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ovl: make upperdir optional 

Make "upperdir=" mount option optional.  If "upperdir=" is not given, then
the "workdir=" option is also optional (and ignored if given).

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
This commit is contained in:
Miklos Szeredi 2014-12-13 00:59:51 +01:00
parent ab508822ca
commit 53a08cb9b8
1 changed files with 47 additions and 36 deletions
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83
fs/overlayfs/super.c
View File

@ -516,8 +516,10 @@ 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);
seq_printf(m, ",upperdir=%s", ufs->config.upperdir);
seq_printf(m, ",workdir=%s", ufs->config.workdir);
if (ufs->config.upperdir) {
seq_printf(m, ",upperdir=%s", ufs->config.upperdir);
seq_printf(m, ",workdir=%s", ufs->config.workdir);
}
return 0;
}
@ -768,8 +770,8 @@ static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir)
static int ovl_fill_super(struct super_block *sb, void *data, int silent)
{
struct path lowerpath;
struct path upperpath;
struct path workpath;
struct path upperpath = { NULL, NULL };
struct path workpath = { NULL, NULL };
struct dentry *root_dentry;
struct ovl_entry *oe;
struct ovl_fs *ufs;
@ -786,31 +788,38 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
if (err)
goto out_free_config;
/* FIXME: workdir is not needed for a R/O mount */
err = -EINVAL;
if (!ufs->config.upperdir || !ufs->config.lowerdir ||
!ufs->config.workdir) {
pr_err("overlayfs: missing upperdir or lowerdir or workdir\n");
if (!ufs->config.lowerdir) {
pr_err("overlayfs: missing 'lowerdir'\n");
goto out_free_config;
}
err = ovl_mount_dir(ufs->config.upperdir, &upperpath);
if (err)
goto out_free_config;
sb->s_stack_depth = 0;
if (ufs->config.upperdir) {
/* FIXME: workdir is not needed for a R/O mount */
if (!ufs->config.workdir) {
pr_err("overlayfs: missing 'workdir'\n");
goto out_free_config;
}
err = ovl_mount_dir(ufs->config.workdir, &workpath);
if (err)
goto out_put_upperpath;
err = ovl_mount_dir(ufs->config.upperdir, &upperpath);
if (err)
goto out_free_config;
if (upperpath.mnt != workpath.mnt) {
pr_err("overlayfs: workdir and upperdir must reside under the same mount\n");
goto out_put_workpath;
err = ovl_mount_dir(ufs->config.workdir, &workpath);
if (err)
goto out_put_upperpath;
if (upperpath.mnt != workpath.mnt) {
pr_err("overlayfs: workdir and upperdir must reside under the same mount\n");
goto out_put_workpath;
}
if (!ovl_workdir_ok(workpath.dentry, upperpath.dentry)) {
pr_err("overlayfs: workdir and upperdir must be separate subtrees\n");
goto out_put_workpath;
}
sb->s_stack_depth = upperpath.mnt->mnt_sb->s_stack_depth;
}
if (!ovl_workdir_ok(workpath.dentry, upperpath.dentry)) {
pr_err("overlayfs: workdir and upperdir must be separate subtrees\n");
goto out_put_workpath;
}
sb->s_stack_depth = upperpath.mnt->mnt_sb->s_stack_depth;
err = ovl_lower_dir(ufs->config.lowerdir, &lowerpath,
&ufs->lower_namelen, &sb->s_stack_depth);
@ -824,19 +833,21 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
goto out_put_lowerpath;
}
ufs->upper_mnt = clone_private_mount(&upperpath);
err = PTR_ERR(ufs->upper_mnt);
if (IS_ERR(ufs->upper_mnt)) {
pr_err("overlayfs: failed to clone upperpath\n");
goto out_put_lowerpath;
}
if (ufs->config.upperdir) {
ufs->upper_mnt = clone_private_mount(&upperpath);
err = PTR_ERR(ufs->upper_mnt);
if (IS_ERR(ufs->upper_mnt)) {
pr_err("overlayfs: failed to clone upperpath\n");
goto out_put_lowerpath;
}
ufs->workdir = ovl_workdir_create(ufs->upper_mnt, workpath.dentry);
err = PTR_ERR(ufs->workdir);
if (IS_ERR(ufs->workdir)) {
pr_err("overlayfs: failed to create directory %s/%s\n",
ufs->config.workdir, OVL_WORKDIR_NAME);
goto out_put_upper_mnt;
ufs->workdir = ovl_workdir_create(ufs->upper_mnt, workpath.dentry);
err = PTR_ERR(ufs->workdir);
if (IS_ERR(ufs->workdir)) {
pr_err("overlayfs: failed to create directory %s/%s\n",
ufs->config.workdir, OVL_WORKDIR_NAME);
goto out_put_upper_mnt;
}
}
ufs->lower_mnt = kcalloc(1, sizeof(struct vfsmount *), GFP_KERNEL);
@ -858,8 +869,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
ufs->lower_mnt[0] = mnt;
ufs->numlower = 1;
/* If the upper fs is r/o, we mark overlayfs r/o too */
if (ufs->upper_mnt->mnt_sb->s_flags & MS_RDONLY)
/* If the upper fs is r/o or nonexistent, we mark overlayfs r/o too */
if (!ufs->upper_mnt || (ufs->upper_mnt->mnt_sb->s_flags & MS_RDONLY))
sb->s_flags |= MS_RDONLY;
sb->s_d_op = &ovl_dentry_operations;