// SPDX-License-Identifier: GPL-2.0-or-later/* handling of writes to regular files and writing back to the server * * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) */ #include <linux/backing-dev.h>#include <linux/slab.h>#include <linux/fs.h>#include <linux/pagemap.h>#include <linux/writeback.h>#include <linux/netfs.h>#include <trace/events/netfs.h>#include "internal.h" /* * completion of write to server */static void afs_pages_written_back(struct afs_vnode *vnode, loff_t start, unsigned int len){	_enter("{%llx:%llu},{%x @%llx}",	       vnode->fid.vid, vnode->fid.vnode, len, start); 	afs_prune_wb_keys(vnode);	_leave("");} /* * Find a key to use for the writeback.  We cached the keys used to author the * writes on the vnode.  wreq->netfs_priv2 will contain the last writeback key * record used or NULL and we need to start from there if it's set. * wreq->netfs_priv will be set to the key itself or NULL. */static void afs_get_writeback_key(struct netfs_io_request *wreq){	struct afs_wb_key *wbk, *old = wreq->netfs_priv2;	struct afs_vnode *vnode = AFS_FS_I(wreq->inode); 	key_put(wreq->netfs_priv);	wreq->netfs_priv = NULL;	wreq->netfs_priv2 = NULL; 	spin_lock(&vnode->wb_lock);	if (old)		wbk = list_next_entry(old, vnode_link);	else		wbk = list_first_entry(&vnode->wb_keys, struct afs_wb_key, vnode_link); 	list_for_each_entry_from(wbk, &vnode->wb_keys, vnode_link) {		_debug("wbk %u", key_serial(wbk->key));		if (key_validate(wbk->key) == 0) {			refcount_inc(&wbk->usage);			wreq->netfs_priv = key_get(wbk->key);			wreq->netfs_priv2 = wbk;			_debug("USE WB KEY %u", key_serial(wbk->key));			break;		}	} 	spin_unlock(&vnode->wb_lock); 	afs_put_wb_key(old);} static void afs_store_data_success(struct afs_operation *op){	struct afs_vnode *vnode = op->file[0].vnode; 	op->ctime = op->file[0].scb.status.mtime_client;	afs_vnode_commit_status(op, &op->file[0]);	if (!afs_op_error(op)) {		afs_pages_written_back(vnode, op->store.pos, op->store.size);		afs_stat_v(vnode, n_stores);		atomic_long_add(op->store.size, &afs_v2net(vnode)->n_store_bytes);	}} static const struct afs_operation_ops afs_store_data_operation = {	.issue_afs_rpc	= afs_fs_store_data,	.issue_yfs_rpc	= yfs_fs_store_data,	.success	= afs_store_data_success,}; /* * Prepare a subrequest to write to the server.  This sets the max_len * parameter. */void afs_prepare_write(struct netfs_io_subrequest *subreq){	struct netfs_io_stream *stream = &subreq->rreq->io_streams[subreq->stream_nr]; 	//if (test_bit(NETFS_SREQ_RETRYING, &subreq->flags))	//	subreq->max_len = 512 * 1024;	//else	stream->sreq_max_len = 256 * 1024 * 1024;} /* * Issue a subrequest to write to the server. */static void afs_issue_write_worker(struct work_struct *work){	struct netfs_io_subrequest *subreq = container_of(work, struct netfs_io_subrequest, work);	struct netfs_io_request *wreq = subreq->rreq;	struct afs_operation *op;	struct afs_vnode *vnode = AFS_FS_I(wreq->inode);	unsigned long long pos = subreq->start + subreq->transferred;	size_t len = subreq->len - subreq->transferred;	int ret = -ENOKEY; 	_enter("R=%x[%x],%s{%llx:%llu.%u},%llx,%zx",	       wreq->debug_id, subreq->debug_index,	       vnode->volume->name,	       vnode->fid.vid,	       vnode->fid.vnode,	       vnode->fid.unique,	       pos, len); #if 0 // Error injection	if (subreq->debug_index == 3)		return netfs_write_subrequest_terminated(subreq, -ENOANO); 	if (!subreq->retry_count) {		set_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);		return netfs_write_subrequest_terminated(subreq, -EAGAIN);	}#endif 	op = afs_alloc_operation(wreq->netfs_priv, vnode->volume);	if (IS_ERR(op))		return netfs_write_subrequest_terminated(subreq, -EAGAIN); 	afs_op_set_vnode(op, 0, vnode);	op->file[0].dv_delta	= 1;	op->file[0].modification = true;	op->store.pos		= pos;	op->store.size		= len;	op->flags		|= AFS_OPERATION_UNINTR;	op->ops			= &afs_store_data_operation; 	afs_begin_vnode_operation(op); 	op->store.write_iter	= &subreq->io_iter;	op->store.i_size	= umax(pos + len, netfs_read_remote_i_size(&vnode->netfs.inode));	op->mtime		= inode_get_mtime(&vnode->netfs.inode); 	afs_wait_for_operation(op);	ret = afs_put_operation(op);	switch (ret) {	case 0:		__set_bit(NETFS_SREQ_MADE_PROGRESS, &subreq->flags);		break;	case -EACCES:	case -EPERM:	case -ENOKEY:	case -EKEYEXPIRED:	case -EKEYREJECTED:	case -EKEYREVOKED:		/* If there are more keys we can try, use the retry algorithm		 * to rotate the keys.		 */		if (wreq->netfs_priv2)			set_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);		break;	} 	netfs_write_subrequest_terminated(subreq, ret < 0 ? ret : subreq->len);} void afs_issue_write(struct netfs_io_subrequest *subreq){	subreq->work.func = afs_issue_write_worker;	if (!queue_work(system_dfl_wq, &subreq->work))		WARN_ON_ONCE(1);} /* * Writeback calls this when it finds a folio that needs uploading.  This isn't * called if writeback only has copy-to-cache to deal with. */void afs_begin_writeback(struct netfs_io_request *wreq){	if (S_ISREG(wreq->inode->i_mode))		afs_get_writeback_key(wreq);} /* * Prepare to retry the writes in request.  Use this to try rotating the * available writeback keys. */void afs_retry_request(struct netfs_io_request *wreq, struct netfs_io_stream *stream){	struct netfs_io_subrequest *subreq =		list_first_entry(&stream->subrequests,				 struct netfs_io_subrequest, rreq_link); 	switch (wreq->origin) {	case NETFS_READAHEAD:	case NETFS_READPAGE:	case NETFS_READ_GAPS:	case NETFS_READ_SINGLE:	case NETFS_READ_FOR_WRITE:	case NETFS_UNBUFFERED_READ:	case NETFS_DIO_READ:		return;	default:		break;	} 	switch (subreq->error) {	case -EACCES:	case -EPERM:	case -ENOKEY:	case -EKEYEXPIRED:	case -EKEYREJECTED:	case -EKEYREVOKED:		afs_get_writeback_key(wreq);		if (!wreq->netfs_priv)			stream->failed = true;		break;	}} /* * write some of the pending data back to the server */int afs_writepages(struct address_space *mapping, struct writeback_control *wbc){	struct afs_vnode *vnode = AFS_FS_I(mapping->host);	int ret; 	/* We have to be careful as we can end up racing with setattr()	 * truncating the pagecache since the caller doesn't take a lock here	 * to prevent it.	 */	if (wbc->sync_mode == WB_SYNC_ALL)		down_read(&vnode->validate_lock);	else if (!down_read_trylock(&vnode->validate_lock))		return 0; 	ret = netfs_writepages(mapping, wbc);	up_read(&vnode->validate_lock);	return ret;} /* * flush any dirty pages for this process, and check for write errors. * - the return status from this call provides a reliable indication of *   whether any write errors occurred for this process. */int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync){	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));	struct afs_file *af = file->private_data;	int ret; 	_enter("{%llx:%llu},{n=%pD},%d",	       vnode->fid.vid, vnode->fid.vnode, file,	       datasync); 	ret = afs_validate(vnode, af->key);	if (ret < 0)		return ret; 	return file_write_and_wait_range(file, start, end);} /* * notification that a previously read-only page is about to become writable * - if it returns an error, the caller will deliver a bus error signal */vm_fault_t afs_page_mkwrite(struct vm_fault *vmf){	struct file *file = vmf->vma->vm_file; 	if (afs_validate(AFS_FS_I(file_inode(file)), afs_file_key(file)) < 0)		return VM_FAULT_SIGBUS;	return netfs_page_mkwrite(vmf, NULL);} /* * Prune the keys cached for writeback.  The caller must hold vnode->wb_lock. */void afs_prune_wb_keys(struct afs_vnode *vnode){	LIST_HEAD(graveyard);	struct afs_wb_key *wbk, *tmp; 	/* Discard unused keys */	spin_lock(&vnode->wb_lock); 	if (!mapping_tagged(&vnode->netfs.inode.i_data, PAGECACHE_TAG_WRITEBACK) &&	    !mapping_tagged(&vnode->netfs.inode.i_data, PAGECACHE_TAG_DIRTY)) {		list_for_each_entry_safe(wbk, tmp, &vnode->wb_keys, vnode_link) {			if (refcount_read(&wbk->usage) == 1)				list_move(&wbk->vnode_link, &graveyard);		}	} 	spin_unlock(&vnode->wb_lock); 	while (!list_empty(&graveyard)) {		wbk = list_entry(graveyard.next, struct afs_wb_key, vnode_link);		list_del(&wbk->vnode_link);		afs_put_wb_key(wbk);	}}