1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Network filesystem high-level buffered read support.
21 	pgoff_t start_page = rreq->start / PAGE_SIZE;  in netfs_rreq_unlock_folios()
22 	pgoff_t last_page = ((rreq->start + rreq->len) / PAGE_SIZE) - 1;  in netfs_rreq_unlock_folios()
26 	XA_STATE(xas, &rreq->mapping->i_pages, start_page);  in netfs_rreq_unlock_folios()
28 	if (test_bit(NETFS_RREQ_FAILED, &rreq->flags)) {  in netfs_rreq_unlock_folios()
29 		__clear_bit(NETFS_RREQ_COPY_TO_CACHE, &rreq->flags);  in netfs_rreq_unlock_folios()
30 		list_for_each_entry(subreq, &rreq->subrequests, rreq_link) {  in netfs_rreq_unlock_folios()
31 			__clear_bit(NETFS_SREQ_COPY_TO_CACHE, &subreq->flags);  in netfs_rreq_unlock_folios()
41 	subreq = list_first_entry(&rreq->subrequests,  in netfs_rreq_unlock_folios()
43 	subreq_failed = (subreq->error < 0);  in netfs_rreq_unlock_folios()
56 		pg_end = folio_pos(folio) + folio_size(folio) - 1;  in netfs_rreq_unlock_folios()
66 			if (!folio_started && test_bit(NETFS_SREQ_COPY_TO_CACHE, &subreq->flags)) {  in netfs_rreq_unlock_folios()
72 			sreq_end = subreq->start + subreq->len - 1;  in netfs_rreq_unlock_folios()
76 			account += subreq->transferred;  in netfs_rreq_unlock_folios()
77 			if (!list_is_last(&subreq->rreq_link, &rreq->subrequests)) {  in netfs_rreq_unlock_folios()
79 				subreq_failed = (subreq->error < 0);  in netfs_rreq_unlock_folios()
94 				if (finfo->netfs_group)  in netfs_rreq_unlock_folios()
95 					folio_change_private(folio, finfo->netfs_group);  in netfs_rreq_unlock_folios()
103 		if (!test_bit(NETFS_RREQ_DONT_UNLOCK_FOLIOS, &rreq->flags)) {  in netfs_rreq_unlock_folios()
104 			if (folio->index == rreq->no_unlock_folio &&  in netfs_rreq_unlock_folios()
105 			    test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags))  in netfs_rreq_unlock_folios()
114 	if (rreq->netfs_ops->done)  in netfs_rreq_unlock_folios()
115 		rreq->netfs_ops->done(rreq);  in netfs_rreq_unlock_folios()
121 	struct netfs_cache_resources *cres = &rreq->cache_resources;  in netfs_cache_expand_readahead()
123 	if (cres->ops && cres->ops->expand_readahead)  in netfs_cache_expand_readahead()
124 		cres->ops->expand_readahead(cres, _start, _len, i_size);  in netfs_cache_expand_readahead()
133 	netfs_cache_expand_readahead(rreq, &rreq->start, &rreq->len, rreq->i_size);  in netfs_rreq_expand()
138 	if (rreq->netfs_ops->expand_readahead)  in netfs_rreq_expand()
139 		rreq->netfs_ops->expand_readahead(rreq);  in netfs_rreq_expand()
150 	if (rreq->start  != readahead_pos(ractl) ||  in netfs_rreq_expand()
151 	    rreq->len != readahead_length(ractl)) {  in netfs_rreq_expand()
152 		readahead_expand(ractl, rreq->start, rreq->len);  in netfs_rreq_expand()
153 		rreq->start  = readahead_pos(ractl);  in netfs_rreq_expand()
154 		rreq->len = readahead_length(ractl);  in netfs_rreq_expand()
167 	return fscache_begin_read_operation(&rreq->cache_resources, netfs_i_cookie(ctx));  in netfs_begin_cache_read()
171  * netfs_readahead - Helper to manage a read request
174  * Fulfil a readahead request by drawing data from the cache if possible, or
175  * the netfs if not.  Space beyond the EOF is zero-filled.  Multiple I/O
188 	struct netfs_inode *ctx = netfs_inode(ractl->mapping->host);  in netfs_readahead()
196 	rreq = netfs_alloc_request(ractl->mapping, ractl->file,  in netfs_readahead()
204 	if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)  in netfs_readahead()
214 	iov_iter_xarray(&rreq->iter, ITER_DEST, &ractl->mapping->i_pages,  in netfs_readahead()
215 			rreq->start, rreq->len);  in netfs_readahead()
234  * netfs_read_folio - Helper to manage a read_folio request
238  * Fulfil a read_folio request by drawing data from the cache if
239  * possible, or the netfs if not.  Space beyond the EOF is zero-filled.
249 	struct address_space *mapping = folio->mapping;  in netfs_read_folio()  local
251 	struct netfs_inode *ctx = netfs_inode(mapping->host);  in netfs_read_folio()
255 	_enter("%lx", folio->index);  in netfs_read_folio()
257 	rreq = netfs_alloc_request(mapping, file,  in netfs_read_folio()
266 	if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)  in netfs_read_folio()
270 	trace_netfs_read(rreq, rreq->start, rreq->len, netfs_read_trace_readpage);  in netfs_read_folio()
281 		unsigned int from = finfo->dirty_offset;  in netfs_read_folio()
282 		unsigned int to = from + finfo->dirty_len;  in netfs_read_folio()
288 		ret = -ENOMEM;  in netfs_read_folio()
299 		rreq->direct_bv = bvec;  in netfs_read_folio()
300 		rreq->direct_bv_count = nr_bvec;  in netfs_read_folio()
306 			part = min_t(size_t, to - off, PAGE_SIZE);  in netfs_read_folio()
311 			bvec_set_folio(&bvec[i++], folio, flen - to, to);  in netfs_read_folio()
312 		iov_iter_bvec(&rreq->iter, ITER_DEST, bvec, i, rreq->len);  in netfs_read_folio()
314 		iov_iter_xarray(&rreq->iter, ITER_DEST, &mapping->i_pages,  in netfs_read_folio()
315 				rreq->start, rreq->len);  in netfs_read_folio()
340  * - full folio write
341  * - write that lies in a folio that is completely beyond EOF
342  * - write that covers the folio from start to EOF or beyond it
356 		if (pos - offset + len <= i_size)  in netfs_skip_folio_read()
358 		zero_user_segment(&folio->page, 0, plen);  in netfs_skip_folio_read()
368 	if (pos - offset >= i_size)  in netfs_skip_folio_read()
377 	zero_user_segments(&folio->page, 0, offset, offset + len, plen);  in netfs_skip_folio_read()
382  * netfs_write_begin - Helper to prepare for writing
385  * @mapping: The mapping to read from
391  * Pre-read data for a write-begin request by drawing data from the cache if
392  * possible, or the netfs if not.  Space beyond the EOF is zero-filled.
407  * will cause the folio to be re-got and the process to be retried.
415 		      struct file *file, struct address_space *mapping,  in netfs_write_begin()  argument
424 	DEFINE_READAHEAD(ractl, file, NULL, mapping, index);  in netfs_write_begin()
427 	folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,  in netfs_write_begin()
428 				    mapping_gfp_mask(mapping));  in netfs_write_begin()
432 	if (ctx->ops->check_write_begin) {  in netfs_write_begin()
434 		ret = ctx->ops->check_write_begin(file, pos, len, &folio, _fsdata);  in netfs_write_begin()
446 	/* If the page is beyond the EOF, we want to clear it - unless it's  in netfs_write_begin()
456 	rreq = netfs_alloc_request(mapping, file,  in netfs_write_begin()
463 	rreq->no_unlock_folio	= folio->index;  in netfs_write_begin()
464 	__set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags);  in netfs_write_begin()
467 	if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)  in netfs_write_begin()
480 	iov_iter_xarray(&rreq->iter, ITER_DEST, &mapping->i_pages,  in netfs_write_begin()
481 			rreq->start, rreq->len);  in netfs_write_begin()
515  * Preload the data into a page we're proposing to write into.
521 	struct address_space *mapping = folio->mapping;  in netfs_prefetch_for_write()  local
522 	struct netfs_inode *ctx = netfs_inode(mapping->host);  in netfs_prefetch_for_write()
529 	ret = -ENOMEM;  in netfs_prefetch_for_write()
531 	rreq = netfs_alloc_request(mapping, file, start, flen,  in netfs_prefetch_for_write()
538 	rreq->no_unlock_folio = folio->index;  in netfs_prefetch_for_write()
539 	__set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags);  in netfs_prefetch_for_write()
541 	if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)  in netfs_prefetch_for_write()
548 	iov_iter_xarray(&rreq->iter, ITER_DEST, &mapping->i_pages,  in netfs_prefetch_for_write()
549 			rreq->start, rreq->len);  in netfs_prefetch_for_write()
563  * netfs_buffered_read_iter - Filesystem buffered I/O read routine
565  * @iter: destination for the data read
567  * This is the ->read_iter() routine for all filesystems that can use the page
570  * The IOCB_NOWAIT flag in iocb->ki_flags indicates that -EAGAIN shall be
571  * returned when no data can be read without waiting for I/O requests to
574  * The IOCB_NOIO flag in iocb->ki_flags indicates that no new I/O requests
575  * shall be made for the read or for readahead.  When no data can be read,
576  * -EAGAIN shall be returned.  When readahead would be triggered, a partial,
585 	struct inode *inode = file_inode(iocb->ki_filp);  in netfs_buffered_read_iter()
589 	if (WARN_ON_ONCE((iocb->ki_flags & IOCB_DIRECT) ||  in netfs_buffered_read_iter()
590 			 test_bit(NETFS_ICTX_UNBUFFERED, &ictx->flags)))  in netfs_buffered_read_iter()
591 		return -EINVAL;  in netfs_buffered_read_iter()
603  * netfs_file_read_iter - Generic filesystem read routine
605  * @iter: destination for the data read
607  * This is the ->read_iter() routine for all filesystems that can use the page
610  * The IOCB_NOWAIT flag in iocb->ki_flags indicates that -EAGAIN shall be
611  * returned when no data can be read without waiting for I/O requests to
614  * The IOCB_NOIO flag in iocb->ki_flags indicates that no new I/O requests
615  * shall be made for the read or for readahead.  When no data can be read,
616  * -EAGAIN shall be returned.  When readahead would be triggered, a partial,
625 	struct netfs_inode *ictx = netfs_inode(iocb->ki_filp->f_mapping->host);  in netfs_file_read_iter()
627 	if ((iocb->ki_flags & IOCB_DIRECT) ||  in netfs_file_read_iter()
628 	    test_bit(NETFS_ICTX_UNBUFFERED, &ictx->flags))  in netfs_file_read_iter()