btrfs: qgroup: Introduce new functions to reserve/free metadata

Introduce new functions btrfs_qgroup_reserve/free_meta() to reserve/free
metadata reserved space.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 49bc792..9df8f01 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1943,6 +1943,9 @@ struct btrfs_root {
        int send_in_progress;
        struct btrfs_subvolume_writers *subv_writers;
        atomic_t will_be_snapshoted;
+
+       /* For qgroup metadata space reserve */
+       atomic_t qgroup_meta_rsv;
 };
 
 struct btrfs_ioctl_defrag_range_args {

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index bcbb596..0e0544e 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1267,6 +1267,7 @@ static void __setup_root(u32 nodesize, u32 sectorsize, u32 stripesize,
        atomic_set(&root->orphan_inodes, 0);
        atomic_set(&root->refs, 1);
        atomic_set(&root->will_be_snapshoted, 0);
+       atomic_set(&root->qgroup_meta_rsv, 0);
        root->log_transid = 0;
        root->log_transid_committed = -1;
        root->last_log_commit = 0;

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 75d8e58..897a49d 100644 (file)
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -2594,3 +2594,43 @@ int btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len)
 {
        return __btrfs_qgroup_release_data(inode, start, len, 0);
 }
+
+int btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes)
+{
+       int ret;
+
+       if (!root->fs_info->quota_enabled || !is_fstree(root->objectid) ||
+           num_bytes == 0)
+               return 0;
+
+       BUG_ON(num_bytes != round_down(num_bytes, root->nodesize));
+       ret = btrfs_qgroup_reserve(root, num_bytes);
+       if (ret < 0)
+               return ret;
+       atomic_add(num_bytes, &root->qgroup_meta_rsv);
+       return ret;
+}
+
+void btrfs_qgroup_free_meta_all(struct btrfs_root *root)
+{
+       int reserved;
+
+       if (!root->fs_info->quota_enabled || !is_fstree(root->objectid))
+               return;
+
+       reserved = atomic_xchg(&root->qgroup_meta_rsv, 0);
+       if (reserved == 0)
+               return;
+       btrfs_qgroup_free(root, reserved);
+}
+
+void btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes)
+{
+       if (!root->fs_info->quota_enabled || !is_fstree(root->objectid))
+               return;
+
+       BUG_ON(num_bytes != round_down(num_bytes, root->nodesize));
+       WARN_ON(atomic_read(&root->qgroup_meta_rsv) < num_bytes);
+       atomic_sub(num_bytes, &root->qgroup_meta_rsv);
+       btrfs_qgroup_free(root, num_bytes);
+}

diff --git a/fs/btrfs/qgroup.h b/fs/btrfs/qgroup.h
index 80924ae..7d1c87c 100644 (file)
--- a/fs/btrfs/qgroup.h
+++ b/fs/btrfs/qgroup.h
@@ -101,4 +101,8 @@ int btrfs_verify_qgroup_counts(struct btrfs_fs_info *fs_info, u64 qgroupid,
 int btrfs_qgroup_reserve_data(struct inode *inode, u64 start, u64 len);
 int btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len);
 int btrfs_qgroup_free_data(struct inode *inode, u64 start, u64 len);
+
+int btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes);
+void btrfs_qgroup_free_meta_all(struct btrfs_root *root);
+void btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes);
 #endif /* __BTRFS_QGROUP__ */