1c93d8f88SEric Biggers // SPDX-License-Identifier: GPL-2.0 2c93d8f88SEric Biggers /* 3c93d8f88SEric Biggers * fs/ext4/verity.c: fs-verity support for ext4 4c93d8f88SEric Biggers * 5c93d8f88SEric Biggers * Copyright 2019 Google LLC 6c93d8f88SEric Biggers */ 7c93d8f88SEric Biggers 8c93d8f88SEric Biggers /* 9c93d8f88SEric Biggers * Implementation of fsverity_operations for ext4. 10c93d8f88SEric Biggers * 11c93d8f88SEric Biggers * ext4 stores the verity metadata (Merkle tree and fsverity_descriptor) past 12c93d8f88SEric Biggers * the end of the file, starting at the first 64K boundary beyond i_size. This 13c93d8f88SEric Biggers * approach works because (a) verity files are readonly, and (b) pages fully 14c93d8f88SEric Biggers * beyond i_size aren't visible to userspace but can be read/written internally 15c93d8f88SEric Biggers * by ext4 with only some relatively small changes to ext4. This approach 16c93d8f88SEric Biggers * avoids having to depend on the EA_INODE feature and on rearchitecturing 17c93d8f88SEric Biggers * ext4's xattr support to support paging multi-gigabyte xattrs into memory, and 18c93d8f88SEric Biggers * to support encrypting xattrs. Note that the verity metadata *must* be 19c93d8f88SEric Biggers * encrypted when the file is, since it contains hashes of the plaintext data. 20c93d8f88SEric Biggers * 21c93d8f88SEric Biggers * Using a 64K boundary rather than a 4K one keeps things ready for 22c93d8f88SEric Biggers * architectures with 64K pages, and it doesn't necessarily waste space on-disk 23c93d8f88SEric Biggers * since there can be a hole between i_size and the start of the Merkle tree. 24c93d8f88SEric Biggers */ 25c93d8f88SEric Biggers 26c93d8f88SEric Biggers #include <linux/quotaops.h> 27c93d8f88SEric Biggers 28c93d8f88SEric Biggers #include "ext4.h" 29c93d8f88SEric Biggers #include "ext4_extents.h" 30c93d8f88SEric Biggers #include "ext4_jbd2.h" 31c93d8f88SEric Biggers 32c93d8f88SEric Biggers static inline loff_t ext4_verity_metadata_pos(const struct inode *inode) 33c93d8f88SEric Biggers { 34c93d8f88SEric Biggers return round_up(inode->i_size, 65536); 35c93d8f88SEric Biggers } 36c93d8f88SEric Biggers 37c93d8f88SEric Biggers /* 38c93d8f88SEric Biggers * Read some verity metadata from the inode. __vfs_read() can't be used because 39c93d8f88SEric Biggers * we need to read beyond i_size. 40c93d8f88SEric Biggers */ 41c93d8f88SEric Biggers static int pagecache_read(struct inode *inode, void *buf, size_t count, 42c93d8f88SEric Biggers loff_t pos) 43c93d8f88SEric Biggers { 44c93d8f88SEric Biggers while (count) { 45c93d8f88SEric Biggers size_t n = min_t(size_t, count, 46c93d8f88SEric Biggers PAGE_SIZE - offset_in_page(pos)); 47c93d8f88SEric Biggers struct page *page; 48c93d8f88SEric Biggers 49c93d8f88SEric Biggers page = read_mapping_page(inode->i_mapping, pos >> PAGE_SHIFT, 50c93d8f88SEric Biggers NULL); 51c93d8f88SEric Biggers if (IS_ERR(page)) 52c93d8f88SEric Biggers return PTR_ERR(page); 53c93d8f88SEric Biggers 544d93874bSChaitanya Kulkarni memcpy_from_page(buf, page, offset_in_page(pos), n); 55c93d8f88SEric Biggers 56c93d8f88SEric Biggers put_page(page); 57c93d8f88SEric Biggers 58c93d8f88SEric Biggers buf += n; 59c93d8f88SEric Biggers pos += n; 60c93d8f88SEric Biggers count -= n; 61c93d8f88SEric Biggers } 62c93d8f88SEric Biggers return 0; 63c93d8f88SEric Biggers } 64c93d8f88SEric Biggers 65c93d8f88SEric Biggers /* 66c93d8f88SEric Biggers * Write some verity metadata to the inode for FS_IOC_ENABLE_VERITY. 67c93d8f88SEric Biggers * kernel_write() can't be used because the file descriptor is readonly. 68c93d8f88SEric Biggers */ 69c93d8f88SEric Biggers static int pagecache_write(struct inode *inode, const void *buf, size_t count, 70c93d8f88SEric Biggers loff_t pos) 71c93d8f88SEric Biggers { 721b0aa444SMatthew Wilcox (Oracle) struct address_space *mapping = inode->i_mapping; 731b0aa444SMatthew Wilcox (Oracle) const struct address_space_operations *aops = mapping->a_ops; 741b0aa444SMatthew Wilcox (Oracle) 75c93d8f88SEric Biggers if (pos + count > inode->i_sb->s_maxbytes) 76c93d8f88SEric Biggers return -EFBIG; 77c93d8f88SEric Biggers 78c93d8f88SEric Biggers while (count) { 79c93d8f88SEric Biggers size_t n = min_t(size_t, count, 80c93d8f88SEric Biggers PAGE_SIZE - offset_in_page(pos)); 81c93d8f88SEric Biggers struct page *page; 82*956510c0SAlexander Potapenko void *fsdata = NULL; 83c93d8f88SEric Biggers int res; 84c93d8f88SEric Biggers 851b0aa444SMatthew Wilcox (Oracle) res = aops->write_begin(NULL, mapping, pos, n, &page, &fsdata); 86c93d8f88SEric Biggers if (res) 87c93d8f88SEric Biggers return res; 88c93d8f88SEric Biggers 89bd256fdaSChaitanya Kulkarni memcpy_to_page(page, offset_in_page(pos), buf, n); 90c93d8f88SEric Biggers 911b0aa444SMatthew Wilcox (Oracle) res = aops->write_end(NULL, mapping, pos, n, n, page, fsdata); 92c93d8f88SEric Biggers if (res < 0) 93c93d8f88SEric Biggers return res; 94c93d8f88SEric Biggers if (res != n) 95c93d8f88SEric Biggers return -EIO; 96c93d8f88SEric Biggers 97c93d8f88SEric Biggers buf += n; 98c93d8f88SEric Biggers pos += n; 99c93d8f88SEric Biggers count -= n; 100c93d8f88SEric Biggers } 101c93d8f88SEric Biggers return 0; 102c93d8f88SEric Biggers } 103c93d8f88SEric Biggers 104c93d8f88SEric Biggers static int ext4_begin_enable_verity(struct file *filp) 105c93d8f88SEric Biggers { 106c93d8f88SEric Biggers struct inode *inode = file_inode(filp); 107c93d8f88SEric Biggers const int credits = 2; /* superblock and inode for ext4_orphan_add() */ 108c93d8f88SEric Biggers handle_t *handle; 109c93d8f88SEric Biggers int err; 110c93d8f88SEric Biggers 111b383a73fSIra Weiny if (IS_DAX(inode) || ext4_test_inode_flag(inode, EXT4_INODE_DAX)) 1126c0d077fSIra Weiny return -EINVAL; 1136c0d077fSIra Weiny 114c93d8f88SEric Biggers if (ext4_verity_in_progress(inode)) 115c93d8f88SEric Biggers return -EBUSY; 116c93d8f88SEric Biggers 117c93d8f88SEric Biggers /* 118c93d8f88SEric Biggers * Since the file was opened readonly, we have to initialize the jbd 119c93d8f88SEric Biggers * inode and quotas here and not rely on ->open() doing it. This must 120c93d8f88SEric Biggers * be done before evicting the inline data. 121c93d8f88SEric Biggers */ 122c93d8f88SEric Biggers 123c93d8f88SEric Biggers err = ext4_inode_attach_jinode(inode); 124c93d8f88SEric Biggers if (err) 125c93d8f88SEric Biggers return err; 126c93d8f88SEric Biggers 127c93d8f88SEric Biggers err = dquot_initialize(inode); 128c93d8f88SEric Biggers if (err) 129c93d8f88SEric Biggers return err; 130c93d8f88SEric Biggers 131c93d8f88SEric Biggers err = ext4_convert_inline_data(inode); 132c93d8f88SEric Biggers if (err) 133c93d8f88SEric Biggers return err; 134c93d8f88SEric Biggers 135c93d8f88SEric Biggers if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { 136c93d8f88SEric Biggers ext4_warning_inode(inode, 137c93d8f88SEric Biggers "verity is only allowed on extent-based files"); 138c93d8f88SEric Biggers return -EOPNOTSUPP; 139c93d8f88SEric Biggers } 140c93d8f88SEric Biggers 141c93d8f88SEric Biggers /* 142c93d8f88SEric Biggers * ext4 uses the last allocated block to find the verity descriptor, so 143c93d8f88SEric Biggers * we must remove any other blocks past EOF which might confuse things. 144c93d8f88SEric Biggers */ 145c93d8f88SEric Biggers err = ext4_truncate(inode); 146c93d8f88SEric Biggers if (err) 147c93d8f88SEric Biggers return err; 148c93d8f88SEric Biggers 149c93d8f88SEric Biggers handle = ext4_journal_start(inode, EXT4_HT_INODE, credits); 150c93d8f88SEric Biggers if (IS_ERR(handle)) 151c93d8f88SEric Biggers return PTR_ERR(handle); 152c93d8f88SEric Biggers 153c93d8f88SEric Biggers err = ext4_orphan_add(handle, inode); 154c93d8f88SEric Biggers if (err == 0) 155c93d8f88SEric Biggers ext4_set_inode_state(inode, EXT4_STATE_VERITY_IN_PROGRESS); 156c93d8f88SEric Biggers 157c93d8f88SEric Biggers ext4_journal_stop(handle); 158c93d8f88SEric Biggers return err; 159c93d8f88SEric Biggers } 160c93d8f88SEric Biggers 161c93d8f88SEric Biggers /* 162c93d8f88SEric Biggers * ext4 stores the verity descriptor beginning on the next filesystem block 163c93d8f88SEric Biggers * boundary after the Merkle tree. Then, the descriptor size is stored in the 164c93d8f88SEric Biggers * last 4 bytes of the last allocated filesystem block --- which is either the 165c93d8f88SEric Biggers * block in which the descriptor ends, or the next block after that if there 166c93d8f88SEric Biggers * weren't at least 4 bytes remaining. 167c93d8f88SEric Biggers * 168c93d8f88SEric Biggers * We can't simply store the descriptor in an xattr because it *must* be 169c93d8f88SEric Biggers * encrypted when ext4 encryption is used, but ext4 encryption doesn't encrypt 170c93d8f88SEric Biggers * xattrs. Also, if the descriptor includes a large signature blob it may be 171c93d8f88SEric Biggers * too large to store in an xattr without the EA_INODE feature. 172c93d8f88SEric Biggers */ 173c93d8f88SEric Biggers static int ext4_write_verity_descriptor(struct inode *inode, const void *desc, 174c93d8f88SEric Biggers size_t desc_size, u64 merkle_tree_size) 175c93d8f88SEric Biggers { 176c93d8f88SEric Biggers const u64 desc_pos = round_up(ext4_verity_metadata_pos(inode) + 177c93d8f88SEric Biggers merkle_tree_size, i_blocksize(inode)); 178c93d8f88SEric Biggers const u64 desc_end = desc_pos + desc_size; 179c93d8f88SEric Biggers const __le32 desc_size_disk = cpu_to_le32(desc_size); 180c93d8f88SEric Biggers const u64 desc_size_pos = round_up(desc_end + sizeof(desc_size_disk), 181c93d8f88SEric Biggers i_blocksize(inode)) - 182c93d8f88SEric Biggers sizeof(desc_size_disk); 183c93d8f88SEric Biggers int err; 184c93d8f88SEric Biggers 185c93d8f88SEric Biggers err = pagecache_write(inode, desc, desc_size, desc_pos); 186c93d8f88SEric Biggers if (err) 187c93d8f88SEric Biggers return err; 188c93d8f88SEric Biggers 189c93d8f88SEric Biggers return pagecache_write(inode, &desc_size_disk, sizeof(desc_size_disk), 190c93d8f88SEric Biggers desc_size_pos); 191c93d8f88SEric Biggers } 192c93d8f88SEric Biggers 193c93d8f88SEric Biggers static int ext4_end_enable_verity(struct file *filp, const void *desc, 194c93d8f88SEric Biggers size_t desc_size, u64 merkle_tree_size) 195c93d8f88SEric Biggers { 196c93d8f88SEric Biggers struct inode *inode = file_inode(filp); 197c93d8f88SEric Biggers const int credits = 2; /* superblock and inode for ext4_orphan_del() */ 198c93d8f88SEric Biggers handle_t *handle; 199f053cf7aSEric Biggers struct ext4_iloc iloc; 200c93d8f88SEric Biggers int err = 0; 201c93d8f88SEric Biggers 202c93d8f88SEric Biggers /* 203f053cf7aSEric Biggers * If an error already occurred (which fs/verity/ signals by passing 204f053cf7aSEric Biggers * desc == NULL), then only clean-up is needed. 205c93d8f88SEric Biggers */ 206f053cf7aSEric Biggers if (desc == NULL) 207f053cf7aSEric Biggers goto cleanup; 208c93d8f88SEric Biggers 209f053cf7aSEric Biggers /* Append the verity descriptor. */ 210f053cf7aSEric Biggers err = ext4_write_verity_descriptor(inode, desc, desc_size, 211f053cf7aSEric Biggers merkle_tree_size); 212f053cf7aSEric Biggers if (err) 213f053cf7aSEric Biggers goto cleanup; 214f053cf7aSEric Biggers 215f053cf7aSEric Biggers /* 216f053cf7aSEric Biggers * Write all pages (both data and verity metadata). Note that this must 217f053cf7aSEric Biggers * happen before clearing EXT4_STATE_VERITY_IN_PROGRESS; otherwise pages 218f053cf7aSEric Biggers * beyond i_size won't be written properly. For crash consistency, this 219f053cf7aSEric Biggers * also must happen before the verity inode flag gets persisted. 220f053cf7aSEric Biggers */ 221f053cf7aSEric Biggers err = filemap_write_and_wait(inode->i_mapping); 222f053cf7aSEric Biggers if (err) 223f053cf7aSEric Biggers goto cleanup; 224f053cf7aSEric Biggers 225f053cf7aSEric Biggers /* 226f053cf7aSEric Biggers * Finally, set the verity inode flag and remove the inode from the 227f053cf7aSEric Biggers * orphan list (in a single transaction). 228f053cf7aSEric Biggers */ 229c93d8f88SEric Biggers 230c93d8f88SEric Biggers handle = ext4_journal_start(inode, EXT4_HT_INODE, credits); 231c93d8f88SEric Biggers if (IS_ERR(handle)) { 232f053cf7aSEric Biggers err = PTR_ERR(handle); 233f053cf7aSEric Biggers goto cleanup; 234c93d8f88SEric Biggers } 235c93d8f88SEric Biggers 236f053cf7aSEric Biggers err = ext4_orphan_del(handle, inode); 237f053cf7aSEric Biggers if (err) 238f053cf7aSEric Biggers goto stop_and_cleanup; 239c93d8f88SEric Biggers 240c93d8f88SEric Biggers err = ext4_reserve_inode_write(handle, inode, &iloc); 241c93d8f88SEric Biggers if (err) 242f053cf7aSEric Biggers goto stop_and_cleanup; 243f053cf7aSEric Biggers 244c93d8f88SEric Biggers ext4_set_inode_flag(inode, EXT4_INODE_VERITY); 245043546e4SIra Weiny ext4_set_inode_flags(inode, false); 246c93d8f88SEric Biggers err = ext4_mark_iloc_dirty(handle, inode, &iloc); 247f053cf7aSEric Biggers if (err) 248f053cf7aSEric Biggers goto stop_and_cleanup; 249f053cf7aSEric Biggers 250c93d8f88SEric Biggers ext4_journal_stop(handle); 251f053cf7aSEric Biggers 252f053cf7aSEric Biggers ext4_clear_inode_state(inode, EXT4_STATE_VERITY_IN_PROGRESS); 253f053cf7aSEric Biggers return 0; 254f053cf7aSEric Biggers 255f053cf7aSEric Biggers stop_and_cleanup: 256f053cf7aSEric Biggers ext4_journal_stop(handle); 257f053cf7aSEric Biggers cleanup: 258f053cf7aSEric Biggers /* 259f053cf7aSEric Biggers * Verity failed to be enabled, so clean up by truncating any verity 260f053cf7aSEric Biggers * metadata that was written beyond i_size (both from cache and from 261f053cf7aSEric Biggers * disk), removing the inode from the orphan list (if it wasn't done 262f053cf7aSEric Biggers * already), and clearing EXT4_STATE_VERITY_IN_PROGRESS. 263f053cf7aSEric Biggers */ 264f053cf7aSEric Biggers truncate_inode_pages(inode->i_mapping, inode->i_size); 265f053cf7aSEric Biggers ext4_truncate(inode); 266f053cf7aSEric Biggers ext4_orphan_del(NULL, inode); 267f053cf7aSEric Biggers ext4_clear_inode_state(inode, EXT4_STATE_VERITY_IN_PROGRESS); 268f053cf7aSEric Biggers return err; 269c93d8f88SEric Biggers } 270c93d8f88SEric Biggers 271c93d8f88SEric Biggers static int ext4_get_verity_descriptor_location(struct inode *inode, 272c93d8f88SEric Biggers size_t *desc_size_ret, 273c93d8f88SEric Biggers u64 *desc_pos_ret) 274c93d8f88SEric Biggers { 275c93d8f88SEric Biggers struct ext4_ext_path *path; 276c93d8f88SEric Biggers struct ext4_extent *last_extent; 277c93d8f88SEric Biggers u32 end_lblk; 278c93d8f88SEric Biggers u64 desc_size_pos; 279c93d8f88SEric Biggers __le32 desc_size_disk; 280c93d8f88SEric Biggers u32 desc_size; 281c93d8f88SEric Biggers u64 desc_pos; 282c93d8f88SEric Biggers int err; 283c93d8f88SEric Biggers 284c93d8f88SEric Biggers /* 285c93d8f88SEric Biggers * Descriptor size is in last 4 bytes of last allocated block. 286c93d8f88SEric Biggers * See ext4_write_verity_descriptor(). 287c93d8f88SEric Biggers */ 288c93d8f88SEric Biggers 289c93d8f88SEric Biggers if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { 290c93d8f88SEric Biggers EXT4_ERROR_INODE(inode, "verity file doesn't use extents"); 291c93d8f88SEric Biggers return -EFSCORRUPTED; 292c93d8f88SEric Biggers } 293c93d8f88SEric Biggers 294c93d8f88SEric Biggers path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL, 0); 295c93d8f88SEric Biggers if (IS_ERR(path)) 296c93d8f88SEric Biggers return PTR_ERR(path); 297c93d8f88SEric Biggers 298c93d8f88SEric Biggers last_extent = path[path->p_depth].p_ext; 299c93d8f88SEric Biggers if (!last_extent) { 300c93d8f88SEric Biggers EXT4_ERROR_INODE(inode, "verity file has no extents"); 3017ff5fddaSYe Bin ext4_free_ext_path(path); 302c93d8f88SEric Biggers return -EFSCORRUPTED; 303c93d8f88SEric Biggers } 304c93d8f88SEric Biggers 305c93d8f88SEric Biggers end_lblk = le32_to_cpu(last_extent->ee_block) + 306c93d8f88SEric Biggers ext4_ext_get_actual_len(last_extent); 307c93d8f88SEric Biggers desc_size_pos = (u64)end_lblk << inode->i_blkbits; 3087ff5fddaSYe Bin ext4_free_ext_path(path); 309c93d8f88SEric Biggers 310c93d8f88SEric Biggers if (desc_size_pos < sizeof(desc_size_disk)) 311c93d8f88SEric Biggers goto bad; 312c93d8f88SEric Biggers desc_size_pos -= sizeof(desc_size_disk); 313c93d8f88SEric Biggers 314c93d8f88SEric Biggers err = pagecache_read(inode, &desc_size_disk, sizeof(desc_size_disk), 315c93d8f88SEric Biggers desc_size_pos); 316c93d8f88SEric Biggers if (err) 317c93d8f88SEric Biggers return err; 318c93d8f88SEric Biggers desc_size = le32_to_cpu(desc_size_disk); 319c93d8f88SEric Biggers 320c93d8f88SEric Biggers /* 321c93d8f88SEric Biggers * The descriptor is stored just before the desc_size_disk, but starting 322c93d8f88SEric Biggers * on a filesystem block boundary. 323c93d8f88SEric Biggers */ 324c93d8f88SEric Biggers 325c93d8f88SEric Biggers if (desc_size > INT_MAX || desc_size > desc_size_pos) 326c93d8f88SEric Biggers goto bad; 327c93d8f88SEric Biggers 328c93d8f88SEric Biggers desc_pos = round_down(desc_size_pos - desc_size, i_blocksize(inode)); 329c93d8f88SEric Biggers if (desc_pos < ext4_verity_metadata_pos(inode)) 330c93d8f88SEric Biggers goto bad; 331c93d8f88SEric Biggers 332c93d8f88SEric Biggers *desc_size_ret = desc_size; 333c93d8f88SEric Biggers *desc_pos_ret = desc_pos; 334c93d8f88SEric Biggers return 0; 335c93d8f88SEric Biggers 336c93d8f88SEric Biggers bad: 337c93d8f88SEric Biggers EXT4_ERROR_INODE(inode, "verity file corrupted; can't find descriptor"); 338c93d8f88SEric Biggers return -EFSCORRUPTED; 339c93d8f88SEric Biggers } 340c93d8f88SEric Biggers 341c93d8f88SEric Biggers static int ext4_get_verity_descriptor(struct inode *inode, void *buf, 342c93d8f88SEric Biggers size_t buf_size) 343c93d8f88SEric Biggers { 344c93d8f88SEric Biggers size_t desc_size = 0; 345c93d8f88SEric Biggers u64 desc_pos = 0; 346c93d8f88SEric Biggers int err; 347c93d8f88SEric Biggers 348c93d8f88SEric Biggers err = ext4_get_verity_descriptor_location(inode, &desc_size, &desc_pos); 349c93d8f88SEric Biggers if (err) 350c93d8f88SEric Biggers return err; 351c93d8f88SEric Biggers 352c93d8f88SEric Biggers if (buf_size) { 353c93d8f88SEric Biggers if (desc_size > buf_size) 354c93d8f88SEric Biggers return -ERANGE; 355c93d8f88SEric Biggers err = pagecache_read(inode, buf, desc_size, desc_pos); 356c93d8f88SEric Biggers if (err) 357c93d8f88SEric Biggers return err; 358c93d8f88SEric Biggers } 359c93d8f88SEric Biggers return desc_size; 360c93d8f88SEric Biggers } 361c93d8f88SEric Biggers 362fd39073dSEric Biggers static struct page *ext4_read_merkle_tree_page(struct inode *inode, 363fd39073dSEric Biggers pgoff_t index, 364fd39073dSEric Biggers unsigned long num_ra_pages) 365fd39073dSEric Biggers { 366fd39073dSEric Biggers struct page *page; 367fd39073dSEric Biggers 368c93d8f88SEric Biggers index += ext4_verity_metadata_pos(inode) >> PAGE_SHIFT; 369c93d8f88SEric Biggers 370fd39073dSEric Biggers page = find_get_page_flags(inode->i_mapping, index, FGP_ACCESSED); 371fd39073dSEric Biggers if (!page || !PageUptodate(page)) { 3724fa0e3ffSMatthew Wilcox (Oracle) DEFINE_READAHEAD(ractl, NULL, NULL, inode->i_mapping, index); 3734fa0e3ffSMatthew Wilcox (Oracle) 374fd39073dSEric Biggers if (page) 375fd39073dSEric Biggers put_page(page); 376fd39073dSEric Biggers else if (num_ra_pages > 1) 37773bb49daSMatthew Wilcox (Oracle) page_cache_ra_unbounded(&ractl, num_ra_pages, 0); 378fd39073dSEric Biggers page = read_mapping_page(inode->i_mapping, index, NULL); 379fd39073dSEric Biggers } 380fd39073dSEric Biggers return page; 381c93d8f88SEric Biggers } 382c93d8f88SEric Biggers 383c93d8f88SEric Biggers static int ext4_write_merkle_tree_block(struct inode *inode, const void *buf, 384c93d8f88SEric Biggers u64 index, int log_blocksize) 385c93d8f88SEric Biggers { 386c93d8f88SEric Biggers loff_t pos = ext4_verity_metadata_pos(inode) + (index << log_blocksize); 387c93d8f88SEric Biggers 388c93d8f88SEric Biggers return pagecache_write(inode, buf, 1 << log_blocksize, pos); 389c93d8f88SEric Biggers } 390c93d8f88SEric Biggers 391c93d8f88SEric Biggers const struct fsverity_operations ext4_verityops = { 392c93d8f88SEric Biggers .begin_enable_verity = ext4_begin_enable_verity, 393c93d8f88SEric Biggers .end_enable_verity = ext4_end_enable_verity, 394c93d8f88SEric Biggers .get_verity_descriptor = ext4_get_verity_descriptor, 395c93d8f88SEric Biggers .read_merkle_tree_page = ext4_read_merkle_tree_page, 396c93d8f88SEric Biggers .write_merkle_tree_block = ext4_write_merkle_tree_block, 397c93d8f88SEric Biggers }; 398