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>

6 files changed, 35 insertions, 20 deletions

diff --git a/fs/ocfs2/acl.c b/fs/ocfs2/acl.c
index 990756cee4bd..5259badabb56 100644
--- a/fs/ocfs2/acl.c
+++ b/fs/ocfs2/acl.c
@@ -262,7 +262,8 @@ static int ocfs2_set_acl(handle_t *handle,
 	return ret;
 }
 
-int ocfs2_iop_set_acl(struct inode *inode, struct posix_acl *acl, int type)
+int ocfs2_iop_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
+		      struct posix_acl *acl, int type)
 {
 	struct buffer_head *bh = NULL;
 	int status, had_lock;
diff --git a/fs/ocfs2/acl.h b/fs/ocfs2/acl.h
index 127b13432146..4e86450917b2 100644
--- a/fs/ocfs2/acl.h
+++ b/fs/ocfs2/acl.h
@@ -19,7 +19,8 @@ struct ocfs2_acl_entry {
 };
 
 struct posix_acl *ocfs2_iop_get_acl(struct inode *inode, int type);
-int ocfs2_iop_set_acl(struct inode *inode, struct posix_acl *acl, int type);
+int ocfs2_iop_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
+		      struct posix_acl *acl, int type);
 extern int ocfs2_acl_chmod(struct inode *, struct buffer_head *);
 extern int ocfs2_init_acl(handle_t *, struct inode *, struct inode *,
 			  struct buffer_head *, struct buffer_head *,
diff --git a/fs/ocfs2/dlmfs/dlmfs.c b/fs/ocfs2/dlmfs/dlmfs.c
index 9fa66cd1f622..b2870f1a31df 100644
--- a/fs/ocfs2/dlmfs/dlmfs.c
+++ b/fs/ocfs2/dlmfs/dlmfs.c
@@ -190,7 +190,8 @@ static int dlmfs_file_release(struct inode *inode,
  * We do ->setattr() just to override size changes.  Our size is the size
  * of the LVB and nothing else.
  */
-static int dlmfs_file_setattr(struct dentry *dentry, struct iattr *attr)
+static int dlmfs_file_setattr(struct user_namespace *mnt_userns,
+			      struct dentry *dentry, struct iattr *attr)
 {
 	int error;
 	struct inode *inode = d_inode(dentry);
@@ -395,7 +396,8 @@ static struct inode *dlmfs_get_inode(struct inode *parent,
  * File creation. Allocate an inode, and we're done..
  */
 /* SMP-safe */
-static int dlmfs_mkdir(struct inode * dir,
+static int dlmfs_mkdir(struct user_namespace * mnt_userns,
+		       struct inode * dir,
 		       struct dentry * dentry,
 		       umode_t mode)
 {
@@ -443,7 +445,8 @@ bail:
 	return status;
 }
 
-static int dlmfs_create(struct inode *dir,
+static int dlmfs_create(struct user_namespace *mnt_userns,
+			struct inode *dir,
 			struct dentry *dentry,
 			umode_t mode,
 			bool excl)
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index a070d4c9b6ed..e3039d973acd 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -1112,7 +1112,8 @@ out:
 	return ret;
 }
 
-int ocfs2_setattr(struct dentry *dentry, struct iattr *attr)
+int ocfs2_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+		  struct iattr *attr)
 {
 	int status = 0, size_change;
 	int inode_locked = 0;
@@ -1298,8 +1299,8 @@ bail:
 	return status;
 }
 
-int ocfs2_getattr(const struct path *path, struct kstat *stat,
-		  u32 request_mask, unsigned int flags)
+int ocfs2_getattr(struct user_namespace *mnt_userns, const struct path *path,
+		  struct kstat *stat, u32 request_mask, unsigned int flags)
 {
 	struct inode *inode = d_inode(path->dentry);
 	struct super_block *sb = path->dentry->d_sb;
@@ -1330,7 +1331,8 @@ bail:
 	return err;
 }
 
-int ocfs2_permission(struct inode *inode, int mask)
+int ocfs2_permission(struct user_namespace *mnt_userns, struct inode *inode,
+		     int mask)
 {
 	int ret, had_lock;
 	struct ocfs2_lock_holder oh;
diff --git a/fs/ocfs2/file.h b/fs/ocfs2/file.h
index 4832cbceba5b..8536cec5f122 100644
--- a/fs/ocfs2/file.h
+++ b/fs/ocfs2/file.h
@@ -51,10 +51,13 @@ int ocfs2_extend_no_holes(struct inode *inode, struct buffer_head *di_bh,
 			  u64 new_i_size, u64 zero_to);
 int ocfs2_zero_extend(struct inode *inode, struct buffer_head *di_bh,
 		      loff_t zero_to);
-int ocfs2_setattr(struct dentry *dentry, struct iattr *attr);
-int ocfs2_getattr(const struct path *path, struct kstat *stat,
-		  u32 request_mask, unsigned int flags);
-int ocfs2_permission(struct inode *inode, int mask);
+int ocfs2_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+		  struct iattr *attr);
+int ocfs2_getattr(struct user_namespace *mnt_userns, const struct path *path,
+		  struct kstat *stat, u32 request_mask, unsigned int flags);
+int ocfs2_permission(struct user_namespace *mnt_userns,
+		     struct inode *inode,
+		     int mask);
 
 int ocfs2_should_update_atime(struct inode *inode,
 			      struct vfsmount *vfsmnt);
diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
index 908b79e1082b..3abdd36da2e2 100644
--- a/fs/ocfs2/namei.c
+++ b/fs/ocfs2/namei.c
@@ -221,7 +221,8 @@ static void ocfs2_cleanup_add_entry_failure(struct ocfs2_super *osb,
 	iput(inode);
 }
 
-static int ocfs2_mknod(struct inode *dir,
+static int ocfs2_mknod(struct user_namespace *mnt_userns,
+		       struct inode *dir,
 		       struct dentry *dentry,
 		       umode_t mode,
 		       dev_t dev)
@@ -645,7 +646,8 @@ static int ocfs2_mknod_locked(struct ocfs2_super *osb,
 	return status;
 }
 
-static int ocfs2_mkdir(struct inode *dir,
+static int ocfs2_mkdir(struct user_namespace *mnt_userns,
+		       struct inode *dir,
 		       struct dentry *dentry,
 		       umode_t mode)
 {
@@ -653,14 +655,15 @@ static int ocfs2_mkdir(struct inode *dir,
 
 	trace_ocfs2_mkdir(dir, dentry, dentry->d_name.len, dentry->d_name.name,
 			  OCFS2_I(dir)->ip_blkno, mode);
-	ret = ocfs2_mknod(dir, dentry, mode | S_IFDIR, 0);
+	ret = ocfs2_mknod(&init_user_ns, dir, dentry, mode | S_IFDIR, 0);
 	if (ret)
 		mlog_errno(ret);
 
 	return ret;
 }
 
-static int ocfs2_create(struct inode *dir,
+static int ocfs2_create(struct user_namespace *mnt_userns,
+			struct inode *dir,
 			struct dentry *dentry,
 			umode_t mode,
 			bool excl)
@@ -669,7 +672,7 @@ static int ocfs2_create(struct inode *dir,
 
 	trace_ocfs2_create(dir, dentry, dentry->d_name.len, dentry->d_name.name,
 			   (unsigned long long)OCFS2_I(dir)->ip_blkno, mode);
-	ret = ocfs2_mknod(dir, dentry, mode | S_IFREG, 0);
+	ret = ocfs2_mknod(&init_user_ns, dir, dentry, mode | S_IFREG, 0);
 	if (ret)
 		mlog_errno(ret);
 
@@ -1195,7 +1198,8 @@ static void ocfs2_double_unlock(struct inode *inode1, struct inode *inode2)
 		ocfs2_inode_unlock(inode2, 1);
 }
 
-static int ocfs2_rename(struct inode *old_dir,
+static int ocfs2_rename(struct user_namespace *mnt_userns,
+			struct inode *old_dir,
 			struct dentry *old_dentry,
 			struct inode *new_dir,
 			struct dentry *new_dentry,
@@ -1784,7 +1788,8 @@ bail:
 	return status;
 }
 
-static int ocfs2_symlink(struct inode *dir,
+static int ocfs2_symlink(struct user_namespace *mnt_userns,
+			 struct inode *dir,
 			 struct dentry *dentry,
 			 const char *symname)
 {