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ovl: split out ovl_get_lower_layers() from ovl_fill_super()

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Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Miklos Szeredi 2017-11-09 10:23:28 +01:00
parent 8ed61dc37e
commit c0d91fb910
1 changed files with 52 additions and 38 deletions
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90
fs/overlayfs/super.c
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@ -1038,6 +1038,55 @@ out_free_stack:
goto out;
}
static int ovl_get_lower_layers(struct ovl_fs *ufs, struct path *stack,
unsigned int numlower)
{
int err;
unsigned int i;
err = -ENOMEM;
ufs->lower_layers = kcalloc(numlower, sizeof(struct ovl_layer),
GFP_KERNEL);
if (ufs->lower_layers == NULL)
goto out;
for (i = 0; i < numlower; i++) {
struct vfsmount *mnt;
dev_t dev;
err = get_anon_bdev(&dev);
if (err) {
pr_err("overlayfs: failed to get anonymous bdev for lowerpath\n");
goto out;
}
mnt = clone_private_mount(&stack[i]);
err = PTR_ERR(mnt);
if (IS_ERR(mnt)) {
pr_err("overlayfs: failed to clone lowerpath\n");
free_anon_bdev(dev);
goto out;
}
/*
* Make lower layers R/O. That way fchmod/fchown on lower file
* will fail instead of modifying lower fs.
*/
mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME;
ufs->lower_layers[ufs->numlower].mnt = mnt;
ufs->lower_layers[ufs->numlower].pseudo_dev = dev;
ufs->numlower++;
/* Check if all lower layers are on same sb */
if (i == 0)
ufs->same_sb = mnt->mnt_sb;
else if (ufs->same_sb != mnt->mnt_sb)
ufs->same_sb = NULL;
}
err = 0;
out:
return err;
}
static int ovl_fill_super(struct super_block *sb, void *data, int silent)
{
struct path upperpath = { };
@ -1103,44 +1152,9 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
goto out_put_workdir;
}
err = -ENOMEM;
ufs->lower_layers = kcalloc(numlower, sizeof(struct ovl_layer),
GFP_KERNEL);
if (ufs->lower_layers == NULL)
goto out_put_workdir;
for (i = 0; i < numlower; i++) {
struct vfsmount *mnt;
dev_t dev;
err = get_anon_bdev(&dev);
if (err) {
pr_err("overlayfs: failed to get anonymous bdev for lowerpath\n");
goto out_put_lower_layers;
}
mnt = clone_private_mount(&stack[i]);
err = PTR_ERR(mnt);
if (IS_ERR(mnt)) {
pr_err("overlayfs: failed to clone lowerpath\n");
free_anon_bdev(dev);
goto out_put_lower_layers;
}
/*
* Make lower layers R/O. That way fchmod/fchown on lower file
* will fail instead of modifying lower fs.
*/
mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME;
ufs->lower_layers[ufs->numlower].mnt = mnt;
ufs->lower_layers[ufs->numlower].pseudo_dev = dev;
ufs->numlower++;
/* Check if all lower layers are on same sb */
if (i == 0)
ufs->same_sb = mnt->mnt_sb;
else if (ufs->same_sb != mnt->mnt_sb)
ufs->same_sb = NULL;
}
err = ovl_get_lower_layers(ufs, stack, numlower);
if (err)
goto out_put_lower_layers;
/* If the upper fs is nonexistent, we mark overlayfs r/o too */
if (!ufs->upper_mnt)