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, 440 insertions, 0 deletions

diff --git a/fs/ntfs/index.c b/fs/ntfs/index.c
new file mode 100644
index 000000000..d46c2c03a
--- /dev/null
+++ b/fs/ntfs/index.c
@@ -0,0 +1,440 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * index.c - NTFS kernel index handling.  Part of the Linux-NTFS project.
+ *
+ * Copyright (c) 2004-2005 Anton Altaparmakov
+ */
+
+#include <linux/slab.h>
+
+#include "aops.h"
+#include "collate.h"
+#include "debug.h"
+#include "index.h"
+#include "ntfs.h"
+
+/**
+ * ntfs_index_ctx_get - allocate and initialize a new index context
+ * @idx_ni:	ntfs index inode with which to initialize the context
+ *
+ * Allocate a new index context, initialize it with @idx_ni and return it.
+ * Return NULL if allocation failed.
+ *
+ * Locking:  Caller must hold i_mutex on the index inode.
+ */
+ntfs_index_context *ntfs_index_ctx_get(ntfs_inode *idx_ni)
+{
+	ntfs_index_context *ictx;
+
+	ictx = kmem_cache_alloc(ntfs_index_ctx_cache, GFP_NOFS);
+	if (ictx)
+		*ictx = (ntfs_index_context){ .idx_ni = idx_ni };
+	return ictx;
+}
+
+/**
+ * ntfs_index_ctx_put - release an index context
+ * @ictx:	index context to free
+ *
+ * Release the index context @ictx, releasing all associated resources.
+ *
+ * Locking:  Caller must hold i_mutex on the index inode.
+ */
+void ntfs_index_ctx_put(ntfs_index_context *ictx)
+{
+	if (ictx->entry) {
+		if (ictx->is_in_root) {
+			if (ictx->actx)
+				ntfs_attr_put_search_ctx(ictx->actx);
+			if (ictx->base_ni)
+				unmap_mft_record(ictx->base_ni);
+		} else {
+			struct page *page = ictx->page;
+			if (page) {
+				BUG_ON(!PageLocked(page));
+				unlock_page(page);
+				ntfs_unmap_page(page);
+			}
+		}
+	}
+	kmem_cache_free(ntfs_index_ctx_cache, ictx);
+	return;
+}
+
+/**
+ * ntfs_index_lookup - find a key in an index and return its index entry
+ * @key:	[IN] key for which to search in the index
+ * @key_len:	[IN] length of @key in bytes
+ * @ictx:	[IN/OUT] context describing the index and the returned entry
+ *
+ * Before calling ntfs_index_lookup(), @ictx must have been obtained from a
+ * call to ntfs_index_ctx_get().
+ *
+ * Look for the @key in the index specified by the index lookup context @ictx.
+ * ntfs_index_lookup() walks the contents of the index looking for the @key.
+ *
+ * If the @key is found in the index, 0 is returned and @ictx is setup to
+ * describe the index entry containing the matching @key.  @ictx->entry is the
+ * index entry and @ictx->data and @ictx->data_len are the index entry data and
+ * its length in bytes, respectively.
+ *
+ * If the @key is not found in the index, -ENOENT is returned and @ictx is
+ * setup to describe the index entry whose key collates immediately after the
+ * search @key, i.e. this is the position in the index at which an index entry
+ * with a key of @key would need to be inserted.
+ *
+ * If an error occurs return the negative error code and @ictx is left
+ * untouched.
+ *
+ * When finished with the entry and its data, call ntfs_index_ctx_put() to free
+ * the context and other associated resources.
+ *
+ * If the index entry was modified, call flush_dcache_index_entry_page()
+ * immediately after the modification and either ntfs_index_entry_mark_dirty()
+ * or ntfs_index_entry_write() before the call to ntfs_index_ctx_put() to
+ * ensure that the changes are written to disk.
+ *
+ * Locking:  - Caller must hold i_mutex on the index inode.
+ *	     - Each page cache page in the index allocation mapping must be
+ *	       locked whilst being accessed otherwise we may find a corrupt
+ *	       page due to it being under ->writepage at the moment which
+ *	       applies the mst protection fixups before writing out and then
+ *	       removes them again after the write is complete after which it 
+ *	       unlocks the page.
+ */
+int ntfs_index_lookup(const void *key, const int key_len,
+		ntfs_index_context *ictx)
+{
+	VCN vcn, old_vcn;
+	ntfs_inode *idx_ni = ictx->idx_ni;
+	ntfs_volume *vol = idx_ni->vol;
+	struct super_block *sb = vol->sb;
+	ntfs_inode *base_ni = idx_ni->ext.base_ntfs_ino;
+	MFT_RECORD *m;
+	INDEX_ROOT *ir;
+	INDEX_ENTRY *ie;
+	INDEX_ALLOCATION *ia;
+	u8 *index_end, *kaddr;
+	ntfs_attr_search_ctx *actx;
+	struct address_space *ia_mapping;
+	struct page *page;
+	int rc, err = 0;
+
+	ntfs_debug("Entering.");
+	BUG_ON(!NInoAttr(idx_ni));
+	BUG_ON(idx_ni->type != AT_INDEX_ALLOCATION);
+	BUG_ON(idx_ni->nr_extents != -1);
+	BUG_ON(!base_ni);
+	BUG_ON(!key);
+	BUG_ON(key_len <= 0);
+	if (!ntfs_is_collation_rule_supported(
+			idx_ni->itype.index.collation_rule)) {
+		ntfs_error(sb, "Index uses unsupported collation rule 0x%x.  "
+				"Aborting lookup.", le32_to_cpu(
+				idx_ni->itype.index.collation_rule));
+		return -EOPNOTSUPP;
+	}
+	/* Get hold of the mft record for the index inode. */
+	m = map_mft_record(base_ni);
+	if (IS_ERR(m)) {
+		ntfs_error(sb, "map_mft_record() failed with error code %ld.",
+				-PTR_ERR(m));
+		return PTR_ERR(m);
+	}
+	actx = ntfs_attr_get_search_ctx(base_ni, m);
+	if (unlikely(!actx)) {
+		err = -ENOMEM;
+		goto err_out;
+	}
+	/* Find the index root attribute in the mft record. */
+	err = ntfs_attr_lookup(AT_INDEX_ROOT, idx_ni->name, idx_ni->name_len,
+			CASE_SENSITIVE, 0, NULL, 0, actx);
+	if (unlikely(err)) {
+		if (err == -ENOENT) {
+			ntfs_error(sb, "Index root attribute missing in inode "
+					"0x%lx.", idx_ni->mft_no);
+			err = -EIO;
+		}
+		goto err_out;
+	}
+	/* Get to the index root value (it has been verified in read_inode). */
+	ir = (INDEX_ROOT*)((u8*)actx->attr +
+			le16_to_cpu(actx->attr->data.resident.value_offset));
+	index_end = (u8*)&ir->index + le32_to_cpu(ir->index.index_length);
+	/* The first index entry. */
+	ie = (INDEX_ENTRY*)((u8*)&ir->index +
+			le32_to_cpu(ir->index.entries_offset));
+	/*
+	 * Loop until we exceed valid memory (corruption case) or until we
+	 * reach the last entry.
+	 */
+	for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
+		/* Bounds checks. */
+		if ((u8*)ie < (u8*)actx->mrec || (u8*)ie +
+				sizeof(INDEX_ENTRY_HEADER) > index_end ||
+				(u8*)ie + le16_to_cpu(ie->length) > index_end)
+			goto idx_err_out;
+		/*
+		 * The last entry cannot contain a key.  It can however contain
+		 * a pointer to a child node in the B+tree so we just break out.
+		 */
+		if (ie->flags & INDEX_ENTRY_END)
+			break;
+		/* Further bounds checks. */
+		if ((u32)sizeof(INDEX_ENTRY_HEADER) +
+				le16_to_cpu(ie->key_length) >
+				le16_to_cpu(ie->data.vi.data_offset) ||
+				(u32)le16_to_cpu(ie->data.vi.data_offset) +
+				le16_to_cpu(ie->data.vi.data_length) >
+				le16_to_cpu(ie->length))
+			goto idx_err_out;
+		/* If the keys match perfectly, we setup @ictx and return 0. */
+		if ((key_len == le16_to_cpu(ie->key_length)) && !memcmp(key,
+				&ie->key, key_len)) {
+ir_done:
+			ictx->is_in_root = true;
+			ictx->ir = ir;
+			ictx->actx = actx;
+			ictx->base_ni = base_ni;
+			ictx->ia = NULL;
+			ictx->page = NULL;
+done:
+			ictx->entry = ie;
+			ictx->data = (u8*)ie +
+					le16_to_cpu(ie->data.vi.data_offset);
+			ictx->data_len = le16_to_cpu(ie->data.vi.data_length);
+			ntfs_debug("Done.");
+			return err;
+		}
+		/*
+		 * Not a perfect match, need to do full blown collation so we
+		 * know which way in the B+tree we have to go.
+		 */
+		rc = ntfs_collate(vol, idx_ni->itype.index.collation_rule, key,
+				key_len, &ie->key, le16_to_cpu(ie->key_length));
+		/*
+		 * If @key collates before the key of the current entry, there
+		 * is definitely no such key in this index but we might need to
+		 * descend into the B+tree so we just break out of the loop.
+		 */
+		if (rc == -1)
+			break;
+		/*
+		 * A match should never happen as the memcmp() call should have
+		 * cought it, but we still treat it correctly.
+		 */
+		if (!rc)
+			goto ir_done;
+		/* The keys are not equal, continue the search. */
+	}
+	/*
+	 * We have finished with this index without success.  Check for the
+	 * presence of a child node and if not present setup @ictx and return
+	 * -ENOENT.
+	 */
+	if (!(ie->flags & INDEX_ENTRY_NODE)) {
+		ntfs_debug("Entry not found.");
+		err = -ENOENT;
+		goto ir_done;
+	} /* Child node present, descend into it. */
+	/* Consistency check: Verify that an index allocation exists. */
+	if (!NInoIndexAllocPresent(idx_ni)) {
+		ntfs_error(sb, "No index allocation attribute but index entry "
+				"requires one.  Inode 0x%lx is corrupt or "
+				"driver bug.", idx_ni->mft_no);
+		goto err_out;
+	}
+	/* Get the starting vcn of the index_block holding the child node. */
+	vcn = sle64_to_cpup((sle64*)((u8*)ie + le16_to_cpu(ie->length) - 8));
+	ia_mapping = VFS_I(idx_ni)->i_mapping;
+	/*
+	 * We are done with the index root and the mft record.  Release them,
+	 * otherwise we deadlock with ntfs_map_page().
+	 */
+	ntfs_attr_put_search_ctx(actx);
+	unmap_mft_record(base_ni);
+	m = NULL;
+	actx = NULL;
+descend_into_child_node:
+	/*
+	 * Convert vcn to index into the index allocation attribute in units
+	 * of PAGE_SIZE and map the page cache page, reading it from
+	 * disk if necessary.
+	 */
+	page = ntfs_map_page(ia_mapping, vcn <<
+			idx_ni->itype.index.vcn_size_bits >> PAGE_SHIFT);
+	if (IS_ERR(page)) {
+		ntfs_error(sb, "Failed to map index page, error %ld.",
+				-PTR_ERR(page));
+		err = PTR_ERR(page);
+		goto err_out;
+	}
+	lock_page(page);
+	kaddr = (u8*)page_address(page);
+fast_descend_into_child_node:
+	/* Get to the index allocation block. */
+	ia = (INDEX_ALLOCATION*)(kaddr + ((vcn <<
+			idx_ni->itype.index.vcn_size_bits) & ~PAGE_MASK));
+	/* Bounds checks. */
+	if ((u8*)ia < kaddr || (u8*)ia > kaddr + PAGE_SIZE) {
+		ntfs_error(sb, "Out of bounds check failed.  Corrupt inode "
+				"0x%lx or driver bug.", idx_ni->mft_no);
+		goto unm_err_out;
+	}
+	/* Catch multi sector transfer fixup errors. */
+	if (unlikely(!ntfs_is_indx_record(ia->magic))) {
+		ntfs_error(sb, "Index record with vcn 0x%llx is corrupt.  "
+				"Corrupt inode 0x%lx.  Run chkdsk.",
+				(long long)vcn, idx_ni->mft_no);
+		goto unm_err_out;
+	}
+	if (sle64_to_cpu(ia->index_block_vcn) != vcn) {
+		ntfs_error(sb, "Actual VCN (0x%llx) of index buffer is "
+				"different from expected VCN (0x%llx).  Inode "
+				"0x%lx is corrupt or driver bug.",
+				(unsigned long long)
+				sle64_to_cpu(ia->index_block_vcn),
+				(unsigned long long)vcn, idx_ni->mft_no);
+		goto unm_err_out;
+	}
+	if (le32_to_cpu(ia->index.allocated_size) + 0x18 !=
+			idx_ni->itype.index.block_size) {
+		ntfs_error(sb, "Index buffer (VCN 0x%llx) of inode 0x%lx has "
+				"a size (%u) differing from the index "
+				"specified size (%u).  Inode is corrupt or "
+				"driver bug.", (unsigned long long)vcn,
+				idx_ni->mft_no,
+				le32_to_cpu(ia->index.allocated_size) + 0x18,
+				idx_ni->itype.index.block_size);
+		goto unm_err_out;
+	}
+	index_end = (u8*)ia + idx_ni->itype.index.block_size;
+	if (index_end > kaddr + PAGE_SIZE) {
+		ntfs_error(sb, "Index buffer (VCN 0x%llx) of inode 0x%lx "
+				"crosses page boundary.  Impossible!  Cannot "
+				"access!  This is probably a bug in the "
+				"driver.", (unsigned long long)vcn,
+				idx_ni->mft_no);
+		goto unm_err_out;
+	}
+	index_end = (u8*)&ia->index + le32_to_cpu(ia->index.index_length);
+	if (index_end > (u8*)ia + idx_ni->itype.index.block_size) {
+		ntfs_error(sb, "Size of index buffer (VCN 0x%llx) of inode "
+				"0x%lx exceeds maximum size.",
+				(unsigned long long)vcn, idx_ni->mft_no);
+		goto unm_err_out;
+	}
+	/* The first index entry. */
+	ie = (INDEX_ENTRY*)((u8*)&ia->index +
+			le32_to_cpu(ia->index.entries_offset));
+	/*
+	 * Iterate similar to above big loop but applied to index buffer, thus
+	 * loop until we exceed valid memory (corruption case) or until we
+	 * reach the last entry.
+	 */
+	for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
+		/* Bounds checks. */
+		if ((u8*)ie < (u8*)ia || (u8*)ie +
+				sizeof(INDEX_ENTRY_HEADER) > index_end ||
+				(u8*)ie + le16_to_cpu(ie->length) > index_end) {
+			ntfs_error(sb, "Index entry out of bounds in inode "
+					"0x%lx.", idx_ni->mft_no);
+			goto unm_err_out;
+		}
+		/*
+		 * The last entry cannot contain a key.  It can however contain
+		 * a pointer to a child node in the B+tree so we just break out.
+		 */
+		if (ie->flags & INDEX_ENTRY_END)
+			break;
+		/* Further bounds checks. */
+		if ((u32)sizeof(INDEX_ENTRY_HEADER) +
+				le16_to_cpu(ie->key_length) >
+				le16_to_cpu(ie->data.vi.data_offset) ||
+				(u32)le16_to_cpu(ie->data.vi.data_offset) +
+				le16_to_cpu(ie->data.vi.data_length) >
+				le16_to_cpu(ie->length)) {
+			ntfs_error(sb, "Index entry out of bounds in inode "
+					"0x%lx.", idx_ni->mft_no);
+			goto unm_err_out;
+		}
+		/* If the keys match perfectly, we setup @ictx and return 0. */
+		if ((key_len == le16_to_cpu(ie->key_length)) && !memcmp(key,
+				&ie->key, key_len)) {
+ia_done:
+			ictx->is_in_root = false;
+			ictx->actx = NULL;
+			ictx->base_ni = NULL;
+			ictx->ia = ia;
+			ictx->page = page;
+			goto done;
+		}
+		/*
+		 * Not a perfect match, need to do full blown collation so we
+		 * know which way in the B+tree we have to go.
+		 */
+		rc = ntfs_collate(vol, idx_ni->itype.index.collation_rule, key,
+				key_len, &ie->key, le16_to_cpu(ie->key_length));
+		/*
+		 * If @key collates before the key of the current entry, there
+		 * is definitely no such key in this index but we might need to
+		 * descend into the B+tree so we just break out of the loop.
+		 */
+		if (rc == -1)
+			break;
+		/*
+		 * A match should never happen as the memcmp() call should have
+		 * cought it, but we still treat it correctly.
+		 */
+		if (!rc)
+			goto ia_done;
+		/* The keys are not equal, continue the search. */
+	}
+	/*
+	 * We have finished with this index buffer without success.  Check for
+	 * the presence of a child node and if not present return -ENOENT.
+	 */
+	if (!(ie->flags & INDEX_ENTRY_NODE)) {
+		ntfs_debug("Entry not found.");
+		err = -ENOENT;
+		goto ia_done;
+	}
+	if ((ia->index.flags & NODE_MASK) == LEAF_NODE) {
+		ntfs_error(sb, "Index entry with child node found in a leaf "
+				"node in inode 0x%lx.", idx_ni->mft_no);
+		goto unm_err_out;
+	}
+	/* Child node present, descend into it. */
+	old_vcn = vcn;
+	vcn = sle64_to_cpup((sle64*)((u8*)ie + le16_to_cpu(ie->length) - 8));
+	if (vcn >= 0) {
+		/*
+		 * If vcn is in the same page cache page as old_vcn we recycle
+		 * the mapped page.
+		 */
+		if (old_vcn << vol->cluster_size_bits >>
+				PAGE_SHIFT == vcn <<
+				vol->cluster_size_bits >>
+				PAGE_SHIFT)
+			goto fast_descend_into_child_node;
+		unlock_page(page);
+		ntfs_unmap_page(page);
+		goto descend_into_child_node;
+	}
+	ntfs_error(sb, "Negative child node vcn in inode 0x%lx.",
+			idx_ni->mft_no);
+unm_err_out:
+	unlock_page(page);
+	ntfs_unmap_page(page);
+err_out:
+	if (!err)
+		err = -EIO;
+	if (actx)
+		ntfs_attr_put_search_ctx(actx);
+	if (m)
+		unmap_mft_record(base_ni);
+	return err;
+idx_err_out:
+	ntfs_error(sb, "Corrupt index.  Aborting lookup.");
+	goto err_out;
+}