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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
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 = filemap_write_and_wait_range(inode->i_mapping, 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 };
61
62 /* jffs2_file_inode_operations */
63
64 const struct inode_operations jffs2_file_inode_operations =
65 {
66 .get_acl = jffs2_get_acl,
67 .set_acl = jffs2_set_acl,
68 .setattr = jffs2_setattr,
69 .setxattr = jffs2_setxattr,
70 .getxattr = jffs2_getxattr,
71 .listxattr = jffs2_listxattr,
72 .removexattr = jffs2_removexattr
73 };
74
75 const struct address_space_operations jffs2_file_address_operations =
76 {
77 .readpage = jffs2_readpage,
78 .write_begin = jffs2_write_begin,
79 .write_end = jffs2_write_end,
80 };
81
82 static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
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 *pg_buf;
87 int ret;
88
89 jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n",
90 __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT);
91
92 BUG_ON(!PageLocked(pg));
93
94 pg_buf = kmap(pg);
95 /* FIXME: Can kmap fail? */
96
97 ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE);
98
99 if (ret) {
100 ClearPageUptodate(pg);
101 SetPageError(pg);
102 } else {
103 SetPageUptodate(pg);
104 ClearPageError(pg);
105 }
106
107 flush_dcache_page(pg);
108 kunmap(pg);
109
110 jffs2_dbg(2, "readpage finished\n");
111 return ret;
112 }
113
114 int jffs2_do_readpage_unlock(struct inode *inode, struct page *pg)
115 {
116 int ret = jffs2_do_readpage_nolock(inode, pg);
117 unlock_page(pg);
118 return ret;
119 }
120
121
122 static int jffs2_readpage (struct file *filp, struct page *pg)
123 {
124 struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
125 int ret;
126
127 mutex_lock(&f->sem);
128 ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
129 mutex_unlock(&f->sem);
130 return ret;
131 }
132
133 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
134 loff_t pos, unsigned len, unsigned flags,
135 struct page **pagep, void **fsdata)
136 {
137 struct page *pg;
138 struct inode *inode = mapping->host;
139 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
140 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
141 struct jffs2_raw_inode ri;
142 uint32_t alloc_len = 0;
143 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
144 uint32_t pageofs = index << PAGE_CACHE_SHIFT;
145 int ret = 0;
146
147 jffs2_dbg(1, "%s()\n", __func__);
148
149 if (pageofs > inode->i_size) {
150 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
151 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
152 if (ret)
153 return ret;
154 }
155
156 mutex_lock(&f->sem);
157 pg = grab_cache_page_write_begin(mapping, index, flags);
158 if (!pg) {
159 if (alloc_len)
160 jffs2_complete_reservation(c);
161 mutex_unlock(&f->sem);
162 return -ENOMEM;
163 }
164 *pagep = pg;
165
166 if (alloc_len) {
167 /* Make new hole frag from old EOF to new page */
168 struct jffs2_full_dnode *fn;
169
170 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
171 (unsigned int)inode->i_size, pageofs);
172
173 memset(&ri, 0, sizeof(ri));
174
175 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
176 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
177 ri.totlen = cpu_to_je32(sizeof(ri));
178 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
179
180 ri.ino = cpu_to_je32(f->inocache->ino);
181 ri.version = cpu_to_je32(++f->highest_version);
182 ri.mode = cpu_to_jemode(inode->i_mode);
183 ri.uid = cpu_to_je16(i_uid_read(inode));
184 ri.gid = cpu_to_je16(i_gid_read(inode));
185 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
186 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());
187 ri.offset = cpu_to_je32(inode->i_size);
188 ri.dsize = cpu_to_je32(pageofs - inode->i_size);
189 ri.csize = cpu_to_je32(0);
190 ri.compr = JFFS2_COMPR_ZERO;
191 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
192 ri.data_crc = cpu_to_je32(0);
193
194 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
195
196 if (IS_ERR(fn)) {
197 ret = PTR_ERR(fn);
198 jffs2_complete_reservation(c);
199 goto out_page;
200 }
201 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
202 if (f->metadata) {
203 jffs2_mark_node_obsolete(c, f->metadata->raw);
204 jffs2_free_full_dnode(f->metadata);
205 f->metadata = NULL;
206 }
207 if (ret) {
208 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
209 ret);
210 jffs2_mark_node_obsolete(c, fn->raw);
211 jffs2_free_full_dnode(fn);
212 jffs2_complete_reservation(c);
213 goto out_page;
214 }
215 jffs2_complete_reservation(c);
216 inode->i_size = pageofs;
217 }
218
219 /*
220 * Read in the page if it wasn't already present. Cannot optimize away
221 * the whole page write case until jffs2_write_end can handle the
222 * case of a short-copy.
223 */
224 if (!PageUptodate(pg)) {
225 ret = jffs2_do_readpage_nolock(inode, pg);
226 if (ret)
227 goto out_page;
228 }
229 mutex_unlock(&f->sem);
230 jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
231 return ret;
232
233 out_page:
234 unlock_page(pg);
235 page_cache_release(pg);
236 mutex_unlock(&f->sem);
237 return ret;
238 }
239
240 static int jffs2_write_end(struct file *filp, struct address_space *mapping,
241 loff_t pos, unsigned len, unsigned copied,
242 struct page *pg, void *fsdata)
243 {
244 /* Actually commit the write from the page cache page we're looking at.
245 * For now, we write the full page out each time. It sucks, but it's simple
246 */
247 struct inode *inode = mapping->host;
248 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
249 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
250 struct jffs2_raw_inode *ri;
251 unsigned start = pos & (PAGE_CACHE_SIZE - 1);
252 unsigned end = start + copied;
253 unsigned aligned_start = start & ~3;
254 int ret = 0;
255 uint32_t writtenlen = 0;
256
257 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
258 __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT,
259 start, end, pg->flags);
260
261 /* We need to avoid deadlock with page_cache_read() in
262 jffs2_garbage_collect_pass(). So the page must be
263 up to date to prevent page_cache_read() from trying
264 to re-lock it. */
265 BUG_ON(!PageUptodate(pg));
266
267 if (end == PAGE_CACHE_SIZE) {
268 /* When writing out the end of a page, write out the
269 _whole_ page. This helps to reduce the number of
270 nodes in files which have many short writes, like
271 syslog files. */
272 aligned_start = 0;
273 }
274
275 ri = jffs2_alloc_raw_inode();
276
277 if (!ri) {
278 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
279 __func__);
280 unlock_page(pg);
281 page_cache_release(pg);
282 return -ENOMEM;
283 }
284
285 /* Set the fields that the generic jffs2_write_inode_range() code can't find */
286 ri->ino = cpu_to_je32(inode->i_ino);
287 ri->mode = cpu_to_jemode(inode->i_mode);
288 ri->uid = cpu_to_je16(i_uid_read(inode));
289 ri->gid = cpu_to_je16(i_gid_read(inode));
290 ri->isize = cpu_to_je32((uint32_t)inode->i_size);
291 ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds());
292
293 /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
294 hurt to do it again. The alternative is ifdefs, which are ugly. */
295 kmap(pg);
296
297 ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
298 (pg->index << PAGE_CACHE_SHIFT) + aligned_start,
299 end - aligned_start, &writtenlen);
300
301 kunmap(pg);
302
303 if (ret) {
304 /* There was an error writing. */
305 SetPageError(pg);
306 }
307
308 /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
309 writtenlen -= min(writtenlen, (start - aligned_start));
310
311 if (writtenlen) {
312 if (inode->i_size < pos + writtenlen) {
313 inode->i_size = pos + writtenlen;
314 inode->i_blocks = (inode->i_size + 511) >> 9;
315
316 inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
317 }
318 }
319
320 jffs2_free_raw_inode(ri);
321
322 if (start+writtenlen < end) {
323 /* generic_file_write has written more to the page cache than we've
324 actually written to the medium. Mark the page !Uptodate so that
325 it gets reread */
326 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n",
327 __func__);
328 SetPageError(pg);
329 ClearPageUptodate(pg);
330 }
331
332 jffs2_dbg(1, "%s() returning %d\n",
333 __func__, writtenlen > 0 ? writtenlen : ret);
334 unlock_page(pg);
335 page_cache_release(pg);
336 return writtenlen > 0 ? writtenlen : ret;
337 }