diff mbox

FIEMAP problem

Message ID 52025497.1090608@oracle.com
State New, archived
Headers show

Commit Message

jeff.liu Aug. 7, 2013, 2:07 p.m. UTC
On 08/07/2013 05:17 PM, David Weber wrote:

> Hi,
> 
> We are trying to use OCFS2 as VM storage. After running into problems with 
> qemu's disk_mirror feature we now think there could be a problem with the 
> FIEMAP ioctl in OCFS2.
> 
> As far as I understand the situation looks like this:
> Qemu inquiries the FS if the given section of the image is already allocated 
> via the FIEMAP ioctl [1]
> It especially checks if fm_mapped_extents is greater 0.
> OCFS2 reports on sections bigger 1048576 there would be 0 mapped_extents which 
> is wrong.
> 
> I extended a userspace FIEMAP util [2] a bit to specify the start and length 
> parameter [3] as an easier testcase.
> 
> When we create a big file which has no holes
> dd if=/dev/urandom of=/mnt/kvm-images/urandom.img bs=1M count=1000
> 
> We get on lower sections the expected output:
> ./a.out /mnt/kvm-images/urandom.img 10000 10
> start: 2710, length: a
> File /mnt/kvm-images/urandom.img has 1 extents:
> #       Logical          Physical         Length           Flags
> 0:      0000000000000000 0000004ca3f00000 000000000be00000 0000
> 
> But on sections >= 1048576 it reports there wouldn't be any extents which is 
> as far as I understand wrong:
> ./a.out /mnt/kvm-images/urandom.img 1048576 10
> start: 100000, length: a
> File /mnt/kvm-images/urandom.img has 0 extents:
> #       Logical          Physical         Length           Flags

Thanks for your report, looks this problem has existed over years.
As a quick response, could you please try the below fix?

From: Jie Liu <jeff.liu@oracle.com>

Call fiemap ioctl(2) with given start offset as well as an desired
mapping range should show extents if possible.  However, we calculate
the end offset of mapping via 'mapping_end -= cpos' before iterating
the extent records which would cause problems, e.g,

Cluster size 4096:
debugfs.ocfs2 1.6.3
        Block Size Bits: 12   Cluster Size Bits: 12

The extended fiemap test utility From David:
https://gist.github.com/anonymous/6172331

# dd if=/dev/urandom of=/ocfs2/test_file bs=1M count=1000
# ./fiemap /ocfs2/test_file 4096 10
start: 4096, length: 10
File /ocfs2/test_file has 0 extents:
#	Logical          Physical         Length           Flags
	^^^^^ <-- No extents

In this case, at ocfs2_fiemap(): cpos == mapping_end == 1. Hence the
loop of searching extent records was not executed at all.

This patch remove the in question 'mapping_end -= cpos', and loops
until the cpos is larger than the mapping_end instead.

# ./fiemap /ocfs2/test_file 4096 10
start: 4096, length: 10
File /ocfs2/test_file has 1 extents:
#	Logical          Physical         Length           Flags
0:	0000000000000000 0000000056a01000 0000000006a00000 0000

Reported-by: David Weber <wb@munzinger.de>
Cc: Mark Fashen <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Jie Liu <jeff.liu@oracle.com>
---
 fs/ocfs2/extent_map.c |    1 -
 1 file changed, 1 deletion(-)

Comments

David Weber Aug. 8, 2013, 9:16 a.m. UTC | #1
Am Mittwoch, 7. August 2013, 22:07:19 schrieb Jeff Liu:
> On 08/07/2013 05:17 PM, David Weber wrote:
> > Hi,
> > 
> > We are trying to use OCFS2 as VM storage. After running into problems with
> > qemu's disk_mirror feature we now think there could be a problem with the
> > FIEMAP ioctl in OCFS2.
> > 
> > As far as I understand the situation looks like this:
> > Qemu inquiries the FS if the given section of the image is already
> > allocated via the FIEMAP ioctl [1]
> > It especially checks if fm_mapped_extents is greater 0.
> > OCFS2 reports on sections bigger 1048576 there would be 0 mapped_extents
> > which is wrong.
> > 
> > I extended a userspace FIEMAP util [2] a bit to specify the start and
> > length parameter [3] as an easier testcase.
> > 
> > When we create a big file which has no holes
> > dd if=/dev/urandom of=/mnt/kvm-images/urandom.img bs=1M count=1000
> > 
> > We get on lower sections the expected output:
> > ./a.out /mnt/kvm-images/urandom.img 10000 10
> > start: 2710, length: a
> > File /mnt/kvm-images/urandom.img has 1 extents:
> > #       Logical          Physical         Length           Flags
> > 0:      0000000000000000 0000004ca3f00000 000000000be00000 0000
> > 
> > But on sections >= 1048576 it reports there wouldn't be any extents which
> > is as far as I understand wrong:
> > ./a.out /mnt/kvm-images/urandom.img 1048576 10
> > start: 100000, length: a
> > File /mnt/kvm-images/urandom.img has 0 extents:
> > #       Logical          Physical         Length           Flags
> 
> Thanks for your report, looks this problem has existed over years.
> As a quick response, could you please try the below fix?

Thank you very much! This solved the problems with qemu.

I found a fiemap-tester util[1] in the xfstests project and it runs fine on 
OCFS2 with 4K cluster size but fails with 1M. I have however no idea if this 
is a severe problem.

# gcc -DHAVE_FALLOCATE=1 -o fiemap-tester fiemap-tester.c 
# ./fiemap-tester /mnt/kvm-images/fiemap_test
Starting infinite run, if you don't see any output then its working properly.
HEY FS PERSON: your fs is weird.  I specifically wanted a
hole and you allocated a block anyway.  FIBMAP confirms that
you allocated a block, and the block is filled with 0's so
everything is kosher, but you still allocated a block when
didn't need to.  This may or may not be what you wanted,
which is why I'm only printing this message once, in case
you didn't do it on purpose. This was at block 0.
ERROR: preallocated extent is not marked with FIEMAP_EXTENT_UNWRITTEN: 0
map is 
'HDHPHHDDHPHPHPHDDHHPPDDPPPHHHPDDDPDHHHHDDDPPHPPPDPHHPPDPPHHDDPDPPHDHPDDDDPDPPDPHDDPPDDPPHDDPDHHHDDPDHPHPDPPDDHPHPPHDPHPHDDHDPDPDHDHPDDPHPPPHDPPDPDDHPHDDPPHPDHPPHPPHPHHPHDHPPDDPHDHHPPHPPDHPHPHDHPPDDDDPHHHPPPHHHDDDDPDPDDPPPHPHDPPPHDPDPHDDHPPPDPDHPHHPHDHHDHPDPHDDPPHDPPDDPDDPPDHPPDPDHHPHDHPPHDDHDPHPPPDHPDDDHDDHDPPHHDDPPDPDDHDHHPHDPHHPPPDPPDHDHHPPHDPHDPPHDPHHPPP'
logical: [       0..     255] phys: 132160512..132160767 flags: 0x000 tot: 256


[1] http://oss.sgi.com/cgi-bin/gitweb.cgi?p=xfs/cmds/xfstests.git;a=blob_plain;f=src/fiemap-tester.c;hb=HEAD


> 
> From: Jie Liu <jeff.liu@oracle.com>
> 
> Call fiemap ioctl(2) with given start offset as well as an desired
> mapping range should show extents if possible.  However, we calculate
> the end offset of mapping via 'mapping_end -= cpos' before iterating
> the extent records which would cause problems, e.g,
> 
> Cluster size 4096:
> debugfs.ocfs2 1.6.3
>         Block Size Bits: 12   Cluster Size Bits: 12
> 
> The extended fiemap test utility From David:
> https://gist.github.com/anonymous/6172331
> 
> # dd if=/dev/urandom of=/ocfs2/test_file bs=1M count=1000
> # ./fiemap /ocfs2/test_file 4096 10
> start: 4096, length: 10
> File /ocfs2/test_file has 0 extents:
> #	Logical          Physical         Length           Flags
> 	^^^^^ <-- No extents
> 
> In this case, at ocfs2_fiemap(): cpos == mapping_end == 1. Hence the
> loop of searching extent records was not executed at all.
> 
> This patch remove the in question 'mapping_end -= cpos', and loops
> until the cpos is larger than the mapping_end instead.
> 
> # ./fiemap /ocfs2/test_file 4096 10
> start: 4096, length: 10
> File /ocfs2/test_file has 1 extents:
> #	Logical          Physical         Length           Flags
> 0:	0000000000000000 0000000056a01000 0000000006a00000 0000
> 
> Reported-by: David Weber <wb@munzinger.de>
> Cc: Mark Fashen <mfasheh@suse.de>
> Cc: Joel Becker <jlbec@evilplan.org>
> Signed-off-by: Jie Liu <jeff.liu@oracle.com>
> ---
>  fs/ocfs2/extent_map.c |    1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c
> index 2487116..8460647 100644
> --- a/fs/ocfs2/extent_map.c
> +++ b/fs/ocfs2/extent_map.c
> @@ -781,7 +781,6 @@ int ocfs2_fiemap(struct inode *inode, struct
> fiemap_extent_info *fieinfo, cpos = map_start >> osb->s_clustersize_bits;
>  	mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
>  					       map_start + map_len);
> -	mapping_end -= cpos;
>  	is_last = 0;
>  	while (cpos < mapping_end && !is_last) {
>  		u32 fe_flags;
> 
> > We're running linux-3.11-rc4 plus the following patches:
> > [PATCH V2] ocfs2: update inode size after zeroed the hole
> > [PATCH RESEND] ocfs2: fix NULL pointer dereference in
> > ocfs2_duplicate_clusters_by_page
> > NULL pointer dereference at	ocfs2_dir_foreach_blk_id
> > [patch v3] ocfs2: ocfs2: fix recent memory corruption bug
> > 
> > o2info --volinfo  /dev/drbd0
> > 
> >        Label: kvm-images
> >        
> >         UUID: BE7C101466AD4F2196A849C7A6031263
> >   
> >   Block Size: 4096
> > 
> > Cluster Size: 1048576
> > 
> >   Node Slots: 8
> >   
> >     Features: backup-super strict-journal-super sparse extended-slotmap
> >     Features: inline-data xattr indexed-dirs refcount discontig-bg
> >     unwritten
> > 
> > Thanks in advance!
> > 
> > Cheers,
> > David
> > 
> > 
> > [1]
> > http://git.qemu.org/?p=qemu.git;a=blob;f=block/raw-posix.c;h=ba721d3f5bd9
> > 8a6b62791c2e20dbf2894021ad76;hb=HEAD#l1087
> > 
> > [2]
> > http://smackerelofopinion.blogspot.de/2010/01/using-fiemap-ioctl-to-get-f
> > ile-extents.html
> > 
> > [3] https://gist.github.com/anonymous/6172331
> > 
> > 
> > _______________________________________________
> > Ocfs2-devel mailing list
> > Ocfs2-devel@oss.oracle.com
> > https://oss.oracle.com/mailman/listinfo/ocfs2-devel
Sunil Mushran Aug. 8, 2013, 2:30 p.m. UTC | #2
Interesting. Please can you print the inode disk using the command below. The file path is minus the mounted dir.

debugfs.ocfs2 -R "stat /relative/path/to/file" /dev/DEVICE

It is saying that the fs has allocated a block when it did not need to. It could be that the test utility does not handle blocks larger than 4K, or the fiemap ioctl has a bug or the fs is indeed allocating a block when it does not need to. The above command will show us the actual layout on disk.

On Aug 8, 2013, at 2:16 AM, David Weber <wb@munzinger.de> wrote:

> Am Mittwoch, 7. August 2013, 22:07:19 schrieb Jeff Liu:
>> On 08/07/2013 05:17 PM, David Weber wrote:
>>> Hi,
>>> 
>>> We are trying to use OCFS2 as VM storage. After running into problems with
>>> qemu's disk_mirror feature we now think there could be a problem with the
>>> FIEMAP ioctl in OCFS2.
>>> 
>>> As far as I understand the situation looks like this:
>>> Qemu inquiries the FS if the given section of the image is already
>>> allocated via the FIEMAP ioctl [1]
>>> It especially checks if fm_mapped_extents is greater 0.
>>> OCFS2 reports on sections bigger 1048576 there would be 0 mapped_extents
>>> which is wrong.
>>> 
>>> I extended a userspace FIEMAP util [2] a bit to specify the start and
>>> length parameter [3] as an easier testcase.
>>> 
>>> When we create a big file which has no holes
>>> dd if=/dev/urandom of=/mnt/kvm-images/urandom.img bs=1M count=1000
>>> 
>>> We get on lower sections the expected output:
>>> ./a.out /mnt/kvm-images/urandom.img 10000 10
>>> start: 2710, length: a
>>> File /mnt/kvm-images/urandom.img has 1 extents:
>>> #       Logical          Physical         Length           Flags
>>> 0:      0000000000000000 0000004ca3f00000 000000000be00000 0000
>>> 
>>> But on sections >= 1048576 it reports there wouldn't be any extents which
>>> is as far as I understand wrong:
>>> ./a.out /mnt/kvm-images/urandom.img 1048576 10
>>> start: 100000, length: a
>>> File /mnt/kvm-images/urandom.img has 0 extents:
>>> #       Logical          Physical         Length           Flags
>> 
>> Thanks for your report, looks this problem has existed over years.
>> As a quick response, could you please try the below fix?
> 
> Thank you very much! This solved the problems with qemu.
> 
> I found a fiemap-tester util[1] in the xfstests project and it runs fine on 
> OCFS2 with 4K cluster size but fails with 1M. I have however no idea if this 
> is a severe problem.
> 
> # gcc -DHAVE_FALLOCATE=1 -o fiemap-tester fiemap-tester.c 
> # ./fiemap-tester /mnt/kvm-images/fiemap_test
> Starting infinite run, if you don't see any output then its working properly.
> HEY FS PERSON: your fs is weird.  I specifically wanted a
> hole and you allocated a block anyway.  FIBMAP confirms that
> you allocated a block, and the block is filled with 0's so
> everything is kosher, but you still allocated a block when
> didn't need to.  This may or may not be what you wanted,
> which is why I'm only printing this message once, in case
> you didn't do it on purpose. This was at block 0.
> ERROR: preallocated extent is not marked with FIEMAP_EXTENT_UNWRITTEN: 0
> map is 
> 'HDHPHHDDHPHPHPHDDHHPPDDPPPHHHPDDDPDHHHHDDDPPHPPPDPHHPPDPPHHDDPDPPHDHPDDDDPDPPDPHDDPPDDPPHDDPDHHHDDPDHPHPDPPDDHPHPPHDPHPHDDHDPDPDHDHPDDPHPPPHDPPDPDDHPHDDPPHPDHPPHPPHPHHPHDHPPDDPHDHHPPHPPDHPHPHDHPPDDDDPHHHPPPHHHDDDDPDPDDPPPHPHDPPPHDPDPHDDHPPPDPDHPHHPHDHHDHPDPHDDPPHDPPDDPDDPPDHPPDPDHHPHDHPPHDDHDPHPPPDHPDDDHDDHDPPHHDDPPDPDDHDHHPHDPHHPPPDPPDHDHHPPHDPHDPPHDPHHPPP'
> logical: [       0..     255] phys: 132160512..132160767 flags: 0x000 tot: 256
> 
> 
> [1] http://oss.sgi.com/cgi-bin/gitweb.cgi?p=xfs/cmds/xfstests.git;a=blob_plain;f=src/fiemap-tester.c;hb=HEAD
> 
> 
>> 
>> From: Jie Liu <jeff.liu@oracle.com>
>> 
>> Call fiemap ioctl(2) with given start offset as well as an desired
>> mapping range should show extents if possible.  However, we calculate
>> the end offset of mapping via 'mapping_end -= cpos' before iterating
>> the extent records which would cause problems, e.g,
>> 
>> Cluster size 4096:
>> debugfs.ocfs2 1.6.3
>>        Block Size Bits: 12   Cluster Size Bits: 12
>> 
>> The extended fiemap test utility From David:
>> https://gist.github.com/anonymous/6172331
>> 
>> # dd if=/dev/urandom of=/ocfs2/test_file bs=1M count=1000
>> # ./fiemap /ocfs2/test_file 4096 10
>> start: 4096, length: 10
>> File /ocfs2/test_file has 0 extents:
>> #    Logical          Physical         Length           Flags
>>    ^^^^^ <-- No extents
>> 
>> In this case, at ocfs2_fiemap(): cpos == mapping_end == 1. Hence the
>> loop of searching extent records was not executed at all.
>> 
>> This patch remove the in question 'mapping_end -= cpos', and loops
>> until the cpos is larger than the mapping_end instead.
>> 
>> # ./fiemap /ocfs2/test_file 4096 10
>> start: 4096, length: 10
>> File /ocfs2/test_file has 1 extents:
>> #    Logical          Physical         Length           Flags
>> 0:    0000000000000000 0000000056a01000 0000000006a00000 0000
>> 
>> Reported-by: David Weber <wb@munzinger.de>
>> Cc: Mark Fashen <mfasheh@suse.de>
>> Cc: Joel Becker <jlbec@evilplan.org>
>> Signed-off-by: Jie Liu <jeff.liu@oracle.com>
>> ---
>> fs/ocfs2/extent_map.c |    1 -
>> 1 file changed, 1 deletion(-)
>> 
>> diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c
>> index 2487116..8460647 100644
>> --- a/fs/ocfs2/extent_map.c
>> +++ b/fs/ocfs2/extent_map.c
>> @@ -781,7 +781,6 @@ int ocfs2_fiemap(struct inode *inode, struct
>> fiemap_extent_info *fieinfo, cpos = map_start >> osb->s_clustersize_bits;
>>    mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
>>                           map_start + map_len);
>> -    mapping_end -= cpos;
>>    is_last = 0;
>>    while (cpos < mapping_end && !is_last) {
>>        u32 fe_flags;
>> 
>>> We're running linux-3.11-rc4 plus the following patches:
>>> [PATCH V2] ocfs2: update inode size after zeroed the hole
>>> [PATCH RESEND] ocfs2: fix NULL pointer dereference in
>>> ocfs2_duplicate_clusters_by_page
>>> NULL pointer dereference at    ocfs2_dir_foreach_blk_id
>>> [patch v3] ocfs2: ocfs2: fix recent memory corruption bug
>>> 
>>> o2info --volinfo  /dev/drbd0
>>> 
>>>       Label: kvm-images
>>> 
>>>        UUID: BE7C101466AD4F2196A849C7A6031263
>>> 
>>>  Block Size: 4096
>>> 
>>> Cluster Size: 1048576
>>> 
>>>  Node Slots: 8
>>> 
>>>    Features: backup-super strict-journal-super sparse extended-slotmap
>>>    Features: inline-data xattr indexed-dirs refcount discontig-bg
>>>    unwritten
>>> 
>>> Thanks in advance!
>>> 
>>> Cheers,
>>> David
>>> 
>>> 
>>> [1]
>>> http://git.qemu.org/?p=qemu.git;a=blob;f=block/raw-posix.c;h=ba721d3f5bd9
>>> 8a6b62791c2e20dbf2894021ad76;hb=HEAD#l1087
>>> 
>>> [2]
>>> http://smackerelofopinion.blogspot.de/2010/01/using-fiemap-ioctl-to-get-f
>>> ile-extents.html
>>> 
>>> [3] https://gist.github.com/anonymous/6172331
>>> 
>>> 
>>> _______________________________________________
>>> Ocfs2-devel mailing list
>>> Ocfs2-devel@oss.oracle.com
>>> https://oss.oracle.com/mailman/listinfo/ocfs2-devel
> 
> _______________________________________________
> Ocfs2-devel mailing list
> Ocfs2-devel@oss.oracle.com
> https://oss.oracle.com/mailman/listinfo/ocfs2-devel
David Weber Aug. 8, 2013, 3:09 p.m. UTC | #3
Am Donnerstag, 8. August 2013, 07:30:27 schrieb Sunil Mushran:
> Interesting. Please can you print the inode disk using the command below.
> The file path is minus the mounted dir.
> 
> debugfs.ocfs2 -R "stat /relative/path/to/file" /dev/DEVICE
> 
> It is saying that the fs has allocated a block when it did not need to. It
> could be that the test utility does not handle blocks larger than 4K, or
> the fiemap ioctl has a bug or the fs is indeed allocating a block when it
> does not need to. The above command will show us the actual layout on disk.

Thank you for looking into this!

# ./fiemap-tester /mnt/kvm-images/fiemap_new
Starting infinite run, if you don't see any output then its working properly.
HEY FS PERSON: your fs is weird.  I specifically wanted a
hole and you allocated a block anyway.  FIBMAP confirms that
you allocated a block, and the block is filled with 0's so
everything is kosher, but you still allocated a block when
didn't need to.  This may or may not be what you wanted,
which is why I'm only printing this message once, in case
you didn't do it on purpose. This was at block 0.
ERROR: preallocated extent is not marked with FIEMAP_EXTENT_UNWRITTEN: 0
map is 
'HDHPHHDDHPHPHPHDDHHPPDDPPPHHHPDDDPDHHHHDDDPPHPPPDPHHPPDPPHHDDPDPPHDHPDDDDPDPPDPHDDPPDDPPHDDPDHHHDDPDHPHPDPPDDHPHPPHDPHPHDDHDPDPDHDHPDDPHPPPHDPPDPDDHPHDDPPHPDHPPHPPHPHHPHDHPPDDPHDHHPPHPPDHPHPHDHPPDDDDPHHHPPPHHHDDDDPDPDDPPPHPHDPPPHDPDPHDDHPPPDPDHPHHPHDHHDHPDPHDDPPHDPPDDPDDPPDHPPDPDHHPHDHPPHDDHDPHPPPDHPDDDHDDHDPPHHDDPPDPDDHDHHPHDPHHPPPDPPDHDHHPPHDPHDPPHDPHHPPP'
logical: [       0..     255] phys: 206615552..206615807 flags: 0x000 tot: 256
Problem comparing fiemap and map

# debugfs.ocfs2 -R "stat /fiemap_new" /dev/drbd0
        Inode: 92668161   Mode: 0644   Generation: 3713753505 (0xdd5b61a1)
        FS Generation: 2357962590 (0x8c8ba75e)
        CRC32: 00000000   ECC: 0000
        Type: Regular   Attr: 0x0   Flags: Valid 
        Dynamic Features: (0x0) 
        User: 0 (root)   Group: 0 (root)   Size: 1470464
        Links: 1   Clusters: 2
        ctime: 0x5203b200 0x991cd -- Thu Aug  8 16:58:08.627149 2013
        atime: 0x5203b200 0xc0accc -- Thu Aug  8 16:58:08.12627148 2013
        mtime: 0x5203b200 0x991cd -- Thu Aug  8 16:58:08.627149 2013
        dtime: 0x0 -- Thu Jan  1 01:00:00 1970
        Refcount Block: 0
        Last Extblk: 0   Orphan Slot: 0
        Sub Alloc Slot: 0   Sub Alloc Bit: 1
        Tree Depth: 0   Count: 243   Next Free Rec: 2
        ## Offset        Clusters       Block#          Flags
        0  0             1              206615552       0x0 
        1  1             1              206619648       0x0 


> On Aug 8, 2013, at 2:16 AM, David Weber <wb@munzinger.de> wrote:
> > Am Mittwoch, 7. August 2013, 22:07:19 schrieb Jeff Liu:
> >> On 08/07/2013 05:17 PM, David Weber wrote:
> >>> Hi,
> >>> 
> >>> We are trying to use OCFS2 as VM storage. After running into problems
> >>> with
> >>> qemu's disk_mirror feature we now think there could be a problem with
> >>> the
> >>> FIEMAP ioctl in OCFS2.
> >>> 
> >>> As far as I understand the situation looks like this:
> >>> Qemu inquiries the FS if the given section of the image is already
> >>> allocated via the FIEMAP ioctl [1]
> >>> It especially checks if fm_mapped_extents is greater 0.
> >>> OCFS2 reports on sections bigger 1048576 there would be 0 mapped_extents
> >>> which is wrong.
> >>> 
> >>> I extended a userspace FIEMAP util [2] a bit to specify the start and
> >>> length parameter [3] as an easier testcase.
> >>> 
> >>> When we create a big file which has no holes
> >>> dd if=/dev/urandom of=/mnt/kvm-images/urandom.img bs=1M count=1000
> >>> 
> >>> We get on lower sections the expected output:
> >>> ./a.out /mnt/kvm-images/urandom.img 10000 10
> >>> start: 2710, length: a
> >>> File /mnt/kvm-images/urandom.img has 1 extents:
> >>> #       Logical          Physical         Length           Flags
> >>> 0:      0000000000000000 0000004ca3f00000 000000000be00000 0000
> >>> 
> >>> But on sections >= 1048576 it reports there wouldn't be any extents
> >>> which
> >>> is as far as I understand wrong:
> >>> ./a.out /mnt/kvm-images/urandom.img 1048576 10
> >>> start: 100000, length: a
> >>> File /mnt/kvm-images/urandom.img has 0 extents:
> >>> #       Logical          Physical         Length           Flags
> >> 
> >> Thanks for your report, looks this problem has existed over years.
> >> As a quick response, could you please try the below fix?
> > 
> > Thank you very much! This solved the problems with qemu.
> > 
> > I found a fiemap-tester util[1] in the xfstests project and it runs fine
> > on
> > OCFS2 with 4K cluster size but fails with 1M. I have however no idea if
> > this is a severe problem.
> > 
> > # gcc -DHAVE_FALLOCATE=1 -o fiemap-tester fiemap-tester.c
> > # ./fiemap-tester /mnt/kvm-images/fiemap_test
> > Starting infinite run, if you don't see any output then its working
> > properly. HEY FS PERSON: your fs is weird.  I specifically wanted a
> > hole and you allocated a block anyway.  FIBMAP confirms that
> > you allocated a block, and the block is filled with 0's so
> > everything is kosher, but you still allocated a block when
> > didn't need to.  This may or may not be what you wanted,
> > which is why I'm only printing this message once, in case
> > you didn't do it on purpose. This was at block 0.
> > ERROR: preallocated extent is not marked with FIEMAP_EXTENT_UNWRITTEN: 0
> > map is
> > 'HDHPHHDDHPHPHPHDDHHPPDDPPPHHHPDDDPDHHHHDDDPPHPPPDPHHPPDPPHHDDPDPPHDHPDDDD
> > PDPPDPHDDPPDDPPHDDPDHHHDDPDHPHPDPPDDHPHPPHDPHPHDDHDPDPDHDHPDDPHPPPHDPPDPDD
> > HPHDDPPHPDHPPHPPHPHHPHDHPPDDPHDHHPPHPPDHPHPHDHPPDDDDPHHHPPPHHHDDDDPDPDDPPP
> > HPHDPPPHDPDPHDDHPPPDPDHPHHPHDHHDHPDPHDDPPHDPPDDPDDPPDHPPDPDHHPHDHPPHDDHDPH
> > PPPDHPDDDHDDHDPPHHDDPPDPDDHDHHPHDPHHPPPDPPDHDHHPPHDPHDPPHDPHHPPP' logical:
> > [       0..     255] phys: 132160512..132160767 flags: 0x000 tot: 256
> > 
> > 
> > [1]
> > http://oss.sgi.com/cgi-bin/gitweb.cgi?p=xfs/cmds/xfstests.git;a=blob_plai
> > n;f=src/fiemap-tester.c;hb=HEAD> 
> >> From: Jie Liu <jeff.liu@oracle.com>
> >> 
> >> Call fiemap ioctl(2) with given start offset as well as an desired
> >> mapping range should show extents if possible.  However, we calculate
> >> the end offset of mapping via 'mapping_end -= cpos' before iterating
> >> the extent records which would cause problems, e.g,
> >> 
> >> Cluster size 4096:
> >> debugfs.ocfs2 1.6.3
> >> 
> >>        Block Size Bits: 12   Cluster Size Bits: 12
> >> 
> >> The extended fiemap test utility From David:
> >> https://gist.github.com/anonymous/6172331
> >> 
> >> # dd if=/dev/urandom of=/ocfs2/test_file bs=1M count=1000
> >> # ./fiemap /ocfs2/test_file 4096 10
> >> start: 4096, length: 10
> >> File /ocfs2/test_file has 0 extents:
> >> #    Logical          Physical         Length           Flags
> >> 
> >>    ^^^^^ <-- No extents
> >> 
> >> In this case, at ocfs2_fiemap(): cpos == mapping_end == 1. Hence the
> >> loop of searching extent records was not executed at all.
> >> 
> >> This patch remove the in question 'mapping_end -= cpos', and loops
> >> until the cpos is larger than the mapping_end instead.
> >> 
> >> # ./fiemap /ocfs2/test_file 4096 10
> >> start: 4096, length: 10
> >> File /ocfs2/test_file has 1 extents:
> >> #    Logical          Physical         Length           Flags
> >> 0:    0000000000000000 0000000056a01000 0000000006a00000 0000
> >> 
> >> Reported-by: David Weber <wb@munzinger.de>
> >> Cc: Mark Fashen <mfasheh@suse.de>
> >> Cc: Joel Becker <jlbec@evilplan.org>
> >> Signed-off-by: Jie Liu <jeff.liu@oracle.com>
> >> ---
> >> fs/ocfs2/extent_map.c |    1 -
> >> 1 file changed, 1 deletion(-)
> >> 
> >> diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c
> >> index 2487116..8460647 100644
> >> --- a/fs/ocfs2/extent_map.c
> >> +++ b/fs/ocfs2/extent_map.c
> >> @@ -781,7 +781,6 @@ int ocfs2_fiemap(struct inode *inode, struct
> >> fiemap_extent_info *fieinfo, cpos = map_start >> osb->s_clustersize_bits;
> >> 
> >>    mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
> >>    
> >>                           map_start + map_len);
> >> 
> >> -    mapping_end -= cpos;
> >> 
> >>    is_last = 0;
> >>    while (cpos < mapping_end && !is_last) {
> >>    
> >>        u32 fe_flags;
> >>> 
> >>> We're running linux-3.11-rc4 plus the following patches:
> >>> [PATCH V2] ocfs2: update inode size after zeroed the hole
> >>> [PATCH RESEND] ocfs2: fix NULL pointer dereference in
> >>> ocfs2_duplicate_clusters_by_page
> >>> NULL pointer dereference at    ocfs2_dir_foreach_blk_id
> >>> [patch v3] ocfs2: ocfs2: fix recent memory corruption bug
> >>> 
> >>> o2info --volinfo  /dev/drbd0
> >>> 
> >>>       Label: kvm-images
> >>>       
> >>>        UUID: BE7C101466AD4F2196A849C7A6031263
> >>>  
> >>>  Block Size: 4096
> >>> 
> >>> Cluster Size: 1048576
> >>> 
> >>>  Node Slots: 8
> >>>  
> >>>    Features: backup-super strict-journal-super sparse extended-slotmap
> >>>    Features: inline-data xattr indexed-dirs refcount discontig-bg
> >>>    unwritten
> >>> 
> >>> Thanks in advance!
> >>> 
> >>> Cheers,
> >>> David
> >>> 
> >>> 
> >>> [1]
> >>> http://git.qemu.org/?p=qemu.git;a=blob;f=block/raw-posix.c;h=ba721d3f5bd
> >>> 9
> >>> 8a6b62791c2e20dbf2894021ad76;hb=HEAD#l1087
> >>> 
> >>> [2]
> >>> http://smackerelofopinion.blogspot.de/2010/01/using-fiemap-ioctl-to-get-> >>> f
> >>> ile-extents.html
> >>> 
> >>> [3] https://gist.github.com/anonymous/6172331
> >>> 
> >>> 
> >>> _______________________________________________
> >>> Ocfs2-devel mailing list
> >>> Ocfs2-devel@oss.oracle.com
> >>> https://oss.oracle.com/mailman/listinfo/ocfs2-devel
> > 
> > _______________________________________________
> > Ocfs2-devel mailing list
> > Ocfs2-devel@oss.oracle.com
> > https://oss.oracle.com/mailman/listinfo/ocfs2-devel
Sunil Mushran Aug. 8, 2013, 4:20 p.m. UTC | #4
So it's a test issue. The utility assumes the fs allocates in 4K units.
That's why it only works when clustersize is 4K.


On Thu, Aug 8, 2013 at 8:09 AM, David Weber <wb@munzinger.de> wrote:

> Am Donnerstag, 8. August 2013, 07:30:27 schrieb Sunil Mushran:
> > Interesting. Please can you print the inode disk using the command below.
> > The file path is minus the mounted dir.
> >
> > debugfs.ocfs2 -R "stat /relative/path/to/file" /dev/DEVICE
> >
> > It is saying that the fs has allocated a block when it did not need to.
> It
> > could be that the test utility does not handle blocks larger than 4K, or
> > the fiemap ioctl has a bug or the fs is indeed allocating a block when it
> > does not need to. The above command will show us the actual layout on
> disk.
>
> Thank you for looking into this!
>
> # ./fiemap-tester /mnt/kvm-images/fiemap_new
> Starting infinite run, if you don't see any output then its working
> properly.
> HEY FS PERSON: your fs is weird.  I specifically wanted a
> hole and you allocated a block anyway.  FIBMAP confirms that
> you allocated a block, and the block is filled with 0's so
> everything is kosher, but you still allocated a block when
> didn't need to.  This may or may not be what you wanted,
> which is why I'm only printing this message once, in case
> you didn't do it on purpose. This was at block 0.
> ERROR: preallocated extent is not marked with FIEMAP_EXTENT_UNWRITTEN: 0
> map is
>
> 'HDHPHHDDHPHPHPHDDHHPPDDPPPHHHPDDDPDHHHHDDDPPHPPPDPHHPPDPPHHDDPDPPHDHPDDDDPDPPDPHDDPPDDPPHDDPDHHHDDPDHPHPDPPDDHPHPPHDPHPHDDHDPDPDHDHPDDPHPPPHDPPDPDDHPHDDPPHPDHPPHPPHPHHPHDHPPDDPHDHHPPHPPDHPHPHDHPPDDDDPHHHPPPHHHDDDDPDPDDPPPHPHDPPPHDPDPHDDHPPPDPDHPHHPHDHHDHPDPHDDPPHDPPDDPDDPPDHPPDPDHHPHDHPPHDDHDPHPPPDHPDDDHDDHDPPHHDDPPDPDDHDHHPHDPHHPPPDPPDHDHHPPHDPHDPPHDPHHPPP'
> logical: [       0..     255] phys: 206615552..206615807 flags: 0x000 tot:
> 256
> Problem comparing fiemap and map
>
> # debugfs.ocfs2 -R "stat /fiemap_new" /dev/drbd0
>         Inode: 92668161   Mode: 0644   Generation: 3713753505 (0xdd5b61a1)
>         FS Generation: 2357962590 (0x8c8ba75e)
>         CRC32: 00000000   ECC: 0000
>         Type: Regular   Attr: 0x0   Flags: Valid
>         Dynamic Features: (0x0)
>         User: 0 (root)   Group: 0 (root)   Size: 1470464
>         Links: 1   Clusters: 2
>         ctime: 0x5203b200 0x991cd -- Thu Aug  8 16:58:08.627149 2013
>         atime: 0x5203b200 0xc0accc -- Thu Aug  8 16:58:08.12627148 2013
>         mtime: 0x5203b200 0x991cd -- Thu Aug  8 16:58:08.627149 2013
>         dtime: 0x0 -- Thu Jan  1 01:00:00 1970
>         Refcount Block: 0
>         Last Extblk: 0   Orphan Slot: 0
>         Sub Alloc Slot: 0   Sub Alloc Bit: 1
>         Tree Depth: 0   Count: 243   Next Free Rec: 2
>         ## Offset        Clusters       Block#          Flags
>         0  0             1              206615552       0x0
>         1  1             1              206619648       0x0
>
>
> > On Aug 8, 2013, at 2:16 AM, David Weber <wb@munzinger.de> wrote:
> > > Am Mittwoch, 7. August 2013, 22:07:19 schrieb Jeff Liu:
> > >> On 08/07/2013 05:17 PM, David Weber wrote:
> > >>> Hi,
> > >>>
> > >>> We are trying to use OCFS2 as VM storage. After running into problems
> > >>> with
> > >>> qemu's disk_mirror feature we now think there could be a problem with
> > >>> the
> > >>> FIEMAP ioctl in OCFS2.
> > >>>
> > >>> As far as I understand the situation looks like this:
> > >>> Qemu inquiries the FS if the given section of the image is already
> > >>> allocated via the FIEMAP ioctl [1]
> > >>> It especially checks if fm_mapped_extents is greater 0.
> > >>> OCFS2 reports on sections bigger 1048576 there would be 0
> mapped_extents
> > >>> which is wrong.
> > >>>
> > >>> I extended a userspace FIEMAP util [2] a bit to specify the start and
> > >>> length parameter [3] as an easier testcase.
> > >>>
> > >>> When we create a big file which has no holes
> > >>> dd if=/dev/urandom of=/mnt/kvm-images/urandom.img bs=1M count=1000
> > >>>
> > >>> We get on lower sections the expected output:
> > >>> ./a.out /mnt/kvm-images/urandom.img 10000 10
> > >>> start: 2710, length: a
> > >>> File /mnt/kvm-images/urandom.img has 1 extents:
> > >>> #       Logical          Physical         Length           Flags
> > >>> 0:      0000000000000000 0000004ca3f00000 000000000be00000 0000
> > >>>
> > >>> But on sections >= 1048576 it reports there wouldn't be any extents
> > >>> which
> > >>> is as far as I understand wrong:
> > >>> ./a.out /mnt/kvm-images/urandom.img 1048576 10
> > >>> start: 100000, length: a
> > >>> File /mnt/kvm-images/urandom.img has 0 extents:
> > >>> #       Logical          Physical         Length           Flags
> > >>
> > >> Thanks for your report, looks this problem has existed over years.
> > >> As a quick response, could you please try the below fix?
> > >
> > > Thank you very much! This solved the problems with qemu.
> > >
> > > I found a fiemap-tester util[1] in the xfstests project and it runs
> fine
> > > on
> > > OCFS2 with 4K cluster size but fails with 1M. I have however no idea if
> > > this is a severe problem.
> > >
> > > # gcc -DHAVE_FALLOCATE=1 -o fiemap-tester fiemap-tester.c
> > > # ./fiemap-tester /mnt/kvm-images/fiemap_test
> > > Starting infinite run, if you don't see any output then its working
> > > properly. HEY FS PERSON: your fs is weird.  I specifically wanted a
> > > hole and you allocated a block anyway.  FIBMAP confirms that
> > > you allocated a block, and the block is filled with 0's so
> > > everything is kosher, but you still allocated a block when
> > > didn't need to.  This may or may not be what you wanted,
> > > which is why I'm only printing this message once, in case
> > > you didn't do it on purpose. This was at block 0.
> > > ERROR: preallocated extent is not marked with FIEMAP_EXTENT_UNWRITTEN:
> 0
> > > map is
> > >
> 'HDHPHHDDHPHPHPHDDHHPPDDPPPHHHPDDDPDHHHHDDDPPHPPPDPHHPPDPPHHDDPDPPHDHPDDDD
> > >
> PDPPDPHDDPPDDPPHDDPDHHHDDPDHPHPDPPDDHPHPPHDPHPHDDHDPDPDHDHPDDPHPPPHDPPDPDD
> > >
> HPHDDPPHPDHPPHPPHPHHPHDHPPDDPHDHHPPHPPDHPHPHDHPPDDDDPHHHPPPHHHDDDDPDPDDPPP
> > >
> HPHDPPPHDPDPHDDHPPPDPDHPHHPHDHHDHPDPHDDPPHDPPDDPDDPPDHPPDPDHHPHDHPPHDDHDPH
> > > PPPDHPDDDHDDHDPPHHDDPPDPDDHDHHPHDPHHPPPDPPDHDHHPPHDPHDPPHDPHHPPP'
> logical:
> > > [       0..     255] phys: 132160512..132160767 flags: 0x000 tot: 256
> > >
> > >
> > > [1]
> > >
> http://oss.sgi.com/cgi-bin/gitweb.cgi?p=xfs/cmds/xfstests.git;a=blob_plai
> > > n;f=src/fiemap-tester.c;hb=HEAD>
> > >> From: Jie Liu <jeff.liu@oracle.com>
> > >>
> > >> Call fiemap ioctl(2) with given start offset as well as an desired
> > >> mapping range should show extents if possible.  However, we calculate
> > >> the end offset of mapping via 'mapping_end -= cpos' before iterating
> > >> the extent records which would cause problems, e.g,
> > >>
> > >> Cluster size 4096:
> > >> debugfs.ocfs2 1.6.3
> > >>
> > >>        Block Size Bits: 12   Cluster Size Bits: 12
> > >>
> > >> The extended fiemap test utility From David:
> > >> https://gist.github.com/anonymous/6172331
> > >>
> > >> # dd if=/dev/urandom of=/ocfs2/test_file bs=1M count=1000
> > >> # ./fiemap /ocfs2/test_file 4096 10
> > >> start: 4096, length: 10
> > >> File /ocfs2/test_file has 0 extents:
> > >> #    Logical          Physical         Length           Flags
> > >>
> > >>    ^^^^^ <-- No extents
> > >>
> > >> In this case, at ocfs2_fiemap(): cpos == mapping_end == 1. Hence the
> > >> loop of searching extent records was not executed at all.
> > >>
> > >> This patch remove the in question 'mapping_end -= cpos', and loops
> > >> until the cpos is larger than the mapping_end instead.
> > >>
> > >> # ./fiemap /ocfs2/test_file 4096 10
> > >> start: 4096, length: 10
> > >> File /ocfs2/test_file has 1 extents:
> > >> #    Logical          Physical         Length           Flags
> > >> 0:    0000000000000000 0000000056a01000 0000000006a00000 0000
> > >>
> > >> Reported-by: David Weber <wb@munzinger.de>
> > >> Cc: Mark Fashen <mfasheh@suse.de>
> > >> Cc: Joel Becker <jlbec@evilplan.org>
> > >> Signed-off-by: Jie Liu <jeff.liu@oracle.com>
> > >> ---
> > >> fs/ocfs2/extent_map.c |    1 -
> > >> 1 file changed, 1 deletion(-)
> > >>
> > >> diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c
> > >> index 2487116..8460647 100644
> > >> --- a/fs/ocfs2/extent_map.c
> > >> +++ b/fs/ocfs2/extent_map.c
> > >> @@ -781,7 +781,6 @@ int ocfs2_fiemap(struct inode *inode, struct
> > >> fiemap_extent_info *fieinfo, cpos = map_start >>
> osb->s_clustersize_bits;
> > >>
> > >>    mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
> > >>
> > >>                           map_start + map_len);
> > >>
> > >> -    mapping_end -= cpos;
> > >>
> > >>    is_last = 0;
> > >>    while (cpos < mapping_end && !is_last) {
> > >>
> > >>        u32 fe_flags;
> > >>>
> > >>> We're running linux-3.11-rc4 plus the following patches:
> > >>> [PATCH V2] ocfs2: update inode size after zeroed the hole
> > >>> [PATCH RESEND] ocfs2: fix NULL pointer dereference in
> > >>> ocfs2_duplicate_clusters_by_page
> > >>> NULL pointer dereference at    ocfs2_dir_foreach_blk_id
> > >>> [patch v3] ocfs2: ocfs2: fix recent memory corruption bug
> > >>>
> > >>> o2info --volinfo  /dev/drbd0
> > >>>
> > >>>       Label: kvm-images
> > >>>
> > >>>        UUID: BE7C101466AD4F2196A849C7A6031263
> > >>>
> > >>>  Block Size: 4096
> > >>>
> > >>> Cluster Size: 1048576
> > >>>
> > >>>  Node Slots: 8
> > >>>
> > >>>    Features: backup-super strict-journal-super sparse
> extended-slotmap
> > >>>    Features: inline-data xattr indexed-dirs refcount discontig-bg
> > >>>    unwritten
> > >>>
> > >>> Thanks in advance!
> > >>>
> > >>> Cheers,
> > >>> David
> > >>>
> > >>>
> > >>> [1]
> > >>>
> http://git.qemu.org/?p=qemu.git;a=blob;f=block/raw-posix.c;h=ba721d3f5bd
> > >>> 9
> > >>> 8a6b62791c2e20dbf2894021ad76;hb=HEAD#l1087
> > >>>
> > >>> [2]
> > >>>
> http://smackerelofopinion.blogspot.de/2010/01/using-fiemap-ioctl-to-get->
> >>> f
> > >>> ile-extents.html
> > >>>
> > >>> [3] https://gist.github.com/anonymous/6172331
> > >>>
> > >>>
> > >>> _______________________________________________
> > >>> Ocfs2-devel mailing list
> > >>> Ocfs2-devel@oss.oracle.com
> > >>> https://oss.oracle.com/mailman/listinfo/ocfs2-devel
> > >
> > > _______________________________________________
> > > Ocfs2-devel mailing list
> > > Ocfs2-devel@oss.oracle.com
> > > https://oss.oracle.com/mailman/listinfo/ocfs2-devel
>
David Weber Aug. 27, 2013, 8:18 a.m. UTC | #5
Am Donnerstag, 8. August 2013, 09:20:45 schrieb Sunil Mushran:
> So it's a test issue. The utility assumes the fs allocates in 4K units.
> That's why it only works when clustersize is 4K.

Thanks for the clarification!

The patch seems to have solved our problem. It would be great if it could be 
pushed to Linux.

Cheers,
David

> 
> On Thu, Aug 8, 2013 at 8:09 AM, David Weber <wb@munzinger.de> wrote:
> > Am Donnerstag, 8. August 2013, 07:30:27 schrieb Sunil Mushran:
> > > Interesting. Please can you print the inode disk using the command
> > > below.
> > > The file path is minus the mounted dir.
> > > 
> > > debugfs.ocfs2 -R "stat /relative/path/to/file" /dev/DEVICE
> > > 
> > > It is saying that the fs has allocated a block when it did not need to.
> > 
> > It
> > 
> > > could be that the test utility does not handle blocks larger than 4K, or
> > > the fiemap ioctl has a bug or the fs is indeed allocating a block when
> > > it
> > > does not need to. The above command will show us the actual layout on
> > 
> > disk.
> > 
> > Thank you for looking into this!
> > 
> > # ./fiemap-tester /mnt/kvm-images/fiemap_new
> > Starting infinite run, if you don't see any output then its working
> > properly.
> > HEY FS PERSON: your fs is weird.  I specifically wanted a
> > hole and you allocated a block anyway.  FIBMAP confirms that
> > you allocated a block, and the block is filled with 0's so
> > everything is kosher, but you still allocated a block when
> > didn't need to.  This may or may not be what you wanted,
> > which is why I'm only printing this message once, in case
> > you didn't do it on purpose. This was at block 0.
> > ERROR: preallocated extent is not marked with FIEMAP_EXTENT_UNWRITTEN: 0
> > map is
> > 
> > 'HDHPHHDDHPHPHPHDDHHPPDDPPPHHHPDDDPDHHHHDDDPPHPPPDPHHPPDPPHHDDPDPPHDHPDDDD
> > PDPPDPHDDPPDDPPHDDPDHHHDDPDHPHPDPPDDHPHPPHDPHPHDDHDPDPDHDHPDDPHPPPHDPPDPDD
> > HPHDDPPHPDHPPHPPHPHHPHDHPPDDPHDHHPPHPPDHPHPHDHPPDDDDPHHHPPPHHHDDDDPDPDDPPP
> > HPHDPPPHDPDPHDDHPPPDPDHPHHPHDHHDHPDPHDDPPHDPPDDPDDPPDHPPDPDHHPHDHPPHDDHDPH
> > PPPDHPDDDHDDHDPPHHDDPPDPDDHDHHPHDPHHPPPDPPDHDHHPPHDPHDPPHDPHHPPP' logical:
> > [       0..     255] phys: 206615552..206615807 flags: 0x000 tot: 256
> > Problem comparing fiemap and map
> > 
> > # debugfs.ocfs2 -R "stat /fiemap_new" /dev/drbd0
> > 
> >         Inode: 92668161   Mode: 0644   Generation: 3713753505 (0xdd5b61a1)
> >         FS Generation: 2357962590 (0x8c8ba75e)
> >         CRC32: 00000000   ECC: 0000
> >         Type: Regular   Attr: 0x0   Flags: Valid
> >         Dynamic Features: (0x0)
> >         User: 0 (root)   Group: 0 (root)   Size: 1470464
> >         Links: 1   Clusters: 2
> >         ctime: 0x5203b200 0x991cd -- Thu Aug  8 16:58:08.627149 2013
> >         atime: 0x5203b200 0xc0accc -- Thu Aug  8 16:58:08.12627148 2013
> >         mtime: 0x5203b200 0x991cd -- Thu Aug  8 16:58:08.627149 2013
> >         dtime: 0x0 -- Thu Jan  1 01:00:00 1970
> >         Refcount Block: 0
> >         Last Extblk: 0   Orphan Slot: 0
> >         Sub Alloc Slot: 0   Sub Alloc Bit: 1
> >         Tree Depth: 0   Count: 243   Next Free Rec: 2
> >         ## Offset        Clusters       Block#          Flags
> >         0  0             1              206615552       0x0
> >         1  1             1              206619648       0x0
> > > 
> > > On Aug 8, 2013, at 2:16 AM, David Weber <wb@munzinger.de> wrote:
> > > > Am Mittwoch, 7. August 2013, 22:07:19 schrieb Jeff Liu:
> > > >> On 08/07/2013 05:17 PM, David Weber wrote:
> > > >>> Hi,
> > > >>> 
> > > >>> We are trying to use OCFS2 as VM storage. After running into
> > > >>> problems
> > > >>> with
> > > >>> qemu's disk_mirror feature we now think there could be a problem
> > > >>> with
> > > >>> the
> > > >>> FIEMAP ioctl in OCFS2.
> > > >>> 
> > > >>> As far as I understand the situation looks like this:
> > > >>> Qemu inquiries the FS if the given section of the image is already
> > > >>> allocated via the FIEMAP ioctl [1]
> > > >>> It especially checks if fm_mapped_extents is greater 0.
> > > >>> OCFS2 reports on sections bigger 1048576 there would be 0
> > 
> > mapped_extents
> > 
> > > >>> which is wrong.
> > > >>> 
> > > >>> I extended a userspace FIEMAP util [2] a bit to specify the start
> > > >>> and
> > > >>> length parameter [3] as an easier testcase.
> > > >>> 
> > > >>> When we create a big file which has no holes
> > > >>> dd if=/dev/urandom of=/mnt/kvm-images/urandom.img bs=1M count=1000
> > > >>> 
> > > >>> We get on lower sections the expected output:
> > > >>> ./a.out /mnt/kvm-images/urandom.img 10000 10
> > > >>> start: 2710, length: a
> > > >>> File /mnt/kvm-images/urandom.img has 1 extents:
> > > >>> #       Logical          Physical         Length           Flags
> > > >>> 0:      0000000000000000 0000004ca3f00000 000000000be00000 0000
> > > >>> 
> > > >>> But on sections >= 1048576 it reports there wouldn't be any extents
> > > >>> which
> > > >>> is as far as I understand wrong:
> > > >>> ./a.out /mnt/kvm-images/urandom.img 1048576 10
> > > >>> start: 100000, length: a
> > > >>> File /mnt/kvm-images/urandom.img has 0 extents:
> > > >>> #       Logical          Physical         Length           Flags
> > > >> 
> > > >> Thanks for your report, looks this problem has existed over years.
> > > >> As a quick response, could you please try the below fix?
> > > > 
> > > > Thank you very much! This solved the problems with qemu.
> > > > 
> > > > I found a fiemap-tester util[1] in the xfstests project and it runs
> > 
> > fine
> > 
> > > > on
> > > > OCFS2 with 4K cluster size but fails with 1M. I have however no idea
> > > > if
> > > > this is a severe problem.
> > > > 
> > > > # gcc -DHAVE_FALLOCATE=1 -o fiemap-tester fiemap-tester.c
> > > > # ./fiemap-tester /mnt/kvm-images/fiemap_test
> > > > Starting infinite run, if you don't see any output then its working
> > > > properly. HEY FS PERSON: your fs is weird.  I specifically wanted a
> > > > hole and you allocated a block anyway.  FIBMAP confirms that
> > > > you allocated a block, and the block is filled with 0's so
> > > > everything is kosher, but you still allocated a block when
> > > > didn't need to.  This may or may not be what you wanted,
> > > > which is why I'm only printing this message once, in case
> > > > you didn't do it on purpose. This was at block 0.
> > 
> > > > ERROR: preallocated extent is not marked with FIEMAP_EXTENT_UNWRITTEN:
> > 0
> > 
> > > > map is
> > 
> > 'HDHPHHDDHPHPHPHDDHHPPDDPPPHHHPDDDPDHHHHDDDPPHPPPDPHHPPDPPHHDDPDPPHDHPDDDD
> > 
> > PDPPDPHDDPPDDPPHDDPDHHHDDPDHPHPDPPDDHPHPPHDPHPHDDHDPDPDHDHPDDPHPPPHDPPDPDD
> > 
> > HPHDDPPHPDHPPHPPHPHHPHDHPPDDPHDHHPPHPPDHPHPHDHPPDDDDPHHHPPPHHHDDDDPDPDDPPP
> > 
> > HPHDPPPHDPDPHDDHPPPDPDHPHHPHDHHDHPDPHDDPPHDPPDDPDDPPDHPPDPDHHPHDHPPHDDHDPH
> > 
> > > > PPPDHPDDDHDDHDPPHHDDPPDPDDHDHHPHDPHHPPPDPPDHDHHPPHDPHDPPHDPHHPPP'
> > 
> > logical:
> > > > [       0..     255] phys: 132160512..132160767 flags: 0x000 tot: 256
> > > > 
> > > > 
> > > > [1]
> > 
> > http://oss.sgi.com/cgi-bin/gitweb.cgi?p=xfs/cmds/xfstests.git;a=blob_plai
> > 
> > > > n;f=src/fiemap-tester.c;hb=HEAD>
> > > > 
> > > >> From: Jie Liu <jeff.liu@oracle.com>
> > > >> 
> > > >> Call fiemap ioctl(2) with given start offset as well as an desired
> > > >> mapping range should show extents if possible.  However, we calculate
> > > >> the end offset of mapping via 'mapping_end -= cpos' before iterating
> > > >> the extent records which would cause problems, e.g,
> > > >> 
> > > >> Cluster size 4096:
> > > >> debugfs.ocfs2 1.6.3
> > > >> 
> > > >>        Block Size Bits: 12   Cluster Size Bits: 12
> > > >> 
> > > >> The extended fiemap test utility From David:
> > > >> https://gist.github.com/anonymous/6172331
> > > >> 
> > > >> # dd if=/dev/urandom of=/ocfs2/test_file bs=1M count=1000
> > > >> # ./fiemap /ocfs2/test_file 4096 10
> > > >> start: 4096, length: 10
> > > >> File /ocfs2/test_file has 0 extents:
> > > >> #    Logical          Physical         Length           Flags
> > > >> 
> > > >>    ^^^^^ <-- No extents
> > > >> 
> > > >> In this case, at ocfs2_fiemap(): cpos == mapping_end == 1. Hence the
> > > >> loop of searching extent records was not executed at all.
> > > >> 
> > > >> This patch remove the in question 'mapping_end -= cpos', and loops
> > > >> until the cpos is larger than the mapping_end instead.
> > > >> 
> > > >> # ./fiemap /ocfs2/test_file 4096 10
> > > >> start: 4096, length: 10
> > > >> File /ocfs2/test_file has 1 extents:
> > > >> #    Logical          Physical         Length           Flags
> > > >> 0:    0000000000000000 0000000056a01000 0000000006a00000 0000
> > > >> 
> > > >> Reported-by: David Weber <wb@munzinger.de>
> > > >> Cc: Mark Fashen <mfasheh@suse.de>
> > > >> Cc: Joel Becker <jlbec@evilplan.org>
> > > >> Signed-off-by: Jie Liu <jeff.liu@oracle.com>
> > > >> ---
> > > >> fs/ocfs2/extent_map.c |    1 -
> > > >> 1 file changed, 1 deletion(-)
> > > >> 
> > > >> diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c
> > > >> index 2487116..8460647 100644
> > > >> --- a/fs/ocfs2/extent_map.c
> > > >> +++ b/fs/ocfs2/extent_map.c
> > > >> @@ -781,7 +781,6 @@ int ocfs2_fiemap(struct inode *inode, struct
> > > >> fiemap_extent_info *fieinfo, cpos = map_start >>
> > 
> > osb->s_clustersize_bits;
> > 
> > > >>    mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
> > > >>    
> > > >>                           map_start + map_len);
> > > >> 
> > > >> -    mapping_end -= cpos;
> > > >> 
> > > >>    is_last = 0;
> > > >>    while (cpos < mapping_end && !is_last) {
> > > >>    
> > > >>        u32 fe_flags;
> > > >>> 
> > > >>> We're running linux-3.11-rc4 plus the following patches:
> > > >>> [PATCH V2] ocfs2: update inode size after zeroed the hole
> > > >>> [PATCH RESEND] ocfs2: fix NULL pointer dereference in
> > > >>> ocfs2_duplicate_clusters_by_page
> > > >>> NULL pointer dereference at    ocfs2_dir_foreach_blk_id
> > > >>> [patch v3] ocfs2: ocfs2: fix recent memory corruption bug
> > > >>> 
> > > >>> o2info --volinfo  /dev/drbd0
> > > >>> 
> > > >>>       Label: kvm-images
> > > >>>       
> > > >>>        UUID: BE7C101466AD4F2196A849C7A6031263
> > > >>>  
> > > >>>  Block Size: 4096
> > > >>> 
> > > >>> Cluster Size: 1048576
> > > >>> 
> > > >>>  Node Slots: 8
> > > >>>  
> > > >>>    Features: backup-super strict-journal-super sparse
> > 
> > extended-slotmap
> > 
> > > >>>    Features: inline-data xattr indexed-dirs refcount discontig-bg
> > > >>>    unwritten
> > > >>> 
> > > >>> Thanks in advance!
> > > >>> 
> > > >>> Cheers,
> > > >>> David
> > > >>> 
> > > >>> 
> > > >>> [1]
> > 
> > http://git.qemu.org/?p=qemu.git;a=blob;f=block/raw-posix.c;h=ba721d3f5bd
> > 
> > > >>> 9
> > > >>> 8a6b62791c2e20dbf2894021ad76;hb=HEAD#l1087
> > > >>> 
> > > >>> [2]
> > 
> > http://smackerelofopinion.blogspot.de/2010/01/using-fiemap-ioctl-to-get->
> > 
> > >>> f
> > >>> 
> > > >>> ile-extents.html
> > > >>> 
> > > >>> [3] https://gist.github.com/anonymous/6172331
> > > >>> 
> > > >>> 
> > > >>> _______________________________________________
> > > >>> Ocfs2-devel mailing list
> > > >>> Ocfs2-devel@oss.oracle.com
> > > >>> https://oss.oracle.com/mailman/listinfo/ocfs2-devel
> > > > 
> > > > _______________________________________________
> > > > Ocfs2-devel mailing list
> > > > Ocfs2-devel@oss.oracle.com
> > > > https://oss.oracle.com/mailman/listinfo/ocfs2-devel
jeff.liu Aug. 29, 2013, 8:39 a.m. UTC | #6
On 08/27/2013 04:18 PM, David Weber wrote:

> Am Donnerstag, 8. August 2013, 09:20:45 schrieb Sunil Mushran:
>> So it's a test issue. The utility assumes the fs allocates in 4K units.
>> That's why it only works when clustersize is 4K.
> 
> Thanks for the clarification!
> 
> The patch seems to have solved our problem. It would be great if it could be 
> pushed to Linux.

I'll resend this patch for the review.  Sorry for the late response as I
just back from a longer vacation.

Thanks,
-Jeff

> 
> Cheers,
> David
> 
>>
>> On Thu, Aug 8, 2013 at 8:09 AM, David Weber <wb@munzinger.de> wrote:
>>> Am Donnerstag, 8. August 2013, 07:30:27 schrieb Sunil Mushran:
>>>> Interesting. Please can you print the inode disk using the command
>>>> below.
>>>> The file path is minus the mounted dir.
>>>>
>>>> debugfs.ocfs2 -R "stat /relative/path/to/file" /dev/DEVICE
>>>>
>>>> It is saying that the fs has allocated a block when it did not need to.
>>>
>>> It
>>>
>>>> could be that the test utility does not handle blocks larger than 4K, or
>>>> the fiemap ioctl has a bug or the fs is indeed allocating a block when
>>>> it
>>>> does not need to. The above command will show us the actual layout on
>>>
>>> disk.
>>>
>>> Thank you for looking into this!
>>>
>>> # ./fiemap-tester /mnt/kvm-images/fiemap_new
>>> Starting infinite run, if you don't see any output then its working
>>> properly.
>>> HEY FS PERSON: your fs is weird.  I specifically wanted a
>>> hole and you allocated a block anyway.  FIBMAP confirms that
>>> you allocated a block, and the block is filled with 0's so
>>> everything is kosher, but you still allocated a block when
>>> didn't need to.  This may or may not be what you wanted,
>>> which is why I'm only printing this message once, in case
>>> you didn't do it on purpose. This was at block 0.
>>> ERROR: preallocated extent is not marked with FIEMAP_EXTENT_UNWRITTEN: 0
>>> map is
>>>
>>> 'HDHPHHDDHPHPHPHDDHHPPDDPPPHHHPDDDPDHHHHDDDPPHPPPDPHHPPDPPHHDDPDPPHDHPDDDD
>>> PDPPDPHDDPPDDPPHDDPDHHHDDPDHPHPDPPDDHPHPPHDPHPHDDHDPDPDHDHPDDPHPPPHDPPDPDD
>>> HPHDDPPHPDHPPHPPHPHHPHDHPPDDPHDHHPPHPPDHPHPHDHPPDDDDPHHHPPPHHHDDDDPDPDDPPP
>>> HPHDPPPHDPDPHDDHPPPDPDHPHHPHDHHDHPDPHDDPPHDPPDDPDDPPDHPPDPDHHPHDHPPHDDHDPH
>>> PPPDHPDDDHDDHDPPHHDDPPDPDDHDHHPHDPHHPPPDPPDHDHHPPHDPHDPPHDPHHPPP' logical:
>>> [       0..     255] phys: 206615552..206615807 flags: 0x000 tot: 256
>>> Problem comparing fiemap and map
>>>
>>> # debugfs.ocfs2 -R "stat /fiemap_new" /dev/drbd0
>>>
>>>         Inode: 92668161   Mode: 0644   Generation: 3713753505 (0xdd5b61a1)
>>>         FS Generation: 2357962590 (0x8c8ba75e)
>>>         CRC32: 00000000   ECC: 0000
>>>         Type: Regular   Attr: 0x0   Flags: Valid
>>>         Dynamic Features: (0x0)
>>>         User: 0 (root)   Group: 0 (root)   Size: 1470464
>>>         Links: 1   Clusters: 2
>>>         ctime: 0x5203b200 0x991cd -- Thu Aug  8 16:58:08.627149 2013
>>>         atime: 0x5203b200 0xc0accc -- Thu Aug  8 16:58:08.12627148 2013
>>>         mtime: 0x5203b200 0x991cd -- Thu Aug  8 16:58:08.627149 2013
>>>         dtime: 0x0 -- Thu Jan  1 01:00:00 1970
>>>         Refcount Block: 0
>>>         Last Extblk: 0   Orphan Slot: 0
>>>         Sub Alloc Slot: 0   Sub Alloc Bit: 1
>>>         Tree Depth: 0   Count: 243   Next Free Rec: 2
>>>         ## Offset        Clusters       Block#          Flags
>>>         0  0             1              206615552       0x0
>>>         1  1             1              206619648       0x0
>>>>
>>>> On Aug 8, 2013, at 2:16 AM, David Weber <wb@munzinger.de> wrote:
>>>>> Am Mittwoch, 7. August 2013, 22:07:19 schrieb Jeff Liu:
>>>>>> On 08/07/2013 05:17 PM, David Weber wrote:
>>>>>>> Hi,
>>>>>>>
>>>>>>> We are trying to use OCFS2 as VM storage. After running into
>>>>>>> problems
>>>>>>> with
>>>>>>> qemu's disk_mirror feature we now think there could be a problem
>>>>>>> with
>>>>>>> the
>>>>>>> FIEMAP ioctl in OCFS2.
>>>>>>>
>>>>>>> As far as I understand the situation looks like this:
>>>>>>> Qemu inquiries the FS if the given section of the image is already
>>>>>>> allocated via the FIEMAP ioctl [1]
>>>>>>> It especially checks if fm_mapped_extents is greater 0.
>>>>>>> OCFS2 reports on sections bigger 1048576 there would be 0
>>>
>>> mapped_extents
>>>
>>>>>>> which is wrong.
>>>>>>>
>>>>>>> I extended a userspace FIEMAP util [2] a bit to specify the start
>>>>>>> and
>>>>>>> length parameter [3] as an easier testcase.
>>>>>>>
>>>>>>> When we create a big file which has no holes
>>>>>>> dd if=/dev/urandom of=/mnt/kvm-images/urandom.img bs=1M count=1000
>>>>>>>
>>>>>>> We get on lower sections the expected output:
>>>>>>> ./a.out /mnt/kvm-images/urandom.img 10000 10
>>>>>>> start: 2710, length: a
>>>>>>> File /mnt/kvm-images/urandom.img has 1 extents:
>>>>>>> #       Logical          Physical         Length           Flags
>>>>>>> 0:      0000000000000000 0000004ca3f00000 000000000be00000 0000
>>>>>>>
>>>>>>> But on sections >= 1048576 it reports there wouldn't be any extents
>>>>>>> which
>>>>>>> is as far as I understand wrong:
>>>>>>> ./a.out /mnt/kvm-images/urandom.img 1048576 10
>>>>>>> start: 100000, length: a
>>>>>>> File /mnt/kvm-images/urandom.img has 0 extents:
>>>>>>> #       Logical          Physical         Length           Flags
>>>>>>
>>>>>> Thanks for your report, looks this problem has existed over years.
>>>>>> As a quick response, could you please try the below fix?
>>>>>
>>>>> Thank you very much! This solved the problems with qemu.
>>>>>
>>>>> I found a fiemap-tester util[1] in the xfstests project and it runs
>>>
>>> fine
>>>
>>>>> on
>>>>> OCFS2 with 4K cluster size but fails with 1M. I have however no idea
>>>>> if
>>>>> this is a severe problem.
>>>>>
>>>>> # gcc -DHAVE_FALLOCATE=1 -o fiemap-tester fiemap-tester.c
>>>>> # ./fiemap-tester /mnt/kvm-images/fiemap_test
>>>>> Starting infinite run, if you don't see any output then its working
>>>>> properly. HEY FS PERSON: your fs is weird.  I specifically wanted a
>>>>> hole and you allocated a block anyway.  FIBMAP confirms that
>>>>> you allocated a block, and the block is filled with 0's so
>>>>> everything is kosher, but you still allocated a block when
>>>>> didn't need to.  This may or may not be what you wanted,
>>>>> which is why I'm only printing this message once, in case
>>>>> you didn't do it on purpose. This was at block 0.
>>>
>>>>> ERROR: preallocated extent is not marked with FIEMAP_EXTENT_UNWRITTEN:
>>> 0
>>>
>>>>> map is
>>>
>>> 'HDHPHHDDHPHPHPHDDHHPPDDPPPHHHPDDDPDHHHHDDDPPHPPPDPHHPPDPPHHDDPDPPHDHPDDDD
>>>
>>> PDPPDPHDDPPDDPPHDDPDHHHDDPDHPHPDPPDDHPHPPHDPHPHDDHDPDPDHDHPDDPHPPPHDPPDPDD
>>>
>>> HPHDDPPHPDHPPHPPHPHHPHDHPPDDPHDHHPPHPPDHPHPHDHPPDDDDPHHHPPPHHHDDDDPDPDDPPP
>>>
>>> HPHDPPPHDPDPHDDHPPPDPDHPHHPHDHHDHPDPHDDPPHDPPDDPDDPPDHPPDPDHHPHDHPPHDDHDPH
>>>
>>>>> PPPDHPDDDHDDHDPPHHDDPPDPDDHDHHPHDPHHPPPDPPDHDHHPPHDPHDPPHDPHHPPP'
>>>
>>> logical:
>>>>> [       0..     255] phys: 132160512..132160767 flags: 0x000 tot: 256
>>>>>
>>>>>
>>>>> [1]
>>>
>>> http://oss.sgi.com/cgi-bin/gitweb.cgi?p=xfs/cmds/xfstests.git;a=blob_plai
>>>
>>>>> n;f=src/fiemap-tester.c;hb=HEAD>
>>>>>
>>>>>> From: Jie Liu <jeff.liu@oracle.com>
>>>>>>
>>>>>> Call fiemap ioctl(2) with given start offset as well as an desired
>>>>>> mapping range should show extents if possible.  However, we calculate
>>>>>> the end offset of mapping via 'mapping_end -= cpos' before iterating
>>>>>> the extent records which would cause problems, e.g,
>>>>>>
>>>>>> Cluster size 4096:
>>>>>> debugfs.ocfs2 1.6.3
>>>>>>
>>>>>>        Block Size Bits: 12   Cluster Size Bits: 12
>>>>>>
>>>>>> The extended fiemap test utility From David:
>>>>>> https://gist.github.com/anonymous/6172331
>>>>>>
>>>>>> # dd if=/dev/urandom of=/ocfs2/test_file bs=1M count=1000
>>>>>> # ./fiemap /ocfs2/test_file 4096 10
>>>>>> start: 4096, length: 10
>>>>>> File /ocfs2/test_file has 0 extents:
>>>>>> #    Logical          Physical         Length           Flags
>>>>>>
>>>>>>    ^^^^^ <-- No extents
>>>>>>
>>>>>> In this case, at ocfs2_fiemap(): cpos == mapping_end == 1. Hence the
>>>>>> loop of searching extent records was not executed at all.
>>>>>>
>>>>>> This patch remove the in question 'mapping_end -= cpos', and loops
>>>>>> until the cpos is larger than the mapping_end instead.
>>>>>>
>>>>>> # ./fiemap /ocfs2/test_file 4096 10
>>>>>> start: 4096, length: 10
>>>>>> File /ocfs2/test_file has 1 extents:
>>>>>> #    Logical          Physical         Length           Flags
>>>>>> 0:    0000000000000000 0000000056a01000 0000000006a00000 0000
>>>>>>
>>>>>> Reported-by: David Weber <wb@munzinger.de>
>>>>>> Cc: Mark Fashen <mfasheh@suse.de>
>>>>>> Cc: Joel Becker <jlbec@evilplan.org>
>>>>>> Signed-off-by: Jie Liu <jeff.liu@oracle.com>
>>>>>> ---
>>>>>> fs/ocfs2/extent_map.c |    1 -
>>>>>> 1 file changed, 1 deletion(-)
>>>>>>
>>>>>> diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c
>>>>>> index 2487116..8460647 100644
>>>>>> --- a/fs/ocfs2/extent_map.c
>>>>>> +++ b/fs/ocfs2/extent_map.c
>>>>>> @@ -781,7 +781,6 @@ int ocfs2_fiemap(struct inode *inode, struct
>>>>>> fiemap_extent_info *fieinfo, cpos = map_start >>
>>>
>>> osb->s_clustersize_bits;
>>>
>>>>>>    mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
>>>>>>    
>>>>>>                           map_start + map_len);
>>>>>>
>>>>>> -    mapping_end -= cpos;
>>>>>>
>>>>>>    is_last = 0;
>>>>>>    while (cpos < mapping_end && !is_last) {
>>>>>>    
>>>>>>        u32 fe_flags;
>>>>>>>
>>>>>>> We're running linux-3.11-rc4 plus the following patches:
>>>>>>> [PATCH V2] ocfs2: update inode size after zeroed the hole
>>>>>>> [PATCH RESEND] ocfs2: fix NULL pointer dereference in
>>>>>>> ocfs2_duplicate_clusters_by_page
>>>>>>> NULL pointer dereference at    ocfs2_dir_foreach_blk_id
>>>>>>> [patch v3] ocfs2: ocfs2: fix recent memory corruption bug
>>>>>>>
>>>>>>> o2info --volinfo  /dev/drbd0
>>>>>>>
>>>>>>>       Label: kvm-images
>>>>>>>       
>>>>>>>        UUID: BE7C101466AD4F2196A849C7A6031263
>>>>>>>  
>>>>>>>  Block Size: 4096
>>>>>>>
>>>>>>> Cluster Size: 1048576
>>>>>>>
>>>>>>>  Node Slots: 8
>>>>>>>  
>>>>>>>    Features: backup-super strict-journal-super sparse
>>>
>>> extended-slotmap
>>>
>>>>>>>    Features: inline-data xattr indexed-dirs refcount discontig-bg
>>>>>>>    unwritten
>>>>>>>
>>>>>>> Thanks in advance!
>>>>>>>
>>>>>>> Cheers,
>>>>>>> David
>>>>>>>
>>>>>>>
>>>>>>> [1]
>>>
>>> http://git.qemu.org/?p=qemu.git;a=blob;f=block/raw-posix.c;h=ba721d3f5bd
>>>
>>>>>>> 9
>>>>>>> 8a6b62791c2e20dbf2894021ad76;hb=HEAD#l1087
>>>>>>>
>>>>>>> [2]
>>>
>>> http://smackerelofopinion.blogspot.de/2010/01/using-fiemap-ioctl-to-get->
>>>
>>>>>> f
>>>>>>
>>>>>>> ile-extents.html
>>>>>>>
>>>>>>> [3] https://gist.github.com/anonymous/6172331
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Ocfs2-devel mailing list
>>>>>>> Ocfs2-devel@oss.oracle.com
>>>>>>> https://oss.oracle.com/mailman/listinfo/ocfs2-devel
>>>>>
>>>>> _______________________________________________
>>>>> Ocfs2-devel mailing list
>>>>> Ocfs2-devel@oss.oracle.com
>>>>> https://oss.oracle.com/mailman/listinfo/ocfs2-devel
>
diff mbox

Patch

diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c
index 2487116..8460647 100644
--- a/fs/ocfs2/extent_map.c
+++ b/fs/ocfs2/extent_map.c
@@ -781,7 +781,6 @@  int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 	cpos = map_start >> osb->s_clustersize_bits;
 	mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
 					       map_start + map_len);
-	mapping_end -= cpos;
 	is_last = 0;
 	while (cpos < mapping_end && !is_last) {
 		u32 fe_flags;