[PATCH 4/4] btrfs: show used checksum driver per filesystem in sysfs

[Johannes Thumshirn]

Show the used driver for the checksum algorithm for the filesystem in
sysfs.

Signed-off-by: Johannes Thumshirn <jthumsh...@suse.de>
---
 fs/btrfs/sysfs.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index aeebbdfe1a98..11a3cf7f563e 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -9,6 +9,7 @@
 #include <linux/spinlock.h>
 #include <linux/completion.h>
 #include <linux/bug.h>
+#include <crypto/hash.h>
 
 #include "ctree.h"
 #include "disk-io.h"
@@ -637,6 +638,19 @@ static ssize_t btrfs_metadata_uuid_show(struct kobject 
*kobj,
 
 BTRFS_ATTR(, metadata_uuid, btrfs_metadata_uuid_show);
 
+static ssize_t btrfs_checksum_show(struct kobject *kobj,
+                                  struct kobj_attribute *a, char *buf)
+{
+       struct btrfs_fs_info *fs_info = to_fs_info(kobj);
+       u16 csum_type = btrfs_super_csum_type(fs_info->super_copy);
+
+       return snprintf(buf, PAGE_SIZE, "%s (%s)\n",
+                       btrfs_super_csum_name(csum_type),
+                       crypto_shash_driver_name(fs_info->csum_shash));
+}
+
+BTRFS_ATTR(, checksum, btrfs_checksum_show);
+
 static const struct attribute *btrfs_attrs[] = {
        BTRFS_ATTR_PTR(, label),
        BTRFS_ATTR_PTR(, nodesize),
@@ -644,6 +658,7 @@ static const struct attribute *btrfs_attrs[] = {
        BTRFS_ATTR_PTR(, clone_alignment),
        BTRFS_ATTR_PTR(, quota_override),
        BTRFS_ATTR_PTR(, metadata_uuid),
+       BTRFS_ATTR_PTR(, checksum),
        NULL,
 };
 
-- 
2.16.4