The following patches reserve feature flags for e2fsprogs to avoid conflicts in the future.
1 - reserve a new INCOMPAT_INLINEDATA flag for storing small files in
the inode itself
2 - reserve a new INCOMPAT_LARGEDIR flag for allowing directories over
2GB in size and with an htree depth larger than 2 levels
Cheers, Andreas
--
Andreas Dilger
Principal Engineer
Whamcloud, Inc.
Reserve the EXT4_FEATURE_INCOMPAT_INLINEDATA feature flag for use
with storing small file data in the i_blocks field (up to 60 bytes)
and/or the large xattr space (after i_extra_isize, up to the large
inode size). On typical filesystems this can save 1-3% of the space,
and more importantly it also avoids seeking to read the data block.
This will become increasingly important with bigalloc filesystems,
since they consume a full cluster of blocks for each file, including
small directories that could easily fit into the inode itself.
Signed-off-by: Andreas Dilger <[email protected]>
Originally-by: Tao Ma <[email protected]>
---
lib/ext2fs/ext2_fs.h | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
index 0f8cde8..6cf47f9 100644
--- a/lib/ext2fs/ext2_fs.h
+++ b/lib/ext2fs/ext2_fs.h
@@ -719,6 +719,7 @@ struct ext2_super_block {
#define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200
#define EXT4_FEATURE_INCOMPAT_EA_INODE 0x0400
#define EXT4_FEATURE_INCOMPAT_DIRDATA 0x1000
+#define EXT4_FEATURE_INCOMPAT_INLINEDATA 0x2000 /* data in inode */
#define EXT2_FEATURE_COMPAT_SUPP 0
#define EXT2_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE| \
--
1.7.2
Reserve the EXT4_FEATURE_INCOMPAT_LARGEDIR feature flag for use by
directories larger than 2GB in size, or with more than 2-level htree.
This allows directories to exceed the following size limits:
best case typical case worst case
blocksize 8-byte name 64-byte name 255-byte name
========= ============ ============ =============
1024 768k entries 168k entries 36k entries
4096 50M entries 10.9M entries 2.9M entries
16384 3.2B entries 713M entries 195M entries
The 2GB size limit could be handled by an RO_COMPAT feature (as was
done with LARGE_FILE) since it only affects the use of i_size_high,
but the 2-level htree limit is hard coded into the kernel code by
the use of frame->at[2] allowing only 2 levels of index.
Since it is impossible that a directory larger than 2GB would be
created without a 3-level htree for blocksize 4096, a single
INCOMPAT flag is used for both of these cases.
Signed-off-by: Liang Zhen <[email protected]>
Signed-off-by: Andreas Dilger <[email protected]>
---
lib/ext2fs/ext2_fs.h | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
index 6cf47f9..154356a 100644
--- a/lib/ext2fs/ext2_fs.h
+++ b/lib/ext2fs/ext2_fs.h
@@ -720,6 +720,7 @@ struct ext2_super_block {
#define EXT4_FEATURE_INCOMPAT_EA_INODE 0x0400
#define EXT4_FEATURE_INCOMPAT_DIRDATA 0x1000
#define EXT4_FEATURE_INCOMPAT_INLINEDATA 0x2000 /* data in inode */
+#define EXT4_FEATURE_INCOMPAT_LARGEDIR 0x4000 /* >2GB or 3-lvl htree */
#define EXT2_FEATURE_COMPAT_SUPP 0
#define EXT2_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE| \
--
1.7.2
On Tue, Dec 06, 2011 at 05:13:51PM -0700, Andreas Dilger wrote:
> Reserve the EXT4_FEATURE_INCOMPAT_INLINEDATA feature flag for use
> with storing small file data in the i_blocks field (up to 60 bytes)
> and/or the large xattr space (after i_extra_isize, up to the large
> inode size). On typical filesystems this can save 1-3% of the space,
> and more importantly it also avoids seeking to read the data block.
>
> This will become increasingly important with bigalloc filesystems,
> since they consume a full cluster of blocks for each file, including
> small directories that could easily fit into the inode itself.
>
> Signed-off-by: Andreas Dilger <[email protected]>
> Originally-by: Tao Ma <[email protected]>
> ---
> lib/ext2fs/ext2_fs.h | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
> index 0f8cde8..6cf47f9 100644
> --- a/lib/ext2fs/ext2_fs.h
> +++ b/lib/ext2fs/ext2_fs.h
> @@ -719,6 +719,7 @@ struct ext2_super_block {
> #define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200
> #define EXT4_FEATURE_INCOMPAT_EA_INODE 0x0400
> #define EXT4_FEATURE_INCOMPAT_DIRDATA 0x1000
> +#define EXT4_FEATURE_INCOMPAT_INLINEDATA 0x2000 /* data in inode */
I was using 0x2000 for EXT4_FEATURE_INCOMPAT_BG_USE_META_CSUM, to change the
block group checksum to use crc32c.
--D
>
> #define EXT2_FEATURE_COMPAT_SUPP 0
> #define EXT2_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE| \
> --
> 1.7.2
>
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
On 12/07/2011 08:13 AM, Andreas Dilger wrote:
> Reserve the EXT4_FEATURE_INCOMPAT_INLINEDATA feature flag for use
> with storing small file data in the i_blocks field (up to 60 bytes)
> and/or the large xattr space (after i_extra_isize, up to the large
> inode size). On typical filesystems this can save 1-3% of the space,
> and more importantly it also avoids seeking to read the data block.
>
> This will become increasingly important with bigalloc filesystems,
> since they consume a full cluster of blocks for each file, including
> small directories that could easily fit into the inode itself.
>
> Signed-off-by: Andreas Dilger <[email protected]>
> Originally-by: Tao Ma <[email protected]>
I am fine with it. Thanks.
Tao
> ---
> lib/ext2fs/ext2_fs.h | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
> index 0f8cde8..6cf47f9 100644
> --- a/lib/ext2fs/ext2_fs.h
> +++ b/lib/ext2fs/ext2_fs.h
> @@ -719,6 +719,7 @@ struct ext2_super_block {
> #define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200
> #define EXT4_FEATURE_INCOMPAT_EA_INODE 0x0400
> #define EXT4_FEATURE_INCOMPAT_DIRDATA 0x1000
> +#define EXT4_FEATURE_INCOMPAT_INLINEDATA 0x2000 /* data in inode */
>
> #define EXT2_FEATURE_COMPAT_SUPP 0
> #define EXT2_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE| \
On 2011-12-06, at 5:39 PM, Darrick J. Wong wrote:
> On Tue, Dec 06, 2011 at 05:13:51PM -0700, Andreas Dilger wrote:
>> +#define EXT4_FEATURE_INCOMPAT_INLINEDATA 0x2000 /* data in inode */
>
> I was using 0x2000 for EXT4_FEATURE_INCOMPAT_BG_USE_META_CSUM, to change
> the block group checksum to use crc32c.
I didn't see that... I was looking at your patch and only noticed
EXT4_FEATURE_RO_COMPAT_METADATA_CSUM. I suspect your patch is closer
to landing it is better to use the 0x2000 value for BG_USE_META_CSUM,
and change the value for INLINEDATA to 0x8000 instead.
Cheers, Andreas
--
Andreas Dilger
Principal Engineer
Whamcloud, Inc.
On 12/07/2011 05:45 PM, Andreas Dilger wrote:
> On 2011-12-06, at 5:39 PM, Darrick J. Wong wrote:
>> On Tue, Dec 06, 2011 at 05:13:51PM -0700, Andreas Dilger wrote:
>>> +#define EXT4_FEATURE_INCOMPAT_INLINEDATA 0x2000 /* data in inode */
>>
>> I was using 0x2000 for EXT4_FEATURE_INCOMPAT_BG_USE_META_CSUM, to change
>> the block group checksum to use crc32c.
>
> I didn't see that... I was looking at your patch and only noticed
> EXT4_FEATURE_RO_COMPAT_METADATA_CSUM. I suspect your patch is closer
> to landing it is better to use the 0x2000 value for BG_USE_META_CSUM,
> and change the value for INLINEDATA to 0x8000 instead.
OK, I will use this number for inline data for the new version if there
is no objection.
Thanks
Tao