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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 */
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 the
32 * writes on the vnode. *_wbk will contain the last writeback key used or NULL
33 * and we need to start from there if it's set.
34 */
35static int afs_get_writeback_key(struct afs_vnode *vnode,
36 struct afs_wb_key **_wbk)
37{
38 struct afs_wb_key *wbk = NULL;
39 struct list_head *p;
40 int ret = -ENOKEY, ret2;
41
42 spin_lock(&vnode->wb_lock);
43 if (*_wbk)
44 p = (*_wbk)->vnode_link.next;
45 else
46 p = vnode->wb_keys.next;
47
48 while (p != &vnode->wb_keys) {
49 wbk = list_entry(p, struct afs_wb_key, vnode_link);
50 _debug("wbk %u", key_serial(wbk->key));
51 ret2 = key_validate(wbk->key);
52 if (ret2 == 0) {
53 refcount_inc(&wbk->usage);
54 _debug("USE WB KEY %u", key_serial(wbk->key));
55 break;
56 }
57
58 wbk = NULL;
59 if (ret == -ENOKEY)
60 ret = ret2;
61 p = p->next;
62 }
63
64 spin_unlock(&vnode->wb_lock);
65 if (*_wbk)
66 afs_put_wb_key(*_wbk);
67 *_wbk = wbk;
68 return 0;
69}
70
71static void afs_store_data_success(struct afs_operation *op)
72{
73 struct afs_vnode *vnode = op->file[0].vnode;
74
75 op->ctime = op->file[0].scb.status.mtime_client;
76 afs_vnode_commit_status(op, &op->file[0]);
77 if (!afs_op_error(op)) {
78 if (!op->store.laundering)
79 afs_pages_written_back(vnode, op->store.pos, op->store.size);
80 afs_stat_v(vnode, n_stores);
81 atomic_long_add(op->store.size, &afs_v2net(vnode)->n_store_bytes);
82 }
83}
84
85static const struct afs_operation_ops afs_store_data_operation = {
86 .issue_afs_rpc = afs_fs_store_data,
87 .issue_yfs_rpc = yfs_fs_store_data,
88 .success = afs_store_data_success,
89};
90
91/*
92 * write to a file
93 */
94static int afs_store_data(struct afs_vnode *vnode, struct iov_iter *iter, loff_t pos,
95 bool laundering)
96{
97 struct afs_operation *op;
98 struct afs_wb_key *wbk = NULL;
99 loff_t size = iov_iter_count(iter);
100 int ret = -ENOKEY;
101
102 _enter("%s{%llx:%llu.%u},%llx,%llx",
103 vnode->volume->name,
104 vnode->fid.vid,
105 vnode->fid.vnode,
106 vnode->fid.unique,
107 size, pos);
108
109 ret = afs_get_writeback_key(vnode, &wbk);
110 if (ret) {
111 _leave(" = %d [no keys]", ret);
112 return ret;
113 }
114
115 op = afs_alloc_operation(wbk->key, vnode->volume);
116 if (IS_ERR(op)) {
117 afs_put_wb_key(wbk);
118 return -ENOMEM;
119 }
120
121 afs_op_set_vnode(op, 0, vnode);
122 op->file[0].dv_delta = 1;
123 op->file[0].modification = true;
124 op->store.pos = pos;
125 op->store.size = size;
126 op->store.laundering = laundering;
127 op->flags |= AFS_OPERATION_UNINTR;
128 op->ops = &afs_store_data_operation;
129
130try_next_key:
131 afs_begin_vnode_operation(op);
132
133 op->store.write_iter = iter;
134 op->store.i_size = max(pos + size, vnode->netfs.remote_i_size);
135 op->mtime = inode_get_mtime(&vnode->netfs.inode);
136
137 afs_wait_for_operation(op);
138
139 switch (afs_op_error(op)) {
140 case -EACCES:
141 case -EPERM:
142 case -ENOKEY:
143 case -EKEYEXPIRED:
144 case -EKEYREJECTED:
145 case -EKEYREVOKED:
146 _debug("next");
147
148 ret = afs_get_writeback_key(vnode, &wbk);
149 if (ret == 0) {
150 key_put(op->key);
151 op->key = key_get(wbk->key);
152 goto try_next_key;
153 }
154 break;
155 }
156
157 afs_put_wb_key(wbk);
158 _leave(" = %d", afs_op_error(op));
159 return afs_put_operation(op);
160}
161
162static void afs_upload_to_server(struct netfs_io_subrequest *subreq)
163{
164 struct afs_vnode *vnode = AFS_FS_I(subreq->rreq->inode);
165 ssize_t ret;
166
167 _enter("%x[%x],%zx",
168 subreq->rreq->debug_id, subreq->debug_index, subreq->io_iter.count);
169
170 trace_netfs_sreq(subreq, netfs_sreq_trace_submit);
171 ret = afs_store_data(vnode, &subreq->io_iter, subreq->start,
172 subreq->rreq->origin == NETFS_LAUNDER_WRITE);
173 netfs_write_subrequest_terminated(subreq, ret < 0 ? ret : subreq->len,
174 false);
175}
176
177static void afs_upload_to_server_worker(struct work_struct *work)
178{
179 struct netfs_io_subrequest *subreq =
180 container_of(work, struct netfs_io_subrequest, work);
181
182 afs_upload_to_server(subreq);
183}
184
185/*
186 * Set up write requests for a writeback slice. We need to add a write request
187 * for each write we want to make.
188 */
189void afs_create_write_requests(struct netfs_io_request *wreq, loff_t start, size_t len)
190{
191 struct netfs_io_subrequest *subreq;
192
193 _enter("%x,%llx-%llx", wreq->debug_id, start, start + len);
194
195 subreq = netfs_create_write_request(wreq, NETFS_UPLOAD_TO_SERVER,
196 start, len, afs_upload_to_server_worker);
197 if (subreq)
198 netfs_queue_write_request(subreq);
199}
200
201/*
202 * write some of the pending data back to the server
203 */
204int afs_writepages(struct address_space *mapping, struct writeback_control *wbc)
205{
206 struct afs_vnode *vnode = AFS_FS_I(mapping->host);
207 int ret;
208
209 /* We have to be careful as we can end up racing with setattr()
210 * truncating the pagecache since the caller doesn't take a lock here
211 * to prevent it.
212 */
213 if (wbc->sync_mode == WB_SYNC_ALL)
214 down_read(&vnode->validate_lock);
215 else if (!down_read_trylock(&vnode->validate_lock))
216 return 0;
217
218 ret = netfs_writepages(mapping, wbc);
219 up_read(&vnode->validate_lock);
220 return ret;
221}
222
223/*
224 * flush any dirty pages for this process, and check for write errors.
225 * - the return status from this call provides a reliable indication of
226 * whether any write errors occurred for this process.
227 */
228int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
229{
230 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
231 struct afs_file *af = file->private_data;
232 int ret;
233
234 _enter("{%llx:%llu},{n=%pD},%d",
235 vnode->fid.vid, vnode->fid.vnode, file,
236 datasync);
237
238 ret = afs_validate(vnode, af->key);
239 if (ret < 0)
240 return ret;
241
242 return file_write_and_wait_range(file, start, end);
243}
244
245/*
246 * notification that a previously read-only page is about to become writable
247 * - if it returns an error, the caller will deliver a bus error signal
248 */
249vm_fault_t afs_page_mkwrite(struct vm_fault *vmf)
250{
251 struct file *file = vmf->vma->vm_file;
252
253 if (afs_validate(AFS_FS_I(file_inode(file)), afs_file_key(file)) < 0)
254 return VM_FAULT_SIGBUS;
255 return netfs_page_mkwrite(vmf, NULL);
256}
257
258/*
259 * Prune the keys cached for writeback. The caller must hold vnode->wb_lock.
260 */
261void afs_prune_wb_keys(struct afs_vnode *vnode)
262{
263 LIST_HEAD(graveyard);
264 struct afs_wb_key *wbk, *tmp;
265
266 /* Discard unused keys */
267 spin_lock(&vnode->wb_lock);
268
269 if (!mapping_tagged(&vnode->netfs.inode.i_data, PAGECACHE_TAG_WRITEBACK) &&
270 !mapping_tagged(&vnode->netfs.inode.i_data, PAGECACHE_TAG_DIRTY)) {
271 list_for_each_entry_safe(wbk, tmp, &vnode->wb_keys, vnode_link) {
272 if (refcount_read(&wbk->usage) == 1)
273 list_move(&wbk->vnode_link, &graveyard);
274 }
275 }
276
277 spin_unlock(&vnode->wb_lock);
278
279 while (!list_empty(&graveyard)) {
280 wbk = list_entry(graveyard.next, struct afs_wb_key, vnode_link);
281 list_del(&wbk->vnode_link);
282 afs_put_wb_key(wbk);
283 }
284}
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 */
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 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 */
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 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
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_len
88 * 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 //else
97 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 injection
122 if (subreq->debug_index == 3)
123 return netfs_write_subrequest_terminated(subreq, -ENOANO, false);
124
125 if (!subreq->retry_count) {
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 0:
153 __set_bit(NETFS_SREQ_MADE_PROGRESS, &subreq->flags);
154 break;
155 case -EACCES:
156 case -EPERM:
157 case -ENOKEY:
158 case -EKEYEXPIRED:
159 case -EKEYREJECTED:
160 case -EKEYREVOKED:
161 /* If there are more keys we can try, use the retry algorithm
162 * to rotate the keys.
163 */
164 if (wreq->netfs_priv2)
165 set_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);
166 break;
167 }
168
169 netfs_write_subrequest_terminated(subreq, ret < 0 ? ret : subreq->len, false);
170}
171
172void afs_issue_write(struct netfs_io_subrequest *subreq)
173{
174 subreq->work.func = afs_issue_write_worker;
175 if (!queue_work(system_unbound_wq, &subreq->work))
176 WARN_ON_ONCE(1);
177}
178
179/*
180 * Writeback calls this when it finds a folio that needs uploading. This isn't
181 * called if writeback only has copy-to-cache to deal with.
182 */
183void afs_begin_writeback(struct netfs_io_request *wreq)
184{
185 afs_get_writeback_key(wreq);
186 wreq->io_streams[0].avail = true;
187}
188
189/*
190 * Prepare to retry the writes in request. Use this to try rotating the
191 * available writeback keys.
192 */
193void afs_retry_request(struct netfs_io_request *wreq, struct netfs_io_stream *stream)
194{
195 struct netfs_io_subrequest *subreq =
196 list_first_entry(&stream->subrequests,
197 struct netfs_io_subrequest, rreq_link);
198
199 switch (subreq->error) {
200 case -EACCES:
201 case -EPERM:
202 case -ENOKEY:
203 case -EKEYEXPIRED:
204 case -EKEYREJECTED:
205 case -EKEYREVOKED:
206 afs_get_writeback_key(wreq);
207 if (!wreq->netfs_priv)
208 stream->failed = true;
209 break;
210 }
211}
212
213/*
214 * write some of the pending data back to the server
215 */
216int afs_writepages(struct address_space *mapping, struct writeback_control *wbc)
217{
218 struct afs_vnode *vnode = AFS_FS_I(mapping->host);
219 int ret;
220
221 /* We have to be careful as we can end up racing with setattr()
222 * truncating the pagecache since the caller doesn't take a lock here
223 * to prevent it.
224 */
225 if (wbc->sync_mode == WB_SYNC_ALL)
226 down_read(&vnode->validate_lock);
227 else if (!down_read_trylock(&vnode->validate_lock))
228 return 0;
229
230 ret = netfs_writepages(mapping, wbc);
231 up_read(&vnode->validate_lock);
232 return ret;
233}
234
235/*
236 * flush any dirty pages for this process, and check for write errors.
237 * - the return status from this call provides a reliable indication of
238 * whether any write errors occurred for this process.
239 */
240int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
241{
242 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
243 struct afs_file *af = file->private_data;
244 int ret;
245
246 _enter("{%llx:%llu},{n=%pD},%d",
247 vnode->fid.vid, vnode->fid.vnode, file,
248 datasync);
249
250 ret = afs_validate(vnode, af->key);
251 if (ret < 0)
252 return ret;
253
254 return file_write_and_wait_range(file, start, end);
255}
256
257/*
258 * notification that a previously read-only page is about to become writable
259 * - if it returns an error, the caller will deliver a bus error signal
260 */
261vm_fault_t afs_page_mkwrite(struct vm_fault *vmf)
262{
263 struct file *file = vmf->vma->vm_file;
264
265 if (afs_validate(AFS_FS_I(file_inode(file)), afs_file_key(file)) < 0)
266 return VM_FAULT_SIGBUS;
267 return netfs_page_mkwrite(vmf, NULL);
268}
269
270/*
271 * Prune the keys cached for writeback. The caller must hold vnode->wb_lock.
272 */
273void afs_prune_wb_keys(struct afs_vnode *vnode)
274{
275 LIST_HEAD(graveyard);
276 struct afs_wb_key *wbk, *tmp;
277
278 /* Discard unused keys */
279 spin_lock(&vnode->wb_lock);
280
281 if (!mapping_tagged(&vnode->netfs.inode.i_data, PAGECACHE_TAG_WRITEBACK) &&
282 !mapping_tagged(&vnode->netfs.inode.i_data, PAGECACHE_TAG_DIRTY)) {
283 list_for_each_entry_safe(wbk, tmp, &vnode->wb_keys, vnode_link) {
284 if (refcount_read(&wbk->usage) == 1)
285 list_move(&wbk->vnode_link, &graveyard);
286 }
287 }
288
289 spin_unlock(&vnode->wb_lock);
290
291 while (!list_empty(&graveyard)) {
292 wbk = list_entry(graveyard.next, struct afs_wb_key, vnode_link);
293 list_del(&wbk->vnode_link);
294 afs_put_wb_key(wbk);
295 }
296}