diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 6a2cf75..ff4b1d5 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -1426,12 +1426,20 @@ static void rbio_update_error_bitmap(struct btrfs_raid_bio *rbio, struct bio *bi
 	u32 bio_size = 0;
 	struct bio_vec *bvec;
 	struct bvec_iter_all iter_all;
+	int i;
 
 	bio_for_each_segment_all(bvec, bio, iter_all)
 		bio_size += bvec->bv_len;
 
-	bitmap_set(rbio->error_bitmap, total_sector_nr,
-		   bio_size >> rbio->bioc->fs_info->sectorsize_bits);
+	/*
+	 * Since we can have multiple bios touching the error_bitmap, we cannot
+	 * call bitmap_set() without protection.
+	 *
+	 * Instead use set_bit() for each bit, as set_bit() itself is atomic.
+	 */
+	for (i = total_sector_nr; i < total_sector_nr +
+	     (bio_size >> rbio->bioc->fs_info->sectorsize_bits); i++)
+		set_bit(i, rbio->error_bitmap);
 }
 
 /* Verify the data sectors at read time. */
@@ -1886,7 +1894,7 @@ pstripe:
 		sector->uptodate = 1;
 	}
 	if (failb >= 0) {
-		ret = verify_one_sector(rbio, faila, sector_nr);
+		ret = verify_one_sector(rbio, failb, sector_nr);
 		if (ret < 0)
 			goto cleanup;
 
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index e65e6b6..d50182b 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -8073,10 +8073,10 @@ long btrfs_ioctl_send(struct inode *inode, struct btrfs_ioctl_send_args *arg)
 	/*
 	 * Check that we don't overflow at later allocations, we request
 	 * clone_sources_count + 1 items, and compare to unsigned long inside
-	 * access_ok.
+	 * access_ok. Also set an upper limit for allocation size so this can't
+	 * easily exhaust memory. Max number of clone sources is about 200K.
 	 */
-	if (arg->clone_sources_count >
-	    ULONG_MAX / sizeof(struct clone_root) - 1) {
+	if (arg->clone_sources_count > SZ_8M / sizeof(struct clone_root)) {
 		ret = -EINVAL;
 		goto out;
 	}
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index bcfef75..4cdadf3 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1600,7 +1600,7 @@ again:
 	if (ret < 0)
 		goto out;
 
-	while (1) {
+	while (search_start < search_end) {
 		l = path->nodes[0];
 		slot = path->slots[0];
 		if (slot >= btrfs_header_nritems(l)) {
@@ -1623,6 +1623,9 @@ again:
 		if (key.type != BTRFS_DEV_EXTENT_KEY)
 			goto next;
 
+		if (key.offset > search_end)
+			break;
+
 		if (key.offset > search_start) {
 			hole_size = key.offset - search_start;
 			dev_extent_hole_check(device, &search_start, &hole_size,
@@ -1683,6 +1686,7 @@ next:
 	else
 		ret = 0;
 
+	ASSERT(max_hole_start + max_hole_size <= search_end);
 out:
 	btrfs_free_path(path);
 	*start = max_hole_start;
diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
index 01a13de..da7bb91 100644
--- a/fs/btrfs/zlib.c
+++ b/fs/btrfs/zlib.c
@@ -63,7 +63,7 @@ struct list_head *zlib_alloc_workspace(unsigned int level)
 
 	workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
 			zlib_inflate_workspacesize());
-	workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
+	workspace->strm.workspace = kvzalloc(workspacesize, GFP_KERNEL);
 	workspace->level = level;
 	workspace->buf = NULL;
 	/*