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(const struct kiocb *iocb, 25 struct address_space *mapping, 26 loff_t pos, unsigned len, unsigned copied, 27 struct folio *folio, void *fsdata); 28 static int jffs2_write_begin(const struct kiocb *iocb, 29 struct address_space *mapping, 30 loff_t pos, unsigned len, 31 struct folio **foliop, void **fsdata); 32 static int jffs2_read_folio(struct file *filp, struct folio *folio); 33 34 int jffs2_fsync(struct file *filp, loff_t start, loff_t end, int datasync) 35 { 36 struct inode *inode = filp->f_mapping->host; 37 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 38 int ret; 39 40 ret = file_write_and_wait_range(filp, start, end); 41 if (ret) 42 return ret; 43 44 inode_lock(inode); 45 /* Trigger GC to flush any pending writes for this inode */ 46 jffs2_flush_wbuf_gc(c, inode->i_ino); 47 inode_unlock(inode); 48 49 return 0; 50 } 51 52 const struct file_operations jffs2_file_operations = 53 { 54 .llseek = generic_file_llseek, 55 .open = generic_file_open, 56 .read_iter = generic_file_read_iter, 57 .write_iter = generic_file_write_iter, 58 .unlocked_ioctl=jffs2_ioctl, 59 .mmap_prepare = generic_file_readonly_mmap_prepare, 60 .fsync = jffs2_fsync, 61 .splice_read = filemap_splice_read, 62 .splice_write = iter_file_splice_write, 63 }; 64 65 /* jffs2_file_inode_operations */ 66 67 const struct inode_operations jffs2_file_inode_operations = 68 { 69 .get_inode_acl = jffs2_get_acl, 70 .set_acl = jffs2_set_acl, 71 .setattr = jffs2_setattr, 72 .listxattr = jffs2_listxattr, 73 }; 74 75 const struct address_space_operations jffs2_file_address_operations = 76 { 77 .read_folio = jffs2_read_folio, 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 folio *folio) 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 *kaddr; 87 int ret; 88 89 jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n", 90 __func__, inode->i_ino, folio->index << PAGE_SHIFT); 91 92 BUG_ON(!folio_test_locked(folio)); 93 94 kaddr = kmap_local_folio(folio, 0); 95 ret = jffs2_read_inode_range(c, f, kaddr, folio->index << PAGE_SHIFT, 96 PAGE_SIZE); 97 kunmap_local(kaddr); 98 99 if (!ret) 100 folio_mark_uptodate(folio); 101 102 flush_dcache_folio(folio); 103 104 jffs2_dbg(2, "readpage finished\n"); 105 return ret; 106 } 107 108 int __jffs2_read_folio(struct file *file, struct folio *folio) 109 { 110 int ret = jffs2_do_readpage_nolock(folio->mapping->host, folio); 111 folio_unlock(folio); 112 return ret; 113 } 114 115 static int jffs2_read_folio(struct file *file, struct folio *folio) 116 { 117 struct jffs2_inode_info *f = JFFS2_INODE_INFO(folio->mapping->host); 118 int ret; 119 120 mutex_lock(&f->sem); 121 ret = __jffs2_read_folio(file, folio); 122 mutex_unlock(&f->sem); 123 return ret; 124 } 125 126 static int jffs2_write_begin(const struct kiocb *iocb, 127 struct address_space *mapping, 128 loff_t pos, unsigned len, 129 struct folio **foliop, void **fsdata) 130 { 131 struct folio *folio; 132 struct inode *inode = mapping->host; 133 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 134 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 135 pgoff_t index = pos >> PAGE_SHIFT; 136 int ret = 0; 137 138 jffs2_dbg(1, "%s()\n", __func__); 139 140 if (pos > inode->i_size) { 141 /* Make new hole frag from old EOF to new position */ 142 struct jffs2_raw_inode ri; 143 struct jffs2_full_dnode *fn; 144 uint32_t alloc_len; 145 146 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new position\n", 147 (unsigned int)inode->i_size, (uint32_t)pos); 148 149 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len, 150 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE); 151 if (ret) 152 goto out_err; 153 154 mutex_lock(&f->sem); 155 memset(&ri, 0, sizeof(ri)); 156 157 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK); 158 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE); 159 ri.totlen = cpu_to_je32(sizeof(ri)); 160 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4)); 161 162 ri.ino = cpu_to_je32(f->inocache->ino); 163 ri.version = cpu_to_je32(++f->highest_version); 164 ri.mode = cpu_to_jemode(inode->i_mode); 165 ri.uid = cpu_to_je16(i_uid_read(inode)); 166 ri.gid = cpu_to_je16(i_gid_read(inode)); 167 ri.isize = cpu_to_je32((uint32_t)pos); 168 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW()); 169 ri.offset = cpu_to_je32(inode->i_size); 170 ri.dsize = cpu_to_je32((uint32_t)pos - inode->i_size); 171 ri.csize = cpu_to_je32(0); 172 ri.compr = JFFS2_COMPR_ZERO; 173 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8)); 174 ri.data_crc = cpu_to_je32(0); 175 176 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL); 177 178 if (IS_ERR(fn)) { 179 ret = PTR_ERR(fn); 180 jffs2_complete_reservation(c); 181 mutex_unlock(&f->sem); 182 goto out_err; 183 } 184 ret = jffs2_add_full_dnode_to_inode(c, f, fn); 185 if (f->metadata) { 186 jffs2_mark_node_obsolete(c, f->metadata->raw); 187 jffs2_free_full_dnode(f->metadata); 188 f->metadata = NULL; 189 } 190 if (ret) { 191 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", 192 ret); 193 jffs2_mark_node_obsolete(c, fn->raw); 194 jffs2_free_full_dnode(fn); 195 jffs2_complete_reservation(c); 196 mutex_unlock(&f->sem); 197 goto out_err; 198 } 199 jffs2_complete_reservation(c); 200 inode->i_size = pos; 201 mutex_unlock(&f->sem); 202 } 203 204 /* 205 * While getting a page and reading data in, lock c->alloc_sem until 206 * the page is Uptodate. Otherwise GC task may attempt to read the same 207 * page in read_cache_page(), which causes a deadlock. 208 */ 209 mutex_lock(&c->alloc_sem); 210 folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN, 211 mapping_gfp_mask(mapping)); 212 if (IS_ERR(folio)) { 213 ret = PTR_ERR(folio); 214 goto release_sem; 215 } 216 *foliop = folio; 217 218 /* 219 * Read in the folio if it wasn't already present. Cannot optimize away 220 * the whole folio write case until jffs2_write_end can handle the 221 * case of a short-copy. 222 */ 223 if (!folio_test_uptodate(folio)) { 224 mutex_lock(&f->sem); 225 ret = jffs2_do_readpage_nolock(inode, folio); 226 mutex_unlock(&f->sem); 227 if (ret) { 228 folio_unlock(folio); 229 folio_put(folio); 230 goto release_sem; 231 } 232 } 233 jffs2_dbg(1, "end write_begin(). folio->flags %lx\n", folio->flags); 234 235 release_sem: 236 mutex_unlock(&c->alloc_sem); 237 out_err: 238 return ret; 239 } 240 241 static int jffs2_write_end(const struct kiocb *iocb, 242 struct address_space *mapping, 243 loff_t pos, unsigned len, unsigned copied, 244 struct folio *folio, void *fsdata) 245 { 246 /* Actually commit the write from the page cache page we're looking at. 247 * For now, we write the full page out each time. It sucks, but it's simple 248 */ 249 struct inode *inode = mapping->host; 250 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 251 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 252 struct jffs2_raw_inode *ri; 253 unsigned start = pos & (PAGE_SIZE - 1); 254 unsigned end = start + copied; 255 unsigned aligned_start = start & ~3; 256 int ret = 0; 257 uint32_t writtenlen = 0; 258 void *buf; 259 260 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%llx, range %d-%d, flags %lx\n", 261 __func__, inode->i_ino, folio_pos(folio), 262 start, end, folio->flags); 263 264 /* We need to avoid deadlock with page_cache_read() in 265 jffs2_garbage_collect_pass(). So the folio must be 266 up to date to prevent page_cache_read() from trying 267 to re-lock it. */ 268 BUG_ON(!folio_test_uptodate(folio)); 269 270 if (end == PAGE_SIZE) { 271 /* When writing out the end of a page, write out the 272 _whole_ page. This helps to reduce the number of 273 nodes in files which have many short writes, like 274 syslog files. */ 275 aligned_start = 0; 276 } 277 278 ri = jffs2_alloc_raw_inode(); 279 280 if (!ri) { 281 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n", 282 __func__); 283 folio_unlock(folio); 284 folio_put(folio); 285 return -ENOMEM; 286 } 287 288 /* Set the fields that the generic jffs2_write_inode_range() code can't find */ 289 ri->ino = cpu_to_je32(inode->i_ino); 290 ri->mode = cpu_to_jemode(inode->i_mode); 291 ri->uid = cpu_to_je16(i_uid_read(inode)); 292 ri->gid = cpu_to_je16(i_gid_read(inode)); 293 ri->isize = cpu_to_je32((uint32_t)inode->i_size); 294 ri->atime = ri->ctime = ri->mtime = cpu_to_je32(JFFS2_NOW()); 295 296 buf = kmap_local_folio(folio, aligned_start); 297 ret = jffs2_write_inode_range(c, f, ri, buf, 298 folio_pos(folio) + aligned_start, 299 end - aligned_start, &writtenlen); 300 kunmap_local(buf); 301 302 if (ret) 303 mapping_set_error(mapping, ret); 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_set_mtime_to_ts(inode, 314 inode_set_ctime_to_ts(inode, 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 folio_clear_uptodate(folio); 327 } 328 329 jffs2_dbg(1, "%s() returning %d\n", 330 __func__, writtenlen > 0 ? writtenlen : ret); 331 folio_unlock(folio); 332 folio_put(folio); 333 return writtenlen > 0 ? writtenlen : ret; 334 } 335