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>

diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 9317ddc..fc8ac2e 100644 (file)
--- 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;
        }