File systems want to hold a shared lock for DIO writes,
but may need to drop file priveliges - that a requires an
exclusive lock. The new export function file_needs_remove_privs()
is added in order to first check if that is needed.
Cc: Miklos Szeredi <miklos@xxxxxxxxxx>
Cc: Dharmendra Singh <dsingh@xxxxxxx>
Cc: Josef Bacik <josef@xxxxxxxxxxxxxx>
Cc: linux-btrfs@xxxxxxxxxxxxxxx
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: linux-fsdevel@xxxxxxxxxxxxxxx
Signed-off-by: Bernd Schubert <bschubert@xxxxxxx>
---
fs/inode.c | 8 ++++++++
include/linux/fs.h | 1 +
2 files changed, 9 insertions(+)
diff --git a/fs/inode.c b/fs/inode.c
index 67611a360031..9b05db602e41 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2013,6 +2013,14 @@ int dentry_needs_remove_privs(struct mnt_idmap *idmap,
return mask;
}
+int file_needs_remove_privs(struct file *file)
+{
+ struct dentry *dentry = file_dentry(file);
+
+ return dentry_needs_remove_privs(file_mnt_idmap(file), dentry);
+}
+EXPORT_SYMBOL_GPL(file_needs_remove_privs);
+
static int __remove_privs(struct mnt_idmap *idmap,
struct dentry *dentry, int kill)
{
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 562f2623c9c9..9245f0de00bc 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2721,6 +2721,7 @@ extern struct inode *new_inode_pseudo(struct super_block *sb);
extern struct inode *new_inode(struct super_block *sb);
extern void free_inode_nonrcu(struct inode *inode);
extern int setattr_should_drop_suidgid(struct mnt_idmap *, struct inode *);
+int file_needs_remove_privs(struct file *);
extern int file_remove_privs(struct file *);
int setattr_should_drop_sgid(struct mnt_idmap *idmap,
const struct inode *inode);
--
2.39.2
