1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Unbuffered and direct write support.
4 * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
8 #include <linux/export.h>
12 static void netfs_cleanup_dio_write(struct netfs_io_request *wreq)
14 struct inode *inode = wreq->inode;
15 unsigned long long end = wreq->start + wreq->len;
18 i_size_read(inode) < end) {
19 if (wreq->netfs_ops->update_i_size)
20 wreq->netfs_ops->update_i_size(inode, end);
22 i_size_write(inode, end);
27 * Perform an unbuffered write where we may have to do an RMW operation on an
28 * encrypted file. This can also be used for direct I/O writes.
30 static ssize_t netfs_unbuffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *iter,
31 struct netfs_group *netfs_group)
33 struct netfs_io_request *wreq;
34 unsigned long long start = iocb->ki_pos;
35 unsigned long long end = start + iov_iter_count(iter);
37 bool async = !is_sync_kiocb(iocb);
41 /* We're going to need a bounce buffer if what we transmit is going to
42 * be different in some way to the source buffer, e.g. because it gets
43 * encrypted/compressed or because it needs expanding to a block size.
47 _debug("uw %llx-%llx", start, end);
49 wreq = netfs_alloc_request(iocb->ki_filp->f_mapping, iocb->ki_filp,
51 iocb->ki_flags & IOCB_DIRECT ?
52 NETFS_DIO_WRITE : NETFS_UNBUFFERED_WRITE);
57 /* If this is an async op and we're not using a bounce buffer,
58 * we have to save the source buffer as the iterator is only
59 * good until we return. In such a case, extract an iterator
60 * to represent as much of the the output buffer as we can
61 * manage. Note that the extraction might not be able to
62 * allocate a sufficiently large bvec array and may shorten the
65 if (async || user_backed_iter(iter)) {
66 n = netfs_extract_user_iter(iter, wreq->len, &wreq->iter, 0);
71 wreq->direct_bv = (struct bio_vec *)wreq->iter.bvec;
72 wreq->direct_bv_count = n;
73 wreq->direct_bv_unpin = iov_iter_extract_will_pin(iter);
74 wreq->len = iov_iter_count(&wreq->iter);
79 wreq->io_iter = wreq->iter;
82 /* Copy the data into the bounce buffer and encrypt it. */
85 /* Dispatch the write. */
86 __set_bit(NETFS_RREQ_UPLOAD_TO_SERVER, &wreq->flags);
89 wreq->cleanup = netfs_cleanup_dio_write;
90 ret = netfs_begin_write(wreq, is_sync_kiocb(iocb),
91 iocb->ki_flags & IOCB_DIRECT ?
92 netfs_write_trace_dio_write :
93 netfs_write_trace_unbuffered_write);
95 _debug("begin = %zd", ret);
100 trace_netfs_rreq(wreq, netfs_rreq_trace_wait_ip);
101 wait_on_bit(&wreq->flags, NETFS_RREQ_IN_PROGRESS,
102 TASK_UNINTERRUPTIBLE);
105 _debug("waited = %zd", ret);
107 ret = wreq->transferred;
115 netfs_put_request(wreq, false, netfs_rreq_trace_put_return);
120 * netfs_unbuffered_write_iter - Unbuffered write to a file
121 * @iocb: IO state structure
122 * @from: iov_iter with data to write
124 * Do an unbuffered write to a file, writing the data directly to the server
125 * and not lodging the data in the pagecache.
128 * * Negative error code if no data has been written at all of
129 * vfs_fsync_range() failed for a synchronous write
130 * * Number of bytes written, even for truncated writes
132 ssize_t netfs_unbuffered_write_iter(struct kiocb *iocb, struct iov_iter *from)
134 struct file *file = iocb->ki_filp;
135 struct inode *inode = file->f_mapping->host;
136 struct netfs_inode *ictx = netfs_inode(inode);
137 unsigned long long end;
140 _enter("%llx,%zx,%llx", iocb->ki_pos, iov_iter_count(from), i_size_read(inode));
142 if (!iov_iter_count(from))
145 trace_netfs_write_iter(iocb, from);
146 netfs_stat(&netfs_n_rh_dio_write);
148 ret = netfs_start_io_direct(inode);
151 ret = generic_write_checks(iocb, from);
154 ret = file_remove_privs(file);
157 ret = file_update_time(file);
160 ret = kiocb_invalidate_pages(iocb, iov_iter_count(from));
163 end = iocb->ki_pos + iov_iter_count(from);
164 if (end > ictx->zero_point)
165 ictx->zero_point = end;
167 fscache_invalidate(netfs_i_cookie(ictx), NULL, i_size_read(inode),
168 FSCACHE_INVAL_DIO_WRITE);
169 ret = netfs_unbuffered_write_iter_locked(iocb, from, NULL);
171 netfs_end_io_direct(inode);
174 EXPORT_SYMBOL(netfs_unbuffered_write_iter);