455 lines
15 KiB
C
455 lines
15 KiB
C
/*
|
|
* index.c - NTFS kernel index handling. Part of the Linux-NTFS project.
|
|
*
|
|
* Copyright (c) 2004-2005 Anton Altaparmakov
|
|
*
|
|
* This program/include file is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License as published
|
|
* by the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program/include file is distributed in the hope that it will be
|
|
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty
|
|
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program (in the main directory of the Linux-NTFS
|
|
* distribution in the file COPYING); if not, write to the Free Software
|
|
* Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*/
|
|
|
|
#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;
|
|
}
|