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1// SPDX-License-Identifier: GPL-2.0-or-later2/* handling of writes to regular files and writing back to the server3 *4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.5 * Written by David Howells (dhowells@redhat.com)6 */7 8#include <linux/backing-dev.h>9#include <linux/slab.h>10#include <linux/fs.h>11#include <linux/pagemap.h>12#include <linux/writeback.h>13#include <linux/pagevec.h>14#include <linux/netfs.h>15#include <trace/events/netfs.h>16#include "internal.h"17 18/*19 * completion of write to server20 */21static void afs_pages_written_back(struct afs_vnode *vnode, loff_t start, unsigned int len)22{23 _enter("{%llx:%llu},{%x @%llx}",24 vnode->fid.vid, vnode->fid.vnode, len, start);25 26 afs_prune_wb_keys(vnode);27 _leave("");28}29 30/*31 * Find a key to use for the writeback. We cached the keys used to author the32 * writes on the vnode. wreq->netfs_priv2 will contain the last writeback key33 * record used or NULL and we need to start from there if it's set.34 * wreq->netfs_priv will be set to the key itself or NULL.35 */36static void afs_get_writeback_key(struct netfs_io_request *wreq)37{38 struct afs_wb_key *wbk, *old = wreq->netfs_priv2;39 struct afs_vnode *vnode = AFS_FS_I(wreq->inode);40 41 key_put(wreq->netfs_priv);42 wreq->netfs_priv = NULL;43 wreq->netfs_priv2 = NULL;44 45 spin_lock(&vnode->wb_lock);46 if (old)47 wbk = list_next_entry(old, vnode_link);48 else49 wbk = list_first_entry(&vnode->wb_keys, struct afs_wb_key, vnode_link);50 51 list_for_each_entry_from(wbk, &vnode->wb_keys, vnode_link) {52 _debug("wbk %u", key_serial(wbk->key));53 if (key_validate(wbk->key) == 0) {54 refcount_inc(&wbk->usage);55 wreq->netfs_priv = key_get(wbk->key);56 wreq->netfs_priv2 = wbk;57 _debug("USE WB KEY %u", key_serial(wbk->key));58 break;59 }60 }61 62 spin_unlock(&vnode->wb_lock);63 64 afs_put_wb_key(old);65}66 67static void afs_store_data_success(struct afs_operation *op)68{69 struct afs_vnode *vnode = op->file[0].vnode;70 71 op->ctime = op->file[0].scb.status.mtime_client;72 afs_vnode_commit_status(op, &op->file[0]);73 if (!afs_op_error(op)) {74 afs_pages_written_back(vnode, op->store.pos, op->store.size);75 afs_stat_v(vnode, n_stores);76 atomic_long_add(op->store.size, &afs_v2net(vnode)->n_store_bytes);77 }78}79 80static const struct afs_operation_ops afs_store_data_operation = {81 .issue_afs_rpc = afs_fs_store_data,82 .issue_yfs_rpc = yfs_fs_store_data,83 .success = afs_store_data_success,84};85 86/*87 * Prepare a subrequest to write to the server. This sets the max_len88 * parameter.89 */90void afs_prepare_write(struct netfs_io_subrequest *subreq)91{92 struct netfs_io_stream *stream = &subreq->rreq->io_streams[subreq->stream_nr];93 94 //if (test_bit(NETFS_SREQ_RETRYING, &subreq->flags))95 // subreq->max_len = 512 * 1024;96 //else97 stream->sreq_max_len = 256 * 1024 * 1024;98}99 100/*101 * Issue a subrequest to write to the server.102 */103static void afs_issue_write_worker(struct work_struct *work)104{105 struct netfs_io_subrequest *subreq = container_of(work, struct netfs_io_subrequest, work);106 struct netfs_io_request *wreq = subreq->rreq;107 struct afs_operation *op;108 struct afs_vnode *vnode = AFS_FS_I(wreq->inode);109 unsigned long long pos = subreq->start + subreq->transferred;110 size_t len = subreq->len - subreq->transferred;111 int ret = -ENOKEY;112 113 _enter("R=%x[%x],%s{%llx:%llu.%u},%llx,%zx",114 wreq->debug_id, subreq->debug_index,115 vnode->volume->name,116 vnode->fid.vid,117 vnode->fid.vnode,118 vnode->fid.unique,119 pos, len);120 121#if 0 // Error injection122 if (subreq->debug_index == 3)123 return netfs_write_subrequest_terminated(subreq, -ENOANO, false);124 125 if (!test_bit(NETFS_SREQ_RETRYING, &subreq->flags)) {126 set_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);127 return netfs_write_subrequest_terminated(subreq, -EAGAIN, false);128 }129#endif130 131 op = afs_alloc_operation(wreq->netfs_priv, vnode->volume);132 if (IS_ERR(op))133 return netfs_write_subrequest_terminated(subreq, -EAGAIN, false);134 135 afs_op_set_vnode(op, 0, vnode);136 op->file[0].dv_delta = 1;137 op->file[0].modification = true;138 op->store.pos = pos;139 op->store.size = len;140 op->flags |= AFS_OPERATION_UNINTR;141 op->ops = &afs_store_data_operation;142 143 afs_begin_vnode_operation(op);144 145 op->store.write_iter = &subreq->io_iter;146 op->store.i_size = umax(pos + len, vnode->netfs.remote_i_size);147 op->mtime = inode_get_mtime(&vnode->netfs.inode);148 149 afs_wait_for_operation(op);150 ret = afs_put_operation(op);151 switch (ret) {152 case -EACCES:153 case -EPERM:154 case -ENOKEY:155 case -EKEYEXPIRED:156 case -EKEYREJECTED:157 case -EKEYREVOKED:158 /* If there are more keys we can try, use the retry algorithm159 * to rotate the keys.160 */161 if (wreq->netfs_priv2)162 set_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);163 break;164 }165 166 netfs_write_subrequest_terminated(subreq, ret < 0 ? ret : subreq->len, false);167}168 169void afs_issue_write(struct netfs_io_subrequest *subreq)170{171 subreq->work.func = afs_issue_write_worker;172 if (!queue_work(system_unbound_wq, &subreq->work))173 WARN_ON_ONCE(1);174}175 176/*177 * Writeback calls this when it finds a folio that needs uploading. This isn't178 * called if writeback only has copy-to-cache to deal with.179 */180void afs_begin_writeback(struct netfs_io_request *wreq)181{182 afs_get_writeback_key(wreq);183 wreq->io_streams[0].avail = true;184}185 186/*187 * Prepare to retry the writes in request. Use this to try rotating the188 * available writeback keys.189 */190void afs_retry_request(struct netfs_io_request *wreq, struct netfs_io_stream *stream)191{192 struct netfs_io_subrequest *subreq =193 list_first_entry(&stream->subrequests,194 struct netfs_io_subrequest, rreq_link);195 196 switch (subreq->error) {197 case -EACCES:198 case -EPERM:199 case -ENOKEY:200 case -EKEYEXPIRED:201 case -EKEYREJECTED:202 case -EKEYREVOKED:203 afs_get_writeback_key(wreq);204 if (!wreq->netfs_priv)205 stream->failed = true;206 break;207 }208}209 210/*211 * write some of the pending data back to the server212 */213int afs_writepages(struct address_space *mapping, struct writeback_control *wbc)214{215 struct afs_vnode *vnode = AFS_FS_I(mapping->host);216 int ret;217 218 /* We have to be careful as we can end up racing with setattr()219 * truncating the pagecache since the caller doesn't take a lock here220 * to prevent it.221 */222 if (wbc->sync_mode == WB_SYNC_ALL)223 down_read(&vnode->validate_lock);224 else if (!down_read_trylock(&vnode->validate_lock))225 return 0;226 227 ret = netfs_writepages(mapping, wbc);228 up_read(&vnode->validate_lock);229 return ret;230}231 232/*233 * flush any dirty pages for this process, and check for write errors.234 * - the return status from this call provides a reliable indication of235 * whether any write errors occurred for this process.236 */237int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync)238{239 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));240 struct afs_file *af = file->private_data;241 int ret;242 243 _enter("{%llx:%llu},{n=%pD},%d",244 vnode->fid.vid, vnode->fid.vnode, file,245 datasync);246 247 ret = afs_validate(vnode, af->key);248 if (ret < 0)249 return ret;250 251 return file_write_and_wait_range(file, start, end);252}253 254/*255 * notification that a previously read-only page is about to become writable256 * - if it returns an error, the caller will deliver a bus error signal257 */258vm_fault_t afs_page_mkwrite(struct vm_fault *vmf)259{260 struct file *file = vmf->vma->vm_file;261 262 if (afs_validate(AFS_FS_I(file_inode(file)), afs_file_key(file)) < 0)263 return VM_FAULT_SIGBUS;264 return netfs_page_mkwrite(vmf, NULL);265}266 267/*268 * Prune the keys cached for writeback. The caller must hold vnode->wb_lock.269 */270void afs_prune_wb_keys(struct afs_vnode *vnode)271{272 LIST_HEAD(graveyard);273 struct afs_wb_key *wbk, *tmp;274 275 /* Discard unused keys */276 spin_lock(&vnode->wb_lock);277 278 if (!mapping_tagged(&vnode->netfs.inode.i_data, PAGECACHE_TAG_WRITEBACK) &&279 !mapping_tagged(&vnode->netfs.inode.i_data, PAGECACHE_TAG_DIRTY)) {280 list_for_each_entry_safe(wbk, tmp, &vnode->wb_keys, vnode_link) {281 if (refcount_read(&wbk->usage) == 1)282 list_move(&wbk->vnode_link, &graveyard);283 }284 }285 286 spin_unlock(&vnode->wb_lock);287 288 while (!list_empty(&graveyard)) {289 wbk = list_entry(graveyard.next, struct afs_wb_key, vnode_link);290 list_del(&wbk->vnode_link);291 afs_put_wb_key(wbk);292 }293}294