fs/fuse: convert to use invalid_mnt_idmap

We should convert fs/fuse code to use a newly introduced
invalid_mnt_idmap instead of passing a NULL as idmap pointer.

Suggested-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 317d2b3..cdf925e 100644 (file)
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -114,7 +114,11 @@ static struct fuse_req *fuse_get_req(struct mnt_idmap *idmap,
 {
        struct fuse_conn *fc = fm->fc;
        struct fuse_req *req;
+       bool no_idmap = !fm->sb || (fm->sb->s_iflags & SB_I_NOIDMAP);
+       kuid_t fsuid;
+       kgid_t fsgid;
        int err;
+
        atomic_inc(&fc->num_waiting);
 
        if (fuse_block_alloc(fc, for_background)) {
@@ -148,29 +152,24 @@ static struct fuse_req *fuse_get_req(struct mnt_idmap *idmap,
        if (for_background)
                __set_bit(FR_BACKGROUND, &req->flags);
 
-       if (!fm->sb || (fm->sb->s_iflags & SB_I_NOIDMAP) || idmap) {
-               kuid_t idmapped_fsuid;
-               kgid_t idmapped_fsgid;
+       /*
+        * Keep the old behavior when idmappings support was not
+        * declared by a FUSE server.
+        *
+        * For those FUSE servers who support idmapped mounts,
+        * we send UID/GID only along with "inode creation"
+        * fuse requests, otherwise idmap == &invalid_mnt_idmap and
+        * req->in.h.{u,g}id will be equal to FUSE_INVALID_UIDGID.
+        */
+       fsuid = no_idmap ? current_fsuid() : mapped_fsuid(idmap, fc->user_ns);
+       fsgid = no_idmap ? current_fsgid() : mapped_fsgid(idmap, fc->user_ns);
+       req->in.h.uid = from_kuid(fc->user_ns, fsuid);
+       req->in.h.gid = from_kgid(fc->user_ns, fsgid);
 
-               /*
-                * Note, that when
-                * (fm->sb->s_iflags & SB_I_NOIDMAP) is true, then
-                * (idmap == &nop_mnt_idmap) is always true and therefore,
-                * mapped_fsuid(idmap, fc->user_ns) == current_fsuid().
-                */
-               idmapped_fsuid = idmap ? mapped_fsuid(idmap, fc->user_ns) : current_fsuid();
-               idmapped_fsgid = idmap ? mapped_fsgid(idmap, fc->user_ns) : current_fsgid();
-               req->in.h.uid = from_kuid(fc->user_ns, idmapped_fsuid);
-               req->in.h.gid = from_kgid(fc->user_ns, idmapped_fsgid);
-
-               if (unlikely(req->in.h.uid == ((uid_t)-1) ||
-                            req->in.h.gid == ((gid_t)-1))) {
-                       fuse_put_request(req);
-                       return ERR_PTR(-EOVERFLOW);
-               }
-       } else {
-               req->in.h.uid = FUSE_INVALID_UIDGID;
-               req->in.h.gid = FUSE_INVALID_UIDGID;
+       if (no_idmap && unlikely(req->in.h.uid == ((uid_t)-1) ||
+                                req->in.h.gid == ((gid_t)-1))) {
+               fuse_put_request(req);
+               return ERR_PTR(-EOVERFLOW);
        }
 
        return req;
@@ -619,7 +618,7 @@ int fuse_simple_background(struct fuse_mount *fm, struct fuse_args *args,
                __set_bit(FR_BACKGROUND, &req->flags);
        } else {
                WARN_ON(args->nocreds);
-               req = fuse_get_req(NULL, fm, true);
+               req = fuse_get_req(&invalid_mnt_idmap, fm, true);
                if (IS_ERR(req))
                        return PTR_ERR(req);
        }
@@ -641,7 +640,7 @@ static int fuse_simple_notify_reply(struct fuse_mount *fm,
        struct fuse_req *req;
        struct fuse_iqueue *fiq = &fm->fc->iq;
 
-       req = fuse_get_req(NULL, fm, false);
+       req = fuse_get_req(&invalid_mnt_idmap, fm, false);
        if (IS_ERR(req))
                return PTR_ERR(req);
 

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 491e112..54104dd 100644 (file)
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1093,7 +1093,7 @@ static int fuse_rename2(struct mnt_idmap *idmap, struct inode *olddir,
                if (fc->no_rename2 || fc->minor < 23)
                        return -EINVAL;
 
-               err = fuse_rename_common((flags & RENAME_WHITEOUT) ? idmap : NULL,
+               err = fuse_rename_common((flags & RENAME_WHITEOUT) ? idmap : &invalid_mnt_idmap,
                                         olddir, oldent, newdir, newent, flags,
                                         FUSE_RENAME2,
                                         sizeof(struct fuse_rename2_in));
@@ -1102,7 +1102,7 @@ static int fuse_rename2(struct mnt_idmap *idmap, struct inode *olddir,
                        err = -EINVAL;
                }
        } else {
-               err = fuse_rename_common(NULL, olddir, oldent, newdir, newent, 0,
+               err = fuse_rename_common(&invalid_mnt_idmap, olddir, oldent, newdir, newent, 0,
                                         FUSE_RENAME,
                                         sizeof(struct fuse_rename_in));
        }
@@ -1127,7 +1127,7 @@ static int fuse_link(struct dentry *entry, struct inode *newdir,
        args.in_args[0].value = &inarg;
        args.in_args[1].size = newent->d_name.len + 1;
        args.in_args[1].value = newent->d_name.name;
-       err = create_new_entry(NULL, fm, &args, newdir, newent, inode->i_mode);
+       err = create_new_entry(&invalid_mnt_idmap, fm, &args, newdir, newent, inode->i_mode);
        if (!err)
                fuse_update_ctime_in_cache(inode);
        else if (err == -EINTR)

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index b2c7834..e6cc3d5 100644 (file)
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -1153,7 +1153,7 @@ ssize_t __fuse_simple_request(struct mnt_idmap *idmap,
 
 static inline ssize_t fuse_simple_request(struct fuse_mount *fm, struct fuse_args *args)
 {
-       return __fuse_simple_request(NULL, fm, args);
+       return __fuse_simple_request(&invalid_mnt_idmap, fm, args);
 }
 
 static inline ssize_t fuse_simple_idmap_request(struct mnt_idmap *idmap,