Messages in this thread Patch in this message | | | Subject | [PATCH 21/22] honor r/w changes at do_remount() time | From | Dave Hansen <> | Date | Fri, 09 Feb 2007 14:53:44 -0800 |
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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: _ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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