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 #include <linux/kernel.h>
  14 #include <linux/fs.h>
  15 #include <linux/time.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/highmem.h>
  18 #include <linux/crc32.h>
  19 #include <linux/jffs2.h>
  20 #include "nodelist.h"
  21
  22 static int jffs2_write_end(struct file *filp, struct address_space *mapping,
  23                         loff_t pos, unsigned len, unsigned copied,
  24                         struct page *pg, void *fsdata);
  25 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
  26                         loff_t pos, unsigned len, unsigned flags,
  27                         struct page **pagep, void **fsdata);
  28 static int jffs2_readpage (struct file *filp, struct page *pg);
  29
  30 int jffs2_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
  31 {
  32         struct inode *inode = filp->f_mapping->host;
  33         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
  34         int ret;
  35
  36         ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
  37         if (ret)
  38                 return ret;
  39
  40         mutex_lock(&inode->i_mutex);
  41         /* Trigger GC to flush any pending writes for this inode */
  42         jffs2_flush_wbuf_gc(c, inode->i_ino);
  43         mutex_unlock(&inode->i_mutex);
  44
  45         return 0;
  46 }
  47
  48 const struct file_operations jffs2_file_operations =
  49 {
  50         .llseek =       generic_file_llseek,
  51         .open =         generic_file_open,
  52         .read =         do_sync_read,
  53         .aio_read =     generic_file_aio_read,
  54         .write =        do_sync_write,
  55         .aio_write =    generic_file_aio_write,
  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         .setattr =      jffs2_setattr,
  68         .setxattr =     jffs2_setxattr,
  69         .getxattr =     jffs2_getxattr,
  70         .listxattr =    jffs2_listxattr,
  71         .removexattr =  jffs2_removexattr
  72 };
  73
  74 const struct address_space_operations jffs2_file_address_operations =
  75 {
  76         .readpage =     jffs2_readpage,
  77         .write_begin =  jffs2_write_begin,
  78         .write_end =    jffs2_write_end,
  79 };
  80
  81 static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
  82 {
  83         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
  84         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
  85         unsigned char *pg_buf;
  86         int ret;
  87
  88         D2(printk(KERN_DEBUG "jffs2_do_readpage_nolock(): ino #%lu, page at offset 0x%lx\n", inode->i_ino, pg->index << PAGE_CACHE_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_CACHE_SHIFT, PAGE_CACHE_SIZE);
  96
  97         if (ret) {
  98                 ClearPageUptodate(pg);
  99                 SetPageError(pg);
 100         } else {
 101                 SetPageUptodate(pg);
 102                 ClearPageError(pg);
 103         }
 104
 105         flush_dcache_page(pg);
 106         kunmap(pg);
 107
 108         D2(printk(KERN_DEBUG "readpage finished\n"));
 109         return ret;
 110 }
 111
 112 int jffs2_do_readpage_unlock(struct inode *inode, struct page *pg)
 113 {
 114         int ret = jffs2_do_readpage_nolock(inode, pg);
 115         unlock_page(pg);
 116         return ret;
 117 }
 118
 119
 120 static int jffs2_readpage (struct file *filp, struct page *pg)
 121 {
 122         struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
 123         int ret;
 124
 125         mutex_lock(&f->sem);
 126         ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
 127         mutex_unlock(&f->sem);
 128         return ret;
 129 }
 130
 131 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
 132                         loff_t pos, unsigned len, unsigned flags,
 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         struct jffs2_raw_inode ri;
 140         uint32_t alloc_len = 0;
 141         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 142         uint32_t pageofs = index << PAGE_CACHE_SHIFT;
 143         int ret = 0;
 144
 145         D1(printk(KERN_DEBUG "%s()\n", __func__));
 146
 147         if (pageofs > inode->i_size) {
 148                 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
 149                                           ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
 150                 if (ret)
 151                         return ret;
 152         }
 153
 154         mutex_lock(&f->sem);
 155         pg = grab_cache_page_write_begin(mapping, index, flags);
 156         if (!pg) {
 157                 if (alloc_len)
 158                         jffs2_complete_reservation(c);
 159                 mutex_unlock(&f->sem);
 160                 return -ENOMEM;
 161         }
 162         *pagep = pg;
 163
 164         if (alloc_len) {
 165                 /* Make new hole frag from old EOF to new page */
 166                 struct jffs2_full_dnode *fn;
 167
 168                 D1(printk(KERN_DEBUG "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
 169                           (unsigned int)inode->i_size, pageofs));
 170
 171                 memset(&ri, 0, sizeof(ri));
 172
 173                 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
 174                 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
 175                 ri.totlen = cpu_to_je32(sizeof(ri));
 176                 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
 177
 178                 ri.ino = cpu_to_je32(f->inocache->ino);
 179                 ri.version = cpu_to_je32(++f->highest_version);
 180                 ri.mode = cpu_to_jemode(inode->i_mode);
 181                 ri.uid = cpu_to_je16(inode->i_uid);
 182                 ri.gid = cpu_to_je16(inode->i_gid);
 183                 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
 184                 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());
 185                 ri.offset = cpu_to_je32(inode->i_size);
 186                 ri.dsize = cpu_to_je32(pageofs - inode->i_size);
 187                 ri.csize = cpu_to_je32(0);
 188                 ri.compr = JFFS2_COMPR_ZERO;
 189                 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
 190                 ri.data_crc = cpu_to_je32(0);
 191
 192                 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
 193
 194                 if (IS_ERR(fn)) {
 195                         ret = PTR_ERR(fn);
 196                         jffs2_complete_reservation(c);
 197                         goto out_page;
 198                 }
 199                 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
 200                 if (f->metadata) {
 201                         jffs2_mark_node_obsolete(c, f->metadata->raw);
 202                         jffs2_free_full_dnode(f->metadata);
 203                         f->metadata = NULL;
 204                 }
 205                 if (ret) {
 206                         D1(printk(KERN_DEBUG "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", ret));
 207                         jffs2_mark_node_obsolete(c, fn->raw);
 208                         jffs2_free_full_dnode(fn);
 209                         jffs2_complete_reservation(c);
 210                         goto out_page;
 211                 }
 212                 jffs2_complete_reservation(c);
 213                 inode->i_size = pageofs;
 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                 ret = jffs2_do_readpage_nolock(inode, pg);
 223                 if (ret)
 224                         goto out_page;
 225         }
 226         mutex_unlock(&f->sem);
 227         D1(printk(KERN_DEBUG "end write_begin(). pg->flags %lx\n", pg->flags));
 228         return ret;
 229
 230 out_page:
 231         unlock_page(pg);
 232         page_cache_release(pg);
 233         mutex_unlock(&f->sem);
 234         return ret;
 235 }
 236
 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         D1(printk(KERN_DEBUG "jffs2_write_end(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
 255                   inode->i_ino, pg->index << PAGE_CACHE_SHIFT, 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_CACHE_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                 D1(printk(KERN_DEBUG "jffs2_write_end(): Allocation of raw inode failed\n"));
 275                 unlock_page(pg);
 276                 page_cache_release(pg);
 277                 return -ENOMEM;
 278         }
 279
 280         /* Set the fields that the generic jffs2_write_inode_range() code can't find */
 281         ri->ino = cpu_to_je32(inode->i_ino);
 282         ri->mode = cpu_to_jemode(inode->i_mode);
 283         ri->uid = cpu_to_je16(inode->i_uid);
 284         ri->gid = cpu_to_je16(inode->i_gid);
 285         ri->isize = cpu_to_je32((uint32_t)inode->i_size);
 286         ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds());
 287
 288         /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
 289            hurt to do it again. The alternative is ifdefs, which are ugly. */
 290         kmap(pg);
 291
 292         ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
 293                                       (pg->index << PAGE_CACHE_SHIFT) + aligned_start,
 294                                       end - aligned_start, &writtenlen);
 295
 296         kunmap(pg);
 297
 298         if (ret) {
 299                 /* There was an error writing. */
 300                 SetPageError(pg);
 301         }
 302
 303         /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
 304         writtenlen -= min(writtenlen, (start - aligned_start));
 305
 306         if (writtenlen) {
 307                 if (inode->i_size < pos + writtenlen) {
 308                         inode->i_size = pos + writtenlen;
 309                         inode->i_blocks = (inode->i_size + 511) >> 9;
 310
 311                         inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
 312                 }
 313         }
 314
 315         jffs2_free_raw_inode(ri);
 316
 317         if (start+writtenlen < end) {
 318                 /* generic_file_write has written more to the page cache than we've
 319                    actually written to the medium. Mark the page !Uptodate so that
 320                    it gets reread */
 321                 D1(printk(KERN_DEBUG "jffs2_write_end(): Not all bytes written. Marking page !uptodate\n"));
 322                 SetPageError(pg);
 323                 ClearPageUptodate(pg);
 324         }
 325
 326         D1(printk(KERN_DEBUG "jffs2_write_end() returning %d\n",
 327                                         writtenlen > 0 ? writtenlen : ret));
 328         unlock_page(pg);
 329         page_cache_release(pg);
 330         return writtenlen > 0 ? writtenlen : ret;
 331 }