[PATCH] ext4: Automatic setting of {INODE,BLOCK}_UNINIT flags

[PATCH] ext4: Automatic setting of {INODE,BLOCK}_UNINIT flags

[Tomas Racek]

When last inode from bg is freed, set the INODE_UNINIT flag, similarly
when last block is freed, set BLOCK_UNINIT flag. This can speed up
subsequent fsck run.

Signed-off-by: Tomas Racek <tracek@redhat.com>
---
 fs/ext4/ialloc.c  | 4 ++++
 fs/ext4/mballoc.c | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 4facdd2..6e4b982 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -289,6 +289,10 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
 
 	count = ext4_free_inodes_count(sb, gdp) + 1;
 	ext4_free_inodes_set(sb, gdp, count);
+
+	if (count == EXT4_INODES_PER_GROUP(sb))
+               gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_UNINIT);
+
 	if (is_directory) {
 		count = ext4_used_dirs_count(sb, gdp) - 1;
 		ext4_used_dirs_set(sb, gdp, count);
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 526e553..28bce35 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4665,6 +4665,10 @@ do_more:
 
 	ret = ext4_free_group_clusters(sb, gdp) + count_clusters;
 	ext4_free_group_clusters_set(sb, gdp, ret);
+
+	if(ret == EXT4_BLOCKS_PER_GROUP(sb))
+		gdp->bg_flags |= cpu_to_le16(EXT4_BG_BLOCK_UNINIT);
+
 	ext4_block_bitmap_csum_set(sb, block_group, gdp, bitmap_bh);
 	ext4_group_desc_csum_set(sb, block_group, gdp);
 	ext4_unlock_group(sb, block_group);
-- 
1.7.11.7

Re: [PATCH] ext4: Automatic setting of {INODE,BLOCK}_UNINIT flags

[Yongqiang Yang]

Does it make sense in no journal mode?

Thanks,
Yongqiang.

On Thu, Oct 25, 2012 at 3:25 PM, Tomas Racek <tracek@redhat.com> wrote:
> When last inode from bg is freed, set the INODE_UNINIT flag, similarly
> when last block is freed, set BLOCK_UNINIT flag. This can speed up
> subsequent fsck run.
>
> Signed-off-by: Tomas Racek <tracek@redhat.com>
> ---
>  fs/ext4/ialloc.c  | 4 ++++
>  fs/ext4/mballoc.c | 4 ++++
>  2 files changed, 8 insertions(+)
>
> diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
> index 4facdd2..6e4b982 100644
> --- a/fs/ext4/ialloc.c
> +++ b/fs/ext4/ialloc.c
> @@ -289,6 +289,10 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
>
>         count = ext4_free_inodes_count(sb, gdp) + 1;
>         ext4_free_inodes_set(sb, gdp, count);
> +
> +       if (count == EXT4_INODES_PER_GROUP(sb))
> +               gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_UNINIT);
> +
>         if (is_directory) {
>                 count = ext4_used_dirs_count(sb, gdp) - 1;
>                 ext4_used_dirs_set(sb, gdp, count);
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index 526e553..28bce35 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -4665,6 +4665,10 @@ do_more:
>
>         ret = ext4_free_group_clusters(sb, gdp) + count_clusters;
>         ext4_free_group_clusters_set(sb, gdp, ret);
> +
> +       if(ret == EXT4_BLOCKS_PER_GROUP(sb))
> +               gdp->bg_flags |= cpu_to_le16(EXT4_BG_BLOCK_UNINIT);
> +
>         ext4_block_bitmap_csum_set(sb, block_group, gdp, bitmap_bh);
>         ext4_group_desc_csum_set(sb, block_group, gdp);
>         ext4_unlock_group(sb, block_group);
> --
> 1.7.11.7
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html



-- 
Best Wishes
Yongqiang Yang

Re: [PATCH] ext4: Automatic setting of {INODE,BLOCK}_UNINIT flags

[Lukáš Czerner]

On Thu, 25 Oct 2012, Yongqiang Yang wrote:

> Date: Thu, 25 Oct 2012 15:44:48 +0800
> From: Yongqiang Yang <xiaoqiangnk@gmail.com>
> To: Tomas Racek <tracek@redhat.com>
> Cc: linux-ext4@vger.kernel.org, lczerner@redhat.com
> Subject: Re: [PATCH] ext4: Automatic setting of {INODE,BLOCK}_UNINIT flags
> 
> Does it make sense in no journal mode?

I am not sure why it would not ? It only makes changes to the block
group descriptors marking block/inode table as unitialized so we can
skip then in fsck.

Originally it has been only marked uninitialized when we create the
file system, but once we use the particular inode table or block
group bitmap it become initialized forever, even though it has been
completely freed since then. This patch fixes it so it can become
uninitialized again (granted that the flag name is not the best).

Advantages are that we can skip that in fsck, but also we might save
read from disk, because uninitialized descriptors are initialized in
memory rather hen read from the disk.

So my question is, why do you think this might not make sense in no
journal mode ? Maybe I am missing something.

Thanks!
-Lukas

> 
> Thanks,
> Yongqiang.
> 
> On Thu, Oct 25, 2012 at 3:25 PM, Tomas Racek <tracek@redhat.com> wrote:
> > When last inode from bg is freed, set the INODE_UNINIT flag, similarly
> > when last block is freed, set BLOCK_UNINIT flag. This can speed up
> > subsequent fsck run.
> >
> > Signed-off-by: Tomas Racek <tracek@redhat.com>
> > ---
> >  fs/ext4/ialloc.c  | 4 ++++
> >  fs/ext4/mballoc.c | 4 ++++
> >  2 files changed, 8 insertions(+)
> >
> > diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
> > index 4facdd2..6e4b982 100644
> > --- a/fs/ext4/ialloc.c
> > +++ b/fs/ext4/ialloc.c
> > @@ -289,6 +289,10 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
> >
> >         count = ext4_free_inodes_count(sb, gdp) + 1;
> >         ext4_free_inodes_set(sb, gdp, count);
> > +
> > +       if (count == EXT4_INODES_PER_GROUP(sb))
> > +               gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_UNINIT);
> > +
> >         if (is_directory) {
> >                 count = ext4_used_dirs_count(sb, gdp) - 1;
> >                 ext4_used_dirs_set(sb, gdp, count);
> > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> > index 526e553..28bce35 100644
> > --- a/fs/ext4/mballoc.c
> > +++ b/fs/ext4/mballoc.c
> > @@ -4665,6 +4665,10 @@ do_more:
> >
> >         ret = ext4_free_group_clusters(sb, gdp) + count_clusters;
> >         ext4_free_group_clusters_set(sb, gdp, ret);
> > +
> > +       if(ret == EXT4_BLOCKS_PER_GROUP(sb))
> > +               gdp->bg_flags |= cpu_to_le16(EXT4_BG_BLOCK_UNINIT);
> > +
> >         ext4_block_bitmap_csum_set(sb, block_group, gdp, bitmap_bh);
> >         ext4_group_desc_csum_set(sb, block_group, gdp);
> >         ext4_unlock_group(sb, block_group);
> > --
> > 1.7.11.7
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> 
> 
> 

Re: [PATCH] ext4: Automatic setting of {INODE,BLOCK}_UNINIT flags

[Yongqiang Yang]

>
> So my question is, why do you think this might not make sense in no
> journal mode ? Maybe I am missing something.
Yep, advantage is obvious, in no journal mode, if we delete a file
which is the last inode in a block group, and the uninit flag of inode
bitmap is flused to disk and directory referring the inode is not
flushed,  I don't know how fsck handles the situation currently.  If
fsck handles the situation, everything is ok. I meant maybe we should
check fsck too.

Yongqiang.
>
> Thanks!
> -Lukas
>
>>
>> Thanks,
>> Yongqiang.
>>
>> On Thu, Oct 25, 2012 at 3:25 PM, Tomas Racek <tracek@redhat.com> wrote:
>> > When last inode from bg is freed, set the INODE_UNINIT flag, similarly
>> > when last block is freed, set BLOCK_UNINIT flag. This can speed up
>> > subsequent fsck run.
>> >
>> > Signed-off-by: Tomas Racek <tracek@redhat.com>
>> > ---
>> >  fs/ext4/ialloc.c  | 4 ++++
>> >  fs/ext4/mballoc.c | 4 ++++
>> >  2 files changed, 8 insertions(+)
>> >
>> > diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
>> > index 4facdd2..6e4b982 100644
>> > --- a/fs/ext4/ialloc.c
>> > +++ b/fs/ext4/ialloc.c
>> > @@ -289,6 +289,10 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
>> >
>> >         count = ext4_free_inodes_count(sb, gdp) + 1;
>> >         ext4_free_inodes_set(sb, gdp, count);
>> > +
>> > +       if (count == EXT4_INODES_PER_GROUP(sb))
>> > +               gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_UNINIT);
>> > +
>> >         if (is_directory) {
>> >                 count = ext4_used_dirs_count(sb, gdp) - 1;
>> >                 ext4_used_dirs_set(sb, gdp, count);
>> > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
>> > index 526e553..28bce35 100644
>> > --- a/fs/ext4/mballoc.c
>> > +++ b/fs/ext4/mballoc.c
>> > @@ -4665,6 +4665,10 @@ do_more:
>> >
>> >         ret = ext4_free_group_clusters(sb, gdp) + count_clusters;
>> >         ext4_free_group_clusters_set(sb, gdp, ret);
>> > +
>> > +       if(ret == EXT4_BLOCKS_PER_GROUP(sb))
>> > +               gdp->bg_flags |= cpu_to_le16(EXT4_BG_BLOCK_UNINIT);
>> > +
>> >         ext4_block_bitmap_csum_set(sb, block_group, gdp, bitmap_bh);
>> >         ext4_group_desc_csum_set(sb, block_group, gdp);
>> >         ext4_unlock_group(sb, block_group);
>> > --
>> > 1.7.11.7
>> >
>> > --
>> > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
>> > the body of a message to majordomo@vger.kernel.org
>> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>>
>>
>>



-- 
Best Wishes
Yongqiang Yang

Re: [PATCH] ext4: Automatic setting of {INODE,BLOCK}_UNINIT flags

[Zheng Liu]

On Thu, Oct 25, 2012 at 07:39:06PM +0800, Yongqiang Yang wrote:
> >
> > So my question is, why do you think this might not make sense in no
> > journal mode ? Maybe I am missing something.
> Yep, advantage is obvious, in no journal mode, if we delete a file
> which is the last inode in a block group, and the uninit flag of inode
> bitmap is flused to disk and directory referring the inode is not
> flushed,  I don't know how fsck handles the situation currently.  If
> fsck handles the situation, everything is ok. I meant maybe we should
> check fsck too.

Hi Yongqiang,

It seems that it couldn't happen whether it is in no journal mode or
journal mode.  When a file is deleted, the dir entry will be updated
firstly, and then the block will be freed.  So the block is freed after
the dir entry is updated.  So when the last inode is freed, the dir
entry must be flushed to the disk.  Am I missing something?

Regards,
Zheng

Re: [PATCH] ext4: Automatic setting of {INODE,BLOCK}_UNINIT flags

[Lukáš Czerner]

[-- Attachment #1: Type: TEXT/PLAIN, Size: 1645 bytes --]

On Thu, 25 Oct 2012, Zheng Liu wrote:

> Date: Thu, 25 Oct 2012 20:54:09 +0800
> From: Zheng Liu <gnehzuil.liu@gmail.com>
> To: Yongqiang Yang <xiaoqiangnk@gmail.com>
> Cc: Lukáš Czerner <lczerner@redhat.com>, Tomas Racek <tracek@redhat.com>,
>     linux-ext4@vger.kernel.org
> Subject: Re: [PATCH] ext4: Automatic setting of {INODE,BLOCK}_UNINIT flags
> 
> On Thu, Oct 25, 2012 at 07:39:06PM +0800, Yongqiang Yang wrote:
> > >
> > > So my question is, why do you think this might not make sense in no
> > > journal mode ? Maybe I am missing something.
> > Yep, advantage is obvious, in no journal mode, if we delete a file
> > which is the last inode in a block group, and the uninit flag of inode
> > bitmap is flused to disk and directory referring the inode is not
> > flushed,  I don't know how fsck handles the situation currently.  If
> > fsck handles the situation, everything is ok. I meant maybe we should
> > check fsck too.
> 
> Hi Yongqiang,
> 
> It seems that it couldn't happen whether it is in no journal mode or
> journal mode.  When a file is deleted, the dir entry will be updated
> firstly, and then the block will be freed.  So the block is freed after
> the dir entry is updated.  So when the last inode is freed, the dir
> entry must be flushed to the disk.  Am I missing something?

I think you're right. Doing this the other way around would be a bug
regardless on this patch.

Thanks!
-Lukas

> 
> Regards,
> Zheng
> --
> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Re: [PATCH] ext4: Automatic setting of {INODE,BLOCK}_UNINIT flags

[Andreas Dilger]

On 2012-10-25, at 0:44, Yongqiang Yang <xiaoqiangnk@gmail.com> wrote:
> Does it make sense in no journal mode?

This is even more important in nojournal mode, since that will need to run e2fsck after every boot. 

Cheers, Andreas

> On Thu, Oct 25, 2012 at 3:25 PM, Tomas Racek <tracek@redhat.com> wrote:
>> When last inode from bg is freed, set the INODE_UNINIT flag, similarly
>> when last block is freed, set BLOCK_UNINIT flag. This can speed up
>> subsequent fsck run.
>> 
>> Signed-off-by: Tomas Racek <tracek@redhat.com>
>> ---
>> fs/ext4/ialloc.c  | 4 ++++
>> fs/ext4/mballoc.c | 4 ++++
>> 2 files changed, 8 insertions(+)
>> 
>> diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
>> index 4facdd2..6e4b982 100644
>> --- a/fs/ext4/ialloc.c
>> +++ b/fs/ext4/ialloc.c
>> @@ -289,6 +289,10 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
>> 
>>        count = ext4_free_inodes_count(sb, gdp) + 1;
>>        ext4_free_inodes_set(sb, gdp, count);
>> +
>> +       if (count == EXT4_INODES_PER_GROUP(sb))
>> +               gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_UNINIT);
>> +
>>        if (is_directory) {
>>                count = ext4_used_dirs_count(sb, gdp) - 1;
>>                ext4_used_dirs_set(sb, gdp, count);
>> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
>> index 526e553..28bce35 100644
>> --- a/fs/ext4/mballoc.c
>> +++ b/fs/ext4/mballoc.c
>> @@ -4665,6 +4665,10 @@ do_more:
>> 
>>        ret = ext4_free_group_clusters(sb, gdp) + count_clusters;
>>        ext4_free_group_clusters_set(sb, gdp, ret);
>> +
>> +       if(ret == EXT4_BLOCKS_PER_GROUP(sb))
>> +               gdp->bg_flags |= cpu_to_le16(EXT4_BG_BLOCK_UNINIT);
>> +
>>        ext4_block_bitmap_csum_set(sb, block_group, gdp, bitmap_bh);
>>        ext4_group_desc_csum_set(sb, block_group, gdp);
>>        ext4_unlock_group(sb, block_group);
>> --
>> 1.7.11.7
>> 
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> 
> 
> -- 
> Best Wishes
> Yongqiang Yang
> --
> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH] ext4: Automatic setting of {INODE,BLOCK}_UNINIT flags

[Theodore Ts'o]

On Thu, Oct 25, 2012 at 09:25:43AM +0200, Tomas Racek wrote:
> When last inode from bg is freed, set the INODE_UNINIT flag, similarly
> when last block is freed, set BLOCK_UNINIT flag. This can speed up
> subsequent fsck run.
> 
> Signed-off-by: Tomas Racek <tracek@redhat.com>

Could you make the following enhancements to your patch?

1)  Only do this if ext4_has_group_desc_csum(sb) is true

2)  Check to make sure the inode bitmap has only one bit set (the inode
    to be freed).  Basically, I don't want to set the BLOCK/INODE_UNINIT
    based just on the block group descriptor count, in case it got corrupted
     --- what, me paranoid?

    If there is other inodes set, then we need to call ext4_error()
    since we know the file system has gotten corrupted.

3)  If we can set BLOCK/INODE_UNINIT, we can skip modifying the bitmap
    block (since we won't consult the bitmap block if uninit is set).
    So that means we can skip calling get_write_access(), modifying
    the bitmap, updating the checksum, and then calling
    handle_dirty_metadata.  In fact, we can call ext4_forget(), so we
    can drop it from the buffer cache, and if it had been modified during
    the current transaction --- as part of an rm -rf, for example ---
    we don't need to include the bitmap block in the transaction.

(2) makes this patch much safer, and (3) should more than make up for
the overhead of scanning the the bitmap.

Thanks!!!

						- Ted

P.S.  Although the block bitmap is metadata, you can pass 0 for
is_metadata, since we don't need to revoke the block --- that's only
needed for extent tree blocks, indirect blocks, or directory blocks,
which could potentially get reused as a data block.  This isn't an
issue for the bitmap blocks, so we don't need to include a revoke
record in the journal.

Re: [PATCH] ext4: Automatic setting of {INODE,BLOCK}_UNINIT flags

[Tomas Racek]

----- Original Message -----
> On Thu, Oct 25, 2012 at 09:25:43AM +0200, Tomas Racek wrote:
> > When last inode from bg is freed, set the INODE_UNINIT flag,
> > similarly
> > when last block is freed, set BLOCK_UNINIT flag. This can speed up
> > subsequent fsck run.
> > 
> > Signed-off-by: Tomas Racek <tracek@redhat.com>
> 
> Could you make the following enhancements to your patch?
> 
> 1)  Only do this if ext4_has_group_desc_csum(sb) is true
> 
> 2)  Check to make sure the inode bitmap has only one bit set (the
> inode
>     to be freed).  Basically, I don't want to set the
>     BLOCK/INODE_UNINIT
>     based just on the block group descriptor count, in case it got
>     corrupted
>      --- what, me paranoid?
> 
>     If there is other inodes set, then we need to call ext4_error()
>     since we know the file system has gotten corrupted.
> 
> 3)  If we can set BLOCK/INODE_UNINIT, we can skip modifying the
> bitmap
>     block (since we won't consult the bitmap block if uninit is set).
>     So that means we can skip calling get_write_access(), modifying
>     the bitmap, updating the checksum, and then calling
>     handle_dirty_metadata.  In fact, we can call ext4_forget(), so we
>     can drop it from the buffer cache, and if it had been modified
>     during
>     the current transaction --- as part of an rm -rf, for example ---
>     we don't need to include the bitmap block in the transaction.
> 
> (2) makes this patch much safer, and (3) should more than make up for
> the overhead of scanning the the bitmap.
> 

Hi Ted,

sorry for late response, I've tried to add features you suggested to my patch (see below). Skipping modification of the bitmap however requires zeroing the bitmap when uninit flag is discarded, i.e. in new_inode. This adds some complexity and could slow things down. What's your opinion about it? I wrote the patches some time ago, one for inode_uninit follows as an example. If it's the right approach I'll rewrite them to be applicable to the current head and send them.

Thank you for your time and suggestions!

Tom


Subject: [PATCH v2 1/2] Set INODE_UNINIT flag when last inode is freed from BG

This can speed up subsequent fsck run.

Changes in v2: Suggestions by Ted Ts'o
	- only set this when ext4_has_group_desc_csum is true
	- check if there are no other set bits in the bitmap
	- skip modifying bitmap, checksum calculations and journal
	  operations

The last suggestion requires zeroing bitmap when UNINIT flag is
discarded (e.g. new inode allocation from bg with INODE_UNINIT)

Signed-off-by: Tomas Racek <tracek@redhat.com>
---
 fs/ext4/ialloc.c | 100 ++++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 73 insertions(+), 27 deletions(-)

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 3a100e7..04d50a8 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -221,6 +221,7 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
 	struct ext4_super_block *es;
 	struct ext4_sb_info *sbi;
 	int fatal = 0, err, count, cleared;
+	int uninit = 0;
 
 	if (!sb) {
 		printk(KERN_ERR "EXT4-fs: %s:%d: inode on "
@@ -266,36 +267,65 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
 	block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 	bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
 	bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
-	if (!bitmap_bh)
-		goto error_return;
 
-	BUFFER_TRACE(bitmap_bh, "get_write_access");
-	fatal = ext4_journal_get_write_access(handle, bitmap_bh);
-	if (fatal)
+	if (!bitmap_bh)
 		goto error_return;
 
-	fatal = -ESRCH;
 	gdp = ext4_get_group_desc(sb, block_group, &bh2);
 	if (gdp) {
 		BUFFER_TRACE(bh2, "get_write_access");
 		fatal = ext4_journal_get_write_access(handle, bh2);
 	}
+
+	if(fatal)
+		goto error_return;
+
 	ext4_lock_group(sb, block_group);
-	cleared = ext4_test_and_clear_bit(bit, bitmap_bh->b_data);
-	if (fatal || !cleared) {
+	count = ext4_free_inodes_count(sb, gdp) + 1;
+
+	if(ext4_has_group_desc_csum(sb) && count == EXT4_INODES_PER_GROUP(sb)) {
+		unsigned long first_bit = ext4_find_next_bit(bitmap_bh->b_data,\
+						 EXT4_INODES_PER_GROUP(sb), 0);
+		unsigned long next_bit = ext4_find_next_bit(bitmap_bh->b_data,\
+						EXT4_INODES_PER_GROUP(sb), bit + 1);
+		if(first_bit != bit || next_bit < EXT4_INODES_PER_GROUP(sb)) {
+			ext4_unlock_group(sb, block_group);
+			ext4_error(sb, "Inode bitmap corruption in block_group %u",\
+					block_group);
+			goto error_return;
+		}
+
+		gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_UNINIT);
+		uninit = 1;
+	}
+	else {
 		ext4_unlock_group(sb, block_group);
-		goto out;
+
+		BUFFER_TRACE(bitmap_bh, "get_write_access");
+		fatal = ext4_journal_get_write_access(handle, bitmap_bh);
+
+		if(fatal)
+			goto error_return;
+
+		ext4_lock_group(sb, block_group);
+		count = ext4_free_inodes_count(sb, gdp) + 1;
+
+		cleared = ext4_test_and_clear_bit(bit, bitmap_bh->b_data);
+		if(!cleared) {
+			ext4_unlock_group(sb, block_group);
+			goto out;
+		}
+		ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
+				   EXT4_INODES_PER_GROUP(sb) / 8);
 	}
 
-	count = ext4_free_inodes_count(sb, gdp) + 1;
 	ext4_free_inodes_set(sb, gdp, count);
+
 	if (is_directory) {
 		count = ext4_used_dirs_count(sb, gdp) - 1;
 		ext4_used_dirs_set(sb, gdp, count);
 		percpu_counter_dec(&sbi->s_dirs_counter);
 	}
-	ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
-				   EXT4_INODES_PER_GROUP(sb) / 8);
 	ext4_group_desc_csum_set(sb, block_group, gdp);
 	ext4_unlock_group(sb, block_group);
 
@@ -310,13 +340,20 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
 	BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
 	fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
 out:
-	if (cleared) {
-		BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
-		err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
-		if (!fatal)
-			fatal = err;
-	} else
-		ext4_error(sb, "bit already cleared for inode %lu", ino);
+	if(!uninit) {
+		if (cleared) {
+			BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
+			err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
+			if (!fatal)
+				fatal = err;
+		} else
+			ext4_error(sb, "bit already cleared for inode %lu", ino);
+	} else {
+		ext4_fsblk_t bitmap_blk = ext4_inode_bitmap(sb, gdp);
+		fatal = ext4_forget(handle, 0, inode, bitmap_bh, bitmap_blk);
+		ext4_std_error(sb, fatal);
+		return;
+	}
 
 error_return:
 	brelse(bitmap_bh);
@@ -650,6 +687,7 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, umode_t mode,
 	struct inode *ret;
 	ext4_group_t i;
 	ext4_group_t flex_group;
+	int free = -1;
 
 	/* Cannot create files in a deleted directory */
 	if (!dir || !dir->i_nlink)
@@ -730,7 +768,20 @@ repeat_in_this_group:
 		if (err)
 			goto fail;
 		ext4_lock_group(sb, group);
-		ret2 = ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data);
+		if(ext4_has_group_desc_csum(sb) &&
+		   gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
+
+			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
+			ext4_group_desc_csum_set(sb, group, gdp);
+			memset(inode_bitmap_bh->b_data, 0, sb->s_blocksize);
+			ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),\
+				sb->s_blocksize * 8, inode_bitmap_bh->b_data);
+			ext4_set_bit(ino, inode_bitmap_bh->b_data);
+			free = 0;
+			ret2 = 0;
+		}
+		else
+			ret2 = ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data);
 		ext4_unlock_group(sb, group);
 		ino++;		/* the inode bitmap is zero-based */
 		if (!ret2)
@@ -787,17 +838,12 @@ got:
 
 	/* Update the relevant bg descriptor fields */
 	if (ext4_has_group_desc_csum(sb)) {
-		int free;
 		struct ext4_group_info *grp = ext4_get_group_info(sb, group);
 
 		down_read(&grp->alloc_sem); /* protect vs itable lazyinit */
 		ext4_lock_group(sb, group); /* while we modify the bg desc */
-		free = EXT4_INODES_PER_GROUP(sb) -
-			ext4_itable_unused_count(sb, gdp);
-		if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
-			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
-			free = 0;
-		}
+		if(free != 0)
+			free = EXT4_INODES_PER_GROUP(sb) - ext4_itable_unused_count(sb, gdp);
 		/*
 		 * Check the relative inode number against the last used
 		 * relative inode number in this group. if it is greater
-- 
1.7.11.7