+++ /dev/null
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * index.c - NTFS kernel index handling. Part of the Linux-NTFS project.
- *
- * Copyright (c) 2004-2005 Anton Altaparmakov
- */
-
-#include <linux/slab.h>
-
-#include "aops.h"
-#include "collate.h"
-#include "debug.h"
-#include "index.h"
-#include "ntfs.h"
-
-/**
- * ntfs_index_ctx_get - allocate and initialize a new index context
- * @idx_ni: ntfs index inode with which to initialize the context
- *
- * Allocate a new index context, initialize it with @idx_ni and return it.
- * Return NULL if allocation failed.
- *
- * Locking: Caller must hold i_mutex on the index inode.
- */
-ntfs_index_context *ntfs_index_ctx_get(ntfs_inode *idx_ni)
-{
- ntfs_index_context *ictx;
-
- ictx = kmem_cache_alloc(ntfs_index_ctx_cache, GFP_NOFS);
- if (ictx)
- *ictx = (ntfs_index_context){ .idx_ni = idx_ni };
- return ictx;
-}
-
-/**
- * ntfs_index_ctx_put - release an index context
- * @ictx: index context to free
- *
- * Release the index context @ictx, releasing all associated resources.
- *
- * Locking: Caller must hold i_mutex on the index inode.
- */
-void ntfs_index_ctx_put(ntfs_index_context *ictx)
-{
- if (ictx->entry) {
- if (ictx->is_in_root) {
- if (ictx->actx)
- ntfs_attr_put_search_ctx(ictx->actx);
- if (ictx->base_ni)
- unmap_mft_record(ictx->base_ni);
- } else {
- struct page *page = ictx->page;
- if (page) {
- BUG_ON(!PageLocked(page));
- unlock_page(page);
- ntfs_unmap_page(page);
- }
- }
- }
- kmem_cache_free(ntfs_index_ctx_cache, ictx);
- return;
-}
-
-/**
- * ntfs_index_lookup - find a key in an index and return its index entry
- * @key: [IN] key for which to search in the index
- * @key_len: [IN] length of @key in bytes
- * @ictx: [IN/OUT] context describing the index and the returned entry
- *
- * Before calling ntfs_index_lookup(), @ictx must have been obtained from a
- * call to ntfs_index_ctx_get().
- *
- * Look for the @key in the index specified by the index lookup context @ictx.
- * ntfs_index_lookup() walks the contents of the index looking for the @key.
- *
- * If the @key is found in the index, 0 is returned and @ictx is setup to
- * describe the index entry containing the matching @key. @ictx->entry is the
- * index entry and @ictx->data and @ictx->data_len are the index entry data and
- * its length in bytes, respectively.
- *
- * If the @key is not found in the index, -ENOENT is returned and @ictx is
- * setup to describe the index entry whose key collates immediately after the
- * search @key, i.e. this is the position in the index at which an index entry
- * with a key of @key would need to be inserted.
- *
- * If an error occurs return the negative error code and @ictx is left
- * untouched.
- *
- * When finished with the entry and its data, call ntfs_index_ctx_put() to free
- * the context and other associated resources.
- *
- * If the index entry was modified, call flush_dcache_index_entry_page()
- * immediately after the modification and either ntfs_index_entry_mark_dirty()
- * or ntfs_index_entry_write() before the call to ntfs_index_ctx_put() to
- * ensure that the changes are written to disk.
- *
- * Locking: - Caller must hold i_mutex on the index inode.
- * - Each page cache page in the index allocation mapping must be
- * locked whilst being accessed otherwise we may find a corrupt
- * page due to it being under ->writepage at the moment which
- * applies the mst protection fixups before writing out and then
- * removes them again after the write is complete after which it
- * unlocks the page.
- */
-int ntfs_index_lookup(const void *key, const int key_len,
- ntfs_index_context *ictx)
-{
- VCN vcn, old_vcn;
- ntfs_inode *idx_ni = ictx->idx_ni;
- ntfs_volume *vol = idx_ni->vol;
- struct super_block *sb = vol->sb;
- ntfs_inode *base_ni = idx_ni->ext.base_ntfs_ino;
- MFT_RECORD *m;
- INDEX_ROOT *ir;
- INDEX_ENTRY *ie;
- INDEX_ALLOCATION *ia;
- u8 *index_end, *kaddr;
- ntfs_attr_search_ctx *actx;
- struct address_space *ia_mapping;
- struct page *page;
- int rc, err = 0;
-
- ntfs_debug("Entering.");
- BUG_ON(!NInoAttr(idx_ni));
- BUG_ON(idx_ni->type != AT_INDEX_ALLOCATION);
- BUG_ON(idx_ni->nr_extents != -1);
- BUG_ON(!base_ni);
- BUG_ON(!key);
- BUG_ON(key_len <= 0);
- if (!ntfs_is_collation_rule_supported(
- idx_ni->itype.index.collation_rule)) {
- ntfs_error(sb, "Index uses unsupported collation rule 0x%x. "
- "Aborting lookup.", le32_to_cpu(
- idx_ni->itype.index.collation_rule));
- return -EOPNOTSUPP;
- }
- /* Get hold of the mft record for the index inode. */
- m = map_mft_record(base_ni);
- if (IS_ERR(m)) {
- ntfs_error(sb, "map_mft_record() failed with error code %ld.",
- -PTR_ERR(m));
- return PTR_ERR(m);
- }
- actx = ntfs_attr_get_search_ctx(base_ni, m);
- if (unlikely(!actx)) {
- err = -ENOMEM;
- goto err_out;
- }
- /* Find the index root attribute in the mft record. */
- err = ntfs_attr_lookup(AT_INDEX_ROOT, idx_ni->name, idx_ni->name_len,
- CASE_SENSITIVE, 0, NULL, 0, actx);
- if (unlikely(err)) {
- if (err == -ENOENT) {
- ntfs_error(sb, "Index root attribute missing in inode "
- "0x%lx.", idx_ni->mft_no);
- err = -EIO;
- }
- goto err_out;
- }
- /* Get to the index root value (it has been verified in read_inode). */
- ir = (INDEX_ROOT*)((u8*)actx->attr +
- le16_to_cpu(actx->attr->data.resident.value_offset));
- index_end = (u8*)&ir->index + le32_to_cpu(ir->index.index_length);
- /* The first index entry. */
- ie = (INDEX_ENTRY*)((u8*)&ir->index +
- le32_to_cpu(ir->index.entries_offset));
- /*
- * Loop until we exceed valid memory (corruption case) or until we
- * reach the last entry.
- */
- for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
- /* Bounds checks. */
- if ((u8*)ie < (u8*)actx->mrec || (u8*)ie +
- sizeof(INDEX_ENTRY_HEADER) > index_end ||
- (u8*)ie + le16_to_cpu(ie->length) > index_end)
- goto idx_err_out;
- /*
- * The last entry cannot contain a key. It can however contain
- * a pointer to a child node in the B+tree so we just break out.
- */
- if (ie->flags & INDEX_ENTRY_END)
- break;
- /* Further bounds checks. */
- if ((u32)sizeof(INDEX_ENTRY_HEADER) +
- le16_to_cpu(ie->key_length) >
- le16_to_cpu(ie->data.vi.data_offset) ||
- (u32)le16_to_cpu(ie->data.vi.data_offset) +
- le16_to_cpu(ie->data.vi.data_length) >
- le16_to_cpu(ie->length))
- goto idx_err_out;
- /* If the keys match perfectly, we setup @ictx and return 0. */
- if ((key_len == le16_to_cpu(ie->key_length)) && !memcmp(key,
- &ie->key, key_len)) {
-ir_done:
- ictx->is_in_root = true;
- ictx->ir = ir;
- ictx->actx = actx;
- ictx->base_ni = base_ni;
- ictx->ia = NULL;
- ictx->page = NULL;
-done:
- ictx->entry = ie;
- ictx->data = (u8*)ie +
- le16_to_cpu(ie->data.vi.data_offset);
- ictx->data_len = le16_to_cpu(ie->data.vi.data_length);
- ntfs_debug("Done.");
- return err;
- }
- /*
- * Not a perfect match, need to do full blown collation so we
- * know which way in the B+tree we have to go.
- */
- rc = ntfs_collate(vol, idx_ni->itype.index.collation_rule, key,
- key_len, &ie->key, le16_to_cpu(ie->key_length));
- /*
- * If @key collates before the key of the current entry, there
- * is definitely no such key in this index but we might need to
- * descend into the B+tree so we just break out of the loop.
- */
- if (rc == -1)
- break;
- /*
- * A match should never happen as the memcmp() call should have
- * cought it, but we still treat it correctly.
- */
- if (!rc)
- goto ir_done;
- /* The keys are not equal, continue the search. */
- }
- /*
- * We have finished with this index without success. Check for the
- * presence of a child node and if not present setup @ictx and return
- * -ENOENT.
- */
- if (!(ie->flags & INDEX_ENTRY_NODE)) {
- ntfs_debug("Entry not found.");
- err = -ENOENT;
- goto ir_done;
- } /* Child node present, descend into it. */
- /* Consistency check: Verify that an index allocation exists. */
- if (!NInoIndexAllocPresent(idx_ni)) {
- ntfs_error(sb, "No index allocation attribute but index entry "
- "requires one. Inode 0x%lx is corrupt or "
- "driver bug.", idx_ni->mft_no);
- goto err_out;
- }
- /* Get the starting vcn of the index_block holding the child node. */
- vcn = sle64_to_cpup((sle64*)((u8*)ie + le16_to_cpu(ie->length) - 8));
- ia_mapping = VFS_I(idx_ni)->i_mapping;
- /*
- * We are done with the index root and the mft record. Release them,
- * otherwise we deadlock with ntfs_map_page().
- */
- ntfs_attr_put_search_ctx(actx);
- unmap_mft_record(base_ni);
- m = NULL;
- actx = NULL;
-descend_into_child_node:
- /*
- * Convert vcn to index into the index allocation attribute in units
- * of PAGE_SIZE and map the page cache page, reading it from
- * disk if necessary.
- */
- page = ntfs_map_page(ia_mapping, vcn <<
- idx_ni->itype.index.vcn_size_bits >> PAGE_SHIFT);
- if (IS_ERR(page)) {
- ntfs_error(sb, "Failed to map index page, error %ld.",
- -PTR_ERR(page));
- err = PTR_ERR(page);
- goto err_out;
- }
- lock_page(page);
- kaddr = (u8*)page_address(page);
-fast_descend_into_child_node:
- /* Get to the index allocation block. */
- ia = (INDEX_ALLOCATION*)(kaddr + ((vcn <<
- idx_ni->itype.index.vcn_size_bits) & ~PAGE_MASK));
- /* Bounds checks. */
- if ((u8*)ia < kaddr || (u8*)ia > kaddr + PAGE_SIZE) {
- ntfs_error(sb, "Out of bounds check failed. Corrupt inode "
- "0x%lx or driver bug.", idx_ni->mft_no);
- goto unm_err_out;
- }
- /* Catch multi sector transfer fixup errors. */
- if (unlikely(!ntfs_is_indx_record(ia->magic))) {
- ntfs_error(sb, "Index record with vcn 0x%llx is corrupt. "
- "Corrupt inode 0x%lx. Run chkdsk.",
- (long long)vcn, idx_ni->mft_no);
- goto unm_err_out;
- }
- if (sle64_to_cpu(ia->index_block_vcn) != vcn) {
- ntfs_error(sb, "Actual VCN (0x%llx) of index buffer is "
- "different from expected VCN (0x%llx). Inode "
- "0x%lx is corrupt or driver bug.",
- (unsigned long long)
- sle64_to_cpu(ia->index_block_vcn),
- (unsigned long long)vcn, idx_ni->mft_no);
- goto unm_err_out;
- }
- if (le32_to_cpu(ia->index.allocated_size) + 0x18 !=
- idx_ni->itype.index.block_size) {
- ntfs_error(sb, "Index buffer (VCN 0x%llx) of inode 0x%lx has "
- "a size (%u) differing from the index "
- "specified size (%u). Inode is corrupt or "
- "driver bug.", (unsigned long long)vcn,
- idx_ni->mft_no,
- le32_to_cpu(ia->index.allocated_size) + 0x18,
- idx_ni->itype.index.block_size);
- goto unm_err_out;
- }
- index_end = (u8*)ia + idx_ni->itype.index.block_size;
- if (index_end > kaddr + PAGE_SIZE) {
- ntfs_error(sb, "Index buffer (VCN 0x%llx) of inode 0x%lx "
- "crosses page boundary. Impossible! Cannot "
- "access! This is probably a bug in the "
- "driver.", (unsigned long long)vcn,
- idx_ni->mft_no);
- goto unm_err_out;
- }
- index_end = (u8*)&ia->index + le32_to_cpu(ia->index.index_length);
- if (index_end > (u8*)ia + idx_ni->itype.index.block_size) {
- ntfs_error(sb, "Size of index buffer (VCN 0x%llx) of inode "
- "0x%lx exceeds maximum size.",
- (unsigned long long)vcn, idx_ni->mft_no);
- goto unm_err_out;
- }
- /* The first index entry. */
- ie = (INDEX_ENTRY*)((u8*)&ia->index +
- le32_to_cpu(ia->index.entries_offset));
- /*
- * Iterate similar to above big loop but applied to index buffer, thus
- * loop until we exceed valid memory (corruption case) or until we
- * reach the last entry.
- */
- for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
- /* Bounds checks. */
- if ((u8*)ie < (u8*)ia || (u8*)ie +
- sizeof(INDEX_ENTRY_HEADER) > index_end ||
- (u8*)ie + le16_to_cpu(ie->length) > index_end) {
- ntfs_error(sb, "Index entry out of bounds in inode "
- "0x%lx.", idx_ni->mft_no);
- goto unm_err_out;
- }
- /*
- * The last entry cannot contain a key. It can however contain
- * a pointer to a child node in the B+tree so we just break out.
- */
- if (ie->flags & INDEX_ENTRY_END)
- break;
- /* Further bounds checks. */
- if ((u32)sizeof(INDEX_ENTRY_HEADER) +
- le16_to_cpu(ie->key_length) >
- le16_to_cpu(ie->data.vi.data_offset) ||
- (u32)le16_to_cpu(ie->data.vi.data_offset) +
- le16_to_cpu(ie->data.vi.data_length) >
- le16_to_cpu(ie->length)) {
- ntfs_error(sb, "Index entry out of bounds in inode "
- "0x%lx.", idx_ni->mft_no);
- goto unm_err_out;
- }
- /* If the keys match perfectly, we setup @ictx and return 0. */
- if ((key_len == le16_to_cpu(ie->key_length)) && !memcmp(key,
- &ie->key, key_len)) {
-ia_done:
- ictx->is_in_root = false;
- ictx->actx = NULL;
- ictx->base_ni = NULL;
- ictx->ia = ia;
- ictx->page = page;
- goto done;
- }
- /*
- * Not a perfect match, need to do full blown collation so we
- * know which way in the B+tree we have to go.
- */
- rc = ntfs_collate(vol, idx_ni->itype.index.collation_rule, key,
- key_len, &ie->key, le16_to_cpu(ie->key_length));
- /*
- * If @key collates before the key of the current entry, there
- * is definitely no such key in this index but we might need to
- * descend into the B+tree so we just break out of the loop.
- */
- if (rc == -1)
- break;
- /*
- * A match should never happen as the memcmp() call should have
- * cought it, but we still treat it correctly.
- */
- if (!rc)
- goto ia_done;
- /* The keys are not equal, continue the search. */
- }
- /*
- * We have finished with this index buffer without success. Check for
- * the presence of a child node and if not present return -ENOENT.
- */
- if (!(ie->flags & INDEX_ENTRY_NODE)) {
- ntfs_debug("Entry not found.");
- err = -ENOENT;
- goto ia_done;
- }
- if ((ia->index.flags & NODE_MASK) == LEAF_NODE) {
- ntfs_error(sb, "Index entry with child node found in a leaf "
- "node in inode 0x%lx.", idx_ni->mft_no);
- goto unm_err_out;
- }
- /* Child node present, descend into it. */
- old_vcn = vcn;
- vcn = sle64_to_cpup((sle64*)((u8*)ie + le16_to_cpu(ie->length) - 8));
- if (vcn >= 0) {
- /*
- * If vcn is in the same page cache page as old_vcn we recycle
- * the mapped page.
- */
- if (old_vcn << vol->cluster_size_bits >>
- PAGE_SHIFT == vcn <<
- vol->cluster_size_bits >>
- PAGE_SHIFT)
- goto fast_descend_into_child_node;
- unlock_page(page);
- ntfs_unmap_page(page);
- goto descend_into_child_node;
- }
- ntfs_error(sb, "Negative child node vcn in inode 0x%lx.",
- idx_ni->mft_no);
-unm_err_out:
- unlock_page(page);
- ntfs_unmap_page(page);
-err_out:
- if (!err)
- err = -EIO;
- if (actx)
- ntfs_attr_put_search_ctx(actx);
- if (m)
- unmap_mft_record(base_ni);
- return err;
-idx_err_out:
- ntfs_error(sb, "Corrupt index. Aborting lookup.");
- goto err_out;
-}
projects / linux-2.6-microblaze.git / blobdiff