mount: add info about ext{3,4} barriers to mount.8

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/mount/mount.8 b/mount/mount.8
index 3d451000a1178c7339808760ea4bc6d617e93fec..f4ef7e86ddcc49676d7c5ce449f0ae34ff545b40 100644 (file)
--- a/mount/mount.8
+++ b/mount/mount.8
@@ -1246,6 +1246,10 @@ internal file system integrity, however it can allow old data to appear
 in files after a crash and journal recovery.
 .RE
 .TP
+.BR barrier=0 " / "  barrier=1 "
+This enables/disables barriers.  barrier=0 disables it, barrier=1 enables it.
+The ext3 does not enable write barriers by default.
+.TP
 .BI commit= nrsec
 Sync all data and metadata every
 .I nrsec
@@ -1296,6 +1300,8 @@ penalty.  If your disks are battery-backed in one way or another, disabling
 barriers may safely improve performance.  The mount options "barrier" and
 "nobarrier" can also be used to enable or disable barriers, for consistency
 with other ext4 mount options.
+
+The ext4 enables write barriers by default.
 .TP
 .BI inode_readahead= n
 This tuning parameter controls the maximum number of inode table blocks that