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
  24static 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);
  27static 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);
  30static int jffs2_readpage (struct file *filp, struct page *pg);
  31
  32int 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
  50const 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
  66const 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
  76const 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
  83static 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
 115int 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
 123static 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
 134static 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
 234out_page:
 235        unlock_page(pg);
 236        page_cache_release(pg);
 237        mutex_unlock(&f->sem);
 238        return ret;
 239}
 240
 241static 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}
 339
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