The patch titled
r/o bind mounts: honor r/w changes at do_remount() time
has been removed from the -mm tree. Its filename was
r-o-bind-mounts-honor-r-w-changes-at-do_remount-time.patch
This patch was dropped because an updated version will be merged
------------------------------------------------------
Subject: r/o bind mounts: honor r/w changes at do_remount() time
From: Dave Hansen <hansendc@xxxxxxxxxx>
Originally from: Herbert Poetzl <herbert@xxxxxxxxxxxx>
This is the core of the read-only bind mount patch set.
Note that this does _not_ add a "ro" option directly to the bind mount
operation. If you require such a mount, you must first do the bind, then
follow it up with a 'mount -o remount,ro' operation.
Signed-off-by: Dave Hansen <haveblue@xxxxxxxxxx>
Cc: Miklos Szeredi <miklos@xxxxxxxxxx>
Cc: Ram Pai <linuxram@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/namespace.c | 24 ++++++++++++++++++++++--
fs/open.c | 2 +-
2 files changed, 23 insertions(+), 3 deletions(-)
diff -puN fs/namespace.c~r-o-bind-mounts-honor-r-w-changes-at-do_remount-time fs/namespace.c
--- a/fs/namespace.c~r-o-bind-mounts-honor-r-w-changes-at-do_remount-time
+++ a/fs/namespace.c
@@ -428,7 +428,7 @@ static int show_vfsmnt(struct seq_file *
seq_path(m, mnt, mnt->mnt_root, " \t\n\\");
seq_putc(m, ' ');
mangle(m, mnt->mnt_sb->s_type->name);
- seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? " ro" : " rw");
+ seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
for (fs_infop = fs_info; fs_infop->flag; fs_infop++) {
if (mnt->mnt_sb->s_flags & fs_infop->flag)
seq_puts(m, fs_infop->str);
@@ -997,6 +997,23 @@ out:
return err;
}
+static int change_mount_flags(struct vfsmount *mnt, int ms_flags)
+{
+ int error = 0;
+ int readonly_request = 0;
+
+ if (ms_flags & MS_RDONLY)
+ readonly_request = 1;
+ if (readonly_request == __mnt_is_readonly(mnt))
+ return 0;
+
+ if (readonly_request)
+ error = mnt_make_readonly(mnt);
+ else
+ __mnt_unmake_readonly(mnt);
+ return error;
+}
+
/*
* change filesystem flags. dir should be a physical root of filesystem.
* If you've mounted a non-root directory somewhere and want to do remount
@@ -1018,7 +1035,10 @@ static int do_remount(struct nameidata *
return -EINVAL;
down_write(&sb->s_umount);
- err = do_remount_sb(sb, flags, data, 0);
+ if (flags & MS_BIND)
+ err = change_mount_flags(nd->mnt, flags);
+ else
+ err = do_remount_sb(sb, flags, data, 0);
if (!err)
nd->mnt->mnt_flags = mnt_flags;
up_write(&sb->s_umount);
diff -puN fs/open.c~r-o-bind-mounts-honor-r-w-changes-at-do_remount-time fs/open.c
--- a/fs/open.c~r-o-bind-mounts-honor-r-w-changes-at-do_remount-time
+++ a/fs/open.c
@@ -401,7 +401,7 @@ asmlinkage long sys_faccessat(int dfd, c
special_file(nd.dentry->d_inode->i_mode))
goto out_path_release;
- if(IS_RDONLY(nd.dentry->d_inode))
+ if(__mnt_is_readonly(nd.mnt) || IS_RDONLY(nd.dentry->d_inode))
res = -EROFS;
out_path_release:
_
Patches currently in -mm which might be from hansendc@xxxxxxxxxx are
r-o-bind-mounts-honor-r-w-changes-at-do_remount-time.patch
r-o-bind-mounts-kill-open-files-traverse-on-remount-ro.patch
-
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