xref: /openbmc/linux/fs/jffs2/file.c (revision 92a76f6d)
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 
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 	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 =	generic_file_splice_read,
60 };
61 
62 /* jffs2_file_inode_operations */
63 
64 const 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 
75 const 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 
82 static 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 
114 int 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 
122 static 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 
133 static 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 
231 out_page:
232 	unlock_page(pg);
233 	page_cache_release(pg);
234 	return ret;
235 }
236 
237 static 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