Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:

 - further restructure ext4 documentation

 - fix up ext4's delayed allocation for bigalloc file systems

 - fix up some syzbot-detected races in EXT4_IOC_MOVE_EXT,
   EXT4_IOC_SWAP_BOOT, and ext4_remount

 - ... and a few other miscellaneous bugs and optimizations.

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (21 commits)
  ext4: fix use-after-free race in ext4_remount()'s error path
  ext4: cache NULL when both default_acl and acl are NULL
  docs: promote the ext4 data structures book to top level
  docs: move ext4 administrative docs to admin-guide/
  jbd2: fix use after free in jbd2_log_do_checkpoint()
  ext4: propagate error from dquot_initialize() in EXT4_IOC_FSSETXATTR
  ext4: fix setattr project check in fssetxattr ioctl
  docs: make ext4 readme tables readable
  docs: fix ext4 documentation table formatting problems
  docs: generate a separate ext4 pdf file from the documentation
  ext4: convert fault handler to use vm_fault_t type
  ext4: initialize retries variable in ext4_da_write_inline_data_begin()
  ext4: fix EXT4_IOC_SWAP_BOOT
  ext4: fix build error when DX_DEBUG is defined
  ext4: fix argument checking in EXT4_IOC_MOVE_EXT
  ext4: fix reserved cluster accounting at page invalidation time
  ext4: adjust reserved cluster count when removing extents
  ext4: reduce reserved cluster count by number of allocated clusters
  ext4: fix reserved cluster accounting at delayed write time
  ext4: add new pending reservation mechanism
  ...

28 files changed, 647 insertions, 692 deletions

diff --git a/Documentation/admin-guide/ext4.rst b/Documentation/admin-guide/ext4.rst
new file mode 100644
index 000000000000..e506d3dae510
--- /dev/null
+++ b/Documentation/admin-guide/ext4.rst
@@ -0,0 +1,574 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+========================
+ext4 General Information
+========================
+
+Ext4 is an advanced level of the ext3 filesystem which incorporates
+scalability and reliability enhancements for supporting large filesystems
+(64 bit) in keeping with increasing disk capacities and state-of-the-art
+feature requirements.
+
+Mailing list:	linux-ext4@vger.kernel.org
+Web site:	http://ext4.wiki.kernel.org
+
+
+Quick usage instructions
+========================
+
+Note: More extensive information for getting started with ext4 can be
+found at the ext4 wiki site at the URL:
+http://ext4.wiki.kernel.org/index.php/Ext4_Howto
+
+  - The latest version of e2fsprogs can be found at:
+
+    https://www.kernel.org/pub/linux/kernel/people/tytso/e2fsprogs/
+
+	or
+
+    http://sourceforge.net/project/showfiles.php?group_id=2406
+
+	or grab the latest git repository from:
+
+   https://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git
+
+  - Create a new filesystem using the ext4 filesystem type:
+
+        # mke2fs -t ext4 /dev/hda1
+
+    Or to configure an existing ext3 filesystem to support extents:
+
+	# tune2fs -O extents /dev/hda1
+
+    If the filesystem was created with 128 byte inodes, it can be
+    converted to use 256 byte for greater efficiency via:
+
+        # tune2fs -I 256 /dev/hda1
+
+  - Mounting:
+
+	# mount -t ext4 /dev/hda1 /wherever
+
+  - When comparing performance with other filesystems, it's always
+    important to try multiple workloads; very often a subtle change in a
+    workload parameter can completely change the ranking of which
+    filesystems do well compared to others.  When comparing versus ext3,
+    note that ext4 enables write barriers by default, while ext3 does
+    not enable write barriers by default.  So it is useful to use
+    explicitly specify whether barriers are enabled or not when via the
+    '-o barriers=[0|1]' mount option for both ext3 and ext4 filesystems
+    for a fair comparison.  When tuning ext3 for best benchmark numbers,
+    it is often worthwhile to try changing the data journaling mode; '-o
+    data=writeback' can be faster for some workloads.  (Note however that
+    running mounted with data=writeback can potentially leave stale data
+    exposed in recently written files in case of an unclean shutdown,
+    which could be a security exposure in some situations.)  Configuring
+    the filesystem with a large journal can also be helpful for
+    metadata-intensive workloads.
+
+Features
+========
+
+Currently Available
+-------------------
+
+* ability to use filesystems > 16TB (e2fsprogs support not available yet)
+* extent format reduces metadata overhead (RAM, IO for access, transactions)
+* extent format more robust in face of on-disk corruption due to magics,
+* internal redundancy in tree
+* improved file allocation (multi-block alloc)
+* lift 32000 subdirectory limit imposed by i_links_count[1]
+* nsec timestamps for mtime, atime, ctime, create time
+* inode version field on disk (NFSv4, Lustre)
+* reduced e2fsck time via uninit_bg feature
+* journal checksumming for robustness, performance
+* persistent file preallocation (e.g for streaming media, databases)
+* ability to pack bitmaps and inode tables into larger virtual groups via the
+  flex_bg feature
+* large file support
+* inode allocation using large virtual block groups via flex_bg
+* delayed allocation
+* large block (up to pagesize) support
+* efficient new ordered mode in JBD2 and ext4 (avoid using buffer head to force
+  the ordering)
+
+[1] Filesystems with a block size of 1k may see a limit imposed by the
+directory hash tree having a maximum depth of two.
+
+Options
+=======
+
+When mounting an ext4 filesystem, the following option are accepted:
+(*) == default
+
+  ro
+        Mount filesystem read only. Note that ext4 will replay the journal (and
+        thus write to the partition) even when mounted "read only". The mount
+        options "ro,noload" can be used to prevent writes to the filesystem.
+
+  journal_checksum
+        Enable checksumming of the journal transactions.  This will allow the
+        recovery code in e2fsck and the kernel to detect corruption in the
+        kernel.  It is a compatible change and will be ignored by older
+        kernels.
+
+  journal_async_commit
+        Commit block can be written to disk without waiting for descriptor
+        blocks. If enabled older kernels cannot mount the device. This will
+        enable 'journal_checksum' internally.
+
+  journal_path=path, journal_dev=devnum
+        When the external journal device's major/minor numbers have changed,
+        these options allow the user to specify the new journal location.  The
+        journal device is identified through either its new major/minor numbers
+        encoded in devnum, or via a path to the device.
+
+  norecovery, noload
+        Don't load the journal on mounting.  Note that if the filesystem was
+        not unmounted cleanly, skipping the journal replay will lead to the
+        filesystem containing inconsistencies that can lead to any number of
+        problems.
+
+  data=journal
+        All data are committed into the journal prior to being written into the
+        main file system.  Enabling this mode will disable delayed allocation
+        and O_DIRECT support.
+
+  data=ordered	(*)
+        All data are forced directly out to the main file system prior to its
+        metadata being committed to the journal.
+
+  data=writeback
+        Data ordering is not preserved, data may be written into the main file
+        system after its metadata has been committed to the journal.
+
+  commit=nrsec	(*)
+        Ext4 can be told to sync all its data and metadata every 'nrsec'
+        seconds. The default value is 5 seconds.  This means that if you lose
+        your power, you will lose as much as the latest 5 seconds of work (your
+        filesystem will not be damaged though, thanks to the journaling).  This
+        default value (or any low value) will hurt performance, but it's good
+        for data-safety.  Setting it to 0 will have the same effect as leaving
+        it at the default (5 seconds).  Setting it to very large values will
+        improve performance.
+
+  barrier=<0|1(*)>, barrier(*), nobarrier
+        This enables/disables the use of write barriers in the jbd code.
+        barrier=0 disables, barrier=1 enables.  This also requires an IO stack
+        which can support barriers, and if jbd gets an error on a barrier
+        write, it will disable again with a warning.  Write barriers enforce
+        proper on-disk ordering of journal commits, making volatile disk write
+        caches safe to use, at some performance penalty.  If your disks are
+        battery-backed in one way or another, disabling barriers may safely
+        improve performance.  The mount options "barrier" and "nobarrier" can
+        also be used to enable or disable barriers, for consistency with other
+        ext4 mount options.
+
+  inode_readahead_blks=n
+        This tuning parameter controls the maximum number of inode table blocks
+        that ext4's inode table readahead algorithm will pre-read into the
+        buffer cache.  The default value is 32 blocks.
+
+  nouser_xattr
+        Disables Extended User Attributes.  See the attr(5) manual page for
+        more information about extended attributes.
+
+  noacl
+        This option disables POSIX Access Control List support. If ACL support
+        is enabled in the kernel configuration (CONFIG_EXT4_FS_POSIX_ACL), ACL
+        is enabled by default on mount. See the acl(5) manual page for more
+        information about acl.
+
+  bsddf	(*)
+        Make 'df' act like BSD.
+
+  minixdf
+        Make 'df' act like Minix.
+
+  debug
+        Extra debugging information is sent to syslog.
+
+  abort
+        Simulate the effects of calling ext4_abort() for debugging purposes.
+        This is normally used while remounting a filesystem which is already
+        mounted.
+
+  errors=remount-ro
+        Remount the filesystem read-only on an error.
+
+  errors=continue
+        Keep going on a filesystem error.
+
+  errors=panic
+        Panic and halt the machine if an error occurs.  (These mount options
+        override the errors behavior specified in the superblock, which can be
+        configured using tune2fs)
+
+  data_err=ignore(*)
+        Just print an error message if an error occurs in a file data buffer in
+        ordered mode.
+  data_err=abort
+        Abort the journal if an error occurs in a file data buffer in ordered
+        mode.
+
+  grpid | bsdgroups
+        New objects have the group ID of their parent.
+
+  nogrpid (*) | sysvgroups
+        New objects have the group ID of their creator.
+
+  resgid=n
+        The group ID which may use the reserved blocks.
+
+  resuid=n
+        The user ID which may use the reserved blocks.
+
+  sb=
+        Use alternate superblock at this location.
+
+  quota, noquota, grpquota, usrquota
+        These options are ignored by the filesystem. They are used only by
+        quota tools to recognize volumes where quota should be turned on. See
+        documentation in the quota-tools package for more details
+        (http://sourceforge.net/projects/linuxquota).
+
+  jqfmt=<quota type>, usrjquota=<file>, grpjquota=<file>
+        These options tell filesystem details about quota so that quota
+        information can be properly updated during journal replay. They replace
+        the above quota options. See documentation in the quota-tools package
+        for more details (http://sourceforge.net/projects/linuxquota).
+
+  stripe=n
+        Number of filesystem blocks that mballoc will try to use for allocation
+        size and alignment. For RAID5/6 systems this should be the number of
+        data disks *  RAID chunk size in file system blocks.
+
+  delalloc	(*)
+        Defer block allocation until just before ext4 writes out the block(s)
+        in question.  This allows ext4 to better allocation decisions more
+        efficiently.
+
+  nodelalloc
+        Disable delayed allocation.  Blocks are allocated when the data is
+        copied from userspace to the page cache, either via the write(2) system
+        call or when an mmap'ed page which was previously unallocated is
+        written for the first time.
+
+  max_batch_time=usec
+        Maximum amount of time ext4 should wait for additional filesystem
+        operations to be batch together with a synchronous write operation.
+        Since a synchronous write operation is going to force a commit and then
+        a wait for the I/O complete, it doesn't cost much, and can be a huge
+        throughput win, we wait for a small amount of time to see if any other
+        transactions can piggyback on the synchronous write.   The algorithm
+        used is designed to automatically tune for the speed of the disk, by
+        measuring the amount of time (on average) that it takes to finish
+        committing a transaction.  Call this time the "commit time".  If the
+        time that the transaction has been running is less than the commit
+        time, ext4 will try sleeping for the commit time to see if other
+        operations will join the transaction.   The commit time is capped by
+        the max_batch_time, which defaults to 15000us (15ms).   This
+        optimization can be turned off entirely by setting max_batch_time to 0.
+
+  min_batch_time=usec
+        This parameter sets the commit time (as described above) to be at least
+        min_batch_time.  It defaults to zero microseconds.  Increasing this
+        parameter may improve the throughput of multi-threaded, synchronous
+        workloads on very fast disks, at the cost of increasing latency.
+
+  journal_ioprio=prio
+        The I/O priority (from 0 to 7, where 0 is the highest priority) which
+        should be used for I/O operations submitted by kjournald2 during a
+        commit operation.  This defaults to 3, which is a slightly higher
+        priority than the default I/O priority.
+
+  auto_da_alloc(*), noauto_da_alloc
+        Many broken applications don't use fsync() when replacing existing
+        files via patterns such as fd = open("foo.new")/write(fd,..)/close(fd)/
+        rename("foo.new", "foo"), or worse yet, fd = open("foo",
+        O_TRUNC)/write(fd,..)/close(fd).  If auto_da_alloc is enabled, ext4
+        will detect the replace-via-rename and replace-via-truncate patterns
+        and force that any delayed allocation blocks are allocated such that at
+        the next journal commit, in the default data=ordered mode, the data
+        blocks of the new file are forced to disk before the rename() operation
+        is committed.  This provides roughly the same level of guarantees as
+        ext3, and avoids the "zero-length" problem that can happen when a
+        system crashes before the delayed allocation blocks are forced to disk.
+
+  noinit_itable
+        Do not initialize any uninitialized inode table blocks in the
+        background.  This feature may be used by installation CD's so that the
+        install process can complete as quickly as possible; the inode table
+        initialization process would then be deferred until the next time the
+        file system is unmounted.
+
+  init_itable=n
+        The lazy itable init code will wait n times the number of milliseconds
+        it took to zero out the previous block group's inode table.  This
+        minimizes the impact on the system performance while file system's
+        inode table is being initialized.
+
+  discard, nodiscard(*)
+        Controls whether ext4 should issue discard/TRIM commands to the
+        underlying block device when blocks are freed.  This is useful for SSD
+        devices and sparse/thinly-provisioned LUNs, but it is off by default
+        until sufficient testing has been done.
+
+  nouid32
+        Disables 32-bit UIDs and GIDs.  This is for interoperability  with
+        older kernels which only store and expect 16-bit values.
+
+  block_validity(*), noblock_validity
+        These options enable or disable the in-kernel facility for tracking
+        filesystem metadata blocks within internal data structures.  This
+        allows multi- block allocator and other routines to notice bugs or
+        corrupted allocation bitmaps which cause blocks to be allocated which
+        overlap with filesystem metadata blocks.
+
+  dioread_lock, dioread_nolock
+        Controls whether or not ext4 should use the DIO read locking. If the
+        dioread_nolock option is specified ext4 will allocate uninitialized
+        extent before buffer write and convert the extent to initialized after
+        IO completes. This approach allows ext4 code to avoid using inode
+        mutex, which improves scalability on high speed storages. However this
+        does not work with data journaling and dioread_nolock option will be
+        ignored with kernel warning. Note that dioread_nolock code path is only
+        used for extent-based files.  Because of the restrictions this options
+        comprises it is off by default (e.g. dioread_lock).
+
+  max_dir_size_kb=n
+        This limits the size of directories so that any attempt to expand them
+        beyond the specified limit in kilobytes will cause an ENOSPC error.
+        This is useful in memory constrained environments, where a very large
+        directory can cause severe performance problems or even provoke the Out
+        Of Memory killer.  (For example, if there is only 512mb memory
+        available, a 176mb directory may seriously cramp the system's style.)
+
+  i_version
+        Enable 64-bit inode version support. This option is off by default.
+
+  dax
+        Use direct access (no page cache).  See
+        Documentation/filesystems/dax.txt.  Note that this option is
+        incompatible with data=journal.
+
+Data Mode
+=========
+There are 3 different data modes:
+
+* writeback mode
+
+  In data=writeback mode, ext4 does not journal data at all.  This mode provides
+  a similar level of journaling as that of XFS, JFS, and ReiserFS in its default
+  mode - metadata journaling.  A crash+recovery can cause incorrect data to
+  appear in files which were written shortly before the crash.  This mode will
+  typically provide the best ext4 performance.
+
+* ordered mode
+
+  In data=ordered mode, ext4 only officially journals metadata, but it logically
+  groups metadata information related to data changes with the data blocks into
+  a single unit called a transaction.  When it's time to write the new metadata
+  out to disk, the associated data blocks are written first.  In general, this
+  mode performs slightly slower than writeback but significantly faster than
+  journal mode.
+
+* journal mode
+
+  data=journal mode provides full data and metadata journaling.  All new data is
+  written to the journal first, and then to its final location.  In the event of
+  a crash, the journal can be replayed, bringing both data and metadata into a
+  consistent state.  This mode is the slowest except when data needs to be read
+  from and written to disk at the same time where it outperforms all others
+  modes.  Enabling this mode will disable delayed allocation and O_DIRECT
+  support.
+
+/proc entries
+=============
+
+Information about mounted ext4 file systems can be found in
+/proc/fs/ext4.  Each mounted filesystem will have a directory in
+/proc/fs/ext4 based on its device name (i.e., /proc/fs/ext4/hdc or
+/proc/fs/ext4/dm-0).   The files in each per-device directory are shown
+in table below.
+
+Files in /proc/fs/ext4/<devname>
+
+  mb_groups
+        details of multiblock allocator buddy cache of free blocks
+
+/sys entries
+============
+
+Information about mounted ext4 file systems can be found in
+/sys/fs/ext4.  Each mounted filesystem will have a directory in
+/sys/fs/ext4 based on its device name (i.e., /sys/fs/ext4/hdc or
+/sys/fs/ext4/dm-0).   The files in each per-device directory are shown
+in table below.
+
+Files in /sys/fs/ext4/<devname>:
+
+(see also Documentation/ABI/testing/sysfs-fs-ext4)
+
+  delayed_allocation_blocks
+        This file is read-only and shows the number of blocks that are dirty in
+        the page cache, but which do not have their location in the filesystem
+        allocated yet.
+
+  inode_goal
+        Tuning parameter which (if non-zero) controls the goal inode used by
+        the inode allocator in preference to all other allocation heuristics.
+        This is intended for debugging use only, and should be 0 on production
+        systems.
+
+  inode_readahead_blks
+        Tuning parameter which controls the maximum number of inode table
+        blocks that ext4's inode table readahead algorithm will pre-read into
+        the buffer cache.
+
+  lifetime_write_kbytes
+        This file is read-only and shows the number of kilobytes of data that
+        have been written to this filesystem since it was created.
+
+  max_writeback_mb_bump
+        The maximum number of megabytes the writeback code will try to write
+        out before move on to another inode.
+
+  mb_group_prealloc
+        The multiblock allocator will round up allocation requests to a
+        multiple of this tuning parameter if the stripe size is not set in the
+        ext4 superblock
+
+  mb_max_to_scan
+        The maximum number of extents the multiblock allocator will search to
+        find the best extent.
+
+  mb_min_to_scan
+        The minimum number of extents the multiblock allocator will search to
+        find the best extent.
+
+  mb_order2_req
+        Tuning parameter which controls the minimum size for requests (as a
+        power of 2) where the buddy cache is used.
+
+  mb_stats
+        Controls whether the multiblock allocator should collect statistics,
+        which are shown during the unmount. 1 means to collect statistics, 0
+        means not to collect statistics.
+
+  mb_stream_req
+        Files which have fewer blocks than this tunable parameter will have
+        their blocks allocated out of a block group specific preallocation
+        pool, so that small files are packed closely together.  Each large file
+        will have its blocks allocated out of its own unique preallocation
+        pool.
+
+  session_write_kbytes
+        This file is read-only and shows the number of kilobytes of data that
+        have been written to this filesystem since it was mounted.
+
+  reserved_clusters
+        This is RW file and contains number of reserved clusters in the file
+        system which will be used in the specific situations to avoid costly
+        zeroout, unexpected ENOSPC, or possible data loss. The default is 2% or
+        4096 clusters, whichever is smaller and this can be changed however it
+        can never exceed number of clusters in the file system. If there is not
+        enough space for the reserved space when mounting the file mount will
+        _not_ fail.
+
+Ioctls
+======
+
+There is some Ext4 specific functionality which can be accessed by applications
+through the system call interfaces. The list of all Ext4 specific ioctls are
+shown in the table below.
+
+Table of Ext4 specific ioctls
+
+  EXT4_IOC_GETFLAGS
+        Get additional attributes associated with inode.  The ioctl argument is
+        an integer bitfield, with bit values described in ext4.h. This ioctl is
+        an alias for FS_IOC_GETFLAGS.
+
+  EXT4_IOC_SETFLAGS
+        Set additional attributes associated with inode.  The ioctl argument is
+        an integer bitfield, with bit values described in ext4.h. This ioctl is
+        an alias for FS_IOC_SETFLAGS.
+
+  EXT4_IOC_GETVERSION, EXT4_IOC_GETVERSION_OLD
+        Get the inode i_generation number stored for each inode. The
+        i_generation number is normally changed only when new inode is created
+        and it is particularly useful for network filesystems. The '_OLD'
+        version of this ioctl is an alias for FS_IOC_GETVERSION.
+
+  EXT4_IOC_SETVERSION, EXT4_IOC_SETVERSION_OLD
+        Set the inode i_generation number stored for each inode. The '_OLD'
+        version of this ioctl is an alias for FS_IOC_SETVERSION.
+
+  EXT4_IOC_GROUP_EXTEND
+        This ioctl has the same purpose as the resize mount option. It allows
+        to resize filesystem to the end of the last existing block group,
+        further resize has to be done with resize2fs, either online, or
+        offline. The argument points to the unsigned logn number representing
+        the filesystem new block count.
+
+  EXT4_IOC_MOVE_EXT
+        Move the block extents from orig_fd (the one this ioctl is pointing to)
+        to the donor_fd (the one specified in move_extent structure passed as
+        an argument to this ioctl). Then, exchange inode metadata between
+        orig_fd and donor_fd.  This is especially useful for online
+        defragmentation, because the allocator has the opportunity to allocate
+        moved blocks better, ideally into one contiguous extent.
+
+  EXT4_IOC_GROUP_ADD
+        Add a new group descriptor to an existing or new group descriptor
+        block. The new group descriptor is described by ext4_new_group_input
+        structure, which is passed as an argument to this ioctl. This is
+        especially useful in conjunction with EXT4_IOC_GROUP_EXTEND, which
+        allows online resize of the filesystem to the end of the last existing
+        block group.  Those two ioctls combined is used in userspace online
+        resize tool (e.g. resize2fs).
+
+  EXT4_IOC_MIGRATE
+        This ioctl operates on the filesystem itself.  It converts (migrates)
+        ext3 indirect block mapped inode to ext4 extent mapped inode by walking
+        through indirect block mapping of the original inode and converting
+        contiguous block ranges into ext4 extents of the temporary inode. Then,
+        inodes are swapped. This ioctl might help, when migrating from ext3 to
+        ext4 filesystem, however suggestion is to create fresh ext4 filesystem
+        and copy data from the backup. Note, that filesystem has to support
+        extents for this ioctl to work.
+
+  EXT4_IOC_ALLOC_DA_BLKS
+        Force all of the delay allocated blocks to be allocated to preserve
+        application-expected ext3 behaviour. Note that this will also start
+        triggering a write of the data blocks, but this behaviour may change in
+        the future as it is not necessary and has been done this way only for
+        sake of simplicity.
+
+  EXT4_IOC_RESIZE_FS
+        Resize the filesystem to a new size.  The number of blocks of resized
+        filesystem is passed in via 64 bit integer argument.  The kernel
+        allocates bitmaps and inode table, the userspace tool thus just passes
+        the new number of blocks.
+
+  EXT4_IOC_SWAP_BOOT
+        Swap i_blocks and associated attributes (like i_blocks, i_size,
+        i_flags, ...) from the specified inode with inode EXT4_BOOT_LOADER_INO
+        (#5). This is typically used to store a boot loader in a secure part of
+        the filesystem, where it can't be changed by a normal user by accident.
+        The data blocks of the previous boot loader will be associated with the
+        given inode.
+
+References
+==========
+
+kernel source:	<file:fs/ext4/>
+		<file:fs/jbd2/>
+
+programs:	http://e2fsprogs.sourceforge.net/
+
+useful links:	http://fedoraproject.org/wiki/ext3-devel
+		http://www.bullopensource.org/ext4/
+		http://ext4.wiki.kernel.org/index.php/Main_Page
+		http://fedoraproject.org/wiki/Features/Ext4
diff --git a/Documentation/admin-guide/index.rst b/Documentation/admin-guide/index.rst
index 0873685bab0f..965745d5fb9a 100644
--- a/Documentation/admin-guide/index.rst
+++ b/Documentation/admin-guide/index.rst
@@ -71,6 +71,7 @@ configure specific aspects of kernel behavior to your liking.
    java
    ras
    bcache
+   ext4
    pm/index
    thunderbolt
    LSM/index
diff --git a/Documentation/conf.py b/Documentation/conf.py
index b691af4831fa..ede67ccafc29 100644
--- a/Documentation/conf.py
+++ b/Documentation/conf.py
@@ -383,6 +383,10 @@ latex_documents = [
      'The kernel development community', 'manual'),
     ('filesystems/index', 'filesystems.tex', 'Linux Filesystems API',
      'The kernel development community', 'manual'),
+    ('admin-guide/ext4', 'ext4-admin-guide.tex', 'ext4 Administration Guide',
+     'ext4 Community', 'manual'),
+    ('filesystems/ext4/index', 'ext4-data-structures.tex',
+     'ext4 Data Structures and Algorithms', 'ext4 Community', 'manual'),
     ('gpu/index', 'gpu.tex', 'Linux GPU Driver Developer\'s Guide',
      'The kernel development community', 'manual'),
     ('input/index', 'linux-input.tex', 'The Linux input driver subsystem',
diff --git a/Documentation/filesystems/ext4/ondisk/about.rst b/Documentation/filesystems/ext4/about.rst
index 0aadba052264..0aadba052264 100644
--- a/Documentation/filesystems/ext4/ondisk/about.rst
+++ b/Documentation/filesystems/ext4/about.rst
diff --git a/Documentation/filesystems/ext4/ondisk/allocators.rst b/Documentation/filesystems/ext4/allocators.rst
index 7aa85152ace3..7aa85152ace3 100644
--- a/Documentation/filesystems/ext4/ondisk/allocators.rst
+++ b/Documentation/filesystems/ext4/allocators.rst
diff --git a/Documentation/filesystems/ext4/ondisk/attributes.rst b/Documentation/filesystems/ext4/attributes.rst
index 0b01b67b81fe..54386a010a8d 100644
--- a/Documentation/filesystems/ext4/ondisk/attributes.rst
+++ b/Documentation/filesystems/ext4/attributes.rst
@@ -30,7 +30,7 @@ Extended attributes, when stored after the inode, have a header
 ``ext4_xattr_ibody_header`` that is 4 bytes long:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -47,7 +47,7 @@ The beginning of an extended attribute block is in
 ``struct ext4_xattr_header``, which is 32 bytes long:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -92,7 +92,7 @@ entries must be stored in sorted order. The sort order is
 Attributes stored inside an inode do not need be stored in sorted order.
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -157,7 +157,7 @@ attribute name index field is set, and matching string is removed from
 the key name. Here is a map of name index values to key prefixes:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 16 64
    :header-rows: 1
 
    * - Name Index
diff --git a/Documentation/filesystems/ext4/ondisk/bigalloc.rst b/Documentation/filesystems/ext4/bigalloc.rst
index c6d88557553c..c6d88557553c 100644
--- a/Documentation/filesystems/ext4/ondisk/bigalloc.rst
+++ b/Documentation/filesystems/ext4/bigalloc.rst
diff --git a/Documentation/filesystems/ext4/ondisk/bitmaps.rst b/Documentation/filesystems/ext4/bitmaps.rst
index c7546dbc197a..c7546dbc197a 100644
--- a/Documentation/filesystems/ext4/ondisk/bitmaps.rst
+++ b/Documentation/filesystems/ext4/bitmaps.rst
diff --git a/Documentation/filesystems/ext4/ondisk/blockgroup.rst b/Documentation/filesystems/ext4/blockgroup.rst
index baf888e4c06a..baf888e4c06a 100644
--- a/Documentation/filesystems/ext4/ondisk/blockgroup.rst
+++ b/Documentation/filesystems/ext4/blockgroup.rst
diff --git a/Documentation/filesystems/ext4/ondisk/blockmap.rst b/Documentation/filesystems/ext4/blockmap.rst
index 30e25750d88a..30e25750d88a 100644
--- a/Documentation/filesystems/ext4/ondisk/blockmap.rst
+++ b/Documentation/filesystems/ext4/blockmap.rst
diff --git a/Documentation/filesystems/ext4/ondisk/blocks.rst b/Documentation/filesystems/ext4/blocks.rst
index 73d4dc0f7bda..73d4dc0f7bda 100644
--- a/Documentation/filesystems/ext4/ondisk/blocks.rst
+++ b/Documentation/filesystems/ext4/blocks.rst
diff --git a/Documentation/filesystems/ext4/ondisk/checksums.rst b/Documentation/filesystems/ext4/checksums.rst
index 9d6a793b2e03..5519e253810d 100644
--- a/Documentation/filesystems/ext4/ondisk/checksums.rst
+++ b/Documentation/filesystems/ext4/checksums.rst
@@ -28,7 +28,7 @@ of checksum. The checksum function is whatever the superblock describes
 (crc32c as of October 2013) unless noted otherwise.
 
 .. list-table::
-   :widths: 1 1 4
+   :widths: 20 8 50
    :header-rows: 1
 
    * - Metadata
diff --git a/Documentation/filesystems/ext4/ondisk/directory.rst b/Documentation/filesystems/ext4/directory.rst
index 8fcba68c2884..614034e24669 100644
--- a/Documentation/filesystems/ext4/ondisk/directory.rst
+++ b/Documentation/filesystems/ext4/directory.rst
@@ -34,7 +34,7 @@ is at most 263 bytes long, though on disk you'll need to reference
 ``dirent.rec_len`` to know for sure.
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -66,7 +66,7 @@ tree traversal. This format is ``ext4_dir_entry_2``, which is at most
 ``dirent.rec_len`` to know for sure.
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -99,7 +99,7 @@ tree traversal. This format is ``ext4_dir_entry_2``, which is at most
 The directory file type is one of the following values:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 16 64
    :header-rows: 1
 
    * - Value
@@ -130,7 +130,7 @@ in the place where the name normally goes. The structure is
 ``struct ext4_dir_entry_tail``:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -212,7 +212,7 @@ The root of the htree is in ``struct dx_root``, which is the full length
 of a data block:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -305,7 +305,7 @@ of a data block:
 The directory hash is one of the following values:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 16 64
    :header-rows: 1
 
    * - Value
@@ -327,7 +327,7 @@ Interior nodes of an htree are recorded as ``struct dx_node``, which is
 also the full length of a data block:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -375,7 +375,7 @@ The hash maps that exist in both ``struct dx_root`` and
 long:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -405,7 +405,7 @@ directory index (which will ensure that there's space for the checksum.
 The dx\_tail structure is 8 bytes long and looks like this:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
diff --git a/Documentation/filesystems/ext4/ondisk/dynamic.rst b/Documentation/filesystems/ext4/dynamic.rst
index bb0c84333341..bb0c84333341 100644
--- a/Documentation/filesystems/ext4/ondisk/dynamic.rst
+++ b/Documentation/filesystems/ext4/dynamic.rst
diff --git a/Documentation/filesystems/ext4/ondisk/eainode.rst b/Documentation/filesystems/ext4/eainode.rst
index ecc0d01a0a72..ecc0d01a0a72 100644
--- a/Documentation/filesystems/ext4/ondisk/eainode.rst
+++ b/Documentation/filesystems/ext4/eainode.rst
diff --git a/Documentation/filesystems/ext4/ext4.rst b/Documentation/filesystems/ext4/ext4.rst
deleted file mode 100644
index 9d4368d591fa..000000000000
--- a/Documentation/filesystems/ext4/ext4.rst
+++ /dev/null
@@ -1,613 +0,0 @@
-.. SPDX-License-Identifier: GPL-2.0
-
-========================
-General Information
-========================
-
-Ext4 is an advanced level of the ext3 filesystem which incorporates
-scalability and reliability enhancements for supporting large filesystems
-(64 bit) in keeping with increasing disk capacities and state-of-the-art
-feature requirements.
-
-Mailing list:	linux-ext4@vger.kernel.org
-Web site:	http://ext4.wiki.kernel.org
-
-
-Quick usage instructions
-========================
-
-Note: More extensive information for getting started with ext4 can be
-found at the ext4 wiki site at the URL:
-http://ext4.wiki.kernel.org/index.php/Ext4_Howto
-
-  - The latest version of e2fsprogs can be found at:
-
-    https://www.kernel.org/pub/linux/kernel/people/tytso/e2fsprogs/
-
-	or
-
-    http://sourceforge.net/project/showfiles.php?group_id=2406
-
-	or grab the latest git repository from:
-
-   https://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git
-
-  - Create a new filesystem using the ext4 filesystem type:
-
-        # mke2fs -t ext4 /dev/hda1
-
-    Or to configure an existing ext3 filesystem to support extents:
-
-	# tune2fs -O extents /dev/hda1
-
-    If the filesystem was created with 128 byte inodes, it can be
-    converted to use 256 byte for greater efficiency via:
-
-        # tune2fs -I 256 /dev/hda1
-
-  - Mounting:
-
-	# mount -t ext4 /dev/hda1 /wherever
-
-  - When comparing performance with other filesystems, it's always
-    important to try multiple workloads; very often a subtle change in a
-    workload parameter can completely change the ranking of which
-    filesystems do well compared to others.  When comparing versus ext3,
-    note that ext4 enables write barriers by default, while ext3 does
-    not enable write barriers by default.  So it is useful to use
-    explicitly specify whether barriers are enabled or not when via the
-    '-o barriers=[0|1]' mount option for both ext3 and ext4 filesystems
-    for a fair comparison.  When tuning ext3 for best benchmark numbers,
-    it is often worthwhile to try changing the data journaling mode; '-o
-    data=writeback' can be faster for some workloads.  (Note however that
-    running mounted with data=writeback can potentially leave stale data
-    exposed in recently written files in case of an unclean shutdown,
-    which could be a security exposure in some situations.)  Configuring
-    the filesystem with a large journal can also be helpful for
-    metadata-intensive workloads.
-
-Features
-========
-
-Currently Available
--------------------
-
-* ability to use filesystems > 16TB (e2fsprogs support not available yet)
-* extent format reduces metadata overhead (RAM, IO for access, transactions)
-* extent format more robust in face of on-disk corruption due to magics,
-* internal redundancy in tree
-* improved file allocation (multi-block alloc)
-* lift 32000 subdirectory limit imposed by i_links_count[1]
-* nsec timestamps for mtime, atime, ctime, create time
-* inode version field on disk (NFSv4, Lustre)
-* reduced e2fsck time via uninit_bg feature
-* journal checksumming for robustness, performance
-* persistent file preallocation (e.g for streaming media, databases)
-* ability to pack bitmaps and inode tables into larger virtual groups via the
-  flex_bg feature
-* large file support
-* inode allocation using large virtual block groups via flex_bg
-* delayed allocation
-* large block (up to pagesize) support
-* efficient new ordered mode in JBD2 and ext4 (avoid using buffer head to force
-  the ordering)
-
-[1] Filesystems with a block size of 1k may see a limit imposed by the
-directory hash tree having a maximum depth of two.
-
-Options
-=======
-
-When mounting an ext4 filesystem, the following option are accepted:
-(*) == default
-
-======================= =======================================================
-Mount Option            Description
-======================= =======================================================
-ro                   	Mount filesystem read only. Note that ext4 will
-                     	replay the journal (and thus write to the
-                     	partition) even when mounted "read only". The
-                     	mount options "ro,noload" can be used to prevent
-		     	writes to the filesystem.
-
-journal_checksum	Enable checksumming of the journal transactions.
-			This will allow the recovery code in e2fsck and the
-			kernel to detect corruption in the kernel.  It is a
-			compatible change and will be ignored by older kernels.
-
-journal_async_commit	Commit block can be written to disk without waiting
-			for descriptor blocks. If enabled older kernels cannot
-			mount the device. This will enable 'journal_checksum'
-			internally.
-
-journal_path=path
-journal_dev=devnum	When the external journal device's major/minor numbers
-			have changed, these options allow the user to specify
-			the new journal location.  The journal device is
-			identified through either its new major/minor numbers
-			encoded in devnum, or via a path to the device.
-
-norecovery		Don't load the journal on mounting.  Note that
-noload			if the filesystem was not unmounted cleanly,
-                     	skipping the journal replay will lead to the
-                     	filesystem containing inconsistencies that can
-                     	lead to any number of problems.
-
-data=journal		All data are committed into the journal prior to being
-			written into the main file system.  Enabling
-			this mode will disable delayed allocation and
-			O_DIRECT support.
-
-data=ordered	(*)	All data are forced directly out to the main file
-			system prior to its metadata being committed to the
-			journal.
-
-data=writeback		Data ordering is not preserved, data may be written
-			into the main file system after its metadata has been
-			committed to the journal.
-
-commit=nrsec	(*)	Ext4 can be told to sync all its data and metadata
-			every 'nrsec' seconds. The default value is 5 seconds.
-			This means that if you lose your power, you will lose
-			as much as the latest 5 seconds of work (your
-			filesystem will not be damaged though, thanks to the
-			journaling).  This default value (or any low value)
-			will hurt performance, but it's good for data-safety.
-			Setting it to 0 will have the same effect as leaving
-			it at the default (5 seconds).
-			Setting it to very large values will improve
-			performance.
-
-barrier=<0|1(*)>	This enables/disables the use of write barriers in
-barrier(*)		the jbd code.  barrier=0 disables, barrier=1 enables.
-nobarrier		This also requires an IO stack which can support
-			barriers, and if jbd gets an error on a barrier
-			write, it will disable again with a warning.
-			Write barriers enforce proper on-disk ordering
-			of journal commits, making volatile disk write caches
-			safe to use, at some performance penalty.  If
-			your disks are battery-backed in one way or another,
-			disabling barriers may safely improve performance.
-			The mount options "barrier" and "nobarrier" can
-			also be used to enable or disable barriers, for
-			consistency with other ext4 mount options.
-
-inode_readahead_blks=n	This tuning parameter controls the maximum
-			number of inode table blocks that ext4's inode
-			table readahead algorithm will pre-read into
-			the buffer cache.  The default value is 32 blocks.
-
-nouser_xattr		Disables Extended User Attributes.  See the
-			attr(5) manual page for more information about
-			extended attributes.
-
-noacl			This option disables POSIX Access Control List
-			support. If ACL support is enabled in the kernel
-			configuration (CONFIG_EXT4_FS_POSIX_ACL), ACL is
-			enabled by default on mount. See the acl(5) manual
-			page for more information about acl.
-
-bsddf		(*)	Make 'df' act like BSD.
-minixdf			Make 'df' act like Minix.
-
-debug			Extra debugging information is sent to syslog.
-
-abort			Simulate the effects of calling ext4_abort() for
-			debugging purposes.  This is normally used while
-			remounting a filesystem which is already mounted.
-
-errors=remount-ro	Remount the filesystem read-only on an error.
-errors=continue		Keep going on a filesystem error.
-errors=panic		Panic and halt the machine if an error occurs.
-                        (These mount options override the errors behavior
-                        specified in the superblock, which can be configured
-                        using tune2fs)
-
-data_err=ignore(*)	Just print an error message if an error occurs
-			in a file data buffer in ordered mode.
-data_err=abort		Abort the journal if an error occurs in a file
-			data buffer in ordered mode.
-
-grpid			New objects have the group ID of their parent.
-bsdgroups
-
-nogrpid		(*)	New objects have the group ID of their creator.
-sysvgroups
-
-resgid=n		The group ID which may use the reserved blocks.
-
-resuid=n		The user ID which may use the reserved blocks.
-
-sb=n			Use alternate superblock at this location.
-
-quota			These options are ignored by the filesystem. They
-noquota			are used only by quota tools to recognize volumes
-grpquota		where quota should be turned on. See documentation
-usrquota		in the quota-tools package for more details
-			(http://sourceforge.net/projects/linuxquota).
-
-jqfmt=<quota type>	These options tell filesystem details about quota
-usrjquota=<file>	so that quota information can be properly updated
-grpjquota=<file>	during journal replay. They replace the above
-			quota options. See documentation in the quota-tools
-			package for more details
-			(http://sourceforge.net/projects/linuxquota).
-
-stripe=n		Number of filesystem blocks that mballoc will try
-			to use for allocation size and alignment. For RAID5/6
-			systems this should be the number of data
-			disks *  RAID chunk size in file system blocks.
-
-delalloc	(*)	Defer block allocation until just before ext4
-			writes out the block(s) in question.  This
-			allows ext4 to better allocation decisions
-			more efficiently.
-nodelalloc		Disable delayed allocation.  Blocks are allocated
-			when the data is copied from userspace to the
-			page cache, either via the write(2) system call
-			or when an mmap'ed page which was previously
-			unallocated is written for the first time.
-
-max_batch_time=usec	Maximum amount of time ext4 should wait for
-			additional filesystem operations to be batch
-			together with a synchronous write operation.
-			Since a synchronous write operation is going to
-			force a commit and then a wait for the I/O
-			complete, it doesn't cost much, and can be a
-			huge throughput win, we wait for a small amount
-			of time to see if any other transactions can
-			piggyback on the synchronous write.   The
-			algorithm used is designed to automatically tune
-			for the speed of the disk, by measuring the
-			amount of time (on average) that it takes to
-			finish committing a transaction.  Call this time
-			the "commit time".  If the time that the
-			transaction has been running is less than the
-			commit time, ext4 will try sleeping for the
-			commit time to see if other operations will join
-			the transaction.   The commit time is capped by
-			the max_batch_time, which defaults to 15000us
-			(15ms).   This optimization can be turned off
-			entirely by setting max_batch_time to 0.
-
-min_batch_time=usec	This parameter sets the commit time (as
-			described above) to be at least min_batch_time.
-			It defaults to zero microseconds.  Increasing
-			this parameter may improve the throughput of
-			multi-threaded, synchronous workloads on very
-			fast disks, at the cost of increasing latency.
-
-journal_ioprio=prio	The I/O priority (from 0 to 7, where 0 is the
-			highest priority) which should be used for I/O
-			operations submitted by kjournald2 during a
-			commit operation.  This defaults to 3, which is
-			a slightly higher priority than the default I/O
-			priority.
-
-auto_da_alloc(*)	Many broken applications don't use fsync() when 
-noauto_da_alloc		replacing existing files via patterns such as
-			fd = open("foo.new")/write(fd,..)/close(fd)/
-			rename("foo.new", "foo"), or worse yet,
-			fd = open("foo", O_TRUNC)/write(fd,..)/close(fd).
-			If auto_da_alloc is enabled, ext4 will detect
-			the replace-via-rename and replace-via-truncate
-			patterns and force that any delayed allocation
-			blocks are allocated such that at the next
-			journal commit, in the default data=ordered
-			mode, the data blocks of the new file are forced
-			to disk before the rename() operation is
-			committed.  This provides roughly the same level
-			of guarantees as ext3, and avoids the
-			"zero-length" problem that can happen when a
-			system crashes before the delayed allocation
-			blocks are forced to disk.
-
-noinit_itable		Do not initialize any uninitialized inode table
-			blocks in the background.  This feature may be
-			used by installation CD's so that the install
-			process can complete as quickly as possible; the
-			inode table initialization process would then be
-			deferred until the next time the  file system
-			is unmounted.
-
-init_itable=n		The lazy itable init code will wait n times the
-			number of milliseconds it took to zero out the
-			previous block group's inode table.  This
-			minimizes the impact on the system performance
-			while file system's inode table is being initialized.
-
-discard			Controls whether ext4 should issue discard/TRIM
-nodiscard(*)		commands to the underlying block device when
-			blocks are freed.  This is useful for SSD devices
-			and sparse/thinly-provisioned LUNs, but it is off
-			by default until sufficient testing has been done.
-
-nouid32			Disables 32-bit UIDs and GIDs.  This is for
-			interoperability  with  older kernels which only
-			store and expect 16-bit values.
-
-block_validity(*)	These options enable or disable the in-kernel
-noblock_validity	facility for tracking filesystem metadata blocks
-			within internal data structures.  This allows multi-
-			block allocator and other routines to notice
-			bugs or corrupted allocation bitmaps which cause
-			blocks to be allocated which overlap with
-			filesystem metadata blocks.
-
-dioread_lock		Controls whether or not ext4 should use the DIO read
-dioread_nolock		locking. If the dioread_nolock option is specified
-			ext4 will allocate uninitialized extent before buffer
-			write and convert the extent to initialized after IO
-			completes. This approach allows ext4 code to avoid
-			using inode mutex, which improves scalability on high
-			speed storages. However this does not work with
-			data journaling and dioread_nolock option will be
-			ignored with kernel warning. Note that dioread_nolock
-			code path is only used for extent-based files.
-			Because of the restrictions this options comprises
-			it is off by default (e.g. dioread_lock).
-
-max_dir_size_kb=n	This limits the size of directories so that any
-			attempt to expand them beyond the specified
-			limit in kilobytes will cause an ENOSPC error.
-			This is useful in memory constrained
-			environments, where a very large directory can
-			cause severe performance problems or even
-			provoke the Out Of Memory killer.  (For example,
-			if there is only 512mb memory available, a 176mb
-			directory may seriously cramp the system's style.)
-
-i_version		Enable 64-bit inode version support. This option is
-			off by default.
-
-dax			Use direct access (no page cache).  See
-			Documentation/filesystems/dax.txt.  Note that
-			this option is incompatible with data=journal.
-======================= =======================================================
-
-Data Mode
-=========
-There are 3 different data modes:
-
-* writeback mode
-
-  In data=writeback mode, ext4 does not journal data at all.  This mode provides
-  a similar level of journaling as that of XFS, JFS, and ReiserFS in its default
-  mode - metadata journaling.  A crash+recovery can cause incorrect data to
-  appear in files which were written shortly before the crash.  This mode will
-  typically provide the best ext4 performance.
-
-* ordered mode
-
-  In data=ordered mode, ext4 only officially journals metadata, but it logically
-  groups metadata information related to data changes with the data blocks into
-  a single unit called a transaction.  When it's time to write the new metadata
-  out to disk, the associated data blocks are written first.  In general, this
-  mode performs slightly slower than writeback but significantly faster than
-  journal mode.
-
-* journal mode
-
-  data=journal mode provides full data and metadata journaling.  All new data is
-  written to the journal first, and then to its final location.  In the event of
-  a crash, the journal can be replayed, bringing both data and metadata into a
-  consistent state.  This mode is the slowest except when data needs to be read
-  from and written to disk at the same time where it outperforms all others
-  modes.  Enabling this mode will disable delayed allocation and O_DIRECT
-  support.
-
-/proc entries
-=============
-
-Information about mounted ext4 file systems can be found in
-/proc/fs/ext4.  Each mounted filesystem will have a directory in
-/proc/fs/ext4 based on its device name (i.e., /proc/fs/ext4/hdc or
-/proc/fs/ext4/dm-0).   The files in each per-device directory are shown
-in table below.
-
-Files in /proc/fs/ext4/<devname>
-
-================ =======
- File            Content
-================ =======
- mb_groups       details of multiblock allocator buddy cache of free blocks
-================ =======
-
-/sys entries
-============
-
-Information about mounted ext4 file systems can be found in
-/sys/fs/ext4.  Each mounted filesystem will have a directory in
-/sys/fs/ext4 based on its device name (i.e., /sys/fs/ext4/hdc or
-/sys/fs/ext4/dm-0).   The files in each per-device directory are shown
-in table below.
-
-Files in /sys/fs/ext4/<devname>:
-
-(see also Documentation/ABI/testing/sysfs-fs-ext4)
-
-============================= =================================================
-File                          Content
-============================= =================================================
- delayed_allocation_blocks    This file is read-only and shows the number of
-                              blocks that are dirty in the page cache, but
-                              which do not have their location in the
-                              filesystem allocated yet.
-
-inode_goal                    Tuning parameter which (if non-zero) controls
-                              the goal inode used by the inode allocator in
-                              preference to all other allocation heuristics.
-                              This is intended for debugging use only, and
-                              should be 0 on production systems.
-
-inode_readahead_blks          Tuning parameter which controls the maximum
-                              number of inode table blocks that ext4's inode
-                              table readahead algorithm will pre-read into
-                              the buffer cache
-
-lifetime_write_kbytes         This file is read-only and shows the number of
-                              kilobytes of data that have been written to this
-                              filesystem since it was created.
-
- max_writeback_mb_bump        The maximum number of megabytes the writeback
-                              code will try to write out before move on to
-                              another inode.
-
- mb_group_prealloc            The multiblock allocator will round up allocation
-                              requests to a multiple of this tuning parameter if
-                              the stripe size is not set in the ext4 superblock
-
- mb_max_to_scan               The maximum number of extents the multiblock
-                              allocator will search to find the best extent
-
- mb_min_to_scan               The minimum number of extents the multiblock
-                              allocator will search to find the best extent
-
- mb_order2_req                Tuning parameter which controls the minimum size
-                              for requests (as a power of 2) where the buddy
-                              cache is used
-
- mb_stats                     Controls whether the multiblock allocator should
-                              collect statistics, which are shown during the
-                              unmount. 1 means to collect statistics, 0 means
-                              not to collect statistics
-
- mb_stream_req                Files which have fewer blocks than this tunable
-                              parameter will have their blocks allocated out
-                              of a block group specific preallocation pool, so
-                              that small files are packed closely together.
-                              Each large file will have its blocks allocated
-                              out of its own unique preallocation pool.
-
- session_write_kbytes         This file is read-only and shows the number of
-                              kilobytes of data that have been written to this
-                              filesystem since it was mounted.
-
- reserved_clusters            This is RW file and contains number of reserved
-                              clusters in the file system which will be used
-                              in the specific situations to avoid costly
-                              zeroout, unexpected ENOSPC, or possible data
-                              loss. The default is 2% or 4096 clusters,
-                              whichever is smaller and this can be changed
-                              however it can never exceed number of clusters
-                              in the file system. If there is not enough space
-                              for the reserved space when mounting the file
-                              mount will _not_ fail.
-============================= =================================================
-
-Ioctls
-======
-
-There is some Ext4 specific functionality which can be accessed by applications
-through the system call interfaces. The list of all Ext4 specific ioctls are
-shown in the table below.
-
-Table of Ext4 specific ioctls
-
-============================= =================================================
-Ioctl			      Description
-============================= =================================================
- EXT4_IOC_GETFLAGS	      Get additional attributes associated with inode.
-			      The ioctl argument is an integer bitfield, with
-			      bit values described in ext4.h. This ioctl is an
-			      alias for FS_IOC_GETFLAGS.
-
- EXT4_IOC_SETFLAGS	      Set additional attributes associated with inode.
-			      The ioctl argument is an integer bitfield, with
-			      bit values described in ext4.h. This ioctl is an
-			      alias for FS_IOC_SETFLAGS.
-
- EXT4_IOC_GETVERSION
- EXT4_IOC_GETVERSION_OLD
-			      Get the inode i_generation number stored for
-			      each inode. The i_generation number is normally
-			      changed only when new inode is created and it is
-			      particularly useful for network filesystems. The
-			      '_OLD' version of this ioctl is an alias for
-			      FS_IOC_GETVERSION.
-
- EXT4_IOC_SETVERSION
- EXT4_IOC_SETVERSION_OLD
-			      Set the inode i_generation number stored for
-			      each inode. The '_OLD' version of this ioctl
-			      is an alias for FS_IOC_SETVERSION.
-
- EXT4_IOC_GROUP_EXTEND	      This ioctl has the same purpose as the resize
-			      mount option. It allows to resize filesystem
-			      to the end of the last existing block group,
-			      further resize has to be done with resize2fs,
-			      either online, or offline. The argument points
-			      to the unsigned logn number representing the
-			      filesystem new block count.
-
- EXT4_IOC_MOVE_EXT	      Move the block extents from orig_fd (the one
-			      this ioctl is pointing to) to the donor_fd (the
-			      one specified in move_extent structure passed
-			      as an argument to this ioctl). Then, exchange
-			      inode metadata between orig_fd and donor_fd.
-			      This is especially useful for online
-			      defragmentation, because the allocator has the
-			      opportunity to allocate moved blocks better,
-			      ideally into one contiguous extent.
-
- EXT4_IOC_GROUP_ADD	      Add a new group descriptor to an existing or
-			      new group descriptor block. The new group
-			      descriptor is described by ext4_new_group_input
-			      structure, which is passed as an argument to
-			      this ioctl. This is especially useful in
-			      conjunction with EXT4_IOC_GROUP_EXTEND,
-			      which allows online resize of the filesystem
-			      to the end of the last existing block group.
-			      Those two ioctls combined is used in userspace
-			      online resize tool (e.g. resize2fs).
-
- EXT4_IOC_MIGRATE	      This ioctl operates on the filesystem itself.
-			      It converts (migrates) ext3 indirect block mapped
-			      inode to ext4 extent mapped inode by walking
-			      through indirect block mapping of the original
-			      inode and converting contiguous block ranges
-			      into ext4 extents of the temporary inode. Then,
-			      inodes are swapped. This ioctl might help, when
-			      migrating from ext3 to ext4 filesystem, however
-			      suggestion is to create fresh ext4 filesystem
-			      and copy data from the backup. Note, that
-			      filesystem has to support extents for this ioctl
-			      to work.
-
- EXT4_IOC_ALLOC_DA_BLKS	      Force all of the delay allocated blocks to be
-			      allocated to preserve application-expected ext3
-			      behaviour. Note that this will also start
-			      triggering a write of the data blocks, but this
-			      behaviour may change in the future as it is
-			      not necessary and has been done this way only
-			      for sake of simplicity.
-
- EXT4_IOC_RESIZE_FS	      Resize the filesystem to a new size.  The number
-			      of blocks of resized filesystem is passed in via
-			      64 bit integer argument.  The kernel allocates
-			      bitmaps and inode table, the userspace tool thus
-			      just passes the new number of blocks.
-
- EXT4_IOC_SWAP_BOOT	      Swap i_blocks and associated attributes
-			      (like i_blocks, i_size, i_flags, ...) from
-			      the specified inode with inode
-			      EXT4_BOOT_LOADER_INO (#5). This is typically
-			      used to store a boot loader in a secure part of
-			      the filesystem, where it can't be changed by a
-			      normal user by accident.
-			      The data blocks of the previous boot loader
-			      will be associated with the given inode.
-============================= =================================================
-
-References
-==========
-
-kernel source:	<file:fs/ext4/>
-		<file:fs/jbd2/>
-
-programs:	http://e2fsprogs.sourceforge.net/
-
-useful links:	http://fedoraproject.org/wiki/ext3-devel
-		http://www.bullopensource.org/ext4/
-		http://ext4.wiki.kernel.org/index.php/Main_Page
-		http://fedoraproject.org/wiki/Features/Ext4
diff --git a/Documentation/filesystems/ext4/ondisk/globals.rst b/Documentation/filesystems/ext4/globals.rst
index 368bf7662b96..368bf7662b96 100644
--- a/Documentation/filesystems/ext4/ondisk/globals.rst
+++ b/Documentation/filesystems/ext4/globals.rst
diff --git a/Documentation/filesystems/ext4/ondisk/group_descr.rst b/Documentation/filesystems/ext4/group_descr.rst
index 759827e5d2cf..0f783ed88592 100644
--- a/Documentation/filesystems/ext4/ondisk/group_descr.rst
+++ b/Documentation/filesystems/ext4/group_descr.rst
@@ -43,7 +43,7 @@ entire bitmap.
 The block group descriptor is laid out in ``struct ext4_group_desc``.
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -157,7 +157,7 @@ The block group descriptor is laid out in ``struct ext4_group_desc``.
 Block group flags can be any combination of the following:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 16 64
    :header-rows: 1
 
    * - Value
diff --git a/Documentation/filesystems/ext4/ondisk/ifork.rst b/Documentation/filesystems/ext4/ifork.rst
index 5dbe3b2b121a..b9816d5a896b 100644
--- a/Documentation/filesystems/ext4/ondisk/ifork.rst
+++ b/Documentation/filesystems/ext4/ifork.rst
@@ -68,7 +68,7 @@ The extent tree header is recorded in ``struct ext4_extent_header``,
 which is 12 bytes long:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -104,7 +104,7 @@ Internal nodes of the extent tree, also known as index nodes, are
 recorded as ``struct ext4_extent_idx``, and are 12 bytes long:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -134,7 +134,7 @@ Leaf nodes of the extent tree are recorded as ``struct ext4_extent``,
 and are also 12 bytes long:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -174,7 +174,7 @@ including) the checksum itself.
 ``struct ext4_extent_tail`` is 4 bytes long:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
diff --git a/Documentation/filesystems/ext4/index.rst b/Documentation/filesystems/ext4/index.rst
index 71121605558c..3be3e54d480d 100644
--- a/Documentation/filesystems/ext4/index.rst
+++ b/Documentation/filesystems/ext4/index.rst
@@ -1,17 +1,14 @@
 .. SPDX-License-Identifier: GPL-2.0
 
-===============
-ext4 Filesystem
-===============
-
-General usage and on-disk artifacts writen by ext4.  More documentation may
-be ported from the wiki as time permits.  This should be considered the
-canonical source of information as the details here have been reviewed by
-the ext4 community.
+===================================
+ext4 Data Structures and Algorithms
+===================================
 
 .. toctree::
-   :maxdepth: 5
+   :maxdepth: 6
    :numbered:
 
-   ext4
-   ondisk/index
+   about.rst
+   overview.rst
+   globals.rst
+   dynamic.rst
diff --git a/Documentation/filesystems/ext4/ondisk/inlinedata.rst b/Documentation/filesystems/ext4/inlinedata.rst
index d1075178ce0b..d1075178ce0b 100644
--- a/Documentation/filesystems/ext4/ondisk/inlinedata.rst
+++ b/Documentation/filesystems/ext4/inlinedata.rst
diff --git a/Documentation/filesystems/ext4/ondisk/inodes.rst b/Documentation/filesystems/ext4/inodes.rst
index 655ce898f3f5..6bd35e506b6f 100644
--- a/Documentation/filesystems/ext4/ondisk/inodes.rst
+++ b/Documentation/filesystems/ext4/inodes.rst
@@ -29,8 +29,9 @@ and the inode structure itself.
 The inode table entry is laid out in ``struct ext4_inode``.
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
+   :class: longtable
 
    * - Offset
      - Size
@@ -176,7 +177,7 @@ The inode table entry is laid out in ``struct ext4_inode``.
 The ``i_mode`` value is a combination of the following flags:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 16 64
    :header-rows: 1
 
    * - Value
@@ -227,7 +228,7 @@ The ``i_mode`` value is a combination of the following flags:
 The ``i_flags`` field is a combination of these values:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 16 64
    :header-rows: 1
 
    * - Value
@@ -314,7 +315,7 @@ The ``osd1`` field has multiple meanings depending on the creator:
 Linux:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -331,7 +332,7 @@ Linux:
 Hurd:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -346,7 +347,7 @@ Hurd:
 Masix:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -365,7 +366,7 @@ The ``osd2`` field has multiple meanings depending on the filesystem creator:
 Linux:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -402,7 +403,7 @@ Linux:
 Hurd:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -433,7 +434,7 @@ Hurd:
 Masix:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
diff --git a/Documentation/filesystems/ext4/ondisk/journal.rst b/Documentation/filesystems/ext4/journal.rst
index e7031af86876..ea613ee701f5 100644
--- a/Documentation/filesystems/ext4/ondisk/journal.rst
+++ b/Documentation/filesystems/ext4/journal.rst
@@ -48,7 +48,7 @@ Layout
 Generally speaking, the journal has this format:
 
 .. list-table::
-   :widths: 1 1 78
+   :widths: 16 48 16
    :header-rows: 1
 
    * - Superblock
@@ -76,7 +76,7 @@ The journal superblock will be in the next full block after the
 superblock.
 
 .. list-table::
-   :widths: 1 1 1 1 76
+   :widths: 12 12 12 32 12
    :header-rows: 1
 
    * - 1024 bytes of padding
@@ -98,7 +98,7 @@ Every block in the journal starts with a common 12-byte header
 ``struct journal_header_s``:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -124,7 +124,7 @@ Every block in the journal starts with a common 12-byte header
 The journal block type can be any one of:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 16 64
    :header-rows: 1
 
    * - Value
@@ -154,7 +154,7 @@ The journal superblock is recorded as ``struct journal_superblock_s``,
 which is 1024 bytes long:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -264,7 +264,7 @@ which is 1024 bytes long:
 The journal compat features are any combination of the following:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 16 64
    :header-rows: 1
 
    * - Value
@@ -278,7 +278,7 @@ The journal compat features are any combination of the following:
 The journal incompat features are any combination of the following:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 16 64
    :header-rows: 1
 
    * - Value
@@ -306,7 +306,7 @@ Journal checksum type codes are one of the following.  crc32 or crc32c are the
 most likely choices.
 
 .. list-table::
-   :widths: 1 79
+   :widths: 16 64
    :header-rows: 1
 
    * - Value
@@ -330,7 +330,7 @@ described by a data structure, but here is the block structure anyway.
 Descriptor blocks consume at least 36 bytes, but use a full block:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -355,7 +355,7 @@ defined as ``struct journal_block_tag3_s``, which looks like the
 following. The size is 16 or 32 bytes.
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -400,7 +400,7 @@ following. The size is 16 or 32 bytes.
 The journal tag flags are any combination of the following:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 16 64
    :header-rows: 1
 
    * - Value
@@ -421,7 +421,7 @@ is defined as ``struct journal_block_tag_s``, which looks like the
 following. The size is 8, 12, 24, or 28 bytes:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -471,7 +471,7 @@ JBD2\_FEATURE\_INCOMPAT\_CSUM\_V3 are set, the end of the block is a
 ``struct jbd2_journal_block_tail``, which looks like this:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -513,7 +513,7 @@ Revocation blocks are described in
 length, but use a full block:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -543,7 +543,7 @@ JBD2\_FEATURE\_INCOMPAT\_CSUM\_V3 are set, the end of the revocation
 block is a ``struct jbd2_journal_revoke_tail``, which has this format:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -567,7 +567,7 @@ The commit block is described by ``struct commit_header``, which is 32
 bytes long (but uses a full block):
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
diff --git a/Documentation/filesystems/ext4/ondisk/mmp.rst b/Documentation/filesystems/ext4/mmp.rst
index b7d7a3137f80..25660981d93c 100644
--- a/Documentation/filesystems/ext4/ondisk/mmp.rst
+++ b/Documentation/filesystems/ext4/mmp.rst
@@ -32,7 +32,7 @@ The checksum is calculated against the FS UUID and the MMP structure.
 The MMP structure (``struct mmp_struct``) is as follows:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 12 20 40
    :header-rows: 1
 
    * - Offset
diff --git a/Documentation/filesystems/ext4/ondisk/index.rst b/Documentation/filesystems/ext4/ondisk/index.rst
deleted file mode 100644
index f7d082c3a435..000000000000
--- a/Documentation/filesystems/ext4/ondisk/index.rst
+++ /dev/null
@@ -1,9 +0,0 @@
-.. SPDX-License-Identifier: GPL-2.0
-
-==============================
-Data Structures and Algorithms
-==============================
-.. include:: about.rst
-.. include:: overview.rst
-.. include:: globals.rst
-.. include:: dynamic.rst
diff --git a/Documentation/filesystems/ext4/ondisk/overview.rst b/Documentation/filesystems/ext4/overview.rst
index cbab18baba12..cbab18baba12 100644
--- a/Documentation/filesystems/ext4/ondisk/overview.rst
+++ b/Documentation/filesystems/ext4/overview.rst
diff --git a/Documentation/filesystems/ext4/ondisk/special_inodes.rst b/Documentation/filesystems/ext4/special_inodes.rst
index a82f70c9baeb..9061aabba827 100644
--- a/Documentation/filesystems/ext4/ondisk/special_inodes.rst
+++ b/Documentation/filesystems/ext4/special_inodes.rst
@@ -6,7 +6,7 @@ Special inodes
 ext4 reserves some inode for special features, as follows:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 6 70
    :header-rows: 1
 
    * - inode Number
diff --git a/Documentation/filesystems/ext4/ondisk/super.rst b/Documentation/filesystems/ext4/super.rst
index 5f81dd87e0b9..04ff079a2acf 100644
--- a/Documentation/filesystems/ext4/ondisk/super.rst
+++ b/Documentation/filesystems/ext4/super.rst
@@ -19,7 +19,7 @@ The ext4 superblock is laid out as follows in
 ``struct ext4_super_block``:
 
 .. list-table::
-   :widths: 1 1 1 77
+   :widths: 8 8 24 40
    :header-rows: 1
 
    * - Offset
@@ -483,7 +483,7 @@ The ext4 superblock is laid out as follows in
 The superblock state is some combination of the following:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 8 72
    :header-rows: 1
 
    * - Value
@@ -500,7 +500,7 @@ The superblock state is some combination of the following:
 The superblock error policy is one of the following:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 8 72
    :header-rows: 1
 
    * - Value
@@ -517,7 +517,7 @@ The superblock error policy is one of the following:
 The filesystem creator is one of the following:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 8 72
    :header-rows: 1
 
    * - Value
@@ -538,7 +538,7 @@ The filesystem creator is one of the following:
 The superblock revision is one of the following:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 8 72
    :header-rows: 1
 
    * - Value
@@ -556,7 +556,7 @@ The superblock compatible features field is a combination of any of the
 following:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 16 64
    :header-rows: 1
 
    * - Value
@@ -595,7 +595,7 @@ The superblock incompatible features field is a combination of any of the
 following:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 16 64
    :header-rows: 1
 
    * - Value
@@ -647,7 +647,7 @@ The superblock read-only compatible features field is a combination of any of
 the following:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 16 64
    :header-rows: 1
 
    * - Value
@@ -702,7 +702,7 @@ the following:
 The ``s_def_hash_version`` field is one of the following:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 8 72
    :header-rows: 1
 
    * - Value
@@ -725,7 +725,7 @@ The ``s_def_hash_version`` field is one of the following:
 The ``s_default_mount_opts`` field is any combination of the following:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 8 72
    :header-rows: 1
 
    * - Value
@@ -767,7 +767,7 @@ The ``s_default_mount_opts`` field is any combination of the following:
 The ``s_flags`` field is any combination of the following:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 8 72
    :header-rows: 1
 
    * - Value
@@ -784,7 +784,7 @@ The ``s_flags`` field is any combination of the following:
 The ``s_encrypt_algos`` list can contain any of the following:
 
 .. list-table::
-   :widths: 1 79
+   :widths: 8 72
    :header-rows: 1
 
    * - Value