fs/ntfs/attrlist.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Attribute list attribute handling code.
 * Part of this file is based on code from the NTFS-3G.
 *
 * Copyright (c) 2004-2005 Anton Altaparmakov
 * Copyright (c) 2004-2005 Yura Pakhuchiy
 * Copyright (c)      2006 Szabolcs Szakacsits
 * Copyright (c) 2025 LG Electronics Co., Ltd.
 */

#include "mft.h"
#include "attrib.h"
#include "attrlist.h"
#include "lcnalloc.h"

#define NTFS_MAX_ATTR_LIST_SIZE	(256 * 1024)

/*
 * ntfs_attrlist_need - check whether inode need attribute list
 * @ni:	opened ntfs inode for which perform check
 *
 * Check whether all are attributes belong to one MFT record, in that case
 * attribute list is not needed.
 *
 * Return 1 if inode need attribute list, 0 if not, or -errno on error.
 */
int ntfs_attrlist_need(struct ntfs_inode *ni)
{
	struct attr_list_entry *ale;

	if (!ni) {
		ntfs_debug("Invalid arguments.\n");
		return -EINVAL;
	}
	ntfs_debug("Entering for inode 0x%llx.\n", (long long) ni->mft_no);

	if (!NInoAttrList(ni)) {
		ntfs_debug("Inode haven't got attribute list.\n");
		return -EINVAL;
	}

	if (!ni->attr_list) {
		ntfs_debug("Corrupt in-memory struct.\n");
		return -EINVAL;
	}

	ale = (struct attr_list_entry *)ni->attr_list;
	while ((u8 *)ale < ni->attr_list + ni->attr_list_size) {
		if (MREF_LE(ale->mft_reference) != ni->mft_no)
			return 1;
		ale = (struct attr_list_entry *)((u8 *)ale + le16_to_cpu(ale->length));
	}
	return 0;
}

/*
 * Repack the $MFT/$ATTRIBUTE_LIST data into one run.
 *
 * The mapping pairs for an $ATTRIBUTE_LIST must remain in the base MFT
 * record. Once that record has no room left, extending a fragmented list
 * can require one more mapping-pairs byte than the record can hold. There
 * is no attribute that can legally be moved out in that state: $STANDARD_
 * INFORMATION, $ATTRIBUTE_LIST, and the first $MFT/$DATA extent all have to
 * stay in the base record.  Move the list data to one contiguous run. The
 * caller supplies the minimum allocation size so a recovery can use the
 * smallest useful run while normal updates can still request the maximum
 * legal list size as a reserve.
 */
static int ntfs_attrlist_repack(struct inode *attr_vi,
		struct ntfs_inode *attr_ni, s64 min_alloc_size,
		struct ntfs_inode *locked_ni)
{
	struct ntfs_volume *vol = attr_ni->vol;
	struct runlist_element *old_rl, *new_rl;
	u8 *data = NULL;
	s64 data_size, alloc_size, nr_clusters, written;
	s64 old_alloc_size;
	size_t old_rl_count, new_rl_count;
	unsigned long flags;
	int err, restore_err;
	if (attr_ni->mft_no != FILE_MFT || !NInoNonResident(attr_ni) ||
		min_alloc_size < 0)
		return -EINVAL;
	/* The buffered I/O below can reacquire the attribute runlist lock. */
	if (attr_ni == locked_ni)
		return -ENOSPC;

	err = ntfs_attr_map_whole_runlist(attr_ni);
	if (err)
		return err;

	data_size = attr_ni->data_size;
	if (data_size < 0)
		return -EIO;

	if (data_size) {
		data = kvmalloc(data_size, GFP_NOFS);
		if (!data)
			return -ENOMEM;

		written = ntfs_inode_attr_pread(attr_vi, 0, data_size, data);
		if (written != data_size) {
			err = written < 0 ? (int)written : -EIO;
			goto out_free_data;
		}
	}

	old_alloc_size = attr_ni->allocated_size;
	alloc_size = max_t(s64, old_alloc_size, min_alloc_size);
	nr_clusters = ntfs_bytes_to_cluster(vol,
			alloc_size + vol->cluster_size - 1);
	if (nr_clusters <= 0) {
		err = -EFBIG;
		goto out_free_data;
	}

	/* A single run keeps the mapping pairs at the minimum size. */
	new_rl = ntfs_cluster_alloc(vol, 0, nr_clusters, -1, DATA_ZONE,
				    true, true, false);
	if (IS_ERR(new_rl)) {
		err = PTR_ERR(new_rl);
		goto out_free_data;
	}

	new_rl_count = 0;
	if (new_rl->vcn == 0 && new_rl->length == nr_clusters &&
		!new_rl[1].length)
		new_rl_count = 2;

	if (new_rl_count != 2) {
		ntfs_cluster_free_from_rl(vol, new_rl);
		kvfree(new_rl);
		err = -ENOSPC;
		goto out_free_data;
	}
	old_rl = attr_ni->runlist.rl;
	old_rl_count = attr_ni->runlist.count;
	down_write(&attr_ni->runlist.lock);
	attr_ni->runlist.rl = new_rl;
	attr_ni->runlist.count = new_rl_count;
	up_write(&attr_ni->runlist.lock);

	write_lock_irqsave(&attr_ni->size_lock, flags);
	attr_ni->allocated_size = ntfs_cluster_to_bytes(vol, nr_clusters);
	write_unlock_irqrestore(&attr_ni->size_lock, flags);

	/* Populate the replacement extent before publishing its mapping pairs. */
	if (data_size) {
		written = ntfs_inode_attr_pwrite(attr_vi, 0, data_size, data, true);
		if (written != data_size) {
			err = written < 0 ? (int)written : -EIO;
			goto restore_old_runlist;
		}
	}

	err = ntfs_attr_update_mapping_pairs_locked(attr_ni, 0, locked_ni);
	if (err)
		goto restore_old_runlist;

	/* The new mapping is now authoritative; release the old data runs. */
	if (ntfs_cluster_free_from_rl(vol, old_rl)) {
		ntfs_error(vol->sb,
			   "Failed to free old ATTRIBUTE_LIST extent: inode %#llx",
			   (long long)attr_ni->mft_no);
		NVolSetErrors(vol);
	}
	kvfree(old_rl);
	kvfree(data);
	return 0;

restore_old_runlist:
	down_write(&attr_ni->runlist.lock);
	attr_ni->runlist.rl = old_rl;
	attr_ni->runlist.count = old_rl_count;
	up_write(&attr_ni->runlist.lock);

	write_lock_irqsave(&attr_ni->size_lock, flags);
	attr_ni->allocated_size = old_alloc_size;
	write_unlock_irqrestore(&attr_ni->size_lock, flags);

	restore_err = ntfs_attr_update_mapping_pairs_locked(
			attr_ni, 0, locked_ni);
	if (restore_err) {
		ntfs_error(vol->sb, "Failed to restore ATTRIBUTE_LIST mapping pairs (%d)",
			   restore_err);
		NVolSetErrors(vol);
	}

	ntfs_cluster_free_from_rl(vol, new_rl);
	kvfree(new_rl);
	err = err ? err : restore_err;

out_free_data:
	kvfree(data);
	return err;
}

int ntfs_attrlist_update_locked(struct ntfs_inode *base_ni,
				struct ntfs_inode *locked_ni)
{
	struct inode *attr_vi;
	struct ntfs_inode *attr_ni;
	s64 written;
	int err, retry_err;

	/*
	 * generic_shutdown_super() clears SB_ACTIVE before evicting cached
	 * inodes. Do not look up the attribute-list inode after SB_ACTIVE has
	 * been cleared; it may already be I_FREEING, and waiting on it can
	 * self-deadlock.
	 */
	if (!(VFS_I(base_ni)->i_sb->s_flags & SB_ACTIVE))
		return -EIO;

	attr_vi = ntfs_attr_iget(VFS_I(base_ni), AT_ATTRIBUTE_LIST, AT_UNNAMED, 0);
	if (IS_ERR(attr_vi)) {
		err = PTR_ERR(attr_vi);
		return err;
	}
	attr_ni = NTFS_I(attr_vi);
	/* Truncation and page-cache writes can reacquire this runlist lock. */
	if (attr_ni == locked_ni) {
		iput(attr_vi);
		return -ENOSPC;
	}

	err = ntfs_attr_truncate_i_locked(
			attr_ni, base_ni->attr_list_size, HOLES_NO, locked_ni);
	if (err == -ENOSPC && attr_ni->mft_no == FILE_MFT &&
		NInoNonResident(attr_ni)) {
		retry_err = ntfs_attrlist_repack(attr_vi, attr_ni,
					base_ni->attr_list_size, locked_ni);
		if (retry_err) {
			ntfs_error(base_ni->vol->sb, "Failed to repack attribute list");
			iput(attr_vi);
			return retry_err;
		}

		retry_err = ntfs_attr_truncate_i_locked(
				attr_ni, base_ni->attr_list_size,
				HOLES_NO, locked_ni);
		if (retry_err) {
			ntfs_error(base_ni->vol->sb,
				   "Failed to resize attribute list after repack");
			iput(attr_vi);
			return retry_err;
		}
	} else if (err) {
		iput(attr_vi);
		ntfs_error(base_ni->vol->sb,
			   "Failed to truncate attribute list of inode %#llx",
			   (long long)base_ni->mft_no);
		return err;
	}

	/*
	 * Reserve the maximum legal list size while the MFT metadata area is
	 * still easy to allocate contiguously. This prevents a later list entry
	 * from needing another mapping-pairs byte in the full base MFT record.
	 * Failure to obtain the optional reserve must not reject the current
	 * metadata update; the repack retry above remains available if needed.
	 */
	if (base_ni->mft_no == FILE_MFT && NInoNonResident(attr_ni) &&
		attr_ni->allocated_size < NTFS_MAX_ATTR_LIST_SIZE) {
		retry_err = ntfs_attr_expand_locked(
				attr_ni, base_ni->attr_list_size,
				NTFS_MAX_ATTR_LIST_SIZE, locked_ni);
		if (retry_err == -ENOSPC) {
			retry_err = ntfs_attrlist_repack(
					attr_vi, attr_ni,
					NTFS_MAX_ATTR_LIST_SIZE, locked_ni);
			if (retry_err == -ENOSPC)
				retry_err = 0;
		}
		if (retry_err) {
			ntfs_error(base_ni->vol->sb,
				   "Failed to reserve attribute list space");
			iput(attr_vi);
			return retry_err;
		}
	}

	i_size_write(attr_vi, base_ni->attr_list_size);

	if (NInoNonResident(attr_ni) && !NInoAttrListNonResident(base_ni))
		NInoSetAttrListNonResident(base_ni);

	written = ntfs_inode_attr_pwrite(attr_vi, 0, base_ni->attr_list_size,
					 base_ni->attr_list, false);
	if (written != base_ni->attr_list_size) {
		err = written < 0 ? (int)written : -EIO;
		iput(attr_vi);
		ntfs_error(base_ni->vol->sb,
			   "Failed to write attribute list of inode %#llx",
			   (long long)base_ni->mft_no);
		return err;
	}

	NInoSetAttrListDirty(base_ni);
	iput(attr_vi);
	return 0;
}

int ntfs_attrlist_update(struct ntfs_inode *base_ni)
{
	return ntfs_attrlist_update_locked(base_ni, NULL);
}

/*
 * ntfs_attrlist_entry_add - add an attribute list attribute entry
 * @ni:	opened ntfs inode, which contains that attribute
 * @attr: attribute record to add to attribute list
 *
 * Return 0 on success and -errno on error.
 */
int ntfs_attrlist_entry_add(struct ntfs_inode *ni, struct attr_record *attr)
{
	struct attr_list_entry *ale;
	__le64 mref;
	struct ntfs_attr_search_ctx *ctx;
	u8 *new_al;
	int entry_len, entry_offset, err;
	struct mft_record *ni_mrec;
	u8 *old_al;
	__le64 lowest_vcn;

	if (!ni || !attr) {
		ntfs_debug("Invalid arguments.\n");
		return -EINVAL;
	}

	ntfs_debug("Entering for inode 0x%llx, attr 0x%x.\n",
			ni->mft_no, (unsigned int) le32_to_cpu(attr->type));

	ni_mrec = map_mft_record(ni);
	if (IS_ERR(ni_mrec)) {
		ntfs_debug("Invalid arguments.\n");
		return -EIO;
	}

	mref = MK_LE_MREF(ni->mft_no, le16_to_cpu(ni_mrec->sequence_number));
	unmap_mft_record(ni);

	if (ni->nr_extents == -1)
		ni = ni->ext.base_ntfs_ino;

	if (!NInoAttrList(ni)) {
		ntfs_debug("Attribute list isn't present.\n");
		return -ENOENT;
	}

	/* Determine size and allocate memory for new attribute list. */
	entry_len = (sizeof(struct attr_list_entry) + sizeof(__le16) *
			attr->name_length + 7) & ~7;
	new_al = kvzalloc(ni->attr_list_size + entry_len, GFP_NOFS);
	if (!new_al)
		return -ENOMEM;

	/* Find place for the new entry. */
	ctx = ntfs_attr_get_search_ctx(ni, NULL);
	if (!ctx) {
		err = -ENOMEM;
		ntfs_error(ni->vol->sb, "Failed to get search context");
		goto err_out;
	}
	if (attr->non_resident)
		lowest_vcn = attr->data.non_resident.lowest_vcn;
	else
		lowest_vcn = 0;

	err = ntfs_attr_lookup(attr->type, (attr->name_length) ? (__le16 *)
			((u8 *)attr + le16_to_cpu(attr->name_offset)) :
			AT_UNNAMED, attr->name_length, CASE_SENSITIVE,
			le64_to_cpu(lowest_vcn),
			(attr->non_resident) ? NULL : ((u8 *)attr +
			le16_to_cpu(attr->data.resident.value_offset)), (attr->non_resident) ?
			0 : le32_to_cpu(attr->data.resident.value_length), ctx);
	if (!err) {
		/* Found some extent, check it to be before new extent. */
		if (ctx->al_entry->lowest_vcn == lowest_vcn) {
			err = -EEXIST;
			ntfs_debug("Such attribute already present in the attribute list.\n");
			ntfs_attr_put_search_ctx(ctx);
			goto err_out;
		}
		/* Add new entry after this extent. */
		ale = (struct attr_list_entry *)((u8 *)ctx->al_entry +
				le16_to_cpu(ctx->al_entry->length));
	} else {
		/* Check for real errors. */
		if (err != -ENOENT) {
			ntfs_debug("Attribute lookup failed.\n");
			ntfs_attr_put_search_ctx(ctx);
			goto err_out;
		}
		/* No previous extents found. */
		ale = ctx->al_entry;
	}
	/* Don't need it anymore, @ctx->al_entry points to @ni->attr_list. */
	ntfs_attr_put_search_ctx(ctx);

	/* Determine new entry offset. */
	entry_offset = ((u8 *)ale - ni->attr_list);
	/* Set pointer to new entry. */
	ale = (struct attr_list_entry *)(new_al + entry_offset);
	memset(ale, 0, entry_len);
	/* Form new entry. */
	ale->type = attr->type;
	ale->length = cpu_to_le16(entry_len);
	ale->name_length = attr->name_length;
	ale->name_offset = offsetof(struct attr_list_entry, name);
	if (attr->non_resident)
		ale->lowest_vcn = attr->data.non_resident.lowest_vcn;
	else
		ale->lowest_vcn = 0;
	ale->mft_reference = mref;
	ale->instance = attr->instance;
	memcpy(ale->name, (u8 *)attr + le16_to_cpu(attr->name_offset),
			attr->name_length * sizeof(__le16));

	/* Copy entries from old attribute list to new. */
	memcpy(new_al, ni->attr_list, entry_offset);
	memcpy(new_al + entry_offset + entry_len, ni->attr_list +
			entry_offset, ni->attr_list_size - entry_offset);

	/* Set new runlist. */
	old_al = ni->attr_list;
	ni->attr_list = new_al;
	ni->attr_list_size = ni->attr_list_size + entry_len;

	err = ntfs_attrlist_update(ni);
	if (err) {
		ni->attr_list = old_al;
		ni->attr_list_size -= entry_len;
		goto err_out;
	}
	kvfree(old_al);
	return 0;
err_out:
	kvfree(new_al);
	return err;
}

/*
 * ntfs_attrlist_entry_rm - remove an attribute list attribute entry
 * @ctx:	attribute search context describing the attribute list entry
 *
 * Remove the attribute list entry @ctx->al_entry from the attribute list.
 *
 * Return 0 on success and -errno on error.
 */
int ntfs_attrlist_entry_rm(struct ntfs_attr_search_ctx *ctx)
{
	u8 *new_al;
	int new_al_len;
	struct ntfs_inode *base_ni;
	struct attr_list_entry *ale;

	if (!ctx || !ctx->ntfs_ino || !ctx->al_entry) {
		ntfs_debug("Invalid arguments.\n");
		return -EINVAL;
	}

	if (ctx->base_ntfs_ino)
		base_ni = ctx->base_ntfs_ino;
	else
		base_ni = ctx->ntfs_ino;
	ale = ctx->al_entry;

	ntfs_debug("Entering for inode 0x%llx, attr 0x%x, lowest_vcn %lld.\n",
			(long long)ctx->ntfs_ino->mft_no,
			(unsigned int)le32_to_cpu(ctx->al_entry->type),
			(long long)le64_to_cpu(ctx->al_entry->lowest_vcn));

	if (!NInoAttrList(base_ni)) {
		ntfs_debug("Attribute list isn't present.\n");
		return -ENOENT;
	}

	/* Allocate memory for new attribute list. */
	new_al_len = base_ni->attr_list_size - le16_to_cpu(ale->length);
	new_al = kvzalloc(new_al_len, GFP_NOFS);
	if (!new_al)
		return -ENOMEM;

	/* Copy entries from old attribute list to new. */
	memcpy(new_al, base_ni->attr_list, (u8 *)ale - base_ni->attr_list);
	memcpy(new_al + ((u8 *)ale - base_ni->attr_list), (u8 *)ale + le16_to_cpu(
				ale->length), new_al_len - ((u8 *)ale - base_ni->attr_list));

	/* Set new runlist. */
	kvfree(base_ni->attr_list);
	base_ni->attr_list = new_al;
	base_ni->attr_list_size = new_al_len;

	return ntfs_attrlist_update(base_ni);
}