xfs: allow assigning the tail lsn with the AIL lock held
Provide a variant of xlog_assign_tail_lsn that has the AIL lock already
held. By doing so we do an additional atomic_read + atomic_set under
the lock, which comes down to two instructions.
Switch xfs_trans_ail_update_bulk and xfs_trans_ail_delete_bulk to the
new version to reduce the number of lock roundtrips, and prepare for
a new addition that would require a third lock roundtrip in
xfs_trans_ail_delete_bulk. This addition is also the reason for
slightly rearranging the conditionals and relying on xfs_log_space_wake
for checking that the filesystem has been shut down internally.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
diff --git a/fs/xfs/xfs_trans_priv.h b/fs/xfs/xfs_trans_priv.h
index 8ab2ced..46a1ebd 100644
--- a/fs/xfs/xfs_trans_priv.h
+++ b/fs/xfs/xfs_trans_priv.h
@@ -102,6 +102,7 @@
void xfs_ail_push(struct xfs_ail *, xfs_lsn_t);
void xfs_ail_push_all(struct xfs_ail *);
+struct xfs_log_item *xfs_ail_min(struct xfs_ail *ailp);
xfs_lsn_t xfs_ail_min_lsn(struct xfs_ail *ailp);
struct xfs_log_item * xfs_trans_ail_cursor_first(struct xfs_ail *ailp,