On 01/09/2015 11:40 AM, hujianyang wrote:
> On 2015/1/8 20:41, Seunghun Lee wrote:
>> When file system is mounted read-only workdir is not needed.
>>
>> Signed-off-by: Seunghun Lee <waydi1@xxxxxxxxx>
>> ---
>> fs/overlayfs/super.c | 35 +++++++++++++++++++++++------------
>> 1 file changed, 23 insertions(+), 12 deletions(-)
>>
>> diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
>> index 84f3144..4e50617 100644
>> --- a/fs/overlayfs/super.c
>> +++ b/fs/overlayfs/super.c
>> @@ -30,6 +30,7 @@ struct ovl_config {
>> char *lowerdir;
>> char *upperdir;
>> char *workdir;
>> + bool is_rw;
>> };
>>
>> /* private information held for overlayfs's superblock */
>> @@ -515,10 +516,11 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
>> struct ovl_fs *ufs = sb->s_fs_info;
>>
>> seq_printf(m, ",lowerdir=%s", ufs->config.lowerdir);
>> - if (ufs->config.upperdir) {
>> + if (ufs->config.upperdir)
>> seq_printf(m, ",upperdir=%s", ufs->config.upperdir);
>> + if (ufs->config.is_rw)
>> seq_printf(m, ",workdir=%s", ufs->config.workdir);
>> - }
>> +
>> return 0;
>> }
>>
>> @@ -822,16 +824,27 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
>>
>> sb->s_stack_depth = 0;
>> if (ufs->config.upperdir) {
>> - /* FIXME: workdir is not needed for a R/O mount */
>> + err = ovl_mount_dir(ufs->config.upperdir, &upperpath);
>> + if (err)
>> + goto out_free_config;
>> +
>> + sb->s_stack_depth = upperpath.mnt->mnt_sb->s_stack_depth;
>> + }
>> +
>> + /* If the upper fs is r/o or nonexistent, we mark overlayfs r/o too */
>> + if (!upperpath.mnt || (upperpath.mnt->mnt_sb->s_flags & MS_RDONLY)) {
>> + ufs->config.is_rw = false;
>> + sb->s_flags |= MS_RDONLY;
>> + } else {
>> + ufs->config.is_rw = true;
>> + }
> Hi Seunghun,
>
> A partition can be mounted with ro flag. I think workdir is not
> needed in this way either.
Hi Hu,
I agree with you, workdir is not needed when filesystem is mounted with ro flag.
After mount, however, it can be remounted with rw flag.
Thanks.
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