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_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 = generic_file_splice_read, 60 }; 61 62 /* jffs2_file_inode_operations */ 63 64 const struct inode_operations jffs2_file_inode_operations = 65 { 66 .get_acl = jffs2_get_acl, 67 .set_acl = jffs2_set_acl, 68 .setattr = jffs2_setattr, 69 .setxattr = jffs2_setxattr, 70 .getxattr = jffs2_getxattr, 71 .listxattr = jffs2_listxattr, 72 .removexattr = jffs2_removexattr 73 }; 74 75 const struct address_space_operations jffs2_file_address_operations = 76 { 77 .readpage = jffs2_readpage, 78 .write_begin = jffs2_write_begin, 79 .write_end = jffs2_write_end, 80 }; 81 82 static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg) 83 { 84 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 85 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 86 unsigned char *pg_buf; 87 int ret; 88 89 jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n", 90 __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT); 91 92 BUG_ON(!PageLocked(pg)); 93 94 pg_buf = kmap(pg); 95 /* FIXME: Can kmap fail? */ 96 97 ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE); 98 99 if (ret) { 100 ClearPageUptodate(pg); 101 SetPageError(pg); 102 } else { 103 SetPageUptodate(pg); 104 ClearPageError(pg); 105 } 106 107 flush_dcache_page(pg); 108 kunmap(pg); 109 110 jffs2_dbg(2, "readpage finished\n"); 111 return ret; 112 } 113 114 int jffs2_do_readpage_unlock(struct inode *inode, struct page *pg) 115 { 116 int ret = jffs2_do_readpage_nolock(inode, pg); 117 unlock_page(pg); 118 return ret; 119 } 120 121 122 static int jffs2_readpage (struct file *filp, struct page *pg) 123 { 124 struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host); 125 int ret; 126 127 mutex_lock(&f->sem); 128 ret = jffs2_do_readpage_unlock(pg->mapping->host, pg); 129 mutex_unlock(&f->sem); 130 return ret; 131 } 132 133 static int jffs2_write_begin(struct file *filp, struct address_space *mapping, 134 loff_t pos, unsigned len, unsigned flags, 135 struct page **pagep, void **fsdata) 136 { 137 struct page *pg; 138 struct inode *inode = mapping->host; 139 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 140 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 141 struct jffs2_raw_inode ri; 142 uint32_t alloc_len = 0; 143 pgoff_t index = pos >> PAGE_CACHE_SHIFT; 144 uint32_t pageofs = index << PAGE_CACHE_SHIFT; 145 int ret = 0; 146 147 jffs2_dbg(1, "%s()\n", __func__); 148 149 if (pageofs > inode->i_size) { 150 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len, 151 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE); 152 if (ret) 153 return ret; 154 } 155 156 mutex_lock(&f->sem); 157 pg = grab_cache_page_write_begin(mapping, index, flags); 158 if (!pg) { 159 if (alloc_len) 160 jffs2_complete_reservation(c); 161 mutex_unlock(&f->sem); 162 return -ENOMEM; 163 } 164 *pagep = pg; 165 166 if (alloc_len) { 167 /* Make new hole frag from old EOF to new page */ 168 struct jffs2_full_dnode *fn; 169 170 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n", 171 (unsigned int)inode->i_size, pageofs); 172 173 memset(&ri, 0, sizeof(ri)); 174 175 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK); 176 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE); 177 ri.totlen = cpu_to_je32(sizeof(ri)); 178 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4)); 179 180 ri.ino = cpu_to_je32(f->inocache->ino); 181 ri.version = cpu_to_je32(++f->highest_version); 182 ri.mode = cpu_to_jemode(inode->i_mode); 183 ri.uid = cpu_to_je16(i_uid_read(inode)); 184 ri.gid = cpu_to_je16(i_gid_read(inode)); 185 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs)); 186 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds()); 187 ri.offset = cpu_to_je32(inode->i_size); 188 ri.dsize = cpu_to_je32(pageofs - inode->i_size); 189 ri.csize = cpu_to_je32(0); 190 ri.compr = JFFS2_COMPR_ZERO; 191 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8)); 192 ri.data_crc = cpu_to_je32(0); 193 194 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL); 195 196 if (IS_ERR(fn)) { 197 ret = PTR_ERR(fn); 198 jffs2_complete_reservation(c); 199 goto out_page; 200 } 201 ret = jffs2_add_full_dnode_to_inode(c, f, fn); 202 if (f->metadata) { 203 jffs2_mark_node_obsolete(c, f->metadata->raw); 204 jffs2_free_full_dnode(f->metadata); 205 f->metadata = NULL; 206 } 207 if (ret) { 208 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", 209 ret); 210 jffs2_mark_node_obsolete(c, fn->raw); 211 jffs2_free_full_dnode(fn); 212 jffs2_complete_reservation(c); 213 goto out_page; 214 } 215 jffs2_complete_reservation(c); 216 inode->i_size = pageofs; 217 } 218 219 /* 220 * Read in the page if it wasn't already present. Cannot optimize away 221 * the whole page write case until jffs2_write_end can handle the 222 * case of a short-copy. 223 */ 224 if (!PageUptodate(pg)) { 225 ret = jffs2_do_readpage_nolock(inode, pg); 226 if (ret) 227 goto out_page; 228 } 229 mutex_unlock(&f->sem); 230 jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags); 231 return ret; 232 233 out_page: 234 unlock_page(pg); 235 page_cache_release(pg); 236 mutex_unlock(&f->sem); 237 return ret; 238 } 239 240 static int jffs2_write_end(struct file *filp, struct address_space *mapping, 241 loff_t pos, unsigned len, unsigned copied, 242 struct page *pg, void *fsdata) 243 { 244 /* Actually commit the write from the page cache page we're looking at. 245 * For now, we write the full page out each time. It sucks, but it's simple 246 */ 247 struct inode *inode = mapping->host; 248 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 249 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 250 struct jffs2_raw_inode *ri; 251 unsigned start = pos & (PAGE_CACHE_SIZE - 1); 252 unsigned end = start + copied; 253 unsigned aligned_start = start & ~3; 254 int ret = 0; 255 uint32_t writtenlen = 0; 256 257 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n", 258 __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT, 259 start, end, pg->flags); 260 261 /* We need to avoid deadlock with page_cache_read() in 262 jffs2_garbage_collect_pass(). So the page must be 263 up to date to prevent page_cache_read() from trying 264 to re-lock it. */ 265 BUG_ON(!PageUptodate(pg)); 266 267 if (end == PAGE_CACHE_SIZE) { 268 /* When writing out the end of a page, write out the 269 _whole_ page. This helps to reduce the number of 270 nodes in files which have many short writes, like 271 syslog files. */ 272 aligned_start = 0; 273 } 274 275 ri = jffs2_alloc_raw_inode(); 276 277 if (!ri) { 278 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n", 279 __func__); 280 unlock_page(pg); 281 page_cache_release(pg); 282 return -ENOMEM; 283 } 284 285 /* Set the fields that the generic jffs2_write_inode_range() code can't find */ 286 ri->ino = cpu_to_je32(inode->i_ino); 287 ri->mode = cpu_to_jemode(inode->i_mode); 288 ri->uid = cpu_to_je16(i_uid_read(inode)); 289 ri->gid = cpu_to_je16(i_gid_read(inode)); 290 ri->isize = cpu_to_je32((uint32_t)inode->i_size); 291 ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds()); 292 293 /* In 2.4, it was already kmapped by generic_file_write(). Doesn't 294 hurt to do it again. The alternative is ifdefs, which are ugly. */ 295 kmap(pg); 296 297 ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start, 298 (pg->index << PAGE_CACHE_SHIFT) + aligned_start, 299 end - aligned_start, &writtenlen); 300 301 kunmap(pg); 302 303 if (ret) { 304 /* There was an error writing. */ 305 SetPageError(pg); 306 } 307 308 /* Adjust writtenlen for the padding we did, so we don't confuse our caller */ 309 writtenlen -= min(writtenlen, (start - aligned_start)); 310 311 if (writtenlen) { 312 if (inode->i_size < pos + writtenlen) { 313 inode->i_size = pos + writtenlen; 314 inode->i_blocks = (inode->i_size + 511) >> 9; 315 316 inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime)); 317 } 318 } 319 320 jffs2_free_raw_inode(ri); 321 322 if (start+writtenlen < end) { 323 /* generic_file_write has written more to the page cache than we've 324 actually written to the medium. Mark the page !Uptodate so that 325 it gets reread */ 326 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n", 327 __func__); 328 SetPageError(pg); 329 ClearPageUptodate(pg); 330 } 331 332 jffs2_dbg(1, "%s() returning %d\n", 333 __func__, writtenlen > 0 ? writtenlen : ret); 334 unlock_page(pg); 335 page_cache_release(pg); 336 return writtenlen > 0 ? writtenlen : ret; 337 } 338