diff options
| author | Liu Bo <liubo2009@cn.fujitsu.com> | 2012-06-29 03:58:49 -0600 |
|---|---|---|
| committer | Chris Mason <chris.mason@fusionio.com> | 2012-07-23 16:27:58 -0400 |
| commit | b9ca0664dc806ba70587f6f3202b60dc736cd6e5 (patch) | |
| tree | fd40828d3af0ba3b16e1e9231c406d6a6b1bace4 /fs/btrfs | |
| parent | e54bfa31044d602a57d4e190f6d1c3763ea76bfe (diff) | |
Btrfs: do not set subvolume flags in readonly mode
$ mkfs.btrfs /dev/sdb7
$ btrfstune -S1 /dev/sdb7
$ mount /dev/sdb7 /mnt/btrfs
mount: block device /dev/sdb7 is write-protected, mounting read-only
$ btrfs dev add /dev/sdb8 /mnt/btrfs/
Now we get a btrfs in which mnt flags has readonly but sb flags does
not. So for those ioctls that only check sb flags with MS_RDONLY, it
is going to be a problem.
Setting subvolume flags is such an ioctl, we should use mnt_want_write_file()
to check RO flags.
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/ioctl.c | 42 |
1 files changed, 28 insertions, 14 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 13ed1c9534c..17facea6a51 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -1521,29 +1521,40 @@ static noinline int btrfs_ioctl_subvol_setflags(struct file *file, u64 flags; int ret = 0; - if (root->fs_info->sb->s_flags & MS_RDONLY) - return -EROFS; + ret = mnt_want_write_file(file); + if (ret) + goto out; - if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID) - return -EINVAL; + if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID) { + ret = -EINVAL; + goto out_drop_write; + } - if (copy_from_user(&flags, arg, sizeof(flags))) - return -EFAULT; + if (copy_from_user(&flags, arg, sizeof(flags))) { + ret = -EFAULT; + goto out_drop_write; + } - if (flags & BTRFS_SUBVOL_CREATE_ASYNC) - return -EINVAL; + if (flags & BTRFS_SUBVOL_CREATE_ASYNC) { + ret = -EINVAL; + goto out_drop_write; + } - if (flags & ~BTRFS_SUBVOL_RDONLY) - return -EOPNOTSUPP; + if (flags & ~BTRFS_SUBVOL_RDONLY) { + ret = -EOPNOTSUPP; + goto out_drop_write; + } - if (!inode_owner_or_capable(inode)) - return -EACCES; + if (!inode_owner_or_capable(inode)) { + ret = -EACCES; + goto out_drop_write; + } down_write(&root->fs_info->subvol_sem); /* nothing to do */ if (!!(flags & BTRFS_SUBVOL_RDONLY) == btrfs_root_readonly(root)) - goto out; + goto out_drop_sem; root_flags = btrfs_root_flags(&root->root_item); if (flags & BTRFS_SUBVOL_RDONLY) @@ -1566,8 +1577,11 @@ static noinline int btrfs_ioctl_subvol_setflags(struct file *file, out_reset: if (ret) btrfs_set_root_flags(&root->root_item, root_flags); -out: +out_drop_sem: up_write(&root->fs_info->subvol_sem); +out_drop_write: + mnt_drop_write_file(file); +out: return ret; } |