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 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 //else 97 stream->sreq_max_len = 256 * 1024 * 1024; 98 } 99 100 /* 101 * Issue a subrequest to write to the server. 102 */ 103 static 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 injection 122 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 #endif 130 131 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 algorithm 159 * 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 } 168 169 void 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't 178 * called if writeback only has copy-to-cache to deal with. 179 */ 180 void 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 the 188 * available writeback keys. 189 */ 190 void 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 server 212 */ 213 int 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 here 220 * 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 of 235 * whether any write errors occurred for this process. 236 */ 237 int 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 writable 256 * - if it returns an error, the caller will deliver a bus error signal 257 */ 258 vm_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 */ 270 void 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