Did we ever discover what was behind the comment:
"Have to do this even if the file's size doesn't change"
Cheers
-- Mark
David Chinner wrote:
XFS changes the c/mtime of an inode when truncating it to the same
size. The c/mtime is only supposed to change if the size is changed.
Not to be confused with ftruncate, where the c/mtime is supposed to
be changed even if the size is not changed.
The Linux VFS encodes this semantic difference in the flags it sends
down to ->setattr, which XFS currently ignores. We need to make XFS
pay attention to the VFS flags and hence Do The Right Thing.
Signed-off-by: Dave Chinner <dgc@xxxxxxx>
---
fs/xfs/xfs_vnodeops.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
Index: 2.6.x-xfs-new/fs/xfs/xfs_vnodeops.c
===================================================================
--- 2.6.x-xfs-new.orig/fs/xfs/xfs_vnodeops.c 2008-01-25 16:03:23.654971763 +1100
+++ 2.6.x-xfs-new/fs/xfs/xfs_vnodeops.c 2008-01-25 16:10:30.875397129 +1100
@@ -634,6 +634,15 @@ xfs_setattr(
* Truncate file. Must have write permission and not be a directory.
*/
if (mask & XFS_AT_SIZE) {
+ /*
+ * Only change the c/mtime if we are changing the size
+ * or we are explicitly asked to change it. This handles
+ * the semantic difference between truncate() and ftruncate()
+ * as implemented in the VFS.
+ */
+ if (vap->va_size != ip->i_size || mask & XFS_AT_CTIME)
+ timeflags |= XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG;
+
if (vap->va_size > ip->i_size) {
xfs_igrow_finish(tp, ip, vap->va_size,
!(flags & ATTR_DMI));
@@ -662,10 +671,6 @@ xfs_setattr(
*/
xfs_iflags_set(ip, XFS_ITRUNCATED);
}
- /*
- * Have to do this even if the file's size doesn't change.
- */
- timeflags |= XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG;
}
/*
--
Mark Goodwin markgw@xxxxxxx
Engineering Manager for XFS and PCP Phone: +61-3-99631937
SGI Australian Software Group Cell: +61-4-18969583
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