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 }; 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 .listxattr = jffs2_listxattr, 70 }; 71 72 const struct address_space_operations jffs2_file_address_operations = 73 { 74 .readpage = jffs2_readpage, 75 .write_begin = jffs2_write_begin, 76 .write_end = jffs2_write_end, 77 }; 78 79 static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg) 80 { 81 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 82 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 83 unsigned char *pg_buf; 84 int ret; 85 86 jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n", 87 __func__, inode->i_ino, pg->index << PAGE_SHIFT); 88 89 BUG_ON(!PageLocked(pg)); 90 91 pg_buf = kmap(pg); 92 /* FIXME: Can kmap fail? */ 93 94 ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_SHIFT, 95 PAGE_SIZE); 96 97 if (ret) { 98 ClearPageUptodate(pg); 99 SetPageError(pg); 100 } else { 101 SetPageUptodate(pg); 102 ClearPageError(pg); 103 } 104 105 flush_dcache_page(pg); 106 kunmap(pg); 107 108 jffs2_dbg(2, "readpage finished\n"); 109 return ret; 110 } 111 112 int jffs2_do_readpage_unlock(struct inode *inode, struct page *pg) 113 { 114 int ret = jffs2_do_readpage_nolock(inode, pg); 115 unlock_page(pg); 116 return ret; 117 } 118 119 120 static int jffs2_readpage (struct file *filp, struct page *pg) 121 { 122 struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host); 123 int ret; 124 125 mutex_lock(&f->sem); 126 ret = jffs2_do_readpage_unlock(pg->mapping->host, pg); 127 mutex_unlock(&f->sem); 128 return ret; 129 } 130 131 static int jffs2_write_begin(struct file *filp, struct address_space *mapping, 132 loff_t pos, unsigned len, unsigned flags, 133 struct page **pagep, void **fsdata) 134 { 135 struct page *pg; 136 struct inode *inode = mapping->host; 137 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 138 pgoff_t index = pos >> PAGE_SHIFT; 139 uint32_t pageofs = index << PAGE_SHIFT; 140 int ret = 0; 141 142 pg = grab_cache_page_write_begin(mapping, index, flags); 143 if (!pg) 144 return -ENOMEM; 145 *pagep = pg; 146 147 jffs2_dbg(1, "%s()\n", __func__); 148 149 if (pageofs > inode->i_size) { 150 /* Make new hole frag from old EOF to new page */ 151 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 152 struct jffs2_raw_inode ri; 153 struct jffs2_full_dnode *fn; 154 uint32_t alloc_len; 155 156 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n", 157 (unsigned int)inode->i_size, pageofs); 158 159 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len, 160 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE); 161 if (ret) 162 goto out_page; 163 164 mutex_lock(&f->sem); 165 memset(&ri, 0, sizeof(ri)); 166 167 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK); 168 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE); 169 ri.totlen = cpu_to_je32(sizeof(ri)); 170 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4)); 171 172 ri.ino = cpu_to_je32(f->inocache->ino); 173 ri.version = cpu_to_je32(++f->highest_version); 174 ri.mode = cpu_to_jemode(inode->i_mode); 175 ri.uid = cpu_to_je16(i_uid_read(inode)); 176 ri.gid = cpu_to_je16(i_gid_read(inode)); 177 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs)); 178 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW()); 179 ri.offset = cpu_to_je32(inode->i_size); 180 ri.dsize = cpu_to_je32(pageofs - inode->i_size); 181 ri.csize = cpu_to_je32(0); 182 ri.compr = JFFS2_COMPR_ZERO; 183 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8)); 184 ri.data_crc = cpu_to_je32(0); 185 186 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL); 187 188 if (IS_ERR(fn)) { 189 ret = PTR_ERR(fn); 190 jffs2_complete_reservation(c); 191 mutex_unlock(&f->sem); 192 goto out_page; 193 } 194 ret = jffs2_add_full_dnode_to_inode(c, f, fn); 195 if (f->metadata) { 196 jffs2_mark_node_obsolete(c, f->metadata->raw); 197 jffs2_free_full_dnode(f->metadata); 198 f->metadata = NULL; 199 } 200 if (ret) { 201 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", 202 ret); 203 jffs2_mark_node_obsolete(c, fn->raw); 204 jffs2_free_full_dnode(fn); 205 jffs2_complete_reservation(c); 206 mutex_unlock(&f->sem); 207 goto out_page; 208 } 209 jffs2_complete_reservation(c); 210 inode->i_size = pageofs; 211 mutex_unlock(&f->sem); 212 } 213 214 /* 215 * Read in the page if it wasn't already present. Cannot optimize away 216 * the whole page write case until jffs2_write_end can handle the 217 * case of a short-copy. 218 */ 219 if (!PageUptodate(pg)) { 220 mutex_lock(&f->sem); 221 ret = jffs2_do_readpage_nolock(inode, pg); 222 mutex_unlock(&f->sem); 223 if (ret) 224 goto out_page; 225 } 226 jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags); 227 return ret; 228 229 out_page: 230 unlock_page(pg); 231 put_page(pg); 232 return ret; 233 } 234 235 static int jffs2_write_end(struct file *filp, struct address_space *mapping, 236 loff_t pos, unsigned len, unsigned copied, 237 struct page *pg, void *fsdata) 238 { 239 /* Actually commit the write from the page cache page we're looking at. 240 * For now, we write the full page out each time. It sucks, but it's simple 241 */ 242 struct inode *inode = mapping->host; 243 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 244 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 245 struct jffs2_raw_inode *ri; 246 unsigned start = pos & (PAGE_SIZE - 1); 247 unsigned end = start + copied; 248 unsigned aligned_start = start & ~3; 249 int ret = 0; 250 uint32_t writtenlen = 0; 251 252 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n", 253 __func__, inode->i_ino, pg->index << PAGE_SHIFT, 254 start, end, pg->flags); 255 256 /* We need to avoid deadlock with page_cache_read() in 257 jffs2_garbage_collect_pass(). So the page must be 258 up to date to prevent page_cache_read() from trying 259 to re-lock it. */ 260 BUG_ON(!PageUptodate(pg)); 261 262 if (end == PAGE_SIZE) { 263 /* When writing out the end of a page, write out the 264 _whole_ page. This helps to reduce the number of 265 nodes in files which have many short writes, like 266 syslog files. */ 267 aligned_start = 0; 268 } 269 270 ri = jffs2_alloc_raw_inode(); 271 272 if (!ri) { 273 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n", 274 __func__); 275 unlock_page(pg); 276 put_page(pg); 277 return -ENOMEM; 278 } 279 280 /* Set the fields that the generic jffs2_write_inode_range() code can't find */ 281 ri->ino = cpu_to_je32(inode->i_ino); 282 ri->mode = cpu_to_jemode(inode->i_mode); 283 ri->uid = cpu_to_je16(i_uid_read(inode)); 284 ri->gid = cpu_to_je16(i_gid_read(inode)); 285 ri->isize = cpu_to_je32((uint32_t)inode->i_size); 286 ri->atime = ri->ctime = ri->mtime = cpu_to_je32(JFFS2_NOW()); 287 288 /* In 2.4, it was already kmapped by generic_file_write(). Doesn't 289 hurt to do it again. The alternative is ifdefs, which are ugly. */ 290 kmap(pg); 291 292 ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start, 293 (pg->index << PAGE_SHIFT) + aligned_start, 294 end - aligned_start, &writtenlen); 295 296 kunmap(pg); 297 298 if (ret) { 299 /* There was an error writing. */ 300 SetPageError(pg); 301 } 302 303 /* Adjust writtenlen for the padding we did, so we don't confuse our caller */ 304 writtenlen -= min(writtenlen, (start - aligned_start)); 305 306 if (writtenlen) { 307 if (inode->i_size < pos + writtenlen) { 308 inode->i_size = pos + writtenlen; 309 inode->i_blocks = (inode->i_size + 511) >> 9; 310 311 inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime)); 312 } 313 } 314 315 jffs2_free_raw_inode(ri); 316 317 if (start+writtenlen < end) { 318 /* generic_file_write has written more to the page cache than we've 319 actually written to the medium. Mark the page !Uptodate so that 320 it gets reread */ 321 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n", 322 __func__); 323 SetPageError(pg); 324 ClearPageUptodate(pg); 325 } 326 327 jffs2_dbg(1, "%s() returning %d\n", 328 __func__, writtenlen > 0 ? writtenlen : ret); 329 unlock_page(pg); 330 put_page(pg); 331 return writtenlen > 0 ? writtenlen : ret; 332 } 333