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 = new_sync_read, 55 .read_iter = generic_file_read_iter, 56 .write = new_sync_write, 57 .write_iter = generic_file_write_iter, 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 .set_acl = jffs2_set_acl, 70 .setattr = jffs2_setattr, 71 .setxattr = jffs2_setxattr, 72 .getxattr = jffs2_getxattr, 73 .listxattr = jffs2_listxattr, 74 .removexattr = jffs2_removexattr 75 }; 76 77 const struct address_space_operations jffs2_file_address_operations = 78 { 79 .readpage = jffs2_readpage, 80 .write_begin = jffs2_write_begin, 81 .write_end = jffs2_write_end, 82 }; 83 84 static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg) 85 { 86 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 87 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 88 unsigned char *pg_buf; 89 int ret; 90 91 jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n", 92 __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT); 93 94 BUG_ON(!PageLocked(pg)); 95 96 pg_buf = kmap(pg); 97 /* FIXME: Can kmap fail? */ 98 99 ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE); 100 101 if (ret) { 102 ClearPageUptodate(pg); 103 SetPageError(pg); 104 } else { 105 SetPageUptodate(pg); 106 ClearPageError(pg); 107 } 108 109 flush_dcache_page(pg); 110 kunmap(pg); 111 112 jffs2_dbg(2, "readpage finished\n"); 113 return ret; 114 } 115 116 int jffs2_do_readpage_unlock(struct inode *inode, struct page *pg) 117 { 118 int ret = jffs2_do_readpage_nolock(inode, pg); 119 unlock_page(pg); 120 return ret; 121 } 122 123 124 static int jffs2_readpage (struct file *filp, struct page *pg) 125 { 126 struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host); 127 int ret; 128 129 mutex_lock(&f->sem); 130 ret = jffs2_do_readpage_unlock(pg->mapping->host, pg); 131 mutex_unlock(&f->sem); 132 return ret; 133 } 134 135 static int jffs2_write_begin(struct file *filp, struct address_space *mapping, 136 loff_t pos, unsigned len, unsigned flags, 137 struct page **pagep, void **fsdata) 138 { 139 struct page *pg; 140 struct inode *inode = mapping->host; 141 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 142 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 143 struct jffs2_raw_inode ri; 144 uint32_t alloc_len = 0; 145 pgoff_t index = pos >> PAGE_CACHE_SHIFT; 146 uint32_t pageofs = index << PAGE_CACHE_SHIFT; 147 int ret = 0; 148 149 jffs2_dbg(1, "%s()\n", __func__); 150 151 if (pageofs > inode->i_size) { 152 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len, 153 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE); 154 if (ret) 155 return ret; 156 } 157 158 mutex_lock(&f->sem); 159 pg = grab_cache_page_write_begin(mapping, index, flags); 160 if (!pg) { 161 if (alloc_len) 162 jffs2_complete_reservation(c); 163 mutex_unlock(&f->sem); 164 return -ENOMEM; 165 } 166 *pagep = pg; 167 168 if (alloc_len) { 169 /* Make new hole frag from old EOF to new page */ 170 struct jffs2_full_dnode *fn; 171 172 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n", 173 (unsigned int)inode->i_size, pageofs); 174 175 memset(&ri, 0, sizeof(ri)); 176 177 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK); 178 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE); 179 ri.totlen = cpu_to_je32(sizeof(ri)); 180 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4)); 181 182 ri.ino = cpu_to_je32(f->inocache->ino); 183 ri.version = cpu_to_je32(++f->highest_version); 184 ri.mode = cpu_to_jemode(inode->i_mode); 185 ri.uid = cpu_to_je16(i_uid_read(inode)); 186 ri.gid = cpu_to_je16(i_gid_read(inode)); 187 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs)); 188 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds()); 189 ri.offset = cpu_to_je32(inode->i_size); 190 ri.dsize = cpu_to_je32(pageofs - inode->i_size); 191 ri.csize = cpu_to_je32(0); 192 ri.compr = JFFS2_COMPR_ZERO; 193 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8)); 194 ri.data_crc = cpu_to_je32(0); 195 196 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL); 197 198 if (IS_ERR(fn)) { 199 ret = PTR_ERR(fn); 200 jffs2_complete_reservation(c); 201 goto out_page; 202 } 203 ret = jffs2_add_full_dnode_to_inode(c, f, fn); 204 if (f->metadata) { 205 jffs2_mark_node_obsolete(c, f->metadata->raw); 206 jffs2_free_full_dnode(f->metadata); 207 f->metadata = NULL; 208 } 209 if (ret) { 210 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", 211 ret); 212 jffs2_mark_node_obsolete(c, fn->raw); 213 jffs2_free_full_dnode(fn); 214 jffs2_complete_reservation(c); 215 goto out_page; 216 } 217 jffs2_complete_reservation(c); 218 inode->i_size = pageofs; 219 } 220 221 /* 222 * Read in the page if it wasn't already present. Cannot optimize away 223 * the whole page write case until jffs2_write_end can handle the 224 * case of a short-copy. 225 */ 226 if (!PageUptodate(pg)) { 227 ret = jffs2_do_readpage_nolock(inode, pg); 228 if (ret) 229 goto out_page; 230 } 231 mutex_unlock(&f->sem); 232 jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags); 233 return ret; 234 235 out_page: 236 unlock_page(pg); 237 page_cache_release(pg); 238 mutex_unlock(&f->sem); 239 return ret; 240 } 241 242 static int jffs2_write_end(struct file *filp, struct address_space *mapping, 243 loff_t pos, unsigned len, unsigned copied, 244 struct page *pg, void *fsdata) 245 { 246 /* Actually commit the write from the page cache page we're looking at. 247 * For now, we write the full page out each time. It sucks, but it's simple 248 */ 249 struct inode *inode = mapping->host; 250 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 251 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 252 struct jffs2_raw_inode *ri; 253 unsigned start = pos & (PAGE_CACHE_SIZE - 1); 254 unsigned end = start + copied; 255 unsigned aligned_start = start & ~3; 256 int ret = 0; 257 uint32_t writtenlen = 0; 258 259 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n", 260 __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT, 261 start, end, pg->flags); 262 263 /* We need to avoid deadlock with page_cache_read() in 264 jffs2_garbage_collect_pass(). So the page must be 265 up to date to prevent page_cache_read() from trying 266 to re-lock it. */ 267 BUG_ON(!PageUptodate(pg)); 268 269 if (end == PAGE_CACHE_SIZE) { 270 /* When writing out the end of a page, write out the 271 _whole_ page. This helps to reduce the number of 272 nodes in files which have many short writes, like 273 syslog files. */ 274 aligned_start = 0; 275 } 276 277 ri = jffs2_alloc_raw_inode(); 278 279 if (!ri) { 280 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n", 281 __func__); 282 unlock_page(pg); 283 page_cache_release(pg); 284 return -ENOMEM; 285 } 286 287 /* Set the fields that the generic jffs2_write_inode_range() code can't find */ 288 ri->ino = cpu_to_je32(inode->i_ino); 289 ri->mode = cpu_to_jemode(inode->i_mode); 290 ri->uid = cpu_to_je16(i_uid_read(inode)); 291 ri->gid = cpu_to_je16(i_gid_read(inode)); 292 ri->isize = cpu_to_je32((uint32_t)inode->i_size); 293 ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds()); 294 295 /* In 2.4, it was already kmapped by generic_file_write(). Doesn't 296 hurt to do it again. The alternative is ifdefs, which are ugly. */ 297 kmap(pg); 298 299 ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start, 300 (pg->index << PAGE_CACHE_SHIFT) + aligned_start, 301 end - aligned_start, &writtenlen); 302 303 kunmap(pg); 304 305 if (ret) { 306 /* There was an error writing. */ 307 SetPageError(pg); 308 } 309 310 /* Adjust writtenlen for the padding we did, so we don't confuse our caller */ 311 writtenlen -= min(writtenlen, (start - aligned_start)); 312 313 if (writtenlen) { 314 if (inode->i_size < pos + writtenlen) { 315 inode->i_size = pos + writtenlen; 316 inode->i_blocks = (inode->i_size + 511) >> 9; 317 318 inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime)); 319 } 320 } 321 322 jffs2_free_raw_inode(ri); 323 324 if (start+writtenlen < end) { 325 /* generic_file_write has written more to the page cache than we've 326 actually written to the medium. Mark the page !Uptodate so that 327 it gets reread */ 328 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n", 329 __func__); 330 SetPageError(pg); 331 ClearPageUptodate(pg); 332 } 333 334 jffs2_dbg(1, "%s() returning %d\n", 335 __func__, writtenlen > 0 ? writtenlen : ret); 336 unlock_page(pg); 337 page_cache_release(pg); 338 return writtenlen > 0 ? writtenlen : ret; 339 } 340