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         .set_acl =      jffs2_set_acl,
  70         .setattr =      jffs2_setattr,
  71         .setxattr =     jffs2_setxattr,
  72         .getxattr =     jffs2_getxattr,
  73         .listxattr =    jffs2_listxattr,
  74         .removexattr =  jffs2_removexattr
  75 };
  76
  77 const struct address_space_operations jffs2_file_address_operations =
  78 {
  79         .readpage =     jffs2_readpage,
  80         .write_begin =  jffs2_write_begin,
  81         .write_end =    jffs2_write_end,
  82 };
  83
  84 static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
  85 {
  86         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
  87         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
  88         unsigned char *pg_buf;
  89         int ret;
  90
  91         jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n",
  92                   __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT);
  93
  94         BUG_ON(!PageLocked(pg));
  95
  96         pg_buf = kmap(pg);
  97         /* FIXME: Can kmap fail? */
  98
  99         ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE);
 100
 101         if (ret) {
 102                 ClearPageUptodate(pg);
 103                 SetPageError(pg);
 104         } else {
 105                 SetPageUptodate(pg);
 106                 ClearPageError(pg);
 107         }
 108
 109         flush_dcache_page(pg);
 110         kunmap(pg);
 111
 112         jffs2_dbg(2, "readpage finished\n");
 113         return ret;
 114 }
 115
 116 int jffs2_do_readpage_unlock(struct inode *inode, struct page *pg)
 117 {
 118         int ret = jffs2_do_readpage_nolock(inode, pg);
 119         unlock_page(pg);
 120         return ret;
 121 }
 122
 123
 124 static int jffs2_readpage (struct file *filp, struct page *pg)
 125 {
 126         struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
 127         int ret;
 128
 129         mutex_lock(&f->sem);
 130         ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
 131         mutex_unlock(&f->sem);
 132         return ret;
 133 }
 134
 135 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
 136                         loff_t pos, unsigned len, unsigned flags,
 137                         struct page **pagep, void **fsdata)
 138 {
 139         struct page *pg;
 140         struct inode *inode = mapping->host;
 141         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 142         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 143         struct jffs2_raw_inode ri;
 144         uint32_t alloc_len = 0;
 145         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 146         uint32_t pageofs = index << PAGE_CACHE_SHIFT;
 147         int ret = 0;
 148
 149         jffs2_dbg(1, "%s()\n", __func__);
 150
 151         if (pageofs > inode->i_size) {
 152                 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
 153                                           ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
 154                 if (ret)
 155                         return ret;
 156         }
 157
 158         mutex_lock(&f->sem);
 159         pg = grab_cache_page_write_begin(mapping, index, flags);
 160         if (!pg) {
 161                 if (alloc_len)
 162                         jffs2_complete_reservation(c);
 163                 mutex_unlock(&f->sem);
 164                 return -ENOMEM;
 165         }
 166         *pagep = pg;
 167
 168         if (alloc_len) {
 169                 /* Make new hole frag from old EOF to new page */
 170                 struct jffs2_full_dnode *fn;
 171
 172                 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
 173                           (unsigned int)inode->i_size, pageofs);
 174
 175                 memset(&ri, 0, sizeof(ri));
 176
 177                 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
 178                 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
 179                 ri.totlen = cpu_to_je32(sizeof(ri));
 180                 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
 181
 182                 ri.ino = cpu_to_je32(f->inocache->ino);
 183                 ri.version = cpu_to_je32(++f->highest_version);
 184                 ri.mode = cpu_to_jemode(inode->i_mode);
 185                 ri.uid = cpu_to_je16(i_uid_read(inode));
 186                 ri.gid = cpu_to_je16(i_gid_read(inode));
 187                 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
 188                 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());
 189                 ri.offset = cpu_to_je32(inode->i_size);
 190                 ri.dsize = cpu_to_je32(pageofs - inode->i_size);
 191                 ri.csize = cpu_to_je32(0);
 192                 ri.compr = JFFS2_COMPR_ZERO;
 193                 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
 194                 ri.data_crc = cpu_to_je32(0);
 195
 196                 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
 197
 198                 if (IS_ERR(fn)) {
 199                         ret = PTR_ERR(fn);
 200                         jffs2_complete_reservation(c);
 201                         goto out_page;
 202                 }
 203                 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
 204                 if (f->metadata) {
 205                         jffs2_mark_node_obsolete(c, f->metadata->raw);
 206                         jffs2_free_full_dnode(f->metadata);
 207                         f->metadata = NULL;
 208                 }
 209                 if (ret) {
 210                         jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
 211                                   ret);
 212                         jffs2_mark_node_obsolete(c, fn->raw);
 213                         jffs2_free_full_dnode(fn);
 214                         jffs2_complete_reservation(c);
 215                         goto out_page;
 216                 }
 217                 jffs2_complete_reservation(c);
 218                 inode->i_size = pageofs;
 219         }
 220
 221         /*
 222          * Read in the page if it wasn't already present. Cannot optimize away
 223          * the whole page write case until jffs2_write_end can handle the
 224          * case of a short-copy.
 225          */
 226         if (!PageUptodate(pg)) {
 227                 ret = jffs2_do_readpage_nolock(inode, pg);
 228                 if (ret)
 229                         goto out_page;
 230         }
 231         mutex_unlock(&f->sem);
 232         jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
 233         return ret;
 234
 235 out_page:
 236         unlock_page(pg);
 237         page_cache_release(pg);
 238         mutex_unlock(&f->sem);
 239         return ret;
 240 }
 241
 242 static int jffs2_write_end(struct file *filp, struct address_space *mapping,
 243                         loff_t pos, unsigned len, unsigned copied,
 244                         struct page *pg, void *fsdata)
 245 {
 246         /* Actually commit the write from the page cache page we're looking at.
 247          * For now, we write the full page out each time. It sucks, but it's simple
 248          */
 249         struct inode *inode = mapping->host;
 250         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 251         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 252         struct jffs2_raw_inode *ri;
 253         unsigned start = pos & (PAGE_CACHE_SIZE - 1);
 254         unsigned end = start + copied;
 255         unsigned aligned_start = start & ~3;
 256         int ret = 0;
 257         uint32_t writtenlen = 0;
 258
 259         jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
 260                   __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT,
 261                   start, end, pg->flags);
 262
 263         /* We need to avoid deadlock with page_cache_read() in
 264            jffs2_garbage_collect_pass(). So the page must be
 265            up to date to prevent page_cache_read() from trying
 266            to re-lock it. */
 267         BUG_ON(!PageUptodate(pg));
 268
 269         if (end == PAGE_CACHE_SIZE) {
 270                 /* When writing out the end of a page, write out the
 271                    _whole_ page. This helps to reduce the number of
 272                    nodes in files which have many short writes, like
 273                    syslog files. */
 274                 aligned_start = 0;
 275         }
 276
 277         ri = jffs2_alloc_raw_inode();
 278
 279         if (!ri) {
 280                 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
 281                           __func__);
 282                 unlock_page(pg);
 283                 page_cache_release(pg);
 284                 return -ENOMEM;
 285         }
 286
 287         /* Set the fields that the generic jffs2_write_inode_range() code can't find */
 288         ri->ino = cpu_to_je32(inode->i_ino);
 289         ri->mode = cpu_to_jemode(inode->i_mode);
 290         ri->uid = cpu_to_je16(i_uid_read(inode));
 291         ri->gid = cpu_to_je16(i_gid_read(inode));
 292         ri->isize = cpu_to_je32((uint32_t)inode->i_size);
 293         ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds());
 294
 295         /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
 296            hurt to do it again. The alternative is ifdefs, which are ugly. */
 297         kmap(pg);
 298
 299         ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
 300                                       (pg->index << PAGE_CACHE_SHIFT) + aligned_start,
 301                                       end - aligned_start, &writtenlen);
 302
 303         kunmap(pg);
 304
 305         if (ret) {
 306                 /* There was an error writing. */
 307                 SetPageError(pg);
 308         }
 309
 310         /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
 311         writtenlen -= min(writtenlen, (start - aligned_start));
 312
 313         if (writtenlen) {
 314                 if (inode->i_size < pos + writtenlen) {
 315                         inode->i_size = pos + writtenlen;
 316                         inode->i_blocks = (inode->i_size + 511) >> 9;
 317
 318                         inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
 319                 }
 320         }
 321
 322         jffs2_free_raw_inode(ri);
 323
 324         if (start+writtenlen < end) {
 325                 /* generic_file_write has written more to the page cache than we've
 326                    actually written to the medium. Mark the page !Uptodate so that
 327                    it gets reread */
 328                 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n",
 329                         __func__);
 330                 SetPageError(pg);
 331                 ClearPageUptodate(pg);
 332         }
 333
 334         jffs2_dbg(1, "%s() returning %d\n",
 335                   __func__, writtenlen > 0 ? writtenlen : ret);
 336         unlock_page(pg);
 337         page_cache_release(pg);
 338         return writtenlen > 0 ? writtenlen : ret;
 339 }