fs/jffs2/file.c

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright © 2001-2007 Red Hat, Inc.
   5  * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
   6  *
   7  * Created by David Woodhouse <dwmw2@infradead.org>
   8  *
   9  * For licensing information, see the file 'LICENCE' in this directory.
  10  *
  11  */
  12
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/kernel.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_write_end(struct file *filp, struct address_space *mapping,
  25                         loff_t pos, unsigned len, unsigned copied,
  26                         struct folio *folio, void *fsdata);
  27 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
  28                         loff_t pos, unsigned len,
  29                         struct folio **foliop, void **fsdata);
  30 static int jffs2_read_folio(struct file *filp, struct folio *folio);
  31
  32 int jffs2_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
  33 {
  34         struct inode *inode = filp->f_mapping->host;
  35         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
  36         int ret;
  37
  38         ret = file_write_and_wait_range(filp, start, end);
  39         if (ret)
  40                 return ret;
  41
  42         inode_lock(inode);
  43         /* Trigger GC to flush any pending writes for this inode */
  44         jffs2_flush_wbuf_gc(c, inode->i_ino);
  45         inode_unlock(inode);
  46
  47         return 0;
  48 }
  49
  50 const struct file_operations jffs2_file_operations =
  51 {
  52         .llseek =       generic_file_llseek,
  53         .open =         generic_file_open,
  54         .read_iter =    generic_file_read_iter,
  55         .write_iter =   generic_file_write_iter,
  56         .unlocked_ioctl=jffs2_ioctl,
  57         .mmap =         generic_file_readonly_mmap,
  58         .fsync =        jffs2_fsync,
  59         .splice_read =  filemap_splice_read,
  60         .splice_write = iter_file_splice_write,
  61 };
  62
  63 /* jffs2_file_inode_operations */
  64
  65 const struct inode_operations jffs2_file_inode_operations =
  66 {
  67         .get_inode_acl =        jffs2_get_acl,
  68         .set_acl =      jffs2_set_acl,
  69         .setattr =      jffs2_setattr,
  70         .listxattr =    jffs2_listxattr,
  71 };
  72
  73 const struct address_space_operations jffs2_file_address_operations =
  74 {
  75         .read_folio =   jffs2_read_folio,
  76         .write_begin =  jffs2_write_begin,
  77         .write_end =    jffs2_write_end,
  78 };
  79
  80 static int jffs2_do_readpage_nolock(struct inode *inode, struct folio *folio)
  81 {
  82         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
  83         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
  84         unsigned char *kaddr;
  85         int ret;
  86
  87         jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n",
  88                   __func__, inode->i_ino, folio->index << PAGE_SHIFT);
  89
  90         BUG_ON(!folio_test_locked(folio));
  91
  92         kaddr = kmap_local_folio(folio, 0);
  93         ret = jffs2_read_inode_range(c, f, kaddr, folio->index << PAGE_SHIFT,
  94                                      PAGE_SIZE);
  95         kunmap_local(kaddr);
  96
  97         if (!ret)
  98                 folio_mark_uptodate(folio);
  99
 100         flush_dcache_folio(folio);
 101
 102         jffs2_dbg(2, "readpage finished\n");
 103         return ret;
 104 }
 105
 106 int __jffs2_read_folio(struct file *file, struct folio *folio)
 107 {
 108         int ret = jffs2_do_readpage_nolock(folio->mapping->host, folio);
 109         folio_unlock(folio);
 110         return ret;
 111 }
 112
 113 static int jffs2_read_folio(struct file *file, struct folio *folio)
 114 {
 115         struct jffs2_inode_info *f = JFFS2_INODE_INFO(folio->mapping->host);
 116         int ret;
 117
 118         mutex_lock(&f->sem);
 119         ret = __jffs2_read_folio(file, folio);
 120         mutex_unlock(&f->sem);
 121         return ret;
 122 }
 123
 124 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
 125                         loff_t pos, unsigned len,
 126                         struct folio **foliop, void **fsdata)
 127 {
 128         struct folio *folio;
 129         struct inode *inode = mapping->host;
 130         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 131         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 132         pgoff_t index = pos >> PAGE_SHIFT;
 133         int ret = 0;
 134
 135         jffs2_dbg(1, "%s()\n", __func__);
 136
 137         if (pos > inode->i_size) {
 138                 /* Make new hole frag from old EOF to new position */
 139                 struct jffs2_raw_inode ri;
 140                 struct jffs2_full_dnode *fn;
 141                 uint32_t alloc_len;
 142
 143                 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new position\n",
 144                           (unsigned int)inode->i_size, (uint32_t)pos);
 145
 146                 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
 147                                           ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
 148                 if (ret)
 149                         goto out_err;
 150
 151                 mutex_lock(&f->sem);
 152                 memset(&ri, 0, sizeof(ri));
 153
 154                 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
 155                 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
 156                 ri.totlen = cpu_to_je32(sizeof(ri));
 157                 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
 158
 159                 ri.ino = cpu_to_je32(f->inocache->ino);
 160                 ri.version = cpu_to_je32(++f->highest_version);
 161                 ri.mode = cpu_to_jemode(inode->i_mode);
 162                 ri.uid = cpu_to_je16(i_uid_read(inode));
 163                 ri.gid = cpu_to_je16(i_gid_read(inode));
 164                 ri.isize = cpu_to_je32((uint32_t)pos);
 165                 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW());
 166                 ri.offset = cpu_to_je32(inode->i_size);
 167                 ri.dsize = cpu_to_je32((uint32_t)pos - inode->i_size);
 168                 ri.csize = cpu_to_je32(0);
 169                 ri.compr = JFFS2_COMPR_ZERO;
 170                 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
 171                 ri.data_crc = cpu_to_je32(0);
 172
 173                 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
 174
 175                 if (IS_ERR(fn)) {
 176                         ret = PTR_ERR(fn);
 177                         jffs2_complete_reservation(c);
 178                         mutex_unlock(&f->sem);
 179                         goto out_err;
 180                 }
 181                 ret = jffs2_add_full_dnode_to_inode(c, f, fn);
 182                 if (f->metadata) {
 183                         jffs2_mark_node_obsolete(c, f->metadata->raw);
 184                         jffs2_free_full_dnode(f->metadata);
 185                         f->metadata = NULL;
 186                 }
 187                 if (ret) {
 188                         jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
 189                                   ret);
 190                         jffs2_mark_node_obsolete(c, fn->raw);
 191                         jffs2_free_full_dnode(fn);
 192                         jffs2_complete_reservation(c);
 193                         mutex_unlock(&f->sem);
 194                         goto out_err;
 195                 }
 196                 jffs2_complete_reservation(c);
 197                 inode->i_size = pos;
 198                 mutex_unlock(&f->sem);
 199         }
 200
 201         /*
 202          * While getting a page and reading data in, lock c->alloc_sem until
 203          * the page is Uptodate. Otherwise GC task may attempt to read the same
 204          * page in read_cache_page(), which causes a deadlock.
 205          */
 206         mutex_lock(&c->alloc_sem);
 207         folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
 208                         mapping_gfp_mask(mapping));
 209         if (IS_ERR(folio)) {
 210                 ret = PTR_ERR(folio);
 211                 goto release_sem;
 212         }
 213         *foliop = folio;
 214
 215         /*
 216          * Read in the folio if it wasn't already present. Cannot optimize away
 217          * the whole folio write case until jffs2_write_end can handle the
 218          * case of a short-copy.
 219          */
 220         if (!folio_test_uptodate(folio)) {
 221                 mutex_lock(&f->sem);
 222                 ret = jffs2_do_readpage_nolock(inode, folio);
 223                 mutex_unlock(&f->sem);
 224                 if (ret) {
 225                         folio_unlock(folio);
 226                         folio_put(folio);
 227                         goto release_sem;
 228                 }
 229         }
 230         jffs2_dbg(1, "end write_begin(). folio->flags %lx\n", folio->flags);
 231
 232 release_sem:
 233         mutex_unlock(&c->alloc_sem);
 234 out_err:
 235         return ret;
 236 }
 237
 238 static int jffs2_write_end(struct file *filp, struct address_space *mapping,
 239                         loff_t pos, unsigned len, unsigned copied,
 240                         struct folio *folio, void *fsdata)
 241 {
 242         /* Actually commit the write from the page cache page we're looking at.
 243          * For now, we write the full page out each time. It sucks, but it's simple
 244          */
 245         struct inode *inode = mapping->host;
 246         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 247         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 248         struct jffs2_raw_inode *ri;
 249         unsigned start = pos & (PAGE_SIZE - 1);
 250         unsigned end = start + copied;
 251         unsigned aligned_start = start & ~3;
 252         int ret = 0;
 253         uint32_t writtenlen = 0;
 254         void *buf;
 255
 256         jffs2_dbg(1, "%s(): ino #%lu, page at 0x%llx, range %d-%d, flags %lx\n",
 257                   __func__, inode->i_ino, folio_pos(folio),
 258                   start, end, folio->flags);
 259
 260         /* We need to avoid deadlock with page_cache_read() in
 261            jffs2_garbage_collect_pass(). So the folio must be
 262            up to date to prevent page_cache_read() from trying
 263            to re-lock it. */
 264         BUG_ON(!folio_test_uptodate(folio));
 265
 266         if (end == PAGE_SIZE) {
 267                 /* When writing out the end of a page, write out the
 268                    _whole_ page. This helps to reduce the number of
 269                    nodes in files which have many short writes, like
 270                    syslog files. */
 271                 aligned_start = 0;
 272         }
 273
 274         ri = jffs2_alloc_raw_inode();
 275
 276         if (!ri) {
 277                 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
 278                           __func__);
 279                 folio_unlock(folio);
 280                 folio_put(folio);
 281                 return -ENOMEM;
 282         }
 283
 284         /* Set the fields that the generic jffs2_write_inode_range() code can't find */
 285         ri->ino = cpu_to_je32(inode->i_ino);
 286         ri->mode = cpu_to_jemode(inode->i_mode);
 287         ri->uid = cpu_to_je16(i_uid_read(inode));
 288         ri->gid = cpu_to_je16(i_gid_read(inode));
 289         ri->isize = cpu_to_je32((uint32_t)inode->i_size);
 290         ri->atime = ri->ctime = ri->mtime = cpu_to_je32(JFFS2_NOW());
 291
 292         buf = kmap_local_folio(folio, aligned_start);
 293         ret = jffs2_write_inode_range(c, f, ri, buf,
 294                                       folio_pos(folio) + aligned_start,
 295                                       end - aligned_start, &writtenlen);
 296         kunmap_local(buf);
 297
 298         if (ret)
 299                 mapping_set_error(mapping, ret);
 300
 301         /* Adjust writtenlen for the padding we did, so we don't confuse our caller */
 302         writtenlen -= min(writtenlen, (start - aligned_start));
 303
 304         if (writtenlen) {
 305                 if (inode->i_size < pos + writtenlen) {
 306                         inode->i_size = pos + writtenlen;
 307                         inode->i_blocks = (inode->i_size + 511) >> 9;
 308
 309                         inode_set_mtime_to_ts(inode,
 310                                               inode_set_ctime_to_ts(inode, ITIME(je32_to_cpu(ri->ctime))));
 311                 }
 312         }
 313
 314         jffs2_free_raw_inode(ri);
 315
 316         if (start+writtenlen < end) {
 317                 /* generic_file_write has written more to the page cache than we've
 318                    actually written to the medium. Mark the page !Uptodate so that
 319                    it gets reread */
 320                 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n",
 321                         __func__);
 322                 folio_clear_uptodate(folio);
 323         }
 324
 325         jffs2_dbg(1, "%s() returning %d\n",
 326                   __func__, writtenlen > 0 ? writtenlen : ret);
 327         folio_unlock(folio);
 328         folio_put(folio);
 329         return writtenlen > 0 ? writtenlen : ret;
 330 }