This patch introduces two new ioctls to create, and remove qgroups. These
offer a somewhat more intuitive set of operations with the opportunity
to add flags that gate to unintentional manipulation of qgroups.
The create qgroup ioctl has a a new semantic which level-0 qgroups cannot
be created unless a matching subvolume ID is created.
The delete qgroup ioctl has the new semantic that it will not let you
delete a currently utilized (referenced by a subvolume) level-0
qgroup unless you pass the BTRFS_QGROUP_NO_SUBVOL_CHECK flag.
Signed-off-by: Sargun Dhillon <sar...@sargun.me>
---
fs/btrfs/ioctl.c | 100 ++++++++++++++++++++++++++++++++++++++++++++-
fs/btrfs/qgroup.c | 76 +++++++++++++++++++++++++++++++---
fs/btrfs/qgroup.h | 6 ++-
include/uapi/linux/btrfs.h | 22 ++++++++++
4 files changed, 195 insertions(+), 9 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index e176375..78c8321 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4922,6 +4922,98 @@ static long btrfs_ioctl_qgroup_assign(struct file *file,
void __user *arg)
return ret;
}
+static long btrfs_ioctl_qgroup_create_v2(struct file *file, void __user *arg)
+{
+ struct btrfs_ioctl_qgroup_create_args_v2 create_args;
+ struct btrfs_trans_handle *trans;
+ struct btrfs_fs_info *fs_info;
+ struct btrfs_root *root;
+ struct inode *inode;
+ int ret;
+ int err;
+
+ inode = file_inode(file);
+ fs_info = btrfs_sb(inode->i_sb);
+ root = BTRFS_I(inode)->root;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ ret = copy_from_user(&create_args, arg, sizeof(create_args));
+ if (ret)
+ return ret;
+
+ if (!create_args.qgroupid)
+ return -EINVAL;
+
+ ret = mnt_want_write_file(file);
+ if (ret)
+ return ret;
+
+ trans = btrfs_join_transaction(root);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ goto out;
+ }
+
+ ret = btrfs_create_qgroup(trans, fs_info, create_args.qgroupid, 1);
+ err = btrfs_end_transaction(trans);
+
+ if (err && !ret)
+ ret = err;
+
+out:
+ mnt_drop_write_file(file);
+ return ret;
+}
+
+static long btrfs_ioctl_qgroup_remove_v2(struct file *file, void __user *arg)
+{
+ struct btrfs_ioctl_qgroup_remove_args_v2 remove_args;
+ struct btrfs_trans_handle *trans;
+ struct btrfs_fs_info *fs_info;
+ struct btrfs_root *root;
+ struct inode *inode;
+ int check;
+ int ret;
+ int err;
+
+ inode = file_inode(file);
+ fs_info = btrfs_sb(inode->i_sb);
+ root = BTRFS_I(inode)->root;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ ret = copy_from_user(&remove_args, arg, sizeof(remove_args));
+ if (ret)
+ return ret;
+
+ if (!remove_args.qgroupid)
+ return -EINVAL;
+ check = !(remove_args.flags & BTRFS_QGROUP_NO_SUBVOL_CHECK);
+
+ ret = mnt_want_write_file(file);
+ if (ret)
+ return ret;
+
+ trans = btrfs_join_transaction(root);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ goto out;
+ }
+
+ ret = btrfs_remove_qgroup(trans, fs_info, remove_args.qgroupid, check);
+ err = btrfs_end_transaction(trans);
+
+ if (err && !ret)
+ ret = err;
+
+out:
+ mnt_drop_write_file(file);
+ return ret;
+}
+
static long btrfs_ioctl_qgroup_create(struct file *file, void __user *arg)
{
struct inode *inode = file_inode(file);
@@ -4958,9 +5050,9 @@ static long btrfs_ioctl_qgroup_create(struct file *file,
void __user *arg)
/* FIXME: check if the IDs really exist */
if (sa->create) {
- ret = btrfs_create_qgroup(trans, fs_info, sa->qgroupid);
+ ret = btrfs_create_qgroup(trans, fs_info, sa->qgroupid, 0);
} else {
- ret = btrfs_remove_qgroup(trans, fs_info, sa->qgroupid);
+ ret = btrfs_remove_qgroup(trans, fs_info, sa->qgroupid, 0);
}
err = btrfs_end_transaction(trans);
@@ -5632,6 +5724,10 @@ long btrfs_ioctl(struct file *file, unsigned int
return btrfs_ioctl_get_features(file, argp);
case BTRFS_IOC_SET_FEATURES:
return btrfs_ioctl_set_features(file, argp);
+ case BTRFS_IOC_QGROUP_CREATE_V2:
+ return btrfs_ioctl_qgroup_create_v2(file, argp);
+ case BTRFS_IOC_QGROUP_REMOVE_V2:
+ return btrfs_ioctl_qgroup_remove_v2(file, argp);
}
return -ENOTTY;
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index d39ffcc..ba8a6ee 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1247,8 +1247,51 @@ int btrfs_del_qgroup_relation(struct btrfs_trans_handle
*trans,
return ret;
}
+/*
+ * Meant to only operate on level-0 qroupid.
+ *
+ * It returns 1 if a matching subvolume is found; 0 if none is found.
+ * < 0 if there is an error.
+ */
+static int btrfs_subvolume_exists(struct btrfs_fs_info *fs_info, u64 qgroupid)
+{
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ int err, ret = 0;
+
+ if (qgroupid == BTRFS_FS_TREE_OBJECTID)
+ return 1;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = qgroupid;
+ key.type = BTRFS_ROOT_BACKREF_KEY;
+ key.offset = 0;
+
+ err = btrfs_search_slot_for_read(fs_info->tree_root, &key, path, 1, 0);
+ if (err == 1)
+ goto out;
+
+ if (err) {
+ ret = err;
+ goto out;
+ }
+
+ btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
+ if (key.objectid != qgroupid || key.type != BTRFS_ROOT_BACKREF_KEY)
+ goto out;
+
+ ret = 1;
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
int btrfs_create_qgroup(struct btrfs_trans_handle *trans,
- struct btrfs_fs_info *fs_info, u64 qgroupid)
+ struct btrfs_fs_info *fs_info, u64 qgroupid,
+ int check_subvol_exists)
{
struct btrfs_root *quota_root;
struct btrfs_qgroup *qgroup;
@@ -1260,12 +1303,23 @@ int btrfs_create_qgroup(struct btrfs_trans_handle
*trans,
ret = -EINVAL;
goto out;
}
+
qgroup = find_qgroup_rb(fs_info, qgroupid);
if (qgroup) {
ret = -EEXIST;
goto out;
}
+ if (check_subvol_exists && btrfs_qgroup_level(qgroupid) == 0) {
+ ret = btrfs_subvolume_exists(fs_info, qgroupid);
+ if (ret < 0)
+ goto out;
+ if (!ret) {
+ ret = -ENOENT;
+ goto out;
+ }
+ }
+
ret = add_qgroup_item(trans, quota_root, qgroupid);
if (ret)
goto out;
@@ -1282,7 +1336,8 @@ int btrfs_create_qgroup(struct btrfs_trans_handle *trans,
}
int btrfs_remove_qgroup(struct btrfs_trans_handle *trans,
- struct btrfs_fs_info *fs_info, u64 qgroupid)
+ struct btrfs_fs_info *fs_info, u64 qgroupid,
+ int check_subvol_exists)
{
struct btrfs_root *quota_root;
struct btrfs_qgroup *qgroup;
@@ -1300,13 +1355,24 @@ int btrfs_remove_qgroup(struct btrfs_trans_handle
*trans,
if (!qgroup) {
ret = -ENOENT;
goto out;
- } else {
- /* check if there are no children of this qgroup */
- if (!list_empty(&qgroup->members)) {
+ }
+
+ if (check_subvol_exists && btrfs_qgroup_level(qgroupid) == 0) {
+ ret = btrfs_subvolume_exists(fs_info, qgroupid);
+ if (ret < 0)
+ goto out;
+ if (ret) {
ret = -EBUSY;
goto out;
}
}
+
+ /* check if there are no children of this qgroup */
+ if (!list_empty(&qgroup->members)) {
+ ret = -EBUSY;
+ goto out;
+ }
+
ret = del_qgroup_item(trans, quota_root, qgroupid);
if (ret && ret != -ENOENT)
diff --git a/fs/btrfs/qgroup.h b/fs/btrfs/qgroup.h
index fe04d3f..8702d74 100644
--- a/fs/btrfs/qgroup.h
+++ b/fs/btrfs/qgroup.h
@@ -125,9 +125,11 @@ int btrfs_add_qgroup_relation(struct btrfs_trans_handle
*trans,
int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 src, u64 dst);
int btrfs_create_qgroup(struct btrfs_trans_handle *trans,
- struct btrfs_fs_info *fs_info, u64 qgroupid);
+ struct btrfs_fs_info *fs_info, u64 qgroupid,
+ int check_subvol_exists);
int btrfs_remove_qgroup(struct btrfs_trans_handle *trans,
- struct btrfs_fs_info *fs_info, u64 qgroupid);
+ struct btrfs_fs_info *fs_info, u64 qgroupid,
+ int check_subvol_exists);
int btrfs_limit_qgroup(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 qgroupid,
struct btrfs_qgroup_limit *limit);
diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index a456e53..c073854 100644
--- a/include/uapi/linux/btrfs.h
+++ b/include/uapi/linux/btrfs.h
@@ -653,6 +653,24 @@ struct btrfs_ioctl_qgroup_create_args {
__u64 create;
__u64 qgroupid;
};
+
+struct btrfs_ioctl_qgroup_create_args_v2 {
+ __u64 qgroupid;
+ __u64 flags;
+ __u64 reserved[16];
+};
+
+/*
+ * Allows for the deletion of qgroups even if they are associated with active
+ * volumes.
+ */
+#define BTRFS_QGROUP_NO_SUBVOL_CHECK (1ULL << 0)
+struct btrfs_ioctl_qgroup_remove_args_v2 {
+ __u64 qgroupid;
+ __u64 flags;
+ __u64 reserved[16];
+};
+
struct btrfs_ioctl_timespec {
__u64 sec;
__u32 nsec;
@@ -818,5 +836,9 @@ enum btrfs_err_code {
struct btrfs_ioctl_feature_flags[3])
#define BTRFS_IOC_RM_DEV_V2 _IOW(BTRFS_IOCTL_MAGIC, 58, \
struct btrfs_ioctl_vol_args_v2)
+#define BTRFS_IOC_QGROUP_CREATE_V2 _IOW(BTRFS_IOCTL_MAGIC, 59, \
+ struct
btrfs_ioctl_qgroup_create_args_v2)
+#define BTRFS_IOC_QGROUP_REMOVE_V2 _IOW(BTRFS_IOCTL_MAGIC, 60, \
+ struct
btrfs_ioctl_qgroup_remove_args_v2)
#endif /* _UAPI_LINUX_BTRFS_H */
--
2.9.3
--
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