The branch stable/13 has been updated by kib:
URL:
https://cgit.FreeBSD.org/src/commit/?id=cc5cda1dbaa907ce52074f47264cc45b5a7d6c8b
commit cc5cda1dbaa907ce52074f47264cc45b5a7d6c8b
Author: Konstantin Belousov <k...@freebsd.org>
AuthorDate: 2024-01-01 22:22:44 +0000
Commit: Konstantin Belousov <k...@freebsd.org>
CommitDate: 2024-01-11 16:47:52 +0000
nfsclient: limit situations when we do unlocked read-ahead by nfsiod
(cherry picked from commit 70dc6b2ce314a0f32755005ad02802fca7ed186e)
---
sys/fs/nfsclient/nfs_clbio.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/sys/fs/nfsclient/nfs_clbio.c b/sys/fs/nfsclient/nfs_clbio.c
index 63e97f405198..7b9b68782d53 100644
--- a/sys/fs/nfsclient/nfs_clbio.c
+++ b/sys/fs/nfsclient/nfs_clbio.c
@@ -484,9 +484,14 @@ ncl_bioread(struct vnode *vp, struct uio *uio, int ioflag,
struct ucred *cred)
on = uio->uio_offset - (lbn * biosize);
/*
- * Start the read ahead(s), as required.
+ * Start the read ahead(s), as required. Do not do
+ * read-ahead if there are writeable mappings, since
+ * unlocked read by nfsiod could obliterate changes
+ * done by userspace.
*/
- if (nmp->nm_readahead > 0) {
+ if (nmp->nm_readahead > 0 &&
+ !vm_object_mightbedirty(vp->v_object) &&
+ vp->v_object->un_pager.vnp.writemappings == 0) {
for (nra = 0; nra < nmp->nm_readahead && nra < seqcount &&
(off_t)(lbn + 1 + nra) * biosize < nsize; nra++) {
rabn = lbn + 1 + nra;
@@ -674,6 +679,8 @@ ncl_bioread(struct vnode *vp, struct uio *uio, int ioflag,
struct ucred *cred)
*/
NFSLOCKNODE(np);
if (nmp->nm_readahead > 0 &&
+ !vm_object_mightbedirty(vp->v_object) &&
+ vp->v_object->un_pager.vnp.writemappings == 0 &&
(bp->b_flags & B_INVAL) == 0 &&
(np->n_direofoffset == 0 ||
(lbn + 1) * NFS_DIRBLKSIZ < np->n_direofoffset) &&
