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 1.104 2005/10/18 23:29:35 tpoynor Exp $
  11  *
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/slab.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_commit_write (struct file *filp, struct page *pg,
  25                                unsigned start, unsigned end);
  26 static int jffs2_prepare_write (struct file *filp, struct page *pg,
  27                                 unsigned start, unsigned end);
  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 =         generic_file_read,
  46         .write =        generic_file_write,
  47         .ioctl =        jffs2_ioctl,
  48         .mmap =         generic_file_readonly_mmap,
  49         .fsync =        jffs2_fsync,
  50         .sendfile =     generic_file_sendfile
  51 };
  52
  53 /* jffs2_file_inode_operations */
  54
  55 struct inode_operations jffs2_file_inode_operations =
  56 {
  57         .setattr =      jffs2_setattr
  58 };
  59
  60 struct address_space_operations jffs2_file_address_operations =
  61 {
  62         .readpage =     jffs2_readpage,
  63         .prepare_write =jffs2_prepare_write,
  64         .commit_write = jffs2_commit_write
  65 };
  66
  67 static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
  68 {
  69         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
  70         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
  71         unsigned char *pg_buf;
  72         int ret;
  73
  74         D2(printk(KERN_DEBUG "jffs2_do_readpage_nolock(): ino #%lu, page at offset 0x%lx\n", inode->i_ino, pg->index << PAGE_CACHE_SHIFT));
  75
  76         BUG_ON(!PageLocked(pg));
  77
  78         pg_buf = kmap(pg);
  79         /* FIXME: Can kmap fail? */
  80
  81         ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE);
  82
  83         if (ret) {
  84                 ClearPageUptodate(pg);
  85                 SetPageError(pg);
  86         } else {
  87                 SetPageUptodate(pg);
  88                 ClearPageError(pg);
  89         }
  90
  91         flush_dcache_page(pg);
  92         kunmap(pg);
  93
  94         D2(printk(KERN_DEBUG "readpage finished\n"));
  95         return 0;
  96 }
  97
  98 int jffs2_do_readpage_unlock(struct inode *inode, struct page *pg)
  99 {
 100         int ret = jffs2_do_readpage_nolock(inode, pg);
 101         unlock_page(pg);
 102         return ret;
 103 }
 104
 105
 106 static int jffs2_readpage (struct file *filp, struct page *pg)
 107 {
 108         struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
 109         int ret;
 110
 111         down(&f->sem);
 112         ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
 113         up(&f->sem);
 114         return ret;
 115 }
 116
 117 static int jffs2_prepare_write (struct file *filp, struct page *pg,
 118                                 unsigned start, unsigned end)
 119 {
 120         struct inode *inode = pg->mapping->host;
 121         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 122         uint32_t pageofs = pg->index << PAGE_CACHE_SHIFT;
 123         int ret = 0;
 124
 125         D1(printk(KERN_DEBUG "jffs2_prepare_write()\n"));
 126
 127         if (pageofs > inode->i_size) {
 128                 /* Make new hole frag from old EOF to new page */
 129                 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 130                 struct jffs2_raw_inode ri;
 131                 struct jffs2_full_dnode *fn;
 132                 uint32_t phys_ofs, alloc_len;
 133
 134                 D1(printk(KERN_DEBUG "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
 135                           (unsigned int)inode->i_size, pageofs));
 136
 137                 ret = jffs2_reserve_space(c, sizeof(ri), &phys_ofs, &alloc_len,
 138                                         ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
 139                 if (ret)
 140                         return ret;
 141
 142                 down(&f->sem);
 143                 memset(&ri, 0, sizeof(ri));
 144
 145                 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
 146                 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
 147                 ri.totlen = cpu_to_je32(sizeof(ri));
 148                 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
 149
 150                 ri.ino = cpu_to_je32(f->inocache->ino);
 151                 ri.version = cpu_to_je32(++f->highest_version);
 152                 ri.mode = cpu_to_jemode(inode->i_mode);
 153                 ri.uid = cpu_to_je16(inode->i_uid);
 154                 ri.gid = cpu_to_je16(inode->i_gid);
 155                 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
 156                 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());
 157                 ri.offset = cpu_to_je32(inode->i_size);
 158                 ri.dsize = cpu_to_je32(pageofs - inode->i_size);
 159                 ri.csize = cpu_to_je32(0);
 160                 ri.compr = JFFS2_COMPR_ZERO;
 161                 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
 162                 ri.data_crc = cpu_to_je32(0);
 163
 164                 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, phys_ofs, ALLOC_NORMAL);
 165
 166                 if (IS_ERR(fn)) {
 167                         ret = PTR_ERR(fn);
 168                         jffs2_complete_reservation(c);
 169                         up(&f->sem);
 170                         return ret;
 171                 }
 172                 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
 173                 if (f->metadata) {
 174                         jffs2_mark_node_obsolete(c, f->metadata->raw);
 175                         jffs2_free_full_dnode(f->metadata);
 176                         f->metadata = NULL;
 177                 }
 178                 if (ret) {
 179                         D1(printk(KERN_DEBUG "Eep. add_full_dnode_to_inode() failed in prepare_write, returned %d\n", ret));
 180                         jffs2_mark_node_obsolete(c, fn->raw);
 181                         jffs2_free_full_dnode(fn);
 182                         jffs2_complete_reservation(c);
 183                         up(&f->sem);
 184                         return ret;
 185                 }
 186                 jffs2_complete_reservation(c);
 187                 inode->i_size = pageofs;
 188                 up(&f->sem);
 189         }
 190
 191         /* Read in the page if it wasn't already present, unless it's a whole page */
 192         if (!PageUptodate(pg) && (start || end < PAGE_CACHE_SIZE)) {
 193                 down(&f->sem);
 194                 ret = jffs2_do_readpage_nolock(inode, pg);
 195                 up(&f->sem);
 196         }
 197         D1(printk(KERN_DEBUG "end prepare_write(). pg->flags %lx\n", pg->flags));
 198         return ret;
 199 }
 200
 201 static int jffs2_commit_write (struct file *filp, struct page *pg,
 202                                unsigned start, unsigned end)
 203 {
 204         /* Actually commit the write from the page cache page we're looking at.
 205          * For now, we write the full page out each time. It sucks, but it's simple
 206          */
 207         struct inode *inode = pg->mapping->host;
 208         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 209         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 210         struct jffs2_raw_inode *ri;
 211         unsigned aligned_start = start & ~3;
 212         int ret = 0;
 213         uint32_t writtenlen = 0;
 214
 215         D1(printk(KERN_DEBUG "jffs2_commit_write(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
 216                   inode->i_ino, pg->index << PAGE_CACHE_SHIFT, start, end, pg->flags));
 217
 218         if (!start && end == PAGE_CACHE_SIZE) {
 219                 /* We need to avoid deadlock with page_cache_read() in
 220                    jffs2_garbage_collect_pass(). So we have to mark the
 221                    page up to date, to prevent page_cache_read() from
 222                    trying to re-lock it. */
 223                 SetPageUptodate(pg);
 224         }
 225
 226         ri = jffs2_alloc_raw_inode();
 227
 228         if (!ri) {
 229                 D1(printk(KERN_DEBUG "jffs2_commit_write(): Allocation of raw inode failed\n"));
 230                 return -ENOMEM;
 231         }
 232
 233         /* Set the fields that the generic jffs2_write_inode_range() code can't find */
 234         ri->ino = cpu_to_je32(inode->i_ino);
 235         ri->mode = cpu_to_jemode(inode->i_mode);
 236         ri->uid = cpu_to_je16(inode->i_uid);
 237         ri->gid = cpu_to_je16(inode->i_gid);
 238         ri->isize = cpu_to_je32((uint32_t)inode->i_size);
 239         ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds());
 240
 241         /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
 242            hurt to do it again. The alternative is ifdefs, which are ugly. */
 243         kmap(pg);
 244
 245         ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
 246                                       (pg->index << PAGE_CACHE_SHIFT) + aligned_start,
 247                                       end - aligned_start, &writtenlen);
 248
 249         kunmap(pg);
 250
 251         if (ret) {
 252                 /* There was an error writing. */
 253                 SetPageError(pg);
 254         }
 255
 256         /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
 257         if (writtenlen < (start&3))
 258                 writtenlen = 0;
 259         else
 260                 writtenlen -= (start&3);
 261
 262         if (writtenlen) {
 263                 if (inode->i_size < (pg->index << PAGE_CACHE_SHIFT) + start + writtenlen) {
 264                         inode->i_size = (pg->index << PAGE_CACHE_SHIFT) + start + writtenlen;
 265                         inode->i_blocks = (inode->i_size + 511) >> 9;
 266
 267                         inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
 268                 }
 269         }
 270
 271         jffs2_free_raw_inode(ri);
 272
 273         if (start+writtenlen < end) {
 274                 /* generic_file_write has written more to the page cache than we've
 275                    actually written to the medium. Mark the page !Uptodate so that
 276                    it gets reread */
 277                 D1(printk(KERN_DEBUG "jffs2_commit_write(): Not all bytes written. Marking page !uptodate\n"));
 278                 SetPageError(pg);
 279                 ClearPageUptodate(pg);
 280         }
 281
 282         D1(printk(KERN_DEBUG "jffs2_commit_write() returning %d\n",start+writtenlen==end?0:ret));
 283         return start+writtenlen==end?0:ret;
 284 }