1506673c087e11ae820245baadc8ae74cb9f01b2
[linux-3.10.git] / fs / jffs2 / file.c
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         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
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
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
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
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(i_uid_read(inode));
185                 ri.gid = cpu_to_je16(i_gid_read(inode));
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
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(i_uid_read(inode));
290         ri->gid = cpu_to_je16(i_gid_read(inode));
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 }