xref: /openbmc/linux/fs/jffs2/file.c (revision d8b23c61)
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,
29 			struct page **pagep, void **fsdata);
30 static int jffs2_read_folio(struct file *filp, struct folio *folio);
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 = 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 
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 =	filemap_splice_read,
60 	.splice_write = iter_file_splice_write,
61 };
62 
63 /* jffs2_file_inode_operations */
64 
65 const 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 
73 const 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 
jffs2_do_readpage_nolock(struct inode * inode,struct page * pg)80 static 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 
__jffs2_read_folio(struct file * file,struct folio * folio)113 int __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 
jffs2_read_folio(struct file * file,struct folio * folio)120 static 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 
jffs2_write_begin(struct file * filp,struct address_space * mapping,loff_t pos,unsigned len,struct page ** pagep,void ** fsdata)131 static 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 
238 release_sem:
239 	mutex_unlock(&c->alloc_sem);
240 out_err:
241 	return ret;
242 }
243 
jffs2_write_end(struct file * filp,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * pg,void * fsdata)244 static 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->i_mtime = inode_set_ctime_to_ts(inode,
321 							       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