linux/fs/jffs2/file.c
<<
>>
Prefs
   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 = file_write_and_wait_range(filp, 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
  50const 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
  64const 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        .listxattr =    jffs2_listxattr,
  70};
  71
  72const struct address_space_operations jffs2_file_address_operations =
  73{
  74        .readpage =     jffs2_readpage,
  75        .write_begin =  jffs2_write_begin,
  76        .write_end =    jffs2_write_end,
  77};
  78
  79static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
  80{
  81        struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
  82        struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
  83        unsigned char *pg_buf;
  84        int ret;
  85
  86        jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n",
  87                  __func__, inode->i_ino, pg->index << PAGE_SHIFT);
  88
  89        BUG_ON(!PageLocked(pg));
  90
  91        pg_buf = kmap(pg);
  92        /* FIXME: Can kmap fail? */
  93
  94        ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_SHIFT,
  95                                     PAGE_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        jffs2_dbg(2, "readpage finished\n");
 109        return ret;
 110}
 111
 112int 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
 120static 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
 131static 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        pgoff_t index = pos >> PAGE_SHIFT;
 139        uint32_t pageofs = index << PAGE_SHIFT;
 140        int ret = 0;
 141
 142        pg = grab_cache_page_write_begin(mapping, index, flags);
 143        if (!pg)
 144                return -ENOMEM;
 145        *pagep = pg;
 146
 147        jffs2_dbg(1, "%s()\n", __func__);
 148
 149        if (pageofs > inode->i_size) {
 150                /* Make new hole frag from old EOF to new page */
 151                struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 152                struct jffs2_raw_inode ri;
 153                struct jffs2_full_dnode *fn;
 154                uint32_t alloc_len;
 155
 156                jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
 157                          (unsigned int)inode->i_size, pageofs);
 158
 159                ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
 160                                          ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
 161                if (ret)
 162                        goto out_page;
 163
 164                mutex_lock(&f->sem);
 165                memset(&ri, 0, sizeof(ri));
 166
 167                ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
 168                ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
 169                ri.totlen = cpu_to_je32(sizeof(ri));
 170                ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
 171
 172                ri.ino = cpu_to_je32(f->inocache->ino);
 173                ri.version = cpu_to_je32(++f->highest_version);
 174                ri.mode = cpu_to_jemode(inode->i_mode);
 175                ri.uid = cpu_to_je16(i_uid_read(inode));
 176                ri.gid = cpu_to_je16(i_gid_read(inode));
 177                ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
 178                ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());
 179                ri.offset = cpu_to_je32(inode->i_size);
 180                ri.dsize = cpu_to_je32(pageofs - inode->i_size);
 181                ri.csize = cpu_to_je32(0);
 182                ri.compr = JFFS2_COMPR_ZERO;
 183                ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
 184                ri.data_crc = cpu_to_je32(0);
 185
 186                fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
 187
 188                if (IS_ERR(fn)) {
 189                        ret = PTR_ERR(fn);
 190                        jffs2_complete_reservation(c);
 191                        mutex_unlock(&f->sem);
 192                        goto out_page;
 193                }
 194                ret = jffs2_add_full_dnode_to_inode(c, f, fn);
 195                if (f->metadata) {
 196                        jffs2_mark_node_obsolete(c, f->metadata->raw);
 197                        jffs2_free_full_dnode(f->metadata);
 198                        f->metadata = NULL;
 199                }
 200                if (ret) {
 201                        jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
 202                                  ret);
 203                        jffs2_mark_node_obsolete(c, fn->raw);
 204                        jffs2_free_full_dnode(fn);
 205                        jffs2_complete_reservation(c);
 206                        mutex_unlock(&f->sem);
 207                        goto out_page;
 208                }
 209                jffs2_complete_reservation(c);
 210                inode->i_size = pageofs;
 211                mutex_unlock(&f->sem);
 212        }
 213
 214        /*
 215         * Read in the page if it wasn't already present. Cannot optimize away
 216         * the whole page write case until jffs2_write_end can handle the
 217         * case of a short-copy.
 218         */
 219        if (!PageUptodate(pg)) {
 220                mutex_lock(&f->sem);
 221                ret = jffs2_do_readpage_nolock(inode, pg);
 222                mutex_unlock(&f->sem);
 223                if (ret)
 224                        goto out_page;
 225        }
 226        jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
 227        return ret;
 228
 229out_page:
 230        unlock_page(pg);
 231        put_page(pg);
 232        return ret;
 233}
 234
 235static int jffs2_write_end(struct file *filp, struct address_space *mapping,
 236                        loff_t pos, unsigned len, unsigned copied,
 237                        struct page *pg, void *fsdata)
 238{
 239        /* Actually commit the write from the page cache page we're looking at.
 240         * For now, we write the full page out each time. It sucks, but it's simple
 241         */
 242        struct inode *inode = mapping->host;
 243        struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 244        struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 245        struct jffs2_raw_inode *ri;
 246        unsigned start = pos & (PAGE_SIZE - 1);
 247        unsigned end = start + copied;
 248        unsigned aligned_start = start & ~3;
 249        int ret = 0;
 250        uint32_t writtenlen = 0;
 251
 252        jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
 253                  __func__, inode->i_ino, pg->index << PAGE_SHIFT,
 254                  start, end, pg->flags);
 255
 256        /* We need to avoid deadlock with page_cache_read() in
 257           jffs2_garbage_collect_pass(). So the page must be
 258           up to date to prevent page_cache_read() from trying
 259           to re-lock it. */
 260        BUG_ON(!PageUptodate(pg));
 261
 262        if (end == PAGE_SIZE) {
 263                /* When writing out the end of a page, write out the
 264                   _whole_ page. This helps to reduce the number of
 265                   nodes in files which have many short writes, like
 266                   syslog files. */
 267                aligned_start = 0;
 268        }
 269
 270        ri = jffs2_alloc_raw_inode();
 271
 272        if (!ri) {
 273                jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
 274                          __func__);
 275                unlock_page(pg);
 276                put_page(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(i_uid_read(inode));
 284        ri->gid = cpu_to_je16(i_gid_read(inode));
 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_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 = timespec_to_timespec64(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                jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n",
 322                        __func__);
 323                SetPageError(pg);
 324                ClearPageUptodate(pg);
 325        }
 326
 327        jffs2_dbg(1, "%s() returning %d\n",
 328                  __func__, writtenlen > 0 ? writtenlen : ret);
 329        unlock_page(pg);
 330        put_page(pg);
 331        return writtenlen > 0 ? writtenlen : ret;
 332}
 333