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Diffstat (limited to 'fs/btrfs/qgroup.c')
-rw-r--r--fs/btrfs/qgroup.c88
1 files changed, 78 insertions, 10 deletions
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 77c54749f432..87bd37b70738 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -11,6 +11,7 @@
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/btrfs.h>
+#include <linux/sched/mm.h>
#include "ctree.h"
#include "transaction.h"
@@ -497,13 +498,13 @@ next2:
break;
}
out:
+ btrfs_free_path(path);
fs_info->qgroup_flags |= flags;
if (!(fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_ON))
clear_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
else if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN &&
ret >= 0)
ret = qgroup_rescan_init(fs_info, rescan_progress, 0);
- btrfs_free_path(path);
if (ret < 0) {
ulist_free(fs_info->qgroup_ulist);
@@ -936,6 +937,7 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info)
struct btrfs_key found_key;
struct btrfs_qgroup *qgroup = NULL;
struct btrfs_trans_handle *trans = NULL;
+ struct ulist *ulist = NULL;
int ret = 0;
int slot;
@@ -943,8 +945,8 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info)
if (fs_info->quota_root)
goto out;
- fs_info->qgroup_ulist = ulist_alloc(GFP_KERNEL);
- if (!fs_info->qgroup_ulist) {
+ ulist = ulist_alloc(GFP_KERNEL);
+ if (!ulist) {
ret = -ENOMEM;
goto out;
}
@@ -952,6 +954,22 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info)
ret = btrfs_sysfs_add_qgroups(fs_info);
if (ret < 0)
goto out;
+
+ /*
+ * Unlock qgroup_ioctl_lock before starting the transaction. This is to
+ * avoid lock acquisition inversion problems (reported by lockdep) between
+ * qgroup_ioctl_lock and the vfs freeze semaphores, acquired when we
+ * start a transaction.
+ * After we started the transaction lock qgroup_ioctl_lock again and
+ * check if someone else created the quota root in the meanwhile. If so,
+ * just return success and release the transaction handle.
+ *
+ * Also we don't need to worry about someone else calling
+ * btrfs_sysfs_add_qgroups() after we unlock and getting an error because
+ * that function returns 0 (success) when the sysfs entries already exist.
+ */
+ mutex_unlock(&fs_info->qgroup_ioctl_lock);
+
/*
* 1 for quota root item
* 1 for BTRFS_QGROUP_STATUS item
@@ -961,12 +979,20 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info)
* would be a lot of overkill.
*/
trans = btrfs_start_transaction(tree_root, 2);
+
+ mutex_lock(&fs_info->qgroup_ioctl_lock);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
trans = NULL;
goto out;
}
+ if (fs_info->quota_root)
+ goto out;
+
+ fs_info->qgroup_ulist = ulist;
+ ulist = NULL;
+
/*
* initially create the quota tree
*/
@@ -1124,11 +1150,14 @@ out:
if (ret) {
ulist_free(fs_info->qgroup_ulist);
fs_info->qgroup_ulist = NULL;
- if (trans)
- btrfs_end_transaction(trans);
btrfs_sysfs_del_qgroups(fs_info);
}
mutex_unlock(&fs_info->qgroup_ioctl_lock);
+ if (ret && trans)
+ btrfs_end_transaction(trans);
+ else if (trans)
+ ret = btrfs_end_transaction(trans);
+ ulist_free(ulist);
return ret;
}
@@ -1141,19 +1170,29 @@ int btrfs_quota_disable(struct btrfs_fs_info *fs_info)
mutex_lock(&fs_info->qgroup_ioctl_lock);
if (!fs_info->quota_root)
goto out;
+ mutex_unlock(&fs_info->qgroup_ioctl_lock);
/*
* 1 For the root item
*
* We should also reserve enough items for the quota tree deletion in
* btrfs_clean_quota_tree but this is not done.
+ *
+ * Also, we must always start a transaction without holding the mutex
+ * qgroup_ioctl_lock, see btrfs_quota_enable().
*/
trans = btrfs_start_transaction(fs_info->tree_root, 1);
+
+ mutex_lock(&fs_info->qgroup_ioctl_lock);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
+ trans = NULL;
goto out;
}
+ if (!fs_info->quota_root)
+ goto out;
+
clear_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
btrfs_qgroup_wait_for_completion(fs_info, false);
spin_lock(&fs_info->qgroup_lock);
@@ -1167,13 +1206,13 @@ int btrfs_quota_disable(struct btrfs_fs_info *fs_info)
ret = btrfs_clean_quota_tree(trans, quota_root);
if (ret) {
btrfs_abort_transaction(trans, ret);
- goto end_trans;
+ goto out;
}
ret = btrfs_del_root(trans, &quota_root->root_key);
if (ret) {
btrfs_abort_transaction(trans, ret);
- goto end_trans;
+ goto out;
}
list_del(&quota_root->dirty_list);
@@ -1185,10 +1224,13 @@ int btrfs_quota_disable(struct btrfs_fs_info *fs_info)
btrfs_put_root(quota_root);
-end_trans:
- ret = btrfs_end_transaction(trans);
out:
mutex_unlock(&fs_info->qgroup_ioctl_lock);
+ if (ret && trans)
+ btrfs_end_transaction(trans);
+ else if (trans)
+ ret = btrfs_end_transaction(trans);
+
return ret;
}
@@ -1324,13 +1366,17 @@ int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
struct btrfs_qgroup *member;
struct btrfs_qgroup_list *list;
struct ulist *tmp;
+ unsigned int nofs_flag;
int ret = 0;
/* Check the level of src and dst first */
if (btrfs_qgroup_level(src) >= btrfs_qgroup_level(dst))
return -EINVAL;
+ /* We hold a transaction handle open, must do a NOFS allocation. */
+ nofs_flag = memalloc_nofs_save();
tmp = ulist_alloc(GFP_KERNEL);
+ memalloc_nofs_restore(nofs_flag);
if (!tmp)
return -ENOMEM;
@@ -1387,10 +1433,14 @@ static int __del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
struct btrfs_qgroup_list *list;
struct ulist *tmp;
bool found = false;
+ unsigned int nofs_flag;
int ret = 0;
int ret2;
+ /* We hold a transaction handle open, must do a NOFS allocation. */
+ nofs_flag = memalloc_nofs_save();
tmp = ulist_alloc(GFP_KERNEL);
+ memalloc_nofs_restore(nofs_flag);
if (!tmp)
return -ENOMEM;
@@ -3512,6 +3562,7 @@ static int try_flush_qgroup(struct btrfs_root *root)
{
struct btrfs_trans_handle *trans;
int ret;
+ bool can_commit = true;
/*
* We don't want to run flush again and again, so if there is a running
@@ -3523,6 +3574,20 @@ static int try_flush_qgroup(struct btrfs_root *root)
return 0;
}
+ /*
+ * If current process holds a transaction, we shouldn't flush, as we
+ * assume all space reservation happens before a transaction handle is
+ * held.
+ *
+ * But there are cases like btrfs_delayed_item_reserve_metadata() where
+ * we try to reserve space with one transction handle already held.
+ * In that case we can't commit transaction, but at least try to end it
+ * and hope the started data writes can free some space.
+ */
+ if (current->journal_info &&
+ current->journal_info != BTRFS_SEND_TRANS_STUB)
+ can_commit = false;
+
ret = btrfs_start_delalloc_snapshot(root);
if (ret < 0)
goto out;
@@ -3534,7 +3599,10 @@ static int try_flush_qgroup(struct btrfs_root *root)
goto out;
}
- ret = btrfs_commit_transaction(trans);
+ if (can_commit)
+ ret = btrfs_commit_transaction(trans);
+ else
+ ret = btrfs_end_transaction(trans);
out:
clear_bit(BTRFS_ROOT_QGROUP_FLUSHING, &root->state);
wake_up(&root->qgroup_flush_wait);
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-01 17:42:27 +0100