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Linux/fs/jffs2/file.c

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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 
 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 =  generic_file_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_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         .readpage =     jffs2_readpage,
 76         .write_begin =  jffs2_write_begin,
 77         .write_end =    jffs2_write_end,
 78 };
 79 
 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 
113 int jffs2_do_readpage_unlock(void *data, struct page *pg)
114 {
115         int ret = jffs2_do_readpage_nolock(data, pg);
116         unlock_page(pg);
117         return ret;
118 }
119 
120 
121 static int jffs2_readpage (struct file *filp, struct page *pg)
122 {
123         struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
124         int ret;
125 
126         mutex_lock(&f->sem);
127         ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
128         mutex_unlock(&f->sem);
129         return ret;
130 }
131 
132 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
133                         loff_t pos, unsigned len, unsigned flags,
134                         struct page **pagep, void **fsdata)
135 {
136         struct page *pg;
137         struct inode *inode = mapping->host;
138         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
139         pgoff_t index = pos >> PAGE_SHIFT;
140         uint32_t pageofs = index << PAGE_SHIFT;
141         int ret = 0;
142 
143         pg = grab_cache_page_write_begin(mapping, index, flags);
144         if (!pg)
145                 return -ENOMEM;
146         *pagep = pg;
147 
148         jffs2_dbg(1, "%s()\n", __func__);
149 
150         if (pageofs > inode->i_size) {
151                 /* Make new hole frag from old EOF to new page */
152                 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
153                 struct jffs2_raw_inode ri;
154                 struct jffs2_full_dnode *fn;
155                 uint32_t alloc_len;
156 
157                 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
158                           (unsigned int)inode->i_size, pageofs);
159 
160                 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
161                                           ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
162                 if (ret)
163                         goto out_page;
164 
165                 mutex_lock(&f->sem);
166                 memset(&ri, 0, sizeof(ri));
167 
168                 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
169                 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
170                 ri.totlen = cpu_to_je32(sizeof(ri));
171                 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
172 
173                 ri.ino = cpu_to_je32(f->inocache->ino);
174                 ri.version = cpu_to_je32(++f->highest_version);
175                 ri.mode = cpu_to_jemode(inode->i_mode);
176                 ri.uid = cpu_to_je16(i_uid_read(inode));
177                 ri.gid = cpu_to_je16(i_gid_read(inode));
178                 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
179                 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW());
180                 ri.offset = cpu_to_je32(inode->i_size);
181                 ri.dsize = cpu_to_je32(pageofs - inode->i_size);
182                 ri.csize = cpu_to_je32(0);
183                 ri.compr = JFFS2_COMPR_ZERO;
184                 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
185                 ri.data_crc = cpu_to_je32(0);
186 
187                 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
188 
189                 if (IS_ERR(fn)) {
190                         ret = PTR_ERR(fn);
191                         jffs2_complete_reservation(c);
192                         mutex_unlock(&f->sem);
193                         goto out_page;
194                 }
195                 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
196                 if (f->metadata) {
197                         jffs2_mark_node_obsolete(c, f->metadata->raw);
198                         jffs2_free_full_dnode(f->metadata);
199                         f->metadata = NULL;
200                 }
201                 if (ret) {
202                         jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
203                                   ret);
204                         jffs2_mark_node_obsolete(c, fn->raw);
205                         jffs2_free_full_dnode(fn);
206                         jffs2_complete_reservation(c);
207                         mutex_unlock(&f->sem);
208                         goto out_page;
209                 }
210                 jffs2_complete_reservation(c);
211                 inode->i_size = pageofs;
212                 mutex_unlock(&f->sem);
213         }
214 
215         /*
216          * Read in the page if it wasn't already present. Cannot optimize away
217          * the whole page write case until jffs2_write_end can handle the
218          * case of a short-copy.
219          */
220         if (!PageUptodate(pg)) {
221                 mutex_lock(&f->sem);
222                 ret = jffs2_do_readpage_nolock(inode, pg);
223                 mutex_unlock(&f->sem);
224                 if (ret)
225                         goto out_page;
226         }
227         jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
228         return ret;
229 
230 out_page:
231         unlock_page(pg);
232         put_page(pg);
233         return ret;
234 }
235 
236 static int jffs2_write_end(struct file *filp, struct address_space *mapping,
237                         loff_t pos, unsigned len, unsigned copied,
238                         struct page *pg, void *fsdata)
239 {
240         /* Actually commit the write from the page cache page we're looking at.
241          * For now, we write the full page out each time. It sucks, but it's simple
242          */
243         struct inode *inode = mapping->host;
244         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
245         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
246         struct jffs2_raw_inode *ri;
247         unsigned start = pos & (PAGE_SIZE - 1);
248         unsigned end = start + copied;
249         unsigned aligned_start = start & ~3;
250         int ret = 0;
251         uint32_t writtenlen = 0;
252 
253         jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
254                   __func__, inode->i_ino, pg->index << PAGE_SHIFT,
255                   start, end, pg->flags);
256 
257         /* We need to avoid deadlock with page_cache_read() in
258            jffs2_garbage_collect_pass(). So the page must be
259            up to date to prevent page_cache_read() from trying
260            to re-lock it. */
261         BUG_ON(!PageUptodate(pg));
262 
263         if (end == PAGE_SIZE) {
264                 /* When writing out the end of a page, write out the
265                    _whole_ page. This helps to reduce the number of
266                    nodes in files which have many short writes, like
267                    syslog files. */
268                 aligned_start = 0;
269         }
270 
271         ri = jffs2_alloc_raw_inode();
272 
273         if (!ri) {
274                 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
275                           __func__);
276                 unlock_page(pg);
277                 put_page(pg);
278                 return -ENOMEM;
279         }
280 
281         /* Set the fields that the generic jffs2_write_inode_range() code can't find */
282         ri->ino = cpu_to_je32(inode->i_ino);
283         ri->mode = cpu_to_jemode(inode->i_mode);
284         ri->uid = cpu_to_je16(i_uid_read(inode));
285         ri->gid = cpu_to_je16(i_gid_read(inode));
286         ri->isize = cpu_to_je32((uint32_t)inode->i_size);
287         ri->atime = ri->ctime = ri->mtime = cpu_to_je32(JFFS2_NOW());
288 
289         /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
290            hurt to do it again. The alternative is ifdefs, which are ugly. */
291         kmap(pg);
292 
293         ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
294                                       (pg->index << PAGE_SHIFT) + aligned_start,
295                                       end - aligned_start, &writtenlen);
296 
297         kunmap(pg);
298 
299         if (ret) {
300                 /* There was an error writing. */
301                 SetPageError(pg);
302         }
303 
304         /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
305         writtenlen -= min(writtenlen, (start - aligned_start));
306 
307         if (writtenlen) {
308                 if (inode->i_size < pos + writtenlen) {
309                         inode->i_size = pos + writtenlen;
310                         inode->i_blocks = (inode->i_size + 511) >> 9;
311 
312                         inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
313                 }
314         }
315 
316         jffs2_free_raw_inode(ri);
317 
318         if (start+writtenlen < end) {
319                 /* generic_file_write has written more to the page cache than we've
320                    actually written to the medium. Mark the page !Uptodate so that
321                    it gets reread */
322                 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n",
323                         __func__);
324                 SetPageError(pg);
325                 ClearPageUptodate(pg);
326         }
327 
328         jffs2_dbg(1, "%s() returning %d\n",
329                   __func__, writtenlen > 0 ? writtenlen : ret);
330         unlock_page(pg);
331         put_page(pg);
332         return writtenlen > 0 ? writtenlen : ret;
333 }
334 

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