diff options
Diffstat (limited to '')
| -rw-r--r-- | fs/fuse/inode.c | 1421 |
1 files changed, 1421 insertions, 0 deletions
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c new file mode 100644 index 000000000..821597c61 --- /dev/null +++ b/fs/fuse/inode.c @@ -0,0 +1,1421 @@ +/* + 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/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> + +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_SUPER_MAGIC 0x65735546 + +#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) + +struct fuse_mount_data { + int fd; + unsigned rootmode; + kuid_t user_id; + kgid_t group_id; + unsigned fd_present:1; + unsigned rootmode_present:1; + unsigned user_id_present:1; + unsigned group_id_present:1; + unsigned default_permissions:1; + unsigned allow_other:1; + unsigned max_read; + unsigned blksize; +}; + +struct fuse_forget_link *fuse_alloc_forget(void) +{ + return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL); +} + +static struct inode *fuse_alloc_inode(struct super_block *sb) +{ + struct inode *inode; + struct fuse_inode *fi; + + inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL); + if (!inode) + return NULL; + + fi = get_fuse_inode(inode); + fi->i_time = 0; + fi->nodeid = 0; + fi->nlookup = 0; + fi->attr_version = 0; + fi->writectr = 0; + fi->orig_ino = 0; + fi->state = 0; + INIT_LIST_HEAD(&fi->write_files); + INIT_LIST_HEAD(&fi->queued_writes); + INIT_LIST_HEAD(&fi->writepages); + init_waitqueue_head(&fi->page_waitq); + mutex_init(&fi->mutex); + fi->forget = fuse_alloc_forget(); + if (!fi->forget) { + kmem_cache_free(fuse_inode_cachep, inode); + return NULL; + } + + return inode; +} + +static void fuse_i_callback(struct rcu_head *head) +{ + struct inode *inode = container_of(head, struct inode, i_rcu); + kmem_cache_free(fuse_inode_cachep, inode); +} + +static void fuse_destroy_inode(struct inode *inode) +{ + struct fuse_inode *fi = get_fuse_inode(inode); + BUG_ON(!list_empty(&fi->write_files)); + BUG_ON(!list_empty(&fi->queued_writes)); + mutex_destroy(&fi->mutex); + kfree(fi->forget); + call_rcu(&inode->i_rcu, fuse_i_callback); +} + +static void fuse_evict_inode(struct inode *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); + struct fuse_inode *fi = get_fuse_inode(inode); + fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup); + fi->forget = NULL; + } +} + +static int fuse_remount_fs(struct super_block *sb, int *flags, char *data) +{ + sync_filesystem(sb); + if (*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) +{ + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_inode *fi = get_fuse_inode(inode); + + fi->attr_version = ++fc->attr_version; + fi->i_time = attr_valid; + + 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; + 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 (!fc->writeback_cache || !S_ISREG(inode->i_mode)) { + 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 (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; +} + +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); + bool is_wb = fc->writeback_cache; + loff_t oldsize; + struct timespec64 old_mtime; + + spin_lock(&fc->lock); + if ((attr_version != 0 && fi->attr_version > attr_version) || + test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) { + spin_unlock(&fc->lock); + return; + } + + old_mtime = inode->i_mtime; + fuse_change_attributes_common(inode, attr, attr_valid); + + 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 (!is_wb || !S_ISREG(inode->i_mode)) + i_size_write(inode, attr->size); + spin_unlock(&fc->lock); + + if (!is_wb && S_ISREG(inode->i_mode)) { + bool inval = false; + + if (oldsize != attr->size) { + truncate_pagecache(inode, attr->size); + 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); + } +} + +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); + } 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(); +} + +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); + + 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 ((inode->i_mode ^ attr->mode) & S_IFMT) { + /* Inode has changed type, any I/O on the old should fail */ + fuse_make_bad(inode); + iput(inode); + goto retry; + } + + fi = get_fuse_inode(inode); + spin_lock(&fc->lock); + fi->nlookup++; + spin_unlock(&fc->lock); + fuse_change_attributes(inode, attr, attr_valid, attr_version); + + return inode; +} + +int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid, + loff_t offset, loff_t len) +{ + struct inode *inode; + pgoff_t pg_start; + pgoff_t pg_end; + + inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid); + if (!inode) + return -ENOENT; + + 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) +{ + fuse_abort_conn(get_fuse_conn_super(sb), false); +} + +static void fuse_send_destroy(struct fuse_conn *fc) +{ + struct fuse_req *req = fc->destroy_req; + if (req && fc->conn_init) { + fc->destroy_req = NULL; + req->in.h.opcode = FUSE_DESTROY; + __set_bit(FR_FORCE, &req->flags); + __clear_bit(FR_BACKGROUND, &req->flags); + fuse_request_send(fc, req); + fuse_put_request(fc, req); + } +} + +static void fuse_put_super(struct super_block *sb) +{ + struct fuse_conn *fc = get_fuse_conn_super(sb); + + mutex_lock(&fuse_mutex); + list_del(&fc->entry); + fuse_ctl_remove_conn(fc); + mutex_unlock(&fuse_mutex); + + fuse_conn_put(fc); +} + +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_conn *fc = get_fuse_conn_super(sb); + FUSE_ARGS(args); + struct fuse_statfs_out outarg; + int err; + + if (!fuse_allow_current_process(fc)) { + buf->f_type = FUSE_SUPER_MAGIC; + return 0; + } + + memset(&outarg, 0, sizeof(outarg)); + args.in.numargs = 0; + args.in.h.opcode = FUSE_STATFS; + args.in.h.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(fc, &args); + if (!err) + convert_fuse_statfs(buf, &outarg.st); + return err; +} + +enum { + 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 match_table_t tokens = { + {OPT_FD, "fd=%u"}, + {OPT_ROOTMODE, "rootmode=%o"}, + {OPT_USER_ID, "user_id=%u"}, + {OPT_GROUP_ID, "group_id=%u"}, + {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, + {OPT_ALLOW_OTHER, "allow_other"}, + {OPT_MAX_READ, "max_read=%u"}, + {OPT_BLKSIZE, "blksize=%u"}, + {OPT_ERR, NULL} +}; + +static int fuse_match_uint(substring_t *s, unsigned int *res) +{ + int err = -ENOMEM; + char *buf = match_strdup(s); + if (buf) { + err = kstrtouint(buf, 10, res); + kfree(buf); + } + return err; +} + +static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev, + struct user_namespace *user_ns) +{ + char *p; + memset(d, 0, sizeof(struct fuse_mount_data)); + d->max_read = ~0; + d->blksize = FUSE_DEFAULT_BLKSIZE; + + while ((p = strsep(&opt, ",")) != NULL) { + int token; + int value; + unsigned uv; + substring_t args[MAX_OPT_ARGS]; + if (!*p) + continue; + + token = match_token(p, tokens, args); + switch (token) { + case OPT_FD: + if (match_int(&args[0], &value)) + return 0; + d->fd = value; + d->fd_present = 1; + break; + + case OPT_ROOTMODE: + if (match_octal(&args[0], &value)) + return 0; + if (!fuse_valid_type(value)) + return 0; + d->rootmode = value; + d->rootmode_present = 1; + break; + + case OPT_USER_ID: + if (fuse_match_uint(&args[0], &uv)) + return 0; + d->user_id = make_kuid(user_ns, uv); + if (!uid_valid(d->user_id)) + return 0; + d->user_id_present = 1; + break; + + case OPT_GROUP_ID: + if (fuse_match_uint(&args[0], &uv)) + return 0; + d->group_id = make_kgid(user_ns, uv); + if (!gid_valid(d->group_id)) + return 0; + d->group_id_present = 1; + break; + + case OPT_DEFAULT_PERMISSIONS: + d->default_permissions = 1; + break; + + case OPT_ALLOW_OTHER: + d->allow_other = 1; + break; + + case OPT_MAX_READ: + if (match_int(&args[0], &value)) + return 0; + d->max_read = value; + break; + + case OPT_BLKSIZE: + if (!is_bdev || match_int(&args[0], &value)) + return 0; + d->blksize = value; + break; + + default: + return 0; + } + } + + if (!d->fd_present || !d->rootmode_present || + !d->user_id_present || !d->group_id_present) + return 0; + + return 1; +} + +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); + + 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); + return 0; +} + +static void fuse_iqueue_init(struct fuse_iqueue *fiq) +{ + 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; +} + +static void fuse_pqueue_init(struct fuse_pqueue *fpq) +{ + memset(fpq, 0, sizeof(struct fuse_pqueue)); + spin_lock_init(&fpq->lock); + INIT_LIST_HEAD(&fpq->processing); + INIT_LIST_HEAD(&fpq->io); + fpq->connected = 1; +} + +void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns) +{ + memset(fc, 0, sizeof(*fc)); + spin_lock_init(&fc->lock); + init_rwsem(&fc->killsb); + refcount_set(&fc->count, 1); + atomic_set(&fc->dev_count, 1); + init_waitqueue_head(&fc->blocked_waitq); + init_waitqueue_head(&fc->reserved_req_waitq); + fuse_iqueue_init(&fc->iq); + 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; + fc->khctr = 0; + fc->polled_files = RB_ROOT; + fc->blocked = 0; + fc->initialized = 0; + fc->connected = 1; + 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); +} +EXPORT_SYMBOL_GPL(fuse_conn_init); + +void fuse_conn_put(struct fuse_conn *fc) +{ + if (refcount_dec_and_test(&fc->count)) { + if (fc->destroy_req) + fuse_request_free(fc->destroy_req); + put_pid_ns(fc->pid_ns); + put_user_ns(fc->user_ns); + 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; + const struct qstr name = QSTR_INIT("..", 2); + int err; + + if (!fc->export_support) + return ERR_PTR(-ESTALE); + + err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), + &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, + .destroy_inode = fuse_destroy_inode, + .evict_inode = fuse_evict_inode, + .write_inode = fuse_write_inode, + .drop_inode = generic_delete_inode, + .remount_fs = fuse_remount_fs, + .put_super = fuse_put_super, + .umount_begin = fuse_umount_begin, + .statfs = fuse_statfs, + .show_options = fuse_show_options, +}; + +static void sanitize_global_limit(unsigned *limit) +{ + if (*limit == 0) + *limit = ((totalram_pages << PAGE_SHIFT) >> 13) / + sizeof(struct fuse_req); + + 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); + + 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; + } +} + +static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) +{ + struct fuse_init_out *arg = &req->misc.init_out; + + if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION) + fc->conn_error = 1; + else { + unsigned long ra_pages; + + process_init_limits(fc, arg); + + if (arg->minor >= 6) { + ra_pages = arg->max_readahead / PAGE_SIZE; + if (arg->flags & FUSE_ASYNC_READ) + fc->async_read = 1; + if (!(arg->flags & FUSE_POSIX_LOCKS)) + fc->no_lock = 1; + if (arg->minor >= 17) { + if (!(arg->flags & FUSE_FLOCK_LOCKS)) + fc->no_flock = 1; + } else { + if (!(arg->flags & FUSE_POSIX_LOCKS)) + fc->no_flock = 1; + } + if (arg->flags & FUSE_ATOMIC_O_TRUNC) + fc->atomic_o_trunc = 1; + if (arg->minor >= 9) { + /* LOOKUP has dependency on proto version */ + if (arg->flags & FUSE_EXPORT_SUPPORT) + fc->export_support = 1; + } + if (arg->flags & FUSE_BIG_WRITES) + fc->big_writes = 1; + if (arg->flags & FUSE_DONT_MASK) + fc->dont_mask = 1; + if (arg->flags & FUSE_AUTO_INVAL_DATA) + fc->auto_inval_data = 1; + if (arg->flags & FUSE_DO_READDIRPLUS) { + fc->do_readdirplus = 1; + if (arg->flags & FUSE_READDIRPLUS_AUTO) + fc->readdirplus_auto = 1; + } + if (arg->flags & FUSE_ASYNC_DIO) + fc->async_dio = 1; + if (arg->flags & FUSE_WRITEBACK_CACHE) + fc->writeback_cache = 1; + if (arg->flags & FUSE_PARALLEL_DIROPS) + fc->parallel_dirops = 1; + if (arg->flags & FUSE_HANDLE_KILLPRIV) + fc->handle_killpriv = 1; + if (arg->time_gran && arg->time_gran <= 1000000000) + fc->sb->s_time_gran = arg->time_gran; + if ((arg->flags & FUSE_POSIX_ACL)) { + fc->default_permissions = 1; + fc->posix_acl = 1; + fc->sb->s_xattr = fuse_acl_xattr_handlers; + } + if (arg->flags & FUSE_ABORT_ERROR) + fc->abort_err = 1; + } else { + ra_pages = fc->max_read / PAGE_SIZE; + fc->no_lock = 1; + fc->no_flock = 1; + } + + fc->sb->s_bdi->ra_pages = + min(fc->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; + } + fuse_set_initialized(fc); + wake_up_all(&fc->blocked_waitq); +} + +static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) +{ + struct fuse_init_in *arg = &req->misc.init_in; + + arg->major = FUSE_KERNEL_VERSION; + arg->minor = FUSE_KERNEL_MINOR_VERSION; + arg->max_readahead = fc->sb->s_bdi->ra_pages * PAGE_SIZE; + arg->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; + req->in.h.opcode = FUSE_INIT; + req->in.numargs = 1; + req->in.args[0].size = sizeof(*arg); + req->in.args[0].value = arg; + req->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 */ + req->out.argvar = 1; + req->out.args[0].size = sizeof(struct fuse_init_out); + req->out.args[0].value = &req->misc.init_out; + req->end = process_init_reply; + fuse_request_send_background(fc, req); +} + +static void fuse_free_conn(struct fuse_conn *fc) +{ + WARN_ON(!list_empty(&fc->devices)); + kfree_rcu(fc, rcu); +} + +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; + + sb->s_bdi->ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_SIZE; + /* fuse does it's own writeback accounting */ + sb->s_bdi->capabilities = BDI_CAP_NO_ACCT_WB | 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(struct fuse_conn *fc) +{ + struct fuse_dev *fud; + + fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL); + if (fud) { + fud->fc = fuse_conn_get(fc); + fuse_pqueue_init(&fud->pq); + + spin_lock(&fc->lock); + list_add_tail(&fud->entry, &fc->devices); + spin_unlock(&fc->lock); + } + + return fud; +} +EXPORT_SYMBOL_GPL(fuse_dev_alloc); + +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); +} +EXPORT_SYMBOL_GPL(fuse_dev_free); + +static int fuse_fill_super(struct super_block *sb, void *data, int silent) +{ + struct fuse_dev *fud; + struct fuse_conn *fc; + struct inode *root; + struct fuse_mount_data d; + struct file *file; + struct dentry *root_dentry; + struct fuse_req *init_req; + int err; + int is_bdev = sb->s_bdev != NULL; + + err = -EINVAL; + if (sb->s_flags & SB_MANDLOCK) + goto err; + + sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION); + + if (!parse_fuse_opt(data, &d, is_bdev, sb->s_user_ns)) + goto err; + + if (is_bdev) { +#ifdef CONFIG_BLOCK + err = -EINVAL; + if (!sb_set_blocksize(sb, d.blksize)) + goto err; +#endif + } else { + sb->s_blocksize = PAGE_SIZE; + sb->s_blocksize_bits = PAGE_SHIFT; + } + 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; + + file = fget(d.fd); + err = -EINVAL; + if (!file) + goto err; + + /* + * Require mount to happen from the same user namespace which + * opened /dev/fuse to prevent potential attacks. + */ + if (file->f_op != &fuse_dev_operations || + file->f_cred->user_ns != sb->s_user_ns) + goto err_fput; + + /* + * 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; + + fc = kmalloc(sizeof(*fc), GFP_KERNEL); + err = -ENOMEM; + if (!fc) + goto err_fput; + + fuse_conn_init(fc, sb->s_user_ns); + fc->release = fuse_free_conn; + + fud = fuse_dev_alloc(fc); + if (!fud) + goto err_put_conn; + + fc->dev = sb->s_dev; + fc->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 = d.default_permissions; + fc->allow_other = d.allow_other; + fc->user_id = d.user_id; + fc->group_id = d.group_id; + fc->max_read = max_t(unsigned, 4096, d.max_read); + + /* Used by get_root_inode() */ + sb->s_fs_info = fc; + + err = -ENOMEM; + root = fuse_get_root_inode(sb, d.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; + + init_req = fuse_request_alloc(0); + if (!init_req) + goto err_put_root; + __set_bit(FR_BACKGROUND, &init_req->flags); + + if (is_bdev) { + fc->destroy_req = fuse_request_alloc(0); + if (!fc->destroy_req) + goto err_free_init_req; + } + + mutex_lock(&fuse_mutex); + err = -EINVAL; + if (file->private_data) + 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; + file->private_data = fud; + mutex_unlock(&fuse_mutex); + /* + * atomic_dec_and_test() in fput() provides the necessary + * memory barrier for file->private_data to be visible on all + * CPUs after this + */ + fput(file); + + fuse_send_init(fc, init_req); + + return 0; + + err_unlock: + mutex_unlock(&fuse_mutex); + err_free_init_req: + fuse_request_free(init_req); + err_put_root: + dput(root_dentry); + err_dev_free: + fuse_dev_free(fud); + err_put_conn: + fuse_conn_put(fc); + sb->s_fs_info = NULL; + err_fput: + fput(file); + err: + return err; +} + +static struct dentry *fuse_mount(struct file_system_type *fs_type, + int flags, const char *dev_name, + void *raw_data) +{ + return mount_nodev(fs_type, flags, raw_data, fuse_fill_super); +} + +static void fuse_sb_destroy(struct super_block *sb) +{ + struct fuse_conn *fc = get_fuse_conn_super(sb); + + if (fc) { + fuse_send_destroy(fc); + + fuse_abort_conn(fc, false); + fuse_wait_aborted(fc); + + down_write(&fc->killsb); + fc->sb = NULL; + up_write(&fc->killsb); + } +} + +static void fuse_kill_sb_anon(struct super_block *sb) +{ + fuse_sb_destroy(sb); + kill_anon_super(sb); +} + +static struct file_system_type fuse_fs_type = { + .owner = THIS_MODULE, + .name = "fuse", + .fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT, + .mount = fuse_mount, + .kill_sb = fuse_kill_sb_anon, +}; +MODULE_ALIAS_FS("fuse"); + +#ifdef CONFIG_BLOCK +static struct dentry *fuse_mount_blk(struct file_system_type *fs_type, + int flags, const char *dev_name, + void *raw_data) +{ + return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super); +} + +static void fuse_kill_sb_blk(struct super_block *sb) +{ + fuse_sb_destroy(sb); + kill_block_super(sb); +} + +static struct file_system_type fuseblk_fs_type = { + .owner = THIS_MODULE, + .name = "fuseblk", + .mount = fuse_mount_blk, + .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; + + printk(KERN_INFO "fuse 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) +{ + printk(KERN_DEBUG "fuse exit\n"); + + fuse_ctl_cleanup(); + fuse_sysfs_cleanup(); + fuse_fs_cleanup(); + fuse_dev_cleanup(); +} + +module_init(fuse_init); +module_exit(fuse_exit); |