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authorEric Sandeen <sandeen@redhat.com>2011-06-28 10:01:31 -0400
committerTheodore Ts'o <tytso@mit.edu>2011-06-28 10:01:31 -0400
commitf86186b44b4164600cce03d0d93ad48ec21fa429 (patch)
tree48aafabbbe46d22de84e4e9b3ebf7c5b35fd6d1e /fs/ext4/balloc.c
parentdae1e52cb1267bf8f52e5e47a80fab566d7e8aa4 (diff)
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. 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>
Diffstat (limited to 'fs/ext4/balloc.c')
-rw-r--r--fs/ext4/balloc.c48
1 files changed, 48 insertions, 0 deletions
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 264f6949511..f8224adf496 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;
+}
+