| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* Unbuffered and direct write support. |
| * |
| * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved. |
| * Written by David Howells (dhowells@redhat.com) |
| */ |
| |
| #include <linux/export.h> |
| #include <linux/uio.h> |
| #include "internal.h" |
| |
| static void netfs_cleanup_dio_write(struct netfs_io_request *wreq) |
| { |
| struct inode *inode = wreq->inode; |
| unsigned long long end = wreq->start + wreq->transferred; |
| |
| if (!wreq->error && |
| i_size_read(inode) < end) { |
| if (wreq->netfs_ops->update_i_size) |
| wreq->netfs_ops->update_i_size(inode, end); |
| else |
| i_size_write(inode, end); |
| } |
| } |
| |
| /* |
| * Perform an unbuffered write where we may have to do an RMW operation on an |
| * encrypted file. This can also be used for direct I/O writes. |
| */ |
| ssize_t netfs_unbuffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *iter, |
| struct netfs_group *netfs_group) |
| { |
| struct netfs_io_request *wreq; |
| unsigned long long start = iocb->ki_pos; |
| unsigned long long end = start + iov_iter_count(iter); |
| ssize_t ret, n; |
| size_t len = iov_iter_count(iter); |
| bool async = !is_sync_kiocb(iocb); |
| |
| _enter(""); |
| |
| /* We're going to need a bounce buffer if what we transmit is going to |
| * be different in some way to the source buffer, e.g. because it gets |
| * encrypted/compressed or because it needs expanding to a block size. |
| */ |
| // TODO |
| |
| _debug("uw %llx-%llx", start, end); |
| |
| wreq = netfs_create_write_req(iocb->ki_filp->f_mapping, iocb->ki_filp, start, |
| iocb->ki_flags & IOCB_DIRECT ? |
| NETFS_DIO_WRITE : NETFS_UNBUFFERED_WRITE); |
| if (IS_ERR(wreq)) |
| return PTR_ERR(wreq); |
| |
| wreq->io_streams[0].avail = true; |
| trace_netfs_write(wreq, (iocb->ki_flags & IOCB_DIRECT ? |
| netfs_write_trace_dio_write : |
| netfs_write_trace_unbuffered_write)); |
| |
| { |
| /* If this is an async op and we're not using a bounce buffer, |
| * we have to save the source buffer as the iterator is only |
| * good until we return. In such a case, extract an iterator |
| * to represent as much of the the output buffer as we can |
| * manage. Note that the extraction might not be able to |
| * allocate a sufficiently large bvec array and may shorten the |
| * request. |
| */ |
| if (async || user_backed_iter(iter)) { |
| n = netfs_extract_user_iter(iter, len, &wreq->iter, 0); |
| if (n < 0) { |
| ret = n; |
| goto out; |
| } |
| wreq->direct_bv = (struct bio_vec *)wreq->iter.bvec; |
| wreq->direct_bv_count = n; |
| wreq->direct_bv_unpin = iov_iter_extract_will_pin(iter); |
| } else { |
| wreq->iter = *iter; |
| } |
| |
| wreq->io_iter = wreq->iter; |
| } |
| |
| __set_bit(NETFS_RREQ_USE_IO_ITER, &wreq->flags); |
| |
| /* Copy the data into the bounce buffer and encrypt it. */ |
| // TODO |
| |
| /* Dispatch the write. */ |
| __set_bit(NETFS_RREQ_UPLOAD_TO_SERVER, &wreq->flags); |
| if (async) |
| wreq->iocb = iocb; |
| wreq->cleanup = netfs_cleanup_dio_write; |
| ret = netfs_unbuffered_write(wreq, is_sync_kiocb(iocb), iov_iter_count(&wreq->io_iter)); |
| if (ret < 0) { |
| _debug("begin = %zd", ret); |
| goto out; |
| } |
| |
| if (!async) { |
| trace_netfs_rreq(wreq, netfs_rreq_trace_wait_ip); |
| wait_on_bit(&wreq->flags, NETFS_RREQ_IN_PROGRESS, |
| TASK_UNINTERRUPTIBLE); |
| smp_rmb(); /* Read error/transferred after RIP flag */ |
| ret = wreq->error; |
| if (ret == 0) { |
| ret = wreq->transferred; |
| iocb->ki_pos += ret; |
| } |
| } else { |
| ret = -EIOCBQUEUED; |
| } |
| |
| out: |
| netfs_put_request(wreq, false, netfs_rreq_trace_put_return); |
| return ret; |
| } |
| EXPORT_SYMBOL(netfs_unbuffered_write_iter_locked); |
| |
| /** |
| * netfs_unbuffered_write_iter - Unbuffered write to a file |
| * @iocb: IO state structure |
| * @from: iov_iter with data to write |
| * |
| * Do an unbuffered write to a file, writing the data directly to the server |
| * and not lodging the data in the pagecache. |
| * |
| * Return: |
| * * Negative error code if no data has been written at all of |
| * vfs_fsync_range() failed for a synchronous write |
| * * Number of bytes written, even for truncated writes |
| */ |
| ssize_t netfs_unbuffered_write_iter(struct kiocb *iocb, struct iov_iter *from) |
| { |
| struct file *file = iocb->ki_filp; |
| struct address_space *mapping = file->f_mapping; |
| struct inode *inode = mapping->host; |
| struct netfs_inode *ictx = netfs_inode(inode); |
| ssize_t ret; |
| loff_t pos = iocb->ki_pos; |
| unsigned long long end = pos + iov_iter_count(from) - 1; |
| |
| _enter("%llx,%zx,%llx", pos, iov_iter_count(from), i_size_read(inode)); |
| |
| if (!iov_iter_count(from)) |
| return 0; |
| |
| trace_netfs_write_iter(iocb, from); |
| netfs_stat(&netfs_n_wh_dio_write); |
| |
| ret = netfs_start_io_direct(inode); |
| if (ret < 0) |
| return ret; |
| ret = generic_write_checks(iocb, from); |
| if (ret <= 0) |
| goto out; |
| ret = file_remove_privs(file); |
| if (ret < 0) |
| goto out; |
| ret = file_update_time(file); |
| if (ret < 0) |
| goto out; |
| if (iocb->ki_flags & IOCB_NOWAIT) { |
| /* We could block if there are any pages in the range. */ |
| ret = -EAGAIN; |
| if (filemap_range_has_page(mapping, pos, end)) |
| if (filemap_invalidate_inode(inode, true, pos, end)) |
| goto out; |
| } else { |
| ret = filemap_write_and_wait_range(mapping, pos, end); |
| if (ret < 0) |
| goto out; |
| } |
| |
| /* |
| * After a write we want buffered reads to be sure to go to disk to get |
| * the new data. We invalidate clean cached page from the region we're |
| * about to write. We do this *before* the write so that we can return |
| * without clobbering -EIOCBQUEUED from ->direct_IO(). |
| */ |
| ret = filemap_invalidate_inode(inode, true, pos, end); |
| if (ret < 0) |
| goto out; |
| end = iocb->ki_pos + iov_iter_count(from); |
| if (end > ictx->zero_point) |
| ictx->zero_point = end; |
| |
| fscache_invalidate(netfs_i_cookie(ictx), NULL, i_size_read(inode), |
| FSCACHE_INVAL_DIO_WRITE); |
| ret = netfs_unbuffered_write_iter_locked(iocb, from, NULL); |
| out: |
| netfs_end_io_direct(inode); |
| return ret; |
| } |
| EXPORT_SYMBOL(netfs_unbuffered_write_iter); |