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,
29			struct page **pagep, void **fsdata);
30static int jffs2_read_folio(struct file *filp, struct folio *folio);
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 = 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
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 =	filemap_splice_read,
60	.splice_write = iter_file_splice_write,
61};
62
63/* jffs2_file_inode_operations */
64
65const 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
73const 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
80static 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
113int __jffs2_read_folio(struct file *file, struct folio *folio)
114{
115	int ret = jffs2_do_readpage_nolock(folio->mapping->host, &folio->page);
116	folio_unlock(folio);
117	return ret;
118}
119
120static int jffs2_read_folio(struct file *file, struct folio *folio)
121{
122	struct jffs2_inode_info *f = JFFS2_INODE_INFO(folio->mapping->host);
123	int ret;
124
125	mutex_lock(&f->sem);
126	ret = __jffs2_read_folio(file, folio);
127	mutex_unlock(&f->sem);
128	return ret;
129}
130
131static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
132			loff_t pos, unsigned len,
133			struct page **pagep, void **fsdata)
134{
135	struct page *pg;
136	struct inode *inode = mapping->host;
137	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
138	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
139	pgoff_t index = pos >> PAGE_SHIFT;
140	int ret = 0;
141
142	jffs2_dbg(1, "%s()\n", __func__);
143
144	if (pos > inode->i_size) {
145		/* Make new hole frag from old EOF to new position */
146		struct jffs2_raw_inode ri;
147		struct jffs2_full_dnode *fn;
148		uint32_t alloc_len;
149
150		jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new position\n",
151			  (unsigned int)inode->i_size, (uint32_t)pos);
152
153		ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
154					  ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
155		if (ret)
156			goto out_err;
157
158		mutex_lock(&f->sem);
159		memset(&ri, 0, sizeof(ri));
160
161		ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
162		ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
163		ri.totlen = cpu_to_je32(sizeof(ri));
164		ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
165
166		ri.ino = cpu_to_je32(f->inocache->ino);
167		ri.version = cpu_to_je32(++f->highest_version);
168		ri.mode = cpu_to_jemode(inode->i_mode);
169		ri.uid = cpu_to_je16(i_uid_read(inode));
170		ri.gid = cpu_to_je16(i_gid_read(inode));
171		ri.isize = cpu_to_je32((uint32_t)pos);
172		ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW());
173		ri.offset = cpu_to_je32(inode->i_size);
174		ri.dsize = cpu_to_je32((uint32_t)pos - inode->i_size);
175		ri.csize = cpu_to_je32(0);
176		ri.compr = JFFS2_COMPR_ZERO;
177		ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
178		ri.data_crc = cpu_to_je32(0);
179
180		fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
181
182		if (IS_ERR(fn)) {
183			ret = PTR_ERR(fn);
184			jffs2_complete_reservation(c);
185			mutex_unlock(&f->sem);
186			goto out_err;
187		}
188		ret = jffs2_add_full_dnode_to_inode(c, f, fn);
189		if (f->metadata) {
190			jffs2_mark_node_obsolete(c, f->metadata->raw);
191			jffs2_free_full_dnode(f->metadata);
192			f->metadata = NULL;
193		}
194		if (ret) {
195			jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
196				  ret);
197			jffs2_mark_node_obsolete(c, fn->raw);
198			jffs2_free_full_dnode(fn);
199			jffs2_complete_reservation(c);
200			mutex_unlock(&f->sem);
201			goto out_err;
202		}
203		jffs2_complete_reservation(c);
204		inode->i_size = pos;
205		mutex_unlock(&f->sem);
206	}
207
208	/*
209	 * While getting a page and reading data in, lock c->alloc_sem until
210	 * the page is Uptodate. Otherwise GC task may attempt to read the same
211	 * page in read_cache_page(), which causes a deadlock.
212	 */
213	mutex_lock(&c->alloc_sem);
214	pg = grab_cache_page_write_begin(mapping, index);
215	if (!pg) {
216		ret = -ENOMEM;
217		goto release_sem;
218	}
219	*pagep = pg;
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		mutex_lock(&f->sem);
228		ret = jffs2_do_readpage_nolock(inode, pg);
229		mutex_unlock(&f->sem);
230		if (ret) {
231			unlock_page(pg);
232			put_page(pg);
233			goto release_sem;
234		}
235	}
236	jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
237
238release_sem:
239	mutex_unlock(&c->alloc_sem);
240out_err:
241	return ret;
242}
243
244static int jffs2_write_end(struct file *filp, struct address_space *mapping,
245			loff_t pos, unsigned len, unsigned copied,
246			struct page *pg, void *fsdata)
247{
248	/* Actually commit the write from the page cache page we're looking at.
249	 * For now, we write the full page out each time. It sucks, but it's simple
250	 */
251	struct inode *inode = mapping->host;
252	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
253	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
254	struct jffs2_raw_inode *ri;
255	unsigned start = pos & (PAGE_SIZE - 1);
256	unsigned end = start + copied;
257	unsigned aligned_start = start & ~3;
258	int ret = 0;
259	uint32_t writtenlen = 0;
260
261	jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
262		  __func__, inode->i_ino, pg->index << PAGE_SHIFT,
263		  start, end, pg->flags);
264
265	/* We need to avoid deadlock with page_cache_read() in
266	   jffs2_garbage_collect_pass(). So the page must be
267	   up to date to prevent page_cache_read() from trying
268	   to re-lock it. */
269	BUG_ON(!PageUptodate(pg));
270
271	if (end == PAGE_SIZE) {
272		/* When writing out the end of a page, write out the
273		   _whole_ page. This helps to reduce the number of
274		   nodes in files which have many short writes, like
275		   syslog files. */
276		aligned_start = 0;
277	}
278
279	ri = jffs2_alloc_raw_inode();
280
281	if (!ri) {
282		jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
283			  __func__);
284		unlock_page(pg);
285		put_page(pg);
286		return -ENOMEM;
287	}
288
289	/* Set the fields that the generic jffs2_write_inode_range() code can't find */
290	ri->ino = cpu_to_je32(inode->i_ino);
291	ri->mode = cpu_to_jemode(inode->i_mode);
292	ri->uid = cpu_to_je16(i_uid_read(inode));
293	ri->gid = cpu_to_je16(i_gid_read(inode));
294	ri->isize = cpu_to_je32((uint32_t)inode->i_size);
295	ri->atime = ri->ctime = ri->mtime = cpu_to_je32(JFFS2_NOW());
296
297	/* In 2.4, it was already kmapped by generic_file_write(). Doesn't
298	   hurt to do it again. The alternative is ifdefs, which are ugly. */
299	kmap(pg);
300
301	ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
302				      (pg->index << PAGE_SHIFT) + aligned_start,
303				      end - aligned_start, &writtenlen);
304
305	kunmap(pg);
306
307	if (ret) {
308		/* There was an error writing. */
309		SetPageError(pg);
310	}
311
312	/* Adjust writtenlen for the padding we did, so we don't confuse our caller */
313	writtenlen -= min(writtenlen, (start - aligned_start));
314
315	if (writtenlen) {
316		if (inode->i_size < pos + writtenlen) {
317			inode->i_size = pos + writtenlen;
318			inode->i_blocks = (inode->i_size + 511) >> 9;
319
320			inode_set_mtime_to_ts(inode,
321					      inode_set_ctime_to_ts(inode, ITIME(je32_to_cpu(ri->ctime))));
322		}
323	}
324
325	jffs2_free_raw_inode(ri);
326
327	if (start+writtenlen < end) {
328		/* generic_file_write has written more to the page cache than we've
329		   actually written to the medium. Mark the page !Uptodate so that
330		   it gets reread */
331		jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n",
332			__func__);
333		SetPageError(pg);
334		ClearPageUptodate(pg);
335	}
336
337	jffs2_dbg(1, "%s() returning %d\n",
338		  __func__, writtenlen > 0 ? writtenlen : ret);
339	unlock_page(pg);
340	put_page(pg);
341	return writtenlen > 0 ? writtenlen : ret;
342}
343