[RFC PATCH 06/76] ssdfs: segment header + log footer operations

[Viacheslav Dubeyko <slava@dubeyko.com>]

SSDFS is Log-structured File System (LFS). It means that volume
is a sequence of segments that can contain one or several erase
blocks. Any write operation into erase block is a creation of log.
And content of every erase block is a sequence of logs. Log can be
full or partial. Full log starts by header and it is finished by footer.
The size of full log is fixed and it is defined during mkfs phase.
However, tunefs tool can change this value. But if commit operation
has not enough data to prepare the full log, then partial log is created.
Partial log starts with partial log header and it hasn't footer.
The partial log can be imagined like mixture of segment header and
log footer.

Segment header can be considered like static superblock info.
It contains metadata that not changed at all after volume
creation (logical block size, for example) or changed rarely
(number of segments in the volume, for example). Log footer
can be considered like dynamic part of superblock because
it contains frequently updated metadata (for example, root
node of inodes b-tree).

Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
CC: Viacheslav Dubeyko <viacheslav.dubeyko@bytedance.com>
CC: Luka Perkov <luka.perkov@sartura.hr>
CC: Bruno Banelli <bruno.banelli@sartura.hr>
---
 fs/ssdfs/log_footer.c    |  901 +++++++++++++++++++++++++++
 fs/ssdfs/volume_header.c | 1256 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 2157 insertions(+)
 create mode 100644 fs/ssdfs/log_footer.c
 create mode 100644 fs/ssdfs/volume_header.c

diff --git a/fs/ssdfs/log_footer.c b/fs/ssdfs/log_footer.c
new file mode 100644
index 000000000000..f56a268f310e
--- /dev/null
+++ b/fs/ssdfs/log_footer.c
@@ -0,0 +1,901 @@
+// SPDX-License-Identifier: BSD-3-Clause-Clear
+/*
+ * SSDFS -- SSD-oriented File System.
+ *
+ * fs/ssdfs/log_footer.c - operations with log footer.
+ *
+ * Copyright (c) 2014-2019 HGST, a Western Digital Company.
+ *              http://www.hgst.com/
+ * Copyright (c) 2014-2023 Viacheslav Dubeyko <slava@dubeyko.com>
+ *              http://www.ssdfs.org/
+ *
+ * (C) Copyright 2014-2019, HGST, Inc., All rights reserved.
+ *
+ * Created by HGST, San Jose Research Center, Storage Architecture Group
+ *
+ * Authors: Viacheslav Dubeyko <slava@dubeyko.com>
+ *
+ * Acknowledgement: Cyril Guyot
+ *                  Zvonimir Bandic
+ */
+
+#include <linux/kernel.h>
+#include <linux/rwsem.h>
+#include <linux/pagevec.h>
+
+#include "peb_mapping_queue.h"
+#include "peb_mapping_table_cache.h"
+#include "ssdfs.h"
+#include "segment_bitmap.h"
+#include "offset_translation_table.h"
+#include "page_array.h"
+#include "page_vector.h"
+#include "peb_container.h"
+#include "segment.h"
+#include "current_segment.h"
+
+#include <trace/events/ssdfs.h>
+
+/*
+ * __is_ssdfs_log_footer_magic_valid() - check log footer's magic
+ * @magic: pointer on magic value
+ */
+bool __is_ssdfs_log_footer_magic_valid(struct ssdfs_signature *magic)
+{
+	return le16_to_cpu(magic->key) == SSDFS_LOG_FOOTER_MAGIC;
+}
+
+/*
+ * is_ssdfs_log_footer_magic_valid() - check log footer's magic
+ * @footer: log footer
+ */
+bool is_ssdfs_log_footer_magic_valid(struct ssdfs_log_footer *footer)
+{
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(!footer);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	return __is_ssdfs_log_footer_magic_valid(&footer->volume_state.magic);
+}
+
+/*
+ * is_ssdfs_log_footer_csum_valid() - check log footer's checksum
+ * @buf: buffer with log footer
+ * @size: size of buffer in bytes
+ */
+bool is_ssdfs_log_footer_csum_valid(void *buf, size_t buf_size)
+{
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(!buf);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	return is_csum_valid(&SSDFS_LF(buf)->volume_state.check, buf, buf_size);
+}
+
+/*
+ * is_ssdfs_volume_state_info_consistent() - check volume state consistency
+ * @fsi: pointer on shared file system object
+ * @buf: log header
+ * @footer: log footer
+ * @dev_size: partition size in bytes
+ *
+ * RETURN:
+ * [true]  - volume state metadata is consistent.
+ * [false] - volume state metadata is corrupted.
+ */
+bool is_ssdfs_volume_state_info_consistent(struct ssdfs_fs_info *fsi,
+					   void *buf,
+					   struct ssdfs_log_footer *footer,
+					   u64 dev_size)
+{
+	struct ssdfs_signature *magic;
+	u64 nsegs;
+	u64 free_pages;
+	u8 log_segsize = U8_MAX;
+	u32 seg_size = U32_MAX;
+	u32 page_size = U32_MAX;
+	u64 cno = U64_MAX;
+	u16 log_pages = U16_MAX;
+	u32 log_bytes = U32_MAX;
+	u64 pages_count;
+	u32 pages_per_seg;
+	u32 remainder;
+	u16 fs_state;
+	u16 fs_errors;
+
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(!buf || !footer);
+
+	SSDFS_DBG("buf %p, footer %p, dev_size %llu\n",
+		  buf, footer, dev_size);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	magic = (struct ssdfs_signature *)buf;
+
+	if (!is_ssdfs_magic_valid(magic)) {
+		SSDFS_DBG("valid magic is not detected\n");
+		return -ERANGE;
+	}
+
+	if (__is_ssdfs_segment_header_magic_valid(magic)) {
+		struct ssdfs_segment_header *hdr;
+		struct ssdfs_volume_header *vh;
+
+		hdr = SSDFS_SEG_HDR(buf);
+		vh = SSDFS_VH(buf);
+
+		log_segsize = vh->log_segsize;
+		seg_size = 1 << vh->log_segsize;
+		page_size = 1 << vh->log_pagesize;
+		cno = le64_to_cpu(hdr->cno);
+		log_pages = le16_to_cpu(hdr->log_pages);
+	} else if (is_ssdfs_partial_log_header_magic_valid(magic)) {
+		struct ssdfs_partial_log_header *pl_hdr;
+
+		pl_hdr = SSDFS_PLH(buf);
+
+		log_segsize = pl_hdr->log_segsize;
+		seg_size = 1 << pl_hdr->log_segsize;
+		page_size = 1 << pl_hdr->log_pagesize;
+		cno = le64_to_cpu(pl_hdr->cno);
+		log_pages = le16_to_cpu(pl_hdr->log_pages);
+	} else {
+		SSDFS_DBG("log header is corrupted\n");
+		return -EIO;
+	}
+
+	nsegs = le64_to_cpu(footer->volume_state.nsegs);
+
+	if (nsegs == 0 || nsegs > (dev_size >> log_segsize)) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("invalid nsegs %llu, dev_size %llu, seg_size) %u\n",
+			  nsegs, dev_size, seg_size);
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	free_pages = le64_to_cpu(footer->volume_state.free_pages);
+
+	pages_count = div_u64_rem(dev_size, page_size, &remainder);
+	if (remainder) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("dev_size %llu is unaligned on page_size %u\n",
+			  dev_size, page_size);
+#endif /* CONFIG_SSDFS_DEBUG */
+	}
+
+	if (free_pages > pages_count) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("free_pages %llu is greater than pages_count %llu\n",
+			  free_pages, pages_count);
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	pages_per_seg = seg_size / page_size;
+	if (nsegs <= div_u64(free_pages, pages_per_seg)) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("invalid nsegs %llu, free_pages %llu, "
+			  "pages_per_seg %u\n",
+			  nsegs, free_pages, pages_per_seg);
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	if (cno > le64_to_cpu(footer->cno)) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("create_cno %llu is greater than write_cno %llu\n",
+			  cno, le64_to_cpu(footer->cno));
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	log_bytes = (u32)log_pages * fsi->pagesize;
+	if (le32_to_cpu(footer->log_bytes) > log_bytes) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("hdr log_bytes %u > footer log_bytes %u\n",
+			  log_bytes,
+			  le32_to_cpu(footer->log_bytes));
+#endif /* CONFIG_SSDFS_DEBUG */
+		return -EIO;
+	}
+
+	fs_state = le16_to_cpu(footer->volume_state.state);
+	if (fs_state > SSDFS_LAST_KNOWN_FS_STATE) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("unknown FS state %#x\n",
+			  fs_state);
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	fs_errors = le16_to_cpu(footer->volume_state.errors);
+	if (fs_errors > SSDFS_LAST_KNOWN_FS_ERROR) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("unknown FS error %#x\n",
+			  fs_errors);
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	return true;
+}
+
+/*
+ * ssdfs_check_log_footer() - check log footer consistency
+ * @fsi: pointer on shared file system object
+ * @buf: log header
+ * @footer: log footer
+ * @silent: show error or not?
+ *
+ * This function checks consistency of log footer.
+ *
+ * RETURN:
+ * [success] - log footer is consistent.
+ * [failure] - error code:
+ *
+ * %-ENODATA     - valid magic doesn't detected.
+ * %-EIO         - log footer is corrupted.
+ */
+int ssdfs_check_log_footer(struct ssdfs_fs_info *fsi,
+			   void *buf,
+			   struct ssdfs_log_footer *footer,
+			   bool silent)
+{
+	struct ssdfs_volume_state *vs;
+	size_t footer_size = sizeof(struct ssdfs_log_footer);
+	u64 dev_size;
+	bool major_magic_valid, minor_magic_valid;
+
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(!fsi || !buf || !footer);
+
+	SSDFS_DBG("fsi %p, buf %p, footer %p, silent %#x\n",
+		  fsi, buf, footer, silent);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	vs = SSDFS_VS(footer);
+
+	major_magic_valid = is_ssdfs_magic_valid(&vs->magic);
+	minor_magic_valid = is_ssdfs_log_footer_magic_valid(footer);
+
+	if (!major_magic_valid && !minor_magic_valid) {
+		if (!silent)
+			SSDFS_ERR("valid magic doesn't detected\n");
+		else
+			SSDFS_DBG("valid magic doesn't detected\n");
+		return -ENODATA;
+	} else if (!major_magic_valid) {
+		if (!silent)
+			SSDFS_ERR("invalid SSDFS magic signature\n");
+		else
+			SSDFS_DBG("invalid SSDFS magic signature\n");
+		return -EIO;
+	} else if (!minor_magic_valid) {
+		if (!silent)
+			SSDFS_ERR("invalid log footer magic signature\n");
+		else
+			SSDFS_DBG("invalid log footer magic signature\n");
+		return -EIO;
+	}
+
+	if (!is_ssdfs_log_footer_csum_valid(footer, footer_size)) {
+		if (!silent)
+			SSDFS_ERR("invalid checksum of log footer\n");
+		else
+			SSDFS_DBG("invalid checksum of log footer\n");
+		return -EIO;
+	}
+
+	dev_size = fsi->devops->device_size(fsi->sb);
+	if (!is_ssdfs_volume_state_info_consistent(fsi, buf,
+						   footer, dev_size)) {
+		if (!silent)
+			SSDFS_ERR("log footer is corrupted\n");
+		else
+			SSDFS_DBG("log footer is corrupted\n");
+		return -EIO;
+	}
+
+	if (le32_to_cpu(footer->log_flags) & ~SSDFS_LOG_FOOTER_FLAG_MASK) {
+		if (!silent) {
+			SSDFS_ERR("corrupted log_flags %#x\n",
+				  le32_to_cpu(footer->log_flags));
+		} else {
+			SSDFS_DBG("corrupted log_flags %#x\n",
+				  le32_to_cpu(footer->log_flags));
+		}
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/*
+ * ssdfs_read_unchecked_log_footer() - read log footer without check
+ * @fsi: pointer on shared file system object
+ * @peb_id: PEB identification number
+ * @bytes_off: offset inside PEB in bytes
+ * @buf: buffer for log footer
+ * @silent: show error or not?
+ * @log_pages: number of pages in the log
+ *
+ * This function reads log footer without
+ * the consistency check.
+ *
+ * RETURN:
+ * [success] - log footer is consistent.
+ * [failure] - error code:
+ *
+ * %-ENODATA     - valid magic doesn't detected.
+ * %-EIO         - log footer is corrupted.
+ */
+int ssdfs_read_unchecked_log_footer(struct ssdfs_fs_info *fsi,
+				    u64 peb_id, u32 bytes_off,
+				    void *buf, bool silent,
+				    u32 *log_pages)
+{
+	struct ssdfs_signature *magic;
+	struct ssdfs_log_footer *footer;
+	struct ssdfs_volume_state *vs;
+	size_t footer_size = sizeof(struct ssdfs_log_footer);
+	struct ssdfs_partial_log_header *pl_hdr;
+	size_t hdr_size = sizeof(struct ssdfs_partial_log_header);
+	bool major_magic_valid, minor_magic_valid;
+	int err;
+
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(!fsi || !fsi->devops->read);
+	BUG_ON(!buf || !log_pages);
+	BUG_ON(bytes_off >= (fsi->pages_per_peb * fsi->pagesize));
+
+	SSDFS_DBG("peb_id %llu, bytes_off %u, buf %p\n",
+		  peb_id, bytes_off, buf);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	*log_pages = U32_MAX;
+
+	err = ssdfs_unaligned_read_buffer(fsi, peb_id, bytes_off,
+					  buf, footer_size);
+	if (unlikely(err)) {
+		if (!silent) {
+			SSDFS_ERR("fail to read log footer: "
+				  "peb_id %llu, bytes_off %u, err %d\n",
+				  peb_id, bytes_off, err);
+		} else {
+#ifdef CONFIG_SSDFS_DEBUG
+			SSDFS_DBG("fail to read log footer: "
+				  "peb_id %llu, bytes_off %u, err %d\n",
+				  peb_id, bytes_off, err);
+#endif /* CONFIG_SSDFS_DEBUG */
+		}
+		return err;
+	}
+
+	magic = (struct ssdfs_signature *)buf;
+
+	if (!is_ssdfs_magic_valid(magic)) {
+		if (!silent)
+			SSDFS_ERR("valid magic is not detected\n");
+		else
+			SSDFS_DBG("valid magic is not detected\n");
+
+		return -ENODATA;
+	}
+
+	if (__is_ssdfs_log_footer_magic_valid(magic)) {
+		footer = SSDFS_LF(buf);
+		vs = SSDFS_VS(footer);
+
+		major_magic_valid = is_ssdfs_magic_valid(&vs->magic);
+		minor_magic_valid = is_ssdfs_log_footer_magic_valid(footer);
+
+		if (!major_magic_valid && !minor_magic_valid) {
+			if (!silent)
+				SSDFS_ERR("valid magic doesn't detected\n");
+			else
+				SSDFS_DBG("valid magic doesn't detected\n");
+			return -ENODATA;
+		} else if (!major_magic_valid) {
+			if (!silent)
+				SSDFS_ERR("invalid SSDFS magic signature\n");
+			else
+				SSDFS_DBG("invalid SSDFS magic signature\n");
+			return -EIO;
+		} else if (!minor_magic_valid) {
+			if (!silent)
+				SSDFS_ERR("invalid log footer magic\n");
+			else
+				SSDFS_DBG("invalid log footer magic\n");
+			return -EIO;
+		}
+
+		if (!is_ssdfs_log_footer_csum_valid(footer, footer_size)) {
+			if (!silent)
+				SSDFS_ERR("invalid checksum of log footer\n");
+			else
+				SSDFS_DBG("invalid checksum of log footer\n");
+			return -EIO;
+		}
+
+		*log_pages = le32_to_cpu(footer->log_bytes);
+		*log_pages /= fsi->pagesize;
+
+		if (*log_pages == 0 || *log_pages >= fsi->pages_per_peb) {
+			if (!silent)
+				SSDFS_ERR("invalid log pages %u\n", *log_pages);
+			else
+				SSDFS_DBG("invalid log pages %u\n", *log_pages);
+			return -EIO;
+		}
+	} else if (is_ssdfs_partial_log_header_magic_valid(magic)) {
+		pl_hdr = SSDFS_PLH(buf);
+
+		major_magic_valid = is_ssdfs_magic_valid(&pl_hdr->magic);
+		minor_magic_valid =
+			is_ssdfs_partial_log_header_magic_valid(&pl_hdr->magic);
+
+		if (!major_magic_valid && !minor_magic_valid) {
+			if (!silent)
+				SSDFS_ERR("valid magic doesn't detected\n");
+			else
+				SSDFS_DBG("valid magic doesn't detected\n");
+			return -ENODATA;
+		} else if (!major_magic_valid) {
+			if (!silent)
+				SSDFS_ERR("invalid SSDFS magic signature\n");
+			else
+				SSDFS_DBG("invalid SSDFS magic signature\n");
+			return -EIO;
+		} else if (!minor_magic_valid) {
+			if (!silent)
+				SSDFS_ERR("invalid partial log header magic\n");
+			else
+				SSDFS_DBG("invalid partial log header magic\n");
+			return -EIO;
+		}
+
+		if (!is_ssdfs_partial_log_header_csum_valid(pl_hdr, hdr_size)) {
+			if (!silent)
+				SSDFS_ERR("invalid checksum of footer\n");
+			else
+				SSDFS_DBG("invalid checksum of footer\n");
+			return -EIO;
+		}
+
+		*log_pages = le32_to_cpu(pl_hdr->log_bytes);
+		*log_pages /= fsi->pagesize;
+
+		if (*log_pages == 0 || *log_pages >= fsi->pages_per_peb) {
+			if (!silent)
+				SSDFS_ERR("invalid log pages %u\n", *log_pages);
+			else
+				SSDFS_DBG("invalid log pages %u\n", *log_pages);
+			return -EIO;
+		}
+	} else {
+		if (!silent) {
+			SSDFS_ERR("log footer is corrupted: "
+				  "peb_id %llu, bytes_off %u\n",
+				  peb_id, bytes_off);
+		} else {
+#ifdef CONFIG_SSDFS_DEBUG
+			SSDFS_DBG("log footer is corrupted: "
+				  "peb_id %llu, bytes_off %u\n",
+				  peb_id, bytes_off);
+#endif /* CONFIG_SSDFS_DEBUG */
+		}
+
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/*
+ * ssdfs_read_checked_log_footer() - read and check log footer
+ * @fsi: pointer on shared file system object
+ * @log_hdr: log header
+ * @peb_id: PEB identification number
+ * @bytes_off: offset inside PEB in bytes
+ * @buf: buffer for log footer
+ * @silent: show error or not?
+ *
+ * This function reads and checks consistency of log footer.
+ *
+ * RETURN:
+ * [success] - log footer is consistent.
+ * [failure] - error code:
+ *
+ * %-ENODATA     - valid magic doesn't detected.
+ * %-EIO         - log footer is corrupted.
+ */
+int ssdfs_read_checked_log_footer(struct ssdfs_fs_info *fsi, void *log_hdr,
+				  u64 peb_id, u32 bytes_off, void *buf,
+				  bool silent)
+{
+	struct ssdfs_signature *magic;
+	struct ssdfs_log_footer *footer;
+	struct ssdfs_partial_log_header *pl_hdr;
+	size_t footer_size = sizeof(struct ssdfs_log_footer);
+	int err;
+
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(!fsi || !fsi->devops->read);
+	BUG_ON(!log_hdr || !buf);
+	BUG_ON(bytes_off >= (fsi->pages_per_peb * fsi->pagesize));
+
+	SSDFS_DBG("peb_id %llu, bytes_off %u, buf %p\n",
+		  peb_id, bytes_off, buf);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	err = ssdfs_unaligned_read_buffer(fsi, peb_id, bytes_off,
+					  buf, footer_size);
+	if (unlikely(err)) {
+		if (!silent) {
+			SSDFS_ERR("fail to read log footer: "
+				  "peb_id %llu, bytes_off %u, err %d\n",
+				  peb_id, bytes_off, err);
+		} else {
+#ifdef CONFIG_SSDFS_DEBUG
+			SSDFS_DBG("fail to read log footer: "
+				  "peb_id %llu, bytes_off %u, err %d\n",
+				  peb_id, bytes_off, err);
+#endif /* CONFIG_SSDFS_DEBUG */
+		}
+		return err;
+	}
+
+	magic = (struct ssdfs_signature *)buf;
+
+	if (!is_ssdfs_magic_valid(magic)) {
+		if (!silent)
+			SSDFS_ERR("valid magic is not detected\n");
+		else
+			SSDFS_DBG("valid magic is not detected\n");
+
+		return -ENODATA;
+	}
+
+	if (__is_ssdfs_log_footer_magic_valid(magic)) {
+		footer = SSDFS_LF(buf);
+
+		err = ssdfs_check_log_footer(fsi, log_hdr, footer, silent);
+		if (err) {
+			if (!silent) {
+				SSDFS_ERR("log footer is corrupted: "
+					  "peb_id %llu, bytes_off %u, err %d\n",
+					  peb_id, bytes_off, err);
+			} else {
+#ifdef CONFIG_SSDFS_DEBUG
+				SSDFS_DBG("log footer is corrupted: "
+					  "peb_id %llu, bytes_off %u, err %d\n",
+					  peb_id, bytes_off, err);
+#endif /* CONFIG_SSDFS_DEBUG */
+			}
+			return err;
+		}
+	} else if (is_ssdfs_partial_log_header_magic_valid(magic)) {
+		pl_hdr = SSDFS_PLH(buf);
+
+		err = ssdfs_check_partial_log_header(fsi, pl_hdr, silent);
+		if (unlikely(err)) {
+			if (!silent) {
+				SSDFS_ERR("partial log header is corrupted: "
+					  "peb_id %llu, bytes_off %u\n",
+					  peb_id, bytes_off);
+			} else {
+#ifdef CONFIG_SSDFS_DEBUG
+				SSDFS_DBG("partial log header is corrupted: "
+					  "peb_id %llu, bytes_off %u\n",
+					  peb_id, bytes_off);
+#endif /* CONFIG_SSDFS_DEBUG */
+			}
+
+			return err;
+		}
+	} else {
+		if (!silent) {
+			SSDFS_ERR("log footer is corrupted: "
+				  "peb_id %llu, bytes_off %u\n",
+				  peb_id, bytes_off);
+		} else {
+#ifdef CONFIG_SSDFS_DEBUG
+			SSDFS_DBG("log footer is corrupted: "
+				  "peb_id %llu, bytes_off %u\n",
+				  peb_id, bytes_off);
+#endif /* CONFIG_SSDFS_DEBUG */
+		}
+
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/*
+ * ssdfs_store_nsegs() - store volume's segments number in volume state
+ * @fsi: pointer on shared file system object
+ * @vs: volume state [out]
+ *
+ * This function stores volume's segments number in volume state.
+ *
+ * RETURN:
+ * [success]
+ * [failure] - error code:
+ *
+ * %-ENOLCK     - volume is under resize.
+ */
+static inline
+int ssdfs_store_nsegs(struct ssdfs_fs_info *fsi,
+			struct ssdfs_volume_state *vs)
+{
+	mutex_lock(&fsi->resize_mutex);
+	vs->nsegs = cpu_to_le64(fsi->nsegs);
+	mutex_unlock(&fsi->resize_mutex);
+
+	return 0;
+}
+
+/*
+ * ssdfs_prepare_current_segment_ids() - prepare current segment IDs
+ * @fsi: pointer on shared file system object
+ * @array: pointer on array of IDs [out]
+ * @size: size the array in bytes
+ *
+ * This function prepares the current segment IDs.
+ *
+ * RETURN:
+ * [success]
+ * [failure] - error code.
+ */
+int ssdfs_prepare_current_segment_ids(struct ssdfs_fs_info *fsi,
+					__le64 *array,
+					size_t size)
+{
+	size_t count = size / sizeof(__le64);
+	int i;
+
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(!fsi || !array);
+
+	SSDFS_DBG("fsi %p, array %p, size %zu\n",
+		  fsi, array, size);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	if (size != (sizeof(__le64) * SSDFS_CUR_SEGS_COUNT)) {
+		SSDFS_ERR("invalid array size %zu\n",
+			  size);
+		return -EINVAL;
+	}
+
+	memset(array, 0xFF, size);
+
+	if (fsi->cur_segs) {
+		down_read(&fsi->cur_segs->lock);
+		for (i = 0; i < count; i++) {
+			struct ssdfs_segment_info *real_seg;
+			u64 seg;
+
+			if (!fsi->cur_segs->objects[i])
+				continue;
+
+			ssdfs_current_segment_lock(fsi->cur_segs->objects[i]);
+
+			real_seg = fsi->cur_segs->objects[i]->real_seg;
+			if (real_seg) {
+				seg = real_seg->seg_id;
+#ifdef CONFIG_SSDFS_DEBUG
+				SSDFS_DBG("index %d, seg_id %llu\n",
+					  i, seg);
+#endif /* CONFIG_SSDFS_DEBUG */
+				array[i] = cpu_to_le64(seg);
+			} else {
+				seg = fsi->cur_segs->objects[i]->seg_id;
+#ifdef CONFIG_SSDFS_DEBUG
+				SSDFS_DBG("index %d, seg_id %llu\n",
+					  i, seg);
+#endif /* CONFIG_SSDFS_DEBUG */
+				array[i] = cpu_to_le64(seg);
+			}
+
+			ssdfs_current_segment_unlock(fsi->cur_segs->objects[i]);
+		}
+		up_read(&fsi->cur_segs->lock);
+	}
+
+	return 0;
+}
+
+/*
+ * ssdfs_prepare_volume_state_info_for_commit() - prepare volume state
+ * @fsi: pointer on shared file system object
+ * @fs_state: file system state
+ * @array: pointer on array of IDs
+ * @size: size the array in bytes
+ * @last_log_time: log creation timestamp
+ * @last_log_cno: last log checkpoint
+ * @vs: volume state [out]
+ *
+ * This function prepares volume state info for commit.
+ *
+ * RETURN:
+ * [success]
+ * [failure] - error code.
+ */
+int ssdfs_prepare_volume_state_info_for_commit(struct ssdfs_fs_info *fsi,
+						u16 fs_state,
+						__le64 *cur_segs,
+						size_t size,
+						u64 last_log_time,
+						u64 last_log_cno,
+						struct ssdfs_volume_state *vs)
+{
+	int err;
+
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(!fsi || !vs);
+
+	SSDFS_DBG("fsi %p, fs_state %#x\n", fsi, fs_state);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	if (size != (sizeof(__le64) * SSDFS_CUR_SEGS_COUNT)) {
+		SSDFS_ERR("invalid array size %zu\n",
+			  size);
+		return -EINVAL;
+	}
+
+	err = ssdfs_store_nsegs(fsi, vs);
+	if (err) {
+		SSDFS_DBG("unable to store segments number: err %d\n", err);
+		return err;
+	}
+
+	vs->magic.common = cpu_to_le32(SSDFS_SUPER_MAGIC);
+	vs->magic.version.major = SSDFS_MAJOR_REVISION;
+	vs->magic.version.minor = SSDFS_MINOR_REVISION;
+
+	spin_lock(&fsi->volume_state_lock);
+
+	fsi->fs_mod_time = last_log_time;
+	fsi->fs_state = fs_state;
+
+	vs->free_pages = cpu_to_le64(fsi->free_pages);
+	vs->timestamp = cpu_to_le64(last_log_time);
+	vs->cno = cpu_to_le64(last_log_cno);
+	vs->flags = cpu_to_le32(fsi->fs_flags);
+	vs->state = cpu_to_le16(fs_state);
+	vs->errors = cpu_to_le16(fsi->fs_errors);
+	vs->feature_compat = cpu_to_le64(fsi->fs_feature_compat);
+	vs->feature_compat_ro = cpu_to_le64(fsi->fs_feature_compat_ro);
+	vs->feature_incompat = cpu_to_le64(fsi->fs_feature_incompat);
+
+	ssdfs_memcpy(vs->uuid, 0, SSDFS_UUID_SIZE,
+		     fsi->vs->uuid, 0, SSDFS_UUID_SIZE,
+		     SSDFS_UUID_SIZE);
+	ssdfs_memcpy(vs->label, 0, SSDFS_VOLUME_LABEL_MAX,
+		     fsi->vs->label, 0, SSDFS_VOLUME_LABEL_MAX,
+		     SSDFS_VOLUME_LABEL_MAX);
+	ssdfs_memcpy(vs->cur_segs, 0, size,
+		     cur_segs, 0, size,
+		     size);
+
+	vs->migration_threshold = cpu_to_le16(fsi->migration_threshold);
+	vs->open_zones = cpu_to_le32(atomic_read(&fsi->open_zones));
+
+	spin_unlock(&fsi->volume_state_lock);
+
+#ifdef CONFIG_SSDFS_DEBUG
+	SSDFS_DBG("open_zones %d\n",
+		  atomic_read(&fsi->open_zones));
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	ssdfs_memcpy(&vs->blkbmap,
+		     0, sizeof(struct ssdfs_blk_bmap_options),
+		     &fsi->vs->blkbmap,
+		     0, sizeof(struct ssdfs_blk_bmap_options),
+		     sizeof(struct ssdfs_blk_bmap_options));
+	ssdfs_memcpy(&vs->blk2off_tbl,
+		     0, sizeof(struct ssdfs_blk2off_tbl_options),
+		     &fsi->vs->blk2off_tbl,
+		     0, sizeof(struct ssdfs_blk2off_tbl_options),
+		     sizeof(struct ssdfs_blk2off_tbl_options));
+
+	ssdfs_memcpy(&vs->user_data,
+		     0, sizeof(struct ssdfs_user_data_options),
+		     &fsi->vs->user_data,
+		     0, sizeof(struct ssdfs_user_data_options),
+		     sizeof(struct ssdfs_user_data_options));
+	ssdfs_memcpy(&vs->root_folder,
+		     0, sizeof(struct ssdfs_inode),
+		     &fsi->vs->root_folder,
+		     0, sizeof(struct ssdfs_inode),
+		     sizeof(struct ssdfs_inode));
+
+	ssdfs_memcpy(&vs->inodes_btree,
+		     0, sizeof(struct ssdfs_inodes_btree),
+		     &fsi->vs->inodes_btree,
+		     0, sizeof(struct ssdfs_inodes_btree),
+		     sizeof(struct ssdfs_inodes_btree));
+	ssdfs_memcpy(&vs->shared_extents_btree,
+		     0, sizeof(struct ssdfs_shared_extents_btree),
+		     &fsi->vs->shared_extents_btree,
+		     0, sizeof(struct ssdfs_shared_extents_btree),
+		     sizeof(struct ssdfs_shared_extents_btree));
+	ssdfs_memcpy(&vs->shared_dict_btree,
+		     0, sizeof(struct ssdfs_shared_dictionary_btree),
+		     &fsi->vs->shared_dict_btree,
+		     0, sizeof(struct ssdfs_shared_dictionary_btree),
+		     sizeof(struct ssdfs_shared_dictionary_btree));
+	ssdfs_memcpy(&vs->snapshots_btree,
+		     0, sizeof(struct ssdfs_snapshots_btree),
+		     &fsi->vs->snapshots_btree,
+		     0, sizeof(struct ssdfs_snapshots_btree),
+		     sizeof(struct ssdfs_snapshots_btree));
+
+	return 0;
+}
+
+/*
+ * ssdfs_prepare_log_footer_for_commit() - prepare log footer for commit
+ * @fsi: pointer on shared file system object
+ * @log_pages: count of pages in the log
+ * @log_flags: log's flags
+ * @last_log_time: log creation timestamp
+ * @last_log_cno: last log checkpoint
+ * @footer: log footer [out]
+ *
+ * This function prepares log footer for commit.
+ *
+ * RETURN:
+ * [success]
+ * [failure] - error code:
+ *
+ * %-EINVAL     - invalid input values.
+ */
+int ssdfs_prepare_log_footer_for_commit(struct ssdfs_fs_info *fsi,
+					u32 log_pages,
+					u32 log_flags,
+					u64 last_log_time,
+					u64 last_log_cno,
+					struct ssdfs_log_footer *footer)
+{
+	u16 data_size = sizeof(struct ssdfs_log_footer);
+	int err;
+
+#ifdef CONFIG_SSDFS_DEBUG
+	SSDFS_DBG("fsi %p, log_pages %u, log_flags %#x, footer %p\n",
+		  fsi, log_pages, log_flags, footer);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	footer->volume_state.magic.key = cpu_to_le16(SSDFS_LOG_FOOTER_MAGIC);
+
+	footer->timestamp = cpu_to_le64(last_log_time);
+	footer->cno = cpu_to_le64(last_log_cno);
+
+	if (log_pages >= (U32_MAX >> fsi->log_pagesize)) {
+		SSDFS_ERR("invalid value of log_pages %u\n", log_pages);
+		return -EINVAL;
+	}
+
+	footer->log_bytes = cpu_to_le32(log_pages << fsi->log_pagesize);
+
+	if (log_flags & ~SSDFS_LOG_FOOTER_FLAG_MASK) {
+		SSDFS_ERR("unknow log flags %#x\n", log_flags);
+		return -EINVAL;
+	}
+
+	footer->log_flags = cpu_to_le32(log_flags);
+
+	footer->volume_state.check.bytes = cpu_to_le16(data_size);
+	footer->volume_state.check.flags = cpu_to_le16(SSDFS_CRC32);
+
+	err = ssdfs_calculate_csum(&footer->volume_state.check,
+				   footer, data_size);
+	if (unlikely(err)) {
+		SSDFS_ERR("unable to calculate checksum: err %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
diff --git a/fs/ssdfs/volume_header.c b/fs/ssdfs/volume_header.c
new file mode 100644
index 000000000000..e992c3cdf335
--- /dev/null
+++ b/fs/ssdfs/volume_header.c
@@ -0,0 +1,1256 @@
+// SPDX-License-Identifier: BSD-3-Clause-Clear
+/*
+ * SSDFS -- SSD-oriented File System.
+ *
+ * fs/ssdfs/volume_header.c - operations with volume header.
+ *
+ * Copyright (c) 2014-2019 HGST, a Western Digital Company.
+ *              http://www.hgst.com/
+ * Copyright (c) 2014-2023 Viacheslav Dubeyko <slava@dubeyko.com>
+ *              http://www.ssdfs.org/
+ *
+ * (C) Copyright 2014-2019, HGST, Inc., All rights reserved.
+ *
+ * Created by HGST, San Jose Research Center, Storage Architecture Group
+ *
+ * Authors: Viacheslav Dubeyko <slava@dubeyko.com>
+ *
+ * Acknowledgement: Cyril Guyot
+ *                  Zvonimir Bandic
+ */
+
+#include <linux/kernel.h>
+#include <linux/rwsem.h>
+#include <linux/pagevec.h>
+
+#include "peb_mapping_queue.h"
+#include "peb_mapping_table_cache.h"
+#include "ssdfs.h"
+
+#include <trace/events/ssdfs.h>
+
+/*
+ * __is_ssdfs_segment_header_magic_valid() - check segment header's magic
+ * @magic: pointer on magic value
+ */
+bool __is_ssdfs_segment_header_magic_valid(struct ssdfs_signature *magic)
+{
+	return le16_to_cpu(magic->key) == SSDFS_SEGMENT_HDR_MAGIC;
+}
+
+/*
+ * is_ssdfs_segment_header_magic_valid() - check segment header's magic
+ * @hdr: segment header
+ */
+bool is_ssdfs_segment_header_magic_valid(struct ssdfs_segment_header *hdr)
+{
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(!hdr);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	return __is_ssdfs_segment_header_magic_valid(&hdr->volume_hdr.magic);
+}
+
+/*
+ * is_ssdfs_partial_log_header_magic_valid() - check partial log header's magic
+ * @magic: pointer on magic value
+ */
+bool is_ssdfs_partial_log_header_magic_valid(struct ssdfs_signature *magic)
+{
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(!magic);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	return le16_to_cpu(magic->key) == SSDFS_PARTIAL_LOG_HDR_MAGIC;
+}
+
+/*
+ * is_ssdfs_volume_header_csum_valid() - check volume header checksum
+ * @vh_buf: volume header buffer
+ * @buf_size: size of buffer in bytes
+ */
+bool is_ssdfs_volume_header_csum_valid(void *vh_buf, size_t buf_size)
+{
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(!vh_buf);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	return is_csum_valid(&SSDFS_VH(vh_buf)->check, vh_buf, buf_size);
+}
+
+/*
+ * is_ssdfs_partial_log_header_csum_valid() - check partial log header checksum
+ * @plh_buf: partial log header buffer
+ * @buf_size: size of buffer in bytes
+ */
+bool is_ssdfs_partial_log_header_csum_valid(void *plh_buf, size_t buf_size)
+{
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(!plh_buf);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	return is_csum_valid(&SSDFS_PLH(plh_buf)->check, plh_buf, buf_size);
+}
+
+static inline
+void ssdfs_show_volume_header(struct ssdfs_volume_header *hdr)
+{
+	SSDFS_ERR("MAGIC: common %#x, key %#x, "
+		  "version (major %u, minor %u)\n",
+		  le32_to_cpu(hdr->magic.common),
+		  le16_to_cpu(hdr->magic.key),
+		  hdr->magic.version.major,
+		  hdr->magic.version.minor);
+	SSDFS_ERR("CHECK: bytes %u, flags %#x, csum %#x\n",
+		  le16_to_cpu(hdr->check.bytes),
+		  le16_to_cpu(hdr->check.flags),
+		  le32_to_cpu(hdr->check.csum));
+	SSDFS_ERR("KEY VALUES: log_pagesize %u, log_erasesize %u, "
+		  "log_segsize %u, log_pebs_per_seg %u, "
+		  "megabytes_per_peb %u, pebs_per_seg %u, "
+		  "create_time %llu, create_cno %llu, flags %#x\n",
+		  hdr->log_pagesize,
+		  hdr->log_erasesize,
+		  hdr->log_segsize,
+		  hdr->log_pebs_per_seg,
+		  le16_to_cpu(hdr->megabytes_per_peb),
+		  le16_to_cpu(hdr->pebs_per_seg),
+		  le64_to_cpu(hdr->create_time),
+		  le64_to_cpu(hdr->create_cno),
+		  le32_to_cpu(hdr->flags));
+}
+
+/*
+ * is_ssdfs_volume_header_consistent() - check volume header consistency
+ * @fsi: pointer on shared file system object
+ * @vh: volume header
+ * @dev_size: partition size in bytes
+ *
+ * RETURN:
+ * [true]  - volume header is consistent.
+ * [false] - volume header is corrupted.
+ */
+bool is_ssdfs_volume_header_consistent(struct ssdfs_fs_info *fsi,
+					struct ssdfs_volume_header *vh,
+					u64 dev_size)
+{
+	u32 page_size;
+	u64 erase_size;
+	u32 seg_size;
+	u32 pebs_per_seg;
+	u64 leb_array[SSDFS_SB_CHAIN_MAX * SSDFS_SB_SEG_COPY_MAX] = {0};
+	u64 peb_array[SSDFS_SB_CHAIN_MAX * SSDFS_SB_SEG_COPY_MAX] = {0};
+	int array_index = 0;
+	int i, j, k;
+
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(!vh);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	page_size = 1 << vh->log_pagesize;
+	erase_size = 1 << vh->log_erasesize;
+	seg_size = 1 << vh->log_segsize;
+	pebs_per_seg = 1 << vh->log_pebs_per_seg;
+
+	if (page_size >= erase_size) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("page_size %u >= erase_size %llu\n",
+			  page_size, erase_size);
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	switch (page_size) {
+	case SSDFS_4KB:
+	case SSDFS_8KB:
+	case SSDFS_16KB:
+	case SSDFS_32KB:
+		/* do nothing */
+		break;
+
+	default:
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("unexpected page_size %u\n", page_size);
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	switch (erase_size) {
+	case SSDFS_128KB:
+	case SSDFS_256KB:
+	case SSDFS_512KB:
+	case SSDFS_2MB:
+	case SSDFS_8MB:
+	case SSDFS_16MB:
+	case SSDFS_32MB:
+	case SSDFS_64MB:
+	case SSDFS_128MB:
+	case SSDFS_256MB:
+	case SSDFS_512MB:
+	case SSDFS_1GB:
+	case SSDFS_2GB:
+	case SSDFS_8GB:
+	case SSDFS_16GB:
+	case SSDFS_32GB:
+	case SSDFS_64GB:
+		/* do nothing */
+		break;
+
+	default:
+		if (fsi->is_zns_device) {
+			u64 zone_size = le16_to_cpu(vh->megabytes_per_peb);
+
+			zone_size *= SSDFS_1MB;
+
+			if (fsi->zone_size != zone_size) {
+				SSDFS_ERR("invalid zone size: "
+					  "size1 %llu != size2 %llu\n",
+					  fsi->zone_size, zone_size);
+				return -ERANGE;
+			}
+
+			erase_size = zone_size;
+		} else {
+#ifdef CONFIG_SSDFS_DEBUG
+			SSDFS_DBG("unexpected erase_size %llu\n", erase_size);
+#endif /* CONFIG_SSDFS_DEBUG */
+			return false;
+		}
+	};
+
+	if (seg_size < erase_size) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("seg_size %u < erase_size %llu\n",
+			  seg_size, erase_size);
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	if (pebs_per_seg != (seg_size >> vh->log_erasesize)) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("pebs_per_seg %u != (seg_size %u / erase_size %llu)\n",
+			  pebs_per_seg, seg_size, erase_size);
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	if (seg_size >= dev_size) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("seg_size %u >= dev_size %llu\n",
+			  seg_size, dev_size);
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	for (i = 0; i < SSDFS_SB_CHAIN_MAX; i++) {
+		for (j = 0; j < SSDFS_SB_SEG_COPY_MAX; j++) {
+			u64 leb_id = le64_to_cpu(vh->sb_pebs[i][j].leb_id);
+			u64 peb_id = le64_to_cpu(vh->sb_pebs[i][j].peb_id);
+
+#ifdef CONFIG_SSDFS_DEBUG
+			SSDFS_DBG("i %d, j %d, LEB %llu, PEB %llu\n",
+				  i, j, leb_id, peb_id);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+			for (k = 0; k < array_index; k++) {
+				if (leb_id == leb_array[k]) {
+#ifdef CONFIG_SSDFS_DEBUG
+					SSDFS_DBG("corrupted LEB number: "
+						  "leb_id %llu, "
+						  "leb_array[%d] %llu\n",
+						  leb_id, k,
+						  leb_array[k]);
+#endif /* CONFIG_SSDFS_DEBUG */
+					return false;
+				}
+
+				if (peb_id == peb_array[k]) {
+#ifdef CONFIG_SSDFS_DEBUG
+					SSDFS_DBG("corrupted PEB number: "
+						  "peb_id %llu, "
+						  "peb_array[%d] %llu\n",
+						  peb_id, k,
+						  peb_array[k]);
+#endif /* CONFIG_SSDFS_DEBUG */
+					return false;
+				}
+			}
+
+			if (i == SSDFS_PREV_SB_SEG &&
+			    leb_id == U64_MAX && peb_id == U64_MAX) {
+				/* prev id is U64_MAX after volume creation */
+				continue;
+			}
+
+			if (i == SSDFS_RESERVED_SB_SEG &&
+			    leb_id == U64_MAX && peb_id == U64_MAX) {
+				/*
+				 * The reserved seg could be U64_MAX
+				 * if there is no clean segment.
+				 */
+				continue;
+			}
+
+			if (leb_id >= (dev_size >> vh->log_erasesize)) {
+#ifdef CONFIG_SSDFS_DEBUG
+				SSDFS_DBG("corrupted LEB number %llu\n",
+					  leb_id);
+#endif /* CONFIG_SSDFS_DEBUG */
+				return false;
+			}
+
+			leb_array[array_index] = leb_id;
+			peb_array[array_index] = peb_id;
+
+			array_index++;
+		}
+	}
+
+	return true;
+}
+
+/*
+ * ssdfs_check_segment_header() - check segment header consistency
+ * @fsi: pointer on shared file system object
+ * @hdr: segment header
+ * @silent: show error or not?
+ *
+ * This function checks consistency of segment header.
+ *
+ * RETURN:
+ * [success] - segment header is consistent.
+ * [failure] - error code:
+ *
+ * %-ENODATA     - valid magic doesn't detected.
+ * %-EIO         - segment header is corrupted.
+ */
+int ssdfs_check_segment_header(struct ssdfs_fs_info *fsi,
+				struct ssdfs_segment_header *hdr,
+				bool silent)
+{
+	struct ssdfs_volume_header *vh;
+	size_t hdr_size = sizeof(struct ssdfs_segment_header);
+	bool major_magic_valid, minor_magic_valid;
+	u64 dev_size;
+
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(!fsi || !hdr);
+
+	SSDFS_DBG("fsi %p, hdr %p, silent %#x\n", fsi, hdr, silent);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	vh = SSDFS_VH(hdr);
+
+	major_magic_valid = is_ssdfs_magic_valid(&vh->magic);
+	minor_magic_valid = is_ssdfs_segment_header_magic_valid(hdr);
+
+	if (!major_magic_valid && !minor_magic_valid) {
+		if (!silent) {
+			SSDFS_ERR("valid magic doesn't detected\n");
+			ssdfs_show_volume_header(vh);
+		} else
+			SSDFS_DBG("valid magic doesn't detected\n");
+		return -ENODATA;
+	} else if (!major_magic_valid) {
+		if (!silent) {
+			SSDFS_ERR("invalid SSDFS magic signature\n");
+			ssdfs_show_volume_header(vh);
+		} else
+			SSDFS_DBG("invalid SSDFS magic signature\n");
+		return -EIO;
+	} else if (!minor_magic_valid) {
+		if (!silent) {
+			SSDFS_ERR("invalid segment header magic signature\n");
+			ssdfs_show_volume_header(vh);
+		} else
+			SSDFS_DBG("invalid segment header magic signature\n");
+		return -EIO;
+	}
+
+	if (!is_ssdfs_volume_header_csum_valid(hdr, hdr_size)) {
+		if (!silent) {
+			SSDFS_ERR("invalid checksum of volume header\n");
+			ssdfs_show_volume_header(vh);
+		} else
+			SSDFS_DBG("invalid checksum of volume header\n");
+		return -EIO;
+	}
+
+	dev_size = fsi->devops->device_size(fsi->sb);
+	if (!is_ssdfs_volume_header_consistent(fsi, vh, dev_size)) {
+		if (!silent) {
+			SSDFS_ERR("volume header is corrupted\n");
+			ssdfs_show_volume_header(vh);
+		} else
+			SSDFS_DBG("volume header is corrupted\n");
+		return -EIO;
+	}
+
+	if (SSDFS_VH_CNO(vh) > SSDFS_SEG_CNO(hdr)) {
+		if (!silent) {
+			SSDFS_ERR("invalid checkpoint/timestamp\n");
+			ssdfs_show_volume_header(vh);
+		} else
+			SSDFS_DBG("invalid checkpoint/timestamp\n");
+		return -EIO;
+	}
+
+	if (le16_to_cpu(hdr->log_pages) > fsi->pages_per_peb) {
+		if (!silent) {
+			SSDFS_ERR("log_pages %u > pages_per_peb %u\n",
+				  le16_to_cpu(hdr->log_pages),
+				  fsi->pages_per_peb);
+			ssdfs_show_volume_header(vh);
+		} else {
+#ifdef CONFIG_SSDFS_DEBUG
+			SSDFS_DBG("log_pages %u > pages_per_peb %u\n",
+				  le16_to_cpu(hdr->log_pages),
+				  fsi->pages_per_peb);
+#endif /* CONFIG_SSDFS_DEBUG */
+		}
+		return -EIO;
+	}
+
+	if (le16_to_cpu(hdr->seg_type) > SSDFS_LAST_KNOWN_SEG_TYPE) {
+		if (!silent) {
+			SSDFS_ERR("unknown seg_type %#x\n",
+				  le16_to_cpu(hdr->seg_type));
+			ssdfs_show_volume_header(vh);
+		} else {
+#ifdef CONFIG_SSDFS_DEBUG
+			SSDFS_DBG("unknown seg_type %#x\n",
+				  le16_to_cpu(hdr->seg_type));
+#endif /* CONFIG_SSDFS_DEBUG */
+		}
+		return -EIO;
+	}
+
+	if (le32_to_cpu(hdr->seg_flags) & ~SSDFS_SEG_HDR_FLAG_MASK) {
+		if (!silent) {
+			SSDFS_ERR("corrupted seg_flags %#x\n",
+				  le32_to_cpu(hdr->seg_flags));
+			ssdfs_show_volume_header(vh);
+		} else {
+#ifdef CONFIG_SSDFS_DEBUG
+			SSDFS_DBG("corrupted seg_flags %#x\n",
+				  le32_to_cpu(hdr->seg_flags));
+#endif /* CONFIG_SSDFS_DEBUG */
+		}
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/*
+ * is_ssdfs_partial_log_header_consistent() - check partial header consistency
+ * @fsi: pointer on shared file system object
+ * @ph: partial log header
+ * @dev_size: partition size in bytes
+ *
+ * RETURN:
+ * [true]  - partial log header is consistent.
+ * [false] - partial log header is corrupted.
+ */
+bool is_ssdfs_partial_log_header_consistent(struct ssdfs_fs_info *fsi,
+					    struct ssdfs_partial_log_header *ph,
+					    u64 dev_size)
+{
+	u32 page_size;
+	u64 erase_size;
+	u32 seg_size;
+	u32 pebs_per_seg;
+	u64 nsegs;
+	u64 free_pages;
+	u64 pages_count;
+	u32 remainder;
+	u32 pages_per_seg;
+
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(!ph);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	page_size = 1 << ph->log_pagesize;
+	erase_size = 1 << ph->log_erasesize;
+	seg_size = 1 << ph->log_segsize;
+	pebs_per_seg = 1 << ph->log_pebs_per_seg;
+
+	if (page_size >= erase_size) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("page_size %u >= erase_size %llu\n",
+			  page_size, erase_size);
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	switch (page_size) {
+	case SSDFS_4KB:
+	case SSDFS_8KB:
+	case SSDFS_16KB:
+	case SSDFS_32KB:
+		/* do nothing */
+		break;
+
+	default:
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("unexpected page_size %u\n", page_size);
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	switch (erase_size) {
+	case SSDFS_128KB:
+	case SSDFS_256KB:
+	case SSDFS_512KB:
+	case SSDFS_2MB:
+	case SSDFS_8MB:
+	case SSDFS_16MB:
+	case SSDFS_32MB:
+	case SSDFS_64MB:
+	case SSDFS_128MB:
+	case SSDFS_256MB:
+	case SSDFS_512MB:
+	case SSDFS_1GB:
+	case SSDFS_2GB:
+	case SSDFS_8GB:
+	case SSDFS_16GB:
+	case SSDFS_32GB:
+	case SSDFS_64GB:
+		/* do nothing */
+		break;
+
+	default:
+		if (fsi->is_zns_device) {
+			u64 zone_size = le16_to_cpu(fsi->vh->megabytes_per_peb);
+
+			zone_size *= SSDFS_1MB;
+
+			if (fsi->zone_size != zone_size) {
+				SSDFS_ERR("invalid zone size: "
+					  "size1 %llu != size2 %llu\n",
+					  fsi->zone_size, zone_size);
+				return -ERANGE;
+			}
+
+			erase_size = (u32)zone_size;
+		} else {
+#ifdef CONFIG_SSDFS_DEBUG
+			SSDFS_DBG("unexpected erase_size %llu\n", erase_size);
+#endif /* CONFIG_SSDFS_DEBUG */
+			return false;
+		}
+	};
+
+	if (seg_size < erase_size) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("seg_size %u < erase_size %llu\n",
+			  seg_size, erase_size);
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	if (pebs_per_seg != (seg_size >> ph->log_erasesize)) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("pebs_per_seg %u != (seg_size %u / erase_size %llu)\n",
+			  pebs_per_seg, seg_size, erase_size);
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	if (seg_size >= dev_size) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("seg_size %u >= dev_size %llu\n",
+			  seg_size, dev_size);
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	nsegs = le64_to_cpu(ph->nsegs);
+
+	if (nsegs == 0 || nsegs > (dev_size >> ph->log_segsize)) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("invalid nsegs %llu, dev_size %llu, seg_size) %u\n",
+			  nsegs, dev_size, seg_size);
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	free_pages = le64_to_cpu(ph->free_pages);
+
+	pages_count = div_u64_rem(dev_size, page_size, &remainder);
+	if (remainder) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("dev_size %llu is unaligned on page_size %u\n",
+			  dev_size, page_size);
+#endif /* CONFIG_SSDFS_DEBUG */
+	}
+
+	if (free_pages > pages_count) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("free_pages %llu is greater than pages_count %llu\n",
+			  free_pages, pages_count);
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	pages_per_seg = seg_size / page_size;
+	if (nsegs <= div_u64(free_pages, pages_per_seg)) {
+#ifdef CONFIG_SSDFS_DEBUG
+		SSDFS_DBG("invalid nsegs %llu, free_pages %llu, "
+			  "pages_per_seg %u\n",
+			  nsegs, free_pages, pages_per_seg);
+#endif /* CONFIG_SSDFS_DEBUG */
+		return false;
+	}
+
+	return true;
+}
+
+/*
+ * ssdfs_check_partial_log_header() - check partial log header consistency
+ * @fsi: pointer on shared file system object
+ * @hdr: partial log header
+ * @silent: show error or not?
+ *
+ * This function checks consistency of partial log header.
+ *
+ * RETURN:
+ * [success] - partial log header is consistent.
+ * [failure] - error code:
+ *
+ * %-ENODATA     - valid magic doesn't detected.
+ * %-EIO         - partial log header is corrupted.
+ */
+int ssdfs_check_partial_log_header(struct ssdfs_fs_info *fsi,
+				   struct ssdfs_partial_log_header *hdr,
+				   bool silent)
+{
+	size_t hdr_size = sizeof(struct ssdfs_partial_log_header);
+	bool major_magic_valid, minor_magic_valid;
+	u64 dev_size;
+	u32 log_bytes;
+
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(!fsi || !hdr);
+
+	SSDFS_DBG("fsi %p, hdr %p, silent %#x\n", fsi, hdr, silent);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	major_magic_valid = is_ssdfs_magic_valid(&hdr->magic);
+	minor_magic_valid =
+		is_ssdfs_partial_log_header_magic_valid(&hdr->magic);
+
+	if (!major_magic_valid && !minor_magic_valid) {
+		if (!silent)
+			SSDFS_ERR("valid magic doesn't detected\n");
+		else
+			SSDFS_DBG("valid magic doesn't detected\n");
+		return -ENODATA;
+	} else if (!major_magic_valid) {
+		if (!silent)
+			SSDFS_ERR("invalid SSDFS magic signature\n");
+		else
+			SSDFS_DBG("invalid SSDFS magic signature\n");
+		return -EIO;
+	} else if (!minor_magic_valid) {
+		if (!silent)
+			SSDFS_ERR("invalid partial log header magic\n");
+		else
+			SSDFS_DBG("invalid partial log header magic\n");
+		return -EIO;
+	}
+
+	if (!is_ssdfs_partial_log_header_csum_valid(hdr, hdr_size)) {
+		if (!silent)
+			SSDFS_ERR("invalid checksum of partial log header\n");
+		else
+			SSDFS_DBG("invalid checksum of partial log header\n");
+		return -EIO;
+	}
+
+	dev_size = fsi->devops->device_size(fsi->sb);
+	if (!is_ssdfs_partial_log_header_consistent(fsi, hdr, dev_size)) {
+		if (!silent)
+			SSDFS_ERR("partial log header is corrupted\n");
+		else
+			SSDFS_DBG("partial log header is corrupted\n");
+		return -EIO;
+	}
+
+	if (le16_to_cpu(hdr->log_pages) > fsi->pages_per_peb) {
+		if (!silent) {
+			SSDFS_ERR("log_pages %u > pages_per_peb %u\n",
+				  le16_to_cpu(hdr->log_pages),
+				  fsi->pages_per_peb);
+		} else {
+#ifdef CONFIG_SSDFS_DEBUG
+			SSDFS_DBG("log_pages %u > pages_per_peb %u\n",
+				  le16_to_cpu(hdr->log_pages),
+				  fsi->pages_per_peb);
+#endif /* CONFIG_SSDFS_DEBUG */
+		}
+		return -EIO;
+	}
+
+	log_bytes = (u32)le16_to_cpu(hdr->log_pages) * fsi->pagesize;
+	if (le32_to_cpu(hdr->log_bytes) > log_bytes) {
+		if (!silent) {
+			SSDFS_ERR("calculated log_bytes %u < log_bytes %u\n",
+				  log_bytes,
+				  le32_to_cpu(hdr->log_bytes));
+		} else {
+#ifdef CONFIG_SSDFS_DEBUG
+			SSDFS_DBG("calculated log_bytes %u < log_bytes %u\n",
+				  log_bytes,
+				  le32_to_cpu(hdr->log_bytes));
+#endif /* CONFIG_SSDFS_DEBUG */
+		}
+		return -EIO;
+	}
+
+	if (le16_to_cpu(hdr->seg_type) > SSDFS_LAST_KNOWN_SEG_TYPE) {
+		if (!silent) {
+			SSDFS_ERR("unknown seg_type %#x\n",
+				  le16_to_cpu(hdr->seg_type));
+		} else {
+#ifdef CONFIG_SSDFS_DEBUG
+			SSDFS_DBG("unknown seg_type %#x\n",
+				  le16_to_cpu(hdr->seg_type));
+#endif /* CONFIG_SSDFS_DEBUG */
+		}
+		return -EIO;
+	}
+
+	if (le32_to_cpu(hdr->pl_flags) & ~SSDFS_SEG_HDR_FLAG_MASK) {
+		if (!silent) {
+			SSDFS_ERR("corrupted pl_flags %#x\n",
+				  le32_to_cpu(hdr->pl_flags));
+		} else {
+#ifdef CONFIG_SSDFS_DEBUG
+			SSDFS_DBG("corrupted pl_flags %#x\n",
+				  le32_to_cpu(hdr->pl_flags));
+#endif /* CONFIG_SSDFS_DEBUG */
+		}
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/*
+ * ssdfs_read_checked_segment_header() - read and check segment header
+ * @fsi: pointer on shared file system object
+ * @peb_id: PEB identification number
+ * @pages_off: offset from PEB's begin in pages
+ * @buf: buffer
+ * @silent: show error or not?
+ *
+ * This function reads and checks consistency of segment header.
+ *
+ * RETURN:
+ * [success] - segment header is consistent.
+ * [failure] - error code:
+ *
+ * %-ENODATA     - valid magic doesn't detected.
+ * %-EIO         - segment header is corrupted.
+ */
+int ssdfs_read_checked_segment_header(struct ssdfs_fs_info *fsi,
+					u64 peb_id, u32 pages_off,
+					void *buf, bool silent)
+{
+	struct ssdfs_signature *magic;
+	struct ssdfs_segment_header *hdr;
+	struct ssdfs_partial_log_header *pl_hdr;
+	size_t hdr_size = sizeof(struct ssdfs_segment_header);
+	u64 offset = 0;
+	size_t read_bytes;
+	int err;
+
+#ifdef CONFIG_SSDFS_DEBUG
+	SSDFS_DBG("peb_id %llu, pages_off %u, buf %p, silent %#x\n",
+		  peb_id, pages_off, buf, silent);
+
+	BUG_ON(!fsi);
+	BUG_ON(!fsi->devops->read);
+	BUG_ON(!buf);
+	BUG_ON(pages_off >= fsi->pages_per_peb);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	if (peb_id == 0 && pages_off == 0)
+		offset = SSDFS_RESERVED_VBR_SIZE;
+	else
+		offset = (u64)pages_off * fsi->pagesize;
+
+	err = ssdfs_aligned_read_buffer(fsi, peb_id, offset,
+					buf, hdr_size,
+					&read_bytes);
+	if (unlikely(err)) {
+		if (!silent) {
+			SSDFS_ERR("fail to read segment header: "
+				  "peb_id %llu, pages_off %u, err %d\n",
+				  peb_id, pages_off, err);
+		} else {
+#ifdef CONFIG_SSDFS_DEBUG
+			SSDFS_DBG("fail to read segment header: "
+				  "peb_id %llu, pages_off %u, err %d\n",
+				  peb_id, pages_off, err);
+#endif /* CONFIG_SSDFS_DEBUG */
+		}
+		return err;
+	}
+
+	if (unlikely(read_bytes != hdr_size)) {
+		if (!silent) {
+			SSDFS_ERR("fail to read segment header: "
+				  "peb_id %llu, pages_off %u: "
+				  "read_bytes %zu != hdr_size %zu\n",
+				  peb_id, pages_off, read_bytes, hdr_size);
+		} else {
+#ifdef CONFIG_SSDFS_DEBUG
+			SSDFS_DBG("fail to read segment header: "
+				  "peb_id %llu, pages_off %u: "
+				  "read_bytes %zu != hdr_size %zu\n",
+				  peb_id, pages_off, read_bytes, hdr_size);
+#endif /* CONFIG_SSDFS_DEBUG */
+		}
+		return -ERANGE;
+	}
+
+	magic = (struct ssdfs_signature *)buf;
+
+	if (!is_ssdfs_magic_valid(magic)) {
+		if (!silent)
+			SSDFS_ERR("valid magic is not detected\n");
+		else
+			SSDFS_DBG("valid magic is not detected\n");
+
+		return -ENODATA;
+	}
+
+	if (__is_ssdfs_segment_header_magic_valid(magic)) {
+		hdr = SSDFS_SEG_HDR(buf);
+
+		err = ssdfs_check_segment_header(fsi, hdr, silent);
+		if (unlikely(err)) {
+			if (!silent) {
+				SSDFS_ERR("segment header is corrupted: "
+					  "peb_id %llu, pages_off %u, err %d\n",
+					  peb_id, pages_off, err);
+			} else {
+#ifdef CONFIG_SSDFS_DEBUG
+				SSDFS_DBG("segment header is corrupted: "
+					  "peb_id %llu, pages_off %u, err %d\n",
+					  peb_id, pages_off, err);
+#endif /* CONFIG_SSDFS_DEBUG */
+			}
+
+			return err;
+		}
+	} else if (is_ssdfs_partial_log_header_magic_valid(magic)) {
+		pl_hdr = SSDFS_PLH(buf);
+
+		err = ssdfs_check_partial_log_header(fsi, pl_hdr, silent);
+		if (unlikely(err)) {
+			if (!silent) {
+				SSDFS_ERR("partial log header is corrupted: "
+					  "peb_id %llu, pages_off %u\n",
+					  peb_id, pages_off);
+			} else {
+#ifdef CONFIG_SSDFS_DEBUG
+				SSDFS_DBG("partial log header is corrupted: "
+					  "peb_id %llu, pages_off %u\n",
+					  peb_id, pages_off);
+#endif /* CONFIG_SSDFS_DEBUG */
+			}
+
+			return err;
+		}
+	} else {
+		if (!silent) {
+			SSDFS_ERR("log header is corrupted: "
+				  "peb_id %llu, pages_off %u\n",
+				  peb_id, pages_off);
+		} else {
+#ifdef CONFIG_SSDFS_DEBUG
+			SSDFS_DBG("log header is corrupted: "
+				  "peb_id %llu, pages_off %u\n",
+				  peb_id, pages_off);
+#endif /* CONFIG_SSDFS_DEBUG */
+		}
+
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/*
+ * ssdfs_create_volume_header() - initialize volume header from the scratch
+ * @fsi: pointer on shared file system object
+ * @vh: volume header
+ */
+void ssdfs_create_volume_header(struct ssdfs_fs_info *fsi,
+				struct ssdfs_volume_header *vh)
+{
+	u64 erase_size;
+	u32 megabytes_per_peb;
+	u32 flags;
+
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(!fsi || !vh);
+
+	SSDFS_DBG("fsi %p, vh %p\n", fsi, vh);
+	SSDFS_DBG("fsi->log_pagesize %u, fsi->log_erasesize %u, "
+		  "fsi->log_segsize %u, fsi->log_pebs_per_seg %u\n",
+		  fsi->log_pagesize,
+		  fsi->log_erasesize,
+		  fsi->log_segsize,
+		  fsi->log_pebs_per_seg);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	vh->magic.common = cpu_to_le32(SSDFS_SUPER_MAGIC);
+	vh->magic.key = cpu_to_le16(SSDFS_SEGMENT_HDR_MAGIC);
+	vh->magic.version.major = SSDFS_MAJOR_REVISION;
+	vh->magic.version.minor = SSDFS_MINOR_REVISION;
+
+	vh->log_pagesize = fsi->log_pagesize;
+	vh->log_erasesize = fsi->log_erasesize;
+	vh->log_segsize = fsi->log_segsize;
+	vh->log_pebs_per_seg = fsi->log_pebs_per_seg;
+
+	megabytes_per_peb = fsi->erasesize / SSDFS_1MB;
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(megabytes_per_peb >= U16_MAX);
+#endif /* CONFIG_SSDFS_DEBUG */
+	vh->megabytes_per_peb = cpu_to_le16((u16)megabytes_per_peb);
+
+#ifdef CONFIG_SSDFS_DEBUG
+	BUG_ON(fsi->pebs_per_seg >= U16_MAX);
+#endif /* CONFIG_SSDFS_DEBUG */
+	vh->pebs_per_seg = cpu_to_le16((u16)fsi->pebs_per_seg);
+
+	vh->create_time = cpu_to_le64(fsi->fs_ctime);
+	vh->create_cno = cpu_to_le64(fsi->fs_cno);
+
+	vh->lebs_per_peb_index = cpu_to_le32(fsi->lebs_per_peb_index);
+	vh->create_threads_per_seg = cpu_to_le16(fsi->create_threads_per_seg);
+
+	vh->flags = cpu_to_le32(0);
+
+	if (fsi->is_zns_device) {
+		flags = le32_to_cpu(vh->flags);
+		flags |= SSDFS_VH_ZNS_BASED_VOLUME;
+
+		erase_size = 1 << fsi->log_erasesize;
+		if (erase_size != fsi->zone_size)
+			flags |= SSDFS_VH_UNALIGNED_ZONE;
+
+		vh->flags = cpu_to_le32(flags);
+	}
+
+	vh->sb_seg_log_pages = cpu_to_le16(fsi->sb_seg_log_pages);
+	vh->segbmap_log_pages = cpu_to_le16(fsi->segbmap_log_pages);
+	vh->maptbl_log_pages = cpu_to_le16(fsi->maptbl_log_pages);
+	vh->lnodes_seg_log_pages = cpu_to_le16(fsi->lnodes_seg_log_pages);
+	vh->hnodes_seg_log_pages = cpu_to_le16(fsi->hnodes_seg_log_pages);
+	vh->inodes_seg_log_pages = cpu_to_le16(fsi->inodes_seg_log_pages);
+	vh->user_data_log_pages = cpu_to_le16(fsi->user_data_log_pages);
+
+	ssdfs_memcpy(&vh->segbmap,
+		     0, sizeof(struct ssdfs_segbmap_sb_header),
+		     &fsi->vh->segbmap,
+		     0, sizeof(struct ssdfs_segbmap_sb_header),
+		     sizeof(struct ssdfs_segbmap_sb_header));
+	ssdfs_memcpy(&vh->maptbl,
+		     0, sizeof(struct ssdfs_maptbl_sb_header),
+		     &fsi->vh->maptbl,
+		     0, sizeof(struct ssdfs_maptbl_sb_header),
+		     sizeof(struct ssdfs_maptbl_sb_header));
+	ssdfs_memcpy(&vh->dentries_btree,
+		     0, sizeof(struct ssdfs_dentries_btree_descriptor),
+		     &fsi->vh->dentries_btree,
+		     0, sizeof(struct ssdfs_dentries_btree_descriptor),
+		     sizeof(struct ssdfs_dentries_btree_descriptor));
+	ssdfs_memcpy(&vh->extents_btree,
+		     0, sizeof(struct ssdfs_extents_btree_descriptor),
+		     &fsi->vh->extents_btree,
+		     0, sizeof(struct ssdfs_extents_btree_descriptor),
+		     sizeof(struct ssdfs_extents_btree_descriptor));
+	ssdfs_memcpy(&vh->xattr_btree,
+		     0, sizeof(struct ssdfs_xattr_btree_descriptor),
+		     &fsi->vh->xattr_btree,
+		     0, sizeof(struct ssdfs_xattr_btree_descriptor),
+		     sizeof(struct ssdfs_xattr_btree_descriptor));
+	ssdfs_memcpy(&vh->invextree,
+		     0, sizeof(struct ssdfs_invalidated_extents_btree),
+		     &fsi->vh->invextree,
+		     0, sizeof(struct ssdfs_invalidated_extents_btree),
+		     sizeof(struct ssdfs_invalidated_extents_btree));
+}
+
+/*
+ * ssdfs_store_sb_segs_array() - store sb segments array
+ * @fsi: pointer on shared file system object
+ * @vh: volume header
+ */
+static inline
+void ssdfs_store_sb_segs_array(struct ssdfs_fs_info *fsi,
+				struct ssdfs_volume_header *vh)
+{
+	int i, j;
+
+#ifdef CONFIG_SSDFS_DEBUG
+	SSDFS_DBG("fsi %p, vh %p\n", fsi, vh);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	down_read(&fsi->sb_segs_sem);
+
+	for (i = SSDFS_CUR_SB_SEG; i < SSDFS_SB_CHAIN_MAX; i++) {
+		for (j = SSDFS_MAIN_SB_SEG; j < SSDFS_SB_SEG_COPY_MAX; j++) {
+			vh->sb_pebs[i][j].leb_id =
+				cpu_to_le64(fsi->sb_lebs[i][j]);
+			vh->sb_pebs[i][j].peb_id =
+				cpu_to_le64(fsi->sb_pebs[i][j]);
+		}
+	}
+
+	up_read(&fsi->sb_segs_sem);
+
+#ifdef CONFIG_SSDFS_DEBUG
+	SSDFS_DBG("sb_lebs[CUR][MAIN] %llu, sb_pebs[CUR][MAIN] %llu\n",
+		  fsi->sb_lebs[SSDFS_CUR_SB_SEG][SSDFS_MAIN_SB_SEG],
+		  fsi->sb_pebs[SSDFS_CUR_SB_SEG][SSDFS_MAIN_SB_SEG]);
+	SSDFS_DBG("sb_lebs[CUR][COPY] %llu, sb_pebs[CUR][COPY] %llu\n",
+		  fsi->sb_lebs[SSDFS_CUR_SB_SEG][SSDFS_COPY_SB_SEG],
+		  fsi->sb_pebs[SSDFS_CUR_SB_SEG][SSDFS_COPY_SB_SEG]);
+	SSDFS_DBG("sb_lebs[NEXT][MAIN] %llu, sb_pebs[NEXT][MAIN] %llu\n",
+		  fsi->sb_lebs[SSDFS_NEXT_SB_SEG][SSDFS_MAIN_SB_SEG],
+		  fsi->sb_pebs[SSDFS_NEXT_SB_SEG][SSDFS_MAIN_SB_SEG]);
+	SSDFS_DBG("sb_lebs[NEXT][COPY] %llu, sb_pebs[NEXT][COPY] %llu\n",
+		  fsi->sb_lebs[SSDFS_NEXT_SB_SEG][SSDFS_COPY_SB_SEG],
+		  fsi->sb_pebs[SSDFS_NEXT_SB_SEG][SSDFS_COPY_SB_SEG]);
+	SSDFS_DBG("sb_lebs[RESERVED][MAIN] %llu, sb_pebs[RESERVED][MAIN] %llu\n",
+		  fsi->sb_lebs[SSDFS_RESERVED_SB_SEG][SSDFS_MAIN_SB_SEG],
+		  fsi->sb_pebs[SSDFS_RESERVED_SB_SEG][SSDFS_MAIN_SB_SEG]);
+	SSDFS_DBG("sb_lebs[RESERVED][COPY] %llu, sb_pebs[RESERVED][COPY] %llu\n",
+		  fsi->sb_lebs[SSDFS_RESERVED_SB_SEG][SSDFS_COPY_SB_SEG],
+		  fsi->sb_pebs[SSDFS_RESERVED_SB_SEG][SSDFS_COPY_SB_SEG]);
+	SSDFS_DBG("sb_lebs[PREV][MAIN] %llu, sb_pebs[PREV][MAIN] %llu\n",
+		  fsi->sb_lebs[SSDFS_PREV_SB_SEG][SSDFS_MAIN_SB_SEG],
+		  fsi->sb_pebs[SSDFS_PREV_SB_SEG][SSDFS_MAIN_SB_SEG]);
+	SSDFS_DBG("sb_lebs[PREV][COPY] %llu, sb_pebs[PREV][COPY] %llu\n",
+		  fsi->sb_lebs[SSDFS_PREV_SB_SEG][SSDFS_COPY_SB_SEG],
+		  fsi->sb_pebs[SSDFS_PREV_SB_SEG][SSDFS_COPY_SB_SEG]);
+#endif /* CONFIG_SSDFS_DEBUG */
+}
+
+/*
+ * ssdfs_prepare_volume_header_for_commit() - prepare volume header for commit
+ * @fsi: pointer on shared file system object
+ * @vh: volume header
+ */
+int ssdfs_prepare_volume_header_for_commit(struct ssdfs_fs_info *fsi,
+					   struct ssdfs_volume_header *vh)
+{
+#ifdef CONFIG_SSDFS_DEBUG
+	struct super_block *sb = fsi->sb;
+	u64 dev_size;
+
+	SSDFS_DBG("fsi %p, vh %p\n", fsi, vh);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	ssdfs_store_sb_segs_array(fsi, vh);
+
+#ifdef CONFIG_SSDFS_DEBUG
+	dev_size = fsi->devops->device_size(sb);
+	if (!is_ssdfs_volume_header_consistent(fsi, vh, dev_size)) {
+		SSDFS_ERR("volume header is inconsistent\n");
+		return -EIO;
+	}
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	return 0;
+}
+
+/*
+ * ssdfs_prepare_segment_header_for_commit() - prepare segment header
+ * @fsi: pointer on shared file system object
+ * @log_pages: full log pages count
+ * @seg_type: segment type
+ * @seg_flags: segment flags
+ * @last_log_time: log creation time
+ * @last_log_cno: log checkpoint
+ * @hdr: segment header [out]
+ */
+int ssdfs_prepare_segment_header_for_commit(struct ssdfs_fs_info *fsi,
+					    u32 log_pages,
+					    u16 seg_type,
+					    u32 seg_flags,
+					    u64 last_log_time,
+					    u64 last_log_cno,
+					    struct ssdfs_segment_header *hdr)
+{
+	u16 data_size = sizeof(struct ssdfs_segment_header);
+	int err;
+
+#ifdef CONFIG_SSDFS_DEBUG
+	SSDFS_DBG("fsi %p, hdr %p, "
+		  "log_pages %u, seg_type %#x, seg_flags %#x\n",
+		  fsi, hdr, log_pages, seg_type, seg_flags);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	hdr->timestamp = cpu_to_le64(last_log_time);
+	hdr->cno = cpu_to_le64(last_log_cno);
+
+	if (log_pages > fsi->pages_per_seg || log_pages > U16_MAX) {
+		SSDFS_ERR("invalid value of log_pages %u\n", log_pages);
+		return -EINVAL;
+	}
+
+	hdr->log_pages = cpu_to_le16((u16)log_pages);
+
+	if (seg_type == SSDFS_UNKNOWN_SEG_TYPE ||
+	    seg_type > SSDFS_LAST_KNOWN_SEG_TYPE) {
+		SSDFS_ERR("invalid value of seg_type %#x\n", seg_type);
+		return -EINVAL;
+	}
+
+	hdr->seg_type = cpu_to_le16(seg_type);
+	hdr->seg_flags = cpu_to_le32(seg_flags);
+
+	hdr->volume_hdr.check.bytes = cpu_to_le16(data_size);
+	hdr->volume_hdr.check.flags = cpu_to_le16(SSDFS_CRC32);
+
+	err = ssdfs_calculate_csum(&hdr->volume_hdr.check,
+				   hdr, data_size);
+	if (unlikely(err)) {
+		SSDFS_ERR("unable to calculate checksum: err %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
+
+/*
+ * ssdfs_prepare_partial_log_header_for_commit() - prepare partial log header
+ * @fsi: pointer on shared file system object
+ * @sequence_id: sequence ID of the partial log inside the full log
+ * @log_pages: log pages count
+ * @seg_type: segment type
+ * @pl_flags: partial log's flags
+ * @last_log_time: log creation time
+ * @last_log_cno: log checkpoint
+ * @hdr: partial log's header [out]
+ */
+int ssdfs_prepare_partial_log_header_for_commit(struct ssdfs_fs_info *fsi,
+					int sequence_id,
+					u32 log_pages,
+					u16 seg_type,
+					u32 pl_flags,
+					u64 last_log_time,
+					u64 last_log_cno,
+					struct ssdfs_partial_log_header *hdr)
+{
+	u16 data_size = sizeof(struct ssdfs_partial_log_header);
+	int err;
+
+#ifdef CONFIG_SSDFS_DEBUG
+	SSDFS_DBG("fsi %p, hdr %p, sequence_id %d, "
+		  "log_pages %u, seg_type %#x, pl_flags %#x\n",
+		  fsi, hdr, sequence_id, log_pages, seg_type, pl_flags);
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	hdr->magic.common = cpu_to_le32(SSDFS_SUPER_MAGIC);
+	hdr->magic.key = cpu_to_le16(SSDFS_PARTIAL_LOG_HDR_MAGIC);
+	hdr->magic.version.major = SSDFS_MAJOR_REVISION;
+	hdr->magic.version.minor = SSDFS_MINOR_REVISION;
+
+	hdr->timestamp = cpu_to_le64(last_log_time);
+	hdr->cno = cpu_to_le64(last_log_cno);
+
+	if (log_pages > fsi->pages_per_seg || log_pages > U16_MAX) {
+		SSDFS_ERR("invalid value of log_pages %u\n", log_pages);
+		return -EINVAL;
+	}
+
+	hdr->log_pages = cpu_to_le16((u16)log_pages);
+	hdr->log_bytes = cpu_to_le32(log_pages << fsi->log_pagesize);
+
+	if (seg_type == SSDFS_UNKNOWN_SEG_TYPE ||
+	    seg_type > SSDFS_LAST_KNOWN_SEG_TYPE) {
+		SSDFS_ERR("invalid value of seg_type %#x\n", seg_type);
+		return -EINVAL;
+	}
+
+	hdr->seg_type = cpu_to_le16(seg_type);
+	hdr->pl_flags = cpu_to_le32(pl_flags);
+
+	spin_lock(&fsi->volume_state_lock);
+	hdr->free_pages = cpu_to_le64(fsi->free_pages);
+	hdr->flags = cpu_to_le32(fsi->fs_flags);
+	spin_unlock(&fsi->volume_state_lock);
+
+	mutex_lock(&fsi->resize_mutex);
+	hdr->nsegs = cpu_to_le64(fsi->nsegs);
+	mutex_unlock(&fsi->resize_mutex);
+
+	ssdfs_memcpy(&hdr->root_folder,
+		     0, sizeof(struct ssdfs_inode),
+		     &fsi->vs->root_folder,
+		     0, sizeof(struct ssdfs_inode),
+		     sizeof(struct ssdfs_inode));
+
+	ssdfs_memcpy(&hdr->inodes_btree,
+		     0, sizeof(struct ssdfs_inodes_btree),
+		     &fsi->vs->inodes_btree,
+		     0, sizeof(struct ssdfs_inodes_btree),
+		     sizeof(struct ssdfs_inodes_btree));
+	ssdfs_memcpy(&hdr->shared_extents_btree,
+		     0, sizeof(struct ssdfs_shared_extents_btree),
+		     &fsi->vs->shared_extents_btree,
+		     0, sizeof(struct ssdfs_shared_extents_btree),
+		     sizeof(struct ssdfs_shared_extents_btree));
+	ssdfs_memcpy(&hdr->shared_dict_btree,
+		     0, sizeof(struct ssdfs_shared_dictionary_btree),
+		     &fsi->vs->shared_dict_btree,
+		     0, sizeof(struct ssdfs_shared_dictionary_btree),
+		     sizeof(struct ssdfs_shared_dictionary_btree));
+	ssdfs_memcpy(&hdr->snapshots_btree,
+		     0, sizeof(struct ssdfs_snapshots_btree),
+		     &fsi->vs->snapshots_btree,
+		     0, sizeof(struct ssdfs_snapshots_btree),
+		     sizeof(struct ssdfs_snapshots_btree));
+	ssdfs_memcpy(&hdr->invextree,
+		     0, sizeof(struct ssdfs_invalidated_extents_btree),
+		     &fsi->vh->invextree,
+		     0, sizeof(struct ssdfs_invalidated_extents_btree),
+		     sizeof(struct ssdfs_invalidated_extents_btree));
+
+	hdr->sequence_id = cpu_to_le32(sequence_id);
+
+	hdr->log_pagesize = fsi->log_pagesize;
+	hdr->log_erasesize = fsi->log_erasesize;
+	hdr->log_segsize = fsi->log_segsize;
+	hdr->log_pebs_per_seg = fsi->log_pebs_per_seg;
+	hdr->lebs_per_peb_index = cpu_to_le32(fsi->lebs_per_peb_index);
+	hdr->create_threads_per_seg = cpu_to_le16(fsi->create_threads_per_seg);
+
+	hdr->open_zones = cpu_to_le32(atomic_read(&fsi->open_zones));
+
+#ifdef CONFIG_SSDFS_DEBUG
+	SSDFS_DBG("open_zones %d\n",
+		  atomic_read(&fsi->open_zones));
+#endif /* CONFIG_SSDFS_DEBUG */
+
+	hdr->check.bytes = cpu_to_le16(data_size);
+	hdr->check.flags = cpu_to_le16(SSDFS_CRC32);
+
+	err = ssdfs_calculate_csum(&hdr->check,
+				   hdr, data_size);
+	if (unlikely(err)) {
+		SSDFS_ERR("unable to calculate checksum: err %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
-- 
2.34.1