xfs: fix memory leak in xfs_dqinode_metadir_create()

xfs: fix memory leak in xfs_dqinode_metadir_create()

If xfs_metadir_create() fails in xfs_dqinode_metadir_create(), the current
code returns directly, leaking the allocated update and transaction state.
If the subsequent commit fails, the caller-owned inode reference is left
behind.

Fix this memory leak by routing the create failure path through
xfs_metadir_cancel().  For both create and commit failures, finish and
release any inode returned to the caller, mirroring the unwind pattern in
xfs_metadir_mkdir().

The bug was first flagged by an experimental analysis tool we are
developing for kernel memory-management bugs while analyzing
v6.13-rc1. The tool is still under development and is not yet publicly
available. Manual inspection confirms that the bug is still
present in v7.1.1.

An x86_64 allyesconfig build showed no new warnings. Runtime validation
used kprobe fault injection during `mount -o uquota` on a metadir XFS
image. Injecting xfs_metadir_create() reproduced the old active-update path
that left mount stuck later in mount setup; after this change, the same
injection reported cancel_hits=1 and irele_hits=1. Injecting
xfs_metadir_commit() exercised the old inode-reference leak path; after
this change, it reported irele_hits=1.

Fixes: e80fbe1ad8ef ("xfs: use metadir for quota inodes")
Cc: stable@vger.kernel.org # v6.13
Signed-off-by: Dawei Feng <dawei.feng@seu.edu.cn>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>