6d41807614
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>
89 lines
3.4 KiB
Plaintext
89 lines
3.4 KiB
Plaintext
config EXT3_FS
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tristate "Ext3 journalling file system support"
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select JBD
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help
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This is the journalling version of the Second extended file system
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(often called ext3), the de facto standard Linux file system
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(method to organize files on a storage device) for hard disks.
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The journalling code included in this driver means you do not have
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to run e2fsck (file system checker) on your file systems after a
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crash. The journal keeps track of any changes that were being made
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at the time the system crashed, and can ensure that your file system
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is consistent without the need for a lengthy check.
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Other than adding the journal to the file system, the on-disk format
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of ext3 is identical to ext2. It is possible to freely switch
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between using the ext3 driver and the ext2 driver, as long as the
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file system has been cleanly unmounted, or e2fsck is run on the file
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system.
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To add a journal on an existing ext2 file system or change the
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behavior of ext3 file systems, you can use the tune2fs utility ("man
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tune2fs"). To modify attributes of files and directories on ext3
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file systems, use chattr ("man chattr"). You need to be using
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e2fsprogs version 1.20 or later in order to create ext3 journals
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(available at <http://sourceforge.net/projects/e2fsprogs/>).
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To compile this file system support as a module, choose M here: the
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module will be called ext3.
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config EXT3_DEFAULTS_TO_ORDERED
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bool "Default to 'data=ordered' in ext3"
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depends on EXT3_FS
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help
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The journal mode options for ext3 have different tradeoffs
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between when data is guaranteed to be on disk and
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performance. The use of "data=writeback" can cause
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unwritten data to appear in files after an system crash or
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power failure, which can be a security issue. However,
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"data=ordered" mode can also result in major performance
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problems, including seconds-long delays before an fsync()
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call returns. For details, see:
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http://ext4.wiki.kernel.org/index.php/Ext3_data_mode_tradeoffs
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If you have been historically happy with ext3's performance,
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data=ordered mode will be a safe choice and you should
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answer 'y' here. If you understand the reliability and data
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privacy issues of data=writeback and are willing to make
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that trade off, answer 'n'.
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config EXT3_FS_XATTR
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bool "Ext3 extended attributes"
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depends on EXT3_FS
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default y
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help
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Extended attributes are name:value pairs associated with inodes by
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the kernel or by users (see the attr(5) manual page, or visit
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<http://acl.bestbits.at/> for details).
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If unsure, say N.
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You need this for POSIX ACL support on ext3.
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config EXT3_FS_POSIX_ACL
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bool "Ext3 POSIX Access Control Lists"
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depends on EXT3_FS_XATTR
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select FS_POSIX_ACL
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help
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Posix Access Control Lists (ACLs) support permissions for users and
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groups beyond the owner/group/world scheme.
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To learn more about Access Control Lists, visit the Posix ACLs for
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Linux website <http://acl.bestbits.at/>.
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If you don't know what Access Control Lists are, say N
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config EXT3_FS_SECURITY
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bool "Ext3 Security Labels"
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depends on EXT3_FS_XATTR
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help
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Security labels support alternative access control models
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implemented by security modules like SELinux. This option
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enables an extended attribute handler for file security
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labels in the ext3 filesystem.
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If you are not using a security module that requires using
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extended attributes for file security labels, say N.
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