Patchwork [-v3] ext4: refactor duplicated block placement code

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Submitter Theodore Ts'o
Date June 28, 2011, 2:05 p.m.
Message ID <1309269909-15341-1-git-send-email-tytso@mit.edu>
Download mbox | patch
Permalink /patch/102388/
State Accepted
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Comments

Theodore Ts'o - June 28, 2011, 2:05 p.m.
From: "Theodore Ts'o" <tytso@mit.edu>

I found that ext4_ext_find_goal() and ext4_find_near()
share the same code for returning a coloured start block
based on i_block_group.

We can refactor this into a common function so that they
don't diverge in the future.

Thanks to adilger for suggesting the new function name.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---

Moved new code to balloc.c, and rebased patch to take into account the
fs/ext4/indirect.c reorganization.  -- Ted

 fs/ext4/balloc.c   |   48 ++++++++++++++++++++++++++++++++++++++++++++++++
 fs/ext4/ext4.h     |    1 +
 fs/ext4/extents.c  |   37 +------------------------------------
 fs/ext4/indirect.c |   28 +---------------------------
 4 files changed, 51 insertions(+), 63 deletions(-)
Eric Sandeen - June 28, 2011, 2:14 p.m.
On 6/28/11 9:05 AM, Theodore Ts'o wrote:
> From: "Theodore Ts'o" <tytso@mit.edu>

I kind of wish you'd keep me on the From: even if you did
move the change to a new file.

Thanks,
-Eric

> I found that ext4_ext_find_goal() and ext4_find_near()
> share the same code for returning a coloured start block
> based on i_block_group.
> 
> We can refactor this into a common function so that they
> don't diverge in the future.
> 
> Thanks to adilger for suggesting the new function name.
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
> ---
> 
> Moved new code to balloc.c, and rebased patch to take into account the
> fs/ext4/indirect.c reorganization.  -- Ted
> 
>  fs/ext4/balloc.c   |   48 ++++++++++++++++++++++++++++++++++++++++++++++++
>  fs/ext4/ext4.h     |    1 +
>  fs/ext4/extents.c  |   37 +------------------------------------
>  fs/ext4/indirect.c |   28 +---------------------------
>  4 files changed, 51 insertions(+), 63 deletions(-)
> 
> diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
> index 264f694..f8224ad 100644
> --- a/fs/ext4/balloc.c
> +++ b/fs/ext4/balloc.c
> @@ -620,3 +620,51 @@ unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group)
>  
>  }
>  
> +/**
> + *	ext4_inode_to_goal_block - return a hint for block allocation
> + *	@inode: inode for block allocation
> + *
> + *	Return the ideal location to start allocating blocks for a
> + *	newly created inode.
> + */
> +ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode)
> +{
> +	struct ext4_inode_info *ei = EXT4_I(inode);
> +	ext4_group_t block_group;
> +	ext4_grpblk_t colour;
> +	int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
> +	ext4_fsblk_t bg_start;
> +	ext4_fsblk_t last_block;
> +
> +	block_group = ei->i_block_group;
> +	if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
> +		/*
> +		 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
> +		 * block groups per flexgroup, reserve the first block
> +		 * group for directories and special files.  Regular
> +		 * files will start at the second block group.  This
> +		 * tends to speed up directory access and improves
> +		 * fsck times.
> +		 */
> +		block_group &= ~(flex_size-1);
> +		if (S_ISREG(inode->i_mode))
> +			block_group++;
> +	}
> +	bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
> +	last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
> +
> +	/*
> +	 * If we are doing delayed allocation, we don't need take
> +	 * colour into account.
> +	 */
> +	if (test_opt(inode->i_sb, DELALLOC))
> +		return bg_start;
> +
> +	if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
> +		colour = (current->pid % 16) *
> +			(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
> +	else
> +		colour = (current->pid % 16) * ((last_block - bg_start) / 16);
> +	return bg_start + colour;
> +}
> +
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index ddaf504..49d2cea 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -1743,6 +1743,7 @@ extern unsigned ext4_init_block_bitmap(struct super_block *sb,
>  				       struct ext4_group_desc *desc);
>  #define ext4_free_blocks_after_init(sb, group, desc)			\
>  		ext4_init_block_bitmap(sb, NULL, group, desc)
> +ext4_fsblk_t ext4_inode_to_goal_block(struct inode *);
>  
>  /* dir.c */
>  extern int __ext4_check_dir_entry(const char *, unsigned int, struct inode *,
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index eb63c7b..f331e50 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -114,12 +114,6 @@ static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
>  			      struct ext4_ext_path *path,
>  			      ext4_lblk_t block)
>  {
> -	struct ext4_inode_info *ei = EXT4_I(inode);
> -	ext4_fsblk_t bg_start;
> -	ext4_fsblk_t last_block;
> -	ext4_grpblk_t colour;
> -	ext4_group_t block_group;
> -	int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
>  	int depth;
>  
>  	if (path) {
> @@ -161,36 +155,7 @@ static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
>  	}
>  
>  	/* OK. use inode's group */
> -	block_group = ei->i_block_group;
> -	if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
> -		/*
> -		 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
> -		 * block groups per flexgroup, reserve the first block
> -		 * group for directories and special files.  Regular
> -		 * files will start at the second block group.  This
> -		 * tends to speed up directory access and improves
> -		 * fsck times.
> -		 */
> -		block_group &= ~(flex_size-1);
> -		if (S_ISREG(inode->i_mode))
> -			block_group++;
> -	}
> -	bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
> -	last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
> -
> -	/*
> -	 * If we are doing delayed allocation, we don't need take
> -	 * colour into account.
> -	 */
> -	if (test_opt(inode->i_sb, DELALLOC))
> -		return bg_start;
> -
> -	if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
> -		colour = (current->pid % 16) *
> -			(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
> -	else
> -		colour = (current->pid % 16) * ((last_block - bg_start) / 16);
> -	return bg_start + colour + block;
> +	return ext4_inode_to_goal_block(inode);
>  }
>  
>  /*
> diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
> index c3e85a8..6c27111 100644
> --- a/fs/ext4/indirect.c
> +++ b/fs/ext4/indirect.c
> @@ -207,11 +207,6 @@ static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
>  	struct ext4_inode_info *ei = EXT4_I(inode);
>  	__le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
>  	__le32 *p;
> -	ext4_fsblk_t bg_start;
> -	ext4_fsblk_t last_block;
> -	ext4_grpblk_t colour;
> -	ext4_group_t block_group;
> -	int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
>  
>  	/* Try to find previous block */
>  	for (p = ind->p - 1; p >= start; p--) {
> @@ -227,28 +222,7 @@ static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
>  	 * It is going to be referred to from the inode itself? OK, just put it
>  	 * into the same cylinder group then.
>  	 */
> -	block_group = ei->i_block_group;
> -	if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
> -		block_group &= ~(flex_size-1);
> -		if (S_ISREG(inode->i_mode))
> -			block_group++;
> -	}
> -	bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
> -	last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
> -
> -	/*
> -	 * If we are doing delayed allocation, we don't need take
> -	 * colour into account.
> -	 */
> -	if (test_opt(inode->i_sb, DELALLOC))
> -		return bg_start;
> -
> -	if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
> -		colour = (current->pid % 16) *
> -			(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
> -	else
> -		colour = (current->pid % 16) * ((last_block - bg_start) / 16);
> -	return bg_start + colour;
> +	return ext4_inode_to_goal_block(inode);
>  }
>  
>  /**

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Theodore Ts'o - June 28, 2011, 2:44 p.m.
On Tue, Jun 28, 2011 at 09:14:32AM -0500, Eric Sandeen wrote:
> On 6/28/11 9:05 AM, Theodore Ts'o wrote:
> > From: "Theodore Ts'o" <tytso@mit.edu>
> 
> I kind of wish you'd keep me on the From: even if you did
> move the change to a new file.

No worries, you are still the author in the git commit.

The From that you saw was becasue because I edited the output of
git-format-patch before I used git send-email, forgetting that git
send-email would fix up the from field and move the original From
field into the budy of the message.

					- Ted
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Eric Sandeen - June 28, 2011, 2:45 p.m.
On 6/28/11 9:44 AM, Ted Ts'o wrote:
> On Tue, Jun 28, 2011 at 09:14:32AM -0500, Eric Sandeen wrote:
>> On 6/28/11 9:05 AM, Theodore Ts'o wrote:
>>> From: "Theodore Ts'o" <tytso@mit.edu>
>>
>> I kind of wish you'd keep me on the From: even if you did
>> move the change to a new file.
> 
> No worries, you are still the author in the git commit.
> 
> The From that you saw was becasue because I edited the output of
> git-format-patch before I used git send-email, forgetting that git
> send-email would fix up the from field and move the original From
> field into the budy of the message.
> 
> 					- Ted

Thanks, just checking; when I import something with From: into guilt,
that sets the author.

-Eric
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Patch

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 264f694..f8224ad 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -620,3 +620,51 @@  unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group)
 
 }
 
+/**
+ *	ext4_inode_to_goal_block - return a hint for block allocation
+ *	@inode: inode for block allocation
+ *
+ *	Return the ideal location to start allocating blocks for a
+ *	newly created inode.
+ */
+ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	ext4_group_t block_group;
+	ext4_grpblk_t colour;
+	int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
+	ext4_fsblk_t bg_start;
+	ext4_fsblk_t last_block;
+
+	block_group = ei->i_block_group;
+	if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
+		/*
+		 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
+		 * block groups per flexgroup, reserve the first block
+		 * group for directories and special files.  Regular
+		 * files will start at the second block group.  This
+		 * tends to speed up directory access and improves
+		 * fsck times.
+		 */
+		block_group &= ~(flex_size-1);
+		if (S_ISREG(inode->i_mode))
+			block_group++;
+	}
+	bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
+	last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
+
+	/*
+	 * If we are doing delayed allocation, we don't need take
+	 * colour into account.
+	 */
+	if (test_opt(inode->i_sb, DELALLOC))
+		return bg_start;
+
+	if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
+		colour = (current->pid % 16) *
+			(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
+	else
+		colour = (current->pid % 16) * ((last_block - bg_start) / 16);
+	return bg_start + colour;
+}
+
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index ddaf504..49d2cea 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1743,6 +1743,7 @@  extern unsigned ext4_init_block_bitmap(struct super_block *sb,
 				       struct ext4_group_desc *desc);
 #define ext4_free_blocks_after_init(sb, group, desc)			\
 		ext4_init_block_bitmap(sb, NULL, group, desc)
+ext4_fsblk_t ext4_inode_to_goal_block(struct inode *);
 
 /* dir.c */
 extern int __ext4_check_dir_entry(const char *, unsigned int, struct inode *,
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index eb63c7b..f331e50 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -114,12 +114,6 @@  static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 			      struct ext4_ext_path *path,
 			      ext4_lblk_t block)
 {
-	struct ext4_inode_info *ei = EXT4_I(inode);
-	ext4_fsblk_t bg_start;
-	ext4_fsblk_t last_block;
-	ext4_grpblk_t colour;
-	ext4_group_t block_group;
-	int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
 	int depth;
 
 	if (path) {
@@ -161,36 +155,7 @@  static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 	}
 
 	/* OK. use inode's group */
-	block_group = ei->i_block_group;
-	if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
-		/*
-		 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
-		 * block groups per flexgroup, reserve the first block
-		 * group for directories and special files.  Regular
-		 * files will start at the second block group.  This
-		 * tends to speed up directory access and improves
-		 * fsck times.
-		 */
-		block_group &= ~(flex_size-1);
-		if (S_ISREG(inode->i_mode))
-			block_group++;
-	}
-	bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
-	last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
-
-	/*
-	 * If we are doing delayed allocation, we don't need take
-	 * colour into account.
-	 */
-	if (test_opt(inode->i_sb, DELALLOC))
-		return bg_start;
-
-	if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
-		colour = (current->pid % 16) *
-			(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
-	else
-		colour = (current->pid % 16) * ((last_block - bg_start) / 16);
-	return bg_start + colour + block;
+	return ext4_inode_to_goal_block(inode);
 }
 
 /*
diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index c3e85a8..6c27111 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -207,11 +207,6 @@  static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
 	struct ext4_inode_info *ei = EXT4_I(inode);
 	__le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
 	__le32 *p;
-	ext4_fsblk_t bg_start;
-	ext4_fsblk_t last_block;
-	ext4_grpblk_t colour;
-	ext4_group_t block_group;
-	int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
 
 	/* Try to find previous block */
 	for (p = ind->p - 1; p >= start; p--) {
@@ -227,28 +222,7 @@  static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
 	 * It is going to be referred to from the inode itself? OK, just put it
 	 * into the same cylinder group then.
 	 */
-	block_group = ei->i_block_group;
-	if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
-		block_group &= ~(flex_size-1);
-		if (S_ISREG(inode->i_mode))
-			block_group++;
-	}
-	bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
-	last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
-
-	/*
-	 * If we are doing delayed allocation, we don't need take
-	 * colour into account.
-	 */
-	if (test_opt(inode->i_sb, DELALLOC))
-		return bg_start;
-
-	if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
-		colour = (current->pid % 16) *
-			(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
-	else
-		colour = (current->pid % 16) * ((last_block - bg_start) / 16);
-	return bg_start + colour;
+	return ext4_inode_to_goal_block(inode);
 }
 
 /**