diff options
Diffstat (limited to 'fs/fuse/inode.c')
| -rw-r--r-- | fs/fuse/inode.c | 2068 |
1 files changed, 2068 insertions, 0 deletions
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c new file mode 100644 index 000000000..f81000d96 --- /dev/null +++ b/fs/fuse/inode.c @@ -0,0 +1,2068 @@ +/* + FUSE: Filesystem in Userspace + Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> + + This program can be distributed under the terms of the GNU GPL. + See the file COPYING. +*/ + +#include "fuse_i.h" + +#include <linux/pagemap.h> +#include <linux/slab.h> +#include <linux/file.h> +#include <linux/seq_file.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/fs_context.h> +#include <linux/fs_parser.h> +#include <linux/statfs.h> +#include <linux/random.h> +#include <linux/sched.h> +#include <linux/exportfs.h> +#include <linux/posix_acl.h> +#include <linux/pid_namespace.h> +#include <uapi/linux/magic.h> + +MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); +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 fuse_submount_lookup *fuse_alloc_submount_lookup(void) +{ + struct fuse_submount_lookup *sl; + + sl = kzalloc(sizeof(struct fuse_submount_lookup), GFP_KERNEL_ACCOUNT); + if (!sl) + return NULL; + sl->forget = fuse_alloc_forget(); + if (!sl->forget) + goto out_free; + + return sl; + +out_free: + kfree(sl); + return NULL; +} + +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; + fi->submount_lookup = NULL; + 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_cleanup_submount_lookup(struct fuse_conn *fc, + struct fuse_submount_lookup *sl) +{ + if (!refcount_dec_and_test(&sl->count)) + return; + + fuse_queue_forget(fc, sl->forget, sl->nodeid, 1); + sl->forget = NULL; + kfree(sl); +} + +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 (fi->submount_lookup) { + fuse_cleanup_submount_lookup(fc, fi->submount_lookup); + fi->submount_lookup = 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_submount_lookup(struct fuse_submount_lookup *sl, + u64 nodeid) +{ + sl->nodeid = nodeid; + refcount_set(&sl->count, 1); +} + +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)) { + struct fuse_inode *fi; + + inode = new_inode(sb); + if (!inode) + return NULL; + + fuse_init_inode(inode, attr); + fi = get_fuse_inode(inode); + fi->nodeid = nodeid; + fi->submount_lookup = fuse_alloc_submount_lookup(); + if (!fi->submount_lookup) { + iput(inode); + return NULL; + } + /* Sets nlookup = 1 on fi->submount_lookup->nlookup */ + fuse_init_submount_lookup(fi->submount_lookup, 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; + } + fi = get_fuse_inode(inode); + spin_lock(&fi->lock); + fi->nlookup++; + spin_unlock(&fi->lock); +done: + 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/<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; + struct fuse_submount_lookup *sl; + struct fuse_inode *fi; + + 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. + */ + fi = get_fuse_inode(root); + fi->nlookup--; + + sb->s_d_op = &fuse_dentry_operations; + sb->s_root = d_make_root(root); + if (!sb->s_root) + return -ENOMEM; + + /* + * Grab the parent's submount_lookup pointer and take a + * reference on the shared nlookup from the parent. This is to + * prevent the last forget for this nodeid from getting + * triggered until all users have finished with it. + */ + sl = parent_fi->submount_lookup; + WARN_ON(!sl); + if (sl) { + refcount_inc(&sl->count); + fi->submount_lookup = sl; + } + + 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); |