[PATCH v4 2/4] fs: relocate and tidy up ihold()

[Mateusz Guzik <mjguzik@gmail.com>]

The placement was illogical, move it next to igrab().

Take this opportunity to add docs and an assert on the refcount. While
its modification remains gated with a WARN_ON, the new assert will also
dump the inode state which might aid debugging.

No functional changes.

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
---
 fs/inode.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c
index 1f5a383ccf27..e397a4b56671 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -522,15 +522,6 @@ static void init_once(void *foo)
 	inode_init_once(inode);
 }
 
-/*
- * get additional reference to inode; caller must already hold one.
- */
-void ihold(struct inode *inode)
-{
-	WARN_ON(atomic_inc_return(&inode->i_count) < 2);
-}
-EXPORT_SYMBOL(ihold);
-
 struct wait_queue_head *inode_bit_waitqueue(struct wait_bit_queue_entry *wqe,
 					    struct inode *inode, u32 bit)
 {
@@ -1578,6 +1569,17 @@ ino_t iunique(struct super_block *sb, ino_t max_reserved)
 }
 EXPORT_SYMBOL(iunique);
 
+/**
+ * ihold - get a reference on the inode, provided you already have one
+ * @inode:	inode to operate on
+ */
+void ihold(struct inode *inode)
+{
+	VFS_BUG_ON_INODE(icount_read_once(inode) < 1, inode);
+	WARN_ON(atomic_inc_return(&inode->i_count) < 2);
+}
+EXPORT_SYMBOL(ihold);
+
 struct inode *igrab(struct inode *inode)
 {
 	spin_lock(&inode->i_lock);
-- 
2.48.1