On Sep 2 2007 22:20, Josef 'Jeff' Sipek wrote:
>+
>+While rebuilding Unionfs's objects, we also purge any page mappings and
>+truncate inode pages (see fs/Unionfs/dentry.c:purge_inode_data). This is to
fs/unionfs/dentry.c
>+Unionfs maintains the following important invariant regarding mtime's,
>+ctime's, and atime's: the upper inode object's times are the max() of all of
utimes, ctimes and atimes.
>+2. Lockdep (a debugging feature) isn't aware of stacking, and so it
>+ incorrectly complains about locking problems. The problem boils down to
>+ this: Lockdep considers all objects of a certain type to be in the same
>+ class, for example, all inodes. Lockdep doesn't like to see a lock held
>+ on two inodes within the same task, and warns that it could lead to a
>+ deadlock. However, stackable file systems do precisely that: they lock
>+ an upper object, and then a lower object, in a strict order to avoid
>+ locking problems; in addition, Unionfs, as a fan-out file system, may
>+ have to lock several lower inodes. We are currently looking into Lockdep
>+ to see how to make it aware of stackable file systems. In the mean time,
meantime
>@@ -86,5 +86,12 @@ command:
>
> # mount -t unionfs -o remount,incgen none MOUNTPOINT
>
>+Note that the older way of incrementing the generation number using an
>+ioctl, is no longer supported in Unionfs 2.0. Ioctls in general are not
2.1?
Jan
--
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
