Patchwork [Ext4,punch,hole,5/6,v5] Ext4 Punch Hole Support: Map blocks punch hole flag

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Submitter Allison Henderson
Date April 19, 2011, 7:43 a.m.
Message ID <4DAD3D05.8000103@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/91928/
State Superseded
Headers show

Comments

Allison Henderson - April 19, 2011, 7:43 a.m.
This patch adds a new flag to map blocks that specifies
the given range of blocks should be punched out.  Extents
are first converted to uninitialized extents before they are
punched out. Because punching a hole may require that the
extent be split, it is possible that the splitting may need
more blocks than are available.  To deal with this, reserved
blocks are temporarily borrowed to allow the split to proceed.
The borrowed blocks are then returned after the hole punch has
released more blocks.

The routine then returns the number of blocks successfully
punched out.

Signed-off-by: Allison Henderson <achender@us.ibm.com>
---
:100644 100644 e3a721a... d97bc87... M	fs/ext4/extents.c
 fs/ext4/extents.c |   99 +++++++++++++++++++++++++++++++++++++++++++++++------
 1 files changed, 88 insertions(+), 11 deletions(-)
Yongqiang Yang - April 19, 2011, 8:35 a.m.
On Tue, Apr 19, 2011 at 3:43 PM, Allison Henderson
<achender@linux.vnet.ibm.com> wrote:
> This patch adds a new flag to map blocks that specifies
> the given range of blocks should be punched out.  Extents
> are first converted to uninitialized extents before they are
> punched out. Because punching a hole may require that the
> extent be split, it is possible that the splitting may need
> more blocks than are available.  To deal with this, reserved
> blocks are temporarily borrowed to allow the split to proceed.
> The borrowed blocks are then returned after the hole punch has
> released more blocks.
>
> The routine then returns the number of blocks successfully
> punched out.
>
> Signed-off-by: Allison Henderson <achender@us.ibm.com>
> ---
> :100644 100644 e3a721a... d97bc87... M  fs/ext4/extents.c
>  fs/ext4/extents.c |   99 +++++++++++++++++++++++++++++++++++++++++++++++------
>  1 files changed, 88 insertions(+), 11 deletions(-)
>
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index e3a721a..d97bc87 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -3456,15 +3456,19 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
>        ext4_fsblk_t newblock = 0;
>        int err = 0, depth, ret;
>        unsigned int allocated = 0;
> +       unsigned int punched_out = 0;
> +       unsigned int result = 0;
>        struct ext4_allocation_request ar;
>        ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
> +       struct ext4_map_blocks punch_map;
>
>        ext_debug("blocks %u/%u requested for inode %lu\n",
>                  map->m_lblk, map->m_len, inode->i_ino);
>        trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
>
>        /* check in cache */
> -       if (ext4_ext_in_cache(inode, map->m_lblk, &newex)) {
> +       if (ext4_ext_in_cache(inode, map->m_lblk, &newex) &&
> +               ((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0)) {
>                if (!newex.ee_start_lo && !newex.ee_start_hi) {
>                        if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
>                                /*
> @@ -3529,16 +3533,85 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
>                        ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
>                                  ee_block, ee_len, newblock);
>
> -                       /* Do not put uninitialized extent in the cache */
> -                       if (!ext4_ext_is_uninitialized(ex)) {
> -                               ext4_ext_put_in_cache(inode, ee_block,
> -                                                       ee_len, ee_start);
> -                               goto out;
> +                       if ((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0) {
> +                               /*
> +                                * Do not put uninitialized extent
> +                                * in the cache
> +                                */
> +                               if (!ext4_ext_is_uninitialized(ex)) {
> +                                       ext4_ext_put_in_cache(inode, ee_block,
> +                                               ee_len, ee_start);
> +                                       goto out;
> +                               }
> +                               ret = ext4_ext_handle_uninitialized_extents(
> +                                       handle, inode, map, path, flags,
> +                                       allocated, newblock);
> +                               return ret;
>                        }
> -                       ret = ext4_ext_handle_uninitialized_extents(handle,
> -                                       inode, map, path, flags, allocated,
> -                                       newblock);
> -                       return ret;
> +
> +                       /*
> +                        * Punch out the map length, but only to the
> +                        * end of the extent
> +                        */
> +                       punched_out = allocated < map->m_len ?
> +                               allocated : map->m_len;
> +
> +                       /*
> +                        * Sense extents need to be converted to
> +                        * uninitialized, they must fit in an
> +                        * uninitialized extent
> +                        */
> +                       if (punched_out > EXT_UNINIT_MAX_LEN)
> +                               punched_out = EXT_UNINIT_MAX_LEN;
> +
> +                       punch_map.m_lblk = map->m_lblk;
> +                       punch_map.m_pblk = newblock;
> +                       punch_map.m_len = punched_out;
> +                       punch_map.m_flags = 0;
> +
> +                       /* Check to see if the extent needs to be split */
> +                       if (punch_map.m_len != ee_len ||
> +                               punch_map.m_lblk != ee_block) {
> +
> +                               ret = ext4_ext_split_extents(handle, inode,
> +                               &punch_map, path,
> +                               EXT4_GET_BLOCKS_PRE_IO |
> +                               EXT4_HAS_FREE_BLKS_USE_ROOTBLKS,
> +                               0);
> +
> +                               if (ret < 0) {
> +                                       err = ret;
> +                                       goto out2;
> +                               }
> +                               /*
> +                                * find extent for the block at
> +                                * the start of the hole
> +                                */
> +                               ext4_ext_drop_refs(path);
> +                               kfree(path);
> +
> +                               path = ext4_ext_find_extent(inode,
> +                               map->m_lblk, NULL);
> +                               if (IS_ERR(path)) {
> +                                       err = PTR_ERR(path);
> +                                       path = NULL;
> +                                       goto out2;
> +                               }
> +
> +                               depth = ext_depth(inode);
> +                               ex = path[depth].p_ext;
> +                               ee_len = ext4_ext_get_actual_len(ex);
> +                               ee_block = le32_to_cpu(ex->ee_block);
> +                               ee_start = ext4_ext_pblock(ex);
> +
> +                       }
> +
> +                       ext4_ext_mark_uninitialized(ex);
Is this change journaled?

> +
> +                       err = ext4_ext_remove_space(inode, map->m_lblk,
> +                               map->m_lblk + punched_out);
> +
> +                       goto out2;
>                }
>        }
>
> @@ -3683,7 +3756,11 @@ out2:
>        }
>        trace_ext4_ext_map_blocks_exit(inode, map->m_lblk,
>                newblock, map->m_len, err ? err : allocated);
> -       return err ? err : allocated;
> +
> +       result = (flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) ?
> +                       punched_out : allocated;
> +
> +       return err ? err : result;
>  }
>
>  void ext4_ext_truncate(struct inode *inode)
> --
> 1.7.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
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>
Mingming Cao - April 19, 2011, 5:48 p.m.
On Tue, 2011-04-19 at 16:35 +0800, Yongqiang Yang wrote:
> On Tue, Apr 19, 2011 at 3:43 PM, Allison Henderson
> <achender@linux.vnet.ibm.com> wrote:
> > This patch adds a new flag to map blocks that specifies
> > the given range of blocks should be punched out.  Extents
> > are first converted to uninitialized extents before they are
> > punched out. Because punching a hole may require that the
> > extent be split, it is possible that the splitting may need
> > more blocks than are available.  To deal with this, reserved
> > blocks are temporarily borrowed to allow the split to proceed.
> > The borrowed blocks are then returned after the hole punch has
> > released more blocks.
> >
> > The routine then returns the number of blocks successfully
> > punched out.
> >
> > Signed-off-by: Allison Henderson <achender@us.ibm.com>
> > ---
> > :100644 100644 e3a721a... d97bc87... M  fs/ext4/extents.c
> >  fs/ext4/extents.c |   99 +++++++++++++++++++++++++++++++++++++++++++++++------
> >  1 files changed, 88 insertions(+), 11 deletions(-)
> >
> > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> > index e3a721a..d97bc87 100644
> > --- a/fs/ext4/extents.c
> > +++ b/fs/ext4/extents.c
> > @@ -3456,15 +3456,19 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
> >        ext4_fsblk_t newblock = 0;
> >        int err = 0, depth, ret;
> >        unsigned int allocated = 0;
> > +       unsigned int punched_out = 0;
> > +       unsigned int result = 0;
> >        struct ext4_allocation_request ar;
> >        ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
> > +       struct ext4_map_blocks punch_map;
> >
> >        ext_debug("blocks %u/%u requested for inode %lu\n",
> >                  map->m_lblk, map->m_len, inode->i_ino);
> >        trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
> >
> >        /* check in cache */
> > -       if (ext4_ext_in_cache(inode, map->m_lblk, &newex)) {
> > +       if (ext4_ext_in_cache(inode, map->m_lblk, &newex) &&
> > +               ((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0)) {
> >                if (!newex.ee_start_lo && !newex.ee_start_hi) {
> >                        if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
> >                                /*
> > @@ -3529,16 +3533,85 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
> >                        ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
> >                                  ee_block, ee_len, newblock);
> >
> > -                       /* Do not put uninitialized extent in the cache */
> > -                       if (!ext4_ext_is_uninitialized(ex)) {
> > -                               ext4_ext_put_in_cache(inode, ee_block,
> > -                                                       ee_len, ee_start);
> > -                               goto out;
> > +                       if ((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0) {
> > +                               /*
> > +                                * Do not put uninitialized extent
> > +                                * in the cache
> > +                                */
> > +                               if (!ext4_ext_is_uninitialized(ex)) {
> > +                                       ext4_ext_put_in_cache(inode, ee_block,
> > +                                               ee_len, ee_start);
> > +                                       goto out;
> > +                               }
> > +                               ret = ext4_ext_handle_uninitialized_extents(
> > +                                       handle, inode, map, path, flags,
> > +                                       allocated, newblock);
> > +                               return ret;
> >                        }
> > -                       ret = ext4_ext_handle_uninitialized_extents(handle,
> > -                                       inode, map, path, flags, allocated,
> > -                                       newblock);
> > -                       return ret;
> > +
> > +                       /*
> > +                        * Punch out the map length, but only to the
> > +                        * end of the extent
> > +                        */
> > +                       punched_out = allocated < map->m_len ?
> > +                               allocated : map->m_len;
> > +
> > +                       /*
> > +                        * Sense extents need to be converted to
> > +                        * uninitialized, they must fit in an
> > +                        * uninitialized extent
> > +                        */
> > +                       if (punched_out > EXT_UNINIT_MAX_LEN)
> > +                               punched_out = EXT_UNINIT_MAX_LEN;
> > +
> > +                       punch_map.m_lblk = map->m_lblk;
> > +                       punch_map.m_pblk = newblock;
> > +                       punch_map.m_len = punched_out;
> > +                       punch_map.m_flags = 0;
> > +
> > +                       /* Check to see if the extent needs to be split */
> > +                       if (punch_map.m_len != ee_len ||
> > +                               punch_map.m_lblk != ee_block) {
> > +
> > +                               ret = ext4_ext_split_extents(handle, inode,
> > +                               &punch_map, path,
> > +                               EXT4_GET_BLOCKS_PRE_IO |
> > +                               EXT4_HAS_FREE_BLKS_USE_ROOTBLKS,
> > +                               0);
> > +
> > +                               if (ret < 0) {
> > +                                       err = ret;
> > +                                       goto out2;
> > +                               }
> > +                               /*
> > +                                * find extent for the block at
> > +                                * the start of the hole
> > +                                */
> > +                               ext4_ext_drop_refs(path);
> > +                               kfree(path);
> > +
> > +                               path = ext4_ext_find_extent(inode,
> > +                               map->m_lblk, NULL);
> > +                               if (IS_ERR(path)) {
> > +                                       err = PTR_ERR(path);
> > +                                       path = NULL;
> > +                                       goto out2;
> > +                               }
> > +
> > +                               depth = ext_depth(inode);
> > +                               ex = path[depth].p_ext;
> > +                               ee_len = ext4_ext_get_actual_len(ex);
> > +                               ee_block = le32_to_cpu(ex->ee_block);
> > +                               ee_start = ext4_ext_pblock(ex);
> > +
> > +                       }
> > +
> > +                       ext4_ext_mark_uninitialized(ex);
> Is this change journaled?
> 

Looks like so, ext4_ext_map_blocks() takes journal handle as argument,
the ext4 punch hole code reserve the journal credits before calling
ext4_ext_map_blocks().


> > +
> > +                       err = ext4_ext_remove_space(inode, map->m_lblk,
> > +                               map->m_lblk + punched_out);
> > +
> > +                       goto out2;
> >                }
> >        }
> >
> > @@ -3683,7 +3756,11 @@ out2:
> >        }
> >        trace_ext4_ext_map_blocks_exit(inode, map->m_lblk,
> >                newblock, map->m_len, err ? err : allocated);
> > -       return err ? err : allocated;
> > +
> > +       result = (flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) ?
> > +                       punched_out : allocated;
> > +
> > +       return err ? err : result;
> >  }
> >
> >  void ext4_ext_truncate(struct inode *inode)
> > --
> > 1.7.1
> >
> > --
> > 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
> >
> 
> 
> 


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Allison Henderson - April 19, 2011, 5:48 p.m.
On 4/19/2011 1:35 AM, Yongqiang Yang wrote:
> On Tue, Apr 19, 2011 at 3:43 PM, Allison Henderson
> <achender@linux.vnet.ibm.com>  wrote:
>> This patch adds a new flag to map blocks that specifies
>> the given range of blocks should be punched out.  Extents
>> are first converted to uninitialized extents before they are
>> punched out. Because punching a hole may require that the
>> extent be split, it is possible that the splitting may need
>> more blocks than are available.  To deal with this, reserved
>> blocks are temporarily borrowed to allow the split to proceed.
>> The borrowed blocks are then returned after the hole punch has
>> released more blocks.
>>
>> The routine then returns the number of blocks successfully
>> punched out.
>>
>> Signed-off-by: Allison Henderson<achender@us.ibm.com>
>> ---
>> :100644 100644 e3a721a... d97bc87... M  fs/ext4/extents.c
>>   fs/ext4/extents.c |   99 +++++++++++++++++++++++++++++++++++++++++++++++------
>>   1 files changed, 88 insertions(+), 11 deletions(-)
>>
>> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
>> index e3a721a..d97bc87 100644
>> --- a/fs/ext4/extents.c
>> +++ b/fs/ext4/extents.c
>> @@ -3456,15 +3456,19 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
>>         ext4_fsblk_t newblock = 0;
>>         int err = 0, depth, ret;
>>         unsigned int allocated = 0;
>> +       unsigned int punched_out = 0;
>> +       unsigned int result = 0;
>>         struct ext4_allocation_request ar;
>>         ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
>> +       struct ext4_map_blocks punch_map;
>>
>>         ext_debug("blocks %u/%u requested for inode %lu\n",
>>                   map->m_lblk, map->m_len, inode->i_ino);
>>         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
>>
>>         /* check in cache */
>> -       if (ext4_ext_in_cache(inode, map->m_lblk,&newex)) {
>> +       if (ext4_ext_in_cache(inode, map->m_lblk,&newex)&&
>> +               ((flags&  EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0)) {
>>                 if (!newex.ee_start_lo&&  !newex.ee_start_hi) {
>>                         if ((flags&  EXT4_GET_BLOCKS_CREATE) == 0) {
>>                                 /*
>> @@ -3529,16 +3533,85 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
>>                         ext_debug("%u fit into %u:%d ->  %llu\n", map->m_lblk,
>>                                   ee_block, ee_len, newblock);
>>
>> -                       /* Do not put uninitialized extent in the cache */
>> -                       if (!ext4_ext_is_uninitialized(ex)) {
>> -                               ext4_ext_put_in_cache(inode, ee_block,
>> -                                                       ee_len, ee_start);
>> -                               goto out;
>> +                       if ((flags&  EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0) {
>> +                               /*
>> +                                * Do not put uninitialized extent
>> +                                * in the cache
>> +                                */
>> +                               if (!ext4_ext_is_uninitialized(ex)) {
>> +                                       ext4_ext_put_in_cache(inode, ee_block,
>> +                                               ee_len, ee_start);
>> +                                       goto out;
>> +                               }
>> +                               ret = ext4_ext_handle_uninitialized_extents(
>> +                                       handle, inode, map, path, flags,
>> +                                       allocated, newblock);
>> +                               return ret;
>>                         }
>> -                       ret = ext4_ext_handle_uninitialized_extents(handle,
>> -                                       inode, map, path, flags, allocated,
>> -                                       newblock);
>> -                       return ret;
>> +
>> +                       /*
>> +                        * Punch out the map length, but only to the
>> +                        * end of the extent
>> +                        */
>> +                       punched_out = allocated<  map->m_len ?
>> +                               allocated : map->m_len;
>> +
>> +                       /*
>> +                        * Sense extents need to be converted to
>> +                        * uninitialized, they must fit in an
>> +                        * uninitialized extent
>> +                        */
>> +                       if (punched_out>  EXT_UNINIT_MAX_LEN)
>> +                               punched_out = EXT_UNINIT_MAX_LEN;
>> +
>> +                       punch_map.m_lblk = map->m_lblk;
>> +                       punch_map.m_pblk = newblock;
>> +                       punch_map.m_len = punched_out;
>> +                       punch_map.m_flags = 0;
>> +
>> +                       /* Check to see if the extent needs to be split */
>> +                       if (punch_map.m_len != ee_len ||
>> +                               punch_map.m_lblk != ee_block) {
>> +
>> +                               ret = ext4_ext_split_extents(handle, inode,
>> +&punch_map, path,
>> +                               EXT4_GET_BLOCKS_PRE_IO |
>> +                               EXT4_HAS_FREE_BLKS_USE_ROOTBLKS,
>> +                               0);
>> +
>> +                               if (ret<  0) {
>> +                                       err = ret;
>> +                                       goto out2;
>> +                               }
>> +                               /*
>> +                                * find extent for the block at
>> +                                * the start of the hole
>> +                                */
>> +                               ext4_ext_drop_refs(path);
>> +                               kfree(path);
>> +
>> +                               path = ext4_ext_find_extent(inode,
>> +                               map->m_lblk, NULL);
>> +                               if (IS_ERR(path)) {
>> +                                       err = PTR_ERR(path);
>> +                                       path = NULL;
>> +                                       goto out2;
>> +                               }
>> +
>> +                               depth = ext_depth(inode);
>> +                               ex = path[depth].p_ext;
>> +                               ee_len = ext4_ext_get_actual_len(ex);
>> +                               ee_block = le32_to_cpu(ex->ee_block);
>> +                               ee_start = ext4_ext_pblock(ex);
>> +
>> +                       }
>> +
>> +                       ext4_ext_mark_uninitialized(ex);
> Is this change journaled?
Hi there, 

Yes, the ext4_ext_map_blocks routine requires a journal handle as a parameter, so the calling function is required to set up the journal.

> 
>> +
>> +                       err = ext4_ext_remove_space(inode, map->m_lblk,
>> +                               map->m_lblk + punched_out);
>> +
>> +                       goto out2;
>>                 }
>>         }
>>
>> @@ -3683,7 +3756,11 @@ out2:
>>         }
>>         trace_ext4_ext_map_blocks_exit(inode, map->m_lblk,
>>                 newblock, map->m_len, err ? err : allocated);
>> -       return err ? err : allocated;
>> +
>> +       result = (flags&  EXT4_GET_BLOCKS_PUNCH_OUT_EXT) ?
>> +                       punched_out : allocated;
>> +
>> +       return err ? err : result;
>>   }
>>
>>   void ext4_ext_truncate(struct inode *inode)
>> --
>> 1.7.1
>>
>> --
>> 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
>>
> 
> 
> 

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Patch

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index e3a721a..d97bc87 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3456,15 +3456,19 @@  int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
 	ext4_fsblk_t newblock = 0;
 	int err = 0, depth, ret;
 	unsigned int allocated = 0;
+	unsigned int punched_out = 0;
+	unsigned int result = 0;
 	struct ext4_allocation_request ar;
 	ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
+	struct ext4_map_blocks punch_map;
 
 	ext_debug("blocks %u/%u requested for inode %lu\n",
 		  map->m_lblk, map->m_len, inode->i_ino);
 	trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
 
 	/* check in cache */
-	if (ext4_ext_in_cache(inode, map->m_lblk, &newex)) {
+	if (ext4_ext_in_cache(inode, map->m_lblk, &newex) &&
+		((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0)) {
 		if (!newex.ee_start_lo && !newex.ee_start_hi) {
 			if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
 				/*
@@ -3529,16 +3533,85 @@  int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
 			ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
 				  ee_block, ee_len, newblock);
 
-			/* Do not put uninitialized extent in the cache */
-			if (!ext4_ext_is_uninitialized(ex)) {
-				ext4_ext_put_in_cache(inode, ee_block,
-							ee_len, ee_start);
-				goto out;
+			if ((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0) {
+				/*
+				 * Do not put uninitialized extent
+				 * in the cache
+				 */
+				if (!ext4_ext_is_uninitialized(ex)) {
+					ext4_ext_put_in_cache(inode, ee_block,
+						ee_len, ee_start);
+					goto out;
+				}
+				ret = ext4_ext_handle_uninitialized_extents(
+					handle, inode, map, path, flags,
+					allocated, newblock);
+				return ret;
 			}
-			ret = ext4_ext_handle_uninitialized_extents(handle,
-					inode, map, path, flags, allocated,
-					newblock);
-			return ret;
+
+			/*
+			 * Punch out the map length, but only to the
+			 * end of the extent
+			 */
+			punched_out = allocated < map->m_len ?
+				allocated : map->m_len;
+
+			/*
+			 * Sense extents need to be converted to
+			 * uninitialized, they must fit in an
+			 * uninitialized extent
+			 */
+			if (punched_out > EXT_UNINIT_MAX_LEN)
+				punched_out = EXT_UNINIT_MAX_LEN;
+
+			punch_map.m_lblk = map->m_lblk;
+			punch_map.m_pblk = newblock;
+			punch_map.m_len = punched_out;
+			punch_map.m_flags = 0;
+
+			/* Check to see if the extent needs to be split */
+			if (punch_map.m_len != ee_len ||
+				punch_map.m_lblk != ee_block) {
+
+				ret = ext4_ext_split_extents(handle, inode,
+				&punch_map, path,
+				EXT4_GET_BLOCKS_PRE_IO |
+				EXT4_HAS_FREE_BLKS_USE_ROOTBLKS,
+				0);
+
+				if (ret < 0) {
+					err = ret;
+					goto out2;
+				}
+				/*
+				 * find extent for the block at
+				 * the start of the hole
+				 */
+				ext4_ext_drop_refs(path);
+				kfree(path);
+
+				path = ext4_ext_find_extent(inode,
+				map->m_lblk, NULL);
+				if (IS_ERR(path)) {
+					err = PTR_ERR(path);
+					path = NULL;
+					goto out2;
+				}
+
+				depth = ext_depth(inode);
+				ex = path[depth].p_ext;
+				ee_len = ext4_ext_get_actual_len(ex);
+				ee_block = le32_to_cpu(ex->ee_block);
+				ee_start = ext4_ext_pblock(ex);
+
+			}
+
+			ext4_ext_mark_uninitialized(ex);
+
+			err = ext4_ext_remove_space(inode, map->m_lblk,
+				map->m_lblk + punched_out);
+
+			goto out2;
 		}
 	}
 
@@ -3683,7 +3756,11 @@  out2:
 	}
 	trace_ext4_ext_map_blocks_exit(inode, map->m_lblk,
 		newblock, map->m_len, err ? err : allocated);
-	return err ? err : allocated;
+
+	result = (flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) ?
+			punched_out : allocated;
+
+	return err ? err : result;
 }
 
 void ext4_ext_truncate(struct inode *inode)