[PATCH v2] btrfs-progs: fix memory leaks in error path

[Byongho Lee <bhlee.kernel@gmail.com>]

This patch includes below fixes in error path:
1. fix memory leaks if realloc() fails
2. add missing call free_history() before return error in scrub_read_file()

Signed-off-by: Byongho Lee <bhlee.kernel@gmail.com>
---
changelog:
v2:
  Add one more fix for memory leak when realloc() fails by Zhao Lei's comment.
---
 btrfs-list.c |  8 ++++++++
 cmds-scrub.c | 18 ++++++++++++++----
 cmds-send.c  |  7 ++++++-
 qgroup.c     |  8 ++++++++
 4 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/btrfs-list.c b/btrfs-list.c
index 875a89dc4ef0..d54de61aec01 100644
--- a/btrfs-list.c
+++ b/btrfs-list.c
@@ -254,11 +254,15 @@ static int btrfs_list_setup_comparer(struct btrfs_list_comparer_set **comp_set,
 	BUG_ON(set->ncomps > set->total);
 
 	if (set->ncomps == set->total) {
+		void *tmp;
+
 		size = set->total + BTRFS_LIST_NCOMPS_INCREASE;
 		size = sizeof(*set) + size * sizeof(struct btrfs_list_comparer);
+		tmp = set;
 		set = realloc(set, size);
 		if (!set) {
 			fprintf(stderr, "memory allocation failed\n");
+			free(tmp);
 			exit(1);
 		}
 
@@ -1232,11 +1236,15 @@ int btrfs_list_setup_filter(struct btrfs_list_filter_set **filter_set,
 	BUG_ON(set->nfilters > set->total);
 
 	if (set->nfilters == set->total) {
+		void *tmp;
+
 		size = set->total + BTRFS_LIST_NFILTERS_INCREASE;
 		size = sizeof(*set) + size * sizeof(struct btrfs_list_filter);
+		tmp = set;
 		set = realloc(set, size);
 		if (!set) {
 			fprintf(stderr, "memory allocation failed\n");
+			free(tmp);
 			exit(1);
 		}
 
diff --git a/cmds-scrub.c b/cmds-scrub.c
index 5a85dc473c94..91cf67841849 100644
--- a/cmds-scrub.c
+++ b/cmds-scrub.c
@@ -502,12 +502,16 @@ again:
 		}
 		return p;
 	}
-	if (avail == -1)
+	if (avail == -1) {
+		free_history(p);
 		return ERR_PTR(-errno);
+	}
 	avail += old_avail;
 
 	i = 0;
 	while (i < avail) {
+		void *tmp;
+
 		switch (state) {
 		case 0: /* start of file */
 			ret = scrub_kvread(&i,
@@ -534,11 +538,17 @@ again:
 				continue;
 			}
 			++curr;
+			tmp = p;
 			p = realloc(p, (curr + 2) * sizeof(*p));
-			if (p)
-				p[curr] = malloc(sizeof(**p));
-			if (!p || !p[curr])
+			if (!p) {
+				free_history(tmp);
 				return ERR_PTR(-errno);
+			}
+			p[curr] = malloc(sizeof(**p));
+			if (!p[curr]) {
+				free_history(p);
+				return ERR_PTR(-errno);
+			}
 			memset(p[curr], 0, sizeof(**p));
 			p[curr + 1] = NULL;
 			++state;
diff --git a/cmds-send.c b/cmds-send.c
index a0b7f95fa23a..95fd4aaacbf8 100644
--- a/cmds-send.c
+++ b/cmds-send.c
@@ -174,11 +174,16 @@ out:
 
 static int add_clone_source(struct btrfs_send *s, u64 root_id)
 {
+	void *tmp;
+
+	tmp = s->clone_sources;
 	s->clone_sources = realloc(s->clone_sources,
 		sizeof(*s->clone_sources) * (s->clone_sources_count + 1));
 
-	if (!s->clone_sources)
+	if (!s->clone_sources) {
+		free(tmp);
 		return -ENOMEM;
+	}
 	s->clone_sources[s->clone_sources_count++] = root_id;
 
 	return 0;
diff --git a/qgroup.c b/qgroup.c
index dc04b033b145..327abd645f16 100644
--- a/qgroup.c
+++ b/qgroup.c
@@ -465,12 +465,16 @@ int btrfs_qgroup_setup_comparer(struct btrfs_qgroup_comparer_set  **comp_set,
 	BUG_ON(set->ncomps > set->total);
 
 	if (set->ncomps == set->total) {
+		void *tmp;
+
 		size = set->total + BTRFS_QGROUP_NCOMPS_INCREASE;
 		size = sizeof(*set) +
 		       size * sizeof(struct btrfs_qgroup_comparer);
+		tmp = set;
 		set = realloc(set, size);
 		if (!set) {
 			fprintf(stderr, "memory allocation failed\n");
+			free(tmp);
 			exit(1);
 		}
 
@@ -836,12 +840,16 @@ int btrfs_qgroup_setup_filter(struct btrfs_qgroup_filter_set **filter_set,
 	BUG_ON(set->nfilters > set->total);
 
 	if (set->nfilters == set->total) {
+		void *tmp;
+
 		size = set->total + BTRFS_QGROUP_NFILTERS_INCREASE;
 		size = sizeof(*set) + size * sizeof(struct btrfs_qgroup_filter);
 
+		tmp = set;
 		set = realloc(set, size);
 		if (!set) {
 			fprintf(stderr, "memory allocation failed\n");
+			free(tmp);
 			exit(1);
 		}
 		memset(&set->filters[set->total], 0,
-- 
2.5.0