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 SetPageUptodate(pg); 100 101 flush_dcache_page(pg); 102 kunmap(pg); 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->page); 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(struct file *filp, struct address_space *mapping, 127 loff_t pos, unsigned len, 128 struct page **pagep, void **fsdata) 129 { 130 struct page *pg; 131 struct inode *inode = mapping->host; 132 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 133 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 134 pgoff_t index = pos >> PAGE_SHIFT; 135 int ret = 0; 136 137 jffs2_dbg(1, "%s()\n", __func__); 138 139 if (pos > inode->i_size) { 140 /* Make new hole frag from old EOF to new position */ 141 struct jffs2_raw_inode ri; 142 struct jffs2_full_dnode *fn; 143 uint32_t alloc_len; 144 145 jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new position\n", 146 (unsigned int)inode->i_size, (uint32_t)pos); 147 148 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len, 149 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE); 150 if (ret) 151 goto out_err; 152 153 mutex_lock(&f->sem); 154 memset(&ri, 0, sizeof(ri)); 155 156 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK); 157 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE); 158 ri.totlen = cpu_to_je32(sizeof(ri)); 159 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4)); 160 161 ri.ino = cpu_to_je32(f->inocache->ino); 162 ri.version = cpu_to_je32(++f->highest_version); 163 ri.mode = cpu_to_jemode(inode->i_mode); 164 ri.uid = cpu_to_je16(i_uid_read(inode)); 165 ri.gid = cpu_to_je16(i_gid_read(inode)); 166 ri.isize = cpu_to_je32((uint32_t)pos); 167 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW()); 168 ri.offset = cpu_to_je32(inode->i_size); 169 ri.dsize = cpu_to_je32((uint32_t)pos - inode->i_size); 170 ri.csize = cpu_to_je32(0); 171 ri.compr = JFFS2_COMPR_ZERO; 172 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8)); 173 ri.data_crc = cpu_to_je32(0); 174 175 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL); 176 177 if (IS_ERR(fn)) { 178 ret = PTR_ERR(fn); 179 jffs2_complete_reservation(c); 180 mutex_unlock(&f->sem); 181 goto out_err; 182 } 183 ret = jffs2_add_full_dnode_to_inode(c, f, fn); 184 if (f->metadata) { 185 jffs2_mark_node_obsolete(c, f->metadata->raw); 186 jffs2_free_full_dnode(f->metadata); 187 f->metadata = NULL; 188 } 189 if (ret) { 190 jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", 191 ret); 192 jffs2_mark_node_obsolete(c, fn->raw); 193 jffs2_free_full_dnode(fn); 194 jffs2_complete_reservation(c); 195 mutex_unlock(&f->sem); 196 goto out_err; 197 } 198 jffs2_complete_reservation(c); 199 inode->i_size = pos; 200 mutex_unlock(&f->sem); 201 } 202 203 /* 204 * While getting a page and reading data in, lock c->alloc_sem until 205 * the page is Uptodate. Otherwise GC task may attempt to read the same 206 * page in read_cache_page(), which causes a deadlock. 207 */ 208 mutex_lock(&c->alloc_sem); 209 pg = grab_cache_page_write_begin(mapping, index); 210 if (!pg) { 211 ret = -ENOMEM; 212 goto release_sem; 213 } 214 *pagep = pg; 215 216 /* 217 * Read in the page if it wasn't already present. Cannot optimize away 218 * the whole page write case until jffs2_write_end can handle the 219 * case of a short-copy. 220 */ 221 if (!PageUptodate(pg)) { 222 mutex_lock(&f->sem); 223 ret = jffs2_do_readpage_nolock(inode, pg); 224 mutex_unlock(&f->sem); 225 if (ret) { 226 unlock_page(pg); 227 put_page(pg); 228 goto release_sem; 229 } 230 } 231 jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags); 232 233 release_sem: 234 mutex_unlock(&c->alloc_sem); 235 out_err: 236 return ret; 237 } 238 239 static int jffs2_write_end(struct file *filp, struct address_space *mapping, 240 loff_t pos, unsigned len, unsigned copied, 241 struct page *pg, void *fsdata) 242 { 243 /* Actually commit the write from the page cache page we're looking at. 244 * For now, we write the full page out each time. It sucks, but it's simple 245 */ 246 struct inode *inode = mapping->host; 247 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 248 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 249 struct jffs2_raw_inode *ri; 250 unsigned start = pos & (PAGE_SIZE - 1); 251 unsigned end = start + copied; 252 unsigned aligned_start = start & ~3; 253 int ret = 0; 254 uint32_t writtenlen = 0; 255 256 jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n", 257 __func__, inode->i_ino, pg->index << PAGE_SHIFT, 258 start, end, pg->flags); 259 260 /* We need to avoid deadlock with page_cache_read() in 261 jffs2_garbage_collect_pass(). So the page must be 262 up to date to prevent page_cache_read() from trying 263 to re-lock it. */ 264 BUG_ON(!PageUptodate(pg)); 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 unlock_page(pg); 280 put_page(pg); 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 /* In 2.4, it was already kmapped by generic_file_write(). Doesn't 293 hurt to do it again. The alternative is ifdefs, which are ugly. */ 294 kmap(pg); 295 296 ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start, 297 (pg->index << PAGE_SHIFT) + aligned_start, 298 end - aligned_start, &writtenlen); 299 300 kunmap(pg); 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 ClearPageUptodate(pg); 327 } 328 329 jffs2_dbg(1, "%s() returning %d\n", 330 __func__, writtenlen > 0 ? writtenlen : ret); 331 unlock_page(pg); 332 put_page(pg); 333 return writtenlen > 0 ? writtenlen : ret; 334 } 335