block: enable by default support for large devices and files on 32-bit archs
Enable by default support for large devices and files (CONFIG_LBD):
- With 1TB disks being a commodity hardware it is quite easy to hit 2TB
limitation while building RAIDs etc. and many distros have been using
CONFIG_LBD=y by default already (at least Fedora 10 and openSUSE 11.1).
- This should also prevent a subtle ext4 filesystem compatibility issue:
mke2fs.ext4 defaults to creating filesystems with huge_files feature
enabled and such filesystems cannot be later mounted read-write on
machines with CONFIG_LBD=n (it should be quite easy to hit this issue
when trying to use filesystem created using distro kernel on system
running the self-build kernel, think about USB disk enclosures & co.).
While at it:
- Clarify config option help text w.r.t. mounting ext4 filesystems
(they can be mounted with CONFIG_LBD=n but in the read-only mode).
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/Kconfig b/block/Kconfig
index e7d1278..2c39527 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -26,6 +26,7 @@
config LBD
bool "Support for large block devices and files"
depends on !64BIT
+ default y
help
Enable block devices or files of size 2TB and larger.
@@ -38,11 +39,13 @@
The ext4 filesystem requires that this feature be enabled in
order to support filesystems that have the huge_file feature
- enabled. Otherwise, it will refuse to mount any filesystems
- that use the huge_file feature, which is enabled by default
- by mke2fs.ext4. The GFS2 filesystem also requires this feature.
+ enabled. Otherwise, it will refuse to mount in the read-write
+ mode any filesystems that use the huge_file feature, which is
+ enabled by default by mke2fs.ext4.
- If unsure, say N.
+ The GFS2 filesystem also requires this feature.
+
+ If unsure, say Y.
config BLK_DEV_BSG
bool "Block layer SG support v4 (EXPERIMENTAL)"