From a65e58e791a1690da8de731c8391816a22f5555c Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Sat, 20 Mar 2021 13:26:22 +0100 Subject: 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: Vivek Goyal Cc: Christoph Hellwig Cc: Darrick J. Wong Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner --- fs/inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/inode.c') diff --git a/fs/inode.c b/fs/inode.c index a047ab306f9a..81a6a59b7dd3 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -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); -- cgit v1.2.3 From db998553cf11dd697485ac6142adbb35d21fff10 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Sat, 20 Mar 2021 13:26:24 +0100 Subject: fs: introduce two inode i_{u,g}id initialization helpers Give filesystem two little helpers that do the right thing when initializing the i_uid and i_gid fields on idmapped and non-idmapped mounts. Filesystems shouldn't have to be concerned with too many details. Link: https://lore.kernel.org/r/20210320122623.599086-5-christian.brauner@ubuntu.com Inspired-by: Vivek Goyal Cc: Christoph Hellwig Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner --- fs/ext4/ialloc.c | 2 +- fs/inode.c | 4 ++-- fs/xfs/xfs_inode.c | 2 +- include/linux/fs.h | 28 ++++++++++++++++++++++++++++ 4 files changed, 32 insertions(+), 4 deletions(-) (limited to 'fs/inode.c') diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index d0dc12197346..755a68bb7e22 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -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 = mapped_fsuid(mnt_userns); + inode_fsuid_set(inode, mnt_userns); inode->i_gid = dir->i_gid; } else inode_init_owner(mnt_userns, inode, dir, mode); diff --git a/fs/inode.c b/fs/inode.c index 81a6a59b7dd3..21c5a620ca89 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -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 = mapped_fsuid(mnt_userns); + inode_fsuid_set(inode, 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 = mapped_fsgid(mnt_userns); + inode_fsgid_set(inode, mnt_userns); inode->i_mode = mode; } EXPORT_SYMBOL(inode_init_owner); diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index dc91f8c34d35..2a8bdf33e6c4 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -812,7 +812,7 @@ xfs_init_new_inode( if (dir && !(dir->i_mode & S_ISGID) && (mp->m_flags & XFS_MOUNT_GRPID)) { - inode->i_uid = mapped_fsuid(mnt_userns); + inode_fsuid_set(inode, mnt_userns); inode->i_gid = dir->i_gid; inode->i_mode = mode; } else { diff --git a/include/linux/fs.h b/include/linux/fs.h index e9e7e799425e..3eaf5f27a0e4 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1692,6 +1692,34 @@ static inline kgid_t mapped_fsgid(struct user_namespace *mnt_userns) return kgid_from_mnt(mnt_userns, current_fsgid()); } +/** + * inode_fsuid_set - initialize inode's i_uid field with callers fsuid + * @inode: inode to initialize + * @mnt_userns: user namespace of the mount the inode was found from + * + * Initialize the i_uid field of @inode. If the inode was found/created via + * an idmapped mount map the caller's fsuid according to @mnt_users. + */ +static inline void inode_fsuid_set(struct inode *inode, + struct user_namespace *mnt_userns) +{ + inode->i_uid = mapped_fsuid(mnt_userns); +} + +/** + * inode_fsgid_set - initialize inode's i_gid field with callers fsgid + * @inode: inode to initialize + * @mnt_userns: user namespace of the mount the inode was found from + * + * Initialize the i_gid field of @inode. If the inode was found/created via + * an idmapped mount map the caller's fsgid according to @mnt_users. + */ +static inline void inode_fsgid_set(struct inode *inode, + struct user_namespace *mnt_userns) +{ + inode->i_gid = mapped_fsgid(mnt_userns); +} + /** * fsuidgid_has_mapping() - check whether caller's fsuid/fsgid is mapped * @sb: the superblock we want a mapping in -- cgit v1.2.3