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, unsigned flags,
29 struct page **pagep, void **fsdata);
30 static int jffs2_readpage (struct file *filp, struct page *pg);
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 = generic_file_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_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 .readpage = jffs2_readpage,
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_do_readpage_unlock(void * data,struct page * pg)113 int jffs2_do_readpage_unlock(void *data, struct page *pg)
114 {
115 int ret = jffs2_do_readpage_nolock(data, pg);
116 unlock_page(pg);
117 return ret;
118 }
119
120
jffs2_readpage(struct file * filp,struct page * pg)121 static int jffs2_readpage (struct file *filp, struct page *pg)
122 {
123 struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
124 int ret;
125
126 mutex_lock(&f->sem);
127 ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
128 mutex_unlock(&f->sem);
129 return ret;
130 }
131
jffs2_write_begin(struct file * filp,struct address_space * mapping,loff_t pos,unsigned len,unsigned flags,struct page ** pagep,void ** fsdata)132 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
133 loff_t pos, unsigned len, unsigned flags,
134 struct page **pagep, void **fsdata)
135 {
136 struct page *pg;
137 struct inode *inode = mapping->host;
138 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
139 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
140 pgoff_t index = pos >> PAGE_SHIFT;
141 uint32_t pageofs = index << PAGE_SHIFT;
142 int ret = 0;
143
144 jffs2_dbg(1, "%s()\n", __func__);
145
146 if (pageofs > inode->i_size) {
147 /* Make new hole frag from old EOF to new page */
148 struct jffs2_raw_inode ri;
149 struct jffs2_full_dnode *fn;
150 uint32_t alloc_len;
151
152 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
153 (unsigned int)inode->i_size, pageofs);
154
155 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
156 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
157 if (ret)
158 goto out_err;
159
160 mutex_lock(&f->sem);
161 memset(&ri, 0, sizeof(ri));
162
163 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
164 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
165 ri.totlen = cpu_to_je32(sizeof(ri));
166 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
167
168 ri.ino = cpu_to_je32(f->inocache->ino);
169 ri.version = cpu_to_je32(++f->highest_version);
170 ri.mode = cpu_to_jemode(inode->i_mode);
171 ri.uid = cpu_to_je16(i_uid_read(inode));
172 ri.gid = cpu_to_je16(i_gid_read(inode));
173 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
174 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW());
175 ri.offset = cpu_to_je32(inode->i_size);
176 ri.dsize = cpu_to_je32(pageofs - inode->i_size);
177 ri.csize = cpu_to_je32(0);
178 ri.compr = JFFS2_COMPR_ZERO;
179 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
180 ri.data_crc = cpu_to_je32(0);
181
182 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
183
184 if (IS_ERR(fn)) {
185 ret = PTR_ERR(fn);
186 jffs2_complete_reservation(c);
187 mutex_unlock(&f->sem);
188 goto out_err;
189 }
190 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
191 if (f->metadata) {
192 jffs2_mark_node_obsolete(c, f->metadata->raw);
193 jffs2_free_full_dnode(f->metadata);
194 f->metadata = NULL;
195 }
196 if (ret) {
197 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
198 ret);
199 jffs2_mark_node_obsolete(c, fn->raw);
200 jffs2_free_full_dnode(fn);
201 jffs2_complete_reservation(c);
202 mutex_unlock(&f->sem);
203 goto out_err;
204 }
205 jffs2_complete_reservation(c);
206 inode->i_size = pageofs;
207 mutex_unlock(&f->sem);
208 }
209
210 /*
211 * While getting a page and reading data in, lock c->alloc_sem until
212 * the page is Uptodate. Otherwise GC task may attempt to read the same
213 * page in read_cache_page(), which causes a deadlock.
214 */
215 mutex_lock(&c->alloc_sem);
216 pg = grab_cache_page_write_begin(mapping, index, flags);
217 if (!pg) {
218 ret = -ENOMEM;
219 goto release_sem;
220 }
221 *pagep = pg;
222
223 /*
224 * Read in the page if it wasn't already present. Cannot optimize away
225 * the whole page write case until jffs2_write_end can handle the
226 * case of a short-copy.
227 */
228 if (!PageUptodate(pg)) {
229 mutex_lock(&f->sem);
230 ret = jffs2_do_readpage_nolock(inode, pg);
231 mutex_unlock(&f->sem);
232 if (ret) {
233 unlock_page(pg);
234 put_page(pg);
235 goto release_sem;
236 }
237 }
238 jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
239
240 release_sem:
241 mutex_unlock(&c->alloc_sem);
242 out_err:
243 return ret;
244 }
245
jffs2_write_end(struct file * filp,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * pg,void * fsdata)246 static int jffs2_write_end(struct file *filp, struct address_space *mapping,
247 loff_t pos, unsigned len, unsigned copied,
248 struct page *pg, void *fsdata)
249 {
250 /* Actually commit the write from the page cache page we're looking at.
251 * For now, we write the full page out each time. It sucks, but it's simple
252 */
253 struct inode *inode = mapping->host;
254 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
255 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
256 struct jffs2_raw_inode *ri;
257 unsigned start = pos & (PAGE_SIZE - 1);
258 unsigned end = start + copied;
259 unsigned aligned_start = start & ~3;
260 int ret = 0;
261 uint32_t writtenlen = 0;
262
263 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
264 __func__, inode->i_ino, pg->index << PAGE_SHIFT,
265 start, end, pg->flags);
266
267 /* We need to avoid deadlock with page_cache_read() in
268 jffs2_garbage_collect_pass(). So the page must be
269 up to date to prevent page_cache_read() from trying
270 to re-lock it. */
271 BUG_ON(!PageUptodate(pg));
272
273 if (end == PAGE_SIZE) {
274 /* When writing out the end of a page, write out the
275 _whole_ page. This helps to reduce the number of
276 nodes in files which have many short writes, like
277 syslog files. */
278 aligned_start = 0;
279 }
280
281 ri = jffs2_alloc_raw_inode();
282
283 if (!ri) {
284 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
285 __func__);
286 unlock_page(pg);
287 put_page(pg);
288 return -ENOMEM;
289 }
290
291 /* Set the fields that the generic jffs2_write_inode_range() code can't find */
292 ri->ino = cpu_to_je32(inode->i_ino);
293 ri->mode = cpu_to_jemode(inode->i_mode);
294 ri->uid = cpu_to_je16(i_uid_read(inode));
295 ri->gid = cpu_to_je16(i_gid_read(inode));
296 ri->isize = cpu_to_je32((uint32_t)inode->i_size);
297 ri->atime = ri->ctime = ri->mtime = cpu_to_je32(JFFS2_NOW());
298
299 /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
300 hurt to do it again. The alternative is ifdefs, which are ugly. */
301 kmap(pg);
302
303 ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
304 (pg->index << PAGE_SHIFT) + aligned_start,
305 end - aligned_start, &writtenlen);
306
307 kunmap(pg);
308
309 if (ret) {
310 /* There was an error writing. */
311 SetPageError(pg);
312 }
313
314 /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
315 writtenlen -= min(writtenlen, (start - aligned_start));
316
317 if (writtenlen) {
318 if (inode->i_size < pos + writtenlen) {
319 inode->i_size = pos + writtenlen;
320 inode->i_blocks = (inode->i_size + 511) >> 9;
321
322 inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
323 }
324 }
325
326 jffs2_free_raw_inode(ri);
327
328 if (start+writtenlen < end) {
329 /* generic_file_write has written more to the page cache than we've
330 actually written to the medium. Mark the page !Uptodate so that
331 it gets reread */
332 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n",
333 __func__);
334 SetPageError(pg);
335 ClearPageUptodate(pg);
336 }
337
338 jffs2_dbg(1, "%s() returning %d\n",
339 __func__, writtenlen > 0 ? writtenlen : ret);
340 unlock_page(pg);
341 put_page(pg);
342 return writtenlen > 0 ? writtenlen : ret;
343 }
344