/* FUSE: Filesystem in Userspace Copyright (C) 2001-2008 Miklos Szeredi This program can be distributed under the terms of the GNU GPL. See the file COPYING. */ #include "fuse_i.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include MODULE_AUTHOR("Miklos Szeredi "); MODULE_DESCRIPTION("Filesystem in Userspace"); MODULE_LICENSE("GPL"); static struct kmem_cache *fuse_inode_cachep; struct list_head fuse_conn_list; DEFINE_MUTEX(fuse_mutex); static int set_global_limit(const char *val, const struct kernel_param *kp); unsigned max_user_bgreq; module_param_call(max_user_bgreq, set_global_limit, param_get_uint, &max_user_bgreq, 0644); __MODULE_PARM_TYPE(max_user_bgreq, "uint"); MODULE_PARM_DESC(max_user_bgreq, "Global limit for the maximum number of backgrounded requests an " "unprivileged user can set"); unsigned max_user_congthresh; module_param_call(max_user_congthresh, set_global_limit, param_get_uint, &max_user_congthresh, 0644); __MODULE_PARM_TYPE(max_user_congthresh, "uint"); MODULE_PARM_DESC(max_user_congthresh, "Global limit for the maximum congestion threshold an " "unprivileged user can set"); #define FUSE_DEFAULT_BLKSIZE 512 /** Maximum number of outstanding background requests */ #define FUSE_DEFAULT_MAX_BACKGROUND 12 /** Congestion starts at 75% of maximum */ #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4) #ifdef CONFIG_BLOCK static struct file_system_type fuseblk_fs_type; #endif struct fuse_forget_link *fuse_alloc_forget(void) { return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT); } static struct inode *fuse_alloc_inode(struct super_block *sb) { struct fuse_inode *fi; fi = alloc_inode_sb(sb, fuse_inode_cachep, GFP_KERNEL); if (!fi) return NULL; fi->i_time = 0; fi->inval_mask = 0; fi->nodeid = 0; fi->nlookup = 0; fi->attr_version = 0; fi->orig_ino = 0; fi->state = 0; mutex_init(&fi->mutex); spin_lock_init(&fi->lock); fi->forget = fuse_alloc_forget(); if (!fi->forget) goto out_free; if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi)) goto out_free_forget; return &fi->inode; out_free_forget: kfree(fi->forget); out_free: kmem_cache_free(fuse_inode_cachep, fi); return NULL; } static void fuse_free_inode(struct inode *inode) { struct fuse_inode *fi = get_fuse_inode(inode); mutex_destroy(&fi->mutex); kfree(fi->forget); #ifdef CONFIG_FUSE_DAX kfree(fi->dax); #endif kmem_cache_free(fuse_inode_cachep, fi); } static void fuse_evict_inode(struct inode *inode) { struct fuse_inode *fi = get_fuse_inode(inode); /* Will write inode on close/munmap and in all other dirtiers */ WARN_ON(inode->i_state & I_DIRTY_INODE); truncate_inode_pages_final(&inode->i_data); clear_inode(inode); if (inode->i_sb->s_flags & SB_ACTIVE) { struct fuse_conn *fc = get_fuse_conn(inode); if (FUSE_IS_DAX(inode)) fuse_dax_inode_cleanup(inode); if (fi->nlookup) { fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup); fi->forget = NULL; } } if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) { WARN_ON(!list_empty(&fi->write_files)); WARN_ON(!list_empty(&fi->queued_writes)); } } static int fuse_reconfigure(struct fs_context *fsc) { struct super_block *sb = fsc->root->d_sb; sync_filesystem(sb); if (fsc->sb_flags & SB_MANDLOCK) return -EINVAL; return 0; } /* * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down * so that it will fit. */ static ino_t fuse_squash_ino(u64 ino64) { ino_t ino = (ino_t) ino64; if (sizeof(ino_t) < sizeof(u64)) ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8; return ino; } void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, u64 attr_valid, u32 cache_mask) { struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_inode *fi = get_fuse_inode(inode); lockdep_assert_held(&fi->lock); fi->attr_version = atomic64_inc_return(&fc->attr_version); fi->i_time = attr_valid; WRITE_ONCE(fi->inval_mask, 0); inode->i_ino = fuse_squash_ino(attr->ino); inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777); set_nlink(inode, attr->nlink); inode->i_uid = make_kuid(fc->user_ns, attr->uid); inode->i_gid = make_kgid(fc->user_ns, attr->gid); inode->i_blocks = attr->blocks; /* Sanitize nsecs */ attr->atimensec = min_t(u32, attr->atimensec, NSEC_PER_SEC - 1); attr->mtimensec = min_t(u32, attr->mtimensec, NSEC_PER_SEC - 1); attr->ctimensec = min_t(u32, attr->ctimensec, NSEC_PER_SEC - 1); inode->i_atime.tv_sec = attr->atime; inode->i_atime.tv_nsec = attr->atimensec; /* mtime from server may be stale due to local buffered write */ if (!(cache_mask & STATX_MTIME)) { inode->i_mtime.tv_sec = attr->mtime; inode->i_mtime.tv_nsec = attr->mtimensec; } if (!(cache_mask & STATX_CTIME)) { inode->i_ctime.tv_sec = attr->ctime; inode->i_ctime.tv_nsec = attr->ctimensec; } if (attr->blksize != 0) inode->i_blkbits = ilog2(attr->blksize); else inode->i_blkbits = inode->i_sb->s_blocksize_bits; /* * Don't set the sticky bit in i_mode, unless we want the VFS * to check permissions. This prevents failures due to the * check in may_delete(). */ fi->orig_i_mode = inode->i_mode; if (!fc->default_permissions) inode->i_mode &= ~S_ISVTX; fi->orig_ino = attr->ino; /* * We are refreshing inode data and it is possible that another * client set suid/sgid or security.capability xattr. So clear * S_NOSEC. Ideally, we could have cleared it only if suid/sgid * was set or if security.capability xattr was set. But we don't * know if security.capability has been set or not. So clear it * anyway. Its less efficient but should be safe. */ inode->i_flags &= ~S_NOSEC; } u32 fuse_get_cache_mask(struct inode *inode) { struct fuse_conn *fc = get_fuse_conn(inode); if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) return 0; return STATX_MTIME | STATX_CTIME | STATX_SIZE; } void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, u64 attr_valid, u64 attr_version) { struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_inode *fi = get_fuse_inode(inode); u32 cache_mask; loff_t oldsize; struct timespec64 old_mtime; spin_lock(&fi->lock); /* * In case of writeback_cache enabled, writes update mtime, ctime and * may update i_size. In these cases trust the cached value in the * inode. */ cache_mask = fuse_get_cache_mask(inode); if (cache_mask & STATX_SIZE) attr->size = i_size_read(inode); if (cache_mask & STATX_MTIME) { attr->mtime = inode->i_mtime.tv_sec; attr->mtimensec = inode->i_mtime.tv_nsec; } if (cache_mask & STATX_CTIME) { attr->ctime = inode->i_ctime.tv_sec; attr->ctimensec = inode->i_ctime.tv_nsec; } if ((attr_version != 0 && fi->attr_version > attr_version) || test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) { spin_unlock(&fi->lock); return; } old_mtime = inode->i_mtime; fuse_change_attributes_common(inode, attr, attr_valid, cache_mask); oldsize = inode->i_size; /* * In case of writeback_cache enabled, the cached writes beyond EOF * extend local i_size without keeping userspace server in sync. So, * attr->size coming from server can be stale. We cannot trust it. */ if (!(cache_mask & STATX_SIZE)) i_size_write(inode, attr->size); spin_unlock(&fi->lock); if (!cache_mask && S_ISREG(inode->i_mode)) { bool inval = false; if (oldsize != attr->size) { truncate_pagecache(inode, attr->size); if (!fc->explicit_inval_data) inval = true; } else if (fc->auto_inval_data) { struct timespec64 new_mtime = { .tv_sec = attr->mtime, .tv_nsec = attr->mtimensec, }; /* * Auto inval mode also checks and invalidates if mtime * has changed. */ if (!timespec64_equal(&old_mtime, &new_mtime)) inval = true; } if (inval) invalidate_inode_pages2(inode->i_mapping); } if (IS_ENABLED(CONFIG_FUSE_DAX)) fuse_dax_dontcache(inode, attr->flags); } static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr) { inode->i_mode = attr->mode & S_IFMT; inode->i_size = attr->size; inode->i_mtime.tv_sec = attr->mtime; inode->i_mtime.tv_nsec = attr->mtimensec; inode->i_ctime.tv_sec = attr->ctime; inode->i_ctime.tv_nsec = attr->ctimensec; if (S_ISREG(inode->i_mode)) { fuse_init_common(inode); fuse_init_file_inode(inode, attr->flags); } else if (S_ISDIR(inode->i_mode)) fuse_init_dir(inode); else if (S_ISLNK(inode->i_mode)) fuse_init_symlink(inode); else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { fuse_init_common(inode); init_special_inode(inode, inode->i_mode, new_decode_dev(attr->rdev)); } else BUG(); } static int fuse_inode_eq(struct inode *inode, void *_nodeidp) { u64 nodeid = *(u64 *) _nodeidp; if (get_node_id(inode) == nodeid) return 1; else return 0; } static int fuse_inode_set(struct inode *inode, void *_nodeidp) { u64 nodeid = *(u64 *) _nodeidp; get_fuse_inode(inode)->nodeid = nodeid; return 0; } struct inode *fuse_iget(struct super_block *sb, u64 nodeid, int generation, struct fuse_attr *attr, u64 attr_valid, u64 attr_version) { struct inode *inode; struct fuse_inode *fi; struct fuse_conn *fc = get_fuse_conn_super(sb); /* * 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; if ((inode->i_state & I_NEW)) { inode->i_flags |= S_NOATIME; if (!fc->writeback_cache || !S_ISREG(attr->mode)) inode->i_flags |= S_NOCMTIME; inode->i_generation = generation; fuse_init_inode(inode, attr); unlock_new_inode(inode); } else if (fuse_stale_inode(inode, generation, attr)) { /* nodeid was reused, any I/O on the old inode should fail */ fuse_make_bad(inode); iput(inode); goto retry; } done: fi = get_fuse_inode(inode); spin_lock(&fi->lock); fi->nlookup++; spin_unlock(&fi->lock); fuse_change_attributes(inode, attr, attr_valid, attr_version); return inode; } struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid, struct fuse_mount **fm) { struct fuse_mount *fm_iter; struct inode *inode; WARN_ON(!rwsem_is_locked(&fc->killsb)); list_for_each_entry(fm_iter, &fc->mounts, fc_entry) { if (!fm_iter->sb) continue; inode = ilookup5(fm_iter->sb, nodeid, fuse_inode_eq, &nodeid); if (inode) { if (fm) *fm = fm_iter; return inode; } } return NULL; } int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid, loff_t offset, loff_t len) { struct fuse_inode *fi; struct inode *inode; pgoff_t pg_start; pgoff_t pg_end; inode = fuse_ilookup(fc, nodeid, NULL); if (!inode) return -ENOENT; fi = get_fuse_inode(inode); spin_lock(&fi->lock); fi->attr_version = atomic64_inc_return(&fc->attr_version); spin_unlock(&fi->lock); fuse_invalidate_attr(inode); forget_all_cached_acls(inode); if (offset >= 0) { pg_start = offset >> PAGE_SHIFT; if (len <= 0) pg_end = -1; else pg_end = (offset + len - 1) >> PAGE_SHIFT; invalidate_inode_pages2_range(inode->i_mapping, pg_start, pg_end); } iput(inode); return 0; } bool fuse_lock_inode(struct inode *inode) { bool locked = false; if (!get_fuse_conn(inode)->parallel_dirops) { mutex_lock(&get_fuse_inode(inode)->mutex); locked = true; } return locked; } void fuse_unlock_inode(struct inode *inode, bool locked) { if (locked) mutex_unlock(&get_fuse_inode(inode)->mutex); } static void fuse_umount_begin(struct super_block *sb) { struct fuse_conn *fc = get_fuse_conn_super(sb); if (fc->no_force_umount) return; fuse_abort_conn(fc); // Only retire block-device-based superblocks. if (sb->s_bdev != NULL) retire_super(sb); } static void fuse_send_destroy(struct fuse_mount *fm) { if (fm->fc->conn_init) { FUSE_ARGS(args); args.opcode = FUSE_DESTROY; args.force = true; args.nocreds = true; fuse_simple_request(fm, &args); } } static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) { stbuf->f_type = FUSE_SUPER_MAGIC; stbuf->f_bsize = attr->bsize; stbuf->f_frsize = attr->frsize; stbuf->f_blocks = attr->blocks; stbuf->f_bfree = attr->bfree; stbuf->f_bavail = attr->bavail; stbuf->f_files = attr->files; stbuf->f_ffree = attr->ffree; stbuf->f_namelen = attr->namelen; /* fsid is left zero */ } static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf) { struct super_block *sb = dentry->d_sb; struct fuse_mount *fm = get_fuse_mount_super(sb); FUSE_ARGS(args); struct fuse_statfs_out outarg; int err; if (!fuse_allow_current_process(fm->fc)) { buf->f_type = FUSE_SUPER_MAGIC; return 0; } memset(&outarg, 0, sizeof(outarg)); args.in_numargs = 0; args.opcode = FUSE_STATFS; args.nodeid = get_node_id(d_inode(dentry)); args.out_numargs = 1; args.out_args[0].size = sizeof(outarg); args.out_args[0].value = &outarg; err = fuse_simple_request(fm, &args); if (!err) convert_fuse_statfs(buf, &outarg.st); return err; } static struct fuse_sync_bucket *fuse_sync_bucket_alloc(void) { struct fuse_sync_bucket *bucket; bucket = kzalloc(sizeof(*bucket), GFP_KERNEL | __GFP_NOFAIL); if (bucket) { init_waitqueue_head(&bucket->waitq); /* Initial active count */ atomic_set(&bucket->count, 1); } return bucket; } static void fuse_sync_fs_writes(struct fuse_conn *fc) { struct fuse_sync_bucket *bucket, *new_bucket; int count; new_bucket = fuse_sync_bucket_alloc(); spin_lock(&fc->lock); bucket = rcu_dereference_protected(fc->curr_bucket, 1); count = atomic_read(&bucket->count); WARN_ON(count < 1); /* No outstanding writes? */ if (count == 1) { spin_unlock(&fc->lock); kfree(new_bucket); return; } /* * Completion of new bucket depends on completion of this bucket, so add * one more count. */ atomic_inc(&new_bucket->count); rcu_assign_pointer(fc->curr_bucket, new_bucket); spin_unlock(&fc->lock); /* * Drop initial active count. At this point if all writes in this and * ancestor buckets complete, the count will go to zero and this task * will be woken up. */ atomic_dec(&bucket->count); wait_event(bucket->waitq, atomic_read(&bucket->count) == 0); /* Drop temp count on descendant bucket */ fuse_sync_bucket_dec(new_bucket); kfree_rcu(bucket, rcu); } static int fuse_sync_fs(struct super_block *sb, int wait) { struct fuse_mount *fm = get_fuse_mount_super(sb); struct fuse_conn *fc = fm->fc; struct fuse_syncfs_in inarg; FUSE_ARGS(args); int err; /* * Userspace cannot handle the wait == 0 case. Avoid a * gratuitous roundtrip. */ if (!wait) return 0; /* The filesystem is being unmounted. Nothing to do. */ if (!sb->s_root) return 0; if (!fc->sync_fs) return 0; fuse_sync_fs_writes(fc); memset(&inarg, 0, sizeof(inarg)); args.in_numargs = 1; args.in_args[0].size = sizeof(inarg); args.in_args[0].value = &inarg; args.opcode = FUSE_SYNCFS; args.nodeid = get_node_id(sb->s_root->d_inode); args.out_numargs = 0; err = fuse_simple_request(fm, &args); if (err == -ENOSYS) { fc->sync_fs = 0; err = 0; } return err; } enum { OPT_SOURCE, OPT_SUBTYPE, OPT_FD, OPT_ROOTMODE, OPT_USER_ID, OPT_GROUP_ID, OPT_DEFAULT_PERMISSIONS, OPT_ALLOW_OTHER, OPT_MAX_READ, OPT_BLKSIZE, OPT_ERR }; static const struct fs_parameter_spec fuse_fs_parameters[] = { fsparam_string ("source", OPT_SOURCE), fsparam_u32 ("fd", OPT_FD), fsparam_u32oct ("rootmode", OPT_ROOTMODE), fsparam_u32 ("user_id", OPT_USER_ID), fsparam_u32 ("group_id", OPT_GROUP_ID), fsparam_flag ("default_permissions", OPT_DEFAULT_PERMISSIONS), fsparam_flag ("allow_other", OPT_ALLOW_OTHER), fsparam_u32 ("max_read", OPT_MAX_READ), fsparam_u32 ("blksize", OPT_BLKSIZE), fsparam_string ("subtype", OPT_SUBTYPE), {} }; static int fuse_parse_param(struct fs_context *fsc, struct fs_parameter *param) { struct fs_parse_result result; struct fuse_fs_context *ctx = fsc->fs_private; int opt; if (fsc->purpose == FS_CONTEXT_FOR_RECONFIGURE) { /* * Ignore options coming from mount(MS_REMOUNT) for backward * compatibility. */ if (fsc->oldapi) return 0; return invalfc(fsc, "No changes allowed in reconfigure"); } opt = fs_parse(fsc, fuse_fs_parameters, param, &result); if (opt < 0) return opt; switch (opt) { case OPT_SOURCE: if (fsc->source) return invalfc(fsc, "Multiple sources specified"); fsc->source = param->string; param->string = NULL; break; case OPT_SUBTYPE: if (ctx->subtype) return invalfc(fsc, "Multiple subtypes specified"); ctx->subtype = param->string; param->string = NULL; return 0; case OPT_FD: ctx->fd = result.uint_32; ctx->fd_present = true; break; case OPT_ROOTMODE: if (!fuse_valid_type(result.uint_32)) return invalfc(fsc, "Invalid rootmode"); ctx->rootmode = result.uint_32; ctx->rootmode_present = true; break; case OPT_USER_ID: ctx->user_id = make_kuid(fsc->user_ns, result.uint_32); if (!uid_valid(ctx->user_id)) return invalfc(fsc, "Invalid user_id"); ctx->user_id_present = true; break; case OPT_GROUP_ID: ctx->group_id = make_kgid(fsc->user_ns, result.uint_32); if (!gid_valid(ctx->group_id)) return invalfc(fsc, "Invalid group_id"); ctx->group_id_present = true; break; case OPT_DEFAULT_PERMISSIONS: ctx->default_permissions = true; break; case OPT_ALLOW_OTHER: ctx->allow_other = true; break; case OPT_MAX_READ: ctx->max_read = result.uint_32; break; case OPT_BLKSIZE: if (!ctx->is_bdev) return invalfc(fsc, "blksize only supported for fuseblk"); ctx->blksize = result.uint_32; break; default: return -EINVAL; } return 0; } static void fuse_free_fsc(struct fs_context *fsc) { struct fuse_fs_context *ctx = fsc->fs_private; if (ctx) { kfree(ctx->subtype); kfree(ctx); } } static int fuse_show_options(struct seq_file *m, struct dentry *root) { struct super_block *sb = root->d_sb; struct fuse_conn *fc = get_fuse_conn_super(sb); if (fc->legacy_opts_show) { seq_printf(m, ",user_id=%u", from_kuid_munged(fc->user_ns, fc->user_id)); seq_printf(m, ",group_id=%u", from_kgid_munged(fc->user_ns, fc->group_id)); if (fc->default_permissions) seq_puts(m, ",default_permissions"); if (fc->allow_other) seq_puts(m, ",allow_other"); if (fc->max_read != ~0) seq_printf(m, ",max_read=%u", fc->max_read); if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE) seq_printf(m, ",blksize=%lu", sb->s_blocksize); } #ifdef CONFIG_FUSE_DAX if (fc->dax_mode == FUSE_DAX_ALWAYS) seq_puts(m, ",dax=always"); else if (fc->dax_mode == FUSE_DAX_NEVER) seq_puts(m, ",dax=never"); else if (fc->dax_mode == FUSE_DAX_INODE_USER) seq_puts(m, ",dax=inode"); #endif return 0; } static void fuse_iqueue_init(struct fuse_iqueue *fiq, const struct fuse_iqueue_ops *ops, void *priv) { memset(fiq, 0, sizeof(struct fuse_iqueue)); spin_lock_init(&fiq->lock); init_waitqueue_head(&fiq->waitq); INIT_LIST_HEAD(&fiq->pending); INIT_LIST_HEAD(&fiq->interrupts); fiq->forget_list_tail = &fiq->forget_list_head; fiq->connected = 1; fiq->ops = ops; fiq->priv = priv; } static void fuse_pqueue_init(struct fuse_pqueue *fpq) { unsigned int i; spin_lock_init(&fpq->lock); for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) INIT_LIST_HEAD(&fpq->processing[i]); INIT_LIST_HEAD(&fpq->io); fpq->connected = 1; } void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm, struct user_namespace *user_ns, const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv) { memset(fc, 0, sizeof(*fc)); spin_lock_init(&fc->lock); spin_lock_init(&fc->bg_lock); init_rwsem(&fc->killsb); refcount_set(&fc->count, 1); atomic_set(&fc->dev_count, 1); init_waitqueue_head(&fc->blocked_waitq); fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv); INIT_LIST_HEAD(&fc->bg_queue); INIT_LIST_HEAD(&fc->entry); INIT_LIST_HEAD(&fc->devices); atomic_set(&fc->num_waiting, 0); fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND; fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD; atomic64_set(&fc->khctr, 0); fc->polled_files = RB_ROOT; fc->blocked = 0; fc->initialized = 0; fc->connected = 1; atomic64_set(&fc->attr_version, 1); get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); fc->pid_ns = get_pid_ns(task_active_pid_ns(current)); fc->user_ns = get_user_ns(user_ns); fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ; fc->max_pages_limit = FUSE_MAX_MAX_PAGES; INIT_LIST_HEAD(&fc->mounts); list_add(&fm->fc_entry, &fc->mounts); fm->fc = fc; } EXPORT_SYMBOL_GPL(fuse_conn_init); void fuse_conn_put(struct fuse_conn *fc) { if (refcount_dec_and_test(&fc->count)) { struct fuse_iqueue *fiq = &fc->iq; struct fuse_sync_bucket *bucket; if (IS_ENABLED(CONFIG_FUSE_DAX)) fuse_dax_conn_free(fc); if (fiq->ops->release) fiq->ops->release(fiq); put_pid_ns(fc->pid_ns); put_user_ns(fc->user_ns); bucket = rcu_dereference_protected(fc->curr_bucket, 1); if (bucket) { WARN_ON(atomic_read(&bucket->count) != 1); kfree(bucket); } fc->release(fc); } } EXPORT_SYMBOL_GPL(fuse_conn_put); struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) { refcount_inc(&fc->count); return fc; } EXPORT_SYMBOL_GPL(fuse_conn_get); static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode) { struct fuse_attr attr; memset(&attr, 0, sizeof(attr)); attr.mode = mode; attr.ino = FUSE_ROOT_ID; attr.nlink = 1; return fuse_iget(sb, 1, 0, &attr, 0, 0); } struct fuse_inode_handle { u64 nodeid; u32 generation; }; static struct dentry *fuse_get_dentry(struct super_block *sb, struct fuse_inode_handle *handle) { struct fuse_conn *fc = get_fuse_conn_super(sb); struct inode *inode; struct dentry *entry; int err = -ESTALE; if (handle->nodeid == 0) goto out_err; inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid); if (!inode) { struct fuse_entry_out outarg; const struct qstr name = QSTR_INIT(".", 1); if (!fc->export_support) goto out_err; err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg, &inode); if (err && err != -ENOENT) goto out_err; if (err || !inode) { err = -ESTALE; goto out_err; } err = -EIO; if (get_node_id(inode) != handle->nodeid) goto out_iput; } err = -ESTALE; if (inode->i_generation != handle->generation) goto out_iput; entry = d_obtain_alias(inode); if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) fuse_invalidate_entry_cache(entry); return entry; out_iput: iput(inode); out_err: return ERR_PTR(err); } static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len, struct inode *parent) { int len = parent ? 6 : 3; u64 nodeid; u32 generation; if (*max_len < len) { *max_len = len; return FILEID_INVALID; } nodeid = get_fuse_inode(inode)->nodeid; generation = inode->i_generation; fh[0] = (u32)(nodeid >> 32); fh[1] = (u32)(nodeid & 0xffffffff); fh[2] = generation; if (parent) { nodeid = get_fuse_inode(parent)->nodeid; generation = parent->i_generation; fh[3] = (u32)(nodeid >> 32); fh[4] = (u32)(nodeid & 0xffffffff); fh[5] = generation; } *max_len = len; return parent ? 0x82 : 0x81; } static struct dentry *fuse_fh_to_dentry(struct super_block *sb, struct fid *fid, int fh_len, int fh_type) { struct fuse_inode_handle handle; if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3) return NULL; handle.nodeid = (u64) fid->raw[0] << 32; handle.nodeid |= (u64) fid->raw[1]; handle.generation = fid->raw[2]; return fuse_get_dentry(sb, &handle); } static struct dentry *fuse_fh_to_parent(struct super_block *sb, struct fid *fid, int fh_len, int fh_type) { struct fuse_inode_handle parent; if (fh_type != 0x82 || fh_len < 6) return NULL; parent.nodeid = (u64) fid->raw[3] << 32; parent.nodeid |= (u64) fid->raw[4]; parent.generation = fid->raw[5]; return fuse_get_dentry(sb, &parent); } static struct dentry *fuse_get_parent(struct dentry *child) { struct inode *child_inode = d_inode(child); struct fuse_conn *fc = get_fuse_conn(child_inode); struct inode *inode; struct dentry *parent; struct fuse_entry_out outarg; int err; if (!fc->export_support) return ERR_PTR(-ESTALE); err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), &dotdot_name, &outarg, &inode); if (err) { if (err == -ENOENT) return ERR_PTR(-ESTALE); return ERR_PTR(err); } parent = d_obtain_alias(inode); if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) fuse_invalidate_entry_cache(parent); return parent; } static const struct export_operations fuse_export_operations = { .fh_to_dentry = fuse_fh_to_dentry, .fh_to_parent = fuse_fh_to_parent, .encode_fh = fuse_encode_fh, .get_parent = fuse_get_parent, }; static const struct super_operations fuse_super_operations = { .alloc_inode = fuse_alloc_inode, .free_inode = fuse_free_inode, .evict_inode = fuse_evict_inode, .write_inode = fuse_write_inode, .drop_inode = generic_delete_inode, .umount_begin = fuse_umount_begin, .statfs = fuse_statfs, .sync_fs = fuse_sync_fs, .show_options = fuse_show_options, }; static void sanitize_global_limit(unsigned *limit) { /* * The default maximum number of async requests is calculated to consume * 1/2^13 of the total memory, assuming 392 bytes per request. */ if (*limit == 0) *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392; if (*limit >= 1 << 16) *limit = (1 << 16) - 1; } static int set_global_limit(const char *val, const struct kernel_param *kp) { int rv; rv = param_set_uint(val, kp); if (rv) return rv; sanitize_global_limit((unsigned *)kp->arg); return 0; } static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg) { int cap_sys_admin = capable(CAP_SYS_ADMIN); if (arg->minor < 13) return; sanitize_global_limit(&max_user_bgreq); sanitize_global_limit(&max_user_congthresh); spin_lock(&fc->bg_lock); if (arg->max_background) { fc->max_background = arg->max_background; if (!cap_sys_admin && fc->max_background > max_user_bgreq) fc->max_background = max_user_bgreq; } if (arg->congestion_threshold) { fc->congestion_threshold = arg->congestion_threshold; if (!cap_sys_admin && fc->congestion_threshold > max_user_congthresh) fc->congestion_threshold = max_user_congthresh; } spin_unlock(&fc->bg_lock); } struct fuse_init_args { struct fuse_args args; struct fuse_init_in in; struct fuse_init_out out; }; static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args, int error) { struct fuse_conn *fc = fm->fc; struct fuse_init_args *ia = container_of(args, typeof(*ia), args); struct fuse_init_out *arg = &ia->out; bool ok = true; if (error || arg->major != FUSE_KERNEL_VERSION) ok = false; else { unsigned long ra_pages; process_init_limits(fc, arg); if (arg->minor >= 6) { u64 flags = arg->flags; if (flags & FUSE_INIT_EXT) flags |= (u64) arg->flags2 << 32; ra_pages = arg->max_readahead / PAGE_SIZE; if (flags & FUSE_ASYNC_READ) fc->async_read = 1; if (!(flags & FUSE_POSIX_LOCKS)) fc->no_lock = 1; if (arg->minor >= 17) { if (!(flags & FUSE_FLOCK_LOCKS)) fc->no_flock = 1; } else { if (!(flags & FUSE_POSIX_LOCKS)) fc->no_flock = 1; } if (flags & FUSE_ATOMIC_O_TRUNC) fc->atomic_o_trunc = 1; if (arg->minor >= 9) { /* LOOKUP has dependency on proto version */ if (flags & FUSE_EXPORT_SUPPORT) fc->export_support = 1; } if (flags & FUSE_BIG_WRITES) fc->big_writes = 1; if (flags & FUSE_DONT_MASK) fc->dont_mask = 1; if (flags & FUSE_AUTO_INVAL_DATA) fc->auto_inval_data = 1; else if (flags & FUSE_EXPLICIT_INVAL_DATA) fc->explicit_inval_data = 1; if (flags & FUSE_DO_READDIRPLUS) { fc->do_readdirplus = 1; if (flags & FUSE_READDIRPLUS_AUTO) fc->readdirplus_auto = 1; } if (flags & FUSE_ASYNC_DIO) fc->async_dio = 1; if (flags & FUSE_WRITEBACK_CACHE) fc->writeback_cache = 1; if (flags & FUSE_PARALLEL_DIROPS) fc->parallel_dirops = 1; if (flags & FUSE_HANDLE_KILLPRIV) fc->handle_killpriv = 1; if (arg->time_gran && arg->time_gran <= 1000000000) fm->sb->s_time_gran = arg->time_gran; if ((flags & FUSE_POSIX_ACL)) { fc->default_permissions = 1; fc->posix_acl = 1; fm->sb->s_xattr = fuse_acl_xattr_handlers; } if (flags & FUSE_CACHE_SYMLINKS) fc->cache_symlinks = 1; if (flags & FUSE_ABORT_ERROR) fc->abort_err = 1; if (flags & FUSE_MAX_PAGES) { fc->max_pages = min_t(unsigned int, fc->max_pages_limit, max_t(unsigned int, arg->max_pages, 1)); } if (IS_ENABLED(CONFIG_FUSE_DAX)) { if (flags & FUSE_MAP_ALIGNMENT && !fuse_dax_check_alignment(fc, arg->map_alignment)) { ok = false; } if (flags & FUSE_HAS_INODE_DAX) fc->inode_dax = 1; } if (flags & FUSE_HANDLE_KILLPRIV_V2) { fc->handle_killpriv_v2 = 1; fm->sb->s_flags |= SB_NOSEC; } if (flags & FUSE_SETXATTR_EXT) fc->setxattr_ext = 1; if (flags & FUSE_SECURITY_CTX) fc->init_security = 1; } else { ra_pages = fc->max_read / PAGE_SIZE; fc->no_lock = 1; fc->no_flock = 1; } fm->sb->s_bdi->ra_pages = min(fm->sb->s_bdi->ra_pages, ra_pages); fc->minor = arg->minor; fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; fc->max_write = max_t(unsigned, 4096, fc->max_write); fc->conn_init = 1; } kfree(ia); if (!ok) { fc->conn_init = 0; fc->conn_error = 1; } fuse_set_initialized(fc); wake_up_all(&fc->blocked_waitq); } void fuse_send_init(struct fuse_mount *fm) { struct fuse_init_args *ia; u64 flags; ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL); ia->in.major = FUSE_KERNEL_VERSION; ia->in.minor = FUSE_KERNEL_MINOR_VERSION; ia->in.max_readahead = fm->sb->s_bdi->ra_pages * PAGE_SIZE; flags = FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC | FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK | FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ | FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA | FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO | FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT | FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL | FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS | FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA | FUSE_HANDLE_KILLPRIV_V2 | FUSE_SETXATTR_EXT | FUSE_INIT_EXT | FUSE_SECURITY_CTX; #ifdef CONFIG_FUSE_DAX if (fm->fc->dax) flags |= FUSE_MAP_ALIGNMENT; if (fuse_is_inode_dax_mode(fm->fc->dax_mode)) flags |= FUSE_HAS_INODE_DAX; #endif if (fm->fc->auto_submounts) flags |= FUSE_SUBMOUNTS; ia->in.flags = flags; ia->in.flags2 = flags >> 32; ia->args.opcode = FUSE_INIT; ia->args.in_numargs = 1; ia->args.in_args[0].size = sizeof(ia->in); ia->args.in_args[0].value = &ia->in; ia->args.out_numargs = 1; /* Variable length argument used for backward compatibility with interface version < 7.5. Rest of init_out is zeroed by do_get_request(), so a short reply is not a problem */ ia->args.out_argvar = true; ia->args.out_args[0].size = sizeof(ia->out); ia->args.out_args[0].value = &ia->out; ia->args.force = true; ia->args.nocreds = true; ia->args.end = process_init_reply; if (fuse_simple_background(fm, &ia->args, GFP_KERNEL) != 0) process_init_reply(fm, &ia->args, -ENOTCONN); } EXPORT_SYMBOL_GPL(fuse_send_init); void fuse_free_conn(struct fuse_conn *fc) { WARN_ON(!list_empty(&fc->devices)); kfree_rcu(fc, rcu); } EXPORT_SYMBOL_GPL(fuse_free_conn); static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb) { int err; char *suffix = ""; if (sb->s_bdev) { suffix = "-fuseblk"; /* * sb->s_bdi points to blkdev's bdi however we want to redirect * it to our private bdi... */ bdi_put(sb->s_bdi); sb->s_bdi = &noop_backing_dev_info; } err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev), MINOR(fc->dev), suffix); if (err) return err; /* fuse does it's own writeback accounting */ sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT; sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT; /* * For a single fuse filesystem use max 1% of dirty + * writeback threshold. * * This gives about 1M of write buffer for memory maps on a * machine with 1G and 10% dirty_ratio, which should be more * than enough. * * Privileged users can raise it by writing to * * /sys/class/bdi//max_ratio */ bdi_set_max_ratio(sb->s_bdi, 1); return 0; } struct fuse_dev *fuse_dev_alloc(void) { struct fuse_dev *fud; struct list_head *pq; fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL); if (!fud) return NULL; pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL); if (!pq) { kfree(fud); return NULL; } fud->pq.processing = pq; fuse_pqueue_init(&fud->pq); return fud; } EXPORT_SYMBOL_GPL(fuse_dev_alloc); void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc) { fud->fc = fuse_conn_get(fc); spin_lock(&fc->lock); list_add_tail(&fud->entry, &fc->devices); spin_unlock(&fc->lock); } EXPORT_SYMBOL_GPL(fuse_dev_install); struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc) { struct fuse_dev *fud; fud = fuse_dev_alloc(); if (!fud) return NULL; fuse_dev_install(fud, fc); return fud; } EXPORT_SYMBOL_GPL(fuse_dev_alloc_install); void fuse_dev_free(struct fuse_dev *fud) { struct fuse_conn *fc = fud->fc; if (fc) { spin_lock(&fc->lock); list_del(&fud->entry); spin_unlock(&fc->lock); fuse_conn_put(fc); } kfree(fud->pq.processing); kfree(fud); } EXPORT_SYMBOL_GPL(fuse_dev_free); static void fuse_fill_attr_from_inode(struct fuse_attr *attr, const struct fuse_inode *fi) { *attr = (struct fuse_attr){ .ino = fi->inode.i_ino, .size = fi->inode.i_size, .blocks = fi->inode.i_blocks, .atime = fi->inode.i_atime.tv_sec, .mtime = fi->inode.i_mtime.tv_sec, .ctime = fi->inode.i_ctime.tv_sec, .atimensec = fi->inode.i_atime.tv_nsec, .mtimensec = fi->inode.i_mtime.tv_nsec, .ctimensec = fi->inode.i_ctime.tv_nsec, .mode = fi->inode.i_mode, .nlink = fi->inode.i_nlink, .uid = fi->inode.i_uid.val, .gid = fi->inode.i_gid.val, .rdev = fi->inode.i_rdev, .blksize = 1u << fi->inode.i_blkbits, }; } static void fuse_sb_defaults(struct super_block *sb) { sb->s_magic = FUSE_SUPER_MAGIC; sb->s_op = &fuse_super_operations; sb->s_xattr = fuse_xattr_handlers; sb->s_maxbytes = MAX_LFS_FILESIZE; sb->s_time_gran = 1; sb->s_export_op = &fuse_export_operations; sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE; if (sb->s_user_ns != &init_user_ns) sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER; sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION); /* * If we are not in the initial user namespace posix * acls must be translated. */ if (sb->s_user_ns != &init_user_ns) sb->s_xattr = fuse_no_acl_xattr_handlers; } static int fuse_fill_super_submount(struct super_block *sb, struct fuse_inode *parent_fi) { struct fuse_mount *fm = get_fuse_mount_super(sb); struct super_block *parent_sb = parent_fi->inode.i_sb; struct fuse_attr root_attr; struct inode *root; fuse_sb_defaults(sb); fm->sb = sb; WARN_ON(sb->s_bdi != &noop_backing_dev_info); sb->s_bdi = bdi_get(parent_sb->s_bdi); sb->s_xattr = parent_sb->s_xattr; sb->s_time_gran = parent_sb->s_time_gran; sb->s_blocksize = parent_sb->s_blocksize; sb->s_blocksize_bits = parent_sb->s_blocksize_bits; sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL); if (parent_sb->s_subtype && !sb->s_subtype) return -ENOMEM; fuse_fill_attr_from_inode(&root_attr, parent_fi); root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0); /* * This inode is just a duplicate, so it is not looked up and * its nlookup should not be incremented. fuse_iget() does * that, though, so undo it here. */ get_fuse_inode(root)->nlookup--; sb->s_d_op = &fuse_dentry_operations; sb->s_root = d_make_root(root); if (!sb->s_root) return -ENOMEM; return 0; } /* Filesystem context private data holds the FUSE inode of the mount point */ static int fuse_get_tree_submount(struct fs_context *fsc) { struct fuse_mount *fm; struct fuse_inode *mp_fi = fsc->fs_private; struct fuse_conn *fc = get_fuse_conn(&mp_fi->inode); struct super_block *sb; int err; fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL); if (!fm) return -ENOMEM; fm->fc = fuse_conn_get(fc); fsc->s_fs_info = fm; sb = sget_fc(fsc, NULL, set_anon_super_fc); if (fsc->s_fs_info) fuse_mount_destroy(fm); if (IS_ERR(sb)) return PTR_ERR(sb); /* Initialize superblock, making @mp_fi its root */ err = fuse_fill_super_submount(sb, mp_fi); if (err) { deactivate_locked_super(sb); return err; } down_write(&fc->killsb); list_add_tail(&fm->fc_entry, &fc->mounts); up_write(&fc->killsb); sb->s_flags |= SB_ACTIVE; fsc->root = dget(sb->s_root); return 0; } static const struct fs_context_operations fuse_context_submount_ops = { .get_tree = fuse_get_tree_submount, }; int fuse_init_fs_context_submount(struct fs_context *fsc) { fsc->ops = &fuse_context_submount_ops; return 0; } EXPORT_SYMBOL_GPL(fuse_init_fs_context_submount); int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx) { struct fuse_dev *fud = NULL; struct fuse_mount *fm = get_fuse_mount_super(sb); struct fuse_conn *fc = fm->fc; struct inode *root; struct dentry *root_dentry; int err; err = -EINVAL; if (sb->s_flags & SB_MANDLOCK) goto err; rcu_assign_pointer(fc->curr_bucket, fuse_sync_bucket_alloc()); fuse_sb_defaults(sb); if (ctx->is_bdev) { #ifdef CONFIG_BLOCK err = -EINVAL; if (!sb_set_blocksize(sb, ctx->blksize)) goto err; #endif } else { sb->s_blocksize = PAGE_SIZE; sb->s_blocksize_bits = PAGE_SHIFT; } sb->s_subtype = ctx->subtype; ctx->subtype = NULL; if (IS_ENABLED(CONFIG_FUSE_DAX)) { err = fuse_dax_conn_alloc(fc, ctx->dax_mode, ctx->dax_dev); if (err) goto err; } if (ctx->fudptr) { err = -ENOMEM; fud = fuse_dev_alloc_install(fc); if (!fud) goto err_free_dax; } fc->dev = sb->s_dev; fm->sb = sb; err = fuse_bdi_init(fc, sb); if (err) goto err_dev_free; /* Handle umasking inside the fuse code */ if (sb->s_flags & SB_POSIXACL) fc->dont_mask = 1; sb->s_flags |= SB_POSIXACL; fc->default_permissions = ctx->default_permissions; fc->allow_other = ctx->allow_other; fc->user_id = ctx->user_id; fc->group_id = ctx->group_id; fc->legacy_opts_show = ctx->legacy_opts_show; fc->max_read = max_t(unsigned int, 4096, ctx->max_read); fc->destroy = ctx->destroy; fc->no_control = ctx->no_control; fc->no_force_umount = ctx->no_force_umount; err = -ENOMEM; root = fuse_get_root_inode(sb, ctx->rootmode); sb->s_d_op = &fuse_root_dentry_operations; root_dentry = d_make_root(root); if (!root_dentry) goto err_dev_free; /* Root dentry doesn't have .d_revalidate */ sb->s_d_op = &fuse_dentry_operations; mutex_lock(&fuse_mutex); err = -EINVAL; if (ctx->fudptr && *ctx->fudptr) goto err_unlock; err = fuse_ctl_add_conn(fc); if (err) goto err_unlock; list_add_tail(&fc->entry, &fuse_conn_list); sb->s_root = root_dentry; if (ctx->fudptr) *ctx->fudptr = fud; mutex_unlock(&fuse_mutex); return 0; err_unlock: mutex_unlock(&fuse_mutex); dput(root_dentry); err_dev_free: if (fud) fuse_dev_free(fud); err_free_dax: if (IS_ENABLED(CONFIG_FUSE_DAX)) fuse_dax_conn_free(fc); err: return err; } EXPORT_SYMBOL_GPL(fuse_fill_super_common); static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc) { struct fuse_fs_context *ctx = fsc->fs_private; int err; if (!ctx->file || !ctx->rootmode_present || !ctx->user_id_present || !ctx->group_id_present) return -EINVAL; /* * Require mount to happen from the same user namespace which * opened /dev/fuse to prevent potential attacks. */ if ((ctx->file->f_op != &fuse_dev_operations) || (ctx->file->f_cred->user_ns != sb->s_user_ns)) return -EINVAL; ctx->fudptr = &ctx->file->private_data; err = fuse_fill_super_common(sb, ctx); if (err) return err; /* file->private_data shall be visible on all CPUs after this */ smp_mb(); fuse_send_init(get_fuse_mount_super(sb)); return 0; } /* * This is the path where user supplied an already initialized fuse dev. In * this case never create a new super if the old one is gone. */ static int fuse_set_no_super(struct super_block *sb, struct fs_context *fsc) { return -ENOTCONN; } static int fuse_test_super(struct super_block *sb, struct fs_context *fsc) { return fsc->sget_key == get_fuse_conn_super(sb); } static int fuse_get_tree(struct fs_context *fsc) { struct fuse_fs_context *ctx = fsc->fs_private; struct fuse_dev *fud; struct fuse_conn *fc; struct fuse_mount *fm; struct super_block *sb; int err; fc = kmalloc(sizeof(*fc), GFP_KERNEL); if (!fc) return -ENOMEM; fm = kzalloc(sizeof(*fm), GFP_KERNEL); if (!fm) { kfree(fc); return -ENOMEM; } fuse_conn_init(fc, fm, fsc->user_ns, &fuse_dev_fiq_ops, NULL); fc->release = fuse_free_conn; fsc->s_fs_info = fm; if (ctx->fd_present) ctx->file = fget(ctx->fd); if (IS_ENABLED(CONFIG_BLOCK) && ctx->is_bdev) { err = get_tree_bdev(fsc, fuse_fill_super); goto out; } /* * While block dev mount can be initialized with a dummy device fd * (found by device name), normal fuse mounts can't */ err = -EINVAL; if (!ctx->file) goto out; /* * Allow creating a fuse mount with an already initialized fuse * connection */ fud = READ_ONCE(ctx->file->private_data); if (ctx->file->f_op == &fuse_dev_operations && fud) { fsc->sget_key = fud->fc; sb = sget_fc(fsc, fuse_test_super, fuse_set_no_super); err = PTR_ERR_OR_ZERO(sb); if (!IS_ERR(sb)) fsc->root = dget(sb->s_root); } else { err = get_tree_nodev(fsc, fuse_fill_super); } out: if (fsc->s_fs_info) fuse_mount_destroy(fm); if (ctx->file) fput(ctx->file); return err; } static const struct fs_context_operations fuse_context_ops = { .free = fuse_free_fsc, .parse_param = fuse_parse_param, .reconfigure = fuse_reconfigure, .get_tree = fuse_get_tree, }; /* * Set up the filesystem mount context. */ static int fuse_init_fs_context(struct fs_context *fsc) { struct fuse_fs_context *ctx; ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL); if (!ctx) return -ENOMEM; ctx->max_read = ~0; ctx->blksize = FUSE_DEFAULT_BLKSIZE; ctx->legacy_opts_show = true; #ifdef CONFIG_BLOCK if (fsc->fs_type == &fuseblk_fs_type) { ctx->is_bdev = true; ctx->destroy = true; } #endif fsc->fs_private = ctx; fsc->ops = &fuse_context_ops; return 0; } bool fuse_mount_remove(struct fuse_mount *fm) { struct fuse_conn *fc = fm->fc; bool last = false; down_write(&fc->killsb); list_del_init(&fm->fc_entry); if (list_empty(&fc->mounts)) last = true; up_write(&fc->killsb); return last; } EXPORT_SYMBOL_GPL(fuse_mount_remove); void fuse_conn_destroy(struct fuse_mount *fm) { struct fuse_conn *fc = fm->fc; if (fc->destroy) fuse_send_destroy(fm); fuse_abort_conn(fc); fuse_wait_aborted(fc); if (!list_empty(&fc->entry)) { mutex_lock(&fuse_mutex); list_del(&fc->entry); fuse_ctl_remove_conn(fc); mutex_unlock(&fuse_mutex); } } EXPORT_SYMBOL_GPL(fuse_conn_destroy); static void fuse_sb_destroy(struct super_block *sb) { struct fuse_mount *fm = get_fuse_mount_super(sb); bool last; if (sb->s_root) { last = fuse_mount_remove(fm); if (last) fuse_conn_destroy(fm); } } void fuse_mount_destroy(struct fuse_mount *fm) { fuse_conn_put(fm->fc); kfree(fm); } EXPORT_SYMBOL(fuse_mount_destroy); static void fuse_kill_sb_anon(struct super_block *sb) { fuse_sb_destroy(sb); kill_anon_super(sb); fuse_mount_destroy(get_fuse_mount_super(sb)); } static struct file_system_type fuse_fs_type = { .owner = THIS_MODULE, .name = "fuse", .fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT, .init_fs_context = fuse_init_fs_context, .parameters = fuse_fs_parameters, .kill_sb = fuse_kill_sb_anon, }; MODULE_ALIAS_FS("fuse"); #ifdef CONFIG_BLOCK static void fuse_kill_sb_blk(struct super_block *sb) { fuse_sb_destroy(sb); kill_block_super(sb); fuse_mount_destroy(get_fuse_mount_super(sb)); } static struct file_system_type fuseblk_fs_type = { .owner = THIS_MODULE, .name = "fuseblk", .init_fs_context = fuse_init_fs_context, .parameters = fuse_fs_parameters, .kill_sb = fuse_kill_sb_blk, .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, }; MODULE_ALIAS_FS("fuseblk"); static inline int register_fuseblk(void) { return register_filesystem(&fuseblk_fs_type); } static inline void unregister_fuseblk(void) { unregister_filesystem(&fuseblk_fs_type); } #else static inline int register_fuseblk(void) { return 0; } static inline void unregister_fuseblk(void) { } #endif static void fuse_inode_init_once(void *foo) { struct inode *inode = foo; inode_init_once(inode); } static int __init fuse_fs_init(void) { int err; fuse_inode_cachep = kmem_cache_create("fuse_inode", sizeof(struct fuse_inode), 0, SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT, fuse_inode_init_once); err = -ENOMEM; if (!fuse_inode_cachep) goto out; err = register_fuseblk(); if (err) goto out2; err = register_filesystem(&fuse_fs_type); if (err) goto out3; return 0; out3: unregister_fuseblk(); out2: kmem_cache_destroy(fuse_inode_cachep); out: return err; } static void fuse_fs_cleanup(void) { unregister_filesystem(&fuse_fs_type); unregister_fuseblk(); /* * Make sure all delayed rcu free inodes are flushed before we * destroy cache. */ rcu_barrier(); kmem_cache_destroy(fuse_inode_cachep); } static struct kobject *fuse_kobj; static int fuse_sysfs_init(void) { int err; fuse_kobj = kobject_create_and_add("fuse", fs_kobj); if (!fuse_kobj) { err = -ENOMEM; goto out_err; } err = sysfs_create_mount_point(fuse_kobj, "connections"); if (err) goto out_fuse_unregister; return 0; out_fuse_unregister: kobject_put(fuse_kobj); out_err: return err; } static void fuse_sysfs_cleanup(void) { sysfs_remove_mount_point(fuse_kobj, "connections"); kobject_put(fuse_kobj); } static int __init fuse_init(void) { int res; pr_info("init (API version %i.%i)\n", FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); INIT_LIST_HEAD(&fuse_conn_list); res = fuse_fs_init(); if (res) goto err; res = fuse_dev_init(); if (res) goto err_fs_cleanup; res = fuse_sysfs_init(); if (res) goto err_dev_cleanup; res = fuse_ctl_init(); if (res) goto err_sysfs_cleanup; sanitize_global_limit(&max_user_bgreq); sanitize_global_limit(&max_user_congthresh); return 0; err_sysfs_cleanup: fuse_sysfs_cleanup(); err_dev_cleanup: fuse_dev_cleanup(); err_fs_cleanup: fuse_fs_cleanup(); err: return res; } static void __exit fuse_exit(void) { pr_debug("exit\n"); fuse_ctl_cleanup(); fuse_sysfs_cleanup(); fuse_fs_cleanup(); fuse_dev_cleanup(); } module_init(fuse_init); module_exit(fuse_exit);