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 folio *folio, void *fsdata);
27 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
28 loff_t pos, unsigned len,
29 struct folio **foliop, 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 folio * folio)80 static int jffs2_do_readpage_nolock(struct inode *inode, struct folio *folio)
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 *kaddr;
85 int ret;
86
87 jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n",
88 __func__, inode->i_ino, folio->index << PAGE_SHIFT);
89
90 BUG_ON(!folio_test_locked(folio));
91
92 kaddr = kmap_local_folio(folio, 0);
93 ret = jffs2_read_inode_range(c, f, kaddr, folio->index << PAGE_SHIFT,
94 PAGE_SIZE);
95 kunmap_local(kaddr);
96
97 if (!ret)
98 folio_mark_uptodate(folio);
99
100 flush_dcache_folio(folio);
101
102 jffs2_dbg(2, "readpage finished\n");
103 return ret;
104 }
105
__jffs2_read_folio(struct file * file,struct folio * folio)106 int __jffs2_read_folio(struct file *file, struct folio *folio)
107 {
108 int ret = jffs2_do_readpage_nolock(folio->mapping->host, folio);
109 folio_unlock(folio);
110 return ret;
111 }
112
jffs2_read_folio(struct file * file,struct folio * folio)113 static int jffs2_read_folio(struct file *file, struct folio *folio)
114 {
115 struct jffs2_inode_info *f = JFFS2_INODE_INFO(folio->mapping->host);
116 int ret;
117
118 mutex_lock(&f->sem);
119 ret = __jffs2_read_folio(file, folio);
120 mutex_unlock(&f->sem);
121 return ret;
122 }
123
jffs2_write_begin(struct file * filp,struct address_space * mapping,loff_t pos,unsigned len,struct folio ** foliop,void ** fsdata)124 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
125 loff_t pos, unsigned len,
126 struct folio **foliop, void **fsdata)
127 {
128 struct folio *folio;
129 struct inode *inode = mapping->host;
130 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
131 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
132 pgoff_t index = pos >> PAGE_SHIFT;
133 int ret = 0;
134
135 jffs2_dbg(1, "%s()\n", __func__);
136
137 if (pos > inode->i_size) {
138 /* Make new hole frag from old EOF to new position */
139 struct jffs2_raw_inode ri;
140 struct jffs2_full_dnode *fn;
141 uint32_t alloc_len;
142
143 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new position\n",
144 (unsigned int)inode->i_size, (uint32_t)pos);
145
146 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
147 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
148 if (ret)
149 goto out_err;
150
151 mutex_lock(&f->sem);
152 memset(&ri, 0, sizeof(ri));
153
154 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
155 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
156 ri.totlen = cpu_to_je32(sizeof(ri));
157 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
158
159 ri.ino = cpu_to_je32(f->inocache->ino);
160 ri.version = cpu_to_je32(++f->highest_version);
161 ri.mode = cpu_to_jemode(inode->i_mode);
162 ri.uid = cpu_to_je16(i_uid_read(inode));
163 ri.gid = cpu_to_je16(i_gid_read(inode));
164 ri.isize = cpu_to_je32((uint32_t)pos);
165 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW());
166 ri.offset = cpu_to_je32(inode->i_size);
167 ri.dsize = cpu_to_je32((uint32_t)pos - inode->i_size);
168 ri.csize = cpu_to_je32(0);
169 ri.compr = JFFS2_COMPR_ZERO;
170 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
171 ri.data_crc = cpu_to_je32(0);
172
173 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
174
175 if (IS_ERR(fn)) {
176 ret = PTR_ERR(fn);
177 jffs2_complete_reservation(c);
178 mutex_unlock(&f->sem);
179 goto out_err;
180 }
181 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
182 if (f->metadata) {
183 jffs2_mark_node_obsolete(c, f->metadata->raw);
184 jffs2_free_full_dnode(f->metadata);
185 f->metadata = NULL;
186 }
187 if (ret) {
188 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
189 ret);
190 jffs2_mark_node_obsolete(c, fn->raw);
191 jffs2_free_full_dnode(fn);
192 jffs2_complete_reservation(c);
193 mutex_unlock(&f->sem);
194 goto out_err;
195 }
196 jffs2_complete_reservation(c);
197 inode->i_size = pos;
198 mutex_unlock(&f->sem);
199 }
200
201 /*
202 * While getting a page and reading data in, lock c->alloc_sem until
203 * the page is Uptodate. Otherwise GC task may attempt to read the same
204 * page in read_cache_page(), which causes a deadlock.
205 */
206 mutex_lock(&c->alloc_sem);
207 folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
208 mapping_gfp_mask(mapping));
209 if (IS_ERR(folio)) {
210 ret = PTR_ERR(folio);
211 goto release_sem;
212 }
213 *foliop = folio;
214
215 /*
216 * Read in the folio if it wasn't already present. Cannot optimize away
217 * the whole folio write case until jffs2_write_end can handle the
218 * case of a short-copy.
219 */
220 if (!folio_test_uptodate(folio)) {
221 mutex_lock(&f->sem);
222 ret = jffs2_do_readpage_nolock(inode, folio);
223 mutex_unlock(&f->sem);
224 if (ret) {
225 folio_unlock(folio);
226 folio_put(folio);
227 goto release_sem;
228 }
229 }
230 jffs2_dbg(1, "end write_begin(). folio->flags %lx\n", folio->flags);
231
232 release_sem:
233 mutex_unlock(&c->alloc_sem);
234 out_err:
235 return ret;
236 }
237
jffs2_write_end(struct file * filp,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct folio * folio,void * fsdata)238 static int jffs2_write_end(struct file *filp, struct address_space *mapping,
239 loff_t pos, unsigned len, unsigned copied,
240 struct folio *folio, void *fsdata)
241 {
242 /* Actually commit the write from the page cache page we're looking at.
243 * For now, we write the full page out each time. It sucks, but it's simple
244 */
245 struct inode *inode = mapping->host;
246 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
247 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
248 struct jffs2_raw_inode *ri;
249 unsigned start = pos & (PAGE_SIZE - 1);
250 unsigned end = start + copied;
251 unsigned aligned_start = start & ~3;
252 int ret = 0;
253 uint32_t writtenlen = 0;
254 void *buf;
255
256 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%llx, range %d-%d, flags %lx\n",
257 __func__, inode->i_ino, folio_pos(folio),
258 start, end, folio->flags);
259
260 /* We need to avoid deadlock with page_cache_read() in
261 jffs2_garbage_collect_pass(). So the folio must be
262 up to date to prevent page_cache_read() from trying
263 to re-lock it. */
264 BUG_ON(!folio_test_uptodate(folio));
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 folio_unlock(folio);
280 folio_put(folio);
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 buf = kmap_local_folio(folio, aligned_start);
293 ret = jffs2_write_inode_range(c, f, ri, buf,
294 folio_pos(folio) + aligned_start,
295 end - aligned_start, &writtenlen);
296 kunmap_local(buf);
297
298 if (ret)
299 mapping_set_error(mapping, ret);
300
301 /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
302 writtenlen -= min(writtenlen, (start - aligned_start));
303
304 if (writtenlen) {
305 if (inode->i_size < pos + writtenlen) {
306 inode->i_size = pos + writtenlen;
307 inode->i_blocks = (inode->i_size + 511) >> 9;
308
309 inode_set_mtime_to_ts(inode,
310 inode_set_ctime_to_ts(inode, ITIME(je32_to_cpu(ri->ctime))));
311 }
312 }
313
314 jffs2_free_raw_inode(ri);
315
316 if (start+writtenlen < end) {
317 /* generic_file_write has written more to the page cache than we've
318 actually written to the medium. Mark the page !Uptodate so that
319 it gets reread */
320 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n",
321 __func__);
322 folio_clear_uptodate(folio);
323 }
324
325 jffs2_dbg(1, "%s() returning %d\n",
326 __func__, writtenlen > 0 ? writtenlen : ret);
327 folio_unlock(folio);
328 folio_put(folio);
329 return writtenlen > 0 ? writtenlen : ret;
330 }
331