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 1.102 2005/07/06 12:13:09 dwmw2 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 extern int generic_file_open(struct inode *, struct file *) __attribute__((weak));
  25 extern loff_t generic_file_llseek(struct file *file, loff_t offset, int origin) __attribute__((weak));
  26
  27 static int jffs2_commit_write (struct file *filp, struct page *pg,
  28                                unsigned start, unsigned end);
  29 static int jffs2_prepare_write (struct file *filp, struct page *pg,
  30                                 unsigned start, unsigned end);
  31 static int jffs2_readpage (struct file *filp, struct page *pg);
  32
  33 int jffs2_fsync(struct file *filp, struct dentry *dentry, int datasync)
  34 {
  35         struct inode *inode = dentry->d_inode;
  36         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
  37
  38         /* Trigger GC to flush any pending writes for this inode */
  39         jffs2_flush_wbuf_gc(c, inode->i_ino);
  40
  41         return 0;
  42 }
  43
  44 struct file_operations jffs2_file_operations =
  45 {
  46         .llseek =       generic_file_llseek,
  47         .open =         generic_file_open,
  48         .read =         generic_file_read,
  49         .write =        generic_file_write,
  50         .ioctl =        jffs2_ioctl,
  51         .mmap =         generic_file_readonly_mmap,
  52         .fsync =        jffs2_fsync,
  53         .sendfile =     generic_file_sendfile
  54 };
  55
  56 /* jffs2_file_inode_operations */
  57
  58 struct inode_operations jffs2_file_inode_operations =
  59 {
  60         .setattr =      jffs2_setattr
  61 };
  62
  63 struct address_space_operations jffs2_file_address_operations =
  64 {
  65         .readpage =     jffs2_readpage,
  66         .prepare_write =jffs2_prepare_write,
  67         .commit_write = jffs2_commit_write
  68 };
  69
  70 static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
  71 {
  72         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
  73         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
  74         unsigned char *pg_buf;
  75         int ret;
  76
  77         D2(printk(KERN_DEBUG "jffs2_do_readpage_nolock(): ino #%lu, page at offset 0x%lx\n", inode->i_ino, pg->index << PAGE_CACHE_SHIFT));
  78
  79         BUG_ON(!PageLocked(pg));
  80
  81         pg_buf = kmap(pg);
  82         /* FIXME: Can kmap fail? */
  83
  84         ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE);
  85
  86         if (ret) {
  87                 ClearPageUptodate(pg);
  88                 SetPageError(pg);
  89         } else {
  90                 SetPageUptodate(pg);
  91                 ClearPageError(pg);
  92         }
  93
  94         flush_dcache_page(pg);
  95         kunmap(pg);
  96
  97         D2(printk(KERN_DEBUG "readpage finished\n"));
  98         return 0;
  99 }
 100
 101 int jffs2_do_readpage_unlock(struct inode *inode, struct page *pg)
 102 {
 103         int ret = jffs2_do_readpage_nolock(inode, pg);
 104         unlock_page(pg);
 105         return ret;
 106 }
 107
 108
 109 static int jffs2_readpage (struct file *filp, struct page *pg)
 110 {
 111         struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
 112         int ret;
 113
 114         down(&f->sem);
 115         ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
 116         up(&f->sem);
 117         return ret;
 118 }
 119
 120 static int jffs2_prepare_write (struct file *filp, struct page *pg,
 121                                 unsigned start, unsigned end)
 122 {
 123         struct inode *inode = pg->mapping->host;
 124         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 125         uint32_t pageofs = pg->index << PAGE_CACHE_SHIFT;
 126         int ret = 0;
 127
 128         D1(printk(KERN_DEBUG "jffs2_prepare_write()\n"));
 129
 130         if (pageofs > inode->i_size) {
 131                 /* Make new hole frag from old EOF to new page */
 132                 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 133                 struct jffs2_raw_inode ri;
 134                 struct jffs2_full_dnode *fn;
 135                 uint32_t phys_ofs, alloc_len;
 136
 137                 D1(printk(KERN_DEBUG "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
 138                           (unsigned int)inode->i_size, pageofs));
 139
 140                 ret = jffs2_reserve_space(c, sizeof(ri), &phys_ofs, &alloc_len, ALLOC_NORMAL);
 141                 if (ret)
 142                         return ret;
 143
 144                 down(&f->sem);
 145                 memset(&ri, 0, sizeof(ri));
 146
 147                 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
 148                 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
 149                 ri.totlen = cpu_to_je32(sizeof(ri));
 150                 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
 151
 152                 ri.ino = cpu_to_je32(f->inocache->ino);
 153                 ri.version = cpu_to_je32(++f->highest_version);
 154                 ri.mode = cpu_to_jemode(inode->i_mode);
 155                 ri.uid = cpu_to_je16(inode->i_uid);
 156                 ri.gid = cpu_to_je16(inode->i_gid);
 157                 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
 158                 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());
 159                 ri.offset = cpu_to_je32(inode->i_size);
 160                 ri.dsize = cpu_to_je32(pageofs - inode->i_size);
 161                 ri.csize = cpu_to_je32(0);
 162                 ri.compr = JFFS2_COMPR_ZERO;
 163                 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
 164                 ri.data_crc = cpu_to_je32(0);
 165
 166                 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, phys_ofs, ALLOC_NORMAL);
 167
 168                 if (IS_ERR(fn)) {
 169                         ret = PTR_ERR(fn);
 170                         jffs2_complete_reservation(c);
 171                         up(&f->sem);
 172                         return ret;
 173                 }
 174                 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
 175                 if (f->metadata) {
 176                         jffs2_mark_node_obsolete(c, f->metadata->raw);
 177                         jffs2_free_full_dnode(f->metadata);
 178                         f->metadata = NULL;
 179                 }
 180                 if (ret) {
 181                         D1(printk(KERN_DEBUG "Eep. add_full_dnode_to_inode() failed in prepare_write, returned %d\n", ret));
 182                         jffs2_mark_node_obsolete(c, fn->raw);
 183                         jffs2_free_full_dnode(fn);
 184                         jffs2_complete_reservation(c);
 185                         up(&f->sem);
 186                         return ret;
 187                 }
 188                 jffs2_complete_reservation(c);
 189                 inode->i_size = pageofs;
 190                 up(&f->sem);
 191         }
 192
 193         /* Read in the page if it wasn't already present, unless it's a whole page */
 194         if (!PageUptodate(pg) && (start || end < PAGE_CACHE_SIZE)) {
 195                 down(&f->sem);
 196                 ret = jffs2_do_readpage_nolock(inode, pg);
 197                 up(&f->sem);
 198         }
 199         D1(printk(KERN_DEBUG "end prepare_write(). pg->flags %lx\n", pg->flags));
 200         return ret;
 201 }
 202
 203 static int jffs2_commit_write (struct file *filp, struct page *pg,
 204                                unsigned start, unsigned end)
 205 {
 206         /* Actually commit the write from the page cache page we're looking at.
 207          * For now, we write the full page out each time. It sucks, but it's simple
 208          */
 209         struct inode *inode = pg->mapping->host;
 210         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 211         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 212         struct jffs2_raw_inode *ri;
 213         unsigned aligned_start = start & ~3;
 214         int ret = 0;
 215         uint32_t writtenlen = 0;
 216
 217         D1(printk(KERN_DEBUG "jffs2_commit_write(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
 218                   inode->i_ino, pg->index << PAGE_CACHE_SHIFT, start, end, pg->flags));
 219
 220         if (!start && end == PAGE_CACHE_SIZE) {
 221                 /* We need to avoid deadlock with page_cache_read() in
 222                    jffs2_garbage_collect_pass(). So we have to mark the
 223                    page up to date, to prevent page_cache_read() from
 224                    trying to re-lock it. */
 225                 SetPageUptodate(pg);
 226         }
 227
 228         ri = jffs2_alloc_raw_inode();
 229
 230         if (!ri) {
 231                 D1(printk(KERN_DEBUG "jffs2_commit_write(): Allocation of raw inode failed\n"));
 232                 return -ENOMEM;
 233         }
 234
 235         /* Set the fields that the generic jffs2_write_inode_range() code can't find */
 236         ri->ino = cpu_to_je32(inode->i_ino);
 237         ri->mode = cpu_to_jemode(inode->i_mode);
 238         ri->uid = cpu_to_je16(inode->i_uid);
 239         ri->gid = cpu_to_je16(inode->i_gid);
 240         ri->isize = cpu_to_je32((uint32_t)inode->i_size);
 241         ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds());
 242
 243         /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
 244            hurt to do it again. The alternative is ifdefs, which are ugly. */
 245         kmap(pg);
 246
 247         ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
 248                                       (pg->index << PAGE_CACHE_SHIFT) + aligned_start,
 249                                       end - aligned_start, &writtenlen);
 250
 251         kunmap(pg);
 252
 253         if (ret) {
 254                 /* There was an error writing. */
 255                 SetPageError(pg);
 256         }
 257
 258         /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
 259         if (writtenlen < (start&3))
 260                 writtenlen = 0;
 261         else
 262                 writtenlen -= (start&3);
 263
 264         if (writtenlen) {
 265                 if (inode->i_size < (pg->index << PAGE_CACHE_SHIFT) + start + writtenlen) {
 266                         inode->i_size = (pg->index << PAGE_CACHE_SHIFT) + start + writtenlen;
 267                         inode->i_blocks = (inode->i_size + 511) >> 9;
 268
 269                         inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
 270                 }
 271         }
 272
 273         jffs2_free_raw_inode(ri);
 274
 275         if (start+writtenlen < end) {
 276                 /* generic_file_write has written more to the page cache than we've
 277                    actually written to the medium. Mark the page !Uptodate so that
 278                    it gets reread */
 279                 D1(printk(KERN_DEBUG "jffs2_commit_write(): Not all bytes written. Marking page !uptodate\n"));
 280                 SetPageError(pg);
 281                 ClearPageUptodate(pg);
 282         }
 283
 284         D1(printk(KERN_DEBUG "jffs2_commit_write() returning %d\n",writtenlen?writtenlen:ret));
 285         return writtenlen?writtenlen:ret;
 286 }