mcoverlayfs: add new base from 4.18.14
This just lays out new files so the next commit is easier to review; nothing changes here Change-Id: I66669877d2d10632f5436c0eeb32248cd4c8b996
This commit is contained in:
Dominique Martinet
678
executer/kernel/mcoverlayfs/linux-4.18.14/util.c
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678
executer/kernel/mcoverlayfs/linux-4.18.14/util.c
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@@ -0,0 +1,678 @@
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/*
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* Copyright (C) 2011 Novell Inc.
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* Copyright (C) 2016 Red Hat, Inc.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*/
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#include <linux/fs.h>
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#include <linux/mount.h>
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#include <linux/slab.h>
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#include <linux/cred.h>
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#include <linux/xattr.h>
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#include <linux/exportfs.h>
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#include <linux/uuid.h>
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#include <linux/namei.h>
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#include <linux/ratelimit.h>
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#include "overlayfs.h"
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int ovl_want_write(struct dentry *dentry)
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{
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struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
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return mnt_want_write(ofs->upper_mnt);
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}
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void ovl_drop_write(struct dentry *dentry)
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{
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struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
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mnt_drop_write(ofs->upper_mnt);
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}
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struct dentry *ovl_workdir(struct dentry *dentry)
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{
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struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
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return ofs->workdir;
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}
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const struct cred *ovl_override_creds(struct super_block *sb)
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{
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struct ovl_fs *ofs = sb->s_fs_info;
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return override_creds(ofs->creator_cred);
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}
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struct super_block *ovl_same_sb(struct super_block *sb)
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{
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struct ovl_fs *ofs = sb->s_fs_info;
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if (!ofs->numlowerfs)
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return ofs->upper_mnt->mnt_sb;
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else if (ofs->numlowerfs == 1 && !ofs->upper_mnt)
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return ofs->lower_fs[0].sb;
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else
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return NULL;
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}
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/*
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* Check if underlying fs supports file handles and try to determine encoding
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* type, in order to deduce maximum inode number used by fs.
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*
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* Return 0 if file handles are not supported.
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* Return 1 (FILEID_INO32_GEN) if fs uses the default 32bit inode encoding.
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* Return -1 if fs uses a non default encoding with unknown inode size.
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*/
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int ovl_can_decode_fh(struct super_block *sb)
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{
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if (!sb->s_export_op || !sb->s_export_op->fh_to_dentry ||
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uuid_is_null(&sb->s_uuid))
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return 0;
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return sb->s_export_op->encode_fh ? -1 : FILEID_INO32_GEN;
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}
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struct dentry *ovl_indexdir(struct super_block *sb)
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{
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struct ovl_fs *ofs = sb->s_fs_info;
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return ofs->indexdir;
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}
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/* Index all files on copy up. For now only enabled for NFS export */
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bool ovl_index_all(struct super_block *sb)
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{
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struct ovl_fs *ofs = sb->s_fs_info;
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return ofs->config.nfs_export && ofs->config.index;
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}
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/* Verify lower origin on lookup. For now only enabled for NFS export */
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bool ovl_verify_lower(struct super_block *sb)
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{
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struct ovl_fs *ofs = sb->s_fs_info;
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return ofs->config.nfs_export && ofs->config.index;
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}
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struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
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{
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size_t size = offsetof(struct ovl_entry, lowerstack[numlower]);
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struct ovl_entry *oe = kzalloc(size, GFP_KERNEL);
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if (oe)
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oe->numlower = numlower;
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return oe;
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}
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bool ovl_dentry_remote(struct dentry *dentry)
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{
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return dentry->d_flags &
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(DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE |
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DCACHE_OP_REAL);
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}
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bool ovl_dentry_weird(struct dentry *dentry)
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{
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return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT |
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DCACHE_MANAGE_TRANSIT |
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DCACHE_OP_HASH |
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DCACHE_OP_COMPARE);
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}
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enum ovl_path_type ovl_path_type(struct dentry *dentry)
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{
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struct ovl_entry *oe = dentry->d_fsdata;
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enum ovl_path_type type = 0;
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if (ovl_dentry_upper(dentry)) {
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type = __OVL_PATH_UPPER;
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/*
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* Non-dir dentry can hold lower dentry of its copy up origin.
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*/
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if (oe->numlower) {
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type |= __OVL_PATH_ORIGIN;
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if (d_is_dir(dentry))
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type |= __OVL_PATH_MERGE;
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}
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} else {
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if (oe->numlower > 1)
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type |= __OVL_PATH_MERGE;
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}
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return type;
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}
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void ovl_path_upper(struct dentry *dentry, struct path *path)
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{
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struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
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path->mnt = ofs->upper_mnt;
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path->dentry = ovl_dentry_upper(dentry);
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}
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void ovl_path_lower(struct dentry *dentry, struct path *path)
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{
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struct ovl_entry *oe = dentry->d_fsdata;
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if (oe->numlower) {
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path->mnt = oe->lowerstack[0].layer->mnt;
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path->dentry = oe->lowerstack[0].dentry;
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} else {
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*path = (struct path) { };
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}
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}
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enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
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{
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enum ovl_path_type type = ovl_path_type(dentry);
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if (!OVL_TYPE_UPPER(type))
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ovl_path_lower(dentry, path);
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else
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ovl_path_upper(dentry, path);
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return type;
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}
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struct dentry *ovl_dentry_upper(struct dentry *dentry)
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{
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return ovl_upperdentry_dereference(OVL_I(d_inode(dentry)));
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}
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struct dentry *ovl_dentry_lower(struct dentry *dentry)
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{
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struct ovl_entry *oe = dentry->d_fsdata;
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return oe->numlower ? oe->lowerstack[0].dentry : NULL;
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}
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struct ovl_layer *ovl_layer_lower(struct dentry *dentry)
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{
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struct ovl_entry *oe = dentry->d_fsdata;
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return oe->numlower ? oe->lowerstack[0].layer : NULL;
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}
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struct dentry *ovl_dentry_real(struct dentry *dentry)
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{
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return ovl_dentry_upper(dentry) ?: ovl_dentry_lower(dentry);
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}
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struct dentry *ovl_i_dentry_upper(struct inode *inode)
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{
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return ovl_upperdentry_dereference(OVL_I(inode));
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}
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struct inode *ovl_inode_upper(struct inode *inode)
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{
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struct dentry *upperdentry = ovl_i_dentry_upper(inode);
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return upperdentry ? d_inode(upperdentry) : NULL;
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}
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struct inode *ovl_inode_lower(struct inode *inode)
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{
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return OVL_I(inode)->lower;
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}
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struct inode *ovl_inode_real(struct inode *inode)
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{
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return ovl_inode_upper(inode) ?: ovl_inode_lower(inode);
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}
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struct ovl_dir_cache *ovl_dir_cache(struct inode *inode)
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{
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return OVL_I(inode)->cache;
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}
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void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache)
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{
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OVL_I(inode)->cache = cache;
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}
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void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry)
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{
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set_bit(flag, &OVL_E(dentry)->flags);
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}
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void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry)
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{
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clear_bit(flag, &OVL_E(dentry)->flags);
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}
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bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry)
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{
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return test_bit(flag, &OVL_E(dentry)->flags);
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}
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bool ovl_dentry_is_opaque(struct dentry *dentry)
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{
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return ovl_dentry_test_flag(OVL_E_OPAQUE, dentry);
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}
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bool ovl_dentry_is_whiteout(struct dentry *dentry)
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{
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return !dentry->d_inode && ovl_dentry_is_opaque(dentry);
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}
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void ovl_dentry_set_opaque(struct dentry *dentry)
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{
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ovl_dentry_set_flag(OVL_E_OPAQUE, dentry);
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}
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/*
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* For hard links and decoded file handles, it's possible for ovl_dentry_upper()
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* to return positive, while there's no actual upper alias for the inode.
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* Copy up code needs to know about the existence of the upper alias, so it
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* can't use ovl_dentry_upper().
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*/
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bool ovl_dentry_has_upper_alias(struct dentry *dentry)
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{
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return ovl_dentry_test_flag(OVL_E_UPPER_ALIAS, dentry);
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}
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void ovl_dentry_set_upper_alias(struct dentry *dentry)
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{
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ovl_dentry_set_flag(OVL_E_UPPER_ALIAS, dentry);
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}
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bool ovl_redirect_dir(struct super_block *sb)
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{
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struct ovl_fs *ofs = sb->s_fs_info;
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return ofs->config.redirect_dir && !ofs->noxattr;
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}
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const char *ovl_dentry_get_redirect(struct dentry *dentry)
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{
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return OVL_I(d_inode(dentry))->redirect;
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}
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void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect)
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{
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struct ovl_inode *oi = OVL_I(d_inode(dentry));
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kfree(oi->redirect);
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oi->redirect = redirect;
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}
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void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
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struct dentry *lowerdentry)
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{
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struct inode *realinode = d_inode(upperdentry ?: lowerdentry);
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if (upperdentry)
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OVL_I(inode)->__upperdentry = upperdentry;
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if (lowerdentry)
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OVL_I(inode)->lower = igrab(d_inode(lowerdentry));
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ovl_copyattr(realinode, inode);
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if (!inode->i_ino)
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inode->i_ino = realinode->i_ino;
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}
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void ovl_inode_update(struct inode *inode, struct dentry *upperdentry)
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{
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struct inode *upperinode = d_inode(upperdentry);
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WARN_ON(OVL_I(inode)->__upperdentry);
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/*
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* Make sure upperdentry is consistent before making it visible
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*/
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smp_wmb();
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OVL_I(inode)->__upperdentry = upperdentry;
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if (inode_unhashed(inode)) {
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if (!inode->i_ino)
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inode->i_ino = upperinode->i_ino;
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inode->i_private = upperinode;
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__insert_inode_hash(inode, (unsigned long) upperinode);
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}
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}
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void ovl_dentry_version_inc(struct dentry *dentry, bool impurity)
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{
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struct inode *inode = d_inode(dentry);
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WARN_ON(!inode_is_locked(inode));
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/*
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* Version is used by readdir code to keep cache consistent. For merge
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* dirs all changes need to be noted. For non-merge dirs, cache only
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* contains impure (ones which have been copied up and have origins)
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* entries, so only need to note changes to impure entries.
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*/
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if (OVL_TYPE_MERGE(ovl_path_type(dentry)) || impurity)
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OVL_I(inode)->version++;
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}
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u64 ovl_dentry_version_get(struct dentry *dentry)
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{
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struct inode *inode = d_inode(dentry);
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WARN_ON(!inode_is_locked(inode));
|
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return OVL_I(inode)->version;
|
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}
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|
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bool ovl_is_whiteout(struct dentry *dentry)
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{
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struct inode *inode = dentry->d_inode;
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return inode && IS_WHITEOUT(inode);
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}
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struct file *ovl_path_open(struct path *path, int flags)
|
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{
|
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return dentry_open(path, flags | O_NOATIME, current_cred());
|
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}
|
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|
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int ovl_copy_up_start(struct dentry *dentry)
|
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{
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struct ovl_inode *oi = OVL_I(d_inode(dentry));
|
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int err;
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err = mutex_lock_interruptible(&oi->lock);
|
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if (!err && ovl_dentry_has_upper_alias(dentry)) {
|
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err = 1; /* Already copied up */
|
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mutex_unlock(&oi->lock);
|
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}
|
||||
|
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return err;
|
||||
}
|
||||
|
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void ovl_copy_up_end(struct dentry *dentry)
|
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{
|
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mutex_unlock(&OVL_I(d_inode(dentry))->lock);
|
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}
|
||||
|
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bool ovl_check_origin_xattr(struct dentry *dentry)
|
||||
{
|
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int res;
|
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|
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res = vfs_getxattr(dentry, OVL_XATTR_ORIGIN, NULL, 0);
|
||||
|
||||
/* Zero size value means "copied up but origin unknown" */
|
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if (res >= 0)
|
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return true;
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
bool ovl_check_dir_xattr(struct dentry *dentry, const char *name)
|
||||
{
|
||||
int res;
|
||||
char val;
|
||||
|
||||
if (!d_is_dir(dentry))
|
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return false;
|
||||
|
||||
res = vfs_getxattr(dentry, name, &val, 1);
|
||||
if (res == 1 && val == 'y')
|
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return true;
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
|
||||
const char *name, const void *value, size_t size,
|
||||
int xerr)
|
||||
{
|
||||
int err;
|
||||
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
|
||||
|
||||
if (ofs->noxattr)
|
||||
return xerr;
|
||||
|
||||
err = ovl_do_setxattr(upperdentry, name, value, size, 0);
|
||||
|
||||
if (err == -EOPNOTSUPP) {
|
||||
pr_warn("overlayfs: cannot set %s xattr on upper\n", name);
|
||||
ofs->noxattr = true;
|
||||
return xerr;
|
||||
}
|
||||
|
||||
return err;
|
||||
}
|
||||
|
||||
int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry)
|
||||
{
|
||||
int err;
|
||||
|
||||
if (ovl_test_flag(OVL_IMPURE, d_inode(dentry)))
|
||||
return 0;
|
||||
|
||||
/*
|
||||
* Do not fail when upper doesn't support xattrs.
|
||||
* Upper inodes won't have origin nor redirect xattr anyway.
|
||||
*/
|
||||
err = ovl_check_setxattr(dentry, upperdentry, OVL_XATTR_IMPURE,
|
||||
"y", 1, 0);
|
||||
if (!err)
|
||||
ovl_set_flag(OVL_IMPURE, d_inode(dentry));
|
||||
|
||||
return err;
|
||||
}
|
||||
|
||||
void ovl_set_flag(unsigned long flag, struct inode *inode)
|
||||
{
|
||||
set_bit(flag, &OVL_I(inode)->flags);
|
||||
}
|
||||
|
||||
void ovl_clear_flag(unsigned long flag, struct inode *inode)
|
||||
{
|
||||
clear_bit(flag, &OVL_I(inode)->flags);
|
||||
}
|
||||
|
||||
bool ovl_test_flag(unsigned long flag, struct inode *inode)
|
||||
{
|
||||
return test_bit(flag, &OVL_I(inode)->flags);
|
||||
}
|
||||
|
||||
/**
|
||||
* Caller must hold a reference to inode to prevent it from being freed while
|
||||
* it is marked inuse.
|
||||
*/
|
||||
bool ovl_inuse_trylock(struct dentry *dentry)
|
||||
{
|
||||
struct inode *inode = d_inode(dentry);
|
||||
bool locked = false;
|
||||
|
||||
spin_lock(&inode->i_lock);
|
||||
if (!(inode->i_state & I_OVL_INUSE)) {
|
||||
inode->i_state |= I_OVL_INUSE;
|
||||
locked = true;
|
||||
}
|
||||
spin_unlock(&inode->i_lock);
|
||||
|
||||
return locked;
|
||||
}
|
||||
|
||||
void ovl_inuse_unlock(struct dentry *dentry)
|
||||
{
|
||||
if (dentry) {
|
||||
struct inode *inode = d_inode(dentry);
|
||||
|
||||
spin_lock(&inode->i_lock);
|
||||
WARN_ON(!(inode->i_state & I_OVL_INUSE));
|
||||
inode->i_state &= ~I_OVL_INUSE;
|
||||
spin_unlock(&inode->i_lock);
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Does this overlay dentry need to be indexed on copy up?
|
||||
*/
|
||||
bool ovl_need_index(struct dentry *dentry)
|
||||
{
|
||||
struct dentry *lower = ovl_dentry_lower(dentry);
|
||||
|
||||
if (!lower || !ovl_indexdir(dentry->d_sb))
|
||||
return false;
|
||||
|
||||
/* Index all files for NFS export and consistency verification */
|
||||
if (ovl_index_all(dentry->d_sb))
|
||||
return true;
|
||||
|
||||
/* Index only lower hardlinks on copy up */
|
||||
if (!d_is_dir(lower) && d_inode(lower)->i_nlink > 1)
|
||||
return true;
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
/* Caller must hold OVL_I(inode)->lock */
|
||||
static void ovl_cleanup_index(struct dentry *dentry)
|
||||
{
|
||||
struct dentry *indexdir = ovl_indexdir(dentry->d_sb);
|
||||
struct inode *dir = indexdir->d_inode;
|
||||
struct dentry *lowerdentry = ovl_dentry_lower(dentry);
|
||||
struct dentry *upperdentry = ovl_dentry_upper(dentry);
|
||||
struct dentry *index = NULL;
|
||||
struct inode *inode;
|
||||
struct qstr name = { };
|
||||
int err;
|
||||
|
||||
err = ovl_get_index_name(lowerdentry, &name);
|
||||
if (err)
|
||||
goto fail;
|
||||
|
||||
inode = d_inode(upperdentry);
|
||||
if (!S_ISDIR(inode->i_mode) && inode->i_nlink != 1) {
|
||||
pr_warn_ratelimited("overlayfs: cleanup linked index (%pd2, ino=%lu, nlink=%u)\n",
|
||||
upperdentry, inode->i_ino, inode->i_nlink);
|
||||
/*
|
||||
* We either have a bug with persistent union nlink or a lower
|
||||
* hardlink was added while overlay is mounted. Adding a lower
|
||||
* hardlink and then unlinking all overlay hardlinks would drop
|
||||
* overlay nlink to zero before all upper inodes are unlinked.
|
||||
* As a safety measure, when that situation is detected, set
|
||||
* the overlay nlink to the index inode nlink minus one for the
|
||||
* index entry itself.
|
||||
*/
|
||||
set_nlink(d_inode(dentry), inode->i_nlink - 1);
|
||||
ovl_set_nlink_upper(dentry);
|
||||
goto out;
|
||||
}
|
||||
|
||||
inode_lock_nested(dir, I_MUTEX_PARENT);
|
||||
index = lookup_one_len(name.name, indexdir, name.len);
|
||||
err = PTR_ERR(index);
|
||||
if (IS_ERR(index)) {
|
||||
index = NULL;
|
||||
} else if (ovl_index_all(dentry->d_sb)) {
|
||||
/* Whiteout orphan index to block future open by handle */
|
||||
err = ovl_cleanup_and_whiteout(indexdir, dir, index);
|
||||
} else {
|
||||
/* Cleanup orphan index entries */
|
||||
err = ovl_cleanup(dir, index);
|
||||
}
|
||||
|
||||
inode_unlock(dir);
|
||||
if (err)
|
||||
goto fail;
|
||||
|
||||
out:
|
||||
kfree(name.name);
|
||||
dput(index);
|
||||
return;
|
||||
|
||||
fail:
|
||||
pr_err("overlayfs: cleanup index of '%pd2' failed (%i)\n", dentry, err);
|
||||
goto out;
|
||||
}
|
||||
|
||||
/*
|
||||
* Operations that change overlay inode and upper inode nlink need to be
|
||||
* synchronized with copy up for persistent nlink accounting.
|
||||
*/
|
||||
int ovl_nlink_start(struct dentry *dentry, bool *locked)
|
||||
{
|
||||
struct ovl_inode *oi = OVL_I(d_inode(dentry));
|
||||
const struct cred *old_cred;
|
||||
int err;
|
||||
|
||||
if (!d_inode(dentry))
|
||||
return 0;
|
||||
|
||||
/*
|
||||
* With inodes index is enabled, we store the union overlay nlink
|
||||
* in an xattr on the index inode. When whiting out an indexed lower,
|
||||
* we need to decrement the overlay persistent nlink, but before the
|
||||
* first copy up, we have no upper index inode to store the xattr.
|
||||
*
|
||||
* As a workaround, before whiteout/rename over an indexed lower,
|
||||
* copy up to create the upper index. Creating the upper index will
|
||||
* initialize the overlay nlink, so it could be dropped if unlink
|
||||
* or rename succeeds.
|
||||
*
|
||||
* TODO: implement metadata only index copy up when called with
|
||||
* ovl_copy_up_flags(dentry, O_PATH).
|
||||
*/
|
||||
if (ovl_need_index(dentry) && !ovl_dentry_has_upper_alias(dentry)) {
|
||||
err = ovl_copy_up(dentry);
|
||||
if (err)
|
||||
return err;
|
||||
}
|
||||
|
||||
err = mutex_lock_interruptible(&oi->lock);
|
||||
if (err)
|
||||
return err;
|
||||
|
||||
if (d_is_dir(dentry) || !ovl_test_flag(OVL_INDEX, d_inode(dentry)))
|
||||
goto out;
|
||||
|
||||
old_cred = ovl_override_creds(dentry->d_sb);
|
||||
/*
|
||||
* The overlay inode nlink should be incremented/decremented IFF the
|
||||
* upper operation succeeds, along with nlink change of upper inode.
|
||||
* Therefore, before link/unlink/rename, we store the union nlink
|
||||
* value relative to the upper inode nlink in an upper inode xattr.
|
||||
*/
|
||||
err = ovl_set_nlink_upper(dentry);
|
||||
revert_creds(old_cred);
|
||||
|
||||
out:
|
||||
if (err)
|
||||
mutex_unlock(&oi->lock);
|
||||
else
|
||||
*locked = true;
|
||||
|
||||
return err;
|
||||
}
|
||||
|
||||
void ovl_nlink_end(struct dentry *dentry, bool locked)
|
||||
{
|
||||
if (locked) {
|
||||
if (ovl_test_flag(OVL_INDEX, d_inode(dentry)) &&
|
||||
d_inode(dentry)->i_nlink == 0) {
|
||||
const struct cred *old_cred;
|
||||
|
||||
old_cred = ovl_override_creds(dentry->d_sb);
|
||||
ovl_cleanup_index(dentry);
|
||||
revert_creds(old_cred);
|
||||
}
|
||||
|
||||
mutex_unlock(&OVL_I(d_inode(dentry))->lock);
|
||||
}
|
||||
}
|
||||
|
||||
int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir)
|
||||
{
|
||||
/* Workdir should not be the same as upperdir */
|
||||
if (workdir == upperdir)
|
||||
goto err;
|
||||
|
||||
/* Workdir should not be subdir of upperdir and vice versa */
|
||||
if (lock_rename(workdir, upperdir) != NULL)
|
||||
goto err_unlock;
|
||||
|
||||
return 0;
|
||||
|
||||
err_unlock:
|
||||
unlock_rename(workdir, upperdir);
|
||||
err:
|
||||
pr_err("overlayfs: failed to lock workdir+upperdir\n");
|
||||
return -EIO;
|
||||
}
|
||||
Reference in New Issue
Block a user