btrfs: return device pointer from btrfs_scan_one_device

Return device pointer (with the IS_ERR semantics) from
btrfs_scan_one_device so we don't have to return in through pointer.

And since btrfs_fs_devices can be obtained from btrfs_device, return that.

Signed-off-by: Gu Jinxiang <gujx@cn.fujitsu.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ fixed conflics after recent changes to btrfs_scan_one_device ]
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 909ea25..5384afa 100644 (file)
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -888,7 +888,7 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags,
 {
        substring_t args[MAX_OPT_ARGS];
        char *device_name, *opts, *orig, *p;
-       struct btrfs_fs_devices *fs_devices = NULL;
+       struct btrfs_device *device = NULL;
        int error = 0;
 
        lockdep_assert_held(&uuid_mutex);
@@ -918,11 +918,13 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags,
                                error = -ENOMEM;
                                goto out;
                        }
-                       error = btrfs_scan_one_device(device_name,
-                                       flags, holder, &fs_devices);
+                       device = btrfs_scan_one_device(device_name, flags,
+                                       holder);
                        kfree(device_name);
-                       if (error)
+                       if (IS_ERR(device)) {
+                               error = PTR_ERR(device);
                                goto out;
+                       }
                }
        }
 
@@ -1518,6 +1520,7 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
 {
        struct block_device *bdev = NULL;
        struct super_block *s;
+       struct btrfs_device *device = NULL;
        struct btrfs_fs_devices *fs_devices = NULL;
        struct btrfs_fs_info *fs_info = NULL;
        struct security_mnt_opts new_sec_opts;
@@ -1561,12 +1564,14 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
                goto error_fs_info;
        }
 
-       error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
-       if (error) {
+       device = btrfs_scan_one_device(device_name, mode, fs_type);
+       if (IS_ERR(device)) {
                mutex_unlock(&uuid_mutex);
+               error = PTR_ERR(device);
                goto error_fs_info;
        }
 
+       fs_devices = device->fs_devices;
        fs_info->fs_devices = fs_devices;
 
        error = btrfs_open_devices(fs_devices, mode, fs_type);
@@ -2227,7 +2232,7 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
                                unsigned long arg)
 {
        struct btrfs_ioctl_vol_args *vol;
-       struct btrfs_fs_devices *fs_devices;
+       struct btrfs_device *device = NULL;
        int ret = -ENOTTY;
 
        if (!capable(CAP_SYS_ADMIN))
@@ -2240,19 +2245,22 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
        switch (cmd) {
        case BTRFS_IOC_SCAN_DEV:
                mutex_lock(&uuid_mutex);
-               ret = btrfs_scan_one_device(vol->name, FMODE_READ,
-                                           &btrfs_root_fs_type, &fs_devices);
+               device = btrfs_scan_one_device(vol->name, FMODE_READ,
+                                              &btrfs_root_fs_type);
+               ret = PTR_ERR_OR_ZERO(device);
                mutex_unlock(&uuid_mutex);
                break;
        case BTRFS_IOC_DEVICES_READY:
                mutex_lock(&uuid_mutex);
-               ret = btrfs_scan_one_device(vol->name, FMODE_READ,
-                                           &btrfs_root_fs_type, &fs_devices);
-               if (ret) {
+               device = btrfs_scan_one_device(vol->name, FMODE_READ,
+                                              &btrfs_root_fs_type);
+               if (IS_ERR(device)) {
                        mutex_unlock(&uuid_mutex);
+                       ret = PTR_ERR(device);
                        break;
                }
-               ret = !(fs_devices->num_devices == fs_devices->total_devices);
+               ret = !(device->fs_devices->num_devices ==
+                       device->fs_devices->total_devices);
                mutex_unlock(&uuid_mutex);
                break;
        case BTRFS_IOC_GET_SUPPORTED_FEATURES:

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 459cc2a..fd9d4e0 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1213,15 +1213,14 @@ static int btrfs_read_disk_super(struct block_device *bdev, u64 bytenr,
  * and we are not allowed to call set_blocksize during the scan. The superblock
  * is read via pagecache
  */
-int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
-                         struct btrfs_fs_devices **fs_devices_ret)
+struct btrfs_device *btrfs_scan_one_device(const char *path, fmode_t flags,
+                                          void *holder)
 {
        struct btrfs_super_block *disk_super;
        bool new_device_added = false;
-       struct btrfs_device *device;
+       struct btrfs_device *device = NULL;
        struct block_device *bdev;
        struct page *page;
-       int ret = 0;
        u64 bytenr;
 
        lockdep_assert_held(&uuid_mutex);
@@ -1237,18 +1236,15 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 
        bdev = blkdev_get_by_path(path, flags, holder);
        if (IS_ERR(bdev))
-               return PTR_ERR(bdev);
+               return ERR_CAST(bdev);
 
        if (btrfs_read_disk_super(bdev, bytenr, &page, &disk_super)) {
-               ret = -EINVAL;
+               device = ERR_PTR(-EINVAL);
                goto error_bdev_put;
        }
 
        device = device_list_add(path, disk_super, &new_device_added);
-       if (IS_ERR(device)) {
-               ret = PTR_ERR(device);
-       } else {
-               *fs_devices_ret = device->fs_devices;
+       if (!IS_ERR(device)) {
                if (new_device_added)
                        btrfs_free_stale_devices(path, device);
        }
@@ -1258,7 +1254,7 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 error_bdev_put:
        blkdev_put(bdev, flags);
 
-       return ret;
+       return device;
 }
 
 static int contains_pending_extent(struct btrfs_transaction *transaction,

diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 9665b84..06d8bb7 100644 (file)
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -403,8 +403,8 @@ blk_status_t btrfs_map_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
                           int mirror_num, int async_submit);
 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
                       fmode_t flags, void *holder);
-int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
-                         struct btrfs_fs_devices **fs_devices_ret);
+struct btrfs_device *btrfs_scan_one_device(const char *path,
+                                          fmode_t flags, void *holder);
 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices);
 void btrfs_free_extra_devids(struct btrfs_fs_devices *fs_devices, int step);
 void btrfs_assign_next_active_device(struct btrfs_fs_info *fs_info,