11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * index.c - NTFS kernel index handling. Part of the Linux-NTFS project. 31da177e4SLinus Torvalds * 4442d207eSAnton Altaparmakov * Copyright (c) 2004-2005 Anton Altaparmakov 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * This program/include file is free software; you can redistribute it and/or 71da177e4SLinus Torvalds * modify it under the terms of the GNU General Public License as published 81da177e4SLinus Torvalds * by the Free Software Foundation; either version 2 of the License, or 91da177e4SLinus Torvalds * (at your option) any later version. 101da177e4SLinus Torvalds * 111da177e4SLinus Torvalds * This program/include file is distributed in the hope that it will be 121da177e4SLinus Torvalds * useful, but WITHOUT ANY WARRANTY; without even the implied warranty 131da177e4SLinus Torvalds * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 141da177e4SLinus Torvalds * GNU General Public License for more details. 151da177e4SLinus Torvalds * 161da177e4SLinus Torvalds * You should have received a copy of the GNU General Public License 171da177e4SLinus Torvalds * along with this program (in the main directory of the Linux-NTFS 181da177e4SLinus Torvalds * distribution in the file COPYING); if not, write to the Free Software 191da177e4SLinus Torvalds * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 201da177e4SLinus Torvalds */ 211da177e4SLinus Torvalds 225a0e3ad6STejun Heo #include <linux/slab.h> 235a0e3ad6STejun Heo 241da177e4SLinus Torvalds #include "aops.h" 251da177e4SLinus Torvalds #include "collate.h" 261da177e4SLinus Torvalds #include "debug.h" 271da177e4SLinus Torvalds #include "index.h" 281da177e4SLinus Torvalds #include "ntfs.h" 291da177e4SLinus Torvalds 301da177e4SLinus Torvalds /** 311da177e4SLinus Torvalds * ntfs_index_ctx_get - allocate and initialize a new index context 321da177e4SLinus Torvalds * @idx_ni: ntfs index inode with which to initialize the context 331da177e4SLinus Torvalds * 341da177e4SLinus Torvalds * Allocate a new index context, initialize it with @idx_ni and return it. 351da177e4SLinus Torvalds * Return NULL if allocation failed. 361da177e4SLinus Torvalds * 371b1dcc1bSJes Sorensen * Locking: Caller must hold i_mutex on the index inode. 381da177e4SLinus Torvalds */ 391da177e4SLinus Torvalds ntfs_index_context *ntfs_index_ctx_get(ntfs_inode *idx_ni) 401da177e4SLinus Torvalds { 411da177e4SLinus Torvalds ntfs_index_context *ictx; 421da177e4SLinus Torvalds 43e6b4f8daSChristoph Lameter ictx = kmem_cache_alloc(ntfs_index_ctx_cache, GFP_NOFS); 44442d207eSAnton Altaparmakov if (ictx) 45442d207eSAnton Altaparmakov *ictx = (ntfs_index_context){ .idx_ni = idx_ni }; 461da177e4SLinus Torvalds return ictx; 471da177e4SLinus Torvalds } 481da177e4SLinus Torvalds 491da177e4SLinus Torvalds /** 501da177e4SLinus Torvalds * ntfs_index_ctx_put - release an index context 511da177e4SLinus Torvalds * @ictx: index context to free 521da177e4SLinus Torvalds * 531da177e4SLinus Torvalds * Release the index context @ictx, releasing all associated resources. 541da177e4SLinus Torvalds * 551b1dcc1bSJes Sorensen * Locking: Caller must hold i_mutex on the index inode. 561da177e4SLinus Torvalds */ 571da177e4SLinus Torvalds void ntfs_index_ctx_put(ntfs_index_context *ictx) 581da177e4SLinus Torvalds { 591da177e4SLinus Torvalds if (ictx->entry) { 601da177e4SLinus Torvalds if (ictx->is_in_root) { 611da177e4SLinus Torvalds if (ictx->actx) 621da177e4SLinus Torvalds ntfs_attr_put_search_ctx(ictx->actx); 631da177e4SLinus Torvalds if (ictx->base_ni) 641da177e4SLinus Torvalds unmap_mft_record(ictx->base_ni); 651da177e4SLinus Torvalds } else { 661da177e4SLinus Torvalds struct page *page = ictx->page; 671da177e4SLinus Torvalds if (page) { 681da177e4SLinus Torvalds BUG_ON(!PageLocked(page)); 691da177e4SLinus Torvalds unlock_page(page); 701da177e4SLinus Torvalds ntfs_unmap_page(page); 711da177e4SLinus Torvalds } 721da177e4SLinus Torvalds } 731da177e4SLinus Torvalds } 741da177e4SLinus Torvalds kmem_cache_free(ntfs_index_ctx_cache, ictx); 751da177e4SLinus Torvalds return; 761da177e4SLinus Torvalds } 771da177e4SLinus Torvalds 781da177e4SLinus Torvalds /** 791da177e4SLinus Torvalds * ntfs_index_lookup - find a key in an index and return its index entry 801da177e4SLinus Torvalds * @key: [IN] key for which to search in the index 811da177e4SLinus Torvalds * @key_len: [IN] length of @key in bytes 821da177e4SLinus Torvalds * @ictx: [IN/OUT] context describing the index and the returned entry 831da177e4SLinus Torvalds * 841da177e4SLinus Torvalds * Before calling ntfs_index_lookup(), @ictx must have been obtained from a 851da177e4SLinus Torvalds * call to ntfs_index_ctx_get(). 861da177e4SLinus Torvalds * 871da177e4SLinus Torvalds * Look for the @key in the index specified by the index lookup context @ictx. 881da177e4SLinus Torvalds * ntfs_index_lookup() walks the contents of the index looking for the @key. 891da177e4SLinus Torvalds * 901da177e4SLinus Torvalds * If the @key is found in the index, 0 is returned and @ictx is setup to 911da177e4SLinus Torvalds * describe the index entry containing the matching @key. @ictx->entry is the 921da177e4SLinus Torvalds * index entry and @ictx->data and @ictx->data_len are the index entry data and 931da177e4SLinus Torvalds * its length in bytes, respectively. 941da177e4SLinus Torvalds * 951da177e4SLinus Torvalds * If the @key is not found in the index, -ENOENT is returned and @ictx is 961da177e4SLinus Torvalds * setup to describe the index entry whose key collates immediately after the 971da177e4SLinus Torvalds * search @key, i.e. this is the position in the index at which an index entry 981da177e4SLinus Torvalds * with a key of @key would need to be inserted. 991da177e4SLinus Torvalds * 1001da177e4SLinus Torvalds * If an error occurs return the negative error code and @ictx is left 1011da177e4SLinus Torvalds * untouched. 1021da177e4SLinus Torvalds * 1031da177e4SLinus Torvalds * When finished with the entry and its data, call ntfs_index_ctx_put() to free 1041da177e4SLinus Torvalds * the context and other associated resources. 1051da177e4SLinus Torvalds * 1061da177e4SLinus Torvalds * If the index entry was modified, call flush_dcache_index_entry_page() 1071da177e4SLinus Torvalds * immediately after the modification and either ntfs_index_entry_mark_dirty() 1081da177e4SLinus Torvalds * or ntfs_index_entry_write() before the call to ntfs_index_ctx_put() to 1091da177e4SLinus Torvalds * ensure that the changes are written to disk. 1101da177e4SLinus Torvalds * 1111b1dcc1bSJes Sorensen * Locking: - Caller must hold i_mutex on the index inode. 1121da177e4SLinus Torvalds * - Each page cache page in the index allocation mapping must be 1131da177e4SLinus Torvalds * locked whilst being accessed otherwise we may find a corrupt 1141da177e4SLinus Torvalds * page due to it being under ->writepage at the moment which 1151da177e4SLinus Torvalds * applies the mst protection fixups before writing out and then 1161da177e4SLinus Torvalds * removes them again after the write is complete after which it 1171da177e4SLinus Torvalds * unlocks the page. 1181da177e4SLinus Torvalds */ 1191da177e4SLinus Torvalds int ntfs_index_lookup(const void *key, const int key_len, 1201da177e4SLinus Torvalds ntfs_index_context *ictx) 1211da177e4SLinus Torvalds { 1221da177e4SLinus Torvalds VCN vcn, old_vcn; 1231da177e4SLinus Torvalds ntfs_inode *idx_ni = ictx->idx_ni; 1241da177e4SLinus Torvalds ntfs_volume *vol = idx_ni->vol; 1251da177e4SLinus Torvalds struct super_block *sb = vol->sb; 1261da177e4SLinus Torvalds ntfs_inode *base_ni = idx_ni->ext.base_ntfs_ino; 1271da177e4SLinus Torvalds MFT_RECORD *m; 1281da177e4SLinus Torvalds INDEX_ROOT *ir; 1291da177e4SLinus Torvalds INDEX_ENTRY *ie; 1301da177e4SLinus Torvalds INDEX_ALLOCATION *ia; 1311da177e4SLinus Torvalds u8 *index_end, *kaddr; 1321da177e4SLinus Torvalds ntfs_attr_search_ctx *actx; 1331da177e4SLinus Torvalds struct address_space *ia_mapping; 1341da177e4SLinus Torvalds struct page *page; 1351da177e4SLinus Torvalds int rc, err = 0; 1361da177e4SLinus Torvalds 1371da177e4SLinus Torvalds ntfs_debug("Entering."); 1381da177e4SLinus Torvalds BUG_ON(!NInoAttr(idx_ni)); 1391da177e4SLinus Torvalds BUG_ON(idx_ni->type != AT_INDEX_ALLOCATION); 1401da177e4SLinus Torvalds BUG_ON(idx_ni->nr_extents != -1); 1411da177e4SLinus Torvalds BUG_ON(!base_ni); 1421da177e4SLinus Torvalds BUG_ON(!key); 1431da177e4SLinus Torvalds BUG_ON(key_len <= 0); 1441da177e4SLinus Torvalds if (!ntfs_is_collation_rule_supported( 1451da177e4SLinus Torvalds idx_ni->itype.index.collation_rule)) { 1461da177e4SLinus Torvalds ntfs_error(sb, "Index uses unsupported collation rule 0x%x. " 1471da177e4SLinus Torvalds "Aborting lookup.", le32_to_cpu( 1481da177e4SLinus Torvalds idx_ni->itype.index.collation_rule)); 1491da177e4SLinus Torvalds return -EOPNOTSUPP; 1501da177e4SLinus Torvalds } 1511da177e4SLinus Torvalds /* Get hold of the mft record for the index inode. */ 1521da177e4SLinus Torvalds m = map_mft_record(base_ni); 1531da177e4SLinus Torvalds if (IS_ERR(m)) { 1541da177e4SLinus Torvalds ntfs_error(sb, "map_mft_record() failed with error code %ld.", 1551da177e4SLinus Torvalds -PTR_ERR(m)); 1561da177e4SLinus Torvalds return PTR_ERR(m); 1571da177e4SLinus Torvalds } 1581da177e4SLinus Torvalds actx = ntfs_attr_get_search_ctx(base_ni, m); 1591da177e4SLinus Torvalds if (unlikely(!actx)) { 1601da177e4SLinus Torvalds err = -ENOMEM; 1611da177e4SLinus Torvalds goto err_out; 1621da177e4SLinus Torvalds } 1631da177e4SLinus Torvalds /* Find the index root attribute in the mft record. */ 1641da177e4SLinus Torvalds err = ntfs_attr_lookup(AT_INDEX_ROOT, idx_ni->name, idx_ni->name_len, 1651da177e4SLinus Torvalds CASE_SENSITIVE, 0, NULL, 0, actx); 1661da177e4SLinus Torvalds if (unlikely(err)) { 1671da177e4SLinus Torvalds if (err == -ENOENT) { 1681da177e4SLinus Torvalds ntfs_error(sb, "Index root attribute missing in inode " 1691da177e4SLinus Torvalds "0x%lx.", idx_ni->mft_no); 1701da177e4SLinus Torvalds err = -EIO; 1711da177e4SLinus Torvalds } 1721da177e4SLinus Torvalds goto err_out; 1731da177e4SLinus Torvalds } 1741da177e4SLinus Torvalds /* Get to the index root value (it has been verified in read_inode). */ 1751da177e4SLinus Torvalds ir = (INDEX_ROOT*)((u8*)actx->attr + 1761da177e4SLinus Torvalds le16_to_cpu(actx->attr->data.resident.value_offset)); 1771da177e4SLinus Torvalds index_end = (u8*)&ir->index + le32_to_cpu(ir->index.index_length); 1781da177e4SLinus Torvalds /* The first index entry. */ 1791da177e4SLinus Torvalds ie = (INDEX_ENTRY*)((u8*)&ir->index + 1801da177e4SLinus Torvalds le32_to_cpu(ir->index.entries_offset)); 1811da177e4SLinus Torvalds /* 1821da177e4SLinus Torvalds * Loop until we exceed valid memory (corruption case) or until we 1831da177e4SLinus Torvalds * reach the last entry. 1841da177e4SLinus Torvalds */ 1851da177e4SLinus Torvalds for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) { 1861da177e4SLinus Torvalds /* Bounds checks. */ 1871da177e4SLinus Torvalds if ((u8*)ie < (u8*)actx->mrec || (u8*)ie + 1881da177e4SLinus Torvalds sizeof(INDEX_ENTRY_HEADER) > index_end || 1891da177e4SLinus Torvalds (u8*)ie + le16_to_cpu(ie->length) > index_end) 1901da177e4SLinus Torvalds goto idx_err_out; 1911da177e4SLinus Torvalds /* 1921da177e4SLinus Torvalds * The last entry cannot contain a key. It can however contain 1931da177e4SLinus Torvalds * a pointer to a child node in the B+tree so we just break out. 1941da177e4SLinus Torvalds */ 1951da177e4SLinus Torvalds if (ie->flags & INDEX_ENTRY_END) 1961da177e4SLinus Torvalds break; 1971da177e4SLinus Torvalds /* Further bounds checks. */ 1981da177e4SLinus Torvalds if ((u32)sizeof(INDEX_ENTRY_HEADER) + 1991da177e4SLinus Torvalds le16_to_cpu(ie->key_length) > 2001da177e4SLinus Torvalds le16_to_cpu(ie->data.vi.data_offset) || 2011da177e4SLinus Torvalds (u32)le16_to_cpu(ie->data.vi.data_offset) + 2021da177e4SLinus Torvalds le16_to_cpu(ie->data.vi.data_length) > 2031da177e4SLinus Torvalds le16_to_cpu(ie->length)) 2041da177e4SLinus Torvalds goto idx_err_out; 2051da177e4SLinus Torvalds /* If the keys match perfectly, we setup @ictx and return 0. */ 2061da177e4SLinus Torvalds if ((key_len == le16_to_cpu(ie->key_length)) && !memcmp(key, 2071da177e4SLinus Torvalds &ie->key, key_len)) { 2081da177e4SLinus Torvalds ir_done: 209c49c3111SRichard Knutsson ictx->is_in_root = true; 2108e08ceaeSAnton Altaparmakov ictx->ir = ir; 2111da177e4SLinus Torvalds ictx->actx = actx; 2121da177e4SLinus Torvalds ictx->base_ni = base_ni; 2131da177e4SLinus Torvalds ictx->ia = NULL; 2141da177e4SLinus Torvalds ictx->page = NULL; 2151da177e4SLinus Torvalds done: 2161da177e4SLinus Torvalds ictx->entry = ie; 2171da177e4SLinus Torvalds ictx->data = (u8*)ie + 2181da177e4SLinus Torvalds le16_to_cpu(ie->data.vi.data_offset); 2191da177e4SLinus Torvalds ictx->data_len = le16_to_cpu(ie->data.vi.data_length); 2201da177e4SLinus Torvalds ntfs_debug("Done."); 2211da177e4SLinus Torvalds return err; 2221da177e4SLinus Torvalds } 2231da177e4SLinus Torvalds /* 2241da177e4SLinus Torvalds * Not a perfect match, need to do full blown collation so we 2251da177e4SLinus Torvalds * know which way in the B+tree we have to go. 2261da177e4SLinus Torvalds */ 2271da177e4SLinus Torvalds rc = ntfs_collate(vol, idx_ni->itype.index.collation_rule, key, 2281da177e4SLinus Torvalds key_len, &ie->key, le16_to_cpu(ie->key_length)); 2291da177e4SLinus Torvalds /* 2301da177e4SLinus Torvalds * If @key collates before the key of the current entry, there 2311da177e4SLinus Torvalds * is definitely no such key in this index but we might need to 2321da177e4SLinus Torvalds * descend into the B+tree so we just break out of the loop. 2331da177e4SLinus Torvalds */ 2341da177e4SLinus Torvalds if (rc == -1) 2351da177e4SLinus Torvalds break; 2361da177e4SLinus Torvalds /* 2371da177e4SLinus Torvalds * A match should never happen as the memcmp() call should have 2381da177e4SLinus Torvalds * cought it, but we still treat it correctly. 2391da177e4SLinus Torvalds */ 2401da177e4SLinus Torvalds if (!rc) 2411da177e4SLinus Torvalds goto ir_done; 2421da177e4SLinus Torvalds /* The keys are not equal, continue the search. */ 2431da177e4SLinus Torvalds } 2441da177e4SLinus Torvalds /* 2451da177e4SLinus Torvalds * We have finished with this index without success. Check for the 2461da177e4SLinus Torvalds * presence of a child node and if not present setup @ictx and return 2471da177e4SLinus Torvalds * -ENOENT. 2481da177e4SLinus Torvalds */ 2491da177e4SLinus Torvalds if (!(ie->flags & INDEX_ENTRY_NODE)) { 2501da177e4SLinus Torvalds ntfs_debug("Entry not found."); 2511da177e4SLinus Torvalds err = -ENOENT; 2521da177e4SLinus Torvalds goto ir_done; 2531da177e4SLinus Torvalds } /* Child node present, descend into it. */ 2541da177e4SLinus Torvalds /* Consistency check: Verify that an index allocation exists. */ 2551da177e4SLinus Torvalds if (!NInoIndexAllocPresent(idx_ni)) { 2561da177e4SLinus Torvalds ntfs_error(sb, "No index allocation attribute but index entry " 2571da177e4SLinus Torvalds "requires one. Inode 0x%lx is corrupt or " 2581da177e4SLinus Torvalds "driver bug.", idx_ni->mft_no); 2591da177e4SLinus Torvalds goto err_out; 2601da177e4SLinus Torvalds } 2611da177e4SLinus Torvalds /* Get the starting vcn of the index_block holding the child node. */ 2621da177e4SLinus Torvalds vcn = sle64_to_cpup((sle64*)((u8*)ie + le16_to_cpu(ie->length) - 8)); 2631da177e4SLinus Torvalds ia_mapping = VFS_I(idx_ni)->i_mapping; 2641da177e4SLinus Torvalds /* 2651da177e4SLinus Torvalds * We are done with the index root and the mft record. Release them, 2661da177e4SLinus Torvalds * otherwise we deadlock with ntfs_map_page(). 2671da177e4SLinus Torvalds */ 2681da177e4SLinus Torvalds ntfs_attr_put_search_ctx(actx); 2691da177e4SLinus Torvalds unmap_mft_record(base_ni); 2701da177e4SLinus Torvalds m = NULL; 2711da177e4SLinus Torvalds actx = NULL; 2721da177e4SLinus Torvalds descend_into_child_node: 2731da177e4SLinus Torvalds /* 2741da177e4SLinus Torvalds * Convert vcn to index into the index allocation attribute in units 2751da177e4SLinus Torvalds * of PAGE_CACHE_SIZE and map the page cache page, reading it from 2761da177e4SLinus Torvalds * disk if necessary. 2771da177e4SLinus Torvalds */ 2781da177e4SLinus Torvalds page = ntfs_map_page(ia_mapping, vcn << 27909cbfeafSKirill A. Shutemov idx_ni->itype.index.vcn_size_bits >> PAGE_SHIFT); 2801da177e4SLinus Torvalds if (IS_ERR(page)) { 2811da177e4SLinus Torvalds ntfs_error(sb, "Failed to map index page, error %ld.", 2821da177e4SLinus Torvalds -PTR_ERR(page)); 2831da177e4SLinus Torvalds err = PTR_ERR(page); 2841da177e4SLinus Torvalds goto err_out; 2851da177e4SLinus Torvalds } 2861da177e4SLinus Torvalds lock_page(page); 2871da177e4SLinus Torvalds kaddr = (u8*)page_address(page); 2881da177e4SLinus Torvalds fast_descend_into_child_node: 2891da177e4SLinus Torvalds /* Get to the index allocation block. */ 2901da177e4SLinus Torvalds ia = (INDEX_ALLOCATION*)(kaddr + ((vcn << 29109cbfeafSKirill A. Shutemov idx_ni->itype.index.vcn_size_bits) & ~PAGE_MASK)); 2921da177e4SLinus Torvalds /* Bounds checks. */ 29309cbfeafSKirill A. Shutemov if ((u8*)ia < kaddr || (u8*)ia > kaddr + PAGE_SIZE) { 2941da177e4SLinus Torvalds ntfs_error(sb, "Out of bounds check failed. Corrupt inode " 2951da177e4SLinus Torvalds "0x%lx or driver bug.", idx_ni->mft_no); 2961da177e4SLinus Torvalds goto unm_err_out; 2971da177e4SLinus Torvalds } 2981da177e4SLinus Torvalds /* Catch multi sector transfer fixup errors. */ 2991da177e4SLinus Torvalds if (unlikely(!ntfs_is_indx_record(ia->magic))) { 3001da177e4SLinus Torvalds ntfs_error(sb, "Index record with vcn 0x%llx is corrupt. " 3011da177e4SLinus Torvalds "Corrupt inode 0x%lx. Run chkdsk.", 3021da177e4SLinus Torvalds (long long)vcn, idx_ni->mft_no); 3031da177e4SLinus Torvalds goto unm_err_out; 3041da177e4SLinus Torvalds } 3051da177e4SLinus Torvalds if (sle64_to_cpu(ia->index_block_vcn) != vcn) { 3061da177e4SLinus Torvalds ntfs_error(sb, "Actual VCN (0x%llx) of index buffer is " 3071da177e4SLinus Torvalds "different from expected VCN (0x%llx). Inode " 3081da177e4SLinus Torvalds "0x%lx is corrupt or driver bug.", 3091da177e4SLinus Torvalds (unsigned long long) 3101da177e4SLinus Torvalds sle64_to_cpu(ia->index_block_vcn), 3111da177e4SLinus Torvalds (unsigned long long)vcn, idx_ni->mft_no); 3121da177e4SLinus Torvalds goto unm_err_out; 3131da177e4SLinus Torvalds } 3141da177e4SLinus Torvalds if (le32_to_cpu(ia->index.allocated_size) + 0x18 != 3151da177e4SLinus Torvalds idx_ni->itype.index.block_size) { 3161da177e4SLinus Torvalds ntfs_error(sb, "Index buffer (VCN 0x%llx) of inode 0x%lx has " 3171da177e4SLinus Torvalds "a size (%u) differing from the index " 3181da177e4SLinus Torvalds "specified size (%u). Inode is corrupt or " 3191da177e4SLinus Torvalds "driver bug.", (unsigned long long)vcn, 3201da177e4SLinus Torvalds idx_ni->mft_no, 3211da177e4SLinus Torvalds le32_to_cpu(ia->index.allocated_size) + 0x18, 3221da177e4SLinus Torvalds idx_ni->itype.index.block_size); 3231da177e4SLinus Torvalds goto unm_err_out; 3241da177e4SLinus Torvalds } 3251da177e4SLinus Torvalds index_end = (u8*)ia + idx_ni->itype.index.block_size; 32609cbfeafSKirill A. Shutemov if (index_end > kaddr + PAGE_SIZE) { 3271da177e4SLinus Torvalds ntfs_error(sb, "Index buffer (VCN 0x%llx) of inode 0x%lx " 3281da177e4SLinus Torvalds "crosses page boundary. Impossible! Cannot " 3291da177e4SLinus Torvalds "access! This is probably a bug in the " 3301da177e4SLinus Torvalds "driver.", (unsigned long long)vcn, 3311da177e4SLinus Torvalds idx_ni->mft_no); 3321da177e4SLinus Torvalds goto unm_err_out; 3331da177e4SLinus Torvalds } 3341da177e4SLinus Torvalds index_end = (u8*)&ia->index + le32_to_cpu(ia->index.index_length); 3351da177e4SLinus Torvalds if (index_end > (u8*)ia + idx_ni->itype.index.block_size) { 3361da177e4SLinus Torvalds ntfs_error(sb, "Size of index buffer (VCN 0x%llx) of inode " 3371da177e4SLinus Torvalds "0x%lx exceeds maximum size.", 3381da177e4SLinus Torvalds (unsigned long long)vcn, idx_ni->mft_no); 3391da177e4SLinus Torvalds goto unm_err_out; 3401da177e4SLinus Torvalds } 3411da177e4SLinus Torvalds /* The first index entry. */ 3421da177e4SLinus Torvalds ie = (INDEX_ENTRY*)((u8*)&ia->index + 3431da177e4SLinus Torvalds le32_to_cpu(ia->index.entries_offset)); 3441da177e4SLinus Torvalds /* 3451da177e4SLinus Torvalds * Iterate similar to above big loop but applied to index buffer, thus 3461da177e4SLinus Torvalds * loop until we exceed valid memory (corruption case) or until we 3471da177e4SLinus Torvalds * reach the last entry. 3481da177e4SLinus Torvalds */ 3491da177e4SLinus Torvalds for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) { 3501da177e4SLinus Torvalds /* Bounds checks. */ 3511da177e4SLinus Torvalds if ((u8*)ie < (u8*)ia || (u8*)ie + 3521da177e4SLinus Torvalds sizeof(INDEX_ENTRY_HEADER) > index_end || 3531da177e4SLinus Torvalds (u8*)ie + le16_to_cpu(ie->length) > index_end) { 3541da177e4SLinus Torvalds ntfs_error(sb, "Index entry out of bounds in inode " 3551da177e4SLinus Torvalds "0x%lx.", idx_ni->mft_no); 3561da177e4SLinus Torvalds goto unm_err_out; 3571da177e4SLinus Torvalds } 3581da177e4SLinus Torvalds /* 3591da177e4SLinus Torvalds * The last entry cannot contain a key. It can however contain 3601da177e4SLinus Torvalds * a pointer to a child node in the B+tree so we just break out. 3611da177e4SLinus Torvalds */ 3621da177e4SLinus Torvalds if (ie->flags & INDEX_ENTRY_END) 3631da177e4SLinus Torvalds break; 3641da177e4SLinus Torvalds /* Further bounds checks. */ 3651da177e4SLinus Torvalds if ((u32)sizeof(INDEX_ENTRY_HEADER) + 3661da177e4SLinus Torvalds le16_to_cpu(ie->key_length) > 3671da177e4SLinus Torvalds le16_to_cpu(ie->data.vi.data_offset) || 3681da177e4SLinus Torvalds (u32)le16_to_cpu(ie->data.vi.data_offset) + 3691da177e4SLinus Torvalds le16_to_cpu(ie->data.vi.data_length) > 3701da177e4SLinus Torvalds le16_to_cpu(ie->length)) { 3711da177e4SLinus Torvalds ntfs_error(sb, "Index entry out of bounds in inode " 3721da177e4SLinus Torvalds "0x%lx.", idx_ni->mft_no); 3731da177e4SLinus Torvalds goto unm_err_out; 3741da177e4SLinus Torvalds } 3751da177e4SLinus Torvalds /* If the keys match perfectly, we setup @ictx and return 0. */ 3761da177e4SLinus Torvalds if ((key_len == le16_to_cpu(ie->key_length)) && !memcmp(key, 3771da177e4SLinus Torvalds &ie->key, key_len)) { 3781da177e4SLinus Torvalds ia_done: 379c49c3111SRichard Knutsson ictx->is_in_root = false; 3801da177e4SLinus Torvalds ictx->actx = NULL; 3811da177e4SLinus Torvalds ictx->base_ni = NULL; 3821da177e4SLinus Torvalds ictx->ia = ia; 3831da177e4SLinus Torvalds ictx->page = page; 3841da177e4SLinus Torvalds goto done; 3851da177e4SLinus Torvalds } 3861da177e4SLinus Torvalds /* 3871da177e4SLinus Torvalds * Not a perfect match, need to do full blown collation so we 3881da177e4SLinus Torvalds * know which way in the B+tree we have to go. 3891da177e4SLinus Torvalds */ 3901da177e4SLinus Torvalds rc = ntfs_collate(vol, idx_ni->itype.index.collation_rule, key, 3911da177e4SLinus Torvalds key_len, &ie->key, le16_to_cpu(ie->key_length)); 3921da177e4SLinus Torvalds /* 3931da177e4SLinus Torvalds * If @key collates before the key of the current entry, there 3941da177e4SLinus Torvalds * is definitely no such key in this index but we might need to 3951da177e4SLinus Torvalds * descend into the B+tree so we just break out of the loop. 3961da177e4SLinus Torvalds */ 3971da177e4SLinus Torvalds if (rc == -1) 3981da177e4SLinus Torvalds break; 3991da177e4SLinus Torvalds /* 4001da177e4SLinus Torvalds * A match should never happen as the memcmp() call should have 4011da177e4SLinus Torvalds * cought it, but we still treat it correctly. 4021da177e4SLinus Torvalds */ 4031da177e4SLinus Torvalds if (!rc) 4041da177e4SLinus Torvalds goto ia_done; 4051da177e4SLinus Torvalds /* The keys are not equal, continue the search. */ 4061da177e4SLinus Torvalds } 4071da177e4SLinus Torvalds /* 4081da177e4SLinus Torvalds * We have finished with this index buffer without success. Check for 4091da177e4SLinus Torvalds * the presence of a child node and if not present return -ENOENT. 4101da177e4SLinus Torvalds */ 4111da177e4SLinus Torvalds if (!(ie->flags & INDEX_ENTRY_NODE)) { 4121da177e4SLinus Torvalds ntfs_debug("Entry not found."); 4131da177e4SLinus Torvalds err = -ENOENT; 4141da177e4SLinus Torvalds goto ia_done; 4151da177e4SLinus Torvalds } 4161da177e4SLinus Torvalds if ((ia->index.flags & NODE_MASK) == LEAF_NODE) { 4171da177e4SLinus Torvalds ntfs_error(sb, "Index entry with child node found in a leaf " 4181da177e4SLinus Torvalds "node in inode 0x%lx.", idx_ni->mft_no); 4191da177e4SLinus Torvalds goto unm_err_out; 4201da177e4SLinus Torvalds } 4211da177e4SLinus Torvalds /* Child node present, descend into it. */ 4221da177e4SLinus Torvalds old_vcn = vcn; 4231da177e4SLinus Torvalds vcn = sle64_to_cpup((sle64*)((u8*)ie + le16_to_cpu(ie->length) - 8)); 4241da177e4SLinus Torvalds if (vcn >= 0) { 4251da177e4SLinus Torvalds /* 4261da177e4SLinus Torvalds * If vcn is in the same page cache page as old_vcn we recycle 4271da177e4SLinus Torvalds * the mapped page. 4281da177e4SLinus Torvalds */ 4291da177e4SLinus Torvalds if (old_vcn << vol->cluster_size_bits >> 43009cbfeafSKirill A. Shutemov PAGE_SHIFT == vcn << 4311da177e4SLinus Torvalds vol->cluster_size_bits >> 43209cbfeafSKirill A. Shutemov PAGE_SHIFT) 4331da177e4SLinus Torvalds goto fast_descend_into_child_node; 4341da177e4SLinus Torvalds unlock_page(page); 4351da177e4SLinus Torvalds ntfs_unmap_page(page); 4361da177e4SLinus Torvalds goto descend_into_child_node; 4371da177e4SLinus Torvalds } 4381da177e4SLinus Torvalds ntfs_error(sb, "Negative child node vcn in inode 0x%lx.", 4391da177e4SLinus Torvalds idx_ni->mft_no); 4401da177e4SLinus Torvalds unm_err_out: 4411da177e4SLinus Torvalds unlock_page(page); 4421da177e4SLinus Torvalds ntfs_unmap_page(page); 4431da177e4SLinus Torvalds err_out: 4441da177e4SLinus Torvalds if (!err) 4451da177e4SLinus Torvalds err = -EIO; 4461da177e4SLinus Torvalds if (actx) 4471da177e4SLinus Torvalds ntfs_attr_put_search_ctx(actx); 4481da177e4SLinus Torvalds if (m) 4491da177e4SLinus Torvalds unmap_mft_record(base_ni); 4501da177e4SLinus Torvalds return err; 4511da177e4SLinus Torvalds idx_err_out: 4521da177e4SLinus Torvalds ntfs_error(sb, "Corrupt index. Aborting lookup."); 4531da177e4SLinus Torvalds goto err_out; 4541da177e4SLinus Torvalds } 455