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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_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  
jffs2_do_readpage_nolock(struct inode * inode,struct page * pg)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  
jffs2_do_readpage_unlock(struct inode * inode,struct page * pg)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  
jffs2_readpage(struct file * filp,struct page * pg)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  
jffs2_write_begin(struct file * filp,struct address_space * mapping,loff_t pos,unsigned len,unsigned flags,struct page ** pagep,void ** fsdata)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  
jffs2_write_end(struct file * filp,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * pg,void * fsdata)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