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, 34 insertions, 2 deletions

diff --git a/fs/xfs/xfs_trans_resv.c b/fs/xfs/xfs_trans_resv.c
index 2fd59c0dae66..bd3b4b7831b7 100644
--- a/fs/xfs/xfs_trans_resv.c
+++ b/fs/xfs/xfs_trans_resv.c
@@ -229,6 +229,18 @@ xfs_calc_link_reservation(
 }
 
 /*
+ * For adding an inode to unlinked list we can modify:
+ *    the agi hash list: sector size
+ *    the unlinked inode: inode size
+ */
+STATIC uint
+xfs_calc_iunlink_add_reservation(xfs_mount_t *mp)
+{
+	return xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) +
+		xfs_calc_inode_res(mp, 1);
+}
+
+/*
  * For removing a directory entry we can modify:
  *    the parent directory inode: inode size
  *    the removed inode: inode size
@@ -245,10 +257,11 @@ xfs_calc_remove_reservation(
 	struct xfs_mount	*mp)
 {
 	return XFS_DQUOT_LOGRES(mp) +
-		MAX((xfs_calc_inode_res(mp, 2) +
+		xfs_calc_iunlink_add_reservation(mp) +
+		MAX((xfs_calc_inode_res(mp, 1) +
 		     xfs_calc_buf_res(XFS_DIROP_LOG_COUNT(mp),
 				      XFS_FSB_TO_B(mp, 1))),
-		    (xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) +
+		    (xfs_calc_buf_res(4, mp->m_sb.sb_sectsize) +
 		     xfs_calc_buf_res(XFS_ALLOCFREE_LOG_COUNT(mp, 2),
 				      XFS_FSB_TO_B(mp, 1))));
 }
@@ -343,6 +356,20 @@ xfs_calc_create_reservation(
 
 }
 
+STATIC uint
+xfs_calc_create_tmpfile_reservation(
+	struct xfs_mount        *mp)
+{
+	uint	res = XFS_DQUOT_LOGRES(mp);
+
+	if (xfs_sb_version_hascrc(&mp->m_sb))
+		res += xfs_calc_icreate_resv_alloc(mp);
+	else
+		res += xfs_calc_create_resv_alloc(mp);
+
+	return res + xfs_calc_iunlink_add_reservation(mp);
+}
+
 /*
  * Making a new directory is the same as creating a new file.
  */
@@ -729,6 +756,11 @@ xfs_trans_resv_calc(
 	resp->tr_create.tr_logcount = XFS_CREATE_LOG_COUNT;
 	resp->tr_create.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
 
+	resp->tr_create_tmpfile.tr_logres =
+			xfs_calc_create_tmpfile_reservation(mp);
+	resp->tr_create_tmpfile.tr_logcount = XFS_CREATE_TMPFILE_LOG_COUNT;
+	resp->tr_create_tmpfile.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
+
 	resp->tr_mkdir.tr_logres = xfs_calc_mkdir_reservation(mp);
 	resp->tr_mkdir.tr_logcount = XFS_MKDIR_LOG_COUNT;
 	resp->tr_mkdir.tr_logflags |= XFS_TRANS_PERM_LOG_RES;