ext4: move setting of trimmed bit into ext4_try_to_trim_range()

Currently we set the group's trimmed bit in ext4_trim_all_free() based
on return value of ext4_try_to_trim_range(). However when we will want
to abort trimming because of suspend attempt, we want to return success
from ext4_try_to_trim_range() but not set the trimmed bit. Instead
implementing awkward propagation of this information, just move setting
of trimmed bit into ext4_try_to_trim_range() when the whole group is
trimmed.

Cc: stable@kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230913150504.9054-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Author: jankara

fs/ext4/mballoc.c

@@ -6906,16 +6906,29 @@ __acquires(bitlock)
 	return ret;
 }
 
+static ext4_grpblk_t ext4_last_grp_cluster(struct super_block *sb,
+					   ext4_group_t grp)
+{
+	if (grp < ext4_get_groups_count(sb))
+		return EXT4_CLUSTERS_PER_GROUP(sb) - 1;
+	return (ext4_blocks_count(EXT4_SB(sb)->s_es) -
+		ext4_group_first_block_no(sb, grp) - 1) >>
+					EXT4_CLUSTER_BITS(sb);
+}
+
 static int ext4_try_to_trim_range(struct super_block *sb,
 		struct ext4_buddy *e4b, ext4_grpblk_t start,
 		ext4_grpblk_t max, ext4_grpblk_t minblocks)
 __acquires(ext4_group_lock_ptr(sb, e4b->bd_group))
 __releases(ext4_group_lock_ptr(sb, e4b->bd_group))
 {
 	ext4_grpblk_t next, count, free_count;
+	bool set_trimmed = false;
 	void *bitmap;
 
 	bitmap = e4b->bd_bitmap;
+	if (start == 0 && max >= ext4_last_grp_cluster(sb, e4b->bd_group))
+		set_trimmed = true;
 	start = max(e4b->bd_info->bb_first_free, start);
 	count = 0;
 	free_count = 0;
@@ -6930,16 +6943,14 @@ __releases(ext4_group_lock_ptr(sb, e4b->bd_group))
 			int ret = ext4_trim_extent(sb, start, next - start, e4b);
 
 			if (ret && ret != -EOPNOTSUPP)
-				break;
+				return count;
 			count += next - start;
 		}
 		free_count += next - start;
 		start = next + 1;
 
-		if (fatal_signal_pending(current)) {
-			count = -ERESTARTSYS;
-			break;
-		}
+		if (fatal_signal_pending(current))
+			return -ERESTARTSYS;
 
 		if (need_resched()) {
 			ext4_unlock_group(sb, e4b->bd_group);
@@ -6951,6 +6962,9 @@ __releases(ext4_group_lock_ptr(sb, e4b->bd_group))
 			break;
 	}
 
+	if (set_trimmed)
+		EXT4_MB_GRP_SET_TRIMMED(e4b->bd_info);
+
 	return count;
 }
 
@@ -6961,7 +6975,6 @@ __releases(ext4_group_lock_ptr(sb, e4b->bd_group))
  * @start:		first group block to examine
  * @max:		last group block to examine
  * @minblocks:		minimum extent block count
- * @set_trimmed:	set the trimmed flag if at least one block is trimmed
  *
  * ext4_trim_all_free walks through group's block bitmap searching for free
  * extents. When the free extent is found, mark it as used in group buddy
@@ -6971,7 +6984,7 @@ __releases(ext4_group_lock_ptr(sb, e4b->bd_group))
 static ext4_grpblk_t
 ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
 		   ext4_grpblk_t start, ext4_grpblk_t max,
-		   ext4_grpblk_t minblocks, bool set_trimmed)
+		   ext4_grpblk_t minblocks)
 {
 	struct ext4_buddy e4b;
 	int ret;
@@ -6988,13 +7001,10 @@ ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
 	ext4_lock_group(sb, group);
 
 	if (!EXT4_MB_GRP_WAS_TRIMMED(e4b.bd_info) ||
-	    minblocks < EXT4_SB(sb)->s_last_trim_minblks) {
+	    minblocks < EXT4_SB(sb)->s_last_trim_minblks)
 		ret = ext4_try_to_trim_range(sb, &e4b, start, max, minblocks);
-		if (ret >= 0 && set_trimmed)
-			EXT4_MB_GRP_SET_TRIMMED(e4b.bd_info);
-	} else {
+	else
 		ret = 0;
-	}
 
 	ext4_unlock_group(sb, group);
 	ext4_mb_unload_buddy(&e4b);
@@ -7027,7 +7037,6 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
 	ext4_fsblk_t first_data_blk =
 			le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
 	ext4_fsblk_t max_blks = ext4_blocks_count(EXT4_SB(sb)->s_es);
-	bool whole_group, eof = false;
 	int ret = 0;
 
 	start = range->start >> sb->s_blocksize_bits;
@@ -7046,10 +7055,8 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
 		if (minlen > EXT4_CLUSTERS_PER_GROUP(sb))
 			goto out;
 	}
-	if (end >= max_blks - 1) {
+	if (end >= max_blks - 1)
 		end = max_blks - 1;
-		eof = true;
-	}
 	if (end <= first_data_blk)
 		goto out;
 	if (start < first_data_blk)
@@ -7063,7 +7070,6 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
 
 	/* end now represents the last cluster to discard in this group */
 	end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
-	whole_group = true;
 
 	for (group = first_group; group <= last_group; group++) {
 		grp = ext4_get_group_info(sb, group);
@@ -7082,13 +7088,11 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
 		 * change it for the last group, note that last_cluster is
 		 * already computed earlier by ext4_get_group_no_and_offset()
 		 */
-		if (group == last_group) {
+		if (group == last_group)
 			end = last_cluster;
-			whole_group = eof ? true : end == EXT4_CLUSTERS_PER_GROUP(sb) - 1;
-		}
 		if (grp->bb_free >= minlen) {
 			cnt = ext4_trim_all_free(sb, group, first_cluster,
-						 end, minlen, whole_group);
+						 end, minlen);
 			if (cnt < 0) {
 				ret = cnt;
 				break;