/* FUSE: Filesystem in Userspace Copyright (C) 2001-2008 Miklos Szeredi This program can be distributed under the terms of the GNU GPL. See the file COPYING. */ #include "fuse_i.h" #include #include #include #include #include #include #include #include #include #include static const struct file_operations fuse_direct_io_file_operations; static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file, int opcode, struct fuse_open_out *outargp) { struct fuse_open_in inarg; FUSE_ARGS(args); memset(&inarg, 0, sizeof(inarg)); inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY); if (!fc->atomic_o_trunc) inarg.flags &= ~O_TRUNC; args.in.h.opcode = opcode; args.in.h.nodeid = nodeid; args.in.numargs = 1; args.in.args[0].size = sizeof(inarg); args.in.args[0].value = &inarg; args.out.numargs = 1; args.out.args[0].size = sizeof(*outargp); args.out.args[0].value = outargp; return fuse_simple_request(fc, &args); } struct fuse_file *fuse_file_alloc(struct fuse_conn *fc) { struct fuse_file *ff; ff = kzalloc(sizeof(struct fuse_file), GFP_KERNEL); if (unlikely(!ff)) return NULL; ff->fc = fc; ff->reserved_req = fuse_request_alloc(0); if (unlikely(!ff->reserved_req)) { kfree(ff); return NULL; } INIT_LIST_HEAD(&ff->write_entry); mutex_init(&ff->readdir.lock); refcount_set(&ff->count, 1); RB_CLEAR_NODE(&ff->polled_node); init_waitqueue_head(&ff->poll_wait); ff->kh = atomic64_inc_return(&fc->khctr); return ff; } void fuse_file_free(struct fuse_file *ff) { fuse_request_free(ff->reserved_req); mutex_destroy(&ff->readdir.lock); kfree(ff); } static struct fuse_file *fuse_file_get(struct fuse_file *ff) { refcount_inc(&ff->count); return ff; } static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req) { iput(req->misc.release.inode); } static void fuse_file_put(struct fuse_file *ff, bool sync, bool isdir) { if (refcount_dec_and_test(&ff->count)) { struct fuse_req *req = ff->reserved_req; if (ff->fc->no_open && !isdir) { /* * Drop the release request when client does not * implement 'open' */ __clear_bit(FR_BACKGROUND, &req->flags); iput(req->misc.release.inode); fuse_put_request(ff->fc, req); } else if (sync) { __set_bit(FR_FORCE, &req->flags); __clear_bit(FR_BACKGROUND, &req->flags); fuse_request_send(ff->fc, req); iput(req->misc.release.inode); fuse_put_request(ff->fc, req); } else { req->end = fuse_release_end; __set_bit(FR_BACKGROUND, &req->flags); fuse_request_send_background(ff->fc, req); } kfree(ff); } } int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file, bool isdir) { struct fuse_file *ff; int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN; ff = fuse_file_alloc(fc); if (!ff) return -ENOMEM; ff->fh = 0; ff->open_flags = FOPEN_KEEP_CACHE; /* Default for no-open */ if (!fc->no_open || isdir) { struct fuse_open_out outarg; int err; err = fuse_send_open(fc, nodeid, file, opcode, &outarg); if (!err) { ff->fh = outarg.fh; ff->open_flags = outarg.open_flags; } else if (err != -ENOSYS || isdir) { fuse_file_free(ff); return err; } else { fc->no_open = 1; } } if (isdir) ff->open_flags &= ~FOPEN_DIRECT_IO; ff->nodeid = nodeid; file->private_data = ff; return 0; } EXPORT_SYMBOL_GPL(fuse_do_open); static void fuse_link_write_file(struct file *file) { struct inode *inode = file_inode(file); struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_file *ff = file->private_data; /* * file may be written through mmap, so chain it onto the * inodes's write_file list */ spin_lock(&fi->lock); if (list_empty(&ff->write_entry)) list_add(&ff->write_entry, &fi->write_files); spin_unlock(&fi->lock); } void fuse_finish_open(struct inode *inode, struct file *file) { struct fuse_file *ff = file->private_data; struct fuse_conn *fc = get_fuse_conn(inode); if (ff->open_flags & FOPEN_DIRECT_IO) file->f_op = &fuse_direct_io_file_operations; if (!(ff->open_flags & FOPEN_KEEP_CACHE)) invalidate_inode_pages2(inode->i_mapping); if (ff->open_flags & FOPEN_NONSEEKABLE) nonseekable_open(inode, file); if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) { struct fuse_inode *fi = get_fuse_inode(inode); spin_lock(&fi->lock); fi->attr_version = atomic64_inc_return(&fc->attr_version); i_size_write(inode, 0); spin_unlock(&fi->lock); fuse_invalidate_attr(inode); if (fc->writeback_cache) file_update_time(file); } if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache) fuse_link_write_file(file); } int fuse_open_common(struct inode *inode, struct file *file, bool isdir) { struct fuse_conn *fc = get_fuse_conn(inode); int err; bool lock_inode = (file->f_flags & O_TRUNC) && fc->atomic_o_trunc && fc->writeback_cache; err = generic_file_open(inode, file); if (err) return err; if (lock_inode) inode_lock(inode); err = fuse_do_open(fc, get_node_id(inode), file, isdir); if (!err) fuse_finish_open(inode, file); if (lock_inode) inode_unlock(inode); return err; } static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff, int flags, int opcode) { struct fuse_conn *fc = ff->fc; struct fuse_req *req = ff->reserved_req; struct fuse_release_in *inarg = &req->misc.release.in; /* Inode is NULL on error path of fuse_create_open() */ if (likely(fi)) { spin_lock(&fi->lock); list_del(&ff->write_entry); spin_unlock(&fi->lock); } spin_lock(&fc->lock); if (!RB_EMPTY_NODE(&ff->polled_node)) rb_erase(&ff->polled_node, &fc->polled_files); spin_unlock(&fc->lock); wake_up_interruptible_all(&ff->poll_wait); inarg->fh = ff->fh; inarg->flags = flags; req->in.h.opcode = opcode; req->in.h.nodeid = ff->nodeid; req->in.numargs = 1; req->in.args[0].size = sizeof(struct fuse_release_in); req->in.args[0].value = inarg; } void fuse_release_common(struct file *file, bool isdir) { struct fuse_inode *fi = get_fuse_inode(file_inode(file)); struct fuse_file *ff = file->private_data; struct fuse_req *req = ff->reserved_req; int opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE; fuse_prepare_release(fi, ff, file->f_flags, opcode); if (ff->flock) { struct fuse_release_in *inarg = &req->misc.release.in; inarg->release_flags |= FUSE_RELEASE_FLOCK_UNLOCK; inarg->lock_owner = fuse_lock_owner_id(ff->fc, (fl_owner_t) file); } /* Hold inode until release is finished */ req->misc.release.inode = igrab(file_inode(file)); /* * Normally this will send the RELEASE request, however if * some asynchronous READ or WRITE requests are outstanding, * the sending will be delayed. * * Make the release synchronous if this is a fuseblk mount, * synchronous RELEASE is allowed (and desirable) in this case * because the server can be trusted not to screw up. */ fuse_file_put(ff, ff->fc->destroy_req != NULL, isdir); } static int fuse_open(struct inode *inode, struct file *file) { return fuse_open_common(inode, file, false); } static int fuse_release(struct inode *inode, struct file *file) { struct fuse_conn *fc = get_fuse_conn(inode); /* see fuse_vma_close() for !writeback_cache case */ if (fc->writeback_cache) write_inode_now(inode, 1); fuse_release_common(file, false); /* return value is ignored by VFS */ return 0; } void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff, int flags) { WARN_ON(refcount_read(&ff->count) > 1); fuse_prepare_release(fi, ff, flags, FUSE_RELEASE); /* * iput(NULL) is a no-op and since the refcount is 1 and everything's * synchronous, we are fine with not doing igrab() here" */ fuse_file_put(ff, true, false); } EXPORT_SYMBOL_GPL(fuse_sync_release); /* * Scramble the ID space with XTEA, so that the value of the files_struct * pointer is not exposed to userspace. */ 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 struct fuse_req *fuse_find_writeback(struct fuse_inode *fi, pgoff_t idx_from, pgoff_t idx_to) { struct fuse_req *req; list_for_each_entry(req, &fi->writepages, writepages_entry) { pgoff_t curr_index; WARN_ON(get_fuse_inode(req->inode) != fi); curr_index = req->misc.write.in.offset >> PAGE_SHIFT; if (idx_from < curr_index + req->num_pages && curr_index <= idx_to) { return req; } } return NULL; } /* * Check if any page in a range is under writeback * * This is currently done by walking the list of writepage requests * for the inode, which can be pretty inefficient. */ static bool fuse_range_is_writeback(struct inode *inode, pgoff_t idx_from, pgoff_t idx_to) { struct fuse_inode *fi = get_fuse_inode(inode); bool found; spin_lock(&fi->lock); found = fuse_find_writeback(fi, idx_from, idx_to); spin_unlock(&fi->lock); return found; } static inline bool fuse_page_is_writeback(struct inode *inode, pgoff_t index) { return fuse_range_is_writeback(inode, index, index); } /* * Wait for page writeback to be completed. * * Since fuse doesn't rely on the VM writeback tracking, this has to * use some other means. */ static int fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index) { struct fuse_inode *fi = get_fuse_inode(inode); wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index)); return 0; } /* * Wait for all pending writepages on the inode to finish. * * This is currently done by blocking further writes with FUSE_NOWRITE * and waiting for all sent writes to complete. * * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage * could conflict with truncation. */ static void fuse_sync_writes(struct inode *inode) { fuse_set_nowrite(inode); fuse_release_nowrite(inode); } static int fuse_flush(struct file *file, fl_owner_t id) { struct inode *inode = file_inode(file); 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; err = write_inode_now(inode, 1); if (err) return err; inode_lock(inode); fuse_sync_writes(inode); inode_unlock(inode); err = filemap_check_errors(file->f_mapping); if (err) return err; req = fuse_get_req_nofail_nopages(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; __set_bit(FR_FORCE, &req->flags); fuse_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, loff_t start, loff_t end, int datasync, int opcode) { struct inode *inode = file->f_mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_file *ff = file->private_data; FUSE_ARGS(args); struct fuse_fsync_in inarg; memset(&inarg, 0, sizeof(inarg)); inarg.fh = ff->fh; inarg.fsync_flags = datasync ? 1 : 0; args.in.h.opcode = opcode; args.in.h.nodeid = get_node_id(inode); args.in.numargs = 1; args.in.args[0].size = sizeof(inarg); args.in.args[0].value = &inarg; return fuse_simple_request(fc, &args); } static int fuse_fsync(struct file *file, loff_t start, loff_t end, int datasync) { struct inode *inode = file->f_mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); int err; if (is_bad_inode(inode)) return -EIO; inode_lock(inode); /* * Start writeback against all dirty pages of the inode, then * wait for all outstanding writes, before sending the FSYNC * request. */ err = file_write_and_wait_range(file, start, end); if (err) goto out; fuse_sync_writes(inode); /* * Due to implementation of fuse writeback * file_write_and_wait_range() does not catch errors. * We have to do this directly after fuse_sync_writes() */ err = file_check_and_advance_wb_err(file); if (err) goto out; err = sync_inode_metadata(inode, 1); if (err) goto out; if (fc->no_fsync) goto out; err = fuse_fsync_common(file, start, end, datasync, FUSE_FSYNC); if (err == -ENOSYS) { fc->no_fsync = 1; err = 0; } out: inode_unlock(inode); return err; } void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos, size_t count, int opcode) { struct fuse_read_in *inarg = &req->misc.read.in; struct fuse_file *ff = file->private_data; inarg->fh = ff->fh; inarg->offset = pos; inarg->size = count; inarg->flags = file->f_flags; req->in.h.opcode = opcode; req->in.h.nodeid = ff->nodeid; req->in.numargs = 1; req->in.args[0].size = sizeof(struct fuse_read_in); req->in.args[0].value = inarg; req->out.argvar = 1; req->out.numargs = 1; req->out.args[0].size = count; } static void fuse_release_user_pages(struct fuse_req *req, bool should_dirty) { unsigned i; for (i = 0; i < req->num_pages; i++) { struct page *page = req->pages[i]; if (should_dirty) set_page_dirty_lock(page); put_page(page); } } static void fuse_io_release(struct kref *kref) { kfree(container_of(kref, struct fuse_io_priv, refcnt)); } static ssize_t fuse_get_res_by_io(struct fuse_io_priv *io) { if (io->err) return io->err; if (io->bytes >= 0 && io->write) return -EIO; return io->bytes < 0 ? io->size : io->bytes; } /** * In case of short read, the caller sets 'pos' to the position of * actual end of fuse request in IO request. Otherwise, if bytes_requested * == bytes_transferred or rw == WRITE, the caller sets 'pos' to -1. * * An example: * User requested DIO read of 64K. It was splitted into two 32K fuse requests, * both submitted asynchronously. The first of them was ACKed by userspace as * fully completed (req->out.args[0].size == 32K) resulting in pos == -1. The * second request was ACKed as short, e.g. only 1K was read, resulting in * pos == 33K. * * Thus, when all fuse requests are completed, the minimal non-negative 'pos' * will be equal to the length of the longest contiguous fragment of * transferred data starting from the beginning of IO request. */ static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos) { int left; spin_lock(&io->lock); if (err) io->err = io->err ? : err; else if (pos >= 0 && (io->bytes < 0 || pos < io->bytes)) io->bytes = pos; left = --io->reqs; if (!left && io->blocking) complete(io->done); spin_unlock(&io->lock); if (!left && !io->blocking) { ssize_t res = fuse_get_res_by_io(io); if (res >= 0) { struct inode *inode = file_inode(io->iocb->ki_filp); struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_inode *fi = get_fuse_inode(inode); spin_lock(&fi->lock); fi->attr_version = atomic64_inc_return(&fc->attr_version); spin_unlock(&fi->lock); } io->iocb->ki_complete(io->iocb, res, 0); } kref_put(&io->refcnt, fuse_io_release); } static void fuse_aio_complete_req(struct fuse_conn *fc, struct fuse_req *req) { struct fuse_io_priv *io = req->io; ssize_t pos = -1; fuse_release_user_pages(req, io->should_dirty); if (io->write) { if (req->misc.write.in.size != req->misc.write.out.size) pos = req->misc.write.in.offset - io->offset + req->misc.write.out.size; } else { if (req->misc.read.in.size != req->out.args[0].size) pos = req->misc.read.in.offset - io->offset + req->out.args[0].size; } fuse_aio_complete(io, req->out.h.error, pos); } static size_t fuse_async_req_send(struct fuse_conn *fc, struct fuse_req *req, size_t num_bytes, struct fuse_io_priv *io) { spin_lock(&io->lock); kref_get(&io->refcnt); io->size += num_bytes; io->reqs++; spin_unlock(&io->lock); req->io = io; req->end = fuse_aio_complete_req; __fuse_get_request(req); fuse_request_send_background(fc, req); return num_bytes; } static size_t fuse_send_read(struct fuse_req *req, struct fuse_io_priv *io, loff_t pos, size_t count, fl_owner_t owner) { struct file *file = io->iocb->ki_filp; struct fuse_file *ff = file->private_data; struct fuse_conn *fc = ff->fc; fuse_read_fill(req, file, pos, count, FUSE_READ); if (owner != NULL) { struct fuse_read_in *inarg = &req->misc.read.in; inarg->read_flags |= FUSE_READ_LOCKOWNER; inarg->lock_owner = fuse_lock_owner_id(fc, owner); } if (io->async) return fuse_async_req_send(fc, req, count, io); fuse_request_send(fc, req); return req->out.args[0].size; } static void fuse_read_update_size(struct inode *inode, loff_t size, u64 attr_ver) { struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_inode *fi = get_fuse_inode(inode); spin_lock(&fi->lock); if (attr_ver == fi->attr_version && size < inode->i_size && !test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) { fi->attr_version = atomic64_inc_return(&fc->attr_version); i_size_write(inode, size); } spin_unlock(&fi->lock); } static void fuse_short_read(struct fuse_req *req, struct inode *inode, u64 attr_ver) { size_t num_read = req->out.args[0].size; struct fuse_conn *fc = get_fuse_conn(inode); if (fc->writeback_cache) { /* * A hole in a file. Some data after the hole are in page cache, * but have not reached the client fs yet. So, the hole is not * present there. */ int i; int start_idx = num_read >> PAGE_SHIFT; size_t off = num_read & (PAGE_SIZE - 1); for (i = start_idx; i < req->num_pages; i++) { zero_user_segment(req->pages[i], off, PAGE_SIZE); off = 0; } } else { loff_t pos = page_offset(req->pages[0]) + num_read; fuse_read_update_size(inode, pos, attr_ver); } } static int fuse_do_readpage(struct file *file, struct page *page) { struct kiocb iocb; struct fuse_io_priv io; struct inode *inode = page->mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_req *req; size_t num_read; loff_t pos = page_offset(page); size_t count = PAGE_SIZE; u64 attr_ver; int err; /* * Page writeback can extend beyond the lifetime of the * page-cache page, so make sure we read a properly synced * page. */ fuse_wait_on_page_writeback(inode, page->index); req = fuse_get_req(fc, 1); if (IS_ERR(req)) return PTR_ERR(req); attr_ver = fuse_get_attr_version(fc); req->out.page_zeroing = 1; req->out.argpages = 1; req->num_pages = 1; req->pages[0] = page; req->page_descs[0].length = count; init_sync_kiocb(&iocb, file); io = (struct fuse_io_priv) FUSE_IO_PRIV_SYNC(&iocb); num_read = fuse_send_read(req, &io, pos, count, NULL); err = req->out.h.error; if (!err) { /* * Short read means EOF. If file size is larger, truncate it */ if (num_read < count) fuse_short_read(req, inode, attr_ver); SetPageUptodate(page); } fuse_put_request(fc, req); return err; } static int fuse_readpage(struct file *file, struct page *page) { struct inode *inode = page->mapping->host; int err; err = -EIO; if (is_bad_inode(inode)) goto out; err = fuse_do_readpage(file, page); fuse_invalidate_atime(inode); out: unlock_page(page); return err; } static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req) { int i; size_t count = req->misc.read.in.size; size_t num_read = req->out.args[0].size; struct address_space *mapping = NULL; for (i = 0; mapping == NULL && i < req->num_pages; i++) mapping = req->pages[i]->mapping; if (mapping) { struct inode *inode = mapping->host; /* * Short read means EOF. If file size is larger, truncate it */ if (!req->out.h.error && num_read < count) fuse_short_read(req, inode, req->misc.read.attr_ver); fuse_invalidate_atime(inode); } 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); put_page(page); } if (req->ff) fuse_file_put(req->ff, false, false); } static void fuse_send_readpages(struct fuse_req *req, struct file *file) { struct fuse_file *ff = file->private_data; struct fuse_conn *fc = ff->fc; loff_t pos = page_offset(req->pages[0]); size_t count = req->num_pages << PAGE_SHIFT; req->out.argpages = 1; req->out.page_zeroing = 1; req->out.page_replace = 1; fuse_read_fill(req, file, pos, count, FUSE_READ); req->misc.read.attr_ver = fuse_get_attr_version(fc); if (fc->async_read) { req->ff = fuse_file_get(ff); req->end = fuse_readpages_end; fuse_request_send_background(fc, req); } else { fuse_request_send(fc, req); fuse_readpages_end(fc, req); fuse_put_request(fc, req); } } struct fuse_fill_data { struct fuse_req *req; struct file *file; struct inode *inode; unsigned nr_pages; }; static int fuse_readpages_fill(void *_data, struct page *page) { struct fuse_fill_data *data = _data; struct fuse_req *req = data->req; struct inode *inode = data->inode; struct fuse_conn *fc = get_fuse_conn(inode); fuse_wait_on_page_writeback(inode, page->index); if (req->num_pages && (req->num_pages == fc->max_pages || (req->num_pages + 1) * PAGE_SIZE > fc->max_read || req->pages[req->num_pages - 1]->index + 1 != page->index)) { unsigned int nr_alloc = min_t(unsigned int, data->nr_pages, fc->max_pages); fuse_send_readpages(req, data->file); if (fc->async_read) req = fuse_get_req_for_background(fc, nr_alloc); else req = fuse_get_req(fc, nr_alloc); data->req = req; if (IS_ERR(req)) { unlock_page(page); return PTR_ERR(req); } } if (WARN_ON(req->num_pages >= req->max_pages)) { unlock_page(page); fuse_put_request(fc, req); return -EIO; } get_page(page); req->pages[req->num_pages] = page; req->page_descs[req->num_pages].length = PAGE_SIZE; req->num_pages++; data->nr_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_fill_data data; int err; unsigned int nr_alloc = min_t(unsigned int, nr_pages, fc->max_pages); err = -EIO; if (is_bad_inode(inode)) goto out; data.file = file; data.inode = inode; if (fc->async_read) data.req = fuse_get_req_for_background(fc, nr_alloc); else data.req = fuse_get_req(fc, nr_alloc); data.nr_pages = nr_pages; err = PTR_ERR(data.req); if (IS_ERR(data.req)) goto out; err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data); if (!err) { if (data.req->num_pages) fuse_send_readpages(data.req, file); else fuse_put_request(fc, data.req); } out: return err; } static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to) { struct inode *inode = iocb->ki_filp->f_mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); /* * In auto invalidate mode, always update attributes on read. * Otherwise, only update if we attempt to read past EOF (to ensure * i_size is up to date). */ if (fc->auto_inval_data || (iocb->ki_pos + iov_iter_count(to) > i_size_read(inode))) { int err; err = fuse_update_attributes(inode, iocb->ki_filp); if (err) return err; } return generic_file_read_iter(iocb, to); } static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff, loff_t pos, size_t count) { struct fuse_write_in *inarg = &req->misc.write.in; struct fuse_write_out *outarg = &req->misc.write.out; inarg->fh = ff->fh; inarg->offset = pos; inarg->size = count; req->in.h.opcode = FUSE_WRITE; req->in.h.nodeid = ff->nodeid; req->in.numargs = 2; if (ff->fc->minor < 9) req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE; else 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; } static size_t fuse_send_write(struct fuse_req *req, struct fuse_io_priv *io, loff_t pos, size_t count, fl_owner_t owner) { struct kiocb *iocb = io->iocb; struct file *file = iocb->ki_filp; struct fuse_file *ff = file->private_data; struct fuse_conn *fc = ff->fc; struct fuse_write_in *inarg = &req->misc.write.in; fuse_write_fill(req, ff, pos, count); inarg->flags = file->f_flags; if (iocb->ki_flags & IOCB_DSYNC) inarg->flags |= O_DSYNC; if (iocb->ki_flags & IOCB_SYNC) inarg->flags |= O_SYNC; if (owner != NULL) { inarg->write_flags |= FUSE_WRITE_LOCKOWNER; inarg->lock_owner = fuse_lock_owner_id(fc, owner); } if (io->async) return fuse_async_req_send(fc, req, count, io); fuse_request_send(fc, req); return req->misc.write.out.size; } bool fuse_write_update_size(struct inode *inode, loff_t pos) { struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_inode *fi = get_fuse_inode(inode); bool ret = false; spin_lock(&fi->lock); fi->attr_version = atomic64_inc_return(&fc->attr_version); if (pos > inode->i_size) { i_size_write(inode, pos); ret = true; } spin_unlock(&fi->lock); return ret; } static size_t fuse_send_write_pages(struct fuse_req *req, struct kiocb *iocb, struct inode *inode, loff_t pos, size_t count) { size_t res; unsigned offset; unsigned i; struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb); for (i = 0; i < req->num_pages; i++) fuse_wait_on_page_writeback(inode, req->pages[i]->index); res = fuse_send_write(req, &io, pos, count, NULL); offset = req->page_descs[0].offset; count = res; for (i = 0; i < req->num_pages; i++) { struct page *page = req->pages[i]; if (!req->out.h.error && !offset && count >= PAGE_SIZE) SetPageUptodate(page); if (count > PAGE_SIZE - offset) count -= PAGE_SIZE - offset; else count = 0; offset = 0; unlock_page(page); put_page(page); } return res; } static ssize_t fuse_fill_write_pages(struct fuse_req *req, struct address_space *mapping, struct iov_iter *ii, loff_t pos) { struct fuse_conn *fc = get_fuse_conn(mapping->host); unsigned offset = pos & (PAGE_SIZE - 1); size_t count = 0; int err; req->in.argpages = 1; req->page_descs[0].offset = offset; do { size_t tmp; struct page *page; pgoff_t index = pos >> PAGE_SHIFT; size_t bytes = min_t(size_t, PAGE_SIZE - offset, iov_iter_count(ii)); bytes = min_t(size_t, bytes, fc->max_write - count); again: err = -EFAULT; if (iov_iter_fault_in_readable(ii, bytes)) break; err = -ENOMEM; page = grab_cache_page_write_begin(mapping, index, 0); if (!page) break; if (mapping_writably_mapped(mapping)) flush_dcache_page(page); tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes); flush_dcache_page(page); iov_iter_advance(ii, tmp); if (!tmp) { unlock_page(page); put_page(page); bytes = min(bytes, iov_iter_single_seg_count(ii)); goto again; } err = 0; req->pages[req->num_pages] = page; req->page_descs[req->num_pages].length = tmp; req->num_pages++; count += tmp; pos += tmp; offset += tmp; if (offset == PAGE_SIZE) offset = 0; if (!fc->big_writes) break; } while (iov_iter_count(ii) && count < fc->max_write && req->num_pages < req->max_pages && offset == 0); return count > 0 ? count : err; } static inline unsigned int fuse_wr_pages(loff_t pos, size_t len, unsigned int max_pages) { return min_t(unsigned int, ((pos + len - 1) >> PAGE_SHIFT) - (pos >> PAGE_SHIFT) + 1, max_pages); } static ssize_t fuse_perform_write(struct kiocb *iocb, struct address_space *mapping, struct iov_iter *ii, loff_t pos) { struct inode *inode = mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_inode *fi = get_fuse_inode(inode); int err = 0; ssize_t res = 0; if (is_bad_inode(inode)) return -EIO; if (inode->i_size < pos + iov_iter_count(ii)) set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); do { struct fuse_req *req; ssize_t count; unsigned int nr_pages = fuse_wr_pages(pos, iov_iter_count(ii), fc->max_pages); req = fuse_get_req(fc, nr_pages); if (IS_ERR(req)) { err = PTR_ERR(req); break; } count = fuse_fill_write_pages(req, mapping, ii, pos); if (count <= 0) { err = count; } else { size_t num_written; num_written = fuse_send_write_pages(req, iocb, inode, pos, count); err = req->out.h.error; if (!err) { res += num_written; pos += num_written; /* break out of the loop on short write */ if (num_written != count) err = -EIO; } } fuse_put_request(fc, req); } while (!err && iov_iter_count(ii)); if (res > 0) fuse_write_update_size(inode, pos); clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); fuse_invalidate_attr(inode); return res > 0 ? res : err; } static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from) { struct file *file = iocb->ki_filp; struct address_space *mapping = file->f_mapping; ssize_t written = 0; ssize_t written_buffered = 0; struct inode *inode = mapping->host; ssize_t err; loff_t endbyte = 0; if (get_fuse_conn(inode)->writeback_cache) { /* Update size (EOF optimization) and mode (SUID clearing) */ err = fuse_update_attributes(mapping->host, file); if (err) return err; return generic_file_write_iter(iocb, from); } inode_lock(inode); /* We can write back this queue in page reclaim */ current->backing_dev_info = inode_to_bdi(inode); err = generic_write_checks(iocb, from); if (err <= 0) goto out; err = file_remove_privs(file); if (err) goto out; err = file_update_time(file); if (err) goto out; if (iocb->ki_flags & IOCB_DIRECT) { loff_t pos = iocb->ki_pos; written = generic_file_direct_write(iocb, from); if (written < 0 || !iov_iter_count(from)) goto out; pos += written; written_buffered = fuse_perform_write(iocb, mapping, from, pos); if (written_buffered < 0) { err = written_buffered; goto out; } endbyte = pos + written_buffered - 1; err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte); if (err) goto out; invalidate_mapping_pages(file->f_mapping, pos >> PAGE_SHIFT, endbyte >> PAGE_SHIFT); written += written_buffered; iocb->ki_pos = pos + written_buffered; } else { written = fuse_perform_write(iocb, mapping, from, iocb->ki_pos); if (written >= 0) iocb->ki_pos += written; } out: current->backing_dev_info = NULL; inode_unlock(inode); if (written > 0) written = generic_write_sync(iocb, written); return written ? written : err; } static inline void fuse_page_descs_length_init(struct fuse_req *req, unsigned index, unsigned nr_pages) { int i; for (i = index; i < index + nr_pages; i++) req->page_descs[i].length = PAGE_SIZE - req->page_descs[i].offset; } static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii) { return (unsigned long)ii->iov->iov_base + ii->iov_offset; } static inline size_t fuse_get_frag_size(const struct iov_iter *ii, size_t max_size) { return min(iov_iter_single_seg_count(ii), max_size); } static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii, size_t *nbytesp, int write) { size_t nbytes = 0; /* # bytes already packed in req */ ssize_t ret = 0; /* Special case for kernel I/O: can copy directly into the buffer */ if (iov_iter_is_kvec(ii)) { unsigned long user_addr = fuse_get_user_addr(ii); size_t frag_size = fuse_get_frag_size(ii, *nbytesp); if (write) req->in.args[1].value = (void *) user_addr; else req->out.args[0].value = (void *) user_addr; iov_iter_advance(ii, frag_size); *nbytesp = frag_size; return 0; } while (nbytes < *nbytesp && req->num_pages < req->max_pages) { unsigned npages; size_t start; ret = iov_iter_get_pages(ii, &req->pages[req->num_pages], *nbytesp - nbytes, req->max_pages - req->num_pages, &start); if (ret < 0) break; iov_iter_advance(ii, ret); nbytes += ret; ret += start; npages = (ret + PAGE_SIZE - 1) / PAGE_SIZE; req->page_descs[req->num_pages].offset = start; fuse_page_descs_length_init(req, req->num_pages, npages); req->num_pages += npages; req->page_descs[req->num_pages - 1].length -= (PAGE_SIZE - ret) & (PAGE_SIZE - 1); } if (write) req->in.argpages = 1; else req->out.argpages = 1; *nbytesp = nbytes; return ret < 0 ? ret : 0; } ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter, loff_t *ppos, int flags) { int write = flags & FUSE_DIO_WRITE; int cuse = flags & FUSE_DIO_CUSE; struct file *file = io->iocb->ki_filp; struct inode *inode = file->f_mapping->host; struct fuse_file *ff = file->private_data; struct fuse_conn *fc = ff->fc; size_t nmax = write ? fc->max_write : fc->max_read; loff_t pos = *ppos; size_t count = iov_iter_count(iter); pgoff_t idx_from = pos >> PAGE_SHIFT; pgoff_t idx_to = (pos + count - 1) >> PAGE_SHIFT; ssize_t res = 0; struct fuse_req *req; int err = 0; if (io->async) req = fuse_get_req_for_background(fc, iov_iter_npages(iter, fc->max_pages)); else req = fuse_get_req(fc, iov_iter_npages(iter, fc->max_pages)); if (IS_ERR(req)) return PTR_ERR(req); if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) { if (!write) inode_lock(inode); fuse_sync_writes(inode); if (!write) inode_unlock(inode); } io->should_dirty = !write && iter_is_iovec(iter); while (count) { size_t nres; fl_owner_t owner = current->files; size_t nbytes = min(count, nmax); err = fuse_get_user_pages(req, iter, &nbytes, write); if (err && !nbytes) break; if (write) nres = fuse_send_write(req, io, pos, nbytes, owner); else nres = fuse_send_read(req, io, pos, nbytes, owner); if (!io->async) fuse_release_user_pages(req, io->should_dirty); if (req->out.h.error) { err = req->out.h.error; break; } else if (nres > nbytes) { res = 0; err = -EIO; break; } count -= nres; res += nres; pos += nres; if (nres != nbytes) break; if (count) { fuse_put_request(fc, req); if (io->async) req = fuse_get_req_for_background(fc, iov_iter_npages(iter, fc->max_pages)); else req = fuse_get_req(fc, iov_iter_npages(iter, fc->max_pages)); if (IS_ERR(req)) break; } } if (!IS_ERR(req)) fuse_put_request(fc, req); if (res > 0) *ppos = pos; return res > 0 ? res : err; } EXPORT_SYMBOL_GPL(fuse_direct_io); static ssize_t __fuse_direct_read(struct fuse_io_priv *io, struct iov_iter *iter, loff_t *ppos) { ssize_t res; struct inode *inode = file_inode(io->iocb->ki_filp); if (is_bad_inode(inode)) return -EIO; res = fuse_direct_io(io, iter, ppos, 0); fuse_invalidate_atime(inode); return res; } static ssize_t fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter); static ssize_t fuse_direct_read_iter(struct kiocb *iocb, struct iov_iter *to) { ssize_t res; if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) { struct file *file = iocb->ki_filp; if (is_bad_inode(file_inode(file))) return -EIO; res = fuse_direct_IO(iocb, to); } else { struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb); res = __fuse_direct_read(&io, to, &iocb->ki_pos); } return res; } static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from) { struct inode *inode = file_inode(iocb->ki_filp); struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb); ssize_t res; if (is_bad_inode(inode)) return -EIO; /* Don't allow parallel writes to the same file */ inode_lock(inode); res = generic_write_checks(iocb, from); if (res > 0) { if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) { res = fuse_direct_IO(iocb, from); } else { res = fuse_direct_io(&io, from, &iocb->ki_pos, FUSE_DIO_WRITE); } } fuse_invalidate_attr(inode); if (res > 0) fuse_write_update_size(inode, iocb->ki_pos); inode_unlock(inode); return res; } static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req) { int i; for (i = 0; i < req->num_pages; i++) __free_page(req->pages[i]); if (req->ff) fuse_file_put(req->ff, false, false); } static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req) { struct inode *inode = req->inode; struct fuse_inode *fi = get_fuse_inode(inode); struct backing_dev_info *bdi = inode_to_bdi(inode); int i; list_del(&req->writepages_entry); for (i = 0; i < req->num_pages; i++) { dec_wb_stat(&bdi->wb, WB_WRITEBACK); dec_node_page_state(req->pages[i], NR_WRITEBACK_TEMP); wb_writeout_inc(&bdi->wb); } wake_up(&fi->page_waitq); } /* Called under fi->lock, may release and reacquire it */ static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req, loff_t size) __releases(fi->lock) __acquires(fi->lock) { struct fuse_req *aux, *next; struct fuse_inode *fi = get_fuse_inode(req->inode); struct fuse_write_in *inarg = &req->misc.write.in; __u64 data_size = req->num_pages * PAGE_SIZE; bool queued; if (inarg->offset + data_size <= size) { inarg->size = data_size; } else if (inarg->offset < size) { inarg->size = size - inarg->offset; } else { /* Got truncated off completely */ goto out_free; } req->in.args[1].size = inarg->size; queued = fuse_request_queue_background(fc, req); /* Fails on broken connection only */ if (unlikely(!queued)) goto out_free; fi->writectr++; return; out_free: fuse_writepage_finish(fc, req); spin_unlock(&fi->lock); /* After fuse_writepage_finish() aux request list is private */ for (aux = req->misc.write.next; aux; aux = next) { next = aux->misc.write.next; aux->misc.write.next = NULL; fuse_writepage_free(fc, aux); fuse_put_request(fc, aux); } fuse_writepage_free(fc, req); fuse_put_request(fc, req); spin_lock(&fi->lock); } /* * If fi->writectr is positive (no truncate or fsync going on) send * all queued writepage requests. * * Called with fi->lock */ void fuse_flush_writepages(struct inode *inode) __releases(fi->lock) __acquires(fi->lock) { struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_inode *fi = get_fuse_inode(inode); size_t crop = i_size_read(inode); struct fuse_req *req; while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) { req = list_entry(fi->queued_writes.next, struct fuse_req, list); list_del_init(&req->list); fuse_send_writepage(fc, req, crop); } } static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req) { struct inode *inode = req->inode; struct fuse_inode *fi = get_fuse_inode(inode); mapping_set_error(inode->i_mapping, req->out.h.error); spin_lock(&fi->lock); while (req->misc.write.next) { struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_write_in *inarg = &req->misc.write.in; struct fuse_req *next = req->misc.write.next; req->misc.write.next = next->misc.write.next; next->misc.write.next = NULL; next->ff = fuse_file_get(req->ff); list_add(&next->writepages_entry, &fi->writepages); /* * Skip fuse_flush_writepages() to make it easy to crop requests * based on primary request size. * * 1st case (trivial): there are no concurrent activities using * fuse_set/release_nowrite. Then we're on safe side because * fuse_flush_writepages() would call fuse_send_writepage() * anyway. * * 2nd case: someone called fuse_set_nowrite and it is waiting * now for completion of all in-flight requests. This happens * rarely and no more than once per page, so this should be * okay. * * 3rd case: someone (e.g. fuse_do_setattr()) is in the middle * of fuse_set_nowrite..fuse_release_nowrite section. The fact * that fuse_set_nowrite returned implies that all in-flight * requests were completed along with all of their secondary * requests. Further primary requests are blocked by negative * writectr. Hence there cannot be any in-flight requests and * no invocations of fuse_writepage_end() while we're in * fuse_set_nowrite..fuse_release_nowrite section. */ fuse_send_writepage(fc, next, inarg->offset + inarg->size); } fi->writectr--; fuse_writepage_finish(fc, req); spin_unlock(&fi->lock); fuse_writepage_free(fc, req); } static struct fuse_file *__fuse_write_file_get(struct fuse_conn *fc, struct fuse_inode *fi) { struct fuse_file *ff = NULL; spin_lock(&fi->lock); if (!list_empty(&fi->write_files)) { ff = list_entry(fi->write_files.next, struct fuse_file, write_entry); fuse_file_get(ff); } spin_unlock(&fi->lock); return ff; } static struct fuse_file *fuse_write_file_get(struct fuse_conn *fc, struct fuse_inode *fi) { struct fuse_file *ff = __fuse_write_file_get(fc, fi); WARN_ON(!ff); return ff; } int fuse_write_inode(struct inode *inode, struct writeback_control *wbc) { struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_file *ff; int err; ff = __fuse_write_file_get(fc, fi); err = fuse_flush_times(inode, ff); if (ff) fuse_file_put(ff, false, false); return err; } static int fuse_writepage_locked(struct page *page) { struct address_space *mapping = page->mapping; struct inode *inode = mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_req *req; struct page *tmp_page; int error = -ENOMEM; set_page_writeback(page); req = fuse_request_alloc_nofs(1); if (!req) goto err; /* writeback always goes to bg_queue */ __set_bit(FR_BACKGROUND, &req->flags); tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); if (!tmp_page) goto err_free; error = -EIO; req->ff = fuse_write_file_get(fc, fi); if (!req->ff) goto err_nofile; fuse_write_fill(req, req->ff, page_offset(page), 0); copy_highpage(tmp_page, page); req->misc.write.in.write_flags |= FUSE_WRITE_CACHE; req->misc.write.next = NULL; req->in.argpages = 1; req->num_pages = 1; req->pages[0] = tmp_page; req->page_descs[0].offset = 0; req->page_descs[0].length = PAGE_SIZE; req->end = fuse_writepage_end; req->inode = inode; inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK); inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP); spin_lock(&fi->lock); list_add(&req->writepages_entry, &fi->writepages); list_add_tail(&req->list, &fi->queued_writes); fuse_flush_writepages(inode); spin_unlock(&fi->lock); end_page_writeback(page); return 0; err_nofile: __free_page(tmp_page); err_free: fuse_request_free(req); err: mapping_set_error(page->mapping, error); end_page_writeback(page); return error; } static int fuse_writepage(struct page *page, struct writeback_control *wbc) { int err; if (fuse_page_is_writeback(page->mapping->host, page->index)) { /* * ->writepages() should be called for sync() and friends. We * should only get here on direct reclaim and then we are * allowed to skip a page which is already in flight */ WARN_ON(wbc->sync_mode == WB_SYNC_ALL); redirty_page_for_writepage(wbc, page); return 0; } err = fuse_writepage_locked(page); unlock_page(page); return err; } struct fuse_fill_wb_data { struct fuse_req *req; struct fuse_file *ff; struct inode *inode; struct page **orig_pages; }; static void fuse_writepages_send(struct fuse_fill_wb_data *data) { struct fuse_req *req = data->req; struct inode *inode = data->inode; struct fuse_inode *fi = get_fuse_inode(inode); int num_pages = req->num_pages; int i; req->ff = fuse_file_get(data->ff); spin_lock(&fi->lock); list_add_tail(&req->list, &fi->queued_writes); fuse_flush_writepages(inode); spin_unlock(&fi->lock); for (i = 0; i < num_pages; i++) end_page_writeback(data->orig_pages[i]); } /* * First recheck under fi->lock if the offending offset is still under * writeback. If yes, then iterate auxiliary write requests, to see if there's * one already added for a page at this offset. If there's none, then insert * this new request onto the auxiliary list, otherwise reuse the existing one by * copying the new page contents over to the old temporary page. */ static bool fuse_writepage_in_flight(struct fuse_req *new_req, struct page *page) { struct fuse_conn *fc = get_fuse_conn(new_req->inode); struct fuse_inode *fi = get_fuse_inode(new_req->inode); struct fuse_req *tmp; struct fuse_req *old_req; WARN_ON(new_req->num_pages != 0); spin_lock(&fi->lock); list_del(&new_req->writepages_entry); old_req = fuse_find_writeback(fi, page->index, page->index); if (!old_req) { list_add(&new_req->writepages_entry, &fi->writepages); spin_unlock(&fi->lock); return false; } new_req->num_pages = 1; for (tmp = old_req->misc.write.next; tmp; tmp = tmp->misc.write.next) { pgoff_t curr_index; WARN_ON(tmp->inode != new_req->inode); curr_index = tmp->misc.write.in.offset >> PAGE_SHIFT; if (curr_index == page->index) { WARN_ON(tmp->num_pages != 1); WARN_ON(!test_bit(FR_PENDING, &tmp->flags)); swap(tmp->pages[0], new_req->pages[0]); break; } } if (!tmp) { new_req->misc.write.next = old_req->misc.write.next; old_req->misc.write.next = new_req; } spin_unlock(&fi->lock); if (tmp) { struct backing_dev_info *bdi = inode_to_bdi(new_req->inode); dec_wb_stat(&bdi->wb, WB_WRITEBACK); dec_node_page_state(new_req->pages[0], NR_WRITEBACK_TEMP); wb_writeout_inc(&bdi->wb); fuse_writepage_free(fc, new_req); fuse_request_free(new_req); } return true; } static int fuse_writepages_fill(struct page *page, struct writeback_control *wbc, void *_data) { struct fuse_fill_wb_data *data = _data; struct fuse_req *req = data->req; struct inode *inode = data->inode; struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_conn *fc = get_fuse_conn(inode); struct page *tmp_page; bool is_writeback; int err; if (!data->ff) { err = -EIO; data->ff = fuse_write_file_get(fc, get_fuse_inode(inode)); if (!data->ff) goto out_unlock; } /* * Being under writeback is unlikely but possible. For example direct * read to an mmaped fuse file will set the page dirty twice; once when * the pages are faulted with get_user_pages(), and then after the read * completed. */ is_writeback = fuse_page_is_writeback(inode, page->index); if (req && req->num_pages && (is_writeback || req->num_pages == fc->max_pages || (req->num_pages + 1) * PAGE_SIZE > fc->max_write || data->orig_pages[req->num_pages - 1]->index + 1 != page->index)) { fuse_writepages_send(data); data->req = NULL; } else if (req && req->num_pages == req->max_pages) { if (!fuse_req_realloc_pages(fc, req, GFP_NOFS)) { fuse_writepages_send(data); req = data->req = NULL; } } err = -ENOMEM; tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); if (!tmp_page) goto out_unlock; /* * The page must not be redirtied until the writeout is completed * (i.e. userspace has sent a reply to the write request). Otherwise * there could be more than one temporary page instance for each real * page. * * This is ensured by holding the page lock in page_mkwrite() while * checking fuse_page_is_writeback(). We already hold the page lock * since clear_page_dirty_for_io() and keep it held until we add the * request to the fi->writepages list and increment req->num_pages. * After this fuse_page_is_writeback() will indicate that the page is * under writeback, so we can release the page lock. */ if (data->req == NULL) { struct fuse_inode *fi = get_fuse_inode(inode); err = -ENOMEM; req = fuse_request_alloc_nofs(FUSE_REQ_INLINE_PAGES); if (!req) { __free_page(tmp_page); goto out_unlock; } fuse_write_fill(req, data->ff, page_offset(page), 0); req->misc.write.in.write_flags |= FUSE_WRITE_CACHE; req->misc.write.next = NULL; req->in.argpages = 1; __set_bit(FR_BACKGROUND, &req->flags); req->num_pages = 0; req->end = fuse_writepage_end; req->inode = inode; spin_lock(&fi->lock); list_add(&req->writepages_entry, &fi->writepages); spin_unlock(&fi->lock); data->req = req; } set_page_writeback(page); copy_highpage(tmp_page, page); req->pages[req->num_pages] = tmp_page; req->page_descs[req->num_pages].offset = 0; req->page_descs[req->num_pages].length = PAGE_SIZE; inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK); inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP); err = 0; if (is_writeback && fuse_writepage_in_flight(req, page)) { end_page_writeback(page); data->req = NULL; goto out_unlock; } data->orig_pages[req->num_pages] = page; /* * Protected by fi->lock against concurrent access by * fuse_page_is_writeback(). */ spin_lock(&fi->lock); req->num_pages++; spin_unlock(&fi->lock); out_unlock: unlock_page(page); return err; } static int fuse_writepages(struct address_space *mapping, struct writeback_control *wbc) { struct inode *inode = mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_fill_wb_data data; int err; err = -EIO; if (is_bad_inode(inode)) goto out; data.inode = inode; data.req = NULL; data.ff = NULL; err = -ENOMEM; data.orig_pages = kcalloc(fc->max_pages, sizeof(struct page *), GFP_NOFS); if (!data.orig_pages) goto out; err = write_cache_pages(mapping, wbc, fuse_writepages_fill, &data); if (data.req) { /* Ignore errors if we can write at least one page */ BUG_ON(!data.req->num_pages); fuse_writepages_send(&data); err = 0; } if (data.ff) fuse_file_put(data.ff, false, false); kfree(data.orig_pages); out: return err; } /* * It's worthy to make sure that space is reserved on disk for the write, * but how to implement it without killing performance need more thinking. */ static int fuse_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) { pgoff_t index = pos >> PAGE_SHIFT; struct fuse_conn *fc = get_fuse_conn(file_inode(file)); struct page *page; loff_t fsize; int err = -ENOMEM; WARN_ON(!fc->writeback_cache); page = grab_cache_page_write_begin(mapping, index, flags); if (!page) goto error; fuse_wait_on_page_writeback(mapping->host, page->index); if (PageUptodate(page) || len == PAGE_SIZE) goto success; /* * Check if the start this page comes after the end of file, in which * case the readpage can be optimized away. */ fsize = i_size_read(mapping->host); if (fsize <= (pos & PAGE_MASK)) { size_t off = pos & ~PAGE_MASK; if (off) zero_user_segment(page, 0, off); goto success; } err = fuse_do_readpage(file, page); if (err) goto cleanup; success: *pagep = page; return 0; cleanup: unlock_page(page); put_page(page); error: return err; } static int fuse_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { struct inode *inode = page->mapping->host; /* Haven't copied anything? Skip zeroing, size extending, dirtying. */ if (!copied) goto unlock; if (!PageUptodate(page)) { /* Zero any unwritten bytes at the end of the page */ size_t endoff = (pos + copied) & ~PAGE_MASK; if (endoff) zero_user_segment(page, endoff, PAGE_SIZE); SetPageUptodate(page); } fuse_write_update_size(inode, pos + copied); set_page_dirty(page); unlock: unlock_page(page); put_page(page); return copied; } static int fuse_launder_page(struct page *page) { int err = 0; if (clear_page_dirty_for_io(page)) { struct inode *inode = page->mapping->host; err = fuse_writepage_locked(page); if (!err) fuse_wait_on_page_writeback(inode, page->index); } return err; } /* * Write back dirty pages now, because there may not be any suitable * open files later */ static void fuse_vma_close(struct vm_area_struct *vma) { filemap_write_and_wait(vma->vm_file->f_mapping); } /* * Wait for writeback against this page to complete before allowing it * to be marked dirty again, and hence written back again, possibly * before the previous writepage completed. * * Block here, instead of in ->writepage(), so that the userspace fs * can only block processes actually operating on the filesystem. * * Otherwise unprivileged userspace fs would be able to block * unrelated: * * - page migration * - sync(2) * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER */ static vm_fault_t fuse_page_mkwrite(struct vm_fault *vmf) { struct page *page = vmf->page; struct inode *inode = file_inode(vmf->vma->vm_file); file_update_time(vmf->vma->vm_file); lock_page(page); if (page->mapping != inode->i_mapping) { unlock_page(page); return VM_FAULT_NOPAGE; } fuse_wait_on_page_writeback(inode, page->index); return VM_FAULT_LOCKED; } static const struct vm_operations_struct fuse_file_vm_ops = { .close = fuse_vma_close, .fault = filemap_fault, .map_pages = filemap_map_pages, .page_mkwrite = fuse_page_mkwrite, }; static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma) { if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) fuse_link_write_file(file); file_accessed(file); vma->vm_ops = &fuse_file_vm_ops; return 0; } static int fuse_direct_mmap(struct file *file, struct vm_area_struct *vma) { /* Can't provide the coherency needed for MAP_SHARED */ if (vma->vm_flags & VM_MAYSHARE) return -ENODEV; invalidate_inode_pages2(file->f_mapping); return generic_file_mmap(file, vma); } static int convert_fuse_file_lock(struct fuse_conn *fc, 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; /* * Convert pid into init's pid namespace. The locks API will * translate it into the caller's pid namespace. */ rcu_read_lock(); fl->fl_pid = pid_nr_ns(find_pid_ns(ffl->pid, fc->pid_ns), &init_pid_ns); rcu_read_unlock(); break; default: return -EIO; } fl->fl_type = ffl->type; return 0; } static void fuse_lk_fill(struct fuse_args *args, struct file *file, const struct file_lock *fl, int opcode, pid_t pid, int flock, struct fuse_lk_in *inarg) { struct inode *inode = file_inode(file); struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_file *ff = file->private_data; memset(inarg, 0, sizeof(*inarg)); inarg->fh = ff->fh; inarg->owner = fuse_lock_owner_id(fc, fl->fl_owner); inarg->lk.start = fl->fl_start; inarg->lk.end = fl->fl_end; inarg->lk.type = fl->fl_type; inarg->lk.pid = pid; if (flock) inarg->lk_flags |= FUSE_LK_FLOCK; args->in.h.opcode = opcode; args->in.h.nodeid = get_node_id(inode); args->in.numargs = 1; args->in.args[0].size = sizeof(*inarg); args->in.args[0].value = inarg; } static int fuse_getlk(struct file *file, struct file_lock *fl) { struct inode *inode = file_inode(file); struct fuse_conn *fc = get_fuse_conn(inode); FUSE_ARGS(args); struct fuse_lk_in inarg; struct fuse_lk_out outarg; int err; fuse_lk_fill(&args, file, fl, FUSE_GETLK, 0, 0, &inarg); 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) err = convert_fuse_file_lock(fc, &outarg.lk, fl); return err; } static int fuse_setlk(struct file *file, struct file_lock *fl, int flock) { struct inode *inode = file_inode(file); struct fuse_conn *fc = get_fuse_conn(inode); FUSE_ARGS(args); struct fuse_lk_in inarg; int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK; struct pid *pid = fl->fl_type != F_UNLCK ? task_tgid(current) : NULL; pid_t pid_nr = pid_nr_ns(pid, fc->pid_ns); int err; if (fl->fl_lmops && fl->fl_lmops->lm_grant) { /* NLM needs asynchronous locks, which we don't support yet */ return -ENOLCK; } /* Unlock on close is handled by the flush method */ if ((fl->fl_flags & FL_CLOSE_POSIX) == FL_CLOSE_POSIX) return 0; fuse_lk_fill(&args, file, fl, opcode, pid_nr, flock, &inarg); err = fuse_simple_request(fc, &args); /* locking is restartable */ if (err == -EINTR) err = -ERESTARTSYS; return err; } static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl) { struct inode *inode = file_inode(file); struct fuse_conn *fc = get_fuse_conn(inode); int err; if (cmd == F_CANCELLK) { err = 0; } else if (cmd == F_GETLK) { if (fc->no_lock) { posix_test_lock(file, fl); err = 0; } else err = fuse_getlk(file, fl); } else { if (fc->no_lock) err = posix_lock_file(file, fl, NULL); else err = fuse_setlk(file, fl, 0); } return err; } static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl) { struct inode *inode = file_inode(file); struct fuse_conn *fc = get_fuse_conn(inode); int err; if (fc->no_flock) { err = locks_lock_file_wait(file, fl); } else { struct fuse_file *ff = file->private_data; /* emulate flock with POSIX locks */ ff->flock = true; err = fuse_setlk(file, fl, 1); } return err; } static sector_t fuse_bmap(struct address_space *mapping, sector_t block) { struct inode *inode = mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); FUSE_ARGS(args); struct fuse_bmap_in inarg; struct fuse_bmap_out outarg; int err; if (!inode->i_sb->s_bdev || fc->no_bmap) return 0; memset(&inarg, 0, sizeof(inarg)); inarg.block = block; inarg.blocksize = inode->i_sb->s_blocksize; args.in.h.opcode = FUSE_BMAP; args.in.h.nodeid = get_node_id(inode); args.in.numargs = 1; args.in.args[0].size = sizeof(inarg); args.in.args[0].value = &inarg; 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 == -ENOSYS) fc->no_bmap = 1; return err ? 0 : outarg.block; } static loff_t fuse_lseek(struct file *file, loff_t offset, int whence) { struct inode *inode = file->f_mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_file *ff = file->private_data; FUSE_ARGS(args); struct fuse_lseek_in inarg = { .fh = ff->fh, .offset = offset, .whence = whence }; struct fuse_lseek_out outarg; int err; if (fc->no_lseek) goto fallback; args.in.h.opcode = FUSE_LSEEK; args.in.h.nodeid = ff->nodeid; args.in.numargs = 1; args.in.args[0].size = sizeof(inarg); args.in.args[0].value = &inarg; 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) { if (err == -ENOSYS) { fc->no_lseek = 1; goto fallback; } return err; } return vfs_setpos(file, outarg.offset, inode->i_sb->s_maxbytes); fallback: err = fuse_update_attributes(inode, file); if (!err) return generic_file_llseek(file, offset, whence); else return err; } static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence) { loff_t retval; struct inode *inode = file_inode(file); switch (whence) { case SEEK_SET: case SEEK_CUR: /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */ retval = generic_file_llseek(file, offset, whence); break; case SEEK_END: inode_lock(inode); retval = fuse_update_attributes(inode, file); if (!retval) retval = generic_file_llseek(file, offset, whence); inode_unlock(inode); break; case SEEK_HOLE: case SEEK_DATA: inode_lock(inode); retval = fuse_lseek(file, offset, whence); inode_unlock(inode); break; default: retval = -EINVAL; } return retval; } /* * CUSE servers compiled on 32bit broke on 64bit kernels because the * ABI was defined to be 'struct iovec' which is different on 32bit * and 64bit. Fortunately we can determine which structure the server * used from the size of the reply. */ static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src, size_t transferred, unsigned count, bool is_compat) { #ifdef CONFIG_COMPAT if (count * sizeof(struct compat_iovec) == transferred) { struct compat_iovec *ciov = src; unsigned i; /* * With this interface a 32bit server cannot support * non-compat (i.e. ones coming from 64bit apps) ioctl * requests */ if (!is_compat) return -EINVAL; for (i = 0; i < count; i++) { dst[i].iov_base = compat_ptr(ciov[i].iov_base); dst[i].iov_len = ciov[i].iov_len; } return 0; } #endif if (count * sizeof(struct iovec) != transferred) return -EIO; memcpy(dst, src, transferred); return 0; } /* Make sure iov_length() won't overflow */ static int fuse_verify_ioctl_iov(struct fuse_conn *fc, struct iovec *iov, size_t count) { size_t n; u32 max = fc->max_pages << PAGE_SHIFT; for (n = 0; n < count; n++, iov++) { if (iov->iov_len > (size_t) max) return -ENOMEM; max -= iov->iov_len; } return 0; } static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst, void *src, size_t transferred, unsigned count, bool is_compat) { unsigned i; struct fuse_ioctl_iovec *fiov = src; if (fc->minor < 16) { return fuse_copy_ioctl_iovec_old(dst, src, transferred, count, is_compat); } if (count * sizeof(struct fuse_ioctl_iovec) != transferred) return -EIO; for (i = 0; i < count; i++) { /* Did the server supply an inappropriate value? */ if (fiov[i].base != (unsigned long) fiov[i].base || fiov[i].len != (unsigned long) fiov[i].len) return -EIO; dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base; dst[i].iov_len = (size_t) fiov[i].len; #ifdef CONFIG_COMPAT if (is_compat && (ptr_to_compat(dst[i].iov_base) != fiov[i].base || (compat_size_t) dst[i].iov_len != fiov[i].len)) return -EIO; #endif } return 0; } /* * For ioctls, there is no generic way to determine how much memory * needs to be read and/or written. Furthermore, ioctls are allowed * to dereference the passed pointer, so the parameter requires deep * copying but FUSE has no idea whatsoever about what to copy in or * out. * * This is solved by allowing FUSE server to retry ioctl with * necessary in/out iovecs. Let's assume the ioctl implementation * needs to read in the following structure. * * struct a { * char *buf; * size_t buflen; * } * * On the first callout to FUSE server, inarg->in_size and * inarg->out_size will be NULL; then, the server completes the ioctl * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and * the actual iov array to * * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) } } * * which tells FUSE to copy in the requested area and retry the ioctl. * On the second round, the server has access to the structure and * from that it can tell what to look for next, so on the invocation, * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to * * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) }, * { .iov_base = a.buf, .iov_len = a.buflen } } * * FUSE will copy both struct a and the pointed buffer from the * process doing the ioctl and retry ioctl with both struct a and the * buffer. * * This time, FUSE server has everything it needs and completes ioctl * without FUSE_IOCTL_RETRY which finishes the ioctl call. * * Copying data out works the same way. * * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel * automatically initializes in and out iovs by decoding @cmd with * _IOC_* macros and the server is not allowed to request RETRY. This * limits ioctl data transfers to well-formed ioctls and is the forced * behavior for all FUSE servers. */ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg, unsigned int flags) { struct fuse_file *ff = file->private_data; struct fuse_conn *fc = ff->fc; struct fuse_ioctl_in inarg = { .fh = ff->fh, .cmd = cmd, .arg = arg, .flags = flags }; struct fuse_ioctl_out outarg; struct fuse_req *req = NULL; struct page **pages = NULL; struct iovec *iov_page = NULL; struct iovec *in_iov = NULL, *out_iov = NULL; unsigned int in_iovs = 0, out_iovs = 0, num_pages = 0, max_pages; size_t in_size, out_size, transferred, c; int err, i; struct iov_iter ii; #if BITS_PER_LONG == 32 inarg.flags |= FUSE_IOCTL_32BIT; #else if (flags & FUSE_IOCTL_COMPAT) inarg.flags |= FUSE_IOCTL_32BIT; #endif /* assume all the iovs returned by client always fits in a page */ BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE); err = -ENOMEM; pages = kcalloc(fc->max_pages, sizeof(pages[0]), GFP_KERNEL); iov_page = (struct iovec *) __get_free_page(GFP_KERNEL); if (!pages || !iov_page) goto out; /* * If restricted, initialize IO parameters as encoded in @cmd. * RETRY from server is not allowed. */ if (!(flags & FUSE_IOCTL_UNRESTRICTED)) { struct iovec *iov = iov_page; iov->iov_base = (void __user *)arg; iov->iov_len = _IOC_SIZE(cmd); if (_IOC_DIR(cmd) & _IOC_WRITE) { in_iov = iov; in_iovs = 1; } if (_IOC_DIR(cmd) & _IOC_READ) { out_iov = iov; out_iovs = 1; } } retry: inarg.in_size = in_size = iov_length(in_iov, in_iovs); inarg.out_size = out_size = iov_length(out_iov, out_iovs); /* * Out data can be used either for actual out data or iovs, * make sure there always is at least one page. */ out_size = max_t(size_t, out_size, PAGE_SIZE); max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE); /* make sure there are enough buffer pages and init request with them */ err = -ENOMEM; if (max_pages > fc->max_pages) goto out; while (num_pages < max_pages) { pages[num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM); if (!pages[num_pages]) goto out; num_pages++; } req = fuse_get_req(fc, num_pages); if (IS_ERR(req)) { err = PTR_ERR(req); req = NULL; goto out; } memcpy(req->pages, pages, sizeof(req->pages[0]) * num_pages); req->num_pages = num_pages; fuse_page_descs_length_init(req, 0, req->num_pages); /* okay, let's send it to the client */ req->in.h.opcode = FUSE_IOCTL; req->in.h.nodeid = ff->nodeid; req->in.numargs = 1; req->in.args[0].size = sizeof(inarg); req->in.args[0].value = &inarg; if (in_size) { req->in.numargs++; req->in.args[1].size = in_size; req->in.argpages = 1; err = -EFAULT; iov_iter_init(&ii, WRITE, in_iov, in_iovs, in_size); for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= num_pages); i++) { c = copy_page_from_iter(pages[i], 0, PAGE_SIZE, &ii); if (c != PAGE_SIZE && iov_iter_count(&ii)) goto out; } } req->out.numargs = 2; req->out.args[0].size = sizeof(outarg); req->out.args[0].value = &outarg; req->out.args[1].size = out_size; req->out.argpages = 1; req->out.argvar = 1; fuse_request_send(fc, req); err = req->out.h.error; transferred = req->out.args[1].size; fuse_put_request(fc, req); req = NULL; if (err) goto out; /* did it ask for retry? */ if (outarg.flags & FUSE_IOCTL_RETRY) { void *vaddr; /* no retry if in restricted mode */ err = -EIO; if (!(flags & FUSE_IOCTL_UNRESTRICTED)) goto out; in_iovs = outarg.in_iovs; out_iovs = outarg.out_iovs; /* * Make sure things are in boundary, separate checks * are to protect against overflow. */ err = -ENOMEM; if (in_iovs > FUSE_IOCTL_MAX_IOV || out_iovs > FUSE_IOCTL_MAX_IOV || in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV) goto out; vaddr = kmap_atomic(pages[0]); err = fuse_copy_ioctl_iovec(fc, iov_page, vaddr, transferred, in_iovs + out_iovs, (flags & FUSE_IOCTL_COMPAT) != 0); kunmap_atomic(vaddr); if (err) goto out; in_iov = iov_page; out_iov = in_iov + in_iovs; err = fuse_verify_ioctl_iov(fc, in_iov, in_iovs); if (err) goto out; err = fuse_verify_ioctl_iov(fc, out_iov, out_iovs); if (err) goto out; goto retry; } err = -EIO; if (transferred > inarg.out_size) goto out; err = -EFAULT; iov_iter_init(&ii, READ, out_iov, out_iovs, transferred); for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= num_pages); i++) { c = copy_page_to_iter(pages[i], 0, PAGE_SIZE, &ii); if (c != PAGE_SIZE && iov_iter_count(&ii)) goto out; } err = 0; out: if (req) fuse_put_request(fc, req); free_page((unsigned long) iov_page); while (num_pages) __free_page(pages[--num_pages]); kfree(pages); return err ? err : outarg.result; } EXPORT_SYMBOL_GPL(fuse_do_ioctl); long fuse_ioctl_common(struct file *file, unsigned int cmd, unsigned long arg, unsigned int flags) { struct inode *inode = file_inode(file); struct fuse_conn *fc = get_fuse_conn(inode); if (!fuse_allow_current_process(fc)) return -EACCES; if (is_bad_inode(inode)) return -EIO; return fuse_do_ioctl(file, cmd, arg, flags); } static long fuse_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { return fuse_ioctl_common(file, cmd, arg, 0); } static long fuse_file_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT); } /* * All files which have been polled are linked to RB tree * fuse_conn->polled_files which is indexed by kh. Walk the tree and * find the matching one. */ static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh, struct rb_node **parent_out) { struct rb_node **link = &fc->polled_files.rb_node; struct rb_node *last = NULL; while (*link) { struct fuse_file *ff; last = *link; ff = rb_entry(last, struct fuse_file, polled_node); if (kh < ff->kh) link = &last->rb_left; else if (kh > ff->kh) link = &last->rb_right; else return link; } if (parent_out) *parent_out = last; return link; } /* * The file is about to be polled. Make sure it's on the polled_files * RB tree. Note that files once added to the polled_files tree are * not removed before the file is released. This is because a file * polled once is likely to be polled again. */ static void fuse_register_polled_file(struct fuse_conn *fc, struct fuse_file *ff) { spin_lock(&fc->lock); if (RB_EMPTY_NODE(&ff->polled_node)) { struct rb_node **link, *uninitialized_var(parent); link = fuse_find_polled_node(fc, ff->kh, &parent); BUG_ON(*link); rb_link_node(&ff->polled_node, parent, link); rb_insert_color(&ff->polled_node, &fc->polled_files); } spin_unlock(&fc->lock); } __poll_t fuse_file_poll(struct file *file, poll_table *wait) { struct fuse_file *ff = file->private_data; struct fuse_conn *fc = ff->fc; struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh }; struct fuse_poll_out outarg; FUSE_ARGS(args); int err; if (fc->no_poll) return DEFAULT_POLLMASK; poll_wait(file, &ff->poll_wait, wait); inarg.events = mangle_poll(poll_requested_events(wait)); /* * Ask for notification iff there's someone waiting for it. * The client may ignore the flag and always notify. */ if (waitqueue_active(&ff->poll_wait)) { inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY; fuse_register_polled_file(fc, ff); } args.in.h.opcode = FUSE_POLL; args.in.h.nodeid = ff->nodeid; args.in.numargs = 1; args.in.args[0].size = sizeof(inarg); args.in.args[0].value = &inarg; 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) return demangle_poll(outarg.revents); if (err == -ENOSYS) { fc->no_poll = 1; return DEFAULT_POLLMASK; } return EPOLLERR; } EXPORT_SYMBOL_GPL(fuse_file_poll); /* * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and * wakes up the poll waiters. */ int fuse_notify_poll_wakeup(struct fuse_conn *fc, struct fuse_notify_poll_wakeup_out *outarg) { u64 kh = outarg->kh; struct rb_node **link; spin_lock(&fc->lock); link = fuse_find_polled_node(fc, kh, NULL); if (*link) { struct fuse_file *ff; ff = rb_entry(*link, struct fuse_file, polled_node); wake_up_interruptible_sync(&ff->poll_wait); } spin_unlock(&fc->lock); return 0; } static void fuse_do_truncate(struct file *file) { struct inode *inode = file->f_mapping->host; struct iattr attr; attr.ia_valid = ATTR_SIZE; attr.ia_size = i_size_read(inode); attr.ia_file = file; attr.ia_valid |= ATTR_FILE; fuse_do_setattr(file_dentry(file), &attr, file); } static inline loff_t fuse_round_up(struct fuse_conn *fc, loff_t off) { return round_up(off, fc->max_pages << PAGE_SHIFT); } static ssize_t fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter) { DECLARE_COMPLETION_ONSTACK(wait); ssize_t ret = 0; struct file *file = iocb->ki_filp; struct fuse_file *ff = file->private_data; bool async_dio = ff->fc->async_dio; loff_t pos = 0; struct inode *inode; loff_t i_size; size_t count = iov_iter_count(iter); loff_t offset = iocb->ki_pos; struct fuse_io_priv *io; pos = offset; inode = file->f_mapping->host; i_size = i_size_read(inode); if ((iov_iter_rw(iter) == READ) && (offset > i_size)) return 0; /* optimization for short read */ if (async_dio && iov_iter_rw(iter) != WRITE && offset + count > i_size) { if (offset >= i_size) return 0; iov_iter_truncate(iter, fuse_round_up(ff->fc, i_size - offset)); count = iov_iter_count(iter); } io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL); if (!io) return -ENOMEM; spin_lock_init(&io->lock); kref_init(&io->refcnt); io->reqs = 1; io->bytes = -1; io->size = 0; io->offset = offset; io->write = (iov_iter_rw(iter) == WRITE); io->err = 0; /* * By default, we want to optimize all I/Os with async request * submission to the client filesystem if supported. */ io->async = async_dio; io->iocb = iocb; io->blocking = is_sync_kiocb(iocb); /* * We cannot asynchronously extend the size of a file. * In such case the aio will behave exactly like sync io. */ if ((offset + count > i_size) && iov_iter_rw(iter) == WRITE) io->blocking = true; if (io->async && io->blocking) { /* * Additional reference to keep io around after * calling fuse_aio_complete() */ kref_get(&io->refcnt); io->done = &wait; } if (iov_iter_rw(iter) == WRITE) { ret = fuse_direct_io(io, iter, &pos, FUSE_DIO_WRITE); fuse_invalidate_attr(inode); } else { ret = __fuse_direct_read(io, iter, &pos); } if (io->async) { bool blocking = io->blocking; fuse_aio_complete(io, ret < 0 ? ret : 0, -1); /* we have a non-extending, async request, so return */ if (!blocking) return -EIOCBQUEUED; wait_for_completion(&wait); ret = fuse_get_res_by_io(io); } kref_put(&io->refcnt, fuse_io_release); if (iov_iter_rw(iter) == WRITE) { if (ret > 0) fuse_write_update_size(inode, pos); else if (ret < 0 && offset + count > i_size) fuse_do_truncate(file); } return ret; } static long fuse_file_fallocate(struct file *file, int mode, loff_t offset, loff_t length) { struct fuse_file *ff = file->private_data; struct inode *inode = file_inode(file); struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_conn *fc = ff->fc; FUSE_ARGS(args); struct fuse_fallocate_in inarg = { .fh = ff->fh, .offset = offset, .length = length, .mode = mode }; int err; bool lock_inode = !(mode & FALLOC_FL_KEEP_SIZE) || (mode & FALLOC_FL_PUNCH_HOLE); if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) return -EOPNOTSUPP; if (fc->no_fallocate) return -EOPNOTSUPP; if (lock_inode) { inode_lock(inode); if (mode & FALLOC_FL_PUNCH_HOLE) { loff_t endbyte = offset + length - 1; err = filemap_write_and_wait_range(inode->i_mapping, offset, endbyte); if (err) goto out; fuse_sync_writes(inode); } } if (!(mode & FALLOC_FL_KEEP_SIZE)) set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); args.in.h.opcode = FUSE_FALLOCATE; args.in.h.nodeid = ff->nodeid; args.in.numargs = 1; args.in.args[0].size = sizeof(inarg); args.in.args[0].value = &inarg; err = fuse_simple_request(fc, &args); if (err == -ENOSYS) { fc->no_fallocate = 1; err = -EOPNOTSUPP; } if (err) goto out; /* we could have extended the file */ if (!(mode & FALLOC_FL_KEEP_SIZE)) { bool changed = fuse_write_update_size(inode, offset + length); if (changed && fc->writeback_cache) file_update_time(file); } if (mode & FALLOC_FL_PUNCH_HOLE) truncate_pagecache_range(inode, offset, offset + length - 1); fuse_invalidate_attr(inode); out: if (!(mode & FALLOC_FL_KEEP_SIZE)) clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); if (lock_inode) inode_unlock(inode); return err; } static ssize_t fuse_copy_file_range(struct file *file_in, loff_t pos_in, struct file *file_out, loff_t pos_out, size_t len, unsigned int flags) { struct fuse_file *ff_in = file_in->private_data; struct fuse_file *ff_out = file_out->private_data; struct inode *inode_out = file_inode(file_out); struct fuse_inode *fi_out = get_fuse_inode(inode_out); struct fuse_conn *fc = ff_in->fc; FUSE_ARGS(args); struct fuse_copy_file_range_in inarg = { .fh_in = ff_in->fh, .off_in = pos_in, .nodeid_out = ff_out->nodeid, .fh_out = ff_out->fh, .off_out = pos_out, .len = len, .flags = flags }; struct fuse_write_out outarg; ssize_t err; /* mark unstable when write-back is not used, and file_out gets * extended */ bool is_unstable = (!fc->writeback_cache) && ((pos_out + len) > inode_out->i_size); if (fc->no_copy_file_range) return -EOPNOTSUPP; inode_lock(inode_out); if (fc->writeback_cache) { err = filemap_write_and_wait_range(inode_out->i_mapping, pos_out, pos_out + len); if (err) goto out; fuse_sync_writes(inode_out); } if (is_unstable) set_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state); args.in.h.opcode = FUSE_COPY_FILE_RANGE; args.in.h.nodeid = ff_in->nodeid; args.in.numargs = 1; args.in.args[0].size = sizeof(inarg); args.in.args[0].value = &inarg; 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 == -ENOSYS) { fc->no_copy_file_range = 1; err = -EOPNOTSUPP; } if (err) goto out; if (fc->writeback_cache) { fuse_write_update_size(inode_out, pos_out + outarg.size); file_update_time(file_out); } fuse_invalidate_attr(inode_out); err = outarg.size; out: if (is_unstable) clear_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state); inode_unlock(inode_out); return err; } static const struct file_operations fuse_file_operations = { .llseek = fuse_file_llseek, .read_iter = fuse_file_read_iter, .write_iter = fuse_file_write_iter, .mmap = fuse_file_mmap, .open = fuse_open, .flush = fuse_flush, .release = fuse_release, .fsync = fuse_fsync, .lock = fuse_file_lock, .flock = fuse_file_flock, .splice_read = generic_file_splice_read, .splice_write = iter_file_splice_write, .unlocked_ioctl = fuse_file_ioctl, .compat_ioctl = fuse_file_compat_ioctl, .poll = fuse_file_poll, .fallocate = fuse_file_fallocate, .copy_file_range = fuse_copy_file_range, }; static const struct file_operations fuse_direct_io_file_operations = { .llseek = fuse_file_llseek, .read_iter = fuse_direct_read_iter, .write_iter = fuse_direct_write_iter, .mmap = fuse_direct_mmap, .open = fuse_open, .flush = fuse_flush, .release = fuse_release, .fsync = fuse_fsync, .lock = fuse_file_lock, .flock = fuse_file_flock, .splice_read = generic_file_splice_read, .splice_write = iter_file_splice_write, .unlocked_ioctl = fuse_file_ioctl, .compat_ioctl = fuse_file_compat_ioctl, .poll = fuse_file_poll, .fallocate = fuse_file_fallocate, }; static const struct address_space_operations fuse_file_aops = { .readpage = fuse_readpage, .writepage = fuse_writepage, .writepages = fuse_writepages, .launder_page = fuse_launder_page, .readpages = fuse_readpages, .set_page_dirty = __set_page_dirty_nobuffers, .bmap = fuse_bmap, .direct_IO = fuse_direct_IO, .write_begin = fuse_write_begin, .write_end = fuse_write_end, }; void fuse_init_file_inode(struct inode *inode) { struct fuse_inode *fi = get_fuse_inode(inode); inode->i_fop = &fuse_file_operations; inode->i_data.a_ops = &fuse_file_aops; INIT_LIST_HEAD(&fi->write_files); INIT_LIST_HEAD(&fi->queued_writes); fi->writectr = 0; init_waitqueue_head(&fi->page_waitq); INIT_LIST_HEAD(&fi->writepages); }