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 =         do_sync_read,
  46         .aio_read =     generic_file_aio_read,
  47         .write =        do_sync_write,
  48         .aio_write =    generic_file_aio_write,
  49         .ioctl =        jffs2_ioctl,
  50         .mmap =         generic_file_readonly_mmap,
  51         .fsync =        jffs2_fsync,
  52         .sendfile =     generic_file_sendfile
  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         .prepare_write =jffs2_prepare_write,
  71         .commit_write = jffs2_commit_write
  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         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 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), &alloc_len,
 145                                           ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
 146                 if (ret)
 147                         return ret;
 148
 149                 down(&f->sem);
 150                 memset(&ri, 0, sizeof(ri));
 151
 152                 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
 153                 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
 154                 ri.totlen = cpu_to_je32(sizeof(ri));
 155                 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
 156
 157                 ri.ino = cpu_to_je32(f->inocache->ino);
 158                 ri.version = cpu_to_je32(++f->highest_version);
 159                 ri.mode = cpu_to_jemode(inode->i_mode);
 160                 ri.uid = cpu_to_je16(inode->i_uid);
 161                 ri.gid = cpu_to_je16(inode->i_gid);
 162                 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
 163                 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());
 164                 ri.offset = cpu_to_je32(inode->i_size);
 165                 ri.dsize = cpu_to_je32(pageofs - inode->i_size);
 166                 ri.csize = cpu_to_je32(0);
 167                 ri.compr = JFFS2_COMPR_ZERO;
 168                 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
 169                 ri.data_crc = cpu_to_je32(0);
 170
 171                 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
 172
 173                 if (IS_ERR(fn)) {
 174                         ret = PTR_ERR(fn);
 175                         jffs2_complete_reservation(c);
 176                         up(&f->sem);
 177                         return ret;
 178                 }
 179                 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
 180                 if (f->metadata) {
 181                         jffs2_mark_node_obsolete(c, f->metadata->raw);
 182                         jffs2_free_full_dnode(f->metadata);
 183                         f->metadata = NULL;
 184                 }
 185                 if (ret) {
 186                         D1(printk(KERN_DEBUG "Eep. add_full_dnode_to_inode() failed in prepare_write, returned %d\n", ret));
 187                         jffs2_mark_node_obsolete(c, fn->raw);
 188                         jffs2_free_full_dnode(fn);
 189                         jffs2_complete_reservation(c);
 190                         up(&f->sem);
 191                         return ret;
 192                 }
 193                 jffs2_complete_reservation(c);
 194                 inode->i_size = pageofs;
 195                 up(&f->sem);
 196         }
 197
 198         /* Read in the page if it wasn't already present, unless it's a whole page */
 199         if (!PageUptodate(pg) && (start || end < PAGE_CACHE_SIZE)) {
 200                 down(&f->sem);
 201                 ret = jffs2_do_readpage_nolock(inode, pg);
 202                 up(&f->sem);
 203         }
 204         D1(printk(KERN_DEBUG "end prepare_write(). pg->flags %lx\n", pg->flags));
 205         return ret;
 206 }
 207
 208 static int jffs2_commit_write (struct file *filp, struct page *pg,
 209                                unsigned start, unsigned end)
 210 {
 211         /* Actually commit the write from the page cache page we're looking at.
 212          * For now, we write the full page out each time. It sucks, but it's simple
 213          */
 214         struct inode *inode = pg->mapping->host;
 215         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 216         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 217         struct jffs2_raw_inode *ri;
 218         unsigned aligned_start = start & ~3;
 219         int ret = 0;
 220         uint32_t writtenlen = 0;
 221
 222         D1(printk(KERN_DEBUG "jffs2_commit_write(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
 223                   inode->i_ino, pg->index << PAGE_CACHE_SHIFT, start, end, pg->flags));
 224
 225         if (end == PAGE_CACHE_SIZE) {
 226                 if (!start) {
 227                         /* We need to avoid deadlock with page_cache_read() in
 228                            jffs2_garbage_collect_pass(). So we have to mark the
 229                            page up to date, to prevent page_cache_read() from
 230                            trying to re-lock it. */
 231                         SetPageUptodate(pg);
 232                 } else {
 233                         /* When writing out the end of a page, write out the
 234                            _whole_ page. This helps to reduce the number of
 235                            nodes in files which have many short writes, like
 236                            syslog files. */
 237                         start = aligned_start = 0;
 238                 }
 239         }
 240
 241         ri = jffs2_alloc_raw_inode();
 242
 243         if (!ri) {
 244                 D1(printk(KERN_DEBUG "jffs2_commit_write(): Allocation of raw inode failed\n"));
 245                 return -ENOMEM;
 246         }
 247
 248         /* Set the fields that the generic jffs2_write_inode_range() code can't find */
 249         ri->ino = cpu_to_je32(inode->i_ino);
 250         ri->mode = cpu_to_jemode(inode->i_mode);
 251         ri->uid = cpu_to_je16(inode->i_uid);
 252         ri->gid = cpu_to_je16(inode->i_gid);
 253         ri->isize = cpu_to_je32((uint32_t)inode->i_size);
 254         ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds());
 255
 256         /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
 257            hurt to do it again. The alternative is ifdefs, which are ugly. */
 258         kmap(pg);
 259
 260         ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
 261                                       (pg->index << PAGE_CACHE_SHIFT) + aligned_start,
 262                                       end - aligned_start, &writtenlen);
 263
 264         kunmap(pg);
 265
 266         if (ret) {
 267                 /* There was an error writing. */
 268                 SetPageError(pg);
 269         }
 270
 271         /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
 272         if (writtenlen < (start&3))
 273                 writtenlen = 0;
 274         else
 275                 writtenlen -= (start&3);
 276
 277         if (writtenlen) {
 278                 if (inode->i_size < (pg->index << PAGE_CACHE_SHIFT) + start + writtenlen) {
 279                         inode->i_size = (pg->index << PAGE_CACHE_SHIFT) + start + writtenlen;
 280                         inode->i_blocks = (inode->i_size + 511) >> 9;
 281
 282                         inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
 283                 }
 284         }
 285
 286         jffs2_free_raw_inode(ri);
 287
 288         if (start+writtenlen < end) {
 289                 /* generic_file_write has written more to the page cache than we've
 290                    actually written to the medium. Mark the page !Uptodate so that
 291                    it gets reread */
 292                 D1(printk(KERN_DEBUG "jffs2_commit_write(): Not all bytes written. Marking page !uptodate\n"));
 293                 SetPageError(pg);
 294                 ClearPageUptodate(pg);
 295         }
 296
 297         D1(printk(KERN_DEBUG "jffs2_commit_write() returning %d\n",start+writtenlen==end?0:ret));
 298         return start+writtenlen==end?0:ret;
 299 }