xfs: add O_TMPFILE support

Add two functions xfs_create_tmpfile() and xfs_vn_tmpfile()
to support O_TMPFILE file creation.

In contrast to xfs_create(), xfs_create_tmpfile() has a different
log reservation to the regular file creation because there is no
directory modification, and doesn't check if an entry can be added
to the directory, but the reservation quotas is required appropriately,
and finally its inode is added to the unlinked list.

xfs_vn_tmpfile() add one O_TMPFILE method to VFS interface and directly
invoke xfs_create_tmpfile().

Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 107 insertions, 0 deletions

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index c79b875..ac133ea 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1333,6 +1333,113 @@ xfs_create(
 }
 
 int
+xfs_create_tmpfile(
+	struct xfs_inode	*dp,
+	struct dentry		*dentry,
+	umode_t			mode)
+{
+	struct xfs_mount	*mp = dp->i_mount;
+	struct xfs_inode	*ip = NULL;
+	struct xfs_trans	*tp = NULL;
+	int			error;
+	uint			cancel_flags = XFS_TRANS_RELEASE_LOG_RES;
+	prid_t                  prid;
+	struct xfs_dquot	*udqp = NULL;
+	struct xfs_dquot	*gdqp = NULL;
+	struct xfs_dquot	*pdqp = NULL;
+	struct xfs_trans_res	*tres;
+	uint			resblks;
+
+	if (XFS_FORCED_SHUTDOWN(mp))
+		return XFS_ERROR(EIO);
+
+	prid = xfs_get_initial_prid(dp);
+
+	/*
+	 * Make sure that we have allocated dquot(s) on disk.
+	 */
+	error = xfs_qm_vop_dqalloc(dp, xfs_kuid_to_uid(current_fsuid()),
+				xfs_kgid_to_gid(current_fsgid()), prid,
+				XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT,
+				&udqp, &gdqp, &pdqp);
+	if (error)
+		return error;
+
+	resblks = XFS_IALLOC_SPACE_RES(mp);
+	tp = xfs_trans_alloc(mp, XFS_TRANS_CREATE_TMPFILE);
+
+	tres = &M_RES(mp)->tr_create_tmpfile;
+	error = xfs_trans_reserve(tp, tres, resblks, 0);
+	if (error == ENOSPC) {
+		/* No space at all so try a "no-allocation" reservation */
+		resblks = 0;
+		error = xfs_trans_reserve(tp, tres, 0, 0);
+	}
+	if (error) {
+		cancel_flags = 0;
+		goto out_trans_cancel;
+	}
+
+	error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp,
+						pdqp, resblks, 1, 0);
+	if (error)
+		goto out_trans_cancel;
+
+	error = xfs_dir_ialloc(&tp, dp, mode, 1, 0,
+				prid, resblks > 0, &ip, NULL);
+	if (error) {
+		if (error == ENOSPC)
+			goto out_trans_cancel;
+		goto out_trans_abort;
+	}
+
+	if (mp->m_flags & XFS_MOUNT_WSYNC)
+		xfs_trans_set_sync(tp);
+
+	/*
+	 * Attach the dquot(s) to the inodes and modify them incore.
+	 * These ids of the inode couldn't have changed since the new
+	 * inode has been locked ever since it was created.
+	 */
+	xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
+
+	ip->i_d.di_nlink--;
+	d_tmpfile(dentry, VFS_I(ip));
+	error = xfs_iunlink(tp, ip);
+	if (error)
+		goto out_trans_abort;
+
+	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
+	if (error)
+		goto out_release_inode;
+
+	xfs_qm_dqrele(udqp);
+	xfs_qm_dqrele(gdqp);
+	xfs_qm_dqrele(pdqp);
+
+	return 0;
+
+ out_trans_abort:
+	cancel_flags |= XFS_TRANS_ABORT;
+ out_trans_cancel:
+	xfs_trans_cancel(tp, cancel_flags);
+ out_release_inode:
+	/*
+	 * Wait until after the current transaction is aborted to
+	 * release the inode.  This prevents recursive transactions
+	 * and deadlocks from xfs_inactive.
+	 */
+	if (ip)
+		IRELE(ip);
+
+	xfs_qm_dqrele(udqp);
+	xfs_qm_dqrele(gdqp);
+	xfs_qm_dqrele(pdqp);
+
+	return error;
+}
+
+int
 xfs_link(
 	xfs_inode_t		*tdp,
 	xfs_inode_t		*sip,