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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 = 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_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_SHIFT,
 98                                      PAGE_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         pgoff_t index = pos >> PAGE_SHIFT;
142         uint32_t pageofs = index << PAGE_SHIFT;
143         int ret = 0;
144 
145         pg = grab_cache_page_write_begin(mapping, index, flags);
146         if (!pg)
147                 return -ENOMEM;
148         *pagep = pg;
149 
150         jffs2_dbg(1, "%s()\n", __func__);
151 
152         if (pageofs > inode->i_size) {
153                 /* Make new hole frag from old EOF to new page */
154                 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
155                 struct jffs2_raw_inode ri;
156                 struct jffs2_full_dnode *fn;
157                 uint32_t alloc_len;
158 
159                 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
160                           (unsigned int)inode->i_size, pageofs);
161 
162                 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
163                                           ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
164                 if (ret)
165                         goto out_page;
166 
167                 mutex_lock(&f->sem);
168                 memset(&ri, 0, sizeof(ri));
169 
170                 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
171                 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
172                 ri.totlen = cpu_to_je32(sizeof(ri));
173                 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
174 
175                 ri.ino = cpu_to_je32(f->inocache->ino);
176                 ri.version = cpu_to_je32(++f->highest_version);
177                 ri.mode = cpu_to_jemode(inode->i_mode);
178                 ri.uid = cpu_to_je16(i_uid_read(inode));
179                 ri.gid = cpu_to_je16(i_gid_read(inode));
180                 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
181                 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());
182                 ri.offset = cpu_to_je32(inode->i_size);
183                 ri.dsize = cpu_to_je32(pageofs - inode->i_size);
184                 ri.csize = cpu_to_je32(0);
185                 ri.compr = JFFS2_COMPR_ZERO;
186                 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
187                 ri.data_crc = cpu_to_je32(0);
188 
189                 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
190 
191                 if (IS_ERR(fn)) {
192                         ret = PTR_ERR(fn);
193                         jffs2_complete_reservation(c);
194                         mutex_unlock(&f->sem);
195                         goto out_page;
196                 }
197                 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
198                 if (f->metadata) {
199                         jffs2_mark_node_obsolete(c, f->metadata->raw);
200                         jffs2_free_full_dnode(f->metadata);
201                         f->metadata = NULL;
202                 }
203                 if (ret) {
204                         jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
205                                   ret);
206                         jffs2_mark_node_obsolete(c, fn->raw);
207                         jffs2_free_full_dnode(fn);
208                         jffs2_complete_reservation(c);
209                         mutex_unlock(&f->sem);
210                         goto out_page;
211                 }
212                 jffs2_complete_reservation(c);
213                 inode->i_size = pageofs;
214                 mutex_unlock(&f->sem);
215         }
216 
217         /*
218          * Read in the page if it wasn't already present. Cannot optimize away
219          * the whole page write case until jffs2_write_end can handle the
220          * case of a short-copy.
221          */
222         if (!PageUptodate(pg)) {
223                 mutex_lock(&f->sem);
224                 ret = jffs2_do_readpage_nolock(inode, pg);
225                 mutex_unlock(&f->sem);
226                 if (ret)
227                         goto out_page;
228         }
229         jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
230         return ret;
231 
232 out_page:
233         unlock_page(pg);
234         put_page(pg);
235         return ret;
236 }
237 
238 static int jffs2_write_end(struct file *filp, struct address_space *mapping,
239                         loff_t pos, unsigned len, unsigned copied,
240                         struct page *pg, void *fsdata)
241 {
242         /* Actually commit the write from the page cache page we're looking at.
243          * For now, we write the full page out each time. It sucks, but it's simple
244          */
245         struct inode *inode = mapping->host;
246         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
247         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
248         struct jffs2_raw_inode *ri;
249         unsigned start = pos & (PAGE_SIZE - 1);
250         unsigned end = start + copied;
251         unsigned aligned_start = start & ~3;
252         int ret = 0;
253         uint32_t writtenlen = 0;
254 
255         jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
256                   __func__, inode->i_ino, pg->index << PAGE_SHIFT,
257                   start, end, pg->flags);
258 
259         /* We need to avoid deadlock with page_cache_read() in
260            jffs2_garbage_collect_pass(). So the page must be
261            up to date to prevent page_cache_read() from trying
262            to re-lock it. */
263         BUG_ON(!PageUptodate(pg));
264 
265         if (end == PAGE_SIZE) {
266                 /* When writing out the end of a page, write out the
267                    _whole_ page. This helps to reduce the number of
268                    nodes in files which have many short writes, like
269                    syslog files. */
270                 aligned_start = 0;
271         }
272 
273         ri = jffs2_alloc_raw_inode();
274 
275         if (!ri) {
276                 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
277                           __func__);
278                 unlock_page(pg);
279                 put_page(pg);
280                 return -ENOMEM;
281         }
282 
283         /* Set the fields that the generic jffs2_write_inode_range() code can't find */
284         ri->ino = cpu_to_je32(inode->i_ino);
285         ri->mode = cpu_to_jemode(inode->i_mode);
286         ri->uid = cpu_to_je16(i_uid_read(inode));
287         ri->gid = cpu_to_je16(i_gid_read(inode));
288         ri->isize = cpu_to_je32((uint32_t)inode->i_size);
289         ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds());
290 
291         /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
292            hurt to do it again. The alternative is ifdefs, which are ugly. */
293         kmap(pg);
294 
295         ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
296                                       (pg->index << PAGE_SHIFT) + aligned_start,
297                                       end - aligned_start, &writtenlen);
298 
299         kunmap(pg);
300 
301         if (ret) {
302                 /* There was an error writing. */
303                 SetPageError(pg);
304         }
305 
306         /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
307         writtenlen -= min(writtenlen, (start - aligned_start));
308 
309         if (writtenlen) {
310                 if (inode->i_size < pos + writtenlen) {
311                         inode->i_size = pos + writtenlen;
312                         inode->i_blocks = (inode->i_size + 511) >> 9;
313 
314                         inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
315                 }
316         }
317 
318         jffs2_free_raw_inode(ri);
319 
320         if (start+writtenlen < end) {
321                 /* generic_file_write has written more to the page cache than we've
322                    actually written to the medium. Mark the page !Uptodate so that
323                    it gets reread */
324                 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n",
325                         __func__);
326                 SetPageError(pg);
327                 ClearPageUptodate(pg);
328         }
329 
330         jffs2_dbg(1, "%s() returning %d\n",
331                   __func__, writtenlen > 0 ? writtenlen : ret);
332         unlock_page(pg);
333         put_page(pg);
334         return writtenlen > 0 ? writtenlen : ret;
335 }
336 

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