[PATCH] Add preallocation beyond EOF to fallocate

David Chinner
2007-04-30T03:15:14Z

Add new mode to ->fallocate() to allow allocation to occur
beyond the current EOF without changing the file size. Implement
in XFS ->fallocate() vector.

Signed-Off-By: Dave Chinner <dgc@sgi.com>

---
fs/xfs/linux-2.6/xfs_iops.c | 8 +++++---
include/linux/fs.h | 1 +
2 files changed, 6 insertions(+), 3 deletions(-)

Index: 2.6.x-xfs-new/fs/xfs/linux-2.6/xfs_iops.c
===================================================================
--- 2.6.x-xfs-new.orig/fs/xfs/linux-2.6/xfs_iops.c 2007-04-30 11:02:16.000000000 +1000
+++ 2.6.x-xfs-new/fs/xfs/linux-2.6/xfs_iops.c 2007-04-30 11:09:48.233375382 +1000
@@ -833,11 +833,13 @@ xfs_vn_fallocate(
VNODE_POSITION_XFS);

switch (mode) {
- case FA_ALLOCATE: /* changes file size */
- error = xfs_change_file_space(bdp, XFS_IOC_RESVSP,
- &bf, 0, NULL, 0);
+ case FA_ALLOCATE: /* changes file size */
if (offset + len > i_size_read(inode))
do_setattr = offset + len;
+ /* FALL THROUGH */
+ case FA_PREALLOCATE: /* no filesize change */
+ error = xfs_change_file_space(bdp, XFS_IOC_RESVSP,
+ &bf, 0, NULL, 0);
break;
case FA_DEALLOCATE:
/* XXX: changes file size? this just punches a hole */
Index: 2.6.x-xfs-new/include/linux/fs.h
===================================================================
--- 2.6.x-xfs-new.orig/include/linux/fs.h 2007-04-27 18:48:01.000000000 +1000
+++ 2.6.x-xfs-new/include/linux/fs.h 2007-04-30 11:08:05.790903661 +1000
@@ -269,6 +269,7 @@ extern int dir_notify_enable;
*/
#define FA_ALLOCATE 0x1
#define FA_DEALLOCATE 0x2
+#define FA_PREALLOCATE 0x3

#ifdef __KERNEL__