Re: [PATCH v2] ext4: add sysfs entry showing whether the fs contains errors

["Lukáš Czerner" <lczerner@redhat.com>]

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On Wed, 7 May 2014, Theodore Ts'o wrote:

> Date: Wed, 7 May 2014 12:01:52 -0400
> From: Theodore Ts'o <tytso@mit.edu>
> To: Lukáš Czerner <lczerner@redhat.com>
> Cc: linux-ext4@vger.kernel.org
> Subject: Re: [PATCH v2] ext4: add sysfs entry showing whether the fs contains
>     errors
> 
> On Wed, May 07, 2014 at 05:35:54PM +0200, Lukáš Czerner wrote:
> > 
> > I tried to find sysfs guidelines but I can not see any in
> > Documentation speaking about the contents of the files.
> > 
> > What are the guidelines then ?
> 
> Documentation/filesystems/sysfs.txt:
> 
>    Attributes can be exported for kobjects in the form of regular
>    files in the filesystem. Sysfs forwards file I/O operations to
>    methods defined for the attributes, providing a means to read and
>    write kernel attributes.
> 
>    Attributes should be ASCII text files, preferably with only one value
>    per file. It is noted that it may not be efficient to contain only one
>    value per file, so it is socially acceptable to express an array of
>    values of the same type. 
> 
> I don't remember that last sentence; it was apparently added since the
> last time I've looked at it.  Originally, the requirement that each
> sysfs file (which was supposed to be an kobject attribute) was
> required to be a single value.  Now there's an escape hatch for
> "efficiency", which is nice....

Perfect, thanks!
-Lukas

> 
> > So you're suggesting to have three sysfs files ?
> > 
> > errors_count
> > first_error_time
> > last_error_time
> 
> Yes, that's what I was suggesting.
> 
> 						- Ted
>