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>
diff --git a/Documentation/filesystems/jfs.txt b/Documentation/filesystems/jfs.txt
index 26ebde7..2f94f9c 100644
--- a/Documentation/filesystems/jfs.txt
+++ b/Documentation/filesystems/jfs.txt
@@ -3,6 +3,7 @@
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
@@ -21,12 +22,12 @@
from backup media. The integrity of the volume is not
guaranteed if the system abnormally abends.
-integrity Default. Commit metadata changes to the journal. Use this
- option to remount a volume where the nointegrity option was
+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 Default. Remount the filesystem read-only on an 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
@@ -35,6 +36,18 @@
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.
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