From: Jose R. Santos <[email protected]>
FLEX_BG Kernel support.
This feature relaxes check restrictions on where each block groups meta data is
located within the storage media. This allows for the allocation of bitmaps or
inode tables outside the block group boundaries in cases where bad blocks forces
us to look for new blocks which the owning block group can not satisfy. This
will also allow for new meta-data allocation schemes to improve performance and
scalability.
Signed-off-by: Jose R. Santos <[email protected]>
--
fs/ext4/super.c | 7 +++++--
include/linux/ext4_fs.h | 4 +++-
2 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 4550b83..902e5c8 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1254,7 +1254,8 @@ static int ext4_check_descriptors (struct super_block * sb)
for (i = 0; i < sbi->s_groups_count; i++)
{
- if (i == sbi->s_groups_count - 1)
+ if (i == sbi->s_groups_count - 1 || EXT4_HAS_INCOMPAT_FEATURE(sb,
+ EXT4_FEATURE_INCOMPAT_FLEX_BG))
last_block = ext4_blocks_count(sbi->s_es) - 1;
else
last_block = first_block +
@@ -1291,7 +1292,9 @@ static int ext4_check_descriptors (struct super_block * sb)
i, inode_table);
return 0;
}
- first_block += EXT4_BLOCKS_PER_GROUP(sb);
+ if (!EXT4_HAS_INCOMPAT_FEATURE(sb,
+ EXT4_FEATURE_INCOMPAT_FLEX_BG))
+ first_block += EXT4_BLOCKS_PER_GROUP(sb);
gdp = (struct ext4_group_desc *)
((__u8 *)gdp + EXT4_DESC_SIZE(sb));
}
diff --git a/include/linux/ext4_fs.h b/include/linux/ext4_fs.h
index cdee7aa..d53e167 100644
--- a/include/linux/ext4_fs.h
+++ b/include/linux/ext4_fs.h
@@ -702,13 +702,15 @@ static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)
#define EXT4_FEATURE_INCOMPAT_META_BG 0x0010
#define EXT4_FEATURE_INCOMPAT_EXTENTS 0x0040 /* extents support */
#define EXT4_FEATURE_INCOMPAT_64BIT 0x0080
+#define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200
#define EXT4_FEATURE_COMPAT_SUPP EXT2_FEATURE_COMPAT_EXT_ATTR
#define EXT4_FEATURE_INCOMPAT_SUPP (EXT4_FEATURE_INCOMPAT_FILETYPE| \
EXT4_FEATURE_INCOMPAT_RECOVER| \
EXT4_FEATURE_INCOMPAT_META_BG| \
EXT4_FEATURE_INCOMPAT_EXTENTS| \
- EXT4_FEATURE_INCOMPAT_64BIT)
+ EXT4_FEATURE_INCOMPAT_64BIT| \
+ EXT4_FEATURE_INCOMPAT_FLEX_BG)
#define EXT4_FEATURE_RO_COMPAT_SUPP (EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER| \
EXT4_FEATURE_RO_COMPAT_LARGE_FILE| \
EXT4_FEATURE_RO_COMPAT_DIR_NLINK | \
On 9/10/07, Jose R. Santos <[email protected]> wrote:
> @@ -1254,7 +1254,8 @@ static int ext4_check_descriptors (struct super_block * sb)
>
> for (i = 0; i < sbi->s_groups_count; i++)
> {
> - if (i == sbi->s_groups_count - 1)
> + if (i == sbi->s_groups_count - 1 || EXT4_HAS_INCOMPAT_FEATURE(sb,
> + EXT4_FEATURE_INCOMPAT_FLEX_BG))
> last_block = ext4_blocks_count(sbi->s_es) - 1;
No need to check this featyre for every group, once at the beginning
of the function is enough.
On Tue, 11 Sep 2007 00:04:43 -0600
"Andreas Dilger" <[email protected]> wrote:
> On 9/10/07, Jose R. Santos <[email protected]> wrote:
> > @@ -1254,7 +1254,8 @@ static int ext4_check_descriptors (struct super_block * sb)
> >
> > for (i = 0; i < sbi->s_groups_count; i++)
> > {
> > - if (i == sbi->s_groups_count - 1)
> > + if (i == sbi->s_groups_count - 1 || EXT4_HAS_INCOMPAT_FEATURE(sb,
> > + EXT4_FEATURE_INCOMPAT_FLEX_BG))
> > last_block = ext4_blocks_count(sbi->s_es) - 1;
>
> No need to check this featyre for every group, once at the beginning
> of the function is enough.
>
Do you mean something like the original patch?
http://lists.openwall.net/linux-ext4/2007/07/12/20
Wouldn't we need to check all the descriptor for corruption if checksum
is not enable on the filesystem?
-JRS
On Sep 11, 2007 07:27 -0500, Jose R. Santos wrote:
> On Tue, 11 Sep 2007 00:04:43 -0600
> "Andreas Dilger" <[email protected]> wrote:
> > On 9/10/07, Jose R. Santos <[email protected]> wrote:
> > > @@ -1254,7 +1254,8 @@ static int ext4_check_descriptors (struct super_block * sb)
> > >
> > > for (i = 0; i < sbi->s_groups_count; i++)
> > > {
> > > - if (i == sbi->s_groups_count - 1)
> > > + if (i == sbi->s_groups_count - 1 || EXT4_HAS_INCOMPAT_FEATURE(sb,
> > > + EXT4_FEATURE_INCOMPAT_FLEX_BG))
> > > last_block = ext4_blocks_count(sbi->s_es) - 1;
> >
> > No need to check this featyre for every group, once at the beginning
> > of the function is enough.
> >
>
> Do you mean something like the original patch?
> http://lists.openwall.net/linux-ext4/2007/07/12/20
>
> Wouldn't we need to check all the descriptor for corruption if checksum
> is not enable on the filesystem?
Yes, I just meant you don't need to have:
EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
for each time through the loop. That loop is walked 8000 times per TB
at mount, so if we can make it faster we should do so.
Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.
On Tue, 11 Sep 2007 17:21:39 -0600
Andreas Dilger <[email protected]> wrote:
> On Sep 11, 2007 07:27 -0500, Jose R. Santos wrote:
> > On Tue, 11 Sep 2007 00:04:43 -0600
> > "Andreas Dilger" <[email protected]> wrote:
> > > On 9/10/07, Jose R. Santos <[email protected]> wrote:
> > > > @@ -1254,7 +1254,8 @@ static int ext4_check_descriptors (struct super_block * sb)
> > > >
> > > > for (i = 0; i < sbi->s_groups_count; i++)
> > > > {
> > > > - if (i == sbi->s_groups_count - 1)
> > > > + if (i == sbi->s_groups_count - 1 || EXT4_HAS_INCOMPAT_FEATURE(sb,
> > > > + EXT4_FEATURE_INCOMPAT_FLEX_BG))
> > > > last_block = ext4_blocks_count(sbi->s_es) - 1;
> > >
> > > No need to check this featyre for every group, once at the beginning
> > > of the function is enough.
> > >
> >
> > Do you mean something like the original patch?
> > http://lists.openwall.net/linux-ext4/2007/07/12/20
> >
> > Wouldn't we need to check all the descriptor for corruption if checksum
> > is not enable on the filesystem?
>
> Yes, I just meant you don't need to have:
>
> EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
>
> for each time through the loop. That loop is walked 8000 times per TB
> at mount, so if we can make it faster we should do so.
Good point, I'll send an updated patch.
-JRS