From: Brian Foster <bfoster@redhat.com>
Date: Mon, 8 Jan 2018 10:41:38 -0800
Subject: xfs: eliminate duplicate icreate tx reservation functions
Git-commit: c017cb5ddfd6326032570d5eba83308c8a9c13a9
Patch-mainline: v4.16-rc1
References: bsc#1145235

The create transaction reservation calculation has two different
branches of code depending on whether the filesystem is a v5 format
fs or older. Each branch considers the max reservation between the
allocation case (new chunk allocation + record insert) and the
modify case (chunk exists, record modification) of inode allocation.

The modify case is the same for both superblock versions with the
exception of the finobt. The finobt helper checks the feature bit,
however, and so the modify case already shares the same code.

Now that inode chunk allocation has been refactored into a helper
that checks the superblock version to calculate the appropriate
reservation for the create transaction, the only remaining
difference between the create and icreate branches is the call to
the finobt helper. As noted above, the finobt helper is a no-op when
the feature is not enabled. Therefore, these branches are
effectively duplicate and can be condensed.

Remove the xfs_calc_create_*() branch of functions and update the
various callers to use the xfs_calc_icreate_*() variant. The latter
creates the same reservation size for v4 create transactions as the
removed branch. As such, this patch does not result in transaction
reservation changes.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/xfs/libxfs/xfs_trans_resv.c | 52 +++++-------------------------------------
 1 file changed, 6 insertions(+), 46 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c
index 75259a1346eb..5f17641f040f 100644
--- a/fs/xfs/libxfs/xfs_trans_resv.c
+++ b/fs/xfs/libxfs/xfs_trans_resv.c
@@ -413,39 +413,13 @@ xfs_calc_create_resv_modify(
 		xfs_calc_finobt_res(mp);
 }
 
-/*
- * For create we can allocate some inodes giving:
- *    the agi and agf of the ag getting the new inodes: 2 * sectorsize
- *    the superblock for the nlink flag: sector size
- *    the inode chunk (allocation/init)
- *    the inode btree (record insertion)
- */
-STATIC uint
-xfs_calc_create_resv_alloc(
-	struct xfs_mount	*mp)
-{
-	return xfs_calc_buf_res(2, mp->m_sb.sb_sectsize) +
-		mp->m_sb.sb_sectsize +
-		xfs_calc_inode_chunk_res(mp, _ALLOC) +
-		xfs_calc_inobt_res(mp);
-}
-
-STATIC uint
-__xfs_calc_create_reservation(
-	struct xfs_mount	*mp)
-{
-	return XFS_DQUOT_LOGRES(mp) +
-		MAX(xfs_calc_create_resv_alloc(mp),
-		    xfs_calc_create_resv_modify(mp));
-}
-
 /*
  * For icreate we can allocate some inodes giving:
  *    the agi and agf of the ag getting the new inodes: 2 * sectorsize
  *    the superblock for the nlink flag: sector size
- *    the inode chunk (allocation, no init)
+ *    the inode chunk (allocation, optional init)
  *    the inobt (record insertion)
- *    the finobt (record insertion)
+ *    the finobt (optional, record insertion)
  */
 STATIC uint
 xfs_calc_icreate_resv_alloc(
@@ -466,27 +440,13 @@ xfs_calc_icreate_reservation(xfs_mount_t *mp)
 		    xfs_calc_create_resv_modify(mp));
 }
 
-STATIC uint
-xfs_calc_create_reservation(
-	struct xfs_mount	*mp)
-{
-	if (xfs_sb_version_hascrc(&mp->m_sb))
-		return xfs_calc_icreate_reservation(mp);
-	return __xfs_calc_create_reservation(mp);
-
-}
-
 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);
-
+	res += xfs_calc_icreate_resv_alloc(mp);
 	return res + xfs_calc_iunlink_add_reservation(mp);
 }
 
@@ -497,7 +457,7 @@ STATIC uint
 xfs_calc_mkdir_reservation(
 	struct xfs_mount	*mp)
 {
-	return xfs_calc_create_reservation(mp);
+	return xfs_calc_icreate_reservation(mp);
 }
 
 
@@ -510,7 +470,7 @@ STATIC uint
 xfs_calc_symlink_reservation(
 	struct xfs_mount	*mp)
 {
-	return xfs_calc_create_reservation(mp) +
+	return xfs_calc_icreate_reservation(mp) +
 	       xfs_calc_buf_res(1, XFS_SYMLINK_MAXLEN);
 }
 
@@ -869,7 +829,7 @@ xfs_trans_resv_calc(
 	resp->tr_symlink.tr_logcount = XFS_SYMLINK_LOG_COUNT;
 	resp->tr_symlink.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
 
-	resp->tr_create.tr_logres = xfs_calc_create_reservation(mp);
+	resp->tr_create.tr_logres = xfs_calc_icreate_reservation(mp);
 	resp->tr_create.tr_logcount = XFS_CREATE_LOG_COUNT;
 	resp->tr_create.tr_logflags |= XFS_TRANS_PERM_LOG_RES;