fs/jffs2/file.c

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright (C) 2001-2003 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  * $Id: file.c,v 1.99 2004/11/16 20:36:11 dwmw2 Exp $
  11  *
  12  */
  13
  14 #include <linux/version.h>
  15 #include <linux/kernel.h>
  16 #include <linux/slab.h>
  17 #include <linux/fs.h>
  18 #include <linux/time.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/highmem.h>
  21 #include <linux/crc32.h>
  22 #include <linux/jffs2.h>
  23 #include "nodelist.h"
  24
  25 extern int generic_file_open(struct inode *, struct file *) __attribute__((weak));
  26 extern loff_t generic_file_llseek(struct file *file, loff_t offset, int origin) __attribute__((weak));
  27
  28 static int jffs2_commit_write (struct file *filp, struct page *pg,
  29                                unsigned start, unsigned end);
  30 static int jffs2_prepare_write (struct file *filp, struct page *pg,
  31                                 unsigned start, unsigned end);
  32 static int jffs2_readpage (struct file *filp, struct page *pg);
  33
  34 int jffs2_fsync(struct file *filp, struct dentry *dentry, int datasync)
  35 {
  36         struct inode *inode = dentry->d_inode;
  37         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
  38
  39         /* Trigger GC to flush any pending writes for this inode */
  40         jffs2_flush_wbuf_gc(c, inode->i_ino);
  41
  42         return 0;
  43 }
  44
  45 struct file_operations jffs2_file_operations =
  46 {
  47         .llseek =       generic_file_llseek,
  48         .open =         generic_file_open,
  49         .read =         generic_file_read,
  50         .write =        generic_file_write,
  51         .ioctl =        jffs2_ioctl,
  52         .mmap =         generic_file_readonly_mmap,
  53         .fsync =        jffs2_fsync,
  54 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,29)
  55         .sendfile =     generic_file_sendfile
  56 #endif
  57 };
  58
  59 /* jffs2_file_inode_operations */
  60
  61 struct inode_operations jffs2_file_inode_operations =
  62 {
  63         .setattr =      jffs2_setattr
  64 };
  65
  66 struct address_space_operations jffs2_file_address_operations =
  67 {
  68         .readpage =     jffs2_readpage,
  69         .prepare_write =jffs2_prepare_write,
  70         .commit_write = jffs2_commit_write
  71 };
  72
  73 static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
  74 {
  75         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
  76         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
  77         unsigned char *pg_buf;
  78         int ret;
  79
  80         D2(printk(KERN_DEBUG "jffs2_do_readpage_nolock(): ino #%lu, page at offset 0x%lx\n", inode->i_ino, pg->index << PAGE_CACHE_SHIFT));
  81
  82         if (!PageLocked(pg))
  83                 PAGE_BUG(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         down(&f->sem);
 119         ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
 120         up(&f->sem);
 121         return ret;
 122 }
 123
 124 static int jffs2_prepare_write (struct file *filp, struct page *pg,
 125                                 unsigned start, unsigned end)
 126 {
 127         struct inode *inode = pg->mapping->host;
 128         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 129         uint32_t pageofs = pg->index << PAGE_CACHE_SHIFT;
 130         int ret = 0;
 131
 132         D1(printk(KERN_DEBUG "jffs2_prepare_write()\n"));
 133
 134         if (pageofs > inode->i_size) {
 135                 /* Make new hole frag from old EOF to new page */
 136                 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 137                 struct jffs2_raw_inode ri;
 138                 struct jffs2_full_dnode *fn;
 139                 uint32_t phys_ofs, alloc_len;
 140
 141                 D1(printk(KERN_DEBUG "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
 142                           (unsigned int)inode->i_size, pageofs));
 143
 144                 ret = jffs2_reserve_space(c, sizeof(ri), &phys_ofs, &alloc_len, ALLOC_NORMAL);
 145                 if (ret)
 146                         return ret;
 147
 148                 down(&f->sem);
 149                 memset(&ri, 0, sizeof(ri));
 150
 151                 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
 152                 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
 153                 ri.totlen = cpu_to_je32(sizeof(ri));
 154                 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
 155
 156                 ri.ino = cpu_to_je32(f->inocache->ino);
 157                 ri.version = cpu_to_je32(++f->highest_version);
 158                 ri.mode = cpu_to_jemode(inode->i_mode);
 159                 ri.uid = cpu_to_je16(inode->i_uid);
 160                 ri.gid = cpu_to_je16(inode->i_gid);
 161                 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
 162                 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());
 163                 ri.offset = cpu_to_je32(inode->i_size);
 164                 ri.dsize = cpu_to_je32(pageofs - inode->i_size);
 165                 ri.csize = cpu_to_je32(0);
 166                 ri.compr = JFFS2_COMPR_ZERO;
 167                 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
 168                 ri.data_crc = cpu_to_je32(0);
 169
 170                 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, phys_ofs, ALLOC_NORMAL);
 171
 172                 if (IS_ERR(fn)) {
 173                         ret = PTR_ERR(fn);
 174                         jffs2_complete_reservation(c);
 175                         up(&f->sem);
 176                         return ret;
 177                 }
 178                 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
 179                 if (f->metadata) {
 180                         jffs2_mark_node_obsolete(c, f->metadata->raw);
 181                         jffs2_free_full_dnode(f->metadata);
 182                         f->metadata = NULL;
 183                 }
 184                 if (ret) {
 185                         D1(printk(KERN_DEBUG "Eep. add_full_dnode_to_inode() failed in prepare_write, returned %d\n", ret));
 186                         jffs2_mark_node_obsolete(c, fn->raw);
 187                         jffs2_free_full_dnode(fn);
 188                         jffs2_complete_reservation(c);
 189                         up(&f->sem);
 190                         return ret;
 191                 }
 192                 jffs2_complete_reservation(c);
 193                 inode->i_size = pageofs;
 194                 up(&f->sem);
 195         }
 196
 197         /* Read in the page if it wasn't already present, unless it's a whole page */
 198         if (!PageUptodate(pg) && (start || end < PAGE_CACHE_SIZE)) {
 199                 down(&f->sem);
 200                 ret = jffs2_do_readpage_nolock(inode, pg);
 201                 up(&f->sem);
 202         }
 203         D1(printk(KERN_DEBUG "end prepare_write(). pg->flags %lx\n", pg->flags));
 204         return ret;
 205 }
 206
 207 static int jffs2_commit_write (struct file *filp, struct page *pg,
 208                                unsigned start, unsigned end)
 209 {
 210         /* Actually commit the write from the page cache page we're looking at.
 211          * For now, we write the full page out each time. It sucks, but it's simple
 212          */
 213         struct inode *inode = pg->mapping->host;
 214         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 215         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 216         struct jffs2_raw_inode *ri;
 217         unsigned aligned_start = start & ~3;
 218         int ret = 0;
 219         uint32_t writtenlen = 0;
 220
 221         D1(printk(KERN_DEBUG "jffs2_commit_write(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
 222                   inode->i_ino, pg->index << PAGE_CACHE_SHIFT, start, end, pg->flags));
 223
 224         if (!start && end == PAGE_CACHE_SIZE) {
 225                 /* We need to avoid deadlock with page_cache_read() in
 226                    jffs2_garbage_collect_pass(). So we have to mark the
 227                    page up to date, to prevent page_cache_read() from
 228                    trying to re-lock it. */
 229                 SetPageUptodate(pg);
 230         }
 231
 232         ri = jffs2_alloc_raw_inode();
 233
 234         if (!ri) {
 235                 D1(printk(KERN_DEBUG "jffs2_commit_write(): Allocation of raw inode failed\n"));
 236                 return -ENOMEM;
 237         }
 238
 239         /* Set the fields that the generic jffs2_write_inode_range() code can't find */
 240         ri->ino = cpu_to_je32(inode->i_ino);
 241         ri->mode = cpu_to_jemode(inode->i_mode);
 242         ri->uid = cpu_to_je16(inode->i_uid);
 243         ri->gid = cpu_to_je16(inode->i_gid);
 244         ri->isize = cpu_to_je32((uint32_t)inode->i_size);
 245         ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds());
 246
 247         /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
 248            hurt to do it again. The alternative is ifdefs, which are ugly. */
 249         kmap(pg);
 250
 251         ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
 252                                       (pg->index << PAGE_CACHE_SHIFT) + aligned_start,
 253                                       end - aligned_start, &writtenlen);
 254
 255         kunmap(pg);
 256
 257         if (ret) {
 258                 /* There was an error writing. */
 259                 SetPageError(pg);
 260         }
 261
 262         /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
 263         if (writtenlen < (start&3))
 264                 writtenlen = 0;
 265         else
 266                 writtenlen -= (start&3);
 267
 268         if (writtenlen) {
 269                 if (inode->i_size < (pg->index << PAGE_CACHE_SHIFT) + start + writtenlen) {
 270                         inode->i_size = (pg->index << PAGE_CACHE_SHIFT) + start + writtenlen;
 271                         inode->i_blocks = (inode->i_size + 511) >> 9;
 272
 273                         inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
 274                 }
 275         }
 276
 277         jffs2_free_raw_inode(ri);
 278
 279         if (start+writtenlen < end) {
 280                 /* generic_file_write has written more to the page cache than we've
 281                    actually written to the medium. Mark the page !Uptodate so that
 282                    it gets reread */
 283                 D1(printk(KERN_DEBUG "jffs2_commit_write(): Not all bytes written. Marking page !uptodate\n"));
 284                 SetPageError(pg);
 285                 ClearPageUptodate(pg);
 286         }
 287
 288         D1(printk(KERN_DEBUG "jffs2_commit_write() returning %d\n",writtenlen?writtenlen:ret));
 289         return writtenlen?writtenlen:ret;
 290 }