[PATCH 02/20] fs: factor out d_mark_tmpfile()

[Kent Overstreet <kent.overstreet@linux.dev>]

From: Kent Overstreet <kent.overstreet@gmail.com>

New helper for bcachefs - bcachefs doesn't want the
inode_dec_link_count() call that d_tmpfile does, it handles i_nlink on
its own atomically with other btree updates

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: linux-fsdevel@vger.kernel.org
---
 fs/dcache.c            | 12 ++++++++++--
 include/linux/dcache.h |  1 +
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/fs/dcache.c b/fs/dcache.c
index 52e6d5fdab..dbdafa2617 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -3249,11 +3249,10 @@ void d_genocide(struct dentry *parent)
 
 EXPORT_SYMBOL(d_genocide);
 
-void d_tmpfile(struct file *file, struct inode *inode)
+void d_mark_tmpfile(struct file *file, struct inode *inode)
 {
 	struct dentry *dentry = file->f_path.dentry;
 
-	inode_dec_link_count(inode);
 	BUG_ON(dentry->d_name.name != dentry->d_iname ||
 		!hlist_unhashed(&dentry->d_u.d_alias) ||
 		!d_unlinked(dentry));
@@ -3263,6 +3262,15 @@ void d_tmpfile(struct file *file, struct inode *inode)
 				(unsigned long long)inode->i_ino);
 	spin_unlock(&dentry->d_lock);
 	spin_unlock(&dentry->d_parent->d_lock);
+}
+EXPORT_SYMBOL(d_mark_tmpfile);
+
+void d_tmpfile(struct file *file, struct inode *inode)
+{
+	struct dentry *dentry = file->f_path.dentry;
+
+	inode_dec_link_count(inode);
+	d_mark_tmpfile(file, inode);
 	d_instantiate(dentry, inode);
 }
 EXPORT_SYMBOL(d_tmpfile);
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 6b351e009f..3da2f0545d 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -251,6 +251,7 @@ extern struct dentry * d_make_root(struct inode *);
 /* <clickety>-<click> the ramfs-type tree */
 extern void d_genocide(struct dentry *);
 
+extern void d_mark_tmpfile(struct file *, struct inode *);
 extern void d_tmpfile(struct file *, struct inode *);
 
 extern struct dentry *d_find_alias(struct inode *);
-- 
2.40.1