1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* handling of writes to regular files and writing back to the server 3 * 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 server 20 */ 21 static 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 the 32 * writes on the vnode. wreq->netfs_priv2 will contain the last writeback key 33 * 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 */ 36 static 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 else 49 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 67 static 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 80 static 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_len 88 * parameter. 89 */ 90 void afs_prepare_write(struct netfs_io_subrequest *subreq) 91 { 92 //if (test_bit(NETFS_SREQ_RETRYING, &subreq->flags)) 93 // subreq->max_len = 512 * 1024; 94 //else 95 subreq->max_len = 256 * 1024 * 1024; 96 } 97 98 /* 99 * Issue a subrequest to write to the server. 100 */ 101 static void afs_issue_write_worker(struct work_struct *work) 102 { 103 struct netfs_io_subrequest *subreq = container_of(work, struct netfs_io_subrequest, work); 104 struct netfs_io_request *wreq = subreq->rreq; 105 struct afs_operation *op; 106 struct afs_vnode *vnode = AFS_FS_I(wreq->inode); 107 unsigned long long pos = subreq->start + subreq->transferred; 108 size_t len = subreq->len - subreq->transferred; 109 int ret = -ENOKEY; 110 111 _enter("R=%x[%x],%s{%llx:%llu.%u},%llx,%zx", 112 wreq->debug_id, subreq->debug_index, 113 vnode->volume->name, 114 vnode->fid.vid, 115 vnode->fid.vnode, 116 vnode->fid.unique, 117 pos, len); 118 119 #if 0 // Error injection 120 if (subreq->debug_index == 3) 121 return netfs_write_subrequest_terminated(subreq, -ENOANO, false); 122 123 if (!test_bit(NETFS_SREQ_RETRYING, &subreq->flags)) { 124 set_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags); 125 return netfs_write_subrequest_terminated(subreq, -EAGAIN, false); 126 } 127 #endif 128 129 op = afs_alloc_operation(wreq->netfs_priv, vnode->volume); 130 if (IS_ERR(op)) 131 return netfs_write_subrequest_terminated(subreq, -EAGAIN, false); 132 133 afs_op_set_vnode(op, 0, vnode); 134 op->file[0].dv_delta = 1; 135 op->file[0].modification = true; 136 op->store.pos = pos; 137 op->store.size = len; 138 op->flags |= AFS_OPERATION_UNINTR; 139 op->ops = &afs_store_data_operation; 140 141 afs_begin_vnode_operation(op); 142 143 op->store.write_iter = &subreq->io_iter; 144 op->store.i_size = umax(pos + len, vnode->netfs.remote_i_size); 145 op->mtime = inode_get_mtime(&vnode->netfs.inode); 146 147 afs_wait_for_operation(op); 148 ret = afs_put_operation(op); 149 switch (ret) { 150 case -EACCES: 151 case -EPERM: 152 case -ENOKEY: 153 case -EKEYEXPIRED: 154 case -EKEYREJECTED: 155 case -EKEYREVOKED: 156 /* If there are more keys we can try, use the retry algorithm 157 * to rotate the keys. 158 */ 159 if (wreq->netfs_priv2) 160 set_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags); 161 break; 162 } 163 164 netfs_write_subrequest_terminated(subreq, ret < 0 ? ret : subreq->len, false); 165 } 166 167 void afs_issue_write(struct netfs_io_subrequest *subreq) 168 { 169 subreq->work.func = afs_issue_write_worker; 170 if (!queue_work(system_unbound_wq, &subreq->work)) 171 WARN_ON_ONCE(1); 172 } 173 174 /* 175 * Writeback calls this when it finds a folio that needs uploading. This isn't 176 * called if writeback only has copy-to-cache to deal with. 177 */ 178 void afs_begin_writeback(struct netfs_io_request *wreq) 179 { 180 afs_get_writeback_key(wreq); 181 wreq->io_streams[0].avail = true; 182 } 183 184 /* 185 * Prepare to retry the writes in request. Use this to try rotating the 186 * available writeback keys. 187 */ 188 void afs_retry_request(struct netfs_io_request *wreq, struct netfs_io_stream *stream) 189 { 190 struct netfs_io_subrequest *subreq = 191 list_first_entry(&stream->subrequests, 192 struct netfs_io_subrequest, rreq_link); 193 194 switch (subreq->error) { 195 case -EACCES: 196 case -EPERM: 197 case -ENOKEY: 198 case -EKEYEXPIRED: 199 case -EKEYREJECTED: 200 case -EKEYREVOKED: 201 afs_get_writeback_key(wreq); 202 if (!wreq->netfs_priv) 203 stream->failed = true; 204 break; 205 } 206 } 207 208 /* 209 * write some of the pending data back to the server 210 */ 211 int afs_writepages(struct address_space *mapping, struct writeback_control *wbc) 212 { 213 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 214 int ret; 215 216 /* We have to be careful as we can end up racing with setattr() 217 * truncating the pagecache since the caller doesn't take a lock here 218 * to prevent it. 219 */ 220 if (wbc->sync_mode == WB_SYNC_ALL) 221 down_read(&vnode->validate_lock); 222 else if (!down_read_trylock(&vnode->validate_lock)) 223 return 0; 224 225 ret = netfs_writepages(mapping, wbc); 226 up_read(&vnode->validate_lock); 227 return ret; 228 } 229 230 /* 231 * flush any dirty pages for this process, and check for write errors. 232 * - the return status from this call provides a reliable indication of 233 * whether any write errors occurred for this process. 234 */ 235 int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync) 236 { 237 struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); 238 struct afs_file *af = file->private_data; 239 int ret; 240 241 _enter("{%llx:%llu},{n=%pD},%d", 242 vnode->fid.vid, vnode->fid.vnode, file, 243 datasync); 244 245 ret = afs_validate(vnode, af->key); 246 if (ret < 0) 247 return ret; 248 249 return file_write_and_wait_range(file, start, end); 250 } 251 252 /* 253 * notification that a previously read-only page is about to become writable 254 * - if it returns an error, the caller will deliver a bus error signal 255 */ 256 vm_fault_t afs_page_mkwrite(struct vm_fault *vmf) 257 { 258 struct file *file = vmf->vma->vm_file; 259 260 if (afs_validate(AFS_FS_I(file_inode(file)), afs_file_key(file)) < 0) 261 return VM_FAULT_SIGBUS; 262 return netfs_page_mkwrite(vmf, NULL); 263 } 264 265 /* 266 * Prune the keys cached for writeback. The caller must hold vnode->wb_lock. 267 */ 268 void afs_prune_wb_keys(struct afs_vnode *vnode) 269 { 270 LIST_HEAD(graveyard); 271 struct afs_wb_key *wbk, *tmp; 272 273 /* Discard unused keys */ 274 spin_lock(&vnode->wb_lock); 275 276 if (!mapping_tagged(&vnode->netfs.inode.i_data, PAGECACHE_TAG_WRITEBACK) && 277 !mapping_tagged(&vnode->netfs.inode.i_data, PAGECACHE_TAG_DIRTY)) { 278 list_for_each_entry_safe(wbk, tmp, &vnode->wb_keys, vnode_link) { 279 if (refcount_read(&wbk->usage) == 1) 280 list_move(&wbk->vnode_link, &graveyard); 281 } 282 } 283 284 spin_unlock(&vnode->wb_lock); 285 286 while (!list_empty(&graveyard)) { 287 wbk = list_entry(graveyard.next, struct afs_wb_key, vnode_link); 288 list_del(&wbk->vnode_link); 289 afs_put_wb_key(wbk); 290 } 291 } 292