mount: remove extN from mount.8 man page
The e2fsprogs package contains ext4(5) man page with all necessary information. We do not have to duplicate effort and maintain copy of the extN mount options in our mount.8. (We already do the same for XFS.) Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
Karel Zak
parent
dda4743b45
commit
c5f7549097
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@ -1550,354 +1550,8 @@ starting with 2.6.29. Further, this option is valid only if
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CONFIG_DEVPTS_MULTIPLE_INSTANCES is enabled in the kernel
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configuration.
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.SS "Mount options for ext2"
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The `ext2' filesystem is the standard Linux filesystem.
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For most mount options the default
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is determined by the filesystem superblock. Set them with
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.BR tune2fs (8).
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.TP
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.BR acl | noacl
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Support POSIX Access Control Lists (or not).
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.\" requires CONFIG_EXT2_FS_POSIX_ACL
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.TP
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.BR bsddf | minixdf
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Set the behavior for the
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.I statfs
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system call. The
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.B minixdf
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behavior is to return in the
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.I f_blocks
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field the total number of blocks of the filesystem, while the
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.B bsddf
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behavior (which is the default) is to subtract the overhead blocks
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used by the ext2 filesystem and not available for file storage. Thus
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.sp 1
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% mount /k \-o minixdf; df /k; umount /k
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.TS
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tab(#);
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l2 l2 r2 l2 l2 l
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l c r c c l.
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Filesystem#1024-blocks#Used#Available#Capacity#Mounted on
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/dev/sda6#2630655#86954#2412169#3%#/k
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.TE
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.sp 1
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% mount /k \-o bsddf; df /k; umount /k
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.TS
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tab(#);
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l2 l2 r2 l2 l2 l
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l c r c c l.
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Filesystem#1024-blocks#Used#Available#Capacity#Mounted on
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/dev/sda6#2543714#13#2412169#0%#/k
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.TE
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.sp 1
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(Note that this example shows that one can add command-line options
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to the options given in
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.IR /etc/fstab .)
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.TP
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.BR check=none " or " nocheck
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No checking is done at mount time. This is the default. This is fast.
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It is wise to invoke
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.BR e2fsck (8)
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every now and then, e.g.\& at boot time. The non-default behavior is unsupported
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(check=normal and check=strict options have been removed). Note that these mount options
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don't have to be supported if ext4 kernel driver is used for ext2 and ext3 filesystems.
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.TP
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.B debug
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Print debugging info upon each (re)mount.
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.TP
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.BR errors= { continue | remount-ro | panic }
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Define the behavior when an error is encountered.
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(Either ignore errors and just mark the filesystem erroneous and continue,
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or remount the filesystem read-only, or panic and halt the system.)
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The default is set in the filesystem superblock, and can be
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changed using
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.BR tune2fs (8).
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.TP
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.BR grpid | bsdgroups " and " nogrpid | sysvgroups
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These options define what group ID a newly created file gets.
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When
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.B grpid
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is set, it takes the group ID of the directory in which it is created;
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otherwise (the default) it takes the fsgid of the current process, unless
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the directory has the set-group-ID bit set, in which case it takes the GID
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from the parent directory, and also gets the set-group-ID bit set
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if it is a directory itself.
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.TP
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.BR grpquota | noquota | quota | usrquota
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The usrquota (same as quota) mount option enables user quota support on the
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filesystem. grpquota enables group quotas support. You need the quota utilities
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to actually enable and manage the quota system.
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.TP
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.B nouid32
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Disables 32-bit UIDs and GIDs. This is for interoperability with older
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kernels which only store and expect 16-bit values.
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.TP
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.BR oldalloc " or " orlov
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Use old allocator or Orlov allocator for new inodes. Orlov is default.
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.TP
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\fBresgid=\fP\,\fIn\fP and \fBresuid=\fP\,\fIn\fP
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The ext2 filesystem reserves a certain percentage of the available
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space (by default 5%, see
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.BR mke2fs (8)
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and
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.BR tune2fs (8)).
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These options determine who can use the reserved blocks.
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(Roughly: whoever has the specified UID, or belongs to the specified group.)
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.TP
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.BI sb= n
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Instead of block 1, use block
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.I n
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as superblock. This could be useful when the filesystem has been damaged.
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See
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.B dumpe2fs /dev/foo | grep superblock
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to list alternatively usable superblocks.
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.TP
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.BR user_xattr | nouser_xattr
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Support "user." extended attributes (or not).
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.\" requires CONFIG_EXT2_FS_XATTR
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.SS "Mount options for ext3"
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The ext3 filesystem is a version of the ext2 filesystem which has been
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enhanced with journaling. It supports the same options as ext2 as
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well as the following additions:
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.\" .TP
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.\" .BR abort
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.\" Mount the filesystem in abort mode, as if a fatal error has occurred.
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.TP
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.B journal=update
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Update the ext3 filesystem's journal to the current format.
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.TP
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.B journal=inum
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When a journal already exists, this option is ignored. Otherwise, it
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specifies the number of the inode which will represent the ext3 filesystem's
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journal file; ext3 will create a new journal, overwriting the old contents
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of the file whose inode number is
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.IR inum .
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.TP
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.BR journal_dev=devnum / journal_path=path
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When the external journal device's major/minor numbers
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have changed, these options allow the user to specify
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the new journal location. The journal device is
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identified either through its new major/minor numbers encoded
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in devnum, or via a path to the device.
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.TP
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.BR norecovery / noload
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Don't load the journal on mounting. Note that
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if the filesystem was not unmounted cleanly,
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skipping the journal replay will lead to the
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filesystem containing inconsistencies that can
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lead to any number of problems.
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.TP
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.BR data= { journal | ordered | writeback }
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Specifies the journaling mode for file data. Metadata is always journaled.
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To use modes other than
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.B ordered
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on the root filesystem, pass the mode to the kernel as boot parameter, e.g.\&
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.IR rootflags=data=journal .
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.RS
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.TP
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.B journal
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All data is committed into the journal prior to being written into the
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main filesystem.
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.TP
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.B ordered
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This is the default mode. All data is forced directly out to the main file
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system prior to its metadata being committed to the journal.
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.TP
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.B writeback
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Data ordering is not preserved \(en data may be written into the main
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filesystem after its metadata has been committed to the journal.
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This is rumoured to be the highest-throughput option. It guarantees
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internal filesystem integrity, however it can allow old data to appear
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in files after a crash and journal recovery.
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.RE
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.TP
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.B data_err=ignore
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Just print an error message if an error occurs in a file data buffer in
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ordered mode.
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.TP
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.B data_err=abort
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Abort the journal if an error occurs in a file data buffer in ordered mode.
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.TP
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.BR barrier=0 " / " barrier=1 "
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This disables / enables the use of write barriers in the jbd code. barrier=0
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disables, barrier=1 enables (default). This also requires an IO stack which can
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support barriers, and if jbd gets an error on a barrier write, it will disable
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barriers again with a warning. Write barriers enforce proper on-disk ordering
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of journal commits, making volatile disk write caches safe to use, at some
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performance penalty. If your disks are battery-backed in one way or another,
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disabling barriers may safely improve performance.
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.TP
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.BI commit= nrsec
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Sync all data and metadata every
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.I nrsec
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seconds. The default value is 5 seconds. Zero means default.
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.TP
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.B user_xattr
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Enable Extended User Attributes. See the
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.BR attr (5)
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manual page.
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.TP
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.B acl
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Enable POSIX Access Control Lists. See the
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.BR acl (5)
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manual page.
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.TP
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.BR usrjquota=aquota.user | grpjquota=aquota.group | jqfmt=vfsv0
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Apart from the old quota system (as in ext2, jqfmt=vfsold aka version 1 quota)
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ext3 also supports journaled quotas (version 2 quota). jqfmt=vfsv0
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enables journaled quotas. For journaled quotas the mount options
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usrjquota=aquota.user and grpjquota=aquota.group are required to tell the
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quota system which quota database files to use. Journaled quotas have the
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advantage that even after a crash no quota check is required.
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.SS "Mount options for ext4"
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The ext4 filesystem is an advanced level of the ext3 filesystem which
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incorporates scalability and reliability enhancements for supporting large
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filesystem.
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The options
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.B journal_dev, norecovery, noload, data, commit, orlov, oldalloc, [no]user_xattr
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.B [no]acl, bsddf, minixdf, debug, errors, data_err, grpid, bsdgroups, nogrpid
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.B sysvgroups, resgid, resuid, sb, quota, noquota, grpquota, usrquota
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.B usrjquota, grpjquota and jqfmt
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are backwardly compatible with ext3 or ext2.
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.TP
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.B journal_checksum
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Enable checksumming of the journal transactions. This will allow the recovery
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code in e2fsck and the kernel to detect corruption in the kernel. It is a
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compatible change and will be ignored by older kernels.
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.TP
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.B journal_async_commit
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Commit block can be written to disk without waiting for descriptor blocks.
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If enabled, older kernels cannot mount the device.
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This will enable 'journal_checksum' internally.
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.TP
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.BR barrier=0 " / " barrier=1 " / " barrier " / " nobarrier
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These mount options have the same effect as in ext3. The mount options
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"barrier" and "nobarrier" are added for consistency with other ext4 mount
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options.
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The ext4 filesystem enables write barriers by default.
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.TP
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.BI inode_readahead_blks= n
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This tuning parameter controls the maximum number of inode table blocks that
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ext4's inode table readahead algorithm will pre-read into the buffer cache.
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The value must be a power of 2. The default value is 32 blocks.
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.TP
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.BI stripe= n
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Number of filesystem blocks that mballoc will try to use for allocation size
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and alignment. For RAID5/6 systems this should be the number of data disks *
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RAID chunk size in filesystem blocks.
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.TP
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.B delalloc
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Deferring block allocation until write-out time.
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.TP
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.B nodelalloc
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Disable delayed allocation. Blocks are allocated when data is copied from user
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to page cache.
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.TP
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.BI max_batch_time= usec
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Maximum amount of time ext4 should wait for additional filesystem operations to
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be batch together with a synchronous write operation. Since a synchronous
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write operation is going to force a commit and then a wait for the I/O
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complete, it doesn't cost much, and can be a huge throughput win, we wait for a
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small amount of time to see if any other transactions can piggyback on the
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synchronous write. The algorithm used is designed to automatically tune for
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the speed of the disk, by measuring the amount of time (on average) that it
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takes to finish committing a transaction. Call this time the "commit time".
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If the time that the transaction has been running is less than the commit time,
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ext4 will try sleeping for the commit time to see if other operations will join
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the transaction. The commit time is capped by the max_batch_time, which
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defaults to 15000\ \[mc]s (15\ ms). This optimization can be turned off entirely by
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setting max_batch_time to 0.
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.TP
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.BI min_batch_time= usec
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This parameter sets the commit time (as described above) to be at least
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min_batch_time. It defaults to zero microseconds. Increasing this parameter
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may improve the throughput of multi-threaded, synchronous workloads on very
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fast disks, at the cost of increasing latency.
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.TP
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.BI journal_ioprio= prio
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The I/O priority (from 0 to 7, where 0 is the highest priority) which should be
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used for I/O operations submitted by kjournald2 during a commit operation.
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This defaults to 3, which is a slightly higher priority than the default I/O
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priority.
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.TP
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.B abort
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Simulate the effects of calling ext4_abort() for
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debugging purposes. This is normally used while
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remounting a filesystem which is already mounted.
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.TP
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.BR auto_da_alloc | noauto_da_alloc
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Many broken applications don't use fsync() when
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replacing existing files via patterns such as
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fd = open("foo.new")/write(fd,...)/close(fd)/ rename("foo.new", "foo")
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or worse yet
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fd = open("foo", O_TRUNC)/write(fd,...)/close(fd).
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If auto_da_alloc is enabled, ext4 will detect the replace-via-rename and
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replace-via-truncate patterns and force that any delayed allocation blocks are
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allocated such that at the next journal commit, in the default data=ordered
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mode, the data blocks of the new file are forced to disk before the rename()
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operation is committed. This provides roughly the same level of guarantees as
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ext3, and avoids the "zero-length" problem that can happen when a system
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crashes before the delayed allocation blocks are forced to disk.
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.TP
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.B noinit_itable
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Do not initialize any uninitialized inode table blocks in the background. This
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feature may be used by installation CD's so that the install process can
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complete as quickly as possible; the inode table initialization process would
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then be deferred until the next time the filesystem is mounted.
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.TP
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.B init_itable=n
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The lazy itable init code will wait n times the number of milliseconds it took
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to zero out the previous block group's inode table. This minimizes the impact on
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system performance while the filesystem's inode table is being initialized.
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.TP
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.BR discard / nodiscard
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Controls whether ext4 should issue discard/TRIM commands to the underlying
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block device when blocks are freed. This is useful for SSD devices and
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sparse/thinly-provisioned LUNs, but it is off by default until sufficient
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testing has been done.
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.TP
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.B nouid32
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Disables 32-bit UIDs and GIDs. This is for
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interoperability with older kernels which only
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store and expect 16-bit values.
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.TP
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.BR block_validity / noblock_validity
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This options allows to enables/disables the in-kernel facility for tracking
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filesystem metadata blocks within internal data structures. This allows multi-\c
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block allocator and other routines to quickly locate extents which might
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overlap with filesystem metadata blocks. This option is intended for debugging
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purposes and since it negatively affects the performance, it is off by default.
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.TP
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.BR dioread_lock / dioread_nolock
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Controls whether or not ext4 should use the DIO read locking. If the
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dioread_nolock option is specified ext4 will allocate uninitialized extent
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before buffer write and convert the extent to initialized after IO completes.
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This approach allows ext4 code to avoid using inode mutex, which improves
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scalability on high speed storages. However this does not work with data
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journaling and dioread_nolock option will be ignored with kernel warning.
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Note that dioread_nolock code path is only used for extent-based files.
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Because of the restrictions this options comprises it is off by default
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(e.g.\& dioread_lock).
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.TP
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.B max_dir_size_kb=n
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This limits the size of the directories so that any attempt to expand them
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beyond the specified limit in kilobytes will cause an ENOSPC error. This is
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useful in memory-constrained environments, where a very large directory can
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cause severe performance problems or even provoke the Out Of Memory killer. (For
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example, if there is only 512\ MB memory available, a 176\ MB directory may
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seriously cramp the system's style.)
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.TP
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.B i_version
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Enable 64-bit inode version support. This option is off by default.
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.SS "Mount options for ext2, ext3 and ext4"
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See the options section of the ext2(5), ext3(5) or ext4(5) man page (the e2fsprogs package must be installed).
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.SS "Mount options for fat"
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(Note:
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