1/*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
4 * Copyright © 2001-2007 Red Hat, Inc.
5 * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
6 *
7 * Created by David Woodhouse <dwmw2@infradead.org>
8 *
9 * For licensing information, see the file 'LICENCE' in this directory.
10 *
11 */
12
13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15#include <linux/kernel.h>
16#include <linux/fs.h>
17#include <linux/time.h>
18#include <linux/pagemap.h>
19#include <linux/highmem.h>
20#include <linux/crc32.h>
21#include <linux/jffs2.h>
22#include "nodelist.h"
23
24static int jffs2_write_end(const struct kiocb *iocb,
25 struct address_space *mapping,
26 loff_t pos, unsigned len, unsigned copied,
27 struct folio *folio, void *fsdata);
28static int jffs2_write_begin(const struct kiocb *iocb,
29 struct address_space *mapping,
30 loff_t pos, unsigned len,
31 struct folio **foliop, void **fsdata);
32static int jffs2_read_folio(struct file *filp, struct folio *folio);
33
34int jffs2_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
35{
36 struct inode *inode = filp->f_mapping->host;
37 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
38 int ret;
39
40 ret = file_write_and_wait_range(file: filp, start, end);
41 if (ret)
42 return ret;
43
44 inode_lock(inode);
45 /* Trigger GC to flush any pending writes for this inode */
46 jffs2_flush_wbuf_gc(c, ino: inode->i_ino);
47 inode_unlock(inode);
48
49 return 0;
50}
51
52const struct file_operations jffs2_file_operations =
53{
54 .llseek = generic_file_llseek,
55 .open = generic_file_open,
56 .read_iter = generic_file_read_iter,
57 .write_iter = generic_file_write_iter,
58 .unlocked_ioctl=jffs2_ioctl,
59 .mmap_prepare = generic_file_readonly_mmap_prepare,
60 .fsync = jffs2_fsync,
61 .splice_read = filemap_splice_read,
62 .splice_write = iter_file_splice_write,
63};
64
65/* jffs2_file_inode_operations */
66
67const struct inode_operations jffs2_file_inode_operations =
68{
69 .get_inode_acl = jffs2_get_acl,
70 .set_acl = jffs2_set_acl,
71 .setattr = jffs2_setattr,
72 .listxattr = jffs2_listxattr,
73};
74
75const struct address_space_operations jffs2_file_address_operations =
76{
77 .read_folio = jffs2_read_folio,
78 .write_begin = jffs2_write_begin,
79 .write_end = jffs2_write_end,
80};
81
82static int jffs2_do_readpage_nolock(struct inode *inode, struct folio *folio)
83{
84 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
85 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
86 unsigned char *kaddr;
87 int ret;
88
89 jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n",
90 __func__, inode->i_ino, folio->index << PAGE_SHIFT);
91
92 BUG_ON(!folio_test_locked(folio));
93
94 kaddr = kmap_local_folio(folio, offset: 0);
95 ret = jffs2_read_inode_range(c, f, buf: kaddr, offset: folio->index << PAGE_SHIFT,
96 PAGE_SIZE);
97 kunmap_local(kaddr);
98
99 if (!ret)
100 folio_mark_uptodate(folio);
101
102 flush_dcache_folio(folio);
103
104 jffs2_dbg(2, "readpage finished\n");
105 return ret;
106}
107
108int __jffs2_read_folio(struct file *file, struct folio *folio)
109{
110 int ret = jffs2_do_readpage_nolock(inode: folio->mapping->host, folio);
111 folio_unlock(folio);
112 return ret;
113}
114
115static int jffs2_read_folio(struct file *file, struct folio *folio)
116{
117 struct jffs2_inode_info *f = JFFS2_INODE_INFO(folio->mapping->host);
118 int ret;
119
120 mutex_lock(&f->sem);
121 ret = __jffs2_read_folio(file, folio);
122 mutex_unlock(lock: &f->sem);
123 return ret;
124}
125
126static int jffs2_write_begin(const struct kiocb *iocb,
127 struct address_space *mapping,
128 loff_t pos, unsigned len,
129 struct folio **foliop, void **fsdata)
130{
131 struct folio *folio;
132 struct inode *inode = mapping->host;
133 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
134 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
135 pgoff_t index = pos >> PAGE_SHIFT;
136 int ret = 0;
137
138 jffs2_dbg(1, "%s()\n", __func__);
139
140 if (pos > inode->i_size) {
141 /* Make new hole frag from old EOF to new position */
142 struct jffs2_raw_inode ri;
143 struct jffs2_full_dnode *fn;
144 uint32_t alloc_len;
145
146 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new position\n",
147 (unsigned int)inode->i_size, (uint32_t)pos);
148
149 ret = jffs2_reserve_space(c, minsize: sizeof(ri), len: &alloc_len,
150 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
151 if (ret)
152 goto out_err;
153
154 mutex_lock(&f->sem);
155 memset(&ri, 0, sizeof(ri));
156
157 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
158 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
159 ri.totlen = cpu_to_je32(sizeof(ri));
160 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
161
162 ri.ino = cpu_to_je32(f->inocache->ino);
163 ri.version = cpu_to_je32(++f->highest_version);
164 ri.mode = cpu_to_jemode(inode->i_mode);
165 ri.uid = cpu_to_je16(i_uid_read(inode));
166 ri.gid = cpu_to_je16(i_gid_read(inode));
167 ri.isize = cpu_to_je32((uint32_t)pos);
168 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW());
169 ri.offset = cpu_to_je32(inode->i_size);
170 ri.dsize = cpu_to_je32((uint32_t)pos - inode->i_size);
171 ri.csize = cpu_to_je32(0);
172 ri.compr = JFFS2_COMPR_ZERO;
173 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
174 ri.data_crc = cpu_to_je32(0);
175
176 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
177
178 if (IS_ERR(fn)) {
179 ret = PTR_ERR(fn);
180 jffs2_complete_reservation(c);
181 mutex_unlock(&f->sem);
182 goto out_err;
183 }
184 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
185 if (f->metadata) {
186 jffs2_mark_node_obsolete(c, f->metadata->raw);
187 jffs2_free_full_dnode(f->metadata);
188 f->metadata = NULL;
189 }
190 if (ret) {
191 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
192 ret);
193 jffs2_mark_node_obsolete(c, fn->raw);
194 jffs2_free_full_dnode(fn);
195 jffs2_complete_reservation(c);
196 mutex_unlock(&f->sem);
197 goto out_err;
198 }
199 jffs2_complete_reservation(c);
200 inode->i_size = pos;
201 mutex_unlock(&f->sem);
202 }
203
204 /*
205 * While getting a page and reading data in, lock c->alloc_sem until
206 * the page is Uptodate. Otherwise GC task may attempt to read the same
207 * page in read_cache_page(), which causes a deadlock.
208 */
209 mutex_lock(&c->alloc_sem);
210 folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
211 mapping_gfp_mask(mapping));
212 if (IS_ERR(folio)) {
213 ret = PTR_ERR(folio);
214 goto release_sem;
215 }
216 *foliop = folio;
217
218 /*
219 * Read in the folio if it wasn't already present. Cannot optimize away
220 * the whole folio write case until jffs2_write_end can handle the
221 * case of a short-copy.
222 */
223 if (!folio_test_uptodate(folio)) {
224 mutex_lock(&f->sem);
225 ret = jffs2_do_readpage_nolock(inode, folio);
226 mutex_unlock(&f->sem);
227 if (ret) {
228 folio_unlock(folio);
229 folio_put(folio);
230 goto release_sem;
231 }
232 }
233 jffs2_dbg(1, "end write_begin(). folio->flags %lx\n", folio->flags.f);
234
235release_sem:
236 mutex_unlock(&c->alloc_sem);
237out_err:
238 return ret;
239}
240
241static int jffs2_write_end(const struct kiocb *iocb,
242 struct address_space *mapping,
243 loff_t pos, unsigned len, unsigned copied,
244 struct folio *folio, void *fsdata)
245{
246 /* Actually commit the write from the page cache page we're looking at.
247 * For now, we write the full page out each time. It sucks, but it's simple
248 */
249 struct inode *inode = mapping->host;
250 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
251 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
252 struct jffs2_raw_inode *ri;
253 unsigned start = pos & (PAGE_SIZE - 1);
254 unsigned end = start + copied;
255 unsigned aligned_start = start & ~3;
256 int ret = 0;
257 uint32_t writtenlen = 0;
258 void *buf;
259
260 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%llx, range %d-%d, flags %lx\n",
261 __func__, inode->i_ino, folio_pos(folio),
262 start, end, folio->flags.f);
263
264 /* We need to avoid deadlock with page_cache_read() in
265 jffs2_garbage_collect_pass(). So the folio must be
266 up to date to prevent page_cache_read() from trying
267 to re-lock it. */
268 BUG_ON(!folio_test_uptodate(folio));
269
270 if (end == PAGE_SIZE) {
271 /* When writing out the end of a page, write out the
272 _whole_ page. This helps to reduce the number of
273 nodes in files which have many short writes, like
274 syslog files. */
275 aligned_start = 0;
276 }
277
278 ri = jffs2_alloc_raw_inode();
279
280 if (!ri) {
281 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
282 __func__);
283 folio_unlock(folio);
284 folio_put(folio);
285 return -ENOMEM;
286 }
287
288 /* Set the fields that the generic jffs2_write_inode_range() code can't find */
289 ri->ino = cpu_to_je32(inode->i_ino);
290 ri->mode = cpu_to_jemode(inode->i_mode);
291 ri->uid = cpu_to_je16(i_uid_read(inode));
292 ri->gid = cpu_to_je16(i_gid_read(inode));
293 ri->isize = cpu_to_je32((uint32_t)inode->i_size);
294 ri->atime = ri->ctime = ri->mtime = cpu_to_je32(JFFS2_NOW());
295
296 buf = kmap_local_folio(folio, offset: aligned_start);
297 ret = jffs2_write_inode_range(c, f, ri, buf,
298 offset: folio_pos(folio) + aligned_start,
299 writelen: end - aligned_start, retlen: &writtenlen);
300 kunmap_local(buf);
301
302 if (ret)
303 mapping_set_error(mapping, error: ret);
304
305 /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
306 writtenlen -= min(writtenlen, (start - aligned_start));
307
308 if (writtenlen) {
309 if (inode->i_size < pos + writtenlen) {
310 inode->i_size = pos + writtenlen;
311 inode->i_blocks = (inode->i_size + 511) >> 9;
312
313 inode_set_mtime_to_ts(inode,
314 ts: inode_set_ctime_to_ts(inode, ITIME(je32_to_cpu(ri->ctime))));
315 }
316 }
317
318 jffs2_free_raw_inode(ri);
319
320 if (start+writtenlen < end) {
321 /* generic_file_write has written more to the page cache than we've
322 actually written to the medium. Mark the page !Uptodate so that
323 it gets reread */
324 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n",
325 __func__);
326 folio_clear_uptodate(folio);
327 }
328
329 jffs2_dbg(1, "%s() returning %d\n",
330 __func__, writtenlen > 0 ? writtenlen : ret);
331 folio_unlock(folio);
332 folio_put(folio);
333 return writtenlen > 0 ? writtenlen : ret;
334}
335

source code of linux/fs/jffs2/file.c