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 jffs2_fsync(struct file * filp,loff_t start,loff_t end,int datasync)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 jffs2_do_readpage_nolock(struct inode * inode,struct page * pg)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 jffs2_do_readpage_unlock(struct inode * inode,struct page * pg)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 jffs2_readpage(struct file * filp,struct page * pg)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 jffs2_write_begin(struct file * filp,struct address_space * mapping,loff_t pos,unsigned len,unsigned flags,struct page ** pagep,void ** fsdata)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 pgoff_t index = pos >> PAGE_CACHE_SHIFT; 141 uint32_t pageofs = index << PAGE_CACHE_SHIFT; 142 int ret = 0; 143 144 pg = grab_cache_page_write_begin(mapping, index, flags); 145 if (!pg) 146 return -ENOMEM; 147 *pagep = pg; 148 149 jffs2_dbg(1, "%s()\n", __func__); 150 151 if (pageofs > inode->i_size) { 152 /* Make new hole frag from old EOF to new page */ 153 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 154 struct jffs2_raw_inode ri; 155 struct jffs2_full_dnode *fn; 156 uint32_t alloc_len; 157 158 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n", 159 (unsigned int)inode->i_size, pageofs); 160 161 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len, 162 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE); 163 if (ret) 164 goto out_page; 165 166 mutex_lock(&f->sem); 167 memset(&ri, 0, sizeof(ri)); 168 169 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK); 170 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE); 171 ri.totlen = cpu_to_je32(sizeof(ri)); 172 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4)); 173 174 ri.ino = cpu_to_je32(f->inocache->ino); 175 ri.version = cpu_to_je32(++f->highest_version); 176 ri.mode = cpu_to_jemode(inode->i_mode); 177 ri.uid = cpu_to_je16(i_uid_read(inode)); 178 ri.gid = cpu_to_je16(i_gid_read(inode)); 179 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs)); 180 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds()); 181 ri.offset = cpu_to_je32(inode->i_size); 182 ri.dsize = cpu_to_je32(pageofs - inode->i_size); 183 ri.csize = cpu_to_je32(0); 184 ri.compr = JFFS2_COMPR_ZERO; 185 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8)); 186 ri.data_crc = cpu_to_je32(0); 187 188 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL); 189 190 if (IS_ERR(fn)) { 191 ret = PTR_ERR(fn); 192 jffs2_complete_reservation(c); 193 mutex_unlock(&f->sem); 194 goto out_page; 195 } 196 ret = jffs2_add_full_dnode_to_inode(c, f, fn); 197 if (f->metadata) { 198 jffs2_mark_node_obsolete(c, f->metadata->raw); 199 jffs2_free_full_dnode(f->metadata); 200 f->metadata = NULL; 201 } 202 if (ret) { 203 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", 204 ret); 205 jffs2_mark_node_obsolete(c, fn->raw); 206 jffs2_free_full_dnode(fn); 207 jffs2_complete_reservation(c); 208 mutex_unlock(&f->sem); 209 goto out_page; 210 } 211 jffs2_complete_reservation(c); 212 inode->i_size = pageofs; 213 mutex_unlock(&f->sem); 214 } 215 216 /* 217 * Read in the page if it wasn't already present. Cannot optimize away 218 * the whole page write case until jffs2_write_end can handle the 219 * case of a short-copy. 220 */ 221 if (!PageUptodate(pg)) { 222 mutex_lock(&f->sem); 223 ret = jffs2_do_readpage_nolock(inode, pg); 224 mutex_unlock(&f->sem); 225 if (ret) 226 goto out_page; 227 } 228 jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags); 229 return ret; 230 231 out_page: 232 unlock_page(pg); 233 page_cache_release(pg); 234 return ret; 235 } 236 jffs2_write_end(struct file * filp,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * pg,void * fsdata)237 static int jffs2_write_end(struct file *filp, struct address_space *mapping, 238 loff_t pos, unsigned len, unsigned copied, 239 struct page *pg, void *fsdata) 240 { 241 /* Actually commit the write from the page cache page we're looking at. 242 * For now, we write the full page out each time. It sucks, but it's simple 243 */ 244 struct inode *inode = mapping->host; 245 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 246 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 247 struct jffs2_raw_inode *ri; 248 unsigned start = pos & (PAGE_CACHE_SIZE - 1); 249 unsigned end = start + copied; 250 unsigned aligned_start = start & ~3; 251 int ret = 0; 252 uint32_t writtenlen = 0; 253 254 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n", 255 __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT, 256 start, end, pg->flags); 257 258 /* We need to avoid deadlock with page_cache_read() in 259 jffs2_garbage_collect_pass(). So the page must be 260 up to date to prevent page_cache_read() from trying 261 to re-lock it. */ 262 BUG_ON(!PageUptodate(pg)); 263 264 if (end == PAGE_CACHE_SIZE) { 265 /* When writing out the end of a page, write out the 266 _whole_ page. This helps to reduce the number of 267 nodes in files which have many short writes, like 268 syslog files. */ 269 aligned_start = 0; 270 } 271 272 ri = jffs2_alloc_raw_inode(); 273 274 if (!ri) { 275 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n", 276 __func__); 277 unlock_page(pg); 278 page_cache_release(pg); 279 return -ENOMEM; 280 } 281 282 /* Set the fields that the generic jffs2_write_inode_range() code can't find */ 283 ri->ino = cpu_to_je32(inode->i_ino); 284 ri->mode = cpu_to_jemode(inode->i_mode); 285 ri->uid = cpu_to_je16(i_uid_read(inode)); 286 ri->gid = cpu_to_je16(i_gid_read(inode)); 287 ri->isize = cpu_to_je32((uint32_t)inode->i_size); 288 ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds()); 289 290 /* In 2.4, it was already kmapped by generic_file_write(). Doesn't 291 hurt to do it again. The alternative is ifdefs, which are ugly. */ 292 kmap(pg); 293 294 ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start, 295 (pg->index << PAGE_CACHE_SHIFT) + aligned_start, 296 end - aligned_start, &writtenlen); 297 298 kunmap(pg); 299 300 if (ret) { 301 /* There was an error writing. */ 302 SetPageError(pg); 303 } 304 305 /* Adjust writtenlen for the padding we did, so we don't confuse our caller */ 306 writtenlen -= min(writtenlen, (start - aligned_start)); 307 308 if (writtenlen) { 309 if (inode->i_size < pos + writtenlen) { 310 inode->i_size = pos + writtenlen; 311 inode->i_blocks = (inode->i_size + 511) >> 9; 312 313 inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime)); 314 } 315 } 316 317 jffs2_free_raw_inode(ri); 318 319 if (start+writtenlen < end) { 320 /* generic_file_write has written more to the page cache than we've 321 actually written to the medium. Mark the page !Uptodate so that 322 it gets reread */ 323 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n", 324 __func__); 325 SetPageError(pg); 326 ClearPageUptodate(pg); 327 } 328 329 jffs2_dbg(1, "%s() returning %d\n", 330 __func__, writtenlen > 0 ? writtenlen : ret); 331 unlock_page(pg); 332 page_cache_release(pg); 333 return writtenlen > 0 ? writtenlen : ret; 334 } 335