Btrfs: cleanup unused latest_devid and latest_trans in fs_devices

The member variants - latest_devid and latest_trans - of fs_devices structure
are set, but no one use them to do anything. so remove them.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index e04424490f123ef589e7312329bacd8cd911399d..46cd29ad31566abe31bdbd3ea8c8e4d0c8d256b0 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -475,14 +475,13 @@ static noinline int device_list_add(const char *path,
                        return PTR_ERR(fs_devices);
 
                list_add(&fs_devices->list, &fs_uuids);
-               fs_devices->latest_devid = devid;
-               fs_devices->latest_trans = found_transid;
 
                device = NULL;
        } else {
                device = __find_device(&fs_devices->devices, devid,
                                       disk_super->dev_item.uuid);
        }
+
        if (!device) {
                if (fs_devices->opened)
                        return -EBUSY;
@@ -567,10 +566,6 @@ static noinline int device_list_add(const char *path,
        if (!fs_devices->opened)
                device->generation = found_transid;
 
-       if (found_transid > fs_devices->latest_trans) {
-               fs_devices->latest_devid = devid;
-               fs_devices->latest_trans = found_transid;
-       }
        *fs_devices_ret = fs_devices;
 
        return ret;
@@ -586,8 +581,6 @@ static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
        if (IS_ERR(fs_devices))
                return fs_devices;
 
-       fs_devices->latest_devid = orig->latest_devid;
-       fs_devices->latest_trans = orig->latest_trans;
        fs_devices->total_devices = orig->total_devices;
 
        /* We have held the volume lock, it is safe to get the devices. */
@@ -626,10 +619,7 @@ void btrfs_close_extra_devices(struct btrfs_fs_info *fs_info,
                               struct btrfs_fs_devices *fs_devices, int step)
 {
        struct btrfs_device *device, *next;
-
-       struct block_device *latest_bdev = NULL;
-       u64 latest_devid = 0;
-       u64 latest_transid = 0;
+       struct btrfs_device *latest_dev = NULL;
 
        mutex_lock(&uuid_mutex);
 again:
@@ -637,11 +627,9 @@ again:
        list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
                if (device->in_fs_metadata) {
                        if (!device->is_tgtdev_for_dev_replace &&
-                           (!latest_transid ||
-                            device->generation > latest_transid)) {
-                               latest_devid = device->devid;
-                               latest_transid = device->generation;
-                               latest_bdev = device->bdev;
+                           (!latest_dev ||
+                            device->generation > latest_dev->generation)) {
+                               latest_dev = device;
                        }
                        continue;
                }
@@ -683,9 +671,7 @@ again:
                goto again;
        }
 
-       fs_devices->latest_bdev = latest_bdev;
-       fs_devices->latest_devid = latest_devid;
-       fs_devices->latest_trans = latest_transid;
+       fs_devices->latest_bdev = latest_dev->bdev;
 
        mutex_unlock(&uuid_mutex);
 }
@@ -800,11 +786,9 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
        struct block_device *bdev;
        struct list_head *head = &fs_devices->devices;
        struct btrfs_device *device;
-       struct block_device *latest_bdev = NULL;
+       struct btrfs_device *latest_dev = NULL;
        struct buffer_head *bh;
        struct btrfs_super_block *disk_super;
-       u64 latest_devid = 0;
-       u64 latest_transid = 0;
        u64 devid;
        int seeding = 1;
        int ret = 0;
@@ -832,11 +816,9 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
                        goto error_brelse;
 
                device->generation = btrfs_super_generation(disk_super);
-               if (!latest_transid || device->generation > latest_transid) {
-                       latest_devid = devid;
-                       latest_transid = device->generation;
-                       latest_bdev = bdev;
-               }
+               if (!latest_dev ||
+                   device->generation > latest_dev->generation)
+                       latest_dev = device;
 
                if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
                        device->writeable = 0;
@@ -879,9 +861,7 @@ error_brelse:
        }
        fs_devices->seeding = seeding;
        fs_devices->opened = 1;
-       fs_devices->latest_bdev = latest_bdev;
-       fs_devices->latest_devid = latest_devid;
-       fs_devices->latest_trans = latest_transid;
+       fs_devices->latest_bdev = latest_dev->bdev;
        fs_devices->total_rw_bytes = 0;
 out:
        return ret;

diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 90d4fa80bd58c0ff4c14baf079bcabdb422cce31..e894ac696889b99acec84c5de40b1dedba6fa3e8 100644 (file)
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -119,9 +119,6 @@ struct btrfs_device {
 struct btrfs_fs_devices {
        u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */
 
-       /* the device with this id has the most recent copy of the super */
-       u64 latest_devid;
-       u64 latest_trans;
        u64 num_devices;
        u64 open_devices;
        u64 rw_devices;