From bbc4ec77e9f9c7ac71aee15c6adbd1674fe66c60 Mon Sep 17 00:00:00 2001 From: Ritesh Harjani Date: Sun, 10 May 2020 11:54:43 +0530 Subject: [PATCH] ext4: mballoc: add more mb_debug() msgs 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 Link: https://lore.kernel.org/r/5fc8e7788b924e211fcfa4a4c1d2f8503511661a.1589086800.git.riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o --- fs/ext4/mballoc.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index d1464d9..2e4697e 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -2108,7 +2108,7 @@ 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; @@ -2260,6 +2260,10 @@ repeat: 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; } @@ -3918,7 +3922,7 @@ 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)) { @@ -3926,7 +3930,7 @@ 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); @@ -3934,7 +3938,7 @@ 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) @@ -3979,6 +3983,8 @@ repeat: /* 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; } @@ -4003,6 +4009,9 @@ out: 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; } @@ -4538,6 +4547,7 @@ 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; } -- 2.7.4