GFS2: fix d_splice_alias() misuses

Callers of d_splice_alias(dentry, inode) don't need iput(), neither
on success nor on failure.  Either the reference to inode is stored
in a previously negative dentry, or it's dropped.  In either case
inode reference the caller used to hold is consumed.

__gfs2_lookup() does iput() in case when d_splice_alias() has failed.
Double iput() if we ever hit that.  And gfs2_create_inode() ends up
not only with double iput(), but with link count dropped to zero - on
an inode it has just found in directory.

Cc: stable@vger.kernel.org # v3.14+
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 9317ddc1b3c3..fc8ac2ee0667 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -626,8 +626,10 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
         if (!IS_ERR(inode)) {
                 d = d_splice_alias(inode, dentry);
                 error = PTR_ERR(d);
-                if (IS_ERR(d))
+                if (IS_ERR(d)) {
+                        inode = ERR_CAST(d);
                         goto fail_gunlock;
+                }
                 error = 0;
                 if (file) {
                         if (S_ISREG(inode->i_mode)) {
@@ -856,7 +858,6 @@ static struct dentry *__gfs2_lookup(struct inode *dir, struct dentry *dentry,
 
         d = d_splice_alias(inode, dentry);
         if (IS_ERR(d)) {
-                iput(inode);
                 gfs2_glock_dq_uninit(&gh);
                 return d;
         }