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9361401eb7
Make it possible to disable the block layer. Not all embedded devices require
it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require
the block layer to be present.
This patch does the following:
(*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev
support.
(*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls
an item that uses the block layer. This includes:
(*) Block I/O tracing.
(*) Disk partition code.
(*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS.
(*) The SCSI layer. As far as I can tell, even SCSI chardevs use the
block layer to do scheduling. Some drivers that use SCSI facilities -
such as USB storage - end up disabled indirectly from this.
(*) Various block-based device drivers, such as IDE and the old CDROM
drivers.
(*) MTD blockdev handling and FTL.
(*) JFFS - which uses set_bdev_super(), something it could avoid doing by
taking a leaf out of JFFS2's book.
(*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and
linux/elevator.h contingent on CONFIG_BLOCK being set. sector_div() is,
however, still used in places, and so is still available.
(*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and
parts of linux/fs.h.
(*) Makes a number of files in fs/ contingent on CONFIG_BLOCK.
(*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK.
(*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK
is not enabled.
(*) fs/no-block.c is created to hold out-of-line stubs and things that are
required when CONFIG_BLOCK is not set:
(*) Default blockdev file operations (to give error ENODEV on opening).
(*) Makes some /proc changes:
(*) /proc/devices does not list any blockdevs.
(*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK.
(*) Makes some compat ioctl handling contingent on CONFIG_BLOCK.
(*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if
given command other than Q_SYNC or if a special device is specified.
(*) In init/do_mounts.c, no reference is made to the blockdev routines if
CONFIG_BLOCK is not defined. This does not prohibit NFS roots or JFFS2.
(*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return
error ENOSYS by way of cond_syscall if so).
(*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if
CONFIG_BLOCK is not set, since they can't then happen.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
79 lines
3.1 KiB
Plaintext
79 lines
3.1 KiB
Plaintext
config XFS_FS
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tristate "XFS filesystem support"
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depends on BLOCK
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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_QUOTA
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bool "XFS Quota 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 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_SECURITY
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bool "XFS Security Label support"
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depends on XFS_FS
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help
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Security labels support alternative access control models
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implemented by security modules like SELinux. This option
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enables an extended attribute namespace for inode security
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labels in the XFS filesystem.
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If you are not using a security module that requires using
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extended attributes for inode security labels, say N.
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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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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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To learn more about Access Control Lists, visit the POSIX ACLs for
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Linux website <http://acl.bestbits.at/>.
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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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