fs/jffs2/file.c

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright © 2001-2007 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  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/fs.h>
  14 #include <linux/time.h>
  15 #include <linux/pagemap.h>
  16 #include <linux/highmem.h>
  17 #include <linux/crc32.h>
  18 #include <linux/jffs2.h>
  19 #include "nodelist.h"
  20
  21 static int jffs2_write_end(struct file *filp, struct address_space *mapping,
  22                         loff_t pos, unsigned len, unsigned copied,
  23                         struct page *pg, void *fsdata);
  24 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
  25                         loff_t pos, unsigned len, unsigned flags,
  26                         struct page **pagep, void **fsdata);
  27 static int jffs2_readpage (struct file *filp, struct page *pg);
  28
  29 int jffs2_fsync(struct file *filp, struct dentry *dentry, int datasync)
  30 {
  31         struct inode *inode = dentry->d_inode;
  32         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
  33
  34         /* Trigger GC to flush any pending writes for this inode */
  35         jffs2_flush_wbuf_gc(c, inode->i_ino);
  36
  37         return 0;
  38 }
  39
  40 const struct file_operations jffs2_file_operations =
  41 {
  42         .llseek =       generic_file_llseek,
  43         .open =         generic_file_open,
  44         .read =         do_sync_read,
  45         .aio_read =     generic_file_aio_read,
  46         .write =        do_sync_write,
  47         .aio_write =    generic_file_aio_write,
  48         .unlocked_ioctl=jffs2_ioctl,
  49         .mmap =         generic_file_readonly_mmap,
  50         .fsync =        jffs2_fsync,
  51         .splice_read =  generic_file_splice_read,
  52 };
  53
  54 /* jffs2_file_inode_operations */
  55
  56 const struct inode_operations jffs2_file_inode_operations =
  57 {
  58         .check_acl =    jffs2_check_acl,
  59         .setattr =      jffs2_setattr,
  60         .setxattr =     jffs2_setxattr,
  61         .getxattr =     jffs2_getxattr,
  62         .listxattr =    jffs2_listxattr,
  63         .removexattr =  jffs2_removexattr
  64 };
  65
  66 const struct address_space_operations jffs2_file_address_operations =
  67 {
  68         .readpage =     jffs2_readpage,
  69         .write_begin =  jffs2_write_begin,
  70         .write_end =    jffs2_write_end,
  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 ret;
 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         mutex_lock(&f->sem);
 118         ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
 119         mutex_unlock(&f->sem);
 120         return ret;
 121 }
 122
 123 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
 124                         loff_t pos, unsigned len, unsigned flags,
 125                         struct page **pagep, void **fsdata)
 126 {
 127         struct page *pg;
 128         struct inode *inode = mapping->host;
 129         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 130         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 131         uint32_t pageofs = index << PAGE_CACHE_SHIFT;
 132         int ret = 0;
 133
 134         pg = grab_cache_page_write_begin(mapping, index, flags);
 135         if (!pg)
 136                 return -ENOMEM;
 137         *pagep = pg;
 138
 139         D1(printk(KERN_DEBUG "jffs2_write_begin()\n"));
 140
 141         if (pageofs > inode->i_size) {
 142                 /* Make new hole frag from old EOF to new page */
 143                 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 144                 struct jffs2_raw_inode ri;
 145                 struct jffs2_full_dnode *fn;
 146                 uint32_t alloc_len;
 147
 148                 D1(printk(KERN_DEBUG "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
 149                           (unsigned int)inode->i_size, pageofs));
 150
 151                 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
 152                                           ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
 153                 if (ret)
 154                         goto out_page;
 155
 156                 mutex_lock(&f->sem);
 157                 memset(&ri, 0, sizeof(ri));
 158
 159                 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
 160                 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
 161                 ri.totlen = cpu_to_je32(sizeof(ri));
 162                 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
 163
 164                 ri.ino = cpu_to_je32(f->inocache->ino);
 165                 ri.version = cpu_to_je32(++f->highest_version);
 166                 ri.mode = cpu_to_jemode(inode->i_mode);
 167                 ri.uid = cpu_to_je16(inode->i_uid);
 168                 ri.gid = cpu_to_je16(inode->i_gid);
 169                 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
 170                 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());
 171                 ri.offset = cpu_to_je32(inode->i_size);
 172                 ri.dsize = cpu_to_je32(pageofs - inode->i_size);
 173                 ri.csize = cpu_to_je32(0);
 174                 ri.compr = JFFS2_COMPR_ZERO;
 175                 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
 176                 ri.data_crc = cpu_to_je32(0);
 177
 178                 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
 179
 180                 if (IS_ERR(fn)) {
 181                         ret = PTR_ERR(fn);
 182                         jffs2_complete_reservation(c);
 183                         mutex_unlock(&f->sem);
 184                         goto out_page;
 185                 }
 186                 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
 187                 if (f->metadata) {
 188                         jffs2_mark_node_obsolete(c, f->metadata->raw);
 189                         jffs2_free_full_dnode(f->metadata);
 190                         f->metadata = NULL;
 191                 }
 192                 if (ret) {
 193                         D1(printk(KERN_DEBUG "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", ret));
 194                         jffs2_mark_node_obsolete(c, fn->raw);
 195                         jffs2_free_full_dnode(fn);
 196                         jffs2_complete_reservation(c);
 197                         mutex_unlock(&f->sem);
 198                         goto out_page;
 199                 }
 200                 jffs2_complete_reservation(c);
 201                 inode->i_size = pageofs;
 202                 mutex_unlock(&f->sem);
 203         }
 204
 205         /*
 206          * Read in the page if it wasn't already present. Cannot optimize away
 207          * the whole page write case until jffs2_write_end can handle the
 208          * case of a short-copy.
 209          */
 210         if (!PageUptodate(pg)) {
 211                 mutex_lock(&f->sem);
 212                 ret = jffs2_do_readpage_nolock(inode, pg);
 213                 mutex_unlock(&f->sem);
 214                 if (ret)
 215                         goto out_page;
 216         }
 217         D1(printk(KERN_DEBUG "end write_begin(). pg->flags %lx\n", pg->flags));
 218         return ret;
 219
 220 out_page:
 221         unlock_page(pg);
 222         page_cache_release(pg);
 223         return ret;
 224 }
 225
 226 static int jffs2_write_end(struct file *filp, struct address_space *mapping,
 227                         loff_t pos, unsigned len, unsigned copied,
 228                         struct page *pg, void *fsdata)
 229 {
 230         /* Actually commit the write from the page cache page we're looking at.
 231          * For now, we write the full page out each time. It sucks, but it's simple
 232          */
 233         struct inode *inode = mapping->host;
 234         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 235         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 236         struct jffs2_raw_inode *ri;
 237         unsigned start = pos & (PAGE_CACHE_SIZE - 1);
 238         unsigned end = start + copied;
 239         unsigned aligned_start = start & ~3;
 240         int ret = 0;
 241         uint32_t writtenlen = 0;
 242
 243         D1(printk(KERN_DEBUG "jffs2_write_end(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
 244                   inode->i_ino, pg->index << PAGE_CACHE_SHIFT, start, end, pg->flags));
 245
 246         /* We need to avoid deadlock with page_cache_read() in
 247            jffs2_garbage_collect_pass(). So the page must be
 248            up to date to prevent page_cache_read() from trying
 249            to re-lock it. */
 250         BUG_ON(!PageUptodate(pg));
 251
 252         if (end == PAGE_CACHE_SIZE) {
 253                 /* When writing out the end of a page, write out the
 254                    _whole_ page. This helps to reduce the number of
 255                    nodes in files which have many short writes, like
 256                    syslog files. */
 257                 aligned_start = 0;
 258         }
 259
 260         ri = jffs2_alloc_raw_inode();
 261
 262         if (!ri) {
 263                 D1(printk(KERN_DEBUG "jffs2_write_end(): Allocation of raw inode failed\n"));
 264                 unlock_page(pg);
 265                 page_cache_release(pg);
 266                 return -ENOMEM;
 267         }
 268
 269         /* Set the fields that the generic jffs2_write_inode_range() code can't find */
 270         ri->ino = cpu_to_je32(inode->i_ino);
 271         ri->mode = cpu_to_jemode(inode->i_mode);
 272         ri->uid = cpu_to_je16(inode->i_uid);
 273         ri->gid = cpu_to_je16(inode->i_gid);
 274         ri->isize = cpu_to_je32((uint32_t)inode->i_size);
 275         ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds());
 276
 277         /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
 278            hurt to do it again. The alternative is ifdefs, which are ugly. */
 279         kmap(pg);
 280
 281         ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
 282                                       (pg->index << PAGE_CACHE_SHIFT) + aligned_start,
 283                                       end - aligned_start, &writtenlen);
 284
 285         kunmap(pg);
 286
 287         if (ret) {
 288                 /* There was an error writing. */
 289                 SetPageError(pg);
 290         }
 291
 292         /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
 293         writtenlen -= min(writtenlen, (start - aligned_start));
 294
 295         if (writtenlen) {
 296                 if (inode->i_size < pos + writtenlen) {
 297                         inode->i_size = pos + writtenlen;
 298                         inode->i_blocks = (inode->i_size + 511) >> 9;
 299
 300                         inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
 301                 }
 302         }
 303
 304         jffs2_free_raw_inode(ri);
 305
 306         if (start+writtenlen < end) {
 307                 /* generic_file_write has written more to the page cache than we've
 308                    actually written to the medium. Mark the page !Uptodate so that
 309                    it gets reread */
 310                 D1(printk(KERN_DEBUG "jffs2_write_end(): Not all bytes written. Marking page !uptodate\n"));
 311                 SetPageError(pg);
 312                 ClearPageUptodate(pg);
 313         }
 314
 315         D1(printk(KERN_DEBUG "jffs2_write_end() returning %d\n",
 316                                         writtenlen > 0 ? writtenlen : ret));
 317         unlock_page(pg);
 318         page_cache_release(pg);
 319         return writtenlen > 0 ? writtenlen : ret;
 320 }