1 /* 2 * OMFS (as used by RIO Karma) file operations. 3 * Copyright (C) 2005 Bob Copeland <me@bobcopeland.com> 4 * Released under GPL v2. 5 */ 6 7 #include <linux/module.h> 8 #include <linux/fs.h> 9 #include <linux/buffer_head.h> 10 #include <linux/mpage.h> 11 #include "omfs.h" 12 13 static u32 omfs_max_extents(struct omfs_sb_info *sbi, int offset) 14 { 15 return (sbi->s_sys_blocksize - offset - 16 sizeof(struct omfs_extent)) / 17 sizeof(struct omfs_extent_entry) + 1; 18 } 19 20 void omfs_make_empty_table(struct buffer_head *bh, int offset) 21 { 22 struct omfs_extent *oe = (struct omfs_extent *) &bh->b_data[offset]; 23 24 oe->e_next = ~cpu_to_be64(0ULL); 25 oe->e_extent_count = cpu_to_be32(1), 26 oe->e_fill = cpu_to_be32(0x22), 27 oe->e_entry.e_cluster = ~cpu_to_be64(0ULL); 28 oe->e_entry.e_blocks = ~cpu_to_be64(0ULL); 29 } 30 31 int omfs_shrink_inode(struct inode *inode) 32 { 33 struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb); 34 struct omfs_extent *oe; 35 struct omfs_extent_entry *entry; 36 struct buffer_head *bh; 37 u64 next, last; 38 u32 extent_count; 39 u32 max_extents; 40 int ret; 41 42 /* traverse extent table, freeing each entry that is greater 43 * than inode->i_size; 44 */ 45 next = inode->i_ino; 46 47 /* only support truncate -> 0 for now */ 48 ret = -EIO; 49 if (inode->i_size != 0) 50 goto out; 51 52 bh = omfs_bread(inode->i_sb, next); 53 if (!bh) 54 goto out; 55 56 oe = (struct omfs_extent *)(&bh->b_data[OMFS_EXTENT_START]); 57 max_extents = omfs_max_extents(sbi, OMFS_EXTENT_START); 58 59 for (;;) { 60 61 if (omfs_is_bad(sbi, (struct omfs_header *) bh->b_data, next)) 62 goto out_brelse; 63 64 extent_count = be32_to_cpu(oe->e_extent_count); 65 66 if (extent_count > max_extents) 67 goto out_brelse; 68 69 last = next; 70 next = be64_to_cpu(oe->e_next); 71 entry = &oe->e_entry; 72 73 /* ignore last entry as it is the terminator */ 74 for (; extent_count > 1; extent_count--) { 75 u64 start, count; 76 start = be64_to_cpu(entry->e_cluster); 77 count = be64_to_cpu(entry->e_blocks); 78 79 omfs_clear_range(inode->i_sb, start, (int) count); 80 entry++; 81 } 82 omfs_make_empty_table(bh, (char *) oe - bh->b_data); 83 mark_buffer_dirty(bh); 84 brelse(bh); 85 86 if (last != inode->i_ino) 87 omfs_clear_range(inode->i_sb, last, sbi->s_mirrors); 88 89 if (next == ~0) 90 break; 91 92 bh = omfs_bread(inode->i_sb, next); 93 if (!bh) 94 goto out; 95 oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]); 96 max_extents = omfs_max_extents(sbi, OMFS_EXTENT_CONT); 97 } 98 ret = 0; 99 out: 100 return ret; 101 out_brelse: 102 brelse(bh); 103 return ret; 104 } 105 106 static void omfs_truncate(struct inode *inode) 107 { 108 omfs_shrink_inode(inode); 109 mark_inode_dirty(inode); 110 } 111 112 /* 113 * Add new blocks to the current extent, or create new entries/continuations 114 * as necessary. 115 */ 116 static int omfs_grow_extent(struct inode *inode, struct omfs_extent *oe, 117 u64 *ret_block) 118 { 119 struct omfs_extent_entry *terminator; 120 struct omfs_extent_entry *entry = &oe->e_entry; 121 struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb); 122 u32 extent_count = be32_to_cpu(oe->e_extent_count); 123 u64 new_block = 0; 124 u32 max_count; 125 int new_count; 126 int ret = 0; 127 128 /* reached the end of the extent table with no blocks mapped. 129 * there are three possibilities for adding: grow last extent, 130 * add a new extent to the current extent table, and add a 131 * continuation inode. in last two cases need an allocator for 132 * sbi->s_cluster_size 133 */ 134 135 /* TODO: handle holes */ 136 137 /* should always have a terminator */ 138 if (extent_count < 1) 139 return -EIO; 140 141 /* trivially grow current extent, if next block is not taken */ 142 terminator = entry + extent_count - 1; 143 if (extent_count > 1) { 144 entry = terminator-1; 145 new_block = be64_to_cpu(entry->e_cluster) + 146 be64_to_cpu(entry->e_blocks); 147 148 if (omfs_allocate_block(inode->i_sb, new_block)) { 149 entry->e_blocks = 150 cpu_to_be64(be64_to_cpu(entry->e_blocks) + 1); 151 terminator->e_blocks = ~(cpu_to_be64( 152 be64_to_cpu(~terminator->e_blocks) + 1)); 153 goto out; 154 } 155 } 156 max_count = omfs_max_extents(sbi, OMFS_EXTENT_START); 157 158 /* TODO: add a continuation block here */ 159 if (be32_to_cpu(oe->e_extent_count) > max_count-1) 160 return -EIO; 161 162 /* try to allocate a new cluster */ 163 ret = omfs_allocate_range(inode->i_sb, 1, sbi->s_clustersize, 164 &new_block, &new_count); 165 if (ret) 166 goto out_fail; 167 168 /* copy terminator down an entry */ 169 entry = terminator; 170 terminator++; 171 memcpy(terminator, entry, sizeof(struct omfs_extent_entry)); 172 173 entry->e_cluster = cpu_to_be64(new_block); 174 entry->e_blocks = cpu_to_be64((u64) new_count); 175 176 terminator->e_blocks = ~(cpu_to_be64( 177 be64_to_cpu(~terminator->e_blocks) + (u64) new_count)); 178 179 /* write in new entry */ 180 oe->e_extent_count = cpu_to_be32(1 + be32_to_cpu(oe->e_extent_count)); 181 182 out: 183 *ret_block = new_block; 184 out_fail: 185 return ret; 186 } 187 188 /* 189 * Scans across the directory table for a given file block number. 190 * If block not found, return 0. 191 */ 192 static sector_t find_block(struct inode *inode, struct omfs_extent_entry *ent, 193 sector_t block, int count, int *left) 194 { 195 /* count > 1 because of terminator */ 196 sector_t searched = 0; 197 for (; count > 1; count--) { 198 int numblocks = clus_to_blk(OMFS_SB(inode->i_sb), 199 be64_to_cpu(ent->e_blocks)); 200 201 if (block >= searched && 202 block < searched + numblocks) { 203 /* 204 * found it at cluster + (block - searched) 205 * numblocks - (block - searched) is remainder 206 */ 207 *left = numblocks - (block - searched); 208 return clus_to_blk(OMFS_SB(inode->i_sb), 209 be64_to_cpu(ent->e_cluster)) + 210 block - searched; 211 } 212 searched += numblocks; 213 ent++; 214 } 215 return 0; 216 } 217 218 static int omfs_get_block(struct inode *inode, sector_t block, 219 struct buffer_head *bh_result, int create) 220 { 221 struct buffer_head *bh; 222 sector_t next, offset; 223 int ret; 224 u64 uninitialized_var(new_block); 225 u32 max_extents; 226 int extent_count; 227 struct omfs_extent *oe; 228 struct omfs_extent_entry *entry; 229 struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb); 230 int max_blocks = bh_result->b_size >> inode->i_blkbits; 231 int remain; 232 233 ret = -EIO; 234 bh = omfs_bread(inode->i_sb, inode->i_ino); 235 if (!bh) 236 goto out; 237 238 oe = (struct omfs_extent *)(&bh->b_data[OMFS_EXTENT_START]); 239 max_extents = omfs_max_extents(sbi, OMFS_EXTENT_START); 240 next = inode->i_ino; 241 242 for (;;) { 243 244 if (omfs_is_bad(sbi, (struct omfs_header *) bh->b_data, next)) 245 goto out_brelse; 246 247 extent_count = be32_to_cpu(oe->e_extent_count); 248 next = be64_to_cpu(oe->e_next); 249 entry = &oe->e_entry; 250 251 if (extent_count > max_extents) 252 goto out_brelse; 253 254 offset = find_block(inode, entry, block, extent_count, &remain); 255 if (offset > 0) { 256 ret = 0; 257 map_bh(bh_result, inode->i_sb, offset); 258 if (remain > max_blocks) 259 remain = max_blocks; 260 bh_result->b_size = (remain << inode->i_blkbits); 261 goto out_brelse; 262 } 263 if (next == ~0) 264 break; 265 266 brelse(bh); 267 bh = omfs_bread(inode->i_sb, next); 268 if (!bh) 269 goto out; 270 oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]); 271 max_extents = omfs_max_extents(sbi, OMFS_EXTENT_CONT); 272 } 273 if (create) { 274 ret = omfs_grow_extent(inode, oe, &new_block); 275 if (ret == 0) { 276 mark_buffer_dirty(bh); 277 mark_inode_dirty(inode); 278 map_bh(bh_result, inode->i_sb, 279 clus_to_blk(sbi, new_block)); 280 } 281 } 282 out_brelse: 283 brelse(bh); 284 out: 285 return ret; 286 } 287 288 static int omfs_readpage(struct file *file, struct page *page) 289 { 290 return block_read_full_page(page, omfs_get_block); 291 } 292 293 static int omfs_readpages(struct file *file, struct address_space *mapping, 294 struct list_head *pages, unsigned nr_pages) 295 { 296 return mpage_readpages(mapping, pages, nr_pages, omfs_get_block); 297 } 298 299 static int omfs_writepage(struct page *page, struct writeback_control *wbc) 300 { 301 return block_write_full_page(page, omfs_get_block, wbc); 302 } 303 304 static int 305 omfs_writepages(struct address_space *mapping, struct writeback_control *wbc) 306 { 307 return mpage_writepages(mapping, wbc, omfs_get_block); 308 } 309 310 static int omfs_write_begin(struct file *file, struct address_space *mapping, 311 loff_t pos, unsigned len, unsigned flags, 312 struct page **pagep, void **fsdata) 313 { 314 int ret; 315 316 ret = block_write_begin(mapping, pos, len, flags, pagep, 317 omfs_get_block); 318 if (unlikely(ret)) { 319 loff_t isize = mapping->host->i_size; 320 if (pos + len > isize) 321 vmtruncate(mapping->host, isize); 322 } 323 324 return ret; 325 } 326 327 static sector_t omfs_bmap(struct address_space *mapping, sector_t block) 328 { 329 return generic_block_bmap(mapping, block, omfs_get_block); 330 } 331 332 const struct file_operations omfs_file_operations = { 333 .llseek = generic_file_llseek, 334 .read = do_sync_read, 335 .write = do_sync_write, 336 .aio_read = generic_file_aio_read, 337 .aio_write = generic_file_aio_write, 338 .mmap = generic_file_mmap, 339 .fsync = generic_file_fsync, 340 .splice_read = generic_file_splice_read, 341 }; 342 343 static int omfs_setattr(struct dentry *dentry, struct iattr *attr) 344 { 345 struct inode *inode = dentry->d_inode; 346 int error; 347 348 error = inode_change_ok(inode, attr); 349 if (error) 350 return error; 351 352 if ((attr->ia_valid & ATTR_SIZE) && 353 attr->ia_size != i_size_read(inode)) { 354 error = vmtruncate(inode, attr->ia_size); 355 if (error) 356 return error; 357 } 358 359 setattr_copy(inode, attr); 360 mark_inode_dirty(inode); 361 return 0; 362 } 363 364 const struct inode_operations omfs_file_inops = { 365 .setattr = omfs_setattr, 366 .truncate = omfs_truncate 367 }; 368 369 const struct address_space_operations omfs_aops = { 370 .readpage = omfs_readpage, 371 .readpages = omfs_readpages, 372 .writepage = omfs_writepage, 373 .writepages = omfs_writepages, 374 .write_begin = omfs_write_begin, 375 .write_end = generic_write_end, 376 .bmap = omfs_bmap, 377 }; 378 379