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 page *pg, void *fsdata); 27 static int jffs2_write_begin(struct file *filp, struct address_space *mapping, 28 loff_t pos, unsigned len, unsigned flags, 29 struct page **pagep, void **fsdata); 30 static int jffs2_readpage (struct file *filp, struct page *pg); 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 = filemap_write_and_wait_range(inode->i_mapping, start, end); 39 if (ret) 40 return ret; 41 42 mutex_lock(&inode->i_mutex); 43 /* Trigger GC to flush any pending writes for this inode */ 44 jffs2_flush_wbuf_gc(c, inode->i_ino); 45 mutex_unlock(&inode->i_mutex); 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 = do_sync_read, 55 .aio_read = generic_file_aio_read, 56 .write = do_sync_write, 57 .aio_write = generic_file_aio_write, 58 .unlocked_ioctl=jffs2_ioctl, 59 .mmap = generic_file_readonly_mmap, 60 .fsync = jffs2_fsync, 61 .splice_read = generic_file_splice_read, 62 }; 63 64 /* jffs2_file_inode_operations */ 65 66 const struct inode_operations jffs2_file_inode_operations = 67 { 68 .get_acl = jffs2_get_acl, 69 .setattr = jffs2_setattr, 70 .setxattr = jffs2_setxattr, 71 .getxattr = jffs2_getxattr, 72 .listxattr = jffs2_listxattr, 73 .removexattr = jffs2_removexattr 74 }; 75 76 const struct address_space_operations jffs2_file_address_operations = 77 { 78 .readpage = jffs2_readpage, 79 .write_begin = jffs2_write_begin, 80 .write_end = jffs2_write_end, 81 }; 82 83 static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg) 84 { 85 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 86 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 87 unsigned char *pg_buf; 88 int ret; 89 90 jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n", 91 __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT); 92 93 BUG_ON(!PageLocked(pg)); 94 95 pg_buf = kmap(pg); 96 /* FIXME: Can kmap fail? */ 97 98 ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE); 99 100 if (ret) { 101 ClearPageUptodate(pg); 102 SetPageError(pg); 103 } else { 104 SetPageUptodate(pg); 105 ClearPageError(pg); 106 } 107 108 flush_dcache_page(pg); 109 kunmap(pg); 110 111 jffs2_dbg(2, "readpage finished\n"); 112 return ret; 113 } 114 115 int jffs2_do_readpage_unlock(struct inode *inode, struct page *pg) 116 { 117 int ret = jffs2_do_readpage_nolock(inode, pg); 118 unlock_page(pg); 119 return ret; 120 } 121 122 123 static int jffs2_readpage (struct file *filp, struct page *pg) 124 { 125 struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host); 126 int ret; 127 128 mutex_lock(&f->sem); 129 ret = jffs2_do_readpage_unlock(pg->mapping->host, pg); 130 mutex_unlock(&f->sem); 131 return ret; 132 } 133 134 static int jffs2_write_begin(struct file *filp, struct address_space *mapping, 135 loff_t pos, unsigned len, unsigned flags, 136 struct page **pagep, void **fsdata) 137 { 138 struct page *pg; 139 struct inode *inode = mapping->host; 140 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 141 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 142 struct jffs2_raw_inode ri; 143 uint32_t alloc_len = 0; 144 pgoff_t index = pos >> PAGE_CACHE_SHIFT; 145 uint32_t pageofs = index << PAGE_CACHE_SHIFT; 146 int ret = 0; 147 148 jffs2_dbg(1, "%s()\n", __func__); 149 150 if (pageofs > inode->i_size) { 151 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len, 152 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE); 153 if (ret) 154 return ret; 155 } 156 157 mutex_lock(&f->sem); 158 pg = grab_cache_page_write_begin(mapping, index, flags); 159 if (!pg) { 160 if (alloc_len) 161 jffs2_complete_reservation(c); 162 mutex_unlock(&f->sem); 163 return -ENOMEM; 164 } 165 *pagep = pg; 166 167 if (alloc_len) { 168 /* Make new hole frag from old EOF to new page */ 169 struct jffs2_full_dnode *fn; 170 171 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n", 172 (unsigned int)inode->i_size, pageofs); 173 174 memset(&ri, 0, sizeof(ri)); 175 176 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK); 177 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE); 178 ri.totlen = cpu_to_je32(sizeof(ri)); 179 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4)); 180 181 ri.ino = cpu_to_je32(f->inocache->ino); 182 ri.version = cpu_to_je32(++f->highest_version); 183 ri.mode = cpu_to_jemode(inode->i_mode); 184 ri.uid = cpu_to_je16(i_uid_read(inode)); 185 ri.gid = cpu_to_je16(i_gid_read(inode)); 186 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs)); 187 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds()); 188 ri.offset = cpu_to_je32(inode->i_size); 189 ri.dsize = cpu_to_je32(pageofs - inode->i_size); 190 ri.csize = cpu_to_je32(0); 191 ri.compr = JFFS2_COMPR_ZERO; 192 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8)); 193 ri.data_crc = cpu_to_je32(0); 194 195 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL); 196 197 if (IS_ERR(fn)) { 198 ret = PTR_ERR(fn); 199 jffs2_complete_reservation(c); 200 goto out_page; 201 } 202 ret = jffs2_add_full_dnode_to_inode(c, f, fn); 203 if (f->metadata) { 204 jffs2_mark_node_obsolete(c, f->metadata->raw); 205 jffs2_free_full_dnode(f->metadata); 206 f->metadata = NULL; 207 } 208 if (ret) { 209 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", 210 ret); 211 jffs2_mark_node_obsolete(c, fn->raw); 212 jffs2_free_full_dnode(fn); 213 jffs2_complete_reservation(c); 214 goto out_page; 215 } 216 jffs2_complete_reservation(c); 217 inode->i_size = pageofs; 218 } 219 220 /* 221 * Read in the page if it wasn't already present. Cannot optimize away 222 * the whole page write case until jffs2_write_end can handle the 223 * case of a short-copy. 224 */ 225 if (!PageUptodate(pg)) { 226 ret = jffs2_do_readpage_nolock(inode, pg); 227 if (ret) 228 goto out_page; 229 } 230 mutex_unlock(&f->sem); 231 jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags); 232 return ret; 233 234 out_page: 235 unlock_page(pg); 236 page_cache_release(pg); 237 mutex_unlock(&f->sem); 238 return ret; 239 } 240 241 static int jffs2_write_end(struct file *filp, struct address_space *mapping, 242 loff_t pos, unsigned len, unsigned copied, 243 struct page *pg, void *fsdata) 244 { 245 /* Actually commit the write from the page cache page we're looking at. 246 * For now, we write the full page out each time. It sucks, but it's simple 247 */ 248 struct inode *inode = mapping->host; 249 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 250 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 251 struct jffs2_raw_inode *ri; 252 unsigned start = pos & (PAGE_CACHE_SIZE - 1); 253 unsigned end = start + copied; 254 unsigned aligned_start = start & ~3; 255 int ret = 0; 256 uint32_t writtenlen = 0; 257 258 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n", 259 __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT, 260 start, end, pg->flags); 261 262 /* We need to avoid deadlock with page_cache_read() in 263 jffs2_garbage_collect_pass(). So the page must be 264 up to date to prevent page_cache_read() from trying 265 to re-lock it. */ 266 BUG_ON(!PageUptodate(pg)); 267 268 if (end == PAGE_CACHE_SIZE) { 269 /* When writing out the end of a page, write out the 270 _whole_ page. This helps to reduce the number of 271 nodes in files which have many short writes, like 272 syslog files. */ 273 aligned_start = 0; 274 } 275 276 ri = jffs2_alloc_raw_inode(); 277 278 if (!ri) { 279 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n", 280 __func__); 281 unlock_page(pg); 282 page_cache_release(pg); 283 return -ENOMEM; 284 } 285 286 /* Set the fields that the generic jffs2_write_inode_range() code can't find */ 287 ri->ino = cpu_to_je32(inode->i_ino); 288 ri->mode = cpu_to_jemode(inode->i_mode); 289 ri->uid = cpu_to_je16(i_uid_read(inode)); 290 ri->gid = cpu_to_je16(i_gid_read(inode)); 291 ri->isize = cpu_to_je32((uint32_t)inode->i_size); 292 ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds()); 293 294 /* In 2.4, it was already kmapped by generic_file_write(). Doesn't 295 hurt to do it again. The alternative is ifdefs, which are ugly. */ 296 kmap(pg); 297 298 ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start, 299 (pg->index << PAGE_CACHE_SHIFT) + aligned_start, 300 end - aligned_start, &writtenlen); 301 302 kunmap(pg); 303 304 if (ret) { 305 /* There was an error writing. */ 306 SetPageError(pg); 307 } 308 309 /* Adjust writtenlen for the padding we did, so we don't confuse our caller */ 310 writtenlen -= min(writtenlen, (start - aligned_start)); 311 312 if (writtenlen) { 313 if (inode->i_size < pos + writtenlen) { 314 inode->i_size = pos + writtenlen; 315 inode->i_blocks = (inode->i_size + 511) >> 9; 316 317 inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime)); 318 } 319 } 320 321 jffs2_free_raw_inode(ri); 322 323 if (start+writtenlen < end) { 324 /* generic_file_write has written more to the page cache than we've 325 actually written to the medium. Mark the page !Uptodate so that 326 it gets reread */ 327 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n", 328 __func__); 329 SetPageError(pg); 330 ClearPageUptodate(pg); 331 } 332 333 jffs2_dbg(1, "%s() returning %d\n", 334 __func__, writtenlen > 0 ? writtenlen : ret); 335 unlock_page(pg); 336 page_cache_release(pg); 337 return writtenlen > 0 ? writtenlen : ret; 338 } 339