/* FUSE: Filesystem in Userspace Copyright (C) 2001-2006 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/kernel.h> static const struct file_operations fuse_direct_io_file_operations; static int fuse_send_open(struct inode *inode, struct file *file, int isdir, struct fuse_open_out *outargp) { struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_open_in inarg; struct fuse_req *req; int err; req = fuse_get_req(fc); if (IS_ERR(req)) return PTR_ERR(req); memset(&inarg, 0, sizeof(inarg)); inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC); req->in.h.opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN; req->in.h.nodeid = get_node_id(inode); req->in.numargs = 1; req->in.args[0].size = sizeof(inarg); req->in.args[0].value = &inarg; req->out.numargs = 1; req->out.args[0].size = sizeof(*outargp); req->out.args[0].value = outargp; request_send(fc, req); err = req->out.h.error; fuse_put_request(fc, req); return err; } struct fuse_file *fuse_file_alloc(void) { struct fuse_file *ff; ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL); if (ff) { ff->reserved_req = fuse_request_alloc(); if (!ff->reserved_req) { kfree(ff); ff = NULL; } } return ff; } void fuse_file_free(struct fuse_file *ff) { fuse_request_free(ff->reserved_req); kfree(ff); } void fuse_finish_open(struct inode *inode, struct file *file, struct fuse_file *ff, struct fuse_open_out *outarg) { if (outarg->open_flags & FOPEN_DIRECT_IO) file->f_op = &fuse_direct_io_file_operations; if (!(outarg->open_flags & FOPEN_KEEP_CACHE)) invalidate_inode_pages(inode->i_mapping); ff->fh = outarg->fh; file->private_data = ff; } int fuse_open_common(struct inode *inode, struct file *file, int isdir) { struct fuse_open_out outarg; struct fuse_file *ff; int err; /* VFS checks this, but only _after_ ->open() */ if (file->f_flags & O_DIRECT) return -EINVAL; err = generic_file_open(inode, file); if (err) return err; /* If opening the root node, no lookup has been performed on it, so the attributes must be refreshed */ if (get_node_id(inode) == FUSE_ROOT_ID) { err = fuse_do_getattr(inode); if (err) return err; } ff = fuse_file_alloc(); if (!ff) return -ENOMEM; err = fuse_send_open(inode, file, isdir, &outarg); if (err) fuse_file_free(ff); else { if (isdir) outarg.open_flags &= ~FOPEN_DIRECT_IO; fuse_finish_open(inode, file, ff, &outarg); } return err; } struct fuse_req *fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags, int opcode) { struct fuse_req *req = ff->reserved_req; struct fuse_release_in *inarg = &req->misc.release_in; inarg->fh = ff->fh; inarg->flags = flags; req->in.h.opcode = opcode; req->in.h.nodeid = nodeid; req->in.numargs = 1; req->in.args[0].size = sizeof(struct fuse_release_in); req->in.args[0].value = inarg; kfree(ff); return req; } int fuse_release_common(struct inode *inode, struct file *file, int isdir) { struct fuse_file *ff = file->private_data; if (ff) { struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_req *req; req = fuse_release_fill(ff, get_node_id(inode), file->f_flags, isdir ? FUSE_RELEASEDIR : FUSE_RELEASE); /* Hold vfsmount and dentry until release is finished */ req->vfsmount = mntget(file->f_vfsmnt); req->dentry = dget(file->f_dentry); request_send_background(fc, req); } /* Return value is ignored by VFS */ return 0; } static int fuse_open(struct inode *inode, struct file *file) { return fuse_open_common(inode, file, 0); } static int fuse_release(struct inode *inode, struct file *file) { return fuse_release_common(inode, file, 0); } /* * Scramble the ID space with XTEA, so that the value of the files_struct * pointer is not exposed to userspace. */ static u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id) { u32 *k = fc->scramble_key; u64 v = (unsigned long) id; u32 v0 = v; u32 v1 = v >> 32; u32 sum = 0; int i; for (i = 0; i < 32; i++) { v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]); sum += 0x9E3779B9; v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]); } return (u64) v0 + ((u64) v1 << 32); } static int fuse_flush(struct file *file, fl_owner_t id) { struct inode *inode = file->f_dentry->d_inode; struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_file *ff = file->private_data; struct fuse_req *req; struct fuse_flush_in inarg; int err; if (is_bad_inode(inode)) return -EIO; if (fc->no_flush) return 0; req = fuse_get_req_nofail(fc, file); memset(&inarg, 0, sizeof(inarg)); inarg.fh = ff->fh; inarg.lock_owner = fuse_lock_owner_id(fc, id); req->in.h.opcode = FUSE_FLUSH; req->in.h.nodeid = get_node_id(inode); req->in.numargs = 1; req->in.args[0].size = sizeof(inarg); req->in.args[0].value = &inarg; req->force = 1; request_send(fc, req); err = req->out.h.error; fuse_put_request(fc, req); if (err == -ENOSYS) { fc->no_flush = 1; err = 0; } return err; } int fuse_fsync_common(struct file *file, struct dentry *de, int datasync, int isdir) { struct inode *inode = de->d_inode; struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_file *ff = file->private_data; struct fuse_req *req; struct fuse_fsync_in inarg; int err; if (is_bad_inode(inode)) return -EIO; if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir)) return 0; req = fuse_get_req(fc); if (IS_ERR(req)) return PTR_ERR(req); memset(&inarg, 0, sizeof(inarg)); inarg.fh = ff->fh; inarg.fsync_flags = datasync ? 1 : 0; req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC; req->in.h.nodeid = get_node_id(inode); req->in.numargs = 1; req->in.args[0].size = sizeof(inarg); req->in.args[0].value = &inarg; request_send(fc, req); err = req->out.h.error; fuse_put_request(fc, req); if (err == -ENOSYS) { if (isdir) fc->no_fsyncdir = 1; else fc->no_fsync = 1; err = 0; } return err; } static int fuse_fsync(struct file *file, struct dentry *de, int datasync) { return fuse_fsync_common(file, de, datasync, 0); } void fuse_read_fill(struct fuse_req *req, struct file *file, struct inode *inode, loff_t pos, size_t count, int opcode) { struct fuse_file *ff = file->private_data; struct fuse_read_in *inarg = &req->misc.read_in; inarg->fh = ff->fh; inarg->offset = pos; inarg->size = count; req->in.h.opcode = opcode; req->in.h.nodeid = get_node_id(inode); req->in.numargs = 1; req->in.args[0].size = sizeof(struct fuse_read_in); req->in.args[0].value = inarg; req->out.argpages = 1; req->out.argvar = 1; req->out.numargs = 1; req->out.args[0].size = count; } static size_t fuse_send_read(struct fuse_req *req, struct file *file, struct inode *inode, loff_t pos, size_t count) { struct fuse_conn *fc = get_fuse_conn(inode); fuse_read_fill(req, file, inode, pos, count, FUSE_READ); request_send(fc, req); return req->out.args[0].size; } static int fuse_readpage(struct file *file, struct page *page) { struct inode *inode = page->mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_req *req; int err; err = -EIO; if (is_bad_inode(inode)) goto out; req = fuse_get_req(fc); err = PTR_ERR(req); if (IS_ERR(req)) goto out; req->out.page_zeroing = 1; req->num_pages = 1; req->pages[0] = page; fuse_send_read(req, file, inode, page_offset(page), PAGE_CACHE_SIZE); err = req->out.h.error; fuse_put_request(fc, req); if (!err) SetPageUptodate(page); fuse_invalidate_attr(inode); /* atime changed */ out: unlock_page(page); return err; } static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req) { int i; fuse_invalidate_attr(req->pages[0]->mapping->host); /* atime changed */ for (i = 0; i < req->num_pages; i++) { struct page *page = req->pages[i]; if (!req->out.h.error) SetPageUptodate(page); else SetPageError(page); unlock_page(page); } fuse_put_request(fc, req); } static void fuse_send_readpages(struct fuse_req *req, struct file *file, struct inode *inode) { struct fuse_conn *fc = get_fuse_conn(inode); loff_t pos = page_offset(req->pages[0]); size_t count = req->num_pages << PAGE_CACHE_SHIFT; req->out.page_zeroing = 1; fuse_read_fill(req, file, inode, pos, count, FUSE_READ); if (fc->async_read) { get_file(file); req->file = file; req->end = fuse_readpages_end; request_send_background(fc, req); } else { request_send(fc, req); fuse_readpages_end(fc, req); } } struct fuse_readpages_data { struct fuse_req *req; struct file *file; struct inode *inode; }; static int fuse_readpages_fill(void *_data, struct page *page) { struct fuse_readpages_data *data = _data; struct fuse_req *req = data->req; struct inode *inode = data->inode; struct fuse_conn *fc = get_fuse_conn(inode); if (req->num_pages && (req->num_pages == FUSE_MAX_PAGES_PER_REQ || (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read || req->pages[req->num_pages - 1]->index + 1 != page->index)) { fuse_send_readpages(req, data->file, inode); data->req = req = fuse_get_req(fc); if (IS_ERR(req)) { unlock_page(page); return PTR_ERR(req); } } req->pages[req->num_pages] = page; req->num_pages ++; return 0; } static int fuse_readpages(struct file *file, struct address_space *mapping, struct list_head *pages, unsigned nr_pages) { struct inode *inode = mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_readpages_data data; int err; if (is_bad_inode(inode)) return -EIO; data.file = file; data.inode = inode; data.req = fuse_get_req(fc); if (IS_ERR(data.req)) return PTR_ERR(data.req); err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data); if (!err) { if (data.req->num_pages) fuse_send_readpages(data.req, file, inode); else fuse_put_request(fc, data.req); } return err; } static size_t fuse_send_write(struct fuse_req *req, struct file *file, struct inode *inode, loff_t pos, size_t count) { struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_file *ff = file->private_data; struct fuse_write_in inarg; struct fuse_write_out outarg; memset(&inarg, 0, sizeof(struct fuse_write_in)); inarg.fh = ff->fh; inarg.offset = pos; inarg.size = count; req->in.h.opcode = FUSE_WRITE; req->in.h.nodeid = get_node_id(inode); req->in.argpages = 1; req->in.numargs = 2; req->in.args[0].size = sizeof(struct fuse_write_in); req->in.args[0].value = &inarg; req->in.args[1].size = count; req->out.numargs = 1; req->out.args[0].size = sizeof(struct fuse_write_out); req->out.args[0].value = &outarg; request_send(fc, req); return outarg.size; } static int fuse_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to) { /* No op */ return 0; } static int fuse_commit_write(struct file *file, struct page *page, unsigned offset, unsigned to) { int err; size_t nres; unsigned count = to - offset; struct inode *inode = page->mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); loff_t pos = page_offset(page) + offset; struct fuse_req *req; if (is_bad_inode(inode)) return -EIO; req = fuse_get_req(fc); if (IS_ERR(req)) return PTR_ERR(req); req->num_pages = 1; req->pages[0] = page; req->page_offset = offset; nres = fuse_send_write(req, file, inode, pos, count); err = req->out.h.error; fuse_put_request(fc, req); if (!err && nres != count) err = -EIO; if (!err) { pos += count; if (pos > i_size_read(inode)) i_size_write(inode, pos); if (offset == 0 && to == PAGE_CACHE_SIZE) { clear_page_dirty(page); SetPageUptodate(page); } } fuse_invalidate_attr(inode); return err; } static void fuse_release_user_pages(struct fuse_req *req, int write) { unsigned i; for (i = 0; i < req->num_pages; i++) { struct page *page = req->pages[i]; if (write) set_page_dirty_lock(page); put_page(page); } } static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf, unsigned nbytes, int write) { unsigned long user_addr = (unsigned long) buf; unsigned offset = user_addr & ~PAGE_MASK; int npages; /* This doesn't work with nfsd */ if (!current->mm) return -EPERM; nbytes = min(nbytes, (unsigned) FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT); npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; npages = min(max(npages, 1), FUSE_MAX_PAGES_PER_REQ); down_read(¤t->mm->mmap_sem); npages = get_user_pages(current, current->mm, user_addr, npages, write, 0, req->pages, NULL); up_read(¤t->mm->mmap_sem); if (npages < 0) return npages; req->num_pages = npages; req->page_offset = offset; return 0; } static ssize_t fuse_direct_io(struct file *file, const char __user *buf, size_t count, loff_t *ppos, int write) { struct inode *inode = file->f_dentry->d_inode; struct fuse_conn *fc = get_fuse_conn(inode); size_t nmax = write ? fc->max_write : fc->max_read; loff_t pos = *ppos; ssize_t res = 0; struct fuse_req *req; if (is_bad_inode(inode)) return -EIO; req = fuse_get_req(fc); if (IS_ERR(req)) return PTR_ERR(req); while (count) { size_t nres; size_t nbytes = min(count, nmax); int err = fuse_get_user_pages(req, buf, nbytes, !write); if (err) { res = err; break; } nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset; nbytes = min(count, nbytes); if (write) nres = fuse_send_write(req, file, inode, pos, nbytes); else nres = fuse_send_read(req, file, inode, pos, nbytes); fuse_release_user_pages(req, !write); if (req->out.h.error) { if (!res) res = req->out.h.error; break; } else if (nres > nbytes) { res = -EIO; break; } count -= nres; res += nres; pos += nres; buf += nres; if (nres != nbytes) break; if (count) { fuse_put_request(fc, req); req = fuse_get_req(fc); if (IS_ERR(req)) break; } } fuse_put_request(fc, req); if (res > 0) { if (write && pos > i_size_read(inode)) i_size_write(inode, pos); *ppos = pos; } fuse_invalidate_attr(inode); return res; } static ssize_t fuse_direct_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { return fuse_direct_io(file, buf, count, ppos, 0); } static ssize_t fuse_direct_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { struct inode *inode = file->f_dentry->d_inode; ssize_t res; /* Don't allow parallel writes to the same file */ mutex_lock(&inode->i_mutex); res = fuse_direct_io(file, buf, count, ppos, 1); mutex_unlock(&inode->i_mutex); return res; } static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma) { if ((vma->vm_flags & VM_SHARED)) { if ((vma->vm_flags & VM_WRITE)) return -ENODEV; else vma->vm_flags &= ~VM_MAYWRITE; } return generic_file_mmap(file, vma); } static int fuse_set_page_dirty(struct page *page) { printk("fuse_set_page_dirty: should not happen\n"); dump_stack(); return 0; } static int convert_fuse_file_lock(const struct fuse_file_lock *ffl, struct file_lock *fl) { switch (ffl->type) { case F_UNLCK: break; case F_RDLCK: case F_WRLCK: if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX || ffl->end < ffl->start) return -EIO; fl->fl_start = ffl->start; fl->fl_end = ffl->end; fl->fl_pid = ffl->pid; break; default: return -EIO; } fl->fl_type = ffl->type; return 0; } static void fuse_lk_fill(struct fuse_req *req, struct file *file, const struct file_lock *fl, int opcode, pid_t pid) { struct inode *inode = file->f_dentry->d_inode; struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_file *ff = file->private_data; struct fuse_lk_in *arg = &req->misc.lk_in; arg->fh = ff->fh; arg->owner = fuse_lock_owner_id(fc, fl->fl_owner); arg->lk.start = fl->fl_start; arg->lk.end = fl->fl_end; arg->lk.type = fl->fl_type; arg->lk.pid = pid; req->in.h.opcode = opcode; req->in.h.nodeid = get_node_id(inode); req->in.numargs = 1; req->in.args[0].size = sizeof(*arg); req->in.args[0].value = arg; } static int fuse_getlk(struct file *file, struct file_lock *fl) { struct inode *inode = file->f_dentry->d_inode; struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_req *req; struct fuse_lk_out outarg; int err; req = fuse_get_req(fc); if (IS_ERR(req)) return PTR_ERR(req); fuse_lk_fill(req, file, fl, FUSE_GETLK, 0); req->out.numargs = 1; req->out.args[0].size = sizeof(outarg); req->out.args[0].value = &outarg; request_send(fc, req); err = req->out.h.error; fuse_put_request(fc, req); if (!err) err = convert_fuse_file_lock(&outarg.lk, fl); return err; } static int fuse_setlk(struct file *file, struct file_lock *fl) { struct inode *inode = file->f_dentry->d_inode; struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_req *req; int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK; pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0; int err; /* Unlock on close is handled by the flush method */ if (fl->fl_flags & FL_CLOSE) return 0; req = fuse_get_req(fc); if (IS_ERR(req)) return PTR_ERR(req); fuse_lk_fill(req, file, fl, opcode, pid); request_send(fc, req); err = req->out.h.error; /* locking is restartable */ if (err == -EINTR) err = -ERESTARTSYS; fuse_put_request(fc, req); return err; } static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl) { struct inode *inode = file->f_dentry->d_inode; struct fuse_conn *fc = get_fuse_conn(inode); int err; if (cmd == F_GETLK) { if (fc->no_lock) { if (!posix_test_lock(file, fl, fl)) fl->fl_type = F_UNLCK; err = 0; } else err = fuse_getlk(file, fl); } else { if (fc->no_lock) err = posix_lock_file_wait(file, fl); else err = fuse_setlk(file, fl); } return err; } static const struct file_operations fuse_file_operations = { .llseek = generic_file_llseek, .read = generic_file_read, .write = generic_file_write, .mmap = fuse_file_mmap, .open = fuse_open, .flush = fuse_flush, .release = fuse_release, .fsync = fuse_fsync, .lock = fuse_file_lock, .sendfile = generic_file_sendfile, }; static const struct file_operations fuse_direct_io_file_operations = { .llseek = generic_file_llseek, .read = fuse_direct_read, .write = fuse_direct_write, .open = fuse_open, .flush = fuse_flush, .release = fuse_release, .fsync = fuse_fsync, .lock = fuse_file_lock, /* no mmap and sendfile */ }; static const struct address_space_operations fuse_file_aops = { .readpage = fuse_readpage, .prepare_write = fuse_prepare_write, .commit_write = fuse_commit_write, .readpages = fuse_readpages, .set_page_dirty = fuse_set_page_dirty, }; void fuse_init_file_inode(struct inode *inode) { inode->i_fop = &fuse_file_operations; inode->i_data.a_ops = &fuse_file_aops; }