[PATCH 2/3] btrfs: export currently executing exclusive operation via sysfs

[Goldwyn Rodrigues <rgoldwyn@suse.de>]

From: Goldwyn Rodrigues <rgoldwyn@suse.com>

/sys/fs/<fsid>/exclusive_operation contains the currently executing
exclusive operation. Add a sysfs_notify() when operation end, so
userspace can be notified of exclusive operation is finished.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
---
 fs/btrfs/ioctl.c |  2 ++
 fs/btrfs/sysfs.c | 25 +++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 2f45b88d7eed..a00d6d5c42c1 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -373,6 +373,8 @@ bool btrfs_exclop_start(struct btrfs_fs_info *fs_info, int type)
 void btrfs_exclop_finish(struct btrfs_fs_info *fs_info)
 {
 	atomic_set(&fs_info->exclusive_operation, BTRFS_EXCLOP_NONE);
+	sysfs_notify(&fs_info->fs_devices->fsid_kobj, NULL,
+			"exclusive_operation");
 }
 
 /*
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index a39bff64ff24..71950c121588 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -808,6 +808,30 @@ static ssize_t btrfs_checksum_show(struct kobject *kobj,
 
 BTRFS_ATTR(, checksum, btrfs_checksum_show);
 
+static ssize_t btrfs_exclusive_operation_show(struct kobject *kobj,
+		struct kobj_attribute *a, char *buf)
+{
+	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
+	switch (atomic_read(&fs_info->exclusive_operation)) {
+		case  BTRFS_EXCLOP_NONE:
+			return scnprintf(buf, PAGE_SIZE, "none\n");
+		case BTRFS_EXCLOP_BALANCE:
+			return scnprintf(buf, PAGE_SIZE, "balance\n");
+		case BTRFS_EXCLOP_DEV_ADD:
+			return scnprintf(buf, PAGE_SIZE, "device add\n");
+		case BTRFS_EXCLOP_DEV_REPLACE:
+			return scnprintf(buf, PAGE_SIZE, "device replace\n");
+		case BTRFS_EXCLOP_DEV_REMOVE:
+			return scnprintf(buf, PAGE_SIZE, "device remove\n");
+		case BTRFS_EXCLOP_SWAP_ACTIVATE:
+			return scnprintf(buf, PAGE_SIZE, "swap activate\n");
+		case BTRFS_EXCLOP_RESIZE:
+			return scnprintf(buf, PAGE_SIZE, "resize\n");
+	}
+	return 0;
+}
+BTRFS_ATTR(, exclusive_operation, btrfs_exclusive_operation_show);
+
 static const struct attribute *btrfs_attrs[] = {
 	BTRFS_ATTR_PTR(, label),
 	BTRFS_ATTR_PTR(, nodesize),
@@ -816,6 +840,7 @@ static const struct attribute *btrfs_attrs[] = {
 	BTRFS_ATTR_PTR(, quota_override),
 	BTRFS_ATTR_PTR(, metadata_uuid),
 	BTRFS_ATTR_PTR(, checksum),
+	BTRFS_ATTR_PTR(, exclusive_operation),
 	NULL,
 };
 
-- 
2.26.2