diff mbox series

[8/8] ext4: try all groups in ext4_mb_new_blocks_simple

Message ID 20230321161220.418652-9-shikemeng@huaweicloud.com
State Superseded
Headers show
Series Some fixes and cleanup to mballoc | expand

Commit Message

Kemeng Shi March 21, 2023, 4:12 p.m. UTC 
ext4_mb_new_blocks_simple ignores the group before goal, so it will fail
if free blocks reside in group before goal. Try all groups to avoid
unexpected failure.
Search finishes either if any free block is found or if no available
blocks are found. Simpliy check "i >= max" to distinguish the above
cases.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Suggested-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/mballoc.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

Comments

Ojaswin Mujoo April 7, 2023, 11:10 a.m. UTC | #1 
On Wed, Mar 22, 2023 at 12:12:20AM +0800, Kemeng Shi wrote:
> ext4_mb_new_blocks_simple ignores the group before goal, so it will fail
> if free blocks reside in group before goal. Try all groups to avoid
> unexpected failure.
> Search finishes either if any free block is found or if no available
> blocks are found. Simpliy check "i >= max" to distinguish the above
> cases.
> 
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
> Suggested-by: Theodore Ts'o <tytso@mit.edu>
> ---
>  fs/ext4/mballoc.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)

Feel free to add:

Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>

Regards,
ojaswin
diff mbox series

Patch

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 5b837918c624..ee564e700278 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -5796,7 +5796,7 @@  static ext4_fsblk_t ext4_mb_new_blocks_simple(handle_t *handle,
 	struct buffer_head *bitmap_bh;
 	struct super_block *sb = ar->inode->i_sb;
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
-	ext4_group_t group;
+	ext4_group_t group, nr;
 	ext4_grpblk_t blkoff;
 	ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
 	ext4_grpblk_t i = 0;
@@ -5810,7 +5810,7 @@  static ext4_fsblk_t ext4_mb_new_blocks_simple(handle_t *handle,
 
 	ar->len = 0;
 	ext4_get_group_no_and_offset(sb, goal, &group, &blkoff);
-	for (; group < ext4_get_groups_count(sb); group++) {
+	for (nr = ext4_get_groups_count(sb); nr > 0; nr--) {
 		bitmap_bh = ext4_read_block_bitmap(sb, group);
 		if (IS_ERR(bitmap_bh)) {
 			*errp = PTR_ERR(bitmap_bh);
@@ -5834,10 +5834,13 @@  static ext4_fsblk_t ext4_mb_new_blocks_simple(handle_t *handle,
 		if (i < max)
 			break;
 
+		if (++group >= ext4_get_groups_count(sb))
+			group = 0;
+
 		blkoff = 0;
 	}
 
-	if (group >= ext4_get_groups_count(sb) || i >= max) {
+	if (i >= max) {
 		*errp = -ENOSPC;
 		return 0;
 	}