Filipe David Borba Manana
2014-Apr-20 14:07 UTC
[PATCH 6/6] Btrfs: add send_stream_version attribute to sysfs
So that applications can find out what's the highest send stream
version supported/implemented by the running kernel:
$ cat /sys/fs/btrfs/send_stream_version
2
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
---
fs/btrfs/send.h | 1 +
fs/btrfs/sysfs.c | 36 ++++++++++++++++++++++++++++++++++++
2 files changed, 37 insertions(+)
diff --git a/fs/btrfs/send.h b/fs/btrfs/send.h
index 987936c..047fd6d 100644
--- a/fs/btrfs/send.h
+++ b/fs/btrfs/send.h
@@ -22,6 +22,7 @@
#define BTRFS_SEND_STREAM_MAGIC "btrfs-stream"
#define BTRFS_SEND_STREAM_VERSION_1 1
#define BTRFS_SEND_STREAM_VERSION_2 2
+#define BTRFS_SEND_STREAM_VERSION_LATEST BTRFS_SEND_STREAM_VERSION_2
#define BTRFS_SEND_BUF_SIZE (1024 * 64)
#define BTRFS_SEND_READ_SIZE (1024 * 48)
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 58a1dd1..2f8fff6 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -31,6 +31,7 @@
#include "transaction.h"
#include "sysfs.h"
#include "volumes.h"
+#include "send.h"
static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
@@ -662,6 +663,36 @@ static int btrfs_init_debugfs(void)
return 0;
}
+static ssize_t send_stream_version_show(struct kobject *kobj,
+ struct kobj_attribute *a,
+ char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "%d\n",
+ BTRFS_SEND_STREAM_VERSION_LATEST);
+}
+
+BTRFS_ATTR(send_stream_version, 0444, send_stream_version_show);
+
+static const struct attribute *btrfs_root_attrs[] = {
+ BTRFS_ATTR_PTR(send_stream_version),
+ NULL
+};
+
+static int add_root_attrs(struct kobject *kobj)
+{
+ int error = 0;
+ int i;
+
+ for (i = 0; btrfs_root_attrs[i]; i++) {
+ const struct attribute *a = btrfs_root_attrs[i];
+
+ error = sysfs_add_file_to_group(kobj->parent, a, kobj->name);
+ if (error)
+ break;
+ }
+ return error;
+}
+
int btrfs_init_sysfs(void)
{
int ret;
@@ -678,8 +709,13 @@ int btrfs_init_sysfs(void)
ret = sysfs_create_group(&btrfs_kset->kobj,
&btrfs_feature_attr_group);
if (ret)
goto out2;
+ ret = add_root_attrs(&btrfs_kset->kobj);
+ if (ret)
+ goto out3;
return 0;
+out3:
+ sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
out2:
debugfs_remove_recursive(btrfs_debugfs_root_dentry);
out1:
--
1.9.1
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