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
jffs2_fsync(struct file * filp,loff_t start,loff_t end,int datasync)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
jffs2_do_readpage_nolock(struct inode * inode,struct page * pg)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 ClearPageUptodate(pg);
100 SetPageError(pg);
101 } else {
102 SetPageUptodate(pg);
103 ClearPageError(pg);
104 }
105
106 flush_dcache_page(pg);
107 kunmap(pg);
108
109 jffs2_dbg(2, "readpage finished\n");
110 return ret;
111 }
112
__jffs2_read_folio(struct file * file,struct folio * folio)113 int __jffs2_read_folio(struct file *file, struct folio *folio)
114 {
115 int ret = jffs2_do_readpage_nolock(folio->mapping->host, &folio->page);
116 folio_unlock(folio);
117 return ret;
118 }
119
jffs2_read_folio(struct file * file,struct folio * folio)120 static int jffs2_read_folio(struct file *file, struct folio *folio)
121 {
122 struct jffs2_inode_info *f = JFFS2_INODE_INFO(folio->mapping->host);
123 int ret;
124
125 mutex_lock(&f->sem);
126 ret = __jffs2_read_folio(file, folio);
127 mutex_unlock(&f->sem);
128 return ret;
129 }
130
jffs2_write_begin(struct file * filp,struct address_space * mapping,loff_t pos,unsigned len,struct page ** pagep,void ** fsdata)131 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
132 loff_t pos, unsigned len,
133 struct page **pagep, void **fsdata)
134 {
135 struct page *pg;
136 struct inode *inode = mapping->host;
137 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
138 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
139 pgoff_t index = pos >> PAGE_SHIFT;
140 int ret = 0;
141
142 jffs2_dbg(1, "%s()\n", __func__);
143
144 if (pos > inode->i_size) {
145 /* Make new hole frag from old EOF to new position */
146 struct jffs2_raw_inode ri;
147 struct jffs2_full_dnode *fn;
148 uint32_t alloc_len;
149
150 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new position\n",
151 (unsigned int)inode->i_size, (uint32_t)pos);
152
153 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
154 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
155 if (ret)
156 goto out_err;
157
158 mutex_lock(&f->sem);
159 memset(&ri, 0, sizeof(ri));
160
161 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
162 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
163 ri.totlen = cpu_to_je32(sizeof(ri));
164 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
165
166 ri.ino = cpu_to_je32(f->inocache->ino);
167 ri.version = cpu_to_je32(++f->highest_version);
168 ri.mode = cpu_to_jemode(inode->i_mode);
169 ri.uid = cpu_to_je16(i_uid_read(inode));
170 ri.gid = cpu_to_je16(i_gid_read(inode));
171 ri.isize = cpu_to_je32((uint32_t)pos);
172 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW());
173 ri.offset = cpu_to_je32(inode->i_size);
174 ri.dsize = cpu_to_je32((uint32_t)pos - inode->i_size);
175 ri.csize = cpu_to_je32(0);
176 ri.compr = JFFS2_COMPR_ZERO;
177 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
178 ri.data_crc = cpu_to_je32(0);
179
180 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
181
182 if (IS_ERR(fn)) {
183 ret = PTR_ERR(fn);
184 jffs2_complete_reservation(c);
185 mutex_unlock(&f->sem);
186 goto out_err;
187 }
188 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
189 if (f->metadata) {
190 jffs2_mark_node_obsolete(c, f->metadata->raw);
191 jffs2_free_full_dnode(f->metadata);
192 f->metadata = NULL;
193 }
194 if (ret) {
195 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
196 ret);
197 jffs2_mark_node_obsolete(c, fn->raw);
198 jffs2_free_full_dnode(fn);
199 jffs2_complete_reservation(c);
200 mutex_unlock(&f->sem);
201 goto out_err;
202 }
203 jffs2_complete_reservation(c);
204 inode->i_size = pos;
205 mutex_unlock(&f->sem);
206 }
207
208 /*
209 * While getting a page and reading data in, lock c->alloc_sem until
210 * the page is Uptodate. Otherwise GC task may attempt to read the same
211 * page in read_cache_page(), which causes a deadlock.
212 */
213 mutex_lock(&c->alloc_sem);
214 pg = grab_cache_page_write_begin(mapping, index);
215 if (!pg) {
216 ret = -ENOMEM;
217 goto release_sem;
218 }
219 *pagep = pg;
220
221 /*
222 * Read in the page if it wasn't already present. Cannot optimize away
223 * the whole page write case until jffs2_write_end can handle the
224 * case of a short-copy.
225 */
226 if (!PageUptodate(pg)) {
227 mutex_lock(&f->sem);
228 ret = jffs2_do_readpage_nolock(inode, pg);
229 mutex_unlock(&f->sem);
230 if (ret) {
231 unlock_page(pg);
232 put_page(pg);
233 goto release_sem;
234 }
235 }
236 jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
237
238 release_sem:
239 mutex_unlock(&c->alloc_sem);
240 out_err:
241 return ret;
242 }
243
jffs2_write_end(struct file * filp,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * pg,void * fsdata)244 static int jffs2_write_end(struct file *filp, struct address_space *mapping,
245 loff_t pos, unsigned len, unsigned copied,
246 struct page *pg, void *fsdata)
247 {
248 /* Actually commit the write from the page cache page we're looking at.
249 * For now, we write the full page out each time. It sucks, but it's simple
250 */
251 struct inode *inode = mapping->host;
252 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
253 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
254 struct jffs2_raw_inode *ri;
255 unsigned start = pos & (PAGE_SIZE - 1);
256 unsigned end = start + copied;
257 unsigned aligned_start = start & ~3;
258 int ret = 0;
259 uint32_t writtenlen = 0;
260
261 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
262 __func__, inode->i_ino, pg->index << PAGE_SHIFT,
263 start, end, pg->flags);
264
265 /* We need to avoid deadlock with page_cache_read() in
266 jffs2_garbage_collect_pass(). So the page must be
267 up to date to prevent page_cache_read() from trying
268 to re-lock it. */
269 BUG_ON(!PageUptodate(pg));
270
271 if (end == PAGE_SIZE) {
272 /* When writing out the end of a page, write out the
273 _whole_ page. This helps to reduce the number of
274 nodes in files which have many short writes, like
275 syslog files. */
276 aligned_start = 0;
277 }
278
279 ri = jffs2_alloc_raw_inode();
280
281 if (!ri) {
282 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
283 __func__);
284 unlock_page(pg);
285 put_page(pg);
286 return -ENOMEM;
287 }
288
289 /* Set the fields that the generic jffs2_write_inode_range() code can't find */
290 ri->ino = cpu_to_je32(inode->i_ino);
291 ri->mode = cpu_to_jemode(inode->i_mode);
292 ri->uid = cpu_to_je16(i_uid_read(inode));
293 ri->gid = cpu_to_je16(i_gid_read(inode));
294 ri->isize = cpu_to_je32((uint32_t)inode->i_size);
295 ri->atime = ri->ctime = ri->mtime = cpu_to_je32(JFFS2_NOW());
296
297 /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
298 hurt to do it again. The alternative is ifdefs, which are ugly. */
299 kmap(pg);
300
301 ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
302 (pg->index << PAGE_SHIFT) + aligned_start,
303 end - aligned_start, &writtenlen);
304
305 kunmap(pg);
306
307 if (ret) {
308 /* There was an error writing. */
309 SetPageError(pg);
310 }
311
312 /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
313 writtenlen -= min(writtenlen, (start - aligned_start));
314
315 if (writtenlen) {
316 if (inode->i_size < pos + writtenlen) {
317 inode->i_size = pos + writtenlen;
318 inode->i_blocks = (inode->i_size + 511) >> 9;
319
320 inode->i_mtime = inode_set_ctime_to_ts(inode,
321 ITIME(je32_to_cpu(ri->ctime)));
322 }
323 }
324
325 jffs2_free_raw_inode(ri);
326
327 if (start+writtenlen < end) {
328 /* generic_file_write has written more to the page cache than we've
329 actually written to the medium. Mark the page !Uptodate so that
330 it gets reread */
331 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n",
332 __func__);
333 SetPageError(pg);
334 ClearPageUptodate(pg);
335 }
336
337 jffs2_dbg(1, "%s() returning %d\n",
338 __func__, writtenlen > 0 ? writtenlen : ret);
339 unlock_page(pg);
340 put_page(pg);
341 return writtenlen > 0 ? writtenlen : ret;
342 }
343