Dropping of last reference to dentry lock is a complicated operation involving
dropping of reference to inode. This can get complicated and quota code in
particular needs to obtain some quota locks which leads to potential deadlock.
Thus we defer dropping of inode reference to ocfs2_wq.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
The node maps that are set/unset by these votes are no longer relevant, thus
we can remove the mount and umount votes. Since those are the last two
remaining votes, we can also remove the entire vote infrastructure.
The vote thread has been renamed to the downconvert thread, and the small
amount of functionality related to managing it has been moved into
fs/ocfs2/dlmglue.c. All references to votes have been removed or updated.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
The existing bug statement didn't take into account unhashed dentries which
might not have a cluster lock on them. This could happen if a node exporting
the file system via NFS is rebooted, re-exported to nfs clients and then
unmounted. It's fine in this case to not have a dentry cluster lock.
Just remove the bug statement and replace it with an error print, which
does the proper checks. Though we want to know if something has happened
which might have prevented a cluster lock from being created, it's
definitely not necessary to panic the machine for this.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Do this to avoid a theoretical (I haven't seen this in practice) race where
the downconvert thread might drop the dentry lock, allowing a remote unlink
to proceed before dropping the inode locks. This could bounce access to the
orphan dir between nodes.
There doesn't seem to be a need to do the same in ocfs2_dentry_iput() as
that's never called for the last ref drop from the downconvert thread.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Fix the various misspellings of "system", controller", "interrupt" and
"[un]necessary".
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
We can't use LKM_LOCAL for new dentry locks because an unlink and subsequent
re-create of a name/inode pair may result in the lock still being mastered
somewhere in the cluster.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Make use of FS_RENAME_DOES_D_MOVE to avoid a race condition that can occur
during ->rename() if we d_move() outside of the parent directory cluster
locks, and another node discovers the new name (created during the rename)
and unlinks it. d_move() will unconditionally rehash a dentry - which will
leave stale data in the system.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Replace the dentry vote mechanism with a cluster lock which covers a set
of dentries. This allows us to force d_delete() only on nodes which actually
care about an unlink.
Every node that does a ->lookup() gets a read only lock on the dentry, until
an unlink during which the unlinking node, will request an exclusive lock,
forcing the other nodes who care about that dentry to d_delete() it. The
effect is that we retain a very lightweight ->d_revalidate(), and at the
same time get to make large improvements to the average case performance of
the ocfs2 unlink and rename operations.
This patch adds the higher level API and the dentry manipulation code.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Replace the dentry vote mechanism with a cluster lock which covers a set
of dentries. This allows us to force d_delete() only on nodes which actually
care about an unlink.
Every node that does a ->lookup() gets a read only lock on the dentry, until
an unlink during which the unlinking node, will request an exclusive lock,
forcing the other nodes who care about that dentry to d_delete() it. The
effect is that we retain a very lightweight ->d_revalidate(), and at the
same time get to make large improvements to the average case performance of
the ocfs2 unlink and rename operations.
This patch adds the cluster lock type which OCFS2 can attach to
dentries. A small number of fs/ocfs2/dcache.c functions are stubbed
out so that this change can compile.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Al Viro
Jan Kara
Mark Fasheh
Robert P. J. Day