Patchwork [40/74] libext2fs: no need to clear BLOCK_UNINIT during ext2fs_reserve_super_and_bgd

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Submitter Darrick J. Wong
Date Dec. 11, 2013, 1:22 a.m.
Message ID <20131211012246.30655.88212.stgit@birch.djwong.org>
Download mbox | patch
Permalink /patch/299709/
State Accepted
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Comments

Darrick J. Wong - Dec. 11, 2013, 1:22 a.m.
Since the beginning of the uninit_bg feature, the kernel[1] and
e2fsck[2] have always been careful to detect the presence of the
BLOCK_UNINIT flag, and compute a block bitmap with any group metadata
blocks marked in that bitmap.  With that in mind, I think it's safe to
say that this is a design feature of uninit_bg.

Now that we've trained libext2fs to have this same behavior whenever
it's loading a block bitmap, we no longer need to unset BLOCK_UNINIT
for a group that contains only its own group metadata -- kernel,
e2fsck, and e2fsprogs will handle this correctly.

[1] kernel git 717d50e4971b81b96c0199c91cdf0039a8cb181a
    "Ext4: Uninitialized Block Groups"
[2] e2fsprogs git f5fa20078bfc05b554294fe9c5505375d7913e8c
    "Add support for EXT2_FEATURE_COMPAT_LAZY_BG"

Reported-by: Akira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 lib/ext2fs/alloc_sb.c |    2 --
 1 file changed, 2 deletions(-)



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Akira Fujita - Jan. 10, 2014, 8:17 a.m.
Hi,

>Now that we've trained libext2fs to have this same behavior whenever

>it's loading a block bitmap, we no longer need to unset BLOCK_UNINIT

>for a group that contains only its own group metadata -- kernel,

>e2fsck, and e2fsprogs will handle this correctly.


It seems to me that the problem (*) I reported is not fixed
after applying your 38-41 patches. Do we need extra patch for this?

(*)
http://marc.info/?l=linux-ext4&m=138242796915518&w=2

Regards,
Akira Fujita

>From: Darrick J. Wong [mailto:darrick.wong@oracle.com]

>Sent: Wednesday, December 11, 2013 10:23 AM

>To: tytso@mit.edu; darrick.wong@oracle.com

>Cc: Akira Fujita; linux-ext4@vger.kernel.org

>Subject: [PATCH 40/74] libext2fs: no need to clear BLOCK_UNINIT during ext2fs_reserve_super_and_bgd

>

>Since the beginning of the uninit_bg feature, the kernel[1] and

>e2fsck[2] have always been careful to detect the presence of the

>BLOCK_UNINIT flag, and compute a block bitmap with any group metadata

>blocks marked in that bitmap.  With that in mind, I think it's safe to

>say that this is a design feature of uninit_bg.

>

>Now that we've trained libext2fs to have this same behavior whenever

>it's loading a block bitmap, we no longer need to unset BLOCK_UNINIT

>for a group that contains only its own group metadata -- kernel,

>e2fsck, and e2fsprogs will handle this correctly.

>

>[1] kernel git 717d50e4971b81b96c0199c91cdf0039a8cb181a

>    "Ext4: Uninitialized Block Groups"

>[2] e2fsprogs git f5fa20078bfc05b554294fe9c5505375d7913e8c

>    "Add support for EXT2_FEATURE_COMPAT_LAZY_BG"

>

>Reported-by: Akira Fujita <a-fujita@rs.jp.nec.com>

>Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

>---

> lib/ext2fs/alloc_sb.c |    2 --

> 1 file changed, 2 deletions(-)

>

>

>diff --git a/lib/ext2fs/alloc_sb.c b/lib/ext2fs/alloc_sb.c

>index 223ec51..8788c00 100644

>--- a/lib/ext2fs/alloc_sb.c

>+++ b/lib/ext2fs/alloc_sb.c

>@@ -65,8 +65,6 @@ int ext2fs_reserve_super_and_bgd(ext2_filsys fs,

> 		ext2fs_mark_block_bitmap2(bmap, 0);

>

> 	if (old_desc_blk) {

>-		if (fs->super->s_reserved_gdt_blocks && fs->block_map == bmap)

>-			ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);

> 		num_blocks = old_desc_blocks;

> 		if (old_desc_blk + num_blocks >= ext2fs_blocks_count(fs->super))

> 			num_blocks = ext2fs_blocks_count(fs->super) -
Theodore Ts'o - Jan. 11, 2014, 7:18 p.m.
On Tue, Dec 10, 2013 at 05:22:46PM -0800, Darrick J. Wong wrote:
> Since the beginning of the uninit_bg feature, the kernel[1] and
> e2fsck[2] have always been careful to detect the presence of the
> BLOCK_UNINIT flag, and compute a block bitmap with any group metadata
> blocks marked in that bitmap.  With that in mind, I think it's safe to
> say that this is a design feature of uninit_bg.
> 
> Now that we've trained libext2fs to have this same behavior whenever
> it's loading a block bitmap, we no longer need to unset BLOCK_UNINIT
> for a group that contains only its own group metadata -- kernel,
> e2fsck, and e2fsprogs will handle this correctly.
> 
> [1] kernel git 717d50e4971b81b96c0199c91cdf0039a8cb181a
>     "Ext4: Uninitialized Block Groups"
> [2] e2fsprogs git f5fa20078bfc05b554294fe9c5505375d7913e8c
>     "Add support for EXT2_FEATURE_COMPAT_LAZY_BG"
> 
> Reported-by: Akira Fujita <a-fujita@rs.jp.nec.com>
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Thanks, applied.

						- Ted
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Patch

diff --git a/lib/ext2fs/alloc_sb.c b/lib/ext2fs/alloc_sb.c
index 223ec51..8788c00 100644
--- a/lib/ext2fs/alloc_sb.c
+++ b/lib/ext2fs/alloc_sb.c
@@ -65,8 +65,6 @@  int ext2fs_reserve_super_and_bgd(ext2_filsys fs,
 		ext2fs_mark_block_bitmap2(bmap, 0);
 
 	if (old_desc_blk) {
-		if (fs->super->s_reserved_gdt_blocks && fs->block_map == bmap)
-			ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
 		num_blocks = old_desc_blocks;
 		if (old_desc_blk + num_blocks >= ext2fs_blocks_count(fs->super))
 			num_blocks = ext2fs_blocks_count(fs->super) -