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| author | Konstantin Belousov <kib@FreeBSD.org> | 2024-05-15 09:54:49 +0000 |
|---|---|---|
| committer | Konstantin Belousov <kib@FreeBSD.org> | 2024-05-16 01:00:26 +0000 |
| commit | 21ccdb4119afdfdfeaa80e9c8514171c65b35862 (patch) | |
| tree | d682b6986536f24751125084f9d9a0836732e43e | |
| parent | 5a061a38cdfa151315051a1ca1400bb32e39cde2 (diff) | |
| download | src-21ccdb4119afdfdfeaa80e9c8514171c65b35862.tar.gz src-21ccdb4119afdfdfeaa80e9c8514171c65b35862.zip | |
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 <rtm@lcs.mit.edu>
Reviewed by: mckusick, olce
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D45208
| -rw-r--r-- | sys/kern/vfs_mount.c | 9 |
1 files changed, 8 insertions, 1 deletions
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, |