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