Author: avg
Date: Wed Sep 15 11:05:41 2010
New Revision: 212657
URL: http://svn.freebsd.org/changeset/base/212657
Log:
zfs vn_has_cached_data: take into account v_object->cache != NULL
This mirrors code in tmpfs.
This changge shouldn't affect much read path, it may cause unnecessary
vm_page_lookup calls in the case where v_object has no active or inactive
pages but has some cache pages. I believe this situation to be non-essential.
In write path this change should allow us to properly detect the above
case and free a cache page when we write to a range that corresponds to it.
If this situation is undetected then we could have a discrepancy between
data in page cache and in ARC or on disk.
This change allows us to re-enable vn_has_cached_data() check in zfs_write.
NOTE: strictly speaking resident_page_count and cache fields of v_object
should be exmined under VM_OBJECT_LOCK, but for this particular usage
we may get away with it.
Discussed with: alc, kib
Approved by: pjd
Tested with: tools/regression/fsx
MFC after: 3 weeks
Modified:
head/sys/cddl/compat/opensolaris/sys/vnode.h
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
Modified: head/sys/cddl/compat/opensolaris/sys/vnode.h
==============================================================================
--- head/sys/cddl/compat/opensolaris/sys/vnode.h Wed Sep 15 11:04:02
2010 (r212656)
+++ head/sys/cddl/compat/opensolaris/sys/vnode.h Wed Sep 15 11:05:41
2010 (r212657)
@@ -69,7 +69,9 @@ vn_is_readonly(vnode_t *vp)
#define vn_vfsunlock(vp) do { } while (0)
#define vn_ismntpt(vp) ((vp)->v_type == VDIR &&
(vp)->v_mountedhere != NULL)
#define vn_mountedvfs(vp) ((vp)->v_mountedhere)
-#define vn_has_cached_data(vp) ((vp)->v_object != NULL &&
(vp)->v_object->resident_page_count > 0)
+#define vn_has_cached_data(vp) \
+ ((vp)->v_object != NULL && ((vp)->v_object->resident_page_count > 0 \
+ || (vp)->v_object->cache != NULL))
#define vn_exists(vp) do { } while (0)
#define vn_invalid(vp) do { } while (0)
#define vn_renamepath(tdvp, svp, tnm, lentnm) do { } while (0)
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c Wed Sep
15 11:04:02 2010 (r212656)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c Wed Sep
15 11:05:41 2010 (r212657)
@@ -933,17 +933,7 @@ again:
uioskip(uio, tx_bytes);
}
- /*
- * XXXPJD: There are some cases (triggered by fsx) where
- * vn_has_cached_data(vp) returns false when it should
- * return true. This should be investigated.
- */
-#if 0
- if (tx_bytes && vn_has_cached_data(vp))
-#else
- if (tx_bytes && vp->v_object != NULL)
-#endif
- {
+ if (tx_bytes && vn_has_cached_data(vp)) {
update_pages(vp, woff, tx_bytes, zfsvfs->z_os,
zp->z_id, uio->uio_segflg, tx);
}
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