linux-kernel - btrfs: drop inode reference count on error path

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Date:   Wed, 17 Apr 2019 10:23:30 +0800
From:   Pan Bian <bianpan2016@....com>
To:     Chris Mason <clm@...com>, Josef Bacik <josef@...icpanda.com>,
        David Sterba <dsterba@...e.com>
Cc:     linux-btrfs@...r.kernel.org, linux-kernel@...r.kernel.org,
        Pan Bian <bianpan2016@....com>
Subject: btrfs: drop inode reference count on error path

The reference count of inode is incremented by ihold. It should be
dropped if not used. However, the reference count is not dropped if
error occurs during updating the inode or deleting orphan items. This
patch fixes the bug.

Signed-off-by: Pan Bian <bianpan2016@....com>
---
 fs/btrfs/inode.c | 45 ++++++++++++++++++++++-----------------------
 1 file changed, 22 insertions(+), 23 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 82fdda8..400c914 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6580,6 +6580,7 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
 	u64 index;
 	int err;
 	int drop_inode = 0;
+	int ret;
 
 	/* do not allow sys_link's with other subvols of the same device */
 	if (root->root_key.objectid != BTRFS_I(inode)->root->root_key.objectid)
@@ -6616,32 +6617,30 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
 	err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
 			1, index);
 
-	if (err) {
-		drop_inode = 1;
-	} else {
-		struct dentry *parent = dentry->d_parent;
-		int ret;
+	drop_inode = 1;
+	if (err)
+		goto fail;
 
-		err = btrfs_update_inode(trans, root, inode);
+	err = btrfs_update_inode(trans, root, inode);
+	if (err)
+		goto fail;
+	if (inode->i_nlink == 1) {
+		/*
+		 * If new hard link count is 1, it's a file created
+		 * with open(2) O_TMPFILE flag.
+		 */
+		err = btrfs_orphan_del(trans, BTRFS_I(inode));
 		if (err)
 			goto fail;
-		if (inode->i_nlink == 1) {
-			/*
-			 * If new hard link count is 1, it's a file created
-			 * with open(2) O_TMPFILE flag.
-			 */
-			err = btrfs_orphan_del(trans, BTRFS_I(inode));
-			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);
-		if (ret == BTRFS_NEED_TRANS_COMMIT) {
-			err = btrfs_commit_transaction(trans);
-			trans = NULL;
-		}
+	}
+	BTRFS_I(inode)->last_link_trans = trans->transid;
+	d_instantiate(dentry, inode);
+	drop_inode = 0;
+	ret = btrfs_log_new_name(trans, BTRFS_I(inode), NULL, dentry->d_parent,
+			true, NULL);
+	if (ret == BTRFS_NEED_TRANS_COMMIT) {
+		err = btrfs_commit_transaction(trans);
+		trans = NULL;
 	}
 
 fail:
-- 
2.7.4