--- /dev/null
+/*
+ * logfile.h - Defines for NTFS kernel journal ($LogFile) handling. Part of
+ * the Linux-NTFS project.
+ *
+ * Copyright (c) 2000-2005 Anton Altaparmakov
+ *
+ * This program/include file is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program/include file is distributed in the hope that it will be
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program (in the main directory of the Linux-NTFS
+ * distribution in the file COPYING); if not, write to the Free Software
+ * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef _LINUX_NTFS_LOGFILE_H
+#define _LINUX_NTFS_LOGFILE_H
+
+#ifdef NTFS_RW
+
+#include <linux/fs.h>
+
+#include "types.h"
+#include "endian.h"
+#include "layout.h"
+
+/*
+ * Journal ($LogFile) organization:
+ *
+ * Two restart areas present in the first two pages (restart pages, one restart
+ * area in each page). When the volume is dismounted they should be identical,
+ * except for the update sequence array which usually has a different update
+ * sequence number.
+ *
+ * These are followed by log records organized in pages headed by a log record
+ * header going up to log file size. Not all pages contain log records when a
+ * volume is first formatted, but as the volume ages, all records will be used.
+ * When the log file fills up, the records at the beginning are purged (by
+ * modifying the oldest_lsn to a higher value presumably) and writing begins
+ * at the beginning of the file. Effectively, the log file is viewed as a
+ * circular entity.
+ *
+ * NOTE: Windows NT, 2000, and XP all use log file version 1.1 but they accept
+ * versions <= 1.x, including 0.-1. (Yes, that is a minus one in there!) We
+ * probably only want to support 1.1 as this seems to be the current version
+ * and we don't know how that differs from the older versions. The only
+ * exception is if the journal is clean as marked by the two restart pages
+ * then it doesn't matter whether we are on an earlier version. We can just
+ * reinitialize the logfile and start again with version 1.1.
+ */
+
+/* Some $LogFile related constants. */
+#define MaxLogFileSize 0x100000000ULL
+#define DefaultLogPageSize 4096
+#define MinLogRecordPages 48
+
+/*
+ * Log file restart page header (begins the restart area).
+ */
+typedef struct {
+/*Ofs*/
+/* 0 NTFS_RECORD; -- Unfolded here as gcc doesn't like unnamed structs. */
+/* 0*/ NTFS_RECORD_TYPE magic; /* The magic is "RSTR". */
+/* 4*/ le16 usa_ofs; /* See NTFS_RECORD definition in layout.h.
+ When creating, set this to be immediately
+ after this header structure (without any
+ alignment). */
+/* 6*/ le16 usa_count; /* See NTFS_RECORD definition in layout.h. */
+
+/* 8*/ leLSN chkdsk_lsn; /* The last log file sequence number found by
+ chkdsk. Only used when the magic is changed
+ to "CHKD". Otherwise this is zero. */
+/* 16*/ le32 system_page_size; /* Byte size of system pages when the log file
+ was created, has to be >= 512 and a power of
+ 2. Use this to calculate the required size
+ of the usa (usa_count) and add it to usa_ofs.
+ Then verify that the result is less than the
+ value of the restart_area_offset. */
+/* 20*/ le32 log_page_size; /* Byte size of log file pages, has to be >=
+ 512 and a power of 2. The default is 4096
+ and is used when the system page size is
+ between 4096 and 8192. Otherwise this is
+ set to the system page size instead. */
+/* 24*/ le16 restart_area_offset;/* Byte offset from the start of this header to
+ the RESTART_AREA. Value has to be aligned
+ to 8-byte boundary. When creating, set this
+ to be after the usa. */
+/* 26*/ sle16 minor_ver; /* Log file minor version. Only check if major
+ version is 1. */
+/* 28*/ sle16 major_ver; /* Log file major version. We only support
+ version 1.1. */
+/* sizeof() = 30 (0x1e) bytes */
+} __attribute__ ((__packed__)) RESTART_PAGE_HEADER;
+
+/*
+ * Constant for the log client indices meaning that there are no client records
+ * in this particular client array. Also inside the client records themselves,
+ * this means that there are no client records preceding or following this one.
+ */
+#define LOGFILE_NO_CLIENT cpu_to_le16(0xffff)
+#define LOGFILE_NO_CLIENT_CPU 0xffff
+
+/*
+ * These are the so far known RESTART_AREA_* flags (16-bit) which contain
+ * information about the log file in which they are present.
+ */
+enum {
+ RESTART_VOLUME_IS_CLEAN = cpu_to_le16(0x0002),
+ RESTART_SPACE_FILLER = cpu_to_le16(0xffff), /* gcc: Force enum bit width to 16. */
+} __attribute__ ((__packed__));
+
+typedef le16 RESTART_AREA_FLAGS;
+
+/*
+ * Log file restart area record. The offset of this record is found by adding
+ * the offset of the RESTART_PAGE_HEADER to the restart_area_offset value found
+ * in it. See notes at restart_area_offset above.
+ */
+typedef struct {
+/*Ofs*/
+/* 0*/ leLSN current_lsn; /* The current, i.e. last LSN inside the log
+ when the restart area was last written.
+ This happens often but what is the interval?
+ Is it just fixed time or is it every time a
+ check point is written or somethine else?
+ On create set to 0. */
+/* 8*/ le16 log_clients; /* Number of log client records in the array of
+ log client records which follows this
+ restart area. Must be 1. */
+/* 10*/ le16 client_free_list; /* The index of the first free log client record
+ in the array of log client records.
+ LOGFILE_NO_CLIENT means that there are no
+ free log client records in the array.
+ If != LOGFILE_NO_CLIENT, check that
+ log_clients > client_free_list. On Win2k
+ and presumably earlier, on a clean volume
+ this is != LOGFILE_NO_CLIENT, and it should
+ be 0, i.e. the first (and only) client
+ record is free and thus the logfile is
+ closed and hence clean. A dirty volume
+ would have left the logfile open and hence
+ this would be LOGFILE_NO_CLIENT. On WinXP
+ and presumably later, the logfile is always
+ open, even on clean shutdown so this should
+ always be LOGFILE_NO_CLIENT. */
+/* 12*/ le16 client_in_use_list;/* The index of the first in-use log client
+ record in the array of log client records.
+ LOGFILE_NO_CLIENT means that there are no
+ in-use log client records in the array. If
+ != LOGFILE_NO_CLIENT check that log_clients
+ > client_in_use_list. On Win2k and
+ presumably earlier, on a clean volume this
+ is LOGFILE_NO_CLIENT, i.e. there are no
+ client records in use and thus the logfile
+ is closed and hence clean. A dirty volume
+ would have left the logfile open and hence
+ this would be != LOGFILE_NO_CLIENT, and it
+ should be 0, i.e. the first (and only)
+ client record is in use. On WinXP and
+ presumably later, the logfile is always
+ open, even on clean shutdown so this should
+ always be 0. */
+/* 14*/ RESTART_AREA_FLAGS flags;/* Flags modifying LFS behaviour. On Win2k
+ and presumably earlier this is always 0. On
+ WinXP and presumably later, if the logfile
+ was shutdown cleanly, the second bit,
+ RESTART_VOLUME_IS_CLEAN, is set. This bit
+ is cleared when the volume is mounted by
+ WinXP and set when the volume is dismounted,
+ thus if the logfile is dirty, this bit is
+ clear. Thus we don't need to check the
+ Windows version to determine if the logfile
+ is clean. Instead if the logfile is closed,
+ we know it must be clean. If it is open and
+ this bit is set, we also know it must be
+ clean. If on the other hand the logfile is
+ open and this bit is clear, we can be almost
+ certain that the logfile is dirty. */
+/* 16*/ le32 seq_number_bits; /* How many bits to use for the sequence
+ number. This is calculated as 67 - the
+ number of bits required to store the logfile
+ size in bytes and this can be used in with
+ the specified file_size as a consistency
+ check. */
+/* 20*/ le16 restart_area_length;/* Length of the restart area including the
+ client array. Following checks required if
+ version matches. Otherwise, skip them.
+ restart_area_offset + restart_area_length
+ has to be <= system_page_size. Also,
+ restart_area_length has to be >=
+ client_array_offset + (log_clients *
+ sizeof(log client record)). */
+/* 22*/ le16 client_array_offset;/* Offset from the start of this record to
+ the first log client record if versions are
+ matched. When creating, set this to be
+ after this restart area structure, aligned
+ to 8-bytes boundary. If the versions do not
+ match, this is ignored and the offset is
+ assumed to be (sizeof(RESTART_AREA) + 7) &
+ ~7, i.e. rounded up to first 8-byte
+ boundary. Either way, client_array_offset
+ has to be aligned to an 8-byte boundary.
+ Also, restart_area_offset +
+ client_array_offset has to be <= 510.
+ Finally, client_array_offset + (log_clients
+ * sizeof(log client record)) has to be <=
+ system_page_size. On Win2k and presumably
+ earlier, this is 0x30, i.e. immediately
+ following this record. On WinXP and
+ presumably later, this is 0x40, i.e. there
+ are 16 extra bytes between this record and
+ the client array. This probably means that
+ the RESTART_AREA record is actually bigger
+ in WinXP and later. */
+/* 24*/ sle64 file_size; /* Usable byte size of the log file. If the
+ restart_area_offset + the offset of the
+ file_size are > 510 then corruption has
+ occurred. This is the very first check when
+ starting with the restart_area as if it
+ fails it means that some of the above values
+ will be corrupted by the multi sector
+ transfer protection. The file_size has to
+ be rounded down to be a multiple of the
+ log_page_size in the RESTART_PAGE_HEADER and
+ then it has to be at least big enough to
+ store the two restart pages and 48 (0x30)
+ log record pages. */
+/* 32*/ le32 last_lsn_data_length;/* Length of data of last LSN, not including
+ the log record header. On create set to
+ 0. */
+/* 36*/ le16 log_record_header_length;/* Byte size of the log record header.
+ If the version matches then check that the
+ value of log_record_header_length is a
+ multiple of 8, i.e.
+ (log_record_header_length + 7) & ~7 ==
+ log_record_header_length. When creating set
+ it to sizeof(LOG_RECORD_HEADER), aligned to
+ 8 bytes. */
+/* 38*/ le16 log_page_data_offset;/* Offset to the start of data in a log record
+ page. Must be a multiple of 8. On create
+ set it to immediately after the update
+ sequence array of the log record page. */
+/* 40*/ le32 restart_log_open_count;/* A counter that gets incremented every
+ time the logfile is restarted which happens
+ at mount time when the logfile is opened.
+ When creating set to a random value. Win2k
+ sets it to the low 32 bits of the current
+ system time in NTFS format (see time.h). */
+/* 44*/ le32 reserved; /* Reserved/alignment to 8-byte boundary. */
+/* sizeof() = 48 (0x30) bytes */
+} __attribute__ ((__packed__)) RESTART_AREA;
+
+/*
+ * Log client record. The offset of this record is found by adding the offset
+ * of the RESTART_AREA to the client_array_offset value found in it.
+ */
+typedef struct {
+/*Ofs*/
+/* 0*/ leLSN oldest_lsn; /* Oldest LSN needed by this client. On create
+ set to 0. */
+/* 8*/ leLSN client_restart_lsn;/* LSN at which this client needs to restart
+ the volume, i.e. the current position within
+ the log file. At present, if clean this
+ should = current_lsn in restart area but it
+ probably also = current_lsn when dirty most
+ of the time. At create set to 0. */
+/* 16*/ le16 prev_client; /* The offset to the previous log client record
+ in the array of log client records.
+ LOGFILE_NO_CLIENT means there is no previous
+ client record, i.e. this is the first one.
+ This is always LOGFILE_NO_CLIENT. */
+/* 18*/ le16 next_client; /* The offset to the next log client record in
+ the array of log client records.
+ LOGFILE_NO_CLIENT means there are no next
+ client records, i.e. this is the last one.
+ This is always LOGFILE_NO_CLIENT. */
+/* 20*/ le16 seq_number; /* On Win2k and presumably earlier, this is set
+ to zero every time the logfile is restarted
+ and it is incremented when the logfile is
+ closed at dismount time. Thus it is 0 when
+ dirty and 1 when clean. On WinXP and
+ presumably later, this is always 0. */
+/* 22*/ u8 reserved[6]; /* Reserved/alignment. */
+/* 28*/ le32 client_name_length;/* Length of client name in bytes. Should
+ always be 8. */
+/* 32*/ ntfschar client_name[64];/* Name of the client in Unicode. Should
+ always be "NTFS" with the remaining bytes
+ set to 0. */
+/* sizeof() = 160 (0xa0) bytes */
+} __attribute__ ((__packed__)) LOG_CLIENT_RECORD;
+
+extern bool ntfs_check_logfile(struct inode *log_vi,
+ RESTART_PAGE_HEADER **rp);
+
+extern bool ntfs_is_logfile_clean(struct inode *log_vi,
+ const RESTART_PAGE_HEADER *rp);
+
+extern bool ntfs_empty_logfile(struct inode *log_vi);
+
+#endif /* NTFS_RW */
+
+#endif /* _LINUX_NTFS_LOGFILE_H */
Code Review / kvmfornfv.git / blobdiff