exfat: handle idmapped mounts

Pass the idmapped mount information to the different helper
functions. Adapt the uid/gid checks in exfat_setattr to use the
vfsuid/vfsgid helpers.

Based on the fat implementation in commit 4b7899368108
("fat: handle idmapped mounts") by Christian Brauner.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

diff --git a/fs/exfat/file.c b/fs/exfat/file.c
index 9adfc38ca7dac01ee004315a7b5d11486ee20f10..64c31867bc7615b55f8d9c524b8fb13a9b99f706 100644 (file)
--- a/fs/exfat/file.c
+++ b/fs/exfat/file.c
@@ -89,12 +89,14 @@ free_clu:
        return -EIO;
 }
 
-static bool exfat_allow_set_time(struct exfat_sb_info *sbi, struct inode *inode)
+static bool exfat_allow_set_time(struct mnt_idmap *idmap,
+                                struct exfat_sb_info *sbi, struct inode *inode)
 {
        mode_t allow_utime = sbi->options.allow_utime;
 
-       if (!uid_eq(current_fsuid(), inode->i_uid)) {
-               if (in_group_p(inode->i_gid))
+       if (!vfsuid_eq_kuid(i_uid_into_vfsuid(idmap, inode),
+                           current_fsuid())) {
+               if (vfsgid_in_group_p(i_gid_into_vfsgid(idmap, inode)))
                        allow_utime >>= 3;
                if (allow_utime & MAY_WRITE)
                        return true;
@@ -283,7 +285,7 @@ int exfat_getattr(struct mnt_idmap *idmap, const struct path *path,
        struct inode *inode = d_backing_inode(path->dentry);
        struct exfat_inode_info *ei = EXFAT_I(inode);
 
-       generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
+       generic_fillattr(idmap, request_mask, inode, stat);
        exfat_truncate_atime(&stat->atime);
        stat->result_mask |= STATX_BTIME;
        stat->btime.tv_sec = ei->i_crtime.tv_sec;
@@ -311,20 +313,22 @@ int exfat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
        /* Check for setting the inode time. */
        ia_valid = attr->ia_valid;
        if ((ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) &&
-           exfat_allow_set_time(sbi, inode)) {
+           exfat_allow_set_time(idmap, sbi, inode)) {
                attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET |
                                ATTR_TIMES_SET);
        }
 
-       error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
+       error = setattr_prepare(idmap, dentry, attr);
        attr->ia_valid = ia_valid;
        if (error)
                goto out;
 
        if (((attr->ia_valid & ATTR_UID) &&
-            !uid_eq(attr->ia_uid, sbi->options.fs_uid)) ||
+             (!uid_eq(from_vfsuid(idmap, i_user_ns(inode), attr->ia_vfsuid),
+              sbi->options.fs_uid))) ||
            ((attr->ia_valid & ATTR_GID) &&
-            !gid_eq(attr->ia_gid, sbi->options.fs_gid)) ||
+             (!gid_eq(from_vfsgid(idmap, i_user_ns(inode), attr->ia_vfsgid),
+              sbi->options.fs_gid))) ||
            ((attr->ia_valid & ATTR_MODE) &&
             (attr->ia_mode & ~(S_IFREG | S_IFLNK | S_IFDIR | 0777)))) {
                error = -EPERM;
@@ -343,7 +347,7 @@ int exfat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
        if (attr->ia_valid & ATTR_SIZE)
                inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
 
-       setattr_copy(&nop_mnt_idmap, inode, attr);
+       setattr_copy(idmap, inode, attr);
        exfat_truncate_inode_atime(inode);
 
        if (attr->ia_valid & ATTR_SIZE) {

diff --git a/fs/exfat/super.c b/fs/exfat/super.c
index 3d5ea2cfad66b988976bedd6eb0fec97f6ff8ad5..1f2b3b0c4923d435b8984819bca44dffc1c63b05 100644 (file)
--- a/fs/exfat/super.c
+++ b/fs/exfat/super.c
@@ -788,7 +788,7 @@ static struct file_system_type exfat_fs_type = {
        .init_fs_context        = exfat_init_fs_context,
        .parameters             = exfat_parameters,
        .kill_sb                = exfat_kill_sb,
-       .fs_flags               = FS_REQUIRES_DEV,
+       .fs_flags               = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
 };
 
 static void exfat_inode_init_once(void *foo)