[PATCH v3 2/4] btrfs: redeclare btrfs_stale_devices arg1 to dev_t

[Anand Jain <anand.jain@oracle.com>]

After the commit cb57afa39796 ("btrfs: harden identification of the stale
device"), we don't have to match the device path anymore. Instead, we
match the dev_t. So pass in the dev_t instead of the device-path, in the call
chain btrfs_forget_devices()->btrfs_free_stale_devices().

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
v3: -

 fs/btrfs/super.c   |  8 +++++++-
 fs/btrfs/volumes.c | 45 +++++++++++++++++++++++----------------------
 fs/btrfs/volumes.h |  2 +-
 3 files changed, 31 insertions(+), 24 deletions(-)

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 1ff03fb6c64a..bdf54b2673fe 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -2386,6 +2386,7 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
 {
 	struct btrfs_ioctl_vol_args *vol;
 	struct btrfs_device *device = NULL;
+	dev_t devt = 0;
 	int ret = -ENOTTY;
 
 	if (!capable(CAP_SYS_ADMIN))
@@ -2405,7 +2406,12 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
 		mutex_unlock(&uuid_mutex);
 		break;
 	case BTRFS_IOC_FORGET_DEV:
-		ret = btrfs_forget_devices(vol->name);
+		if (strlen(vol->name)) {
+			ret = lookup_bdev(vol->name, &devt);
+			if (ret)
+				break;
+		}
+		ret = btrfs_forget_devices(devt);
 		break;
 	case BTRFS_IOC_DEVICES_READY:
 		mutex_lock(&uuid_mutex);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index ad9e08c3199c..cb43ee5925ad 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -543,11 +543,10 @@ btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
  *	1	If it is not the same device.
  *	-errno	For error.
  */
-static int device_matched(struct btrfs_device *device, const char *path)
+static int device_matched(struct btrfs_device *device, dev_t dev_new)
 {
 	char *device_name;
 	dev_t dev_old;
-	dev_t dev_new;
 	int ret;
 
 	device_name = kzalloc(BTRFS_PATH_NAME_MAX, GFP_KERNEL);
@@ -567,10 +566,6 @@ static int device_matched(struct btrfs_device *device, const char *path)
 	if (ret)
 		return ret;
 
-	ret = lookup_bdev(path, &dev_new);
-	if (ret)
-		return ret;
-
 	if (dev_old == dev_new)
 		return 0;
 
@@ -580,16 +575,16 @@ static int device_matched(struct btrfs_device *device, const char *path)
 /*
  *  Search and remove all stale (devices which are not mounted) devices.
  *  When both inputs are NULL, it will search and release all stale devices.
- *  path:	Optional. When provided will it release all unmounted devices
- *		matching this path only.
+ *  devt:	Optional. When provided will it release all unmounted devices
+ *		matching this devt only.
  *  skip_dev:	Optional. Will skip this device when searching for the stale
  *		devices.
- *  Return:	0 for success or if @path is NULL.
- * 		-EBUSY if @path is a mounted device.
- * 		-ENOENT if @path does not match any device in the list.
+ *  Return:	0 for success or if @devt is 0.
+ *		-EBUSY if @devt is a mounted device.
+ *		-ENOENT if @devt does not match any device in the list.
  */
-static int btrfs_free_stale_devices(const char *path,
-				     struct btrfs_device *skip_device)
+static int btrfs_free_stale_devices(dev_t devt,
+				    struct btrfs_device *skip_device)
 {
 	struct btrfs_fs_devices *fs_devices, *tmp_fs_devices;
 	struct btrfs_device *device, *tmp_device;
@@ -597,7 +592,7 @@ static int btrfs_free_stale_devices(const char *path,
 
 	lockdep_assert_held(&uuid_mutex);
 
-	if (path)
+	if (devt)
 		ret = -ENOENT;
 
 	list_for_each_entry_safe(fs_devices, tmp_fs_devices, &fs_uuids, fs_list) {
@@ -607,13 +602,13 @@ static int btrfs_free_stale_devices(const char *path,
 					 &fs_devices->devices, dev_list) {
 			if (skip_device && skip_device == device)
 				continue;
-			if (path && !device->name)
+			if (devt && !device->name)
 				continue;
-			if (path && device_matched(device, path) != 0)
+			if (devt && device_matched(device, devt) != 0)
 				continue;
 			if (fs_devices->opened) {
 				/* for an already deleted device return 0 */
-				if (path && ret != 0)
+				if (devt && ret != 0)
 					ret = -EBUSY;
 				break;
 			}
@@ -1372,12 +1367,12 @@ static struct btrfs_super_block *btrfs_read_disk_super(struct block_device *bdev
 	return disk_super;
 }
 
-int btrfs_forget_devices(const char *path)
+int btrfs_forget_devices(dev_t devt)
 {
 	int ret;
 
 	mutex_lock(&uuid_mutex);
-	ret = btrfs_free_stale_devices(strlen(path) ? path : NULL, NULL);
+	ret = btrfs_free_stale_devices(devt, NULL);
 	mutex_unlock(&uuid_mutex);
 
 	return ret;
@@ -1427,8 +1422,12 @@ struct btrfs_device *btrfs_scan_one_device(const char *path, fmode_t flags,
 
 	device = device_list_add(path, disk_super, &new_device_added);
 	if (!IS_ERR(device)) {
-		if (new_device_added)
-			btrfs_free_stale_devices(path, device);
+		if (new_device_added) {
+			dev_t devt;
+
+			if (!lookup_bdev(path, &devt))
+				btrfs_free_stale_devices(devt, device);
+		}
 	}
 
 	btrfs_release_disk_super(disk_super);
@@ -2659,6 +2658,7 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
 	int ret = 0;
 	bool seeding_dev = false;
 	bool locked = false;
+	dev_t devt;
 
 	if (sb_rdonly(sb) && !fs_devices->seeding)
 		return -EROFS;
@@ -2853,7 +2853,8 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
 	 * We can ignore the return value as it typically returns -EINVAL and
 	 * only succeeds if the device was an alien.
 	 */
-	btrfs_forget_devices(device_path);
+	if (!lookup_bdev(device_path, &devt))
+		btrfs_forget_devices(devt);
 
 	/* Update ctime/mtime for blkid or udev */
 	update_dev_time(device_path);
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 98bbb293a3f9..76215de8ce34 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -529,7 +529,7 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 		       fmode_t flags, void *holder);
 struct btrfs_device *btrfs_scan_one_device(const char *path,
 					   fmode_t flags, void *holder);
-int btrfs_forget_devices(const char *path);
+int btrfs_forget_devices(dev_t devt);
 void btrfs_close_devices(struct btrfs_fs_devices *fs_devices);
 void btrfs_free_extra_devids(struct btrfs_fs_devices *fs_devices);
 void btrfs_assign_next_active_device(struct btrfs_device *device,
-- 
2.33.1