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