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/filelock.h> 18 #include <linux/time.h> 19 #include <linux/pagemap.h> 20 #include <linux/highmem.h> 21 #include <linux/crc32.h> 22 #include <linux/jffs2.h> 23 #include "nodelist.h" 24 25 static int jffs2_write_end(const struct kiocb *iocb, 26 struct address_space *mapping, 27 loff_t pos, unsigned len, unsigned copied, 28 struct folio *folio, void *fsdata); 29 static int jffs2_write_begin(const struct kiocb *iocb, 30 struct address_space *mapping, 31 loff_t pos, unsigned len, 32 struct folio **foliop, void **fsdata); 33 static int jffs2_read_folio(struct file *filp, struct folio *folio); 34 35 int jffs2_fsync(struct file *filp, loff_t start, loff_t end, int datasync) 36 { 37 struct inode *inode = filp->f_mapping->host; 38 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 39 int ret; 40 41 ret = file_write_and_wait_range(filp, start, end); 42 if (ret) 43 return ret; 44 45 inode_lock(inode); 46 /* Trigger GC to flush any pending writes for this inode */ 47 jffs2_flush_wbuf_gc(c, inode->i_ino); 48 inode_unlock(inode); 49 50 return 0; 51 } 52 53 const struct file_operations jffs2_file_operations = 54 { 55 .llseek = generic_file_llseek, 56 .open = generic_file_open, 57 .read_iter = generic_file_read_iter, 58 .write_iter = generic_file_write_iter, 59 .unlocked_ioctl=jffs2_ioctl, 60 .mmap_prepare = generic_file_readonly_mmap_prepare, 61 .fsync = jffs2_fsync, 62 .splice_read = filemap_splice_read, 63 .splice_write = iter_file_splice_write, 64 .setlease = generic_setlease, 65 }; 66 67 /* jffs2_file_inode_operations */ 68 69 const struct inode_operations jffs2_file_inode_operations = 70 { 71 .get_inode_acl = jffs2_get_acl, 72 .set_acl = jffs2_set_acl, 73 .setattr = jffs2_setattr, 74 .listxattr = jffs2_listxattr, 75 }; 76 77 const struct address_space_operations jffs2_file_address_operations = 78 { 79 .read_folio = jffs2_read_folio, 80 .write_begin = jffs2_write_begin, 81 .write_end = jffs2_write_end, 82 }; 83 84 static int jffs2_do_readpage_nolock(struct inode *inode, struct folio *folio) 85 { 86 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 87 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 88 unsigned char *kaddr; 89 int ret; 90 91 jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n", 92 __func__, inode->i_ino, folio->index << PAGE_SHIFT); 93 94 BUG_ON(!folio_test_locked(folio)); 95 96 kaddr = kmap_local_folio(folio, 0); 97 ret = jffs2_read_inode_range(c, f, kaddr, folio->index << PAGE_SHIFT, 98 PAGE_SIZE); 99 kunmap_local(kaddr); 100 101 if (!ret) 102 folio_mark_uptodate(folio); 103 104 flush_dcache_folio(folio); 105 106 jffs2_dbg(2, "readpage finished\n"); 107 return ret; 108 } 109 110 int __jffs2_read_folio(struct file *file, struct folio *folio) 111 { 112 int ret = jffs2_do_readpage_nolock(folio->mapping->host, folio); 113 folio_unlock(folio); 114 return ret; 115 } 116 117 static int jffs2_read_folio(struct file *file, struct folio *folio) 118 { 119 struct jffs2_inode_info *f = JFFS2_INODE_INFO(folio->mapping->host); 120 int ret; 121 122 mutex_lock(&f->sem); 123 ret = __jffs2_read_folio(file, folio); 124 mutex_unlock(&f->sem); 125 return ret; 126 } 127 128 static int jffs2_write_begin(const struct kiocb *iocb, 129 struct address_space *mapping, 130 loff_t pos, unsigned len, 131 struct folio **foliop, void **fsdata) 132 { 133 struct folio *folio; 134 struct inode *inode = mapping->host; 135 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 136 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 137 pgoff_t index = pos >> PAGE_SHIFT; 138 int ret = 0; 139 140 jffs2_dbg(1, "%s()\n", __func__); 141 142 if (pos > inode->i_size) { 143 /* Make new hole frag from old EOF to new position */ 144 struct jffs2_raw_inode ri; 145 struct jffs2_full_dnode *fn; 146 uint32_t alloc_len; 147 148 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new position\n", 149 (unsigned int)inode->i_size, (uint32_t)pos); 150 151 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len, 152 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE); 153 if (ret) 154 goto out_err; 155 156 mutex_lock(&f->sem); 157 memset(&ri, 0, sizeof(ri)); 158 159 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK); 160 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE); 161 ri.totlen = cpu_to_je32(sizeof(ri)); 162 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4)); 163 164 ri.ino = cpu_to_je32(f->inocache->ino); 165 ri.version = cpu_to_je32(++f->highest_version); 166 ri.mode = cpu_to_jemode(inode->i_mode); 167 ri.uid = cpu_to_je16(i_uid_read(inode)); 168 ri.gid = cpu_to_je16(i_gid_read(inode)); 169 ri.isize = cpu_to_je32((uint32_t)pos); 170 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW()); 171 ri.offset = cpu_to_je32(inode->i_size); 172 ri.dsize = cpu_to_je32((uint32_t)pos - inode->i_size); 173 ri.csize = cpu_to_je32(0); 174 ri.compr = JFFS2_COMPR_ZERO; 175 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8)); 176 ri.data_crc = cpu_to_je32(0); 177 178 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL); 179 180 if (IS_ERR(fn)) { 181 ret = PTR_ERR(fn); 182 jffs2_complete_reservation(c); 183 mutex_unlock(&f->sem); 184 goto out_err; 185 } 186 ret = jffs2_add_full_dnode_to_inode(c, f, fn); 187 if (f->metadata) { 188 jffs2_mark_node_obsolete(c, f->metadata->raw); 189 jffs2_free_full_dnode(f->metadata); 190 f->metadata = NULL; 191 } 192 if (ret) { 193 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", 194 ret); 195 jffs2_mark_node_obsolete(c, fn->raw); 196 jffs2_free_full_dnode(fn); 197 jffs2_complete_reservation(c); 198 mutex_unlock(&f->sem); 199 goto out_err; 200 } 201 jffs2_complete_reservation(c); 202 inode->i_size = pos; 203 mutex_unlock(&f->sem); 204 } 205 206 /* 207 * While getting a page and reading data in, lock c->alloc_sem until 208 * the page is Uptodate. Otherwise GC task may attempt to read the same 209 * page in read_cache_page(), which causes a deadlock. 210 */ 211 mutex_lock(&c->alloc_sem); 212 folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN, 213 mapping_gfp_mask(mapping)); 214 if (IS_ERR(folio)) { 215 ret = PTR_ERR(folio); 216 goto release_sem; 217 } 218 *foliop = folio; 219 220 /* 221 * Read in the folio if it wasn't already present. Cannot optimize away 222 * the whole folio write case until jffs2_write_end can handle the 223 * case of a short-copy. 224 */ 225 if (!folio_test_uptodate(folio)) { 226 mutex_lock(&f->sem); 227 ret = jffs2_do_readpage_nolock(inode, folio); 228 mutex_unlock(&f->sem); 229 if (ret) { 230 folio_unlock(folio); 231 folio_put(folio); 232 goto release_sem; 233 } 234 } 235 jffs2_dbg(1, "end write_begin(). folio->flags %lx\n", folio->flags.f); 236 237 release_sem: 238 mutex_unlock(&c->alloc_sem); 239 out_err: 240 return ret; 241 } 242 243 static int jffs2_write_end(const struct kiocb *iocb, 244 struct address_space *mapping, 245 loff_t pos, unsigned len, unsigned copied, 246 struct folio *folio, void *fsdata) 247 { 248 /* Actually commit the write from the page cache page we're looking at. 249 * For now, we write the full page out each time. It sucks, but it's simple 250 */ 251 struct inode *inode = mapping->host; 252 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 253 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 254 struct jffs2_raw_inode *ri; 255 unsigned start = pos & (PAGE_SIZE - 1); 256 unsigned end = start + copied; 257 unsigned aligned_start = start & ~3; 258 int ret = 0; 259 uint32_t writtenlen = 0; 260 void *buf; 261 262 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%llx, range %d-%d, flags %lx\n", 263 __func__, inode->i_ino, folio_pos(folio), 264 start, end, folio->flags.f); 265 266 /* We need to avoid deadlock with page_cache_read() in 267 jffs2_garbage_collect_pass(). So the folio must be 268 up to date to prevent page_cache_read() from trying 269 to re-lock it. */ 270 BUG_ON(!folio_test_uptodate(folio)); 271 272 if (end == PAGE_SIZE) { 273 /* When writing out the end of a page, write out the 274 _whole_ page. This helps to reduce the number of 275 nodes in files which have many short writes, like 276 syslog files. */ 277 aligned_start = 0; 278 } 279 280 ri = jffs2_alloc_raw_inode(); 281 282 if (!ri) { 283 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n", 284 __func__); 285 folio_unlock(folio); 286 folio_put(folio); 287 return -ENOMEM; 288 } 289 290 /* Set the fields that the generic jffs2_write_inode_range() code can't find */ 291 ri->ino = cpu_to_je32(inode->i_ino); 292 ri->mode = cpu_to_jemode(inode->i_mode); 293 ri->uid = cpu_to_je16(i_uid_read(inode)); 294 ri->gid = cpu_to_je16(i_gid_read(inode)); 295 ri->isize = cpu_to_je32((uint32_t)inode->i_size); 296 ri->atime = ri->ctime = ri->mtime = cpu_to_je32(JFFS2_NOW()); 297 298 buf = kmap_local_folio(folio, aligned_start); 299 ret = jffs2_write_inode_range(c, f, ri, buf, 300 folio_pos(folio) + aligned_start, 301 end - aligned_start, &writtenlen); 302 kunmap_local(buf); 303 304 if (ret) 305 mapping_set_error(mapping, ret); 306 307 /* Adjust writtenlen for the padding we did, so we don't confuse our caller */ 308 writtenlen -= min(writtenlen, (start - aligned_start)); 309 310 if (writtenlen) { 311 if (inode->i_size < pos + writtenlen) { 312 inode->i_size = pos + writtenlen; 313 inode->i_blocks = (inode->i_size + 511) >> 9; 314 315 inode_set_mtime_to_ts(inode, 316 inode_set_ctime_to_ts(inode, 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 folio_clear_uptodate(folio); 329 } 330 331 jffs2_dbg(1, "%s() returning %d\n", 332 __func__, writtenlen > 0 ? writtenlen : ret); 333 folio_unlock(folio); 334 folio_put(folio); 335 return writtenlen > 0 ? writtenlen : ret; 336 } 337