Unverified Commit a65e58e7 authored by Christian Brauner's avatar Christian Brauner
Browse files

fs: document and rename fsid helpers 

Vivek pointed out that the fs{g,u}id_into_mnt() naming scheme can be
misleading as it could be understood as implying they do the exact same
thing as i_{g,u}id_into_mnt(). The original motivation for this naming
scheme was to signal to callers that the helpers will always take care
to map the k{g,u}id such that the ownership is expressed in terms of the
mnt_users.
Get rid of the confusion by renaming those helpers to something more
sensible. Al suggested mapped_fs{g,u}id() which seems a really good fit.
Usually filesystems don't need to bother with these helpers directly
only in some cases where they allocate objects that carry {g,u}ids which
are either filesystem specific (e.g. xfs quota objects) or don't have a
clean set of helpers as inodes have.

Link: https://lore.kernel.org/r/20210320122623.599086-3-christian.brauner@ubuntu.com


Inspired-by: default avatarVivek Goyal <vgoyal@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
parent 1bd66c1a

fs/ext4/ialloc.c

+1 −1
Original line number Diff line number Diff line
@@ -970,7 +970,7 @@ struct inode *__ext4_new_inode(struct user_namespace *mnt_userns, 
		i_gid_write(inode, owner[1]);

	} else if (test_opt(sb, GRPID)) {

		inode->i_mode = mode;

		inode->i_uid = fsuid_into_mnt(mnt_userns);

		inode->i_uid = mapped_fsuid(mnt_userns);

		inode->i_gid = dir->i_gid;

	} else

		inode_init_owner(mnt_userns, inode, dir, mode);

fs/inode.c

+2 −2
Original line number Diff line number Diff line
@@ -2148,7 +2148,7 @@ EXPORT_SYMBOL(init_special_inode); 
void inode_init_owner(struct user_namespace *mnt_userns, struct inode *inode,

		      const struct inode *dir, umode_t mode)

{

	inode->i_uid = fsuid_into_mnt(mnt_userns);

	inode->i_uid = mapped_fsuid(mnt_userns);

	if (dir && dir->i_mode & S_ISGID) {

		inode->i_gid = dir->i_gid;
@@ -2160,7 +2160,7 @@ void inode_init_owner(struct user_namespace *mnt_userns, struct inode *inode, 
			 !capable_wrt_inode_uidgid(mnt_userns, dir, CAP_FSETID))

			mode &= ~S_ISGID;

	} else

		inode->i_gid = fsgid_into_mnt(mnt_userns);

		inode->i_gid = mapped_fsgid(mnt_userns);

	inode->i_mode = mode;

}

EXPORT_SYMBOL(inode_init_owner);

fs/namei.c

+4 −4
Original line number Diff line number Diff line
@@ -2830,8 +2830,8 @@ static inline int may_create(struct user_namespace *mnt_userns, 
	if (IS_DEADDIR(dir))

		return -ENOENT;

	s_user_ns = dir->i_sb->s_user_ns;

	if (!kuid_has_mapping(s_user_ns, fsuid_into_mnt(mnt_userns)) ||

	    !kgid_has_mapping(s_user_ns, fsgid_into_mnt(mnt_userns)))

	if (!kuid_has_mapping(s_user_ns, mapped_fsuid(mnt_userns)) ||

	    !kgid_has_mapping(s_user_ns, mapped_fsgid(mnt_userns)))

		return -EOVERFLOW;

	return inode_permission(mnt_userns, dir, MAY_WRITE | MAY_EXEC);

}
@@ -3040,8 +3040,8 @@ static int may_o_create(struct user_namespace *mnt_userns, 
		return error;



	s_user_ns = dir->dentry->d_sb->s_user_ns;

	if (!kuid_has_mapping(s_user_ns, fsuid_into_mnt(mnt_userns)) ||

	    !kgid_has_mapping(s_user_ns, fsgid_into_mnt(mnt_userns)))

	if (!kuid_has_mapping(s_user_ns, mapped_fsuid(mnt_userns)) ||

	    !kgid_has_mapping(s_user_ns, mapped_fsgid(mnt_userns)))

		return -EOVERFLOW;



	error = inode_permission(mnt_userns, dir->dentry->d_inode,

fs/xfs/xfs_inode.c

+5 −5
Original line number Diff line number Diff line
@@ -812,7 +812,7 @@ xfs_init_new_inode( 


	if (dir && !(dir->i_mode & S_ISGID) &&

	    (mp->m_flags & XFS_MOUNT_GRPID)) {

		inode->i_uid = fsuid_into_mnt(mnt_userns);

		inode->i_uid = mapped_fsuid(mnt_userns);

		inode->i_gid = dir->i_gid;

		inode->i_mode = mode;

	} else {
@@ -1007,8 +1007,8 @@ xfs_create( 
	/*

	 * Make sure that we have allocated dquot(s) on disk.

	 */

	error = xfs_qm_vop_dqalloc(dp, fsuid_into_mnt(mnt_userns),

			fsgid_into_mnt(mnt_userns), prid,

	error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns),

			mapped_fsgid(mnt_userns), prid,

			XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT,

			&udqp, &gdqp, &pdqp);

	if (error)
@@ -1158,8 +1158,8 @@ xfs_create_tmpfile( 
	/*

	 * Make sure that we have allocated dquot(s) on disk.

	 */

	error = xfs_qm_vop_dqalloc(dp, fsuid_into_mnt(mnt_userns),

			fsgid_into_mnt(mnt_userns), prid,

	error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns),

			mapped_fsgid(mnt_userns), prid,

			XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT,

			&udqp, &gdqp, &pdqp);

	if (error)

fs/xfs/xfs_symlink.c

+2 −2
Original line number Diff line number Diff line
@@ -182,8 +182,8 @@ xfs_symlink( 
	/*

	 * Make sure that we have allocated dquot(s) on disk.

	 */

	error = xfs_qm_vop_dqalloc(dp, fsuid_into_mnt(mnt_userns),

			fsgid_into_mnt(mnt_userns), prid,

	error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns),

			mapped_fsgid(mnt_userns), prid,

			XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT,

			&udqp, &gdqp, &pdqp);

	if (error)