[PATCH 5.10 11/19] vboxsf: Honor excl flag to the dir-inode create op

From: Greg Kroah-Hartman
Date: Fri Aug 13 2021 - 11:20:41 EST


From: Hans de Goede <hdegoede@xxxxxxxxxx>

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@xxxxxxxxxx>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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;
@@ -291,13 +293,13 @@ static int vboxsf_dir_create(struct inod
static int vboxsf_dir_mkfile(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 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)