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         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
  50 const 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
  64 const 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
  72 const 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
  79 static 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
 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         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
 229 out_page:
 230         unlock_page(pg);
 231         put_page(pg);
 232         return ret;
 233 }
 234
 235 static 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 = 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 }