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-rw-r--r--Documentation/filesystems/ext4.txt23
1 files changed, 7 insertions, 16 deletions
diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index 3ae9bc94352a..232a575a0c48 100644
--- a/Documentation/filesystems/ext4.txt
+++ b/Documentation/filesystems/ext4.txt
@@ -68,12 +68,12 @@ Note: More extensive information for getting started with ext4 can be
'-o barriers=[0|1]' mount option for both ext3 and ext4 filesystems
for a fair comparison. When tuning ext3 for best benchmark numbers,
it is often worthwhile to try changing the data journaling mode; '-o
- data=writeback,nobh' can be faster for some workloads. (Note
- however that running mounted with data=writeback can potentially
- leave stale data exposed in recently written files in case of an
- unclean shutdown, which could be a security exposure in some
- situations.) Configuring the filesystem with a large journal can
- also be helpful for metadata-intensive workloads.
+ data=writeback' can be faster for some workloads. (Note however that
+ running mounted with data=writeback can potentially leave stale data
+ exposed in recently written files in case of an unclean shutdown,
+ which could be a security exposure in some situations.) Configuring
+ the filesystem with a large journal can also be helpful for
+ metadata-intensive workloads.
2. Features
===========
@@ -272,14 +272,6 @@ grpjquota=<file> during journal replay. They replace the above
package for more details
(http://sourceforge.net/projects/linuxquota).
-bh (*) ext4 associates buffer heads to data pages to
-nobh (a) cache disk block mapping information
- (b) link pages into transaction to provide
- ordering guarantees.
- "bh" option forces use of buffer heads.
- "nobh" option tries to avoid associating buffer
- heads (supported only for "writeback" mode).
-
stripe=n Number of filesystem blocks that mballoc will try
to use for allocation size and alignment. For RAID5/6
systems this should be the number of data
@@ -393,8 +385,7 @@ dioread_nolock locking. If the dioread_nolock option is specified
write and convert the extent to initialized after IO
completes. This approach allows ext4 code to avoid
using inode mutex, which improves scalability on high
- speed storages. However this does not work with nobh
- option and the mount will fail. Nor does it work with
+ speed storages. However this does not work with
data journaling and dioread_nolock option will be
ignored with kernel warning. Note that dioread_nolock
code path is only used for extent-based files.