ext4: refactor duplicated block placement code

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.

Signed-off-by Eric Sandeen <[email protected]>

---

ext4.h    |    1 
extents.c |   37 ---------------------------------
inode.c   |   69 +++++++++++++++++++++++++++++++++++++-------------------------
3 files changed, 44 insertions(+), 63 deletions(-)

I don't know that I like the new function name too much, I'm open to suggestions...

fs/ext4/ext4.h +1 -0

index 1921392..1d79fbc 100644
@@ -1812,6 +1812,7 @@ extern int  ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
 				struct kstat *stat);
 extern void ext4_evict_inode(struct inode *);
 extern void ext4_clear_inode(struct inode *);
+ext4_fsblk_t ext4_inode_group_start(struct inode *);
 extern int  ext4_sync_inode(handle_t *, struct inode *);
 extern void ext4_dirty_inode(struct inode *, int);
 extern int ext4_change_inode_journal_flag(struct inode *, int);

fs/ext4/extents.c +1 -36

index 5199bac..23cf7dd 100644
@@ -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_group_start(inode);
 }
 
 /*

fs/ext4/inode.c +42 -28

index a5763e3..5784809 100644
@@ -466,6 +466,47 @@ no_block:
 	return p;
 }
 
+ext4_fsblk_t ext4_inode_group_start(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;
+}
+
 /**
 *	ext4_find_near - find a place for allocation with sufficient locality
 *	@inode: owner

@@ -491,11 +532,6 @@ 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--) {

@@ -511,28 +547,7 @@ 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_group_start(inode);
 }
 
 /**
--

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Quoted 15 lines · Eric Sandeen

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.

Signed-off-by Eric Sandeen <[email protected]>

---

ext4.h    |    1 
extents.c |   37 ---------------------------------
inode.c   |   69 +++++++++++++++++++++++++++++++++++++-------------------------
3 files changed, 44 insertions(+), 63 deletions(-)

Quoted 2 lines

I don't know that I like the new function name too much, I'm open to suggestions...

What about ext4_goal_block_from_inode() or ext4_start_block_from_inode() or ext4_inode_to_{goal,start}_block()? One of last ones might be good since it makes it clear this function is related to other ext4_inode_*() functions.

Quoted 162 lines

fs/ext4/ext4.h +1 -0

index 1921392..1d79fbc 100644
@@ -1812,6 +1812,7 @@ extern int  ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
 				struct kstat *stat);
 extern void ext4_evict_inode(struct inode *);
 extern void ext4_clear_inode(struct inode *);
+ext4_fsblk_t ext4_inode_group_start(struct inode *);
 extern int  ext4_sync_inode(handle_t *, struct inode *);
 extern void ext4_dirty_inode(struct inode *, int);
 extern int ext4_change_inode_journal_flag(struct inode *, int);

fs/ext4/extents.c +1 -36

index 5199bac..23cf7dd 100644
@@ -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_group_start(inode);
 }
 
 /*

fs/ext4/inode.c +42 -28

index a5763e3..5784809 100644
@@ -466,6 +466,47 @@ no_block:
 	return p;
 }
 
+ext4_fsblk_t ext4_inode_group_start(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;
+}
+
 /**
 *	ext4_find_near - find a place for allocation with sufficient locality
 *	@inode: owner

@@ -491,11 +532,6 @@ 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--) {

@@ -511,28 +547,7 @@ 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_group_start(inode);
 }
 
 /**
--

Quoted 3 lines

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Cheers, Andreas

From: "Theodore Ts'o" <[email protected]>

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 <[email protected]>

Signed-off-by "Theodore Ts'o" <[email protected]>

---

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(-)

fs/ext4/balloc.c +48 -0

index 264f694..f8224ad 100644
@@ -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;
+}
+

fs/ext4/ext4.h +1 -0

index ddaf504..49d2cea 100644
@@ -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 *,

fs/ext4/extents.c +1 -36

index eb63c7b..f331e50 100644
@@ -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);
 }
 
 /*

fs/ext4/indirect.c +1 -27

index c3e85a8..6c27111 100644
@@ -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);
 }
 
 /**

Quoted 1 line · Theodore Ts'o

From: "Theodore Ts'o" <[email protected]>

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

Quoted 5 lines · Eric Sandeen

Quoted 1 line · Theodore Ts'o

From: "Theodore Ts'o" <[email protected]>

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