diff options
Diffstat (limited to 'fs/namespace.c')
| -rw-r--r-- | fs/namespace.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index c3a80ffaf1e5..e6a7e769d25d 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -4026,8 +4026,9 @@ static int can_idmap_mount(const struct mount_kattr *kattr, struct mount *mnt) static inline bool mnt_allow_writers(const struct mount_kattr *kattr, const struct mount *mnt) { - return !(kattr->attr_set & MNT_READONLY) || - (mnt->mnt.mnt_flags & MNT_READONLY); + return (!(kattr->attr_set & MNT_READONLY) || + (mnt->mnt.mnt_flags & MNT_READONLY)) && + !kattr->mnt_userns; } static int mount_setattr_prepare(struct mount_kattr *kattr, struct mount *mnt) @@ -4058,10 +4059,22 @@ static int mount_setattr_prepare(struct mount_kattr *kattr, struct mount *mnt) if (err) { struct mount *p; - for (p = mnt; p != m; p = next_mnt(p, mnt)) { + /* + * If we had to call mnt_hold_writers() MNT_WRITE_HOLD will + * be set in @mnt_flags. The loop unsets MNT_WRITE_HOLD for all + * mounts and needs to take care to include the first mount. + */ + for (p = mnt; p; p = next_mnt(p, mnt)) { /* If we had to hold writers unblock them. */ if (p->mnt.mnt_flags & MNT_WRITE_HOLD) mnt_unhold_writers(p); + + /* + * We're done once the first mount we changed got + * MNT_WRITE_HOLD unset. + */ + if (p == m) + break; } } return err; |