git: 503f72a828c7 - main - ncl_bioread(): check for vp->v_object before accessing it

[Konstantin Belousov]

The branch main has been updated by kib:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=503f72a828c7d0d938ec73ffbf62406038c69d47

commit 503f72a828c7d0d938ec73ffbf62406038c69d47
Author:     Konstantin Belousov <k...@freebsd.org>
AuthorDate: 2024-01-15 11:49:14 +0000
Commit:     Konstantin Belousov <k...@freebsd.org>
CommitDate: 2024-01-15 15:19:58 +0000

    ncl_bioread(): check for vp->v_object before accessing it
    
    Reported by:    cy
    Reviewed by:    rmacklem
    Fixes:  70dc6b2ce314a0f32755005ad02802fca7ed186e
    MFC after:      3 days
---
 sys/fs/nfsclient/nfs_clbio.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/sys/fs/nfsclient/nfs_clbio.c b/sys/fs/nfsclient/nfs_clbio.c
index c027d7d7c3fd..1cf45bb0c924 100644
--- a/sys/fs/nfsclient/nfs_clbio.c
+++ b/sys/fs/nfsclient/nfs_clbio.c
@@ -414,6 +414,18 @@ out:
        return (error);
 }
 
+static bool
+ncl_bioread_dora(struct vnode *vp)
+{
+       vm_object_t obj;
+
+       obj = vp->v_object;
+       if (obj == NULL)
+               return (true);
+       return (!vm_object_mightbedirty(vp->v_object) &&
+           vp->v_object->un_pager.vnp.writemappings == 0);
+}
+
 /*
  * Vnode op for read using bio
  */
@@ -486,9 +498,7 @@ ncl_bioread(struct vnode *vp, struct uio *uio, int ioflag, 
struct ucred *cred)
                 * unlocked read by nfsiod could obliterate changes
                 * done by userspace.
                 */
-               if (nmp->nm_readahead > 0 &&
-                   !vm_object_mightbedirty(vp->v_object) &&
-                   vp->v_object->un_pager.vnp.writemappings == 0) {
+               if (nmp->nm_readahead > 0 && ncl_bioread_dora(vp)) {
                    for (nra = 0; nra < nmp->nm_readahead && nra < seqcount &&
                        (off_t)(lbn + 1 + nra) * biosize < nsize; nra++) {
                        rabn = lbn + 1 + nra;
@@ -675,9 +685,7 @@ ncl_bioread(struct vnode *vp, struct uio *uio, int ioflag, 
struct ucred *cred)
                 *  directory offset cookie of the next block.)
                 */
                NFSLOCKNODE(np);
-               if (nmp->nm_readahead > 0 &&
-                   !vm_object_mightbedirty(vp->v_object) &&
-                   vp->v_object->un_pager.vnp.writemappings == 0 &&
+               if (nmp->nm_readahead > 0 && ncl_bioread_dora(vp) &&
                    (bp->b_flags & B_INVAL) == 0 &&
                    (np->n_direofoffset == 0 ||
                    (lbn + 1) * NFS_DIRBLKSIZ < np->n_direofoffset) &&