[RESEND v3 PATCH 3/3] vfs: make mounts and mountstats honor root dir like mountinfo does

[Dmitry V. Levin]

Date: Wed, 17 Oct 2012 20:29:55 +0400

Change show_vfsmnt() and show_vfsstat() to show mountpoints relative
to the root directory and skip mountpoints outside of chroot jail
the same way as show_mountinfo() does.

Signed-off-by: Dmitry V. Levin <l...@altlinux.org>
---
 fs/proc_namespace.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
index 789e8d1..0f96f71 100644
--- a/fs/proc_namespace.c
+++ b/fs/proc_namespace.c
@@ -91,6 +91,7 @@ static void show_type(struct seq_file *m, struct super_block 
*sb)
 
 static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt)
 {
+       struct proc_mounts *p = proc_mounts(m);
        struct mount *r = real_mount(mnt);
        int err = 0;
        struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
@@ -104,7 +105,10 @@ static int show_vfsmnt(struct seq_file *m, struct vfsmount 
*mnt)
                mangle(m, r->mnt_devname ? r->mnt_devname : "none");
        }
        seq_putc(m, ' ');
-       seq_path(m, &mnt_path, " \t\n\\");
+       /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
+       err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
+       if (err)
+               goto out;
        seq_putc(m, ' ');
        show_type(m, sb);
        seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
@@ -181,6 +185,7 @@ out:
 
 static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
 {
+       struct proc_mounts *p = proc_mounts(m);
        struct mount *r = real_mount(mnt);
        struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
        struct super_block *sb = mnt_path.dentry->d_sb;
@@ -200,7 +205,10 @@ static int show_vfsstat(struct seq_file *m, struct 
vfsmount *mnt)
 
        /* mount point */
        seq_puts(m, " mounted on ");
-       seq_path(m, &mnt_path, " \t\n\\");
+       /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
+       err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
+       if (err)
+               goto out;
        seq_putc(m, ' ');
 
        /* file system type */
@@ -215,6 +223,7 @@ static int show_vfsstat(struct seq_file *m, struct vfsmount 
*mnt)
        }
 
        seq_putc(m, '\n');
+out:
        return err;
 }
 
-- 
ldv

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