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 =         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
  66 const 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
  76 const 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
  83 static 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
 115 int 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
 123 static 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
 134 static 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
 232 out_page:
 233         unlock_page(pg);
 234         page_cache_release(pg);
 235         return ret;
 236 }
 237
 238 static 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 }