diff options
| -rw-r--r-- | fs/fuse/dir.c | 78 | ||||
| -rw-r--r-- | fs/fuse/fuse_i.h | 3 | ||||
| -rw-r--r-- | fs/fuse/inode.c | 26 | ||||
| -rw-r--r-- | fs/fuse/virtio_fs.c | 1 |
4 files changed, 105 insertions, 3 deletions
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index c885d9b60263..ff7dbeb16f88 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -10,6 +10,7 @@ #include <linux/pagemap.h> #include <linux/file.h> +#include <linux/fs_context.h> #include <linux/sched.h> #include <linux/namei.h> #include <linux/slab.h> @@ -237,7 +238,8 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags) ret = -ENOENT; if (!ret) { fi = get_fuse_inode(inode); - if (outarg.nodeid != get_node_id(inode)) { + if (outarg.nodeid != get_node_id(inode) || + (bool) IS_AUTOMOUNT(inode) != (bool) (outarg.attr.flags & FUSE_ATTR_SUBMOUNT)) { fuse_queue_forget(fm->fc, forget, outarg.nodeid, 1); goto invalid; @@ -299,6 +301,79 @@ static int fuse_dentry_delete(const struct dentry *dentry) return time_before64(fuse_dentry_time(dentry), get_jiffies_64()); } +/* + * Create a fuse_mount object with a new superblock (with path->dentry + * as the root), and return that mount so it can be auto-mounted on + * @path. + */ +static struct vfsmount *fuse_dentry_automount(struct path *path) +{ + struct fs_context *fsc; + struct fuse_mount *parent_fm = get_fuse_mount_super(path->mnt->mnt_sb); + struct fuse_conn *fc = parent_fm->fc; + struct fuse_mount *fm; + struct vfsmount *mnt; + struct fuse_inode *mp_fi = get_fuse_inode(d_inode(path->dentry)); + struct super_block *sb; + int err; + + fsc = fs_context_for_submount(path->mnt->mnt_sb->s_type, path->dentry); + if (IS_ERR(fsc)) { + err = PTR_ERR(fsc); + goto out; + } + + err = -ENOMEM; + fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL); + if (!fm) + goto out_put_fsc; + + refcount_set(&fm->count, 1); + fsc->s_fs_info = fm; + sb = sget_fc(fsc, NULL, set_anon_super_fc); + if (IS_ERR(sb)) { + err = PTR_ERR(sb); + fuse_mount_put(fm); + goto out_put_fsc; + } + fm->fc = fuse_conn_get(fc); + + /* Initialize superblock, making @mp_fi its root */ + err = fuse_fill_super_submount(sb, mp_fi); + if (err) + goto out_put_sb; + + sb->s_flags |= SB_ACTIVE; + fsc->root = dget(sb->s_root); + /* We are done configuring the superblock, so unlock it */ + up_write(&sb->s_umount); + + down_write(&fc->killsb); + list_add_tail(&fm->fc_entry, &fc->mounts); + up_write(&fc->killsb); + + /* Create the submount */ + mnt = vfs_create_mount(fsc); + if (IS_ERR(mnt)) { + err = PTR_ERR(mnt); + goto out_put_fsc; + } + mntget(mnt); + put_fs_context(fsc); + return mnt; + +out_put_sb: + /* + * Only jump here when fsc->root is NULL and sb is still locked + * (otherwise put_fs_context() will put the superblock) + */ + deactivate_locked_super(sb); +out_put_fsc: + put_fs_context(fsc); +out: + return ERR_PTR(err); +} + const struct dentry_operations fuse_dentry_operations = { .d_revalidate = fuse_dentry_revalidate, .d_delete = fuse_dentry_delete, @@ -306,6 +381,7 @@ const struct dentry_operations fuse_dentry_operations = { .d_init = fuse_dentry_init, .d_release = fuse_dentry_release, #endif + .d_automount = fuse_dentry_automount, }; const struct dentry_operations fuse_root_dentry_operations = { diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index d469905166ab..d51598017d13 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -742,6 +742,9 @@ struct fuse_conn { /** Do not allow MNT_FORCE umount */ unsigned int no_force_umount:1; + /* Auto-mount submounts announced by the server */ + unsigned int auto_submounts:1; + /** The number of requests waiting for completion */ atomic_t num_waiting; diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index da5f03f910cf..7eceb0f20c93 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -309,7 +309,26 @@ struct inode *fuse_iget(struct super_block *sb, u64 nodeid, struct fuse_inode *fi; struct fuse_conn *fc = get_fuse_conn_super(sb); - retry: + /* + * Auto mount points get their node id from the submount root, which is + * not a unique identifier within this filesystem. + * + * To avoid conflicts, do not place submount points into the inode hash + * table. + */ + if (fc->auto_submounts && (attr->flags & FUSE_ATTR_SUBMOUNT) && + S_ISDIR(attr->mode)) { + inode = new_inode(sb); + if (!inode) + return NULL; + + fuse_init_inode(inode, attr); + get_fuse_inode(inode)->nodeid = nodeid; + inode->i_flags |= S_AUTOMOUNT; + goto done; + } + +retry: inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid); if (!inode) return NULL; @@ -327,7 +346,7 @@ struct inode *fuse_iget(struct super_block *sb, u64 nodeid, iput(inode); goto retry; } - +done: fi = get_fuse_inode(inode); spin_lock(&fi->lock); fi->nlookup++; @@ -1083,6 +1102,9 @@ void fuse_send_init(struct fuse_mount *fm) if (fm->fc->dax) ia->in.flags |= FUSE_MAP_ALIGNMENT; #endif + if (fm->fc->auto_submounts) + ia->in.flags |= FUSE_SUBMOUNTS; + ia->args.opcode = FUSE_INIT; ia->args.in_numargs = 1; ia->args.in_args[0].size = sizeof(ia->in); diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c index 746fa1a40975..5200ad50ed10 100644 --- a/fs/fuse/virtio_fs.c +++ b/fs/fuse/virtio_fs.c @@ -1431,6 +1431,7 @@ static int virtio_fs_get_tree(struct fs_context *fsc) &virtio_fs_fiq_ops, fs); fc->release = fuse_free_conn; fc->delete_stale = true; + fc->auto_submounts = true; fsc->s_fs_info = fm; sb = sget_fc(fsc, virtio_fs_test_super, virtio_fs_set_super); |