Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * inode.c |
| 3 | * |
| 4 | * Copyright (c) 1999 Al Smith |
| 5 | * |
| 6 | * Portions derived from work (c) 1995,1996 Christian Vogelgsang, |
| 7 | * and from work (c) 1998 Mike Shaver. |
| 8 | */ |
| 9 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 10 | #include <linux/buffer_head.h> |
| 11 | #include <linux/module.h> |
| 12 | #include <linux/fs.h> |
Christoph Hellwig | 45254b4 | 2008-02-23 15:23:51 -0800 | [diff] [blame] | 13 | #include "efs.h" |
| 14 | #include <linux/efs_fs_sb.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | |
| 16 | static int efs_readpage(struct file *file, struct page *page) |
| 17 | { |
| 18 | return block_read_full_page(page,efs_get_block); |
| 19 | } |
| 20 | static sector_t _efs_bmap(struct address_space *mapping, sector_t block) |
| 21 | { |
| 22 | return generic_block_bmap(mapping,block,efs_get_block); |
| 23 | } |
Christoph Hellwig | f5e54d6 | 2006-06-28 04:26:44 -0700 | [diff] [blame] | 24 | static const struct address_space_operations efs_aops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | .readpage = efs_readpage, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 26 | .bmap = _efs_bmap |
| 27 | }; |
| 28 | |
| 29 | static inline void extent_copy(efs_extent *src, efs_extent *dst) { |
| 30 | /* |
| 31 | * this is slightly evil. it doesn't just copy |
| 32 | * efs_extent from src to dst, it also mangles |
| 33 | * the bits so that dst ends up in cpu byte-order. |
| 34 | */ |
| 35 | |
| 36 | dst->cooked.ex_magic = (unsigned int) src->raw[0]; |
| 37 | dst->cooked.ex_bn = ((unsigned int) src->raw[1] << 16) | |
| 38 | ((unsigned int) src->raw[2] << 8) | |
| 39 | ((unsigned int) src->raw[3] << 0); |
| 40 | dst->cooked.ex_length = (unsigned int) src->raw[4]; |
| 41 | dst->cooked.ex_offset = ((unsigned int) src->raw[5] << 16) | |
| 42 | ((unsigned int) src->raw[6] << 8) | |
| 43 | ((unsigned int) src->raw[7] << 0); |
| 44 | return; |
| 45 | } |
| 46 | |
David Howells | 298384cd | 2008-02-07 00:15:34 -0800 | [diff] [blame] | 47 | struct inode *efs_iget(struct super_block *super, unsigned long ino) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | { |
| 49 | int i, inode_index; |
| 50 | dev_t device; |
| 51 | u32 rdev; |
| 52 | struct buffer_head *bh; |
David Howells | 298384cd | 2008-02-07 00:15:34 -0800 | [diff] [blame] | 53 | struct efs_sb_info *sb = SUPER_INFO(super); |
| 54 | struct efs_inode_info *in; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 55 | efs_block_t block, offset; |
| 56 | struct efs_dinode *efs_inode; |
David Howells | 298384cd | 2008-02-07 00:15:34 -0800 | [diff] [blame] | 57 | struct inode *inode; |
| 58 | |
| 59 | inode = iget_locked(super, ino); |
Dan Carpenter | 136eefa | 2013-08-14 12:49:40 +0300 | [diff] [blame] | 60 | if (!inode) |
David Howells | 298384cd | 2008-02-07 00:15:34 -0800 | [diff] [blame] | 61 | return ERR_PTR(-ENOMEM); |
| 62 | if (!(inode->i_state & I_NEW)) |
| 63 | return inode; |
| 64 | |
| 65 | in = INODE_INFO(inode); |
| 66 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 67 | /* |
| 68 | ** EFS layout: |
| 69 | ** |
| 70 | ** | cylinder group | cylinder group | cylinder group ..etc |
| 71 | ** |inodes|data |inodes|data |inodes|data ..etc |
| 72 | ** |
| 73 | ** work out the inode block index, (considering initially that the |
| 74 | ** inodes are stored as consecutive blocks). then work out the block |
| 75 | ** number of that inode given the above layout, and finally the |
| 76 | ** offset of the inode within that block. |
| 77 | */ |
| 78 | |
| 79 | inode_index = inode->i_ino / |
| 80 | (EFS_BLOCKSIZE / sizeof(struct efs_dinode)); |
| 81 | |
| 82 | block = sb->fs_start + sb->first_block + |
| 83 | (sb->group_size * (inode_index / sb->inode_blocks)) + |
| 84 | (inode_index % sb->inode_blocks); |
| 85 | |
| 86 | offset = (inode->i_ino % |
| 87 | (EFS_BLOCKSIZE / sizeof(struct efs_dinode))) * |
| 88 | sizeof(struct efs_dinode); |
| 89 | |
| 90 | bh = sb_bread(inode->i_sb, block); |
| 91 | if (!bh) { |
| 92 | printk(KERN_WARNING "EFS: bread() failed at block %d\n", block); |
| 93 | goto read_inode_error; |
| 94 | } |
| 95 | |
| 96 | efs_inode = (struct efs_dinode *) (bh->b_data + offset); |
| 97 | |
| 98 | inode->i_mode = be16_to_cpu(efs_inode->di_mode); |
Miklos Szeredi | bfe8684 | 2011-10-28 14:13:29 +0200 | [diff] [blame] | 99 | set_nlink(inode, be16_to_cpu(efs_inode->di_nlink)); |
Eric W. Biederman | 5d4ea4d | 2012-02-10 11:10:33 -0800 | [diff] [blame] | 100 | i_uid_write(inode, (uid_t)be16_to_cpu(efs_inode->di_uid)); |
| 101 | i_gid_write(inode, (gid_t)be16_to_cpu(efs_inode->di_gid)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 102 | inode->i_size = be32_to_cpu(efs_inode->di_size); |
| 103 | inode->i_atime.tv_sec = be32_to_cpu(efs_inode->di_atime); |
| 104 | inode->i_mtime.tv_sec = be32_to_cpu(efs_inode->di_mtime); |
| 105 | inode->i_ctime.tv_sec = be32_to_cpu(efs_inode->di_ctime); |
| 106 | inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0; |
| 107 | |
| 108 | /* this is the number of blocks in the file */ |
| 109 | if (inode->i_size == 0) { |
| 110 | inode->i_blocks = 0; |
| 111 | } else { |
| 112 | inode->i_blocks = ((inode->i_size - 1) >> EFS_BLOCKSIZE_BITS) + 1; |
| 113 | } |
| 114 | |
| 115 | rdev = be16_to_cpu(efs_inode->di_u.di_dev.odev); |
| 116 | if (rdev == 0xffff) { |
| 117 | rdev = be32_to_cpu(efs_inode->di_u.di_dev.ndev); |
| 118 | if (sysv_major(rdev) > 0xfff) |
| 119 | device = 0; |
| 120 | else |
| 121 | device = MKDEV(sysv_major(rdev), sysv_minor(rdev)); |
| 122 | } else |
| 123 | device = old_decode_dev(rdev); |
| 124 | |
| 125 | /* get the number of extents for this object */ |
| 126 | in->numextents = be16_to_cpu(efs_inode->di_numextents); |
| 127 | in->lastextent = 0; |
| 128 | |
| 129 | /* copy the extents contained within the inode to memory */ |
| 130 | for(i = 0; i < EFS_DIRECTEXTENTS; i++) { |
| 131 | extent_copy(&(efs_inode->di_u.di_extents[i]), &(in->extents[i])); |
| 132 | if (i < in->numextents && in->extents[i].cooked.ex_magic != 0) { |
| 133 | printk(KERN_WARNING "EFS: extent %d has bad magic number in inode %lu\n", i, inode->i_ino); |
| 134 | brelse(bh); |
| 135 | goto read_inode_error; |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | brelse(bh); |
| 140 | |
| 141 | #ifdef DEBUG |
Robert P. J. Day | 865965a | 2008-04-02 13:04:49 -0700 | [diff] [blame] | 142 | printk(KERN_DEBUG "EFS: efs_iget(): inode %lu, extents %d, mode %o\n", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 143 | inode->i_ino, in->numextents, inode->i_mode); |
| 144 | #endif |
| 145 | |
| 146 | switch (inode->i_mode & S_IFMT) { |
| 147 | case S_IFDIR: |
| 148 | inode->i_op = &efs_dir_inode_operations; |
| 149 | inode->i_fop = &efs_dir_operations; |
| 150 | break; |
| 151 | case S_IFREG: |
| 152 | inode->i_fop = &generic_ro_fops; |
| 153 | inode->i_data.a_ops = &efs_aops; |
| 154 | break; |
| 155 | case S_IFLNK: |
| 156 | inode->i_op = &page_symlink_inode_operations; |
| 157 | inode->i_data.a_ops = &efs_symlink_aops; |
| 158 | break; |
| 159 | case S_IFCHR: |
| 160 | case S_IFBLK: |
| 161 | case S_IFIFO: |
| 162 | init_special_inode(inode, inode->i_mode, device); |
| 163 | break; |
| 164 | default: |
| 165 | printk(KERN_WARNING "EFS: unsupported inode mode %o\n", inode->i_mode); |
| 166 | goto read_inode_error; |
| 167 | break; |
| 168 | } |
| 169 | |
David Howells | 298384cd | 2008-02-07 00:15:34 -0800 | [diff] [blame] | 170 | unlock_new_inode(inode); |
| 171 | return inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 172 | |
| 173 | read_inode_error: |
| 174 | printk(KERN_WARNING "EFS: failed to read inode %lu\n", inode->i_ino); |
David Howells | 298384cd | 2008-02-07 00:15:34 -0800 | [diff] [blame] | 175 | iget_failed(inode); |
| 176 | return ERR_PTR(-EIO); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | } |
| 178 | |
| 179 | static inline efs_block_t |
| 180 | efs_extent_check(efs_extent *ptr, efs_block_t block, struct efs_sb_info *sb) { |
| 181 | efs_block_t start; |
| 182 | efs_block_t length; |
| 183 | efs_block_t offset; |
| 184 | |
| 185 | /* |
| 186 | * given an extent and a logical block within a file, |
| 187 | * can this block be found within this extent ? |
| 188 | */ |
| 189 | start = ptr->cooked.ex_bn; |
| 190 | length = ptr->cooked.ex_length; |
| 191 | offset = ptr->cooked.ex_offset; |
| 192 | |
| 193 | if ((block >= offset) && (block < offset+length)) { |
| 194 | return(sb->fs_start + start + block - offset); |
| 195 | } else { |
| 196 | return 0; |
| 197 | } |
| 198 | } |
| 199 | |
| 200 | efs_block_t efs_map_block(struct inode *inode, efs_block_t block) { |
| 201 | struct efs_sb_info *sb = SUPER_INFO(inode->i_sb); |
| 202 | struct efs_inode_info *in = INODE_INFO(inode); |
| 203 | struct buffer_head *bh = NULL; |
| 204 | |
| 205 | int cur, last, first = 1; |
| 206 | int ibase, ioffset, dirext, direxts, indext, indexts; |
| 207 | efs_block_t iblock, result = 0, lastblock = 0; |
| 208 | efs_extent ext, *exts; |
| 209 | |
| 210 | last = in->lastextent; |
| 211 | |
| 212 | if (in->numextents <= EFS_DIRECTEXTENTS) { |
| 213 | /* first check the last extent we returned */ |
| 214 | if ((result = efs_extent_check(&in->extents[last], block, sb))) |
| 215 | return result; |
| 216 | |
| 217 | /* if we only have one extent then nothing can be found */ |
| 218 | if (in->numextents == 1) { |
| 219 | printk(KERN_ERR "EFS: map_block() failed to map (1 extent)\n"); |
| 220 | return 0; |
| 221 | } |
| 222 | |
| 223 | direxts = in->numextents; |
| 224 | |
| 225 | /* |
| 226 | * check the stored extents in the inode |
| 227 | * start with next extent and check forwards |
| 228 | */ |
| 229 | for(dirext = 1; dirext < direxts; dirext++) { |
| 230 | cur = (last + dirext) % in->numextents; |
| 231 | if ((result = efs_extent_check(&in->extents[cur], block, sb))) { |
| 232 | in->lastextent = cur; |
| 233 | return result; |
| 234 | } |
| 235 | } |
| 236 | |
| 237 | printk(KERN_ERR "EFS: map_block() failed to map block %u (dir)\n", block); |
| 238 | return 0; |
| 239 | } |
| 240 | |
| 241 | #ifdef DEBUG |
| 242 | printk(KERN_DEBUG "EFS: map_block(): indirect search for logical block %u\n", block); |
| 243 | #endif |
| 244 | direxts = in->extents[0].cooked.ex_offset; |
| 245 | indexts = in->numextents; |
| 246 | |
| 247 | for(indext = 0; indext < indexts; indext++) { |
| 248 | cur = (last + indext) % indexts; |
| 249 | |
| 250 | /* |
| 251 | * work out which direct extent contains `cur'. |
| 252 | * |
| 253 | * also compute ibase: i.e. the number of the first |
| 254 | * indirect extent contained within direct extent `cur'. |
| 255 | * |
| 256 | */ |
| 257 | ibase = 0; |
| 258 | for(dirext = 0; cur < ibase && dirext < direxts; dirext++) { |
| 259 | ibase += in->extents[dirext].cooked.ex_length * |
| 260 | (EFS_BLOCKSIZE / sizeof(efs_extent)); |
| 261 | } |
| 262 | |
| 263 | if (dirext == direxts) { |
| 264 | /* should never happen */ |
| 265 | printk(KERN_ERR "EFS: couldn't find direct extent for indirect extent %d (block %u)\n", cur, block); |
| 266 | if (bh) brelse(bh); |
| 267 | return 0; |
| 268 | } |
| 269 | |
| 270 | /* work out block number and offset of this indirect extent */ |
| 271 | iblock = sb->fs_start + in->extents[dirext].cooked.ex_bn + |
| 272 | (cur - ibase) / |
| 273 | (EFS_BLOCKSIZE / sizeof(efs_extent)); |
| 274 | ioffset = (cur - ibase) % |
| 275 | (EFS_BLOCKSIZE / sizeof(efs_extent)); |
| 276 | |
| 277 | if (first || lastblock != iblock) { |
| 278 | if (bh) brelse(bh); |
| 279 | |
| 280 | bh = sb_bread(inode->i_sb, iblock); |
| 281 | if (!bh) { |
| 282 | printk(KERN_ERR "EFS: bread() failed at block %d\n", iblock); |
| 283 | return 0; |
| 284 | } |
| 285 | #ifdef DEBUG |
| 286 | printk(KERN_DEBUG "EFS: map_block(): read indirect extent block %d\n", iblock); |
| 287 | #endif |
| 288 | first = 0; |
| 289 | lastblock = iblock; |
| 290 | } |
| 291 | |
| 292 | exts = (efs_extent *) bh->b_data; |
| 293 | |
| 294 | extent_copy(&(exts[ioffset]), &ext); |
| 295 | |
| 296 | if (ext.cooked.ex_magic != 0) { |
| 297 | printk(KERN_ERR "EFS: extent %d has bad magic number in block %d\n", cur, iblock); |
| 298 | if (bh) brelse(bh); |
| 299 | return 0; |
| 300 | } |
| 301 | |
| 302 | if ((result = efs_extent_check(&ext, block, sb))) { |
| 303 | if (bh) brelse(bh); |
| 304 | in->lastextent = cur; |
| 305 | return result; |
| 306 | } |
| 307 | } |
| 308 | if (bh) brelse(bh); |
| 309 | printk(KERN_ERR "EFS: map_block() failed to map block %u (indir)\n", block); |
| 310 | return 0; |
| 311 | } |
| 312 | |
| 313 | MODULE_LICENSE("GPL"); |