diff options
author | Theodore Ts'o <tytso@mit.edu> | 2009-08-10 16:03:43 -0400 |
---|---|---|
committer | Jan Kara <jack@suse.cz> | 2009-08-24 10:48:32 -0400 |
commit | 6d41807614151829ae17a3a58bff8572af5e407e (patch) | |
tree | 8d507b9ed679e2a42f9e1c8f4e7ba5a958360ea2 /fs | |
parent | f4b9a988685da6386d7f9a72df3098bcc3270526 (diff) |
ext3: Update Kconfig description of EXT3_DEFAULTS_TO_ORDERED
The old description for this configuration option was perhaps not
completely balanced in terms of describing the tradeoffs of using a
default of data=writeback vs. data=ordered. Despite the fact that old
description very strongly recomended disabling this feature, all of
the major distributions have elected to preserve the existing 'legacy'
default, which is a strong hint that it perhaps wasn't telling the
whole story.
This revised description has been vetted by a number of ext3
developers as being better at informing the user about the tradeoffs
of enabling or disabling this configuration feature.
Cc: linux-ext4@vger.kernel.org
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/ext3/Kconfig | 32 |
1 files changed, 17 insertions, 15 deletions
diff --git a/fs/ext3/Kconfig b/fs/ext3/Kconfig index fb3c1a21b135..522b15498f45 100644 --- a/fs/ext3/Kconfig +++ b/fs/ext3/Kconfig | |||
@@ -29,23 +29,25 @@ config EXT3_FS | |||
29 | module will be called ext3. | 29 | module will be called ext3. |
30 | 30 | ||
31 | config EXT3_DEFAULTS_TO_ORDERED | 31 | config EXT3_DEFAULTS_TO_ORDERED |
32 | bool "Default to 'data=ordered' in ext3 (legacy option)" | 32 | bool "Default to 'data=ordered' in ext3" |
33 | depends on EXT3_FS | 33 | depends on EXT3_FS |
34 | help | 34 | help |
35 | If a filesystem does not explicitly specify a data ordering | 35 | The journal mode options for ext3 have different tradeoffs |
36 | mode, and the journal capability allowed it, ext3 used to | 36 | between when data is guaranteed to be on disk and |
37 | historically default to 'data=ordered'. | 37 | performance. The use of "data=writeback" can cause |
38 | 38 | unwritten data to appear in files after an system crash or | |
39 | That was a rather unfortunate choice, because it leads to all | 39 | power failure, which can be a security issue. However, |
40 | kinds of latency problems, and the 'data=writeback' mode is more | 40 | "data=ordered" mode can also result in major performance |
41 | appropriate these days. | 41 | problems, including seconds-long delays before an fsync() |
42 | 42 | call returns. For details, see: | |
43 | You should probably always answer 'n' here, and if you really | 43 | |
44 | want to use 'data=ordered' mode, set it in the filesystem itself | 44 | http://ext4.wiki.kernel.org/index.php/Ext3_data_mode_tradeoffs |
45 | with 'tune2fs -o journal_data_ordered'. | 45 | |
46 | 46 | If you have been historically happy with ext3's performance, | |
47 | But if you really want to enable the legacy default, you can do | 47 | data=ordered mode will be a safe choice and you should |
48 | so by answering 'y' to this question. | 48 | answer 'y' here. If you understand the reliability and data |
49 | privacy issues of data=writeback and are willing to make | ||
50 | that trade off, answer 'n'. | ||
49 | 51 | ||
50 | config EXT3_FS_XATTR | 52 | config EXT3_FS_XATTR |
51 | bool "Ext3 extended attributes" | 53 | bool "Ext3 extended attributes" |