Re: [linux-kernel-mentees] [PATCH v5] Doc : fs : convert xfs.txt to ReST

Darrick J. Wong
2019-07-02T15:23:14Z

> Convert xfs.txt to ReST, rename and fix broken references, consequently.
>
> Make the name "value" in "option=value" look like a variable (that it probably
> is), by embedding in angle "<>" brackets, rather than something predifined
> elsewhere. This is inline with the conventions in manuals.
>
> Also, make defaults of boolean options prefixed with "(*)". This is so that
> options can be compressed to "[no]option" and on a single line, which renders
> consistently and nicely in htmldocs.
>
> lastly, enforce a "one option, one definition" policy to keep things
> consistent and simple.
>
>
> Signed-off-by: Sheriff Esseson <sheriffesseson@gmail.com>
> ---
>
> v5 aims to comply with the guiding comments on its previous versions.
>
> Documentation/filesystems/dax.txt | 2 +-
> Documentation/filesystems/index.rst | 5 +-
> Documentation/filesystems/xfs.rst | 468 +++++++++++++++++++++++++++
> Documentation/filesystems/xfs.txt | 470 ----------------------------
> MAINTAINERS | 2 +-
> 5 files changed, 473 insertions(+), 474 deletions(-)
> create mode 100644 Documentation/filesystems/xfs.rst
> delete mode 100644 Documentation/filesystems/xfs.txt
>
> diff --git a/Documentation/filesystems/dax.txt b/Documentation/filesystems/dax.txt
> index 6d2c0d340..c333285b8 100644
> --- a/Documentation/filesystems/dax.txt
> +++ b/Documentation/filesystems/dax.txt
> @@ -76,7 +76,7 @@ exposure of uninitialized data through mmap.
> These filesystems may be used for inspiration:
> - ext2: see Documentation/filesystems/ext2.txt
> - ext4: see Documentation/filesystems/ext4/
> -- xfs: see Documentation/filesystems/xfs.txt
> +- xfs: see Documentation/filesystems/xfs.rst
>
>
> Handling Media Errors
> diff --git a/Documentation/filesystems/index.rst b/Documentation/filesystems/index.rst
> index 1131c34d7..a4cf5fca4 100644
> --- a/Documentation/filesystems/index.rst
> +++ b/Documentation/filesystems/index.rst
> @@ -16,7 +16,7 @@ algorithms work.
> .. toctree::
> :maxdepth: 2
>
> - path-lookup.rst
> + path-lookup
> api-summary
> splice
>
> @@ -40,4 +40,5 @@ Documentation for individual filesystem types can be found here.
> .. toctree::
> :maxdepth: 2
>
> - binderfs.rst
> + binderfs
> + xfs
> diff --git a/Documentation/filesystems/xfs.rst b/Documentation/filesystems/xfs.rst
> new file mode 100644
> index 000000000..d36ef042c
> --- /dev/null
> +++ b/Documentation/filesystems/xfs.rst
> @@ -0,0 +1,468 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +======================
> +The SGI XFS Filesystem
> +======================
> +
> +XFS is a high performance journaling filesystem which originated
> +on the SGI IRIX platform. It is completely multi-threaded, can
> +support large files and large filesystems, extended attributes,
> +variable block sizes, is extent based, and makes extensive use of
> +Btrees (directories, extents, free space) to aid both performance
> +and scalability.
> +
> +Refer to the documentation at https://xfs.wiki.kernel.org/
> +for further details. This implementation is on-disk compatible
> +with the IRIX version of XFS.
> +
> +
> +Mount Options
> +=============
> +
> +When mounting an XFS filesystem, the following options are accepted. For
> +boolean mount options, the names with the "(*)" prefix is the default behaviour.
> +For example, take a behaviour enabled by default to be a one (1) or, a zero (0)
> +otherwise, ``(*)[no]default`` would be 0 while ``[no](*)default`` , a 1.

That's really confusing. Does this mean that I can pass discard=1 now?

(no)

I also don't really understand why we need to cram so much into a single
line. Why not just:

discard
nodiscard (default)
Something something discard chomps on free space, chomp chomp
a chewy chomp, pretend I wrote the real text here, etc.

Or if you really want the single-line header...

[no]discard
Something something discard chomps on free space, chomp chomp
a chewy chomp, pretend I wrote the real text here, etc.

''nodiscard'' is the default setting.

Please don't introduce '1's and '0's here because there are other parts
of xfs where you /can/ enable or disable features by saying "foo=0" or
"foo=1".

There's probably more to say but the text reflowing since v1 makes this
patch unreviewable because ugh 1000-line diff.

--D

> +
> + allocsize=<size>
> + Sets the buffered I/O end-of-file preallocation size when doing delayed
> + allocation writeout (default size is 64KiB). Valid values for this
> + option are page size (typically 4KiB) through to 1GiB, inclusive, in
> + power-of-2 increments.
> +
> + The default behaviour is for dynamic end-of-file preallocation size,
> + which uses a set of heuristics to optimise the preallocation size based
> + on the current allocation patterns within the file and the access
> + patterns to the file. Specifying a fixed allocsize value turns off the
> + dynamic behaviour.
> +
> + [no]attr2
> + The options enable/disable an "opportunistic" improvement to be made in
> + the way inline extended attributes are stored on-disk. When the new
> + form is used for the first time when ``attr2`` is selected (either when
> + setting or removing extended attributes) the on-disk superblock feature
> + bit field will be updated to reflect this format being in use.
> +
> + The default behaviour is determined by the on-disk feature bit
> + indicating that ``attr2`` behaviour is active. If either mount option is
> + set, then that becomes the new default used by the filesystem. However
> + on CRC enabled filesystems, the ``attr2`` format is always used , and so
> + will reject the ``noattr2`` mount option if it is set.
> +
> + (*)[no]discard
> + Enable/disable the issuing of commands to let the block device reclaim
> + space freed by the filesystem. This is useful for SSD devices, thinly
> + provisioned LUNs and virtual machine images, but may have a performance
> + impact.
> +
> + Note: It is currently recommended that you use the ``fstrim``
> + application to discard unused blocks rather than the ``discard`` mount
> + option because the performance impact of this option is quite severe.
> +
> + grpid/bsdgroups
> + nogrpid/(*)sysvgroups
> + These options define what group ID a newly created file gets. When
> + ``grpid`` is set, it takes the group ID of the directory in which it is
> + created; otherwise it takes the ``fsgid`` of the current process, unless
> + the directory has the ``setgid`` bit set, in which case it takes the
> + ``gid`` from the parent directory, and also gets the ``setgid`` bit set
> + if it is a directory itself.
> +
> + filestreams
> + Make the data allocator use the filestreams allocation mode across the
> + entire filesystem rather than just on directories configured to use it.
> +
> + (*)[no]ikeep
> + When ``ikeep`` is specified, XFS does not delete empty inode clusters
> + and keeps them around on disk. When ``noikeep`` is specified, empty
> + inode clusters are returned to the free space pool.
> +
> + inode32 | (*)inode64
> + When ``inode32`` is specified, it indicates that XFS limits inode
> + creation to locations which will not result in inode numbers with more
> + than 32 bits of significance.
> +
> + When ``inode64`` is specified, it indicates that XFS is allowed to
> + create inodes at any location in the filesystem, including those which
> + will result in inode numbers occupying more than 32 bits of
> + significance.
> +
> + ``inode32`` is provided for backwards compatibility with older systems
> + and applications, since 64 bits inode numbers might cause problems for
> + some applications that cannot handle large inode numbers. If
> + applications are in use which do not handle inode numbers bigger than 32
> + bits, the ``inode32`` option should be specified.
> +
> +
> + (*)[no]largeio
> + If ``nolargeio`` is specified, the optimal I/O reported in st_blksize by
> + **stat(2)** will be as small as possible to allow user applications to
> + avoid inefficient read/modify/write I/O. This is typically the page
> + size of the machine, as this is the granularity of the page cache.
> +
> + If ``largeio`` is specified, a filesystem that was created with a
> + ``swidth`` specified will return the ``swidth`` value (in bytes) in
> + st_blksize. If the filesystem does not have a ``swidth`` specified but
> + does specify an ``allocsize`` then ``allocsize`` (in bytes) will be
> + returned instead. Otherwise the behaviour is the same as if
> + ``nolargeio`` was specified.
> +
> + logbufs=<value>
> + Set the number of in-memory log buffers to ``value``. Valid numbers
> + range from 2-8 inclusive.
> +
> + The default value is 8 buffers.
> +
> + If the memory cost of 8 log buffers is too high on small systems, then
> + it may be reduced at some cost to performance on metadata intensive
> + workloads. The ``logbsize`` option below controls the size of each
> + buffer and so is also relevant to this case.
> +
> + logbsize=<value>
> + Set the size of each in-memory log buffer to ``value``. The size may be
> + specified in bytes, or in kilobytes with a "k" suffix. Valid sizes for
> + version 1 and version 2 logs are 16384 (16k) and 32768 (32k). Valid
> + sizes for version 2 logs also include 65536 (64k), 131072 (128k) and
> + 262144 (256k). The ``logbsize`` must be an integer multiple of the
> + "log stripe unit" configured at mkfs time.
> +
> + The default value for for version 1 logs is 32768, while the default
> + value for version 2 logs is ``MAX(32768, log_sunit)``.
> +
> + logdev=<device>
> + Use ``device`` as an external log (metadata journal). In an XFS
> + filesystem, the log device can be separate from the data device or
> + contained within it.
> +
> + rtdev=<device>
> + An XFS filesystem has up to three parts: a data section, a log section,
> + and a real-time section. The real-time section is optional. If
> + enabled, ``rtdev`` sets ``device`` to be used as an external real-time
> + section, similar to ``logdev`` above.
> +
> + noalign
> + Data allocations will not be aligned at stripe unit boundaries. This is
> + only relevant to filesystems created with non-zero data alignment
> + parameters (sunit, swidth) by mkfs.
> +
> + norecovery
> + The filesystem will be mounted without running log recovery. If the
> + filesystem was not cleanly unmounted, it is likely to be inconsistent
> + when mounted in ``norecovery`` mode. Some files or directories may not
> + be accessible because of this. Filesystems mounted ``norecovery`` must
> + be mounted read-only or the mount will fail.
> +
> + nouuid
> + Don't check for double mounted file systems using the file system uuid.
> + This is useful to mount LVM snapshot volumes, and often used in
> + combination with ``norecovery`` for mounting read-only snapshots.
> +
> + noquota
> + Forcibly turns off all quota accounting and enforcement
> + within the filesystem.
> +
> + uquota/usrquota/uqnoenforce/quota
> + User disk quota accounting enabled, and limits (optionally) enforced.
> + Refer to **xfs_quota(8)** for further details.
> +
> + gquota/grpquota/gqnoenforce
> + Group disk quota accounting enabled and limits (optionally) enforced.
> + Refer to **xfs_quota(8)** for further details.
> +
> + pquota/prjquota/pqnoenforce
> + Project disk quota accounting enabled and limits (optionally) enforced.
> + Refer to **xfs_quota(8)** for further details.
> +
> + sunit=<value>
> + Used to specify the stripe unit for a RAID device or (in conjunction
> + with ``swidth`` below) a stripe volume. ``value`` must be specified in
> + 512-byte block units. This option is only relevant to filesystems that
> + were created with non-zero data alignment parameters.
> +
> + The ``sunit`` parameter specified must be compatible with the existing
> + filesystem alignment characteristics. In general, that means the only
> + valid changes to ``sunit`` are increasing it by a power-of-2 multiple.
> +
> + Typically, this mount option is necessary only after an underlying RAID
> + device has had its geometry modified, such as adding a new disk to a
> + RAID5 lun and reshaping it.
> +
> + swidth=<value>
> + Used to specify the stripe width for a RAID device or (in conjunction
> + with ``sunit`` above) a stripe volume. ``value`` must be specified in
> + 512-byte block units. This option, like ``sunit`` above, is only
> + relevant to filesystems that were created with non-zero data alignment
> + parameters.
> +
> + The ``swidth`` parameter specified must be compatible with the existing
> + filesystem alignment characteristics. In general, that means the only
> + valid swidth values are any integer multiple of a valid ``sunit`` value.
> +
> + Typically, this mount option is necessary only after an underlying RAID
> + device has had its geometry modified, such as adding a new disk to a
> + RAID5 lun and reshaping it.
> +
> +
> + swalloc
> + Data allocations will be rounded up to stripe width boundaries when the
> + current end of file is being extended and the file size is larger than
> + the stripe width size.
> +
> + wsync
> + When specified, all filesystem namespace operations are executed
> + synchronously. This ensures that when the namespace operation (create,
> + unlink, etc) completes, the change to the namespace is on stable
> + storage. This is useful in HA setups where failover must not result in
> + clients seeing inconsistent namespace presentation during or after a
> + failover event.
> +
> +
> +Deprecated Mount Options
> +========================
> +
> + Name Removal Schedule
> + ---- ----------------
> +
> +
> +Removed Mount Options
> +=====================
> +
> + Name Removed
> + ---- -------
> + delaylog/nodelaylog v4.0
> + ihashsize v4.0
> + irixsgid v4.0
> + osyncisdsync/osyncisosync v4.0
> + barrier v4.19
> + nobarrier v4.19
> +
> +
> +sysctls
> +=======
> +
> +The following sysctls are available for the XFS filesystem:
> +
> + fs.xfs.stats_clear (Min: 0 Default: 0 Max: 1)
> + Setting this to "1" clears accumulated XFS statistics
> + in /proc/fs/xfs/stat. It then immediately resets to "0".
> +
> + fs.xfs.xfssyncd_centisecs (Min: 100 Default: 3000 Max: 720000)
> + The interval at which the filesystem flushes metadata
> + out to disk and runs internal cache cleanup routines.
> +
> + fs.xfs.filestream_centisecs (Min: 1 Default: 3000 Max: 360000)
> + The interval at which the filesystem ages filestreams cache
> + references and returns timed-out AGs back to the free stream
> + pool.
> +
> + fs.xfs.speculative_prealloc_lifetime
> + (Units: seconds Min: 1 Default: 300 Max: 86400)
> + The interval at which the background scanning for inodes
> + with unused speculative preallocation runs. The scan
> + removes unused preallocation from clean inodes and releases
> + the unused space back to the free pool.
> +
> + fs.xfs.error_level (Min: 0 Default: 3 Max: 11)
> + A volume knob for error reporting when internal errors occur.
> + This will generate detailed messages & backtraces for filesystem
> + shutdowns, for example. Current threshold values are:
> +
> + XFS_ERRLEVEL_OFF: 0
> + XFS_ERRLEVEL_LOW: 1
> + XFS_ERRLEVEL_HIGH: 5
> +
> + fs.xfs.panic_mask (Min: 0 Default: 0 Max: 256)
> + Causes certain error conditions to call BUG(). Value is a bitmask;
> + OR together the tags which represent errors which should cause panics:
> +
> + XFS_NO_PTAG 0
> + XFS_PTAG_IFLUSH 0x00000001
> + XFS_PTAG_LOGRES 0x00000002
> + XFS_PTAG_AILDELETE 0x00000004
> + XFS_PTAG_ERROR_REPORT 0x00000008
> + XFS_PTAG_SHUTDOWN_CORRUPT 0x00000010
> + XFS_PTAG_SHUTDOWN_IOERROR 0x00000020
> + XFS_PTAG_SHUTDOWN_LOGERROR 0x00000040
> + XFS_PTAG_FSBLOCK_ZERO 0x00000080
> + XFS_PTAG_VERIFIER_ERROR 0x00000100
> +
> + This option is intended for debugging only.
> +
> + fs.xfs.irix_symlink_mode (Min: 0 Default: 0 Max: 1)
> + Controls whether symlinks are created with mode 0777 (default)
> + or whether their mode is affected by the umask (irix mode).
> +
> + fs.xfs.irix_sgid_inherit (Min: 0 Default: 0 Max: 1)
> + Controls files created in SGID directories.
> + If the group ID of the new file does not match the effective group
> + ID or one of the supplementary group IDs of the parent dir, the
> + ISGID bit is cleared if the irix_sgid_inherit compatibility sysctl
> + is set.
> +
> + fs.xfs.inherit_sync (Min: 0 Default: 1 Max: 1)
> + Setting this to "1" will cause the "sync" flag set
> + by the **xfs_io(8)** chattr command on a directory to be
> + inherited by files in that directory.
> +
> + fs.xfs.inherit_nodump (Min: 0 Default: 1 Max: 1)
> + Setting this to "1" will cause the "nodump" flag set
> + by the **xfs_io(8)** chattr command on a directory to be
> + inherited by files in that directory.
> +
> + fs.xfs.inherit_noatime (Min: 0 Default: 1 Max: 1)
> + Setting this to "1" will cause the "noatime" flag set
> + by the **xfs_io(8)** chattr command on a directory to be
> + inherited by files in that directory.
> +
> + fs.xfs.inherit_nosymlinks (Min: 0 Default: 1 Max: 1)
> + Setting this to "1" will cause the "nosymlinks" flag set
> + by the **xfs_io(8)** chattr command on a directory to be
> + inherited by files in that directory.
> +
> + fs.xfs.inherit_nodefrag (Min: 0 Default: 1 Max: 1)
> + Setting this to "1" will cause the "nodefrag" flag set
> + by the **xfs_io(8)** chattr command on a directory to be
> + inherited by files in that directory.
> +
> + fs.xfs.rotorstep (Min: 1 Default: 1 Max: 256)
> + In "inode32" allocation mode, this option determines how many
> + files the allocator attempts to allocate in the same allocation
> + group before moving to the next allocation group. The intent
> + is to control the rate at which the allocator moves between
> + allocation groups when allocating extents for new files.
> +
> +Deprecated Sysctls
> +==================
> +
> +None at present.
> +
> +
> +Removed Sysctls
> +===============
> +
> + Name Removed
> + ---- -------
> + fs.xfs.xfsbufd_centisec v4.0
> + fs.xfs.age_buffer_centisecs v4.0
> +
> +
> +Error handling
> +==============
> +
> +XFS can act differently according to the type of error found during its
> +operation. The implementation introduces the following concepts to the error
> +handler:
> +
> + -failure speed:
> + Defines how fast XFS should propagate an error upwards when a specific
> + error is found during the filesystem operation. It can propagate
> + immediately, after a defined number of retries, after a set time period,
> + or simply retry forever.
> +
> + -error classes:
> + Specifies the subsystem the error configuration will apply to, such as
> + metadata IO or memory allocation. Different subsystems will have
> + different error handlers for which behaviour can be configured.
> +
> + -error handlers:
> + Defines the behavior for a specific error.
> +
> +The filesystem behavior during an error can be set via sysfs files. Each
> +error handler works independently - the first condition met by an error handler
> +for a specific class will cause the error to be propagated rather than reset and
> +retried.
> +
> +The action taken by the filesystem when the error is propagated is context
> +dependent - it may cause a shut down in the case of an unrecoverable error,
> +it may be reported back to userspace, or it may even be ignored because
> +there's nothing useful we can with the error or anyone we can report it to (e.g.
> +during unmount).
> +
> +The configuration files are organized into the following hierarchy for each
> +mounted filesystem:
> +
> + /sys/fs/xfs/<dev>/error/<class>/<error>/
> +
> +Where:
> + <dev>
> + The short device name of the mounted filesystem. This is the same device
> + name that shows up in XFS kernel error messages as "XFS(<dev>): ..."
> +
> + <class>
> + The subsystem the error configuration belongs to. As of 4.9, the defined
> + classes are:
> +
> + - "metadata": applies metadata buffer write IO
> +
> + <error>
> + The individual error handler configurations.
> +
> +
> +Each filesystem has "global" error configuration options defined in their top
> +level directory:
> +
> + /sys/fs/xfs/<dev>/error/
> +
> + fail_at_unmount (Min: 0 Default: 1 Max: 1)
> + Defines the filesystem error behavior at unmount time.
> +
> + If set to a value of 1, XFS will override all other error configurations
> + during unmount and replace them with "immediate fail" characteristics.
> + i.e. no retries, no retry timeout. This will always allow unmount to
> + succeed when there are persistent errors present.
> +
> + If set to 0, the configured retry behaviour will continue until all
> + retries and/or timeouts have been exhausted. This will delay unmount
> + completion when there are persistent errors, and it may prevent the
> + filesystem from ever unmounting fully in the case of "retry forever"
> + handler configurations.
> +
> + Note: there is no guarantee that fail_at_unmount can be set while an
> + unmount is in progress. It is possible that the sysfs entries are
> + removed by the unmounting filesystem before a "retry forever" error
> + handler configuration causes unmount to hang, and hence the filesystem
> + must be configured appropriately before unmount begins to prevent
> + unmount hangs.
> +
> +Each filesystem has specific error class handlers that define the error
> +propagation behaviour for specific errors. There is also a "default" error
> +handler defined, which defines the behaviour for all errors that don't have
> +specific handlers defined. Where multiple retry constraints are configuredi for
> +a single error, the first retry configuration that expires will cause the error
> +to be propagated. The handler configurations are found in the directory:
> +
> + /sys/fs/xfs/<dev>/error/<class>/<error>/
> +
> + max_retries (Min: -1 Default: Varies Max: INTMAX)
> + Defines the allowed number of retries of a specific error before
> + the filesystem will propagate the error. The retry count for a given
> + error context (e.g. a specific metadata buffer) is reset every time
> + there is a successful completion of the operation.
> +
> + Setting the value to "-1" will cause XFS to retry forever for this
> + specific error.
> +
> + Setting the value to "0" will cause XFS to fail immediately when the
> + specific error is reported.
> +
> + Setting the value to "N" (where 0 < N < Max) will make XFS retry the
> + operation "N" times before propagating the error.
> +
> + retry_timeout_seconds (Min: -1 Default: Varies Max: 1 day)
> + Define the amount of time (in seconds) that the filesystem is
> + allowed to retry its operations when the specific error is
> + found.
> +
> + Setting the value to "-1" will allow XFS to retry forever for this
> + specific error.
> +
> + Setting the value to "0" will cause XFS to fail immediately when the
> + specific error is reported.
> +
> + Setting the value to "N" (where 0 < N < Max) will allow XFS to retry the
> + operation for up to "N" seconds before propagating the error.
> +
> +Note: The default behaviour for a specific error handler is dependent on both
> +the class and error context. For example, the default values for
> +"metadata/ENODEV" are "0" rather than "-1" so that this error handler defaults
> +to "fail immediately" behaviour. This is done because ENODEV is a fatal,
> +unrecoverable error no matter how many times the metadata IO is retried.
> diff --git a/Documentation/filesystems/xfs.txt b/Documentation/filesystems/xfs.txt
> deleted file mode 100644
> index a5cbb5e0e..000000000
> --- a/Documentation/filesystems/xfs.txt
> +++ /dev/null
> @@ -1,470 +0,0 @@
> -
> -The SGI XFS Filesystem
> -======================
> -
> -XFS is a high performance journaling filesystem which originated
> -on the SGI IRIX platform. It is completely multi-threaded, can
> -support large files and large filesystems, extended attributes,
> -variable block sizes, is extent based, and makes extensive use of
> -Btrees (directories, extents, free space) to aid both performance
> -and scalability.
> -
> -Refer to the documentation at https://xfs.wiki.kernel.org/
> -for further details. This implementation is on-disk compatible
> -with the IRIX version of XFS.
> -
> -
> -Mount Options
> -=============
> -
> -When mounting an XFS filesystem, the following options are accepted.
> -For boolean mount options, the names with the (*) suffix is the
> -default behaviour.
> -
> - allocsize=size
> - Sets the buffered I/O end-of-file preallocation size when
> - doing delayed allocation writeout (default size is 64KiB).
> - Valid values for this option are page size (typically 4KiB)
> - through to 1GiB, inclusive, in power-of-2 increments.
> -
> - The default behaviour is for dynamic end-of-file
> - preallocation size, which uses a set of heuristics to
> - optimise the preallocation size based on the current
> - allocation patterns within the file and the access patterns
> - to the file. Specifying a fixed allocsize value turns off
> - the dynamic behaviour.
> -
> - attr2
> - noattr2
> - The options enable/disable an "opportunistic" improvement to
> - be made in the way inline extended attributes are stored
> - on-disk. When the new form is used for the first time when
> - attr2 is selected (either when setting or removing extended
> - attributes) the on-disk superblock feature bit field will be
> - updated to reflect this format being in use.
> -
> - The default behaviour is determined by the on-disk feature
> - bit indicating that attr2 behaviour is active. If either
> - mount option it set, then that becomes the new default used
> - by the filesystem.
> -
> - CRC enabled filesystems always use the attr2 format, and so
> - will reject the noattr2 mount option if it is set.
> -
> - discard
> - nodiscard (*)
> - Enable/disable the issuing of commands to let the block
> - device reclaim space freed by the filesystem. This is
> - useful for SSD devices, thinly provisioned LUNs and virtual
> - machine images, but may have a performance impact.
> -
> - Note: It is currently recommended that you use the fstrim
> - application to discard unused blocks rather than the discard
> - mount option because the performance impact of this option
> - is quite severe.
> -
> - grpid/bsdgroups
> - nogrpid/sysvgroups (*)
> - These options define what group ID a newly created file
> - gets. When grpid is set, it takes the group ID of the
> - directory in which it is created; otherwise it takes the
> - fsgid of the current process, unless the directory has the
> - setgid bit set, in which case it takes the gid from the
> - parent directory, and also gets the setgid bit set if it is
> - a directory itself.
> -
> - filestreams
> - Make the data allocator use the filestreams allocation mode
> - across the entire filesystem rather than just on directories
> - configured to use it.
> -
> - ikeep
> - noikeep (*)
> - When ikeep is specified, XFS does not delete empty inode
> - clusters and keeps them around on disk. When noikeep is
> - specified, empty inode clusters are returned to the free
> - space pool.
> -
> - inode32
> - inode64 (*)
> - When inode32 is specified, it indicates that XFS limits
> - inode creation to locations which will not result in inode
> - numbers with more than 32 bits of significance.
> -
> - When inode64 is specified, it indicates that XFS is allowed
> - to create inodes at any location in the filesystem,
> - including those which will result in inode numbers occupying
> - more than 32 bits of significance.
> -
> - inode32 is provided for backwards compatibility with older
> - systems and applications, since 64 bits inode numbers might
> - cause problems for some applications that cannot handle
> - large inode numbers. If applications are in use which do
> - not handle inode numbers bigger than 32 bits, the inode32
> - option should be specified.
> -
> -
> - largeio
> - nolargeio (*)
> - If "nolargeio" is specified, the optimal I/O reported in
> - st_blksize by stat(2) will be as small as possible to allow
> - user applications to avoid inefficient read/modify/write
> - I/O. This is typically the page size of the machine, as
> - this is the granularity of the page cache.
> -
> - If "largeio" specified, a filesystem that was created with a
> - "swidth" specified will return the "swidth" value (in bytes)
> - in st_blksize. If the filesystem does not have a "swidth"
> - specified but does specify an "allocsize" then "allocsize"
> - (in bytes) will be returned instead. Otherwise the behaviour
> - is the same as if "nolargeio" was specified.
> -
> - logbufs=value
> - Set the number of in-memory log buffers. Valid numbers
> - range from 2-8 inclusive.
> -
> - The default value is 8 buffers.
> -
> - If the memory cost of 8 log buffers is too high on small
> - systems, then it may be reduced at some cost to performance
> - on metadata intensive workloads. The logbsize option below
> - controls the size of each buffer and so is also relevant to
> - this case.
> -
> - logbsize=value
> - Set the size of each in-memory log buffer. The size may be
> - specified in bytes, or in kilobytes with a "k" suffix.
> - Valid sizes for version 1 and version 2 logs are 16384 (16k)
> - and 32768 (32k). Valid sizes for version 2 logs also
> - include 65536 (64k), 131072 (128k) and 262144 (256k). The
> - logbsize must be an integer multiple of the log
> - stripe unit configured at mkfs time.
> -
> - The default value for for version 1 logs is 32768, while the
> - default value for version 2 logs is MAX(32768, log_sunit).
> -
> - logdev=device and rtdev=device
> - Use an external log (metadata journal) and/or real-time device.
> - An XFS filesystem has up to three parts: a data section, a log
> - section, and a real-time section. The real-time section is
> - optional, and the log section can be separate from the data
> - section or contained within it.
> -
> - noalign
> - Data allocations will not be aligned at stripe unit
> - boundaries. This is only relevant to filesystems created
> - with non-zero data alignment parameters (sunit, swidth) by
> - mkfs.
> -
> - norecovery
> - The filesystem will be mounted without running log recovery.
> - If the filesystem was not cleanly unmounted, it is likely to
> - be inconsistent when mounted in "norecovery" mode.
> - Some files or directories may not be accessible because of this.
> - Filesystems mounted "norecovery" must be mounted read-only or
> - the mount will fail.
> -
> - nouuid
> - Don't check for double mounted file systems using the file
> - system uuid. This is useful to mount LVM snapshot volumes,
> - and often used in combination with "norecovery" for mounting
> - read-only snapshots.
> -
> - noquota
> - Forcibly turns off all quota accounting and enforcement
> - within the filesystem.
> -
> - uquota/usrquota/uqnoenforce/quota
> - User disk quota accounting enabled, and limits (optionally)
> - enforced. Refer to xfs_quota(8) for further details.
> -
> - gquota/grpquota/gqnoenforce
> - Group disk quota accounting enabled and limits (optionally)
> - enforced. Refer to xfs_quota(8) for further details.
> -
> - pquota/prjquota/pqnoenforce
> - Project disk quota accounting enabled and limits (optionally)
> - enforced. Refer to xfs_quota(8) for further details.
> -
> - sunit=value and swidth=value
> - Used to specify the stripe unit and width for a RAID device
> - or a stripe volume. "value" must be specified in 512-byte
> - block units. These options are only relevant to filesystems
> - that were created with non-zero data alignment parameters.
> -
> - The sunit and swidth parameters specified must be compatible
> - with the existing filesystem alignment characteristics. In
> - general, that means the only valid changes to sunit are
> - increasing it by a power-of-2 multiple. Valid swidth values
> - are any integer multiple of a valid sunit value.
> -
> - Typically the only time these mount options are necessary if
> - after an underlying RAID device has had it's geometry
> - modified, such as adding a new disk to a RAID5 lun and
> - reshaping it.
> -
> - swalloc
> - Data allocations will be rounded up to stripe width boundaries
> - when the current end of file is being extended and the file
> - size is larger than the stripe width size.
> -
> - wsync
> - When specified, all filesystem namespace operations are
> - executed synchronously. This ensures that when the namespace
> - operation (create, unlink, etc) completes, the change to the
> - namespace is on stable storage. This is useful in HA setups
> - where failover must not result in clients seeing
> - inconsistent namespace presentation during or after a
> - failover event.
> -
> -
> -Deprecated Mount Options
> -========================
> -
> - Name Removal Schedule
> - ---- ----------------
> -
> -
> -Removed Mount Options
> -=====================
> -
> - Name Removed
> - ---- -------
> - delaylog/nodelaylog v4.0
> - ihashsize v4.0
> - irixsgid v4.0
> - osyncisdsync/osyncisosync v4.0
> - barrier v4.19
> - nobarrier v4.19
> -
> -
> -sysctls
> -=======
> -
> -The following sysctls are available for the XFS filesystem:
> -
> - fs.xfs.stats_clear (Min: 0 Default: 0 Max: 1)
> - Setting this to "1" clears accumulated XFS statistics
> - in /proc/fs/xfs/stat. It then immediately resets to "0".
> -
> - fs.xfs.xfssyncd_centisecs (Min: 100 Default: 3000 Max: 720000)
> - The interval at which the filesystem flushes metadata
> - out to disk and runs internal cache cleanup routines.
> -
> - fs.xfs.filestream_centisecs (Min: 1 Default: 3000 Max: 360000)
> - The interval at which the filesystem ages filestreams cache
> - references and returns timed-out AGs back to the free stream
> - pool.
> -
> - fs.xfs.speculative_prealloc_lifetime
> - (Units: seconds Min: 1 Default: 300 Max: 86400)
> - The interval at which the background scanning for inodes
> - with unused speculative preallocation runs. The scan
> - removes unused preallocation from clean inodes and releases
> - the unused space back to the free pool.
> -
> - fs.xfs.error_level (Min: 0 Default: 3 Max: 11)
> - A volume knob for error reporting when internal errors occur.
> - This will generate detailed messages & backtraces for filesystem
> - shutdowns, for example. Current threshold values are:
> -
> - XFS_ERRLEVEL_OFF: 0
> - XFS_ERRLEVEL_LOW: 1
> - XFS_ERRLEVEL_HIGH: 5
> -
> - fs.xfs.panic_mask (Min: 0 Default: 0 Max: 256)
> - Causes certain error conditions to call BUG(). Value is a bitmask;
> - OR together the tags which represent errors which should cause panics:
> -
> - XFS_NO_PTAG 0
> - XFS_PTAG_IFLUSH 0x00000001
> - XFS_PTAG_LOGRES 0x00000002
> - XFS_PTAG_AILDELETE 0x00000004
> - XFS_PTAG_ERROR_REPORT 0x00000008
> - XFS_PTAG_SHUTDOWN_CORRUPT 0x00000010
> - XFS_PTAG_SHUTDOWN_IOERROR 0x00000020
> - XFS_PTAG_SHUTDOWN_LOGERROR 0x00000040
> - XFS_PTAG_FSBLOCK_ZERO 0x00000080
> - XFS_PTAG_VERIFIER_ERROR 0x00000100
> -
> - This option is intended for debugging only.
> -
> - fs.xfs.irix_symlink_mode (Min: 0 Default: 0 Max: 1)
> - Controls whether symlinks are created with mode 0777 (default)
> - or whether their mode is affected by the umask (irix mode).
> -
> - fs.xfs.irix_sgid_inherit (Min: 0 Default: 0 Max: 1)
> - Controls files created in SGID directories.
> - If the group ID of the new file does not match the effective group
> - ID or one of the supplementary group IDs of the parent dir, the
> - ISGID bit is cleared if the irix_sgid_inherit compatibility sysctl
> - is set.
> -
> - fs.xfs.inherit_sync (Min: 0 Default: 1 Max: 1)
> - Setting this to "1" will cause the "sync" flag set
> - by the xfs_io(8) chattr command on a directory to be
> - inherited by files in that directory.
> -
> - fs.xfs.inherit_nodump (Min: 0 Default: 1 Max: 1)
> - Setting this to "1" will cause the "nodump" flag set
> - by the xfs_io(8) chattr command on a directory to be
> - inherited by files in that directory.
> -
> - fs.xfs.inherit_noatime (Min: 0 Default: 1 Max: 1)
> - Setting this to "1" will cause the "noatime" flag set
> - by the xfs_io(8) chattr command on a directory to be
> - inherited by files in that directory.
> -
> - fs.xfs.inherit_nosymlinks (Min: 0 Default: 1 Max: 1)
> - Setting this to "1" will cause the "nosymlinks" flag set
> - by the xfs_io(8) chattr command on a directory to be
> - inherited by files in that directory.
> -
> - fs.xfs.inherit_nodefrag (Min: 0 Default: 1 Max: 1)
> - Setting this to "1" will cause the "nodefrag" flag set
> - by the xfs_io(8) chattr command on a directory to be
> - inherited by files in that directory.
> -
> - fs.xfs.rotorstep (Min: 1 Default: 1 Max: 256)
> - In "inode32" allocation mode, this option determines how many
> - files the allocator attempts to allocate in the same allocation
> - group before moving to the next allocation group. The intent
> - is to control the rate at which the allocator moves between
> - allocation groups when allocating extents for new files.
> -
> -Deprecated Sysctls
> -==================
> -
> -None at present.
> -
> -
> -Removed Sysctls
> -===============
> -
> - Name Removed
> - ---- -------
> - fs.xfs.xfsbufd_centisec v4.0
> - fs.xfs.age_buffer_centisecs v4.0
> -
> -
> -Error handling
> -==============
> -
> -XFS can act differently according to the type of error found during its
> -operation. The implementation introduces the following concepts to the error
> -handler:
> -
> - -failure speed:
> - Defines how fast XFS should propagate an error upwards when a specific
> - error is found during the filesystem operation. It can propagate
> - immediately, after a defined number of retries, after a set time period,
> - or simply retry forever.
> -
> - -error classes:
> - Specifies the subsystem the error configuration will apply to, such as
> - metadata IO or memory allocation. Different subsystems will have
> - different error handlers for which behaviour can be configured.
> -
> - -error handlers:
> - Defines the behavior for a specific error.
> -
> -The filesystem behavior during an error can be set via sysfs files. Each
> -error handler works independently - the first condition met by an error handler
> -for a specific class will cause the error to be propagated rather than reset and
> -retried.
> -
> -The action taken by the filesystem when the error is propagated is context
> -dependent - it may cause a shut down in the case of an unrecoverable error,
> -it may be reported back to userspace, or it may even be ignored because
> -there's nothing useful we can with the error or anyone we can report it to (e.g.
> -during unmount).
> -
> -The configuration files are organized into the following hierarchy for each
> -mounted filesystem:
> -
> - /sys/fs/xfs/<dev>/error/<class>/<error>/
> -
> -Where:
> - <dev>
> - The short device name of the mounted filesystem. This is the same device
> - name that shows up in XFS kernel error messages as "XFS(<dev>): ..."
> -
> - <class>
> - The subsystem the error configuration belongs to. As of 4.9, the defined
> - classes are:
> -
> - - "metadata": applies metadata buffer write IO
> -
> - <error>
> - The individual error handler configurations.
> -
> -
> -Each filesystem has "global" error configuration options defined in their top
> -level directory:
> -
> - /sys/fs/xfs/<dev>/error/
> -
> - fail_at_unmount (Min: 0 Default: 1 Max: 1)
> - Defines the filesystem error behavior at unmount time.
> -
> - If set to a value of 1, XFS will override all other error configurations
> - during unmount and replace them with "immediate fail" characteristics.
> - i.e. no retries, no retry timeout. This will always allow unmount to
> - succeed when there are persistent errors present.
> -
> - If set to 0, the configured retry behaviour will continue until all
> - retries and/or timeouts have been exhausted. This will delay unmount
> - completion when there are persistent errors, and it may prevent the
> - filesystem from ever unmounting fully in the case of "retry forever"
> - handler configurations.
> -
> - Note: there is no guarantee that fail_at_unmount can be set while an
> - unmount is in progress. It is possible that the sysfs entries are
> - removed by the unmounting filesystem before a "retry forever" error
> - handler configuration causes unmount to hang, and hence the filesystem
> - must be configured appropriately before unmount begins to prevent
> - unmount hangs.
> -
> -Each filesystem has specific error class handlers that define the error
> -propagation behaviour for specific errors. There is also a "default" error
> -handler defined, which defines the behaviour for all errors that don't have
> -specific handlers defined. Where multiple retry constraints are configuredi for
> -a single error, the first retry configuration that expires will cause the error
> -to be propagated. The handler configurations are found in the directory:
> -
> - /sys/fs/xfs/<dev>/error/<class>/<error>/
> -
> - max_retries (Min: -1 Default: Varies Max: INTMAX)
> - Defines the allowed number of retries of a specific error before
> - the filesystem will propagate the error. The retry count for a given
> - error context (e.g. a specific metadata buffer) is reset every time
> - there is a successful completion of the operation.
> -
> - Setting the value to "-1" will cause XFS to retry forever for this
> - specific error.
> -
> - Setting the value to "0" will cause XFS to fail immediately when the
> - specific error is reported.
> -
> - Setting the value to "N" (where 0 < N < Max) will make XFS retry the
> - operation "N" times before propagating the error.
> -
> - retry_timeout_seconds (Min: -1 Default: Varies Max: 1 day)
> - Define the amount of time (in seconds) that the filesystem is
> - allowed to retry its operations when the specific error is
> - found.
> -
> - Setting the value to "-1" will allow XFS to retry forever for this
> - specific error.
> -
> - Setting the value to "0" will cause XFS to fail immediately when the
> - specific error is reported.
> -
> - Setting the value to "N" (where 0 < N < Max) will allow XFS to retry the
> - operation for up to "N" seconds before propagating the error.
> -
> -Note: The default behaviour for a specific error handler is dependent on both
> -the class and error context. For example, the default values for
> -"metadata/ENODEV" are "0" rather than "-1" so that this error handler defaults
> -to "fail immediately" behaviour. This is done because ENODEV is a fatal,
> -unrecoverable error no matter how many times the metadata IO is retried.
> diff --git a/MAINTAINERS b/MAINTAINERS
> index d0ed73599..66e972e9a 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -17364,7 +17364,7 @@ L: linux-xfs@vger.kernel.org
> W: http://xfs.org/
> T: git git://git.kernel.org/pub/scm/fs/xfs/xfs-linux.git
> S: Supported
> -F: Documentation/filesystems/xfs.txt
> +F: Documentation/filesystems/xfs.rst
> F: fs/xfs/
>
> XILINX AXI ETHERNET DRIVER
> --
> 2.22.0
>