diff options
author | Josef Bacik <josef@toxicpanda.com> | 2021-10-05 23:12:43 +0300 |
---|---|---|
committer | David Sterba <dsterba@suse.com> | 2021-10-26 20:08:07 +0300 |
commit | faa775c41d655a4786e9d53cb075a77bb5a75f66 (patch) | |
tree | 72087feb56f555f84f6632d57650b84049482809 /fs/btrfs/volumes.c | |
parent | 562d7b1512f7369a19bca2883e2e8672d78f0481 (diff) | |
download | linux-faa775c41d655a4786e9d53cb075a77bb5a75f66.tar.xz |
btrfs: add a btrfs_get_dev_args_from_path helper
We are going to want to populate our device lookup args outside of any
locks and then do the actual device lookup later, so add a helper to do
this work and make btrfs_find_device_by_devspec() use this helper for
now.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/volumes.c')
-rw-r--r-- | fs/btrfs/volumes.c | 96 |
1 files changed, 64 insertions, 32 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index eddd2e50cb65..340583942d22 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -2325,45 +2325,81 @@ void btrfs_destroy_dev_replace_tgtdev(struct btrfs_device *tgtdev) btrfs_free_device(tgtdev); } -static struct btrfs_device *btrfs_find_device_by_path( - struct btrfs_fs_info *fs_info, const char *device_path) +/** + * Populate args from device at path + * + * @fs_info: the filesystem + * @args: the args to populate + * @path: the path to the device + * + * This will read the super block of the device at @path and populate @args with + * the devid, fsid, and uuid. This is meant to be used for ioctls that need to + * lookup a device to operate on, but need to do it before we take any locks. + * This properly handles the special case of "missing" that a user may pass in, + * and does some basic sanity checks. The caller must make sure that @path is + * properly NUL terminated before calling in, and must call + * btrfs_put_dev_args_from_path() in order to free up the temporary fsid and + * uuid buffers. + * + * Return: 0 for success, -errno for failure + */ +int btrfs_get_dev_args_from_path(struct btrfs_fs_info *fs_info, + struct btrfs_dev_lookup_args *args, + const char *path) { - BTRFS_DEV_LOOKUP_ARGS(args); - int ret = 0; struct btrfs_super_block *disk_super; struct block_device *bdev; - struct btrfs_device *device; + int ret; - ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ, - fs_info->bdev_holder, 0, &bdev, &disk_super); - if (ret) - return ERR_PTR(ret); + if (!path || !path[0]) + return -EINVAL; + if (!strcmp(path, "missing")) { + args->missing = true; + return 0; + } + + args->uuid = kzalloc(BTRFS_UUID_SIZE, GFP_KERNEL); + args->fsid = kzalloc(BTRFS_FSID_SIZE, GFP_KERNEL); + if (!args->uuid || !args->fsid) { + btrfs_put_dev_args_from_path(args); + return -ENOMEM; + } - args.devid = btrfs_stack_device_id(&disk_super->dev_item); - args.uuid = disk_super->dev_item.uuid; + ret = btrfs_get_bdev_and_sb(path, FMODE_READ, fs_info->bdev_holder, 0, + &bdev, &disk_super); + if (ret) + return ret; + args->devid = btrfs_stack_device_id(&disk_super->dev_item); + memcpy(args->uuid, disk_super->dev_item.uuid, BTRFS_UUID_SIZE); if (btrfs_fs_incompat(fs_info, METADATA_UUID)) - args.fsid = disk_super->metadata_uuid; + memcpy(args->fsid, disk_super->metadata_uuid, BTRFS_FSID_SIZE); else - args.fsid = disk_super->fsid; - - device = btrfs_find_device(fs_info->fs_devices, &args); - + memcpy(args->fsid, disk_super->fsid, BTRFS_FSID_SIZE); btrfs_release_disk_super(disk_super); - if (!device) - device = ERR_PTR(-ENOENT); blkdev_put(bdev, FMODE_READ); - return device; + return 0; } /* - * Lookup a device given by device id, or the path if the id is 0. + * Only use this jointly with btrfs_get_dev_args_from_path() because we will + * allocate our ->uuid and ->fsid pointers, everybody else uses local variables + * that don't need to be freed. */ +void btrfs_put_dev_args_from_path(struct btrfs_dev_lookup_args *args) +{ + kfree(args->uuid); + kfree(args->fsid); + args->uuid = NULL; + args->fsid = NULL; +} + struct btrfs_device *btrfs_find_device_by_devspec( struct btrfs_fs_info *fs_info, u64 devid, const char *device_path) { BTRFS_DEV_LOOKUP_ARGS(args); struct btrfs_device *device; + int ret; if (devid) { args.devid = devid; @@ -2373,18 +2409,14 @@ struct btrfs_device *btrfs_find_device_by_devspec( return device; } - if (!device_path || !device_path[0]) - return ERR_PTR(-EINVAL); - - if (strcmp(device_path, "missing") == 0) { - args.missing = true; - device = btrfs_find_device(fs_info->fs_devices, &args); - if (!device) - return ERR_PTR(-ENOENT); - return device; - } - - return btrfs_find_device_by_path(fs_info, device_path); + ret = btrfs_get_dev_args_from_path(fs_info, &args, device_path); + if (ret) + return ERR_PTR(ret); + device = btrfs_find_device(fs_info->fs_devices, &args); + btrfs_put_dev_args_from_path(&args); + if (!device) + return ERR_PTR(-ENOENT); + return device; } /* |