ext4: Add percpu dirty block accounting.
This patch adds dirty block accounting using percpu_counters. Delayed
allocation block reservation is now done by updating dirty block
counter. In a later patch we switch to non delalloc mode if the
filesystem free blocks is greater than 150% of total filesystem dirty
blocks
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Mingming Cao<cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 5790988..edef002 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -1605,26 +1605,38 @@
int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
ext4_fsblk_t nblocks)
{
- s64 free_blocks;
+ s64 free_blocks, dirty_blocks;
ext4_fsblk_t root_blocks = 0;
struct percpu_counter *fbc = &sbi->s_freeblocks_counter;
+ struct percpu_counter *dbc = &sbi->s_dirtyblocks_counter;
- free_blocks = percpu_counter_read(fbc);
+ free_blocks = percpu_counter_read_positive(fbc);
+ dirty_blocks = percpu_counter_read_positive(dbc);
if (!capable(CAP_SYS_RESOURCE) &&
sbi->s_resuid != current->fsuid &&
(sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid)))
root_blocks = ext4_r_blocks_count(sbi->s_es);
- if (free_blocks - (nblocks + root_blocks) < EXT4_FREEBLOCKS_WATERMARK)
- free_blocks = percpu_counter_sum(&sbi->s_freeblocks_counter);
-
- if (free_blocks < (root_blocks + nblocks))
+ if (free_blocks - (nblocks + root_blocks + dirty_blocks) <
+ EXT4_FREEBLOCKS_WATERMARK) {
+ free_blocks = percpu_counter_sum(fbc);
+ dirty_blocks = percpu_counter_sum(dbc);
+ if (dirty_blocks < 0) {
+ printk(KERN_CRIT "Dirty block accounting "
+ "went wrong %lld\n",
+ dirty_blocks);
+ }
+ }
+ /* Check whether we have space after
+ * accounting for current dirty blocks
+ */
+ if (free_blocks < ((s64)(root_blocks + nblocks) + dirty_blocks))
/* we don't have free space */
return -ENOSPC;
- /* reduce fs free blocks counter */
- percpu_counter_sub(fbc, nblocks);
+ /* Add the blocks to nblocks */
+ percpu_counter_add(dbc, nblocks);
return 0;
}
@@ -1640,23 +1652,28 @@
ext4_fsblk_t ext4_has_free_blocks(struct ext4_sb_info *sbi,
ext4_fsblk_t nblocks)
{
- ext4_fsblk_t free_blocks;
+ ext4_fsblk_t free_blocks, dirty_blocks;
ext4_fsblk_t root_blocks = 0;
+ struct percpu_counter *fbc = &sbi->s_freeblocks_counter;
+ struct percpu_counter *dbc = &sbi->s_dirtyblocks_counter;
- free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
+ free_blocks = percpu_counter_read_positive(fbc);
+ dirty_blocks = percpu_counter_read_positive(dbc);
if (!capable(CAP_SYS_RESOURCE) &&
sbi->s_resuid != current->fsuid &&
(sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid)))
root_blocks = ext4_r_blocks_count(sbi->s_es);
- if (free_blocks - (nblocks + root_blocks) < EXT4_FREEBLOCKS_WATERMARK)
- free_blocks = percpu_counter_sum_positive(&sbi->s_freeblocks_counter);
-
- if (free_blocks <= root_blocks)
+ if (free_blocks - (nblocks + root_blocks + dirty_blocks) <
+ EXT4_FREEBLOCKS_WATERMARK) {
+ free_blocks = percpu_counter_sum_positive(fbc);
+ dirty_blocks = percpu_counter_sum_positive(dbc);
+ }
+ if (free_blocks <= (root_blocks + dirty_blocks))
/* we don't have free space */
return 0;
- if (free_blocks - root_blocks < nblocks)
+ if (free_blocks - (root_blocks + dirty_blocks) < nblocks)
return free_blocks - root_blocks;
return nblocks;
}
@@ -1943,13 +1960,14 @@
le16_add_cpu(&gdp->bg_free_blocks_count, -num);
gdp->bg_checksum = ext4_group_desc_csum(sbi, group_no, gdp);
spin_unlock(sb_bgl_lock(sbi, group_no));
- if (!EXT4_I(inode)->i_delalloc_reserved_flag && (*count != num)) {
- /*
- * we allocated less blocks than we
- * claimed. Add the difference back.
- */
- percpu_counter_add(&sbi->s_freeblocks_counter, *count - num);
- }
+ percpu_counter_sub(&sbi->s_freeblocks_counter, num);
+ /*
+ * Now reduce the dirty block count also. Should not go negative
+ */
+ if (!EXT4_I(inode)->i_delalloc_reserved_flag)
+ percpu_counter_sub(&sbi->s_dirtyblocks_counter, *count);
+ else
+ percpu_counter_sub(&sbi->s_dirtyblocks_counter, num);
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi, group_no);
spin_lock(sb_bgl_lock(sbi, flex_group));