swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 1 | #include <alloc.h> |
swissChili | 4418ca5 | 2021-06-14 17:36:00 -0700 | [diff] [blame] | 2 | #include <dri/ata_pio/ata_pio.h> |
swissChili | e5adca5 | 2021-06-16 21:00:31 -0700 | [diff] [blame] | 3 | #include <dri/fs/ext2/ext2.h> |
swissChili | a664e72 | 2021-07-27 17:47:55 -0700 | [diff] [blame] | 4 | #include <dri/fs/ext2/ext2_vfs.h> |
| 5 | #include <vfs.h> |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 6 | #include <io.h> |
swissChili | ef829f3 | 2021-06-13 20:00:54 -0700 | [diff] [blame] | 7 | #include <kint.h> |
swissChili | 4418ca5 | 2021-06-14 17:36:00 -0700 | [diff] [blame] | 8 | #include <log.h> |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 9 | |
swissChili | d98781b | 2021-07-25 21:04:17 -0700 | [diff] [blame] | 10 | #define F(f,t) [EXT2_S_##f >> 12] = EXT2_FT_##t, |
| 11 | const uchar ext2_s_to_ft[] = |
| 12 | { |
| 13 | 0, |
| 14 | F(IFSOCK, SOCK) |
| 15 | F(IFLINK, SYMLINK) |
| 16 | F(IFREG, REGULAR_FILE) |
| 17 | F(IFBLK, BLKDEV) |
| 18 | F(IFDIR, DIR) |
| 19 | F(IFCHR, CHRDEV) |
| 20 | F(IFIFO, FIFO) |
| 21 | }; |
| 22 | #undef F |
| 23 | |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 24 | void ext2_read_block(struct ext2_superblock *sb, void *buffer, uint block) |
| 25 | { |
| 26 | uint block_size = ext2_block_size(sb) / 512; |
| 27 | uint block_start = block_size * block; |
| 28 | |
| 29 | ata_pio_read_sectors(buffer, block_start, block_size); |
| 30 | } |
swissChili | 4418ca5 | 2021-06-14 17:36:00 -0700 | [diff] [blame] | 31 | |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 32 | void ext2_write_block(struct ext2_superblock *sb, void *buffer, uint block) |
| 33 | { |
| 34 | uint block_size = ext2_block_size(sb) / 512; |
| 35 | uint block_start = block_size * block; |
| 36 | |
| 37 | ata_pio_write_sectors(block_start, block_size, buffer); |
| 38 | } |
| 39 | |
swissChili | 4418ca5 | 2021-06-14 17:36:00 -0700 | [diff] [blame] | 40 | struct ext2_superblock ext2_read_superblock() |
| 41 | { |
| 42 | uchar buffer[512 * 2]; |
| 43 | ata_pio_read_sectors(buffer, 2, 2); |
| 44 | |
| 45 | struct ext2_superblock *sb = (void *)(buffer); |
| 46 | return *sb; |
| 47 | } |
swissChili | ef829f3 | 2021-06-13 20:00:54 -0700 | [diff] [blame] | 48 | |
swissChili | e5adca5 | 2021-06-16 21:00:31 -0700 | [diff] [blame] | 49 | uint ext2_num_block_groups(struct ext2_superblock *sb) |
| 50 | { |
| 51 | // This is a mildly janky way of rounding up |
swissChili | 36ed5d7 | 2021-07-23 14:56:36 -0700 | [diff] [blame] | 52 | uint a = IDIV_CEIL(sb->total_blocks, sb->blocks_per_block_group); |
| 53 | uint b = IDIV_CEIL(sb->total_inodes, sb->inodes_per_block_group); |
swissChili | e5adca5 | 2021-06-16 21:00:31 -0700 | [diff] [blame] | 54 | |
| 55 | if (a == b) |
| 56 | { |
| 57 | return a; |
| 58 | } |
| 59 | else |
| 60 | { |
| 61 | kprintf(ERROR "EXT2 cannot find number of block groups, %d and %d " |
| 62 | "should equal.\n", |
| 63 | a, b); |
| 64 | kpanic("Corrupted filesystem"); |
| 65 | } |
| 66 | } |
| 67 | |
swissChili | 480f176 | 2021-07-26 22:17:34 -0700 | [diff] [blame] | 68 | void ext2_write_bgd(struct ext2_superblock *sb, uint block_group, |
| 69 | struct ext2_block_group_descriptor *d) |
| 70 | { |
| 71 | ext2_load_or_write_bgd(sb, block_group, d, true); |
| 72 | } |
| 73 | |
| 74 | struct ext2_block_group_descriptor ext2_load_bgd( |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 75 | struct ext2_superblock *sb, uint block_group) |
swissChili | e5adca5 | 2021-06-16 21:00:31 -0700 | [diff] [blame] | 76 | { |
swissChili | 480f176 | 2021-07-26 22:17:34 -0700 | [diff] [blame] | 77 | struct ext2_block_group_descriptor bgd; |
| 78 | ext2_load_or_write_bgd(sb, block_group, &bgd, false); |
| 79 | |
| 80 | return bgd; |
| 81 | } |
| 82 | |
| 83 | void ext2_load_or_write_bgd(struct ext2_superblock *sb, |
| 84 | uint block_group, |
| 85 | struct ext2_block_group_descriptor *d, |
| 86 | bool set) |
| 87 | { |
swissChili | e5adca5 | 2021-06-16 21:00:31 -0700 | [diff] [blame] | 88 | /** |
| 89 | * The BGDT (not to be confused with the GDT) is located the block after the |
| 90 | * superblock. On any block size EXCEPT 1024 (the minimum, remember that the |
| 91 | * block size is specified by X where 1024 << X is the real size) this is |
| 92 | * the second block (0-indexed, so 1). On 1024 this is the third block. |
| 93 | */ |
| 94 | uint bgdt_block = 1; |
| 95 | uint block_size = ext2_block_size(sb); |
| 96 | |
| 97 | if (block_size == 1024) |
| 98 | bgdt_block = 2; |
| 99 | |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 100 | const uint bgd_size = sizeof(struct ext2_block_group_descriptor); |
| 101 | |
| 102 | // Disk page that the BGD is on relative to the initial FILE SYSTEM block |
| 103 | uint hd_page = block_group / (512 / bgd_size); |
| 104 | // The offset from the beginning of that page the BGD is at |
| 105 | uint bgd_offset = block_group % (512 / bgd_size); |
| 106 | |
| 107 | struct ext2_block_group_descriptor descriptors[512 / bgd_size]; |
| 108 | kassert(sizeof(descriptors) == 512, "Wrong BGD size"); |
| 109 | |
| 110 | uint lba = (block_size / 512) * bgdt_block + hd_page; |
| 111 | |
swissChili | 480f176 | 2021-07-26 22:17:34 -0700 | [diff] [blame] | 112 | ata_pio_read_sectors(descriptors, lba, 1); |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 113 | |
swissChili | 480f176 | 2021-07-26 22:17:34 -0700 | [diff] [blame] | 114 | if (set) |
| 115 | { |
| 116 | descriptors[bgd_offset] = *d; |
| 117 | ata_pio_write_sectors(lba, 1, (ushort *)descriptors); |
| 118 | } |
| 119 | else |
| 120 | { |
| 121 | *d = descriptors[bgd_offset]; |
| 122 | } |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 123 | } |
| 124 | |
swissChili | d98781b | 2021-07-25 21:04:17 -0700 | [diff] [blame] | 125 | static bool print_entry(uint inode, const char *name, uint l, void *sb) |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 126 | { |
| 127 | kprintf("%d\t %s\n", inode, name); |
swissChili | cbd4363 | 2021-07-17 16:19:44 -0700 | [diff] [blame] | 128 | |
swissChili | d98781b | 2021-07-25 21:04:17 -0700 | [diff] [blame] | 129 | return true; |
swissChili | 36ed5d7 | 2021-07-23 14:56:36 -0700 | [diff] [blame] | 130 | |
swissChili | cbd4363 | 2021-07-17 16:19:44 -0700 | [diff] [blame] | 131 | struct ext2_inode in; |
| 132 | |
| 133 | if (ext2_find_inode(sb, inode, &in)) |
| 134 | { |
| 135 | if ((in.mode & EXT2_F_TYPE) == EXT2_S_IFREG) |
| 136 | { |
| 137 | char buffer[65]; |
| 138 | uint read = ext2_read_inode(sb, &in, buffer, 64); |
| 139 | buffer[read] = 0; |
| 140 | |
| 141 | kprintf("contents: %d\n'%s'\n", read, buffer); |
| 142 | } |
| 143 | } |
| 144 | |
swissChili | d98781b | 2021-07-25 21:04:17 -0700 | [diff] [blame] | 145 | return true; |
swissChili | e5adca5 | 2021-06-16 21:00:31 -0700 | [diff] [blame] | 146 | } |
| 147 | |
swissChili | ef829f3 | 2021-06-13 20:00:54 -0700 | [diff] [blame] | 148 | void ext2_mount(struct fs_node *where) |
| 149 | { |
swissChili | d98781b | 2021-07-25 21:04:17 -0700 | [diff] [blame] | 150 | |
swissChili | a664e72 | 2021-07-27 17:47:55 -0700 | [diff] [blame] | 151 | struct ext2_superblock *sb = malloc(sizeof(struct ext2_superblock)); |
| 152 | *sb = ext2_read_superblock(); |
swissChili | 4418ca5 | 2021-06-14 17:36:00 -0700 | [diff] [blame] | 153 | |
swissChili | a664e72 | 2021-07-27 17:47:55 -0700 | [diff] [blame] | 154 | struct fs_node *ext2_root = ext2_inode2vfs(sb, 2, "/", 1); |
| 155 | uint err; |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 156 | |
swissChili | a664e72 | 2021-07-27 17:47:55 -0700 | [diff] [blame] | 157 | if ((err = fs_mount(where, ext2_root))) |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 158 | { |
swissChili | a664e72 | 2021-07-27 17:47:55 -0700 | [diff] [blame] | 159 | kprintf(WARN "Failed to mount EXT2: error %d\n", err); |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 160 | } |
swissChili | ef829f3 | 2021-06-13 20:00:54 -0700 | [diff] [blame] | 161 | } |
swissChili | 9bd74de | 2021-06-15 20:30:48 -0700 | [diff] [blame] | 162 | |
| 163 | bool ext2_valid_filesystem() |
| 164 | { |
| 165 | struct ext2_superblock sb = ext2_read_superblock(); |
| 166 | |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 167 | kprintf(DEBUG "superblock signature is %d (0x%x)\n", sb.signature, |
| 168 | sb.signature); |
swissChili | 276b8cf | 2021-07-16 13:24:42 -0700 | [diff] [blame] | 169 | |
swissChili | 9bd74de | 2021-06-15 20:30:48 -0700 | [diff] [blame] | 170 | return sb.signature == EXT2_SIGNATURE; |
swissChili | e5adca5 | 2021-06-16 21:00:31 -0700 | [diff] [blame] | 171 | } |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 172 | |
| 173 | void ext2_write_superblock(struct ext2_superblock *sb) |
| 174 | { |
| 175 | ushort *wp = (ushort *)sb; |
| 176 | |
| 177 | ata_pio_write_sectors(2, 2, wp); |
| 178 | } |
| 179 | |
| 180 | void ext2_corrupt_superblock_for_fun() |
| 181 | { |
| 182 | struct ext2_superblock sb = ext2_read_superblock(); |
| 183 | sb.signature = 0xDEAD; |
| 184 | ext2_write_superblock(&sb); |
| 185 | } |
| 186 | |
swissChili | d98781b | 2021-07-25 21:04:17 -0700 | [diff] [blame] | 187 | bool ext2_get_or_set_inode(struct ext2_superblock *sb, uint number, |
| 188 | struct ext2_inode *inode, bool set) |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 189 | { |
| 190 | if (number == 0) |
| 191 | return false; |
| 192 | |
| 193 | uint block_group = (number - 1) / sb->inodes_per_block_group; |
| 194 | uint local_index = (number - 1) % sb->inodes_per_block_group; |
| 195 | |
| 196 | // Load this from the block group descriptor table |
| 197 | struct ext2_block_group_descriptor descriptor = |
swissChili | 480f176 | 2021-07-26 22:17:34 -0700 | [diff] [blame] | 198 | ext2_load_bgd(sb, block_group); |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 199 | |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 200 | // We need to figure out what FS block the inode is on, we know how many |
| 201 | // inodes there are total in this BGD and the number per page, so this is |
| 202 | // simple. |
| 203 | |
| 204 | const uint block_size = ext2_block_size(sb); |
| 205 | |
swissChili | d98781b | 2021-07-25 21:04:17 -0700 | [diff] [blame] | 206 | const uint inodes_per_block = |
| 207 | block_size / sizeof(struct ext2_inode); |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 208 | |
| 209 | uint inode_block = local_index / inodes_per_block; |
| 210 | uint inode_index = local_index % inodes_per_block; |
| 211 | |
| 212 | struct ext2_inode inodes[block_size / sizeof(struct ext2_inode)]; |
| 213 | |
swissChili | d98781b | 2021-07-25 21:04:17 -0700 | [diff] [blame] | 214 | const uint fs_block = descriptor.inode_table_start_block + |
| 215 | inode_block; |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 216 | |
swissChili | d98781b | 2021-07-25 21:04:17 -0700 | [diff] [blame] | 217 | ext2_read_block(sb, inodes, fs_block); |
| 218 | |
| 219 | if (set) |
| 220 | { |
| 221 | inodes[inode_index] = *inode; |
| 222 | |
| 223 | ext2_write_block(sb, inodes, fs_block); |
| 224 | } |
| 225 | else |
| 226 | { |
| 227 | *inode = inodes[inode_index]; |
| 228 | } |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 229 | |
| 230 | return true; |
| 231 | } |
| 232 | |
swissChili | d98781b | 2021-07-25 21:04:17 -0700 | [diff] [blame] | 233 | bool ext2_find_inode(struct ext2_superblock *sb, uint number, |
| 234 | struct ext2_inode *inode) |
| 235 | { |
| 236 | return ext2_get_or_set_inode(sb, number, inode, false); |
| 237 | } |
| 238 | |
| 239 | bool ext2_set_inode(struct ext2_superblock *sb, uint number, |
| 240 | struct ext2_inode *inode) |
| 241 | { |
| 242 | return ext2_get_or_set_inode(sb, number, inode, true); |
| 243 | } |
| 244 | |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 245 | bool ext2_dir_ls(struct ext2_superblock *sb, struct ext2_inode *dir, |
swissChili | d98781b | 2021-07-25 21:04:17 -0700 | [diff] [blame] | 246 | bool (*cb)(uint inode, const char *name, uint name_len, |
| 247 | void *data), |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 248 | void *data) |
| 249 | { |
| 250 | if ((dir->mode & 0xf000) != EXT2_S_IFDIR) |
| 251 | return false; |
| 252 | |
swissChili | d98781b | 2021-07-25 21:04:17 -0700 | [diff] [blame] | 253 | for (uint i = 0; i < dir->num_blocks; i++) |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 254 | { |
| 255 | uchar buffer[ext2_block_size(sb)]; |
| 256 | ext2_read_inode_block(sb, dir, buffer, i); |
| 257 | |
| 258 | struct ext2_dirent *ent = (void *)buffer; |
| 259 | |
| 260 | // While there are files in this block |
swissChili | cbd4363 | 2021-07-17 16:19:44 -0700 | [diff] [blame] | 261 | while ((uint)ent < (uint)(buffer + ext2_block_size(sb))) |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 262 | { |
| 263 | if (ent->inode == 0) |
| 264 | return true; |
| 265 | |
| 266 | if (cb) |
| 267 | { |
swissChili | 36ed5d7 | 2021-07-23 14:56:36 -0700 | [diff] [blame] | 268 | char name[256]; |
| 269 | uint name_len = MIN(ent->name_len, 255); |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 270 | |
swissChili | 36ed5d7 | 2021-07-23 14:56:36 -0700 | [diff] [blame] | 271 | memcpy(name, ent->name, name_len); |
| 272 | name[name_len] = '\0'; |
swissChili | cbd4363 | 2021-07-17 16:19:44 -0700 | [diff] [blame] | 273 | |
swissChili | d98781b | 2021-07-25 21:04:17 -0700 | [diff] [blame] | 274 | if (!cb(ent->inode, name, name_len, data)) |
| 275 | return true; |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 276 | } |
| 277 | |
| 278 | ent = (void *)(((uint)(void *)ent) + ent->rec_len); |
| 279 | } |
| 280 | // We ran out of files in this block, continue to the next one. This |
| 281 | // works because files cannot span blocks |
| 282 | } |
| 283 | |
| 284 | return true; |
| 285 | } |
| 286 | |
swissChili | 36ed5d7 | 2021-07-23 14:56:36 -0700 | [diff] [blame] | 287 | static void ext2_show_dirent(struct ext2_dirent *ent) |
| 288 | { |
| 289 | char name[ent->name_len + 1]; |
| 290 | memcpy(name, ent->name, ent->name_len); |
| 291 | name[ent->name_len] = '\0'; |
| 292 | |
| 293 | kprintf(DEBUG "<ent ft=%p, i=%d, s=%s, l=%d>\n", ent->file_type, ent->inode, |
| 294 | ent->name, ent->rec_len); |
| 295 | } |
| 296 | |
swissChili | d98781b | 2021-07-25 21:04:17 -0700 | [diff] [blame] | 297 | bool ext2_hard_link(struct ext2_superblock *sb, struct ext2_inode *dir, |
| 298 | char *name, uint name_len, uint inode) |
| 299 | { |
| 300 | struct ext2_inode in; |
| 301 | |
| 302 | if (!ext2_dir_contains(sb, dir, name, name_len) && |
| 303 | ext2_find_inode(sb, inode, &in)) |
| 304 | { |
| 305 | if ((dir->mode & 0xf000) != EXT2_S_IFDIR) |
| 306 | { |
| 307 | return false; |
| 308 | } |
| 309 | |
| 310 | // Increment the reference count to this inode |
| 311 | in.links_count++; |
| 312 | ext2_set_inode(sb, inode, &in); |
| 313 | |
| 314 | // Insert it into the directory |
| 315 | uchar type = EXT2_S_TO_FT(in.mode); |
| 316 | ext2_insert_into_dir(sb, dir, name, name_len, inode, type); |
| 317 | |
| 318 | return true; |
| 319 | } |
| 320 | else |
| 321 | { |
| 322 | return false; |
| 323 | } |
| 324 | } |
| 325 | |
swissChili | 36ed5d7 | 2021-07-23 14:56:36 -0700 | [diff] [blame] | 326 | void ext2_insert_into_dir(struct ext2_superblock *sb, struct ext2_inode *dir, |
| 327 | char *name, uint name_len, uint inode, uchar type) |
| 328 | { |
| 329 | name_len = MIN(name_len, 255); |
| 330 | const uint min_size = PAD(name_len + sizeof(struct ext2_dirent)); |
| 331 | const uint block_size = ext2_block_size(sb); |
| 332 | |
| 333 | if ((dir->mode & 0xf000) != EXT2_S_IFDIR) |
| 334 | return; |
| 335 | |
| 336 | uchar buffer[block_size]; |
| 337 | uint i; // block # |
| 338 | |
| 339 | for (i = 0; i < dir->num_blocks; i++) |
| 340 | { |
| 341 | ext2_read_inode_block(sb, dir, buffer, i); |
| 342 | |
| 343 | struct ext2_dirent *ent = (void *)buffer; |
| 344 | |
| 345 | // While there are files in this block |
| 346 | while ((uint)ent < (uint)(buffer + block_size)) |
| 347 | { |
| 348 | // kprintf(" %d@%db,%d-%d", ent->inode, i, (uint)ent - (uint)buffer, |
| 349 | // ent->rec_len); |
| 350 | if (ent->inode == 0) |
| 351 | { |
| 352 | // This is the last item, just insert it at the end |
| 353 | // TODO: check this actually fits! |
| 354 | // TODO: if we are in a new block, actually create it! |
| 355 | |
| 356 | ent->rec_len = min_size; |
| 357 | ent->name_len = name_len; |
| 358 | memcpy(ent->name, name, name_len); |
| 359 | ent->inode = inode; |
| 360 | ent->file_type = type; |
| 361 | |
| 362 | kprintf(DEBUG |
| 363 | "Inserted into dir (appending) at block=%d, b=%p \n", |
| 364 | i, (uint)ent - (uint)buffer); |
| 365 | |
| 366 | goto finish; |
| 367 | } |
| 368 | |
| 369 | uint this_min_size = |
| 370 | PAD(ent->name_len + sizeof(struct ext2_dirent)); |
| 371 | uint available_size = ent->rec_len - this_min_size; |
| 372 | |
swissChili | d98781b | 2021-07-25 21:04:17 -0700 | [diff] [blame] | 373 | // kprintf(",%d=%d/%d", ent->name_len, this_min_size, |
| 374 | // available_size); |
swissChili | 36ed5d7 | 2021-07-23 14:56:36 -0700 | [diff] [blame] | 375 | |
| 376 | if (available_size >= min_size) |
| 377 | { |
| 378 | // We can fit this in here |
| 379 | struct ext2_dirent *inserting = |
| 380 | (void *)(((uint)(void *)ent) + this_min_size); |
| 381 | |
| 382 | ent->rec_len = this_min_size; |
| 383 | |
| 384 | inserting->rec_len = available_size; |
| 385 | inserting->name_len = name_len; |
| 386 | inserting->inode = inode; |
| 387 | inserting->file_type = type; |
| 388 | memcpy(inserting->name, name, name_len); |
| 389 | |
| 390 | kprintf(DEBUG |
| 391 | "Inserted into dir (splicing) at block=%d, b=%p \n", |
| 392 | i, (uint)inserting - (uint)buffer); |
| 393 | |
| 394 | // Done! |
| 395 | goto finish; |
| 396 | } |
| 397 | |
| 398 | ent = (void *)(((uint)(void *)ent) + ent->rec_len); |
| 399 | } |
| 400 | // We ran out of files in this block, continue to the next one. This |
| 401 | // works because files cannot span blocks |
| 402 | } |
| 403 | |
| 404 | kprintf("\n"); |
| 405 | |
| 406 | kprintf(WARN "Failed to insert!\n"); |
| 407 | |
| 408 | finish: |
| 409 | kprintf("\n"); |
| 410 | ext2_write_inode_block(sb, dir, buffer, i); |
| 411 | kprintf(DEBUG "[insert] writing inode block %d\n", i); |
| 412 | } |
| 413 | |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 414 | ssize_t ext2_read_inode(struct ext2_superblock *sb, struct ext2_inode *inode, |
| 415 | void *buffer, ssize_t size) |
swissChili | cbd4363 | 2021-07-17 16:19:44 -0700 | [diff] [blame] | 416 | { |
| 417 | const uint block_size = ext2_block_size(sb); |
| 418 | char transfer[block_size]; |
| 419 | |
swissChili | e4229a2 | 2023-01-01 15:59:53 -0500 | [diff] [blame] | 420 | uint fsize = MIN(inode->size, (uint)size); |
swissChili | cbd4363 | 2021-07-17 16:19:44 -0700 | [diff] [blame] | 421 | uint i; |
| 422 | |
| 423 | // Transfer full blocks straight to the output buffer |
| 424 | for (i = 0; i < fsize / block_size; i++) |
| 425 | { |
| 426 | ext2_read_inode_block(sb, inode, buffer + i * block_size, i); |
| 427 | } |
| 428 | |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 429 | // If we have part of a block left over read it here first, then transfer |
| 430 | // what we need |
swissChili | cbd4363 | 2021-07-17 16:19:44 -0700 | [diff] [blame] | 431 | if (i * block_size < fsize) |
| 432 | { |
| 433 | uint remainder = fsize % block_size; |
| 434 | |
| 435 | ext2_read_inode_block(sb, inode, transfer, i); |
| 436 | memcpy(buffer + i * block_size, transfer, remainder); |
| 437 | } |
| 438 | |
| 439 | return fsize; |
| 440 | } |
| 441 | |
swissChili | 36ed5d7 | 2021-07-23 14:56:36 -0700 | [diff] [blame] | 442 | static uint ext2_compute_absolute_block(struct ext2_superblock *sb, |
| 443 | struct ext2_inode *inode, uint block) |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 444 | { |
| 445 | if (block >= 12) |
| 446 | { |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 447 | kprintf(ERROR |
| 448 | "Sorry, EXT2 can only access the first 12 (direct) blocks " |
| 449 | "of an inode for now. Indirect look-up will be added later\n"); |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 450 | kpanic("Invalid inode block"); |
| 451 | } |
| 452 | |
swissChili | 36ed5d7 | 2021-07-23 14:56:36 -0700 | [diff] [blame] | 453 | return block; |
| 454 | } |
| 455 | |
| 456 | bool ext2_read_inode_block(struct ext2_superblock *sb, struct ext2_inode *inode, |
| 457 | void *buffer, uint block) |
| 458 | { |
| 459 | block = ext2_compute_absolute_block(sb, inode, block); |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 460 | uint block_address = inode->blocks[block]; |
| 461 | |
| 462 | ext2_read_block(sb, buffer, block_address); |
swissChili | cbd4363 | 2021-07-17 16:19:44 -0700 | [diff] [blame] | 463 | |
| 464 | return true; |
swissChili | b7ef65d | 2021-07-17 12:51:52 -0700 | [diff] [blame] | 465 | } |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 466 | |
swissChili | 36ed5d7 | 2021-07-23 14:56:36 -0700 | [diff] [blame] | 467 | bool ext2_write_inode_block(struct ext2_superblock *sb, struct ext2_inode *dir, |
| 468 | void *buffer, uint block) |
| 469 | { |
| 470 | block = ext2_compute_absolute_block(sb, dir, block); |
| 471 | uint block_address = dir->blocks[block]; |
| 472 | |
| 473 | kprintf(DEBUG "Writing size=%d, inode block %p, b=%d\n", |
| 474 | ext2_block_size(sb), block_address * ext2_block_size(sb), block); |
| 475 | |
| 476 | ext2_write_block(sb, buffer, block_address); |
| 477 | |
| 478 | return true; |
| 479 | } |
| 480 | |
swissChili | e4229a2 | 2023-01-01 15:59:53 -0500 | [diff] [blame] | 481 | static uint ext2_bitmap_block(struct ext2_superblock *sb, |
| 482 | uint *bitmap_block, uint *index) |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 483 | { |
| 484 | const uint block_size = ext2_block_size(sb); |
| 485 | |
swissChili | caa2478 | 2021-07-19 14:29:58 -0700 | [diff] [blame] | 486 | while (*index > block_size) |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 487 | { |
swissChili | caa2478 | 2021-07-19 14:29:58 -0700 | [diff] [blame] | 488 | *index -= block_size; |
| 489 | *bitmap_block += 1; |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 490 | } |
| 491 | |
| 492 | return block_size; |
| 493 | } |
| 494 | |
| 495 | bool ext2_check_in_bitmap(struct ext2_superblock *sb, uint bitmap_block, |
| 496 | uint index) |
| 497 | { |
| 498 | const uint block_size = ext2_bitmap_block(sb, &bitmap_block, &index); |
| 499 | |
| 500 | uint byte = index / 8; |
| 501 | uint bit = index % 8; |
| 502 | |
| 503 | uchar buffer[block_size]; |
| 504 | |
| 505 | ext2_read_block(sb, buffer, bitmap_block); |
| 506 | |
| 507 | return !!(buffer[byte] & (1 << bit)); |
| 508 | } |
| 509 | |
| 510 | void ext2_set_in_bitmap(struct ext2_superblock *sb, uint bitmap_block, |
| 511 | uint index, bool value) |
| 512 | { |
| 513 | const uint block_size = ext2_bitmap_block(sb, &bitmap_block, &index); |
| 514 | |
| 515 | uint byte = index / 8; |
| 516 | uint bit = index % 8; |
| 517 | |
| 518 | uchar buffer[block_size]; |
| 519 | |
| 520 | ext2_read_block(sb, buffer, bitmap_block); |
| 521 | |
| 522 | uchar target_bit = 1 << bit; |
| 523 | buffer[byte] = |
| 524 | value ? (buffer[byte] | target_bit) : (buffer[byte] | ~target_bit); |
| 525 | |
| 526 | ext2_write_block(sb, buffer, bitmap_block); |
| 527 | } |
| 528 | |
| 529 | uint ext2_first_zero_bit(struct ext2_superblock *sb, uint bitmap_block, |
| 530 | uint num_blocks, uint start_at) |
| 531 | { |
| 532 | uint block_size = ext2_block_size(sb); |
| 533 | |
| 534 | for (uint block = bitmap_block; block < bitmap_block + num_blocks; block++) |
| 535 | { |
| 536 | // dword-array for performance |
| 537 | uint buffer[block_size / 4]; |
| 538 | |
| 539 | ext2_read_block(sb, buffer, block); |
| 540 | |
| 541 | // If this is the first block start at start_at, otherwise 0 |
swissChili | e4229a2 | 2023-01-01 15:59:53 -0500 | [diff] [blame] | 542 | for (uint i = 0; i < block_size / 4; i++) |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 543 | { |
| 544 | // The bitwise negative will be non-zero if there are zero bits in |
| 545 | // the original. |
| 546 | if (~buffer[i]) |
| 547 | { |
| 548 | // 4 bytes * 8 bits * i dwords |
| 549 | uint index = |
| 550 | (4 * 8 * i) + (block - bitmap_block) * 8 * block_size; |
| 551 | |
swissChili | caa2478 | 2021-07-19 14:29:58 -0700 | [diff] [blame] | 552 | // __builtin_ffs gives us 1+the index of the least-significant 1 |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 553 | // bit. Since we take the bitwise inverse this is actuall the |
| 554 | // least significant 0 bit. This is a GCC intrinsic. This works |
| 555 | // particularly well on little-endian systems where the least |
| 556 | // significant bit happens to also correspond to the first bit |
| 557 | // in the dword bitset. |
| 558 | // |
| 559 | // ________ ________ ________ ________ |
| 560 | // ^ this is the LSB ^ |
| 561 | // | this is the MSB |
| 562 | // |
| 563 | // This means that the LSB is also the first bit in the bitset. |
swissChili | caa2478 | 2021-07-19 14:29:58 -0700 | [diff] [blame] | 564 | uint trailing = __builtin_ffs(~buffer[i]) - 1; |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 565 | |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 566 | return trailing + index; |
| 567 | } |
| 568 | } |
| 569 | } |
| 570 | |
| 571 | return -1; |
| 572 | } |
| 573 | |
| 574 | uint ext2_first_free_inode(struct ext2_superblock *sb) |
| 575 | { |
swissChili | 36ed5d7 | 2021-07-23 14:56:36 -0700 | [diff] [blame] | 576 | uint num_block_groups = ext2_num_block_groups(sb); |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 577 | |
swissChili | 36ed5d7 | 2021-07-23 14:56:36 -0700 | [diff] [blame] | 578 | kprintf(INFO "%d block groups\n", num_block_groups); |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 579 | |
swissChili | e4229a2 | 2023-01-01 15:59:53 -0500 | [diff] [blame] | 580 | for (uint bg_num = 0; bg_num < num_block_groups; bg_num++) |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 581 | { |
swissChili | 36ed5d7 | 2021-07-23 14:56:36 -0700 | [diff] [blame] | 582 | struct ext2_block_group_descriptor bgd = |
swissChili | 480f176 | 2021-07-26 22:17:34 -0700 | [diff] [blame] | 583 | ext2_load_bgd(sb, 0); |
swissChili | 36ed5d7 | 2021-07-23 14:56:36 -0700 | [diff] [blame] | 584 | |
| 585 | const uint block_size = ext2_block_size(sb); |
| 586 | // + 1 because we need to round up (ie 1025 for 1024 size blocks will |
| 587 | // yield 1, should 2) |
| 588 | uint bitset_blocks = (sb->inodes_per_block_group / 8) / block_size + 1; |
| 589 | |
| 590 | // inodes start at 1 |
| 591 | uint inode = |
| 592 | ext2_first_zero_bit(sb, bgd.inode_bitmap, bitset_blocks, 12) + 1; |
| 593 | // This will overflow back to zero if no inode was found |
| 594 | |
| 595 | if (inode) |
| 596 | return inode; |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 597 | } |
| 598 | |
swissChili | 36ed5d7 | 2021-07-23 14:56:36 -0700 | [diff] [blame] | 599 | return 0; |
| 600 | } |
| 601 | |
| 602 | // ^ |
| 603 | // | this and | this are awfully similar, should refactor |
| 604 | // v |
| 605 | |
| 606 | uint ext2_first_free_block(struct ext2_superblock *sb) |
| 607 | { |
| 608 | uint num_block_groups = ext2_num_block_groups(sb); |
| 609 | |
swissChili | e4229a2 | 2023-01-01 15:59:53 -0500 | [diff] [blame] | 610 | for (uint bg_num = 0; bg_num < num_block_groups; bg_num++) |
swissChili | 36ed5d7 | 2021-07-23 14:56:36 -0700 | [diff] [blame] | 611 | { |
| 612 | struct ext2_block_group_descriptor bgd = |
swissChili | 480f176 | 2021-07-26 22:17:34 -0700 | [diff] [blame] | 613 | ext2_load_bgd(sb, 0); |
swissChili | 36ed5d7 | 2021-07-23 14:56:36 -0700 | [diff] [blame] | 614 | |
| 615 | const uint block_size = ext2_block_size(sb); |
| 616 | // + 1 because we need to round up (ie 1025 for 1024 size blocks will |
| 617 | // yield 1, should 2) |
| 618 | uint bitset_blocks = (sb->blocks_per_block_group / 8) / block_size + 1; |
| 619 | |
| 620 | // inodes start at 1 |
| 621 | uint block_no = |
| 622 | ext2_first_zero_bit(sb, bgd.block_bitmap, bitset_blocks, 0); |
| 623 | // This will overflow back to zero if no inode was found |
| 624 | |
| 625 | if (block_no != 0xffffffff) |
| 626 | return block_no; |
| 627 | } |
| 628 | |
| 629 | return 0; |
swissChili | 4749d02 | 2021-07-19 12:33:06 -0700 | [diff] [blame] | 630 | } |
swissChili | d98781b | 2021-07-25 21:04:17 -0700 | [diff] [blame] | 631 | |
| 632 | struct ext2_dir_contains_data |
| 633 | { |
| 634 | char *name; |
| 635 | uint len; |
| 636 | bool found; |
| 637 | }; |
| 638 | |
| 639 | static bool ext2_dir_contains_cb(uint inode, const char *name, |
| 640 | uint name_len, |
| 641 | struct ext2_dir_contains_data *d) |
| 642 | { |
| 643 | if (strncmp((char *)name, d->name, MIN(name_len, d->len)) == 0) |
| 644 | { |
| 645 | d->found = true; |
| 646 | return false; |
| 647 | } |
| 648 | |
| 649 | return true; |
| 650 | } |
| 651 | |
| 652 | bool ext2_dir_contains(struct ext2_superblock *sb, struct ext2_inode *dir, |
| 653 | char *name, uint len) |
| 654 | { |
| 655 | if ((dir->mode & EXT2_F_TYPE) != EXT2_S_IFDIR) |
| 656 | { |
| 657 | return false; |
| 658 | } |
| 659 | |
| 660 | struct ext2_dir_contains_data d = |
| 661 | { |
| 662 | .name = name, |
| 663 | .len = len, |
| 664 | .found = false, |
| 665 | }; |
| 666 | |
| 667 | ext2_dir_ls(sb, dir, ext2_dir_contains_cb, &d); |
| 668 | |
| 669 | return d.found; |
| 670 | } |
| 671 | |
| 672 | struct ext2_dir_find_data |
| 673 | { |
| 674 | char *name; |
| 675 | uint len; |
| 676 | uint inode; |
| 677 | }; |
| 678 | |
| 679 | bool ext2_dir_find_cb(uint inode, const char *name, uint len, |
| 680 | struct ext2_dir_find_data *d) |
| 681 | { |
| 682 | if (strncmp((char *)name, d->name, MIN(len, d->len)) == 0) |
| 683 | { |
| 684 | d->inode = inode; |
| 685 | return false; |
| 686 | } |
| 687 | |
| 688 | return true; |
| 689 | } |
| 690 | |
| 691 | uint ext2_dir_find(struct ext2_superblock *sb, struct ext2_inode *dir, |
| 692 | char *name, uint name_len) |
| 693 | { |
| 694 | if ((dir->mode & EXT2_F_TYPE) != EXT2_S_IFDIR) |
| 695 | { |
| 696 | return false; |
| 697 | } |
| 698 | |
| 699 | struct ext2_dir_find_data d = |
| 700 | { |
| 701 | .name = name, |
| 702 | .len = name_len, |
| 703 | .inode = 0, |
| 704 | }; |
| 705 | |
| 706 | ext2_dir_ls(sb, dir, ext2_dir_find_cb, &d); |
| 707 | |
| 708 | return d.inode; |
| 709 | } |
swissChili | 480f176 | 2021-07-26 22:17:34 -0700 | [diff] [blame] | 710 | |
| 711 | uint ext2_alloc_new_block(struct ext2_superblock *sb, |
| 712 | uint block_group) |
| 713 | { |
| 714 | struct ext2_block_group_descriptor bgd = |
| 715 | ext2_load_bgd(sb, block_group); |
| 716 | |
| 717 | if (bgd.unallocated_blocks == 0) |
| 718 | // TODO: handle out of blocks |
| 719 | return ext2_alloc_new_block(sb, block_group + 1); |
| 720 | |
| 721 | // We can safely pass ~0 here as long as the FS is well formed |
| 722 | // because we know there is at least 1 free block |
| 723 | uint block = ext2_first_zero_bit(sb, bgd.block_bitmap, ~0, 0); |
| 724 | |
| 725 | ext2_set_in_bitmap(sb, bgd.block_bitmap, block, true); |
| 726 | bgd.unallocated_blocks--; |
| 727 | |
| 728 | ext2_write_bgd(sb, block_group, &bgd); |
| 729 | |
| 730 | return block; |
| 731 | } |