struct super, and the file system were to call a function defined in struct super_operations when the file system has gotten too full, this wouldn't be all that hard.
The main issue is what is the proper generic way of notifying userspace. Using a pollable sysfs file is one way, although problem with that is we don't yet have a standardized place to locate where, given a particular mounted file system / block device, where to find its hierarchy in the sysfs tree. Right now we have /sys/fs/<type>/... but that's owned by the file system and so it get's a bit tricky to do something generic.
Other solutions might be to report file system full (and file system corruption issues, etc.) via a netlink socket, or if we want to do things in a systemd-complaint way, we could use the kernel-level dbus approach which Greg K-H and company are pushing. :-)
- Ted
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