We enable idmapped mounts for bcachefs. Here, we just pass down the user_namespace argument from the VFS methods to the relevant helpers. The idmap test in bcachefs is as following: ``` 1. losetup /dev/loop1 bcachefs.img 2. ./bcachefs format /dev/loop1 3. mount -t bcachefs /dev/loop1 /mnt/bcachefs/ 4. ./mount-idmapped --map-mount b:0:1000:1 /mnt/bcachefs /mnt/idmapped1/ ll /mnt/bcachefs total 2 drwx------. 2 root root 0 Jun 14 14:10 lost+found -rw-r--r--. 1 root root 1945 Jun 14 14:12 profile ll /mnt/idmapped1/ total 2 drwx------. 2 1000 1000 0 Jun 14 14:10 lost+found -rw-r--r--. 1 1000 1000 1945 Jun 14 14:12 profile Signed-off-by: Hongbo Li <lihongbo22@xxxxxxxxxx> --- v2: - fix the gid translation when umask S_ISGID v1: - https://lore.kernel.org/all/20240615102038.3110867-1-lihongbo22@xxxxxxxxxx/T/ --- fs/bcachefs/fs.c | 50 ++++++++++++++++++++++++++++++++---------------- 1 file changed, 34 insertions(+), 16 deletions(-) diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c index c50457ba808d..0fcab802d376 100644 --- a/fs/bcachefs/fs.c +++ b/fs/bcachefs/fs.c @@ -350,6 +350,8 @@ __bch2_create(struct mnt_idmap *idmap, subvol_inum inum; struct bch_subvolume subvol; u64 journal_seq = 0; + kuid_t kuid; + kgid_t kgid; int ret; /* @@ -376,13 +378,15 @@ __bch2_create(struct mnt_idmap *idmap, retry: bch2_trans_begin(trans); + kuid = mapped_fsuid(idmap, i_user_ns(&dir->v)); + kgid = mapped_fsgid(idmap, i_user_ns(&dir->v)); ret = bch2_subvol_is_ro_trans(trans, dir->ei_inum.subvol) ?: bch2_create_trans(trans, inode_inum(dir), &dir_u, &inode_u, !(flags & BCH_CREATE_TMPFILE) ? &dentry->d_name : NULL, - from_kuid(i_user_ns(&dir->v), current_fsuid()), - from_kgid(i_user_ns(&dir->v), current_fsgid()), + from_kuid(i_user_ns(&dir->v), kuid), + from_kgid(i_user_ns(&dir->v), kgid), mode, rdev, default_acl, acl, snapshot_src, flags) ?: bch2_quota_acct(c, bch_qid(&inode_u), Q_INO, 1, @@ -800,11 +804,17 @@ static void bch2_setattr_copy(struct mnt_idmap *idmap, { struct bch_fs *c = inode->v.i_sb->s_fs_info; unsigned int ia_valid = attr->ia_valid; + kuid_t kuid; + kgid_t kgid; - if (ia_valid & ATTR_UID) - bi->bi_uid = from_kuid(i_user_ns(&inode->v), attr->ia_uid); - if (ia_valid & ATTR_GID) - bi->bi_gid = from_kgid(i_user_ns(&inode->v), attr->ia_gid); + if (ia_valid & ATTR_UID) { + kuid = from_vfsuid(idmap, i_user_ns(&inode->v), attr->ia_vfsuid); + bi->bi_uid = from_kuid(i_user_ns(&inode->v), kuid); + } + if (ia_valid & ATTR_GID) { + kgid = from_vfsgid(idmap, i_user_ns(&inode->v), attr->ia_vfsgid); + bi->bi_gid = from_kgid(i_user_ns(&inode->v), kgid); + } if (ia_valid & ATTR_SIZE) bi->bi_size = attr->ia_size; @@ -819,11 +829,11 @@ static void bch2_setattr_copy(struct mnt_idmap *idmap, if (ia_valid & ATTR_MODE) { umode_t mode = attr->ia_mode; kgid_t gid = ia_valid & ATTR_GID - ? attr->ia_gid + ? kgid : inode->v.i_gid; - if (!in_group_p(gid) && - !capable_wrt_inode_uidgid(idmap, &inode->v, CAP_FSETID)) + if (!in_group_or_capable(idmap, &inode->v, + make_vfsgid(idmap, i_user_ns(&inode->v), gid))) mode &= ~S_ISGID; bi->bi_mode = mode; } @@ -839,17 +849,23 @@ int bch2_setattr_nonsize(struct mnt_idmap *idmap, struct btree_iter inode_iter = { NULL }; struct bch_inode_unpacked inode_u; struct posix_acl *acl = NULL; + kuid_t kuid; + kgid_t kgid; int ret; mutex_lock(&inode->ei_update_lock); qid = inode->ei_qid; - if (attr->ia_valid & ATTR_UID) - qid.q[QTYP_USR] = from_kuid(i_user_ns(&inode->v), attr->ia_uid); + if (attr->ia_valid & ATTR_UID) { + kuid = from_vfsuid(idmap, i_user_ns(&inode->v), attr->ia_vfsuid); + qid.q[QTYP_USR] = from_kuid(i_user_ns(&inode->v), kuid); + } - if (attr->ia_valid & ATTR_GID) - qid.q[QTYP_GRP] = from_kgid(i_user_ns(&inode->v), attr->ia_gid); + if (attr->ia_valid & ATTR_GID) { + kgid = from_vfsgid(idmap, i_user_ns(&inode->v), attr->ia_vfsgid); + qid.q[QTYP_GRP] = from_kgid(i_user_ns(&inode->v), kgid); + } ret = bch2_fs_quota_transfer(c, inode, qid, ~0, KEY_TYPE_QUOTA_PREALLOC); @@ -905,13 +921,15 @@ static int bch2_getattr(struct mnt_idmap *idmap, { struct bch_inode_info *inode = to_bch_ei(d_inode(path->dentry)); struct bch_fs *c = inode->v.i_sb->s_fs_info; + vfsuid_t vfsuid = i_uid_into_vfsuid(idmap, &inode->v); + vfsgid_t vfsgid = i_gid_into_vfsgid(idmap, &inode->v); stat->dev = inode->v.i_sb->s_dev; stat->ino = inode->v.i_ino; stat->mode = inode->v.i_mode; stat->nlink = inode->v.i_nlink; - stat->uid = inode->v.i_uid; - stat->gid = inode->v.i_gid; + stat->uid = vfsuid_into_kuid(vfsuid); + stat->gid = vfsgid_into_kgid(vfsgid); stat->rdev = inode->v.i_rdev; stat->size = i_size_read(&inode->v); stat->atime = inode_get_atime(&inode->v); @@ -2169,7 +2187,7 @@ static struct file_system_type bcache_fs_type = { .name = "bcachefs", .init_fs_context = bch2_init_fs_context, .kill_sb = bch2_kill_sb, - .fs_flags = FS_REQUIRES_DEV, + .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP, }; MODULE_ALIAS_FS("bcachefs"); -- 2.34.1
