Re: Problem report: cannot run nilfs_cleanerd on full filesystem

[dexen deVries <dexen.devries-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Hi,


On Monday 21 of March 2011 12:07:06 you wrote:
> The ".nilfs" file is used for two purposes:
> 
>  1) As the file on which the nilfs library issues ioctls.
> 
>  2) For advisory locks (i.e. fcntl(F_GETLK/F_SETLK/FSETLKW)).  This
>     works as a mutex between the cleaner and other nilfs-tools.
> 
> Note that the nilfs2 kernel code never uses the .nilfs file; it's just
> a regular file for nilfs2.
> 
> As for the item (1), we can use the root directory of each filesystem
> instead.  And for (2), a Posix semaphore or other lock primitives may
> be available.


I tried but failed; it seems Linux doesn't allow opening directory O_RDWR or 
O_WRONLY. And a modyfying ioctl() on directory opened O_RDONLY also returned 
some error, I think it was EBADF. I did not dig any further, so I dunno if 
that's done by kernel's general code or NILFS' ioctl() handler.

I believe nilfs_cleanerd could, on principle, use file descriptor of any file on 
the filesystem in case the user runs into a full fylesystem. Kernel code 
handles that OK, only nilfs_cleanerd would need an extra argument to open a 
different file. What's your oppinion on that?


Regards,
-- 
dexen deVries

[[[↓][→]]]

``In other news, STFU and hack.''
mahmud, in response to Erann Gat's ``How I lost my faith in Lisp''
http://news.ycombinator.com/item?id=2308816
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