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authorEric Sandeen <sandeen@redhat.com>2009-11-19 14:25:42 -0500
committerTheodore Ts'o <tytso@mit.edu>2009-11-19 14:25:42 -0500
commit5328e635315734d42080de9a5a1ee87bf4cae0a4 (patch)
tree4952c04c9b1faec9a3c82a3743805efad05ed96e /Documentation/filesystems/ext4.txt
parent2bba702d4f88d7b010ec37e2527b552588404ae7 (diff)
downloadlinux-5328e635315734d42080de9a5a1ee87bf4cae0a4.tar.gz
ext4: make trim/discard optional (and off by default)
It is anticipated that when sb_issue_discard starts doing
real work on trim-capable devices, we may see issues.  Make
this mount-time optional, and default it to off until we know
that things are working out OK.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'Documentation/filesystems/ext4.txt')
-rw-r--r--Documentation/filesystems/ext4.txt6
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index 6d94e0696f8c..26904ff6d61b 100644
--- a/Documentation/filesystems/ext4.txt
+++ b/Documentation/filesystems/ext4.txt
@@ -353,6 +353,12 @@ noauto_da_alloc		replacing existing files via patterns such as
 			system crashes before the delayed allocation
 			blocks are forced to disk.
 
+discard		Controls whether ext4 should issue discard/TRIM
+nodiscard(*)		commands to the underlying block device when
+			blocks are freed.  This is useful for SSD devices
+			and sparse/thinly-provisioned LUNs, but it is off
+			by default until sufficient testing has been done.
+
 Data Mode
 =========
 There are 3 different data modes: