[PATCH] ovl: fix missing upper fs freeze protection on copy up for ioctl

[Amir Goldstein <amir73il@gmail.com>]

Generalize the helper ovl_open_maybe_copy_up() and use it to copy up
file with data before FS_IOC_SETFLAGS ioctl.

Fixes: dab5ca8fd9dd ("ovl: add lsattr/chattr support")
Cc: <stable@vger.kernel.org> # v4.19
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 fs/overlayfs/copy_up.c   | 6 +++---
 fs/overlayfs/file.c      | 5 ++---
 fs/overlayfs/overlayfs.h | 2 +-
 3 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 48119b23375b..0c0e11d529d0 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -885,14 +885,14 @@ static bool ovl_open_need_copy_up(struct dentry *dentry, int flags)
 	return true;
 }
 
-int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags)
+int ovl_maybe_copy_up(struct dentry *dentry, int flags)
 {
 	int err = 0;
 
-	if (ovl_open_need_copy_up(dentry, file_flags)) {
+	if (ovl_open_need_copy_up(dentry, flags)) {
 		err = ovl_want_write(dentry);
 		if (!err) {
-			err = ovl_copy_up_flags(dentry, file_flags);
+			err = ovl_copy_up_flags(dentry, flags);
 			ovl_drop_write(dentry);
 		}
 	}
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 84dd957efa24..50e4407398d8 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -116,11 +116,10 @@ static int ovl_real_fdget(const struct file *file, struct fd *real)
 
 static int ovl_open(struct inode *inode, struct file *file)
 {
-	struct dentry *dentry = file_dentry(file);
 	struct file *realfile;
 	int err;
 
-	err = ovl_open_maybe_copy_up(dentry, file->f_flags);
+	err = ovl_maybe_copy_up(file_dentry(file), file->f_flags);
 	if (err)
 		return err;
 
@@ -390,7 +389,7 @@ static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		if (ret)
 			return ret;
 
-		ret = ovl_copy_up_with_data(file_dentry(file));
+		ret = ovl_maybe_copy_up(file_dentry(file), O_WRONLY);
 		if (!ret) {
 			ret = ovl_real_ioctl(file, cmd, arg);
 
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 5e45cb3630a0..767eeaf73bf1 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -419,7 +419,7 @@ extern const struct file_operations ovl_file_operations;
 int ovl_copy_up(struct dentry *dentry);
 int ovl_copy_up_with_data(struct dentry *dentry);
 int ovl_copy_up_flags(struct dentry *dentry, int flags);
-int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);
+int ovl_maybe_copy_up(struct dentry *dentry, int flags);
 int ovl_copy_xattr(struct dentry *old, struct dentry *new);
 int ovl_set_attr(struct dentry *upper, struct kstat *stat);
 struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper);
-- 
2.17.1