€•Šb      Œsphinx.addnodes”Œdocument”“”)”}”(Œ	rawsource”Œ ”Œchildren”]”(Œtranslations”ŒLanguagesNode”“”)”}”(hhh]”(h Œpending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ
attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ	refdomain”Œstd”Œreftype”Œdoc”Œ	reftarget”Œ$/translations/zh_CN/filesystems/qnx6”Œmodname”NŒ	classname”NŒrefexplicit”ˆuŒtagname”hhhubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ$/translations/zh_TW/filesystems/qnx6”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ$/translations/it_IT/filesystems/qnx6”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ$/translations/ja_JP/filesystems/qnx6”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ$/translations/ko_KR/filesystems/qnx6”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒPortuguese (Brazilian)”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ$/translations/pt_BR/filesystems/qnx6”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh–sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ$/translations/sp_SP/filesystems/qnx6”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒcomment”“”)”}”(hŒ SPDX-License-Identifier: GPL-2.0”h]”hŒ SPDX-License-Identifier: GPL-2.0”…””}”hh·sbah}”(h]”h ]”h"]”h$]”h&]”Œ	xml:space”Œpreserve”uh1hµhhh²hh³Œ>/var/lib/git/docbuild/linux/Documentation/filesystems/qnx6.rst”h´KubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒThe QNX6 Filesystem”h]”hŒThe QNX6 Filesystem”…””}”(hhÏh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhhÊh²hh³hÇh´KubhŒ	paragraph”“”)”}”(hŒŠThe qnx6fs is used by newer QNX operating system versions. (e.g. Neutrino)
It got introduced in QNX 6.4.0 and is used default since 6.4.1.”h]”hŒŠThe qnx6fs is used by newer QNX operating system versions. (e.g. Neutrino)
It got introduced in QNX 6.4.0 and is used default since 6.4.1.”…””}”(hhßh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KhhÊh²hubhÉ)”}”(hhh]”(hÎ)”}”(hŒOption”h]”hŒOption”…””}”(hhðh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhhíh²hh³hÇh´KubhÞ)”}”(hŒJmmi_fs          Mount filesystem as used for example by Audi MMI 3G system”h]”hŒJmmi_fs          Mount filesystem as used for example by Audi MMI 3G system”…””}”(hhþh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´Khhíh²hubeh}”(h]”Œoption”ah ]”h"]”Œoption”ah$]”h&]”uh1hÈhhÊh²hh³hÇh´KubhÉ)”}”(hhh]”(hÎ)”}”(hŒSpecification”h]”hŒSpecification”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhj  h²hh³hÇh´KubhÞ)”}”(hŒwqnx6fs shares many properties with traditional Unix filesystems. It has the
concepts of blocks, inodes and directories.”h]”hŒwqnx6fs shares many properties with traditional Unix filesystems. It has the
concepts of blocks, inodes and directories.”…””}”(hj%  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´Khj  h²hubhÞ)”}”(hX  On QNX it is possible to create little endian and big endian qnx6 filesystems.
This feature makes it possible to create and use a different endianness fs
for the target (QNX is used on quite a range of embedded systems) platform
running on a different endianness.”h]”hX  On QNX it is possible to create little endian and big endian qnx6 filesystems.
This feature makes it possible to create and use a different endianness fs
for the target (QNX is used on quite a range of embedded systems) platform
running on a different endianness.”…””}”(hj3  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´Khj  h²hubhÞ)”}”(hŒ>The Linux driver handles endianness transparently. (LE and BE)”h]”hŒ>The Linux driver handles endianness transparently. (LE and BE)”…””}”(hjA  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´Khj  h²hubhÉ)”}”(hhh]”(hÎ)”}”(hŒBlocks”h]”hŒBlocks”…””}”(hjR  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhjO  h²hh³hÇh´KubhÞ)”}”(hŒœThe space in the device or file is split up into blocks. These are a fixed
size of 512, 1024, 2048 or 4096, which is decided when the filesystem is
created.”h]”hŒœThe space in the device or file is split up into blocks. These are a fixed
size of 512, 1024, 2048 or 4096, which is decided when the filesystem is
created.”…””}”(hj`  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KhjO  h²hubhÞ)”}”(hŒ`Blockpointers are 32bit, so the maximum space that can be addressed is
2^32 * 4096 bytes or 16TB”h]”hŒ`Blockpointers are 32bit, so the maximum space that can be addressed is
2^32 * 4096 bytes or 16TB”…””}”(hjn  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K#hjO  h²hubeh}”(h]”Œblocks”ah ]”h"]”Œblocks”ah$]”h&]”uh1hÈhj  h²hh³hÇh´KubhÉ)”}”(hhh]”(hÎ)”}”(hŒThe superblocks”h]”hŒThe superblocks”…””}”(hj‡  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhj„  h²hh³hÇh´K'ubhÞ)”}”(hXc  The superblock contains all global information about the filesystem.
Each qnx6fs got two superblocks, each one having a 64bit serial number.
That serial number is used to identify the "active" superblock.
In write mode with reach new snapshot (after each synchronous write), the
serial of the new master superblock is increased (old superblock serial + 1)”h]”hXg  The superblock contains all global information about the filesystem.
Each qnx6fs got two superblocks, each one having a 64bit serial number.
That serial number is used to identify the â€œactiveâ€ superblock.
In write mode with reach new snapshot (after each synchronous write), the
serial of the new master superblock is increased (old superblock serial + 1)”…””}”(hj•  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K)hj„  h²hubhÞ)”}”(hX<  So basically the snapshot functionality is realized by an atomic final
update of the serial number. Before updating that serial, all modifications
are done by copying all modified blocks during that specific write request
(or period) and building up a new (stable) filesystem structure under the
inactive superblock.”h]”hX<  So basically the snapshot functionality is realized by an atomic final
update of the serial number. Before updating that serial, all modifications
are done by copying all modified blocks during that specific write request
(or period) and building up a new (stable) filesystem structure under the
inactive superblock.”…””}”(hj£  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K/hj„  h²hubhÞ)”}”(hX>  Each superblock holds a set of root inodes for the different filesystem
parts. (Inode, Bitmap and Longfilenames)
Each of these root nodes holds information like total size of the stored
data and the addressing levels in that specific tree.
If the level value is 0, up to 16 direct blocks can be addressed by each
node.”h]”hX>  Each superblock holds a set of root inodes for the different filesystem
parts. (Inode, Bitmap and Longfilenames)
Each of these root nodes holds information like total size of the stored
data and the addressing levels in that specific tree.
If the level value is 0, up to 16 direct blocks can be addressed by each
node.”…””}”(hj±  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K5hj„  h²hubhÞ)”}”(hX'  Level 1 adds an additional indirect addressing level where each indirect
addressing block holds up to blocksize / 4 bytes pointers to data blocks.
Level 2 adds an additional indirect addressing block level (so, already up
to 16 * 256 * 256 = 1048576 blocks that can be addressed by such a tree).”h]”hX'  Level 1 adds an additional indirect addressing level where each indirect
addressing block holds up to blocksize / 4 bytes pointers to data blocks.
Level 2 adds an additional indirect addressing block level (so, already up
to 16 * 256 * 256 = 1048576 blocks that can be addressed by such a tree).”…””}”(hj¿  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K<hj„  h²hubhÞ)”}”(hŒkUnused block pointers are always set to ~0 - regardless of root node,
indirect addressing blocks or inodes.”h]”hŒkUnused block pointers are always set to ~0 - regardless of root node,
indirect addressing blocks or inodes.”…””}”(hjÍ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KAhj„  h²hubhÞ)”}”(hŒVData leaves are always on the lowest level. So no data is stored on upper
tree levels.”h]”hŒVData leaves are always on the lowest level. So no data is stored on upper
tree levels.”…””}”(hjÛ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KDhj„  h²hubhÞ)”}”(hŒ…The first Superblock is located at 0x2000. (0x2000 is the bootblock size)
The Audi MMI 3G first superblock directly starts at byte 0.”h]”hŒ…The first Superblock is located at 0x2000. (0x2000 is the bootblock size)
The Audi MMI 3G first superblock directly starts at byte 0.”…””}”(hjé  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KGhj„  h²hubhÞ)”}”(hŒèSecond superblock position can either be calculated from the superblock
information (total number of filesystem blocks) or by taking the highest
device address, zeroing the last 3 bytes and then subtracting 0x1000 from
that address.”h]”hŒèSecond superblock position can either be calculated from the superblock
information (total number of filesystem blocks) or by taking the highest
device address, zeroing the last 3 bytes and then subtracting 0x1000 from
that address.”…””}”(hj÷  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KJhj„  h²hubhÞ)”}”(hŒ`0x1000 is the size reserved for each superblock - regardless of the
blocksize of the filesystem.”h]”hŒ`0x1000 is the size reserved for each superblock - regardless of the
blocksize of the filesystem.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KOhj„  h²hubeh}”(h]”Œthe-superblocks”ah ]”h"]”Œthe superblocks”ah$]”h&]”uh1hÈhj  h²hh³hÇh´K'ubhÉ)”}”(hhh]”(hÎ)”}”(hŒInodes”h]”hŒInodes”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhj  h²hh³hÇh´KSubhÞ)”}”(hX«  Each object in the filesystem is represented by an inode. (index node)
The inode structure contains pointers to the filesystem blocks which contain
the data held in the object and all of the metadata about an object except
its longname. (filenames longer than 27 characters)
The metadata about an object includes the permissions, owner, group, flags,
size, number of blocks used, access time, change time and modification time.”h]”hX«  Each object in the filesystem is represented by an inode. (index node)
The inode structure contains pointers to the filesystem blocks which contain
the data held in the object and all of the metadata about an object except
its longname. (filenames longer than 27 characters)
The metadata about an object includes the permissions, owner, group, flags,
size, number of blocks used, access time, change time and modification time.”…””}”(hj,  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KUhj  h²hubhÞ)”}”(hŒ>Object mode field is POSIX format. (which makes things easier)”h]”hŒ>Object mode field is POSIX format. (which makes things easier)”…””}”(hj:  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K\hj  h²hubhÞ)”}”(hŒjThere are also pointers to the first 16 blocks, if the object data can be
addressed with 16 direct blocks.”h]”hŒjThere are also pointers to the first 16 blocks, if the object data can be
addressed with 16 direct blocks.”…””}”(hjH  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K^hj  h²hubhÞ)”}”(hŒ’For more than 16 blocks an indirect addressing in form of another tree is
used. (scheme is the same as the one used for the superblock root nodes)”h]”hŒ’For more than 16 blocks an indirect addressing in form of another tree is
used. (scheme is the same as the one used for the superblock root nodes)”…””}”(hjV  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´Kahj  h²hubhÞ)”}”(hŒeThe filesize is stored 64bit. Inode counting starts with 1. (while long
filename inodes start with 0)”h]”hŒeThe filesize is stored 64bit. Inode counting starts with 1. (while long
filename inodes start with 0)”…””}”(hjd  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´Kdhj  h²hubeh}”(h]”Œinodes”ah ]”h"]”Œinodes”ah$]”h&]”uh1hÈhj  h²hh³hÇh´KSubhÉ)”}”(hhh]”(hÎ)”}”(hŒDirectories”h]”hŒDirectories”…””}”(hj}  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhjz  h²hh³hÇh´KhubhÞ)”}”(hŒ©A directory is a filesystem object and has an inode just like a file.
It is a specially formatted file containing records which associate each
name with an inode number.”h]”hŒ©A directory is a filesystem object and has an inode just like a file.
It is a specially formatted file containing records which associate each
name with an inode number.”…””}”(hj‹  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´Kjhjz  h²hubhÞ)”}”(hŒ.'.' inode number points to the directory inode”h]”hŒ2â€˜.â€™ inode number points to the directory inode”…””}”(hj™  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´Knhjz  h²hubhÞ)”}”(hŒ6'..' inode number points to the parent directory inode”h]”hŒ:â€˜..â€™ inode number points to the parent directory inode”…””}”(hj§  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´Kphjz  h²hubhÞ)”}”(hŒ?Eeach filename record additionally got a filename length field.”h]”hŒ?Eeach filename record additionally got a filename length field.”…””}”(hjµ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´Krhjz  h²hubhÞ)”}”(hŒ:One special case are long filenames or subdirectory names.”h]”hŒ:One special case are long filenames or subdirectory names.”…””}”(hjÃ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´Kthjz  h²hubhÞ)”}”(hŒŽThese got set a filename length field of 0xff in the corresponding directory
record plus the longfile inode number also stored in that record.”h]”hŒŽThese got set a filename length field of 0xff in the corresponding directory
record plus the longfile inode number also stored in that record.”…””}”(hjÑ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´Kvhjz  h²hubhÞ)”}”(hŒ†With that longfilename inode number, the longfilename tree can be walked
starting with the superblock longfilename root node pointers.”h]”hŒ†With that longfilename inode number, the longfilename tree can be walked
starting with the superblock longfilename root node pointers.”…””}”(hjß  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´Kyhjz  h²hubeh}”(h]”Œdirectories”ah ]”h"]”Œdirectories”ah$]”h&]”uh1hÈhj  h²hh³hÇh´KhubhÉ)”}”(hhh]”(hÎ)”}”(hŒSpecial files”h]”hŒSpecial files”…””}”(hjø  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhjõ  h²hh³hÇh´K}ubhÞ)”}”(hŒŠSymbolic links are also filesystem objects with inodes. They got a specific
bit in the inode mode field identifying them as symbolic link.”h]”hŒŠSymbolic links are also filesystem objects with inodes. They got a specific
bit in the inode mode field identifying them as symbolic link.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´Khjõ  h²hubhÞ)”}”(hŒGThe directory entry file inode pointer points to the target file inode.”h]”hŒGThe directory entry file inode pointer points to the target file inode.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K‚hjõ  h²hubhÞ)”}”(hŒ›Hard links got an inode, a directory entry, but a specific mode bit set,
no block pointers and the directory file record pointing to the target file
inode.”h]”hŒ›Hard links got an inode, a directory entry, but a specific mode bit set,
no block pointers and the directory file record pointing to the target file
inode.”…””}”(hj"  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K„hjõ  h²hubhÞ)”}”(hŒªCharacter and block special devices do not exist in QNX as those files
are handled by the QNX kernel/drivers and created in /dev independent of the
underlying filesystem.”h]”hŒªCharacter and block special devices do not exist in QNX as those files
are handled by the QNX kernel/drivers and created in /dev independent of the
underlying filesystem.”…””}”(hj0  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´Kˆhjõ  h²hubeh}”(h]”Œspecial-files”ah ]”h"]”Œspecial files”ah$]”h&]”uh1hÈhj  h²hh³hÇh´K}ubhÉ)”}”(hhh]”(hÎ)”}”(hŒLong filenames”h]”hŒLong filenames”…””}”(hjI  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhjF  h²hh³hÇh´KubhÞ)”}”(hŒ‚Long filenames are stored in a separate addressing tree. The staring point
is the longfilename root node in the active superblock.”h]”hŒ‚Long filenames are stored in a separate addressing tree. The staring point
is the longfilename root node in the active superblock.”…””}”(hjW  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KhjF  h²hubhÞ)”}”(hŒ¬Each data block (tree leaves) holds one long filename. That filename is
limited to 510 bytes. The first two starting bytes are used as length field
for the actual filename.”h]”hŒ¬Each data block (tree leaves) holds one long filename. That filename is
limited to 510 bytes. The first two starting bytes are used as length field
for the actual filename.”…””}”(hje  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K’hjF  h²hubhÞ)”}”(hŒ…If that structure shall fit for all allowed blocksizes, it is clear why there
is a limit of 510 bytes for the actual filename stored.”h]”hŒ…If that structure shall fit for all allowed blocksizes, it is clear why there
is a limit of 510 bytes for the actual filename stored.”…””}”(hjs  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K–hjF  h²hubeh}”(h]”Œlong-filenames”ah ]”h"]”Œlong filenames”ah$]”h&]”uh1hÈhj  h²hh³hÇh´KubhÉ)”}”(hhh]”(hÎ)”}”(hŒBitmap”h]”hŒBitmap”…””}”(hjŒ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhj‰  h²hh³hÇh´KšubhÞ)”}”(hŒ The qnx6fs filesystem allocation bitmap is stored in a tree under bitmap
root node in the superblock and each bit in the bitmap represents one
filesystem block.”h]”hŒ The qnx6fs filesystem allocation bitmap is stored in a tree under bitmap
root node in the superblock and each bit in the bitmap represents one
filesystem block.”…””}”(hjš  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´Kœhj‰  h²hubhÞ)”}”(hŒ³The first block is block 0, which starts 0x1000 after superblock start.
So for a normal qnx6fs 0x3000 (bootblock + superblock) is the physical
address at which block 0 is located.”h]”hŒ³The first block is block 0, which starts 0x1000 after superblock start.
So for a normal qnx6fs 0x3000 (bootblock + superblock) is the physical
address at which block 0 is located.”…””}”(hj¨  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K hj‰  h²hubhÞ)”}”(hŒtBits at the end of the last bitmap block are set to 1, if the device is
smaller than addressing space in the bitmap.”h]”hŒtBits at the end of the last bitmap block are set to 1, if the device is
smaller than addressing space in the bitmap.”…””}”(hj¶  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K¤hj‰  h²hubeh}”(h]”Œbitmap”ah ]”h"]”Œbitmap”ah$]”h&]”uh1hÈhj  h²hh³hÇh´KšubhÉ)”}”(hhh]”(hÎ)”}”(hŒBitmap system area”h]”hŒBitmap system area”…””}”(hjÏ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhjÌ  h²hh³hÇh´K¨ubhÞ)”}”(hŒ.The bitmap itself is divided into three parts.”h]”hŒ.The bitmap itself is divided into three parts.”…””}”(hjÝ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KªhjÌ  h²hubhÞ)”}”(hŒ5First the system area, that is split into two halves.”h]”hŒ5First the system area, that is split into two halves.”…””}”(hjë  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K¬hjÌ  h²hubhÞ)”}”(hŒThen userspace.”h]”hŒThen userspace.”…””}”(hjù  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K®hjÌ  h²hubhÞ)”}”(hŒeThe requirement for a static, fixed preallocated system area comes from how
qnx6fs deals with writes.”h]”hŒeThe requirement for a static, fixed preallocated system area comes from how
qnx6fs deals with writes.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K°hjÌ  h²hubhÞ)”}”(hŒÍEach superblock got its own half of the system area. So superblock #1
always uses blocks from the lower half while superblock #2 just writes to
blocks represented by the upper half bitmap system area bits.”h]”hŒÍEach superblock got its own half of the system area. So superblock #1
always uses blocks from the lower half while superblock #2 just writes to
blocks represented by the upper half bitmap system area bits.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K³hjÌ  h²hubhÞ)”}”(hŒvBitmap blocks, Inode blocks and indirect addressing blocks for those two
tree structures are treated as system blocks.”h]”hŒvBitmap blocks, Inode blocks and indirect addressing blocks for those two
tree structures are treated as system blocks.”…””}”(hj#  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K·hjÌ  h²hubhÞ)”}”(hX  The rational behind that is that a write request can work on a new snapshot
(system area of the inactive - resp. lower serial numbered superblock) while
at the same time there is still a complete stable filesystem structure in the
other half of the system area.”h]”hX  The rational behind that is that a write request can work on a new snapshot
(system area of the inactive - resp. lower serial numbered superblock) while
at the same time there is still a complete stable filesystem structure in the
other half of the system area.”…””}”(hj1  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KºhjÌ  h²hubhÞ)”}”(hX   When finished with writing (a sync write is completed, the maximum sync leap
time or a filesystem sync is requested), serial of the previously inactive
superblock atomically is increased and the fs switches over to that - then
stable declared - superblock.”h]”hX   When finished with writing (a sync write is completed, the maximum sync leap
time or a filesystem sync is requested), serial of the previously inactive
superblock atomically is increased and the fs switches over to that - then
stable declared - superblock.”…””}”(hj?  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´K¿hjÌ  h²hubhÞ)”}”(hŒKFor all data outside the system area, blocks are just copied while writing.”h]”hŒKFor all data outside the system area, blocks are just copied while writing.”…””}”(hjM  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝh³hÇh´KÄhjÌ  h²hubeh}”(h]”Œbitmap-system-area”ah ]”h"]”Œbitmap system area”ah$]”h&]”uh1hÈhj  h²hh³hÇh´K¨ubeh}”(h]”Œspecification”ah ]”h"]”Œspecification”ah$]”h&]”uh1hÈhhÊh²hh³hÇh´Kubeh}”(h]”Œthe-qnx6-filesystem”ah ]”h"]”Œthe qnx6 filesystem”ah$]”h&]”uh1hÈhhh²hh³hÇh´Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”hÇuh1hŒcurrent_source”NŒcurrent_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(hÍNŒ	generator”NŒ	datestamp”NŒsource_link”NŒ
source_url”NŒtoc_backlinks”Œentry”Œfootnote_backlinks”KŒsectnum_xform”KŒstrip_comments”NŒstrip_elements_with_classes”NŒstrip_classes”NŒreport_level”KŒ
halt_level”KŒexit_status_level”KŒdebug”NŒwarning_stream”NŒ	traceback”ˆŒinput_encoding”Œ	utf-8-sig”Œinput_encoding_error_handler”Œstrict”Œoutput_encoding”Œutf-8”Œoutput_encoding_error_handler”j–  Œerror_encoding”Œutf-8”Œerror_encoding_error_handler”Œbackslashreplace”Œlanguage_code”Œen”Œrecord_dependencies”NŒconfig”NŒ	id_prefix”hŒauto_id_prefix”Œid”Œdump_settings”NŒdump_internals”NŒdump_transforms”NŒdump_pseudo_xml”NŒexpose_internals”NŒstrict_visitor”NŒ_disable_config”NŒ_source”hÇŒ_destination”NŒ_config_files”]”Œ7/var/lib/git/docbuild/linux/Documentation/docutils.conf”aŒfile_insertion_enabled”ˆŒraw_enabled”KŒline_length_limit”M'Œpep_references”NŒpep_base_url”Œhttps://peps.python.org/”Œpep_file_url_template”Œpep-%04d”Œrfc_references”NŒrfc_base_url”Œ&https://datatracker.ietf.org/doc/html/”Œ	tab_width”KŒtrim_footnote_reference_space”‰Œsyntax_highlight”Œlong”Œsmart_quotes”ˆŒsmartquotes_locales”]”Œcharacter_level_inline_markup”‰Œdoctitle_xform”‰Œdocinfo_xform”KŒsectsubtitle_xform”‰Œimage_loading”Œlink”Œembed_stylesheet”‰Œcloak_email_addresses”ˆŒsection_self_link”‰Œenv”NubŒreporter”NŒindirect_targets”]”Œsubstitution_defs”}”Œsubstitution_names”}”Œrefnames”}”Œrefids”}”Œnameids”}”(jp  jm  j  j  jh  je  j  j~  j  j  jw  jt  jò  jï  jC  j@  j†  jƒ  jÉ  jÆ  j`  j]  uŒ	nametypes”}”(jp  ‰j  ‰jh  ‰j  ‰j  ‰jw  ‰jò  ‰jC  ‰j†  ‰jÉ  ‰j`  ‰uh}”(jm  hÊj  híje  j  j~  jO  j  j„  jt  j  jï  jz  j@  jõ  jƒ  jF  jÆ  j‰  j]  jÌ  uŒfootnote_refs”}”Œcitation_refs”}”Œautofootnotes”]”Œautofootnote_refs”]”Œsymbol_footnotes”]”Œsymbol_footnote_refs”]”Œ	footnotes”]”Œ	citations”]”Œautofootnote_start”KŒsymbol_footnote_start”K Œ
id_counter”Œcollections”ŒCounter”“”}”…”R”Œparse_messages”]”Œtransform_messages”]”Œtransformer”NŒinclude_log”]”Œ
decoration”Nh²hub.