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 folio *folio, void *fsdata); 27 static int jffs2_write_begin(struct file *filp, struct address_space *mapping, 28 loff_t pos, unsigned len, 29 struct folio **foliop, void **fsdata); 30 static int jffs2_read_folio(struct file *filp, struct folio *folio); 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 = filemap_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_inode_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 .read_folio = jffs2_read_folio, 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 folio *folio) 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 *kaddr; 85 int ret; 86 87 jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n", 88 __func__, inode->i_ino, folio->index << PAGE_SHIFT); 89 90 BUG_ON(!folio_test_locked(folio)); 91 92 kaddr = kmap_local_folio(folio, 0); 93 ret = jffs2_read_inode_range(c, f, kaddr, folio->index << PAGE_SHIFT, 94 PAGE_SIZE); 95 kunmap_local(kaddr); 96 97 if (!ret) 98 folio_mark_uptodate(folio); 99 100 flush_dcache_folio(folio); 101 102 jffs2_dbg(2, "readpage finished\n"); 103 return ret; 104 } 105 106 int __jffs2_read_folio(struct file *file, struct folio *folio) 107 { 108 int ret = jffs2_do_readpage_nolock(folio->mapping->host, folio); 109 folio_unlock(folio); 110 return ret; 111 } 112 113 static int jffs2_read_folio(struct file *file, struct folio *folio) 114 { 115 struct jffs2_inode_info *f = JFFS2_INODE_INFO(folio->mapping->host); 116 int ret; 117 118 mutex_lock(&f->sem); 119 ret = __jffs2_read_folio(file, folio); 120 mutex_unlock(&f->sem); 121 return ret; 122 } 123 124 static int jffs2_write_begin(struct file *filp, struct address_space *mapping, 125 loff_t pos, unsigned len, 126 struct folio **foliop, void **fsdata) 127 { 128 struct folio *folio; 129 struct inode *inode = mapping->host; 130 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 131 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 132 pgoff_t index = pos >> PAGE_SHIFT; 133 int ret = 0; 134 135 jffs2_dbg(1, "%s()\n", __func__); 136 137 if (pos > inode->i_size) { 138 /* Make new hole frag from old EOF to new position */ 139 struct jffs2_raw_inode ri; 140 struct jffs2_full_dnode *fn; 141 uint32_t alloc_len; 142 143 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new position\n", 144 (unsigned int)inode->i_size, (uint32_t)pos); 145 146 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len, 147 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE); 148 if (ret) 149 goto out_err; 150 151 mutex_lock(&f->sem); 152 memset(&ri, 0, sizeof(ri)); 153 154 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK); 155 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE); 156 ri.totlen = cpu_to_je32(sizeof(ri)); 157 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4)); 158 159 ri.ino = cpu_to_je32(f->inocache->ino); 160 ri.version = cpu_to_je32(++f->highest_version); 161 ri.mode = cpu_to_jemode(inode->i_mode); 162 ri.uid = cpu_to_je16(i_uid_read(inode)); 163 ri.gid = cpu_to_je16(i_gid_read(inode)); 164 ri.isize = cpu_to_je32((uint32_t)pos); 165 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW()); 166 ri.offset = cpu_to_je32(inode->i_size); 167 ri.dsize = cpu_to_je32((uint32_t)pos - inode->i_size); 168 ri.csize = cpu_to_je32(0); 169 ri.compr = JFFS2_COMPR_ZERO; 170 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8)); 171 ri.data_crc = cpu_to_je32(0); 172 173 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL); 174 175 if (IS_ERR(fn)) { 176 ret = PTR_ERR(fn); 177 jffs2_complete_reservation(c); 178 mutex_unlock(&f->sem); 179 goto out_err; 180 } 181 ret = jffs2_add_full_dnode_to_inode(c, f, fn); 182 if (f->metadata) { 183 jffs2_mark_node_obsolete(c, f->metadata->raw); 184 jffs2_free_full_dnode(f->metadata); 185 f->metadata = NULL; 186 } 187 if (ret) { 188 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", 189 ret); 190 jffs2_mark_node_obsolete(c, fn->raw); 191 jffs2_free_full_dnode(fn); 192 jffs2_complete_reservation(c); 193 mutex_unlock(&f->sem); 194 goto out_err; 195 } 196 jffs2_complete_reservation(c); 197 inode->i_size = pos; 198 mutex_unlock(&f->sem); 199 } 200 201 /* 202 * While getting a page and reading data in, lock c->alloc_sem until 203 * the page is Uptodate. Otherwise GC task may attempt to read the same 204 * page in read_cache_page(), which causes a deadlock. 205 */ 206 mutex_lock(&c->alloc_sem); 207 folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN, 208 mapping_gfp_mask(mapping)); 209 if (IS_ERR(folio)) { 210 ret = PTR_ERR(folio); 211 goto release_sem; 212 } 213 *foliop = folio; 214 215 /* 216 * Read in the folio if it wasn't already present. Cannot optimize away 217 * the whole folio write case until jffs2_write_end can handle the 218 * case of a short-copy. 219 */ 220 if (!folio_test_uptodate(folio)) { 221 mutex_lock(&f->sem); 222 ret = jffs2_do_readpage_nolock(inode, folio); 223 mutex_unlock(&f->sem); 224 if (ret) { 225 folio_unlock(folio); 226 folio_put(folio); 227 goto release_sem; 228 } 229 } 230 jffs2_dbg(1, "end write_begin(). folio->flags %lx\n", folio->flags); 231 232 release_sem: 233 mutex_unlock(&c->alloc_sem); 234 out_err: 235 return ret; 236 } 237 238 static int jffs2_write_end(struct file *filp, struct address_space *mapping, 239 loff_t pos, unsigned len, unsigned copied, 240 struct folio *folio, void *fsdata) 241 { 242 /* Actually commit the write from the page cache page we're looking at. 243 * For now, we write the full page out each time. It sucks, but it's simple 244 */ 245 struct inode *inode = mapping->host; 246 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 247 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 248 struct jffs2_raw_inode *ri; 249 unsigned start = pos & (PAGE_SIZE - 1); 250 unsigned end = start + copied; 251 unsigned aligned_start = start & ~3; 252 int ret = 0; 253 uint32_t writtenlen = 0; 254 void *buf; 255 256 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%llx, range %d-%d, flags %lx\n", 257 __func__, inode->i_ino, folio_pos(folio), 258 start, end, folio->flags); 259 260 /* We need to avoid deadlock with page_cache_read() in 261 jffs2_garbage_collect_pass(). So the folio must be 262 up to date to prevent page_cache_read() from trying 263 to re-lock it. */ 264 BUG_ON(!folio_test_uptodate(folio)); 265 266 if (end == PAGE_SIZE) { 267 /* When writing out the end of a page, write out the 268 _whole_ page. This helps to reduce the number of 269 nodes in files which have many short writes, like 270 syslog files. */ 271 aligned_start = 0; 272 } 273 274 ri = jffs2_alloc_raw_inode(); 275 276 if (!ri) { 277 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n", 278 __func__); 279 folio_unlock(folio); 280 folio_put(folio); 281 return -ENOMEM; 282 } 283 284 /* Set the fields that the generic jffs2_write_inode_range() code can't find */ 285 ri->ino = cpu_to_je32(inode->i_ino); 286 ri->mode = cpu_to_jemode(inode->i_mode); 287 ri->uid = cpu_to_je16(i_uid_read(inode)); 288 ri->gid = cpu_to_je16(i_gid_read(inode)); 289 ri->isize = cpu_to_je32((uint32_t)inode->i_size); 290 ri->atime = ri->ctime = ri->mtime = cpu_to_je32(JFFS2_NOW()); 291 292 buf = kmap_local_folio(folio, aligned_start); 293 ret = jffs2_write_inode_range(c, f, ri, buf, 294 folio_pos(folio) + aligned_start, 295 end - aligned_start, &writtenlen); 296 kunmap_local(buf); 297 298 if (ret) 299 mapping_set_error(mapping, ret); 300 301 /* Adjust writtenlen for the padding we did, so we don't confuse our caller */ 302 writtenlen -= min(writtenlen, (start - aligned_start)); 303 304 if (writtenlen) { 305 if (inode->i_size < pos + writtenlen) { 306 inode->i_size = pos + writtenlen; 307 inode->i_blocks = (inode->i_size + 511) >> 9; 308 309 inode_set_mtime_to_ts(inode, 310 inode_set_ctime_to_ts(inode, ITIME(je32_to_cpu(ri->ctime)))); 311 } 312 } 313 314 jffs2_free_raw_inode(ri); 315 316 if (start+writtenlen < end) { 317 /* generic_file_write has written more to the page cache than we've 318 actually written to the medium. Mark the page !Uptodate so that 319 it gets reread */ 320 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n", 321 __func__); 322 folio_clear_uptodate(folio); 323 } 324 325 jffs2_dbg(1, "%s() returning %d\n", 326 __func__, writtenlen > 0 ? writtenlen : ret); 327 folio_unlock(folio); 328 folio_put(folio); 329 return writtenlen > 0 ? writtenlen : ret; 330 } 331