Track negative dentries by recording the generation number of the parent
directory in d_fsdata. The generation number for the parent directory is
recorded in the inode_info, which increments every time the lock on the
directory is dropped.
If the generation number of the parent directory and the negative dentry
matches, there is no need to perform the revalidate, else a revalidate
is forced. This improves performance in situations where nodes look for
the same non-existent file multiple times.
Thanks Mark for explaining the DLM sequence.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.de>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
In commit ea455f8ab6, we moved the dentry lock
put process into ocfs2_wq. This causes problems during umount because ocfs2_wq
can drop references to inodes while they are being invalidated by
invalidate_inodes() causing all sorts of nasty things (invalidate_inodes()
ending in an infinite loop, "Busy inodes after umount" messages etc.).
We fix the problem by stopping ocfs2_wq from doing any further releasing of
inode references on the superblock being unmounted, wait until it finishes
the current round of releasing and finally cleaning up all the references in
dentry_lock_list from ocfs2_put_super().
The issue was tracked down by Tao Ma <tao.ma@oracle.com>.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
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>
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>
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>
Goldwyn Rodrigues