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To reduce the runtime overhead even further when online fsck isn't running, use a static branch key to decide if we call wake_up on the drain. For compilers that support jump labels, the call to wake_up is replaced by a nop sled when nobody is waiting for intents to drain. From my initial microbenchmarking, every transition of the static key between the on and off states takes about 22000ns to complete; this is paid entirely by the xfs_scrub process. When the static key is off (which it should be when fsck isn't running), the nop sled adds an overhead of approximately 0.36ns to runtime code. The post-atomic lockless waiter check adds about 0.03ns, which is basically free. For the few compilers that don't support jump labels, runtime code pays the cost of calling wake_up on an empty waitqueue, which was observed to be about 30ns. However, most architectures that have sufficient memory and CPU capacity to run XFS also support jump labels, so this is not much of a worry. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
174 lines
6.4 KiB
Plaintext
174 lines
6.4 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0-only
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config XFS_FS
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tristate "XFS filesystem support"
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depends on BLOCK
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select EXPORTFS
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select LIBCRC32C
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select FS_IOMAP
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help
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XFS is a high performance journaling filesystem which originated
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on the SGI IRIX platform. It is completely multi-threaded, can
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support large files and large filesystems, extended attributes,
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variable block sizes, is extent based, and makes extensive use of
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Btrees (directories, extents, free space) to aid both performance
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and scalability.
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Refer to the documentation at <http://oss.sgi.com/projects/xfs/>
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for complete details. This implementation is on-disk compatible
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with the IRIX version of XFS.
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To compile this file system support as a module, choose M here: the
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module will be called xfs. Be aware, however, that if the file
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system of your root partition is compiled as a module, you'll need
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to use an initial ramdisk (initrd) to boot.
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config XFS_SUPPORT_V4
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bool "Support deprecated V4 (crc=0) format"
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depends on XFS_FS
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default y
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help
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The V4 filesystem format lacks certain features that are supported
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by the V5 format, such as metadata checksumming, strengthened
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metadata verification, and the ability to store timestamps past the
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year 2038. Because of this, the V4 format is deprecated. All users
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should upgrade by backing up their files, reformatting, and restoring
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from the backup.
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Administrators and users can detect a V4 filesystem by running
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xfs_info against a filesystem mountpoint and checking for a string
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beginning with "crc=". If the string "crc=0" is found, the
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filesystem is a V4 filesystem. If no such string is found, please
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upgrade xfsprogs to the latest version and try again.
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This option will become default N in September 2025. Support for the
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V4 format will be removed entirely in September 2030. Distributors
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can say N here to withdraw support earlier.
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To continue supporting the old V4 format (crc=0), say Y.
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To close off an attack surface, say N.
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config XFS_QUOTA
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bool "XFS Quota support"
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depends on XFS_FS
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select QUOTACTL
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help
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If you say Y here, you will be able to set limits for disk usage on
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a per user and/or a per group basis under XFS. XFS considers quota
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information as filesystem metadata and uses journaling to provide a
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higher level guarantee of consistency. The on-disk data format for
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quota is also compatible with the IRIX version of XFS, allowing a
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filesystem to be migrated between Linux and IRIX without any need
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for conversion.
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If unsure, say N. More comprehensive documentation can be found in
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README.quota in the xfsprogs package. XFS quota can be used either
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with or without the generic quota support enabled (CONFIG_QUOTA) -
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they are completely independent subsystems.
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config XFS_POSIX_ACL
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bool "XFS POSIX ACL support"
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depends on XFS_FS
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select FS_POSIX_ACL
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help
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POSIX Access Control Lists (ACLs) support permissions for users and
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groups beyond the owner/group/world scheme.
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If you don't know what Access Control Lists are, say N.
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config XFS_RT
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bool "XFS Realtime subvolume support"
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depends on XFS_FS
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help
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If you say Y here you will be able to mount and use XFS filesystems
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which contain a realtime subvolume. The realtime subvolume is a
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separate area of disk space where only file data is stored. It was
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originally designed to provide deterministic data rates suitable
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for media streaming applications, but is also useful as a generic
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mechanism for ensuring data and metadata/log I/Os are completely
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separated. Regular file I/Os are isolated to a separate device
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from all other requests, and this can be done quite transparently
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to applications via the inherit-realtime directory inode flag.
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See the xfs man page in section 5 for additional information.
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If unsure, say N.
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config XFS_DRAIN_INTENTS
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bool
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select JUMP_LABEL if HAVE_ARCH_JUMP_LABEL
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config XFS_ONLINE_SCRUB
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bool "XFS online metadata check support"
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default n
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depends on XFS_FS
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select XFS_DRAIN_INTENTS
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help
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If you say Y here you will be able to check metadata on a
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mounted XFS filesystem. This feature is intended to reduce
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filesystem downtime by supplementing xfs_repair. The key
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advantage here is to look for problems proactively so that
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they can be dealt with in a controlled manner.
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This feature is considered EXPERIMENTAL. Use with caution!
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See the xfs_scrub man page in section 8 for additional information.
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If unsure, say N.
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config XFS_ONLINE_REPAIR
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bool "XFS online metadata repair support"
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default n
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depends on XFS_FS && XFS_ONLINE_SCRUB
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help
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If you say Y here you will be able to repair metadata on a
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mounted XFS filesystem. This feature is intended to reduce
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filesystem downtime by fixing minor problems before they cause the
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filesystem to go down. However, it requires that the filesystem be
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formatted with secondary metadata, such as reverse mappings and inode
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parent pointers.
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This feature is considered EXPERIMENTAL. Use with caution!
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See the xfs_scrub man page in section 8 for additional information.
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If unsure, say N.
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config XFS_WARN
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bool "XFS Verbose Warnings"
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depends on XFS_FS && !XFS_DEBUG
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help
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Say Y here to get an XFS build with many additional warnings.
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It converts ASSERT checks to WARN, so will log any out-of-bounds
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conditions that occur that would otherwise be missed. It is much
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lighter weight than XFS_DEBUG and does not modify algorithms and will
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not cause the kernel to panic on non-fatal errors.
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However, similar to XFS_DEBUG, it is only advisable to use this if you
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are debugging a particular problem.
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config XFS_DEBUG
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bool "XFS Debugging support"
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depends on XFS_FS
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help
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Say Y here to get an XFS build with many debugging features,
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including ASSERT checks, function wrappers around macros,
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and extra sanity-checking functions in various code paths.
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Note that the resulting code will be HUGE and SLOW, and probably
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not useful unless you are debugging a particular problem.
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Say N unless you are an XFS developer, or you play one on TV.
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config XFS_ASSERT_FATAL
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bool "XFS fatal asserts"
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default y
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depends on XFS_FS && XFS_DEBUG
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help
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Set the default DEBUG mode ASSERT failure behavior.
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Say Y here to cause DEBUG mode ASSERT failures to result in fatal
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errors that BUG() the kernel by default. If you say N, ASSERT failures
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result in warnings.
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This behavior can be modified at runtime via sysfs.
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