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![Anton Altaparmakov](/assets/img/avatar_default.png)
helper ntfs_map_runlist_nolock() which is used by ntfs_map_runlist(). This allows us to map runlist fragments with the runlist lock already held without having to drop and reacquire it around the call. Adapt all callers. - Change ntfs_find_vcn() to ntfs_find_vcn_nolock() which takes a locked runlist. This allows us to find runlist elements with the runlist lock already held without having to drop and reacquire it around the call. Adapt all callers. Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
1279 lines
42 KiB
C
1279 lines
42 KiB
C
/**
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* attrib.c - NTFS attribute operations. Part of the Linux-NTFS project.
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*
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* Copyright (c) 2001-2005 Anton Altaparmakov
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* Copyright (c) 2002 Richard Russon
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*
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* This program/include file is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as published
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* by the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program/include file is distributed in the hope that it will be
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* useful, but WITHOUT ANY WARRANTY; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program (in the main directory of the Linux-NTFS
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* distribution in the file COPYING); if not, write to the Free Software
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* Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/buffer_head.h>
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#include "attrib.h"
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#include "debug.h"
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#include "layout.h"
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#include "mft.h"
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#include "ntfs.h"
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#include "types.h"
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/**
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* ntfs_map_runlist_nolock - map (a part of) a runlist of an ntfs inode
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* @ni: ntfs inode for which to map (part of) a runlist
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* @vcn: map runlist part containing this vcn
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*
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* Map the part of a runlist containing the @vcn of the ntfs inode @ni.
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*
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* Return 0 on success and -errno on error.
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*
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* Locking: - The runlist must be locked for writing.
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* - This function modifies the runlist.
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*/
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int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn)
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{
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ntfs_inode *base_ni;
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MFT_RECORD *mrec;
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ntfs_attr_search_ctx *ctx;
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runlist_element *rl;
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int err = 0;
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ntfs_debug("Mapping runlist part containing vcn 0x%llx.",
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(unsigned long long)vcn);
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if (!NInoAttr(ni))
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base_ni = ni;
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else
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base_ni = ni->ext.base_ntfs_ino;
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mrec = map_mft_record(base_ni);
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if (IS_ERR(mrec))
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return PTR_ERR(mrec);
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ctx = ntfs_attr_get_search_ctx(base_ni, mrec);
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if (unlikely(!ctx)) {
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err = -ENOMEM;
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goto err_out;
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}
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err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
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CASE_SENSITIVE, vcn, NULL, 0, ctx);
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if (likely(!err)) {
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rl = ntfs_mapping_pairs_decompress(ni->vol, ctx->attr,
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ni->runlist.rl);
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if (IS_ERR(rl))
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err = PTR_ERR(rl);
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else
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ni->runlist.rl = rl;
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}
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ntfs_attr_put_search_ctx(ctx);
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err_out:
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unmap_mft_record(base_ni);
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return err;
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}
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/**
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* ntfs_map_runlist - map (a part of) a runlist of an ntfs inode
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* @ni: ntfs inode for which to map (part of) a runlist
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* @vcn: map runlist part containing this vcn
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*
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* Map the part of a runlist containing the @vcn of the ntfs inode @ni.
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*
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* Return 0 on success and -errno on error.
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*
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* Locking: - The runlist must be unlocked on entry and is unlocked on return.
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* - This function takes the runlist lock for writing and modifies the
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* runlist.
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*/
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int ntfs_map_runlist(ntfs_inode *ni, VCN vcn)
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{
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int err = 0;
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down_write(&ni->runlist.lock);
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/* Make sure someone else didn't do the work while we were sleeping. */
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if (likely(ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn) <=
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LCN_RL_NOT_MAPPED))
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err = ntfs_map_runlist_nolock(ni, vcn);
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up_write(&ni->runlist.lock);
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return err;
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}
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/**
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* ntfs_find_vcn_nolock - find a vcn in the runlist described by an ntfs inode
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* @ni: ntfs inode describing the runlist to search
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* @vcn: vcn to find
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* @write_locked: true if the runlist is locked for writing
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*
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* Find the virtual cluster number @vcn in the runlist described by the ntfs
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* inode @ni and return the address of the runlist element containing the @vcn.
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* The runlist is left locked and the caller has to unlock it. In the error
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* case, the runlist is left in the same locking state as on entry.
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*
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* Note if @write_locked is FALSE the lock may be dropped inside the function
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* so you cannot rely on the runlist still being the same when this function
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* returns.
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*
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* Note you need to distinguish between the lcn of the returned runlist element
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* being >= 0 and LCN_HOLE. In the later case you have to return zeroes on
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* read and allocate clusters on write.
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*
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* Return the runlist element containing the @vcn on success and
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* ERR_PTR(-errno) on error. You need to test the return value with IS_ERR()
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* to decide if the return is success or failure and PTR_ERR() to get to the
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* error code if IS_ERR() is true.
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*
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* The possible error return codes are:
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* -ENOENT - No such vcn in the runlist, i.e. @vcn is out of bounds.
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* -ENOMEM - Not enough memory to map runlist.
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* -EIO - Critical error (runlist/file is corrupt, i/o error, etc).
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*
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* Locking: - The runlist must be unlocked on entry.
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* - On failing return, the runlist is unlocked.
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* - On successful return, the runlist is locked. If @need_write us
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* true, it is locked for writing. Otherwise is is locked for
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* reading.
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*/
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runlist_element *ntfs_find_vcn_nolock(ntfs_inode *ni, const VCN vcn,
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const BOOL write_locked)
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{
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runlist_element *rl;
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int err = 0;
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BOOL is_retry = FALSE;
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ntfs_debug("Entering for i_ino 0x%lx, vcn 0x%llx, %s_locked.",
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ni->mft_no, (unsigned long long)vcn,
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write_locked ? "write" : "read");
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BUG_ON(!ni);
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BUG_ON(!NInoNonResident(ni));
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BUG_ON(vcn < 0);
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retry_remap:
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rl = ni->runlist.rl;
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if (likely(rl && vcn >= rl[0].vcn)) {
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while (likely(rl->length)) {
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if (unlikely(vcn < rl[1].vcn)) {
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if (likely(rl->lcn >= LCN_HOLE)) {
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ntfs_debug("Done.");
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return rl;
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}
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break;
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}
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rl++;
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}
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if (likely(rl->lcn != LCN_RL_NOT_MAPPED)) {
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if (likely(rl->lcn == LCN_ENOENT))
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err = -ENOENT;
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else
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err = -EIO;
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}
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}
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if (!err && !is_retry) {
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/*
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* The @vcn is in an unmapped region, map the runlist and
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* retry.
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*/
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if (!write_locked) {
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up_read(&ni->runlist.lock);
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down_write(&ni->runlist.lock);
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}
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err = ntfs_map_runlist_nolock(ni, vcn);
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if (!write_locked) {
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up_write(&ni->runlist.lock);
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down_read(&ni->runlist.lock);
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}
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if (likely(!err)) {
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is_retry = TRUE;
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goto retry_remap;
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}
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/*
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* -EINVAL and -ENOENT coming from a failed mapping attempt are
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* equivalent to i/o errors for us as they should not happen in
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* our code paths.
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*/
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if (err == -EINVAL || err == -ENOENT)
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err = -EIO;
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} else if (!err)
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err = -EIO;
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if (err != -ENOENT)
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ntfs_error(ni->vol->sb, "Failed with error code %i.", err);
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return ERR_PTR(err);
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}
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/**
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* ntfs_attr_find - find (next) attribute in mft record
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* @type: attribute type to find
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* @name: attribute name to find (optional, i.e. NULL means don't care)
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* @name_len: attribute name length (only needed if @name present)
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* @ic: IGNORE_CASE or CASE_SENSITIVE (ignored if @name not present)
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* @val: attribute value to find (optional, resident attributes only)
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* @val_len: attribute value length
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* @ctx: search context with mft record and attribute to search from
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*
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* You should not need to call this function directly. Use ntfs_attr_lookup()
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* instead.
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*
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* ntfs_attr_find() takes a search context @ctx as parameter and searches the
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* mft record specified by @ctx->mrec, beginning at @ctx->attr, for an
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* attribute of @type, optionally @name and @val.
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*
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* If the attribute is found, ntfs_attr_find() returns 0 and @ctx->attr will
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* point to the found attribute.
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*
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* If the attribute is not found, ntfs_attr_find() returns -ENOENT and
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* @ctx->attr will point to the attribute before which the attribute being
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* searched for would need to be inserted if such an action were to be desired.
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*
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* On actual error, ntfs_attr_find() returns -EIO. In this case @ctx->attr is
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* undefined and in particular do not rely on it not changing.
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*
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* If @ctx->is_first is TRUE, the search begins with @ctx->attr itself. If it
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* is FALSE, the search begins after @ctx->attr.
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*
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* If @ic is IGNORE_CASE, the @name comparisson is not case sensitive and
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* @ctx->ntfs_ino must be set to the ntfs inode to which the mft record
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* @ctx->mrec belongs. This is so we can get at the ntfs volume and hence at
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* the upcase table. If @ic is CASE_SENSITIVE, the comparison is case
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* sensitive. When @name is present, @name_len is the @name length in Unicode
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* characters.
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*
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* If @name is not present (NULL), we assume that the unnamed attribute is
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* being searched for.
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*
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* Finally, the resident attribute value @val is looked for, if present. If
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* @val is not present (NULL), @val_len is ignored.
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*
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* ntfs_attr_find() only searches the specified mft record and it ignores the
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* presence of an attribute list attribute (unless it is the one being searched
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* for, obviously). If you need to take attribute lists into consideration,
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* use ntfs_attr_lookup() instead (see below). This also means that you cannot
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* use ntfs_attr_find() to search for extent records of non-resident
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* attributes, as extents with lowest_vcn != 0 are usually described by the
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* attribute list attribute only. - Note that it is possible that the first
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* extent is only in the attribute list while the last extent is in the base
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* mft record, so do not rely on being able to find the first extent in the
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* base mft record.
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*
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* Warning: Never use @val when looking for attribute types which can be
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* non-resident as this most likely will result in a crash!
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*/
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static int ntfs_attr_find(const ATTR_TYPE type, const ntfschar *name,
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const u32 name_len, const IGNORE_CASE_BOOL ic,
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const u8 *val, const u32 val_len, ntfs_attr_search_ctx *ctx)
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{
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ATTR_RECORD *a;
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ntfs_volume *vol = ctx->ntfs_ino->vol;
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ntfschar *upcase = vol->upcase;
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u32 upcase_len = vol->upcase_len;
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/*
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* Iterate over attributes in mft record starting at @ctx->attr, or the
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* attribute following that, if @ctx->is_first is TRUE.
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*/
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if (ctx->is_first) {
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a = ctx->attr;
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ctx->is_first = FALSE;
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} else
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a = (ATTR_RECORD*)((u8*)ctx->attr +
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le32_to_cpu(ctx->attr->length));
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for (;; a = (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length))) {
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if ((u8*)a < (u8*)ctx->mrec || (u8*)a > (u8*)ctx->mrec +
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le32_to_cpu(ctx->mrec->bytes_allocated))
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break;
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ctx->attr = a;
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if (unlikely(le32_to_cpu(a->type) > le32_to_cpu(type) ||
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a->type == AT_END))
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return -ENOENT;
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if (unlikely(!a->length))
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break;
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if (a->type != type)
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continue;
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/*
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* If @name is present, compare the two names. If @name is
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* missing, assume we want an unnamed attribute.
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*/
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if (!name) {
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/* The search failed if the found attribute is named. */
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if (a->name_length)
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return -ENOENT;
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} else if (!ntfs_are_names_equal(name, name_len,
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(ntfschar*)((u8*)a + le16_to_cpu(a->name_offset)),
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a->name_length, ic, upcase, upcase_len)) {
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register int rc;
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rc = ntfs_collate_names(name, name_len,
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(ntfschar*)((u8*)a +
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le16_to_cpu(a->name_offset)),
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a->name_length, 1, IGNORE_CASE,
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upcase, upcase_len);
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/*
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* If @name collates before a->name, there is no
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* matching attribute.
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*/
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if (rc == -1)
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return -ENOENT;
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/* If the strings are not equal, continue search. */
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if (rc)
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continue;
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rc = ntfs_collate_names(name, name_len,
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(ntfschar*)((u8*)a +
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le16_to_cpu(a->name_offset)),
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a->name_length, 1, CASE_SENSITIVE,
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upcase, upcase_len);
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if (rc == -1)
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return -ENOENT;
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if (rc)
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continue;
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}
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/*
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* The names match or @name not present and attribute is
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* unnamed. If no @val specified, we have found the attribute
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* and are done.
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*/
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if (!val)
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return 0;
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/* @val is present; compare values. */
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else {
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register int rc;
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rc = memcmp(val, (u8*)a + le16_to_cpu(
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a->data.resident.value_offset),
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min_t(u32, val_len, le32_to_cpu(
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a->data.resident.value_length)));
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/*
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* If @val collates before the current attribute's
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* value, there is no matching attribute.
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*/
|
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if (!rc) {
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register u32 avl;
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|
|
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avl = le32_to_cpu(
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a->data.resident.value_length);
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if (val_len == avl)
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return 0;
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if (val_len < avl)
|
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return -ENOENT;
|
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} else if (rc < 0)
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return -ENOENT;
|
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}
|
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}
|
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ntfs_error(vol->sb, "Inode is corrupt. Run chkdsk.");
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NVolSetErrors(vol);
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return -EIO;
|
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}
|
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|
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/**
|
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* load_attribute_list - load an attribute list into memory
|
|
* @vol: ntfs volume from which to read
|
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* @runlist: runlist of the attribute list
|
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* @al_start: destination buffer
|
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* @size: size of the destination buffer in bytes
|
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* @initialized_size: initialized size of the attribute list
|
|
*
|
|
* Walk the runlist @runlist and load all clusters from it copying them into
|
|
* the linear buffer @al. The maximum number of bytes copied to @al is @size
|
|
* bytes. Note, @size does not need to be a multiple of the cluster size. If
|
|
* @initialized_size is less than @size, the region in @al between
|
|
* @initialized_size and @size will be zeroed and not read from disk.
|
|
*
|
|
* Return 0 on success or -errno on error.
|
|
*/
|
|
int load_attribute_list(ntfs_volume *vol, runlist *runlist, u8 *al_start,
|
|
const s64 size, const s64 initialized_size)
|
|
{
|
|
LCN lcn;
|
|
u8 *al = al_start;
|
|
u8 *al_end = al + initialized_size;
|
|
runlist_element *rl;
|
|
struct buffer_head *bh;
|
|
struct super_block *sb;
|
|
unsigned long block_size;
|
|
unsigned long block, max_block;
|
|
int err = 0;
|
|
unsigned char block_size_bits;
|
|
|
|
ntfs_debug("Entering.");
|
|
if (!vol || !runlist || !al || size <= 0 || initialized_size < 0 ||
|
|
initialized_size > size)
|
|
return -EINVAL;
|
|
if (!initialized_size) {
|
|
memset(al, 0, size);
|
|
return 0;
|
|
}
|
|
sb = vol->sb;
|
|
block_size = sb->s_blocksize;
|
|
block_size_bits = sb->s_blocksize_bits;
|
|
down_read(&runlist->lock);
|
|
rl = runlist->rl;
|
|
/* Read all clusters specified by the runlist one run at a time. */
|
|
while (rl->length) {
|
|
lcn = ntfs_rl_vcn_to_lcn(rl, rl->vcn);
|
|
ntfs_debug("Reading vcn = 0x%llx, lcn = 0x%llx.",
|
|
(unsigned long long)rl->vcn,
|
|
(unsigned long long)lcn);
|
|
/* The attribute list cannot be sparse. */
|
|
if (lcn < 0) {
|
|
ntfs_error(sb, "ntfs_rl_vcn_to_lcn() failed. Cannot "
|
|
"read attribute list.");
|
|
goto err_out;
|
|
}
|
|
block = lcn << vol->cluster_size_bits >> block_size_bits;
|
|
/* Read the run from device in chunks of block_size bytes. */
|
|
max_block = block + (rl->length << vol->cluster_size_bits >>
|
|
block_size_bits);
|
|
ntfs_debug("max_block = 0x%lx.", max_block);
|
|
do {
|
|
ntfs_debug("Reading block = 0x%lx.", block);
|
|
bh = sb_bread(sb, block);
|
|
if (!bh) {
|
|
ntfs_error(sb, "sb_bread() failed. Cannot "
|
|
"read attribute list.");
|
|
goto err_out;
|
|
}
|
|
if (al + block_size >= al_end)
|
|
goto do_final;
|
|
memcpy(al, bh->b_data, block_size);
|
|
brelse(bh);
|
|
al += block_size;
|
|
} while (++block < max_block);
|
|
rl++;
|
|
}
|
|
if (initialized_size < size) {
|
|
initialize:
|
|
memset(al_start + initialized_size, 0, size - initialized_size);
|
|
}
|
|
done:
|
|
up_read(&runlist->lock);
|
|
return err;
|
|
do_final:
|
|
if (al < al_end) {
|
|
/*
|
|
* Partial block.
|
|
*
|
|
* Note: The attribute list can be smaller than its allocation
|
|
* by multiple clusters. This has been encountered by at least
|
|
* two people running Windows XP, thus we cannot do any
|
|
* truncation sanity checking here. (AIA)
|
|
*/
|
|
memcpy(al, bh->b_data, al_end - al);
|
|
brelse(bh);
|
|
if (initialized_size < size)
|
|
goto initialize;
|
|
goto done;
|
|
}
|
|
brelse(bh);
|
|
/* Real overflow! */
|
|
ntfs_error(sb, "Attribute list buffer overflow. Read attribute list "
|
|
"is truncated.");
|
|
err_out:
|
|
err = -EIO;
|
|
goto done;
|
|
}
|
|
|
|
/**
|
|
* ntfs_external_attr_find - find an attribute in the attribute list of an inode
|
|
* @type: attribute type to find
|
|
* @name: attribute name to find (optional, i.e. NULL means don't care)
|
|
* @name_len: attribute name length (only needed if @name present)
|
|
* @ic: IGNORE_CASE or CASE_SENSITIVE (ignored if @name not present)
|
|
* @lowest_vcn: lowest vcn to find (optional, non-resident attributes only)
|
|
* @val: attribute value to find (optional, resident attributes only)
|
|
* @val_len: attribute value length
|
|
* @ctx: search context with mft record and attribute to search from
|
|
*
|
|
* You should not need to call this function directly. Use ntfs_attr_lookup()
|
|
* instead.
|
|
*
|
|
* Find an attribute by searching the attribute list for the corresponding
|
|
* attribute list entry. Having found the entry, map the mft record if the
|
|
* attribute is in a different mft record/inode, ntfs_attr_find() the attribute
|
|
* in there and return it.
|
|
*
|
|
* On first search @ctx->ntfs_ino must be the base mft record and @ctx must
|
|
* have been obtained from a call to ntfs_attr_get_search_ctx(). On subsequent
|
|
* calls @ctx->ntfs_ino can be any extent inode, too (@ctx->base_ntfs_ino is
|
|
* then the base inode).
|
|
*
|
|
* After finishing with the attribute/mft record you need to call
|
|
* ntfs_attr_put_search_ctx() to cleanup the search context (unmapping any
|
|
* mapped inodes, etc).
|
|
*
|
|
* If the attribute is found, ntfs_external_attr_find() returns 0 and
|
|
* @ctx->attr will point to the found attribute. @ctx->mrec will point to the
|
|
* mft record in which @ctx->attr is located and @ctx->al_entry will point to
|
|
* the attribute list entry for the attribute.
|
|
*
|
|
* If the attribute is not found, ntfs_external_attr_find() returns -ENOENT and
|
|
* @ctx->attr will point to the attribute in the base mft record before which
|
|
* the attribute being searched for would need to be inserted if such an action
|
|
* were to be desired. @ctx->mrec will point to the mft record in which
|
|
* @ctx->attr is located and @ctx->al_entry will point to the attribute list
|
|
* entry of the attribute before which the attribute being searched for would
|
|
* need to be inserted if such an action were to be desired.
|
|
*
|
|
* Thus to insert the not found attribute, one wants to add the attribute to
|
|
* @ctx->mrec (the base mft record) and if there is not enough space, the
|
|
* attribute should be placed in a newly allocated extent mft record. The
|
|
* attribute list entry for the inserted attribute should be inserted in the
|
|
* attribute list attribute at @ctx->al_entry.
|
|
*
|
|
* On actual error, ntfs_external_attr_find() returns -EIO. In this case
|
|
* @ctx->attr is undefined and in particular do not rely on it not changing.
|
|
*/
|
|
static int ntfs_external_attr_find(const ATTR_TYPE type,
|
|
const ntfschar *name, const u32 name_len,
|
|
const IGNORE_CASE_BOOL ic, const VCN lowest_vcn,
|
|
const u8 *val, const u32 val_len, ntfs_attr_search_ctx *ctx)
|
|
{
|
|
ntfs_inode *base_ni, *ni;
|
|
ntfs_volume *vol;
|
|
ATTR_LIST_ENTRY *al_entry, *next_al_entry;
|
|
u8 *al_start, *al_end;
|
|
ATTR_RECORD *a;
|
|
ntfschar *al_name;
|
|
u32 al_name_len;
|
|
int err = 0;
|
|
static const char *es = " Unmount and run chkdsk.";
|
|
|
|
ni = ctx->ntfs_ino;
|
|
base_ni = ctx->base_ntfs_ino;
|
|
ntfs_debug("Entering for inode 0x%lx, type 0x%x.", ni->mft_no, type);
|
|
if (!base_ni) {
|
|
/* First call happens with the base mft record. */
|
|
base_ni = ctx->base_ntfs_ino = ctx->ntfs_ino;
|
|
ctx->base_mrec = ctx->mrec;
|
|
}
|
|
if (ni == base_ni)
|
|
ctx->base_attr = ctx->attr;
|
|
if (type == AT_END)
|
|
goto not_found;
|
|
vol = base_ni->vol;
|
|
al_start = base_ni->attr_list;
|
|
al_end = al_start + base_ni->attr_list_size;
|
|
if (!ctx->al_entry)
|
|
ctx->al_entry = (ATTR_LIST_ENTRY*)al_start;
|
|
/*
|
|
* Iterate over entries in attribute list starting at @ctx->al_entry,
|
|
* or the entry following that, if @ctx->is_first is TRUE.
|
|
*/
|
|
if (ctx->is_first) {
|
|
al_entry = ctx->al_entry;
|
|
ctx->is_first = FALSE;
|
|
} else
|
|
al_entry = (ATTR_LIST_ENTRY*)((u8*)ctx->al_entry +
|
|
le16_to_cpu(ctx->al_entry->length));
|
|
for (;; al_entry = next_al_entry) {
|
|
/* Out of bounds check. */
|
|
if ((u8*)al_entry < base_ni->attr_list ||
|
|
(u8*)al_entry > al_end)
|
|
break; /* Inode is corrupt. */
|
|
ctx->al_entry = al_entry;
|
|
/* Catch the end of the attribute list. */
|
|
if ((u8*)al_entry == al_end)
|
|
goto not_found;
|
|
if (!al_entry->length)
|
|
break;
|
|
if ((u8*)al_entry + 6 > al_end || (u8*)al_entry +
|
|
le16_to_cpu(al_entry->length) > al_end)
|
|
break;
|
|
next_al_entry = (ATTR_LIST_ENTRY*)((u8*)al_entry +
|
|
le16_to_cpu(al_entry->length));
|
|
if (le32_to_cpu(al_entry->type) > le32_to_cpu(type))
|
|
goto not_found;
|
|
if (type != al_entry->type)
|
|
continue;
|
|
/*
|
|
* If @name is present, compare the two names. If @name is
|
|
* missing, assume we want an unnamed attribute.
|
|
*/
|
|
al_name_len = al_entry->name_length;
|
|
al_name = (ntfschar*)((u8*)al_entry + al_entry->name_offset);
|
|
if (!name) {
|
|
if (al_name_len)
|
|
goto not_found;
|
|
} else if (!ntfs_are_names_equal(al_name, al_name_len, name,
|
|
name_len, ic, vol->upcase, vol->upcase_len)) {
|
|
register int rc;
|
|
|
|
rc = ntfs_collate_names(name, name_len, al_name,
|
|
al_name_len, 1, IGNORE_CASE,
|
|
vol->upcase, vol->upcase_len);
|
|
/*
|
|
* If @name collates before al_name, there is no
|
|
* matching attribute.
|
|
*/
|
|
if (rc == -1)
|
|
goto not_found;
|
|
/* If the strings are not equal, continue search. */
|
|
if (rc)
|
|
continue;
|
|
/*
|
|
* FIXME: Reverse engineering showed 0, IGNORE_CASE but
|
|
* that is inconsistent with ntfs_attr_find(). The
|
|
* subsequent rc checks were also different. Perhaps I
|
|
* made a mistake in one of the two. Need to recheck
|
|
* which is correct or at least see what is going on...
|
|
* (AIA)
|
|
*/
|
|
rc = ntfs_collate_names(name, name_len, al_name,
|
|
al_name_len, 1, CASE_SENSITIVE,
|
|
vol->upcase, vol->upcase_len);
|
|
if (rc == -1)
|
|
goto not_found;
|
|
if (rc)
|
|
continue;
|
|
}
|
|
/*
|
|
* The names match or @name not present and attribute is
|
|
* unnamed. Now check @lowest_vcn. Continue search if the
|
|
* next attribute list entry still fits @lowest_vcn. Otherwise
|
|
* we have reached the right one or the search has failed.
|
|
*/
|
|
if (lowest_vcn && (u8*)next_al_entry >= al_start &&
|
|
(u8*)next_al_entry + 6 < al_end &&
|
|
(u8*)next_al_entry + le16_to_cpu(
|
|
next_al_entry->length) <= al_end &&
|
|
sle64_to_cpu(next_al_entry->lowest_vcn) <=
|
|
lowest_vcn &&
|
|
next_al_entry->type == al_entry->type &&
|
|
next_al_entry->name_length == al_name_len &&
|
|
ntfs_are_names_equal((ntfschar*)((u8*)
|
|
next_al_entry +
|
|
next_al_entry->name_offset),
|
|
next_al_entry->name_length,
|
|
al_name, al_name_len, CASE_SENSITIVE,
|
|
vol->upcase, vol->upcase_len))
|
|
continue;
|
|
if (MREF_LE(al_entry->mft_reference) == ni->mft_no) {
|
|
if (MSEQNO_LE(al_entry->mft_reference) != ni->seq_no) {
|
|
ntfs_error(vol->sb, "Found stale mft "
|
|
"reference in attribute list "
|
|
"of base inode 0x%lx.%s",
|
|
base_ni->mft_no, es);
|
|
err = -EIO;
|
|
break;
|
|
}
|
|
} else { /* Mft references do not match. */
|
|
/* If there is a mapped record unmap it first. */
|
|
if (ni != base_ni)
|
|
unmap_extent_mft_record(ni);
|
|
/* Do we want the base record back? */
|
|
if (MREF_LE(al_entry->mft_reference) ==
|
|
base_ni->mft_no) {
|
|
ni = ctx->ntfs_ino = base_ni;
|
|
ctx->mrec = ctx->base_mrec;
|
|
} else {
|
|
/* We want an extent record. */
|
|
ctx->mrec = map_extent_mft_record(base_ni,
|
|
le64_to_cpu(
|
|
al_entry->mft_reference), &ni);
|
|
if (IS_ERR(ctx->mrec)) {
|
|
ntfs_error(vol->sb, "Failed to map "
|
|
"extent mft record "
|
|
"0x%lx of base inode "
|
|
"0x%lx.%s",
|
|
MREF_LE(al_entry->
|
|
mft_reference),
|
|
base_ni->mft_no, es);
|
|
err = PTR_ERR(ctx->mrec);
|
|
if (err == -ENOENT)
|
|
err = -EIO;
|
|
/* Cause @ctx to be sanitized below. */
|
|
ni = NULL;
|
|
break;
|
|
}
|
|
ctx->ntfs_ino = ni;
|
|
}
|
|
ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec +
|
|
le16_to_cpu(ctx->mrec->attrs_offset));
|
|
}
|
|
/*
|
|
* ctx->vfs_ino, ctx->mrec, and ctx->attr now point to the
|
|
* mft record containing the attribute represented by the
|
|
* current al_entry.
|
|
*/
|
|
/*
|
|
* We could call into ntfs_attr_find() to find the right
|
|
* attribute in this mft record but this would be less
|
|
* efficient and not quite accurate as ntfs_attr_find() ignores
|
|
* the attribute instance numbers for example which become
|
|
* important when one plays with attribute lists. Also,
|
|
* because a proper match has been found in the attribute list
|
|
* entry above, the comparison can now be optimized. So it is
|
|
* worth re-implementing a simplified ntfs_attr_find() here.
|
|
*/
|
|
a = ctx->attr;
|
|
/*
|
|
* Use a manual loop so we can still use break and continue
|
|
* with the same meanings as above.
|
|
*/
|
|
do_next_attr_loop:
|
|
if ((u8*)a < (u8*)ctx->mrec || (u8*)a > (u8*)ctx->mrec +
|
|
le32_to_cpu(ctx->mrec->bytes_allocated))
|
|
break;
|
|
if (a->type == AT_END)
|
|
continue;
|
|
if (!a->length)
|
|
break;
|
|
if (al_entry->instance != a->instance)
|
|
goto do_next_attr;
|
|
/*
|
|
* If the type and/or the name are mismatched between the
|
|
* attribute list entry and the attribute record, there is
|
|
* corruption so we break and return error EIO.
|
|
*/
|
|
if (al_entry->type != a->type)
|
|
break;
|
|
if (!ntfs_are_names_equal((ntfschar*)((u8*)a +
|
|
le16_to_cpu(a->name_offset)), a->name_length,
|
|
al_name, al_name_len, CASE_SENSITIVE,
|
|
vol->upcase, vol->upcase_len))
|
|
break;
|
|
ctx->attr = a;
|
|
/*
|
|
* If no @val specified or @val specified and it matches, we
|
|
* have found it!
|
|
*/
|
|
if (!val || (!a->non_resident && le32_to_cpu(
|
|
a->data.resident.value_length) == val_len &&
|
|
!memcmp((u8*)a +
|
|
le16_to_cpu(a->data.resident.value_offset),
|
|
val, val_len))) {
|
|
ntfs_debug("Done, found.");
|
|
return 0;
|
|
}
|
|
do_next_attr:
|
|
/* Proceed to the next attribute in the current mft record. */
|
|
a = (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length));
|
|
goto do_next_attr_loop;
|
|
}
|
|
if (!err) {
|
|
ntfs_error(vol->sb, "Base inode 0x%lx contains corrupt "
|
|
"attribute list attribute.%s", base_ni->mft_no,
|
|
es);
|
|
err = -EIO;
|
|
}
|
|
if (ni != base_ni) {
|
|
if (ni)
|
|
unmap_extent_mft_record(ni);
|
|
ctx->ntfs_ino = base_ni;
|
|
ctx->mrec = ctx->base_mrec;
|
|
ctx->attr = ctx->base_attr;
|
|
}
|
|
if (err != -ENOMEM)
|
|
NVolSetErrors(vol);
|
|
return err;
|
|
not_found:
|
|
/*
|
|
* If we were looking for AT_END, we reset the search context @ctx and
|
|
* use ntfs_attr_find() to seek to the end of the base mft record.
|
|
*/
|
|
if (type == AT_END) {
|
|
ntfs_attr_reinit_search_ctx(ctx);
|
|
return ntfs_attr_find(AT_END, name, name_len, ic, val, val_len,
|
|
ctx);
|
|
}
|
|
/*
|
|
* The attribute was not found. Before we return, we want to ensure
|
|
* @ctx->mrec and @ctx->attr indicate the position at which the
|
|
* attribute should be inserted in the base mft record. Since we also
|
|
* want to preserve @ctx->al_entry we cannot reinitialize the search
|
|
* context using ntfs_attr_reinit_search_ctx() as this would set
|
|
* @ctx->al_entry to NULL. Thus we do the necessary bits manually (see
|
|
* ntfs_attr_init_search_ctx() below). Note, we _only_ preserve
|
|
* @ctx->al_entry as the remaining fields (base_*) are identical to
|
|
* their non base_ counterparts and we cannot set @ctx->base_attr
|
|
* correctly yet as we do not know what @ctx->attr will be set to by
|
|
* the call to ntfs_attr_find() below.
|
|
*/
|
|
if (ni != base_ni)
|
|
unmap_extent_mft_record(ni);
|
|
ctx->mrec = ctx->base_mrec;
|
|
ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec +
|
|
le16_to_cpu(ctx->mrec->attrs_offset));
|
|
ctx->is_first = TRUE;
|
|
ctx->ntfs_ino = base_ni;
|
|
ctx->base_ntfs_ino = NULL;
|
|
ctx->base_mrec = NULL;
|
|
ctx->base_attr = NULL;
|
|
/*
|
|
* In case there are multiple matches in the base mft record, need to
|
|
* keep enumerating until we get an attribute not found response (or
|
|
* another error), otherwise we would keep returning the same attribute
|
|
* over and over again and all programs using us for enumeration would
|
|
* lock up in a tight loop.
|
|
*/
|
|
do {
|
|
err = ntfs_attr_find(type, name, name_len, ic, val, val_len,
|
|
ctx);
|
|
} while (!err);
|
|
ntfs_debug("Done, not found.");
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* ntfs_attr_lookup - find an attribute in an ntfs inode
|
|
* @type: attribute type to find
|
|
* @name: attribute name to find (optional, i.e. NULL means don't care)
|
|
* @name_len: attribute name length (only needed if @name present)
|
|
* @ic: IGNORE_CASE or CASE_SENSITIVE (ignored if @name not present)
|
|
* @lowest_vcn: lowest vcn to find (optional, non-resident attributes only)
|
|
* @val: attribute value to find (optional, resident attributes only)
|
|
* @val_len: attribute value length
|
|
* @ctx: search context with mft record and attribute to search from
|
|
*
|
|
* Find an attribute in an ntfs inode. On first search @ctx->ntfs_ino must
|
|
* be the base mft record and @ctx must have been obtained from a call to
|
|
* ntfs_attr_get_search_ctx().
|
|
*
|
|
* This function transparently handles attribute lists and @ctx is used to
|
|
* continue searches where they were left off at.
|
|
*
|
|
* After finishing with the attribute/mft record you need to call
|
|
* ntfs_attr_put_search_ctx() to cleanup the search context (unmapping any
|
|
* mapped inodes, etc).
|
|
*
|
|
* Return 0 if the search was successful and -errno if not.
|
|
*
|
|
* When 0, @ctx->attr is the found attribute and it is in mft record
|
|
* @ctx->mrec. If an attribute list attribute is present, @ctx->al_entry is
|
|
* the attribute list entry of the found attribute.
|
|
*
|
|
* When -ENOENT, @ctx->attr is the attribute which collates just after the
|
|
* attribute being searched for, i.e. if one wants to add the attribute to the
|
|
* mft record this is the correct place to insert it into. If an attribute
|
|
* list attribute is present, @ctx->al_entry is the attribute list entry which
|
|
* collates just after the attribute list entry of the attribute being searched
|
|
* for, i.e. if one wants to add the attribute to the mft record this is the
|
|
* correct place to insert its attribute list entry into.
|
|
*
|
|
* When -errno != -ENOENT, an error occured during the lookup. @ctx->attr is
|
|
* then undefined and in particular you should not rely on it not changing.
|
|
*/
|
|
int ntfs_attr_lookup(const ATTR_TYPE type, const ntfschar *name,
|
|
const u32 name_len, const IGNORE_CASE_BOOL ic,
|
|
const VCN lowest_vcn, const u8 *val, const u32 val_len,
|
|
ntfs_attr_search_ctx *ctx)
|
|
{
|
|
ntfs_inode *base_ni;
|
|
|
|
ntfs_debug("Entering.");
|
|
if (ctx->base_ntfs_ino)
|
|
base_ni = ctx->base_ntfs_ino;
|
|
else
|
|
base_ni = ctx->ntfs_ino;
|
|
/* Sanity check, just for debugging really. */
|
|
BUG_ON(!base_ni);
|
|
if (!NInoAttrList(base_ni) || type == AT_ATTRIBUTE_LIST)
|
|
return ntfs_attr_find(type, name, name_len, ic, val, val_len,
|
|
ctx);
|
|
return ntfs_external_attr_find(type, name, name_len, ic, lowest_vcn,
|
|
val, val_len, ctx);
|
|
}
|
|
|
|
/**
|
|
* ntfs_attr_init_search_ctx - initialize an attribute search context
|
|
* @ctx: attribute search context to initialize
|
|
* @ni: ntfs inode with which to initialize the search context
|
|
* @mrec: mft record with which to initialize the search context
|
|
*
|
|
* Initialize the attribute search context @ctx with @ni and @mrec.
|
|
*/
|
|
static inline void ntfs_attr_init_search_ctx(ntfs_attr_search_ctx *ctx,
|
|
ntfs_inode *ni, MFT_RECORD *mrec)
|
|
{
|
|
ctx->mrec = mrec;
|
|
/* Sanity checks are performed elsewhere. */
|
|
ctx->attr = (ATTR_RECORD*)((u8*)mrec + le16_to_cpu(mrec->attrs_offset));
|
|
ctx->is_first = TRUE;
|
|
ctx->ntfs_ino = ni;
|
|
ctx->al_entry = NULL;
|
|
ctx->base_ntfs_ino = NULL;
|
|
ctx->base_mrec = NULL;
|
|
ctx->base_attr = NULL;
|
|
}
|
|
|
|
/**
|
|
* ntfs_attr_reinit_search_ctx - reinitialize an attribute search context
|
|
* @ctx: attribute search context to reinitialize
|
|
*
|
|
* Reinitialize the attribute search context @ctx, unmapping an associated
|
|
* extent mft record if present, and initialize the search context again.
|
|
*
|
|
* This is used when a search for a new attribute is being started to reset
|
|
* the search context to the beginning.
|
|
*/
|
|
void ntfs_attr_reinit_search_ctx(ntfs_attr_search_ctx *ctx)
|
|
{
|
|
if (likely(!ctx->base_ntfs_ino)) {
|
|
/* No attribute list. */
|
|
ctx->is_first = TRUE;
|
|
/* Sanity checks are performed elsewhere. */
|
|
ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec +
|
|
le16_to_cpu(ctx->mrec->attrs_offset));
|
|
/*
|
|
* This needs resetting due to ntfs_external_attr_find() which
|
|
* can leave it set despite having zeroed ctx->base_ntfs_ino.
|
|
*/
|
|
ctx->al_entry = NULL;
|
|
return;
|
|
} /* Attribute list. */
|
|
if (ctx->ntfs_ino != ctx->base_ntfs_ino)
|
|
unmap_extent_mft_record(ctx->ntfs_ino);
|
|
ntfs_attr_init_search_ctx(ctx, ctx->base_ntfs_ino, ctx->base_mrec);
|
|
return;
|
|
}
|
|
|
|
/**
|
|
* ntfs_attr_get_search_ctx - allocate/initialize a new attribute search context
|
|
* @ni: ntfs inode with which to initialize the search context
|
|
* @mrec: mft record with which to initialize the search context
|
|
*
|
|
* Allocate a new attribute search context, initialize it with @ni and @mrec,
|
|
* and return it. Return NULL if allocation failed.
|
|
*/
|
|
ntfs_attr_search_ctx *ntfs_attr_get_search_ctx(ntfs_inode *ni, MFT_RECORD *mrec)
|
|
{
|
|
ntfs_attr_search_ctx *ctx;
|
|
|
|
ctx = kmem_cache_alloc(ntfs_attr_ctx_cache, SLAB_NOFS);
|
|
if (ctx)
|
|
ntfs_attr_init_search_ctx(ctx, ni, mrec);
|
|
return ctx;
|
|
}
|
|
|
|
/**
|
|
* ntfs_attr_put_search_ctx - release an attribute search context
|
|
* @ctx: attribute search context to free
|
|
*
|
|
* Release the attribute search context @ctx, unmapping an associated extent
|
|
* mft record if present.
|
|
*/
|
|
void ntfs_attr_put_search_ctx(ntfs_attr_search_ctx *ctx)
|
|
{
|
|
if (ctx->base_ntfs_ino && ctx->ntfs_ino != ctx->base_ntfs_ino)
|
|
unmap_extent_mft_record(ctx->ntfs_ino);
|
|
kmem_cache_free(ntfs_attr_ctx_cache, ctx);
|
|
return;
|
|
}
|
|
|
|
/**
|
|
* ntfs_attr_find_in_attrdef - find an attribute in the $AttrDef system file
|
|
* @vol: ntfs volume to which the attribute belongs
|
|
* @type: attribute type which to find
|
|
*
|
|
* Search for the attribute definition record corresponding to the attribute
|
|
* @type in the $AttrDef system file.
|
|
*
|
|
* Return the attribute type definition record if found and NULL if not found.
|
|
*/
|
|
static ATTR_DEF *ntfs_attr_find_in_attrdef(const ntfs_volume *vol,
|
|
const ATTR_TYPE type)
|
|
{
|
|
ATTR_DEF *ad;
|
|
|
|
BUG_ON(!vol->attrdef);
|
|
BUG_ON(!type);
|
|
for (ad = vol->attrdef; (u8*)ad - (u8*)vol->attrdef <
|
|
vol->attrdef_size && ad->type; ++ad) {
|
|
/* We have not found it yet, carry on searching. */
|
|
if (likely(le32_to_cpu(ad->type) < le32_to_cpu(type)))
|
|
continue;
|
|
/* We found the attribute; return it. */
|
|
if (likely(ad->type == type))
|
|
return ad;
|
|
/* We have gone too far already. No point in continuing. */
|
|
break;
|
|
}
|
|
/* Attribute not found. */
|
|
ntfs_debug("Attribute type 0x%x not found in $AttrDef.",
|
|
le32_to_cpu(type));
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* ntfs_attr_size_bounds_check - check a size of an attribute type for validity
|
|
* @vol: ntfs volume to which the attribute belongs
|
|
* @type: attribute type which to check
|
|
* @size: size which to check
|
|
*
|
|
* Check whether the @size in bytes is valid for an attribute of @type on the
|
|
* ntfs volume @vol. This information is obtained from $AttrDef system file.
|
|
*
|
|
* Return 0 if valid, -ERANGE if not valid, or -ENOENT if the attribute is not
|
|
* listed in $AttrDef.
|
|
*/
|
|
int ntfs_attr_size_bounds_check(const ntfs_volume *vol, const ATTR_TYPE type,
|
|
const s64 size)
|
|
{
|
|
ATTR_DEF *ad;
|
|
|
|
BUG_ON(size < 0);
|
|
/*
|
|
* $ATTRIBUTE_LIST has a maximum size of 256kiB, but this is not
|
|
* listed in $AttrDef.
|
|
*/
|
|
if (unlikely(type == AT_ATTRIBUTE_LIST && size > 256 * 1024))
|
|
return -ERANGE;
|
|
/* Get the $AttrDef entry for the attribute @type. */
|
|
ad = ntfs_attr_find_in_attrdef(vol, type);
|
|
if (unlikely(!ad))
|
|
return -ENOENT;
|
|
/* Do the bounds check. */
|
|
if (((sle64_to_cpu(ad->min_size) > 0) &&
|
|
size < sle64_to_cpu(ad->min_size)) ||
|
|
((sle64_to_cpu(ad->max_size) > 0) && size >
|
|
sle64_to_cpu(ad->max_size)))
|
|
return -ERANGE;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* ntfs_attr_can_be_non_resident - check if an attribute can be non-resident
|
|
* @vol: ntfs volume to which the attribute belongs
|
|
* @type: attribute type which to check
|
|
*
|
|
* Check whether the attribute of @type on the ntfs volume @vol is allowed to
|
|
* be non-resident. This information is obtained from $AttrDef system file.
|
|
*
|
|
* Return 0 if the attribute is allowed to be non-resident, -EPERM if not, or
|
|
* -ENOENT if the attribute is not listed in $AttrDef.
|
|
*/
|
|
int ntfs_attr_can_be_non_resident(const ntfs_volume *vol, const ATTR_TYPE type)
|
|
{
|
|
ATTR_DEF *ad;
|
|
|
|
/*
|
|
* $DATA is always allowed to be non-resident even if $AttrDef does not
|
|
* specify this in the flags of the $DATA attribute definition record.
|
|
*/
|
|
if (type == AT_DATA)
|
|
return 0;
|
|
/* Find the attribute definition record in $AttrDef. */
|
|
ad = ntfs_attr_find_in_attrdef(vol, type);
|
|
if (unlikely(!ad))
|
|
return -ENOENT;
|
|
/* Check the flags and return the result. */
|
|
if (ad->flags & CAN_BE_NON_RESIDENT)
|
|
return 0;
|
|
return -EPERM;
|
|
}
|
|
|
|
/**
|
|
* ntfs_attr_can_be_resident - check if an attribute can be resident
|
|
* @vol: ntfs volume to which the attribute belongs
|
|
* @type: attribute type which to check
|
|
*
|
|
* Check whether the attribute of @type on the ntfs volume @vol is allowed to
|
|
* be resident. This information is derived from our ntfs knowledge and may
|
|
* not be completely accurate, especially when user defined attributes are
|
|
* present. Basically we allow everything to be resident except for index
|
|
* allocation and $EA attributes.
|
|
*
|
|
* Return 0 if the attribute is allowed to be non-resident and -EPERM if not.
|
|
*
|
|
* Warning: In the system file $MFT the attribute $Bitmap must be non-resident
|
|
* otherwise windows will not boot (blue screen of death)! We cannot
|
|
* check for this here as we do not know which inode's $Bitmap is
|
|
* being asked about so the caller needs to special case this.
|
|
*/
|
|
int ntfs_attr_can_be_resident(const ntfs_volume *vol, const ATTR_TYPE type)
|
|
{
|
|
if (type != AT_INDEX_ALLOCATION && type != AT_EA)
|
|
return 0;
|
|
return -EPERM;
|
|
}
|
|
|
|
/**
|
|
* ntfs_attr_record_resize - resize an attribute record
|
|
* @m: mft record containing attribute record
|
|
* @a: attribute record to resize
|
|
* @new_size: new size in bytes to which to resize the attribute record @a
|
|
*
|
|
* Resize the attribute record @a, i.e. the resident part of the attribute, in
|
|
* the mft record @m to @new_size bytes.
|
|
*
|
|
* Return 0 on success and -errno on error. The following error codes are
|
|
* defined:
|
|
* -ENOSPC - Not enough space in the mft record @m to perform the resize.
|
|
*
|
|
* Note: On error, no modifications have been performed whatsoever.
|
|
*
|
|
* Warning: If you make a record smaller without having copied all the data you
|
|
* are interested in the data may be overwritten.
|
|
*/
|
|
int ntfs_attr_record_resize(MFT_RECORD *m, ATTR_RECORD *a, u32 new_size)
|
|
{
|
|
ntfs_debug("Entering for new_size %u.", new_size);
|
|
/* Align to 8 bytes if it is not already done. */
|
|
if (new_size & 7)
|
|
new_size = (new_size + 7) & ~7;
|
|
/* If the actual attribute length has changed, move things around. */
|
|
if (new_size != le32_to_cpu(a->length)) {
|
|
u32 new_muse = le32_to_cpu(m->bytes_in_use) -
|
|
le32_to_cpu(a->length) + new_size;
|
|
/* Not enough space in this mft record. */
|
|
if (new_muse > le32_to_cpu(m->bytes_allocated))
|
|
return -ENOSPC;
|
|
/* Move attributes following @a to their new location. */
|
|
memmove((u8*)a + new_size, (u8*)a + le32_to_cpu(a->length),
|
|
le32_to_cpu(m->bytes_in_use) - ((u8*)a -
|
|
(u8*)m) - le32_to_cpu(a->length));
|
|
/* Adjust @m to reflect the change in used space. */
|
|
m->bytes_in_use = cpu_to_le32(new_muse);
|
|
/* Adjust @a to reflect the new size. */
|
|
if (new_size >= offsetof(ATTR_REC, length) + sizeof(a->length))
|
|
a->length = cpu_to_le32(new_size);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* ntfs_attr_set - fill (a part of) an attribute with a byte
|
|
* @ni: ntfs inode describing the attribute to fill
|
|
* @ofs: offset inside the attribute at which to start to fill
|
|
* @cnt: number of bytes to fill
|
|
* @val: the unsigned 8-bit value with which to fill the attribute
|
|
*
|
|
* Fill @cnt bytes of the attribute described by the ntfs inode @ni starting at
|
|
* byte offset @ofs inside the attribute with the constant byte @val.
|
|
*
|
|
* This function is effectively like memset() applied to an ntfs attribute.
|
|
* Note thie function actually only operates on the page cache pages belonging
|
|
* to the ntfs attribute and it marks them dirty after doing the memset().
|
|
* Thus it relies on the vm dirty page write code paths to cause the modified
|
|
* pages to be written to the mft record/disk.
|
|
*
|
|
* Return 0 on success and -errno on error. An error code of -ESPIPE means
|
|
* that @ofs + @cnt were outside the end of the attribute and no write was
|
|
* performed.
|
|
*/
|
|
int ntfs_attr_set(ntfs_inode *ni, const s64 ofs, const s64 cnt, const u8 val)
|
|
{
|
|
ntfs_volume *vol = ni->vol;
|
|
struct address_space *mapping;
|
|
struct page *page;
|
|
u8 *kaddr;
|
|
pgoff_t idx, end;
|
|
unsigned int start_ofs, end_ofs, size;
|
|
|
|
ntfs_debug("Entering for ofs 0x%llx, cnt 0x%llx, val 0x%hx.",
|
|
(long long)ofs, (long long)cnt, val);
|
|
BUG_ON(ofs < 0);
|
|
BUG_ON(cnt < 0);
|
|
if (!cnt)
|
|
goto done;
|
|
mapping = VFS_I(ni)->i_mapping;
|
|
/* Work out the starting index and page offset. */
|
|
idx = ofs >> PAGE_CACHE_SHIFT;
|
|
start_ofs = ofs & ~PAGE_CACHE_MASK;
|
|
/* Work out the ending index and page offset. */
|
|
end = ofs + cnt;
|
|
end_ofs = end & ~PAGE_CACHE_MASK;
|
|
/* If the end is outside the inode size return -ESPIPE. */
|
|
if (unlikely(end > i_size_read(VFS_I(ni)))) {
|
|
ntfs_error(vol->sb, "Request exceeds end of attribute.");
|
|
return -ESPIPE;
|
|
}
|
|
end >>= PAGE_CACHE_SHIFT;
|
|
/* If there is a first partial page, need to do it the slow way. */
|
|
if (start_ofs) {
|
|
page = read_cache_page(mapping, idx,
|
|
(filler_t*)mapping->a_ops->readpage, NULL);
|
|
if (IS_ERR(page)) {
|
|
ntfs_error(vol->sb, "Failed to read first partial "
|
|
"page (sync error, index 0x%lx).", idx);
|
|
return PTR_ERR(page);
|
|
}
|
|
wait_on_page_locked(page);
|
|
if (unlikely(!PageUptodate(page))) {
|
|
ntfs_error(vol->sb, "Failed to read first partial page "
|
|
"(async error, index 0x%lx).", idx);
|
|
page_cache_release(page);
|
|
return PTR_ERR(page);
|
|
}
|
|
/*
|
|
* If the last page is the same as the first page, need to
|
|
* limit the write to the end offset.
|
|
*/
|
|
size = PAGE_CACHE_SIZE;
|
|
if (idx == end)
|
|
size = end_ofs;
|
|
kaddr = kmap_atomic(page, KM_USER0);
|
|
memset(kaddr + start_ofs, val, size - start_ofs);
|
|
flush_dcache_page(page);
|
|
kunmap_atomic(kaddr, KM_USER0);
|
|
set_page_dirty(page);
|
|
page_cache_release(page);
|
|
if (idx == end)
|
|
goto done;
|
|
idx++;
|
|
}
|
|
/* Do the whole pages the fast way. */
|
|
for (; idx < end; idx++) {
|
|
/* Find or create the current page. (The page is locked.) */
|
|
page = grab_cache_page(mapping, idx);
|
|
if (unlikely(!page)) {
|
|
ntfs_error(vol->sb, "Insufficient memory to grab "
|
|
"page (index 0x%lx).", idx);
|
|
return -ENOMEM;
|
|
}
|
|
kaddr = kmap_atomic(page, KM_USER0);
|
|
memset(kaddr, val, PAGE_CACHE_SIZE);
|
|
flush_dcache_page(page);
|
|
kunmap_atomic(kaddr, KM_USER0);
|
|
/*
|
|
* If the page has buffers, mark them uptodate since buffer
|
|
* state and not page state is definitive in 2.6 kernels.
|
|
*/
|
|
if (page_has_buffers(page)) {
|
|
struct buffer_head *bh, *head;
|
|
|
|
bh = head = page_buffers(page);
|
|
do {
|
|
set_buffer_uptodate(bh);
|
|
} while ((bh = bh->b_this_page) != head);
|
|
}
|
|
/* Now that buffers are uptodate, set the page uptodate, too. */
|
|
SetPageUptodate(page);
|
|
/*
|
|
* Set the page and all its buffers dirty and mark the inode
|
|
* dirty, too. The VM will write the page later on.
|
|
*/
|
|
set_page_dirty(page);
|
|
/* Finally unlock and release the page. */
|
|
unlock_page(page);
|
|
page_cache_release(page);
|
|
}
|
|
/* If there is a last partial page, need to do it the slow way. */
|
|
if (end_ofs) {
|
|
page = read_cache_page(mapping, idx,
|
|
(filler_t*)mapping->a_ops->readpage, NULL);
|
|
if (IS_ERR(page)) {
|
|
ntfs_error(vol->sb, "Failed to read last partial page "
|
|
"(sync error, index 0x%lx).", idx);
|
|
return PTR_ERR(page);
|
|
}
|
|
wait_on_page_locked(page);
|
|
if (unlikely(!PageUptodate(page))) {
|
|
ntfs_error(vol->sb, "Failed to read last partial page "
|
|
"(async error, index 0x%lx).", idx);
|
|
page_cache_release(page);
|
|
return PTR_ERR(page);
|
|
}
|
|
kaddr = kmap_atomic(page, KM_USER0);
|
|
memset(kaddr, val, end_ofs);
|
|
flush_dcache_page(page);
|
|
kunmap_atomic(kaddr, KM_USER0);
|
|
set_page_dirty(page);
|
|
page_cache_release(page);
|
|
}
|
|
done:
|
|
ntfs_debug("Done.");
|
|
return 0;
|
|
}
|