linux-ext4 - [PATCH v3 06/10] libfs: Add helper to choose dentry operations at mount

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Message-ID: <20240119184742.31088-7-krisman@suse.de>
Date: Fri, 19 Jan 2024 15:47:38 -0300
From: Gabriel Krisman Bertazi <krisman@...e.de>
To: viro@...iv.linux.org.uk,
	ebiggers@...nel.org,
	jaegeuk@...nel.org,
	tytso@....edu
Cc: linux-ext4@...r.kernel.org,
	linux-f2fs-devel@...ts.sourceforge.net,
	linux-fsdevel@...r.kernel.org,
	amir73il@...il.com,
	Gabriel Krisman Bertazi <krisman@...e.de>
Subject: [PATCH v3 06/10] libfs: Add helper to choose dentry operations at mount

In preparation to drop the similar helper that sets d_op at lookup time,
add a version to set the right d_op filesystem-wide, through sb->s_d_op.
The operations structures are shared across filesystems supporting
fscrypt and/or casefolding, therefore we can keep it in common libfs
code.

Signed-off-by: Gabriel Krisman Bertazi <krisman@...e.de>
---
 fs/libfs.c         | 29 +++++++++++++++++++++++++++++
 include/linux/fs.h |  1 +
 2 files changed, 30 insertions(+)

diff --git a/fs/libfs.c b/fs/libfs.c
index c4be0961faf0..9cd4df6969d2 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -1822,6 +1822,35 @@ void generic_set_encrypted_ci_d_ops(struct dentry *dentry)
 }
 EXPORT_SYMBOL(generic_set_encrypted_ci_d_ops);
 
+/**
+ * generic_set_sb_d_ops - helper for choosing the set of
+ * filesystem-wide dentry operations for the enabled features
+ * @sb: superblock to be configured
+ *
+ * Filesystems supporting casefolding and/or fscrypt can call this
+ * helper at mount-time to configure sb->s_d_root to best set of dentry
+ * operations required for the enabled features. The helper must be
+ * called after these have been configured, but before the root
+ * dentry is created.
+ *
+ */
+void generic_set_sb_d_ops(struct super_block *sb)
+{
+#if IS_ENABLED(CONFIG_UNICODE)
+	if (sb->s_encoding) {
+		sb->s_d_op = &generic_ci_dentry_ops;
+		return;
+	}
+#endif
+#ifdef CONFIG_FS_ENCRYPTION
+	if (sb->s_cop) {
+		sb->s_d_op = &generic_encrypted_dentry_ops;
+		return;
+	}
+#endif
+}
+EXPORT_SYMBOL(generic_set_sb_d_ops);
+
 /**
  * inode_maybe_inc_iversion - increments i_version
  * @inode: inode with the i_version that should be updated
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e6667ece5e64..c985d9392b61 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3202,6 +3202,7 @@ extern int generic_file_fsync(struct file *, loff_t, loff_t, int);
 extern int generic_check_addressable(unsigned, u64);
 
 extern void generic_set_encrypted_ci_d_ops(struct dentry *dentry);
+extern void generic_set_sb_d_ops(struct super_block *sb);
 
 static inline bool sb_has_encoding(const struct super_block *sb)
 {
-- 
2.43.0