ext4: fix free space estimate in ext4_nonda_switch()
Values stored in s_freeclusters_counter and s_dirtyclusters_counter
are both in cluster units. Remove the cluster to block conversion
applied to s_freeclusters_counter causing an inflated estimate of
free space because s_dirtyclusters_counter is not similarly
converted. Rename free_blocks and dirty_blocks to better reflect
the units these variables contain to avoid future confusion. This
fix corrects ENOSPC failures for xfstests 127 and 231 on bigalloc
file systems.
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index a29bfc2..f9b0b47 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2609,7 +2609,7 @@
static int ext4_nonda_switch(struct super_block *sb)
{
- s64 free_blocks, dirty_blocks;
+ s64 free_clusters, dirty_clusters;
struct ext4_sb_info *sbi = EXT4_SB(sb);
/*
@@ -2620,17 +2620,18 @@
* Delalloc need an accurate free block accounting. So switch
* to non delalloc when we are near to error range.
*/
- free_blocks = EXT4_C2B(sbi,
- percpu_counter_read_positive(&sbi->s_freeclusters_counter));
- dirty_blocks = percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
+ free_clusters =
+ percpu_counter_read_positive(&sbi->s_freeclusters_counter);
+ dirty_clusters =
+ percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
/*
* Start pushing delalloc when 1/2 of free blocks are dirty.
*/
- if (dirty_blocks && (free_blocks < 2 * dirty_blocks))
+ if (dirty_clusters && (free_clusters < 2 * dirty_clusters))
try_to_writeback_inodes_sb(sb, WB_REASON_FS_FREE_SPACE);
- if (2 * free_blocks < 3 * dirty_blocks ||
- free_blocks < (dirty_blocks + EXT4_FREECLUSTERS_WATERMARK)) {
+ if (2 * free_clusters < 3 * dirty_clusters ||
+ free_clusters < (dirty_clusters + EXT4_FREECLUSTERS_WATERMARK)) {
/*
* free block count is less than 150% of dirty blocks
* or free blocks is less than watermark