297 lines
6.4 KiB
C
297 lines
6.4 KiB
C
/*
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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 "overlayfs.h"
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#include "ovl_entry.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 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 (oe->__upperdentry) {
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type = __OVL_PATH_UPPER;
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/*
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* Non-dir dentry can hold lower dentry from previous
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* location.
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*/
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if (oe->numlower && d_is_dir(dentry))
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type |= __OVL_PATH_MERGE;
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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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struct ovl_entry *oe = dentry->d_fsdata;
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path->mnt = ofs->upper_mnt;
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path->dentry = ovl_upperdentry_dereference(oe);
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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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*path = oe->numlower ? oe->lowerstack[0] : (struct path) { NULL, NULL };
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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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struct ovl_entry *oe = dentry->d_fsdata;
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return ovl_upperdentry_dereference(oe);
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}
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static struct dentry *__ovl_dentry_lower(struct ovl_entry *oe)
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{
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return oe->numlower ? oe->lowerstack[0].dentry : NULL;
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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 __ovl_dentry_lower(oe);
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}
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struct dentry *ovl_dentry_real(struct dentry *dentry)
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{
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struct ovl_entry *oe = dentry->d_fsdata;
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struct dentry *realdentry;
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realdentry = ovl_upperdentry_dereference(oe);
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if (!realdentry)
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realdentry = __ovl_dentry_lower(oe);
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return realdentry;
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}
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struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
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{
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struct ovl_entry *oe = dentry->d_fsdata;
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return oe->cache;
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}
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void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache)
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{
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struct ovl_entry *oe = dentry->d_fsdata;
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oe->cache = cache;
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}
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bool ovl_dentry_is_opaque(struct dentry *dentry)
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{
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struct ovl_entry *oe = dentry->d_fsdata;
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return oe->opaque;
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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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struct ovl_entry *oe = dentry->d_fsdata;
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oe->opaque = true;
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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;
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}
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void ovl_clear_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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ofs->config.redirect_dir = false;
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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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struct ovl_entry *oe = dentry->d_fsdata;
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return oe->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_entry *oe = dentry->d_fsdata;
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kfree(oe->redirect);
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oe->redirect = redirect;
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}
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void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
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{
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struct ovl_entry *oe = dentry->d_fsdata;
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WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode));
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WARN_ON(oe->__upperdentry);
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/*
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* Make sure upperdentry is consistent before making it visible to
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* ovl_upperdentry_dereference().
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*/
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smp_wmb();
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oe->__upperdentry = upperdentry;
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}
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void ovl_inode_init(struct inode *inode, struct inode *realinode, bool is_upper)
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{
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WRITE_ONCE(inode->i_private, (unsigned long) realinode |
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(is_upper ? OVL_ISUPPER_MASK : 0));
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}
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void ovl_inode_update(struct inode *inode, struct inode *upperinode)
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{
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WARN_ON(!upperinode);
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WARN_ON(!inode_unhashed(inode));
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WRITE_ONCE(inode->i_private,
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(unsigned long) upperinode | OVL_ISUPPER_MASK);
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if (!S_ISDIR(upperinode->i_mode))
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__insert_inode_hash(inode, (unsigned long) upperinode);
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}
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void ovl_dentry_version_inc(struct dentry *dentry)
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{
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struct ovl_entry *oe = dentry->d_fsdata;
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WARN_ON(!inode_is_locked(dentry->d_inode));
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oe->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 ovl_entry *oe = dentry->d_fsdata;
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WARN_ON(!inode_is_locked(dentry->d_inode));
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return oe->version;
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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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int ovl_copy_up_start(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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struct ovl_entry *oe = dentry->d_fsdata;
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int err;
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spin_lock(&ofs->copyup_wq.lock);
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err = wait_event_interruptible_locked(ofs->copyup_wq, !oe->copying);
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if (!err) {
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if (oe->__upperdentry)
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err = 1; /* Already copied up */
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else
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oe->copying = true;
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}
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spin_unlock(&ofs->copyup_wq.lock);
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return err;
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}
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void ovl_copy_up_end(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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struct ovl_entry *oe = dentry->d_fsdata;
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spin_lock(&ofs->copyup_wq.lock);
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oe->copying = false;
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wake_up_locked(&ofs->copyup_wq);
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spin_unlock(&ofs->copyup_wq.lock);
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}
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