fs/jffs2/file.c

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright © 2001-2007 Red Hat, Inc.
   5  *
   6  * Created by David Woodhouse <dwmw2@infradead.org>
   7  *
   8  * For licensing information, see the file 'LICENCE' in this directory.
   9  *
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/slab.h>
  14 #include <linux/fs.h>
  15 #include <linux/time.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/highmem.h>
  18 #include <linux/crc32.h>
  19 #include <linux/jffs2.h>
  20 #include "nodelist.h"
  21
  22 static int jffs2_write_end(struct file *filp, struct address_space *mapping,
  23                         loff_t pos, unsigned len, unsigned copied,
  24                         struct page *pg, void *fsdata);
  25 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
  26                         loff_t pos, unsigned len, unsigned flags,
  27                         struct page **pagep, void **fsdata);
  28 static int jffs2_readpage (struct file *filp, struct page *pg);
  29
  30 int jffs2_fsync(struct file *filp, struct dentry *dentry, int datasync)
  31 {
  32         struct inode *inode = dentry->d_inode;
  33         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
  34
  35         /* Trigger GC to flush any pending writes for this inode */
  36         jffs2_flush_wbuf_gc(c, inode->i_ino);
  37
  38         return 0;
  39 }
  40
  41 const struct file_operations jffs2_file_operations =
  42 {
  43         .llseek =       generic_file_llseek,
  44         .open =         generic_file_open,
  45         .read =         do_sync_read,
  46         .aio_read =     generic_file_aio_read,
  47         .write =        do_sync_write,
  48         .aio_write =    generic_file_aio_write,
  49         .unlocked_ioctl=jffs2_ioctl,
  50         .mmap =         generic_file_readonly_mmap,
  51         .fsync =        jffs2_fsync,
  52         .splice_read =  generic_file_splice_read,
  53 };
  54
  55 /* jffs2_file_inode_operations */
  56
  57 const struct inode_operations jffs2_file_inode_operations =
  58 {
  59         .permission =   jffs2_permission,
  60         .setattr =      jffs2_setattr,
  61         .setxattr =     jffs2_setxattr,
  62         .getxattr =     jffs2_getxattr,
  63         .listxattr =    jffs2_listxattr,
  64         .removexattr =  jffs2_removexattr
  65 };
  66
  67 const struct address_space_operations jffs2_file_address_operations =
  68 {
  69         .readpage =     jffs2_readpage,
  70         .write_begin =  jffs2_write_begin,
  71         .write_end =    jffs2_write_end,
  72 };
  73
  74 static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
  75 {
  76         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
  77         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
  78         unsigned char *pg_buf;
  79         int ret;
  80
  81         D2(printk(KERN_DEBUG "jffs2_do_readpage_nolock(): ino #%lu, page at offset 0x%lx\n", inode->i_ino, pg->index << PAGE_CACHE_SHIFT));
  82
  83         BUG_ON(!PageLocked(pg));
  84
  85         pg_buf = kmap(pg);
  86         /* FIXME: Can kmap fail? */
  87
  88         ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE);
  89
  90         if (ret) {
  91                 ClearPageUptodate(pg);
  92                 SetPageError(pg);
  93         } else {
  94                 SetPageUptodate(pg);
  95                 ClearPageError(pg);
  96         }
  97
  98         flush_dcache_page(pg);
  99         kunmap(pg);
 100
 101         D2(printk(KERN_DEBUG "readpage finished\n"));
 102         return 0;
 103 }
 104
 105 int jffs2_do_readpage_unlock(struct inode *inode, struct page *pg)
 106 {
 107         int ret = jffs2_do_readpage_nolock(inode, pg);
 108         unlock_page(pg);
 109         return ret;
 110 }
 111
 112
 113 static int jffs2_readpage (struct file *filp, struct page *pg)
 114 {
 115         struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
 116         int ret;
 117
 118         mutex_lock(&f->sem);
 119         ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
 120         mutex_unlock(&f->sem);
 121         return ret;
 122 }
 123
 124 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
 125                         loff_t pos, unsigned len, unsigned flags,
 126                         struct page **pagep, void **fsdata)
 127 {
 128         struct page *pg;
 129         struct inode *inode = mapping->host;
 130         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 131         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 132         uint32_t pageofs = index << PAGE_CACHE_SHIFT;
 133         int ret = 0;
 134
 135         pg = grab_cache_page_write_begin(mapping, index, flags);
 136         if (!pg)
 137                 return -ENOMEM;
 138         *pagep = pg;
 139
 140         D1(printk(KERN_DEBUG "jffs2_write_begin()\n"));
 141
 142         if (pageofs > inode->i_size) {
 143                 /* Make new hole frag from old EOF to new page */
 144                 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 145                 struct jffs2_raw_inode ri;
 146                 struct jffs2_full_dnode *fn;
 147                 uint32_t alloc_len;
 148
 149                 D1(printk(KERN_DEBUG "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
 150                           (unsigned int)inode->i_size, pageofs));
 151
 152                 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
 153                                           ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
 154                 if (ret)
 155                         goto out_page;
 156
 157                 mutex_lock(&f->sem);
 158                 memset(&ri, 0, sizeof(ri));
 159
 160                 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
 161                 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
 162                 ri.totlen = cpu_to_je32(sizeof(ri));
 163                 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
 164
 165                 ri.ino = cpu_to_je32(f->inocache->ino);
 166                 ri.version = cpu_to_je32(++f->highest_version);
 167                 ri.mode = cpu_to_jemode(inode->i_mode);
 168                 ri.uid = cpu_to_je16(inode->i_uid);
 169                 ri.gid = cpu_to_je16(inode->i_gid);
 170                 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
 171                 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());
 172                 ri.offset = cpu_to_je32(inode->i_size);
 173                 ri.dsize = cpu_to_je32(pageofs - inode->i_size);
 174                 ri.csize = cpu_to_je32(0);
 175                 ri.compr = JFFS2_COMPR_ZERO;
 176                 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
 177                 ri.data_crc = cpu_to_je32(0);
 178
 179                 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
 180
 181                 if (IS_ERR(fn)) {
 182                         ret = PTR_ERR(fn);
 183                         jffs2_complete_reservation(c);
 184                         mutex_unlock(&f->sem);
 185                         goto out_page;
 186                 }
 187                 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
 188                 if (f->metadata) {
 189                         jffs2_mark_node_obsolete(c, f->metadata->raw);
 190                         jffs2_free_full_dnode(f->metadata);
 191                         f->metadata = NULL;
 192                 }
 193                 if (ret) {
 194                         D1(printk(KERN_DEBUG "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", ret));
 195                         jffs2_mark_node_obsolete(c, fn->raw);
 196                         jffs2_free_full_dnode(fn);
 197                         jffs2_complete_reservation(c);
 198                         mutex_unlock(&f->sem);
 199                         goto out_page;
 200                 }
 201                 jffs2_complete_reservation(c);
 202                 inode->i_size = pageofs;
 203                 mutex_unlock(&f->sem);
 204         }
 205
 206         /*
 207          * Read in the page if it wasn't already present. Cannot optimize away
 208          * the whole page write case until jffs2_write_end can handle the
 209          * case of a short-copy.
 210          */
 211         if (!PageUptodate(pg)) {
 212                 mutex_lock(&f->sem);
 213                 ret = jffs2_do_readpage_nolock(inode, pg);
 214                 mutex_unlock(&f->sem);
 215                 if (ret)
 216                         goto out_page;
 217         }
 218         D1(printk(KERN_DEBUG "end write_begin(). pg->flags %lx\n", pg->flags));
 219         return ret;
 220
 221 out_page:
 222         unlock_page(pg);
 223         page_cache_release(pg);
 224         return ret;
 225 }
 226
 227 static int jffs2_write_end(struct file *filp, struct address_space *mapping,
 228                         loff_t pos, unsigned len, unsigned copied,
 229                         struct page *pg, void *fsdata)
 230 {
 231         /* Actually commit the write from the page cache page we're looking at.
 232          * For now, we write the full page out each time. It sucks, but it's simple
 233          */
 234         struct inode *inode = mapping->host;
 235         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 236         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 237         struct jffs2_raw_inode *ri;
 238         unsigned start = pos & (PAGE_CACHE_SIZE - 1);
 239         unsigned end = start + copied;
 240         unsigned aligned_start = start & ~3;
 241         int ret = 0;
 242         uint32_t writtenlen = 0;
 243
 244         D1(printk(KERN_DEBUG "jffs2_write_end(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
 245                   inode->i_ino, pg->index << PAGE_CACHE_SHIFT, start, end, pg->flags));
 246
 247         /* We need to avoid deadlock with page_cache_read() in
 248            jffs2_garbage_collect_pass(). So the page must be
 249            up to date to prevent page_cache_read() from trying
 250            to re-lock it. */
 251         BUG_ON(!PageUptodate(pg));
 252
 253         if (end == PAGE_CACHE_SIZE) {
 254                 /* When writing out the end of a page, write out the
 255                    _whole_ page. This helps to reduce the number of
 256                    nodes in files which have many short writes, like
 257                    syslog files. */
 258                 aligned_start = 0;
 259         }
 260
 261         ri = jffs2_alloc_raw_inode();
 262
 263         if (!ri) {
 264                 D1(printk(KERN_DEBUG "jffs2_write_end(): Allocation of raw inode failed\n"));
 265                 unlock_page(pg);
 266                 page_cache_release(pg);
 267                 return -ENOMEM;
 268         }
 269
 270         /* Set the fields that the generic jffs2_write_inode_range() code can't find */
 271         ri->ino = cpu_to_je32(inode->i_ino);
 272         ri->mode = cpu_to_jemode(inode->i_mode);
 273         ri->uid = cpu_to_je16(inode->i_uid);
 274         ri->gid = cpu_to_je16(inode->i_gid);
 275         ri->isize = cpu_to_je32((uint32_t)inode->i_size);
 276         ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds());
 277
 278         /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
 279            hurt to do it again. The alternative is ifdefs, which are ugly. */
 280         kmap(pg);
 281
 282         ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
 283                                       (pg->index << PAGE_CACHE_SHIFT) + aligned_start,
 284                                       end - aligned_start, &writtenlen);
 285
 286         kunmap(pg);
 287
 288         if (ret) {
 289                 /* There was an error writing. */
 290                 SetPageError(pg);
 291         }
 292
 293         /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
 294         writtenlen -= min(writtenlen, (start - aligned_start));
 295
 296         if (writtenlen) {
 297                 if (inode->i_size < pos + writtenlen) {
 298                         inode->i_size = pos + writtenlen;
 299                         inode->i_blocks = (inode->i_size + 511) >> 9;
 300
 301                         inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
 302                 }
 303         }
 304
 305         jffs2_free_raw_inode(ri);
 306
 307         if (start+writtenlen < end) {
 308                 /* generic_file_write has written more to the page cache than we've
 309                    actually written to the medium. Mark the page !Uptodate so that
 310                    it gets reread */
 311                 D1(printk(KERN_DEBUG "jffs2_write_end(): Not all bytes written. Marking page !uptodate\n"));
 312                 SetPageError(pg);
 313                 ClearPageUptodate(pg);
 314         }
 315
 316         D1(printk(KERN_DEBUG "jffs2_write_end() returning %d\n",
 317                                         writtenlen > 0 ? writtenlen : ret));
 318         unlock_page(pg);
 319         page_cache_release(pg);
 320         return writtenlen > 0 ? writtenlen : ret;
 321 }