1 files changed, 29 insertions, 8 deletions

diff --git a/fs/ext4/fsmap.c b/fs/ext4/fsmap.c
index 383c6edea6dd..22fc333244ef 100644
--- a/fs/ext4/fsmap.c
+++ b/fs/ext4/fsmap.c
@@ -74,7 +74,8 @@ static int ext4_getfsmap_dev_compare(const void *p1, const void *p2)
 static bool ext4_getfsmap_rec_before_low_key(struct ext4_getfsmap_info *info,
 					     struct ext4_fsmap *rec)
 {
-	return rec->fmr_physical < info->gfi_low.fmr_physical;
+	return rec->fmr_physical + rec->fmr_length <=
+	       info->gfi_low.fmr_physical;
 }
 
 /*
@@ -200,15 +201,18 @@ static int ext4_getfsmap_meta_helper(struct super_block *sb,
 			  ext4_group_first_block_no(sb, agno));
 	fs_end = fs_start + EXT4_C2B(sbi, len);
 
-	/* Return relevant extents from the meta_list */
+	/*
+	 * Return relevant extents from the meta_list. We emit all extents that
+	 * partially/fully overlap with the query range
+	 */
 	list_for_each_entry_safe(p, tmp, &info->gfi_meta_list, fmr_list) {
-		if (p->fmr_physical < info->gfi_next_fsblk) {
+		if (p->fmr_physical + p->fmr_length <= info->gfi_next_fsblk) {
 			list_del(&p->fmr_list);
 			kfree(p);
 			continue;
 		}
-		if (p->fmr_physical <= fs_start ||
-		    p->fmr_physical + p->fmr_length <= fs_end) {
+		if (p->fmr_physical <= fs_end &&
+		    p->fmr_physical + p->fmr_length > fs_start) {
 			/* Emit the retained free extent record if present */
 			if (info->gfi_lastfree.fmr_owner) {
 				error = ext4_getfsmap_helper(sb, info,
@@ -393,6 +397,14 @@ static unsigned int ext4_getfsmap_find_sb(struct super_block *sb,
 	/* Reserved GDT blocks */
 	if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) {
 		len = le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
+
+		/*
+		 * mkfs.ext4 can set s_reserved_gdt_blocks as 0 in some cases,
+		 * check for that.
+		 */
+		if (!len)
+			return 0;
+
 		error = ext4_getfsmap_fill(meta_list, fsb, len,
 					   EXT4_FMR_OWN_RESV_GDT);
 		if (error)
@@ -526,6 +538,7 @@ static int ext4_getfsmap_datadev(struct super_block *sb,
 	ext4_group_t end_ag;
 	ext4_grpblk_t first_cluster;
 	ext4_grpblk_t last_cluster;
+	struct ext4_fsmap irec;
 	int error = 0;
 
 	bofs = le32_to_cpu(sbi->s_es->s_first_data_block);
@@ -609,10 +622,18 @@ static int ext4_getfsmap_datadev(struct super_block *sb,
 			goto err;
 	}
 
-	/* Report any gaps at the end of the bg */
+	/*
+	 * The dummy record below will cause ext4_getfsmap_helper() to report
+	 * any allocated blocks at the end of the range.
+	 */
+	irec.fmr_device = 0;
+	irec.fmr_physical = end_fsb + 1;
+	irec.fmr_length = 0;
+	irec.fmr_owner = EXT4_FMR_OWN_FREE;
+	irec.fmr_flags = 0;
+
 	info->gfi_last = true;
-	error = ext4_getfsmap_datadev_helper(sb, end_ag, last_cluster + 1,
-					     0, info);
+	error = ext4_getfsmap_helper(sb, info, &irec);
 	if (error)
 		goto err;