ovl: split out ovl_get_lowerstack() from ovl_fill_super()

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 6d02ca31bb90a603d078aee478fca995f0522945..6c8703112b8f4a84703ab3dc6ba6d6ad45fc35f7 100644 (file)
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -895,6 +895,75 @@ out:
        return err;
 }
 
+static int ovl_get_lowerstack(struct super_block *sb, struct ovl_fs *ufs,
+                             struct path **stackp, unsigned int *stacklenp)
+{
+       int err;
+       char *lowertmp, *lower;
+       struct path *stack;
+       unsigned int stacklen, numlower, i;
+       bool remote = false;
+
+       err = -ENOMEM;
+       lowertmp = kstrdup(ufs->config.lowerdir, GFP_KERNEL);
+       if (!lowertmp)
+               goto out;
+
+       err = -EINVAL;
+       stacklen = ovl_split_lowerdirs(lowertmp);
+       if (stacklen > OVL_MAX_STACK) {
+               pr_err("overlayfs: too many lower directories, limit is %d\n",
+                      OVL_MAX_STACK);
+               goto out;
+       } else if (!ufs->config.upperdir && stacklen == 1) {
+               pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n");
+               goto out;
+       }
+
+       err = -ENOMEM;
+       stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL);
+       if (!stack)
+               goto out;
+
+       err = -EINVAL;
+       lower = lowertmp;
+       for (numlower = 0; numlower < stacklen; numlower++) {
+               err = ovl_lower_dir(lower, &stack[numlower], ufs,
+                                   &sb->s_stack_depth, &remote);
+               if (err)
+                       goto out_free_stack;
+
+               lower = strchr(lower, '\0') + 1;
+       }
+
+       err = -EINVAL;
+       sb->s_stack_depth++;
+       if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
+               pr_err("overlayfs: maximum fs stacking depth exceeded\n");
+               goto out_free_stack;
+       }
+
+       *stackp = stack;
+       *stacklenp = numlower;
+
+       if (remote)
+               sb->s_d_op = &ovl_reval_dentry_operations;
+       else
+               sb->s_d_op = &ovl_dentry_operations;
+
+       err = 0;
+
+out:
+       kfree(lowertmp);
+       return err;
+
+out_free_stack:
+       for (i = 0; i < numlower; i++)
+               path_put(&stack[i]);
+       kfree(stack);
+       goto out;
+}
+
 static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 {
        struct path upperpath = { };
@@ -903,12 +972,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
        struct ovl_entry *oe;
        struct ovl_fs *ufs;
        struct path *stack = NULL;
-       char *lowertmp;
-       char *lower;
-       unsigned int numlower;
-       unsigned int stacklen = 0;
+       unsigned int numlower = 0;
        unsigned int i;
-       bool remote = false;
        struct cred *cred;
        int err;
 
@@ -948,45 +1013,10 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 
                sb->s_stack_depth = upperpath.mnt->mnt_sb->s_stack_depth;
        }
-       err = -ENOMEM;
-       lowertmp = kstrdup(ufs->config.lowerdir, GFP_KERNEL);
-       if (!lowertmp)
+       err = ovl_get_lowerstack(sb, ufs, &stack, &numlower);
+       if (err)
                goto out_unlock_workdentry;
 
-       err = -EINVAL;
-       stacklen = ovl_split_lowerdirs(lowertmp);
-       if (stacklen > OVL_MAX_STACK) {
-               pr_err("overlayfs: too many lower directories, limit is %d\n",
-                      OVL_MAX_STACK);
-               goto out_free_lowertmp;
-       } else if (!ufs->config.upperdir && stacklen == 1) {
-               pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n");
-               goto out_free_lowertmp;
-       }
-
-       err = -ENOMEM;
-       stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL);
-       if (!stack)
-               goto out_free_lowertmp;
-
-       err = -EINVAL;
-       lower = lowertmp;
-       for (numlower = 0; numlower < stacklen; numlower++) {
-               err = ovl_lower_dir(lower, &stack[numlower], ufs,
-                                   &sb->s_stack_depth, &remote);
-               if (err)
-                       goto out_put_lowerpath;
-
-               lower = strchr(lower, '\0') + 1;
-       }
-
-       err = -EINVAL;
-       sb->s_stack_depth++;
-       if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
-               pr_err("overlayfs: maximum fs stacking depth exceeded\n");
-               goto out_put_lowerpath;
-       }
-
        if (ufs->config.upperdir) {
                ufs->upper_mnt = clone_private_mount(&upperpath);
                err = PTR_ERR(ufs->upper_mnt);
@@ -1145,11 +1175,6 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
        if (!ufs->indexdir)
                ufs->config.index = false;
 
-       if (remote)
-               sb->s_d_op = &ovl_reval_dentry_operations;
-       else
-               sb->s_d_op = &ovl_dentry_operations;
-
        err = -ENOMEM;
        ufs->creator_cred = cred = prepare_creds();
        if (!cred)
@@ -1173,7 +1198,6 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
                mntput(stack[i].mnt);
        kfree(stack);
        mntput(workpath.mnt);
-       kfree(lowertmp);
 
        if (upperpath.dentry) {
                oe->has_upper = true;
@@ -1212,8 +1236,6 @@ out_put_lowerpath:
        for (i = 0; i < numlower; i++)
                path_put(&stack[i]);
        kfree(stack);
-out_free_lowertmp:
-       kfree(lowertmp);
 out_unlock_workdentry:
        if (ufs->workdir_locked)
                ovl_inuse_unlock(workpath.dentry);