linux-kernel - [PATCH bpf-next v3 1/4] libfs: move shmem_exchange to simple_rename

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Date:   Thu, 28 Oct 2021 10:47:21 +0100
From:   Lorenz Bauer <lmb@...udflare.com>
To:     viro@...iv.linux.org.uk, Hugh Dickins <hughd@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>
Cc:     mszeredi@...hat.com, gregkh@...uxfoundation.org,
        Lorenz Bauer <lmb@...udflare.com>,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, netdev@...r.kernel.org, bpf@...r.kernel.org
Subject: [PATCH bpf-next v3 1/4] libfs: move shmem_exchange to simple_rename_exchange

Move shmem_exchange and make it available to other callers.

Suggested-by: <mszeredi@...hat.com>
Signed-off-by: Lorenz Bauer <lmb@...udflare.com>
---
 fs/libfs.c         | 24 ++++++++++++++++++++++++
 include/linux/fs.h |  2 ++
 mm/shmem.c         | 24 +-----------------------
 3 files changed, 27 insertions(+), 23 deletions(-)

diff --git a/fs/libfs.c b/fs/libfs.c
index 51b4de3b3447..1cf144dc9ed2 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -448,6 +448,30 @@ int simple_rmdir(struct inode *dir, struct dentry *dentry)
 }
 EXPORT_SYMBOL(simple_rmdir);
 
+int simple_rename_exchange(struct inode *old_dir, struct dentry *old_dentry,
+			   struct inode *new_dir, struct dentry *new_dentry)
+{
+	bool old_is_dir = d_is_dir(old_dentry);
+	bool new_is_dir = d_is_dir(new_dentry);
+
+	if (old_dir != new_dir && old_is_dir != new_is_dir) {
+		if (old_is_dir) {
+			drop_nlink(old_dir);
+			inc_nlink(new_dir);
+		} else {
+			drop_nlink(new_dir);
+			inc_nlink(old_dir);
+		}
+	}
+	old_dir->i_ctime = old_dir->i_mtime =
+	new_dir->i_ctime = new_dir->i_mtime =
+	d_inode(old_dentry)->i_ctime =
+	d_inode(new_dentry)->i_ctime = current_time(old_dir);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(simple_rename_exchange);
+
 int simple_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
 		  struct dentry *old_dentry, struct inode *new_dir,
 		  struct dentry *new_dentry, unsigned int flags)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e7a633353fd2..333b8af405ce 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3383,6 +3383,8 @@ extern int simple_open(struct inode *inode, struct file *file);
 extern int simple_link(struct dentry *, struct inode *, struct dentry *);
 extern int simple_unlink(struct inode *, struct dentry *);
 extern int simple_rmdir(struct inode *, struct dentry *);
+extern int simple_rename_exchange(struct inode *old_dir, struct dentry *old_dentry,
+				  struct inode *new_dir, struct dentry *new_dentry);
 extern int simple_rename(struct user_namespace *, struct inode *,
 			 struct dentry *, struct inode *, struct dentry *,
 			 unsigned int);
diff --git a/mm/shmem.c b/mm/shmem.c
index b5860f4a2738..a18dde3d3092 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2945,28 +2945,6 @@ static int shmem_rmdir(struct inode *dir, struct dentry *dentry)
 	return shmem_unlink(dir, dentry);
 }
 
-static int shmem_exchange(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry)
-{
-	bool old_is_dir = d_is_dir(old_dentry);
-	bool new_is_dir = d_is_dir(new_dentry);
-
-	if (old_dir != new_dir && old_is_dir != new_is_dir) {
-		if (old_is_dir) {
-			drop_nlink(old_dir);
-			inc_nlink(new_dir);
-		} else {
-			drop_nlink(new_dir);
-			inc_nlink(old_dir);
-		}
-	}
-	old_dir->i_ctime = old_dir->i_mtime =
-	new_dir->i_ctime = new_dir->i_mtime =
-	d_inode(old_dentry)->i_ctime =
-	d_inode(new_dentry)->i_ctime = current_time(old_dir);
-
-	return 0;
-}
-
 static int shmem_whiteout(struct user_namespace *mnt_userns,
 			  struct inode *old_dir, struct dentry *old_dentry)
 {
@@ -3012,7 +2990,7 @@ static int shmem_rename2(struct user_namespace *mnt_userns,
 		return -EINVAL;
 
 	if (flags & RENAME_EXCHANGE)
-		return shmem_exchange(old_dir, old_dentry, new_dir, new_dentry);
+		return simple_rename_exchange(old_dir, old_dentry, new_dir, new_dentry);
 
 	if (!simple_empty(new_dentry))
 		return -ENOTEMPTY;
-- 
2.32.0