On 04/17/2015 06:08 PM, John Spray wrote: > > On 17/04/2015 16:43, Jan Kara wrote: >> On Fri 17-04-15 15:51:14, John Spray wrote: >>> On 17/04/2015 14:23, Austin S Hemmelgarn wrote: >>> >>>> For some filesystems, it may make sense to differentiate between a >>>> generic warning and an error. For BTRFS and ZFS for example, if >>>> there is a csum error on a block, this will get automatically >>>> corrected in many configurations, and won't require anything like >>>> fsck to be run, but monitoring applications will still probably >>>> want to be notified. >>> Another key differentiation IMHO is between transient errors (like >>> server is unavailable in a distributed filesystem) that will block >>> the filesystem but might clear on their own, vs. permanent errors >>> like unreadable drives that definitely will not clear until the >>> administrator takes some action. It's usually a reasonable >>> approximation to call transient issues warnings, and permanent >>> issues errors. >> So you can have events like FS_UNAVAILABLE and FS_AVAILABLE but what use >> would this have? I wouldn't like the interface to be dumping ground for >> random crap - we have dmesg for that :). > In that case I'm confused -- why would ENOSPC be an appropriate use of this interface if the mount being entirely blocked would be inappropriate? Isn't being unable to service any I/O a more fundamental and severe thing than being up and healthy but full? > > Were you intending the interface to be exclusively for data integrity issues like checksum failures, rather than more general events about a mount that userspace would probably like to know about? > > John > I think we should support both and leave the decision on what is to be reported or not to particular file systems keeping it to a reasonable extent, of course. The interface should hand it over to user space - acting as a go-between. I would though avoid any filesystem specific events (when it comes to specifying those), keeping it as generic as possible. BR Beata -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
