OSCL-LXR linux-6.0.1/​fs/​ntfs/​usnjrnl.h	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 /* SPDX-License-Identifier: GPL-2.0-or-later */
 /*
  * usnjrnl.h - Defines for NTFS kernel transaction log ($UsnJrnl) handling.
  *         Part of the Linux-NTFS project.
  *
  * Copyright (c) 2005 Anton Altaparmakov
  */
 
 #ifndef _LINUX_NTFS_USNJRNL_H
 #define _LINUX_NTFS_USNJRNL_H
 
 #ifdef NTFS_RW
 
 #include "types.h"
 #include "endian.h"
 #include "layout.h"
 #include "volume.h"
 
 /*
  * Transaction log ($UsnJrnl) organization:
  *
  * The transaction log records whenever a file is modified in any way.  So for
  * example it will record that file "blah" was written to at a particular time
  * but not what was written.  If will record that a file was deleted or
  * created, that a file was truncated, etc.  See below for all the reason
  * codes used.
  *
  * The transaction log is in the $Extend directory which is in the root
  * directory of each volume.  If it is not present it means transaction
  * logging is disabled.  If it is present it means transaction logging is
  * either enabled or in the process of being disabled in which case we can
  * ignore it as it will go away as soon as Windows gets its hands on it.
  *
  * To determine whether the transaction logging is enabled or in the process
  * of being disabled, need to check the volume flags in the
  * $VOLUME_INFORMATION attribute in the $Volume system file (which is present
  * in the root directory and has a fixed mft record number, see layout.h).
  * If the flag VOLUME_DELETE_USN_UNDERWAY is set it means the transaction log
  * is in the process of being disabled and if this flag is clear it means the
  * transaction log is enabled.
  *
  * The transaction log consists of two parts; the $DATA/$Max attribute as well
  * as the $DATA/$J attribute.  $Max is a header describing the transaction
  * log whilst $J is the transaction log data itself as a sequence of variable
  * sized USN_RECORDs (see below for all the structures).
  *
  * We do not care about transaction logging at this point in time but we still
  * need to let windows know that the transaction log is out of date.  To do
  * this we need to stamp the transaction log.  This involves setting the
  * lowest_valid_usn field in the $DATA/$Max attribute to the usn to be used
  * for the next added USN_RECORD to the $DATA/$J attribute as well as
  * generating a new journal_id in $DATA/$Max.
  *
  * The journal_id is as of the current version (2.0) of the transaction log
  * simply the 64-bit timestamp of when the journal was either created or last
  * stamped.
  *
  * To determine the next usn there are two ways.  The first is to parse
  * $DATA/$J and to find the last USN_RECORD in it and to add its record_length
  * to its usn (which is the byte offset in the $DATA/$J attribute).  The
  * second is simply to take the data size of the attribute.  Since the usns
  * are simply byte offsets into $DATA/$J, this is exactly the next usn.  For
  * obvious reasons we use the second method as it is much simpler and faster.
  *
  * As an aside, note that to actually disable the transaction log, one would
  * need to set the VOLUME_DELETE_USN_UNDERWAY flag (see above), then go
  * through all the mft records on the volume and set the usn field in their
  * $STANDARD_INFORMATION attribute to zero.  Once that is done, one would need
  * to delete the transaction log file, i.e. \$Extent\$UsnJrnl, and finally,
  * one would need to clear the VOLUME_DELETE_USN_UNDERWAY flag.
  *
  * Note that if a volume is unmounted whilst the transaction log is being
  * disabled, the process will continue the next time the volume is mounted.
  * This is why we can safely mount read-write when we see a transaction log
  * in the process of being deleted.
  */
 
 /* Some $UsnJrnl related constants. */
 #define UsnJrnlMajorVer     2
 #define UsnJrnlMinorVer     0
 
 /*
  * $DATA/$Max attribute.  This is (always?) resident and has a fixed size of
  * 32 bytes.  It contains the header describing the transaction log.
  */
 typedef struct {
 /*Ofs*/
 /*   0*/sle64 maximum_size; /* The maximum on-disk size of the $DATA/$J
                    attribute. */
 /*   8*/sle64 allocation_delta; /* Number of bytes by which to increase the
                    size of the $DATA/$J attribute. */
 /*0x10*/sle64 journal_id;   /* Current id of the transaction log. */
 /*0x18*/leUSN lowest_valid_usn; /* Lowest valid usn in $DATA/$J for the
                    current journal_id. */
 /* sizeof() = 32 (0x20) bytes */
 } __attribute__ ((__packed__)) USN_HEADER;
 
 /*
  * Reason flags (32-bit).  Cumulative flags describing the change(s) to the
  * file since it was last opened.  I think the names speak for themselves but
  * if you disagree check out the descriptions in the Linux NTFS project NTFS
  * documentation: http://www.linux-ntfs.org/
  */
 enum {
     USN_REASON_DATA_OVERWRITE   = cpu_to_le32(0x00000001),
     USN_REASON_DATA_EXTEND      = cpu_to_le32(0x00000002),
     USN_REASON_DATA_TRUNCATION  = cpu_to_le32(0x00000004),
     USN_REASON_NAMED_DATA_OVERWRITE = cpu_to_le32(0x00000010),
     USN_REASON_NAMED_DATA_EXTEND    = cpu_to_le32(0x00000020),
     USN_REASON_NAMED_DATA_TRUNCATION= cpu_to_le32(0x00000040),
     USN_REASON_FILE_CREATE      = cpu_to_le32(0x00000100),
     USN_REASON_FILE_DELETE      = cpu_to_le32(0x00000200),
     USN_REASON_EA_CHANGE        = cpu_to_le32(0x00000400),
     USN_REASON_SECURITY_CHANGE  = cpu_to_le32(0x00000800),
     USN_REASON_RENAME_OLD_NAME  = cpu_to_le32(0x00001000),
     USN_REASON_RENAME_NEW_NAME  = cpu_to_le32(0x00002000),
     USN_REASON_INDEXABLE_CHANGE = cpu_to_le32(0x00004000),
     USN_REASON_BASIC_INFO_CHANGE    = cpu_to_le32(0x00008000),
     USN_REASON_HARD_LINK_CHANGE = cpu_to_le32(0x00010000),
     USN_REASON_COMPRESSION_CHANGE   = cpu_to_le32(0x00020000),
     USN_REASON_ENCRYPTION_CHANGE    = cpu_to_le32(0x00040000),
     USN_REASON_OBJECT_ID_CHANGE = cpu_to_le32(0x00080000),
     USN_REASON_REPARSE_POINT_CHANGE = cpu_to_le32(0x00100000),
     USN_REASON_STREAM_CHANGE    = cpu_to_le32(0x00200000),
     USN_REASON_CLOSE        = cpu_to_le32(0x80000000),
 };
 
 typedef le32 USN_REASON_FLAGS;
 
 /*
  * Source info flags (32-bit).  Information about the source of the change(s)
  * to the file.  For detailed descriptions of what these mean, see the Linux
  * NTFS project NTFS documentation:
  *  http://www.linux-ntfs.org/
  */
 enum {
     USN_SOURCE_DATA_MANAGEMENT    = cpu_to_le32(0x00000001),
     USN_SOURCE_AUXILIARY_DATA     = cpu_to_le32(0x00000002),
     USN_SOURCE_REPLICATION_MANAGEMENT = cpu_to_le32(0x00000004),
 };
 
 typedef le32 USN_SOURCE_INFO_FLAGS;
 
 /*
  * $DATA/$J attribute.  This is always non-resident, is marked as sparse, and
  * is of variabled size.  It consists of a sequence of variable size
  * USN_RECORDS.  The minimum allocated_size is allocation_delta as
  * specified in $DATA/$Max.  When the maximum_size specified in $DATA/$Max is
  * exceeded by more than allocation_delta bytes, allocation_delta bytes are
  * allocated and appended to the $DATA/$J attribute and an equal number of
  * bytes at the beginning of the attribute are freed and made sparse.  Note the
  * making sparse only happens at volume checkpoints and hence the actual
  * $DATA/$J size can exceed maximum_size + allocation_delta temporarily.
  */
 typedef struct {
 /*Ofs*/
 /*   0*/le32 length;        /* Byte size of this record (8-byte
                    aligned). */
 /*   4*/le16 major_ver;     /* Major version of the transaction log used
                    for this record. */
 /*   6*/le16 minor_ver;     /* Minor version of the transaction log used
                    for this record. */
 /*   8*/leMFT_REF mft_reference;/* The mft reference of the file (or
                    directory) described by this record. */
 /*0x10*/leMFT_REF parent_directory;/* The mft reference of the parent
                    directory of the file described by this
                    record. */
 /*0x18*/leUSN usn;      /* The usn of this record.  Equals the offset
                    within the $DATA/$J attribute. */
 /*0x20*/sle64 time;     /* Time when this record was created. */
 /*0x28*/USN_REASON_FLAGS reason;/* Reason flags (see above). */
 /*0x2c*/USN_SOURCE_INFO_FLAGS source_info;/* Source info flags (see above). */
 /*0x30*/le32 security_id;   /* File security_id copied from
                    $STANDARD_INFORMATION. */
 /*0x34*/FILE_ATTR_FLAGS file_attributes;    /* File attributes copied from
                    $STANDARD_INFORMATION or $FILE_NAME (not
                    sure which). */
 /*0x38*/le16 file_name_size;    /* Size of the file name in bytes. */
 /*0x3a*/le16 file_name_offset;  /* Offset to the file name in bytes from the
                    start of this record. */
 /*0x3c*/ntfschar file_name[0];  /* Use when creating only.  When reading use
                    file_name_offset to determine the location
                    of the name. */
 /* sizeof() = 60 (0x3c) bytes */
 } __attribute__ ((__packed__)) USN_RECORD;
 
 extern bool ntfs_stamp_usnjrnl(ntfs_volume *vol);
 
 #endif /* NTFS_RW */
 
 #endif /* _LINUX_NTFS_USNJRNL_H */

This page was automatically generated by the 2.1.0 LXR engine. The LXR team