@@ -2137,7 +2137,7 @@ static noinline_for_stack int
ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
{
ext4_group_t ngroups, group, i;
- int cr;
+ int cr = -1;
int err = 0, first_err = 0;
struct ext4_sb_info *sbi;
struct super_block *sb;
@@ -2289,6 +2289,10 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
out:
if (!err && ac->ac_status != AC_STATUS_FOUND && first_err)
err = first_err;
+
+ mb_debug(1, "Best len %d, origin len %d, ac_status %u, ac_flags 0x%x, cr %d ret %d\n",
+ ac->ac_b_ex.fe_len, ac->ac_o_ex.fe_len, ac->ac_status,
+ ac->ac_flags, cr, err);
return err;
}
@@ -3949,7 +3953,7 @@ ext4_mb_discard_group_preallocations(struct super_block *sb,
mb_debug(1, "discard preallocation for group %u\n", group);
if (list_empty(&grp->bb_prealloc_list))
- return 0;
+ goto out_dbg;
bitmap_bh = ext4_read_block_bitmap(sb, group);
if (IS_ERR(bitmap_bh)) {
@@ -3957,7 +3961,7 @@ ext4_mb_discard_group_preallocations(struct super_block *sb,
ext4_error_err(sb, -err,
"Error %d reading block bitmap for %u",
err, group);
- return 0;
+ goto out_dbg;
}
err = ext4_mb_load_buddy(sb, group, &e4b);
@@ -3965,7 +3969,7 @@ ext4_mb_discard_group_preallocations(struct super_block *sb,
ext4_warning(sb, "Error %d loading buddy information for %u",
err, group);
put_bh(bitmap_bh);
- return 0;
+ goto out_dbg;
}
if (needed == 0)
@@ -4011,6 +4015,8 @@ ext4_mb_discard_group_preallocations(struct super_block *sb,
/* found anything to free? */
if (list_empty(&list)) {
BUG_ON(free != 0);
+ mb_debug(1, "Someone else may have freed PA for this group %u\n",
+ group);
goto out;
}
@@ -4035,6 +4041,9 @@ ext4_mb_discard_group_preallocations(struct super_block *sb,
ext4_unlock_group(sb, group);
ext4_mb_unload_buddy(&e4b);
put_bh(bitmap_bh);
+out_dbg:
+ mb_debug(1, "discarded (%d) blocks preallocated for group %u bb_free (%d)\n",
+ free, group, grp->bb_free);
return free;
}
@@ -4602,6 +4611,7 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
ar->len = ar->len >> 1;
}
if (!ar->len) {
+ ext4_mb_show_pa(sb);
*errp = -ENOSPC;
return 0;
}
This patch adds some more debugging mb_debug() msgs to help improve mballoc code debugging. Other than adding more mb_debug() msgs at few more places, there should be no other functionality change in this patch. Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> --- fs/ext4/mballoc.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)