Signed-off-by: "Theodore Ts'o" <[email protected]>
Cc: Jens Axboe <[email protected]>
---
block/Kconfig | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/block/Kconfig b/block/Kconfig
index 1ab7c15..e10f4c1 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -64,6 +64,12 @@ config LSF
Say Y here if you want to be able to handle very large files (2TB
and larger), otherwise say N.
+ 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.
+
If unsure, say Y.
config BLK_DEV_BSG
--
1.6.0.4.8.g36f27.dirty
I had to use a slightly different patch for 2.6.28-git7...
block: Add Kconfig help which notes that ext4 needs CONFIG_LBD
Signed-off-by: "Theodore Ts'o" <[email protected]>
Cc: Jens Axboe <[email protected]>
diff --git a/block/Kconfig b/block/Kconfig
index ac0956f..0cbb3b8 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -36,6 +36,12 @@ config LBD
This option also enables support for single files larger than
2TB.
+ 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.
+
If unsure, say N.
config BLK_DEV_IO_TRACE
On Jan 06, 2009 12:21 -0500, Theodore Ts'o wrote:
> @@ -64,6 +64,12 @@ config LSF
> + 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.
Wouldn't it make sense to just enable this by default if ext4 is enabled?
On a related note, I wonder if we need to re-examine the use of the COMPAT
flags in ext4. We went from a usage of "kernel enables flag when feature
is used" (e.g. LARGE_FILE) to "admin must set flag in order to use feature"
(e.g HUGE_FILE).
The former system was recording the state of currently-used features in the
filesystem, and maximized portability of the filesystem if the feature
was NOT used. The newer system makes a filesystem somewhat less portable
even if the feature is not being used at all (e.g. files > 2TB in size).
I wonder if we should split the s_feature_*compat fields in the superblock
to "present feature" and "allowed feature" so that e.g. HUGE_FILE count
be put into "allowed feature" and would only appear in "present feature"
if a file > 2TB in size arrives. That ensures the filesystem remains
maximally compatible, while allowing the admin to select which features
are permissible.
Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.
On Thu, Jan 08 2009, Andreas Dilger wrote:
> On Jan 06, 2009 12:21 -0500, Theodore Ts'o wrote:
> > @@ -64,6 +64,12 @@ config LSF
> > + 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.
>
> Wouldn't it make sense to just enable this by default if ext4 is enabled?
Agree, since it'll prevent the fs from mounting, using a select makes a
lot more sense.
--
Jens Axboe