vfs: support FS_XFLAG_COWEXTSIZE and get/set of CoW extent size hint

Introduce XFLAGs for the new XFS CoW extent size hint, and actually
plumb the CoW extent size hint into the fsxattr structure.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 3 insertions, 1 deletions

diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 3b00f7c8943f..cf398764b19e 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -157,7 +157,8 @@ struct fsxattr {
         __u32           fsx_extsize;    /* extsize field value (get/set)*/
         __u32           fsx_nextents;   /* nextents field value (get)   */
         __u32           fsx_projid;     /* project identifier (get/set) */
-        unsigned char   fsx_pad[12];
+        __u32           fsx_cowextsize; /* CoW extsize field value (get/set)*/
+        unsigned char   fsx_pad[8];
 };
 
 /*
@@ -178,6 +179,7 @@ struct fsxattr {
 #define FS_XFLAG_NODEFRAG       0x00002000      /* do not defragment */
 #define FS_XFLAG_FILESTREAM     0x00004000      /* use filestream allocator */
 #define FS_XFLAG_DAX            0x00008000      /* use DAX for IO */
+#define FS_XFLAG_COWEXTSIZE     0x00010000      /* CoW extent size allocator hint */
 #define FS_XFLAG_HASATTR        0x80000000      /* no DIFLAG for this   */
 
 /* the read-only stuff doesn't really belong here, but any other place is