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, 29 struct page **pagep, 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 page *pg) 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 *pg_buf; 85 int ret; 86 87 jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n", 88 __func__, inode->i_ino, pg->index << PAGE_SHIFT); 89 90 BUG_ON(!PageLocked(pg)); 91 92 pg_buf = kmap(pg); 93 /* FIXME: Can kmap fail? */ 94 95 ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_SHIFT, 96 PAGE_SIZE); 97 98 if (ret) { 99 ClearPageUptodate(pg); 100 SetPageError(pg); 101 } else { 102 SetPageUptodate(pg); 103 ClearPageError(pg); 104 } 105 106 flush_dcache_page(pg); 107 kunmap(pg); 108 109 jffs2_dbg(2, "readpage finished\n"); 110 return ret; 111 } 112 113 int __jffs2_read_folio(struct file *file, struct folio *folio) 114 { 115 int ret = jffs2_do_readpage_nolock(folio->mapping->host, &folio->page); 116 folio_unlock(folio); 117 return ret; 118 } 119 120 static int jffs2_read_folio(struct file *file, struct folio *folio) 121 { 122 struct jffs2_inode_info *f = JFFS2_INODE_INFO(folio->mapping->host); 123 int ret; 124 125 mutex_lock(&f->sem); 126 ret = __jffs2_read_folio(file, folio); 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, 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 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 139 pgoff_t index = pos >> PAGE_SHIFT; 140 int ret = 0; 141 142 jffs2_dbg(1, "%s()\n", __func__); 143 144 if (pos > inode->i_size) { 145 /* Make new hole frag from old EOF to new position */ 146 struct jffs2_raw_inode ri; 147 struct jffs2_full_dnode *fn; 148 uint32_t alloc_len; 149 150 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new position\n", 151 (unsigned int)inode->i_size, (uint32_t)pos); 152 153 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len, 154 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE); 155 if (ret) 156 goto out_err; 157 158 mutex_lock(&f->sem); 159 memset(&ri, 0, sizeof(ri)); 160 161 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK); 162 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE); 163 ri.totlen = cpu_to_je32(sizeof(ri)); 164 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4)); 165 166 ri.ino = cpu_to_je32(f->inocache->ino); 167 ri.version = cpu_to_je32(++f->highest_version); 168 ri.mode = cpu_to_jemode(inode->i_mode); 169 ri.uid = cpu_to_je16(i_uid_read(inode)); 170 ri.gid = cpu_to_je16(i_gid_read(inode)); 171 ri.isize = cpu_to_je32((uint32_t)pos); 172 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW()); 173 ri.offset = cpu_to_je32(inode->i_size); 174 ri.dsize = cpu_to_je32((uint32_t)pos - inode->i_size); 175 ri.csize = cpu_to_je32(0); 176 ri.compr = JFFS2_COMPR_ZERO; 177 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8)); 178 ri.data_crc = cpu_to_je32(0); 179 180 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL); 181 182 if (IS_ERR(fn)) { 183 ret = PTR_ERR(fn); 184 jffs2_complete_reservation(c); 185 mutex_unlock(&f->sem); 186 goto out_err; 187 } 188 ret = jffs2_add_full_dnode_to_inode(c, f, fn); 189 if (f->metadata) { 190 jffs2_mark_node_obsolete(c, f->metadata->raw); 191 jffs2_free_full_dnode(f->metadata); 192 f->metadata = NULL; 193 } 194 if (ret) { 195 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", 196 ret); 197 jffs2_mark_node_obsolete(c, fn->raw); 198 jffs2_free_full_dnode(fn); 199 jffs2_complete_reservation(c); 200 mutex_unlock(&f->sem); 201 goto out_err; 202 } 203 jffs2_complete_reservation(c); 204 inode->i_size = pos; 205 mutex_unlock(&f->sem); 206 } 207 208 /* 209 * While getting a page and reading data in, lock c->alloc_sem until 210 * the page is Uptodate. Otherwise GC task may attempt to read the same 211 * page in read_cache_page(), which causes a deadlock. 212 */ 213 mutex_lock(&c->alloc_sem); 214 pg = grab_cache_page_write_begin(mapping, index); 215 if (!pg) { 216 ret = -ENOMEM; 217 goto release_sem; 218 } 219 *pagep = pg; 220 221 /* 222 * Read in the page if it wasn't already present. Cannot optimize away 223 * the whole page write case until jffs2_write_end can handle the 224 * case of a short-copy. 225 */ 226 if (!PageUptodate(pg)) { 227 mutex_lock(&f->sem); 228 ret = jffs2_do_readpage_nolock(inode, pg); 229 mutex_unlock(&f->sem); 230 if (ret) { 231 unlock_page(pg); 232 put_page(pg); 233 goto release_sem; 234 } 235 } 236 jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags); 237 238 release_sem: 239 mutex_unlock(&c->alloc_sem); 240 out_err: 241 return ret; 242 } 243 244 static int jffs2_write_end(struct file *filp, struct address_space *mapping, 245 loff_t pos, unsigned len, unsigned copied, 246 struct page *pg, 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; 260 261 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n", 262 __func__, inode->i_ino, pg->index << PAGE_SHIFT, 263 start, end, pg->flags); 264 265 /* We need to avoid deadlock with page_cache_read() in 266 jffs2_garbage_collect_pass(). So the page must be 267 up to date to prevent page_cache_read() from trying 268 to re-lock it. */ 269 BUG_ON(!PageUptodate(pg)); 270 271 if (end == PAGE_SIZE) { 272 /* When writing out the end of a page, write out the 273 _whole_ page. This helps to reduce the number of 274 nodes in files which have many short writes, like 275 syslog files. */ 276 aligned_start = 0; 277 } 278 279 ri = jffs2_alloc_raw_inode(); 280 281 if (!ri) { 282 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n", 283 __func__); 284 unlock_page(pg); 285 put_page(pg); 286 return -ENOMEM; 287 } 288 289 /* Set the fields that the generic jffs2_write_inode_range() code can't find */ 290 ri->ino = cpu_to_je32(inode->i_ino); 291 ri->mode = cpu_to_jemode(inode->i_mode); 292 ri->uid = cpu_to_je16(i_uid_read(inode)); 293 ri->gid = cpu_to_je16(i_gid_read(inode)); 294 ri->isize = cpu_to_je32((uint32_t)inode->i_size); 295 ri->atime = ri->ctime = ri->mtime = cpu_to_je32(JFFS2_NOW()); 296 297 /* In 2.4, it was already kmapped by generic_file_write(). Doesn't 298 hurt to do it again. The alternative is ifdefs, which are ugly. */ 299 kmap(pg); 300 301 ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start, 302 (pg->index << PAGE_SHIFT) + aligned_start, 303 end - aligned_start, &writtenlen); 304 305 kunmap(pg); 306 307 if (ret) { 308 /* There was an error writing. */ 309 SetPageError(pg); 310 } 311 312 /* Adjust writtenlen for the padding we did, so we don't confuse our caller */ 313 writtenlen -= min(writtenlen, (start - aligned_start)); 314 315 if (writtenlen) { 316 if (inode->i_size < pos + writtenlen) { 317 inode->i_size = pos + writtenlen; 318 inode->i_blocks = (inode->i_size + 511) >> 9; 319 320 inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime)); 321 } 322 } 323 324 jffs2_free_raw_inode(ri); 325 326 if (start+writtenlen < end) { 327 /* generic_file_write has written more to the page cache than we've 328 actually written to the medium. Mark the page !Uptodate so that 329 it gets reread */ 330 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n", 331 __func__); 332 SetPageError(pg); 333 ClearPageUptodate(pg); 334 } 335 336 jffs2_dbg(1, "%s() returning %d\n", 337 __func__, writtenlen > 0 ? writtenlen : ret); 338 unlock_page(pg); 339 put_page(pg); 340 return writtenlen > 0 ? writtenlen : ret; 341 } 342