• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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 
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 = 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 
50 const struct file_operations jffs2_file_operations =
51 {
52 	.llseek =	generic_file_llseek,
53 	.open =		generic_file_open,
54  	.read =		do_sync_read,
55  	.aio_read =	generic_file_aio_read,
56  	.write =	do_sync_write,
57  	.aio_write =	generic_file_aio_write,
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 
66 const struct inode_operations jffs2_file_inode_operations =
67 {
68 	.get_acl =	jffs2_get_acl,
69 	.setattr =	jffs2_setattr,
70 	.setxattr =	jffs2_setxattr,
71 	.getxattr =	jffs2_getxattr,
72 	.listxattr =	jffs2_listxattr,
73 	.removexattr =	jffs2_removexattr
74 };
75 
76 const struct address_space_operations jffs2_file_address_operations =
77 {
78 	.readpage =	jffs2_readpage,
79 	.write_begin =	jffs2_write_begin,
80 	.write_end =	jffs2_write_end,
81 };
82 
jffs2_do_readpage_nolock(struct inode * inode,struct page * pg)83 static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
84 {
85 	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
86 	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
87 	unsigned char *pg_buf;
88 	int ret;
89 
90 	jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n",
91 		  __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT);
92 
93 	BUG_ON(!PageLocked(pg));
94 
95 	pg_buf = kmap(pg);
96 	/* FIXME: Can kmap fail? */
97 
98 	ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE);
99 
100 	if (ret) {
101 		ClearPageUptodate(pg);
102 		SetPageError(pg);
103 	} else {
104 		SetPageUptodate(pg);
105 		ClearPageError(pg);
106 	}
107 
108 	flush_dcache_page(pg);
109 	kunmap(pg);
110 
111 	jffs2_dbg(2, "readpage finished\n");
112 	return ret;
113 }
114 
jffs2_do_readpage_unlock(struct inode * inode,struct page * pg)115 int jffs2_do_readpage_unlock(struct inode *inode, struct page *pg)
116 {
117 	int ret = jffs2_do_readpage_nolock(inode, pg);
118 	unlock_page(pg);
119 	return ret;
120 }
121 
122 
jffs2_readpage(struct file * filp,struct page * pg)123 static int jffs2_readpage (struct file *filp, struct page *pg)
124 {
125 	struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
126 	int ret;
127 
128 	mutex_lock(&f->sem);
129 	ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
130 	mutex_unlock(&f->sem);
131 	return ret;
132 }
133 
jffs2_write_begin(struct file * filp,struct address_space * mapping,loff_t pos,unsigned len,unsigned flags,struct page ** pagep,void ** fsdata)134 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
135 			loff_t pos, unsigned len, unsigned flags,
136 			struct page **pagep, void **fsdata)
137 {
138 	struct page *pg;
139 	struct inode *inode = mapping->host;
140 	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
141 	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
142 	struct jffs2_raw_inode ri;
143 	uint32_t alloc_len = 0;
144 	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
145 	uint32_t pageofs = index << PAGE_CACHE_SHIFT;
146 	int ret = 0;
147 
148 	jffs2_dbg(1, "%s()\n", __func__);
149 
150 	if (pageofs > inode->i_size) {
151 		ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
152 					  ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
153 		if (ret)
154 			return ret;
155 	}
156 
157 	mutex_lock(&f->sem);
158 	pg = grab_cache_page_write_begin(mapping, index, flags);
159 	if (!pg) {
160 		if (alloc_len)
161 			jffs2_complete_reservation(c);
162 		mutex_unlock(&f->sem);
163 		return -ENOMEM;
164 	}
165 	*pagep = pg;
166 
167 	if (alloc_len) {
168 		/* Make new hole frag from old EOF to new page */
169 		struct jffs2_full_dnode *fn;
170 
171 		jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
172 			  (unsigned int)inode->i_size, pageofs);
173 
174 		memset(&ri, 0, sizeof(ri));
175 
176 		ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
177 		ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
178 		ri.totlen = cpu_to_je32(sizeof(ri));
179 		ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
180 
181 		ri.ino = cpu_to_je32(f->inocache->ino);
182 		ri.version = cpu_to_je32(++f->highest_version);
183 		ri.mode = cpu_to_jemode(inode->i_mode);
184 		ri.uid = cpu_to_je16(inode->i_uid);
185 		ri.gid = cpu_to_je16(inode->i_gid);
186 		ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
187 		ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());
188 		ri.offset = cpu_to_je32(inode->i_size);
189 		ri.dsize = cpu_to_je32(pageofs - inode->i_size);
190 		ri.csize = cpu_to_je32(0);
191 		ri.compr = JFFS2_COMPR_ZERO;
192 		ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
193 		ri.data_crc = cpu_to_je32(0);
194 
195 		fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
196 
197 		if (IS_ERR(fn)) {
198 			ret = PTR_ERR(fn);
199 			jffs2_complete_reservation(c);
200 			goto out_page;
201 		}
202 		ret = jffs2_add_full_dnode_to_inode(c, f, fn);
203 		if (f->metadata) {
204 			jffs2_mark_node_obsolete(c, f->metadata->raw);
205 			jffs2_free_full_dnode(f->metadata);
206 			f->metadata = NULL;
207 		}
208 		if (ret) {
209 			jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
210 				  ret);
211 			jffs2_mark_node_obsolete(c, fn->raw);
212 			jffs2_free_full_dnode(fn);
213 			jffs2_complete_reservation(c);
214 			goto out_page;
215 		}
216 		jffs2_complete_reservation(c);
217 		inode->i_size = pageofs;
218 	}
219 
220 	/*
221 	 * Read in the page if it wasn't already present. Cannot optimize away
222 	 * the whole page write case until jffs2_write_end can handle the
223 	 * case of a short-copy.
224 	 */
225 	if (!PageUptodate(pg)) {
226 		ret = jffs2_do_readpage_nolock(inode, pg);
227 		if (ret)
228 			goto out_page;
229 	}
230 	mutex_unlock(&f->sem);
231 	jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
232 	return ret;
233 
234 out_page:
235 	unlock_page(pg);
236 	page_cache_release(pg);
237 	mutex_unlock(&f->sem);
238 	return ret;
239 }
240 
jffs2_write_end(struct file * filp,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * pg,void * fsdata)241 static int jffs2_write_end(struct file *filp, struct address_space *mapping,
242 			loff_t pos, unsigned len, unsigned copied,
243 			struct page *pg, void *fsdata)
244 {
245 	/* Actually commit the write from the page cache page we're looking at.
246 	 * For now, we write the full page out each time. It sucks, but it's simple
247 	 */
248 	struct inode *inode = mapping->host;
249 	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
250 	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
251 	struct jffs2_raw_inode *ri;
252 	unsigned start = pos & (PAGE_CACHE_SIZE - 1);
253 	unsigned end = start + copied;
254 	unsigned aligned_start = start & ~3;
255 	int ret = 0;
256 	uint32_t writtenlen = 0;
257 
258 	jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
259 		  __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT,
260 		  start, end, pg->flags);
261 
262 	/* We need to avoid deadlock with page_cache_read() in
263 	   jffs2_garbage_collect_pass(). So the page must be
264 	   up to date to prevent page_cache_read() from trying
265 	   to re-lock it. */
266 	BUG_ON(!PageUptodate(pg));
267 
268 	if (end == PAGE_CACHE_SIZE) {
269 		/* When writing out the end of a page, write out the
270 		   _whole_ page. This helps to reduce the number of
271 		   nodes in files which have many short writes, like
272 		   syslog files. */
273 		aligned_start = 0;
274 	}
275 
276 	ri = jffs2_alloc_raw_inode();
277 
278 	if (!ri) {
279 		jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
280 			  __func__);
281 		unlock_page(pg);
282 		page_cache_release(pg);
283 		return -ENOMEM;
284 	}
285 
286 	/* Set the fields that the generic jffs2_write_inode_range() code can't find */
287 	ri->ino = cpu_to_je32(inode->i_ino);
288 	ri->mode = cpu_to_jemode(inode->i_mode);
289 	ri->uid = cpu_to_je16(inode->i_uid);
290 	ri->gid = cpu_to_je16(inode->i_gid);
291 	ri->isize = cpu_to_je32((uint32_t)inode->i_size);
292 	ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds());
293 
294 	/* In 2.4, it was already kmapped by generic_file_write(). Doesn't
295 	   hurt to do it again. The alternative is ifdefs, which are ugly. */
296 	kmap(pg);
297 
298 	ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
299 				      (pg->index << PAGE_CACHE_SHIFT) + aligned_start,
300 				      end - aligned_start, &writtenlen);
301 
302 	kunmap(pg);
303 
304 	if (ret) {
305 		/* There was an error writing. */
306 		SetPageError(pg);
307 	}
308 
309 	/* Adjust writtenlen for the padding we did, so we don't confuse our caller */
310 	writtenlen -= min(writtenlen, (start - aligned_start));
311 
312 	if (writtenlen) {
313 		if (inode->i_size < pos + writtenlen) {
314 			inode->i_size = pos + writtenlen;
315 			inode->i_blocks = (inode->i_size + 511) >> 9;
316 
317 			inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
318 		}
319 	}
320 
321 	jffs2_free_raw_inode(ri);
322 
323 	if (start+writtenlen < end) {
324 		/* generic_file_write has written more to the page cache than we've
325 		   actually written to the medium. Mark the page !Uptodate so that
326 		   it gets reread */
327 		jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n",
328 			__func__);
329 		SetPageError(pg);
330 		ClearPageUptodate(pg);
331 	}
332 
333 	jffs2_dbg(1, "%s() returning %d\n",
334 		  __func__, writtenlen > 0 ? writtenlen : ret);
335 	unlock_page(pg);
336 	page_cache_release(pg);
337 	return writtenlen > 0 ? writtenlen : ret;
338 }
339