Patchwork [v2,1/3] ext4:Add a function merging extent right and left.

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Submitter Yongqiang Yang
Date May 3, 2011, 2:04 a.m.
Message ID <1304388301-9452-2-git-send-email-xiaoqiangnk@gmail.com>
Download mbox | patch
Permalink /patch/93735/
State Accepted
Headers show

Comments

Yongqiang Yang - May 3, 2011, 2:04 a.m.
1] Rename ext4_ext_try_to_merge() to ext4_ext_try_to_merge_right().

2] Add a new function ext4_ext_try_to_merge() which tries to merge
   an extent both left and right.

3] Use the new function in ext4_ext_convert_unwritten_endio() and
   ext4_ext_insert_extent().

Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Tested-by: Allison Henderson <achender@linux.vnet.ibm.com>
---
 fs/ext4/extents.c |   65 ++++++++++++++++++++++++++++------------------------
 1 files changed, 35 insertions(+), 30 deletions(-)
Mingming Cao - May 4, 2011, 12:03 a.m.
On Mon, 2011-05-02 at 19:04 -0700, Yongqiang Yang wrote:
> 1] Rename ext4_ext_try_to_merge() to ext4_ext_try_to_merge_right().
> 
> 2] Add a new function ext4_ext_try_to_merge() which tries to merge
>    an extent both left and right.
> 
> 3] Use the new function in ext4_ext_convert_unwritten_endio() and
>    ext4_ext_insert_extent().
> 
> Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
> Tested-by: Allison Henderson <achender@linux.vnet.ibm.com>

Looks good to me,

Reviewed-by: Mingming Cao <cmm@us.ibm.com>
> ---
>  fs/ext4/extents.c |   65 ++++++++++++++++++++++++++++------------------------
>  1 files changed, 35 insertions(+), 30 deletions(-)
> 
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index dd2cb50..11f30d2 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -1563,7 +1563,7 @@ ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
>   * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
>   * 1 if they got merged.
>   */
> -static int ext4_ext_try_to_merge(struct inode *inode,
> +static int ext4_ext_try_to_merge_right(struct inode *inode,
>  				 struct ext4_ext_path *path,
>  				 struct ext4_extent *ex)
>  {
> @@ -1603,6 +1603,31 @@ static int ext4_ext_try_to_merge(struct inode *inode,
>  }
> 
>  /*
> + * This function tries to merge the @ex extent to neighbours in the tree.
> + * return 1 if merge left else 0.
> + */
> +static int ext4_ext_try_to_merge(struct inode *inode,
> +				  struct ext4_ext_path *path,
> +				  struct ext4_extent *ex) {
> +	struct ext4_extent_header *eh;
> +	unsigned int depth;
> +	int merge_done = 0;
> +	int ret = 0;
> +
> +	depth = ext_depth(inode);
> +	BUG_ON(path[depth].p_hdr == NULL);
> +	eh = path[depth].p_hdr;
> +
> +	if (ex > EXT_FIRST_EXTENT(eh))
> +		merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
> +
> +	if (!merge_done)
> +		ret = ext4_ext_try_to_merge_right(inode, path, ex);
> +
> +	return ret;
> +}
> +
> +/*
>   * check if a portion of the "newext" extent overlaps with an
>   * existing extent.
>   *
> @@ -3039,6 +3064,7 @@ fix_extent_len:
>  	ext4_ext_dirty(handle, inode, path + depth);
>  	return err;
>  }
> +
>  static int ext4_convert_unwritten_extents_endio(handle_t *handle,
>  					      struct inode *inode,
>  					      struct ext4_ext_path *path)
> @@ -3047,46 +3073,25 @@ static int ext4_convert_unwritten_extents_endio(handle_t *handle,
>  	struct ext4_extent_header *eh;
>  	int depth;
>  	int err = 0;
> -	int ret = 0;
> 
>  	depth = ext_depth(inode);
>  	eh = path[depth].p_hdr;
>  	ex = path[depth].p_ext;
> 
> +	ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
> +		"block %llu, max_blocks %u\n", inode->i_ino,
> +		(unsigned long long)le32_to_cpu(ex->ee_block),
> +		ext4_ext_get_actual_len(ex));
> +
>  	err = ext4_ext_get_access(handle, inode, path + depth);
>  	if (err)
>  		goto out;
>  	/* first mark the extent as initialized */
>  	ext4_ext_mark_initialized(ex);
> 
> -	/*
> -	 * We have to see if it can be merged with the extent
> -	 * on the left.
> -	 */
> -	if (ex > EXT_FIRST_EXTENT(eh)) {
> -		/*
> -		 * To merge left, pass "ex - 1" to try_to_merge(),
> -		 * since it merges towards right _only_.
> -		 */
> -		ret = ext4_ext_try_to_merge(inode, path, ex - 1);
> -		if (ret) {
> -			err = ext4_ext_correct_indexes(handle, inode, path);
> -			if (err)
> -				goto out;
> -			depth = ext_depth(inode);
> -			ex--;
> -		}
> -	}
> -	/*
> -	 * Try to Merge towards right.
> -	 */
> -	ret = ext4_ext_try_to_merge(inode, path, ex);
> -	if (ret) {
> -		err = ext4_ext_correct_indexes(handle, inode, path);
> -		if (err)
> -			goto out;
> -		depth = ext_depth(inode);
> -	}
> +	/* correct indexes is nt needed becasue borders are not changed */
> +	ext4_ext_try_to_merge(inode, path, ex);
> +
>  	/* Mark modified extent as dirty */
>  	err = ext4_ext_dirty(handle, inode, path + depth);
>  out:


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Patch

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index dd2cb50..11f30d2 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -1563,7 +1563,7 @@  ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
  * 1 if they got merged.
  */
-static int ext4_ext_try_to_merge(struct inode *inode,
+static int ext4_ext_try_to_merge_right(struct inode *inode,
 				 struct ext4_ext_path *path,
 				 struct ext4_extent *ex)
 {
@@ -1603,6 +1603,31 @@  static int ext4_ext_try_to_merge(struct inode *inode,
 }
 
 /*
+ * This function tries to merge the @ex extent to neighbours in the tree.
+ * return 1 if merge left else 0.
+ */
+static int ext4_ext_try_to_merge(struct inode *inode,
+				  struct ext4_ext_path *path,
+				  struct ext4_extent *ex) {
+	struct ext4_extent_header *eh;
+	unsigned int depth;
+	int merge_done = 0;
+	int ret = 0;
+
+	depth = ext_depth(inode);
+	BUG_ON(path[depth].p_hdr == NULL);
+	eh = path[depth].p_hdr;
+
+	if (ex > EXT_FIRST_EXTENT(eh))
+		merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
+
+	if (!merge_done)
+		ret = ext4_ext_try_to_merge_right(inode, path, ex);
+
+	return ret;
+}
+
+/*
  * check if a portion of the "newext" extent overlaps with an
  * existing extent.
  *
@@ -3039,6 +3064,7 @@  fix_extent_len:
 	ext4_ext_dirty(handle, inode, path + depth);
 	return err;
 }
+
 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
 					      struct inode *inode,
 					      struct ext4_ext_path *path)
@@ -3047,46 +3073,25 @@  static int ext4_convert_unwritten_extents_endio(handle_t *handle,
 	struct ext4_extent_header *eh;
 	int depth;
 	int err = 0;
-	int ret = 0;
 
 	depth = ext_depth(inode);
 	eh = path[depth].p_hdr;
 	ex = path[depth].p_ext;
 
+	ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
+		"block %llu, max_blocks %u\n", inode->i_ino,
+		(unsigned long long)le32_to_cpu(ex->ee_block),
+		ext4_ext_get_actual_len(ex));
+
 	err = ext4_ext_get_access(handle, inode, path + depth);
 	if (err)
 		goto out;
 	/* first mark the extent as initialized */
 	ext4_ext_mark_initialized(ex);
 
-	/*
-	 * We have to see if it can be merged with the extent
-	 * on the left.
-	 */
-	if (ex > EXT_FIRST_EXTENT(eh)) {
-		/*
-		 * To merge left, pass "ex - 1" to try_to_merge(),
-		 * since it merges towards right _only_.
-		 */
-		ret = ext4_ext_try_to_merge(inode, path, ex - 1);
-		if (ret) {
-			err = ext4_ext_correct_indexes(handle, inode, path);
-			if (err)
-				goto out;
-			depth = ext_depth(inode);
-			ex--;
-		}
-	}
-	/*
-	 * Try to Merge towards right.
-	 */
-	ret = ext4_ext_try_to_merge(inode, path, ex);
-	if (ret) {
-		err = ext4_ext_correct_indexes(handle, inode, path);
-		if (err)
-			goto out;
-		depth = ext_depth(inode);
-	}
+	/* correct indexes is nt needed becasue borders are not changed */
+	ext4_ext_try_to_merge(inode, path, ex);
+
 	/* Mark modified extent as dirty */
 	err = ext4_ext_dirty(handle, inode, path + depth);
 out: