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![Muchun Song](/assets/img/avatar_default.png)
The inode allocation is supposed to use alloc_inode_sb(), so convert kmem_cache_alloc() of all filesystems to alloc_inode_sb(). Link: https://lkml.kernel.org/r/20220228122126.37293-5-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Theodore Ts'o <tytso@mit.edu> [ext4] Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Cc: Alex Shi <alexs@kernel.org> Cc: Anna Schumaker <Anna.Schumaker@Netapp.com> Cc: Chao Yu <chao@kernel.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Fam Zheng <fam.zheng@bytedance.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kari Argillander <kari.argillander@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Xiongchun Duan <duanxiongchun@bytedance.com> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2220 lines
54 KiB
C
2220 lines
54 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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*
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* Copyright (C) 2011 Novell Inc.
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*/
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#include <uapi/linux/magic.h>
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#include <linux/fs.h>
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#include <linux/namei.h>
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#include <linux/xattr.h>
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#include <linux/mount.h>
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#include <linux/parser.h>
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#include <linux/module.h>
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#include <linux/statfs.h>
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#include <linux/seq_file.h>
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#include <linux/posix_acl_xattr.h>
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#include <linux/exportfs.h>
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#include "overlayfs.h"
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MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
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MODULE_DESCRIPTION("Overlay filesystem");
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MODULE_LICENSE("GPL");
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struct ovl_dir_cache;
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#define OVL_MAX_STACK 500
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static bool ovl_redirect_dir_def = IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_DIR);
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module_param_named(redirect_dir, ovl_redirect_dir_def, bool, 0644);
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MODULE_PARM_DESC(redirect_dir,
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"Default to on or off for the redirect_dir feature");
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static bool ovl_redirect_always_follow =
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IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_ALWAYS_FOLLOW);
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module_param_named(redirect_always_follow, ovl_redirect_always_follow,
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bool, 0644);
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MODULE_PARM_DESC(redirect_always_follow,
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"Follow redirects even if redirect_dir feature is turned off");
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static bool ovl_index_def = IS_ENABLED(CONFIG_OVERLAY_FS_INDEX);
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module_param_named(index, ovl_index_def, bool, 0644);
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MODULE_PARM_DESC(index,
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"Default to on or off for the inodes index feature");
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static bool ovl_nfs_export_def = IS_ENABLED(CONFIG_OVERLAY_FS_NFS_EXPORT);
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module_param_named(nfs_export, ovl_nfs_export_def, bool, 0644);
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MODULE_PARM_DESC(nfs_export,
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"Default to on or off for the NFS export feature");
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static bool ovl_xino_auto_def = IS_ENABLED(CONFIG_OVERLAY_FS_XINO_AUTO);
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module_param_named(xino_auto, ovl_xino_auto_def, bool, 0644);
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MODULE_PARM_DESC(xino_auto,
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"Auto enable xino feature");
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static void ovl_entry_stack_free(struct ovl_entry *oe)
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{
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unsigned int i;
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for (i = 0; i < oe->numlower; i++)
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dput(oe->lowerstack[i].dentry);
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}
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static bool ovl_metacopy_def = IS_ENABLED(CONFIG_OVERLAY_FS_METACOPY);
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module_param_named(metacopy, ovl_metacopy_def, bool, 0644);
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MODULE_PARM_DESC(metacopy,
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"Default to on or off for the metadata only copy up feature");
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static void ovl_dentry_release(struct dentry *dentry)
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{
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struct ovl_entry *oe = dentry->d_fsdata;
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if (oe) {
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ovl_entry_stack_free(oe);
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kfree_rcu(oe, rcu);
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}
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}
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static struct dentry *ovl_d_real(struct dentry *dentry,
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const struct inode *inode)
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{
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struct dentry *real = NULL, *lower;
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/* It's an overlay file */
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if (inode && d_inode(dentry) == inode)
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return dentry;
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if (!d_is_reg(dentry)) {
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if (!inode || inode == d_inode(dentry))
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return dentry;
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goto bug;
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}
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real = ovl_dentry_upper(dentry);
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if (real && (inode == d_inode(real)))
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return real;
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if (real && !inode && ovl_has_upperdata(d_inode(dentry)))
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return real;
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lower = ovl_dentry_lowerdata(dentry);
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if (!lower)
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goto bug;
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real = lower;
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/* Handle recursion */
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real = d_real(real, inode);
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if (!inode || inode == d_inode(real))
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return real;
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bug:
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WARN(1, "%s(%pd4, %s:%lu): real dentry (%p/%lu) not found\n",
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__func__, dentry, inode ? inode->i_sb->s_id : "NULL",
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inode ? inode->i_ino : 0, real,
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real && d_inode(real) ? d_inode(real)->i_ino : 0);
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return dentry;
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}
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static int ovl_revalidate_real(struct dentry *d, unsigned int flags, bool weak)
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{
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int ret = 1;
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if (weak) {
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if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE)
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ret = d->d_op->d_weak_revalidate(d, flags);
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} else if (d->d_flags & DCACHE_OP_REVALIDATE) {
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ret = d->d_op->d_revalidate(d, flags);
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if (!ret) {
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if (!(flags & LOOKUP_RCU))
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d_invalidate(d);
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ret = -ESTALE;
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}
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}
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return ret;
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}
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static int ovl_dentry_revalidate_common(struct dentry *dentry,
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unsigned int flags, bool weak)
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{
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struct ovl_entry *oe = dentry->d_fsdata;
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struct dentry *upper;
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unsigned int i;
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int ret = 1;
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upper = ovl_dentry_upper(dentry);
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if (upper)
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ret = ovl_revalidate_real(upper, flags, weak);
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for (i = 0; ret > 0 && i < oe->numlower; i++) {
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ret = ovl_revalidate_real(oe->lowerstack[i].dentry, flags,
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weak);
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}
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return ret;
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}
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static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags)
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{
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return ovl_dentry_revalidate_common(dentry, flags, false);
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}
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static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags)
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{
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return ovl_dentry_revalidate_common(dentry, flags, true);
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}
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static const struct dentry_operations ovl_dentry_operations = {
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.d_release = ovl_dentry_release,
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.d_real = ovl_d_real,
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.d_revalidate = ovl_dentry_revalidate,
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.d_weak_revalidate = ovl_dentry_weak_revalidate,
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};
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static struct kmem_cache *ovl_inode_cachep;
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static struct inode *ovl_alloc_inode(struct super_block *sb)
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{
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struct ovl_inode *oi = alloc_inode_sb(sb, ovl_inode_cachep, GFP_KERNEL);
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if (!oi)
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return NULL;
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oi->cache = NULL;
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oi->redirect = NULL;
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oi->version = 0;
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oi->flags = 0;
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oi->__upperdentry = NULL;
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oi->lower = NULL;
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oi->lowerdata = NULL;
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mutex_init(&oi->lock);
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return &oi->vfs_inode;
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}
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static void ovl_free_inode(struct inode *inode)
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{
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struct ovl_inode *oi = OVL_I(inode);
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kfree(oi->redirect);
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mutex_destroy(&oi->lock);
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kmem_cache_free(ovl_inode_cachep, oi);
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}
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static void ovl_destroy_inode(struct inode *inode)
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{
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struct ovl_inode *oi = OVL_I(inode);
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dput(oi->__upperdentry);
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iput(oi->lower);
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if (S_ISDIR(inode->i_mode))
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ovl_dir_cache_free(inode);
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else
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iput(oi->lowerdata);
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}
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static void ovl_free_fs(struct ovl_fs *ofs)
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{
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struct vfsmount **mounts;
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unsigned i;
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iput(ofs->workbasedir_trap);
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iput(ofs->indexdir_trap);
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iput(ofs->workdir_trap);
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dput(ofs->whiteout);
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dput(ofs->indexdir);
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dput(ofs->workdir);
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if (ofs->workdir_locked)
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ovl_inuse_unlock(ofs->workbasedir);
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dput(ofs->workbasedir);
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if (ofs->upperdir_locked)
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ovl_inuse_unlock(ovl_upper_mnt(ofs)->mnt_root);
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/* Hack! Reuse ofs->layers as a vfsmount array before freeing it */
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mounts = (struct vfsmount **) ofs->layers;
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for (i = 0; i < ofs->numlayer; i++) {
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iput(ofs->layers[i].trap);
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mounts[i] = ofs->layers[i].mnt;
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}
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kern_unmount_array(mounts, ofs->numlayer);
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kfree(ofs->layers);
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for (i = 0; i < ofs->numfs; i++)
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free_anon_bdev(ofs->fs[i].pseudo_dev);
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kfree(ofs->fs);
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kfree(ofs->config.lowerdir);
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kfree(ofs->config.upperdir);
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kfree(ofs->config.workdir);
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kfree(ofs->config.redirect_mode);
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if (ofs->creator_cred)
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put_cred(ofs->creator_cred);
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kfree(ofs);
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}
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static void ovl_put_super(struct super_block *sb)
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{
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struct ovl_fs *ofs = sb->s_fs_info;
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ovl_free_fs(ofs);
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}
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/* Sync real dirty inodes in upper filesystem (if it exists) */
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static int ovl_sync_fs(struct super_block *sb, int wait)
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{
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struct ovl_fs *ofs = sb->s_fs_info;
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struct super_block *upper_sb;
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int ret;
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ret = ovl_sync_status(ofs);
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/*
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* We have to always set the err, because the return value isn't
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* checked in syncfs, and instead indirectly return an error via
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* the sb's writeback errseq, which VFS inspects after this call.
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*/
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if (ret < 0) {
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errseq_set(&sb->s_wb_err, -EIO);
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return -EIO;
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}
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if (!ret)
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return ret;
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/*
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* Not called for sync(2) call or an emergency sync (SB_I_SKIP_SYNC).
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* All the super blocks will be iterated, including upper_sb.
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*
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* If this is a syncfs(2) call, then we do need to call
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* sync_filesystem() on upper_sb, but enough if we do it when being
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* called with wait == 1.
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*/
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if (!wait)
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return 0;
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upper_sb = ovl_upper_mnt(ofs)->mnt_sb;
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down_read(&upper_sb->s_umount);
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ret = sync_filesystem(upper_sb);
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up_read(&upper_sb->s_umount);
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return ret;
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}
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/**
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* ovl_statfs
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* @sb: The overlayfs super block
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* @buf: The struct kstatfs to fill in with stats
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*
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* Get the filesystem statistics. As writes always target the upper layer
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* filesystem pass the statfs to the upper filesystem (if it exists)
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*/
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static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf)
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{
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struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
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struct dentry *root_dentry = dentry->d_sb->s_root;
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struct path path;
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int err;
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ovl_path_real(root_dentry, &path);
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err = vfs_statfs(&path, buf);
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if (!err) {
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buf->f_namelen = ofs->namelen;
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buf->f_type = OVERLAYFS_SUPER_MAGIC;
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}
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return err;
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}
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/* Will this overlay be forced to mount/remount ro? */
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static bool ovl_force_readonly(struct ovl_fs *ofs)
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{
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return (!ovl_upper_mnt(ofs) || !ofs->workdir);
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}
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static const char *ovl_redirect_mode_def(void)
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{
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return ovl_redirect_dir_def ? "on" : "off";
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}
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static const char * const ovl_xino_str[] = {
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"off",
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"auto",
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"on",
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};
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static inline int ovl_xino_def(void)
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{
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return ovl_xino_auto_def ? OVL_XINO_AUTO : OVL_XINO_OFF;
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}
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/**
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* ovl_show_options
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*
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* Prints the mount options for a given superblock.
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* Returns zero; does not fail.
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*/
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static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
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{
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struct super_block *sb = dentry->d_sb;
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struct ovl_fs *ofs = sb->s_fs_info;
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seq_show_option(m, "lowerdir", ofs->config.lowerdir);
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if (ofs->config.upperdir) {
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seq_show_option(m, "upperdir", ofs->config.upperdir);
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seq_show_option(m, "workdir", ofs->config.workdir);
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}
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if (ofs->config.default_permissions)
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seq_puts(m, ",default_permissions");
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if (strcmp(ofs->config.redirect_mode, ovl_redirect_mode_def()) != 0)
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seq_printf(m, ",redirect_dir=%s", ofs->config.redirect_mode);
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if (ofs->config.index != ovl_index_def)
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seq_printf(m, ",index=%s", ofs->config.index ? "on" : "off");
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if (!ofs->config.uuid)
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seq_puts(m, ",uuid=off");
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if (ofs->config.nfs_export != ovl_nfs_export_def)
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seq_printf(m, ",nfs_export=%s", ofs->config.nfs_export ?
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"on" : "off");
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if (ofs->config.xino != ovl_xino_def() && !ovl_same_fs(sb))
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seq_printf(m, ",xino=%s", ovl_xino_str[ofs->config.xino]);
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if (ofs->config.metacopy != ovl_metacopy_def)
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seq_printf(m, ",metacopy=%s",
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ofs->config.metacopy ? "on" : "off");
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if (ofs->config.ovl_volatile)
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seq_puts(m, ",volatile");
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if (ofs->config.userxattr)
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seq_puts(m, ",userxattr");
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return 0;
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}
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static int ovl_remount(struct super_block *sb, int *flags, char *data)
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{
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struct ovl_fs *ofs = sb->s_fs_info;
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struct super_block *upper_sb;
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int ret = 0;
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if (!(*flags & SB_RDONLY) && ovl_force_readonly(ofs))
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return -EROFS;
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if (*flags & SB_RDONLY && !sb_rdonly(sb)) {
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upper_sb = ovl_upper_mnt(ofs)->mnt_sb;
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if (ovl_should_sync(ofs)) {
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down_read(&upper_sb->s_umount);
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ret = sync_filesystem(upper_sb);
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up_read(&upper_sb->s_umount);
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}
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}
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return ret;
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}
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static const struct super_operations ovl_super_operations = {
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.alloc_inode = ovl_alloc_inode,
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.free_inode = ovl_free_inode,
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.destroy_inode = ovl_destroy_inode,
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.drop_inode = generic_delete_inode,
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.put_super = ovl_put_super,
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.sync_fs = ovl_sync_fs,
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.statfs = ovl_statfs,
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.show_options = ovl_show_options,
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.remount_fs = ovl_remount,
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};
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enum {
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OPT_LOWERDIR,
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OPT_UPPERDIR,
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OPT_WORKDIR,
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OPT_DEFAULT_PERMISSIONS,
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OPT_REDIRECT_DIR,
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OPT_INDEX_ON,
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OPT_INDEX_OFF,
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OPT_UUID_ON,
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OPT_UUID_OFF,
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OPT_NFS_EXPORT_ON,
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OPT_USERXATTR,
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OPT_NFS_EXPORT_OFF,
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OPT_XINO_ON,
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OPT_XINO_OFF,
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OPT_XINO_AUTO,
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OPT_METACOPY_ON,
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OPT_METACOPY_OFF,
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OPT_VOLATILE,
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OPT_ERR,
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};
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static const match_table_t ovl_tokens = {
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{OPT_LOWERDIR, "lowerdir=%s"},
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{OPT_UPPERDIR, "upperdir=%s"},
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{OPT_WORKDIR, "workdir=%s"},
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{OPT_DEFAULT_PERMISSIONS, "default_permissions"},
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{OPT_REDIRECT_DIR, "redirect_dir=%s"},
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{OPT_INDEX_ON, "index=on"},
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{OPT_INDEX_OFF, "index=off"},
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{OPT_USERXATTR, "userxattr"},
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{OPT_UUID_ON, "uuid=on"},
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{OPT_UUID_OFF, "uuid=off"},
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{OPT_NFS_EXPORT_ON, "nfs_export=on"},
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{OPT_NFS_EXPORT_OFF, "nfs_export=off"},
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{OPT_XINO_ON, "xino=on"},
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{OPT_XINO_OFF, "xino=off"},
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{OPT_XINO_AUTO, "xino=auto"},
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{OPT_METACOPY_ON, "metacopy=on"},
|
|
{OPT_METACOPY_OFF, "metacopy=off"},
|
|
{OPT_VOLATILE, "volatile"},
|
|
{OPT_ERR, NULL}
|
|
};
|
|
|
|
static char *ovl_next_opt(char **s)
|
|
{
|
|
char *sbegin = *s;
|
|
char *p;
|
|
|
|
if (sbegin == NULL)
|
|
return NULL;
|
|
|
|
for (p = sbegin; *p; p++) {
|
|
if (*p == '\\') {
|
|
p++;
|
|
if (!*p)
|
|
break;
|
|
} else if (*p == ',') {
|
|
*p = '\0';
|
|
*s = p + 1;
|
|
return sbegin;
|
|
}
|
|
}
|
|
*s = NULL;
|
|
return sbegin;
|
|
}
|
|
|
|
static int ovl_parse_redirect_mode(struct ovl_config *config, const char *mode)
|
|
{
|
|
if (strcmp(mode, "on") == 0) {
|
|
config->redirect_dir = true;
|
|
/*
|
|
* Does not make sense to have redirect creation without
|
|
* redirect following.
|
|
*/
|
|
config->redirect_follow = true;
|
|
} else if (strcmp(mode, "follow") == 0) {
|
|
config->redirect_follow = true;
|
|
} else if (strcmp(mode, "off") == 0) {
|
|
if (ovl_redirect_always_follow)
|
|
config->redirect_follow = true;
|
|
} else if (strcmp(mode, "nofollow") != 0) {
|
|
pr_err("bad mount option \"redirect_dir=%s\"\n",
|
|
mode);
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int ovl_parse_opt(char *opt, struct ovl_config *config)
|
|
{
|
|
char *p;
|
|
int err;
|
|
bool metacopy_opt = false, redirect_opt = false;
|
|
bool nfs_export_opt = false, index_opt = false;
|
|
|
|
config->redirect_mode = kstrdup(ovl_redirect_mode_def(), GFP_KERNEL);
|
|
if (!config->redirect_mode)
|
|
return -ENOMEM;
|
|
|
|
while ((p = ovl_next_opt(&opt)) != NULL) {
|
|
int token;
|
|
substring_t args[MAX_OPT_ARGS];
|
|
|
|
if (!*p)
|
|
continue;
|
|
|
|
token = match_token(p, ovl_tokens, args);
|
|
switch (token) {
|
|
case OPT_UPPERDIR:
|
|
kfree(config->upperdir);
|
|
config->upperdir = match_strdup(&args[0]);
|
|
if (!config->upperdir)
|
|
return -ENOMEM;
|
|
break;
|
|
|
|
case OPT_LOWERDIR:
|
|
kfree(config->lowerdir);
|
|
config->lowerdir = match_strdup(&args[0]);
|
|
if (!config->lowerdir)
|
|
return -ENOMEM;
|
|
break;
|
|
|
|
case OPT_WORKDIR:
|
|
kfree(config->workdir);
|
|
config->workdir = match_strdup(&args[0]);
|
|
if (!config->workdir)
|
|
return -ENOMEM;
|
|
break;
|
|
|
|
case OPT_DEFAULT_PERMISSIONS:
|
|
config->default_permissions = true;
|
|
break;
|
|
|
|
case OPT_REDIRECT_DIR:
|
|
kfree(config->redirect_mode);
|
|
config->redirect_mode = match_strdup(&args[0]);
|
|
if (!config->redirect_mode)
|
|
return -ENOMEM;
|
|
redirect_opt = true;
|
|
break;
|
|
|
|
case OPT_INDEX_ON:
|
|
config->index = true;
|
|
index_opt = true;
|
|
break;
|
|
|
|
case OPT_INDEX_OFF:
|
|
config->index = false;
|
|
index_opt = true;
|
|
break;
|
|
|
|
case OPT_UUID_ON:
|
|
config->uuid = true;
|
|
break;
|
|
|
|
case OPT_UUID_OFF:
|
|
config->uuid = false;
|
|
break;
|
|
|
|
case OPT_NFS_EXPORT_ON:
|
|
config->nfs_export = true;
|
|
nfs_export_opt = true;
|
|
break;
|
|
|
|
case OPT_NFS_EXPORT_OFF:
|
|
config->nfs_export = false;
|
|
nfs_export_opt = true;
|
|
break;
|
|
|
|
case OPT_XINO_ON:
|
|
config->xino = OVL_XINO_ON;
|
|
break;
|
|
|
|
case OPT_XINO_OFF:
|
|
config->xino = OVL_XINO_OFF;
|
|
break;
|
|
|
|
case OPT_XINO_AUTO:
|
|
config->xino = OVL_XINO_AUTO;
|
|
break;
|
|
|
|
case OPT_METACOPY_ON:
|
|
config->metacopy = true;
|
|
metacopy_opt = true;
|
|
break;
|
|
|
|
case OPT_METACOPY_OFF:
|
|
config->metacopy = false;
|
|
metacopy_opt = true;
|
|
break;
|
|
|
|
case OPT_VOLATILE:
|
|
config->ovl_volatile = true;
|
|
break;
|
|
|
|
case OPT_USERXATTR:
|
|
config->userxattr = true;
|
|
break;
|
|
|
|
default:
|
|
pr_err("unrecognized mount option \"%s\" or missing value\n",
|
|
p);
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
/* Workdir/index are useless in non-upper mount */
|
|
if (!config->upperdir) {
|
|
if (config->workdir) {
|
|
pr_info("option \"workdir=%s\" is useless in a non-upper mount, ignore\n",
|
|
config->workdir);
|
|
kfree(config->workdir);
|
|
config->workdir = NULL;
|
|
}
|
|
if (config->index && index_opt) {
|
|
pr_info("option \"index=on\" is useless in a non-upper mount, ignore\n");
|
|
index_opt = false;
|
|
}
|
|
config->index = false;
|
|
}
|
|
|
|
if (!config->upperdir && config->ovl_volatile) {
|
|
pr_info("option \"volatile\" is meaningless in a non-upper mount, ignoring it.\n");
|
|
config->ovl_volatile = false;
|
|
}
|
|
|
|
err = ovl_parse_redirect_mode(config, config->redirect_mode);
|
|
if (err)
|
|
return err;
|
|
|
|
/*
|
|
* This is to make the logic below simpler. It doesn't make any other
|
|
* difference, since config->redirect_dir is only used for upper.
|
|
*/
|
|
if (!config->upperdir && config->redirect_follow)
|
|
config->redirect_dir = true;
|
|
|
|
/* Resolve metacopy -> redirect_dir dependency */
|
|
if (config->metacopy && !config->redirect_dir) {
|
|
if (metacopy_opt && redirect_opt) {
|
|
pr_err("conflicting options: metacopy=on,redirect_dir=%s\n",
|
|
config->redirect_mode);
|
|
return -EINVAL;
|
|
}
|
|
if (redirect_opt) {
|
|
/*
|
|
* There was an explicit redirect_dir=... that resulted
|
|
* in this conflict.
|
|
*/
|
|
pr_info("disabling metacopy due to redirect_dir=%s\n",
|
|
config->redirect_mode);
|
|
config->metacopy = false;
|
|
} else {
|
|
/* Automatically enable redirect otherwise. */
|
|
config->redirect_follow = config->redirect_dir = true;
|
|
}
|
|
}
|
|
|
|
/* Resolve nfs_export -> index dependency */
|
|
if (config->nfs_export && !config->index) {
|
|
if (!config->upperdir && config->redirect_follow) {
|
|
pr_info("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n");
|
|
config->nfs_export = false;
|
|
} else if (nfs_export_opt && index_opt) {
|
|
pr_err("conflicting options: nfs_export=on,index=off\n");
|
|
return -EINVAL;
|
|
} else if (index_opt) {
|
|
/*
|
|
* There was an explicit index=off that resulted
|
|
* in this conflict.
|
|
*/
|
|
pr_info("disabling nfs_export due to index=off\n");
|
|
config->nfs_export = false;
|
|
} else {
|
|
/* Automatically enable index otherwise. */
|
|
config->index = true;
|
|
}
|
|
}
|
|
|
|
/* Resolve nfs_export -> !metacopy dependency */
|
|
if (config->nfs_export && config->metacopy) {
|
|
if (nfs_export_opt && metacopy_opt) {
|
|
pr_err("conflicting options: nfs_export=on,metacopy=on\n");
|
|
return -EINVAL;
|
|
}
|
|
if (metacopy_opt) {
|
|
/*
|
|
* There was an explicit metacopy=on that resulted
|
|
* in this conflict.
|
|
*/
|
|
pr_info("disabling nfs_export due to metacopy=on\n");
|
|
config->nfs_export = false;
|
|
} else {
|
|
/*
|
|
* There was an explicit nfs_export=on that resulted
|
|
* in this conflict.
|
|
*/
|
|
pr_info("disabling metacopy due to nfs_export=on\n");
|
|
config->metacopy = false;
|
|
}
|
|
}
|
|
|
|
|
|
/* Resolve userxattr -> !redirect && !metacopy dependency */
|
|
if (config->userxattr) {
|
|
if (config->redirect_follow && redirect_opt) {
|
|
pr_err("conflicting options: userxattr,redirect_dir=%s\n",
|
|
config->redirect_mode);
|
|
return -EINVAL;
|
|
}
|
|
if (config->metacopy && metacopy_opt) {
|
|
pr_err("conflicting options: userxattr,metacopy=on\n");
|
|
return -EINVAL;
|
|
}
|
|
/*
|
|
* Silently disable default setting of redirect and metacopy.
|
|
* This shall be the default in the future as well: these
|
|
* options must be explicitly enabled if used together with
|
|
* userxattr.
|
|
*/
|
|
config->redirect_dir = config->redirect_follow = false;
|
|
config->metacopy = false;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
#define OVL_WORKDIR_NAME "work"
|
|
#define OVL_INDEXDIR_NAME "index"
|
|
|
|
static struct dentry *ovl_workdir_create(struct ovl_fs *ofs,
|
|
const char *name, bool persist)
|
|
{
|
|
struct inode *dir = ofs->workbasedir->d_inode;
|
|
struct vfsmount *mnt = ovl_upper_mnt(ofs);
|
|
struct dentry *work;
|
|
int err;
|
|
bool retried = false;
|
|
|
|
inode_lock_nested(dir, I_MUTEX_PARENT);
|
|
retry:
|
|
work = lookup_one_len(name, ofs->workbasedir, strlen(name));
|
|
|
|
if (!IS_ERR(work)) {
|
|
struct iattr attr = {
|
|
.ia_valid = ATTR_MODE,
|
|
.ia_mode = S_IFDIR | 0,
|
|
};
|
|
|
|
if (work->d_inode) {
|
|
err = -EEXIST;
|
|
if (retried)
|
|
goto out_dput;
|
|
|
|
if (persist)
|
|
goto out_unlock;
|
|
|
|
retried = true;
|
|
err = ovl_workdir_cleanup(dir, mnt, work, 0);
|
|
dput(work);
|
|
if (err == -EINVAL) {
|
|
work = ERR_PTR(err);
|
|
goto out_unlock;
|
|
}
|
|
goto retry;
|
|
}
|
|
|
|
err = ovl_mkdir_real(dir, &work, attr.ia_mode);
|
|
if (err)
|
|
goto out_dput;
|
|
|
|
/* Weird filesystem returning with hashed negative (kernfs)? */
|
|
err = -EINVAL;
|
|
if (d_really_is_negative(work))
|
|
goto out_dput;
|
|
|
|
/*
|
|
* Try to remove POSIX ACL xattrs from workdir. We are good if:
|
|
*
|
|
* a) success (there was a POSIX ACL xattr and was removed)
|
|
* b) -ENODATA (there was no POSIX ACL xattr)
|
|
* c) -EOPNOTSUPP (POSIX ACL xattrs are not supported)
|
|
*
|
|
* There are various other error values that could effectively
|
|
* mean that the xattr doesn't exist (e.g. -ERANGE is returned
|
|
* if the xattr name is too long), but the set of filesystems
|
|
* allowed as upper are limited to "normal" ones, where checking
|
|
* for the above two errors is sufficient.
|
|
*/
|
|
err = vfs_removexattr(&init_user_ns, work,
|
|
XATTR_NAME_POSIX_ACL_DEFAULT);
|
|
if (err && err != -ENODATA && err != -EOPNOTSUPP)
|
|
goto out_dput;
|
|
|
|
err = vfs_removexattr(&init_user_ns, work,
|
|
XATTR_NAME_POSIX_ACL_ACCESS);
|
|
if (err && err != -ENODATA && err != -EOPNOTSUPP)
|
|
goto out_dput;
|
|
|
|
/* Clear any inherited mode bits */
|
|
inode_lock(work->d_inode);
|
|
err = notify_change(&init_user_ns, work, &attr, NULL);
|
|
inode_unlock(work->d_inode);
|
|
if (err)
|
|
goto out_dput;
|
|
} else {
|
|
err = PTR_ERR(work);
|
|
goto out_err;
|
|
}
|
|
out_unlock:
|
|
inode_unlock(dir);
|
|
return work;
|
|
|
|
out_dput:
|
|
dput(work);
|
|
out_err:
|
|
pr_warn("failed to create directory %s/%s (errno: %i); mounting read-only\n",
|
|
ofs->config.workdir, name, -err);
|
|
work = NULL;
|
|
goto out_unlock;
|
|
}
|
|
|
|
static void ovl_unescape(char *s)
|
|
{
|
|
char *d = s;
|
|
|
|
for (;; s++, d++) {
|
|
if (*s == '\\')
|
|
s++;
|
|
*d = *s;
|
|
if (!*s)
|
|
break;
|
|
}
|
|
}
|
|
|
|
static int ovl_mount_dir_noesc(const char *name, struct path *path)
|
|
{
|
|
int err = -EINVAL;
|
|
|
|
if (!*name) {
|
|
pr_err("empty lowerdir\n");
|
|
goto out;
|
|
}
|
|
err = kern_path(name, LOOKUP_FOLLOW, path);
|
|
if (err) {
|
|
pr_err("failed to resolve '%s': %i\n", name, err);
|
|
goto out;
|
|
}
|
|
err = -EINVAL;
|
|
if (ovl_dentry_weird(path->dentry)) {
|
|
pr_err("filesystem on '%s' not supported\n", name);
|
|
goto out_put;
|
|
}
|
|
if (is_idmapped_mnt(path->mnt)) {
|
|
pr_err("idmapped layers are currently not supported\n");
|
|
goto out_put;
|
|
}
|
|
if (!d_is_dir(path->dentry)) {
|
|
pr_err("'%s' not a directory\n", name);
|
|
goto out_put;
|
|
}
|
|
return 0;
|
|
|
|
out_put:
|
|
path_put_init(path);
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static int ovl_mount_dir(const char *name, struct path *path)
|
|
{
|
|
int err = -ENOMEM;
|
|
char *tmp = kstrdup(name, GFP_KERNEL);
|
|
|
|
if (tmp) {
|
|
ovl_unescape(tmp);
|
|
err = ovl_mount_dir_noesc(tmp, path);
|
|
|
|
if (!err && path->dentry->d_flags & DCACHE_OP_REAL) {
|
|
pr_err("filesystem on '%s' not supported as upperdir\n",
|
|
tmp);
|
|
path_put_init(path);
|
|
err = -EINVAL;
|
|
}
|
|
kfree(tmp);
|
|
}
|
|
return err;
|
|
}
|
|
|
|
static int ovl_check_namelen(struct path *path, struct ovl_fs *ofs,
|
|
const char *name)
|
|
{
|
|
struct kstatfs statfs;
|
|
int err = vfs_statfs(path, &statfs);
|
|
|
|
if (err)
|
|
pr_err("statfs failed on '%s'\n", name);
|
|
else
|
|
ofs->namelen = max(ofs->namelen, statfs.f_namelen);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int ovl_lower_dir(const char *name, struct path *path,
|
|
struct ovl_fs *ofs, int *stack_depth)
|
|
{
|
|
int fh_type;
|
|
int err;
|
|
|
|
err = ovl_mount_dir_noesc(name, path);
|
|
if (err)
|
|
return err;
|
|
|
|
err = ovl_check_namelen(path, ofs, name);
|
|
if (err)
|
|
return err;
|
|
|
|
*stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth);
|
|
|
|
/*
|
|
* The inodes index feature and NFS export need to encode and decode
|
|
* file handles, so they require that all layers support them.
|
|
*/
|
|
fh_type = ovl_can_decode_fh(path->dentry->d_sb);
|
|
if ((ofs->config.nfs_export ||
|
|
(ofs->config.index && ofs->config.upperdir)) && !fh_type) {
|
|
ofs->config.index = false;
|
|
ofs->config.nfs_export = false;
|
|
pr_warn("fs on '%s' does not support file handles, falling back to index=off,nfs_export=off.\n",
|
|
name);
|
|
}
|
|
/*
|
|
* Decoding origin file handle is required for persistent st_ino.
|
|
* Without persistent st_ino, xino=auto falls back to xino=off.
|
|
*/
|
|
if (ofs->config.xino == OVL_XINO_AUTO &&
|
|
ofs->config.upperdir && !fh_type) {
|
|
ofs->config.xino = OVL_XINO_OFF;
|
|
pr_warn("fs on '%s' does not support file handles, falling back to xino=off.\n",
|
|
name);
|
|
}
|
|
|
|
/* Check if lower fs has 32bit inode numbers */
|
|
if (fh_type != FILEID_INO32_GEN)
|
|
ofs->xino_mode = -1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Workdir should not be subdir of upperdir and vice versa */
|
|
static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir)
|
|
{
|
|
bool ok = false;
|
|
|
|
if (workdir != upperdir) {
|
|
ok = (lock_rename(workdir, upperdir) == NULL);
|
|
unlock_rename(workdir, upperdir);
|
|
}
|
|
return ok;
|
|
}
|
|
|
|
static unsigned int ovl_split_lowerdirs(char *str)
|
|
{
|
|
unsigned int ctr = 1;
|
|
char *s, *d;
|
|
|
|
for (s = d = str;; s++, d++) {
|
|
if (*s == '\\') {
|
|
s++;
|
|
} else if (*s == ':') {
|
|
*d = '\0';
|
|
ctr++;
|
|
continue;
|
|
}
|
|
*d = *s;
|
|
if (!*s)
|
|
break;
|
|
}
|
|
return ctr;
|
|
}
|
|
|
|
static int __maybe_unused
|
|
ovl_posix_acl_xattr_get(const struct xattr_handler *handler,
|
|
struct dentry *dentry, struct inode *inode,
|
|
const char *name, void *buffer, size_t size)
|
|
{
|
|
return ovl_xattr_get(dentry, inode, handler->name, buffer, size);
|
|
}
|
|
|
|
static int __maybe_unused
|
|
ovl_posix_acl_xattr_set(const struct xattr_handler *handler,
|
|
struct user_namespace *mnt_userns,
|
|
struct dentry *dentry, struct inode *inode,
|
|
const char *name, const void *value,
|
|
size_t size, int flags)
|
|
{
|
|
struct dentry *workdir = ovl_workdir(dentry);
|
|
struct inode *realinode = ovl_inode_real(inode);
|
|
struct posix_acl *acl = NULL;
|
|
int err;
|
|
|
|
/* Check that everything is OK before copy-up */
|
|
if (value) {
|
|
acl = posix_acl_from_xattr(&init_user_ns, value, size);
|
|
if (IS_ERR(acl))
|
|
return PTR_ERR(acl);
|
|
}
|
|
err = -EOPNOTSUPP;
|
|
if (!IS_POSIXACL(d_inode(workdir)))
|
|
goto out_acl_release;
|
|
if (!realinode->i_op->set_acl)
|
|
goto out_acl_release;
|
|
if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) {
|
|
err = acl ? -EACCES : 0;
|
|
goto out_acl_release;
|
|
}
|
|
err = -EPERM;
|
|
if (!inode_owner_or_capable(&init_user_ns, inode))
|
|
goto out_acl_release;
|
|
|
|
posix_acl_release(acl);
|
|
|
|
/*
|
|
* Check if sgid bit needs to be cleared (actual setacl operation will
|
|
* be done with mounter's capabilities and so that won't do it for us).
|
|
*/
|
|
if (unlikely(inode->i_mode & S_ISGID) &&
|
|
handler->flags == ACL_TYPE_ACCESS &&
|
|
!in_group_p(inode->i_gid) &&
|
|
!capable_wrt_inode_uidgid(&init_user_ns, inode, CAP_FSETID)) {
|
|
struct iattr iattr = { .ia_valid = ATTR_KILL_SGID };
|
|
|
|
err = ovl_setattr(&init_user_ns, dentry, &iattr);
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
err = ovl_xattr_set(dentry, inode, handler->name, value, size, flags);
|
|
return err;
|
|
|
|
out_acl_release:
|
|
posix_acl_release(acl);
|
|
return err;
|
|
}
|
|
|
|
static int ovl_own_xattr_get(const struct xattr_handler *handler,
|
|
struct dentry *dentry, struct inode *inode,
|
|
const char *name, void *buffer, size_t size)
|
|
{
|
|
return -EOPNOTSUPP;
|
|
}
|
|
|
|
static int ovl_own_xattr_set(const struct xattr_handler *handler,
|
|
struct user_namespace *mnt_userns,
|
|
struct dentry *dentry, struct inode *inode,
|
|
const char *name, const void *value,
|
|
size_t size, int flags)
|
|
{
|
|
return -EOPNOTSUPP;
|
|
}
|
|
|
|
static int ovl_other_xattr_get(const struct xattr_handler *handler,
|
|
struct dentry *dentry, struct inode *inode,
|
|
const char *name, void *buffer, size_t size)
|
|
{
|
|
return ovl_xattr_get(dentry, inode, name, buffer, size);
|
|
}
|
|
|
|
static int ovl_other_xattr_set(const struct xattr_handler *handler,
|
|
struct user_namespace *mnt_userns,
|
|
struct dentry *dentry, struct inode *inode,
|
|
const char *name, const void *value,
|
|
size_t size, int flags)
|
|
{
|
|
return ovl_xattr_set(dentry, inode, name, value, size, flags);
|
|
}
|
|
|
|
static const struct xattr_handler __maybe_unused
|
|
ovl_posix_acl_access_xattr_handler = {
|
|
.name = XATTR_NAME_POSIX_ACL_ACCESS,
|
|
.flags = ACL_TYPE_ACCESS,
|
|
.get = ovl_posix_acl_xattr_get,
|
|
.set = ovl_posix_acl_xattr_set,
|
|
};
|
|
|
|
static const struct xattr_handler __maybe_unused
|
|
ovl_posix_acl_default_xattr_handler = {
|
|
.name = XATTR_NAME_POSIX_ACL_DEFAULT,
|
|
.flags = ACL_TYPE_DEFAULT,
|
|
.get = ovl_posix_acl_xattr_get,
|
|
.set = ovl_posix_acl_xattr_set,
|
|
};
|
|
|
|
static const struct xattr_handler ovl_own_trusted_xattr_handler = {
|
|
.prefix = OVL_XATTR_TRUSTED_PREFIX,
|
|
.get = ovl_own_xattr_get,
|
|
.set = ovl_own_xattr_set,
|
|
};
|
|
|
|
static const struct xattr_handler ovl_own_user_xattr_handler = {
|
|
.prefix = OVL_XATTR_USER_PREFIX,
|
|
.get = ovl_own_xattr_get,
|
|
.set = ovl_own_xattr_set,
|
|
};
|
|
|
|
static const struct xattr_handler ovl_other_xattr_handler = {
|
|
.prefix = "", /* catch all */
|
|
.get = ovl_other_xattr_get,
|
|
.set = ovl_other_xattr_set,
|
|
};
|
|
|
|
static const struct xattr_handler *ovl_trusted_xattr_handlers[] = {
|
|
#ifdef CONFIG_FS_POSIX_ACL
|
|
&ovl_posix_acl_access_xattr_handler,
|
|
&ovl_posix_acl_default_xattr_handler,
|
|
#endif
|
|
&ovl_own_trusted_xattr_handler,
|
|
&ovl_other_xattr_handler,
|
|
NULL
|
|
};
|
|
|
|
static const struct xattr_handler *ovl_user_xattr_handlers[] = {
|
|
#ifdef CONFIG_FS_POSIX_ACL
|
|
&ovl_posix_acl_access_xattr_handler,
|
|
&ovl_posix_acl_default_xattr_handler,
|
|
#endif
|
|
&ovl_own_user_xattr_handler,
|
|
&ovl_other_xattr_handler,
|
|
NULL
|
|
};
|
|
|
|
static int ovl_setup_trap(struct super_block *sb, struct dentry *dir,
|
|
struct inode **ptrap, const char *name)
|
|
{
|
|
struct inode *trap;
|
|
int err;
|
|
|
|
trap = ovl_get_trap_inode(sb, dir);
|
|
err = PTR_ERR_OR_ZERO(trap);
|
|
if (err) {
|
|
if (err == -ELOOP)
|
|
pr_err("conflicting %s path\n", name);
|
|
return err;
|
|
}
|
|
|
|
*ptrap = trap;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Determine how we treat concurrent use of upperdir/workdir based on the
|
|
* index feature. This is papering over mount leaks of container runtimes,
|
|
* for example, an old overlay mount is leaked and now its upperdir is
|
|
* attempted to be used as a lower layer in a new overlay mount.
|
|
*/
|
|
static int ovl_report_in_use(struct ovl_fs *ofs, const char *name)
|
|
{
|
|
if (ofs->config.index) {
|
|
pr_err("%s is in-use as upperdir/workdir of another mount, mount with '-o index=off' to override exclusive upperdir protection.\n",
|
|
name);
|
|
return -EBUSY;
|
|
} else {
|
|
pr_warn("%s is in-use as upperdir/workdir of another mount, accessing files from both mounts will result in undefined behavior.\n",
|
|
name);
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs,
|
|
struct ovl_layer *upper_layer, struct path *upperpath)
|
|
{
|
|
struct vfsmount *upper_mnt;
|
|
int err;
|
|
|
|
err = ovl_mount_dir(ofs->config.upperdir, upperpath);
|
|
if (err)
|
|
goto out;
|
|
|
|
/* Upperdir path should not be r/o */
|
|
if (__mnt_is_readonly(upperpath->mnt)) {
|
|
pr_err("upper fs is r/o, try multi-lower layers mount\n");
|
|
err = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
err = ovl_check_namelen(upperpath, ofs, ofs->config.upperdir);
|
|
if (err)
|
|
goto out;
|
|
|
|
err = ovl_setup_trap(sb, upperpath->dentry, &upper_layer->trap,
|
|
"upperdir");
|
|
if (err)
|
|
goto out;
|
|
|
|
upper_mnt = clone_private_mount(upperpath);
|
|
err = PTR_ERR(upper_mnt);
|
|
if (IS_ERR(upper_mnt)) {
|
|
pr_err("failed to clone upperpath\n");
|
|
goto out;
|
|
}
|
|
|
|
/* Don't inherit atime flags */
|
|
upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME);
|
|
upper_layer->mnt = upper_mnt;
|
|
upper_layer->idx = 0;
|
|
upper_layer->fsid = 0;
|
|
|
|
/*
|
|
* Inherit SB_NOSEC flag from upperdir.
|
|
*
|
|
* This optimization changes behavior when a security related attribute
|
|
* (suid/sgid/security.*) is changed on an underlying layer. This is
|
|
* okay because we don't yet have guarantees in that case, but it will
|
|
* need careful treatment once we want to honour changes to underlying
|
|
* filesystems.
|
|
*/
|
|
if (upper_mnt->mnt_sb->s_flags & SB_NOSEC)
|
|
sb->s_flags |= SB_NOSEC;
|
|
|
|
if (ovl_inuse_trylock(ovl_upper_mnt(ofs)->mnt_root)) {
|
|
ofs->upperdir_locked = true;
|
|
} else {
|
|
err = ovl_report_in_use(ofs, "upperdir");
|
|
if (err)
|
|
goto out;
|
|
}
|
|
|
|
err = 0;
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* Returns 1 if RENAME_WHITEOUT is supported, 0 if not supported and
|
|
* negative values if error is encountered.
|
|
*/
|
|
static int ovl_check_rename_whiteout(struct dentry *workdir)
|
|
{
|
|
struct inode *dir = d_inode(workdir);
|
|
struct dentry *temp;
|
|
struct dentry *dest;
|
|
struct dentry *whiteout;
|
|
struct name_snapshot name;
|
|
int err;
|
|
|
|
inode_lock_nested(dir, I_MUTEX_PARENT);
|
|
|
|
temp = ovl_create_temp(workdir, OVL_CATTR(S_IFREG | 0));
|
|
err = PTR_ERR(temp);
|
|
if (IS_ERR(temp))
|
|
goto out_unlock;
|
|
|
|
dest = ovl_lookup_temp(workdir);
|
|
err = PTR_ERR(dest);
|
|
if (IS_ERR(dest)) {
|
|
dput(temp);
|
|
goto out_unlock;
|
|
}
|
|
|
|
/* Name is inline and stable - using snapshot as a copy helper */
|
|
take_dentry_name_snapshot(&name, temp);
|
|
err = ovl_do_rename(dir, temp, dir, dest, RENAME_WHITEOUT);
|
|
if (err) {
|
|
if (err == -EINVAL)
|
|
err = 0;
|
|
goto cleanup_temp;
|
|
}
|
|
|
|
whiteout = lookup_one_len(name.name.name, workdir, name.name.len);
|
|
err = PTR_ERR(whiteout);
|
|
if (IS_ERR(whiteout))
|
|
goto cleanup_temp;
|
|
|
|
err = ovl_is_whiteout(whiteout);
|
|
|
|
/* Best effort cleanup of whiteout and temp file */
|
|
if (err)
|
|
ovl_cleanup(dir, whiteout);
|
|
dput(whiteout);
|
|
|
|
cleanup_temp:
|
|
ovl_cleanup(dir, temp);
|
|
release_dentry_name_snapshot(&name);
|
|
dput(temp);
|
|
dput(dest);
|
|
|
|
out_unlock:
|
|
inode_unlock(dir);
|
|
|
|
return err;
|
|
}
|
|
|
|
static struct dentry *ovl_lookup_or_create(struct dentry *parent,
|
|
const char *name, umode_t mode)
|
|
{
|
|
size_t len = strlen(name);
|
|
struct dentry *child;
|
|
|
|
inode_lock_nested(parent->d_inode, I_MUTEX_PARENT);
|
|
child = lookup_one_len(name, parent, len);
|
|
if (!IS_ERR(child) && !child->d_inode)
|
|
child = ovl_create_real(parent->d_inode, child,
|
|
OVL_CATTR(mode));
|
|
inode_unlock(parent->d_inode);
|
|
dput(parent);
|
|
|
|
return child;
|
|
}
|
|
|
|
/*
|
|
* Creates $workdir/work/incompat/volatile/dirty file if it is not already
|
|
* present.
|
|
*/
|
|
static int ovl_create_volatile_dirty(struct ovl_fs *ofs)
|
|
{
|
|
unsigned int ctr;
|
|
struct dentry *d = dget(ofs->workbasedir);
|
|
static const char *const volatile_path[] = {
|
|
OVL_WORKDIR_NAME, "incompat", "volatile", "dirty"
|
|
};
|
|
const char *const *name = volatile_path;
|
|
|
|
for (ctr = ARRAY_SIZE(volatile_path); ctr; ctr--, name++) {
|
|
d = ovl_lookup_or_create(d, *name, ctr > 1 ? S_IFDIR : S_IFREG);
|
|
if (IS_ERR(d))
|
|
return PTR_ERR(d);
|
|
}
|
|
dput(d);
|
|
return 0;
|
|
}
|
|
|
|
static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
|
|
struct path *workpath)
|
|
{
|
|
struct vfsmount *mnt = ovl_upper_mnt(ofs);
|
|
struct dentry *temp, *workdir;
|
|
bool rename_whiteout;
|
|
bool d_type;
|
|
int fh_type;
|
|
int err;
|
|
|
|
err = mnt_want_write(mnt);
|
|
if (err)
|
|
return err;
|
|
|
|
workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false);
|
|
err = PTR_ERR(workdir);
|
|
if (IS_ERR_OR_NULL(workdir))
|
|
goto out;
|
|
|
|
ofs->workdir = workdir;
|
|
|
|
err = ovl_setup_trap(sb, ofs->workdir, &ofs->workdir_trap, "workdir");
|
|
if (err)
|
|
goto out;
|
|
|
|
/*
|
|
* Upper should support d_type, else whiteouts are visible. Given
|
|
* workdir and upper are on same fs, we can do iterate_dir() on
|
|
* workdir. This check requires successful creation of workdir in
|
|
* previous step.
|
|
*/
|
|
err = ovl_check_d_type_supported(workpath);
|
|
if (err < 0)
|
|
goto out;
|
|
|
|
d_type = err;
|
|
if (!d_type)
|
|
pr_warn("upper fs needs to support d_type.\n");
|
|
|
|
/* Check if upper/work fs supports O_TMPFILE */
|
|
temp = ovl_do_tmpfile(ofs->workdir, S_IFREG | 0);
|
|
ofs->tmpfile = !IS_ERR(temp);
|
|
if (ofs->tmpfile)
|
|
dput(temp);
|
|
else
|
|
pr_warn("upper fs does not support tmpfile.\n");
|
|
|
|
|
|
/* Check if upper/work fs supports RENAME_WHITEOUT */
|
|
err = ovl_check_rename_whiteout(ofs->workdir);
|
|
if (err < 0)
|
|
goto out;
|
|
|
|
rename_whiteout = err;
|
|
if (!rename_whiteout)
|
|
pr_warn("upper fs does not support RENAME_WHITEOUT.\n");
|
|
|
|
/*
|
|
* Check if upper/work fs supports (trusted|user).overlay.* xattr
|
|
*/
|
|
err = ovl_do_setxattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE, "0", 1);
|
|
if (err) {
|
|
ofs->noxattr = true;
|
|
if (ofs->config.index || ofs->config.metacopy) {
|
|
ofs->config.index = false;
|
|
ofs->config.metacopy = false;
|
|
pr_warn("upper fs does not support xattr, falling back to index=off,metacopy=off.\n");
|
|
}
|
|
/*
|
|
* xattr support is required for persistent st_ino.
|
|
* Without persistent st_ino, xino=auto falls back to xino=off.
|
|
*/
|
|
if (ofs->config.xino == OVL_XINO_AUTO) {
|
|
ofs->config.xino = OVL_XINO_OFF;
|
|
pr_warn("upper fs does not support xattr, falling back to xino=off.\n");
|
|
}
|
|
err = 0;
|
|
} else {
|
|
ovl_do_removexattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE);
|
|
}
|
|
|
|
/*
|
|
* We allowed sub-optimal upper fs configuration and don't want to break
|
|
* users over kernel upgrade, but we never allowed remote upper fs, so
|
|
* we can enforce strict requirements for remote upper fs.
|
|
*/
|
|
if (ovl_dentry_remote(ofs->workdir) &&
|
|
(!d_type || !rename_whiteout || ofs->noxattr)) {
|
|
pr_err("upper fs missing required features.\n");
|
|
err = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* For volatile mount, create a incompat/volatile/dirty file to keep
|
|
* track of it.
|
|
*/
|
|
if (ofs->config.ovl_volatile) {
|
|
err = ovl_create_volatile_dirty(ofs);
|
|
if (err < 0) {
|
|
pr_err("Failed to create volatile/dirty file.\n");
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
/* Check if upper/work fs supports file handles */
|
|
fh_type = ovl_can_decode_fh(ofs->workdir->d_sb);
|
|
if (ofs->config.index && !fh_type) {
|
|
ofs->config.index = false;
|
|
pr_warn("upper fs does not support file handles, falling back to index=off.\n");
|
|
}
|
|
|
|
/* Check if upper fs has 32bit inode numbers */
|
|
if (fh_type != FILEID_INO32_GEN)
|
|
ofs->xino_mode = -1;
|
|
|
|
/* NFS export of r/w mount depends on index */
|
|
if (ofs->config.nfs_export && !ofs->config.index) {
|
|
pr_warn("NFS export requires \"index=on\", falling back to nfs_export=off.\n");
|
|
ofs->config.nfs_export = false;
|
|
}
|
|
out:
|
|
mnt_drop_write(mnt);
|
|
return err;
|
|
}
|
|
|
|
static int ovl_get_workdir(struct super_block *sb, struct ovl_fs *ofs,
|
|
struct path *upperpath)
|
|
{
|
|
int err;
|
|
struct path workpath = { };
|
|
|
|
err = ovl_mount_dir(ofs->config.workdir, &workpath);
|
|
if (err)
|
|
goto out;
|
|
|
|
err = -EINVAL;
|
|
if (upperpath->mnt != workpath.mnt) {
|
|
pr_err("workdir and upperdir must reside under the same mount\n");
|
|
goto out;
|
|
}
|
|
if (!ovl_workdir_ok(workpath.dentry, upperpath->dentry)) {
|
|
pr_err("workdir and upperdir must be separate subtrees\n");
|
|
goto out;
|
|
}
|
|
|
|
ofs->workbasedir = dget(workpath.dentry);
|
|
|
|
if (ovl_inuse_trylock(ofs->workbasedir)) {
|
|
ofs->workdir_locked = true;
|
|
} else {
|
|
err = ovl_report_in_use(ofs, "workdir");
|
|
if (err)
|
|
goto out;
|
|
}
|
|
|
|
err = ovl_setup_trap(sb, ofs->workbasedir, &ofs->workbasedir_trap,
|
|
"workdir");
|
|
if (err)
|
|
goto out;
|
|
|
|
err = ovl_make_workdir(sb, ofs, &workpath);
|
|
|
|
out:
|
|
path_put(&workpath);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs,
|
|
struct ovl_entry *oe, struct path *upperpath)
|
|
{
|
|
struct vfsmount *mnt = ovl_upper_mnt(ofs);
|
|
struct dentry *indexdir;
|
|
int err;
|
|
|
|
err = mnt_want_write(mnt);
|
|
if (err)
|
|
return err;
|
|
|
|
/* Verify lower root is upper root origin */
|
|
err = ovl_verify_origin(ofs, upperpath->dentry,
|
|
oe->lowerstack[0].dentry, true);
|
|
if (err) {
|
|
pr_err("failed to verify upper root origin\n");
|
|
goto out;
|
|
}
|
|
|
|
/* index dir will act also as workdir */
|
|
iput(ofs->workdir_trap);
|
|
ofs->workdir_trap = NULL;
|
|
dput(ofs->workdir);
|
|
ofs->workdir = NULL;
|
|
indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true);
|
|
if (IS_ERR(indexdir)) {
|
|
err = PTR_ERR(indexdir);
|
|
} else if (indexdir) {
|
|
ofs->indexdir = indexdir;
|
|
ofs->workdir = dget(indexdir);
|
|
|
|
err = ovl_setup_trap(sb, ofs->indexdir, &ofs->indexdir_trap,
|
|
"indexdir");
|
|
if (err)
|
|
goto out;
|
|
|
|
/*
|
|
* Verify upper root is exclusively associated with index dir.
|
|
* Older kernels stored upper fh in ".overlay.origin"
|
|
* xattr. If that xattr exists, verify that it is a match to
|
|
* upper dir file handle. In any case, verify or set xattr
|
|
* ".overlay.upper" to indicate that index may have
|
|
* directory entries.
|
|
*/
|
|
if (ovl_check_origin_xattr(ofs, ofs->indexdir)) {
|
|
err = ovl_verify_set_fh(ofs, ofs->indexdir,
|
|
OVL_XATTR_ORIGIN,
|
|
upperpath->dentry, true, false);
|
|
if (err)
|
|
pr_err("failed to verify index dir 'origin' xattr\n");
|
|
}
|
|
err = ovl_verify_upper(ofs, ofs->indexdir, upperpath->dentry,
|
|
true);
|
|
if (err)
|
|
pr_err("failed to verify index dir 'upper' xattr\n");
|
|
|
|
/* Cleanup bad/stale/orphan index entries */
|
|
if (!err)
|
|
err = ovl_indexdir_cleanup(ofs);
|
|
}
|
|
if (err || !ofs->indexdir)
|
|
pr_warn("try deleting index dir or mounting with '-o index=off' to disable inodes index.\n");
|
|
|
|
out:
|
|
mnt_drop_write(mnt);
|
|
return err;
|
|
}
|
|
|
|
static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid)
|
|
{
|
|
unsigned int i;
|
|
|
|
if (!ofs->config.nfs_export && !ovl_upper_mnt(ofs))
|
|
return true;
|
|
|
|
/*
|
|
* We allow using single lower with null uuid for index and nfs_export
|
|
* for example to support those features with single lower squashfs.
|
|
* To avoid regressions in setups of overlay with re-formatted lower
|
|
* squashfs, do not allow decoding origin with lower null uuid unless
|
|
* user opted-in to one of the new features that require following the
|
|
* lower inode of non-dir upper.
|
|
*/
|
|
if (ovl_allow_offline_changes(ofs) && uuid_is_null(uuid))
|
|
return false;
|
|
|
|
for (i = 0; i < ofs->numfs; i++) {
|
|
/*
|
|
* We use uuid to associate an overlay lower file handle with a
|
|
* lower layer, so we can accept lower fs with null uuid as long
|
|
* as all lower layers with null uuid are on the same fs.
|
|
* if we detect multiple lower fs with the same uuid, we
|
|
* disable lower file handle decoding on all of them.
|
|
*/
|
|
if (ofs->fs[i].is_lower &&
|
|
uuid_equal(&ofs->fs[i].sb->s_uuid, uuid)) {
|
|
ofs->fs[i].bad_uuid = true;
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/* Get a unique fsid for the layer */
|
|
static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path)
|
|
{
|
|
struct super_block *sb = path->mnt->mnt_sb;
|
|
unsigned int i;
|
|
dev_t dev;
|
|
int err;
|
|
bool bad_uuid = false;
|
|
bool warn = false;
|
|
|
|
for (i = 0; i < ofs->numfs; i++) {
|
|
if (ofs->fs[i].sb == sb)
|
|
return i;
|
|
}
|
|
|
|
if (!ovl_lower_uuid_ok(ofs, &sb->s_uuid)) {
|
|
bad_uuid = true;
|
|
if (ofs->config.xino == OVL_XINO_AUTO) {
|
|
ofs->config.xino = OVL_XINO_OFF;
|
|
warn = true;
|
|
}
|
|
if (ofs->config.index || ofs->config.nfs_export) {
|
|
ofs->config.index = false;
|
|
ofs->config.nfs_export = false;
|
|
warn = true;
|
|
}
|
|
if (warn) {
|
|
pr_warn("%s uuid detected in lower fs '%pd2', falling back to xino=%s,index=off,nfs_export=off.\n",
|
|
uuid_is_null(&sb->s_uuid) ? "null" :
|
|
"conflicting",
|
|
path->dentry, ovl_xino_str[ofs->config.xino]);
|
|
}
|
|
}
|
|
|
|
err = get_anon_bdev(&dev);
|
|
if (err) {
|
|
pr_err("failed to get anonymous bdev for lowerpath\n");
|
|
return err;
|
|
}
|
|
|
|
ofs->fs[ofs->numfs].sb = sb;
|
|
ofs->fs[ofs->numfs].pseudo_dev = dev;
|
|
ofs->fs[ofs->numfs].bad_uuid = bad_uuid;
|
|
|
|
return ofs->numfs++;
|
|
}
|
|
|
|
static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs,
|
|
struct path *stack, unsigned int numlower,
|
|
struct ovl_layer *layers)
|
|
{
|
|
int err;
|
|
unsigned int i;
|
|
|
|
err = -ENOMEM;
|
|
ofs->fs = kcalloc(numlower + 1, sizeof(struct ovl_sb), GFP_KERNEL);
|
|
if (ofs->fs == NULL)
|
|
goto out;
|
|
|
|
/* idx/fsid 0 are reserved for upper fs even with lower only overlay */
|
|
ofs->numfs++;
|
|
|
|
/*
|
|
* All lower layers that share the same fs as upper layer, use the same
|
|
* pseudo_dev as upper layer. Allocate fs[0].pseudo_dev even for lower
|
|
* only overlay to simplify ovl_fs_free().
|
|
* is_lower will be set if upper fs is shared with a lower layer.
|
|
*/
|
|
err = get_anon_bdev(&ofs->fs[0].pseudo_dev);
|
|
if (err) {
|
|
pr_err("failed to get anonymous bdev for upper fs\n");
|
|
goto out;
|
|
}
|
|
|
|
if (ovl_upper_mnt(ofs)) {
|
|
ofs->fs[0].sb = ovl_upper_mnt(ofs)->mnt_sb;
|
|
ofs->fs[0].is_lower = false;
|
|
}
|
|
|
|
for (i = 0; i < numlower; i++) {
|
|
struct vfsmount *mnt;
|
|
struct inode *trap;
|
|
int fsid;
|
|
|
|
err = fsid = ovl_get_fsid(ofs, &stack[i]);
|
|
if (err < 0)
|
|
goto out;
|
|
|
|
/*
|
|
* Check if lower root conflicts with this overlay layers before
|
|
* checking if it is in-use as upperdir/workdir of "another"
|
|
* mount, because we do not bother to check in ovl_is_inuse() if
|
|
* the upperdir/workdir is in fact in-use by our
|
|
* upperdir/workdir.
|
|
*/
|
|
err = ovl_setup_trap(sb, stack[i].dentry, &trap, "lowerdir");
|
|
if (err)
|
|
goto out;
|
|
|
|
if (ovl_is_inuse(stack[i].dentry)) {
|
|
err = ovl_report_in_use(ofs, "lowerdir");
|
|
if (err) {
|
|
iput(trap);
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
mnt = clone_private_mount(&stack[i]);
|
|
err = PTR_ERR(mnt);
|
|
if (IS_ERR(mnt)) {
|
|
pr_err("failed to clone lowerpath\n");
|
|
iput(trap);
|
|
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;
|
|
|
|
layers[ofs->numlayer].trap = trap;
|
|
layers[ofs->numlayer].mnt = mnt;
|
|
layers[ofs->numlayer].idx = ofs->numlayer;
|
|
layers[ofs->numlayer].fsid = fsid;
|
|
layers[ofs->numlayer].fs = &ofs->fs[fsid];
|
|
ofs->numlayer++;
|
|
ofs->fs[fsid].is_lower = true;
|
|
}
|
|
|
|
/*
|
|
* When all layers on same fs, overlay can use real inode numbers.
|
|
* With mount option "xino=<on|auto>", mounter declares that there are
|
|
* enough free high bits in underlying fs to hold the unique fsid.
|
|
* If overlayfs does encounter underlying inodes using the high xino
|
|
* bits reserved for fsid, it emits a warning and uses the original
|
|
* inode number or a non persistent inode number allocated from a
|
|
* dedicated range.
|
|
*/
|
|
if (ofs->numfs - !ovl_upper_mnt(ofs) == 1) {
|
|
if (ofs->config.xino == OVL_XINO_ON)
|
|
pr_info("\"xino=on\" is useless with all layers on same fs, ignore.\n");
|
|
ofs->xino_mode = 0;
|
|
} else if (ofs->config.xino == OVL_XINO_OFF) {
|
|
ofs->xino_mode = -1;
|
|
} else if (ofs->xino_mode < 0) {
|
|
/*
|
|
* This is a roundup of number of bits needed for encoding
|
|
* fsid, where fsid 0 is reserved for upper fs (even with
|
|
* lower only overlay) +1 extra bit is reserved for the non
|
|
* persistent inode number range that is used for resolving
|
|
* xino lower bits overflow.
|
|
*/
|
|
BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 30);
|
|
ofs->xino_mode = ilog2(ofs->numfs - 1) + 2;
|
|
}
|
|
|
|
if (ofs->xino_mode > 0) {
|
|
pr_info("\"xino\" feature enabled using %d upper inode bits.\n",
|
|
ofs->xino_mode);
|
|
}
|
|
|
|
err = 0;
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb,
|
|
const char *lower, unsigned int numlower,
|
|
struct ovl_fs *ofs, struct ovl_layer *layers)
|
|
{
|
|
int err;
|
|
struct path *stack = NULL;
|
|
unsigned int i;
|
|
struct ovl_entry *oe;
|
|
|
|
if (!ofs->config.upperdir && numlower == 1) {
|
|
pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n");
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
stack = kcalloc(numlower, sizeof(struct path), GFP_KERNEL);
|
|
if (!stack)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
err = -EINVAL;
|
|
for (i = 0; i < numlower; i++) {
|
|
err = ovl_lower_dir(lower, &stack[i], ofs, &sb->s_stack_depth);
|
|
if (err)
|
|
goto out_err;
|
|
|
|
lower = strchr(lower, '\0') + 1;
|
|
}
|
|
|
|
err = -EINVAL;
|
|
sb->s_stack_depth++;
|
|
if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
|
|
pr_err("maximum fs stacking depth exceeded\n");
|
|
goto out_err;
|
|
}
|
|
|
|
err = ovl_get_layers(sb, ofs, stack, numlower, layers);
|
|
if (err)
|
|
goto out_err;
|
|
|
|
err = -ENOMEM;
|
|
oe = ovl_alloc_entry(numlower);
|
|
if (!oe)
|
|
goto out_err;
|
|
|
|
for (i = 0; i < numlower; i++) {
|
|
oe->lowerstack[i].dentry = dget(stack[i].dentry);
|
|
oe->lowerstack[i].layer = &ofs->layers[i+1];
|
|
}
|
|
|
|
out:
|
|
for (i = 0; i < numlower; i++)
|
|
path_put(&stack[i]);
|
|
kfree(stack);
|
|
|
|
return oe;
|
|
|
|
out_err:
|
|
oe = ERR_PTR(err);
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* Check if this layer root is a descendant of:
|
|
* - another layer of this overlayfs instance
|
|
* - upper/work dir of any overlayfs instance
|
|
*/
|
|
static int ovl_check_layer(struct super_block *sb, struct ovl_fs *ofs,
|
|
struct dentry *dentry, const char *name,
|
|
bool is_lower)
|
|
{
|
|
struct dentry *next = dentry, *parent;
|
|
int err = 0;
|
|
|
|
if (!dentry)
|
|
return 0;
|
|
|
|
parent = dget_parent(next);
|
|
|
|
/* Walk back ancestors to root (inclusive) looking for traps */
|
|
while (!err && parent != next) {
|
|
if (is_lower && ovl_lookup_trap_inode(sb, parent)) {
|
|
err = -ELOOP;
|
|
pr_err("overlapping %s path\n", name);
|
|
} else if (ovl_is_inuse(parent)) {
|
|
err = ovl_report_in_use(ofs, name);
|
|
}
|
|
next = parent;
|
|
parent = dget_parent(next);
|
|
dput(next);
|
|
}
|
|
|
|
dput(parent);
|
|
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* Check if any of the layers or work dirs overlap.
|
|
*/
|
|
static int ovl_check_overlapping_layers(struct super_block *sb,
|
|
struct ovl_fs *ofs)
|
|
{
|
|
int i, err;
|
|
|
|
if (ovl_upper_mnt(ofs)) {
|
|
err = ovl_check_layer(sb, ofs, ovl_upper_mnt(ofs)->mnt_root,
|
|
"upperdir", false);
|
|
if (err)
|
|
return err;
|
|
|
|
/*
|
|
* Checking workbasedir avoids hitting ovl_is_inuse(parent) of
|
|
* this instance and covers overlapping work and index dirs,
|
|
* unless work or index dir have been moved since created inside
|
|
* workbasedir. In that case, we already have their traps in
|
|
* inode cache and we will catch that case on lookup.
|
|
*/
|
|
err = ovl_check_layer(sb, ofs, ofs->workbasedir, "workdir",
|
|
false);
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
for (i = 1; i < ofs->numlayer; i++) {
|
|
err = ovl_check_layer(sb, ofs,
|
|
ofs->layers[i].mnt->mnt_root,
|
|
"lowerdir", true);
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct dentry *ovl_get_root(struct super_block *sb,
|
|
struct dentry *upperdentry,
|
|
struct ovl_entry *oe)
|
|
{
|
|
struct dentry *root;
|
|
struct ovl_path *lowerpath = &oe->lowerstack[0];
|
|
unsigned long ino = d_inode(lowerpath->dentry)->i_ino;
|
|
int fsid = lowerpath->layer->fsid;
|
|
struct ovl_inode_params oip = {
|
|
.upperdentry = upperdentry,
|
|
.lowerpath = lowerpath,
|
|
};
|
|
|
|
root = d_make_root(ovl_new_inode(sb, S_IFDIR, 0));
|
|
if (!root)
|
|
return NULL;
|
|
|
|
root->d_fsdata = oe;
|
|
|
|
if (upperdentry) {
|
|
/* Root inode uses upper st_ino/i_ino */
|
|
ino = d_inode(upperdentry)->i_ino;
|
|
fsid = 0;
|
|
ovl_dentry_set_upper_alias(root);
|
|
if (ovl_is_impuredir(sb, upperdentry))
|
|
ovl_set_flag(OVL_IMPURE, d_inode(root));
|
|
}
|
|
|
|
/* Root is always merge -> can have whiteouts */
|
|
ovl_set_flag(OVL_WHITEOUTS, d_inode(root));
|
|
ovl_dentry_set_flag(OVL_E_CONNECTED, root);
|
|
ovl_set_upperdata(d_inode(root));
|
|
ovl_inode_init(d_inode(root), &oip, ino, fsid);
|
|
ovl_dentry_update_reval(root, upperdentry, DCACHE_OP_WEAK_REVALIDATE);
|
|
|
|
return root;
|
|
}
|
|
|
|
static int ovl_fill_super(struct super_block *sb, void *data, int silent)
|
|
{
|
|
struct path upperpath = { };
|
|
struct dentry *root_dentry;
|
|
struct ovl_entry *oe;
|
|
struct ovl_fs *ofs;
|
|
struct ovl_layer *layers;
|
|
struct cred *cred;
|
|
char *splitlower = NULL;
|
|
unsigned int numlower;
|
|
int err;
|
|
|
|
err = -EIO;
|
|
if (WARN_ON(sb->s_user_ns != current_user_ns()))
|
|
goto out;
|
|
|
|
sb->s_d_op = &ovl_dentry_operations;
|
|
|
|
err = -ENOMEM;
|
|
ofs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL);
|
|
if (!ofs)
|
|
goto out;
|
|
|
|
err = -ENOMEM;
|
|
ofs->creator_cred = cred = prepare_creds();
|
|
if (!cred)
|
|
goto out_err;
|
|
|
|
/* Is there a reason anyone would want not to share whiteouts? */
|
|
ofs->share_whiteout = true;
|
|
|
|
ofs->config.index = ovl_index_def;
|
|
ofs->config.uuid = true;
|
|
ofs->config.nfs_export = ovl_nfs_export_def;
|
|
ofs->config.xino = ovl_xino_def();
|
|
ofs->config.metacopy = ovl_metacopy_def;
|
|
err = ovl_parse_opt((char *) data, &ofs->config);
|
|
if (err)
|
|
goto out_err;
|
|
|
|
err = -EINVAL;
|
|
if (!ofs->config.lowerdir) {
|
|
if (!silent)
|
|
pr_err("missing 'lowerdir'\n");
|
|
goto out_err;
|
|
}
|
|
|
|
err = -ENOMEM;
|
|
splitlower = kstrdup(ofs->config.lowerdir, GFP_KERNEL);
|
|
if (!splitlower)
|
|
goto out_err;
|
|
|
|
err = -EINVAL;
|
|
numlower = ovl_split_lowerdirs(splitlower);
|
|
if (numlower > OVL_MAX_STACK) {
|
|
pr_err("too many lower directories, limit is %d\n",
|
|
OVL_MAX_STACK);
|
|
goto out_err;
|
|
}
|
|
|
|
err = -ENOMEM;
|
|
layers = kcalloc(numlower + 1, sizeof(struct ovl_layer), GFP_KERNEL);
|
|
if (!layers)
|
|
goto out_err;
|
|
|
|
ofs->layers = layers;
|
|
/* Layer 0 is reserved for upper even if there's no upper */
|
|
ofs->numlayer = 1;
|
|
|
|
sb->s_stack_depth = 0;
|
|
sb->s_maxbytes = MAX_LFS_FILESIZE;
|
|
atomic_long_set(&ofs->last_ino, 1);
|
|
/* Assume underlaying fs uses 32bit inodes unless proven otherwise */
|
|
if (ofs->config.xino != OVL_XINO_OFF) {
|
|
ofs->xino_mode = BITS_PER_LONG - 32;
|
|
if (!ofs->xino_mode) {
|
|
pr_warn("xino not supported on 32bit kernel, falling back to xino=off.\n");
|
|
ofs->config.xino = OVL_XINO_OFF;
|
|
}
|
|
}
|
|
|
|
/* alloc/destroy_inode needed for setting up traps in inode cache */
|
|
sb->s_op = &ovl_super_operations;
|
|
|
|
if (ofs->config.upperdir) {
|
|
struct super_block *upper_sb;
|
|
|
|
err = -EINVAL;
|
|
if (!ofs->config.workdir) {
|
|
pr_err("missing 'workdir'\n");
|
|
goto out_err;
|
|
}
|
|
|
|
err = ovl_get_upper(sb, ofs, &layers[0], &upperpath);
|
|
if (err)
|
|
goto out_err;
|
|
|
|
upper_sb = ovl_upper_mnt(ofs)->mnt_sb;
|
|
if (!ovl_should_sync(ofs)) {
|
|
ofs->errseq = errseq_sample(&upper_sb->s_wb_err);
|
|
if (errseq_check(&upper_sb->s_wb_err, ofs->errseq)) {
|
|
err = -EIO;
|
|
pr_err("Cannot mount volatile when upperdir has an unseen error. Sync upperdir fs to clear state.\n");
|
|
goto out_err;
|
|
}
|
|
}
|
|
|
|
err = ovl_get_workdir(sb, ofs, &upperpath);
|
|
if (err)
|
|
goto out_err;
|
|
|
|
if (!ofs->workdir)
|
|
sb->s_flags |= SB_RDONLY;
|
|
|
|
sb->s_stack_depth = upper_sb->s_stack_depth;
|
|
sb->s_time_gran = upper_sb->s_time_gran;
|
|
}
|
|
oe = ovl_get_lowerstack(sb, splitlower, numlower, ofs, layers);
|
|
err = PTR_ERR(oe);
|
|
if (IS_ERR(oe))
|
|
goto out_err;
|
|
|
|
/* If the upper fs is nonexistent, we mark overlayfs r/o too */
|
|
if (!ovl_upper_mnt(ofs))
|
|
sb->s_flags |= SB_RDONLY;
|
|
|
|
if (!ofs->config.uuid && ofs->numfs > 1) {
|
|
pr_warn("The uuid=off requires a single fs for lower and upper, falling back to uuid=on.\n");
|
|
ofs->config.uuid = true;
|
|
}
|
|
|
|
if (!ovl_force_readonly(ofs) && ofs->config.index) {
|
|
err = ovl_get_indexdir(sb, ofs, oe, &upperpath);
|
|
if (err)
|
|
goto out_free_oe;
|
|
|
|
/* Force r/o mount with no index dir */
|
|
if (!ofs->indexdir)
|
|
sb->s_flags |= SB_RDONLY;
|
|
}
|
|
|
|
err = ovl_check_overlapping_layers(sb, ofs);
|
|
if (err)
|
|
goto out_free_oe;
|
|
|
|
/* Show index=off in /proc/mounts for forced r/o mount */
|
|
if (!ofs->indexdir) {
|
|
ofs->config.index = false;
|
|
if (ovl_upper_mnt(ofs) && ofs->config.nfs_export) {
|
|
pr_warn("NFS export requires an index dir, falling back to nfs_export=off.\n");
|
|
ofs->config.nfs_export = false;
|
|
}
|
|
}
|
|
|
|
if (ofs->config.metacopy && ofs->config.nfs_export) {
|
|
pr_warn("NFS export is not supported with metadata only copy up, falling back to nfs_export=off.\n");
|
|
ofs->config.nfs_export = false;
|
|
}
|
|
|
|
if (ofs->config.nfs_export)
|
|
sb->s_export_op = &ovl_export_operations;
|
|
|
|
/* Never override disk quota limits or use reserved space */
|
|
cap_lower(cred->cap_effective, CAP_SYS_RESOURCE);
|
|
|
|
sb->s_magic = OVERLAYFS_SUPER_MAGIC;
|
|
sb->s_xattr = ofs->config.userxattr ? ovl_user_xattr_handlers :
|
|
ovl_trusted_xattr_handlers;
|
|
sb->s_fs_info = ofs;
|
|
sb->s_flags |= SB_POSIXACL;
|
|
sb->s_iflags |= SB_I_SKIP_SYNC;
|
|
|
|
err = -ENOMEM;
|
|
root_dentry = ovl_get_root(sb, upperpath.dentry, oe);
|
|
if (!root_dentry)
|
|
goto out_free_oe;
|
|
|
|
mntput(upperpath.mnt);
|
|
kfree(splitlower);
|
|
|
|
sb->s_root = root_dentry;
|
|
|
|
return 0;
|
|
|
|
out_free_oe:
|
|
ovl_entry_stack_free(oe);
|
|
kfree(oe);
|
|
out_err:
|
|
kfree(splitlower);
|
|
path_put(&upperpath);
|
|
ovl_free_fs(ofs);
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags,
|
|
const char *dev_name, void *raw_data)
|
|
{
|
|
return mount_nodev(fs_type, flags, raw_data, ovl_fill_super);
|
|
}
|
|
|
|
static struct file_system_type ovl_fs_type = {
|
|
.owner = THIS_MODULE,
|
|
.name = "overlay",
|
|
.fs_flags = FS_USERNS_MOUNT,
|
|
.mount = ovl_mount,
|
|
.kill_sb = kill_anon_super,
|
|
};
|
|
MODULE_ALIAS_FS("overlay");
|
|
|
|
static void ovl_inode_init_once(void *foo)
|
|
{
|
|
struct ovl_inode *oi = foo;
|
|
|
|
inode_init_once(&oi->vfs_inode);
|
|
}
|
|
|
|
static int __init ovl_init(void)
|
|
{
|
|
int err;
|
|
|
|
ovl_inode_cachep = kmem_cache_create("ovl_inode",
|
|
sizeof(struct ovl_inode), 0,
|
|
(SLAB_RECLAIM_ACCOUNT|
|
|
SLAB_MEM_SPREAD|SLAB_ACCOUNT),
|
|
ovl_inode_init_once);
|
|
if (ovl_inode_cachep == NULL)
|
|
return -ENOMEM;
|
|
|
|
err = ovl_aio_request_cache_init();
|
|
if (!err) {
|
|
err = register_filesystem(&ovl_fs_type);
|
|
if (!err)
|
|
return 0;
|
|
|
|
ovl_aio_request_cache_destroy();
|
|
}
|
|
kmem_cache_destroy(ovl_inode_cachep);
|
|
|
|
return err;
|
|
}
|
|
|
|
static void __exit ovl_exit(void)
|
|
{
|
|
unregister_filesystem(&ovl_fs_type);
|
|
|
|
/*
|
|
* Make sure all delayed rcu free inodes are flushed before we
|
|
* destroy cache.
|
|
*/
|
|
rcu_barrier();
|
|
kmem_cache_destroy(ovl_inode_cachep);
|
|
ovl_aio_request_cache_destroy();
|
|
}
|
|
|
|
module_init(ovl_init);
|
|
module_exit(ovl_exit);
|