From 23fa18eaa71266feff7ba8d83022d9e1cc83c65a Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Fri, 10 May 2024 07:42:03 +0000
Subject: [PATCH] disable pwm7
---
kernel/fs/overlayfs/dir.c | 182 ++++++++++++++++++++++++++++++---------------
1 files changed, 122 insertions(+), 60 deletions(-)
diff --git a/kernel/fs/overlayfs/dir.c b/kernel/fs/overlayfs/dir.c
index d03749b..82e8ab2 100644
--- a/kernel/fs/overlayfs/dir.c
+++ b/kernel/fs/overlayfs/dir.c
@@ -1,10 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
*
* Copyright (C) 2011 Novell Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
*/
#include <linux/fs.h>
@@ -21,7 +18,7 @@
static unsigned short ovl_redirect_max = 256;
module_param_named(redirect_max, ovl_redirect_max, ushort, 0644);
-MODULE_PARM_DESC(ovl_redirect_max,
+MODULE_PARM_DESC(redirect_max,
"Maximum length of absolute redirect xattr value");
static int ovl_set_redirect(struct dentry *dentry, bool samedir);
@@ -38,14 +35,14 @@
dput(wdentry);
if (err) {
- pr_err("overlayfs: cleanup of '%pd2' failed (%i)\n",
+ pr_err("cleanup of '%pd2' failed (%i)\n",
wdentry, err);
}
return err;
}
-static struct dentry *ovl_lookup_temp(struct dentry *workdir)
+struct dentry *ovl_lookup_temp(struct dentry *workdir)
{
struct dentry *temp;
char name[20];
@@ -56,7 +53,7 @@
temp = lookup_one_len(name, workdir, strlen(name));
if (!IS_ERR(temp) && temp->d_inode) {
- pr_err("overlayfs: workdir/%s already exists\n", name);
+ pr_err("workdir/%s already exists\n", name);
dput(temp);
temp = ERR_PTR(-EIO);
}
@@ -65,35 +62,59 @@
}
/* caller holds i_mutex on workdir */
-static struct dentry *ovl_whiteout(struct dentry *workdir)
+static struct dentry *ovl_whiteout(struct ovl_fs *ofs)
{
int err;
struct dentry *whiteout;
+ struct dentry *workdir = ofs->workdir;
struct inode *wdir = workdir->d_inode;
- whiteout = ovl_lookup_temp(workdir);
- if (IS_ERR(whiteout))
- return whiteout;
+ if (!ofs->whiteout) {
+ whiteout = ovl_lookup_temp(workdir);
+ if (IS_ERR(whiteout))
+ goto out;
- err = ovl_do_whiteout(wdir, whiteout);
- if (err) {
- dput(whiteout);
- whiteout = ERR_PTR(err);
+ err = ovl_do_whiteout(wdir, whiteout);
+ if (err) {
+ dput(whiteout);
+ whiteout = ERR_PTR(err);
+ goto out;
+ }
+ ofs->whiteout = whiteout;
}
+ if (ofs->share_whiteout) {
+ whiteout = ovl_lookup_temp(workdir);
+ if (IS_ERR(whiteout))
+ goto out;
+
+ err = ovl_do_link(ofs->whiteout, wdir, whiteout);
+ if (!err)
+ goto out;
+
+ if (err != -EMLINK) {
+ pr_warn("Failed to link whiteout - disabling whiteout inode sharing(nlink=%u, err=%i)\n",
+ ofs->whiteout->d_inode->i_nlink, err);
+ ofs->share_whiteout = false;
+ }
+ dput(whiteout);
+ }
+ whiteout = ofs->whiteout;
+ ofs->whiteout = NULL;
+out:
return whiteout;
}
/* Caller must hold i_mutex on both workdir and dir */
-int ovl_cleanup_and_whiteout(struct dentry *workdir, struct inode *dir,
+int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir,
struct dentry *dentry)
{
- struct inode *wdir = workdir->d_inode;
+ struct inode *wdir = ofs->workdir->d_inode;
struct dentry *whiteout;
int err;
int flags = 0;
- whiteout = ovl_whiteout(workdir);
+ whiteout = ovl_whiteout(ofs);
err = PTR_ERR(whiteout);
if (IS_ERR(whiteout))
return err;
@@ -136,7 +157,7 @@
d = lookup_one_len(dentry->d_name.name, dentry->d_parent,
dentry->d_name.len);
if (IS_ERR(d)) {
- pr_warn("overlayfs: failed lookup after mkdir (%pd2, err=%i).\n",
+ pr_warn("failed lookup after mkdir (%pd2, err=%i).\n",
dentry, err);
return PTR_ERR(d);
}
@@ -245,6 +266,8 @@
ovl_dir_modified(dentry->d_parent, false);
ovl_dentry_set_upper_alias(dentry);
+ ovl_dentry_init_reval(dentry, newdentry);
+
if (!hardlink) {
/*
* ovl_obtain_alias() can be called after ovl_create_real()
@@ -261,6 +284,8 @@
inode = ovl_get_inode(dentry->d_sb, &oip);
if (IS_ERR(inode))
return PTR_ERR(inode);
+ if (inode == oip.newinode)
+ ovl_set_flag(OVL_UPPERDATA, inode);
} else {
WARN_ON(ovl_inode_real(inode) != d_inode(newdentry));
dput(newdentry);
@@ -269,7 +294,7 @@
d_instantiate(dentry, inode);
if (inode != oip.newinode) {
- pr_warn_ratelimited("overlayfs: newly created inode found in cache (%pd2)\n",
+ pr_warn_ratelimited("newly created inode found in cache (%pd2)\n",
dentry);
}
@@ -367,7 +392,7 @@
if (IS_ERR(opaquedir))
goto out_unlock;
- err = ovl_copy_xattr(upper, opaquedir);
+ err = ovl_copy_xattr(dentry->d_sb, upper, opaquedir);
if (err)
goto out_cleanup;
@@ -413,13 +438,12 @@
if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !acl)
return 0;
- size = posix_acl_to_xattr(NULL, acl, NULL, 0);
+ size = posix_acl_xattr_size(acl->a_count);
buffer = kmalloc(size, GFP_KERNEL);
if (!buffer)
return -ENOMEM;
- size = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
- err = size;
+ err = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
if (err < 0)
goto out_free;
@@ -561,31 +585,45 @@
goto out_revert_creds;
}
- err = -ENOMEM;
- override_cred = prepare_creds();
- if (override_cred) {
+ if (!attr->hardlink) {
+ err = -ENOMEM;
+ override_cred = prepare_creds();
+ if (!override_cred)
+ goto out_revert_creds;
+ /*
+ * In the creation cases(create, mkdir, mknod, symlink),
+ * ovl should transfer current's fs{u,g}id to underlying
+ * fs. Because underlying fs want to initialize its new
+ * inode owner using current's fs{u,g}id. And in this
+ * case, the @inode is a new inode that is initialized
+ * in inode_init_owner() to current's fs{u,g}id. So use
+ * the inode's i_{u,g}id to override the cred's fs{u,g}id.
+ *
+ * But in the other hardlink case, ovl_link() does not
+ * create a new inode, so just use the ovl mounter's
+ * fs{u,g}id.
+ */
override_cred->fsuid = inode->i_uid;
override_cred->fsgid = inode->i_gid;
- if (!attr->hardlink) {
- err = security_dentry_create_files_as(dentry,
- attr->mode, &dentry->d_name,
- old_cred ? old_cred : current_cred(),
- override_cred);
- if (err) {
- put_cred(override_cred);
- goto out_revert_creds;
- }
+ err = security_dentry_create_files_as(dentry,
+ attr->mode, &dentry->d_name,
+ old_cred ? old_cred : current_cred(),
+ override_cred);
+ if (err) {
+ put_cred(override_cred);
+ goto out_revert_creds;
}
hold_cred = override_creds(override_cred);
put_cred(override_cred);
-
- if (!ovl_dentry_is_whiteout(dentry))
- err = ovl_create_upper(dentry, inode, attr);
- else
- err = ovl_create_over_whiteout(dentry, inode, attr);
}
+
+ if (!ovl_dentry_is_whiteout(dentry))
+ err = ovl_create_upper(dentry, inode, attr);
+ else
+ err = ovl_create_over_whiteout(dentry, inode, attr);
+
out_revert_creds:
- ovl_revert_creds(old_cred ?: hold_cred);
+ ovl_revert_creds(dentry->d_sb, old_cred ?: hold_cred);
if (old_cred && hold_cred)
put_cred(hold_cred);
return err;
@@ -663,7 +701,7 @@
old_cred = ovl_override_creds(dentry->d_sb);
err = ovl_set_redirect(dentry, false);
- ovl_revert_creds(old_cred);
+ ovl_revert_creds(dentry->d_sb, old_cred);
return err;
}
@@ -672,7 +710,6 @@
struct dentry *new)
{
int err;
- bool locked = false;
struct inode *inode;
err = ovl_want_write(old);
@@ -693,7 +730,7 @@
goto out_drop_write;
}
- err = ovl_nlink_start(old, &locked);
+ err = ovl_nlink_start(old);
if (err)
goto out_drop_write;
@@ -706,7 +743,7 @@
if (err)
iput(inode);
- ovl_nlink_end(old, locked);
+ ovl_nlink_end(old);
out_drop_write:
ovl_drop_write(old);
out:
@@ -721,6 +758,7 @@
static int ovl_remove_and_whiteout(struct dentry *dentry,
struct list_head *list)
{
+ struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
struct dentry *workdir = ovl_workdir(dentry);
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
struct dentry *upper;
@@ -754,7 +792,7 @@
goto out_dput_upper;
}
- err = ovl_cleanup_and_whiteout(workdir, d_inode(upperdir), upper);
+ err = ovl_cleanup_and_whiteout(ofs, d_inode(upperdir), upper);
if (err)
goto out_d_drop;
@@ -828,10 +866,31 @@
!ovl_test_flag(OVL_WHITEOUTS, d_inode(dentry));
}
+static void ovl_drop_nlink(struct dentry *dentry)
+{
+ struct inode *inode = d_inode(dentry);
+ struct dentry *alias;
+
+ /* Try to find another, hashed alias */
+ spin_lock(&inode->i_lock);
+ hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
+ if (alias != dentry && !d_unhashed(alias))
+ break;
+ }
+ spin_unlock(&inode->i_lock);
+
+ /*
+ * Changes to underlying layers may cause i_nlink to lose sync with
+ * reality. In this case prevent the link count from going to zero
+ * prematurely.
+ */
+ if (inode->i_nlink > !!alias)
+ drop_nlink(inode);
+}
+
static int ovl_do_remove(struct dentry *dentry, bool is_dir)
{
int err;
- bool locked = false;
const struct cred *old_cred;
struct dentry *upperdentry;
bool lower_positive = ovl_lower_positive(dentry);
@@ -852,7 +911,7 @@
if (err)
goto out_drop_write;
- err = ovl_nlink_start(dentry, &locked);
+ err = ovl_nlink_start(dentry);
if (err)
goto out_drop_write;
@@ -861,14 +920,14 @@
err = ovl_remove_upper(dentry, is_dir, &list);
else
err = ovl_remove_and_whiteout(dentry, &list);
- ovl_revert_creds(old_cred);
+ ovl_revert_creds(dentry->d_sb, old_cred);
if (!err) {
if (is_dir)
clear_nlink(dentry->d_inode);
else
- drop_nlink(dentry->d_inode);
+ ovl_drop_nlink(dentry);
}
- ovl_nlink_end(dentry, locked);
+ ovl_nlink_end(dentry);
/*
* Copy ctime
@@ -1019,7 +1078,7 @@
spin_unlock(&dentry->d_lock);
} else {
kfree(redirect);
- pr_warn_ratelimited("overlayfs: failed to set redirect (%i)\n",
+ pr_warn_ratelimited("failed to set redirect (%i)\n",
err);
/* Fall back to userspace copy-up */
err = -EXDEV;
@@ -1032,7 +1091,6 @@
unsigned int flags)
{
int err;
- bool locked = false;
struct dentry *old_upperdir;
struct dentry *new_upperdir;
struct dentry *olddentry;
@@ -1041,6 +1099,7 @@
bool old_opaque;
bool new_opaque;
bool cleanup_whiteout = false;
+ bool update_nlink = false;
bool overwrite = !(flags & RENAME_EXCHANGE);
bool is_dir = d_is_dir(old);
bool new_is_dir = d_is_dir(new);
@@ -1098,10 +1157,12 @@
err = ovl_copy_up(new);
if (err)
goto out_drop_write;
- } else {
- err = ovl_nlink_start(new, &locked);
+ } else if (d_inode(new)) {
+ err = ovl_nlink_start(new);
if (err)
goto out_drop_write;
+
+ update_nlink = true;
}
old_cred = ovl_override_creds(old->d_sb);
@@ -1213,7 +1274,7 @@
if (new_is_dir)
clear_nlink(d_inode(new));
else
- drop_nlink(d_inode(new));
+ ovl_drop_nlink(new);
}
ovl_dir_modified(old->d_parent, ovl_type_origin(old) ||
@@ -1233,8 +1294,9 @@
out_unlock:
unlock_rename(new_upperdir, old_upperdir);
out_revert_creds:
- ovl_revert_creds(old_cred);
- ovl_nlink_end(new, locked);
+ ovl_revert_creds(old->d_sb, old_cred);
+ if (update_nlink)
+ ovl_nlink_end(new);
out_drop_write:
ovl_drop_write(old);
out:
--
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