diff mbox series

[RFC,2/2] ext4: Move ext4_fiemap to iomap infrastructure

Message ID 20190820130634.25954-3-riteshh@linux.ibm.com
State New
Headers show
Series ext4: bmap & fiemap conversion to use iomap | expand

Commit Message

Ritesh Harjani Aug. 20, 2019, 1:06 p.m. UTC
This moves ext4_fiemap to use iomap infrastructure.

Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
---
 fs/ext4/extents.c | 294 +++++++---------------------------------------
 fs/ext4/inline.c  |  41 -------
 fs/ext4/inode.c   |  15 ++-
 3 files changed, 52 insertions(+), 298 deletions(-)

Comments

Jan Kara Oct. 16, 2019, 8:46 a.m. UTC | #1
On Tue 20-08-19 18:36:34, Ritesh Harjani wrote:
> This moves ext4_fiemap to use iomap infrastructure.
> 
> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>

Thanks for the patch. I like how it removes lots of code :) The patch looks
good to me, just two small comments below. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

> +static int ext4_xattr_iomap_fiemap(struct inode *inode, struct iomap *iomap)
>  {
> -	__u64 physical = 0;
> -	__u64 length;
> -	__u32 flags = FIEMAP_EXTENT_LAST;
> +	u64 physical = 0;
> +	u64 length;
>  	int blockbits = inode->i_sb->s_blocksize_bits;
> -	int error = 0;
> +	int ret = 0;
>  
>  	/* in-inode? */
>  	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
>  		struct ext4_iloc iloc;
> -		int offset;	/* offset of xattr in inode */
> +		int offset;     /* offset of xattr in inode */
>  
> -		error = ext4_get_inode_loc(inode, &iloc);
> -		if (error)
> -			return error;
> +		ret = ext4_get_inode_loc(inode, &iloc);
> +		if (ret)
> +			goto out;
>  		physical = (__u64)iloc.bh->b_blocknr << blockbits;
>  		offset = EXT4_GOOD_OLD_INODE_SIZE +
>  				EXT4_I(inode)->i_extra_isize;

Hum, I see you've just copied this from the old code but this actually
won't give full information for FIEMAP of inode with extended attribute
inodes. Not something you need to fix for your patch but I wanted to
mention this so that it doesn't get lost.

>  		physical += offset;
>  		length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
> -		flags |= FIEMAP_EXTENT_DATA_INLINE;
>  		brelse(iloc.bh);
>  	} else { /* external block */
>  		physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
>  		length = inode->i_sb->s_blocksize;
>  	}
>  
> -	if (physical)
> -		error = fiemap_fill_next_extent(fieinfo, 0, physical,
> -						length, flags);
> -	return (error < 0 ? error : 0);
> +	iomap->addr = physical;
> +	iomap->offset = 0;
> +	iomap->length = length;
> +	iomap->type = IOMAP_INLINE;
> +	iomap->flags = 0;
> +out:
> +	return ret;
>  }

...

> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index d6a34214e9df..92705e99e07c 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -3581,15 +3581,24 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
>  		iomap->type = delalloc ? IOMAP_DELALLOC : IOMAP_HOLE;
>  		iomap->addr = IOMAP_NULL_ADDR;
>  	} else {
> -		if (map.m_flags & EXT4_MAP_MAPPED) {
> -			iomap->type = IOMAP_MAPPED;
> -		} else if (map.m_flags & EXT4_MAP_UNWRITTEN) {
> +		/*
> +		 * There can be a case where map.m_flags may
> +		 * have both EXT4_MAP_UNWRITTEN & EXT4_MAP_MERGED
> +		 * set. This is when we do fallocate first and
> +		 * then try to write to that area, then it may have
> +		 * both flags set. So check for unwritten first.
> +		 */
> +		if (map.m_flags & EXT4_MAP_UNWRITTEN) {
>  			iomap->type = IOMAP_UNWRITTEN;
> +		} else if (map.m_flags & EXT4_MAP_MAPPED) {
> +			iomap->type = IOMAP_MAPPED;

This should be already part of Matthew's series so once you rebase on top
of it, you can just drop this hunk.

								Honza
Ritesh Harjani Oct. 16, 2019, 12:58 p.m. UTC | #2
On 10/16/19 2:16 PM, Jan Kara wrote:
> On Tue 20-08-19 18:36:34, Ritesh Harjani wrote:
>> This moves ext4_fiemap to use iomap infrastructure.
>>
>> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
> 
> Thanks for the patch. I like how it removes lots of code :) The patch looks
> good to me, just two small comments below. Feel free to add:
> 
> Reviewed-by: Jan Kara <jack@suse.cz>

Sure, thanks. It's been some quite some time.
Let me rebase these patches on latest upstream kernel.

> 
>> +static int ext4_xattr_iomap_fiemap(struct inode *inode, struct iomap *iomap)
>>   {
>> -	__u64 physical = 0;
>> -	__u64 length;
>> -	__u32 flags = FIEMAP_EXTENT_LAST;
>> +	u64 physical = 0;
>> +	u64 length;
>>   	int blockbits = inode->i_sb->s_blocksize_bits;
>> -	int error = 0;
>> +	int ret = 0;
>>   
>>   	/* in-inode? */
>>   	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
>>   		struct ext4_iloc iloc;
>> -		int offset;	/* offset of xattr in inode */
>> +		int offset;     /* offset of xattr in inode */
>>   
>> -		error = ext4_get_inode_loc(inode, &iloc);
>> -		if (error)
>> -			return error;
>> +		ret = ext4_get_inode_loc(inode, &iloc);
>> +		if (ret)
>> +			goto out;
>>   		physical = (__u64)iloc.bh->b_blocknr << blockbits;
>>   		offset = EXT4_GOOD_OLD_INODE_SIZE +
>>   				EXT4_I(inode)->i_extra_isize;
> 
> Hum, I see you've just copied this from the old code but this actually
> won't give full information for FIEMAP of inode with extended attribute
> inodes. 

Could you please elaborate on above? I am anyway taking a look at it in
parallel. I can provide that as a separate patch, if required.


> Not something you need to fix for your patch but I wanted to
> mention this so that it doesn't get lost.

Sure :)

> 
>>   		physical += offset;
>>   		length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
>> -		flags |= FIEMAP_EXTENT_DATA_INLINE;
>>   		brelse(iloc.bh);
>>   	} else { /* external block */
>>   		physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
>>   		length = inode->i_sb->s_blocksize;
>>   	}
>>   
>> -	if (physical)
>> -		error = fiemap_fill_next_extent(fieinfo, 0, physical,
>> -						length, flags);
>> -	return (error < 0 ? error : 0);
>> +	iomap->addr = physical;
>> +	iomap->offset = 0;
>> +	iomap->length = length;
>> +	iomap->type = IOMAP_INLINE;
>> +	iomap->flags = 0;
>> +out:
>> +	return ret;
>>   }
> 
> ...
> 
>> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
>> index d6a34214e9df..92705e99e07c 100644
>> --- a/fs/ext4/inode.c
>> +++ b/fs/ext4/inode.c
>> @@ -3581,15 +3581,24 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
>>   		iomap->type = delalloc ? IOMAP_DELALLOC : IOMAP_HOLE;
>>   		iomap->addr = IOMAP_NULL_ADDR;
>>   	} else {
>> -		if (map.m_flags & EXT4_MAP_MAPPED) {
>> -			iomap->type = IOMAP_MAPPED;
>> -		} else if (map.m_flags & EXT4_MAP_UNWRITTEN) {
>> +		/*
>> +		 * There can be a case where map.m_flags may
>> +		 * have both EXT4_MAP_UNWRITTEN & EXT4_MAP_MERGED
>> +		 * set. This is when we do fallocate first and
>> +		 * then try to write to that area, then it may have
>> +		 * both flags set. So check for unwritten first.
>> +		 */
>> +		if (map.m_flags & EXT4_MAP_UNWRITTEN) {
>>   			iomap->type = IOMAP_UNWRITTEN;
>> +		} else if (map.m_flags & EXT4_MAP_MAPPED) {
>> +			iomap->type = IOMAP_MAPPED;
> 
> This should be already part of Matthew's series so once you rebase on top
> of it, you can just drop this hunk.

Sure, will do.

-riteshh
diff mbox series

Patch

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 92266a2da7d6..a03e14e50085 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -28,6 +28,7 @@ 
 #include <linux/uaccess.h>
 #include <linux/fiemap.h>
 #include <linux/backing-dev.h>
+#include <linux/iomap.h>
 #include "ext4_jbd2.h"
 #include "ext4_extents.h"
 #include "xattr.h"
@@ -97,9 +98,6 @@  static int ext4_split_extent_at(handle_t *handle,
 			     int split_flag,
 			     int flags);
 
-static int ext4_find_delayed_extent(struct inode *inode,
-				    struct extent_status *newes);
-
 static int ext4_ext_truncate_extend_restart(handle_t *handle,
 					    struct inode *inode,
 					    int needed)
@@ -2166,155 +2164,6 @@  int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
 	return err;
 }
 
-static int ext4_fill_fiemap_extents(struct inode *inode,
-				    ext4_lblk_t block, ext4_lblk_t num,
-				    struct fiemap_extent_info *fieinfo)
-{
-	struct ext4_ext_path *path = NULL;
-	struct ext4_extent *ex;
-	struct extent_status es;
-	ext4_lblk_t next, next_del, start = 0, end = 0;
-	ext4_lblk_t last = block + num;
-	int exists, depth = 0, err = 0;
-	unsigned int flags = 0;
-	unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
-
-	while (block < last && block != EXT_MAX_BLOCKS) {
-		num = last - block;
-		/* find extent for this block */
-		down_read(&EXT4_I(inode)->i_data_sem);
-
-		path = ext4_find_extent(inode, block, &path, 0);
-		if (IS_ERR(path)) {
-			up_read(&EXT4_I(inode)->i_data_sem);
-			err = PTR_ERR(path);
-			path = NULL;
-			break;
-		}
-
-		depth = ext_depth(inode);
-		if (unlikely(path[depth].p_hdr == NULL)) {
-			up_read(&EXT4_I(inode)->i_data_sem);
-			EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
-			err = -EFSCORRUPTED;
-			break;
-		}
-		ex = path[depth].p_ext;
-		next = ext4_ext_next_allocated_block(path);
-
-		flags = 0;
-		exists = 0;
-		if (!ex) {
-			/* there is no extent yet, so try to allocate
-			 * all requested space */
-			start = block;
-			end = block + num;
-		} else if (le32_to_cpu(ex->ee_block) > block) {
-			/* need to allocate space before found extent */
-			start = block;
-			end = le32_to_cpu(ex->ee_block);
-			if (block + num < end)
-				end = block + num;
-		} else if (block >= le32_to_cpu(ex->ee_block)
-					+ ext4_ext_get_actual_len(ex)) {
-			/* need to allocate space after found extent */
-			start = block;
-			end = block + num;
-			if (end >= next)
-				end = next;
-		} else if (block >= le32_to_cpu(ex->ee_block)) {
-			/*
-			 * some part of requested space is covered
-			 * by found extent
-			 */
-			start = block;
-			end = le32_to_cpu(ex->ee_block)
-				+ ext4_ext_get_actual_len(ex);
-			if (block + num < end)
-				end = block + num;
-			exists = 1;
-		} else {
-			BUG();
-		}
-		BUG_ON(end <= start);
-
-		if (!exists) {
-			es.es_lblk = start;
-			es.es_len = end - start;
-			es.es_pblk = 0;
-		} else {
-			es.es_lblk = le32_to_cpu(ex->ee_block);
-			es.es_len = ext4_ext_get_actual_len(ex);
-			es.es_pblk = ext4_ext_pblock(ex);
-			if (ext4_ext_is_unwritten(ex))
-				flags |= FIEMAP_EXTENT_UNWRITTEN;
-		}
-
-		/*
-		 * Find delayed extent and update es accordingly. We call
-		 * it even in !exists case to find out whether es is the
-		 * last existing extent or not.
-		 */
-		next_del = ext4_find_delayed_extent(inode, &es);
-		if (!exists && next_del) {
-			exists = 1;
-			flags |= (FIEMAP_EXTENT_DELALLOC |
-				  FIEMAP_EXTENT_UNKNOWN);
-		}
-		up_read(&EXT4_I(inode)->i_data_sem);
-
-		if (unlikely(es.es_len == 0)) {
-			EXT4_ERROR_INODE(inode, "es.es_len == 0");
-			err = -EFSCORRUPTED;
-			break;
-		}
-
-		/*
-		 * This is possible iff next == next_del == EXT_MAX_BLOCKS.
-		 * we need to check next == EXT_MAX_BLOCKS because it is
-		 * possible that an extent is with unwritten and delayed
-		 * status due to when an extent is delayed allocated and
-		 * is allocated by fallocate status tree will track both of
-		 * them in a extent.
-		 *
-		 * So we could return a unwritten and delayed extent, and
-		 * its block is equal to 'next'.
-		 */
-		if (next == next_del && next == EXT_MAX_BLOCKS) {
-			flags |= FIEMAP_EXTENT_LAST;
-			if (unlikely(next_del != EXT_MAX_BLOCKS ||
-				     next != EXT_MAX_BLOCKS)) {
-				EXT4_ERROR_INODE(inode,
-						 "next extent == %u, next "
-						 "delalloc extent = %u",
-						 next, next_del);
-				err = -EFSCORRUPTED;
-				break;
-			}
-		}
-
-		if (exists) {
-			err = fiemap_fill_next_extent(fieinfo,
-				(__u64)es.es_lblk << blksize_bits,
-				(__u64)es.es_pblk << blksize_bits,
-				(__u64)es.es_len << blksize_bits,
-				flags);
-			if (err < 0)
-				break;
-			if (err == 1) {
-				err = 0;
-				break;
-			}
-		}
-
-		block = es.es_lblk + es.es_len;
-	}
-
-	ext4_ext_drop_refs(path);
-	kfree(path);
-	return err;
-}
-
 /*
  * ext4_ext_determine_hole - determine hole around given block
  * @inode:	inode we lookup in
@@ -4968,143 +4817,80 @@  int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
 	return ret > 0 ? ret2 : ret;
 }
 
-/*
- * If newes is not existing extent (newes->ec_pblk equals zero) find
- * delayed extent at start of newes and update newes accordingly and
- * return start of the next delayed extent.
- *
- * If newes is existing extent (newes->ec_pblk is not equal zero)
- * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
- * extent found. Leave newes unmodified.
- */
-static int ext4_find_delayed_extent(struct inode *inode,
-				    struct extent_status *newes)
-{
-	struct extent_status es;
-	ext4_lblk_t block, next_del;
-
-	if (newes->es_pblk == 0) {
-		ext4_es_find_extent_range(inode, &ext4_es_is_delayed,
-					  newes->es_lblk,
-					  newes->es_lblk + newes->es_len - 1,
-					  &es);
-
-		/*
-		 * No extent in extent-tree contains block @newes->es_pblk,
-		 * then the block may stay in 1)a hole or 2)delayed-extent.
-		 */
-		if (es.es_len == 0)
-			/* A hole found. */
-			return 0;
-
-		if (es.es_lblk > newes->es_lblk) {
-			/* A hole found. */
-			newes->es_len = min(es.es_lblk - newes->es_lblk,
-					    newes->es_len);
-			return 0;
-		}
-
-		newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
-	}
-
-	block = newes->es_lblk + newes->es_len;
-	ext4_es_find_extent_range(inode, &ext4_es_is_delayed, block,
-				  EXT_MAX_BLOCKS, &es);
-	if (es.es_len == 0)
-		next_del = EXT_MAX_BLOCKS;
-	else
-		next_del = es.es_lblk;
-
-	return next_del;
-}
 /* fiemap flags we can handle specified here */
 #define EXT4_FIEMAP_FLAGS	(FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
 
-static int ext4_xattr_fiemap(struct inode *inode,
-				struct fiemap_extent_info *fieinfo)
+static int ext4_xattr_iomap_fiemap(struct inode *inode, struct iomap *iomap)
 {
-	__u64 physical = 0;
-	__u64 length;
-	__u32 flags = FIEMAP_EXTENT_LAST;
+	u64 physical = 0;
+	u64 length;
 	int blockbits = inode->i_sb->s_blocksize_bits;
-	int error = 0;
+	int ret = 0;
 
 	/* in-inode? */
 	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 		struct ext4_iloc iloc;
-		int offset;	/* offset of xattr in inode */
+		int offset;     /* offset of xattr in inode */
 
-		error = ext4_get_inode_loc(inode, &iloc);
-		if (error)
-			return error;
+		ret = ext4_get_inode_loc(inode, &iloc);
+		if (ret)
+			goto out;
 		physical = (__u64)iloc.bh->b_blocknr << blockbits;
 		offset = EXT4_GOOD_OLD_INODE_SIZE +
 				EXT4_I(inode)->i_extra_isize;
 		physical += offset;
 		length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
-		flags |= FIEMAP_EXTENT_DATA_INLINE;
 		brelse(iloc.bh);
 	} else { /* external block */
 		physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
 		length = inode->i_sb->s_blocksize;
 	}
 
-	if (physical)
-		error = fiemap_fill_next_extent(fieinfo, 0, physical,
-						length, flags);
-	return (error < 0 ? error : 0);
+	iomap->addr = physical;
+	iomap->offset = 0;
+	iomap->length = length;
+	iomap->type = IOMAP_INLINE;
+	iomap->flags = 0;
+out:
+	return ret;
 }
 
-int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
-		__u64 start, __u64 len)
+static int ext4_xattr_iomap_begin(struct inode *inode, loff_t offset,
+				  loff_t length, unsigned flags,
+				  struct iomap *iomap)
 {
-	ext4_lblk_t start_blk;
-	int error = 0;
-
-	if (ext4_has_inline_data(inode)) {
-		int has_inline = 1;
+	int ret;
 
-		error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline,
-						start, len);
+	ret = ext4_xattr_iomap_fiemap(inode, iomap);
+	if (ret == 0 && (offset >= iomap->length))
+		ret = -ENOENT;
+	return ret;
+}
 
-		if (has_inline)
-			return error;
-	}
+const struct iomap_ops ext4_xattr_iomap_ops = {
+	.iomap_begin		= ext4_xattr_iomap_begin,
+};
 
+int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
+		u64 start, u64 length)
+{
+	int ret;
 	if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
-		error = ext4_ext_precache(inode);
-		if (error)
-			return error;
+		ret = ext4_ext_precache(inode);
+		if (ret)
+			return ret;
 	}
 
-	/* fallback to generic here if not in extents fmt */
-	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
-		return generic_block_fiemap(inode, fieinfo, start, len,
-			ext4_get_block);
-
 	if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
 		return -EBADR;
 
 	if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
-		error = ext4_xattr_fiemap(inode, fieinfo);
-	} else {
-		ext4_lblk_t len_blks;
-		__u64 last_blk;
-
-		start_blk = start >> inode->i_sb->s_blocksize_bits;
-		last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
-		if (last_blk >= EXT_MAX_BLOCKS)
-			last_blk = EXT_MAX_BLOCKS-1;
-		len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
-
-		/*
-		 * Walk the extent tree gathering extent information
-		 * and pushing extents back to the user.
-		 */
-		error = ext4_fill_fiemap_extents(inode, start_blk,
-						 len_blks, fieinfo);
+		fieinfo->fi_flags &= ~FIEMAP_FLAG_XATTR;
+		return iomap_fiemap(inode, fieinfo, start, length,
+				&ext4_xattr_iomap_ops);
 	}
-	return error;
+
+	return iomap_fiemap(inode, fieinfo, start, length, &ext4_iomap_ops);
 }
 
 /*
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 88cdf3c90bd1..1e22f3f798de 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -1855,47 +1855,6 @@  int ext4_inline_data_iomap(struct inode *inode, struct iomap *iomap)
 	return error;
 }
 
-int ext4_inline_data_fiemap(struct inode *inode,
-			    struct fiemap_extent_info *fieinfo,
-			    int *has_inline, __u64 start, __u64 len)
-{
-	__u64 physical = 0;
-	__u64 inline_len;
-	__u32 flags = FIEMAP_EXTENT_DATA_INLINE | FIEMAP_EXTENT_NOT_ALIGNED |
-		FIEMAP_EXTENT_LAST;
-	int error = 0;
-	struct ext4_iloc iloc;
-
-	down_read(&EXT4_I(inode)->xattr_sem);
-	if (!ext4_has_inline_data(inode)) {
-		*has_inline = 0;
-		goto out;
-	}
-	inline_len = min_t(size_t, ext4_get_inline_size(inode),
-			   i_size_read(inode));
-	if (start >= inline_len)
-		goto out;
-	if (start + len < inline_len)
-		inline_len = start + len;
-	inline_len -= start;
-
-	error = ext4_get_inode_loc(inode, &iloc);
-	if (error)
-		goto out;
-
-	physical = (__u64)iloc.bh->b_blocknr << inode->i_sb->s_blocksize_bits;
-	physical += (char *)ext4_raw_inode(&iloc) - iloc.bh->b_data;
-	physical += offsetof(struct ext4_inode, i_block);
-
-	brelse(iloc.bh);
-out:
-	up_read(&EXT4_I(inode)->xattr_sem);
-	if (physical)
-		error = fiemap_fill_next_extent(fieinfo, start, physical,
-						inline_len, flags);
-	return (error < 0 ? error : 0);
-}
-
 int ext4_inline_data_truncate(struct inode *inode, int *has_inline)
 {
 	handle_t *handle;
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index d6a34214e9df..92705e99e07c 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3581,15 +3581,24 @@  static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 		iomap->type = delalloc ? IOMAP_DELALLOC : IOMAP_HOLE;
 		iomap->addr = IOMAP_NULL_ADDR;
 	} else {
-		if (map.m_flags & EXT4_MAP_MAPPED) {
-			iomap->type = IOMAP_MAPPED;
-		} else if (map.m_flags & EXT4_MAP_UNWRITTEN) {
+		/*
+		 * There can be a case where map.m_flags may
+		 * have both EXT4_MAP_UNWRITTEN & EXT4_MAP_MERGED
+		 * set. This is when we do fallocate first and
+		 * then try to write to that area, then it may have
+		 * both flags set. So check for unwritten first.
+		 */
+		if (map.m_flags & EXT4_MAP_UNWRITTEN) {
 			iomap->type = IOMAP_UNWRITTEN;
+		} else if (map.m_flags & EXT4_MAP_MAPPED) {
+			iomap->type = IOMAP_MAPPED;
 		} else {
 			WARN_ON_ONCE(1);
 			return -EIO;
 		}
 		iomap->addr = (u64)map.m_pblk << blkbits;
+		if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+			iomap->flags |= IOMAP_F_MERGED;
 	}
 
 	if (map.m_flags & EXT4_MAP_NEW)