linux/Documentation/filesystems/jfs.txt
Tino Reichardt b40c2e665c fs/jfs: TRIM support for JFS Filesystem
This patch adds support for the two linux interfaces of the discard/TRIM
command for SSD devices and sparse/thinly-provisioned LUNs.

JFS will support batched discard via FITRIM ioctl and online discard
with the discard mount option.

Signed-off-by: Tino Reichardt <list-jfs@mcmilk.de>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
2012-09-17 11:58:19 -05:00

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IBM's Journaled File System (JFS) for Linux
JFS Homepage: http://jfs.sourceforge.net/
The following mount options are supported:
(*) == default
iocharset=name Character set to use for converting from Unicode to
ASCII. The default is to do no conversion. Use
iocharset=utf8 for UTF-8 translations. This requires
CONFIG_NLS_UTF8 to be set in the kernel .config file.
iocharset=none specifies the default behavior explicitly.
resize=value Resize the volume to <value> blocks. JFS only supports
growing a volume, not shrinking it. This option is only
valid during a remount, when the volume is mounted
read-write. The resize keyword with no value will grow
the volume to the full size of the partition.
nointegrity Do not write to the journal. The primary use of this option
is to allow for higher performance when restoring a volume
from backup media. The integrity of the volume is not
guaranteed if the system abnormally abends.
integrity(*) Commit metadata changes to the journal. Use this option to
remount a volume where the nointegrity option was
previously specified in order to restore normal behavior.
errors=continue Keep going on a filesystem error.
errors=remount-ro(*) Remount the filesystem read-only on an error.
errors=panic Panic and halt the machine if an error occurs.
uid=value Override on-disk uid with specified value
gid=value Override on-disk gid with specified value
umask=value Override on-disk umask with specified octal value. For
directories, the execute bit will be set if the corresponding
read bit is set.
discard=minlen This enables/disables the use of discard/TRIM commands.
discard The discard/TRIM commands are sent to the underlying
nodiscard(*) block device when blocks are freed. This is useful for SSD
devices and sparse/thinly-provisioned LUNs. The FITRIM ioctl
command is also available together with the nodiscard option.
The value of minlen specifies the minimum blockcount, when
a TRIM command to the block device is considered usefull.
When no value is given to the discard option, it defaults to
64 blocks, which means 256KiB in JFS.
The minlen value of discard overrides the minlen value given
on an FITRIM ioctl().
Please send bugs, comments, cards and letters to shaggy@linux.vnet.ibm.com.
The JFS mailing list can be subscribed to by using the link labeled
"Mail list Subscribe" at our web page http://jfs.sourceforge.net/