From 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 21 Feb 2023 18:24:12 -0800 Subject: Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 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(). ... --- fs/cifs/dfs.c | 543 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 543 insertions(+) create mode 100644 fs/cifs/dfs.c (limited to 'fs/cifs/dfs.c') diff --git a/fs/cifs/dfs.c b/fs/cifs/dfs.c new file mode 100644 index 000000000..b64d20374 --- /dev/null +++ b/fs/cifs/dfs.c @@ -0,0 +1,543 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2022 Paulo Alcantara + */ + +#include +#include "cifsproto.h" +#include "cifs_debug.h" +#include "dns_resolve.h" +#include "fs_context.h" +#include "dfs.h" + +/** + * dfs_parse_target_referral - set fs context for dfs target referral + * + * @full_path: full path in UNC format. + * @ref: dfs referral pointer. + * @ctx: smb3 fs context pointer. + * + * Return zero if dfs referral was parsed correctly, otherwise non-zero. + */ +int dfs_parse_target_referral(const char *full_path, const struct dfs_info3_param *ref, + struct smb3_fs_context *ctx) +{ + int rc; + const char *prepath = NULL; + char *path; + + if (!full_path || !*full_path || !ref || !ctx) + return -EINVAL; + + if (WARN_ON_ONCE(!ref->node_name || ref->path_consumed < 0)) + return -EINVAL; + + if (strlen(full_path) - ref->path_consumed) { + prepath = full_path + ref->path_consumed; + /* skip initial delimiter */ + if (*prepath == '/' || *prepath == '\\') + prepath++; + } + + path = cifs_build_devname(ref->node_name, prepath); + if (IS_ERR(path)) + return PTR_ERR(path); + + rc = smb3_parse_devname(path, ctx); + if (rc) + goto out; + + rc = dns_resolve_server_name_to_ip(path, (struct sockaddr *)&ctx->dstaddr, NULL); + +out: + kfree(path); + return rc; +} + +/* + * cifs_build_path_to_root returns full path to root when we do not have an + * existing connection (tcon) + */ +static char *build_unc_path_to_root(const struct smb3_fs_context *ctx, + const struct cifs_sb_info *cifs_sb, bool useppath) +{ + char *full_path, *pos; + unsigned int pplen = useppath && ctx->prepath ? strlen(ctx->prepath) + 1 : 0; + unsigned int unc_len = strnlen(ctx->UNC, MAX_TREE_SIZE + 1); + + if (unc_len > MAX_TREE_SIZE) + return ERR_PTR(-EINVAL); + + full_path = kmalloc(unc_len + pplen + 1, GFP_KERNEL); + if (full_path == NULL) + return ERR_PTR(-ENOMEM); + + memcpy(full_path, ctx->UNC, unc_len); + pos = full_path + unc_len; + + if (pplen) { + *pos = CIFS_DIR_SEP(cifs_sb); + memcpy(pos + 1, ctx->prepath, pplen); + pos += pplen; + } + + *pos = '\0'; /* add trailing null */ + convert_delimiter(full_path, CIFS_DIR_SEP(cifs_sb)); + cifs_dbg(FYI, "%s: full_path=%s\n", __func__, full_path); + return full_path; +} + +static int get_session(struct cifs_mount_ctx *mnt_ctx, const char *full_path) +{ + struct smb3_fs_context *ctx = mnt_ctx->fs_ctx; + int rc; + + ctx->leaf_fullpath = (char *)full_path; + rc = cifs_mount_get_session(mnt_ctx); + ctx->leaf_fullpath = NULL; + if (!rc) { + struct cifs_ses *ses = mnt_ctx->ses; + + mutex_lock(&ses->session_mutex); + ses->dfs_root_ses = mnt_ctx->root_ses; + mutex_unlock(&ses->session_mutex); + } + return rc; +} + +static void set_root_ses(struct cifs_mount_ctx *mnt_ctx) +{ + if (mnt_ctx->ses) { + spin_lock(&cifs_tcp_ses_lock); + mnt_ctx->ses->ses_count++; + spin_unlock(&cifs_tcp_ses_lock); + dfs_cache_add_refsrv_session(&mnt_ctx->mount_id, mnt_ctx->ses); + } + mnt_ctx->root_ses = mnt_ctx->ses; +} + +static int get_dfs_conn(struct cifs_mount_ctx *mnt_ctx, const char *ref_path, const char *full_path, + const struct dfs_cache_tgt_iterator *tit) +{ + struct smb3_fs_context *ctx = mnt_ctx->fs_ctx; + struct dfs_info3_param ref = {}; + int rc; + + rc = dfs_cache_get_tgt_referral(ref_path + 1, tit, &ref); + if (rc) + return rc; + + rc = dfs_parse_target_referral(full_path + 1, &ref, ctx); + if (rc) + goto out; + + cifs_mount_put_conns(mnt_ctx); + rc = get_session(mnt_ctx, ref_path); + if (rc) + goto out; + + if (ref.flags & DFSREF_REFERRAL_SERVER) + set_root_ses(mnt_ctx); + + rc = -EREMOTE; + if (ref.flags & DFSREF_STORAGE_SERVER) { + rc = cifs_mount_get_tcon(mnt_ctx); + if (rc) + goto out; + + /* some servers may not advertise referral capability under ref.flags */ + if (!(ref.flags & DFSREF_REFERRAL_SERVER) && + is_tcon_dfs(mnt_ctx->tcon)) + set_root_ses(mnt_ctx); + + rc = cifs_is_path_remote(mnt_ctx); + } + +out: + free_dfs_info_param(&ref); + return rc; +} + +static int __dfs_mount_share(struct cifs_mount_ctx *mnt_ctx) +{ + struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb; + struct smb3_fs_context *ctx = mnt_ctx->fs_ctx; + char *ref_path = NULL, *full_path = NULL; + struct dfs_cache_tgt_iterator *tit; + struct TCP_Server_Info *server; + char *origin_fullpath = NULL; + int num_links = 0; + int rc; + + ref_path = dfs_get_path(cifs_sb, ctx->UNC); + if (IS_ERR(ref_path)) + return PTR_ERR(ref_path); + + full_path = build_unc_path_to_root(ctx, cifs_sb, true); + if (IS_ERR(full_path)) { + rc = PTR_ERR(full_path); + full_path = NULL; + goto out; + } + + origin_fullpath = kstrdup(full_path, GFP_KERNEL); + if (!origin_fullpath) { + rc = -ENOMEM; + goto out; + } + + do { + struct dfs_cache_tgt_list tl = DFS_CACHE_TGT_LIST_INIT(tl); + + rc = dfs_get_referral(mnt_ctx, ref_path + 1, NULL, &tl); + if (rc) + break; + + tit = dfs_cache_get_tgt_iterator(&tl); + if (!tit) { + cifs_dbg(VFS, "%s: dfs referral (%s) with no targets\n", __func__, + ref_path + 1); + rc = -ENOENT; + dfs_cache_free_tgts(&tl); + break; + } + + do { + rc = get_dfs_conn(mnt_ctx, ref_path, full_path, tit); + if (!rc) + break; + if (rc == -EREMOTE) { + if (++num_links > MAX_NESTED_LINKS) { + rc = -ELOOP; + break; + } + kfree(ref_path); + kfree(full_path); + ref_path = full_path = NULL; + + full_path = build_unc_path_to_root(ctx, cifs_sb, true); + if (IS_ERR(full_path)) { + rc = PTR_ERR(full_path); + full_path = NULL; + } else { + ref_path = dfs_get_path(cifs_sb, full_path); + if (IS_ERR(ref_path)) { + rc = PTR_ERR(ref_path); + ref_path = NULL; + } + } + break; + } + } while ((tit = dfs_cache_get_next_tgt(&tl, tit))); + dfs_cache_free_tgts(&tl); + } while (rc == -EREMOTE); + + if (!rc) { + server = mnt_ctx->server; + + mutex_lock(&server->refpath_lock); + server->origin_fullpath = origin_fullpath; + server->current_fullpath = server->leaf_fullpath; + mutex_unlock(&server->refpath_lock); + origin_fullpath = NULL; + } + +out: + kfree(origin_fullpath); + kfree(ref_path); + kfree(full_path); + return rc; +} + +int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx, bool *isdfs) +{ + struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb; + struct smb3_fs_context *ctx = mnt_ctx->fs_ctx; + int rc; + + *isdfs = false; + + rc = get_session(mnt_ctx, NULL); + if (rc) + return rc; + mnt_ctx->root_ses = mnt_ctx->ses; + /* + * If called with 'nodfs' mount option, then skip DFS resolving. Otherwise unconditionally + * try to get an DFS referral (even cached) to determine whether it is an DFS mount. + * + * Skip prefix path to provide support for DFS referrals from w2k8 servers which don't seem + * to respond with PATH_NOT_COVERED to requests that include the prefix. + */ + if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS) || + dfs_get_referral(mnt_ctx, ctx->UNC + 1, NULL, NULL)) { + rc = cifs_mount_get_tcon(mnt_ctx); + if (rc) + return rc; + + rc = cifs_is_path_remote(mnt_ctx); + if (!rc || rc != -EREMOTE) + return rc; + } + + *isdfs = true; + set_root_ses(mnt_ctx); + + return __dfs_mount_share(mnt_ctx); +} + +/* Update dfs referral path of superblock */ +static int update_server_fullpath(struct TCP_Server_Info *server, struct cifs_sb_info *cifs_sb, + const char *target) +{ + int rc = 0; + size_t len = strlen(target); + char *refpath, *npath; + + if (unlikely(len < 2 || *target != '\\')) + return -EINVAL; + + if (target[1] == '\\') { + len += 1; + refpath = kmalloc(len, GFP_KERNEL); + if (!refpath) + return -ENOMEM; + + scnprintf(refpath, len, "%s", target); + } else { + len += sizeof("\\"); + refpath = kmalloc(len, GFP_KERNEL); + if (!refpath) + return -ENOMEM; + + scnprintf(refpath, len, "\\%s", target); + } + + npath = dfs_cache_canonical_path(refpath, cifs_sb->local_nls, cifs_remap(cifs_sb)); + kfree(refpath); + + if (IS_ERR(npath)) { + rc = PTR_ERR(npath); + } else { + mutex_lock(&server->refpath_lock); + kfree(server->leaf_fullpath); + server->leaf_fullpath = npath; + mutex_unlock(&server->refpath_lock); + server->current_fullpath = server->leaf_fullpath; + } + return rc; +} + +static int target_share_matches_server(struct TCP_Server_Info *server, char *share, + bool *target_match) +{ + int rc = 0; + const char *dfs_host; + size_t dfs_host_len; + + *target_match = true; + extract_unc_hostname(share, &dfs_host, &dfs_host_len); + + /* Check if hostnames or addresses match */ + cifs_server_lock(server); + if (dfs_host_len != strlen(server->hostname) || + strncasecmp(dfs_host, server->hostname, dfs_host_len)) { + cifs_dbg(FYI, "%s: %.*s doesn't match %s\n", __func__, + (int)dfs_host_len, dfs_host, server->hostname); + rc = match_target_ip(server, dfs_host, dfs_host_len, target_match); + if (rc) + cifs_dbg(VFS, "%s: failed to match target ip: %d\n", __func__, rc); + } + cifs_server_unlock(server); + return rc; +} + +static int __tree_connect_dfs_target(const unsigned int xid, struct cifs_tcon *tcon, + struct cifs_sb_info *cifs_sb, char *tree, bool islink, + struct dfs_cache_tgt_list *tl) +{ + int rc; + struct TCP_Server_Info *server = tcon->ses->server; + const struct smb_version_operations *ops = server->ops; + struct cifs_ses *root_ses = CIFS_DFS_ROOT_SES(tcon->ses); + struct cifs_tcon *ipc = root_ses->tcon_ipc; + char *share = NULL, *prefix = NULL; + struct dfs_cache_tgt_iterator *tit; + bool target_match; + + tit = dfs_cache_get_tgt_iterator(tl); + if (!tit) { + rc = -ENOENT; + goto out; + } + + /* Try to tree connect to all dfs targets */ + for (; tit; tit = dfs_cache_get_next_tgt(tl, tit)) { + const char *target = dfs_cache_get_tgt_name(tit); + struct dfs_cache_tgt_list ntl = DFS_CACHE_TGT_LIST_INIT(ntl); + + kfree(share); + kfree(prefix); + share = prefix = NULL; + + /* Check if share matches with tcp ses */ + rc = dfs_cache_get_tgt_share(server->current_fullpath + 1, tit, &share, &prefix); + if (rc) { + cifs_dbg(VFS, "%s: failed to parse target share: %d\n", __func__, rc); + break; + } + + rc = target_share_matches_server(server, share, &target_match); + if (rc) + break; + if (!target_match) { + rc = -EHOSTUNREACH; + continue; + } + + dfs_cache_noreq_update_tgthint(server->current_fullpath + 1, tit); + + if (ipc->need_reconnect) { + scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", server->hostname); + rc = ops->tree_connect(xid, ipc->ses, tree, ipc, cifs_sb->local_nls); + cifs_dbg(FYI, "%s: reconnect ipc: %d\n", __func__, rc); + } + + scnprintf(tree, MAX_TREE_SIZE, "\\%s", share); + if (!islink) { + rc = ops->tree_connect(xid, tcon->ses, tree, tcon, cifs_sb->local_nls); + break; + } + /* + * If no dfs referrals were returned from link target, then just do a TREE_CONNECT + * to it. Otherwise, cache the dfs referral and then mark current tcp ses for + * reconnect so either the demultiplex thread or the echo worker will reconnect to + * newly resolved target. + */ + if (dfs_cache_find(xid, root_ses, cifs_sb->local_nls, cifs_remap(cifs_sb), target, + NULL, &ntl)) { + rc = ops->tree_connect(xid, tcon->ses, tree, tcon, cifs_sb->local_nls); + if (rc) + continue; + + rc = cifs_update_super_prepath(cifs_sb, prefix); + } else { + /* Target is another dfs share */ + rc = update_server_fullpath(server, cifs_sb, target); + dfs_cache_free_tgts(tl); + + if (!rc) { + rc = -EREMOTE; + list_replace_init(&ntl.tl_list, &tl->tl_list); + } else + dfs_cache_free_tgts(&ntl); + } + break; + } + +out: + kfree(share); + kfree(prefix); + + return rc; +} + +static int tree_connect_dfs_target(const unsigned int xid, struct cifs_tcon *tcon, + struct cifs_sb_info *cifs_sb, char *tree, bool islink, + struct dfs_cache_tgt_list *tl) +{ + int rc; + int num_links = 0; + struct TCP_Server_Info *server = tcon->ses->server; + char *old_fullpath = server->leaf_fullpath; + + do { + rc = __tree_connect_dfs_target(xid, tcon, cifs_sb, tree, islink, tl); + if (!rc || rc != -EREMOTE) + break; + } while (rc = -ELOOP, ++num_links < MAX_NESTED_LINKS); + /* + * If we couldn't tree connect to any targets from last referral path, then + * retry it from newly resolved dfs referral. + */ + if (rc && server->leaf_fullpath != old_fullpath) + cifs_signal_cifsd_for_reconnect(server, true); + + dfs_cache_free_tgts(tl); + return rc; +} + +int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const struct nls_table *nlsc) +{ + int rc; + struct TCP_Server_Info *server = tcon->ses->server; + const struct smb_version_operations *ops = server->ops; + struct super_block *sb = NULL; + struct cifs_sb_info *cifs_sb; + struct dfs_cache_tgt_list tl = DFS_CACHE_TGT_LIST_INIT(tl); + char *tree; + struct dfs_info3_param ref = {0}; + + /* only send once per connect */ + spin_lock(&tcon->tc_lock); + if (tcon->ses->ses_status != SES_GOOD || + (tcon->status != TID_NEW && + tcon->status != TID_NEED_TCON)) { + spin_unlock(&tcon->tc_lock); + return 0; + } + tcon->status = TID_IN_TCON; + spin_unlock(&tcon->tc_lock); + + tree = kzalloc(MAX_TREE_SIZE, GFP_KERNEL); + if (!tree) { + rc = -ENOMEM; + goto out; + } + + if (tcon->ipc) { + cifs_server_lock(server); + scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", server->hostname); + cifs_server_unlock(server); + rc = ops->tree_connect(xid, tcon->ses, tree, tcon, nlsc); + goto out; + } + + sb = cifs_get_tcp_super(server); + if (IS_ERR(sb)) { + rc = PTR_ERR(sb); + cifs_dbg(VFS, "%s: could not find superblock: %d\n", __func__, rc); + goto out; + } + + cifs_sb = CIFS_SB(sb); + + /* If it is not dfs or there was no cached dfs referral, then reconnect to same share */ + if (!server->current_fullpath || + dfs_cache_noreq_find(server->current_fullpath + 1, &ref, &tl)) { + rc = ops->tree_connect(xid, tcon->ses, tcon->tree_name, tcon, cifs_sb->local_nls); + goto out; + } + + rc = tree_connect_dfs_target(xid, tcon, cifs_sb, tree, ref.server_type == DFS_TYPE_LINK, + &tl); + free_dfs_info_param(&ref); + +out: + kfree(tree); + cifs_put_tcp_super(sb); + + if (rc) { + spin_lock(&tcon->tc_lock); + if (tcon->status == TID_IN_TCON) + tcon->status = TID_NEED_TCON; + spin_unlock(&tcon->tc_lock); + } else { + spin_lock(&tcon->tc_lock); + if (tcon->status == TID_IN_TCON) + tcon->status = TID_GOOD; + spin_unlock(&tcon->tc_lock); + tcon->need_reconnect = false; + } + + return rc; +} -- cgit v1.2.3