diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/ioctl.c | 136 |
1 files changed, 116 insertions, 20 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 7a7d5d4753cd..56bd3ea7fb67 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -28,6 +28,7 @@ #include <linux/iversion.h> #include "ctree.h" #include "disk-io.h" +#include "export.h" #include "transaction.h" #include "btrfs_inode.h" #include "print-tree.h" @@ -2842,7 +2843,8 @@ out: } static noinline int btrfs_ioctl_snap_destroy(struct file *file, - void __user *arg) + void __user *arg, + bool destroy_v2) { struct dentry *parent = file->f_path.dentry; struct btrfs_fs_info *fs_info = btrfs_sb(parent->d_sb); @@ -2851,34 +2853,120 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file, struct inode *inode; struct btrfs_root *root = BTRFS_I(dir)->root; struct btrfs_root *dest = NULL; - struct btrfs_ioctl_vol_args *vol_args; - int namelen; + struct btrfs_ioctl_vol_args *vol_args = NULL; + struct btrfs_ioctl_vol_args_v2 *vol_args2 = NULL; + char *subvol_name, *subvol_name_ptr = NULL; + int subvol_namelen; int err = 0; + bool destroy_parent = false; - if (!S_ISDIR(dir->i_mode)) - return -ENOTDIR; + if (destroy_v2) { + vol_args2 = memdup_user(arg, sizeof(*vol_args2)); + if (IS_ERR(vol_args2)) + return PTR_ERR(vol_args2); - vol_args = memdup_user(arg, sizeof(*vol_args)); - if (IS_ERR(vol_args)) - return PTR_ERR(vol_args); + if (vol_args2->flags & ~BTRFS_SUBVOL_DELETE_ARGS_MASK) { + err = -EOPNOTSUPP; + goto out; + } - vol_args->name[BTRFS_PATH_NAME_MAX] = '\0'; - namelen = strlen(vol_args->name); - if (strchr(vol_args->name, '/') || - strncmp(vol_args->name, "..", namelen) == 0) { - err = -EINVAL; - goto out; + /* + * If SPEC_BY_ID is not set, we are looking for the subvolume by + * name, same as v1 currently does. + */ + if (!(vol_args2->flags & BTRFS_SUBVOL_SPEC_BY_ID)) { + vol_args2->name[BTRFS_SUBVOL_NAME_MAX] = 0; + subvol_name = vol_args2->name; + + err = mnt_want_write_file(file); + if (err) + goto out; + } else { + if (vol_args2->subvolid < BTRFS_FIRST_FREE_OBJECTID) { + err = -EINVAL; + goto out; + } + + err = mnt_want_write_file(file); + if (err) + goto out; + + dentry = btrfs_get_dentry(fs_info->sb, + BTRFS_FIRST_FREE_OBJECTID, + vol_args2->subvolid, 0, 0); + if (IS_ERR(dentry)) { + err = PTR_ERR(dentry); + goto out_drop_write; + } + + /* + * Change the default parent since the subvolume being + * deleted can be outside of the current mount point. + */ + parent = btrfs_get_parent(dentry); + + /* + * At this point dentry->d_name can point to '/' if the + * subvolume we want to destroy is outsite of the + * current mount point, so we need to release the + * current dentry and execute the lookup to return a new + * one with ->d_name pointing to the + * <mount point>/subvol_name. + */ + dput(dentry); + if (IS_ERR(parent)) { + err = PTR_ERR(parent); + goto out_drop_write; + } + dir = d_inode(parent); + + /* + * If v2 was used with SPEC_BY_ID, a new parent was + * allocated since the subvolume can be outside of the + * current mount point. Later on we need to release this + * new parent dentry. + */ + destroy_parent = true; + + subvol_name_ptr = btrfs_get_subvol_name_from_objectid( + fs_info, vol_args2->subvolid); + if (IS_ERR(subvol_name_ptr)) { + err = PTR_ERR(subvol_name_ptr); + goto free_parent; + } + /* subvol_name_ptr is already NULL termined */ + subvol_name = (char *)kbasename(subvol_name_ptr); + } + } else { + vol_args = memdup_user(arg, sizeof(*vol_args)); + if (IS_ERR(vol_args)) + return PTR_ERR(vol_args); + + vol_args->name[BTRFS_PATH_NAME_MAX] = 0; + subvol_name = vol_args->name; + + err = mnt_want_write_file(file); + if (err) + goto out; } - err = mnt_want_write_file(file); - if (err) - goto out; + subvol_namelen = strlen(subvol_name); + if (strchr(subvol_name, '/') || + strncmp(subvol_name, "..", subvol_namelen) == 0) { + err = -EINVAL; + goto free_subvol_name; + } + + if (!S_ISDIR(dir->i_mode)) { + err = -ENOTDIR; + goto free_subvol_name; + } err = down_write_killable_nested(&dir->i_rwsem, I_MUTEX_PARENT); if (err == -EINTR) - goto out_drop_write; - dentry = lookup_one_len(vol_args->name, parent, namelen); + goto free_subvol_name; + dentry = lookup_one_len(subvol_name, parent, subvol_namelen); if (IS_ERR(dentry)) { err = PTR_ERR(dentry); goto out_unlock_dir; @@ -2947,9 +3035,15 @@ out_dput: dput(dentry); out_unlock_dir: inode_unlock(dir); +free_subvol_name: + kfree(subvol_name_ptr); +free_parent: + if (destroy_parent) + dput(parent); out_drop_write: mnt_drop_write_file(file); out: + kfree(vol_args2); kfree(vol_args); return err; } @@ -5474,7 +5568,9 @@ long btrfs_ioctl(struct file *file, unsigned int case BTRFS_IOC_SUBVOL_CREATE_V2: return btrfs_ioctl_snap_create_v2(file, argp, 1); case BTRFS_IOC_SNAP_DESTROY: - return btrfs_ioctl_snap_destroy(file, argp); + return btrfs_ioctl_snap_destroy(file, argp, false); + case BTRFS_IOC_SNAP_DESTROY_V2: + return btrfs_ioctl_snap_destroy(file, argp, true); case BTRFS_IOC_SUBVOL_GETFLAGS: return btrfs_ioctl_subvol_getflags(file, argp); case BTRFS_IOC_SUBVOL_SETFLAGS: |