libdm: convert FIEMAP buffer allocation from stack to dm_zalloc

1 files changed, 21 insertions, 6 deletions

diff --git a/libdm/libdm-stats.c b/libdm/libdm-stats.c
index a033861ea..3cddae449 100644
--- a/libdm/libdm-stats.c
+++ b/libdm/libdm-stats.c
@@ -4195,9 +4195,9 @@ static int _stats_add_extent(struct dm_pool *mem, struct fiemap_extent *fm_ext,
 static struct _extent *_stats_get_extents_for_file(struct dm_pool *mem, int fd,
 						   uint64_t *count)
 {
-	uint64_t buf[STATS_FIE_BUF_LEN];
-	struct fiemap *fiemap = (struct fiemap *)buf;
-	struct fiemap_extent *fm_ext = &fiemap->fm_extents[0];
+	uint64_t *buf;
+	struct fiemap *fiemap = NULL;
+	struct fiemap_extent *fm_ext = NULL;
 	struct fiemap_extent fm_last = {0};
 	struct _extent *extents;
 	unsigned long long expected = 0;
@@ -4208,10 +4208,18 @@ static struct _extent *_stats_get_extents_for_file(struct dm_pool *mem, int fd,
 	int last = 0;
 	int rc;
 
-	memset(buf, 0, sizeof(buf));
+	buf = dm_zalloc(STATS_FIE_BUF_LEN);
+	if (!buf) {
+		log_error("Could not allocate memory for FIEMAP buffer.");
+		return NULL;
+	}
+
+	/* initialise pointers into the ioctl buffer. */
+	fiemap = (struct fiemap *) buf;
+	fm_ext = &fiemap->fm_extents[0];
 
 	/* space available per ioctl */
-	*count = (sizeof(buf) - sizeof(*fiemap))
+	*count = (STATS_FIE_BUF_LEN - sizeof(*fiemap))
 		  / sizeof(struct fiemap_extent);
 
 	/* grow temporary extent table in the pool */
@@ -4277,9 +4285,16 @@ static struct _extent *_stats_get_extents_for_file(struct dm_pool *mem, int fd,
 
 	/* return total number of extents */
 	*count = tot_extents;
-	return dm_pool_end_object(mem);
+	extents = dm_pool_end_object(mem);
+
+	/* free FIEMAP buffer. */
+	dm_free(buf);
+
+	return extents;
+
 bad:
 	dm_pool_abandon_object(mem);
+	dm_free(buf);
 	return NULL;
 }