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>

5 files changed, 32 insertions, 23 deletions

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index ce14e6f8adb6..39e51dcf796f 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -305,7 +305,8 @@ static long cifs_fallocate(struct file *file, int mode, loff_t off, loff_t len)
 	return -EOPNOTSUPP;
 }
 
-static int cifs_permission(struct inode *inode, int mask)
+static int cifs_permission(struct user_namespace *mnt_userns,
+			   struct inode *inode, int mask)
 {
 	struct cifs_sb_info *cifs_sb;
 
diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index 2307bb0f6147..71e9c6abb2a6 100644
--- a/fs/cifs/cifsfs.h
+++ b/fs/cifs/cifsfs.h
@@ -62,19 +62,22 @@ extern void cifs_sb_deactive(struct super_block *sb);
 /* Functions related to inodes */
 extern const struct inode_operations cifs_dir_inode_ops;
 extern struct inode *cifs_root_iget(struct super_block *);
-extern int cifs_create(struct inode *, struct dentry *, umode_t,
-		       bool excl);
+extern int cifs_create(struct user_namespace *, struct inode *,
+		       struct dentry *, umode_t, bool excl);
 extern int cifs_atomic_open(struct inode *, struct dentry *,
 			    struct file *, unsigned, umode_t);
 extern struct dentry *cifs_lookup(struct inode *, struct dentry *,
 				  unsigned int);
 extern int cifs_unlink(struct inode *dir, struct dentry *dentry);
 extern int cifs_hardlink(struct dentry *, struct inode *, struct dentry *);
-extern int cifs_mknod(struct inode *, struct dentry *, umode_t, dev_t);
-extern int cifs_mkdir(struct inode *, struct dentry *, umode_t);
+extern int cifs_mknod(struct user_namespace *, struct inode *, struct dentry *,
+		      umode_t, dev_t);
+extern int cifs_mkdir(struct user_namespace *, struct inode *, struct dentry *,
+		      umode_t);
 extern int cifs_rmdir(struct inode *, struct dentry *);
-extern int cifs_rename2(struct inode *, struct dentry *, struct inode *,
-			struct dentry *, unsigned int);
+extern int cifs_rename2(struct user_namespace *, struct inode *,
+			struct dentry *, struct inode *, struct dentry *,
+			unsigned int);
 extern int cifs_revalidate_file_attr(struct file *filp);
 extern int cifs_revalidate_dentry_attr(struct dentry *);
 extern int cifs_revalidate_file(struct file *filp);
@@ -82,8 +85,10 @@ extern int cifs_revalidate_dentry(struct dentry *);
 extern int cifs_invalidate_mapping(struct inode *inode);
 extern int cifs_revalidate_mapping(struct inode *inode);
 extern int cifs_zap_mapping(struct inode *inode);
-extern int cifs_getattr(const struct path *, struct kstat *, u32, unsigned int);
-extern int cifs_setattr(struct dentry *, struct iattr *);
+extern int cifs_getattr(struct user_namespace *, const struct path *,
+			struct kstat *, u32, unsigned int);
+extern int cifs_setattr(struct user_namespace *, struct dentry *,
+			struct iattr *);
 extern int cifs_fiemap(struct inode *, struct fiemap_extent_info *, u64 start,
 		       u64 len);
 
@@ -132,8 +137,8 @@ extern struct vfsmount *cifs_dfs_d_automount(struct path *path);
 /* Functions related to symlinks */
 extern const char *cifs_get_link(struct dentry *, struct inode *,
 			struct delayed_call *);
-extern int cifs_symlink(struct inode *inode, struct dentry *direntry,
-			const char *symname);
+extern int cifs_symlink(struct user_namespace *mnt_userns, struct inode *inode,
+			struct dentry *direntry, const char *symname);
 
 #ifdef CONFIG_CIFS_XATTR
 extern const struct xattr_handler *cifs_xattr_handlers[];
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 68900f1629bf..68f4f8536e6a 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -567,8 +567,8 @@ out_free_xid:
 	return rc;
 }
 
-int cifs_create(struct inode *inode, struct dentry *direntry, umode_t mode,
-		bool excl)
+int cifs_create(struct user_namespace *mnt_userns, struct inode *inode,
+		struct dentry *direntry, umode_t mode, bool excl)
 {
 	int rc;
 	unsigned int xid = get_xid();
@@ -611,8 +611,8 @@ out_free_xid:
 	return rc;
 }
 
-int cifs_mknod(struct inode *inode, struct dentry *direntry, umode_t mode,
-		dev_t device_number)
+int cifs_mknod(struct user_namespace *mnt_userns, struct inode *inode,
+	       struct dentry *direntry, umode_t mode, dev_t device_number)
 {
 	int rc = -EPERM;
 	unsigned int xid;
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 374abce7efaf..3e9c7bb23f26 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -1857,7 +1857,8 @@ posix_mkdir_get_info:
 	goto posix_mkdir_out;
 }
 
-int cifs_mkdir(struct inode *inode, struct dentry *direntry, umode_t mode)
+int cifs_mkdir(struct user_namespace *mnt_userns, struct inode *inode,
+	       struct dentry *direntry, umode_t mode)
 {
 	int rc = 0;
 	unsigned int xid;
@@ -2067,9 +2068,9 @@ do_rename_exit:
 }
 
 int
-cifs_rename2(struct inode *source_dir, struct dentry *source_dentry,
-	     struct inode *target_dir, struct dentry *target_dentry,
-	     unsigned int flags)
+cifs_rename2(struct user_namespace *mnt_userns, struct inode *source_dir,
+	     struct dentry *source_dentry, struct inode *target_dir,
+	     struct dentry *target_dentry, unsigned int flags)
 {
 	char *from_name = NULL;
 	char *to_name = NULL;
@@ -2370,8 +2371,8 @@ int cifs_revalidate_dentry(struct dentry *dentry)
 	return cifs_revalidate_mapping(inode);
 }
 
-int cifs_getattr(const struct path *path, struct kstat *stat,
-		 u32 request_mask, unsigned int flags)
+int cifs_getattr(struct user_namespace *mnt_userns, const struct path *path,
+		 struct kstat *stat, u32 request_mask, unsigned int flags)
 {
 	struct dentry *dentry = path->dentry;
 	struct cifs_sb_info *cifs_sb = CIFS_SB(dentry->d_sb);
@@ -2923,7 +2924,8 @@ cifs_setattr_exit:
 }
 
 int
-cifs_setattr(struct dentry *direntry, struct iattr *attrs)
+cifs_setattr(struct user_namespace *mnt_userns, struct dentry *direntry,
+	     struct iattr *attrs)
 {
 	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
 	struct cifs_tcon *pTcon = cifs_sb_master_tcon(cifs_sb);
diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 94dab4309fbb..7c5878a645d9 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -661,7 +661,8 @@ cifs_get_link(struct dentry *direntry, struct inode *inode,
 }
 
 int
-cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
+cifs_symlink(struct user_namespace *mnt_userns, struct inode *inode,
+	     struct dentry *direntry, const char *symname)
 {
 	int rc = -EOPNOTSUPP;
 	unsigned int xid;