By calling mount(2) with MS_REMOUNT | MS_BIND on a non-bind readonly
mountpoint, it is possible to have a readonly mount without MNT_READONLY
in its mnt_flags. Currently, /proc/<pid>/mountinfo will report such a
mount as r/w in the 4th column, even though for all intents and purposes
it is still readonly.
This patch makes show_mountinfo use __mnt_is_readonly to check if a
mount is readonly, which checks both for MNT_READONLY in mnt_flags and
for MS_RDONLY in mnt_sb->s_flags.
Signed-off-by: Shea Levy <shea@xxxxxxxxxxxx>
---
fs/proc_namespace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
index 5fe34c3..cf8963c 100644
--- a/fs/proc_namespace.c
+++ b/fs/proc_namespace.c
@@ -143,7 +143,7 @@ static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
if (err)
goto out;
- seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw");
+ seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
show_mnt_opts(m, mnt);
/* Tagged fields ("foo:X" or "bar") */
--
1.8.1.3
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