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        pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 142        uint32_t pageofs = index << PAGE_CACHE_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(inode->i_uid);
 179                ri.gid = cpu_to_je16(inode->i_gid);
 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
 232out_page:
 233        unlock_page(pg);
 234        page_cache_release(pg);
 235        return ret;
 236}
 237
 238static 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_CACHE_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_CACHE_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_CACHE_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                page_cache_release(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(inode->i_uid);
 287        ri->gid = cpu_to_je16(inode->i_gid);
 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_CACHE_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        page_cache_release(pg);
 334        return writtenlen > 0 ? writtenlen : ret;
 335}
 336
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