From: Dave Hansen <hansendc@us.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: akpm@osdl.org, hch@infradead.org, Dave Hansen <hansendc@us.ibm.com>
Subject: [PATCH 21/22] honor r/w changes at do_remount() time
Date: Fri, 09 Feb 2007 14:53:44 -0800 [thread overview]
Message-ID: <20070209225344.93A75D35@localhost.localdomain> (raw)
In-Reply-To: <20070209225329.27619A62@localhost.localdomain>
Originally from: Herbert Poetzl <herbert@13thfloor.at>
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@us.ibm.com>
---
lxc-dave/fs/namespace.c | 24 ++++++++++++++++++++++--
lxc-dave/fs/open.c | 2 +-
2 files changed, 23 insertions(+), 3 deletions(-)
diff -puN fs/namespace.c~23-24-honor-r-w-changes-at-do-remount-time fs/namespace.c
--- lxc/fs/namespace.c~23-24-honor-r-w-changes-at-do-remount-time 2007-02-09 14:27:00.000000000 -0800
+++ lxc-dave/fs/namespace.c 2007-02-09 14:27:00.000000000 -0800
@@ -443,7 +443,7 @@ 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);
@@ -1017,6 +1017,23 @@ 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
@@ -1038,7 +1055,10 @@ 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~23-24-honor-r-w-changes-at-do-remount-time fs/open.c
--- lxc/fs/open.c~23-24-honor-r-w-changes-at-do-remount-time 2007-02-09 14:27:00.000000000 -0800
+++ lxc-dave/fs/open.c 2007-02-09 14:27:00.000000000 -0800
@@ -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:
_
next prev parent reply other threads:[~2007-02-09 22:54 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-09 22:53 [PATCH 01/22] filesystem helpers for custom 'struct file's Dave Hansen
2007-02-09 22:53 ` [PATCH 02/22] r/o bind mounts: add vfsmount writer counts Dave Hansen
2007-02-09 23:41 ` Eric Dumazet
2007-02-10 0:10 ` Dave Hansen
2007-02-09 22:53 ` [PATCH 03/22] record when sb_writer_count elevated for inode Dave Hansen
2007-02-09 22:53 ` [PATCH 04/22] elevate writer count for chown and friends Dave Hansen
2007-02-09 22:53 ` [PATCH 05/22] elevate mnt writers for callers of vfs_mkdir() Dave Hansen
2007-02-09 22:53 ` [PATCH 06/22] elevate write count during entire ncp_ioctl() Dave Hansen
2007-02-09 22:53 ` [PATCH 08/22] elevate mount count for extended attributes Dave Hansen
2007-02-09 22:53 ` [PATCH 07/22] elevate write count for link and symlink calls Dave Hansen
2007-02-09 22:53 ` [PATCH 09/22] mount_is_safe(): add comment Dave Hansen
2007-02-09 22:53 ` [PATCH 10/22] unix_find_other() elevate write count for touch_atime() Dave Hansen
2007-02-09 22:53 ` [PATCH 11/22] elevate write count over calls to vfs_rename() Dave Hansen
2007-02-09 22:53 ` [PATCH 12/22] elevate write count files are open()ed Dave Hansen
2007-02-13 5:11 ` Andrew Morton
2007-02-13 16:58 ` Dave Hansen
2007-02-13 17:58 ` Andrew Morton
2007-02-14 0:17 ` Dave Hansen
2007-02-09 22:53 ` [PATCH 13/22] elevate writer count for do_sys_truncate() Dave Hansen
2007-02-09 22:53 ` [PATCH 14/22] elevate write count for do_utimes() Dave Hansen
2007-02-09 22:53 ` [PATCH 16/22] sys_mknodat(): elevate write count for vfs_mknod/create() Dave Hansen
2007-02-09 22:53 ` [PATCH 15/22] elevate write count for do_sys_utime() and touch_atime() Dave Hansen
2007-02-09 22:53 ` [PATCH 17/22] elevate mnt writers for vfs_unlink() callers Dave Hansen
2007-02-09 22:53 ` [PATCH 18/22] do_rmdir(): elevate write count Dave Hansen
2007-02-09 22:53 ` [PATCH 20/22] [PATCH] gfs: check nlink count Dave Hansen
2007-02-09 22:53 ` [PATCH 19/22] elevate writer count for custom struct_file Dave Hansen
2007-02-09 22:53 ` Dave Hansen [this message]
2007-02-09 23:22 ` [PATCH 21/22] honor r/w changes at do_remount() time Andrew Morton
2007-02-10 0:00 ` Dave Hansen
2007-02-10 0:29 ` Anton Altaparmakov
2007-02-10 9:54 ` Jan Engelhardt
2007-02-09 22:53 ` [PATCH 22/22] kill open files traverse on remount ro Dave Hansen
2007-02-09 23:18 ` [PATCH 01/22] filesystem helpers for custom 'struct file's Andrew Morton
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