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