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authorTheodore Ts'o <tytso@mit.edu>2009-03-12 19:18:34 +0300
committerTheodore Ts'o <tytso@mit.edu>2009-03-12 19:18:34 +0300
commita4912123b688e057084e6557cef8924f7ae5bbde (patch)
tree34e88705d6617b52caa0f87692b480119a9c9e2e /fs/ext4/extents.c
parent2dc6b0d48ca0599837df21b14bb8393d0804af57 (diff)
downloadlinux-a4912123b688e057084e6557cef8924f7ae5bbde.tar.xz
ext4: New inode/block allocation algorithms for flex_bg filesystems
The find_group_flex() inode allocator is now only used if the filesystem is mounted using the "oldalloc" mount option. It is replaced with the original Orlov allocator that has been updated for flex_bg filesystems (it should behave the same way if flex_bg is disabled). The inode allocator now functions by taking into account each flex_bg group, instead of each block group, when deciding whether or not it's time to allocate a new directory into a fresh flex_bg. The block allocator has also been changed so that the first block group in each flex_bg is preferred for use for storing directory blocks. This keeps directory blocks close together, which is good for speeding up e2fsck since large directories are more likely to look like this: debugfs: stat /home/tytso/Maildir/cur Inode: 1844562 Type: directory Mode: 0700 Flags: 0x81000 Generation: 1132745781 Version: 0x00000000:0000ad71 User: 15806 Group: 15806 Size: 1060864 File ACL: 0 Directory ACL: 0 Links: 2 Blockcount: 2072 Fragment: Address: 0 Number: 0 Size: 0 ctime: 0x499c0ff4:164961f4 -- Wed Feb 18 08:41:08 2009 atime: 0x499c0ff4:00000000 -- Wed Feb 18 08:41:08 2009 mtime: 0x49957f51:00000000 -- Fri Feb 13 09:10:25 2009 crtime: 0x499c0f57:00d51440 -- Wed Feb 18 08:38:31 2009 Size of extra inode fields: 28 BLOCKS: (0):7348651, (1-258):7348654-7348911 TOTAL: 259 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/extents.c')
-rw-r--r--fs/ext4/extents.c25
1 files changed, 24 insertions, 1 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index e0aa4fe4f596..aa3431856c9a 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -152,6 +152,8 @@ static ext4_fsblk_t ext4_ext_find_goal(struct inode *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) {
@@ -170,10 +172,31 @@ static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
}
/* OK. use inode's group */
- bg_start = (ei->i_block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) +
+ 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 = (block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) +
le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_first_data_block);
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);