1 /* 2 * JFFS2 -- Journalling Flash File System, Version 2. 3 * 4 * Copyright © 2001-2007 Red Hat, Inc. 5 * 6 * Created by David Woodhouse <dwmw2@infradead.org> 7 * 8 * For licensing information, see the file 'LICENCE' in this directory. 9 * 10 */ 11 12 #include <linux/kernel.h> 13 #include <linux/slab.h> 14 #include <linux/fs.h> 15 #include <linux/time.h> 16 #include <linux/pagemap.h> 17 #include <linux/highmem.h> 18 #include <linux/crc32.h> 19 #include <linux/jffs2.h> 20 #include "nodelist.h" 21 22 static int jffs2_write_end(struct file *filp, struct address_space *mapping, 23 loff_t pos, unsigned len, unsigned copied, 24 struct page *pg, void *fsdata); 25 static int jffs2_write_begin(struct file *filp, struct address_space *mapping, 26 loff_t pos, unsigned len, unsigned flags, 27 struct page **pagep, void **fsdata); 28 static int jffs2_readpage (struct file *filp, struct page *pg); 29 30 int jffs2_fsync(struct file *filp, struct dentry *dentry, int datasync) 31 { 32 struct inode *inode = dentry->d_inode; 33 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 34 35 /* Trigger GC to flush any pending writes for this inode */ 36 jffs2_flush_wbuf_gc(c, inode->i_ino); 37 38 return 0; 39 } 40 41 const struct file_operations jffs2_file_operations = 42 { 43 .llseek = generic_file_llseek, 44 .open = generic_file_open, 45 .read = do_sync_read, 46 .aio_read = generic_file_aio_read, 47 .write = do_sync_write, 48 .aio_write = generic_file_aio_write, 49 .unlocked_ioctl=jffs2_ioctl, 50 .mmap = generic_file_readonly_mmap, 51 .fsync = jffs2_fsync, 52 .splice_read = generic_file_splice_read, 53 }; 54 55 /* jffs2_file_inode_operations */ 56 57 const struct inode_operations jffs2_file_inode_operations = 58 { 59 .permission = jffs2_permission, 60 .setattr = jffs2_setattr, 61 .setxattr = jffs2_setxattr, 62 .getxattr = jffs2_getxattr, 63 .listxattr = jffs2_listxattr, 64 .removexattr = jffs2_removexattr 65 }; 66 67 const struct address_space_operations jffs2_file_address_operations = 68 { 69 .readpage = jffs2_readpage, 70 .write_begin = jffs2_write_begin, 71 .write_end = jffs2_write_end, 72 }; 73 74 static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg) 75 { 76 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 77 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 78 unsigned char *pg_buf; 79 int ret; 80 81 D2(printk(KERN_DEBUG "jffs2_do_readpage_nolock(): ino #%lu, page at offset 0x%lx\n", inode->i_ino, pg->index << PAGE_CACHE_SHIFT)); 82 83 BUG_ON(!PageLocked(pg)); 84 85 pg_buf = kmap(pg); 86 /* FIXME: Can kmap fail? */ 87 88 ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE); 89 90 if (ret) { 91 ClearPageUptodate(pg); 92 SetPageError(pg); 93 } else { 94 SetPageUptodate(pg); 95 ClearPageError(pg); 96 } 97 98 flush_dcache_page(pg); 99 kunmap(pg); 100 101 D2(printk(KERN_DEBUG "readpage finished\n")); 102 return 0; 103 } 104 105 int jffs2_do_readpage_unlock(struct inode *inode, struct page *pg) 106 { 107 int ret = jffs2_do_readpage_nolock(inode, pg); 108 unlock_page(pg); 109 return ret; 110 } 111 112 113 static int jffs2_readpage (struct file *filp, struct page *pg) 114 { 115 struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host); 116 int ret; 117 118 mutex_lock(&f->sem); 119 ret = jffs2_do_readpage_unlock(pg->mapping->host, pg); 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, unsigned flags, 126 struct page **pagep, void **fsdata) 127 { 128 struct page *pg; 129 struct inode *inode = mapping->host; 130 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 131 pgoff_t index = pos >> PAGE_CACHE_SHIFT; 132 uint32_t pageofs = index << PAGE_CACHE_SHIFT; 133 int ret = 0; 134 135 pg = grab_cache_page_write_begin(mapping, index, flags); 136 if (!pg) 137 return -ENOMEM; 138 *pagep = pg; 139 140 D1(printk(KERN_DEBUG "jffs2_write_begin()\n")); 141 142 if (pageofs > inode->i_size) { 143 /* Make new hole frag from old EOF to new page */ 144 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 145 struct jffs2_raw_inode ri; 146 struct jffs2_full_dnode *fn; 147 uint32_t alloc_len; 148 149 D1(printk(KERN_DEBUG "Writing new hole frag 0x%x-0x%x between current EOF and new page\n", 150 (unsigned int)inode->i_size, pageofs)); 151 152 ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len, 153 ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE); 154 if (ret) 155 goto out_page; 156 157 mutex_lock(&f->sem); 158 memset(&ri, 0, sizeof(ri)); 159 160 ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK); 161 ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE); 162 ri.totlen = cpu_to_je32(sizeof(ri)); 163 ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4)); 164 165 ri.ino = cpu_to_je32(f->inocache->ino); 166 ri.version = cpu_to_je32(++f->highest_version); 167 ri.mode = cpu_to_jemode(inode->i_mode); 168 ri.uid = cpu_to_je16(inode->i_uid); 169 ri.gid = cpu_to_je16(inode->i_gid); 170 ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs)); 171 ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds()); 172 ri.offset = cpu_to_je32(inode->i_size); 173 ri.dsize = cpu_to_je32(pageofs - inode->i_size); 174 ri.csize = cpu_to_je32(0); 175 ri.compr = JFFS2_COMPR_ZERO; 176 ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8)); 177 ri.data_crc = cpu_to_je32(0); 178 179 fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL); 180 181 if (IS_ERR(fn)) { 182 ret = PTR_ERR(fn); 183 jffs2_complete_reservation(c); 184 mutex_unlock(&f->sem); 185 goto out_page; 186 } 187 ret = jffs2_add_full_dnode_to_inode(c, f, fn); 188 if (f->metadata) { 189 jffs2_mark_node_obsolete(c, f->metadata->raw); 190 jffs2_free_full_dnode(f->metadata); 191 f->metadata = NULL; 192 } 193 if (ret) { 194 D1(printk(KERN_DEBUG "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n", ret)); 195 jffs2_mark_node_obsolete(c, fn->raw); 196 jffs2_free_full_dnode(fn); 197 jffs2_complete_reservation(c); 198 mutex_unlock(&f->sem); 199 goto out_page; 200 } 201 jffs2_complete_reservation(c); 202 inode->i_size = pageofs; 203 mutex_unlock(&f->sem); 204 } 205 206 /* 207 * Read in the page if it wasn't already present. Cannot optimize away 208 * the whole page write case until jffs2_write_end can handle the 209 * case of a short-copy. 210 */ 211 if (!PageUptodate(pg)) { 212 mutex_lock(&f->sem); 213 ret = jffs2_do_readpage_nolock(inode, pg); 214 mutex_unlock(&f->sem); 215 if (ret) 216 goto out_page; 217 } 218 D1(printk(KERN_DEBUG "end write_begin(). pg->flags %lx\n", pg->flags)); 219 return ret; 220 221 out_page: 222 unlock_page(pg); 223 page_cache_release(pg); 224 return ret; 225 } 226 227 static int jffs2_write_end(struct file *filp, struct address_space *mapping, 228 loff_t pos, unsigned len, unsigned copied, 229 struct page *pg, void *fsdata) 230 { 231 /* Actually commit the write from the page cache page we're looking at. 232 * For now, we write the full page out each time. It sucks, but it's simple 233 */ 234 struct inode *inode = mapping->host; 235 struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); 236 struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb); 237 struct jffs2_raw_inode *ri; 238 unsigned start = pos & (PAGE_CACHE_SIZE - 1); 239 unsigned end = start + copied; 240 unsigned aligned_start = start & ~3; 241 int ret = 0; 242 uint32_t writtenlen = 0; 243 244 D1(printk(KERN_DEBUG "jffs2_write_end(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n", 245 inode->i_ino, pg->index << PAGE_CACHE_SHIFT, start, end, pg->flags)); 246 247 /* We need to avoid deadlock with page_cache_read() in 248 jffs2_garbage_collect_pass(). So the page must be 249 up to date to prevent page_cache_read() from trying 250 to re-lock it. */ 251 BUG_ON(!PageUptodate(pg)); 252 253 if (end == PAGE_CACHE_SIZE) { 254 /* When writing out the end of a page, write out the 255 _whole_ page. This helps to reduce the number of 256 nodes in files which have many short writes, like 257 syslog files. */ 258 aligned_start = 0; 259 } 260 261 ri = jffs2_alloc_raw_inode(); 262 263 if (!ri) { 264 D1(printk(KERN_DEBUG "jffs2_write_end(): Allocation of raw inode failed\n")); 265 unlock_page(pg); 266 page_cache_release(pg); 267 return -ENOMEM; 268 } 269 270 /* Set the fields that the generic jffs2_write_inode_range() code can't find */ 271 ri->ino = cpu_to_je32(inode->i_ino); 272 ri->mode = cpu_to_jemode(inode->i_mode); 273 ri->uid = cpu_to_je16(inode->i_uid); 274 ri->gid = cpu_to_je16(inode->i_gid); 275 ri->isize = cpu_to_je32((uint32_t)inode->i_size); 276 ri->atime = ri->ctime = ri->mtime = cpu_to_je32(get_seconds()); 277 278 /* In 2.4, it was already kmapped by generic_file_write(). Doesn't 279 hurt to do it again. The alternative is ifdefs, which are ugly. */ 280 kmap(pg); 281 282 ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start, 283 (pg->index << PAGE_CACHE_SHIFT) + aligned_start, 284 end - aligned_start, &writtenlen); 285 286 kunmap(pg); 287 288 if (ret) { 289 /* There was an error writing. */ 290 SetPageError(pg); 291 } 292 293 /* Adjust writtenlen for the padding we did, so we don't confuse our caller */ 294 writtenlen -= min(writtenlen, (start - aligned_start)); 295 296 if (writtenlen) { 297 if (inode->i_size < pos + writtenlen) { 298 inode->i_size = pos + writtenlen; 299 inode->i_blocks = (inode->i_size + 511) >> 9; 300 301 inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime)); 302 } 303 } 304 305 jffs2_free_raw_inode(ri); 306 307 if (start+writtenlen < end) { 308 /* generic_file_write has written more to the page cache than we've 309 actually written to the medium. Mark the page !Uptodate so that 310 it gets reread */ 311 D1(printk(KERN_DEBUG "jffs2_write_end(): Not all bytes written. Marking page !uptodate\n")); 312 SetPageError(pg); 313 ClearPageUptodate(pg); 314 } 315 316 D1(printk(KERN_DEBUG "jffs2_write_end() returning %d\n", 317 writtenlen > 0 ? writtenlen : ret)); 318 unlock_page(pg); 319 page_cache_release(pg); 320 return writtenlen > 0 ? writtenlen : ret; 321 } 322