Revision f085df1be60abf670315c11036261cfaec16b2eb authored by Linus Torvalds on 07 May 2023, 18:32:18 UTC, committed by Linus Torvalds on 07 May 2023, 18:32:18 UTC
Pull perf tool updates from Arnaldo Carvalho de Melo: "Third version of perf tool updates, with the build problems with with using a 'vmlinux.h' generated from the main build fixed, and the bpf skeleton build disabled by default. Build: - Require libtraceevent to build, one can disable it using NO_LIBTRACEEVENT=1. It is required for tools like 'perf sched', 'perf kvm', 'perf trace', etc. libtraceevent is available in most distros so installing 'libtraceevent-devel' should be a one-time event to continue building perf as usual. Using NO_LIBTRACEEVENT=1 produces tooling that is functional and sufficient for lots of users not interested in those libtraceevent dependent features. - Allow Python support in 'perf script' when libtraceevent isn't linked, as not all features requires it, for instance Intel PT does not use tracepoints. - Error if the python interpreter needed for jevents to work isn't available and NO_JEVENTS=1 isn't set, preventing a build without support for JSON vendor events, which is a rare but possible condition. The two check error messages: $(error ERROR: No python interpreter needed for jevents generation. Install python or build with NO_JEVENTS=1.) $(error ERROR: Python interpreter needed for jevents generation too old (older than 3.6). Install a newer python or build with NO_JEVENTS=1.) - Make libbpf 1.0 the minimum required when building with out of tree, distro provided libbpf. - Use libsdtc++'s and LLVM's libcxx's __cxa_demangle, a portable C++ demangler, add 'perf test' entry for it. - Make binutils libraries opt in, as distros disable building with it due to licensing, they were used for C++ demangling, for instance. - Switch libpfm4 to opt-out rather than opt-in, if libpfm-devel (or equivalent) isn't installed, we'll just have a build warning: Makefile.config:1144: libpfm4 not found, disables libpfm4 support. Please install libpfm4-dev - Add a feature test for scandirat(), that is not implemented so far in musl and uclibc, disabling features that need it, such as scanning for tracepoints in /sys/kernel/tracing/events. perf BPF filters: - New feature where BPF can be used to filter samples, for instance: $ sudo ./perf record -e cycles --filter 'period > 1000' true $ sudo ./perf script perf-exec 2273949 546850.708501: 5029 cycles: ffffffff826f9e25 finish_wait+0x5 ([kernel.kallsyms]) perf-exec 2273949 546850.708508: 32409 cycles: ffffffff826f9e25 finish_wait+0x5 ([kernel.kallsyms]) perf-exec 2273949 546850.708526: 143369 cycles: ffffffff82b4cdbf xas_start+0x5f ([kernel.kallsyms]) perf-exec 2273949 546850.708600: 372650 cycles: ffffffff8286b8f7 __pagevec_lru_add+0x117 ([kernel.kallsyms]) perf-exec 2273949 546850.708791: 482953 cycles: ffffffff829190de __mod_memcg_lruvec_state+0x4e ([kernel.kallsyms]) true 2273949 546850.709036: 501985 cycles: ffffffff828add7c tlb_gather_mmu+0x4c ([kernel.kallsyms]) true 2273949 546850.709292: 503065 cycles: 7f2446d97c03 _dl_map_object_deps+0x973 (/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2) - In addition to 'period' (PERF_SAMPLE_PERIOD), the other PERF_SAMPLE_ can be used for filtering, and also some other sample accessible values, from tools/perf/Documentation/perf-record.txt: Essentially the BPF filter expression is: <term> <operator> <value> (("," | "||") <term> <operator> <value>)* The <term> can be one of: ip, id, tid, pid, cpu, time, addr, period, txn, weight, phys_addr, code_pgsz, data_pgsz, weight1, weight2, weight3, ins_lat, retire_lat, p_stage_cyc, mem_op, mem_lvl, mem_snoop, mem_remote, mem_lock, mem_dtlb, mem_blk, mem_hops The <operator> can be one of: ==, !=, >, >=, <, <=, & The <value> can be one of: <number> (for any term) na, load, store, pfetch, exec (for mem_op) l1, l2, l3, l4, cxl, io, any_cache, lfb, ram, pmem (for mem_lvl) na, none, hit, miss, hitm, fwd, peer (for mem_snoop) remote (for mem_remote) na, locked (for mem_locked) na, l1_hit, l1_miss, l2_hit, l2_miss, any_hit, any_miss, walk, fault (for mem_dtlb) na, by_data, by_addr (for mem_blk) hops0, hops1, hops2, hops3 (for mem_hops) perf lock contention: - Show lock type with address. - Track and show mmap_lock, siglock and per-cpu rq_lock with address. This is done for mmap_lock by following the current->mm pointer: $ sudo ./perf lock con -abl -- sleep 10 contended total wait max wait avg wait address symbol ... 16344 312.30 ms 2.22 ms 19.11 us ffff8cc702595640 17686 310.08 ms 1.49 ms 17.53 us ffff8cc7025952c0 3 84.14 ms 45.79 ms 28.05 ms ffff8cc78114c478 mmap_lock 3557 76.80 ms 68.75 us 21.59 us ffff8cc77ca3af58 1 68.27 ms 68.27 ms 68.27 ms ffff8cda745dfd70 9 54.53 ms 7.96 ms 6.06 ms ffff8cc7642a48b8 mmap_lock 14629 44.01 ms 60.00 us 3.01 us ffff8cc7625f9ca0 3481 42.63 ms 140.71 us 12.24 us ffffffff937906ac vmap_area_lock 16194 38.73 ms 42.15 us 2.39 us ffff8cd397cbc560 11 38.44 ms 10.39 ms 3.49 ms ffff8ccd6d12fbb8 mmap_lock 1 5.43 ms 5.43 ms 5.43 ms ffff8cd70018f0d8 1674 5.38 ms 422.93 us 3.21 us ffffffff92e06080 tasklist_lock 581 4.51 ms 130.68 us 7.75 us ffff8cc9b1259058 5 3.52 ms 1.27 ms 703.23 us ffff8cc754510070 112 3.47 ms 56.47 us 31.02 us ffff8ccee38b3120 381 3.31 ms 73.44 us 8.69 us ffffffff93790690 purge_vmap_area_lock 255 3.19 ms 36.35 us 12.49 us ffff8d053ce30c80 - Update default map size to 16384. - Allocate single letter option -M for --map-nr-entries, as it is proving being frequently used. - Fix struct rq lock access for older kernels with BPF's CO-RE (Compile once, run everywhere). - Fix problems found with MSAn. perf report/top: - Add inline information when using --call-graph=fp or lbr, as was already done to the --call-graph=dwarf callchain mode. - Improve the 'srcfile' sort key performance by really using an optimization introduced in 6.2 for the 'srcline' sort key that avoids calling addr2line for comparision with each sample. perf sched: - Make 'perf sched latency/map/replay' to use "sched:sched_waking" instead of "sched:sched_waking", consistent with 'perf record' since d566a9c2d482 ("perf sched: Prefer sched_waking event when it exists"). perf ftrace: - Make system wide the default target for latency subcommand, run the following command then generate some network traffic and press control+C: # perf ftrace latency -T __kfree_skb ^C DURATION | COUNT | GRAPH | 0 - 1 us | 27 | ############# | 1 - 2 us | 22 | ########### | 2 - 4 us | 8 | #### | 4 - 8 us | 5 | ## | 8 - 16 us | 24 | ############ | 16 - 32 us | 2 | # | 32 - 64 us | 1 | | 64 - 128 us | 0 | | 128 - 256 us | 0 | | 256 - 512 us | 0 | | 512 - 1024 us | 0 | | 1 - 2 ms | 0 | | 2 - 4 ms | 0 | | 4 - 8 ms | 0 | | 8 - 16 ms | 0 | | 16 - 32 ms | 0 | | 32 - 64 ms | 0 | | 64 - 128 ms | 0 | | 128 - 256 ms | 0 | | 256 - 512 ms | 0 | | 512 - 1024 ms | 0 | | 1 - ... s | 0 | | # perf top: - Add --branch-history (LBR: Last Branch Record) option, just like already available for 'perf record'. - Fix segfault in thread__comm_len() where thread->comm was being used outside thread->comm_lock. perf annotate: - Allow configuring objdump and addr2line in ~/.perfconfig., so that you can use alternative binaries, such as llvm's. perf kvm: - Add TUI mode for 'perf kvm stat report'. Reference counting: - Add reference count checking infrastructure to check for use after free, done to the 'cpumap', 'namespaces', 'maps' and 'map' structs, more to come. To build with it use -DREFCNT_CHECKING=1 in the make command line to build tools/perf. Documented at: https://perf.wiki.kernel.org/index.php/Reference_Count_Checking - The above caught, for instance, fix, present in this series: - Fix maps use after put in 'perf test "Share thread maps"': 'maps' is copied from leader, but the leader is put on line 79 and then 'maps' is used to read the reference count below - so a use after put, with the put of maps happening within thread__put. Fixed by reversing the order of puts so that the leader is put last. - Also several fixes were made to places where reference counts were not being held. - Make this one of the tests in 'make -C tools/perf build-test' to regularly build test it and to make sure no direct access to the reference counted structs are made, doing that via accessors to check the validity of the struct pointer. ARM64: - Fix 'perf report' segfault when filtering coresight traces by sparse lists of CPUs. - Add support for 'simd' as a sort field for 'perf report', to show ARM's NEON SIMD's predicate flags: "partial" and "empty". arm64 vendor events: - Add N1 metrics. Intel vendor events: - Add graniterapids, grandridge and sierraforrest events. - Refresh events for: alderlake, aldernaken, broadwell, broadwellde, broadwellx, cascadelakx, haswell, haswellx, icelake, icelakex, jaketown, meteorlake, knightslanding, sandybridge, sapphirerapids, silvermont, skylake, tigerlake and westmereep-dp - Refresh metrics for alderlake-n, broadwell, broadwellde, broadwellx, haswell, haswellx, icelakex, ivybridge, ivytown and skylakex. perf stat: - Implement --topdown using JSON metrics. - Add TopdownL1 JSON metric as a default if present, but disable it for now for some Intel hybrid architectures, a series of patches addressing this is being reviewed and will be submitted for v6.5. - Use metrics for --smi-cost. - Update topdown documentation. Vendor events (JSON) infrastructure: - Add support for computing and printing metric threshold values. For instance, here is one found in thesapphirerapids json file: { "BriefDescription": "Percentage of cycles spent in System Management Interrupts.", "MetricExpr": "((msr@aperf@ - cycles) / msr@aperf@ if msr@smi@ > 0 else 0)", "MetricGroup": "smi", "MetricName": "smi_cycles", "MetricThreshold": "smi_cycles > 0.1", "ScaleUnit": "100%" }, - Test parsing metric thresholds with the fake PMU in 'perf test pmu-events'. - Support for printing metric thresholds in 'perf list'. - Add --metric-no-threshold option to 'perf stat'. - Add rand (reverse and) and has_pmem (optane memory) support to metrics. - Sort list of input files to avoid depending on the order from readdir() helping in obtaining reproducible builds. S/390: - Add common metrics: - CPI (cycles per instruction), prbstate (ratio of instructions executed in problem state compared to total number of instructions), l1mp (Level one instruction and data cache misses per 100 instructions). - Add cache metrics for z13, z14, z15 and z16. - Add metric for TLB and cache. ARM: - Add raw decoding for SPE (Statistical Profiling Extension) v1.3 MTE (Memory Tagging Extension) and MOPS (Memory Operations) load/store. Intel PT hardware tracing: - Add event type names UINTR (User interrupt delivered) and UIRET (Exiting from user interrupt routine), documented in table 32-50 "CFE Packet Type and Vector Fields Details" in the Intel Processor Trace chapter of The Intel SDM Volume 3 version 078. - Add support for new branch instructions ERETS and ERETU. - Fix CYC timestamps after standalone CBR ARM CoreSight hardware tracing: - Allow user to override timestamp and contextid settings. - Fix segfault in dso lookup. - Fix timeless decode mode detection. - Add separate decode paths for timeless and per-thread modes. auxtrace: - Fix address filter entire kernel size. Miscellaneous: - Fix use-after-free and unaligned bugs in the PLT handling routines. - Use zfree() to reduce chances of use after free. - Add missing 0x prefix for addresses printed in hexadecimal in 'perf probe'. - Suppress massive unsupported target platform errors in the unwind code. - Fix return incorrect build_id size in elf_read_build_id(). - Fix 'perf scripts intel-pt-events.py' IPC output for Python 2 . - Add missing new parameter in kfree_skb tracepoint to the python scripts using it. - Add 'perf bench syscall fork' benchmark. - Add support for printing PERF_MEM_LVLNUM_UNC (Uncached access) in 'perf mem'. - Fix wrong size expectation for perf test 'Setup struct perf_event_attr' caused by the patch adding perf_event_attr::config3. - Fix some spelling mistakes" * tag 'perf-tools-for-v6.4-3-2023-05-06' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux: (365 commits) Revert "perf build: Make BUILD_BPF_SKEL default, rename to NO_BPF_SKEL" Revert "perf build: Warn for BPF skeletons if endian mismatches" perf metrics: Fix SEGV with --for-each-cgroup perf bpf skels: Stop using vmlinux.h generated from BTF, use subset of used structs + CO-RE perf stat: Separate bperf from bpf_profiler perf test record+probe_libc_inet_pton: Fix call chain match on x86_64 perf test record+probe_libc_inet_pton: Fix call chain match on s390 perf tracepoint: Fix memory leak in is_valid_tracepoint() perf cs-etm: Add fix for coresight trace for any range of CPUs perf build: Fix unescaped # in perf build-test perf unwind: Suppress massive unsupported target platform errors perf script: Add new parameter in kfree_skb tracepoint to the python scripts using it perf script: Print raw ip instead of binary offset for callchain perf symbols: Fix return incorrect build_id size in elf_read_build_id() perf list: Modify the warning message about scandirat(3) perf list: Fix memory leaks in print_tracepoint_events() perf lock contention: Rework offset calculation with BPF CO-RE perf lock contention: Fix struct rq lock access perf stat: Disable TopdownL1 on hybrid perf stat: Avoid SEGV on counter->name ...
cell.c
// SPDX-License-Identifier: GPL-2.0-or-later
/* AFS cell and server record management
*
* Copyright (C) 2002, 2017 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/slab.h>
#include <linux/key.h>
#include <linux/ctype.h>
#include <linux/dns_resolver.h>
#include <linux/sched.h>
#include <linux/inet.h>
#include <linux/namei.h>
#include <keys/rxrpc-type.h>
#include "internal.h"
static unsigned __read_mostly afs_cell_gc_delay = 10;
static unsigned __read_mostly afs_cell_min_ttl = 10 * 60;
static unsigned __read_mostly afs_cell_max_ttl = 24 * 60 * 60;
static atomic_t cell_debug_id;
static void afs_queue_cell_manager(struct afs_net *);
static void afs_manage_cell_work(struct work_struct *);
static void afs_dec_cells_outstanding(struct afs_net *net)
{
if (atomic_dec_and_test(&net->cells_outstanding))
wake_up_var(&net->cells_outstanding);
}
/*
* Set the cell timer to fire after a given delay, assuming it's not already
* set for an earlier time.
*/
static void afs_set_cell_timer(struct afs_net *net, time64_t delay)
{
if (net->live) {
atomic_inc(&net->cells_outstanding);
if (timer_reduce(&net->cells_timer, jiffies + delay * HZ))
afs_dec_cells_outstanding(net);
} else {
afs_queue_cell_manager(net);
}
}
/*
* Look up and get an activation reference on a cell record. The caller must
* hold net->cells_lock at least read-locked.
*/
static struct afs_cell *afs_find_cell_locked(struct afs_net *net,
const char *name, unsigned int namesz,
enum afs_cell_trace reason)
{
struct afs_cell *cell = NULL;
struct rb_node *p;
int n;
_enter("%*.*s", namesz, namesz, name);
if (name && namesz == 0)
return ERR_PTR(-EINVAL);
if (namesz > AFS_MAXCELLNAME)
return ERR_PTR(-ENAMETOOLONG);
if (!name) {
cell = net->ws_cell;
if (!cell)
return ERR_PTR(-EDESTADDRREQ);
goto found;
}
p = net->cells.rb_node;
while (p) {
cell = rb_entry(p, struct afs_cell, net_node);
n = strncasecmp(cell->name, name,
min_t(size_t, cell->name_len, namesz));
if (n == 0)
n = cell->name_len - namesz;
if (n < 0)
p = p->rb_left;
else if (n > 0)
p = p->rb_right;
else
goto found;
}
return ERR_PTR(-ENOENT);
found:
return afs_use_cell(cell, reason);
}
/*
* Look up and get an activation reference on a cell record.
*/
struct afs_cell *afs_find_cell(struct afs_net *net,
const char *name, unsigned int namesz,
enum afs_cell_trace reason)
{
struct afs_cell *cell;
down_read(&net->cells_lock);
cell = afs_find_cell_locked(net, name, namesz, reason);
up_read(&net->cells_lock);
return cell;
}
/*
* Set up a cell record and fill in its name, VL server address list and
* allocate an anonymous key
*/
static struct afs_cell *afs_alloc_cell(struct afs_net *net,
const char *name, unsigned int namelen,
const char *addresses)
{
struct afs_vlserver_list *vllist;
struct afs_cell *cell;
int i, ret;
ASSERT(name);
if (namelen == 0)
return ERR_PTR(-EINVAL);
if (namelen > AFS_MAXCELLNAME) {
_leave(" = -ENAMETOOLONG");
return ERR_PTR(-ENAMETOOLONG);
}
/* Prohibit cell names that contain unprintable chars, '/' and '@' or
* that begin with a dot. This also precludes "@cell".
*/
if (name[0] == '.')
return ERR_PTR(-EINVAL);
for (i = 0; i < namelen; i++) {
char ch = name[i];
if (!isprint(ch) || ch == '/' || ch == '@')
return ERR_PTR(-EINVAL);
}
_enter("%*.*s,%s", namelen, namelen, name, addresses);
cell = kzalloc(sizeof(struct afs_cell), GFP_KERNEL);
if (!cell) {
_leave(" = -ENOMEM");
return ERR_PTR(-ENOMEM);
}
cell->name = kmalloc(namelen + 1, GFP_KERNEL);
if (!cell->name) {
kfree(cell);
return ERR_PTR(-ENOMEM);
}
cell->net = net;
cell->name_len = namelen;
for (i = 0; i < namelen; i++)
cell->name[i] = tolower(name[i]);
cell->name[i] = 0;
refcount_set(&cell->ref, 1);
atomic_set(&cell->active, 0);
INIT_WORK(&cell->manager, afs_manage_cell_work);
cell->volumes = RB_ROOT;
INIT_HLIST_HEAD(&cell->proc_volumes);
seqlock_init(&cell->volume_lock);
cell->fs_servers = RB_ROOT;
seqlock_init(&cell->fs_lock);
INIT_LIST_HEAD(&cell->fs_open_mmaps);
init_rwsem(&cell->fs_open_mmaps_lock);
rwlock_init(&cell->vl_servers_lock);
cell->flags = (1 << AFS_CELL_FL_CHECK_ALIAS);
/* Provide a VL server list, filling it in if we were given a list of
* addresses to use.
*/
if (addresses) {
vllist = afs_parse_text_addrs(net,
addresses, strlen(addresses), ':',
VL_SERVICE, AFS_VL_PORT);
if (IS_ERR(vllist)) {
ret = PTR_ERR(vllist);
goto parse_failed;
}
vllist->source = DNS_RECORD_FROM_CONFIG;
vllist->status = DNS_LOOKUP_NOT_DONE;
cell->dns_expiry = TIME64_MAX;
} else {
ret = -ENOMEM;
vllist = afs_alloc_vlserver_list(0);
if (!vllist)
goto error;
vllist->source = DNS_RECORD_UNAVAILABLE;
vllist->status = DNS_LOOKUP_NOT_DONE;
cell->dns_expiry = ktime_get_real_seconds();
}
rcu_assign_pointer(cell->vl_servers, vllist);
cell->dns_source = vllist->source;
cell->dns_status = vllist->status;
smp_store_release(&cell->dns_lookup_count, 1); /* vs source/status */
atomic_inc(&net->cells_outstanding);
cell->debug_id = atomic_inc_return(&cell_debug_id);
trace_afs_cell(cell->debug_id, 1, 0, afs_cell_trace_alloc);
_leave(" = %p", cell);
return cell;
parse_failed:
if (ret == -EINVAL)
printk(KERN_ERR "kAFS: bad VL server IP address\n");
error:
kfree(cell->name);
kfree(cell);
_leave(" = %d", ret);
return ERR_PTR(ret);
}
/*
* afs_lookup_cell - Look up or create a cell record.
* @net: The network namespace
* @name: The name of the cell.
* @namesz: The strlen of the cell name.
* @vllist: A colon/comma separated list of numeric IP addresses or NULL.
* @excl: T if an error should be given if the cell name already exists.
*
* Look up a cell record by name and query the DNS for VL server addresses if
* needed. Note that that actual DNS query is punted off to the manager thread
* so that this function can return immediately if interrupted whilst allowing
* cell records to be shared even if not yet fully constructed.
*/
struct afs_cell *afs_lookup_cell(struct afs_net *net,
const char *name, unsigned int namesz,
const char *vllist, bool excl)
{
struct afs_cell *cell, *candidate, *cursor;
struct rb_node *parent, **pp;
enum afs_cell_state state;
int ret, n;
_enter("%s,%s", name, vllist);
if (!excl) {
cell = afs_find_cell(net, name, namesz, afs_cell_trace_use_lookup);
if (!IS_ERR(cell))
goto wait_for_cell;
}
/* Assume we're probably going to create a cell and preallocate and
* mostly set up a candidate record. We can then use this to stash the
* name, the net namespace and VL server addresses.
*
* We also want to do this before we hold any locks as it may involve
* upcalling to userspace to make DNS queries.
*/
candidate = afs_alloc_cell(net, name, namesz, vllist);
if (IS_ERR(candidate)) {
_leave(" = %ld", PTR_ERR(candidate));
return candidate;
}
/* Find the insertion point and check to see if someone else added a
* cell whilst we were allocating.
*/
down_write(&net->cells_lock);
pp = &net->cells.rb_node;
parent = NULL;
while (*pp) {
parent = *pp;
cursor = rb_entry(parent, struct afs_cell, net_node);
n = strncasecmp(cursor->name, name,
min_t(size_t, cursor->name_len, namesz));
if (n == 0)
n = cursor->name_len - namesz;
if (n < 0)
pp = &(*pp)->rb_left;
else if (n > 0)
pp = &(*pp)->rb_right;
else
goto cell_already_exists;
}
cell = candidate;
candidate = NULL;
atomic_set(&cell->active, 2);
trace_afs_cell(cell->debug_id, refcount_read(&cell->ref), 2, afs_cell_trace_insert);
rb_link_node_rcu(&cell->net_node, parent, pp);
rb_insert_color(&cell->net_node, &net->cells);
up_write(&net->cells_lock);
afs_queue_cell(cell, afs_cell_trace_get_queue_new);
wait_for_cell:
trace_afs_cell(cell->debug_id, refcount_read(&cell->ref), atomic_read(&cell->active),
afs_cell_trace_wait);
_debug("wait_for_cell");
wait_var_event(&cell->state,
({
state = smp_load_acquire(&cell->state); /* vs error */
state == AFS_CELL_ACTIVE || state == AFS_CELL_REMOVED;
}));
/* Check the state obtained from the wait check. */
if (state == AFS_CELL_REMOVED) {
ret = cell->error;
goto error;
}
_leave(" = %p [cell]", cell);
return cell;
cell_already_exists:
_debug("cell exists");
cell = cursor;
if (excl) {
ret = -EEXIST;
} else {
afs_use_cell(cursor, afs_cell_trace_use_lookup);
ret = 0;
}
up_write(&net->cells_lock);
if (candidate)
afs_put_cell(candidate, afs_cell_trace_put_candidate);
if (ret == 0)
goto wait_for_cell;
goto error_noput;
error:
afs_unuse_cell(net, cell, afs_cell_trace_unuse_lookup);
error_noput:
_leave(" = %d [error]", ret);
return ERR_PTR(ret);
}
/*
* set the root cell information
* - can be called with a module parameter string
* - can be called from a write to /proc/fs/afs/rootcell
*/
int afs_cell_init(struct afs_net *net, const char *rootcell)
{
struct afs_cell *old_root, *new_root;
const char *cp, *vllist;
size_t len;
_enter("");
if (!rootcell) {
/* module is loaded with no parameters, or built statically.
* - in the future we might initialize cell DB here.
*/
_leave(" = 0 [no root]");
return 0;
}
cp = strchr(rootcell, ':');
if (!cp) {
_debug("kAFS: no VL server IP addresses specified");
vllist = NULL;
len = strlen(rootcell);
} else {
vllist = cp + 1;
len = cp - rootcell;
}
/* allocate a cell record for the root cell */
new_root = afs_lookup_cell(net, rootcell, len, vllist, false);
if (IS_ERR(new_root)) {
_leave(" = %ld", PTR_ERR(new_root));
return PTR_ERR(new_root);
}
if (!test_and_set_bit(AFS_CELL_FL_NO_GC, &new_root->flags))
afs_use_cell(new_root, afs_cell_trace_use_pin);
/* install the new cell */
down_write(&net->cells_lock);
afs_see_cell(new_root, afs_cell_trace_see_ws);
old_root = net->ws_cell;
net->ws_cell = new_root;
up_write(&net->cells_lock);
afs_unuse_cell(net, old_root, afs_cell_trace_unuse_ws);
_leave(" = 0");
return 0;
}
/*
* Update a cell's VL server address list from the DNS.
*/
static int afs_update_cell(struct afs_cell *cell)
{
struct afs_vlserver_list *vllist, *old = NULL, *p;
unsigned int min_ttl = READ_ONCE(afs_cell_min_ttl);
unsigned int max_ttl = READ_ONCE(afs_cell_max_ttl);
time64_t now, expiry = 0;
int ret = 0;
_enter("%s", cell->name);
vllist = afs_dns_query(cell, &expiry);
if (IS_ERR(vllist)) {
ret = PTR_ERR(vllist);
_debug("%s: fail %d", cell->name, ret);
if (ret == -ENOMEM)
goto out_wake;
ret = -ENOMEM;
vllist = afs_alloc_vlserver_list(0);
if (!vllist)
goto out_wake;
switch (ret) {
case -ENODATA:
case -EDESTADDRREQ:
vllist->status = DNS_LOOKUP_GOT_NOT_FOUND;
break;
case -EAGAIN:
case -ECONNREFUSED:
vllist->status = DNS_LOOKUP_GOT_TEMP_FAILURE;
break;
default:
vllist->status = DNS_LOOKUP_GOT_LOCAL_FAILURE;
break;
}
}
_debug("%s: got list %d %d", cell->name, vllist->source, vllist->status);
cell->dns_status = vllist->status;
now = ktime_get_real_seconds();
if (min_ttl > max_ttl)
max_ttl = min_ttl;
if (expiry < now + min_ttl)
expiry = now + min_ttl;
else if (expiry > now + max_ttl)
expiry = now + max_ttl;
_debug("%s: status %d", cell->name, vllist->status);
if (vllist->source == DNS_RECORD_UNAVAILABLE) {
switch (vllist->status) {
case DNS_LOOKUP_GOT_NOT_FOUND:
/* The DNS said that the cell does not exist or there
* weren't any addresses to be had.
*/
cell->dns_expiry = expiry;
break;
case DNS_LOOKUP_BAD:
case DNS_LOOKUP_GOT_LOCAL_FAILURE:
case DNS_LOOKUP_GOT_TEMP_FAILURE:
case DNS_LOOKUP_GOT_NS_FAILURE:
default:
cell->dns_expiry = now + 10;
break;
}
} else {
cell->dns_expiry = expiry;
}
/* Replace the VL server list if the new record has servers or the old
* record doesn't.
*/
write_lock(&cell->vl_servers_lock);
p = rcu_dereference_protected(cell->vl_servers, true);
if (vllist->nr_servers > 0 || p->nr_servers == 0) {
rcu_assign_pointer(cell->vl_servers, vllist);
cell->dns_source = vllist->source;
old = p;
}
write_unlock(&cell->vl_servers_lock);
afs_put_vlserverlist(cell->net, old);
out_wake:
smp_store_release(&cell->dns_lookup_count,
cell->dns_lookup_count + 1); /* vs source/status */
wake_up_var(&cell->dns_lookup_count);
_leave(" = %d", ret);
return ret;
}
/*
* Destroy a cell record
*/
static void afs_cell_destroy(struct rcu_head *rcu)
{
struct afs_cell *cell = container_of(rcu, struct afs_cell, rcu);
struct afs_net *net = cell->net;
int r;
_enter("%p{%s}", cell, cell->name);
r = refcount_read(&cell->ref);
ASSERTCMP(r, ==, 0);
trace_afs_cell(cell->debug_id, r, atomic_read(&cell->active), afs_cell_trace_free);
afs_put_vlserverlist(net, rcu_access_pointer(cell->vl_servers));
afs_unuse_cell(net, cell->alias_of, afs_cell_trace_unuse_alias);
key_put(cell->anonymous_key);
kfree(cell->name);
kfree(cell);
afs_dec_cells_outstanding(net);
_leave(" [destroyed]");
}
/*
* Queue the cell manager.
*/
static void afs_queue_cell_manager(struct afs_net *net)
{
int outstanding = atomic_inc_return(&net->cells_outstanding);
_enter("%d", outstanding);
if (!queue_work(afs_wq, &net->cells_manager))
afs_dec_cells_outstanding(net);
}
/*
* Cell management timer. We have an increment on cells_outstanding that we
* need to pass along to the work item.
*/
void afs_cells_timer(struct timer_list *timer)
{
struct afs_net *net = container_of(timer, struct afs_net, cells_timer);
_enter("");
if (!queue_work(afs_wq, &net->cells_manager))
afs_dec_cells_outstanding(net);
}
/*
* Get a reference on a cell record.
*/
struct afs_cell *afs_get_cell(struct afs_cell *cell, enum afs_cell_trace reason)
{
int r;
__refcount_inc(&cell->ref, &r);
trace_afs_cell(cell->debug_id, r + 1, atomic_read(&cell->active), reason);
return cell;
}
/*
* Drop a reference on a cell record.
*/
void afs_put_cell(struct afs_cell *cell, enum afs_cell_trace reason)
{
if (cell) {
unsigned int debug_id = cell->debug_id;
unsigned int a;
bool zero;
int r;
a = atomic_read(&cell->active);
zero = __refcount_dec_and_test(&cell->ref, &r);
trace_afs_cell(debug_id, r - 1, a, reason);
if (zero) {
a = atomic_read(&cell->active);
WARN(a != 0, "Cell active count %u > 0\n", a);
call_rcu(&cell->rcu, afs_cell_destroy);
}
}
}
/*
* Note a cell becoming more active.
*/
struct afs_cell *afs_use_cell(struct afs_cell *cell, enum afs_cell_trace reason)
{
int r, a;
r = refcount_read(&cell->ref);
WARN_ON(r == 0);
a = atomic_inc_return(&cell->active);
trace_afs_cell(cell->debug_id, r, a, reason);
return cell;
}
/*
* Record a cell becoming less active. When the active counter reaches 1, it
* is scheduled for destruction, but may get reactivated.
*/
void afs_unuse_cell(struct afs_net *net, struct afs_cell *cell, enum afs_cell_trace reason)
{
unsigned int debug_id;
time64_t now, expire_delay;
int r, a;
if (!cell)
return;
_enter("%s", cell->name);
now = ktime_get_real_seconds();
cell->last_inactive = now;
expire_delay = 0;
if (cell->vl_servers->nr_servers)
expire_delay = afs_cell_gc_delay;
debug_id = cell->debug_id;
r = refcount_read(&cell->ref);
a = atomic_dec_return(&cell->active);
trace_afs_cell(debug_id, r, a, reason);
WARN_ON(a == 0);
if (a == 1)
/* 'cell' may now be garbage collected. */
afs_set_cell_timer(net, expire_delay);
}
/*
* Note that a cell has been seen.
*/
void afs_see_cell(struct afs_cell *cell, enum afs_cell_trace reason)
{
int r, a;
r = refcount_read(&cell->ref);
a = atomic_read(&cell->active);
trace_afs_cell(cell->debug_id, r, a, reason);
}
/*
* Queue a cell for management, giving the workqueue a ref to hold.
*/
void afs_queue_cell(struct afs_cell *cell, enum afs_cell_trace reason)
{
afs_get_cell(cell, reason);
if (!queue_work(afs_wq, &cell->manager))
afs_put_cell(cell, afs_cell_trace_put_queue_fail);
}
/*
* Allocate a key to use as a placeholder for anonymous user security.
*/
static int afs_alloc_anon_key(struct afs_cell *cell)
{
struct key *key;
char keyname[4 + AFS_MAXCELLNAME + 1], *cp, *dp;
/* Create a key to represent an anonymous user. */
memcpy(keyname, "afs@", 4);
dp = keyname + 4;
cp = cell->name;
do {
*dp++ = tolower(*cp);
} while (*cp++);
key = rxrpc_get_null_key(keyname);
if (IS_ERR(key))
return PTR_ERR(key);
cell->anonymous_key = key;
_debug("anon key %p{%x}",
cell->anonymous_key, key_serial(cell->anonymous_key));
return 0;
}
/*
* Activate a cell.
*/
static int afs_activate_cell(struct afs_net *net, struct afs_cell *cell)
{
struct hlist_node **p;
struct afs_cell *pcell;
int ret;
if (!cell->anonymous_key) {
ret = afs_alloc_anon_key(cell);
if (ret < 0)
return ret;
}
ret = afs_proc_cell_setup(cell);
if (ret < 0)
return ret;
mutex_lock(&net->proc_cells_lock);
for (p = &net->proc_cells.first; *p; p = &(*p)->next) {
pcell = hlist_entry(*p, struct afs_cell, proc_link);
if (strcmp(cell->name, pcell->name) < 0)
break;
}
cell->proc_link.pprev = p;
cell->proc_link.next = *p;
rcu_assign_pointer(*p, &cell->proc_link.next);
if (cell->proc_link.next)
cell->proc_link.next->pprev = &cell->proc_link.next;
afs_dynroot_mkdir(net, cell);
mutex_unlock(&net->proc_cells_lock);
return 0;
}
/*
* Deactivate a cell.
*/
static void afs_deactivate_cell(struct afs_net *net, struct afs_cell *cell)
{
_enter("%s", cell->name);
afs_proc_cell_remove(cell);
mutex_lock(&net->proc_cells_lock);
hlist_del_rcu(&cell->proc_link);
afs_dynroot_rmdir(net, cell);
mutex_unlock(&net->proc_cells_lock);
_leave("");
}
/*
* Manage a cell record, initialising and destroying it, maintaining its DNS
* records.
*/
static void afs_manage_cell(struct afs_cell *cell)
{
struct afs_net *net = cell->net;
int ret, active;
_enter("%s", cell->name);
again:
_debug("state %u", cell->state);
switch (cell->state) {
case AFS_CELL_INACTIVE:
case AFS_CELL_FAILED:
down_write(&net->cells_lock);
active = 1;
if (atomic_try_cmpxchg_relaxed(&cell->active, &active, 0)) {
rb_erase(&cell->net_node, &net->cells);
trace_afs_cell(cell->debug_id, refcount_read(&cell->ref), 0,
afs_cell_trace_unuse_delete);
smp_store_release(&cell->state, AFS_CELL_REMOVED);
}
up_write(&net->cells_lock);
if (cell->state == AFS_CELL_REMOVED) {
wake_up_var(&cell->state);
goto final_destruction;
}
if (cell->state == AFS_CELL_FAILED)
goto done;
smp_store_release(&cell->state, AFS_CELL_UNSET);
wake_up_var(&cell->state);
goto again;
case AFS_CELL_UNSET:
smp_store_release(&cell->state, AFS_CELL_ACTIVATING);
wake_up_var(&cell->state);
goto again;
case AFS_CELL_ACTIVATING:
ret = afs_activate_cell(net, cell);
if (ret < 0)
goto activation_failed;
smp_store_release(&cell->state, AFS_CELL_ACTIVE);
wake_up_var(&cell->state);
goto again;
case AFS_CELL_ACTIVE:
if (atomic_read(&cell->active) > 1) {
if (test_and_clear_bit(AFS_CELL_FL_DO_LOOKUP, &cell->flags)) {
ret = afs_update_cell(cell);
if (ret < 0)
cell->error = ret;
}
goto done;
}
smp_store_release(&cell->state, AFS_CELL_DEACTIVATING);
wake_up_var(&cell->state);
goto again;
case AFS_CELL_DEACTIVATING:
if (atomic_read(&cell->active) > 1)
goto reverse_deactivation;
afs_deactivate_cell(net, cell);
smp_store_release(&cell->state, AFS_CELL_INACTIVE);
wake_up_var(&cell->state);
goto again;
case AFS_CELL_REMOVED:
goto done;
default:
break;
}
_debug("bad state %u", cell->state);
BUG(); /* Unhandled state */
activation_failed:
cell->error = ret;
afs_deactivate_cell(net, cell);
smp_store_release(&cell->state, AFS_CELL_FAILED); /* vs error */
wake_up_var(&cell->state);
goto again;
reverse_deactivation:
smp_store_release(&cell->state, AFS_CELL_ACTIVE);
wake_up_var(&cell->state);
_leave(" [deact->act]");
return;
done:
_leave(" [done %u]", cell->state);
return;
final_destruction:
/* The root volume is pinning the cell */
afs_put_volume(cell->net, cell->root_volume, afs_volume_trace_put_cell_root);
cell->root_volume = NULL;
afs_put_cell(cell, afs_cell_trace_put_destroy);
}
static void afs_manage_cell_work(struct work_struct *work)
{
struct afs_cell *cell = container_of(work, struct afs_cell, manager);
afs_manage_cell(cell);
afs_put_cell(cell, afs_cell_trace_put_queue_work);
}
/*
* Manage the records of cells known to a network namespace. This includes
* updating the DNS records and garbage collecting unused cells that were
* automatically added.
*
* Note that constructed cell records may only be removed from net->cells by
* this work item, so it is safe for this work item to stash a cursor pointing
* into the tree and then return to caller (provided it skips cells that are
* still under construction).
*
* Note also that we were given an increment on net->cells_outstanding by
* whoever queued us that we need to deal with before returning.
*/
void afs_manage_cells(struct work_struct *work)
{
struct afs_net *net = container_of(work, struct afs_net, cells_manager);
struct rb_node *cursor;
time64_t now = ktime_get_real_seconds(), next_manage = TIME64_MAX;
bool purging = !net->live;
_enter("");
/* Trawl the cell database looking for cells that have expired from
* lack of use and cells whose DNS results have expired and dispatch
* their managers.
*/
down_read(&net->cells_lock);
for (cursor = rb_first(&net->cells); cursor; cursor = rb_next(cursor)) {
struct afs_cell *cell =
rb_entry(cursor, struct afs_cell, net_node);
unsigned active;
bool sched_cell = false;
active = atomic_read(&cell->active);
trace_afs_cell(cell->debug_id, refcount_read(&cell->ref),
active, afs_cell_trace_manage);
ASSERTCMP(active, >=, 1);
if (purging) {
if (test_and_clear_bit(AFS_CELL_FL_NO_GC, &cell->flags)) {
active = atomic_dec_return(&cell->active);
trace_afs_cell(cell->debug_id, refcount_read(&cell->ref),
active, afs_cell_trace_unuse_pin);
}
}
if (active == 1) {
struct afs_vlserver_list *vllist;
time64_t expire_at = cell->last_inactive;
read_lock(&cell->vl_servers_lock);
vllist = rcu_dereference_protected(
cell->vl_servers,
lockdep_is_held(&cell->vl_servers_lock));
if (vllist->nr_servers > 0)
expire_at += afs_cell_gc_delay;
read_unlock(&cell->vl_servers_lock);
if (purging || expire_at <= now)
sched_cell = true;
else if (expire_at < next_manage)
next_manage = expire_at;
}
if (!purging) {
if (test_bit(AFS_CELL_FL_DO_LOOKUP, &cell->flags))
sched_cell = true;
}
if (sched_cell)
afs_queue_cell(cell, afs_cell_trace_get_queue_manage);
}
up_read(&net->cells_lock);
/* Update the timer on the way out. We have to pass an increment on
* cells_outstanding in the namespace that we are in to the timer or
* the work scheduler.
*/
if (!purging && next_manage < TIME64_MAX) {
now = ktime_get_real_seconds();
if (next_manage - now <= 0) {
if (queue_work(afs_wq, &net->cells_manager))
atomic_inc(&net->cells_outstanding);
} else {
afs_set_cell_timer(net, next_manage - now);
}
}
afs_dec_cells_outstanding(net);
_leave(" [%d]", atomic_read(&net->cells_outstanding));
}
/*
* Purge in-memory cell database.
*/
void afs_cell_purge(struct afs_net *net)
{
struct afs_cell *ws;
_enter("");
down_write(&net->cells_lock);
ws = net->ws_cell;
net->ws_cell = NULL;
up_write(&net->cells_lock);
afs_unuse_cell(net, ws, afs_cell_trace_unuse_ws);
_debug("del timer");
if (del_timer_sync(&net->cells_timer))
atomic_dec(&net->cells_outstanding);
_debug("kick mgr");
afs_queue_cell_manager(net);
_debug("wait");
wait_var_event(&net->cells_outstanding,
!atomic_read(&net->cells_outstanding));
_leave("");
}
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