[PATCH v2 24/54] fs: use inode_tryget in find_inode*

[Josef Bacik <josef@toxicpanda.com>]

Now that we never drop the i_count to 0 for valid objects, rework the
logic in the find_inode* helpers to use inode_tryget() to see if they
have a live inode.  If this fails we can wait for the inode to be freed
as we know it's currently being evicted.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 fs/inode.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c
index 66402786cf8f..4ed2e8ff5334 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1093,6 +1093,7 @@ long prune_icache_sb(struct super_block *sb, struct shrink_control *sc)
 }
 
 static void __wait_on_freeing_inode(struct inode *inode, bool is_inode_hash_locked);
+
 /*
  * Called with the inode lock held.
  */
@@ -1116,16 +1117,15 @@ static struct inode *find_inode(struct super_block *sb,
 		if (!test(inode, data))
 			continue;
 		spin_lock(&inode->i_lock);
-		if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
-			__wait_on_freeing_inode(inode, is_inode_hash_locked);
-			goto repeat;
-		}
 		if (unlikely(inode->i_state & I_CREATING)) {
 			spin_unlock(&inode->i_lock);
 			rcu_read_unlock();
 			return ERR_PTR(-ESTALE);
 		}
-		__iget(inode);
+		if (!inode_tryget(inode)) {
+			__wait_on_freeing_inode(inode, is_inode_hash_locked);
+			goto repeat;
+		}
 		inode_lru_list_del(inode);
 		spin_unlock(&inode->i_lock);
 		rcu_read_unlock();
@@ -1158,16 +1158,15 @@ static struct inode *find_inode_fast(struct super_block *sb,
 		if (inode->i_sb != sb)
 			continue;
 		spin_lock(&inode->i_lock);
-		if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
-			__wait_on_freeing_inode(inode, is_inode_hash_locked);
-			goto repeat;
-		}
 		if (unlikely(inode->i_state & I_CREATING)) {
 			spin_unlock(&inode->i_lock);
 			rcu_read_unlock();
 			return ERR_PTR(-ESTALE);
 		}
-		__iget(inode);
+		if (!inode_tryget(inode)) {
+			__wait_on_freeing_inode(inode, is_inode_hash_locked);
+			goto repeat;
+		}
 		inode_lru_list_del(inode);
 		spin_unlock(&inode->i_lock);
 		rcu_read_unlock();
-- 
2.49.0