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 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 = 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_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_SHIFT, 98 PAGE_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 pgoff_t index = pos >> PAGE_SHIFT; 142 uint32_t pageofs = index << PAGE_SHIFT; 143 int ret = 0; 144 145 pg = grab_cache_page_write_begin(mapping, index, flags); 146 if (!pg) 147 return -ENOMEM; 148 *pagep = pg; 149 150 jffs2_dbg(1, "%s()\n", __func__); 151 152 if (pageofs > inode->i_size) { 153 /* Make new hole frag from old EOF to new page */ 154 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 155 struct jffs2_raw_inode ri; 156 struct jffs2_full_dnode *fn; 157 uint32_t alloc_len; 158 159 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n", 160 (unsigned int)inode->i_size, pageofs); 161 162 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len, 163 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE); 164 if (ret) 165 goto out_page; 166 167 mutex_lock(&f->sem); 168 memset(&ri, 0, sizeof(ri)); 169 170 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK); 171 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE); 172 ri.totlen = cpu_to_je32(sizeof(ri)); 173 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4)); 174 175 ri.ino = cpu_to_je32(f->inocache->ino); 176 ri.version = cpu_to_je32(++f->highest_version); 177 ri.mode = cpu_to_jemode(inode->i_mode); 178 ri.uid = cpu_to_je16(i_uid_read(inode)); 179 ri.gid = cpu_to_je16(i_gid_read(inode)); 180 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs)); 181 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds()); 182 ri.offset = cpu_to_je32(inode->i_size); 183 ri.dsize = cpu_to_je32(pageofs - inode->i_size); 184 ri.csize = cpu_to_je32(0); 185 ri.compr = JFFS2_COMPR_ZERO; 186 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8)); 187 ri.data_crc = cpu_to_je32(0); 188 189 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL); 190 191 if (IS_ERR(fn)) { 192 ret = PTR_ERR(fn); 193 jffs2_complete_reservation(c); 194 mutex_unlock(&f->sem); 195 goto out_page; 196 } 197 ret = jffs2_add_full_dnode_to_inode(c, f, fn); 198 if (f->metadata) { 199 jffs2_mark_node_obsolete(c, f->metadata->raw); 200 jffs2_free_full_dnode(f->metadata); 201 f->metadata = NULL; 202 } 203 if (ret) { 204 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", 205 ret); 206 jffs2_mark_node_obsolete(c, fn->raw); 207 jffs2_free_full_dnode(fn); 208 jffs2_complete_reservation(c); 209 mutex_unlock(&f->sem); 210 goto out_page; 211 } 212 jffs2_complete_reservation(c); 213 inode->i_size = pageofs; 214 mutex_unlock(&f->sem); 215 } 216 217 /* 218 * Read in the page if it wasn't already present. Cannot optimize away 219 * the whole page write case until jffs2_write_end can handle the 220 * case of a short-copy. 221 */ 222 if (!PageUptodate(pg)) { 223 mutex_lock(&f->sem); 224 ret = jffs2_do_readpage_nolock(inode, pg); 225 mutex_unlock(&f->sem); 226 if (ret) 227 goto out_page; 228 } 229 jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags); 230 return ret; 231 232 out_page: 233 unlock_page(pg); 234 put_page(pg); 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 page *pg, 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; 254 255 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n", 256 __func__, inode->i_ino, pg->index << PAGE_SHIFT, 257 start, end, pg->flags); 258 259 /* We need to avoid deadlock with page_cache_read() in 260 jffs2_garbage_collect_pass(). So the page must be 261 up to date to prevent page_cache_read() from trying 262 to re-lock it. */ 263 BUG_ON(!PageUptodate(pg)); 264 265 if (end == PAGE_SIZE) { 266 /* When writing out the end of a page, write out the 267 _whole_ page. This helps to reduce the number of 268 nodes in files which have many short writes, like 269 syslog files. */ 270 aligned_start = 0; 271 } 272 273 ri = jffs2_alloc_raw_inode(); 274 275 if (!ri) { 276 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n", 277 __func__); 278 unlock_page(pg); 279 put_page(pg); 280 return -ENOMEM; 281 } 282 283 /* Set the fields that the generic jffs2_write_inode_range() code can't find */ 284 ri->ino = cpu_to_je32(inode->i_ino); 285 ri->mode = cpu_to_jemode(inode->i_mode); 286 ri->uid = cpu_to_je16(i_uid_read(inode)); 287 ri->gid = cpu_to_je16(i_gid_read(inode)); 288 ri->isize = cpu_to_je32((uint32_t)inode->i_size); 289 ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds()); 290 291 /* In 2.4, it was already kmapped by generic_file_write(). Doesn't 292 hurt to do it again. The alternative is ifdefs, which are ugly. */ 293 kmap(pg); 294 295 ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start, 296 (pg->index << PAGE_SHIFT) + aligned_start, 297 end - aligned_start, &writtenlen); 298 299 kunmap(pg); 300 301 if (ret) { 302 /* There was an error writing. */ 303 SetPageError(pg); 304 } 305 306 /* Adjust writtenlen for the padding we did, so we don't confuse our caller */ 307 writtenlen -= min(writtenlen, (start - aligned_start)); 308 309 if (writtenlen) { 310 if (inode->i_size < pos + writtenlen) { 311 inode->i_size = pos + writtenlen; 312 inode->i_blocks = (inode->i_size + 511) >> 9; 313 314 inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime)); 315 } 316 } 317 318 jffs2_free_raw_inode(ri); 319 320 if (start+writtenlen < end) { 321 /* generic_file_write has written more to the page cache than we've 322 actually written to the medium. Mark the page !Uptodate so that 323 it gets reread */ 324 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n", 325 __func__); 326 SetPageError(pg); 327 ClearPageUptodate(pg); 328 } 329 330 jffs2_dbg(1, "%s() returning %d\n", 331 __func__, writtenlen > 0 ? writtenlen : ret); 332 unlock_page(pg); 333 put_page(pg); 334 return writtenlen > 0 ? writtenlen : ret; 335 } 336