linux-kernel - [PATCH] bcachefs: Change destroy_inode to free

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Date: Fri, 26 Apr 2024 15:29:56 +0800
From: Youling Tang <youling.tang@...ux.dev>
To: Kent Overstreet <kent.overstreet@...ux.dev>
Cc: linux-bcachefs@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Youling Tang <tangyouling@...inos.cn>
Subject: [PATCH] bcachefs: Change destroy_inode to free_inode

From: Youling Tang <tangyouling@...inos.cn>

The vfs[1] documentation describes free_inode as follows:
```
free_inode
    this method is called from RCU callback. If you use call_rcu()
    in ->destroy_inode to free ‘struct inode’ memory, then it’s
    better to release memory in this method.
```

free_inode will be called by the RCU callback, so it might be better
to move the inode free operation to destroy_inode.

Similar to commit ae6b47b5653e ("fs/ntfs3: Change destroy_inode to
free_inode").

Link:
[1]: https://www.kernel.org/doc/html/latest/filesystems/vfs.html

Signed-off-by: Youling Tang <tangyouling@...inos.cn>
---
 fs/bcachefs/fs.c | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c
index afb57ea99431..c82ee192a2e2 100644
--- a/fs/bcachefs/fs.c
+++ b/fs/bcachefs/fs.c
@@ -1511,17 +1511,9 @@ static void bch2_vfs_inode_init(struct btree_trans *trans, subvol_inum inum,
 	mapping_set_large_folios(inode->v.i_mapping);
 }
 
-static void bch2_i_callback(struct rcu_head *head)
+static void bch2_free_inode(struct inode *vinode)
 {
-	struct inode *vinode = container_of(head, struct inode, i_rcu);
-	struct bch_inode_info *inode = to_bch_ei(vinode);
-
-	kmem_cache_free(bch2_inode_cache, inode);
-}
-
-static void bch2_destroy_inode(struct inode *vinode)
-{
-	call_rcu(&vinode->i_rcu, bch2_i_callback);
+	kmem_cache_free(bch2_inode_cache, to_bch_ei(vinode));
 }
 
 static int inode_update_times_fn(struct btree_trans *trans,
@@ -1829,7 +1821,7 @@ static int bch2_unfreeze(struct super_block *sb)
 
 static const struct super_operations bch_super_operations = {
 	.alloc_inode	= bch2_alloc_inode,
-	.destroy_inode	= bch2_destroy_inode,
+	.free_inode	= bch2_free_inode,
 	.write_inode	= bch2_vfs_write_inode,
 	.evict_inode	= bch2_evict_inode,
 	.sync_fs	= bch2_sync_fs,
-- 
2.34.1