linux-kernel - [PATCH 5.13 136/156] vboxsf: Honor excl flag to the dir-inode create op

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Date:   Thu, 22 Jul 2021 18:31:51 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Hans de Goede <hdegoede@...hat.com>
Subject: [PATCH 5.13 136/156] vboxsf: Honor excl flag to the dir-inode create op

From: Hans de Goede <hdegoede@...hat.com>

commit cc3ddee97cff034cea4d095de4a484c92a219bf5 upstream.

Honor the excl flag to the dir-inode create op, instead of behaving
as if it is always set.

Note the old behavior still worked most of the time since a non-exclusive
open only calls the create op, if there is a race and the file is created
between the dentry lookup and the calling of the create call.

While at it change the type of the is_dir parameter to the
vboxsf_dir_create() helper from an int to a bool, to be consistent with
the use of bool for the excl parameter.

Fixes: 0fd169576648 ("fs: Add VirtualBox guest shared folder (vboxsf) support")
Signed-off-by: Hans de Goede <hdegoede@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/vboxsf/dir.c |   16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

--- a/fs/vboxsf/dir.c
+++ b/fs/vboxsf/dir.c
@@ -253,7 +253,7 @@ static int vboxsf_dir_instantiate(struct
 }
 
 static int vboxsf_dir_create(struct inode *parent, struct dentry *dentry,
-			     umode_t mode, int is_dir)
+			     umode_t mode, bool is_dir, bool excl)
 {
 	struct vboxsf_inode *sf_parent_i = VBOXSF_I(parent);
 	struct vboxsf_sbi *sbi = VBOXSF_SBI(parent->i_sb);
@@ -261,10 +261,12 @@ static int vboxsf_dir_create(struct inod
 	int err;
 
 	params.handle = SHFL_HANDLE_NIL;
-	params.create_flags = SHFL_CF_ACT_CREATE_IF_NEW |
-			      SHFL_CF_ACT_FAIL_IF_EXISTS |
-			      SHFL_CF_ACCESS_READWRITE |
-			      (is_dir ? SHFL_CF_DIRECTORY : 0);
+	params.create_flags = SHFL_CF_ACT_CREATE_IF_NEW | SHFL_CF_ACCESS_READWRITE;
+	if (is_dir)
+		params.create_flags |= SHFL_CF_DIRECTORY;
+	if (excl)
+		params.create_flags |= SHFL_CF_ACT_FAIL_IF_EXISTS;
+
 	params.info.attr.mode = (mode & 0777) |
 				(is_dir ? SHFL_TYPE_DIRECTORY : SHFL_TYPE_FILE);
 	params.info.attr.additional = SHFLFSOBJATTRADD_NOTHING;
@@ -292,14 +294,14 @@ static int vboxsf_dir_mkfile(struct user
 			     struct inode *parent, struct dentry *dentry,
 			     umode_t mode, bool excl)
 {
-	return vboxsf_dir_create(parent, dentry, mode, 0);
+	return vboxsf_dir_create(parent, dentry, mode, false, excl);
 }
 
 static int vboxsf_dir_mkdir(struct user_namespace *mnt_userns,
 			    struct inode *parent, struct dentry *dentry,
 			    umode_t mode)
 {
-	return vboxsf_dir_create(parent, dentry, mode, 1);
+	return vboxsf_dir_create(parent, dentry, mode, true, true);
 }
 
 static int vboxsf_dir_unlink(struct inode *parent, struct dentry *dentry)