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 = generic_file_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 uint32_t pageofs = index << PAGE_SHIFT; 141 int ret = 0; 142 143 jffs2_dbg(1, "%s()\n", __func__); 144 145 if (pageofs > inode->i_size) { 146 /* Make new hole frag from old EOF to new page */ 147 struct jffs2_raw_inode ri; 148 struct jffs2_full_dnode *fn; 149 uint32_t alloc_len; 150 151 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n", 152 (unsigned int)inode->i_size, pageofs); 153 154 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len, 155 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE); 156 if (ret) 157 goto out_err; 158 159 mutex_lock(&f->sem); 160 memset(&ri, 0, sizeof(ri)); 161 162 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK); 163 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE); 164 ri.totlen = cpu_to_je32(sizeof(ri)); 165 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4)); 166 167 ri.ino = cpu_to_je32(f->inocache->ino); 168 ri.version = cpu_to_je32(++f->highest_version); 169 ri.mode = cpu_to_jemode(inode->i_mode); 170 ri.uid = cpu_to_je16(i_uid_read(inode)); 171 ri.gid = cpu_to_je16(i_gid_read(inode)); 172 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs)); 173 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW()); 174 ri.offset = cpu_to_je32(inode->i_size); 175 ri.dsize = cpu_to_je32(pageofs - inode->i_size); 176 ri.csize = cpu_to_je32(0); 177 ri.compr = JFFS2_COMPR_ZERO; 178 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8)); 179 ri.data_crc = cpu_to_je32(0); 180 181 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL); 182 183 if (IS_ERR(fn)) { 184 ret = PTR_ERR(fn); 185 jffs2_complete_reservation(c); 186 mutex_unlock(&f->sem); 187 goto out_err; 188 } 189 ret = jffs2_add_full_dnode_to_inode(c, f, fn); 190 if (f->metadata) { 191 jffs2_mark_node_obsolete(c, f->metadata->raw); 192 jffs2_free_full_dnode(f->metadata); 193 f->metadata = NULL; 194 } 195 if (ret) { 196 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", 197 ret); 198 jffs2_mark_node_obsolete(c, fn->raw); 199 jffs2_free_full_dnode(fn); 200 jffs2_complete_reservation(c); 201 mutex_unlock(&f->sem); 202 goto out_err; 203 } 204 jffs2_complete_reservation(c); 205 inode->i_size = pageofs; 206 mutex_unlock(&f->sem); 207 } 208 209 /* 210 * While getting a page and reading data in, lock c->alloc_sem until 211 * the page is Uptodate. Otherwise GC task may attempt to read the same 212 * page in read_cache_page(), which causes a deadlock. 213 */ 214 mutex_lock(&c->alloc_sem); 215 pg = grab_cache_page_write_begin(mapping, index); 216 if (!pg) { 217 ret = -ENOMEM; 218 goto release_sem; 219 } 220 *pagep = pg; 221 222 /* 223 * Read in the page if it wasn't already present. Cannot optimize away 224 * the whole page write case until jffs2_write_end can handle the 225 * case of a short-copy. 226 */ 227 if (!PageUptodate(pg)) { 228 mutex_lock(&f->sem); 229 ret = jffs2_do_readpage_nolock(inode, pg); 230 mutex_unlock(&f->sem); 231 if (ret) { 232 unlock_page(pg); 233 put_page(pg); 234 goto release_sem; 235 } 236 } 237 jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags); 238 239 release_sem: 240 mutex_unlock(&c->alloc_sem); 241 out_err: 242 return ret; 243 } 244 245 static int jffs2_write_end(struct file *filp, struct address_space *mapping, 246 loff_t pos, unsigned len, unsigned copied, 247 struct page *pg, void *fsdata) 248 { 249 /* Actually commit the write from the page cache page we're looking at. 250 * For now, we write the full page out each time. It sucks, but it's simple 251 */ 252 struct inode *inode = mapping->host; 253 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 254 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 255 struct jffs2_raw_inode *ri; 256 unsigned start = pos & (PAGE_SIZE - 1); 257 unsigned end = start + copied; 258 unsigned aligned_start = start & ~3; 259 int ret = 0; 260 uint32_t writtenlen = 0; 261 262 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n", 263 __func__, inode->i_ino, pg->index << PAGE_SHIFT, 264 start, end, pg->flags); 265 266 /* We need to avoid deadlock with page_cache_read() in 267 jffs2_garbage_collect_pass(). So the page must be 268 up to date to prevent page_cache_read() from trying 269 to re-lock it. */ 270 BUG_ON(!PageUptodate(pg)); 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 unlock_page(pg); 286 put_page(pg); 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 /* In 2.4, it was already kmapped by generic_file_write(). Doesn't 299 hurt to do it again. The alternative is ifdefs, which are ugly. */ 300 kmap(pg); 301 302 ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start, 303 (pg->index << PAGE_SHIFT) + aligned_start, 304 end - aligned_start, &writtenlen); 305 306 kunmap(pg); 307 308 if (ret) { 309 /* There was an error writing. */ 310 SetPageError(pg); 311 } 312 313 /* Adjust writtenlen for the padding we did, so we don't confuse our caller */ 314 writtenlen -= min(writtenlen, (start - aligned_start)); 315 316 if (writtenlen) { 317 if (inode->i_size < pos + writtenlen) { 318 inode->i_size = pos + writtenlen; 319 inode->i_blocks = (inode->i_size + 511) >> 9; 320 321 inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime)); 322 } 323 } 324 325 jffs2_free_raw_inode(ri); 326 327 if (start+writtenlen < end) { 328 /* generic_file_write has written more to the page cache than we've 329 actually written to the medium. Mark the page !Uptodate so that 330 it gets reread */ 331 jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n", 332 __func__); 333 SetPageError(pg); 334 ClearPageUptodate(pg); 335 } 336 337 jffs2_dbg(1, "%s() returning %d\n", 338 __func__, writtenlen > 0 ? writtenlen : ret); 339 unlock_page(pg); 340 put_page(pg); 341 return writtenlen > 0 ? writtenlen : ret; 342 } 343