linux-kernel - [PATCH 09/15] nilfs2: do not acquire rwsem in nilfs_bmap

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Date: Mon, 22 Jan 2024 23:01:56 +0900
From: Ryusuke Konishi <konishi.ryusuke@...il.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-nilfs@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 09/15] nilfs2: do not acquire rwsem in nilfs_bmap_write()

It is now clear that nilfs_bmap_write() is only used to finalize logs
written to disk.  Concurrent bmap modification operations are not
performed on bmaps in this context.  Additionally, this function does not
modify data used in read-only operations such as bmap lookups.

Therefore, there is no need to acquire bmap->b_sem in nilfs_bmap_write(),
so delete it.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@...il.com>
---
 fs/nilfs2/bmap.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/fs/nilfs2/bmap.c b/fs/nilfs2/bmap.c
index 7a8f166f2c8d..383f0afa2cea 100644
--- a/fs/nilfs2/bmap.c
+++ b/fs/nilfs2/bmap.c
@@ -548,13 +548,10 @@ int nilfs_bmap_read(struct nilfs_bmap *bmap, struct nilfs_inode *raw_inode)
  */
 void nilfs_bmap_write(struct nilfs_bmap *bmap, struct nilfs_inode *raw_inode)
 {
-	down_write(&bmap->b_sem);
 	memcpy(raw_inode->i_bmap, bmap->b_u.u_data,
 	       NILFS_INODE_BMAP_SIZE * sizeof(__le64));
 	if (bmap->b_inode->i_ino == NILFS_DAT_INO)
 		bmap->b_last_allocated_ptr = NILFS_BMAP_NEW_PTR_INIT;
-
-	up_write(&bmap->b_sem);
 }
 
 void nilfs_bmap_init_gc(struct nilfs_bmap *bmap)
-- 
2.34.1