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author | Eric Sandeen <sandeen@redhat.com> | 2011-06-28 14:01:31 (GMT) |
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committer | Theodore Ts'o <tytso@mit.edu> | 2011-06-28 14:01:31 (GMT) |
commit | f86186b44b4164600cce03d0d93ad48ec21fa429 (patch) | |
tree | 48aafabbbe46d22de84e4e9b3ebf7c5b35fd6d1e /fs/ext4/balloc.c | |
parent | dae1e52cb1267bf8f52e5e47a80fab566d7e8aa4 (diff) | |
download | linux-f86186b44b4164600cce03d0d93ad48ec21fa429.tar.xz |
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.c | 48 |
1 files changed, 48 insertions, 0 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; +} + |