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
24 static int jffs2_write_end(struct file *filp, struct address_space *mapping,
25 loff_t pos, unsigned len, unsigned copied,
26 struct page *pg, void *fsdata);
27 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
28 loff_t pos, unsigned len,
29 struct page **pagep, void **fsdata);
30 static int jffs2_read_folio(struct file *filp, struct folio *folio);
31
32 int jffs2_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
33 {
34 struct inode *inode = filp->f_mapping->host;
35 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
36 int ret;
37
38 ret = file_write_and_wait_range(filp, start, end);
39 if (ret)
40 return ret;
41
42 inode_lock(inode);
43 /* Trigger GC to flush any pending writes for this inode */
44 jffs2_flush_wbuf_gc(c, inode->i_ino);
45 inode_unlock(inode);
46
47 return 0;
48 }
49
50 const struct file_operations jffs2_file_operations =
51 {
52 .llseek = generic_file_llseek,
53 .open = generic_file_open,
54 .read_iter = generic_file_read_iter,
55 .write_iter = generic_file_write_iter,
56 .unlocked_ioctl=jffs2_ioctl,
57 .mmap = generic_file_readonly_mmap,
58 .fsync = jffs2_fsync,
59 .splice_read = filemap_splice_read,
60 .splice_write = iter_file_splice_write,
61 };
62
63 /* jffs2_file_inode_operations */
64
65 const struct inode_operations jffs2_file_inode_operations =
66 {
67 .get_inode_acl = jffs2_get_acl,
68 .set_acl = jffs2_set_acl,
69 .setattr = jffs2_setattr,
70 .listxattr = jffs2_listxattr,
71 };
72
73 const struct address_space_operations jffs2_file_address_operations =
74 {
75 .read_folio = jffs2_read_folio,
76 .write_begin = jffs2_write_begin,
77 .write_end = jffs2_write_end,
78 };
79
80 static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
81 {
82 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
83 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
84 unsigned char *pg_buf;
85 int ret;
86
87 jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n",
88 __func__, inode->i_ino, pg->index << PAGE_SHIFT);
89
90 BUG_ON(!PageLocked(pg));
91
92 pg_buf = kmap(pg);
93 /* FIXME: Can kmap fail? */
94
95 ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_SHIFT,
96 PAGE_SIZE);
97
98 if (!ret)
99 SetPageUptodate(pg);
100
101 flush_dcache_page(pg);
102 kunmap(pg);
103
104 jffs2_dbg(2, "readpage finished\n");
105 return ret;
106 }
107
108 int __jffs2_read_folio(struct file *file, struct folio *folio)
109 {
110 int ret = jffs2_do_readpage_nolock(folio->mapping->host, &folio->page);
111 folio_unlock(folio);
112 return ret;
113 }
114
115 static 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(&f->sem);
123 return ret;
124 }
125
126 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
127 loff_t pos, unsigned len,
128 struct page **pagep, void **fsdata)
129 {
130 struct page *pg;
131 struct inode *inode = mapping->host;
132 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
133 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
134 pgoff_t index = pos >> PAGE_SHIFT;
135 int ret = 0;
136
137 jffs2_dbg(1, "%s()\n", __func__);
138
139 if (pos > inode->i_size) {
140 /* Make new hole frag from old EOF to new position */
141 struct jffs2_raw_inode ri;
142 struct jffs2_full_dnode *fn;
143 uint32_t alloc_len;
144
145 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new position\n",
146 (unsigned int)inode->i_size, (uint32_t)pos);
147
148 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
149 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
150 if (ret)
151 goto out_err;
152
153 mutex_lock(&f->sem);
154 memset(&ri, 0, sizeof(ri));
155
156 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
157 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
158 ri.totlen = cpu_to_je32(sizeof(ri));
159 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
160
161 ri.ino = cpu_to_je32(f->inocache->ino);
162 ri.version = cpu_to_je32(++f->highest_version);
163 ri.mode = cpu_to_jemode(inode->i_mode);
164 ri.uid = cpu_to_je16(i_uid_read(inode));
165 ri.gid = cpu_to_je16(i_gid_read(inode));
166 ri.isize = cpu_to_je32((uint32_t)pos);
167 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW());
168 ri.offset = cpu_to_je32(inode->i_size);
169 ri.dsize = cpu_to_je32((uint32_t)pos - inode->i_size);
170 ri.csize = cpu_to_je32(0);
171 ri.compr = JFFS2_COMPR_ZERO;
172 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
173 ri.data_crc = cpu_to_je32(0);
174
175 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
176
177 if (IS_ERR(fn)) {
178 ret = PTR_ERR(fn);
179 jffs2_complete_reservation(c);
180 mutex_unlock(&f->sem);
181 goto out_err;
182 }
183 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
184 if (f->metadata) {
185 jffs2_mark_node_obsolete(c, f->metadata->raw);
186 jffs2_free_full_dnode(f->metadata);
187 f->metadata = NULL;
188 }
189 if (ret) {
190 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
191 ret);
192 jffs2_mark_node_obsolete(c, fn->raw);
193 jffs2_free_full_dnode(fn);
194 jffs2_complete_reservation(c);
195 mutex_unlock(&f->sem);
196 goto out_err;
197 }
198 jffs2_complete_reservation(c);
199 inode->i_size = pos;
200 mutex_unlock(&f->sem);
201 }
202
203 /*
204 * While getting a page and reading data in, lock c->alloc_sem until
205 * the page is Uptodate. Otherwise GC task may attempt to read the same
206 * page in read_cache_page(), which causes a deadlock.
207 */
208 mutex_lock(&c->alloc_sem);
209 pg = grab_cache_page_write_begin(mapping, index);
210 if (!pg) {
211 ret = -ENOMEM;
212 goto release_sem;
213 }
214 *pagep = pg;
215
216 /*
217 * Read in the page if it wasn't already present. Cannot optimize away
218 * the whole page write case until jffs2_write_end can handle the
219 * case of a short-copy.
220 */
221 if (!PageUptodate(pg)) {
222 mutex_lock(&f->sem);
223 ret = jffs2_do_readpage_nolock(inode, pg);
224 mutex_unlock(&f->sem);
225 if (ret) {
226 unlock_page(pg);
227 put_page(pg);
228 goto release_sem;
229 }
230 }
231 jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
232
233 release_sem:
234 mutex_unlock(&c->alloc_sem);
235 out_err:
236 return ret;
237 }
238
239 static int jffs2_write_end(struct file *filp, struct address_space *mapping,
240 loff_t pos, unsigned len, unsigned copied,
241 struct page *pg, void *fsdata)
242 {
243 /* Actually commit the write from the page cache page we're looking at.
244 * For now, we write the full page out each time. It sucks, but it's simple
245 */
246 struct inode *inode = mapping->host;
247 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
248 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
249 struct jffs2_raw_inode *ri;
250 unsigned start = pos & (PAGE_SIZE - 1);
251 unsigned end = start + copied;
252 unsigned aligned_start = start & ~3;
253 int ret = 0;
254 uint32_t writtenlen = 0;
255
256 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
257 __func__, inode->i_ino, pg->index << PAGE_SHIFT,
258 start, end, pg->flags);
259
260 /* We need to avoid deadlock with page_cache_read() in
261 jffs2_garbage_collect_pass(). So the page must be
262 up to date to prevent page_cache_read() from trying
263 to re-lock it. */
264 BUG_ON(!PageUptodate(pg));
265
266 if (end == PAGE_SIZE) {
267 /* When writing out the end of a page, write out the
268 _whole_ page. This helps to reduce the number of
269 nodes in files which have many short writes, like
270 syslog files. */
271 aligned_start = 0;
272 }
273
274 ri = jffs2_alloc_raw_inode();
275
276 if (!ri) {
277 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
278 __func__);
279 unlock_page(pg);
280 put_page(pg);
281 return -ENOMEM;
282 }
283
284 /* Set the fields that the generic jffs2_write_inode_range() code can't find */
285 ri->ino = cpu_to_je32(inode->i_ino);
286 ri->mode = cpu_to_jemode(inode->i_mode);
287 ri->uid = cpu_to_je16(i_uid_read(inode));
288 ri->gid = cpu_to_je16(i_gid_read(inode));
289 ri->isize = cpu_to_je32((uint32_t)inode->i_size);
290 ri->atime = ri->ctime = ri->mtime = cpu_to_je32(JFFS2_NOW());
291
292 /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
293 hurt to do it again. The alternative is ifdefs, which are ugly. */
294 kmap(pg);
295
296 ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
297 (pg->index << PAGE_SHIFT) + aligned_start,
298 end - aligned_start, &writtenlen);
299
300 kunmap(pg);
301
302 if (ret)
303 mapping_set_error(mapping, 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 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 ClearPageUptodate(pg);
327 }
328
329 jffs2_dbg(1, "%s() returning %d\n",
330 __func__, writtenlen > 0 ? writtenlen : ret);
331 unlock_page(pg);
332 put_page(pg);
333 return writtenlen > 0 ? writtenlen : ret;
334 }
335
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