mirror/freebsd
1
0
Fork 0
mirror of https://git.FreeBSD.org/src.git synced 2024-12-20 11:11:24 +00:00
Code Issues Releases Activity

zfs vn_has_cached_data: take into account v_object->cache != NULL

Browse Source 
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
This commit is contained in:
Andriy Gapon 2010-09-15 11:05:41 +00:00
parent 0b1ca38a69
commit 8a3883cfb7
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=212657
2 changed files with 4 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
sys/cddl/compat/opensolaris/sys/vnode.h
View File

@ -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)

12
sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
View File

@ -933,17 +933,7 @@ zfs_write(vnode_t *vp, uio_t *uio, int ioflag, cred_t *cr, caller_context_t *ct)
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);
}