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/slab.h>
  14 #include <linux/fs.h>
  15 #include <linux/time.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/highmem.h>
  18 #include <linux/crc32.h>
  19 #include <linux/jffs2.h>
  20 #include "nodelist.h"
  21
  22 static int jffs2_commit_write (struct file *filp, struct page *pg,
  23                                unsigned start, unsigned end);
  24 static int jffs2_prepare_write (struct file *filp, struct page *pg,
  25                                 unsigned start, unsigned end);
  26 static int jffs2_readpage (struct file *filp, struct page *pg);
  27
  28 int jffs2_fsync(struct file *filp, struct dentry *dentry, int datasync)
  29 {
  30         struct inode *inode = dentry->d_inode;
  31         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
  32
  33         /* Trigger GC to flush any pending writes for this inode */
  34         jffs2_flush_wbuf_gc(c, inode->i_ino);
  35
  36         return 0;
  37 }
  38
  39 const struct file_operations jffs2_file_operations =
  40 {
  41         .llseek =       generic_file_llseek,
  42         .open =         generic_file_open,
  43         .read =         do_sync_read,
  44         .aio_read =     generic_file_aio_read,
  45         .write =        do_sync_write,
  46         .aio_write =    generic_file_aio_write,
  47         .ioctl =        jffs2_ioctl,
  48         .mmap =         generic_file_readonly_mmap,
  49         .fsync =        jffs2_fsync,
  50         .splice_read =  generic_file_splice_read,
  51 };
  52
  53 /* jffs2_file_inode_operations */
  54
  55 const struct inode_operations jffs2_file_inode_operations =
  56 {
  57         .permission =   jffs2_permission,
  58         .setattr =      jffs2_setattr,
  59         .setxattr =     jffs2_setxattr,
  60         .getxattr =     jffs2_getxattr,
  61         .listxattr =    jffs2_listxattr,
  62         .removexattr =  jffs2_removexattr
  63 };
  64
  65 const struct address_space_operations jffs2_file_address_operations =
  66 {
  67         .readpage =     jffs2_readpage,
  68         .prepare_write =jffs2_prepare_write,
  69         .commit_write = jffs2_commit_write
  70 };
  71
  72 static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
  73 {
  74         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
  75         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
  76         unsigned char *pg_buf;
  77         int ret;
  78
  79         D2(printk(KERN_DEBUG "jffs2_do_readpage_nolock(): ino #%lu, page at offset 0x%lx\n", inode->i_ino, pg->index << PAGE_CACHE_SHIFT));
  80
  81         BUG_ON(!PageLocked(pg));
  82
  83         pg_buf = kmap(pg);
  84         /* FIXME: Can kmap fail? */
  85
  86         ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE);
  87
  88         if (ret) {
  89                 ClearPageUptodate(pg);
  90                 SetPageError(pg);
  91         } else {
  92                 SetPageUptodate(pg);
  93                 ClearPageError(pg);
  94         }
  95
  96         flush_dcache_page(pg);
  97         kunmap(pg);
  98
  99         D2(printk(KERN_DEBUG "readpage finished\n"));
 100         return 0;
 101 }
 102
 103 int jffs2_do_readpage_unlock(struct inode *inode, struct page *pg)
 104 {
 105         int ret = jffs2_do_readpage_nolock(inode, pg);
 106         unlock_page(pg);
 107         return ret;
 108 }
 109
 110
 111 static int jffs2_readpage (struct file *filp, struct page *pg)
 112 {
 113         struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
 114         int ret;
 115
 116         down(&f->sem);
 117         ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
 118         up(&f->sem);
 119         return ret;
 120 }
 121
 122 static int jffs2_prepare_write (struct file *filp, struct page *pg,
 123                                 unsigned start, unsigned end)
 124 {
 125         struct inode *inode = pg->mapping->host;
 126         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 127         uint32_t pageofs = pg->index << PAGE_CACHE_SHIFT;
 128         int ret = 0;
 129
 130         D1(printk(KERN_DEBUG "jffs2_prepare_write()\n"));
 131
 132         if (pageofs > inode->i_size) {
 133                 /* Make new hole frag from old EOF to new page */
 134                 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 135                 struct jffs2_raw_inode ri;
 136                 struct jffs2_full_dnode *fn;
 137                 uint32_t alloc_len;
 138
 139                 D1(printk(KERN_DEBUG "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
 140                           (unsigned int)inode->i_size, pageofs));
 141
 142                 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
 143                                           ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
 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, 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 (end == PAGE_CACHE_SIZE) {
 224                 if (!start) {
 225                         /* We need to avoid deadlock with page_cache_read() in
 226                            jffs2_garbage_collect_pass(). So we have to mark the
 227                            page up to date, to prevent page_cache_read() from
 228                            trying to re-lock it. */
 229                         SetPageUptodate(pg);
 230                 } else {
 231                         /* When writing out the end of a page, write out the
 232                            _whole_ page. This helps to reduce the number of
 233                            nodes in files which have many short writes, like
 234                            syslog files. */
 235                         start = aligned_start = 0;
 236                 }
 237         }
 238
 239         ri = jffs2_alloc_raw_inode();
 240
 241         if (!ri) {
 242                 D1(printk(KERN_DEBUG "jffs2_commit_write(): Allocation of raw inode failed\n"));
 243                 return -ENOMEM;
 244         }
 245
 246         /* Set the fields that the generic jffs2_write_inode_range() code can't find */
 247         ri->ino = cpu_to_je32(inode->i_ino);
 248         ri->mode = cpu_to_jemode(inode->i_mode);
 249         ri->uid = cpu_to_je16(inode->i_uid);
 250         ri->gid = cpu_to_je16(inode->i_gid);
 251         ri->isize = cpu_to_je32((uint32_t)inode->i_size);
 252         ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds());
 253
 254         /* In 2.4, it was already kmapped by generic_file_write(). Doesn't
 255            hurt to do it again. The alternative is ifdefs, which are ugly. */
 256         kmap(pg);
 257
 258         ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
 259                                       (pg->index << PAGE_CACHE_SHIFT) + aligned_start,
 260                                       end - aligned_start, &writtenlen);
 261
 262         kunmap(pg);
 263
 264         if (ret) {
 265                 /* There was an error writing. */
 266                 SetPageError(pg);
 267         }
 268
 269         /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
 270         if (writtenlen < (start&3))
 271                 writtenlen = 0;
 272         else
 273                 writtenlen -= (start&3);
 274
 275         if (writtenlen) {
 276                 if (inode->i_size < (pg->index << PAGE_CACHE_SHIFT) + start + writtenlen) {
 277                         inode->i_size = (pg->index << PAGE_CACHE_SHIFT) + start + writtenlen;
 278                         inode->i_blocks = (inode->i_size + 511) >> 9;
 279
 280                         inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
 281                 }
 282         }
 283
 284         jffs2_free_raw_inode(ri);
 285
 286         if (start+writtenlen < end) {
 287                 /* generic_file_write has written more to the page cache than we've
 288                    actually written to the medium. Mark the page !Uptodate so that
 289                    it gets reread */
 290                 D1(printk(KERN_DEBUG "jffs2_commit_write(): Not all bytes written. Marking page !uptodate\n"));
 291                 SetPageError(pg);
 292                 ClearPageUptodate(pg);
 293         }
 294
 295         D1(printk(KERN_DEBUG "jffs2_commit_write() returning %d\n",start+writtenlen==end?0:ret));
 296         return start+writtenlen==end?0:ret;
 297 }