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         BUG_ON(!PageLocked(pg));
  83
  84         pg_buf = kmap(pg);
  85         /* FIXME: Can kmap fail? */
  86
  87         ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE);
  88
  89         if (ret) {
  90                 ClearPageUptodate(pg);
  91                 SetPageError(pg);
  92         } else {
  93                 SetPageUptodate(pg);
  94                 ClearPageError(pg);
  95         }
  96
  97         flush_dcache_page(pg);
  98         kunmap(pg);
  99
 100         D2(printk(KERN_DEBUG "readpage finished\n"));
 101         return 0;
 102 }
 103
 104 int jffs2_do_readpage_unlock(struct inode *inode, struct page *pg)
 105 {
 106         int ret = jffs2_do_readpage_nolock(inode, pg);
 107         unlock_page(pg);
 108         return ret;
 109 }
 110
 111
 112 static int jffs2_readpage (struct file *filp, struct page *pg)
 113 {
 114         struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
 115         int ret;
 116
 117         down(&f->sem);
 118         ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
 119         up(&f->sem);
 120         return ret;
 121 }
 122
 123 static int jffs2_prepare_write (struct file *filp, struct page *pg,
 124                                 unsigned start, unsigned end)
 125 {
 126         struct inode *inode = pg->mapping->host;
 127         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 128         uint32_t pageofs = pg->index << PAGE_CACHE_SHIFT;
 129         int ret = 0;
 130
 131         D1(printk(KERN_DEBUG "jffs2_prepare_write()\n"));
 132
 133         if (pageofs > inode->i_size) {
 134                 /* Make new hole frag from old EOF to new page */
 135                 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 136                 struct jffs2_raw_inode ri;
 137                 struct jffs2_full_dnode *fn;
 138                 uint32_t phys_ofs, alloc_len;
 139
 140                 D1(printk(KERN_DEBUG "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
 141                           (unsigned int)inode->i_size, pageofs));
 142
 143                 ret = jffs2_reserve_space(c, sizeof(ri), &phys_ofs, &alloc_len, ALLOC_NORMAL);
 144                 if (ret)
 145                         return ret;
 146
 147                 down(&f->sem);
 148                 memset(&ri, 0, sizeof(ri));
 149
 150                 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
 151                 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
 152                 ri.totlen = cpu_to_je32(sizeof(ri));
 153                 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
 154
 155                 ri.ino = cpu_to_je32(f->inocache->ino);
 156                 ri.version = cpu_to_je32(++f->highest_version);
 157                 ri.mode = cpu_to_jemode(inode->i_mode);
 158                 ri.uid = cpu_to_je16(inode->i_uid);
 159                 ri.gid = cpu_to_je16(inode->i_gid);
 160                 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
 161                 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());
 162                 ri.offset = cpu_to_je32(inode->i_size);
 163                 ri.dsize = cpu_to_je32(pageofs - inode->i_size);
 164                 ri.csize = cpu_to_je32(0);
 165                 ri.compr = JFFS2_COMPR_ZERO;
 166                 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
 167                 ri.data_crc = cpu_to_je32(0);
 168
 169                 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, phys_ofs, ALLOC_NORMAL);
 170
 171                 if (IS_ERR(fn)) {
 172                         ret = PTR_ERR(fn);
 173                         jffs2_complete_reservation(c);
 174                         up(&f->sem);
 175                         return ret;
 176                 }
 177                 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
 178                 if (f->metadata) {
 179                         jffs2_mark_node_obsolete(c, f->metadata->raw);
 180                         jffs2_free_full_dnode(f->metadata);
 181                         f->metadata = NULL;
 182                 }
 183                 if (ret) {
 184                         D1(printk(KERN_DEBUG "Eep. add_full_dnode_to_inode() failed in prepare_write, returned %d\n", ret));
 185                         jffs2_mark_node_obsolete(c, fn->raw);
 186                         jffs2_free_full_dnode(fn);
 187                         jffs2_complete_reservation(c);
 188                         up(&f->sem);
 189                         return ret;
 190                 }
 191                 jffs2_complete_reservation(c);
 192                 inode->i_size = pageofs;
 193                 up(&f->sem);
 194         }
 195
 196         /* Read in the page if it wasn't already present, unless it's a whole page */
 197         if (!PageUptodate(pg) && (start || end < PAGE_CACHE_SIZE)) {
 198                 down(&f->sem);
 199                 ret = jffs2_do_readpage_nolock(inode, pg);
 200                 up(&f->sem);
 201         }
 202         D1(printk(KERN_DEBUG "end prepare_write(). pg->flags %lx\n", pg->flags));
 203         return ret;
 204 }
 205
 206 static int jffs2_commit_write (struct file *filp, struct page *pg,
 207                                unsigned start, unsigned end)
 208 {
 209         /* Actually commit the write from the page cache page we're looking at.
 210          * For now, we write the full page out each time. It sucks, but it's simple
 211          */
 212         struct inode *inode = pg->mapping->host;
 213         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 214         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 215         struct jffs2_raw_inode *ri;
 216         unsigned aligned_start = start & ~3;
 217         int ret = 0;
 218         uint32_t writtenlen = 0;
 219
 220         D1(printk(KERN_DEBUG "jffs2_commit_write(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
 221                   inode->i_ino, pg->index << PAGE_CACHE_SHIFT, start, end, pg->flags));
 222
 223         if (!start && end == PAGE_CACHE_SIZE) {
 224                 /* We need to avoid deadlock with page_cache_read() in
 225                    jffs2_garbage_collect_pass(). So we have to mark the
 226                    page up to date, to prevent page_cache_read() from
 227                    trying to re-lock it. */
 228                 SetPageUptodate(pg);
 229         }
 230
 231         ri = jffs2_alloc_raw_inode();
 232
 233         if (!ri) {
 234                 D1(printk(KERN_DEBUG "jffs2_commit_write(): Allocation of raw inode failed\n"));
 235                 return -ENOMEM;
 236         }
 237
 238         /* Set the fields that the generic jffs2_write_inode_range() code can't find */
 239         ri->ino = cpu_to_je32(inode->i_ino);
 240         ri->mode = cpu_to_jemode(inode->i_mode);
 241         ri->uid = cpu_to_je16(inode->i_uid);
 242         ri->gid = cpu_to_je16(inode->i_gid);
 243         ri->isize = cpu_to_je32((uint32_t)inode->i_size);
 244         ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds());
 245
 246         /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
 247            hurt to do it again. The alternative is ifdefs, which are ugly. */
 248         kmap(pg);
 249
 250         ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
 251                                       (pg->index << PAGE_CACHE_SHIFT) + aligned_start,
 252                                       end - aligned_start, &writtenlen);
 253
 254         kunmap(pg);
 255
 256         if (ret) {
 257                 /* There was an error writing. */
 258                 SetPageError(pg);
 259         }
 260
 261         /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
 262         if (writtenlen < (start&3))
 263                 writtenlen = 0;
 264         else
 265                 writtenlen -= (start&3);
 266
 267         if (writtenlen) {
 268                 if (inode->i_size < (pg->index << PAGE_CACHE_SHIFT) + start + writtenlen) {
 269                         inode->i_size = (pg->index << PAGE_CACHE_SHIFT) + start + writtenlen;
 270                         inode->i_blocks = (inode->i_size + 511) >> 9;
 271
 272                         inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
 273                 }
 274         }
 275
 276         jffs2_free_raw_inode(ri);
 277
 278         if (start+writtenlen < end) {
 279                 /* generic_file_write has written more to the page cache than we've
 280                    actually written to the medium. Mark the page !Uptodate so that
 281                    it gets reread */
 282                 D1(printk(KERN_DEBUG "jffs2_commit_write(): Not all bytes written. Marking page !uptodate\n"));
 283                 SetPageError(pg);
 284                 ClearPageUptodate(pg);
 285         }
 286
 287         D1(printk(KERN_DEBUG "jffs2_commit_write() returning %d\n",writtenlen?writtenlen:ret));
 288         return writtenlen?writtenlen:ret;
 289 }