[PATCH] ext4: Fix a BUG in mb_mark

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* [PATCH] ext4: Fix a BUG in mb_mark_used during trim.
@ 2011-03-03  9:33 Tao Ma
  2011-03-03 10:01 ` Lukas Czerner
  0 siblings, 1 reply; 10+ messages in thread
From: Tao Ma @ 2011-03-03  9:33 UTC (permalink / raw)
  To: linux-ext4; +Cc: Theodore Ts'o

From: Tao Ma <boyu.mt@taobao.com>

In a bs=4096 volume, if we call FITRIM with the following parameter as
fstrim_range(start = 102400, len = 134144000, minlen = 10240),
we will trigger a BUG_ON.
BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));

Mar  4 00:55:52 boyu-tm kernel: ------------[ cut here ]------------
Mar  4 00:55:52 boyu-tm kernel: kernel BUG at fs/ext4/mballoc.c:1506!
Mar  4 01:21:09 boyu-tm kernel: Code: d4 00 00 00 00 49 89 fe 8b 56 0c 44 8b 7e 04 89 55 c4 48 8b 4f 28 89 d6 44 01 fe 48 63 d6 48 8b 41 18 48 c1 e0 03 48 39 c2 76 04 <0f> 0b eb fe 48 8b 55 b0 8b 47 34 3b 42 08 74 04 0f 0b eb fe 48
Mar  4 01:21:09 boyu-tm kernel: RIP  [<ffffffffa053eb42>] mb_mark_used+0x47/0x26c [ext4]
Mar  4 01:21:09 boyu-tm kernel:  RSP <ffff880121e45c38>
Mar  4 01:21:09 boyu-tm kernel: ---[ end trace 9f461696f6a9dcf2 ]---

The reason is that in ext4_trim_fs, the last_block is checked wrongly.
if (len >= EXT4_BLOCKS_PER_GROUP(sb))
	len -= (EXT4_BLOCKS_PER_GROUP(sb) - first_block);
else
	last_block = first_block + len;

So if len < EXT4_BLOCKS_PER_GROUP while first_block + len > EXT4_BLOCKS_PER_GROUP,
last_block will be set to a overflow value which exceeds EXT4_BLOCKS_PER_GROUP.

This patch fixes it and adjusts len accordingly.

Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
---
 fs/ext4/mballoc.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 29d7d17..ed63c3e 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4889,10 +4889,11 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
 			break;
 		}
 
-		if (len >= EXT4_BLOCKS_PER_GROUP(sb))
-			len -= (EXT4_BLOCKS_PER_GROUP(sb) - first_block);
+		if (first_block + len >= EXT4_BLOCKS_PER_GROUP(sb))
+			last_block = EXT4_BLOCKS_PER_GROUP(sb);
 		else
 			last_block = first_block + len;
+		len -= last_block - first_block;
 
 		if (e4b.bd_info->bb_free >= minlen) {
 			cnt = ext4_trim_all_free(sb, &e4b, first_block,
-- 
1.6.3.GIT


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* Re: [PATCH] ext4: Fix a BUG in mb_mark_used during trim.
  2011-03-03  9:33 [PATCH] ext4: Fix a BUG in mb_mark_used during trim Tao Ma
@ 2011-03-03 10:01 ` Lukas Czerner
  2011-03-03 10:13   ` Tao Ma
  0 siblings, 1 reply; 10+ messages in thread
From: Lukas Czerner @ 2011-03-03 10:01 UTC (permalink / raw)
  To: Tao Ma; +Cc: linux-ext4, Theodore Ts'o, lczerner

On Thu, 3 Mar 2011, Tao Ma wrote:

> From: Tao Ma <boyu.mt@taobao.com>
> 
> In a bs=4096 volume, if we call FITRIM with the following parameter as
> fstrim_range(start = 102400, len = 134144000, minlen = 10240),
> we will trigger a BUG_ON.
> BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));
> 
> Mar  4 00:55:52 boyu-tm kernel: ------------[ cut here ]------------
> Mar  4 00:55:52 boyu-tm kernel: kernel BUG at fs/ext4/mballoc.c:1506!
> Mar  4 01:21:09 boyu-tm kernel: Code: d4 00 00 00 00 49 89 fe 8b 56 0c 44 8b 7e 04 89 55 c4 48 8b 4f 28 89 d6 44 01 fe 48 63 d6 48 8b 41 18 48 c1 e0 03 48 39 c2 76 04 <0f> 0b eb fe 48 8b 55 b0 8b 47 34 3b 42 08 74 04 0f 0b eb fe 48
> Mar  4 01:21:09 boyu-tm kernel: RIP  [<ffffffffa053eb42>] mb_mark_used+0x47/0x26c [ext4]
> Mar  4 01:21:09 boyu-tm kernel:  RSP <ffff880121e45c38>
> Mar  4 01:21:09 boyu-tm kernel: ---[ end trace 9f461696f6a9dcf2 ]---
> 
> The reason is that in ext4_trim_fs, the last_block is checked wrongly.
> if (len >= EXT4_BLOCKS_PER_GROUP(sb))
> 	len -= (EXT4_BLOCKS_PER_GROUP(sb) - first_block);
> else
> 	last_block = first_block + len;
> 
> So if len < EXT4_BLOCKS_PER_GROUP while first_block + len > EXT4_BLOCKS_PER_GROUP,
> last_block will be set to a overflow value which exceeds EXT4_BLOCKS_PER_GROUP.
> 
> This patch fixes it and adjusts len accordingly.

Oh, thanks for spotting this. One comment though.

> 
> Cc: "Theodore Ts'o" <tytso@mit.edu>
> Signed-off-by: Tao Ma <boyu.mt@taobao.com>
> ---
>  fs/ext4/mballoc.c |    5 +++--
>  1 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index 29d7d17..ed63c3e 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -4889,10 +4889,11 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
>  			break;
>  		}
>  
> -		if (len >= EXT4_BLOCKS_PER_GROUP(sb))
> -			len -= (EXT4_BLOCKS_PER_GROUP(sb) - first_block);
> +		if (first_block + len >= EXT4_BLOCKS_PER_GROUP(sb))
> +			last_block = EXT4_BLOCKS_PER_GROUP(sb);
>  		else
>  			last_block = first_block + len;

Since last_block would not change until the last group, can we simplify
the condition ?

		if (first_block + len < EXT4_BLOCKS_PER_GROUP(sb))
			last_block = first_block + len;

> +		len -= last_block - first_block;
>  
>  		if (e4b.bd_info->bb_free >= minlen) {
>  			cnt = ext4_trim_all_free(sb, &e4b, first_block,
> 

Thanks!
-Lukas

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH] ext4: Fix a BUG in mb_mark_used during trim.
  2011-03-03 10:01 ` Lukas Czerner
@ 2011-03-03 10:13   ` Tao Ma
  2011-03-03 10:17     ` Lukas Czerner
  0 siblings, 1 reply; 10+ messages in thread
From: Tao Ma @ 2011-03-03 10:13 UTC (permalink / raw)
  To: Lukas Czerner; +Cc: linux-ext4, Theodore Ts'o

On 03/03/2011 06:01 PM, Lukas Czerner wrote:
> On Thu, 3 Mar 2011, Tao Ma wrote:
>
>    
>> From: Tao Ma<boyu.mt@taobao.com>
>>
>> In a bs=4096 volume, if we call FITRIM with the following parameter as
>> fstrim_range(start = 102400, len = 134144000, minlen = 10240),
>> we will trigger a BUG_ON.
>> BUG_ON(start + len>  (e4b->bd_sb->s_blocksize<<  3));
>>
>> Mar  4 00:55:52 boyu-tm kernel: ------------[ cut here ]------------
>> Mar  4 00:55:52 boyu-tm kernel: kernel BUG at fs/ext4/mballoc.c:1506!
>> Mar  4 01:21:09 boyu-tm kernel: Code: d4 00 00 00 00 49 89 fe 8b 56 0c 44 8b 7e 04 89 55 c4 48 8b 4f 28 89 d6 44 01 fe 48 63 d6 48 8b 41 18 48 c1 e0 03 48 39 c2 76 04<0f>  0b eb fe 48 8b 55 b0 8b 47 34 3b 42 08 74 04 0f 0b eb fe 48
>> Mar  4 01:21:09 boyu-tm kernel: RIP  [<ffffffffa053eb42>] mb_mark_used+0x47/0x26c [ext4]
>> Mar  4 01:21:09 boyu-tm kernel:  RSP<ffff880121e45c38>
>> Mar  4 01:21:09 boyu-tm kernel: ---[ end trace 9f461696f6a9dcf2 ]---
>>
>> The reason is that in ext4_trim_fs, the last_block is checked wrongly.
>> if (len>= EXT4_BLOCKS_PER_GROUP(sb))
>> 	len -= (EXT4_BLOCKS_PER_GROUP(sb) - first_block);
>> else
>> 	last_block = first_block + len;
>>
>> So if len<  EXT4_BLOCKS_PER_GROUP while first_block + len>  EXT4_BLOCKS_PER_GROUP,
>> last_block will be set to a overflow value which exceeds EXT4_BLOCKS_PER_GROUP.
>>
>> This patch fixes it and adjusts len accordingly.
>>      
> Oh, thanks for spotting this. One comment though.
>
>    
>> Cc: "Theodore Ts'o"<tytso@mit.edu>
>> Signed-off-by: Tao Ma<boyu.mt@taobao.com>
>> ---
>>   fs/ext4/mballoc.c |    5 +++--
>>   1 files changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
>> index 29d7d17..ed63c3e 100644
>> --- a/fs/ext4/mballoc.c
>> +++ b/fs/ext4/mballoc.c
>> @@ -4889,10 +4889,11 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
>>   			break;
>>   		}
>>
>> -		if (len>= EXT4_BLOCKS_PER_GROUP(sb))
>> -			len -= (EXT4_BLOCKS_PER_GROUP(sb) - first_block);
>> +		if (first_block + len>= EXT4_BLOCKS_PER_GROUP(sb))
>> +			last_block = EXT4_BLOCKS_PER_GROUP(sb);
>>   		else
>>   			last_block = first_block + len;
>>      
> Since last_block would not change until the last group, can we simplify
> the condition ?
>
> 		if (first_block + len<  EXT4_BLOCKS_PER_GROUP(sb))
> 			last_block = first_block + len;
>    
yes, it should work. But it is a bit tricky. And I guess we need a 
comment here
to describe the situation. Otherwise, the people who read the code would 
consider
why last_block won't be reset in case first _block + len >= 
EXT4_BLOCKS_PER_GROUP
every time. Agree?
>    
>> +		len -= last_block - first_block;
>>
>>   		if (e4b.bd_info->bb_free>= minlen) {
>>   			cnt = ext4_trim_all_free(sb,&e4b, first_block,
>>
>>      
> Thanks!
> -Lukas
>    
Regards,
Tao

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH] ext4: Fix a BUG in mb_mark_used during trim.
  2011-03-03 10:13   ` Tao Ma
@ 2011-03-03 10:17     ` Lukas Czerner
  2011-03-03 13:59       ` [PATCH v2] " Tao Ma
  0 siblings, 1 reply; 10+ messages in thread
From: Lukas Czerner @ 2011-03-03 10:17 UTC (permalink / raw)
  To: Tao Ma; +Cc: Lukas Czerner, linux-ext4, Theodore Ts'o

On Thu, 3 Mar 2011, Tao Ma wrote:

> On 03/03/2011 06:01 PM, Lukas Czerner wrote:
> > On Thu, 3 Mar 2011, Tao Ma wrote:
> > 
> >    
> > > From: Tao Ma<boyu.mt@taobao.com>
> > > 
> > > In a bs=4096 volume, if we call FITRIM with the following parameter as
> > > fstrim_range(start = 102400, len = 134144000, minlen = 10240),
> > > we will trigger a BUG_ON.
> > > BUG_ON(start + len>  (e4b->bd_sb->s_blocksize<<  3));
> > > 
> > > Mar  4 00:55:52 boyu-tm kernel: ------------[ cut here ]------------
> > > Mar  4 00:55:52 boyu-tm kernel: kernel BUG at fs/ext4/mballoc.c:1506!
> > > Mar  4 01:21:09 boyu-tm kernel: Code: d4 00 00 00 00 49 89 fe 8b 56 0c 44
> > > 8b 7e 04 89 55 c4 48 8b 4f 28 89 d6 44 01 fe 48 63 d6 48 8b 41 18 48 c1 e0
> > > 03 48 39 c2 76 04<0f>  0b eb fe 48 8b 55 b0 8b 47 34 3b 42 08 74 04 0f 0b
> > > eb fe 48
> > > Mar  4 01:21:09 boyu-tm kernel: RIP  [<ffffffffa053eb42>]
> > > mb_mark_used+0x47/0x26c [ext4]
> > > Mar  4 01:21:09 boyu-tm kernel:  RSP<ffff880121e45c38>
> > > Mar  4 01:21:09 boyu-tm kernel: ---[ end trace 9f461696f6a9dcf2 ]---
> > > 
> > > The reason is that in ext4_trim_fs, the last_block is checked wrongly.
> > > if (len>= EXT4_BLOCKS_PER_GROUP(sb))
> > > 	len -= (EXT4_BLOCKS_PER_GROUP(sb) - first_block);
> > > else
> > > 	last_block = first_block + len;
> > > 
> > > So if len<  EXT4_BLOCKS_PER_GROUP while first_block + len>
> > > EXT4_BLOCKS_PER_GROUP,
> > > last_block will be set to a overflow value which exceeds
> > > EXT4_BLOCKS_PER_GROUP.
> > > 
> > > This patch fixes it and adjusts len accordingly.
> > >      
> > Oh, thanks for spotting this. One comment though.
> > 
> >    
> > > Cc: "Theodore Ts'o"<tytso@mit.edu>
> > > Signed-off-by: Tao Ma<boyu.mt@taobao.com>
> > > ---
> > >   fs/ext4/mballoc.c |    5 +++--
> > >   1 files changed, 3 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> > > index 29d7d17..ed63c3e 100644
> > > --- a/fs/ext4/mballoc.c
> > > +++ b/fs/ext4/mballoc.c
> > > @@ -4889,10 +4889,11 @@ int ext4_trim_fs(struct super_block *sb, struct
> > > fstrim_range *range)
> > >   			break;
> > >   		}
> > > 
> > > -		if (len>= EXT4_BLOCKS_PER_GROUP(sb))
> > > -			len -= (EXT4_BLOCKS_PER_GROUP(sb) - first_block);
> > > +		if (first_block + len>= EXT4_BLOCKS_PER_GROUP(sb))
> > > +			last_block = EXT4_BLOCKS_PER_GROUP(sb);
> > >   		else
> > >   			last_block = first_block + len;
> > >      
> > Since last_block would not change until the last group, can we simplify
> > the condition ?
> > 
> > 		if (first_block + len<  EXT4_BLOCKS_PER_GROUP(sb))
> > 			last_block = first_block + len;
> >    
> yes, it should work. But it is a bit tricky. And I guess we need a comment
> here
> to describe the situation. Otherwise, the people who read the code would
> consider
> why last_block won't be reset in case first _block + len >=
> EXT4_BLOCKS_PER_GROUP
> every time. Agree?

Agree, comment would be useful.

Thanks!
-Lukas

> >    
> > > +		len -= last_block - first_block;
> > > 
> > >   		if (e4b.bd_info->bb_free>= minlen) {
> > >   			cnt = ext4_trim_all_free(sb,&e4b, first_block,
> > > 
> > >      
> > Thanks!
> > -Lukas
> >    
> Regards,
> Tao
> --
> 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
> 

-- 

^ permalink raw reply	[flat|nested] 10+ messages in thread

* [PATCH v2] ext4: Fix a BUG in mb_mark_used during trim.
  2011-03-03 10:17     ` Lukas Czerner
@ 2011-03-03 13:59       ` Tao Ma
  2011-03-03 14:20         ` Lukas Czerner
                           ` (3 more replies)
  0 siblings, 4 replies; 10+ messages in thread
From: Tao Ma @ 2011-03-03 13:59 UTC (permalink / raw)
  To: linux-ext4; +Cc: Lukas Czerner, Theodore Ts'o

From: Tao Ma <boyu.mt@taobao.com>

In a bs=4096 volume, if we call FITRIM with the following parameter as
fstrim_range(start = 102400, len = 134144000, minlen = 10240),
we will trigger a BUG_ON.
BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));

Mar  4 00:55:52 boyu-tm kernel: ------------[ cut here ]------------
Mar  4 00:55:52 boyu-tm kernel: kernel BUG at fs/ext4/mballoc.c:1506!
Mar  4 01:21:09 boyu-tm kernel: Code: d4 00 00 00 00 49 89 fe 8b 56 0c 44 8b 7e 04 89 55 c4 48 8b 4f 28 89 d6 44 01 fe 48 63 d6 48 8b 41 18 48 c1 e0 03 48 39 c2 76 04 <0f> 0b eb fe 48 8b 55 b0 8b 47 34 3b 42 08 74 04 0f 0b eb fe 48
Mar  4 01:21:09 boyu-tm kernel: RIP  [<ffffffffa053eb42>] mb_mark_used+0x47/0x26c [ext4]
Mar  4 01:21:09 boyu-tm kernel:  RSP <ffff880121e45c38>
Mar  4 01:21:09 boyu-tm kernel: ---[ end trace 9f461696f6a9dcf2 ]---

The reason is that in ext4_trim_fs, the last_block is checked wrongly.
if (len >= EXT4_BLOCKS_PER_GROUP(sb))
	len -= (EXT4_BLOCKS_PER_GROUP(sb) - first_block);
else
	last_block = first_block + len;

So if len < EXT4_BLOCKS_PER_GROUP while first_block + len > EXT4_BLOCKS_PER_GROUP,
last_block will be set to a overflow value which exceeds EXT4_BLOCKS_PER_GROUP.

This patch fixes it and adjusts len accordingly.

Cc: Lukas Czerner <lczerner@redhat.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
---
 fs/ext4/mballoc.c |   11 ++++++++---
 1 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 29d7d17..290b36c 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4889,10 +4889,15 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
 			break;
 		}
 
-		if (len >= EXT4_BLOCKS_PER_GROUP(sb))
-			len -= (EXT4_BLOCKS_PER_GROUP(sb) - first_block);
-		else
+		/*
+		 * For all the groups except the last one, last block will
+		 * always be EXT4_BLOCKS_PER_GROUP(sb), so we only need to
+		 * change it for the last group in which case start +
+		 * len < EXT4_BLOCKS_PER_GROUP(sb).
+		 */
+		if (first_block + len < EXT4_BLOCKS_PER_GROUP(sb))
 			last_block = first_block + len;
+		len -= last_block - first_block;
 
 		if (e4b.bd_info->bb_free >= minlen) {
 			cnt = ext4_trim_all_free(sb, &e4b, first_block,
-- 
1.6.3.GIT


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* Re: [PATCH v2] ext4: Fix a BUG in mb_mark_used during trim.
  2011-03-03 13:59       ` [PATCH v2] " Tao Ma
@ 2011-03-03 14:20         ` Lukas Czerner
       [not found]         ` <20110303141109.GB16191@infradead.org>
                           ` (2 subsequent siblings)
  3 siblings, 0 replies; 10+ messages in thread
From: Lukas Czerner @ 2011-03-03 14:20 UTC (permalink / raw)
  To: Tao Ma; +Cc: linux-ext4, Lukas Czerner, Theodore Ts'o

On Thu, 3 Mar 2011, Tao Ma wrote:

> From: Tao Ma <boyu.mt@taobao.com>
> 
> In a bs=4096 volume, if we call FITRIM with the following parameter as
> fstrim_range(start = 102400, len = 134144000, minlen = 10240),
> we will trigger a BUG_ON.
> BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));
> 
> Mar  4 00:55:52 boyu-tm kernel: ------------[ cut here ]------------
> Mar  4 00:55:52 boyu-tm kernel: kernel BUG at fs/ext4/mballoc.c:1506!
> Mar  4 01:21:09 boyu-tm kernel: Code: d4 00 00 00 00 49 89 fe 8b 56 0c 44 8b 7e 04 89 55 c4 48 8b 4f 28 89 d6 44 01 fe 48 63 d6 48 8b 41 18 48 c1 e0 03 48 39 c2 76 04 <0f> 0b eb fe 48 8b 55 b0 8b 47 34 3b 42 08 74 04 0f 0b eb fe 48
> Mar  4 01:21:09 boyu-tm kernel: RIP  [<ffffffffa053eb42>] mb_mark_used+0x47/0x26c [ext4]
> Mar  4 01:21:09 boyu-tm kernel:  RSP <ffff880121e45c38>
> Mar  4 01:21:09 boyu-tm kernel: ---[ end trace 9f461696f6a9dcf2 ]---
> 
> The reason is that in ext4_trim_fs, the last_block is checked wrongly.
> if (len >= EXT4_BLOCKS_PER_GROUP(sb))
> 	len -= (EXT4_BLOCKS_PER_GROUP(sb) - first_block);
> else
> 	last_block = first_block + len;
> 
> So if len < EXT4_BLOCKS_PER_GROUP while first_block + len > EXT4_BLOCKS_PER_GROUP,
> last_block will be set to a overflow value which exceeds EXT4_BLOCKS_PER_GROUP.
> 
> This patch fixes it and adjusts len accordingly.
> 
> Cc: Lukas Czerner <lczerner@redhat.com>
> Cc: "Theodore Ts'o" <tytso@mit.edu>
> Signed-off-by: Tao Ma <boyu.mt@taobao.com>
> ---
>  fs/ext4/mballoc.c |   11 ++++++++---
>  1 files changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index 29d7d17..290b36c 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -4889,10 +4889,15 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
>  			break;
>  		}
>  
> -		if (len >= EXT4_BLOCKS_PER_GROUP(sb))
> -			len -= (EXT4_BLOCKS_PER_GROUP(sb) - first_block);
> -		else
> +		/*
> +		 * For all the groups except the last one, last block will
> +		 * always be EXT4_BLOCKS_PER_GROUP(sb), so we only need to
> +		 * change it for the last group in which case start +
> +		 * len < EXT4_BLOCKS_PER_GROUP(sb).
> +		 */
> +		if (first_block + len < EXT4_BLOCKS_PER_GROUP(sb))
>  			last_block = first_block + len;
> +		len -= last_block - first_block;
>  
>  		if (e4b.bd_info->bb_free >= minlen) {
>  			cnt = ext4_trim_all_free(sb, &e4b, first_block,
> 

Looks good.

Thanks!
-Lukas

^ permalink raw reply	[flat|nested] 10+ messages in thread

[parent not found: <20110303141109.GB16191@infradead.org>]

* Re: [PATCH v2] ext4: Fix a BUG in mb_mark_used during trim.
       [not found]         ` <20110303141109.GB16191@infradead.org>
@ 2011-03-03 15:33           ` Tao Ma
  2011-03-03 15:38             ` Christoph Hellwig
  0 siblings, 1 reply; 10+ messages in thread
From: Tao Ma @ 2011-03-03 15:33 UTC (permalink / raw)
  To: Christoph Hellwig, linux-ext4

Hi Christoph,
On 03/03/2011 10:11 PM, Christoph Hellwig wrote:
> On Thu, Mar 03, 2011 at 09:59:34PM +0800, Tao Ma wrote:
>> From: Tao Ma<boyu.mt@taobao.com>
>>
>> In a bs=4096 volume, if we call FITRIM with the following parameter as
>> fstrim_range(start = 102400, len = 134144000, minlen = 10240),
> Can you add a xfstests regression test for this particular invocation?
> We already have Lukas' fstrim.c tester in the tree, so it could be a
> simple wrapper around it.
Actually these numbers are related to the block size of a ext4 volume.
To be more specific, with the above number, we have
first_block + block_len > EXT4_BLOCKS_PER_GROUP while
block_len < EXT4_BLOCKS_PER_GROUP.
So do you think it is generic enough for a test case in xfstests since 
now this
tool kit is also used to test xfs and btrfs?

Regards,
Tao





^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH v2] ext4: Fix a BUG in mb_mark_used during trim.
  2011-03-03 15:33           ` Tao Ma
@ 2011-03-03 15:38             ` Christoph Hellwig
  0 siblings, 0 replies; 10+ messages in thread
From: Christoph Hellwig @ 2011-03-03 15:38 UTC (permalink / raw)
  To: Tao Ma; +Cc: linux-ext4

On Thu, Mar 03, 2011 at 11:33:35PM +0800, Tao Ma wrote:
> Actually these numbers are related to the block size of a ext4 volume.
> To be more specific, with the above number, we have
> first_block + block_len > EXT4_BLOCKS_PER_GROUP while
> block_len < EXT4_BLOCKS_PER_GROUP.
> So do you think it is generic enough for a test case in xfstests
> since now this
> tool kit is also used to test xfs and btrfs?

xfstests also allows filesystem-specific tests.  Most of the specific
tests are for xfs, but there are few for udf right now as well.


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH v2] ext4: Fix a kernel panic in mb_mark_used during trim.
  2011-03-03 13:59       ` [PATCH v2] " Tao Ma
  2011-03-03 14:20         ` Lukas Czerner
       [not found]         ` <20110303141109.GB16191@infradead.org>
@ 2011-03-16 15:20         ` Tao Ma
  2011-03-23 19:47         ` [PATCH v2] ext4: Fix a BUG " Ted Ts'o
  3 siblings, 0 replies; 10+ messages in thread
From: Tao Ma @ 2011-03-16 15:20 UTC (permalink / raw)
  To: linux-ext4; +Cc: Lukas Czerner, Theodore Ts'o

Hi Ted,
	This is a fix for kernel panic in ext4. So any comment for it?

Regards,
Tao
On 03/03/2011 09:59 PM, Tao Ma wrote:
> From: Tao Ma <boyu.mt@taobao.com>
> 
> In a bs=4096 volume, if we call FITRIM with the following parameter as
> fstrim_range(start = 102400, len = 134144000, minlen = 10240),
> we will trigger a BUG_ON.
> BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));
> 
> Mar  4 00:55:52 boyu-tm kernel: ------------[ cut here ]------------
> Mar  4 00:55:52 boyu-tm kernel: kernel BUG at fs/ext4/mballoc.c:1506!
> Mar  4 01:21:09 boyu-tm kernel: Code: d4 00 00 00 00 49 89 fe 8b 56 0c 44 8b 7e 04 89 55 c4 48 8b 4f 28 89 d6 44 01 fe 48 63 d6 48 8b 41 18 48 c1 e0 03 48 39 c2 76 04 <0f> 0b eb fe 48 8b 55 b0 8b 47 34 3b 42 08 74 04 0f 0b eb fe 48
> Mar  4 01:21:09 boyu-tm kernel: RIP  [<ffffffffa053eb42>] mb_mark_used+0x47/0x26c [ext4]
> Mar  4 01:21:09 boyu-tm kernel:  RSP <ffff880121e45c38>
> Mar  4 01:21:09 boyu-tm kernel: ---[ end trace 9f461696f6a9dcf2 ]---
> 
> The reason is that in ext4_trim_fs, the last_block is checked wrongly.
> if (len >= EXT4_BLOCKS_PER_GROUP(sb))
> 	len -= (EXT4_BLOCKS_PER_GROUP(sb) - first_block);
> else
> 	last_block = first_block + len;
> 
> So if len < EXT4_BLOCKS_PER_GROUP while first_block + len > EXT4_BLOCKS_PER_GROUP,
> last_block will be set to a overflow value which exceeds EXT4_BLOCKS_PER_GROUP.
> 
> This patch fixes it and adjusts len accordingly.
> 
> Cc: Lukas Czerner <lczerner@redhat.com>
> Cc: "Theodore Ts'o" <tytso@mit.edu>
> Signed-off-by: Tao Ma <boyu.mt@taobao.com>
> ---
>  fs/ext4/mballoc.c |   11 ++++++++---
>  1 files changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index 29d7d17..290b36c 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -4889,10 +4889,15 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
>  			break;
>  		}
>  
> -		if (len >= EXT4_BLOCKS_PER_GROUP(sb))
> -			len -= (EXT4_BLOCKS_PER_GROUP(sb) - first_block);
> -		else
> +		/*
> +		 * For all the groups except the last one, last block will
> +		 * always be EXT4_BLOCKS_PER_GROUP(sb), so we only need to
> +		 * change it for the last group in which case start +
> +		 * len < EXT4_BLOCKS_PER_GROUP(sb).
> +		 */
> +		if (first_block + len < EXT4_BLOCKS_PER_GROUP(sb))
>  			last_block = first_block + len;
> +		len -= last_block - first_block;
>  
>  		if (e4b.bd_info->bb_free >= minlen) {
>  			cnt = ext4_trim_all_free(sb, &e4b, first_block,


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH v2] ext4: Fix a BUG in mb_mark_used during trim.
  2011-03-03 13:59       ` [PATCH v2] " Tao Ma
                           ` (2 preceding siblings ...)
  2011-03-16 15:20         ` [PATCH v2] ext4: Fix a kernel panic " Tao Ma
@ 2011-03-23 19:47         ` Ted Ts'o
  3 siblings, 0 replies; 10+ messages in thread
From: Ted Ts'o @ 2011-03-23 19:47 UTC (permalink / raw)
  To: Tao Ma; +Cc: linux-ext4, Lukas Czerner

Thanks, added to the ext4 patch queue.  My apologies for the delay.

	      	     	  	- Ted

On Thu, Mar 03, 2011 at 09:59:34PM +0800, Tao Ma wrote:
> From: Tao Ma <boyu.mt@taobao.com>
> 
> In a bs=4096 volume, if we call FITRIM with the following parameter as
> fstrim_range(start = 102400, len = 134144000, minlen = 10240),
> we will trigger a BUG_ON.
> BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));
> 

^ permalink raw reply	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2011-03-23 19:47 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2011-03-03  9:33 [PATCH] ext4: Fix a BUG in mb_mark_used during trim Tao Ma
2011-03-03 10:01 ` Lukas Czerner
2011-03-03 10:13   ` Tao Ma
2011-03-03 10:17     ` Lukas Czerner
2011-03-03 13:59       ` [PATCH v2] " Tao Ma
2011-03-03 14:20         ` Lukas Czerner
     [not found]         ` <20110303141109.GB16191@infradead.org>
2011-03-03 15:33           ` Tao Ma
2011-03-03 15:38             ` Christoph Hellwig
2011-03-16 15:20         ` [PATCH v2] ext4: Fix a kernel panic " Tao Ma
2011-03-23 19:47         ` [PATCH v2] ext4: Fix a BUG " Ted Ts'o

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