linux-kernel - [PATCH 6.6 23/28] libfs: Define a minimum directory offset

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Message-Id: <20241024132225.2271667-8-yukuai1@huaweicloud.com>
Date: Thu, 24 Oct 2024 21:22:20 +0800
From: Yu Kuai <yukuai1@...weicloud.com>
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Subject: [PATCH 6.6 23/28] libfs: Define a minimum directory offset

From: Chuck Lever <chuck.lever@...cle.com>

commit 7beea725a8ca412c6190090ce7c3a13b169592a1 upstream.

This value is used in several places, so make it a symbolic
constant.

Reviewed-by: Jan Kara <jack@...e.cz>
Signed-off-by: Chuck Lever <chuck.lever@...cle.com>
Link: https://lore.kernel.org/r/170820142741.6328.12428356024575347885.stgit@91.116.238.104.host.secureserver.net
Signed-off-by: Christian Brauner <brauner@...nel.org>
Signed-off-by: Yu Kuai <yukuai3@...wei.com>
---
 fs/libfs.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/fs/libfs.c b/fs/libfs.c
index 430f7c95336c..c3dc58e776f9 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -239,6 +239,11 @@ const struct inode_operations simple_dir_inode_operations = {
 };
 EXPORT_SYMBOL(simple_dir_inode_operations);
 
+/* 0 is '.', 1 is '..', so always start with offset 2 or more */
+enum {
+	DIR_OFFSET_MIN	= 2,
+};
+
 static void offset_set(struct dentry *dentry, u32 offset)
 {
 	dentry->d_fsdata = (void *)((uintptr_t)(offset));
@@ -260,9 +265,7 @@ void simple_offset_init(struct offset_ctx *octx)
 {
 	xa_init_flags(&octx->xa, XA_FLAGS_ALLOC1);
 	lockdep_set_class(&octx->xa.xa_lock, &simple_offset_xa_lock);
-
-	/* 0 is '.', 1 is '..', so always start with offset 2 */
-	octx->next_offset = 2;
+	octx->next_offset = DIR_OFFSET_MIN;
 }
 
 /**
@@ -275,7 +278,7 @@ void simple_offset_init(struct offset_ctx *octx)
  */
 int simple_offset_add(struct offset_ctx *octx, struct dentry *dentry)
 {
-	static const struct xa_limit limit = XA_LIMIT(2, U32_MAX);
+	static const struct xa_limit limit = XA_LIMIT(DIR_OFFSET_MIN, U32_MAX);
 	u32 offset;
 	int ret;
 
@@ -480,7 +483,7 @@ static int offset_readdir(struct file *file, struct dir_context *ctx)
 		return 0;
 
 	/* In this case, ->private_data is protected by f_pos_lock */
-	if (ctx->pos == 2)
+	if (ctx->pos == DIR_OFFSET_MIN)
 		file->private_data = NULL;
 	else if (file->private_data == ERR_PTR(-ENOENT))
 		return 0;
-- 
2.39.2