Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 1122 insertions, 0 deletions

diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
new file mode 100644
index 000000000..923d66d13
--- /dev/null
+++ b/fs/overlayfs/util.c
@@ -0,0 +1,1122 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2011 Novell Inc.
+ * Copyright (C) 2016 Red Hat, Inc.
+ */
+
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/slab.h>
+#include <linux/cred.h>
+#include <linux/xattr.h>
+#include <linux/exportfs.h>
+#include <linux/fileattr.h>
+#include <linux/uuid.h>
+#include <linux/namei.h>
+#include <linux/ratelimit.h>
+#include "overlayfs.h"
+
+int ovl_want_write(struct dentry *dentry)
+{
+	struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+	return mnt_want_write(ovl_upper_mnt(ofs));
+}
+
+void ovl_drop_write(struct dentry *dentry)
+{
+	struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+	mnt_drop_write(ovl_upper_mnt(ofs));
+}
+
+struct dentry *ovl_workdir(struct dentry *dentry)
+{
+	struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+	return ofs->workdir;
+}
+
+const struct cred *ovl_override_creds(struct super_block *sb)
+{
+	struct ovl_fs *ofs = sb->s_fs_info;
+
+	return override_creds(ofs->creator_cred);
+}
+
+/*
+ * Check if underlying fs supports file handles and try to determine encoding
+ * type, in order to deduce maximum inode number used by fs.
+ *
+ * Return 0 if file handles are not supported.
+ * Return 1 (FILEID_INO32_GEN) if fs uses the default 32bit inode encoding.
+ * Return -1 if fs uses a non default encoding with unknown inode size.
+ */
+int ovl_can_decode_fh(struct super_block *sb)
+{
+	if (!capable(CAP_DAC_READ_SEARCH))
+		return 0;
+
+	if (!sb->s_export_op || !sb->s_export_op->fh_to_dentry)
+		return 0;
+
+	return sb->s_export_op->encode_fh ? -1 : FILEID_INO32_GEN;
+}
+
+struct dentry *ovl_indexdir(struct super_block *sb)
+{
+	struct ovl_fs *ofs = sb->s_fs_info;
+
+	return ofs->indexdir;
+}
+
+/* Index all files on copy up. For now only enabled for NFS export */
+bool ovl_index_all(struct super_block *sb)
+{
+	struct ovl_fs *ofs = sb->s_fs_info;
+
+	return ofs->config.nfs_export && ofs->config.index;
+}
+
+/* Verify lower origin on lookup. For now only enabled for NFS export */
+bool ovl_verify_lower(struct super_block *sb)
+{
+	struct ovl_fs *ofs = sb->s_fs_info;
+
+	return ofs->config.nfs_export && ofs->config.index;
+}
+
+struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
+{
+	size_t size = offsetof(struct ovl_entry, lowerstack[numlower]);
+	struct ovl_entry *oe = kzalloc(size, GFP_KERNEL);
+
+	if (oe)
+		oe->numlower = numlower;
+
+	return oe;
+}
+
+bool ovl_dentry_remote(struct dentry *dentry)
+{
+	return dentry->d_flags &
+		(DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE);
+}
+
+void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *upperdentry,
+			     unsigned int mask)
+{
+	struct ovl_entry *oe = OVL_E(dentry);
+	unsigned int i, flags = 0;
+
+	if (upperdentry)
+		flags |= upperdentry->d_flags;
+	for (i = 0; i < oe->numlower; i++)
+		flags |= oe->lowerstack[i].dentry->d_flags;
+
+	spin_lock(&dentry->d_lock);
+	dentry->d_flags &= ~mask;
+	dentry->d_flags |= flags & mask;
+	spin_unlock(&dentry->d_lock);
+}
+
+bool ovl_dentry_weird(struct dentry *dentry)
+{
+	return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT |
+				  DCACHE_MANAGE_TRANSIT |
+				  DCACHE_OP_HASH |
+				  DCACHE_OP_COMPARE);
+}
+
+enum ovl_path_type ovl_path_type(struct dentry *dentry)
+{
+	struct ovl_entry *oe = dentry->d_fsdata;
+	enum ovl_path_type type = 0;
+
+	if (ovl_dentry_upper(dentry)) {
+		type = __OVL_PATH_UPPER;
+
+		/*
+		 * Non-dir dentry can hold lower dentry of its copy up origin.
+		 */
+		if (oe->numlower) {
+			if (ovl_test_flag(OVL_CONST_INO, d_inode(dentry)))
+				type |= __OVL_PATH_ORIGIN;
+			if (d_is_dir(dentry) ||
+			    !ovl_has_upperdata(d_inode(dentry)))
+				type |= __OVL_PATH_MERGE;
+		}
+	} else {
+		if (oe->numlower > 1)
+			type |= __OVL_PATH_MERGE;
+	}
+	return type;
+}
+
+void ovl_path_upper(struct dentry *dentry, struct path *path)
+{
+	struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+
+	path->mnt = ovl_upper_mnt(ofs);
+	path->dentry = ovl_dentry_upper(dentry);
+}
+
+void ovl_path_lower(struct dentry *dentry, struct path *path)
+{
+	struct ovl_entry *oe = dentry->d_fsdata;
+
+	if (oe->numlower) {
+		path->mnt = oe->lowerstack[0].layer->mnt;
+		path->dentry = oe->lowerstack[0].dentry;
+	} else {
+		*path = (struct path) { };
+	}
+}
+
+void ovl_path_lowerdata(struct dentry *dentry, struct path *path)
+{
+	struct ovl_entry *oe = dentry->d_fsdata;
+
+	if (oe->numlower) {
+		path->mnt = oe->lowerstack[oe->numlower - 1].layer->mnt;
+		path->dentry = oe->lowerstack[oe->numlower - 1].dentry;
+	} else {
+		*path = (struct path) { };
+	}
+}
+
+enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
+{
+	enum ovl_path_type type = ovl_path_type(dentry);
+
+	if (!OVL_TYPE_UPPER(type))
+		ovl_path_lower(dentry, path);
+	else
+		ovl_path_upper(dentry, path);
+
+	return type;
+}
+
+enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path)
+{
+	enum ovl_path_type type = ovl_path_type(dentry);
+
+	WARN_ON_ONCE(d_is_dir(dentry));
+
+	if (!OVL_TYPE_UPPER(type) || OVL_TYPE_MERGE(type))
+		ovl_path_lowerdata(dentry, path);
+	else
+		ovl_path_upper(dentry, path);
+
+	return type;
+}
+
+struct dentry *ovl_dentry_upper(struct dentry *dentry)
+{
+	return ovl_upperdentry_dereference(OVL_I(d_inode(dentry)));
+}
+
+struct dentry *ovl_dentry_lower(struct dentry *dentry)
+{
+	struct ovl_entry *oe = dentry->d_fsdata;
+
+	return oe->numlower ? oe->lowerstack[0].dentry : NULL;
+}
+
+const struct ovl_layer *ovl_layer_lower(struct dentry *dentry)
+{
+	struct ovl_entry *oe = dentry->d_fsdata;
+
+	return oe->numlower ? oe->lowerstack[0].layer : NULL;
+}
+
+/*
+ * ovl_dentry_lower() could return either a data dentry or metacopy dentry
+ * depending on what is stored in lowerstack[0]. At times we need to find
+ * lower dentry which has data (and not metacopy dentry). This helper
+ * returns the lower data dentry.
+ */
+struct dentry *ovl_dentry_lowerdata(struct dentry *dentry)
+{
+	struct ovl_entry *oe = dentry->d_fsdata;
+
+	return oe->numlower ? oe->lowerstack[oe->numlower - 1].dentry : NULL;
+}
+
+struct dentry *ovl_dentry_real(struct dentry *dentry)
+{
+	return ovl_dentry_upper(dentry) ?: ovl_dentry_lower(dentry);
+}
+
+struct dentry *ovl_i_dentry_upper(struct inode *inode)
+{
+	return ovl_upperdentry_dereference(OVL_I(inode));
+}
+
+void ovl_i_path_real(struct inode *inode, struct path *path)
+{
+	path->dentry = ovl_i_dentry_upper(inode);
+	if (!path->dentry) {
+		path->dentry = OVL_I(inode)->lowerpath.dentry;
+		path->mnt = OVL_I(inode)->lowerpath.layer->mnt;
+	} else {
+		path->mnt = ovl_upper_mnt(OVL_FS(inode->i_sb));
+	}
+}
+
+struct inode *ovl_inode_upper(struct inode *inode)
+{
+	struct dentry *upperdentry = ovl_i_dentry_upper(inode);
+
+	return upperdentry ? d_inode(upperdentry) : NULL;
+}
+
+struct inode *ovl_inode_lower(struct inode *inode)
+{
+	struct dentry *lowerdentry = OVL_I(inode)->lowerpath.dentry;
+
+	return lowerdentry ? d_inode(lowerdentry) : NULL;
+}
+
+struct inode *ovl_inode_real(struct inode *inode)
+{
+	return ovl_inode_upper(inode) ?: ovl_inode_lower(inode);
+}
+
+/* Return inode which contains lower data. Do not return metacopy */
+struct inode *ovl_inode_lowerdata(struct inode *inode)
+{
+	if (WARN_ON(!S_ISREG(inode->i_mode)))
+		return NULL;
+
+	return OVL_I(inode)->lowerdata ?: ovl_inode_lower(inode);
+}
+
+/* Return real inode which contains data. Does not return metacopy inode */
+struct inode *ovl_inode_realdata(struct inode *inode)
+{
+	struct inode *upperinode;
+
+	upperinode = ovl_inode_upper(inode);
+	if (upperinode && ovl_has_upperdata(inode))
+		return upperinode;
+
+	return ovl_inode_lowerdata(inode);
+}
+
+struct ovl_dir_cache *ovl_dir_cache(struct inode *inode)
+{
+	return OVL_I(inode)->cache;
+}
+
+void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache)
+{
+	OVL_I(inode)->cache = cache;
+}
+
+void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry)
+{
+	set_bit(flag, &OVL_E(dentry)->flags);
+}
+
+void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry)
+{
+	clear_bit(flag, &OVL_E(dentry)->flags);
+}
+
+bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry)
+{
+	return test_bit(flag, &OVL_E(dentry)->flags);
+}
+
+bool ovl_dentry_is_opaque(struct dentry *dentry)
+{
+	return ovl_dentry_test_flag(OVL_E_OPAQUE, dentry);
+}
+
+bool ovl_dentry_is_whiteout(struct dentry *dentry)
+{
+	return !dentry->d_inode && ovl_dentry_is_opaque(dentry);
+}
+
+void ovl_dentry_set_opaque(struct dentry *dentry)
+{
+	ovl_dentry_set_flag(OVL_E_OPAQUE, dentry);
+}
+
+/*
+ * For hard links and decoded file handles, it's possible for ovl_dentry_upper()
+ * to return positive, while there's no actual upper alias for the inode.
+ * Copy up code needs to know about the existence of the upper alias, so it
+ * can't use ovl_dentry_upper().
+ */
+bool ovl_dentry_has_upper_alias(struct dentry *dentry)
+{
+	return ovl_dentry_test_flag(OVL_E_UPPER_ALIAS, dentry);
+}
+
+void ovl_dentry_set_upper_alias(struct dentry *dentry)
+{
+	ovl_dentry_set_flag(OVL_E_UPPER_ALIAS, dentry);
+}
+
+static bool ovl_should_check_upperdata(struct inode *inode)
+{
+	if (!S_ISREG(inode->i_mode))
+		return false;
+
+	if (!ovl_inode_lower(inode))
+		return false;
+
+	return true;
+}
+
+bool ovl_has_upperdata(struct inode *inode)
+{
+	if (!ovl_should_check_upperdata(inode))
+		return true;
+
+	if (!ovl_test_flag(OVL_UPPERDATA, inode))
+		return false;
+	/*
+	 * Pairs with smp_wmb() in ovl_set_upperdata(). Main user of
+	 * ovl_has_upperdata() is ovl_copy_up_meta_inode_data(). Make sure
+	 * if setting of OVL_UPPERDATA is visible, then effects of writes
+	 * before that are visible too.
+	 */
+	smp_rmb();
+	return true;
+}
+
+void ovl_set_upperdata(struct inode *inode)
+{
+	/*
+	 * Pairs with smp_rmb() in ovl_has_upperdata(). Make sure
+	 * if OVL_UPPERDATA flag is visible, then effects of write operations
+	 * before it are visible as well.
+	 */
+	smp_wmb();
+	ovl_set_flag(OVL_UPPERDATA, inode);
+}
+
+/* Caller should hold ovl_inode->lock */
+bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags)
+{
+	if (!ovl_open_flags_need_copy_up(flags))
+		return false;
+
+	return !ovl_test_flag(OVL_UPPERDATA, d_inode(dentry));
+}
+
+bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags)
+{
+	if (!ovl_open_flags_need_copy_up(flags))
+		return false;
+
+	return !ovl_has_upperdata(d_inode(dentry));
+}
+
+bool ovl_redirect_dir(struct super_block *sb)
+{
+	struct ovl_fs *ofs = sb->s_fs_info;
+
+	return ofs->config.redirect_dir && !ofs->noxattr;
+}
+
+const char *ovl_dentry_get_redirect(struct dentry *dentry)
+{
+	return OVL_I(d_inode(dentry))->redirect;
+}
+
+void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect)
+{
+	struct ovl_inode *oi = OVL_I(d_inode(dentry));
+
+	kfree(oi->redirect);
+	oi->redirect = redirect;
+}
+
+void ovl_inode_update(struct inode *inode, struct dentry *upperdentry)
+{
+	struct inode *upperinode = d_inode(upperdentry);
+
+	WARN_ON(OVL_I(inode)->__upperdentry);
+
+	/*
+	 * Make sure upperdentry is consistent before making it visible
+	 */
+	smp_wmb();
+	OVL_I(inode)->__upperdentry = upperdentry;
+	if (inode_unhashed(inode)) {
+		inode->i_private = upperinode;
+		__insert_inode_hash(inode, (unsigned long) upperinode);
+	}
+}
+
+static void ovl_dir_version_inc(struct dentry *dentry, bool impurity)
+{
+	struct inode *inode = d_inode(dentry);
+
+	WARN_ON(!inode_is_locked(inode));
+	WARN_ON(!d_is_dir(dentry));
+	/*
+	 * Version is used by readdir code to keep cache consistent.
+	 * For merge dirs (or dirs with origin) all changes need to be noted.
+	 * For non-merge dirs, cache contains only impure entries (i.e. ones
+	 * which have been copied up and have origins), so only need to note
+	 * changes to impure entries.
+	 */
+	if (!ovl_dir_is_real(inode) || impurity)
+		OVL_I(inode)->version++;
+}
+
+void ovl_dir_modified(struct dentry *dentry, bool impurity)
+{
+	/* Copy mtime/ctime */
+	ovl_copyattr(d_inode(dentry));
+
+	ovl_dir_version_inc(dentry, impurity);
+}
+
+u64 ovl_inode_version_get(struct inode *inode)
+{
+	WARN_ON(!inode_is_locked(inode));
+	return OVL_I(inode)->version;
+}
+
+bool ovl_is_whiteout(struct dentry *dentry)
+{
+	struct inode *inode = dentry->d_inode;
+
+	return inode && IS_WHITEOUT(inode);
+}
+
+struct file *ovl_path_open(const struct path *path, int flags)
+{
+	struct inode *inode = d_inode(path->dentry);
+	struct mnt_idmap *real_idmap = mnt_idmap(path->mnt);
+	int err, acc_mode;
+
+	if (flags & ~(O_ACCMODE | O_LARGEFILE))
+		BUG();
+
+	switch (flags & O_ACCMODE) {
+	case O_RDONLY:
+		acc_mode = MAY_READ;
+		break;
+	case O_WRONLY:
+		acc_mode = MAY_WRITE;
+		break;
+	default:
+		BUG();
+	}
+
+	err = inode_permission(real_idmap, inode, acc_mode | MAY_OPEN);
+	if (err)
+		return ERR_PTR(err);
+
+	/* O_NOATIME is an optimization, don't fail if not permitted */
+	if (inode_owner_or_capable(real_idmap, inode))
+		flags |= O_NOATIME;
+
+	return dentry_open(path, flags, current_cred());
+}
+
+/* Caller should hold ovl_inode->lock */
+static bool ovl_already_copied_up_locked(struct dentry *dentry, int flags)
+{
+	bool disconnected = dentry->d_flags & DCACHE_DISCONNECTED;
+
+	if (ovl_dentry_upper(dentry) &&
+	    (ovl_dentry_has_upper_alias(dentry) || disconnected) &&
+	    !ovl_dentry_needs_data_copy_up_locked(dentry, flags))
+		return true;
+
+	return false;
+}
+
+bool ovl_already_copied_up(struct dentry *dentry, int flags)
+{
+	bool disconnected = dentry->d_flags & DCACHE_DISCONNECTED;
+
+	/*
+	 * Check if copy-up has happened as well as for upper alias (in
+	 * case of hard links) is there.
+	 *
+	 * Both checks are lockless:
+	 *  - false negatives: will recheck under oi->lock
+	 *  - false positives:
+	 *    + ovl_dentry_upper() uses memory barriers to ensure the
+	 *      upper dentry is up-to-date
+	 *    + ovl_dentry_has_upper_alias() relies on locking of
+	 *      upper parent i_rwsem to prevent reordering copy-up
+	 *      with rename.
+	 */
+	if (ovl_dentry_upper(dentry) &&
+	    (ovl_dentry_has_upper_alias(dentry) || disconnected) &&
+	    !ovl_dentry_needs_data_copy_up(dentry, flags))
+		return true;
+
+	return false;
+}
+
+int ovl_copy_up_start(struct dentry *dentry, int flags)
+{
+	struct inode *inode = d_inode(dentry);
+	int err;
+
+	err = ovl_inode_lock_interruptible(inode);
+	if (!err && ovl_already_copied_up_locked(dentry, flags)) {
+		err = 1; /* Already copied up */
+		ovl_inode_unlock(inode);
+	}
+
+	return err;
+}
+
+void ovl_copy_up_end(struct dentry *dentry)
+{
+	ovl_inode_unlock(d_inode(dentry));
+}
+
+bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, const struct path *path)
+{
+	int res;
+
+	res = ovl_path_getxattr(ofs, path, OVL_XATTR_ORIGIN, NULL, 0);
+
+	/* Zero size value means "copied up but origin unknown" */
+	if (res >= 0)
+		return true;
+
+	return false;
+}
+
+bool ovl_path_check_dir_xattr(struct ovl_fs *ofs, const struct path *path,
+			       enum ovl_xattr ox)
+{
+	int res;
+	char val;
+
+	if (!d_is_dir(path->dentry))
+		return false;
+
+	res = ovl_path_getxattr(ofs, path, ox, &val, 1);
+	if (res == 1 && val == 'y')
+		return true;
+
+	return false;
+}
+
+#define OVL_XATTR_OPAQUE_POSTFIX	"opaque"
+#define OVL_XATTR_REDIRECT_POSTFIX	"redirect"
+#define OVL_XATTR_ORIGIN_POSTFIX	"origin"
+#define OVL_XATTR_IMPURE_POSTFIX	"impure"
+#define OVL_XATTR_NLINK_POSTFIX		"nlink"
+#define OVL_XATTR_UPPER_POSTFIX		"upper"
+#define OVL_XATTR_METACOPY_POSTFIX	"metacopy"
+#define OVL_XATTR_PROTATTR_POSTFIX	"protattr"
+
+#define OVL_XATTR_TAB_ENTRY(x) \
+	[x] = { [false] = OVL_XATTR_TRUSTED_PREFIX x ## _POSTFIX, \
+		[true] = OVL_XATTR_USER_PREFIX x ## _POSTFIX }
+
+const char *const ovl_xattr_table[][2] = {
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_OPAQUE),
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_REDIRECT),
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_ORIGIN),
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_IMPURE),
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_NLINK),
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_UPPER),
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_METACOPY),
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_PROTATTR),
+};
+
+int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry,
+		       enum ovl_xattr ox, const void *value, size_t size,
+		       int xerr)
+{
+	int err;
+
+	if (ofs->noxattr)
+		return xerr;
+
+	err = ovl_setxattr(ofs, upperdentry, ox, value, size);
+
+	if (err == -EOPNOTSUPP) {
+		pr_warn("cannot set %s xattr on upper\n", ovl_xattr(ofs, ox));
+		ofs->noxattr = true;
+		return xerr;
+	}
+
+	return err;
+}
+
+int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry)
+{
+	struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
+	int err;
+
+	if (ovl_test_flag(OVL_IMPURE, d_inode(dentry)))
+		return 0;
+
+	/*
+	 * Do not fail when upper doesn't support xattrs.
+	 * Upper inodes won't have origin nor redirect xattr anyway.
+	 */
+	err = ovl_check_setxattr(ofs, upperdentry, OVL_XATTR_IMPURE, "y", 1, 0);
+	if (!err)
+		ovl_set_flag(OVL_IMPURE, d_inode(dentry));
+
+	return err;
+}
+
+
+#define OVL_PROTATTR_MAX 32 /* Reserved for future flags */
+
+void ovl_check_protattr(struct inode *inode, struct dentry *upper)
+{
+	struct ovl_fs *ofs = OVL_FS(inode->i_sb);
+	u32 iflags = inode->i_flags & OVL_PROT_I_FLAGS_MASK;
+	char buf[OVL_PROTATTR_MAX+1];
+	int res, n;
+
+	res = ovl_getxattr_upper(ofs, upper, OVL_XATTR_PROTATTR, buf,
+				 OVL_PROTATTR_MAX);
+	if (res < 0)
+		return;
+
+	/*
+	 * Initialize inode flags from overlay.protattr xattr and upper inode
+	 * flags.  If upper inode has those fileattr flags set (i.e. from old
+	 * kernel), we do not clear them on ovl_get_inode(), but we will clear
+	 * them on next fileattr_set().
+	 */
+	for (n = 0; n < res; n++) {
+		if (buf[n] == 'a')
+			iflags |= S_APPEND;
+		else if (buf[n] == 'i')
+			iflags |= S_IMMUTABLE;
+		else
+			break;
+	}
+
+	if (!res || n < res) {
+		pr_warn_ratelimited("incompatible overlay.protattr format (%pd2, len=%d)\n",
+				    upper, res);
+	} else {
+		inode_set_flags(inode, iflags, OVL_PROT_I_FLAGS_MASK);
+	}
+}
+
+int ovl_set_protattr(struct inode *inode, struct dentry *upper,
+		      struct fileattr *fa)
+{
+	struct ovl_fs *ofs = OVL_FS(inode->i_sb);
+	char buf[OVL_PROTATTR_MAX];
+	int len = 0, err = 0;
+	u32 iflags = 0;
+
+	BUILD_BUG_ON(HWEIGHT32(OVL_PROT_FS_FLAGS_MASK) > OVL_PROTATTR_MAX);
+
+	if (fa->flags & FS_APPEND_FL) {
+		buf[len++] = 'a';
+		iflags |= S_APPEND;
+	}
+	if (fa->flags & FS_IMMUTABLE_FL) {
+		buf[len++] = 'i';
+		iflags |= S_IMMUTABLE;
+	}
+
+	/*
+	 * Do not allow to set protection flags when upper doesn't support
+	 * xattrs, because we do not set those fileattr flags on upper inode.
+	 * Remove xattr if it exist and all protection flags are cleared.
+	 */
+	if (len) {
+		err = ovl_check_setxattr(ofs, upper, OVL_XATTR_PROTATTR,
+					 buf, len, -EPERM);
+	} else if (inode->i_flags & OVL_PROT_I_FLAGS_MASK) {
+		err = ovl_removexattr(ofs, upper, OVL_XATTR_PROTATTR);
+		if (err == -EOPNOTSUPP || err == -ENODATA)
+			err = 0;
+	}
+	if (err)
+		return err;
+
+	inode_set_flags(inode, iflags, OVL_PROT_I_FLAGS_MASK);
+
+	/* Mask out the fileattr flags that should not be set in upper inode */
+	fa->flags &= ~OVL_PROT_FS_FLAGS_MASK;
+	fa->fsx_xflags &= ~OVL_PROT_FSX_FLAGS_MASK;
+
+	return 0;
+}
+
+/**
+ * Caller must hold a reference to inode to prevent it from being freed while
+ * it is marked inuse.
+ */
+bool ovl_inuse_trylock(struct dentry *dentry)
+{
+	struct inode *inode = d_inode(dentry);
+	bool locked = false;
+
+	spin_lock(&inode->i_lock);
+	if (!(inode->i_state & I_OVL_INUSE)) {
+		inode->i_state |= I_OVL_INUSE;
+		locked = true;
+	}
+	spin_unlock(&inode->i_lock);
+
+	return locked;
+}
+
+void ovl_inuse_unlock(struct dentry *dentry)
+{
+	if (dentry) {
+		struct inode *inode = d_inode(dentry);
+
+		spin_lock(&inode->i_lock);
+		WARN_ON(!(inode->i_state & I_OVL_INUSE));
+		inode->i_state &= ~I_OVL_INUSE;
+		spin_unlock(&inode->i_lock);
+	}
+}
+
+bool ovl_is_inuse(struct dentry *dentry)
+{
+	struct inode *inode = d_inode(dentry);
+	bool inuse;
+
+	spin_lock(&inode->i_lock);
+	inuse = (inode->i_state & I_OVL_INUSE);
+	spin_unlock(&inode->i_lock);
+
+	return inuse;
+}
+
+/*
+ * Does this overlay dentry need to be indexed on copy up?
+ */
+bool ovl_need_index(struct dentry *dentry)
+{
+	struct dentry *lower = ovl_dentry_lower(dentry);
+
+	if (!lower || !ovl_indexdir(dentry->d_sb))
+		return false;
+
+	/* Index all files for NFS export and consistency verification */
+	if (ovl_index_all(dentry->d_sb))
+		return true;
+
+	/* Index only lower hardlinks on copy up */
+	if (!d_is_dir(lower) && d_inode(lower)->i_nlink > 1)
+		return true;
+
+	return false;
+}
+
+/* Caller must hold OVL_I(inode)->lock */
+static void ovl_cleanup_index(struct dentry *dentry)
+{
+	struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
+	struct dentry *indexdir = ovl_indexdir(dentry->d_sb);
+	struct inode *dir = indexdir->d_inode;
+	struct dentry *lowerdentry = ovl_dentry_lower(dentry);
+	struct dentry *upperdentry = ovl_dentry_upper(dentry);
+	struct dentry *index = NULL;
+	struct inode *inode;
+	struct qstr name = { };
+	int err;
+
+	err = ovl_get_index_name(ofs, lowerdentry, &name);
+	if (err)
+		goto fail;
+
+	inode = d_inode(upperdentry);
+	if (!S_ISDIR(inode->i_mode) && inode->i_nlink != 1) {
+		pr_warn_ratelimited("cleanup linked index (%pd2, ino=%lu, nlink=%u)\n",
+				    upperdentry, inode->i_ino, inode->i_nlink);
+		/*
+		 * We either have a bug with persistent union nlink or a lower
+		 * hardlink was added while overlay is mounted. Adding a lower
+		 * hardlink and then unlinking all overlay hardlinks would drop
+		 * overlay nlink to zero before all upper inodes are unlinked.
+		 * As a safety measure, when that situation is detected, set
+		 * the overlay nlink to the index inode nlink minus one for the
+		 * index entry itself.
+		 */
+		set_nlink(d_inode(dentry), inode->i_nlink - 1);
+		ovl_set_nlink_upper(dentry);
+		goto out;
+	}
+
+	inode_lock_nested(dir, I_MUTEX_PARENT);
+	index = ovl_lookup_upper(ofs, name.name, indexdir, name.len);
+	err = PTR_ERR(index);
+	if (IS_ERR(index)) {
+		index = NULL;
+	} else if (ovl_index_all(dentry->d_sb)) {
+		/* Whiteout orphan index to block future open by handle */
+		err = ovl_cleanup_and_whiteout(OVL_FS(dentry->d_sb),
+					       dir, index);
+	} else {
+		/* Cleanup orphan index entries */
+		err = ovl_cleanup(ofs, dir, index);
+	}
+
+	inode_unlock(dir);
+	if (err)
+		goto fail;
+
+out:
+	kfree(name.name);
+	dput(index);
+	return;
+
+fail:
+	pr_err("cleanup index of '%pd2' failed (%i)\n", dentry, err);
+	goto out;
+}
+
+/*
+ * Operations that change overlay inode and upper inode nlink need to be
+ * synchronized with copy up for persistent nlink accounting.
+ */
+int ovl_nlink_start(struct dentry *dentry)
+{
+	struct inode *inode = d_inode(dentry);
+	const struct cred *old_cred;
+	int err;
+
+	if (WARN_ON(!inode))
+		return -ENOENT;
+
+	/*
+	 * With inodes index is enabled, we store the union overlay nlink
+	 * in an xattr on the index inode. When whiting out an indexed lower,
+	 * we need to decrement the overlay persistent nlink, but before the
+	 * first copy up, we have no upper index inode to store the xattr.
+	 *
+	 * As a workaround, before whiteout/rename over an indexed lower,
+	 * copy up to create the upper index. Creating the upper index will
+	 * initialize the overlay nlink, so it could be dropped if unlink
+	 * or rename succeeds.
+	 *
+	 * TODO: implement metadata only index copy up when called with
+	 *       ovl_copy_up_flags(dentry, O_PATH).
+	 */
+	if (ovl_need_index(dentry) && !ovl_dentry_has_upper_alias(dentry)) {
+		err = ovl_copy_up(dentry);
+		if (err)
+			return err;
+	}
+
+	err = ovl_inode_lock_interruptible(inode);
+	if (err)
+		return err;
+
+	if (d_is_dir(dentry) || !ovl_test_flag(OVL_INDEX, inode))
+		goto out;
+
+	old_cred = ovl_override_creds(dentry->d_sb);
+	/*
+	 * The overlay inode nlink should be incremented/decremented IFF the
+	 * upper operation succeeds, along with nlink change of upper inode.
+	 * Therefore, before link/unlink/rename, we store the union nlink
+	 * value relative to the upper inode nlink in an upper inode xattr.
+	 */
+	err = ovl_set_nlink_upper(dentry);
+	revert_creds(old_cred);
+
+out:
+	if (err)
+		ovl_inode_unlock(inode);
+
+	return err;
+}
+
+void ovl_nlink_end(struct dentry *dentry)
+{
+	struct inode *inode = d_inode(dentry);
+
+	if (ovl_test_flag(OVL_INDEX, inode) && inode->i_nlink == 0) {
+		const struct cred *old_cred;
+
+		old_cred = ovl_override_creds(dentry->d_sb);
+		ovl_cleanup_index(dentry);
+		revert_creds(old_cred);
+	}
+
+	ovl_inode_unlock(inode);
+}
+
+int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir)
+{
+	/* Workdir should not be the same as upperdir */
+	if (workdir == upperdir)
+		goto err;
+
+	/* Workdir should not be subdir of upperdir and vice versa */
+	if (lock_rename(workdir, upperdir) != NULL)
+		goto err_unlock;
+
+	return 0;
+
+err_unlock:
+	unlock_rename(workdir, upperdir);
+err:
+	pr_err("failed to lock workdir+upperdir\n");
+	return -EIO;
+}
+
+/* err < 0, 0 if no metacopy xattr, 1 if metacopy xattr found */
+int ovl_check_metacopy_xattr(struct ovl_fs *ofs, const struct path *path)
+{
+	int res;
+
+	/* Only regular files can have metacopy xattr */
+	if (!S_ISREG(d_inode(path->dentry)->i_mode))
+		return 0;
+
+	res = ovl_path_getxattr(ofs, path, OVL_XATTR_METACOPY, NULL, 0);
+	if (res < 0) {
+		if (res == -ENODATA || res == -EOPNOTSUPP)
+			return 0;
+		/*
+		 * getxattr on user.* may fail with EACCES in case there's no
+		 * read permission on the inode.  Not much we can do, other than
+		 * tell the caller that this is not a metacopy inode.
+		 */
+		if (ofs->config.userxattr && res == -EACCES)
+			return 0;
+		goto out;
+	}
+
+	return 1;
+out:
+	pr_warn_ratelimited("failed to get metacopy (%i)\n", res);
+	return res;
+}
+
+bool ovl_is_metacopy_dentry(struct dentry *dentry)
+{
+	struct ovl_entry *oe = dentry->d_fsdata;
+
+	if (!d_is_reg(dentry))
+		return false;
+
+	if (ovl_dentry_upper(dentry)) {
+		if (!ovl_has_upperdata(d_inode(dentry)))
+			return true;
+		return false;
+	}
+
+	return (oe->numlower > 1);
+}
+
+char *ovl_get_redirect_xattr(struct ovl_fs *ofs, const struct path *path, int padding)
+{
+	int res;
+	char *s, *next, *buf = NULL;
+
+	res = ovl_path_getxattr(ofs, path, OVL_XATTR_REDIRECT, NULL, 0);
+	if (res == -ENODATA || res == -EOPNOTSUPP)
+		return NULL;
+	if (res < 0)
+		goto fail;
+	if (res == 0)
+		goto invalid;
+
+	buf = kzalloc(res + padding + 1, GFP_KERNEL);
+	if (!buf)
+		return ERR_PTR(-ENOMEM);
+
+	res = ovl_path_getxattr(ofs, path, OVL_XATTR_REDIRECT, buf, res);
+	if (res < 0)
+		goto fail;
+	if (res == 0)
+		goto invalid;
+
+	if (buf[0] == '/') {
+		for (s = buf; *s++ == '/'; s = next) {
+			next = strchrnul(s, '/');
+			if (s == next)
+				goto invalid;
+		}
+	} else {
+		if (strchr(buf, '/') != NULL)
+			goto invalid;
+	}
+
+	return buf;
+invalid:
+	pr_warn_ratelimited("invalid redirect (%s)\n", buf);
+	res = -EINVAL;
+	goto err_free;
+fail:
+	pr_warn_ratelimited("failed to get redirect (%i)\n", res);
+err_free:
+	kfree(buf);
+	return ERR_PTR(res);
+}
+
+/*
+ * ovl_sync_status() - Check fs sync status for volatile mounts
+ *
+ * Returns 1 if this is not a volatile mount and a real sync is required.
+ *
+ * Returns 0 if syncing can be skipped because mount is volatile, and no errors
+ * have occurred on the upperdir since the mount.
+ *
+ * Returns -errno if it is a volatile mount, and the error that occurred since
+ * the last mount. If the error code changes, it'll return the latest error
+ * code.
+ */
+
+int ovl_sync_status(struct ovl_fs *ofs)
+{
+	struct vfsmount *mnt;
+
+	if (ovl_should_sync(ofs))
+		return 1;
+
+	mnt = ovl_upper_mnt(ofs);
+	if (!mnt)
+		return 0;
+
+	return errseq_check(&mnt->mnt_sb->s_wb_err, ofs->errseq);
+}
+
+/*
+ * ovl_copyattr() - copy inode attributes from layer to ovl inode
+ *
+ * When overlay copies inode information from an upper or lower layer to the
+ * relevant overlay inode it will apply the idmapping of the upper or lower
+ * layer when doing so ensuring that the ovl inode ownership will correctly
+ * reflect the ownership of the idmapped upper or lower layer. For example, an
+ * idmapped upper or lower layer mapping id 1001 to id 1000 will take care to
+ * map any lower or upper inode owned by id 1001 to id 1000. These mapping
+ * helpers are nops when the relevant layer isn't idmapped.
+ */
+void ovl_copyattr(struct inode *inode)
+{
+	struct path realpath;
+	struct inode *realinode;
+	struct mnt_idmap *real_idmap;
+	vfsuid_t vfsuid;
+	vfsgid_t vfsgid;
+
+	ovl_i_path_real(inode, &realpath);
+	realinode = d_inode(realpath.dentry);
+	real_idmap = mnt_idmap(realpath.mnt);
+
+	vfsuid = i_uid_into_vfsuid(real_idmap, realinode);
+	vfsgid = i_gid_into_vfsgid(real_idmap, realinode);
+
+	inode->i_uid = vfsuid_into_kuid(vfsuid);
+	inode->i_gid = vfsgid_into_kgid(vfsgid);
+	inode->i_mode = realinode->i_mode;
+	inode->i_atime = realinode->i_atime;
+	inode->i_mtime = realinode->i_mtime;
+	inode->i_ctime = realinode->i_ctime;
+	i_size_write(inode, i_size_read(realinode));
+}