In filesystems with the meta block group flag on, ext3_bg_num_gdb()
fails to report the correct number of blocks used to store the group
descriptor backups in a given group. It happens because meta_bg
follows a different logic from the original ext3 backup placement
in groups multiples of 3, 5 and 7.
Signed-off-by: Glauber de Oliveira Costa <[email protected]>
---
fs/ext3/balloc.c | 33 +++++++++++++++++++++++++++++----
1 files changed, 29 insertions(+), 4 deletions(-)
1164cfd9b1b413f6c4b86bac11006ba2b933ccb1
diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c
index 6250fcd..8bf87b0 100644
--- a/fs/ext3/balloc.c
+++ b/fs/ext3/balloc.c
@@ -1499,6 +1499,25 @@ int ext3_bg_has_super(struct super_block
return 1;
}
+static unsigned long ext3_bg_num_gdb_meta(struct super_block *sb, int group)
+{
+ unsigned long metagroup = group / EXT3_DESC_PER_BLOCK(sb);
+ unsigned long first = metagroup * EXT3_DESC_PER_BLOCK(sb);
+ unsigned long last = first + EXT3_DESC_PER_BLOCK(sb) - 1;
+
+ if (group == first || group == first + 1 || group == last)
+ return 1;
+ return 0;
+}
+
+static unsigned long ext3_bg_num_gdb_nometa(struct super_block *sb, int group)
+{
+ if (EXT3_HAS_RO_COMPAT_FEATURE(sb,EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)&&
+ !ext3_group_sparse(group))
+ return 0;
+ return EXT3_SB(sb)->s_gdb_count;
+}
+
/**
* ext3_bg_num_gdb - number of blocks used by the group table in group
* @sb: superblock for filesystem
@@ -1510,9 +1529,15 @@ int ext3_bg_has_super(struct super_block
*/
unsigned long ext3_bg_num_gdb(struct super_block *sb, int group)
{
- if (EXT3_HAS_RO_COMPAT_FEATURE(sb,EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)&&
- !ext3_group_sparse(group))
- return 0;
- return EXT3_SB(sb)->s_gdb_count;
+ unsigned long first_meta_bg =
+ cpu_to_le32(EXT3_SB(sb)->s_es->s_first_meta_bg);
+ unsigned long metagroup = group / EXT3_DESC_PER_BLOCK(sb);
+
+ if (!EXT3_HAS_INCOMPAT_FEATURE(sb,EXT3_FEATURE_INCOMPAT_META_BG)
+ || metagroup < first_meta_bg)
+ return ext3_bg_num_gdb_nometa(sb,group);
+
+ return ext3_bg_num_gdb_meta(sb,group);
+
}
--
1.0.4
On Fri, Jan 20, 2006 at 06:37:21PM +0000, Glauber de Oliveira Costa wrote:
> In filesystems with the meta block group flag on, ext3_bg_num_gdb()
> fails to report the correct number of blocks used to store the group
> descriptor backups in a given group. It happens because meta_bg
> follows a different logic from the original ext3 backup placement
> in groups multiples of 3, 5 and 7.
> --- a/fs/ext3/balloc.c
> +++ b/fs/ext3/balloc.c
> @@ -1510,9 +1529,15 @@ int ext3_bg_has_super(struct super_block
> */
> unsigned long ext3_bg_num_gdb(struct super_block *sb, int group)
> {
> - if (EXT3_HAS_RO_COMPAT_FEATURE(sb,EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)&&
> - !ext3_group_sparse(group))
> - return 0;
> - return EXT3_SB(sb)->s_gdb_count;
> + unsigned long first_meta_bg =
> + cpu_to_le32(EXT3_SB(sb)->s_es->s_first_meta_bg);
> + unsigned long metagroup = group / EXT3_DESC_PER_BLOCK(sb);
> +
> + if (!EXT3_HAS_INCOMPAT_FEATURE(sb,EXT3_FEATURE_INCOMPAT_META_BG)
> + || metagroup < first_meta_bg)
^^^^^^^^^^^^^^^^^^^^^^^^^
Comparison between little-endian and host-endian variables.
> + return ext3_bg_num_gdb_nometa(sb,group);
> +
> + return ext3_bg_num_gdb_meta(sb,group);
Em Sexta 20 Janeiro 2006 18:01, voc? escreveu:
> On Fri, Jan 20, 2006 at 06:37:21PM +0000, Glauber de Oliveira Costa wrote:
> > In filesystems with the meta block group flag on, ext3_bg_num_gdb()
> > fails to report the correct number of blocks used to store the group
> > descriptor backups in a given group. It happens because meta_bg
> > follows a different logic from the original ext3 backup placement
> > in groups multiples of 3, 5 and 7.
> >
> > --- a/fs/ext3/balloc.c
> > +++ b/fs/ext3/balloc.c
> > @@ -1510,9 +1529,15 @@ int ext3_bg_has_super(struct super_block
> > */
> > unsigned long ext3_bg_num_gdb(struct super_block *sb, int group)
> > {
> > - if
> > (EXT3_HAS_RO_COMPAT_FEATURE(sb,EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)&& -
> > !ext3_group_sparse(group))
> > - return 0;
> > - return EXT3_SB(sb)->s_gdb_count;
> > + unsigned long first_meta_bg =
> > + cpu_to_le32(EXT3_SB(sb)->s_es->s_first_meta_bg);
> > + unsigned long metagroup = group / EXT3_DESC_PER_BLOCK(sb);
> > +
> > + if (!EXT3_HAS_INCOMPAT_FEATURE(sb,EXT3_FEATURE_INCOMPAT_META_BG)
> > + || metagroup < first_meta_bg)
>
> ^^^^^^^^^^^^^^^^^^^^^^^^^
>
> Comparison between little-endian and host-endian variables.
I should have used le32_to_cpu() instead of cpu_to_le32() some lines above. It
was a minor typo error. I Will resend.
Thank you.
> > + return ext3_bg_num_gdb_nometa(sb,group);
> > +
> > + return ext3_bg_num_gdb_meta(sb,group);