eCryptfs: Fix new inode race condition

Only unlock and d_add() new inodes after the plaintext inode size has
been read from the lower filesystem. This fixes a race condition that
was sometimes seen during a multi-job kernel build in an eCryptfs mount.

https://bugzilla.kernel.org/show_bug.cgi?id=36002

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Reported-by: David <david@unsolicited.net>
Tested-by: David <david@unsolicited.net>

1 files changed, 3 insertions, 3 deletions

diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 7c697abab396..943a4f55ed6d 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -135,12 +135,12 @@ static int ecryptfs_init_lower_file(struct dentry *dentry,
         return rc;
 }
 
-int ecryptfs_get_lower_file(struct dentry *dentry)
+int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
 {
-        struct ecryptfs_inode_info *inode_info =
-                ecryptfs_inode_to_private(dentry->d_inode);
+        struct ecryptfs_inode_info *inode_info;
         int count, rc = 0;
 
+        inode_info = ecryptfs_inode_to_private(inode);
         mutex_lock(&inode_info->lower_file_mutex);
         count = atomic_inc_return(&inode_info->lower_file_count);
         if (WARN_ON_ONCE(count < 1))