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 = 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 = generic_file_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_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 .readpage = jffs2_readpage, 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 page *pg) 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 *pg_buf; 85 int ret; 86 87 jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n", 88 __func__, inode->i_ino, pg->index << PAGE_SHIFT); 89 90 BUG_ON(!PageLocked(pg)); 91 92 pg_buf = kmap(pg); 93 /* FIXME: Can kmap fail? */ 94 95 ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_SHIFT, 96 PAGE_SIZE); 97 98 if (ret) { 99 ClearPageUptodate(pg); 100 SetPageError(pg); 101 } else { 102 SetPageUptodate(pg); 103 ClearPageError(pg); 104 } 105 106 flush_dcache_page(pg); 107 kunmap(pg); 108 109 jffs2_dbg(2, "readpage finished\n"); 110 return ret; 111 } 112 113 int jffs2_do_readpage_unlock(void *data, struct page *pg) 114 { 115 int ret = jffs2_do_readpage_nolock(data, pg); 116 unlock_page(pg); 117 return ret; 118 } 119 120 121 static int jffs2_readpage (struct file *filp, struct page *pg) 122 { 123 struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host); 124 int ret; 125 126 mutex_lock(&f->sem); 127 ret = jffs2_do_readpage_unlock(pg->mapping->host, pg); 128 mutex_unlock(&f->sem); 129 return ret; 130 } 131 132 static int jffs2_write_begin(struct file *filp, struct address_space *mapping, 133 loff_t pos, unsigned len, unsigned flags, 134 struct page **pagep, void **fsdata) 135 { 136 struct page *pg; 137 struct inode *inode = mapping->host; 138 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 139 pgoff_t index = pos >> PAGE_SHIFT; 140 uint32_t pageofs = index << PAGE_SHIFT; 141 int ret = 0; 142 143 pg = grab_cache_page_write_begin(mapping, index, flags); 144 if (!pg) 145 return -ENOMEM; 146 *pagep = pg; 147 148 jffs2_dbg(1, "%s()\n", __func__); 149 150 if (pageofs > inode->i_size) { 151 /* Make new hole frag from old EOF to new page */ 152 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 153 struct jffs2_raw_inode ri; 154 struct jffs2_full_dnode *fn; 155 uint32_t alloc_len; 156 157 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n", 158 (unsigned int)inode->i_size, pageofs); 159 160 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len, 161 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE); 162 if (ret) 163 goto out_page; 164 165 mutex_lock(&f->sem); 166 memset(&ri, 0, sizeof(ri)); 167 168 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK); 169 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE); 170 ri.totlen = cpu_to_je32(sizeof(ri)); 171 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4)); 172 173 ri.ino = cpu_to_je32(f->inocache->ino); 174 ri.version = cpu_to_je32(++f->highest_version); 175 ri.mode = cpu_to_jemode(inode->i_mode); 176 ri.uid = cpu_to_je16(i_uid_read(inode)); 177 ri.gid = cpu_to_je16(i_gid_read(inode)); 178 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs)); 179 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW()); 180 ri.offset = cpu_to_je32(inode->i_size); 181 ri.dsize = cpu_to_je32(pageofs - inode->i_size); 182 ri.csize = cpu_to_je32(0); 183 ri.compr = JFFS2_COMPR_ZERO; 184 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8)); 185 ri.data_crc = cpu_to_je32(0); 186 187 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL); 188 189 if (IS_ERR(fn)) { 190 ret = PTR_ERR(fn); 191 jffs2_complete_reservation(c); 192 mutex_unlock(&f->sem); 193 goto out_page; 194 } 195 ret = jffs2_add_full_dnode_to_inode(c, f, fn); 196 if (f->metadata) { 197 jffs2_mark_node_obsolete(c, f->metadata->raw); 198 jffs2_free_full_dnode(f->metadata); 199 f->metadata = NULL; 200 } 201 if (ret) { 202 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", 203 ret); 204 jffs2_mark_node_obsolete(c, fn->raw); 205 jffs2_free_full_dnode(fn); 206 jffs2_complete_reservation(c); 207 mutex_unlock(&f->sem); 208 goto out_page; 209 } 210 jffs2_complete_reservation(c); 211 inode->i_size = pageofs; 212 mutex_unlock(&f->sem); 213 } 214 215 /* 216 * Read in the page if it wasn't already present. Cannot optimize away 217 * the whole page write case until jffs2_write_end can handle the 218 * case of a short-copy. 219 */ 220 if (!PageUptodate(pg)) { 221 mutex_lock(&f->sem); 222 ret = jffs2_do_readpage_nolock(inode, pg); 223 mutex_unlock(&f->sem); 224 if (ret) 225 goto out_page; 226 } 227 jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags); 228 return ret; 229 230 out_page: 231 unlock_page(pg); 232 put_page(pg); 233 return ret; 234 } 235 236 static int jffs2_write_end(struct file *filp, struct address_space *mapping, 237 loff_t pos, unsigned len, unsigned copied, 238 struct page *pg, void *fsdata) 239 { 240 /* Actually commit the write from the page cache page we're looking at. 241 * For now, we write the full page out each time. It sucks, but it's simple 242 */ 243 struct inode *inode = mapping->host; 244 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 245 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 246 struct jffs2_raw_inode *ri; 247 unsigned start = pos & (PAGE_SIZE - 1); 248 unsigned end = start + copied; 249 unsigned aligned_start = start & ~3; 250 int ret = 0; 251 uint32_t writtenlen = 0; 252 253 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n", 254 __func__, inode->i_ino, pg->index << PAGE_SHIFT, 255 start, end, pg->flags); 256 257 /* We need to avoid deadlock with page_cache_read() in 258 jffs2_garbage_collect_pass(). So the page must be 259 up to date to prevent page_cache_read() from trying 260 to re-lock it. */ 261 BUG_ON(!PageUptodate(pg)); 262 263 if (end == PAGE_SIZE) { 264 /* When writing out the end of a page, write out the 265 _whole_ page. This helps to reduce the number of 266 nodes in files which have many short writes, like 267 syslog files. */ 268 aligned_start = 0; 269 } 270 271 ri = jffs2_alloc_raw_inode(); 272 273 if (!ri) { 274 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n", 275 __func__); 276 unlock_page(pg); 277 put_page(pg); 278 return -ENOMEM; 279 } 280 281 /* Set the fields that the generic jffs2_write_inode_range() code can't find */ 282 ri->ino = cpu_to_je32(inode->i_ino); 283 ri->mode = cpu_to_jemode(inode->i_mode); 284 ri->uid = cpu_to_je16(i_uid_read(inode)); 285 ri->gid = cpu_to_je16(i_gid_read(inode)); 286 ri->isize = cpu_to_je32((uint32_t)inode->i_size); 287 ri->atime = ri->ctime = ri->mtime = cpu_to_je32(JFFS2_NOW()); 288 289 /* In 2.4, it was already kmapped by generic_file_write(). Doesn't 290 hurt to do it again. The alternative is ifdefs, which are ugly. */ 291 kmap(pg); 292 293 ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start, 294 (pg->index << PAGE_SHIFT) + aligned_start, 295 end - aligned_start, &writtenlen); 296 297 kunmap(pg); 298 299 if (ret) { 300 /* There was an error writing. */ 301 SetPageError(pg); 302 } 303 304 /* Adjust writtenlen for the padding we did, so we don't confuse our caller */ 305 writtenlen -= min(writtenlen, (start - aligned_start)); 306 307 if (writtenlen) { 308 if (inode->i_size < pos + writtenlen) { 309 inode->i_size = pos + writtenlen; 310 inode->i_blocks = (inode->i_size + 511) >> 9; 311 312 inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime)); 313 } 314 } 315 316 jffs2_free_raw_inode(ri); 317 318 if (start+writtenlen < end) { 319 /* generic_file_write has written more to the page cache than we've 320 actually written to the medium. Mark the page !Uptodate so that 321 it gets reread */ 322 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n", 323 __func__); 324 SetPageError(pg); 325 ClearPageUptodate(pg); 326 } 327 328 jffs2_dbg(1, "%s() returning %d\n", 329 __func__, writtenlen > 0 ? writtenlen : ret); 330 unlock_page(pg); 331 put_page(pg); 332 return writtenlen > 0 ? writtenlen : ret; 333 } 334