From: Josef Bacik josef@toxicpanda.com
[ Upstream commit faa775c41d655a4786e9d53cb075a77bb5a75f66 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/volumes.c | 96 ++++++++++++++++++++++++++++++---------------- fs/btrfs/volumes.h | 4 ++ 2 files changed, 68 insertions(+), 32 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 53417a1c5402..8d09e6d442b2 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -2361,45 +2361,81 @@ 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; @@ -2409,18 +2445,14 @@ 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; }
/* diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index f3b1380f45ad..d1df03f77e29 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -487,9 +487,13 @@ void btrfs_assign_next_active_device(struct btrfs_device *device, struct btrfs_device *btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info, u64 devid, const char *devpath); +int btrfs_get_dev_args_from_path(struct btrfs_fs_info *fs_info, + struct btrfs_dev_lookup_args *args, + const char *path); struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info, const u64 *devid, const u8 *uuid); +void btrfs_put_dev_args_from_path(struct btrfs_dev_lookup_args *args); void btrfs_free_device(struct btrfs_device *device); int btrfs_rm_device(struct btrfs_fs_info *fs_info, const char *device_path, u64 devid,