[ RFC ] xfs: 4K inode support

[Wang Yugui <wangyugui@e16-tech.com>]

use case for 4K inode
- simpler logic for 4Kn device, and less lock.
- better performance for directory with many files.
- maybe inline data support later.

TODO:
still crash in xfs_trans_read_buf_map() when mount a 4K inode xfs now.

---
 fs/xfs/libxfs/xfs_format.h   | 2 +-
 fs/xfs/libxfs/xfs_metafile.c | 2 +-
 fs/xfs/libxfs/xfs_sb.c       | 1 +
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index 779dac59b1f3..84cce8d268e6 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -1079,7 +1079,7 @@ enum xfs_dinode_fmt {
  * Inode minimum and maximum sizes.
  */
 #define	XFS_DINODE_MIN_LOG	8
-#define	XFS_DINODE_MAX_LOG	11
+#define	XFS_DINODE_MAX_LOG	12
 #define	XFS_DINODE_MIN_SIZE	(1 << XFS_DINODE_MIN_LOG)
 #define	XFS_DINODE_MAX_SIZE	(1 << XFS_DINODE_MAX_LOG)
 
diff --git a/fs/xfs/libxfs/xfs_metafile.c b/fs/xfs/libxfs/xfs_metafile.c
index cf239f862212..9db799576775 100644
--- a/fs/xfs/libxfs/xfs_metafile.c
+++ b/fs/xfs/libxfs/xfs_metafile.c
@@ -98,7 +98,7 @@ xfs_metafile_resv_can_cover(
 	 * isn't critical unless there also isn't enough free space.
 	 */
 	return xfs_compare_freecounter(mp, XC_FREE_BLOCKS,
-			rhs - mp->m_metafile_resv_avail, 2048) >= 0;
+			rhs - mp->m_metafile_resv_avail, 4096) >= 0;
 }
 
 /*
diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
index 38d16fe1f6d8..39424a7c74df 100644
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -734,6 +734,7 @@ xfs_validate_sb_common(
 	case 512:
 	case 1024:
 	case 2048:
+	case 4096:
 		break;
 	default:
 		xfs_warn(mp, "inode size of %d bytes not supported",
-- 
2.36.2