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Commit 390eee95 authored by Kemeng Shi's avatar Kemeng Shi Committed by Greg Kroah-Hartman
Browse files

ext4: set goal start correctly in ext4_mb_normalize_request 



[ Upstream commit b07ffe6927c75d99af534d685282ea188d9f71a6 ]

We need to set ac_g_ex to notify the goal start used in
ext4_mb_find_by_goal. Set ac_g_ex instead of ac_f_ex in
ext4_mb_normalize_request.
Besides we should assure goal start is in range [first_data_block,
blocks_count) as ext4_mb_initialize_context does.

[ Added a check to make sure size is less than ar->pright; otherwise
  we could end up passing an underflowed value of ar->pright - size to
  ext4_get_group_no_and_offset(), which will trigger a BUG_ON later on.
  - TYT ]

Signed-off-by: default avatarKemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: default avatarRitesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20230303172120.3800725-2-shikemeng@huaweicloud.com


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent f92f44ea

fs/ext4/mballoc.c

+10 −6
Original line number Diff line number Diff line
@@ -3089,6 +3089,7 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac, 
				struct ext4_allocation_request *ar)

{

	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);

	struct ext4_super_block *es = sbi->s_es;

	int bsbits, max;

	ext4_lblk_t end;

	loff_t size, start_off;
@@ -3269,18 +3270,21 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac, 
	ac->ac_g_ex.fe_len = EXT4_NUM_B2C(sbi, size);



	/* define goal start in order to merge */

	if (ar->pright && (ar->lright == (start + size))) {

	if (ar->pright && (ar->lright == (start + size)) &&

	    ar->pright >= size &&

	    ar->pright - size >= le32_to_cpu(es->s_first_data_block)) {

		/* merge to the right */

		ext4_get_group_no_and_offset(ac->ac_sb, ar->pright - size,

						&ac->ac_f_ex.fe_group,

						&ac->ac_f_ex.fe_start);

						&ac->ac_g_ex.fe_group,

						&ac->ac_g_ex.fe_start);

		ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;

	}

	if (ar->pleft && (ar->lleft + 1 == start)) {

	if (ar->pleft && (ar->lleft + 1 == start) &&

	    ar->pleft + 1 < ext4_blocks_count(es)) {

		/* merge to the left */

		ext4_get_group_no_and_offset(ac->ac_sb, ar->pleft + 1,

						&ac->ac_f_ex.fe_group,

						&ac->ac_f_ex.fe_start);

						&ac->ac_g_ex.fe_group,

						&ac->ac_g_ex.fe_start);

		ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;

	}