ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/fs/incfs/format.c b/marvell/linux/fs/incfs/format.c
new file mode 100644
index 0000000..9128cd2
--- /dev/null
+++ b/marvell/linux/fs/incfs/format.c
@@ -0,0 +1,752 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2018 Google LLC
+ */
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/types.h>
+#include <linux/mutex.h>
+#include <linux/mm.h>
+#include <linux/falloc.h>
+#include <linux/slab.h>
+#include <linux/crc32.h>
+#include <linux/kernel.h>
+
+#include "format.h"
+#include "data_mgmt.h"
+
+struct backing_file_context *incfs_alloc_bfc(struct mount_info *mi,
+ struct file *backing_file)
+{
+ struct backing_file_context *result = NULL;
+
+ result = kzalloc(sizeof(*result), GFP_NOFS);
+ if (!result)
+ return ERR_PTR(-ENOMEM);
+
+ result->bc_file = get_file(backing_file);
+ result->bc_cred = mi->mi_owner;
+ mutex_init(&result->bc_mutex);
+ return result;
+}
+
+void incfs_free_bfc(struct backing_file_context *bfc)
+{
+ if (!bfc)
+ return;
+
+ if (bfc->bc_file)
+ fput(bfc->bc_file);
+
+ mutex_destroy(&bfc->bc_mutex);
+ kfree(bfc);
+}
+
+static loff_t incfs_get_end_offset(struct file *f)
+{
+ /*
+ * This function assumes that file size and the end-offset
+ * are the same. This is not always true.
+ */
+ return i_size_read(file_inode(f));
+}
+
+/*
+ * Truncate the tail of the file to the given length.
+ * Used to rollback partially successful multistep writes.
+ */
+static int truncate_backing_file(struct backing_file_context *bfc,
+ loff_t new_end)
+{
+ struct inode *inode = NULL;
+ struct dentry *dentry = NULL;
+ loff_t old_end = 0;
+ struct iattr attr;
+ int result = 0;
+
+ if (!bfc)
+ return -EFAULT;
+
+ LOCK_REQUIRED(bfc->bc_mutex);
+
+ if (!bfc->bc_file)
+ return -EFAULT;
+
+ old_end = incfs_get_end_offset(bfc->bc_file);
+ if (old_end == new_end)
+ return 0;
+ if (old_end < new_end)
+ return -EINVAL;
+
+ inode = bfc->bc_file->f_inode;
+ dentry = bfc->bc_file->f_path.dentry;
+
+ attr.ia_size = new_end;
+ attr.ia_valid = ATTR_SIZE;
+
+ inode_lock(inode);
+ result = notify_change(dentry, &attr, NULL);
+ inode_unlock(inode);
+
+ return result;
+}
+
+static int write_to_bf(struct backing_file_context *bfc, const void *buf,
+ size_t count, loff_t pos)
+{
+ ssize_t res = incfs_kwrite(bfc, buf, count, pos);
+
+ if (res < 0)
+ return res;
+ if (res != count)
+ return -EIO;
+ return 0;
+}
+
+static int append_zeros_no_fallocate(struct backing_file_context *bfc,
+ size_t file_size, size_t len)
+{
+ u8 buffer[256] = {};
+ size_t i;
+
+ for (i = 0; i < len; i += sizeof(buffer)) {
+ int to_write = len - i > sizeof(buffer)
+ ? sizeof(buffer) : len - i;
+ int err = write_to_bf(bfc, buffer, to_write, file_size + i);
+
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
+/* Append a given number of zero bytes to the end of the backing file. */
+static int append_zeros(struct backing_file_context *bfc, size_t len)
+{
+ loff_t file_size = 0;
+ loff_t new_last_byte_offset = 0;
+ int result;
+
+ if (!bfc)
+ return -EFAULT;
+
+ if (len == 0)
+ return 0;
+
+ LOCK_REQUIRED(bfc->bc_mutex);
+
+ /*
+ * Allocate only one byte at the new desired end of the file.
+ * It will increase file size and create a zeroed area of
+ * a given size.
+ */
+ file_size = incfs_get_end_offset(bfc->bc_file);
+ new_last_byte_offset = file_size + len - 1;
+ result = vfs_fallocate(bfc->bc_file, 0, new_last_byte_offset, 1);
+ if (result != -EOPNOTSUPP)
+ return result;
+
+ return append_zeros_no_fallocate(bfc, file_size, len);
+}
+
+/*
+ * Append a given metadata record to the backing file and update a previous
+ * record to add the new record the the metadata list.
+ */
+static int append_md_to_backing_file(struct backing_file_context *bfc,
+ struct incfs_md_header *record)
+{
+ int result = 0;
+ loff_t record_offset;
+ loff_t file_pos;
+ __le64 new_md_offset;
+ size_t record_size;
+
+ if (!bfc || !record)
+ return -EFAULT;
+
+ if (bfc->bc_last_md_record_offset < 0)
+ return -EINVAL;
+
+ LOCK_REQUIRED(bfc->bc_mutex);
+
+ record_size = le16_to_cpu(record->h_record_size);
+ file_pos = incfs_get_end_offset(bfc->bc_file);
+ record->h_next_md_offset = 0;
+
+ /* Write the metadata record to the end of the backing file */
+ record_offset = file_pos;
+ new_md_offset = cpu_to_le64(record_offset);
+ result = write_to_bf(bfc, record, record_size, file_pos);
+ if (result)
+ return result;
+
+ /* Update next metadata offset in a previous record or a superblock. */
+ if (bfc->bc_last_md_record_offset) {
+ /*
+ * Find a place in the previous md record where new record's
+ * offset needs to be saved.
+ */
+ file_pos = bfc->bc_last_md_record_offset +
+ offsetof(struct incfs_md_header, h_next_md_offset);
+ } else {
+ /*
+ * No metadata yet, file a place to update in the
+ * file_header.
+ */
+ file_pos = offsetof(struct incfs_file_header,
+ fh_first_md_offset);
+ }
+ result = write_to_bf(bfc, &new_md_offset, sizeof(new_md_offset),
+ file_pos);
+ if (result)
+ return result;
+
+ bfc->bc_last_md_record_offset = record_offset;
+ return result;
+}
+
+/*
+ * Reserve 0-filled space for the blockmap body, and append
+ * incfs_blockmap metadata record pointing to it.
+ */
+int incfs_write_blockmap_to_backing_file(struct backing_file_context *bfc,
+ u32 block_count)
+{
+ struct incfs_blockmap blockmap = {};
+ int result = 0;
+ loff_t file_end = 0;
+ size_t map_size = block_count * sizeof(struct incfs_blockmap_entry);
+
+ if (!bfc)
+ return -EFAULT;
+
+ blockmap.m_header.h_md_entry_type = INCFS_MD_BLOCK_MAP;
+ blockmap.m_header.h_record_size = cpu_to_le16(sizeof(blockmap));
+ blockmap.m_header.h_next_md_offset = cpu_to_le64(0);
+ blockmap.m_block_count = cpu_to_le32(block_count);
+
+ LOCK_REQUIRED(bfc->bc_mutex);
+
+ /* Reserve 0-filled space for the blockmap body in the backing file. */
+ file_end = incfs_get_end_offset(bfc->bc_file);
+ result = append_zeros(bfc, map_size);
+ if (result)
+ return result;
+
+ /* Write blockmap metadata record pointing to the body written above. */
+ blockmap.m_base_offset = cpu_to_le64(file_end);
+ result = append_md_to_backing_file(bfc, &blockmap.m_header);
+ if (result)
+ /* Error, rollback file changes */
+ truncate_backing_file(bfc, file_end);
+
+ return result;
+}
+
+int incfs_write_signature_to_backing_file(struct backing_file_context *bfc,
+ struct mem_range sig, u32 tree_size,
+ loff_t *tree_offset, loff_t *sig_offset)
+{
+ struct incfs_file_signature sg = {};
+ int result = 0;
+ loff_t rollback_pos = 0;
+ loff_t tree_area_pos = 0;
+ size_t alignment = 0;
+
+ if (!bfc)
+ return -EFAULT;
+
+ LOCK_REQUIRED(bfc->bc_mutex);
+
+ rollback_pos = incfs_get_end_offset(bfc->bc_file);
+
+ sg.sg_header.h_md_entry_type = INCFS_MD_SIGNATURE;
+ sg.sg_header.h_record_size = cpu_to_le16(sizeof(sg));
+ sg.sg_header.h_next_md_offset = cpu_to_le64(0);
+ if (sig.data != NULL && sig.len > 0) {
+ sg.sg_sig_size = cpu_to_le32(sig.len);
+ sg.sg_sig_offset = cpu_to_le64(rollback_pos);
+
+ result = write_to_bf(bfc, sig.data, sig.len, rollback_pos);
+ if (result)
+ goto err;
+ }
+
+ tree_area_pos = incfs_get_end_offset(bfc->bc_file);
+ if (tree_size > 0) {
+ if (tree_size > 5 * INCFS_DATA_FILE_BLOCK_SIZE) {
+ /*
+ * If hash tree is big enough, it makes sense to
+ * align in the backing file for faster access.
+ */
+ loff_t offset = round_up(tree_area_pos, PAGE_SIZE);
+
+ alignment = offset - tree_area_pos;
+ tree_area_pos = offset;
+ }
+
+ /*
+ * If root hash is not the only hash in the tree.
+ * reserve 0-filled space for the tree.
+ */
+ result = append_zeros(bfc, tree_size + alignment);
+ if (result)
+ goto err;
+
+ sg.sg_hash_tree_size = cpu_to_le32(tree_size);
+ sg.sg_hash_tree_offset = cpu_to_le64(tree_area_pos);
+ }
+
+ /* Write a hash tree metadata record pointing to the hash tree above. */
+ result = append_md_to_backing_file(bfc, &sg.sg_header);
+err:
+ if (result)
+ /* Error, rollback file changes */
+ truncate_backing_file(bfc, rollback_pos);
+ else {
+ if (tree_offset)
+ *tree_offset = tree_area_pos;
+ if (sig_offset)
+ *sig_offset = rollback_pos;
+ }
+
+ return result;
+}
+
+static int write_new_status_to_backing_file(struct backing_file_context *bfc,
+ u32 data_blocks_written,
+ u32 hash_blocks_written)
+{
+ int result;
+ loff_t rollback_pos;
+ struct incfs_status is = {
+ .is_header = {
+ .h_md_entry_type = INCFS_MD_STATUS,
+ .h_record_size = cpu_to_le16(sizeof(is)),
+ },
+ .is_data_blocks_written = cpu_to_le32(data_blocks_written),
+ .is_hash_blocks_written = cpu_to_le32(hash_blocks_written),
+ };
+
+ LOCK_REQUIRED(bfc->bc_mutex);
+ rollback_pos = incfs_get_end_offset(bfc->bc_file);
+ result = append_md_to_backing_file(bfc, &is.is_header);
+ if (result)
+ truncate_backing_file(bfc, rollback_pos);
+
+ return result;
+}
+
+int incfs_write_status_to_backing_file(struct backing_file_context *bfc,
+ loff_t status_offset,
+ u32 data_blocks_written,
+ u32 hash_blocks_written)
+{
+ struct incfs_status is;
+ int result;
+
+ if (!bfc)
+ return -EFAULT;
+
+ if (status_offset == 0)
+ return write_new_status_to_backing_file(bfc,
+ data_blocks_written, hash_blocks_written);
+
+ result = incfs_kread(bfc, &is, sizeof(is), status_offset);
+ if (result != sizeof(is))
+ return -EIO;
+
+ is.is_data_blocks_written = cpu_to_le32(data_blocks_written);
+ is.is_hash_blocks_written = cpu_to_le32(hash_blocks_written);
+ result = incfs_kwrite(bfc, &is, sizeof(is), status_offset);
+ if (result != sizeof(is))
+ return -EIO;
+
+ return 0;
+}
+
+int incfs_write_verity_signature_to_backing_file(
+ struct backing_file_context *bfc, struct mem_range signature,
+ loff_t *offset)
+{
+ struct incfs_file_verity_signature vs = {};
+ int result;
+ loff_t pos;
+
+ /* No verity signature section is equivalent to an empty section */
+ if (signature.data == NULL || signature.len == 0)
+ return 0;
+
+ pos = incfs_get_end_offset(bfc->bc_file);
+
+ vs = (struct incfs_file_verity_signature) {
+ .vs_header = (struct incfs_md_header) {
+ .h_md_entry_type = INCFS_MD_VERITY_SIGNATURE,
+ .h_record_size = cpu_to_le16(sizeof(vs)),
+ .h_next_md_offset = cpu_to_le64(0),
+ },
+ .vs_size = cpu_to_le32(signature.len),
+ .vs_offset = cpu_to_le64(pos),
+ };
+
+ result = write_to_bf(bfc, signature.data, signature.len, pos);
+ if (result)
+ goto err;
+
+ result = append_md_to_backing_file(bfc, &vs.vs_header);
+ if (result)
+ goto err;
+
+ *offset = pos;
+err:
+ if (result)
+ /* Error, rollback file changes */
+ truncate_backing_file(bfc, pos);
+ return result;
+}
+
+/*
+ * Write a backing file header
+ * It should always be called only on empty file.
+ * fh.fh_first_md_offset is 0 for now, but will be updated
+ * once first metadata record is added.
+ */
+int incfs_write_fh_to_backing_file(struct backing_file_context *bfc,
+ incfs_uuid_t *uuid, u64 file_size)
+{
+ struct incfs_file_header fh = {};
+ loff_t file_pos = 0;
+
+ if (!bfc)
+ return -EFAULT;
+
+ fh.fh_magic = cpu_to_le64(INCFS_MAGIC_NUMBER);
+ fh.fh_version = cpu_to_le64(INCFS_FORMAT_CURRENT_VER);
+ fh.fh_header_size = cpu_to_le16(sizeof(fh));
+ fh.fh_first_md_offset = cpu_to_le64(0);
+ fh.fh_data_block_size = cpu_to_le16(INCFS_DATA_FILE_BLOCK_SIZE);
+
+ fh.fh_file_size = cpu_to_le64(file_size);
+ fh.fh_uuid = *uuid;
+
+ LOCK_REQUIRED(bfc->bc_mutex);
+
+ file_pos = incfs_get_end_offset(bfc->bc_file);
+ if (file_pos != 0)
+ return -EEXIST;
+
+ return write_to_bf(bfc, &fh, sizeof(fh), file_pos);
+}
+
+/*
+ * Write a backing file header for a mapping file
+ * It should always be called only on empty file.
+ */
+int incfs_write_mapping_fh_to_backing_file(struct backing_file_context *bfc,
+ incfs_uuid_t *uuid, u64 file_size, u64 offset)
+{
+ struct incfs_file_header fh = {};
+ loff_t file_pos = 0;
+
+ if (!bfc)
+ return -EFAULT;
+
+ fh.fh_magic = cpu_to_le64(INCFS_MAGIC_NUMBER);
+ fh.fh_version = cpu_to_le64(INCFS_FORMAT_CURRENT_VER);
+ fh.fh_header_size = cpu_to_le16(sizeof(fh));
+ fh.fh_original_offset = cpu_to_le64(offset);
+ fh.fh_data_block_size = cpu_to_le16(INCFS_DATA_FILE_BLOCK_SIZE);
+
+ fh.fh_mapped_file_size = cpu_to_le64(file_size);
+ fh.fh_original_uuid = *uuid;
+ fh.fh_flags = cpu_to_le32(INCFS_FILE_MAPPED);
+
+ LOCK_REQUIRED(bfc->bc_mutex);
+
+ file_pos = incfs_get_end_offset(bfc->bc_file);
+ if (file_pos != 0)
+ return -EEXIST;
+
+ return write_to_bf(bfc, &fh, sizeof(fh), file_pos);
+}
+
+/* Write a given data block and update file's blockmap to point it. */
+int incfs_write_data_block_to_backing_file(struct backing_file_context *bfc,
+ struct mem_range block, int block_index,
+ loff_t bm_base_off, u16 flags)
+{
+ struct incfs_blockmap_entry bm_entry = {};
+ int result = 0;
+ loff_t data_offset = 0;
+ loff_t bm_entry_off =
+ bm_base_off + sizeof(struct incfs_blockmap_entry) * block_index;
+
+ if (!bfc)
+ return -EFAULT;
+
+ if (block.len >= (1 << 16) || block_index < 0)
+ return -EINVAL;
+
+ LOCK_REQUIRED(bfc->bc_mutex);
+
+ data_offset = incfs_get_end_offset(bfc->bc_file);
+ if (data_offset <= bm_entry_off) {
+ /* Blockmap entry is beyond the file's end. It is not normal. */
+ return -EINVAL;
+ }
+
+ /* Write the block data at the end of the backing file. */
+ result = write_to_bf(bfc, block.data, block.len, data_offset);
+ if (result)
+ return result;
+
+ /* Update the blockmap to point to the newly written data. */
+ bm_entry.me_data_offset_lo = cpu_to_le32((u32)data_offset);
+ bm_entry.me_data_offset_hi = cpu_to_le16((u16)(data_offset >> 32));
+ bm_entry.me_data_size = cpu_to_le16((u16)block.len);
+ bm_entry.me_flags = cpu_to_le16(flags);
+
+ return write_to_bf(bfc, &bm_entry, sizeof(bm_entry),
+ bm_entry_off);
+}
+
+int incfs_write_hash_block_to_backing_file(struct backing_file_context *bfc,
+ struct mem_range block,
+ int block_index,
+ loff_t hash_area_off,
+ loff_t bm_base_off,
+ loff_t file_size)
+{
+ struct incfs_blockmap_entry bm_entry = {};
+ int result;
+ loff_t data_offset = 0;
+ loff_t file_end = 0;
+ loff_t bm_entry_off =
+ bm_base_off +
+ sizeof(struct incfs_blockmap_entry) *
+ (block_index + get_blocks_count_for_size(file_size));
+
+ if (!bfc)
+ return -EFAULT;
+
+ LOCK_REQUIRED(bfc->bc_mutex);
+
+ data_offset = hash_area_off + block_index * INCFS_DATA_FILE_BLOCK_SIZE;
+ file_end = incfs_get_end_offset(bfc->bc_file);
+ if (data_offset + block.len > file_end) {
+ /* Block is located beyond the file's end. It is not normal. */
+ return -EINVAL;
+ }
+
+ result = write_to_bf(bfc, block.data, block.len, data_offset);
+ if (result)
+ return result;
+
+ bm_entry.me_data_offset_lo = cpu_to_le32((u32)data_offset);
+ bm_entry.me_data_offset_hi = cpu_to_le16((u16)(data_offset >> 32));
+ bm_entry.me_data_size = cpu_to_le16(INCFS_DATA_FILE_BLOCK_SIZE);
+
+ return write_to_bf(bfc, &bm_entry, sizeof(bm_entry), bm_entry_off);
+}
+
+int incfs_read_blockmap_entry(struct backing_file_context *bfc, int block_index,
+ loff_t bm_base_off,
+ struct incfs_blockmap_entry *bm_entry)
+{
+ int error = incfs_read_blockmap_entries(bfc, bm_entry, block_index, 1,
+ bm_base_off);
+
+ if (error < 0)
+ return error;
+
+ if (error == 0)
+ return -EIO;
+
+ if (error != 1)
+ return -EFAULT;
+
+ return 0;
+}
+
+int incfs_read_blockmap_entries(struct backing_file_context *bfc,
+ struct incfs_blockmap_entry *entries,
+ int start_index, int blocks_number,
+ loff_t bm_base_off)
+{
+ loff_t bm_entry_off =
+ bm_base_off + sizeof(struct incfs_blockmap_entry) * start_index;
+ const size_t bytes_to_read = sizeof(struct incfs_blockmap_entry)
+ * blocks_number;
+ int result = 0;
+
+ if (!bfc || !entries)
+ return -EFAULT;
+
+ if (start_index < 0 || bm_base_off <= 0)
+ return -ENODATA;
+
+ result = incfs_kread(bfc, entries, bytes_to_read, bm_entry_off);
+ if (result < 0)
+ return result;
+ return result / sizeof(*entries);
+}
+
+int incfs_read_file_header(struct backing_file_context *bfc,
+ loff_t *first_md_off, incfs_uuid_t *uuid,
+ u64 *file_size, u32 *flags)
+{
+ ssize_t bytes_read = 0;
+ struct incfs_file_header fh = {};
+
+ if (!bfc || !first_md_off)
+ return -EFAULT;
+
+ bytes_read = incfs_kread(bfc, &fh, sizeof(fh), 0);
+ if (bytes_read < 0)
+ return bytes_read;
+
+ if (bytes_read < sizeof(fh))
+ return -EBADMSG;
+
+ if (le64_to_cpu(fh.fh_magic) != INCFS_MAGIC_NUMBER)
+ return -EILSEQ;
+
+ if (le64_to_cpu(fh.fh_version) > INCFS_FORMAT_CURRENT_VER)
+ return -EILSEQ;
+
+ if (le16_to_cpu(fh.fh_data_block_size) != INCFS_DATA_FILE_BLOCK_SIZE)
+ return -EILSEQ;
+
+ if (le16_to_cpu(fh.fh_header_size) != sizeof(fh))
+ return -EILSEQ;
+
+ if (first_md_off)
+ *first_md_off = le64_to_cpu(fh.fh_first_md_offset);
+ if (uuid)
+ *uuid = fh.fh_uuid;
+ if (file_size)
+ *file_size = le64_to_cpu(fh.fh_file_size);
+ if (flags)
+ *flags = le32_to_cpu(fh.fh_flags);
+ return 0;
+}
+
+/*
+ * Read through metadata records from the backing file one by one
+ * and call provided metadata handlers.
+ */
+int incfs_read_next_metadata_record(struct backing_file_context *bfc,
+ struct metadata_handler *handler)
+{
+ const ssize_t max_md_size = INCFS_MAX_METADATA_RECORD_SIZE;
+ ssize_t bytes_read = 0;
+ size_t md_record_size = 0;
+ loff_t next_record = 0;
+ int res = 0;
+ struct incfs_md_header *md_hdr = NULL;
+
+ if (!bfc || !handler)
+ return -EFAULT;
+
+ if (handler->md_record_offset == 0)
+ return -EPERM;
+
+ memset(&handler->md_buffer, 0, max_md_size);
+ bytes_read = incfs_kread(bfc, &handler->md_buffer, max_md_size,
+ handler->md_record_offset);
+ if (bytes_read < 0)
+ return bytes_read;
+ if (bytes_read < sizeof(*md_hdr))
+ return -EBADMSG;
+
+ md_hdr = &handler->md_buffer.md_header;
+ next_record = le64_to_cpu(md_hdr->h_next_md_offset);
+ md_record_size = le16_to_cpu(md_hdr->h_record_size);
+
+ if (md_record_size > max_md_size) {
+ pr_warn("incfs: The record is too large. Size: %zu",
+ md_record_size);
+ return -EBADMSG;
+ }
+
+ if (bytes_read < md_record_size) {
+ pr_warn("incfs: The record hasn't been fully read.");
+ return -EBADMSG;
+ }
+
+ if (next_record <= handler->md_record_offset && next_record != 0) {
+ pr_warn("incfs: Next record (%lld) points back in file.",
+ next_record);
+ return -EBADMSG;
+ }
+
+ switch (md_hdr->h_md_entry_type) {
+ case INCFS_MD_NONE:
+ break;
+ case INCFS_MD_BLOCK_MAP:
+ if (handler->handle_blockmap)
+ res = handler->handle_blockmap(
+ &handler->md_buffer.blockmap, handler);
+ break;
+ case INCFS_MD_FILE_ATTR:
+ /*
+ * File attrs no longer supported, ignore section for
+ * compatibility
+ */
+ break;
+ case INCFS_MD_SIGNATURE:
+ if (handler->handle_signature)
+ res = handler->handle_signature(
+ &handler->md_buffer.signature, handler);
+ break;
+ case INCFS_MD_STATUS:
+ if (handler->handle_status)
+ res = handler->handle_status(
+ &handler->md_buffer.status, handler);
+ break;
+ case INCFS_MD_VERITY_SIGNATURE:
+ if (handler->handle_verity_signature)
+ res = handler->handle_verity_signature(
+ &handler->md_buffer.verity_signature, handler);
+ break;
+ default:
+ res = -ENOTSUPP;
+ break;
+ }
+
+ if (!res) {
+ if (next_record == 0) {
+ /*
+ * Zero offset for the next record means that the last
+ * metadata record has just been processed.
+ */
+ bfc->bc_last_md_record_offset =
+ handler->md_record_offset;
+ }
+ handler->md_prev_record_offset = handler->md_record_offset;
+ handler->md_record_offset = next_record;
+ }
+ return res;
+}
+
+ssize_t incfs_kread(struct backing_file_context *bfc, void *buf, size_t size,
+ loff_t pos)
+{
+ const struct cred *old_cred = override_creds(bfc->bc_cred);
+ int ret = kernel_read(bfc->bc_file, buf, size, &pos);
+
+ revert_creds(old_cred);
+ return ret;
+}
+
+ssize_t incfs_kwrite(struct backing_file_context *bfc, const void *buf,
+ size_t size, loff_t pos)
+{
+ const struct cred *old_cred = override_creds(bfc->bc_cred);
+ int ret = kernel_write(bfc->bc_file, buf, size, &pos);
+
+ revert_creds(old_cred);
+ return ret;
+}