linux-kernel - [RFC PATCH 3/7] exfat: reuse cache to improve exfat_get

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Message-ID: <20251118082208.1034186-4-chizhiling@163.com>
Date: Tue, 18 Nov 2025 16:22:04 +0800
From: Chi Zhiling <chizhiling@....com>
To: linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Alexander Viro <viro@...iv.linux.org.uk>,
	Christian Brauner <brauner@...nel.org>,
	Jan Kara <jack@...e.cz>,
	Matthew Wilcox <willy@...radead.org>,
	Namjae Jeon <linkinjeon@...nel.org>,
	Sungjong Seo <sj1557.seo@...sung.com>,
	Yuezhang Mo <yuezhang.mo@...y.com>,
	Chi Zhiling <chizhiling@...inos.cn>
Subject: [RFC PATCH 3/7] exfat: reuse cache to improve exfat_get_cluster

From: Chi Zhiling <chizhiling@...inos.cn>

Since exfat_ent_get supports cache buffer head, we can use this option to
reduce sb_bread calls when fetching consecutive entries.

Signed-off-by: Chi Zhiling <chizhiling@...inos.cn>
---
 fs/exfat/cache.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/fs/exfat/cache.c b/fs/exfat/cache.c
index 61af3fa05ab7..a5e6858e5a20 100644
--- a/fs/exfat/cache.c
+++ b/fs/exfat/cache.c
@@ -241,6 +241,7 @@ int exfat_get_cluster(struct inode *inode, unsigned int cluster,
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
 	unsigned int limit = sbi->num_clusters;
 	struct exfat_inode_info *ei = EXFAT_I(inode);
+	struct buffer_head *bh = NULL;
 	struct exfat_cache_id cid;
 	unsigned int content;
 
@@ -284,10 +285,10 @@ int exfat_get_cluster(struct inode *inode, unsigned int cluster,
 			exfat_fs_error(sb,
 				"detected the cluster chain loop (i_pos %u)",
 				(*fclus));
-			return -EIO;
+			goto err;
 		}
 
-		if (exfat_ent_get(sb, *dclus, &content, NULL))
+		if (exfat_ent_get(sb, *dclus, &content, &bh))
 			return -EIO;
 
 		*last_dclus = *dclus;
@@ -299,7 +300,7 @@ int exfat_get_cluster(struct inode *inode, unsigned int cluster,
 				exfat_fs_error(sb,
 				       "invalid cluster chain (i_pos %u, last_clus 0x%08x is EOF)",
 				       *fclus, (*last_dclus));
-				return -EIO;
+				goto err;
 			}
 
 			break;
@@ -309,6 +310,10 @@ int exfat_get_cluster(struct inode *inode, unsigned int cluster,
 			cache_init(&cid, *fclus, *dclus);
 	}
 
+	brelse(bh);
 	exfat_cache_add(inode, &cid);
 	return 0;
+err:
+	brelse(bh);
+	return -EIO;
 }
-- 
2.43.0