The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=21ccdb4119afdfdfeaa80e9c8514171c65b35862
commit 21ccdb4119afdfdfeaa80e9c8514171c65b35862 Author: Konstantin Belousov <[email protected]> AuthorDate: 2024-05-15 09:54:49 +0000 Commit: Konstantin Belousov <[email protected]> CommitDate: 2024-05-16 01:00:26 +0000 vfs_domount_update(): postpone setting MNT_UNION until VFS_MOUNT() is done The file system that handles updating the mount point might do lookups during the update, in which case it could find the flag MNT_UNION set on the mp while mount point is still not updated. In particular, the rootvp->v_mount->mnt_vnodecovered is not yet set. Delay setting MNT_UNION until the mount is performed. PR: 265311 Reported by: Robert Morris <[email protected]> Reviewed by: mckusick, olce Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D45208 --- sys/kern/vfs_mount.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/sys/kern/vfs_mount.c b/sys/kern/vfs_mount.c index 4961eb332473..f5ff8d54fadd 100644 --- a/sys/kern/vfs_mount.c +++ b/sys/kern/vfs_mount.c @@ -1313,7 +1313,7 @@ vfs_domount_update( void *bufp; struct mount *mp; int error, export_error, i, len, fsid_up_len; - uint64_t flag; + uint64_t flag, mnt_union; gid_t *grps; fsid_t *fsid_up; bool vfs_suser_failed; @@ -1395,6 +1395,7 @@ vfs_domount_update( vfs_deleteopt(*optlist, "fsid"); } + mnt_union = 0; MNT_ILOCK(mp); if ((mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) { MNT_IUNLOCK(mp); @@ -1416,6 +1417,11 @@ vfs_domount_update( mp->mnt_flag |= MNT_UPDATE; } else { mp->mnt_flag &= ~MNT_UPDATEMASK; + if ((mp->mnt_flag & MNT_UNION) == 0 && + (fsflags & MNT_UNION) != 0) { + fsflags &= ~MNT_UNION; + mnt_union = MNT_UNION; + } mp->mnt_flag |= fsflags & (MNT_RELOAD | MNT_FORCE | MNT_UPDATE | MNT_SNAPSHOT | MNT_ROOTFS | MNT_UPDATEMASK | MNT_RDONLY); if ((mp->mnt_flag & MNT_ASYNC) == 0) @@ -1519,6 +1525,7 @@ vfs_domount_update( if (error == 0) { mp->mnt_flag &= ~(MNT_UPDATE | MNT_RELOAD | MNT_FORCE | MNT_SNAPSHOT); + mp->mnt_flag |= mnt_union; } else { /* * If we fail, restore old mount flags. MNT_QUOTA is special,
