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
24static 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);
27static 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);
30static int jffs2_readpage (struct file *filp, struct page *pg);
31
32int 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	mutex_lock(&inode->i_mutex);
43	/* Trigger GC to flush any pending writes for this inode */
44	jffs2_flush_wbuf_gc(c, inode->i_ino);
45	mutex_unlock(&inode->i_mutex);
46
47	return 0;
48}
49
50const struct file_operations jffs2_file_operations =
51{
52	.llseek =	generic_file_llseek,
53	.open =		generic_file_open,
54 	.read =		new_sync_read,
55 	.read_iter =	generic_file_read_iter,
56 	.write =	new_sync_write,
57 	.write_iter =	generic_file_write_iter,
58	.unlocked_ioctl=jffs2_ioctl,
59	.mmap =		generic_file_readonly_mmap,
60	.fsync =	jffs2_fsync,
61	.splice_read =	generic_file_splice_read,
62};
63
64/* jffs2_file_inode_operations */
65
66const struct inode_operations jffs2_file_inode_operations =
67{
68	.get_acl =	jffs2_get_acl,
69	.set_acl =	jffs2_set_acl,
70	.setattr =	jffs2_setattr,
71	.setxattr =	jffs2_setxattr,
72	.getxattr =	jffs2_getxattr,
73	.listxattr =	jffs2_listxattr,
74	.removexattr =	jffs2_removexattr
75};
76
77const struct address_space_operations jffs2_file_address_operations =
78{
79	.readpage =	jffs2_readpage,
80	.write_begin =	jffs2_write_begin,
81	.write_end =	jffs2_write_end,
82};
83
84static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
85{
86	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
87	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
88	unsigned char *pg_buf;
89	int ret;
90
91	jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n",
92		  __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT);
93
94	BUG_ON(!PageLocked(pg));
95
96	pg_buf = kmap(pg);
97	/* FIXME: Can kmap fail? */
98
99	ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE);
100
101	if (ret) {
102		ClearPageUptodate(pg);
103		SetPageError(pg);
104	} else {
105		SetPageUptodate(pg);
106		ClearPageError(pg);
107	}
108
109	flush_dcache_page(pg);
110	kunmap(pg);
111
112	jffs2_dbg(2, "readpage finished\n");
113	return ret;
114}
115
116int jffs2_do_readpage_unlock(struct inode *inode, struct page *pg)
117{
118	int ret = jffs2_do_readpage_nolock(inode, pg);
119	unlock_page(pg);
120	return ret;
121}
122
123
124static int jffs2_readpage (struct file *filp, struct page *pg)
125{
126	struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
127	int ret;
128
129	mutex_lock(&f->sem);
130	ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
131	mutex_unlock(&f->sem);
132	return ret;
133}
134
135static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
136			loff_t pos, unsigned len, unsigned flags,
137			struct page **pagep, void **fsdata)
138{
139	struct page *pg;
140	struct inode *inode = mapping->host;
141	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
142	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
143	struct jffs2_raw_inode ri;
144	uint32_t alloc_len = 0;
145	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
146	uint32_t pageofs = index << PAGE_CACHE_SHIFT;
147	int ret = 0;
148
149	jffs2_dbg(1, "%s()\n", __func__);
150
151	if (pageofs > inode->i_size) {
152		ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
153					  ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
154		if (ret)
155			return ret;
156	}
157
158	mutex_lock(&f->sem);
159	pg = grab_cache_page_write_begin(mapping, index, flags);
160	if (!pg) {
161		if (alloc_len)
162			jffs2_complete_reservation(c);
163		mutex_unlock(&f->sem);
164		return -ENOMEM;
165	}
166	*pagep = pg;
167
168	if (alloc_len) {
169		/* Make new hole frag from old EOF to new page */
170		struct jffs2_full_dnode *fn;
171
172		jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
173			  (unsigned int)inode->i_size, pageofs);
174
175		memset(&ri, 0, sizeof(ri));
176
177		ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
178		ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
179		ri.totlen = cpu_to_je32(sizeof(ri));
180		ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
181
182		ri.ino = cpu_to_je32(f->inocache->ino);
183		ri.version = cpu_to_je32(++f->highest_version);
184		ri.mode = cpu_to_jemode(inode->i_mode);
185		ri.uid = cpu_to_je16(i_uid_read(inode));
186		ri.gid = cpu_to_je16(i_gid_read(inode));
187		ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
188		ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());
189		ri.offset = cpu_to_je32(inode->i_size);
190		ri.dsize = cpu_to_je32(pageofs - inode->i_size);
191		ri.csize = cpu_to_je32(0);
192		ri.compr = JFFS2_COMPR_ZERO;
193		ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
194		ri.data_crc = cpu_to_je32(0);
195
196		fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
197
198		if (IS_ERR(fn)) {
199			ret = PTR_ERR(fn);
200			jffs2_complete_reservation(c);
201			goto out_page;
202		}
203		ret = jffs2_add_full_dnode_to_inode(c, f, fn);
204		if (f->metadata) {
205			jffs2_mark_node_obsolete(c, f->metadata->raw);
206			jffs2_free_full_dnode(f->metadata);
207			f->metadata = NULL;
208		}
209		if (ret) {
210			jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
211				  ret);
212			jffs2_mark_node_obsolete(c, fn->raw);
213			jffs2_free_full_dnode(fn);
214			jffs2_complete_reservation(c);
215			goto out_page;
216		}
217		jffs2_complete_reservation(c);
218		inode->i_size = pageofs;
219	}
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		ret = jffs2_do_readpage_nolock(inode, pg);
228		if (ret)
229			goto out_page;
230	}
231	mutex_unlock(&f->sem);
232	jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
233	return ret;
234
235out_page:
236	unlock_page(pg);
237	page_cache_release(pg);
238	mutex_unlock(&f->sem);
239	return ret;
240}
241
242static int jffs2_write_end(struct file *filp, struct address_space *mapping,
243			loff_t pos, unsigned len, unsigned copied,
244			struct page *pg, void *fsdata)
245{
246	/* Actually commit the write from the page cache page we're looking at.
247	 * For now, we write the full page out each time. It sucks, but it's simple
248	 */
249	struct inode *inode = mapping->host;
250	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
251	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
252	struct jffs2_raw_inode *ri;
253	unsigned start = pos & (PAGE_CACHE_SIZE - 1);
254	unsigned end = start + copied;
255	unsigned aligned_start = start & ~3;
256	int ret = 0;
257	uint32_t writtenlen = 0;
258
259	jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
260		  __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT,
261		  start, end, pg->flags);
262
263	/* We need to avoid deadlock with page_cache_read() in
264	   jffs2_garbage_collect_pass(). So the page must be
265	   up to date to prevent page_cache_read() from trying
266	   to re-lock it. */
267	BUG_ON(!PageUptodate(pg));
268
269	if (end == PAGE_CACHE_SIZE) {
270		/* When writing out the end of a page, write out the
271		   _whole_ page. This helps to reduce the number of
272		   nodes in files which have many short writes, like
273		   syslog files. */
274		aligned_start = 0;
275	}
276
277	ri = jffs2_alloc_raw_inode();
278
279	if (!ri) {
280		jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
281			  __func__);
282		unlock_page(pg);
283		page_cache_release(pg);
284		return -ENOMEM;
285	}
286
287	/* Set the fields that the generic jffs2_write_inode_range() code can't find */
288	ri->ino = cpu_to_je32(inode->i_ino);
289	ri->mode = cpu_to_jemode(inode->i_mode);
290	ri->uid = cpu_to_je16(i_uid_read(inode));
291	ri->gid = cpu_to_je16(i_gid_read(inode));
292	ri->isize = cpu_to_je32((uint32_t)inode->i_size);
293	ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds());
294
295	/* In 2.4, it was already kmapped by generic_file_write(). Doesn't
296	   hurt to do it again. The alternative is ifdefs, which are ugly. */
297	kmap(pg);
298
299	ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
300				      (pg->index << PAGE_CACHE_SHIFT) + aligned_start,
301				      end - aligned_start, &writtenlen);
302
303	kunmap(pg);
304
305	if (ret) {
306		/* There was an error writing. */
307		SetPageError(pg);
308	}
309
310	/* Adjust writtenlen for the padding we did, so we don't confuse our caller */
311	writtenlen -= min(writtenlen, (start - aligned_start));
312
313	if (writtenlen) {
314		if (inode->i_size < pos + writtenlen) {
315			inode->i_size = pos + writtenlen;
316			inode->i_blocks = (inode->i_size + 511) >> 9;
317
318			inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
319		}
320	}
321
322	jffs2_free_raw_inode(ri);
323
324	if (start+writtenlen < end) {
325		/* generic_file_write has written more to the page cache than we've
326		   actually written to the medium. Mark the page !Uptodate so that
327		   it gets reread */
328		jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n",
329			__func__);
330		SetPageError(pg);
331		ClearPageUptodate(pg);
332	}
333
334	jffs2_dbg(1, "%s() returning %d\n",
335		  __func__, writtenlen > 0 ? writtenlen : ret);
336	unlock_page(pg);
337	page_cache_release(pg);
338	return writtenlen > 0 ? writtenlen : ret;
339}
340