From 4ea7772f828a2f1cf6fbf96a3e6f99ae149d2724 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Mon, 23 Dec 2013 22:02:16 +0100 Subject: [PATCH] udf: Fix lockdep warning from udf_symlink() Lockdep is complaining about UDF: ============================================= [ INFO: possible recursive locking detected ] 3.12.0+ #16 Not tainted --------------------------------------------- ln/7386 is trying to acquire lock: (&ei->i_data_sem){+.+...}, at: [] udf_get_block+0x8d/0x130 but task is already holding lock: (&ei->i_data_sem){+.+...}, at: [] udf_symlink+0x8d/0x690 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&ei->i_data_sem); lock(&ei->i_data_sem); *** DEADLOCK *** This is because we hold i_data_sem of the symlink inode while calling udf_add_entry() for the directory. I don't think this can ever lead to deadlocks since we never hold i_data_sem for two inodes in any other place. The fix is simple - move unlock of i_data_sem for symlink inode up. We don't need it for anything when linking symlink inode to directory. Reported-by: Christoph Hellwig Signed-off-by: Jan Kara --- fs/udf/namei.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/udf/namei.c b/fs/udf/namei.c index 5f6fc17d6bc5..9737cba1357d 100644 --- a/fs/udf/namei.c +++ b/fs/udf/namei.c @@ -1010,6 +1010,7 @@ static int udf_symlink(struct inode *dir, struct dentry *dentry, else udf_truncate_tail_extent(inode); mark_inode_dirty(inode); + up_write(&iinfo->i_data_sem); fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err); if (!fi) @@ -1023,7 +1024,6 @@ static int udf_symlink(struct inode *dir, struct dentry *dentry, udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL); if (UDF_I(dir)->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) mark_inode_dirty(dir); - up_write(&iinfo->i_data_sem); if (fibh.sbh != fibh.ebh) brelse(fibh.ebh); brelse(fibh.sbh);