[PATCH RFC v2 17/28] filelock: add an inode_lease_ignore_mask helper

[Jeff Layton]

Add a new routine that returns a mask of all dir change events that are
currently ignored by any leases. nfsd will use this to determine how to
configure the fsnotify_mark mask.

Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
 fs/locks.c               | 32 ++++++++++++++++++++++++++++++++
 include/linux/filelock.h |  1 +
 2 files changed, 33 insertions(+)

diff --git a/fs/locks.c b/fs/locks.c
index 95270a1fab4a1792a6fcad738cc9d937d99ad2af..522455196353f64d3150c45c9d1cd260751bd7b9 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1526,6 +1526,38 @@ any_leases_conflict(struct inode *inode, struct file_lease *breaker)
 	return false;
 }
 
+#define IGNORE_MASK	(FL_IGN_DIR_CREATE | FL_IGN_DIR_DELETE | FL_IGN_DIR_RENAME)
+
+/**
+ * inode_lease_ignore_mask - return union of all ignored inode events for this inode
+ * @inode: inode of which to get ignore mask
+ *
+ * Walk the list of leases, and return the result of all of
+ * their FL_IGN_DIR_* bits or'ed together.
+ */
+u32
+inode_lease_ignore_mask(struct inode *inode)
+{
+	struct file_lock_context *ctx;
+	struct file_lock_core *flc;
+	u32 mask = 0;
+
+	ctx = locks_inode_context(inode);
+	if (!ctx)
+		return 0;
+
+	spin_lock(&ctx->flc_lock);
+	list_for_each_entry(flc, &ctx->flc_lease, flc_list) {
+		mask |= flc->flc_flags & IGNORE_MASK;
+		/* If we already have everything, we can stop */
+		if (mask == IGNORE_MASK)
+			break;
+	}
+	spin_unlock(&ctx->flc_lock);
+	return mask;
+}
+EXPORT_SYMBOL_GPL(inode_lease_ignore_mask);
+
 static bool
 ignore_dir_deleg_break(struct file_lease *fl, unsigned int flags)
 {
diff --git a/include/linux/filelock.h b/include/linux/filelock.h
index 32b30c14f5fd52727b1a18957e9dbc930c922941..4513a8dad3974bf5fb08e0df4f085d71155e04f5 100644
--- a/include/linux/filelock.h
+++ b/include/linux/filelock.h
@@ -244,6 +244,7 @@ int generic_setlease(struct file *, int, struct file_lease **, void **priv);
 int kernel_setlease(struct file *, int, struct file_lease **, void **);
 int vfs_setlease(struct file *, int, struct file_lease **, void **);
 int lease_modify(struct file_lease *, int, struct list_head *);
+u32 inode_lease_ignore_mask(struct inode *inode);
 
 struct notifier_block;
 int lease_register_notifier(struct notifier_block *);

-- 
2.49.0