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 <[email protected]> >> --- >> 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. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
