@@ -147,6 +147,12 @@ struct btrfs_inode {
u64 last_unlink_trans;
/*
+ * Track the transaction id of the last transaction used to create a
+ * hard link for the inode. This is used by the log tree (fsync).
+ */
+ u64 last_link_trans;
+
+ /*
* Number of bytes outstanding that are going to need csums. This is
* used in ENOSPC accounting.
*/
@@ -6651,6 +6651,7 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
if (err)
goto fail;
}
+ BTRFS_I(inode)->last_link_trans = trans->transid;
d_instantiate(dentry, inode);
ret = btrfs_log_new_name(trans, BTRFS_I(inode), NULL, parent,
true, NULL);
@@ -9179,6 +9180,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
ei->index_cnt = (u64)-1;
ei->dir_index = 0;
ei->last_unlink_trans = 0;
+ ei->last_link_trans = 0;
ei->last_log_commit = 0;
spin_lock_init(&ei->lock);
@@ -5760,6 +5760,22 @@ static int btrfs_log_inode_parent(struct btrfs_trans_handle *trans,
goto end_trans;
}
+ /*
+ * If a new hard link was added to the inode in the current transaction
+ * and its link count is now greater than 1, we need to fallback to a
+ * transaction commit, otherwise we can end up not logging all its new
+ * parents for all the hard links. Here just from the dentry used to
+ * fsync, we can not visit the ancestor inodes for all the other hard
+ * links to figure out if any is new, so we fallback to a transaction
+ * commit (instead of adding a lot of complexity of scanning a btree,
+ * since this scenario is not a common use case).
+ */
+ if (inode->vfs_inode.i_nlink > 1 &&
+ inode->last_link_trans > last_committed) {
+ ret = -EMLINK;
+ goto end_trans;
+ }
+
while (1) {
if (!parent || d_really_is_negative(parent) || sb != parent->d_sb)
break;