ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/fs/incfs/format.h b/marvell/linux/fs/incfs/format.h
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+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2018 Google LLC
+ */
+
+/*
+ * Overview
+ * --------
+ * The backbone of the incremental-fs ondisk format is an append only linked
+ * list of metadata blocks. Each metadata block contains an offset of the next
+ * one. These blocks describe files and directories on the
+ * file system. They also represent actions of adding and removing file names
+ * (hard links).
+ *
+ * Every time incremental-fs instance is mounted, it reads through this list
+ * to recreate filesystem's state in memory. An offset of the first record in
+ * the metadata list is stored in the superblock at the beginning of the backing
+ * file.
+ *
+ * Most of the backing file is taken by data areas and blockmaps.
+ * Since data blocks can be compressed and have different sizes,
+ * single per-file data area can't be pre-allocated. That's why blockmaps are
+ * needed in order to find a location and size of each data block in
+ * the backing file. Each time a file is created, a corresponding block map is
+ * allocated to store future offsets of data blocks.
+ *
+ * Whenever a data block is given by data loader to incremental-fs:
+ * - A data area with the given block is appended to the end of
+ * the backing file.
+ * - A record in the blockmap for the given block index is updated to reflect
+ * its location, size, and compression algorithm.
+
+ * Metadata records
+ * ----------------
+ * incfs_blockmap - metadata record that specifies size and location
+ * of a blockmap area for a given file. This area
+ * contains an array of incfs_blockmap_entry-s.
+ * incfs_file_signature - metadata record that specifies where file signature
+ * and its hash tree can be found in the backing file.
+ *
+ * incfs_file_attr - metadata record that specifies where additional file
+ * attributes blob can be found.
+ *
+ * Metadata header
+ * ---------------
+ * incfs_md_header - header of a metadata record. It's always a part
+ * of other structures and served purpose of metadata
+ * bookkeeping.
+ *
+ * +-----------------------------------------------+ ^
+ * | incfs_md_header | |
+ * | 1. type of body(BLOCKMAP, FILE_ATTR..) | |
+ * | 2. size of the whole record header + body | |
+ * | 3. CRC the whole record header + body | |
+ * | 4. offset of the previous md record |]------+
+ * | 5. offset of the next md record (md link) |]---+
+ * +-----------------------------------------------+ |
+ * | Metadata record body with useful data | |
+ * +-----------------------------------------------+ |
+ * +--->
+ *
+ * Other ondisk structures
+ * -----------------------
+ * incfs_super_block - backing file header
+ * incfs_blockmap_entry - a record in a blockmap area that describes size
+ * and location of a data block.
+ * Data blocks dont have any particular structure, they are written to the
+ * backing file in a raw form as they come from a data loader.
+ *
+ * Backing file layout
+ * -------------------
+ *
+ *
+ * +-------------------------------------------+
+ * | incfs_file_header |]---+
+ * +-------------------------------------------+ |
+ * | metadata |<---+
+ * | incfs_file_signature |]---+
+ * +-------------------------------------------+ |
+ * ......................... |
+ * +-------------------------------------------+ | metadata
+ * +------->| blockmap area | | list links
+ * | | [incfs_blockmap_entry] | |
+ * | | [incfs_blockmap_entry] | |
+ * | | [incfs_blockmap_entry] | |
+ * | +--[| [incfs_blockmap_entry] | |
+ * | | | [incfs_blockmap_entry] | |
+ * | | | [incfs_blockmap_entry] | |
+ * | | +-------------------------------------------+ |
+ * | | ......................... |
+ * | | +-------------------------------------------+ |
+ * | | | metadata |<---+
+ * +----|--[| incfs_blockmap |]---+
+ * | +-------------------------------------------+ |
+ * | ......................... |
+ * | +-------------------------------------------+ |
+ * +-->| data block | |
+ * +-------------------------------------------+ |
+ * ......................... |
+ * +-------------------------------------------+ |
+ * | metadata |<---+
+ * | incfs_file_attr |
+ * +-------------------------------------------+
+ */
+#ifndef _INCFS_FORMAT_H
+#define _INCFS_FORMAT_H
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <uapi/linux/incrementalfs.h>
+
+#include "internal.h"
+
+#define INCFS_MAX_NAME_LEN 255
+#define INCFS_FORMAT_V1 1
+#define INCFS_FORMAT_CURRENT_VER INCFS_FORMAT_V1
+
+enum incfs_metadata_type {
+ INCFS_MD_NONE = 0,
+ INCFS_MD_BLOCK_MAP = 1,
+ INCFS_MD_FILE_ATTR = 2,
+ INCFS_MD_SIGNATURE = 3,
+ INCFS_MD_STATUS = 4,
+ INCFS_MD_VERITY_SIGNATURE = 5,
+};
+
+enum incfs_file_header_flags {
+ INCFS_FILE_MAPPED = 1 << 1,
+};
+
+/* Header included at the beginning of all metadata records on the disk. */
+struct incfs_md_header {
+ __u8 h_md_entry_type;
+
+ /*
+ * Size of the metadata record.
+ * (e.g. inode, dir entry etc) not just this struct.
+ */
+ __le16 h_record_size;
+
+ /*
+ * Was: CRC32 of the metadata record.
+ * (e.g. inode, dir entry etc) not just this struct.
+ */
+ __le32 h_unused1;
+
+ /* Offset of the next metadata entry if any */
+ __le64 h_next_md_offset;
+
+ /* Was: Offset of the previous metadata entry if any */
+ __le64 h_unused2;
+
+} __packed;
+
+/* Backing file header */
+struct incfs_file_header {
+ /* Magic number: INCFS_MAGIC_NUMBER */
+ __le64 fh_magic;
+
+ /* Format version: INCFS_FORMAT_CURRENT_VER */
+ __le64 fh_version;
+
+ /* sizeof(incfs_file_header) */
+ __le16 fh_header_size;
+
+ /* INCFS_DATA_FILE_BLOCK_SIZE */
+ __le16 fh_data_block_size;
+
+ /* File flags, from incfs_file_header_flags */
+ __le32 fh_flags;
+
+ union {
+ /* Standard incfs file */
+ struct {
+ /* Offset of the first metadata record */
+ __le64 fh_first_md_offset;
+
+ /* Full size of the file's content */
+ __le64 fh_file_size;
+
+ /* File uuid */
+ incfs_uuid_t fh_uuid;
+ };
+
+ /* Mapped file - INCFS_FILE_MAPPED set in fh_flags */
+ struct {
+ /* Offset in original file */
+ __le64 fh_original_offset;
+
+ /* Full size of the file's content */
+ __le64 fh_mapped_file_size;
+
+ /* Original file's uuid */
+ incfs_uuid_t fh_original_uuid;
+ };
+ };
+} __packed;
+
+enum incfs_block_map_entry_flags {
+ INCFS_BLOCK_COMPRESSED_LZ4 = 1,
+ INCFS_BLOCK_COMPRESSED_ZSTD = 2,
+
+ /* Reserve 3 bits for compression alg */
+ INCFS_BLOCK_COMPRESSED_MASK = 7,
+};
+
+/* Block map entry pointing to an actual location of the data block. */
+struct incfs_blockmap_entry {
+ /* Offset of the actual data block. Lower 32 bits */
+ __le32 me_data_offset_lo;
+
+ /* Offset of the actual data block. Higher 16 bits */
+ __le16 me_data_offset_hi;
+
+ /* How many bytes the data actually occupies in the backing file */
+ __le16 me_data_size;
+
+ /* Block flags from incfs_block_map_entry_flags */
+ __le16 me_flags;
+} __packed;
+
+/* Metadata record for locations of file blocks. Type = INCFS_MD_BLOCK_MAP */
+struct incfs_blockmap {
+ struct incfs_md_header m_header;
+
+ /* Base offset of the array of incfs_blockmap_entry */
+ __le64 m_base_offset;
+
+ /* Size of the map entry array in blocks */
+ __le32 m_block_count;
+} __packed;
+
+/*
+ * Metadata record for file signature. Type = INCFS_MD_SIGNATURE
+ *
+ * The signature stored here is the APK V4 signature data blob. See the
+ * definition of incfs_new_file_args::signature_info for an explanation of this
+ * blob. Specifically, it contains the root hash, but it does *not* contain
+ * anything that the kernel treats as a signature.
+ *
+ * When FS_IOC_ENABLE_VERITY is called on a file without this record, an APK V4
+ * signature blob and a hash tree are added to the file, and then this metadata
+ * record is created to record their locations.
+ */
+struct incfs_file_signature {
+ struct incfs_md_header sg_header;
+
+ __le32 sg_sig_size; /* The size of the signature. */
+
+ __le64 sg_sig_offset; /* Signature's offset in the backing file */
+
+ __le32 sg_hash_tree_size; /* The size of the hash tree. */
+
+ __le64 sg_hash_tree_offset; /* Hash tree offset in the backing file */
+} __packed;
+
+/* In memory version of above */
+struct incfs_df_signature {
+ u32 sig_size;
+ u64 sig_offset;
+ u32 hash_size;
+ u64 hash_offset;
+};
+
+struct incfs_status {
+ struct incfs_md_header is_header;
+
+ __le32 is_data_blocks_written; /* Number of data blocks written */
+
+ __le32 is_hash_blocks_written; /* Number of hash blocks written */
+
+ __le32 is_dummy[6]; /* Spare fields */
+} __packed;
+
+/*
+ * Metadata record for verity signature. Type = INCFS_MD_VERITY_SIGNATURE
+ *
+ * This record will only exist for verity-enabled files with signatures. Verity
+ * enabled files without signatures do not have this record. This signature is
+ * checked by fs-verity identically to any other fs-verity signature.
+ */
+struct incfs_file_verity_signature {
+ struct incfs_md_header vs_header;
+
+ /* The size of the signature */
+ __le32 vs_size;
+
+ /* Signature's offset in the backing file */
+ __le64 vs_offset;
+} __packed;
+
+/* In memory version of above */
+struct incfs_df_verity_signature {
+ u32 size;
+ u64 offset;
+};
+
+/* State of the backing file. */
+struct backing_file_context {
+ /* Protects writes to bc_file */
+ struct mutex bc_mutex;
+
+ /* File object to read data from */
+ struct file *bc_file;
+
+ /*
+ * Offset of the last known metadata record in the backing file.
+ * 0 means there are no metadata records.
+ */
+ loff_t bc_last_md_record_offset;
+
+ /*
+ * Credentials to set before reads/writes
+ * Note that this is a pointer to the mount_info mi_owner field so
+ * there is no need to get/put the creds
+ */
+ const struct cred *bc_cred;
+};
+
+struct metadata_handler {
+ loff_t md_record_offset;
+ loff_t md_prev_record_offset;
+ void *context;
+
+ union {
+ struct incfs_md_header md_header;
+ struct incfs_blockmap blockmap;
+ struct incfs_file_signature signature;
+ struct incfs_status status;
+ struct incfs_file_verity_signature verity_signature;
+ } md_buffer;
+
+ int (*handle_blockmap)(struct incfs_blockmap *bm,
+ struct metadata_handler *handler);
+ int (*handle_signature)(struct incfs_file_signature *sig,
+ struct metadata_handler *handler);
+ int (*handle_status)(struct incfs_status *sig,
+ struct metadata_handler *handler);
+ int (*handle_verity_signature)(struct incfs_file_verity_signature *s,
+ struct metadata_handler *handler);
+};
+#define INCFS_MAX_METADATA_RECORD_SIZE \
+ FIELD_SIZEOF(struct metadata_handler, md_buffer)
+
+/* Backing file context management */
+struct mount_info;
+struct backing_file_context *incfs_alloc_bfc(struct mount_info *mi,
+ struct file *backing_file);
+
+void incfs_free_bfc(struct backing_file_context *bfc);
+
+/* Writing stuff */
+int incfs_write_blockmap_to_backing_file(struct backing_file_context *bfc,
+ u32 block_count);
+
+int incfs_write_fh_to_backing_file(struct backing_file_context *bfc,
+ incfs_uuid_t *uuid, u64 file_size);
+
+int incfs_write_mapping_fh_to_backing_file(struct backing_file_context *bfc,
+ incfs_uuid_t *uuid, u64 file_size, u64 offset);
+
+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);
+
+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);
+
+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);
+
+int incfs_write_status_to_backing_file(struct backing_file_context *bfc,
+ loff_t status_offset,
+ u32 data_blocks_written,
+ u32 hash_blocks_written);
+int incfs_write_verity_signature_to_backing_file(
+ struct backing_file_context *bfc, struct mem_range signature,
+ loff_t *offset);
+
+/* Reading stuff */
+int incfs_read_file_header(struct backing_file_context *bfc,
+ loff_t *first_md_off, incfs_uuid_t *uuid,
+ u64 *file_size, u32 *flags);
+
+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 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);
+
+int incfs_read_next_metadata_record(struct backing_file_context *bfc,
+ struct metadata_handler *handler);
+
+ssize_t incfs_kread(struct backing_file_context *bfc, void *buf, size_t size,
+ loff_t pos);
+ssize_t incfs_kwrite(struct backing_file_context *bfc, const void *buf,
+ size_t size, loff_t pos);
+
+#endif /* _INCFS_FORMAT_H */