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Diffstat (limited to 'Documentation/filesystems/ext4.txt')
| -rw-r--r-- | Documentation/filesystems/ext4.txt | 23 |
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. |