fs: make helpers idmap mount aware

Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has been marked with. This can be used for
additional permission checking and also to enable filesystems to
translate between uids and gids if they need to. We have implemented all
relevant helpers in earlier patches.

As requested we simply extend the exisiting inode method instead of
introducing new ones. This is a little more code churn but it's mostly
mechanical and doesnt't leave us with additional inode methods.

Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

3 files changed, 19 insertions, 15 deletions

diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index a8881ed61620..d9d8d7794eff 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -280,8 +280,8 @@ static int ubifs_prepare_create(struct inode *dir, struct dentry *dentry,
 	return fscrypt_setup_filename(dir, &dentry->d_name, 0, nm);
 }
 
-static int ubifs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
-			bool excl)
+static int ubifs_create(struct user_namespace *mnt_userns, struct inode *dir,
+			struct dentry *dentry, umode_t mode, bool excl)
 {
 	struct inode *inode;
 	struct ubifs_info *c = dir->i_sb->s_fs_info;
@@ -441,8 +441,8 @@ out_budg:
 	return err;
 }
 
-static int ubifs_tmpfile(struct inode *dir, struct dentry *dentry,
-			 umode_t mode)
+static int ubifs_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
+			 struct dentry *dentry, umode_t mode)
 {
 	return do_tmpfile(dir, dentry, mode, NULL);
 }
@@ -942,7 +942,8 @@ out_fname:
 	return err;
 }
 
-static int ubifs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+static int ubifs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+		       struct dentry *dentry, umode_t mode)
 {
 	struct inode *inode;
 	struct ubifs_inode *dir_ui = ubifs_inode(dir);
@@ -1013,8 +1014,8 @@ out_budg:
 	return err;
 }
 
-static int ubifs_mknod(struct inode *dir, struct dentry *dentry,
-		       umode_t mode, dev_t rdev)
+static int ubifs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
+		       struct dentry *dentry, umode_t mode, dev_t rdev)
 {
 	struct inode *inode;
 	struct ubifs_inode *ui;
@@ -1102,8 +1103,8 @@ out_budg:
 	return err;
 }
 
-static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
-			 const char *symname)
+static int ubifs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+			 struct dentry *dentry, const char *symname)
 {
 	struct inode *inode;
 	struct ubifs_inode *ui;
@@ -1542,7 +1543,8 @@ static int ubifs_xrename(struct inode *old_dir, struct dentry *old_dentry,
 	return err;
 }
 
-static int ubifs_rename(struct inode *old_dir, struct dentry *old_dentry,
+static int ubifs_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)
 {
@@ -1566,8 +1568,8 @@ static int ubifs_rename(struct inode *old_dir, struct dentry *old_dentry,
 	return do_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
 }
 
-int ubifs_getattr(const struct path *path, struct kstat *stat,
-		  u32 request_mask, unsigned int flags)
+int ubifs_getattr(struct user_namespace *mnt_userns, const struct path *path,
+		  struct kstat *stat, u32 request_mask, unsigned int flags)
 {
 	loff_t size;
 	struct inode *inode = d_inode(path->dentry);
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 76ef392b1e41..0e4b4be3aa26 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1257,7 +1257,8 @@ static int do_setattr(struct ubifs_info *c, struct inode *inode,
 	return err;
 }
 
-int ubifs_setattr(struct dentry *dentry, struct iattr *attr)
+int ubifs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+		  struct iattr *attr)
 {
 	int err;
 	struct inode *inode = d_inode(dentry);
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index fc2cdde3b549..7fdfdbda4b8a 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -1989,13 +1989,14 @@ int ubifs_calc_dark(const struct ubifs_info *c, int spc);
 
 /* file.c */
 int ubifs_fsync(struct file *file, loff_t start, loff_t end, int datasync);
-int ubifs_setattr(struct dentry *dentry, struct iattr *attr);
+int ubifs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+		  struct iattr *attr);
 int ubifs_update_time(struct inode *inode, struct timespec64 *time, int flags);
 
 /* dir.c */
 struct inode *ubifs_new_inode(struct ubifs_info *c, struct inode *dir,
 			      umode_t mode);
-int ubifs_getattr(const struct path *path, struct kstat *stat,
+int ubifs_getattr(struct user_namespace *mnt_userns, const struct path *path, struct kstat *stat,
 		  u32 request_mask, unsigned int flags);
 int ubifs_check_dir_empty(struct inode *dir);