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authorKonstantin Belousov <kib@FreeBSD.org>2024-01-01 22:22:44 +0000
committerKonstantin Belousov <kib@FreeBSD.org>2024-01-05 04:58:58 +0000
commit70dc6b2ce314a0f32755005ad02802fca7ed186e (patch)
tree7e01688b98f870f20be21fc74384251a95f42625 /sys
parent2d33ad48bd37f27925e4c46c798f8f2d23a2b501 (diff)
Diffstat (limited to 'sys')
-rw-r--r--sys/fs/nfsclient/nfs_clbio.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/sys/fs/nfsclient/nfs_clbio.c b/sys/fs/nfsclient/nfs_clbio.c
index e6486af55daf..f6506e34ee59 100644
--- a/sys/fs/nfsclient/nfs_clbio.c
+++ b/sys/fs/nfsclient/nfs_clbio.c
@@ -481,9 +481,14 @@ 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;
@@ -671,6 +676,8 @@ 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) &&